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Sample records for invasion decreases diversity

  1. Changes in soil diversity and global activities following invasions of the exotic invasive plant, Amaranthus viridis L., decrease the growth of native sahelian Acacia species.

    PubMed

    Sanon, Arsene; Béguiristain, Thierry; Cébron, Aurelie; Berthelin, Jacques; Ndoye, Ibrahima; Leyval, Corinne; Sylla, Samba; Duponnois, Robin

    2009-10-01

    The objectives of this study were to determine whether the invasive plant Amaranthus viridis influenced soil microbial and chemical properties and to assess the consequences of these modifications on native plant growth. The experiment was conducted in Senegal at two sites: one invaded by A. viridis and the other covered by other plant species. Soil nutrient contents as well as microbial community density, diversity and functions were measured. Additionally, five sahelian Acacia species were grown in (1) soil disinfected or not collected from both sites, (2) uninvaded soil exposed to an A. viridis plant aqueous extract and (3) soil collected from invaded and uninvaded sites and inoculated or not with the arbuscular mycorrhizal (AM) fungus Glomus intraradices. The results showed that the invasion of A. viridis increased soil nutrient availability, bacterial abundance and microbial activities. In contrast, AM fungi and rhizobial development and the growth of Acacia species were severely reduced in A. viridis-invaded soil. Amaranthus viridis aqueous extract also exhibited an inhibitory effect on rhizobial growth, indicating an antibacterial activity of this plant extract. However, the inoculation of G. intraradices was highly beneficial to the growth and nodulation of Acacia species. These results highlight the role of AM symbiosis in the processes involved in plant coexistence and in ecosystem management programs that target preservation of native plant diversity.

  2. Endemic predators, invasive prey and native diversity

    PubMed Central

    Wanger, Thomas C.; Wielgoss, Arno C.; Motzke, Iris; Clough, Yann; Brook, Barry W.; Sodhi, Navjot S.; Tscharntke, Teja

    2011-01-01

    Interactions between native diversity and invasive species can be more complex than is currently understood. Invasive ant species often substantially reduce diversity in the native ants diversity that act as natural control agents for pest insects. In Indonesia (on the island of Sulawesi), the third largest cacao producer worldwide, we show that a predatory endemic toad (Ingerophrynus celebensis) controls invasive ant (Anoplolepis gracilipes) abundance, and positively affects native ant diversity. We call this the invasive-naivety effect (an opposite of enemy release), whereby alien species may not harbour anti-predatory defences against a novel native predator. A positive effect of the toads on native ants may facilitate their predation on insect vectors of cacao diseases. Hence, toads may increase crop yield, but further research is needed on this aspect. Ironically, amphibians are globally the most threatened vertebrate class and are strongly impacted by the conversion of rainforest to cacao plantations in Sulawesi. It is, therefore, crucial to manage cacao plantations to maintain these endemic toads, as they may provide critical ecosystem services, such as invasion resistance and preservation of native insect diversity. PMID:20826488

  3. SPARC Promotes Cell Invasion In Vivo by Decreasing Type IV Collagen Levels in the Basement Membrane.

    PubMed

    Morrissey, Meghan A; Jayadev, Ranjay; Miley, Ginger R; Blebea, Catherine A; Chi, Qiuyi; Ihara, Shinji; Sherwood, David R

    2016-02-01

    Overexpression of SPARC, a collagen-binding glycoprotein, is strongly associated with tumor invasion through extracellular matrix in many aggressive cancers. SPARC regulates numerous cellular processes including integrin-mediated cell adhesion, cell signaling pathways, and extracellular matrix assembly; however, the mechanism by which SPARC promotes cell invasion in vivo remains unclear. A main obstacle in understanding SPARC function has been the difficulty of visualizing and experimentally examining the dynamic interactions between invasive cells, extracellular matrix and SPARC in native tissue environments. Using the model of anchor cell invasion through the basement membrane (BM) extracellular matrix in Caenorhabditis elegans, we find that SPARC overexpression is highly pro-invasive and rescues BM transmigration in mutants with defects in diverse aspects of invasion, including cell polarity, invadopodia formation, and matrix metalloproteinase expression. By examining BM assembly, we find that overexpression of SPARC specifically decreases levels of BM type IV collagen, a crucial structural BM component. Reduction of type IV collagen mimicked SPARC overexpression and was sufficient to promote invasion. Tissue-specific overexpression and photobleaching experiments revealed that SPARC acts extracellularly to inhibit collagen incorporation into BM. By reducing endogenous SPARC, we also found that SPARC functions normally to traffic collagen from its site of synthesis to tissues that do not express collagen. We propose that a surplus of SPARC disrupts extracellular collagen trafficking and reduces BM collagen incorporation, thus weakening the BM barrier and dramatically enhancing its ability to be breached by invasive cells. PMID:26926673

  4. SPARC Promotes Cell Invasion In Vivo by Decreasing Type IV Collagen Levels in the Basement Membrane

    PubMed Central

    Morrissey, Meghan A.; Jayadev, Ranjay; Miley, Ginger R.; Blebea, Catherine A.; Chi, Qiuyi; Ihara, Shinji; Sherwood, David R.

    2016-01-01

    Overexpression of SPARC, a collagen-binding glycoprotein, is strongly associated with tumor invasion through extracellular matrix in many aggressive cancers. SPARC regulates numerous cellular processes including integrin-mediated cell adhesion, cell signaling pathways, and extracellular matrix assembly; however, the mechanism by which SPARC promotes cell invasion in vivo remains unclear. A main obstacle in understanding SPARC function has been the difficulty of visualizing and experimentally examining the dynamic interactions between invasive cells, extracellular matrix and SPARC in native tissue environments. Using the model of anchor cell invasion through the basement membrane (BM) extracellular matrix in Caenorhabditis elegans, we find that SPARC overexpression is highly pro-invasive and rescues BM transmigration in mutants with defects in diverse aspects of invasion, including cell polarity, invadopodia formation, and matrix metalloproteinase expression. By examining BM assembly, we find that overexpression of SPARC specifically decreases levels of BM type IV collagen, a crucial structural BM component. Reduction of type IV collagen mimicked SPARC overexpression and was sufficient to promote invasion. Tissue-specific overexpression and photobleaching experiments revealed that SPARC acts extracellularly to inhibit collagen incorporation into BM. By reducing endogenous SPARC, we also found that SPARC functions normally to traffic collagen from its site of synthesis to tissues that do not express collagen. We propose that a surplus of SPARC disrupts extracellular collagen trafficking and reduces BM collagen incorporation, thus weakening the BM barrier and dramatically enhancing its ability to be breached by invasive cells. PMID:26926673

  5. Habitat fragmentation, tree diversity, and plant invasion interact to structure forest caterpillar communities.

    PubMed

    Stireman, John O; Devlin, Hilary; Doyle, Annie L

    2014-09-01

    Habitat fragmentation and invasive species are two of the most prominent threats to terrestrial ecosystems. Few studies have examined how these factors interact to influence the diversity of natural communities, particularly primary consumers. Here, we examined the effects of forest fragmentation and invasion of exotic honeysuckle (Lonicera maackii, Caprifoliaceae) on the abundance and diversity of the dominant forest herbivores: woody plant-feeding Lepidoptera. We systematically surveyed understory caterpillars along transects in 19 forest fragments over multiple years in southwestern Ohio and evaluated how fragment area, isolation, tree diversity, invasion by honeysuckle and interactions among these factors influence species richness, diversity and abundance. We found strong seasonal variation in caterpillar communities, which responded differently to fragmentation and invasion. Abundance and richness increased with fragment area, but these effects were mitigated by high levels of honeysuckle, tree diversity, landscape forest cover, and large recent changes in area. Honeysuckle infestation was generally associated with decreased caterpillar abundance and diversity, but these effects were strongly dependent on other fragment traits. Effects of honeysuckle on abundance were moderated when fragment area, landscape forest cover and tree diversity were high. In contrast, negative effects of honeysuckle invasion on caterpillar diversity were most pronounced in fragments with high tree diversity and large recent increases in area. Our results illustrate the complex interdependencies of habitat fragmentation, plant diversity and plant invasion in their effects on primary consumers and emphasize the need to consider these processes in concert to understand the consequences of anthropogenic habitat change for biodiversity. PMID:25015121

  6. Tree Diversity Limits the Impact of an Invasive Forest Pest.

    PubMed

    Guyot, Virginie; Castagneyrol, Bastien; Vialatte, Aude; Deconchat, Marc; Selvi, Federico; Bussotti, Filippo; Jactel, Hervé

    2015-01-01

    The impact of invasive herbivore species may be lower in more diverse plant communities due to mechanisms of associational resistance. According to the "resource concentration hypothesis" the amount and accessibility of host plants is reduced in diverse plant communities, thus limiting the exploitation of resources by consumers. In addition, the "natural enemy hypothesis" suggests that richer plant assemblages provide natural enemies with more complementary resources and habitats, thus promoting top down regulation of herbivores. We tested these two hypotheses by comparing crown damage by the invasive Asian chestnut gall wasp (Dryocosmus kuriphilus) on chestnut trees (Castanea sativa) in pure and mixed stands in Italy. We estimated the defoliation on 70 chestnut trees in 15 mature stands sampled in the same region along a gradient of tree species richness ranging from one species (chestnut monocultures) to four species (mixtures of chestnut and three broadleaved species). Chestnut defoliation was significantly lower in stands with higher tree diversity. Damage on individual chestnut trees decreased with increasing height of neighboring, heterospecific trees. These results suggest that conservation biological control method based on tree species mixtures might help to reduce the impact of the Asian chestnut gall. PMID:26360881

  7. Tree Diversity Limits the Impact of an Invasive Forest Pest

    PubMed Central

    Guyot, Virginie; Castagneyrol, Bastien; Vialatte, Aude; Deconchat, Marc; Selvi, Federico; Bussotti, Filippo; Jactel, Hervé

    2015-01-01

    The impact of invasive herbivore species may be lower in more diverse plant communities due to mechanisms of associational resistance. According to the “resource concentration hypothesis” the amount and accessibility of host plants is reduced in diverse plant communities, thus limiting the exploitation of resources by consumers. In addition, the “natural enemy hypothesis” suggests that richer plant assemblages provide natural enemies with more complementary resources and habitats, thus promoting top down regulation of herbivores. We tested these two hypotheses by comparing crown damage by the invasive Asian chestnut gall wasp (Dryocosmus kuriphilus) on chestnut trees (Castanea sativa) in pure and mixed stands in Italy. We estimated the defoliation on 70 chestnut trees in 15 mature stands sampled in the same region along a gradient of tree species richness ranging from one species (chestnut monocultures) to four species (mixtures of chestnut and three broadleaved species). Chestnut defoliation was significantly lower in stands with higher tree diversity. Damage on individual chestnut trees decreased with increasing height of neighboring, heterospecific trees. These results suggest that conservation biological control method based on tree species mixtures might help to reduce the impact of the Asian chestnut gall. PMID:26360881

  8. Tree Diversity Limits the Impact of an Invasive Forest Pest.

    PubMed

    Guyot, Virginie; Castagneyrol, Bastien; Vialatte, Aude; Deconchat, Marc; Selvi, Federico; Bussotti, Filippo; Jactel, Hervé

    2015-01-01

    The impact of invasive herbivore species may be lower in more diverse plant communities due to mechanisms of associational resistance. According to the "resource concentration hypothesis" the amount and accessibility of host plants is reduced in diverse plant communities, thus limiting the exploitation of resources by consumers. In addition, the "natural enemy hypothesis" suggests that richer plant assemblages provide natural enemies with more complementary resources and habitats, thus promoting top down regulation of herbivores. We tested these two hypotheses by comparing crown damage by the invasive Asian chestnut gall wasp (Dryocosmus kuriphilus) on chestnut trees (Castanea sativa) in pure and mixed stands in Italy. We estimated the defoliation on 70 chestnut trees in 15 mature stands sampled in the same region along a gradient of tree species richness ranging from one species (chestnut monocultures) to four species (mixtures of chestnut and three broadleaved species). Chestnut defoliation was significantly lower in stands with higher tree diversity. Damage on individual chestnut trees decreased with increasing height of neighboring, heterospecific trees. These results suggest that conservation biological control method based on tree species mixtures might help to reduce the impact of the Asian chestnut gall.

  9. Curvilinear effects of invasive plants on plant diversity: plant community invaded by Sphagneticola trilobata.

    PubMed

    Qi, Shan-Shan; Dai, Zhi-Cong; Zhai, De-Li; Chen, Si-Chong; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Zhong, Qiong-Xin; Du, Dao-Lin

    2014-01-01

    The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%), compared with the native plants (over 60%). Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants.

  10. Curvilinear Effects of Invasive Plants on Plant Diversity: Plant Community Invaded by Sphagneticola trilobata

    PubMed Central

    Zhai, De-Li; Chen, Si-Chong; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Zhong, Qiong-Xin; Du, Dao-Lin

    2014-01-01

    The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%), compared with the native plants (over 60%). Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants. PMID:25426856

  11. Curvilinear effects of invasive plants on plant diversity: plant community invaded by Sphagneticola trilobata.

    PubMed

    Qi, Shan-Shan; Dai, Zhi-Cong; Zhai, De-Li; Chen, Si-Chong; Si, Chun-Can; Huang, Ping; Wang, Rui-Ping; Zhong, Qiong-Xin; Du, Dao-Lin

    2014-01-01

    The effects of invasive plants on the species diversity of plant communities are controversial, showing either a positive or negative linear relationship. Based on community data collected from forty 5 m×5 m plots invaded by Sphagneticola trilobata in eight cities across Hainan Island, China, we found S. trilobata decreased plant community diversity once its cover was beyond 10%. We demonstrated that the effects of invasive/native plants on the plant diversity of communities invaded by S. trilobata were curvilinear. These effects, which showed peaks under different degrees of vegetation cover, appeared not only for S. trilobata and all invasive plants, but also for all native plants. Invasive plants primarily had negative effects on plant diversity when they became abundant at a much lower cover level (less than 35%), compared with the native plants (over 60%). Thus, it is necessary to distinguish a range for assessing the effects of plants, especially invasive plants. Our results also confirmed that the invasion intensity of invasive alien plants increased with the intensity of local economic development. We highlight and further discuss the critical importance of curvilinear effects of biological invasion to provide ideas regarding the conservation of local biodiversity and the management of invasive plants. PMID:25426856

  12. Parasites and genetic diversity in an invasive bumblebee

    PubMed Central

    Jones, Catherine M; Brown, Mark J F; Ings, Thomas

    2014-01-01

    Biological invasions are facilitated by the global transportation of species and climate change. Given that invasions may cause ecological and economic damage and pose a major threat to biodiversity, understanding the mechanisms behind invasion success is essential. Both the release of non-native populations from natural enemies, such as parasites, and the genetic diversity of these populations may play key roles in their invasion success. We investigated the roles of parasite communities, through enemy release and parasite acquisition, and genetic diversity in the invasion success of the non-native bumblebee, Bombus hypnorum, in the United Kingdom. The invasive B. hypnorum had higher parasite prevalence than most, or all native congeners for two high-impact parasites, probably due to higher susceptibility and parasite acquisition. Consequently parasites had a higher impact on B. hypnorum queens’ survival and colony-founding success than on native species. Bombus hypnorum also had lower functional genetic diversity at the sex-determining locus than native species. Higher parasite prevalence and lower genetic diversity have not prevented the rapid invasion of the United Kingdom by B. hypnorum. These data may inform our understanding of similar invasions by commercial bumblebees around the world. This study suggests that concerns about parasite impacts on the small founding populations common to re-introduction and translocation programs may be less important than currently believed. PMID:24749545

  13. Severe plant invasions can increase mycorrhizal fungal abundance and diversity.

    PubMed

    Lekberg, Ylva; Gibbons, Sean M; Rosendahl, Søren; Ramsey, Philip W

    2013-07-01

    Invasions by non-native plants can alter ecosystem functions and reduce native plant diversity, but relatively little is known about their effect on belowground microbial communities. We show that invasions by knapweed (Centaurea stoebe) and leafy spurge (Euphorbia esula, hereafter spurge)--but not cheatgrass (Bromus tectorum)--support a higher abundance and diversity of symbiotic arbuscular mycorrhizal fungi (AMF) than multi-species native plant communities. The higher AMF richness associated with knapweed and spurge is unlikely due to a co-invasion by AMF, because a separate sampling showed that individual native forbs hosted a similar AMF abundance and richness as exotic forbs. Native grasses associated with fewer AMF taxa, which could explain the reduced AMF richness in native, grass-dominated communities. The three invasive plant species harbored distinct AMF communities, and analyses of co-occurring native and invasive plants indicate that differences were partly driven by the invasive plants and were not the result of pre-invasion conditions. Our results suggest that invasions by mycotrophic plants that replace poorer hosts can increase AMF abundance and richness. The high AMF richness in monodominant plant invasions also indicates that the proposed positive relationship between above and belowground diversity is not always strong. Finally, the disparate responses among exotic plants and consistent results between grasses and forbs suggest that AMF respond more to plant functional group than plant provenance.

  14. Genetic diversity is positively associated with fine-scale momentary abundance of an invasive ant

    PubMed Central

    Gruber, Monica A M; Hoffmann, Benjamin D; Ritchie, Peter A; Lester, Philip J

    2012-01-01

    Many introduced species become invasive despite genetic bottlenecks that should, in theory, decrease the chances of invasion success. By contrast, population genetic bottlenecks have been hypothesized to increase the invasion success of unicolonial ants by increasing the genetic similarity between descendent populations, thus promoting co-operation. We investigated these alternate hypotheses in the unicolonial yellow crazy ant, Anoplolepis gracilipes, which has invaded Arnhem Land in Australia's Northern Territory. We used momentary abundance as a surrogate measure of invasion success, and investigated the relationship between A. gracilipes genetic diversity and its abundance, and the effect of its abundance on species diversity and community structure. We also investigated whether selected habitat characteristics contributed to differences in A. gracilipes abundance, for which we found no evidence. Our results revealed a significant positive association between A. gracilipes genetic diversity and abundance. Invaded communities were less diverse and differed in structure from uninvaded communities, and these effects were stronger as A. gracilipes abundance increased. These results contradict the hypothesis that genetic bottlenecks may promote unicoloniality. However, our A. gracilipes study population has diverged since its introduction, which may have obscured evidence of the bottleneck that would likely have occurred on arrival. The relative importance of genetic diversity to invasion success may be context dependent, and the role of genetic diversity may be more obvious in the absence of highly favorable novel ecological conditions. PMID:23139870

  15. Plant species loss decreases arthropod diversity and shifts trophic structure.

    PubMed

    Haddad, Nick M; Crutsinger, Gregory M; Gross, Kevin; Haarstad, John; Knops, Johannes M H; Tilman, David

    2009-10-01

    Plant diversity is predicted to be positively linked to the diversity of herbivores and predators in a foodweb. Yet, the relationship between plant and animal diversity is explained by a variety of competing hypotheses, with mixed empirical results for each hypothesis. We sampled arthropods for over a decade in an experiment that manipulated the number of grassland plant species. We found that herbivore and predator species richness were strongly, positively related to plant species richness, and that these relationships were caused by different mechanisms at herbivore and predator trophic levels. Even more dramatic was the threefold increase, from low- to high-plant species richness, in abundances of predatory and parasitoid arthropods relative to their herbivorous prey. Our results demonstrate that, over the long term, the loss of plant species propagates through food webs, greatly decreasing arthropod species richness, shifting a predator-dominated trophic structure to being herbivore dominated, and likely impacting ecosystem functioning and services.

  16. Sampling and Complementarity Effects of Plant Diversity on Resource Use Increases the Invasion Resistance of Communities

    PubMed Central

    Zhu, Dan H.; Wang, Ping; Zhang, Wei Z.; Yuan, Yue; Li, Bin; Wang, Jiang

    2015-01-01

    Background Although plant diversity is postulated to resist invasion, studies have not provided consistent results, most of which were ascribed to the influences of other covariate environmental factors. Methodology/Principal Findings To explore the mechanisms by which plant diversity influences community invasibility, an experiment was conducted involving grassland sites varying in their species richness (one, two, four, eight, and sixteen species). Light interception efficiency and soil resources (total N, total P, and water content) were measured. The number of species, biomass, and the number of seedlings of the invading species decreased significantly with species richness. The presence of Patrinia scabiosaefolia Fisch. ex Trev. and Mosla dianthera (Buch.-Ham. ex Roxburgh) Maxim. significantly increased the resistance of the communities to invasion. A structural equation model showed that the richness of planted species had no direct and significant effect on invasion. Light interception efficiency had a negative effect on the invasion whereas soil water content had a positive effect. In monocultures, Antenoron filiforme (Thunb.) Rob. et Vaut. showed the highest light interception efficiency and P. scabiosaefolia recorded the lowest soil water content. With increased planted-species richness, a greater percentage of pots showed light use efficiency higher than that of A. filiforme and a lower soil water content than that in P. scabiosaefolia. Conclusions/Significance The results of this study suggest that plant diversity confers resistance to invasion, which is mainly ascribed to the sampling effect of particular species and the complementarity effect among species on resources use. PMID:26556713

  17. Negative per capita effects of two invasive plants, Lythrum salicaria and Phalaris arundinacea, on the moth diversity of wetland communities.

    PubMed

    Schooler, S S; McEvoy, P B; Hammond, P; Coombs, E M

    2009-06-01

    Invasive plants have been shown to negatively affect the diversity of plant communities. However, little is known about the effect of invasive plants on the diversity at other trophic levels. In this study, we examine the per capita effects of two invasive plants, purple loosestrife (Lythrum salicaria) and reed canary grass (Phalaris arundinacea), on moth diversity in wetland communities at 20 sites in the Pacific Northwest, USA. Prior studies document that increasing abundance of these two plant species decreases the diversity of plant communities. We predicted that this reduction in plant diversity would result in reduced herbivore diversity. Four measurements were used to quantify diversity: species richness (S), community evenness (J), Brillouin's index (H) and Simpson's index (D). We identified 162 plant species and 156 moth species across the 20 wetland sites. The number of moth species was positively correlated with the number of plant species. In addition, invasive plant abundance was negatively correlated with species richness of the moth community (linear relationship), and the effect was similar for both invasive plant species. However, no relationship was found between invasive plant abundance and the three other measures of moth diversity (J, H, D) which included moth abundance in their calculation. We conclude that species richness within, and among, trophic levels is adversely affected by these two invasive wetland plant species.

  18. Short-term invasibility patterns in burnt and unburnt experimental Mediterranean grassland communities of varying diversities.

    PubMed

    Dimitrakopoulos, Panayiotis G; Galanidis, Alexandros; Siamantziouras, Akis-Stavros D; Troumbis, Andreas Y

    2005-04-01

    This paper reports the findings of a short-term natural invasibility field study in constructed Mediterranean herbaceous communities of varying diversities, under a fire treatment. Three components of invasibility, i.e. species richness, density and biomass of invaders, have been monitored in burnt and unburnt experimental plots with resident diversity ranging from monocultures to 18-species mixtures. In general, species richness, density and biomass of invaders decreased significantly with the increase of resident species richness. Furthermore, the density and biomass of invading species were significantly influenced by the species composition of resident communities. Although aboveground biomass, leaf area index, canopy height and percent bare ground of the resident communities explained a significant part of the variation in the success of invading species, these covariates did not fully explain the effects of resident species richness. Fire mainly influenced invasibility via soil nutrient levels. The effect of fire on observed invasibility patterns seems to be less important than the effects of resident species richness. Our results demonstrate the importance of species richness and composition in controlling the initial stages of plant invasions in Mediterranean grasslands but that there was a lack of interaction with the effects of fire disturbance. PMID:15711823

  19. Invasive lionfish use a diversity of habitats in Florida

    USGS Publications Warehouse

    Schofield, Pamela J.; Akins, Lad; Gregoire-Lucente, Denise R.; Pawlitz, Rachel J.

    2014-01-01

    Two species of lionfish (Pterois volitans and Pterois miles) are the first marine fishes known to invade and establish self-sustaining populations along the eastern seaboard of the United States. First documented off the coast of Florida in 1985, lionfish are now found along the Atlantic coast of the United States as well as in the Caribbean Sea and Gulf of Mexico. Although long-term effects of this invasion are not yet fully known, there is early evidence that lionfish are negatively impacting native marine life. The lionfish invasion raises questions about which types of habitat the species will occupy in its newly invaded ecosystem. In their native range, lionfish are found primarily on coral reefs but sometimes are found in other habitats such as seagrasses and mangroves. This fact sheet documents the diversity of habitat types in which invasive lionfish have been reported within Florida’s coastal waters, based on lionfish sightings recorded in the U.S. Geological Survey Nonindigenous Aquatic Species database (USGS-NAS).

  20. In situ clinical evidence that zinc levels are decreased in breast invasive ductal carcinoma

    PubMed Central

    Zou, Jing; Franklin, Renty B.

    2016-01-01

    Purpose Altered zinc levels in malignant cells versus their normal cells have important implications in the development and progression of several cancers. Prostate, pancreatic, and hepatocellular carcinomas exhibit consistent marked zinc decrease in situ in the malignant cells, and other cancers (such as kidney, lung, and thyroid) also exhibit decreased tissue zinc levels. However, zinc levels are increased in breast cancer tissue compared to breast normal tissue, and the contemporary dominant view is that zinc is increased in invasive ductal carcinoma. This has important implications regarding the role and effects of zinc in breast malignancy compared to other cancers, which caused us to initiate this study to either confirm or challenge the contemporary view of an increased zinc level in the invasive ductal malignant cells. Methods We employed dithizone staining of breast tissue sections and tissue cores to determine the relative in situ cellular zinc levels specifically in the invasive ductal malignant cells as compared to normal ductal epithelium. This approach had not been employed in any of the reported breast studies. Results The results revealed that the zinc levels are consistently and markedly decreased in the ductal malignant cells as compared with higher prominent zinc levels in the normal ductal epithelium. Decreased zinc is evident in Grade 1 well-differentiated malignancy and in Grade 2 and Grade 3 carcinomas. Among the twenty-five cancer cases in this study, none exhibited increased zinc in the invasive ductal carcinoma compared to the zinc level in the normal ductal epithelium. Conclusions The decreased zinc levels in breast invasive ductal carcinoma is consistent with prostate, pancreatic, and liver carcinomas in which the decrease in zinc is a required event in the development of malignancy to prevent cytotoxicity that would result from the higher zinc levels in the normal cells. This new understanding requires a redirection in elucidating the

  1. Biodiversity loss decreases parasite diversity: theory and patterns.

    PubMed

    Lafferty, Kevin D

    2012-10-19

    Past models have suggested host-parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought.

  2. Biodiversity loss decreases parasite diversity: theory and patterns

    PubMed Central

    Lafferty, Kevin D.

    2012-01-01

    Past models have suggested host–parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought. PMID:22966137

  3. Biodiversity loss decreases parasite diversity: theory and patterns

    USGS Publications Warehouse

    Lafferty, Kevin D.

    2012-01-01

    Past models have suggested host–parasite coextinction could lead to linear, or concave down relationships between free-living species richness and parasite richness. I explored several models for the relationship between parasite richness and biodiversity loss. Life cycle complexity, low generality of parasites and sensitivity of hosts reduced the robustness of parasite species to the loss of free-living species diversity. Food-web complexity and the ordering of extinctions altered these relationships in unpredictable ways. Each disassembly of a food web resulted in a unique relationship between parasite richness and the richness of free-living species, because the extinction trajectory of parasites was sensitive to the order of extinctions of free-living species. However, the average of many disassemblies tended to approximate an analytical model. Parasites of specialist hosts and hosts higher on food chains were more likely to go extinct in food-web models. Furthermore, correlated extinctions between hosts and parasites (e.g. if parasites share a host with a specialist predator) led to steeper declines in parasite richness with biodiversity loss. In empirical food webs with random removals of free-living species, the relationship between free-living species richness and parasite richness was, on average, quasi-linear, suggesting biodiversity loss reduces parasite diversity more than previously thought.

  4. [Effects of Solenopsis invicta invasion on the diversity of spider communities in a corn field].

    PubMed

    Jun, Huang; Yi-Juan, Xu; Yong-Yue, Lu; Ling, Zeng

    2012-04-01

    By using pitfall trapping and ocular estimation, this paper studied the effects of Solenopsis invicta invasion on the diversity of spider communities in a corn field. A total of 16 spider species belonging to 8 families were recorded. In the plot S. invicta invaded, there were 10 spider species of 6 families, among which, 5 species of 4 families were in pesticide-treated plot, and 11 species of 8 families were in control plot. The spiders were dominated by wandering species, mainly belonging to the families Salticidae and Oxyopidae, and the dominant species were Oxyopex sertatus, Myrmarachne joblotii, and Myrmarachne sp. In the plot S. invicta invaded, the population quantity of S. invicta began to increase steadily from the late whorl stage of corn, with the peak (225 individuals) through the earring stage, but decreased steadily thereafter, with the decrement of the spiders of genus Oxyopex reached 79.2%, while the population quantity of the spiders of genus Myrmarachne had no significant change. With the growth of corn, the species number, diversity index, and evenness index of the spiders in S. invicta-invaded and pesticide-treated plot decreased and the predominant indices increased gradually, while the situation in control plot was in adverse. It was concluded that due to the S. invicta invasion in corn field, the community structure of spiders changed.

  5. Microbial diversity determines the invasion of soil by a bacterial pathogen

    PubMed Central

    van Elsas, Jan Dirk; Chiurazzi, Mario; Mallon, Cyrus A.; Elhottovā, Dana; Krištůfek, Václav; Salles, Joana Falcão

    2012-01-01

    Natural ecosystems show variable resistance to invasion by alien species, and this resistance can relate to the species diversity in the system. In soil, microorganisms are key components that determine life support functions, but the functional redundancy in the microbiota of most soils has long been thought to overwhelm microbial diversity–function relationships. We here show an inverse relationship between soil microbial diversity and survival of the invading species Escherichia coli O157:H7, assessed by using the marked derivative strain T. The invader's fate in soil was determined in the presence of (i) differentially constructed culturable bacterial communities, and (ii) microbial communities established using a dilution-to-extinction approach. Both approaches revealed a negative correlation between the diversity of the soil microbiota and survival of the invader. The relationship could be explained by a decrease in the competitive ability of the invader in species-rich vs. species-poor bacterial communities, reflected in the amount of resources used and the rate of their consumption. Soil microbial diversity is a key factor that controls the extent to which bacterial invaders can establish. PMID:22232669

  6. Enhanced Monocyte Response and Decreased Central Memory T Cells in Children with Invasive Staphylococcus aureus Infections

    PubMed Central

    Ardura, Monica I.; Banchereau, Romain; Mejias, Asuncion; Di Pucchio, Tiziana; Glaser, Casey; Allantaz, Florence; Pascual, Virginia; Banchereau, Jacques; Chaussabel, Damien; Ramilo, Octavio

    2009-01-01

    Staphylococcus aureus has emerged as a significant pathogen causing severe invasive disease in otherwise healthy people. Despite considerable advances in understanding the epidemiology, resistance mechanisms, and virulence factors produced by the bacteria, there is limited knowledge of the in vivo host immune response to acute, invasive S. aureus infections. Herein, we report that peripheral blood mononuclear cells from patients with severe S. aureus infections demonstrate a distinctive and robust gene expression profile which is validated in a distinct group of patients and on a different microarray platform. Application of a systems-wide modular analysis framework reveals significant over-expression of innate immunity genes and under-expression of genes related to adaptive immunity. Simultaneous flow cytometry analyses demonstrated marked alterations in immune cell numbers, with decreased central memory CD4 and CD8 T cells and increased numbers of monocytes. CD14+ monocyte numbers significantly correlated with the gene expression levels of genes related to the innate immune response. These results demonstrate the value of applying a systems biology approach that reveals the significant alterations in the components of circulating blood lymphocytes and monocytes in invasive S. aureus infections. PMID:19424507

  7. Inhibition of arachidonic acid metabolism decreases tumor cell invasion and matrix metalloproteinase expression.

    PubMed

    Koontongkaew, Sittichai; Monthanapisut, Paopanga; Saensuk, Theeranuch

    2010-11-01

    Head and neck cancers are known to synthesize arachidonic acid metabolites. Interfering with arachidonic acid metabolism may inhibit growth and invasiveness of cancer cells. In this study we investigate effects of sulindac (the non-selective COX inhibitor), aspirin (the irreversible, preferential COX-1 inhibitor), NS-398 (the selective COX-2 inhibitor), NDGA (nordihydroguaiaretic acid, the selective LOX inhibitor) and ETYA (5,8,11,14-eicosatetraynoic acid, the COX and LOX inhibitor) on cell viability, MMP-2 and MMP-9 activities, and in vitro invasion of cancer cells derived from primary and metastatic head and neck, and colon cancers. The inhibitors of COX and/or LOX could inhibit cell proliferation, MMP activity and invasion in head and neck and colon cancer cells. However, the inhibitory effect was obviously observed in colon cancer cells. Inhibition of arachidonic acid metabolism caused a decrease in cancer cell motility, which partially explained by the inhibition of MMPs. Therefore, COX and LOX pathways play important roles in head and neck cancer cell growth. PMID:20654727

  8. Fire and grazing impacts on plant diversity and alien plant invasions in the southern Sierra Nevada

    USGS Publications Warehouse

    Keeley, Jon E.; Lubin, Daniel; Fotheringham, C.J.

    2003-01-01

    vegetation mosaic in this region places them in proximity to chaparral. The speed at which alien propagules reach a burned site and the speed at which the shrublands return to their former closed-canopy condition determine alien invasion. Frequent burning of this vegetation alters the balance in favor of alien invasion.In the higher-elevation coniferous forests, species diversity was a function of fire severity and time since fire. High-intensity fires create gaps that decrease canopy coverage and increase light levels and nutrients for an ephemeral successional flora. Few species have persistent seed banks, so the time since fire is an important determinant of colonization success. There was a highly significant interaction between fire severity and time since fire for understory cover, species richness, and alien richness and cover. Understory was sparse in the first year after fire, particularly in low-severity burns, and increased substantially several years after fire, particularly on high-severity burns. Both fire severity and time since fire affected alien species richness and dominance. Coniferous forests had about one-third as many alien species as the foothill oak savannas, and fewer than half of the species were shared between these communities. Unburned coniferous forests were largely free of alien species, whereas some burned sites had a significant alien presence, which presents a challenge for fire restoration of these forests.

  9. Cranial diameter pulsations measured by non-invasive ultrasound decrease with tilt

    NASA Technical Reports Server (NTRS)

    Ueno, Toshiaki; Ballard, Richard E.; Macias, Brandon R.; Yost, William T.; Hargens, Alan R.

    2003-01-01

    INTRODUCTION: Intracranial pressure (ICP) may play a significant role in physiological responses to microgravity by contributing to the nausea associated with microgravity exposure. However, effects of altered gravity on ICP in astronauts have not been investigated, primarily due to the invasiveness of currently available techniques. We have developed an ultrasonic device that monitors changes in cranial diameter pulsation non-invasively so that we can evaluate ICP dynamics in astronauts during spaceflight. This study was designed to demonstrate the feasibility of our ultrasound technique under the physiological condition in which ICP dynamics are changed due to altered gravitational force. METHODS: Six healthy volunteers were placed at 60 degrees head-up, 30 degrees headup, supine, and 15 degrees head-down positions for 3 min at each angle. We measured arterial blood pressure (ABP) with a finger pressure cuff, and cranial diameter pulsation with a pulsed phase lock loop device (PPLL). RESULTS: Analysis of covariance demonstrated that amplitudes of cranial diameter pulsations were significantly altered with the angle of tilt (p < 0.001). The 95% confidence interval for linear regression coefficients of the cranial diameter pulsation amplitudes with tilt angle was 0.862 to 0.968. However, ABP amplitudes did not show this relationship. DISCUSSION: Our noninvasive ultrasonic technique reveals that the amplitude of cranial diameter pulsation decreases as a function of tilt angle, suggesting that ICP pulsation follows the same relationship. It is demonstrated that the PPLL device has a sufficient sensitivity to detect changes non-invasively in ICP pulsation caused by altered gravity.

  10. Diversity of dynamics and morphologies of invasive solid tumors

    NASA Astrophysics Data System (ADS)

    Jiao, Yang; Torquato, Salvatore

    2012-03-01

    Complex tumor-host interactions can significantly affect the growth dynamics and morphologies of progressing neoplasms. The growth of a confined solid tumor induces mechanical pressure and deformation of the surrounding microenvironment, which in turn influences tumor growth. In this paper, we generalize a recently developed cellular automaton model for invasive tumor growth in heterogeneous microenvironments [Y. Jiao and S. Torquato, PLoS Comput. Biol. 7, e1002314 (2011)] by incorporating the effects of pressure. Specifically, we explicitly model the pressure exerted on the growing tumor due to the deformation of the microenvironment and its effect on the local tumor-host interface instability. Both noninvasive-proliferative growth and invasive growth with individual cells that detach themselves from the primary tumor and migrate into the surrounding microenvironment are investigated. We find that while noninvasive tumors growing in "soft" homogeneous microenvironments develop almost isotropic shapes, both high pressure and host heterogeneity can strongly enhance malignant behavior, leading to finger-like protrusions of the tumor surface. Moreover, we show that individual invasive cells of an invasive tumor degrade the local extracellular matrix at the tumor-host interface, which diminishes the fingering growth of the primary tumor. The implications of our results for cancer diagnosis, prognosis and therapy are discussed.

  11. Anomalous droughts, not invasion, decrease persistence of native fishes in a desert river.

    PubMed

    Ruhí, Albert; Holmes, Elizabeth E; Rinne, John N; Sabo, John L

    2015-04-01

    Changing climate extremes and invasion by non-native species are two of the most prominent threats to native faunas. Predicting the relationships between global change and native faunas requires a quantitative toolkit that effectively links the timing and magnitude of extreme events to variation in species abundances. Here, we examine how discharge anomalies--unexpected floods and droughts--determine covariation in abundance of native and non-native fish species in a highly variable desert river in Arizona. We quantified stochastic variation in discharge using Fourier analyses on >15,000 daily observations. We subsequently coupled maximum annual spectral anomalies with a 15-year time series of fish abundances (1994-2008), using Multivariate Autoregressive State-Space (MARSS) models. Abiotic drivers (discharge anomalies) were paramount in determining long-term fish abundances, whereas biotic drivers (species interactions) played only a secondary role. As predicted, anomalous droughts reduced the abundances of native species, while floods increased them. However, in contrast to previous studies, we observed that the non-native assemblage was surprisingly unresponsive to extreme events. Biological trait analyses showed that functional uniqueness was higher in native than in non-native fishes. We also found that discharge anomalies influenced diversity patterns at the meta-community level, with nestedness increasing after anomalous droughts due to the differential impairment of native species. Overall, our results advance the notion that discharge variation is key in determining community trajectories in the long term, predicting the persistence of native fauna even in the face of invasion. We suggest this variation, rather than biotic interactions, may commonly underlie covariation between native and non-native faunas, especially in highly variable environments. If droughts become increasingly severe due to climate change, and floods increasingly muted due to

  12. Decreased microbiota diversity associated with urinary tract infection in a trial of bacterial interference

    PubMed Central

    Mapes, Abigail C; Ajami, Nadim J; Petrosino, Joseph F; Ramig, Robert F; Trautner, Barbara W

    2015-01-01

    Background Patients with long-term indwelling catheters are at high risk of catheter-associated urinary tract infection (CAUTI). We hypothesized that colonizing the bladder with a benign E. coli strain (E. coli HU2117, a derivative of E. coli 83972 would prevent CAUTI in older, catheterized adults. Materials and Methods Adults with chronic, indwelling urinary catheters received study catheters that had been pre-coated with E. coli HU2117. We monitored the cultivatable organisms in the bladder for 28 days or until loss of E. coli HU2117. Urine from 4 subjects was collected longitudinally for 16S rRNA gene profiling. Results Eight of the ten subjects (average age 70.9 years) became colonized with E. coli HU2117, with a mean duration of 57.7 days (median: 28.5, range 0-266). All subjects also remained colonized by uropathogens. Five subjects suffered invasive UTI, 3 febrile UTI and 2 urosepsis/bacteremia, all associated with overgrowth of a urinary pathogen. Colonization with E. coli HU2117 did not impact bacterial bladder diversity, but subjects who developed infections had less diverse bladder microbiota. Conclusions Colonization with E. coli HU2117 did not prevent bladder colonization or subsequent invasive disease by uropathogens. Microbial diversity may play a protective role against invasive infection of the catheterized bladder. PMID:26048203

  13. Functional diversity exhibits a diverse relationship with area, even a decreasing one

    PubMed Central

    Karadimou, Elpida K.; Kallimanis, Athanasios S.; Tsiripidis, Ioannis; Dimopoulos, Panayotis

    2016-01-01

    The relationship between species richness and area is one of the few well-established laws in ecology, and one might expect a similar relationship with functional diversity (FD). However, only a few studies investigate the relationship between trait-based FD and area, the Functional Diversity - Area Relationship (FDAR). To examine FDAR, we constructed the species accumulation curve and the corresponding FD curve. We used plant diversity data from nested plots (1–128 m2), recorded on the Volcanic islands of Santorini Archipelagos, Greece. Six multidimensional FD indices were calculated using 26 traits. We identified a typology of FDARs depending on the facet of FD analyzed: (A) strongly positive for indices quantifying the range of functional traits in the community, (B) negative correlation for indices quantifying the evenness in the distribution of abundance in the trait space, (C) no clear pattern for indices reflecting the functional similarity of species and (D) idiosyncratic patterns with area for functional divergence. As area increases, the range of traits observed in the community increases, but the abundance of traits does not increase proportionally and some traits become dominant, implying a reliance on some functions that may be located in either the center or the periphery of the trait space. PMID:27752086

  14. Increased Host Species Diversity and Decreased Prevalence of Sin Nombre Virus

    PubMed Central

    Ruedas, Luis A.

    2009-01-01

    Emerging outbreaks of zoonotic diseases are affecting humans at an alarming rate. Until the ecological factors associated with zoonoses are better understood, disease emergence will continue. For Lyme disease, disease suppression has been demonstrated by a dilution effect, whereby increasing species diversity decreases disease prevalence in host populations. To test the dilution effect in another disease, we examined 17 ecological variables associated with prevalence of the directly transmitted Sin Nombre virus (genus Hantavirus, etiologic agent of hantavirus pulmonary syndrome) in its wildlife host, the deer mouse (Peromyscus maniculatus). Only species diversity was statistically linked to infection prevalence: as species diversity decreased, infection prevalence increased. The increase was moderate, but prevalence increased exponentially at low levels of diversity, a phenomenon described as zoonotic release. The results suggest that species diversity affects disease emergence. PMID:19624913

  15. Multiple introductions boosted genetic diversity in the invasive range of black cherry (Prunus serotina; Rosaceae)

    PubMed Central

    Pairon, Marie; Petitpierre, Blaise; Campbell, Michael; Guisan, Antoine; Broennimann, Olivier; Baret, Philippe V.; Jacquemart, Anne-Laure; Besnard, Guillaume

    2010-01-01

    Background and Aims Black cherry (Prunus serotina) is a North American tree that is rapidly invading European forests. This species was introduced first as an ornamental plant then it was massively planted by foresters in many countries but its origins and the process of invasion remain poorly documented. Based on a genetic survey of both native and invasive ranges, the invasion history of black cherry was investigated by identifying putative source populations and then assessing the importance of multiple introductions on the maintenance of gene diversity. Methods Genetic variability and structure of 23 populations from the invasive range and 22 populations from the native range were analysed using eight nuclear microsatellite loci and five chloroplast DNA regions. Key Results Chloroplast DNA diversity suggests there were multiple introductions from a single geographic region (the north-eastern United States). A low reduction of genetic diversity was observed in the invasive range for both nuclear and plastid genomes. High propagule pressure including both the size and number of introductions shaped the genetic structure in Europe and boosted genetic diversity. Populations from Denmark, The Netherlands, Belgium and Germany showed high genetic diversity and low differentiation among populations, supporting the hypothesis that numerous introduction events, including multiple individuals and exchanges between sites, have taken place during two centuries of plantation. Conclusions This study postulates that the invasive black cherry has originated from east of the Appalachian Mountains (mainly the Allegheny plateau) and its invasiveness in north-western Europe is mainly due to multiple introductions containing high numbers of individuals. PMID:20400456

  16. Disruption of foraging by a dominant invasive species to decrease its competitive ability.

    PubMed

    Westermann, Fabian Ludwig; Suckling, David Maxwell; Lester, Philip John

    2014-01-01

    Invasive species are a major threat to biodiversity when dominant within their newly established habitat. The globally distributed Argentine ant Linepithema humile has been reported to break the trade-off between interference and exploitative competition, achieve high population densities, and overpower nests of many endemic ant species. We have used the sensitivity of the Argentine ant to the synthetic trail pheromone (Z)-9-hexadecanal to investigate species interactions for the first time. We predicted that disrupting Argentine ant trail following behaviour would reduce their competitive ability and create an opportunity for three other resident species to increase their foraging success. Argentine ant success in the control was reduced with increasing pheromone concentration, as predicted, but interactions varied among competing resident species. These behavioural variations provide an explanation for observed differences in foraging success of the competing resident species and how much each of these individual competitors can increase their foraging if the competitive ability of the dominant invader is decreased. The mechanism for the observed increase in resource acquisition of resident species appears to be a decrease in aggressive behaviour displayed by the Argentine ant, which may create an opportunity for other resident species to forage more successfully. Our demonstration of species interactions with trail pheromone disruption is the first known case of reduced dominance under a pheromone treatment in ants.

  17. Disruption of Foraging by a Dominant Invasive Species to Decrease Its Competitive Ability

    PubMed Central

    Westermann, Fabian Ludwig; Suckling, David Maxwell; Lester, Philip John

    2014-01-01

    Invasive species are a major threat to biodiversity when dominant within their newly established habitat. The globally distributed Argentine ant Linepithema humile has been reported to break the trade-off between interference and exploitative competition, achieve high population densities, and overpower nests of many endemic ant species. We have used the sensitivity of the Argentine ant to the synthetic trail pheromone (Z)-9-hexadecanal to investigate species interactions for the first time. We predicted that disrupting Argentine ant trail following behaviour would reduce their competitive ability and create an opportunity for three other resident species to increase their foraging success. Argentine ant success in the control was reduced with increasing pheromone concentration, as predicted, but interactions varied among competing resident species. These behavioural variations provide an explanation for observed differences in foraging success of the competing resident species and how much each of these individual competitors can increase their foraging if the competitive ability of the dominant invader is decreased. The mechanism for the observed increase in resource acquisition of resident species appears to be a decrease in aggressive behaviour displayed by the Argentine ant, which may create an opportunity for other resident species to forage more successfully. Our demonstration of species interactions with trail pheromone disruption is the first known case of reduced dominance under a pheromone treatment in ants. PMID:24594633

  18. The role of propagule pressure, genetic diversity and microsite availability for Senecio vernalis invasion.

    PubMed

    Erfmeier, Alexandra; Hantsch, Lydia; Bruelheide, Helge

    2013-01-01

    Genetic diversity is supposed to support the colonization success of expanding species, in particular in situations where microsite availability is constrained. Addressing the role of genetic diversity in plant invasion experimentally requires its manipulation independent of propagule pressure. To assess the relative importance of these components for the invasion of Senecio vernalis, we created propagule mixtures of four levels of genotype diversity by combining seeds across remote populations, across proximate populations, within single populations and within seed families. In a first container experiment with constant Festuca rupicola density as matrix, genotype diversity was crossed with three levels of seed density. In a second experiment, we tested for effects of establishment limitation and genotype diversity by manipulating Festuca densities. Increasing genetic diversity had no effects on abundance and biomass of S. vernalis but positively affected the proportion of large individuals to small individuals. Mixtures composed from proximate populations had a significantly higher proportion of large individuals than mixtures composed from within seed families only. High propagule pressure increased emergence and establishment of S. vernalis but had no effect on individual growth performance. Establishment was favoured in containers with Festuca, but performance of surviving seedlings was higher in open soil treatments. For S. vernalis invasion, we found a shift in driving factors from density dependence to effects of genetic diversity across life stages. While initial abundance was mostly linked to the amount of seed input, genetic diversity, in contrast, affected later stages of colonization probably via sampling effects and seemed to contribute to filtering the genotypes that finally grew up. In consequence, when disentangling the mechanistic relationships of genetic diversity, seed density and microsite limitation in colonization of invasive plants, a clear

  19. The role of propagule pressure, genetic diversity and microsite availability for Senecio vernalis invasion.

    PubMed

    Erfmeier, Alexandra; Hantsch, Lydia; Bruelheide, Helge

    2013-01-01

    Genetic diversity is supposed to support the colonization success of expanding species, in particular in situations where microsite availability is constrained. Addressing the role of genetic diversity in plant invasion experimentally requires its manipulation independent of propagule pressure. To assess the relative importance of these components for the invasion of Senecio vernalis, we created propagule mixtures of four levels of genotype diversity by combining seeds across remote populations, across proximate populations, within single populations and within seed families. In a first container experiment with constant Festuca rupicola density as matrix, genotype diversity was crossed with three levels of seed density. In a second experiment, we tested for effects of establishment limitation and genotype diversity by manipulating Festuca densities. Increasing genetic diversity had no effects on abundance and biomass of S. vernalis but positively affected the proportion of large individuals to small individuals. Mixtures composed from proximate populations had a significantly higher proportion of large individuals than mixtures composed from within seed families only. High propagule pressure increased emergence and establishment of S. vernalis but had no effect on individual growth performance. Establishment was favoured in containers with Festuca, but performance of surviving seedlings was higher in open soil treatments. For S. vernalis invasion, we found a shift in driving factors from density dependence to effects of genetic diversity across life stages. While initial abundance was mostly linked to the amount of seed input, genetic diversity, in contrast, affected later stages of colonization probably via sampling effects and seemed to contribute to filtering the genotypes that finally grew up. In consequence, when disentangling the mechanistic relationships of genetic diversity, seed density and microsite limitation in colonization of invasive plants, a clear

  20. RNAi knockdown of Hop (Hsp70/Hsp90 organising protein) decreases invasion via MMP-2 down regulation.

    PubMed

    Walsh, Naomi; Larkin, AnneMarie; Swan, Niall; Conlon, Kevin; Dowling, Paul; McDermott, Ray; Clynes, Martin

    2011-07-28

    We previously identified Hop as over expressed in invasive pancreatic cancer cell lines and malignant tissues of pancreatic cancer patients, suggesting an important role for Hop in the biology of invasive pancreatic cancer. Hop is a co-chaperone protein that binds to both Hsp70/Hsp90. We hypothesised that by targeting Hop, signalling pathways modulating invasion and client protein stabilisation involving Hsp90-dependent complexes may be altered. In this study, we show that Hop knockdown by small interfering (si)RNA reduces the invasion of pancreatic cancer cells, resulting in decreased expression of the downstream target gene, matrix metalloproteinases-2 (MMP-2). Hop in conditioned media co-immunoprecipitates with MMP-2, implicating a possible extracellular function for Hop. Knockdown of Hop expression also reduced expression levels of Hsp90 client proteins, HER2, Bcr-Abl, c-MET and v-Src. Furthermore, Hop is strongly expressed in high grade PanINs compared to lower PanIN grades, displaying differential localisation in invasive ductal pancreatic cancer, indicating that the localisation of Hop is an important factor in pancreatic tumours. Our data suggests that the attenuation of Hop expression inactivates key signal transduction proteins which may decrease the invasiveness of pancreatic cancer cells possibly through the modulation of Hsp90 activity. Therefore, targeting Hop in pancreatic cancer may constitute a viable strategy for targeted cancer therapy.

  1. Landscape corridors can increase invasion by an exotic species and reduce diversity of native species.

    SciTech Connect

    Resasco, Julian; et al,

    2014-04-01

    Abstract. Landscape corridors are commonly used to mitigate negative effects of habitat fragmentation, but concerns persist that they may facilitate the spread of invasive species. In a replicated landscape experiment of open habitat, we measured effects of corridors on the invasive fire ant, Solenopsis invicta, and native ants. Fire ants have two social forms: polygyne, which tend to disperse poorly but establish at high densities, and monogyne, which disperse widely but establish at lower densities. In landscapes dominated by polygyne fire ants, fire ant abundance was higher and native ant diversity was lower in habitat patches connected by corridors than in unconnected patches. Conversely, in landscapes dominated by monogyne fire ants, connectivity had no influence on fire ant abundance and native ant diversity. Polygyne fire ants dominated recently created landscapes, suggesting that these corridor effects may be transient. Our results suggest that corridors can facilitate invasion and they highlight the importance of considering species’ traits when assessing corridor utility.

  2. Eco-evolutionary community dynamics: covariation between diversity and invasibility across temperature gradients.

    PubMed

    Stegen, James C; Enquist, Brian J; Ferrière, Régis

    2012-10-01

    Understanding biodiversity gradients is a long-standing challenge, and progress requires theory unifying ecology and evolution. Here, we unify concepts related to the speed of evolution, the influence of species richness on diversification, and niche-based coexistence. We focus on the dynamics, through evolutionary time, of community invasibility and species richness across a broad thermal gradient. In our framework, the evolution of body size influences the ecological structure and dynamics of a trophic network, and organismal metabolism ties temperature to eco-evolutionary processes. The framework distinguishes ecological invasibility (governed by ecological interactions) from evolutionary invasibility (governed by local ecology and constraints imposed by small phenotypic effects of mutation). The model yields four primary predictions: (1) ecological invasibility declines through time and with increasing temperature; (2) average evolutionary invasibility across communities increases and then decreases through time as the richness-temperature gradient flattens; (3) in the early stages of diversification, richness and evolutionary invasibility both increase with increasing temperature; and (4) at equilibrium, richness does not vary with temperature, yet evolutionary invasibility decreases with increasing temperature. These predictions emerge from the "evolutionary-speed" hypothesis, which attempts to account for latitudinal species richness gradients by invoking faster biological rates in warmer, tropical regions. The model contrasts with predictions from other richness-gradient hypotheses, such as "niche conservatism" and "species energy." Empirically testing our model's predictions should help distinguish among these hypotheses. PMID:22976016

  3. Decreases in ammonia volatilization in response to greater plant diversity in microcosms of constructed wetlands

    NASA Astrophysics Data System (ADS)

    Luo, Bin; Ge, Ying; Han, Wenjuan; Fan, Xing; Ren, Yuan; Du, Yuanyuan; Shi, Mengmeng; Chang, Jie

    2016-10-01

    Ammonia volatilization from wastewaters with a high concentration of ammonium is a serious environmental and health problem. Constructed wetlands (CWs) are widely used for treating wastewater, and plant diversity clearly improves some functions of ecosystem such as nitrogen removal. However, whether plant diversity can affect ammonia volatilization from wastewater is still unknown. In this study, we conducted a microcosm experiment with different plant diversity treatments using four plant species. Results showed that, (1) ammonia volatilization decreased with increasing plant species richness; (2) ammonia volatilization from systems containing Rumex japonicus was lower than other systems; and (3) ammonia volatilization was affected more by species composition than species richness. This paper is the first to report that ammonia volatilization is reduced by plant diversity, and that some plant species combinations are important to reduce ammonia volatilization from CWs when treating wastewater.

  4. An invasive non-native mammal population conserves genetic diversity lost from its native range.

    PubMed

    Veale, A J; Holland, O J; McDonald, R A; Clout, M N; Gleeson, D M

    2015-05-01

    Invasive, non-native species are one of the major causes of global biodiversity loss. Although they are, by definition, successful in their non-native range, their populations generally show major reductions in their genetic diversity during the demographic bottleneck they experience during colonization. By investigating the mitochondrial genetic diversity of an invasive non-native species, the stoat Mustela erminea, in New Zealand and comparing it to diversity in the species' native range in Great Britain, we reveal the opposite effect. We demonstrate that the New Zealand stoat population contains four mitochondrial haplotypes that have not been found in the native range. Stoats in Britain rely heavily on introduced rabbits Oryctolagus cuniculus as their primary prey and were introduced to New Zealand in a misguided attempt at biological control of rabbits, which had also been introduced there. While invasive stoats have since decimated the New Zealand avifauna, native stoat populations were themselves decimated by the introduction to Britain of Myxoma virus as a control measure for rabbits. We highlight the irony that while introduced species (rabbits) and subsequent biocontrol (myxomatosis) have caused population crashes of native stoats, invasive stoats in New Zealand, which were also introduced for biological control, now contain more genetic haplotypes than their most likely native source. PMID:25655531

  5. Overexpression of Csk-binding protein decreases growth, invasion, and migration of esophageal carcinoma cells by controlling Src activation

    PubMed Central

    Zhou, Dong; Dong, Peng; Li, Yu-Min; Guo, Fa-Cai; Zhang, An-Ping; Song, Run-Ze; Zhang, Ya-Min; Li, Zhi-Yong; Yuan, Dong; Yang, Chuan

    2015-01-01

    AIM: To investigate the mechanisms by which Csk-binding protein (CBP) inhibits tumor progression in esophageal carcinoma. METHODS: A CBP overexpressing esophageal carcinoma cell line (TE-1) was established. The growth, invasion, and migration of CBP-TE-1 cells, as well as the expression of Src were then determined and compared with those in normal TE-1 cells. RESULTS: The expression of Src was decreased by the overexpression of CBP in TE-1 cells. The growth, invasion, and migration of TE-1 cells were decreased by the overexpression of CBP. CONCLUSION: This study indicates that CBP may decrease the metastasis of esophageal carcinoma by inhibiting the activation of Src. CBP may be a potential tumor suppressor and targeting the CBP gene may be an alternative strategy for the development of therapies for esophageal carcinoma. PMID:25684946

  6. "Nested" cryptic diversity in a widespread marine ecosystem engineer: a challenge for detecting biological invasions

    PubMed Central

    2011-01-01

    Background Ecosystem engineers facilitate habitat formation and enhance biodiversity, but when they become invasive, they present a critical threat to native communities because they can drastically alter the receiving habitat. Management of such species thus needs to be a priority, but the poorly resolved taxonomy of many ecosystem engineers represents a major obstacle to correctly identifying them as being either native or introduced. We address this dilemma by studying the sea squirt Pyura stolonifera, an important ecosystem engineer that dominates coastal communities particularly in the southern hemisphere. Using DNA sequence data from four independently evolving loci, we aimed to determine levels of cryptic diversity, the invasive or native status of each regional population, and the most appropriate sampling design for identifying the geographic ranges of each evolutionary unit. Results Extensive sampling in Africa, Australasia and South America revealed the existence of "nested" levels of cryptic diversity, in which at least five distinct species can be further subdivided into smaller-scale genetic lineages. The ranges of several evolutionary units are limited by well-documented biogeographic disjunctions. Evidence for both cryptic native diversity and the existence of invasive populations allows us to considerably refine our view of the native versus introduced status of the evolutionary units within Pyura stolonifera in the different coastal communities they dominate. Conclusions This study illustrates the degree of taxonomic complexity that can exist within widespread species for which there is little taxonomic expertise, and it highlights the challenges involved in distinguishing between indigenous and introduced populations. The fact that multiple genetic lineages can be native to a single geographic region indicates that it is imperative to obtain samples from as many different habitat types and biotic zones as possible when attempting to identify the

  7. Reduced Genetic Diversity and Increased Structure in American Mink on the Swedish Coast following Invasive Species Control.

    PubMed

    Zalewski, Andrzej; Zalewska, Hanna; Lunneryd, Sven-Gunnar; André, Carl; Mikusiński, Grzegorz

    2016-01-01

    Eradication and population reductions are often used to mitigate the negative impacts of non-native invasive species on native biodiversity. However, monitoring the effectiveness of non-native species control programmes is necessary to evaluate the efficacy of these measures. Genetic monitoring could provide valuable insights into temporal changes in demographic, ecological, and evolutionary processes in invasive populations being subject to control programmes. Such programmes should cause a decrease in effective population size and/or in genetic diversity of the targeted non-native species and an increase in population genetic structuring over time. We used microsatellite DNA data from American mink (Neovison vison) to determine whether the removal of this predator on the Koster Islands archipelago and the nearby Swedish mainland affected genetic variation over six consecutive years of mink culling by trappers as part of a population control programme. We found that on Koster Islands allelic richness decreased (from on average 4.53 to 3.55), genetic structuring increased, and effective population size did not change. In contrast, the mink population from the Swedish coast showed no changes in genetic diversity or structure, suggesting the stability of this population over 6 years of culling. Effective population size did not change over time but was higher on the coast than on the islands across all years. Migration rates from the islands to the coast were almost two times higher than from the coast to the islands. Most migrants leaving the coast were localised on the southern edge of the archipelago, as expected from the direction of the sea current between the two sites. Genetic monitoring provided valuable information on temporal changes in the population of American mink suggesting that this approach can be used to evaluate and improve control programmes of invasive vertebrates. PMID:27333328

  8. Reduced Genetic Diversity and Increased Structure in American Mink on the Swedish Coast following Invasive Species Control.

    PubMed

    Zalewski, Andrzej; Zalewska, Hanna; Lunneryd, Sven-Gunnar; André, Carl; Mikusiński, Grzegorz

    2016-01-01

    Eradication and population reductions are often used to mitigate the negative impacts of non-native invasive species on native biodiversity. However, monitoring the effectiveness of non-native species control programmes is necessary to evaluate the efficacy of these measures. Genetic monitoring could provide valuable insights into temporal changes in demographic, ecological, and evolutionary processes in invasive populations being subject to control programmes. Such programmes should cause a decrease in effective population size and/or in genetic diversity of the targeted non-native species and an increase in population genetic structuring over time. We used microsatellite DNA data from American mink (Neovison vison) to determine whether the removal of this predator on the Koster Islands archipelago and the nearby Swedish mainland affected genetic variation over six consecutive years of mink culling by trappers as part of a population control programme. We found that on Koster Islands allelic richness decreased (from on average 4.53 to 3.55), genetic structuring increased, and effective population size did not change. In contrast, the mink population from the Swedish coast showed no changes in genetic diversity or structure, suggesting the stability of this population over 6 years of culling. Effective population size did not change over time but was higher on the coast than on the islands across all years. Migration rates from the islands to the coast were almost two times higher than from the coast to the islands. Most migrants leaving the coast were localised on the southern edge of the archipelago, as expected from the direction of the sea current between the two sites. Genetic monitoring provided valuable information on temporal changes in the population of American mink suggesting that this approach can be used to evaluate and improve control programmes of invasive vertebrates.

  9. Reduced Genetic Diversity and Increased Structure in American Mink on the Swedish Coast following Invasive Species Control

    PubMed Central

    Zalewska, Hanna; Lunneryd, Sven-Gunnar; André, Carl; Mikusiński, Grzegorz

    2016-01-01

    Eradication and population reductions are often used to mitigate the negative impacts of non-native invasive species on native biodiversity. However, monitoring the effectiveness of non-native species control programmes is necessary to evaluate the efficacy of these measures. Genetic monitoring could provide valuable insights into temporal changes in demographic, ecological, and evolutionary processes in invasive populations being subject to control programmes. Such programmes should cause a decrease in effective population size and/or in genetic diversity of the targeted non-native species and an increase in population genetic structuring over time. We used microsatellite DNA data from American mink (Neovison vison) to determine whether the removal of this predator on the Koster Islands archipelago and the nearby Swedish mainland affected genetic variation over six consecutive years of mink culling by trappers as part of a population control programme. We found that on Koster Islands allelic richness decreased (from on average 4.53 to 3.55), genetic structuring increased, and effective population size did not change. In contrast, the mink population from the Swedish coast showed no changes in genetic diversity or structure, suggesting the stability of this population over 6 years of culling. Effective population size did not change over time but was higher on the coast than on the islands across all years. Migration rates from the islands to the coast were almost two times higher than from the coast to the islands. Most migrants leaving the coast were localised on the southern edge of the archipelago, as expected from the direction of the sea current between the two sites. Genetic monitoring provided valuable information on temporal changes in the population of American mink suggesting that this approach can be used to evaluate and improve control programmes of invasive vertebrates. PMID:27333328

  10. 17β-Estradiol treatment inhibits breast cell proliferation, migration and invasion by decreasing MALAT-1 RNA level

    SciTech Connect

    Zhao, Ziyi; Chen, Changjin; Liu, Yu; Wu, Chuanfang

    2014-03-07

    Highlights: • E2 affects not only estrogen-receptor α positive breast cells but also negative ones. • 100 nM E2 treatment affects breast cells proliferation, migration. • 100 nM E2 treatment functions in an estrogen-receptor α-independent way. • E2 treatment decreases MALAT-1 RNA level by post-transcriptional regulation. - Abstract: Breast cancer cells, which express estrogen receptor α (ERα), respond to estrogen in a concentration dependent fashion, resulting in proliferation or apoptosis. But breast cancer cells without ERα show no effect on low concentration of estrogen treatment. Proliferation, migration and invasion of MCF10a, MCF7 and MB231 cells treated with low (1 nM) or high (100 nM) dose of 17β-Estradiol (E2) was performed. We identified the effects of E2 on these breast cell lines, and looked for the difference in the presence and absence of ERα. Specifically, we looked for the changes of long non-coding RNA metastasis associated lung adenocarcinoma transcript 1 (MALAT-1), which is found extensively and highly expressed in several kinds of tumor cells, including breast carcinoma. It was observed that proliferation, migration and invasion of breast cells were greatly affected by high concentration E2 treatment and were not affected by low concentration E2 treatment in an ERα independent way. We found that the high concentration E2 treatment largely decreased MALAT-1 RNA level. Interestingly, MALAT-1 decreasing by knocking down showed similar effects on proliferation, migration and invasion. E2 treatment affects breast tumor or non-tumor cells proliferation, migration and invasion in an ERα -independent, but a dose-dependent way by decreasing the MALAT-1 RNA level.

  11. Diversity of burial rates in convergent settings decreased as Earth aged.

    PubMed

    Nicoli, Gautier; Moyen, Jean-François; Stevens, Gary

    2016-01-01

    The evolution and the growth of the continental crust is inextricably linked to the evolution of Earth's geodynamic processes. The detrital zircon record within the continental crust, as well as the isotopic composition of this crust, indicates that the amount of juvenile felsic material decreased with time and that in geologically recent times, the generation of new crust is balanced by recycling of the crust back into the mantle within subduction zones. However it cannot always have been so; yet the nature of the crust and the processes of crustal reworking in the Precambrian Earth are not well constrained. Here we use both detrital zircon ages and metamorphic pressure-temperature-time (P-T-t) information from metasedimentary units deposited in proposed convergent settings from Archaean, Proterozoic and Phanerozoic terrains to characterize the evolution of minimum estimates of burial rate (km.Ma(-1)) as a function of the age of the rocks. The demonstrated decrease in burial rate correlates positively with a progressive decrease in the production of juvenile felsic crust in the Archaean and Proterozoic. Burial rates are also more diverse in the Archaean than in modern times. We interpret these features to reflect a progressive decrease in the diversity of tectonic processes from Archaean to present, coupled with the emergence of the uniquely Phanerozoic modern-style collision. PMID:27216133

  12. Diversity of burial rates in convergent settings decreased as Earth aged.

    PubMed

    Nicoli, Gautier; Moyen, Jean-François; Stevens, Gary

    2016-05-24

    The evolution and the growth of the continental crust is inextricably linked to the evolution of Earth's geodynamic processes. The detrital zircon record within the continental crust, as well as the isotopic composition of this crust, indicates that the amount of juvenile felsic material decreased with time and that in geologically recent times, the generation of new crust is balanced by recycling of the crust back into the mantle within subduction zones. However it cannot always have been so; yet the nature of the crust and the processes of crustal reworking in the Precambrian Earth are not well constrained. Here we use both detrital zircon ages and metamorphic pressure-temperature-time (P-T-t) information from metasedimentary units deposited in proposed convergent settings from Archaean, Proterozoic and Phanerozoic terrains to characterize the evolution of minimum estimates of burial rate (km.Ma(-1)) as a function of the age of the rocks. The demonstrated decrease in burial rate correlates positively with a progressive decrease in the production of juvenile felsic crust in the Archaean and Proterozoic. Burial rates are also more diverse in the Archaean than in modern times. We interpret these features to reflect a progressive decrease in the diversity of tectonic processes from Archaean to present, coupled with the emergence of the uniquely Phanerozoic modern-style collision.

  13. Diversity of burial rates in convergent settings decreased as Earth aged

    PubMed Central

    Nicoli, Gautier; Moyen, Jean-François; Stevens, Gary

    2016-01-01

    The evolution and the growth of the continental crust is inextricably linked to the evolution of Earth’s geodynamic processes. The detrital zircon record within the continental crust, as well as the isotopic composition of this crust, indicates that the amount of juvenile felsic material decreased with time and that in geologically recent times, the generation of new crust is balanced by recycling of the crust back into the mantle within subduction zones. However it cannot always have been so; yet the nature of the crust and the processes of crustal reworking in the Precambrian Earth are not well constrained. Here we use both detrital zircon ages and metamorphic pressure-temperature-time (P-T-t) information from metasedimentary units deposited in proposed convergent settings from Archaean, Proterozoic and Phanerozoic terrains to characterize the evolution of minimum estimates of burial rate (km.Ma−1) as a function of the age of the rocks. The demonstrated decrease in burial rate correlates positively with a progressive decrease in the production of juvenile felsic crust in the Archaean and Proterozoic. Burial rates are also more diverse in the Archaean than in modern times. We interpret these features to reflect a progressive decrease in the diversity of tectonic processes from Archaean to present, coupled with the emergence of the uniquely Phanerozoic modern-style collision. PMID:27216133

  14. Diversity of burial rates in convergent settings decreased as Earth aged

    NASA Astrophysics Data System (ADS)

    Nicoli, Gautier; Moyen, Jean-François; Stevens, Gary

    2016-05-01

    The evolution and the growth of the continental crust is inextricably linked to the evolution of Earth’s geodynamic processes. The detrital zircon record within the continental crust, as well as the isotopic composition of this crust, indicates that the amount of juvenile felsic material decreased with time and that in geologically recent times, the generation of new crust is balanced by recycling of the crust back into the mantle within subduction zones. However it cannot always have been so; yet the nature of the crust and the processes of crustal reworking in the Precambrian Earth are not well constrained. Here we use both detrital zircon ages and metamorphic pressure-temperature-time (P-T-t) information from metasedimentary units deposited in proposed convergent settings from Archaean, Proterozoic and Phanerozoic terrains to characterize the evolution of minimum estimates of burial rate (km.Ma‑1) as a function of the age of the rocks. The demonstrated decrease in burial rate correlates positively with a progressive decrease in the production of juvenile felsic crust in the Archaean and Proterozoic. Burial rates are also more diverse in the Archaean than in modern times. We interpret these features to reflect a progressive decrease in the diversity of tectonic processes from Archaean to present, coupled with the emergence of the uniquely Phanerozoic modern-style collision.

  15. Diversity of burial rates in convergent settings decreased as Earth aged

    NASA Astrophysics Data System (ADS)

    Nicoli, Gautier; Moyen, Jean-François; Stevens, Gary

    2016-05-01

    The evolution and the growth of the continental crust is inextricably linked to the evolution of Earth’s geodynamic processes. The detrital zircon record within the continental crust, as well as the isotopic composition of this crust, indicates that the amount of juvenile felsic material decreased with time and that in geologically recent times, the generation of new crust is balanced by recycling of the crust back into the mantle within subduction zones. However it cannot always have been so; yet the nature of the crust and the processes of crustal reworking in the Precambrian Earth are not well constrained. Here we use both detrital zircon ages and metamorphic pressure-temperature-time (P-T-t) information from metasedimentary units deposited in proposed convergent settings from Archaean, Proterozoic and Phanerozoic terrains to characterize the evolution of minimum estimates of burial rate (km.Ma-1) as a function of the age of the rocks. The demonstrated decrease in burial rate correlates positively with a progressive decrease in the production of juvenile felsic crust in the Archaean and Proterozoic. Burial rates are also more diverse in the Archaean than in modern times. We interpret these features to reflect a progressive decrease in the diversity of tectonic processes from Archaean to present, coupled with the emergence of the uniquely Phanerozoic modern-style collision.

  16. Non-native grass invasion associated with increases in insect diversity in temperate forest understory

    NASA Astrophysics Data System (ADS)

    Metcalf, Judith L.; Emery, Sarah M.

    2015-11-01

    Invasive plants can alter the structure and function of plant communities to such a degree that they can also have significant impacts on the insect communities. Because insects play an important role in many ecosystems, changes in these communities could have important implications, beyond their biodiversity value, for ecosystem function and diversity at other trophic levels. Microstegium vimineum is an annual C4 grass that is invasive in many eastern North American deciduous forests. Because this grass plays an important role in determining the plant community structure in the understory of these forests, it also has the potential to significantly alter understory insect communities. In this study we evaluated the relationship between M. vimineum and understory insect communities in a forest reserve in Kentucky, USA. Total insect abundance, richness and diversity showed a positive association with M. vimineum presence. Trophic analysis showed significantly higher abundances of herbivores where M. vimineum was present. Forb abundance, which serves as the primary food source for herbivorous insects in this system, was lower in sites invaded with M. vimineum. Invasion by this non-native was also associated with significant increases in aboveground plant biomass which was nearly 50% greater in invaded sites. These results indicate that the understory insect community may be responding to increased biomass rather than the loss of native forb food resources, which contradicts other studies that have examined relationships between M. vimineum invasion and insects. Our results provide evidence that invasive plants can provide benefits for other trophic levels, even when native plant biodiversity is lost.

  17. Differentiating between effects of invasion and diversity: impacts of aboveground plant communities on belowground fungal communities.

    PubMed

    Kivlin, Stephanie N; Hawkes, Christine V

    2011-01-01

    Exotic plant species can affect soil microbial communities with the potential for community and ecosystem feedbacks. Yet, separating the effects of exotics from confounded changes in plant community diversity still remains a challenge. We focused on how plant diversity and native or exotic life history affected root fungi because of their significant roles in community and ecosystem processes. Specifically, we examined how fungi colonizing plant roots were affected by plant richness (one, two or four species) replicated across a range of plant community mixtures (natives, exotics, native-exotic mixtures). Fungal biomass inside roots was affected independently by plant richness and mixture, while root fungal community composition was affected only by plant richness. Extraradical networks also increased in size with plant richness. By contrast, plant biomass was a function of plant mixture, with natives consistently smaller than exotics and native-exotic mixtures intermediate. Plant invasions may have an impact on the belowground community primarily through their effects on diversity, at least in the short-term. Disentangling the effects of diversity and invasion on belowground microbial communities can help us to understand both the controllers of belowground resilience and mechanisms of successful colonization and spread of exotic plants.

  18. Effects of the brown anole invasion and betelnut palm planting on arthropod diversity in southern Taiwan.

    PubMed

    Huang, Shao-Chang; Norval, Gerrut; Wei, Chia-Shian; Tso, I-Min

    2008-11-01

    The brown anole ( Anolis sagrei ) occurs naturally in various localities in Central America, and an exotic invasive population was first reported in Sheishan District, Chiayi County, Taiwan, in 2000. Previous studies showed that following the invasion of A. sagrei , the diversity and abundance of local terrestrial arthropods, such as orb spiders and arboreal insects, were severely affected. In this study, we assessed the impact of A. sagrei on arthropod diversity in Taiwan by comparing spider and insect diversities among betelnut palm plantations, in which this lizard species was either present or absent, and a secondary forest. In addition, enclosures were established in which the density of A. sagrei was manipulated to investigate the effect of this predator on spiders. The results of a lizard stomach content analysis showed that spiders comprised 7% and insects 90% of the prey consumed. Among the insects consumed by A. sagrei , more than 50% were ants. The abundances of the major arthropod prey of A. sagrei , such as jumping spiders and hymenopterans, in the lizard-present sites were much lower than in the lizard-removed sites. The enclosure experiments also showed that predation by the lizards significantly reduced the abundance of jumping spiders. All these results indicated that the introduced lizard greatly affected the diversity and abundance of terrestrial arthropods in agricultural areas in southern Taiwan. PMID:19267623

  19. Decreased Nucleotide and Expression Diversity and Modified Coexpression Patterns Characterize Domestication in the Common Bean.

    PubMed

    Bellucci, Elisa; Bitocchi, Elena; Ferrarini, Alberto; Benazzo, Andrea; Biagetti, Eleonora; Klie, Sebastian; Minio, Andrea; Rau, Domenico; Rodriguez, Monica; Panziera, Alex; Venturini, Luca; Attene, Giovanna; Albertini, Emidio; Jackson, Scott A; Nanni, Laura; Fernie, Alisdair R; Nikoloski, Zoran; Bertorelle, Giorgio; Delledonne, Massimo; Papa, Roberto

    2014-05-21

    Using RNA sequencing technology and de novo transcriptome assembly, we compared representative sets of wild and domesticated accessions of common bean (Phaseolus vulgaris) from Mesoamerica. RNA was extracted at the first true-leaf stage, and de novo assembly was used to develop a reference transcriptome; the final data set consists of ∼190,000 single nucleotide polymorphisms from 27,243 contigs in expressed genomic regions. A drastic reduction in nucleotide diversity (∼60%) is evident for the domesticated form, compared with the wild form, and almost 50% of the contigs that are polymorphic were brought to fixation by domestication. In parallel, the effects of domestication decreased the diversity of gene expression (18%). While the coexpression networks for the wild and domesticated accessions demonstrate similar seminal network properties, they show distinct community structures that are enriched for different molecular functions. After simulating the demographic dynamics during domestication, we found that 9% of the genes were actively selected during domestication. We also show that selection induced a further reduction in the diversity of gene expression (26%) and was associated with 5-fold enrichment of differentially expressed genes. While there is substantial evidence of positive selection associated with domestication, in a few cases, this selection has increased the nucleotide diversity in the domesticated pool at target loci associated with abiotic stress responses, flowering time, and morphology.

  20. Increasing land-use intensity decreases floral colour diversity of plant communities in temperate grasslands.

    PubMed

    Binkenstein, Julia; Renoult, Julien P; Schaefer, H Martin

    2013-10-01

    To preserve biodiversity and ecosystem functions in a globally changing world it is crucial to understand the effect of land use on ecosystem processes such as pollination. Floral colouration is known to be central in plant-pollinator interactions. To date, it is still unknown whether land use affects the colouration of flowering plant communities. To assess the effect of land use on the diversity and composition of flower colours in temperate grasslands, we collected data on the number of flowering plant species, blossom cover and flower reflectance spectra from 69 plant communities in two German regions, Schwäbische Alb (SA) and Hainich-Dün (HD). We analysed reflectance data of flower colours as they are perceived by honeybees and studied floral colour diversity based upon spectral loci of each flowering plant species in the Maxwell triangle. Before the first mowing, flower colour diversity decreased with increasing land-use intensity in SA, accompanied by a shift of mean flower colours of communities towards an increasing proportion of white blossom cover in both regions. By changing colour characteristics of grasslands, we suggest that increasing land-use intensity can affect the flower visitor fauna in terms of visitor behaviour and diversity. These changes may in turn influence plant reproduction in grassland plant communities. Our results indicate that land use is likely to affect communication processes between plants and flower visitors by altering flower colour traits.

  1. Isoliquiritigenin inhibits migration and invasion of prostate cancer cells: possible mediation by decreased JNK/AP-1 signaling.

    PubMed

    Kwon, Gyoo Taik; Cho, Han Jin; Chung, Won-Yoon; Park, Kwang-Kyun; Moon, Aree; Park, Jung Han Yoon

    2009-09-01

    Isoliquiritigenin (ISL, 4,2',4'-trihydroxychalcone), which is found in licorice, shallot and bean sprouts, is a potent antioxidant with anti-inflammatory and anti-carcinogenic effects. The purpose of this study was to investigate the effects of ISL treatment on the migration, invasion and adhesion characteristics of DU145 human prostate cancer cells. DU145 cells were cultured in the presence of 0-20 micromol/L ISL with or without 10 microg/L epidermal growth factor (EGF). ISL inhibited basal and EGF-induced cell migration, invasion and adhesion dose dependently. ISL decreased EGF-induced secretion of urokinase-type plasminogen activator (uPA), matrix metalloproteinase (MMP)-9, tissue inhibitor of metalloproteinase-1 (TIMP-1), and vascular endothelial growth factor (VEGF), but increased TIMP-2 secretion in a concentration-dependent manner. In addition, ISL decreased the protein levels of integrin-alpha2, intercellular adhesion molecule (ICAM) and vascular cell adhesion molecule (VCAM), and mRNA levels of uPA, MMP-9, VEGF, ICAM and integrin-alpha2. Furthermore, basal and EGF-induced activator protein (AP)-1 binding activity and phosphorylation of Jun N-terminal kinase (JNK), c-Jun and Akt were decreased after ISL treatment. However, phosphorylation of extracellular signal-regulated kinase (ERK)1/2 and p38 mitogen-activated protein kinase was not altered. The JNK inhibitor SP600125 inhibited basal and EGF-induced secretion of uPA, VEGF, MMP-9 and TIMP-1, as well as AP-1 DNA binding activity and cell migration. These results provide evidence for the role of ISL as a potent antimetastatic agent, which can markedly inhibit the metastatic and invasive capacity of prostate cancer cells. The inhibition of JNK/AP-1 signaling may be one of the mechanisms by which ISL inhibits cancer cell invasion and migration. PMID:18824345

  2. Contrasting patterns in genetic diversity following multiple invasions of fresh and brackish waters.

    PubMed

    Kelly, David W; Muirhead, James R; Heath, Daniel D; Macisaac, Hugh J

    2006-10-01

    Biological invasions may combine the genetic effects of population bottlenecks and selection and thus provide valuable insight into the role of such processes during novel environmental colonizations. However, these processes are also influenced by multiple invasions, the number of individuals introduced and the degree of similarity between source and receiving habitats. The amphipod Gammarus tigrinus provides a useful model to assess these factors, as its invasion history has involved major environmental transitions. This species is native to the northwest Atlantic Ocean, although it invaded both brackish and freshwater habitats in the British Isles after introduction more than 65 years ago. It has also spread to similar habitats in Western Europe and, most recently, to Eastern Europe, the Baltic Sea, and the Laurentian Great Lakes. To examine sources of invasion and patterns of genetic change, we sampled populations from 13 native estuaries and 19 invaded sites and sequenced 542 bp of the mitochondrial COI gene. Strong native phylogeographical structure allowed us to unambiguously identify three allopatrically evolved clades (2.3-3.1% divergent) in invading populations, indicative of multiple introductions. The most divergent clades occurred in the British Isles and mainland Europe and were sourced from the St Lawrence and Chesapeake/Delaware Bay estuaries. A third clade was found in the Great Lakes and sourced to the Hudson River estuary. Despite extensive sampling, G. tigrinus did not occur in freshwater at putative source sites. Some European populations showed reduced genetic diversity consistent with bottlenecks, although selection effects cannot be excluded. The habitat distribution of clades in Europe was congruent with the known invasion history of secondary spread from the British Isles. Differences in salinity tolerance among lineages were suggested by patterns of habitat colonization by different native COI clades. Populations consisting of admixtures

  3. The effect of competition on the neutral intraspecific diversity of invasive species.

    PubMed

    Roques, L; Hosono, Y; Bonnefon, O; Boivin, T

    2015-08-01

    This paper deals with the effect of interspecific competition on the dynamics of neutral genetic diversity in a range-expanding population. The spread of an invasive species in an environment already hosting a resident competitor is described by a traveling wave solution with minimal speed, u(t,x) = U(x - c ∗ t), of a diffusive Lotka-Volterra competition model. The description of the dynamics of neutral genetic fractions in this wave is based on a decomposition of the wave into several components, as proposed by Roques et al. (Proc Natl Acad Sci USA 109(23):8828-8833, 2012). Our analytical results reveal that the wave can be either the pulled type, corresponding to strong erosion of the diversity, or the pushed type, corresponding to maintenance of the initial diversity. The pulled/pushed nature of the wave depends on the linear or nonlinear nature of the speed c *. Our results show that, for sufficiently strong competition, the speed is nonlinear, and therefore all of the genetic diversity in the invasive population is maintained. Conversely, in the absence of competition, or when competition is mild, the speed is linear, which means that only the furthest forward fraction in the initial invasive population eventually remains in the colonization front. Our numerical results also show that the sufficient conditions of Lewis et al. (J Math Biol 45(3):219-233, 2002) and Huang (J Dyn Differ Equ 22(2):285-297, 2010) for the linearity of the speed c * can still be improved, and they show that nonlinear speeds occur across a wide region of the parameter space, providing a counterpoint to recent analytical results suggesting that nonlinear speeds only occur in certain limiting cases. PMID:25193551

  4. Genetic diversity in three invasive clonal aquatic species in New Zealand

    PubMed Central

    2010-01-01

    Background Elodea canadensis, Egeria densa and Lagarosiphon major are dioecious clonal species which are invasive in New Zealand and other regions. Unlike many other invasive species, the genetic variation in New Zealand is very limited. Clonal reproduction is often considered an evolutionary dead end, even though a certain amount of genetic divergence may arise due to somatic mutations. The successful growth and establishment of invasive clonal species may be explained not by adaptability but by pre-existing ecological traits that prove advantageous in the new environment. We studied the genetic diversity and population structure in the North Island of New Zealand using AFLPs and related the findings to the number of introductions and the evolution that has occurred in the introduced area. Results Low levels of genetic diversity were found in all three species and appeared to be due to highly homogeneous founding gene pools. Elodea canadensis was introduced in 1868, and its populations showed more genetic structure than those of the more recently introduced of E. densa (1946) and L. major (1950). Elodea canadensis and L. major, however, had similar phylogeographic patterns, in spite of the difference in time since introduction. Conclusions The presence of a certain level of geographically correlated genetic structure in the absence of sexual reproduction, and in spite of random human dispersal of vegetative propagules, can be reasonably attributed to post-dispersal somatic mutations. Direct evidence of such evolutionary events is, however, still insufficient. PMID:20565861

  5. Floral diversity increases beneficial arthropod richness and decreases variability in arthropod community composition.

    PubMed

    Bennett, Ashley B; Gratton, Claudio

    2013-01-01

    Declines in species diversity resulting from anthropogenic alterations of the environment heighten the need to develop management strategies that conserve species and ecosystem services. This study examined how native plant species and their diversity influence the abundance and richness of beneficial arthropods, a functionally important group that provides ecosystem services such as pollination and natural pest suppression. Beneficial arthropods were sampled in replicated study plots containing native perennials planted in one-, two-, and seven-species mixtures. We found plant diversity had a positive impact on arthropod richness but not on arthropod abundance. An analysis of arthropod community composition revealed that each flower species attracted a different assemblage of beneficial arthropods. In addition, the full seven-species mixture also attracted a distinct arthropod community compared to single-species monocultures. Using a multivariate approach, we determined whether arthropod assemblages in two- and seven-species plots were additive and could be predicted based on assemblages from their component single-species plots. On average, assemblages in diverse plots were nonadditive when compared to assemblages predicted using single-species plots. Arthropod assemblages in two-species plots most closely resembled those of only one of the flower species in the mixture. However, the arthropod assemblages in seven-species plots, although statistically deviating from the expectation of an additive model, more closely resembled predicted communities compared to the assemblages found in two-species plots, suggesting that variability in arthropod community composition decreased as planting diversity increased. Our study demonstrates that careful selection of plants in managed landscapes can augment beneficial arthropod richness and support a more predictable arthropod community, suggesting that planning and design efforts could shape arthropod assemblages in natural

  6. Cell-free supernatants from probiotic Lactobacillus casei and Lactobacillus rhamnosus GG decrease colon cancer cell invasion in vitro.

    PubMed

    Escamilla, Juanita; Lane, Michelle A; Maitin, Vatsala

    2012-08-01

    Probiotics have been shown to have a preventative role in colorectal carcinogenesis but research concerning their prophylactic potential in the later stages of colorectal cancer, specifically metastasis is limited. This study explored the potential of cell-free supernatants (CFS) from 2 probiotic Lactobacillus sp., Lactobacillus casei and Lactobacillus rhamnosus GG, to inhibit colon cancer cell invasion by influencing matrix metalloproteinase-9 (MMP-9) activity and levels of the tight junction protein zona occludens-1 (ZO-1) in cultured metastatic human colorectal carcinoma cells. HCT-116 cells were treated with CFS from L. casei, L. rhamnosus, or Bacteroides thetaiotaomicron (a gut commensal); or with uninoculated bacterial growth media. Treatment with CFS from both Lactobacillus sp. decreased colorectal cell invasion but treatment with CFS from B. thetaiotaomicron did not. CFS from both Lactobacillus sp. decreased MMP-9 and increased ZO-1 protein levels. L. rhamnosus CFS also lowered MMP-9 activity. To begin elucidating the secreted bacterial factor conveying these responses, Lactobacillus sp. CFS were fractionated into defined molecular weight ranges and cell invasion assessed. Fractionation revealed that the inhibitory activity was contained primarily in the >100 kDa and 50-100 kDa fractions, suggesting the inhibitory compound may be a macromolecule such as a protein, nucleic acid, or a polysaccharide. PMID:22830611

  7. ERβ decreases the invasiveness of triple-negative breast cancer cells by regulating mutant p53 oncogenic function

    PubMed Central

    Bado, Igor; Nikolos, Fotis; Rajapaksa, Gayani; Gustafsson, Jan-Åke; Thomas, Christoforos

    2016-01-01

    Most (80%) of the triple-negative breast cancers (TNBCs) express mutant p53 proteins that acquire oncogenic activities including promoting metastasis. We previously showed that wild-type ERβ (ERβ1) impedes epithelial to mesenchymal transition (EMT) and decreases the invasiveness of TNBC cells. In the present study we searched for signaling pathways that ERβ1 uses to inhibit EMT and invasion in TNBC cells. We show that ERβ1 binds to and opposes the transcriptional activity of mutant p53 at the promoters of genes that regulate metastasis. p63 that transcriptionally cooperates with mutant p53 also binds to ERβ1. Downregulation of p63 represses the epithelial phenotype of ERβ1-expressing cells and alters the expression of mutant p53 target genes. These results describe a novel mechanism through which ERβ1 can disturb oncogenic signals to inhibit aggressiveness in TNBCs. PMID:26871946

  8. Luteolin decreases the attachment, invasion and cytotoxicity of UPEC in bladder epithelial cells and inhibits UPEC biofilm formation.

    PubMed

    Shen, Xiao-fei; Ren, Lai-bin; Teng, Yan; Zheng, Shuang; Yang, Xiao-long; Guo, Xiao-juan; Wang, Xin-yuan; Sha, Kai-hui; Li, Na; Xu, Guang-ya; Tian, Han-wen; Wang, Xiao-ying; Liu, Xiao-kang; Li, Jingyu; Huang, Ning

    2014-10-01

    Urinary tract infection (UTI), primarily caused by uropathogenic Escherichia coli (UPEC), is one of the most common infectious diseases worldwide. Emerging antibiotic resistance requires novel treatment strategies. Luteolin, a dietary polyphenolic flavonoid, has been confirmed as a potential antimicrobial agent. Here, we evaluated the sub-MICs of luteolin for potential properties to modulate the UPEC infection. We found that luteolin significantly decreased the attachment and invasion of UPEC J96 or CFT073 in human bladder epithelial cell lines T24. Meanwhile, obvious decreased expression of type 1 fimbriae adhesin fimH gene, lower bacterial surface hydrophobicity and swimming motility, were observed in luteolin-pretreated UPEC. Furthermore, luteolin could attenuate UPEC-induced cytotoxicity in T24 cells, which manifested as decreased activity of lactate dehydrogenase (LDH). Simultaneously, the inhibition of luteolin on UPEC-induced cytotoxicity was confirmed by ethidium bromide/acridine orange staining. Finally, the luteolin-pretreated UPEC showed a lower ability of biofilm formation. Collectively, these results indicated that luteolin decreased the attachment and invasion of UPEC in bladder epithelial cells, attenuated UPEC-induced cytotoxicity and biofilm formation via down-regulating the expression of adhesin fimH gene, reducing the bacterial surface hydrophobicity and motility.

  9. The influence of Aster x salignus Willd. Invasion on the diversity of soil yeast communities

    NASA Astrophysics Data System (ADS)

    Glushakova, A. M.; Kachalkin, A. V.; Chernov, I. Yu.

    2016-07-01

    The annual dynamics of yeast communities were studied in the soddy-podzolic soil under the thickets of Aster x salignus Willd., one of the widespread invasive plant species in central Russia. Yeast groups in the soils under continuous aster thickets were found to differ greatly from the yeast communities in the soils under the adjacent indigenous meadow vegetation. In both biotopes the same species ( Candida vartiovaarae, Candida sake, and Cryptococcus terreus) are dominants. However, in the soils under indigenous grasses, eurybiontic yeasts Rhodotorula mucilaginosa, which almost never occur in the soil under aster, are widespread. In the soil under aster, the shares of other typical epiphytic and pedobiontic yeast fungi (ascomycetic species Wickerhamomyces aniomalus, Barnettozyma californica and basidiomycetic species Cystofilobasidium macerans, Guehomyces pullulans) significantly increase. Thus, the invasion of Aster x salignus has a clear effect on soil yeast complexes reducing their taxonomic and ecological diversity.

  10. Decreased Diversity of the Oral Microbiota of Patients with Hepatitis B Virus-Induced Chronic Liver Disease: A Pilot Project.

    PubMed

    Ling, Zongxin; Liu, Xia; Cheng, Yiwen; Jiang, Xiawei; Jiang, Haiyin; Wang, Yuezhu; Li, Lanjuan

    2015-11-26

    Increasing evidence suggests that altered gut microbiota is implicated in the pathogenesis of hepatitis B virus-induced chronic liver disease (HBV-CLD). However, the structure and composition of the oral microbiota of patients with HBV-CLD remains unclear. High-throughput pyrosequencing showed that decreased oral bacterial diversity was found in patients with HBV-CLD. The Firmicutes/Bacteroidetes ratio was increased significantly, which indicated that dysbiosis of the oral microbiota participated in the process of HBV-CLD development. However, the changing patterns of the oral microbiota in patients with HBV-induced liver cirrhosis (LC) were almost similar to patients with chronic hepatitis B (CHB). HBV infection resulted in an increase in potential H2S- and CH3SH-producing phylotypes such as Fusobacterium, Filifactor, Eubacterium, Parvimonas and Treponema, which might contribute to the increased oral malodor. These key oral-derived phylotypes might invade into the gut as opportunistic pathogens and contribute to altering the composition of the gut microbiota. This study provided important clues that dysbiosis of the oral microbiota might be involved in the development of HBV-CLD. Greater understanding of the relationships between the dysbiosis of oral microbiota and the development of HBV-CLD might facilitate the development of non-invasive differential diagnostic procedures and targeted treatments of HBV-CLD patients harbouring specific oral phylotypes.

  11. Population Structure and Genetic Diversity of Native and Invasive Populations of Solanum rostratum (Solanaceae)

    PubMed Central

    Zhao, Jiali; Solís-Montero, Lislie; Lou, Anru; Vallejo-Marín, Mario

    2013-01-01

    Aims We investigate native and introduced populations of Solanum rostratum, an annual, self-compatible plant that has been introduced around the globe. This study is the first to compare the genetic diversity of Solanum rostratum between native and introduced populations. We aim to (1) determine the level of genetic diversity across the studied regions; (2) explore the likely origins of invasive populations in China; and (3) investigate whether there is the evidence of multiple introductions into China. Methods We genotyped 329 individuals at 10 microsatellite loci to determine the levels of genetic diversity and to investigate population structure of native and introduced populations of S. rostratum. We studied five populations in each of three regions across two continents: Mexico, the U.S.A. and China. Important Findings We found the highest genetic diversity among Mexican populations of S. rostratum. Genetic diversity was significantly lower in Chinese and U.S.A. populations, but we found no regional difference in inbreeding coefficients (FIS) or population differentiation (FST). Population structure analyses indicate that Chinese and U.S.A. populations are more closely related to each other than to sampled Mexican populations, revealing that introduced populations in China share an origin with the sampled U.S.A. populations. The distinctiveness between some introduced populations indicates multiple introductions of S. rostratum into China. PMID:24224008

  12. Decreased sirtuin 4 expression is associated with poor prognosis in patients with invasive breast cancer

    PubMed Central

    Shi, Qingyu; Liu, Tong; Zhang, Xianyu; Geng, Jingshu; He, Xiaohui; Nu, Ming; Pang, Da

    2016-01-01

    Aberrant metabolism is a hallmark of human cancer. Glutamine metabolism has been identified as a central metabolic pathway in cancer and thus, targeting glutamine metabolism may exhibit therapeutic potential. Sirtuin 4 (SIRT4) is an important molecule that mediates the blockade of glutamine catabolism by inhibiting glutamate dehydrogenase. In the present study, SIRT4 protein expression levels were analyzed in 409 breast cancer tissues and 241 paired adjacent non-cancerous tissues by immunohistochemical analysis and the correlation between SIRT4 expression and the clinicopathological features was evaluated. SIRT4 protein was markedly increased in the breast cancer cells compared with adjacent non-tumor mammary cells and was correlated with estrogen receptor, progesterone receptor, nuclear-associated antigen Ki-67 and tumor protein p53 status, as well as breast cancer subtypes. Furthermore, low SIRT4 expression was associated with poor overall survival in breast cancers patients, particularly in Luminal A patients. Univariate and multivariate analyses confirmed that increased SIRT4 expression was an independent predictive factor of good prognosis for breast cancer patients. In conclusion, SIRT4 expression represents a significant favorable prognostic factor for patients with invasive breast cancer. PMID:27698834

  13. Decreased sirtuin 4 expression is associated with poor prognosis in patients with invasive breast cancer

    PubMed Central

    Shi, Qingyu; Liu, Tong; Zhang, Xianyu; Geng, Jingshu; He, Xiaohui; Nu, Ming; Pang, Da

    2016-01-01

    Aberrant metabolism is a hallmark of human cancer. Glutamine metabolism has been identified as a central metabolic pathway in cancer and thus, targeting glutamine metabolism may exhibit therapeutic potential. Sirtuin 4 (SIRT4) is an important molecule that mediates the blockade of glutamine catabolism by inhibiting glutamate dehydrogenase. In the present study, SIRT4 protein expression levels were analyzed in 409 breast cancer tissues and 241 paired adjacent non-cancerous tissues by immunohistochemical analysis and the correlation between SIRT4 expression and the clinicopathological features was evaluated. SIRT4 protein was markedly increased in the breast cancer cells compared with adjacent non-tumor mammary cells and was correlated with estrogen receptor, progesterone receptor, nuclear-associated antigen Ki-67 and tumor protein p53 status, as well as breast cancer subtypes. Furthermore, low SIRT4 expression was associated with poor overall survival in breast cancers patients, particularly in Luminal A patients. Univariate and multivariate analyses confirmed that increased SIRT4 expression was an independent predictive factor of good prognosis for breast cancer patients. In conclusion, SIRT4 expression represents a significant favorable prognostic factor for patients with invasive breast cancer.

  14. Genetic Diversity and Population Structure in Polygonum cespitosum: Insights to an Ongoing Plant Invasion

    PubMed Central

    Matesanz, Silvia; Theiss, Kathryn E.; Holsinger, Kent E.; Sultan, Sonia E.

    2014-01-01

    Molecular markers can help elucidate how neutral evolutionary forces and introduction history contribute to genetic variation in invaders. We examined genetic diversity, population structure and colonization patterns in the invasive Polygonum cespitosum, a highly selfing, tetraploid Asian annual introduced to North America. We used nine diploidized polymorphic microsatellite markers to study 16 populations in the introduced range (northeastern North America), via the analyses of 516 individuals, and asked the following questions: 1) Do populations have differing levels of within-population genetic diversity? 2) Do populations form distinct genetic clusters? 3) Does population structure reflect either geographic distances or habitat similarities? We found low heterozygosity in all populations, consistent with the selfing mating system of P. cespitosum. Despite the high selfing levels, we found substantial genetic variation within and among P. cespitosum populations, based on the percentage of polymorphic loci, allelic richness, and expected heterozygosity. Inferences from individual assignment tests (Bayesian clustering) and pairwise FST values indicated high among-population differentiation, which indicates that the effects of gene flow are limited relative to those of genetic drift, probably due to the high selfing rates and the limited seed dispersal ability of P. cespitosum. Population structure did not reflect a pattern of isolation by distance nor was it related to habitat similarities. Rather, population structure appears to be the result of the random movement of propagules across the introduced range, possibly associated with human dispersal. Furthermore, the high population differentiation, genetic diversity, and fine-scale genetic structure (populations founded by individuals from different genetic sources) in the introduced range suggest that multiple introductions to this region may have occurred. High genetic diversity may further contribute to the

  15. Genotypic diversity of an invasive plant species promotes litter decomposition and associated processes.

    PubMed

    Wang, Xiao-Yan; Miao, Yuan; Yu, Shuo; Chen, Xiao-Yong; Schmid, Bernhard

    2014-03-01

    Following studies that showed negative effects of species loss on ecosystem functioning, newer studies have started to investigate if similar consequences could result from reductions of genetic diversity within species. We tested the influence of genotypic richness and dissimilarity (plots containing one, three, six or 12 genotypes) in stands of the invasive plant Solidago canadensis in China on the decomposition of its leaf litter and associated soil animals over five monthly time intervals. We found that the logarithm of genotypic richness was positively linearly related to mass loss of C, N and P from the litter and to richness and abundance of soil animals on the litter samples. The mixing proportion of litter from two sites, but not genotypic dissimilarity of mixtures, had additional effects on measured variables. The litter diversity effects on soil animals were particularly strong under the most stressful conditions of hot weather in July: at this time richness and abundance of soil animals were higher in 12-genotype litter mixtures than even in the highest corresponding one-genotype litter. The litter diversity effects on decomposition were in part mediated by soil animals: the abundance of Acarina, when used as covariate in the analysis, fully explained the litter diversity effects on mass loss of N and P. Overall, our study shows that high genotypic richness of S. canadensis leaf litter positively affects richness and abundance of soil animals, which in turn accelerate litter decomposition and P release from litter. PMID:24276771

  16. Functional Diversity of Boreal Bog Plant Species Decreases Seasonal Variation of Ecosystem Carbon Sink Function

    NASA Astrophysics Data System (ADS)

    Korrensalo, A.

    2015-12-01

    Species diversity has been found to decrease the temporal variance of productivity of a plant community, and diversity in species responses to environmental factors seems to make a plant community more stable in changing conditions. Boreal bogs are nutrient poor peatland ecosystems where the number of plant species is low but the species differ greatly in their growth form. In here we aim to assess the role of the variation in photosynthesis between species for the temporal variation in ecosystem carbon sink function. To quantify the photosynthetic properties and their seasonal variation for different bog plant species we measured photosynthetic parameters and stress-inducing chlorophyll fluorescence of vascular plant and Sphagnum moss species in a boreal bog over a growing season. We estimated monthly gross photosynthesis (PG) of the whole study site based on species level light response curves and leaf area development. The estimated PG was further compared with a gross primary production (GPP) estimate measured by eddy covariance (EC) technique. The sum of upscaled PG estimates agreed well with the GPP estimate measured by the EC technique. The contributions of the species and species groups to the ecosystem level PG changed over the growing season. The sharp mid-summer peak in sedge PG was balanced by more stable PG of evergreen shrubs and Sphagna. Species abundance rather than differences in photosynthetic properties between species and growth forms determined the most productive plants on the ecosystem scale. Sphagna had lower photosynthesis and clorophyll fluorescence than vascular plants but were more productive on the ecosystem scale throughout the growing season due to their high areal coverage. These results show that the diversity of growth forms stabilizes the seasonal variation of the ecosystem level PG in an ombrotrophic bog ecosystem. This may increase the resilience of the ecosystem to changing environmental conditions.

  17. Activated carbon decreases invasive plant growth by mediating plant-microbe interactions.

    PubMed

    Nolan, Nicole E; Kulmatiski, Andrew; Beard, Karen H; Norton, Jeanette M

    2014-01-01

    There is growing appreciation for the idea that plant-soil interactions (e.g. allelopathy and plant-microbe feedbacks) may explain the success of some non-native plants. Where this is the case, native plant restoration may require management tools that change plant-soil interactions. Activated carbon (AC) is one such potential tool. Previous research has shown the potential for high concentrations of AC to restore native plant growth to areas dominated by non-natives on a small scale (1 m × 1 m plots). Here we (i) test the efficacy of different AC concentrations at a larger scale (15 m × 15 m plots), (ii) measure microbial responses to AC treatment and (iii) use a greenhouse experiment to identify the primary mechanism, allelopathy versus microbial changes, through which AC impacts native and non-native plant growth. Three years after large-scale applications, AC treatments decreased non-native plant cover and increased the ratio of native to non-native species cover, particularly at concentrations >400 g m(-2). Activated carbon similarly decreased non-native plant growth in the greenhouse. This effect, however, was only observed in live soils, suggesting that AC effects were microbially mediated and not caused by direct allelopathy. Bacterial community analysis of field soils indicated that AC increased the relative abundance of an unidentified bacterium and an Actinomycetales and decreased the relative abundance of a Flavobacterium, suggesting that these organisms may play a role in AC effects on plant growth. Results support the idea that manipulations of plant-microbe interactions may provide novel and effective ways of directing plant growth and community development (e.g. native plant restoration). PMID:25387751

  18. Activated carbon decreases invasive plant growth by mediating plant–microbe interactions

    PubMed Central

    Nolan, Nicole E.; Kulmatiski, Andrew; Beard, Karen H.; Norton, Jeanette M.

    2015-01-01

    There is growing appreciation for the idea that plant–soil interactions (e.g. allelopathy and plant–microbe feedbacks) may explain the success of some non-native plants. Where this is the case, native plant restoration may require management tools that change plant–soil interactions. Activated carbon (AC) is one such potential tool. Previous research has shown the potential for high concentrations of AC to restore native plant growth to areas dominated by non-natives on a small scale (1 m × 1 m plots). Here we (i) test the efficacy of different AC concentrations at a larger scale (15 m × 15 m plots), (ii) measure microbial responses to AC treatment and (iii) use a greenhouse experiment to identify the primary mechanism, allelopathy versus microbial changes, through which AC impacts native and non-native plant growth. Three years after large-scale applications, AC treatments decreased non-native plant cover and increased the ratio of native to non-native species cover, particularly at concentrations >400 g m−2. Activated carbon similarly decreased non-native plant growth in the greenhouse. This effect, however, was only observed in live soils, suggesting that AC effects were microbially mediated and not caused by direct allelopathy. Bacterial community analysis of field soils indicated that AC increased the relative abundance of an unidentified bacterium and an Actinomycetales and decreased the relative abundance of a Flavobacterium, suggesting that these organisms may play a role in AC effects on plant growth. Results support the idea that manipulations of plant–microbe interactions may provide novel and effective ways of directing plant growth and community development (e.g. native plant restoration). PMID:25387751

  19. Resistome diversity in cattle and the environment decreases during beef production.

    PubMed

    Noyes, Noelle R; Yang, Xiang; Linke, Lyndsey M; Magnuson, Roberta J; Dettenwanger, Adam; Cook, Shaun; Geornaras, Ifigenia; Woerner, Dale E; Gow, Sheryl P; McAllister, Tim A; Yang, Hua; Ruiz, Jaime; Jones, Kenneth L; Boucher, Christina A; Morley, Paul S; Belk, Keith E

    2016-01-01

    Antimicrobial resistant determinants (ARDs) can be transmitted from livestock systems through meat products or environmental effluents. The public health risk posed by these two routes is not well understood, particularly in non-pathogenic bacteria. We collected pooled samples from 8 groups of 1741 commercial cattle as they moved through the process of beef production from feedlot entry through slaughter. We recorded antimicrobial drug exposures and interrogated the resistome at points in production when management procedures could potentially influence ARD abundance and/or transmission. Over 300 unique ARDs were identified. Resistome diversity decreased while cattle were in the feedlot, indicating selective pressure. ARDs were not identified in beef products, suggesting that slaughter interventions may reduce the risk of transmission of ARDs to beef consumers. This report highlights the utility and limitations of metagenomics for assessing public health risks regarding antimicrobial resistance, and demonstrates that environmental pathways may represent a greater risk than the food supply. PMID:26952213

  20. Resistome diversity in cattle and the environment decreases during beef production.

    PubMed

    Noyes, Noelle R; Yang, Xiang; Linke, Lyndsey M; Magnuson, Roberta J; Dettenwanger, Adam; Cook, Shaun; Geornaras, Ifigenia; Woerner, Dale E; Gow, Sheryl P; McAllister, Tim A; Yang, Hua; Ruiz, Jaime; Jones, Kenneth L; Boucher, Christina A; Morley, Paul S; Belk, Keith E

    2016-03-08

    Antimicrobial resistant determinants (ARDs) can be transmitted from livestock systems through meat products or environmental effluents. The public health risk posed by these two routes is not well understood, particularly in non-pathogenic bacteria. We collected pooled samples from 8 groups of 1741 commercial cattle as they moved through the process of beef production from feedlot entry through slaughter. We recorded antimicrobial drug exposures and interrogated the resistome at points in production when management procedures could potentially influence ARD abundance and/or transmission. Over 300 unique ARDs were identified. Resistome diversity decreased while cattle were in the feedlot, indicating selective pressure. ARDs were not identified in beef products, suggesting that slaughter interventions may reduce the risk of transmission of ARDs to beef consumers. This report highlights the utility and limitations of metagenomics for assessing public health risks regarding antimicrobial resistance, and demonstrates that environmental pathways may represent a greater risk than the food supply.

  1. Distinguishing between invasions and habitat changes as drivers of diversity loss among California's freshwater fishes.

    PubMed

    Light, Theo; Marchetti, Michael P

    2007-04-01

    Many of California's native populations of freshwater fish are in serious decline, as are freshwater faunas worldwide. Habitat loss and alteration, hydrologic modification, water pollution, and invasions have been identified as major drivers of these losses. Because these potential causes of decline are frequently correlated, it is difficult to separate direct from indirect effects of each factor and to appropriately rank their importance for conservation action. Recently a few authors have questioned the conservation significance of invasions, suggesting that they are "passengers" rather than "drivers" of ecological change. We compiled an extensive, watershed-level data set of fish presence and conservation status, land uses, and hydrologic modifications in California and used an information theoretic approach (Akaike's information criterion, AIC) and path analysis to evaluate competing models of native fish declines. Hydrologic modification (impoundments and diversions), invasions, and proportion of developed land were all predictive of the number of extinct and at-risk native fishes in California watersheds in the AIC analysis. Although nonindigenous fish richness was the best single predictor (after native richness) of fishes of conservation concern, the combined ranking of models containing hydrologic modification variables was slightly higher than that of models containing nonindigenous richness. Nevertheless, the path analysis indicated that the effects of both hydrologic modification and development on fishes of conservation concern were largely indirect, through their positive effects on nonindigenous fish richness. The best-fitting path model was the driver model, which included no direct effects of abiotic disturbance on native fish declines. Our results suggest that, for California freshwater fishes, invasions are the primary direct driver of extinctions and population declines, whereas the most damaging effect of habitat alteration is the tendency of

  2. Serotypes and Clonal Diversity of Streptococcus pneumoniae Causing Invasive Disease in the Era of PCV13 in Catalonia, Spain

    PubMed Central

    del Amo, Eva; Esteva, Cristina; Hernandez-Bou, Susanna; Galles, Carmen; Navarro, Marian; Sauca, Goretti; Diaz, Alvaro; Gassiot, Paula; Marti, Carmina; Larrosa, Nieves; Ciruela, Pilar; Jane, Mireia; Sá-Leão, Raquel; Muñoz-Almagro, Carmen

    2016-01-01

    The aim of this study was to study the serotypes and clonal diversity of pneumococci causing invasive pneumococcal disease in Catalonia, Spain, in the era of 13-valent pneumococcal conjugate vaccine (PCV13). In our region, this vaccine is only available in the private market and it is estimated a PCV13 vaccine coverage around 55% in children. A total of 1551 pneumococcal invasive isolates received between 2010 and 2013 in the Molecular Microbiology Department at Hospital Sant Joan de Déu, Barcelona, were included. Fifty-two serotypes and 249 clonal types—defined by MLST—were identified. The most common serotypes were serotype 1 (n = 182; 11.7%), 3 (n = 145; 9.3%), 19A (n = 137; 8.8%) and 7F (n = 122; 7.9%). Serotype 14 was the third most frequent serotype in children < 2 years (15 of 159 isolates). PCV7 serotypes maintained their proportion along the period of study, 16.6% in 2010 to 13.4% in 2013, whereas there was a significant proportional decrease in PCV13 serotypes, 65.3% in 2010 to 48.9% in 2013 (p<0.01). This decrease was mainly attributable to serotypes 19A and 7F. Serotype 12F achieved the third position in 2013 (n = 22, 6.4%). The most frequent clonal types found were ST306 (n = 154, 9.9%), ST191 (n = 111, 7.2%), ST989 (n = 85, 5.5%) and ST180 (n = 80, 5.2%). Despite their decrease, PCV13 serotypes continue to be a major cause of disease in Spain. These results emphasize the need for complete PCV13 vaccination. PMID:26953887

  3. Population structure and diversity of an invasive pine needle pathogen reflects anthropogenic activity

    PubMed Central

    Barnes, Irene; Wingfield, Michael J; Carbone, Ignazio; Kirisits, Thomas; Wingfield, Brenda D

    2014-01-01

    Dothistroma septosporum is a haploid fungal pathogen that causes a serious needle blight disease of pines, particularly as an invasive alien species on Pinus radiata in the Southern Hemisphere. During the course of the last two decades, the pathogen has also incited unexpected epidemics on native and non-native pine hosts in the Northern Hemisphere. Although the biology and ecology of the pathogen has been well documented, there is a distinct lack of knowledge regarding its movement or genetic diversity in many of the countries where it is found. In this study we determined the global population diversity and structure of 458 isolates of D. septosporum from 14 countries on six continents using microsatellite markers. Populations of the pathogen in the Northern Hemisphere, where pines are native, displayed high genetic diversities and included both mating types. Most of the populations from Europe showed evidence for random mating, little population differentiation and gene flow between countries. Populations in North America (USA) and Asia (Bhutan) were genetically distinct but migration between these continents and Europe was evident. In the Southern Hemisphere, the population structure and diversity of D. septosporum reflected the anthropogenic history of the introduction and establishment of plantation forestry, particularly with Pinus radiata. Three introductory lineages in the Southern Hemisphere were observed. Countries in Africa, that have had the longest history of pine introductions, displayed the greatest diversity in the pathogen population, indicating multiple introductions. More recent introductions have occurred separately in South America and Australasia where the pathogen population is currently reproducing clonally due to the presence of only one mating type. PMID:25478155

  4. Orthotopic urinary diversion after radical cystectomy in treatment of muscle invasive bladder cancer.

    PubMed

    Jovan, Hadži-Djokić; Vladan, Andrejević; Tomislav, Pejčić; Miodrag, Aćimović; Uroš, Babić; Miodrag, Stanić; Zoran, Džamić

    2014-01-01

    Surgical treatment of invasive carcinoma of the bladder in males includes total cystectomy removal of the prostate, seminal vesicles, and the distal parts of the urethers and the pelvic lymph node dissection as well. At this moment it is not possible to recommend a particular type of urinary diversion, but today in clinical practice commonly used derivative are ileal orthotopic neobladder as the continent one and ileal conduit as non-continent urinary diversion. Continent urinary diversion after radical cystectomy are the result of the application of technological innovation in surgery, but also knowledge, imagination and skill of well trained urologist. This type of operation significantly improves the quality of life in patients who underwent radical cystectomy, and the proposal is to operate whenever there is a possibility for this type of procedure. Also it is very important, during surgery to respect oncological principles, of complete removal of tumorous tissue and that the functional principle of ensur- ing that the patients have daytime and also nighttime continence later on after the surgery.

  5. Decreased FOXF1 promotes hepatocellular carcinoma tumorigenesis, invasion, and stemness and is associated with poor clinical outcome

    PubMed Central

    Zhao, Zhen-guo; Wang, De-qiang; Hu, De-fei; Li, You-sheng; Liu, Shuang-hai

    2016-01-01

    Forkhead box F1 (FOXF1), a member of the forkhead transcription factor superfamily, plays critical roles in the progression of certain types of cancers. However, the expression and function of FOXF1 in human hepatocellular carcinoma (HCC) are still unclear. Quantitative real-time reverse transcription polymerase chain reaction, Western blotting, and immunohistochemistry detected the relatively lower expression status of FOXF1 in HCC cases. Soft agar and transwell assays clearly demonstrated that FOXF1-knockdown cells showed significantly increased in vitro cell tumorigenesis and invasion, and FOXF1-overexpressing cells had significantly reduced growth and invasion potential. Our study also examined the role of FOXF1 in HCC cell stemness by sphere formation, aldehyde dehydrogenase (ALDH1) activity, and CD44/133-positive cell analysis. Enforced FOXF1 expression decreased HCC cell stemness, and the downregulation of FOXF1 promoted cancer cell stemness. The in vivo study showed that overexpressed FOXF1 inhibits nude mouse tumorigenicity with downregulation of CD44 and proliferating cell nuclear antigen. More importantly, loss of FOXF1 expression was linked to poor overall survival time by Kaplan–Meier analysis. PMID:27042124

  6. Inter-varietal interactions among plants in genotypically diverse mixtures tend to decrease herbivore performance.

    PubMed

    Grettenberger, Ian M; Tooker, John F

    2016-09-01

    Much research has explored the effects of plant species diversity on herbivore populations, but far less has considered effects of plant genotypic diversity, or how abiotic stressors, like drought, can modify effects. Mechanisms by which plant genotypic diversity affects herbivore populations remain largely unresolved. We used greenhouse studies with a model system of wheat (Triticum aestivum L.) and bird cherry-oat aphid (Rhopalosiphum padi L.) to determine whether the genotypic diversity of a plant's neighborhood influences performance and fitness of herbivores on a focal plant and if drought changes the influence of neighborhood diversity. Taken across all varieties we tested, plant-plant interactions in diverse neighborhoods reduced aphid performance and generated associational resistance, although effects on aphids depended on variety identity. In diverse mixtures, drought stress greatly diminished the genotypic diversity-driven reduction in aphid performance. Neighborhood diversity influenced mother aphid size, and appeared to partially explain how plant-plant interactions reduced the number of offspring produced in mixtures. Plant size did not mediate effects on aphid performance, although neighborhood diversity reduced plant mass across varieties and watering treatments. Our results suggest inter-varietal interactions in genotypic mixtures can affect herbivore performance in the absence of herbivore movement and that abiotic stress may diminish any effects. Accounting for how neighborhood diversity influences resistance of an individual plant to herbivores will help aid development of mixtures of varieties for managing insect pests and clarify the role of plant genotypic diversity in ecosystems.

  7. Inter-varietal interactions among plants in genotypically diverse mixtures tend to decrease herbivore performance.

    PubMed

    Grettenberger, Ian M; Tooker, John F

    2016-09-01

    Much research has explored the effects of plant species diversity on herbivore populations, but far less has considered effects of plant genotypic diversity, or how abiotic stressors, like drought, can modify effects. Mechanisms by which plant genotypic diversity affects herbivore populations remain largely unresolved. We used greenhouse studies with a model system of wheat (Triticum aestivum L.) and bird cherry-oat aphid (Rhopalosiphum padi L.) to determine whether the genotypic diversity of a plant's neighborhood influences performance and fitness of herbivores on a focal plant and if drought changes the influence of neighborhood diversity. Taken across all varieties we tested, plant-plant interactions in diverse neighborhoods reduced aphid performance and generated associational resistance, although effects on aphids depended on variety identity. In diverse mixtures, drought stress greatly diminished the genotypic diversity-driven reduction in aphid performance. Neighborhood diversity influenced mother aphid size, and appeared to partially explain how plant-plant interactions reduced the number of offspring produced in mixtures. Plant size did not mediate effects on aphid performance, although neighborhood diversity reduced plant mass across varieties and watering treatments. Our results suggest inter-varietal interactions in genotypic mixtures can affect herbivore performance in the absence of herbivore movement and that abiotic stress may diminish any effects. Accounting for how neighborhood diversity influences resistance of an individual plant to herbivores will help aid development of mixtures of varieties for managing insect pests and clarify the role of plant genotypic diversity in ecosystems. PMID:27170329

  8. Characterization of Genetic and Phenotypic Diversity of Invasive Nontypeable Haemophilus influenzae

    PubMed Central

    Erwin, Alice L.; Nelson, Kevin L.; Mhlanga-Mutangadura, Tendai; Bonthuis, Paul J.; Geelhood, Jennifer L.; Morlin, Gregory; Unrath, William C. T.; Campos, Jose; Crook, Derrick W.; Farley, Monica M.; Henderson, Frederick W.; Jacobs, Richard F.; Mühlemann, Kathrin; Satola, Sarah W.; van Alphen, Loek; Golomb, Miriam; Smith, Arnold L.

    2005-01-01

    The ability of unencapsulated (nontypeable) Haemophilus influenzae (NTHi) to cause systemic disease in healthy children has been recognized only in the past decade. To determine the extent of similarity among invasive nontypeable isolates, we compared strain R2866 with 16 additional NTHi isolates from blood and spinal fluid, 17 nasopharyngeal or throat isolates from healthy children, and 19 isolates from middle ear aspirates. The strains were evaluated for the presence of several genetic loci that affect bacterial surface structures and for biochemical reactions that are known to differ among H. influenzae strains. Eight strains, including four blood isolates, shared several properties with R2866: they were biotype V (indole and ornithine decarboxylase positive, urease negative), contained sequence from the adhesin gene hia, and lacked a genetic island flanked by the infA and ksgA genes. Multilocus sequence typing showed that most biotype V isolates belonged to the same phylogenetic cluster as strain R2866. When present, the infA-ksgA island contains lipopolysaccharide biosynthetic genes, either lic2B and lic2C or homologs of the losA and losB genes described for Haemophilus ducreyi. The island was found in most nasopharyngeal and otitis isolates but was absent from 40% of invasive isolates. Overall, the 33 hmw-negative isolates were much more likely than hmw-containing isolates to have tryptophanase, ornithine decarboxylase, or lysine decarboxylase activity or to contain the hif genes. We conclude (i) that invasive isolates are genetically and phenotypically diverse and (ii) that certain genetic loci of NTHi are frequently found in association among NTHi strains. PMID:16113304

  9. Amplicon pyrosequencing reveals the soil microbial diversity associated with invasive Japanese barberry (Berberis thunbergii DC.).

    PubMed

    Coats, V C; Pelletreau, K N; Rumpho, M E

    2014-03-01

    The soil microbial community acts as a reservoir of microbes that directly influences the structure and composition of the aboveground plant community, promotes plant growth, increases stress tolerance and mediates local patterns of nutrient cycling. Direct interactions between plants and rhizosphere-dwelling microorganisms occur at, or near, the surface of the root. Upon introduction and establishment, invasive plants modify the soil microbial communities and soil biochemistry affecting bioremediation efforts and future plant communities. Here, we used tag-encoded FLX amplicon 454 pyrosequencing (TEFAP) to characterize the bacterial and fungal community diversity in the rhizosphere of Berberis thunbergii DC. (Japanese barberry) from invasive stands in coastal Maine to investigate effects of soil type, soil chemistry and surrounding plant cover on the soil microbial community structure. Acidobacteria, Actinobacteria, Proteobacteria and Verrucomicrobia were the dominant bacterial phyla, whereas fungal communities were comprised mostly of Ascomycota and Basidiomycota phyla members, including Agaricomycetes and Sordariomycetes. Bulk soil chemistry had more effect on the bacterial community structure than the fungal community. An effect of geographic location was apparent in the rhizosphere microbial communities, yet it was less significant than the effect of surrounding plant cover. These data demonstrate a high degree of spatial variation in the rhizosphere microbial communities of Japanese barberry with apparent effects of soil chemistry, location and canopy cover on the microbial community structure.

  10. Resistome diversity in cattle and the environment decreases during beef production

    PubMed Central

    Noyes, Noelle R; Yang, Xiang; Linke, Lyndsey M; Magnuson, Roberta J; Dettenwanger, Adam; Cook, Shaun; Geornaras, Ifigenia; Woerner, Dale E; Gow, Sheryl P; McAllister, Tim A; Yang, Hua; Ruiz, Jaime; Jones, Kenneth L; Boucher, Christina A; Morley, Paul S; Belk, Keith E

    2016-01-01

    Antimicrobial resistant determinants (ARDs) can be transmitted from livestock systems through meat products or environmental effluents. The public health risk posed by these two routes is not well understood, particularly in non-pathogenic bacteria. We collected pooled samples from 8 groups of 1741 commercial cattle as they moved through the process of beef production from feedlot entry through slaughter. We recorded antimicrobial drug exposures and interrogated the resistome at points in production when management procedures could potentially influence ARD abundance and/or transmission. Over 300 unique ARDs were identified. Resistome diversity decreased while cattle were in the feedlot, indicating selective pressure. ARDs were not identified in beef products, suggesting that slaughter interventions may reduce the risk of transmission of ARDs to beef consumers. This report highlights the utility and limitations of metagenomics for assessing public health risks regarding antimicrobial resistance, and demonstrates that environmental pathways may represent a greater risk than the food supply. DOI: http://dx.doi.org/10.7554/eLife.13195.001 PMID:26952213

  11. Invasion of dwarf bamboo into alpine snow-meadows in northern Japan: pattern of expansion and impact on species diversity

    PubMed Central

    Kudo, Gaku; Amagai, Yukihiro; Hoshino, Buho; Kaneko, Masami

    2011-01-01

    Recently, a dwarf bamboo species,Sasa kurilensis; Poaceae, has invaded into alpine snow-meadows in the wilderness area of the Taisetsu Mountains, northern Japan. This dwarf bamboo species has a wide distribution range from lowland to alpine sites of snowy regions. Because of the formation of dense evergreen culms and an extensive rhizome system, other plants are excluded following invasion by this dwarf bamboo, resulting in low species diversity. Dwarf bamboo originally inhabited the leeward slopes of alpine dwarf pine (Pinus pumila) clumps in alpine regions. During the last 32 years, however, dwarf bamboo has expanded its distribution area by up to 47% toward snow-meadows, especially on southeastern facing slopes. This rapid change may be related to the decrease in soil moisture and expansion of the annual growing period caused by the recent acceleration of snowmelt time. A multiyear census revealed that the density of bamboo culms increased 30–150% during 2 years, and the annual expansion of bamboo rhizomes was 39 cm on average. In addition to the expansion of bamboo clumps by vegetative growth, the possibility of migration by seed dispersal was also suggested by a genet analysis. With the increase in culm density, the species richness of snow-meadow vegetation decreased to less than one-quarter of the original level due to intense shading by dwarf bamboo. The rapid vegetation change in these almost pristine alpine environments isolated from the human activity implies that global climate change already influences the alpine ecosystem. PMID:22393485

  12. Invasion of dwarf bamboo into alpine snow-meadows in northern Japan: pattern of expansion and impact on species diversity.

    PubMed

    Kudo, Gaku; Amagai, Yukihiro; Hoshino, Buho; Kaneko, Masami

    2011-09-01

    Recently, a dwarf bamboo species,Sasa kurilensis; Poaceae, has invaded into alpine snow-meadows in the wilderness area of the Taisetsu Mountains, northern Japan. This dwarf bamboo species has a wide distribution range from lowland to alpine sites of snowy regions. Because of the formation of dense evergreen culms and an extensive rhizome system, other plants are excluded following invasion by this dwarf bamboo, resulting in low species diversity. Dwarf bamboo originally inhabited the leeward slopes of alpine dwarf pine (Pinus pumila) clumps in alpine regions. During the last 32 years, however, dwarf bamboo has expanded its distribution area by up to 47% toward snow-meadows, especially on southeastern facing slopes. This rapid change may be related to the decrease in soil moisture and expansion of the annual growing period caused by the recent acceleration of snowmelt time. A multiyear census revealed that the density of bamboo culms increased 30-150% during 2 years, and the annual expansion of bamboo rhizomes was 39 cm on average. In addition to the expansion of bamboo clumps by vegetative growth, the possibility of migration by seed dispersal was also suggested by a genet analysis. With the increase in culm density, the species richness of snow-meadow vegetation decreased to less than one-quarter of the original level due to intense shading by dwarf bamboo. The rapid vegetation change in these almost pristine alpine environments isolated from the human activity implies that global climate change already influences the alpine ecosystem.

  13. Bird functional diversity decreases with time since disturbance: Does patchy prescribed fire enhance ecosystem function?.

    PubMed

    Sitters, Holly; Di Stefano, Julian; Christie, Fiona; Swan, Matthew; York, Alan

    2016-01-01

    Animal species diversity is often associated with time since disturbance, but the effects of disturbances such as fire on functional diversity are unknown. Functional diversity measures the range, abundance, and distribution of trait values in a community, and links changes in species composition with the consequences for ecosystem function. Improved understanding of the relationship between time since fire (TSF) and functional diversity is critical given that the frequency of both prescribed fire and wildfire is expected to increase. To address this knowledge gap, we examined responses of avian functional diversity to TSF and two direct measures of environmental heterogeneity, plant diversity, and structural heterogeneity. We surveyed birds across a 70-year chronosequence spanning four vegetation types in southeast Australia. Six bird functional traits were used to derive four functional diversity indices (richness, evenness, divergence, and dispersion) and the effects of TSF, plant diversity and structural heterogeneity on species richness and the functional diversity indices were examined using mixed models. We used a regression tree method to identify traits associated with species more common in young vegetation. Functional richness and dispersion were negatively associated with TSF in all vegetation types, suggesting that recent prescribed fire generates heterogeneous vegetation and provides greater opportunities for resource partitioning. Species richness was not significantly associated with TSF, and is probably an unreliable surrogate for functional diversity in fire-prone systems. A positive, relationship between functional evenness and structural heterogeneity was comnon to all vegetation types, suggesting that fine-scale (tens of meters) structural variation can enhance ecosystem function. Species more common in young vegetation were primarily linked by their specialist diets, indicating that ecosystem services such as seed dispersal and insect control

  14. Bird functional diversity decreases with time since disturbance: Does patchy prescribed fire enhance ecosystem function?.

    PubMed

    Sitters, Holly; Di Stefano, Julian; Christie, Fiona; Swan, Matthew; York, Alan

    2016-01-01

    Animal species diversity is often associated with time since disturbance, but the effects of disturbances such as fire on functional diversity are unknown. Functional diversity measures the range, abundance, and distribution of trait values in a community, and links changes in species composition with the consequences for ecosystem function. Improved understanding of the relationship between time since fire (TSF) and functional diversity is critical given that the frequency of both prescribed fire and wildfire is expected to increase. To address this knowledge gap, we examined responses of avian functional diversity to TSF and two direct measures of environmental heterogeneity, plant diversity, and structural heterogeneity. We surveyed birds across a 70-year chronosequence spanning four vegetation types in southeast Australia. Six bird functional traits were used to derive four functional diversity indices (richness, evenness, divergence, and dispersion) and the effects of TSF, plant diversity and structural heterogeneity on species richness and the functional diversity indices were examined using mixed models. We used a regression tree method to identify traits associated with species more common in young vegetation. Functional richness and dispersion were negatively associated with TSF in all vegetation types, suggesting that recent prescribed fire generates heterogeneous vegetation and provides greater opportunities for resource partitioning. Species richness was not significantly associated with TSF, and is probably an unreliable surrogate for functional diversity in fire-prone systems. A positive, relationship between functional evenness and structural heterogeneity was comnon to all vegetation types, suggesting that fine-scale (tens of meters) structural variation can enhance ecosystem function. Species more common in young vegetation were primarily linked by their specialist diets, indicating that ecosystem services such as seed dispersal and insect control

  15. Invasive species and habitat degradation in Iberian streams: an analysis of their role in freshwater fish diversity loss.

    PubMed

    Hermoso, Virgilio; Clavero, Miguel; Blanco-Garrido, Francisco; Prenda, José

    2011-01-01

    Mediterranean endemic freshwater fish are among the most threatened biota in the world. Distinguishing the role of different extinction drivers and their potential interactions is crucial for achieving conservation goals. While some authors argue that invasive species are a main driver of native species declines, others see their proliferation as a co-occurring process to biodiversity loss driven by habitat degradation. It is difficult to discern between the two potential causes given that few invaded ecosystems are free from habitat degradation, and that both factors may interact in different ways. Here we analyze the relative importance of habitat degradation and invasive species in the decline of native fish assemblages in the Guadiana River basin (southwestern Iberian Peninsula) using an information theoretic approach to evaluate interaction pathways between invasive species and habitat degradation (structural equation modeling, SEM). We also tested the possible changes in the functional relationships between invasive and native species, measured as the per capita effect of invasive species, using ANCOVA. We found that the abundance of invasive species was the best single predictor of natives' decline and had the highest Akaike weight among the set of predictor variables examined. Habitat degradation neither played an active role nor influenced the per capita effect of invasive species on natives. Our analyses indicated that downstream reaches and areas close to reservoirs had the most invaded fish assemblages, independently of their habitat degradation status. The proliferation of invasive species poses a strong threat to the persistence of native assemblages in highly fluctuating environments. Therefore, conservation efforts to reduce native freshwater fish diversity loss in Mediterranean rivers should focus on mitigating the effect of invasive species and preventing future invasions.

  16. Soil-occupancy effects of invasive and native grassland plant species on composition and diversity of mycorrhizal associations

    USGS Publications Warehouse

    Jordan, Nicholas R.; Aldrich-Wolfe, Laura; Huerd, Sheri C.; Larson, Diane L.; Muehlbauer, Gary

    2012-01-01

    Diversified grasslands that contain native plant species can produce biofuels, support sustainable grazing systems, and produce other ecosystem services. However, ecosystem service production can be disrupted by invasion of exotic perennial plants, and these plants can have soil-microbial “legacies” that may interfere with establishment and maintenance of diversified grasslands even after effective management of the invasive species. The nature of such legacies is not well understood, but may involve suppression of mutualisms between native species and soil microbes. In this study, we tested the hypotheses that legacy effects of invasive species change colonization rates, diversity, and composition of arbuscular-mycorrhizal fungi (AMF) associated with seedlings of co-occurring invasive and native grassland species. In a glasshouse, experimental soils were conditioned by cultivating three invasive grassland perennials, three native grassland perennials, and a native perennial mixture. Each was grown separately through three cycles of growth, after which we used T-RFLP analysis to characterize AMF associations of seedlings of six native perennial and six invasive perennial species grown in these soils. Legacy effects of soil conditioning by invasive species did not affect AMF richness in seedling roots, but did affect AMF colonization rates and the taxonomic composition of mycorrhizal associations in seedling roots. Moreover, native species were more heavily colonized by AMF and roots of native species had greater AMF richness (number of AMF operational taxonomic units per seedling) than did invasive species. The invasive species used to condition soil in this experiment have been shown to have legacy effects on biomass of native seedlings, reducing their growth in this and a previous similar experiment. Therefore, our results suggest that successful plant invaders can have legacies that affect soil-microbial associations of native plants and that these effects

  17. Invasive Chloroplast Population Genetics of Mikania micrantha in China: No Local Adaptation and Negative Correlation between Diversity and Geographic Distance

    PubMed Central

    Wang, Ting; Wang, Zhen; Chen, Guopei; Wang, Chunbo; Su, Yingjuan

    2016-01-01

    Two fundamental questions on how invasive species are able to rapidly colonize novel habitat have emerged. One asks whether a negative correlation exists between the genetic diversity of invasive populations and their geographic distance from the origin of introduction. The other is whether selection on the chloroplast genome is important driver of adaptation to novel soil environments. Here, we addressed these questions in a study of the noxious invasive weed, Mikania micrantha, which has rapidly expanded in to southern China after being introduced to Hong Kong in 1884. Seven chloroplast simple sequence repeats (cpSSRs) were used to investigate population genetics in 28 populations of M. micrantha, which produced 39 loci. The soil compositions for these populations, including Mg abundance, were measured. The results showed that M. micrantha possessed relatively high cpSSR variation and differentiation among populations. Multiple diversity indices were quantified, and none was significantly correlated with distance from the origin of introduction. No evidence for “isolation by distance,” significant spatial structure, bottlenecks, nor linkage disequilibrium was detected. We also were unable to identify loci on the chloroplast genome that exhibited patterns of differentiation that would suggest adaptive evolution in response to soil attributes. Soil Mg had only a genome-wide effect instead of being a selective factor, which highlighted the association between Mg and the successful invasion. This study characterizes the role of the chloroplast genome of M. micrantha during its recent invasion of southern China. PMID:27708663

  18. Calibrating snakehead diversity with DNA barcodes: expanding taxonomic coverage to enable identification of potential and established invasive species.

    PubMed

    Serrao, Natasha R; Steinke, Dirk; Hanner, Robert H

    2014-01-01

    Detecting and documenting the occurrence of invasive species outside their native range requires tools to support their identification. This can be challenging for taxa with diverse life stages and/or problematic or unresolved morphological taxonomies. DNA barcoding provides a potent method for identifying invasive species, as it allows for species identification at all life stages, including fragmentary remains. It also provides an efficient interim taxonomic framework for quantifying cryptic genetic diversity by parsing barcode sequences into discontinuous haplogroup clusters (typical of reproductively isolated species) and labelling them with unique alphanumeric identifiers. Snakehead fishes are a diverse group of opportunistic predators endemic to Asia and Africa that may potentially pose significant threats as aquatic invasive species. At least three snakehead species (Channa argus, C. maculata, and C. marulius) are thought to have entered North America through the aquarium and live-food fish markets, and have established populations, yet their origins remain unclear. The objectives of this study were to assemble a library of DNA barcode sequences derived from expert identified reference specimens in order to determine the identity and aid invasion pathway analysis of the non-indigenous species found in North America using DNA barcodes. Sequences were obtained from 121 tissue samples representing 25 species and combined with public records from GenBank for a total of 36 putative species, which then partitioned into 49 discrete haplogroups. Multiple divergent clusters were observed within C. gachua, C. marulius, C. punctata and C. striata suggesting the potential presence of cryptic species diversity within these lineages. Our findings demonstrate that DNA barcoding is a valuable tool for species identification in challenging and under-studied taxonomic groups such as snakeheads, and provides a useful framework for inferring invasion pathway analysis.

  19. Calibrating Snakehead Diversity with DNA Barcodes: Expanding Taxonomic Coverage to Enable Identification of Potential and Established Invasive Species

    PubMed Central

    Serrao, Natasha R.; Steinke, Dirk; Hanner, Robert H.

    2014-01-01

    Detecting and documenting the occurrence of invasive species outside their native range requires tools to support their identification. This can be challenging for taxa with diverse life stages and/or problematic or unresolved morphological taxonomies. DNA barcoding provides a potent method for identifying invasive species, as it allows for species identification at all life stages, including fragmentary remains. It also provides an efficient interim taxonomic framework for quantifying cryptic genetic diversity by parsing barcode sequences into discontinuous haplogroup clusters (typical of reproductively isolated species) and labelling them with unique alphanumeric identifiers. Snakehead fishes are a diverse group of opportunistic predators endemic to Asia and Africa that may potentially pose significant threats as aquatic invasive species. At least three snakehead species (Channa argus, C. maculata, and C. marulius) are thought to have entered North America through the aquarium and live-food fish markets, and have established populations, yet their origins remain unclear. The objectives of this study were to assemble a library of DNA barcode sequences derived from expert identified reference specimens in order to determine the identity and aid invasion pathway analysis of the non-indigenous species found in North America using DNA barcodes. Sequences were obtained from 121 tissue samples representing 25 species and combined with public records from GenBank for a total of 36 putative species, which then partitioned into 49 discrete haplogroups. Multiple divergent clusters were observed within C. gachua, C. marulius, C. punctata and C. striata suggesting the potential presence of cryptic species diversity within these lineages. Our findings demonstrate that DNA barcoding is a valuable tool for species identification in challenging and under-studied taxonomic groups such as snakeheads, and provides a useful framework for inferring invasion pathway analysis. PMID

  20. Calibrating snakehead diversity with DNA barcodes: expanding taxonomic coverage to enable identification of potential and established invasive species.

    PubMed

    Serrao, Natasha R; Steinke, Dirk; Hanner, Robert H

    2014-01-01

    Detecting and documenting the occurrence of invasive species outside their native range requires tools to support their identification. This can be challenging for taxa with diverse life stages and/or problematic or unresolved morphological taxonomies. DNA barcoding provides a potent method for identifying invasive species, as it allows for species identification at all life stages, including fragmentary remains. It also provides an efficient interim taxonomic framework for quantifying cryptic genetic diversity by parsing barcode sequences into discontinuous haplogroup clusters (typical of reproductively isolated species) and labelling them with unique alphanumeric identifiers. Snakehead fishes are a diverse group of opportunistic predators endemic to Asia and Africa that may potentially pose significant threats as aquatic invasive species. At least three snakehead species (Channa argus, C. maculata, and C. marulius) are thought to have entered North America through the aquarium and live-food fish markets, and have established populations, yet their origins remain unclear. The objectives of this study were to assemble a library of DNA barcode sequences derived from expert identified reference specimens in order to determine the identity and aid invasion pathway analysis of the non-indigenous species found in North America using DNA barcodes. Sequences were obtained from 121 tissue samples representing 25 species and combined with public records from GenBank for a total of 36 putative species, which then partitioned into 49 discrete haplogroups. Multiple divergent clusters were observed within C. gachua, C. marulius, C. punctata and C. striata suggesting the potential presence of cryptic species diversity within these lineages. Our findings demonstrate that DNA barcoding is a valuable tool for species identification in challenging and under-studied taxonomic groups such as snakeheads, and provides a useful framework for inferring invasion pathway analysis. PMID

  1. Nutrient enrichment induces dormancy and decreases diversity of active bacteria in salt marsh sediments

    PubMed Central

    Kearns, Patrick J.; Angell, John H.; Howard, Evan M.; Deegan, Linda A.; Stanley, Rachel H. R.; Bowen, Jennifer L.

    2016-01-01

    Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that control the proportion of active microbes in the environment and how they vary when perturbed is critical to anticipating ecosystem response to global change. Increasing supplies of anthropogenic nitrogen to ecosystems globally makes it imperative that we understand how nutrient supply alters active microbial communities. Here we show that nitrogen additions to salt marshes cause a shift in the active microbial community despite no change in the total community. The active community shift causes the proportion of dormant microbial taxa to double, from 45 to 90%, and induces diversity loss in the active portion of the community. Our results suggest that perturbations to salt marshes can drastically alter active microbial communities, however these communities may remain resilient by protecting total diversity through increased dormancy. PMID:27666199

  2. Nutrient enrichment induces dormancy and decreases diversity of active bacteria in salt marsh sediments

    NASA Astrophysics Data System (ADS)

    Kearns, Patrick J.; Angell, John H.; Howard, Evan M.; Deegan, Linda A.; Stanley, Rachel H. R.; Bowen, Jennifer L.

    2016-09-01

    Microorganisms control key biogeochemical pathways, thus changes in microbial diversity, community structure and activity can affect ecosystem response to environmental drivers. Understanding factors that control the proportion of active microbes in the environment and how they vary when perturbed is critical to anticipating ecosystem response to global change. Increasing supplies of anthropogenic nitrogen to ecosystems globally makes it imperative that we understand how nutrient supply alters active microbial communities. Here we show that nitrogen additions to salt marshes cause a shift in the active microbial community despite no change in the total community. The active community shift causes the proportion of dormant microbial taxa to double, from 45 to 90%, and induces diversity loss in the active portion of the community. Our results suggest that perturbations to salt marshes can drastically alter active microbial communities, however these communities may remain resilient by protecting total diversity through increased dormancy.

  3. Low Genetic Diversity and High Invasion Success of Corbicula fluminea (Bivalvia, Corbiculidae) (Müller, 1774) in Portugal

    PubMed Central

    Gomes, Cidália; Sousa, Ronaldo; Mendes, Tito; Borges, Rui; Vilares, Pedro; Vasconcelos, Vitor; Guilhermino, Lúcia; Antunes, Agostinho

    2016-01-01

    The Asian clam, Corbicula fluminea, is an invasive alien species (IAS) originally from Asia that has spread worldwide causing major ecological and economic impacts in aquatic ecosystems. Here, we evaluated C. fluminea genetic (using COI mtDNA, CYTb mtDNA and 18S rDNA gene markers), morphometric and sperm morphology variation in Portuguese freshwater ecosystems. The COI marker revealed a single haplotype, which belongs to the Asian FW5 invasive lineage, suggesting a common origin for all the 13 Portuguese C. fluminea populations analysed. Morphometric analyses showed differences between the populations colonizing the North (with the exception of the Lima River) and the Centre/South ecosystems. The sperm morphology examination revealed the presence of biflagellate sperm, a distinctive character of the invasive androgenetic lineages. The low genetic variability of the Portuguese C. fluminea populations and the pattern of sperm morphology have been illuminating for understanding the demographic history of this invasive species. We hypothesize that these populations were derived from a unique introductory event of a Corbicula fluminea FW5 invasive androgenic lineage in the Tejo River, which subsequently dispersed to other Portuguese freshwater ecosystems. The C. fluminea asexual reproductive mode may have assisted these populations to become highly invasive despite the low genetic diversity. PMID:27391333

  4. Low Genetic Diversity and High Invasion Success of Corbicula fluminea (Bivalvia, Corbiculidae) (Müller, 1774) in Portugal.

    PubMed

    Gomes, Cidália; Sousa, Ronaldo; Mendes, Tito; Borges, Rui; Vilares, Pedro; Vasconcelos, Vitor; Guilhermino, Lúcia; Antunes, Agostinho

    2016-01-01

    The Asian clam, Corbicula fluminea, is an invasive alien species (IAS) originally from Asia that has spread worldwide causing major ecological and economic impacts in aquatic ecosystems. Here, we evaluated C. fluminea genetic (using COI mtDNA, CYTb mtDNA and 18S rDNA gene markers), morphometric and sperm morphology variation in Portuguese freshwater ecosystems. The COI marker revealed a single haplotype, which belongs to the Asian FW5 invasive lineage, suggesting a common origin for all the 13 Portuguese C. fluminea populations analysed. Morphometric analyses showed differences between the populations colonizing the North (with the exception of the Lima River) and the Centre/South ecosystems. The sperm morphology examination revealed the presence of biflagellate sperm, a distinctive character of the invasive androgenetic lineages. The low genetic variability of the Portuguese C. fluminea populations and the pattern of sperm morphology have been illuminating for understanding the demographic history of this invasive species. We hypothesize that these populations were derived from a unique introductory event of a Corbicula fluminea FW5 invasive androgenic lineage in the Tejo River, which subsequently dispersed to other Portuguese freshwater ecosystems. The C. fluminea asexual reproductive mode may have assisted these populations to become highly invasive despite the low genetic diversity. PMID:27391333

  5. Heavy metal pollution decreases microbial abundance, diversity and activity within particle-size fractions of a paddy soil.

    PubMed

    Chen, Junhui; He, Feng; Zhang, Xuhui; Sun, Xuan; Zheng, Jufeng; Zheng, Jinwei

    2014-01-01

    Chemical and microbial characterisations of particle-size fractions (PSFs) from a rice paddy soil subjected to long-term heavy metal pollution (P) and nonpolluted (NP) soil were performed to investigate whether the distribution of heavy metals (Cd, Cu, Pb and Zn) regulates microbial community activity, abundance and diversity at the microenvironment scale. The soils were physically fractionated into coarse sand, fine sand, silt and clay fractions. Long-term heavy metal pollution notably decreased soil basal respiration (a measurement of the total activity of the soil microbial community) and microbial biomass carbon (MBC) across the fractions by 3-45% and 21-53%, respectively. The coarse sand fraction was more affected by pollution than the clay fraction and displayed a significantly lower MBC content and respiration and dehydrogenase activity compared with the nonpolluted soils. The abundances and diversities of bacteria were less affected within the PSFs under pollution. However, significant decreases in the abundances and diversities of fungi were noted, which may have strongly contributed to the decrease in MBC. Sequencing of denaturing gradient gel electrophoresis bands revealed that the groups Acidobacteria, Ascomycota and Chytridiomycota were clearly inhibited under pollution. Our findings suggest that long-term heavy metal pollution decreased the microbial biomass, activity and diversity in PSFs, particularly in the large-size fractions.

  6. Diversity of mycorrhizal fungi of terrestrial orchids: compatibility webs, brief encounters, lasting relationships and alien invasions.

    PubMed

    Bonnardeaux, Yumiko; Brundrett, Mark; Batty, Andrew; Dixon, Kingsley; Koch, John; Sivasithamparam, K

    2007-01-01

    The diversity of mycorrhizal fungi associated with an introduced weed-like South African orchid (Disa bracteata) and a disturbance-intolerant, widespread, native West Australian orchid (Pyrorchis nigricans) were compared by molecular identification of the fungi isolated from single pelotons. Molecular identification revealed both orchids were associated with fungi from diverse groups in the Rhizoctonia complex with worldwide distribution. Symbiotic germination assays confirmed the majority of fungi isolated from pelotons were mycorrhizal and a factorial experiment uncovered complex webs of compatibility between six terrestrial orchids and 12 fungi from Australia and South Africa. Two weed-like (disturbance-tolerant rapidly spreading) orchids - D. bracteata and the indigenous Australian Microtis media, had the broadest webs of mycorrhizal fungi. In contrast, other native orchids had relatively small webs of fungi (Diuris magnifica and Thelymitra crinita), or germinated exclusively with their own fungus (Caladenia falcata and Pterostylis sanguinea). Orchids, such as D. bracteata and M. media, which form relationships with diverse webs of fungi, had apparent specificity that decreased with time, as some fungi had brief encounters with orchids that supported protocorm formation but not subsequent seedling growth. The interactions between orchid mycorrhizal fungi and their hosts are discussed.

  7. Increased Inter-Colony Fusion Rates Are Associated with Reduced COI Haplotype Diversity in an Invasive Colonial Ascidian Didemnum vexillum

    PubMed Central

    Smith, Kirsty F.; Stefaniak, Lauren; Saito, Yasunori; Gemmill, Chrissen E. C.; Cary, S. Craig; Fidler, Andrew E.

    2012-01-01

    Considerable progress in our understanding of the population genetic changes associated with biological invasions has been made over the past decade. Using selectively neutral loci, it has been established that reductions in genetic diversity, reflecting founder effects, have occurred during the establishment of some invasive populations. However, some colonial organisms may actually gain an ecological advantage from reduced genetic diversity because of the associated reduction in inter-colony conflict. Here we report population genetic analyses, along with colony fusion experiments, for a highly invasive colonial ascidian, Didemnum vexillum. Analyses based on mitochondrial cytochrome oxidase I (COI) partial coding sequences revealed two distinct D. vexillum clades. One COI clade appears to be restricted to the probable native region (i.e., north-west Pacific Ocean), while the other clade is present in widely dispersed temperate coastal waters around the world. This clade structure was supported by 18S ribosomal DNA (rDNA) sequence data, which revealed a one base-pair difference between the two clades. Recently established populations of D. vexillum in New Zealand displayed greatly reduced COI genetic diversity when compared with D. vexillum in Japan. In association with this reduction in genetic diversity was a significantly higher inter-colony fusion rate between randomly paired New Zealand D. vexillum colonies (80%, standard deviation ±18%) when compared with colonies found in Japan (27%, standard deviation ±15%). The results of this study add to growing evidence that for colonial organisms reductions in population level genetic diversity may alter colony interaction dynamics and enhance the invasive potential of newly colonizing species. PMID:22303442

  8. Temporal analysis of mtDNA variation reveals decreased genetic diversity in least terns

    USGS Publications Warehouse

    Draheim, Hope M.; Baird, Patricia; Haig, Susan M.

    2012-01-01

    The Least Tern (Sternula antillarum) has undergone large population declines over the last century as a result of direct and indirect anthropogenic factors. The genetic implications of these declines are unknown. We used historical museum specimens (pre-1960) and contemporary (2001–2005) samples to examine range-wide phylogeographic patterns and investigate potential loss in the species' genetic variation. We obtained sequences (522 bp) of the mitochondrial gene for NADH dehydrogenase subunit 6 (ND6) from 268 individuals from across the species' range. Phylogeographic analysis revealed no association with geography or traditional subspecies designations. However, we detected potential reductions in genetic diversity in contemporary samples from California and the Atlantic coast Least Tern from that in historical samples, suggesting that current genetic diversity in Least Tern populations is lower than in their pre-1960 counterparts. Our results offer unique insights into changes in the Least Tern's genetic diversity over the past century and highlight the importance and utility of museum specimens in studies of conservation genetics.

  9. Decreased fish diversity found near marble industry effluents in River Barandu, Pakistan.

    PubMed

    Mulk, Shahi; Korai, Abdul Latif; Azizullah, Azizullah; Khattak, Muhammad Nasir Khan

    2016-01-01

    In a recently published study we observed that effluents from marble industry affected physicochemical characteristics of River Barandu in District Buner, Pakistan. These changes in water quality due to marble effluents may affect fish community. The present study was therefore conducted to evaluate the impacts of marble industry effluents on fish communities in River Barandu using abundance, richness, diversity and evenness of fish species as end point criteria. The fish samples were collected by local fishermen on monthly basis from three selected sites (upstream, effluents/industrial, and downstream sites). During the study period, a total of 18 fish species were found belonging to 4 orders, 5 families and 11 genera. The Cyprinidae was observed to be the dominant family at all the three selected sites. Lower abundance and species diversity was observed at the industrial (22%) and downstream sites (33%) as compared to the upstream site (45%). Effluents of marble industry were associated with lower abundance of species in River Barandu. It is recommended that industries should be shifted away from the vicinity of river and their effluents must be treated before discharging to prevent further loss of fish abundance and diversity in the River.

  10. Ecosystem engineering by invasive exotic beavers reduces in-stream diversity and enhances ecosystem function in Cape Horn, Chile.

    PubMed

    Anderson, Christopher B; Rosemond, Amy D

    2007-11-01

    Species invasions are of global significance, but predicting their impacts can be difficult. Introduced ecosystem engineers, however, provide an opportunity to test the underlying mechanisms that may be common to all invasive engineers and link relationships between changes in diversity and ecosystem function, thereby providing explanatory power for observed ecological patterns. Here we test specific predictions for an invasive ecosystem engineer by quantifying the impacts of habitat and resource modifications caused by North American beavers (Castor canadensis) on aquatic macroinvertebrate community structure and stream ecosystem function in the Cape Horn Biosphere Reserve, Chile. We compared responses to beavers in three habitat types: (1) forested (unimpacted) stream reaches, (2) beaver ponds, and (3) sites immediately downstream of beaver dams in four streams. We found that beaver engineering in ponds created taxonomically simplified, but more productive, benthic macroinvertebrate assemblages. Specifically, macroinvertebrate richness, diversity and number of functional feeding groups were reduced by half, while abundance, biomass and secondary production increased three- to fivefold in beaver ponds compared to forested sites. Reaches downstream of beaver ponds were very similar to natural forested sections. Beaver invasion effects on both community and ecosystem parameters occurred predominantly via increased retention of fine particulate organic matter, which was associated with reduced macroinvertebrate richness and diversity (via homogenization of benthic microhabitat) and increased macroinvertebrate biomass and production (via greater food availability). Beaver modifications to macroinvertebrate community structure were largely confined to ponds, but increased benthic production in beaver-modified habitats adds to energy retention and flow for the entire stream ecosystem. Furthermore, the effects of beavers on taxa richness (negative) and measures of

  11. Plant invasions differentially affected by diversity and dominant species in native- and exotic-dominated grasslands.

    PubMed

    Xu, Xia; Polley, H Wayne; Hofmockel, Kirsten; Daneshgar, Pedram P; Wilsey, Brian J

    2015-12-01

    Plant invasions are an increasingly serious global concern, especially as the climate changes. Here, we explored how plant invasions differed between native- and novel exotic-dominated grasslands with experimental addition of summer precipitation in Texas in 2009. Exotic species greened up earlier than natives by an average of 18 days. This was associated with a lower invasion rate early in the growing season compared to native communities. However, invasion rate did not differ significantly between native and exotic communities across all sampling times. The predictors of invasion rate differed between native and exotic communities, with invasion being negatively influenced by species richness in natives and by dominant species in exotics. Interestingly, plant invasions matched the bimodal pattern of precipitation in Temple, Texas, and did not respond to the pulse of precipitation during the summer. Our results suggest that we will need to take different approaches in understanding of invasion between native and exotic grasslands. Moreover, with anticipated increasing variability in precipitation under global climate change, plant invasions may be constrained in their response if the precipitation pulses fall outside the normal growing period of invaders.

  12. Plant invasions differentially affected by diversity and dominant species in native- and exotic-dominated grasslands.

    PubMed

    Xu, Xia; Polley, H Wayne; Hofmockel, Kirsten; Daneshgar, Pedram P; Wilsey, Brian J

    2015-12-01

    Plant invasions are an increasingly serious global concern, especially as the climate changes. Here, we explored how plant invasions differed between native- and novel exotic-dominated grasslands with experimental addition of summer precipitation in Texas in 2009. Exotic species greened up earlier than natives by an average of 18 days. This was associated with a lower invasion rate early in the growing season compared to native communities. However, invasion rate did not differ significantly between native and exotic communities across all sampling times. The predictors of invasion rate differed between native and exotic communities, with invasion being negatively influenced by species richness in natives and by dominant species in exotics. Interestingly, plant invasions matched the bimodal pattern of precipitation in Temple, Texas, and did not respond to the pulse of precipitation during the summer. Our results suggest that we will need to take different approaches in understanding of invasion between native and exotic grasslands. Moreover, with anticipated increasing variability in precipitation under global climate change, plant invasions may be constrained in their response if the precipitation pulses fall outside the normal growing period of invaders. PMID:27069615

  13. Benthic community responses to macroalgae invasions in seagrass beds: Diversity, isotopic niche and food web structure at community level

    NASA Astrophysics Data System (ADS)

    Deudero, S.; Box, A.; Vázquez-Luis, M.; Arroyo, N. L.

    2014-04-01

    Trophic paths between species are a useful tool for analysing the impact of species invasions of a biotic community. Species invasions produce changes at trophic level and diversity shifts by replacing native species with species of similar ecological niche. This study focused on the effects of macroalgal invasions on seagrass ecosystems. We conducted two - year bimonthly sampling of a pristine Posidonia oceanica seagrass meadow and dead matte colonized by three Caulerpa species bimonthly. The largest changes in faunal composition were found in meadows colonized by Caulerpa prolifera, where major differences in infaunal taxonomic distinctness were apparent. On the other hand, the infaunal community was quite similar between the two invasive Caulerpa species (Caulerpa taxifolia and Caulerpa racemosa). The isotopic niche based on the main trophic guilds established using stable isotope signatures at community level resulted in a highly compacted and 15N-enriched C. prolifera food web structure, indicating high overlap of food source utilization among faunal components, which is typical of degraded systems. Conversely, the P. oceanica ecosystem presented the most complex food web, while the influence of the 2 invasive species were similar. An attempt to reconstruct the food web at each vegetated habitat revealed high trophic linkages among the different trophic levels with a continuous transition among them by the various trophic guilds suggesting an adaptation response of the different organisms to the new habitat forming species.

  14. Habitat Loss other than Fragmentation per se Decreased Nuclear and Chloroplast Genetic Diversity in a Monoecious Tree

    PubMed Central

    Shen, Dong-Wei; Chen, Xiao-Yong

    2012-01-01

    Generally, effect of fragmentation per se on biodiversity has not been separated from the effect of habitat loss. In this paper, using nDNA and cpDNA SSRs, we studied genetic diversity of Castanopsis sclerophylla (Lindl. & Paxton) Schotty populations and decoupled the effects of habitat loss and fragmentation per se. We selected seven nuclear and six cpDNA microsatellite loci and genotyped 460 individuals from mainland and island populations, which were located in the impoundment created in 1959. Number of alleles per locus of populations in larger habitats was significantly higher than that in smaller habitats. There was a significant relationship between the number of alleles per locus and habitat size. Based on this relationship, the predicted genetic diversity of an imaginary population of size equaling the total area of the islands was lower than that of the global population on the islands. Re-sampling demonstrated that low genetic diversity of populations in small habitats was caused by unevenness in sample size. Fisher's α index was similar among habitat types. These results indicate that the decreased nuclear and chloroplast genetic diversity of populations in smaller habitats was mainly caused by habitat loss. For nuclear and chloroplast microsatellite loci, values of FST were 0.066 and 0.893, respectively, and the calculated pollen/seed dispersal ratio was 162.2. When separated into pre-and post-fragmentation cohorts, pollen/seed ratios were 121.2 and 189.5, respectively. Our results suggest that habitat loss explains the early decrease in genetic diversity, while fragmentation per se may play a major role in inbreeding and differentiation among fragmented populations and later loss of genetic diversity. PMID:22723951

  15. Habitat loss other than fragmentation per se decreased nuclear and chloroplast genetic diversity in a monoecious tree.

    PubMed

    Zhang, Xin; Shi, Miao-Miao; Shen, Dong-Wei; Chen, Xiao-Yong

    2012-01-01

    Generally, effect of fragmentation per se on biodiversity has not been separated from the effect of habitat loss. In this paper, using nDNA and cpDNA SSRs, we studied genetic diversity of Castanopsis sclerophylla (Lindl. & Paxton) Schotty populations and decoupled the effects of habitat loss and fragmentation per se. We selected seven nuclear and six cpDNA microsatellite loci and genotyped 460 individuals from mainland and island populations, which were located in the impoundment created in 1959. Number of alleles per locus of populations in larger habitats was significantly higher than that in smaller habitats. There was a significant relationship between the number of alleles per locus and habitat size. Based on this relationship, the predicted genetic diversity of an imaginary population of size equaling the total area of the islands was lower than that of the global population on the islands. Re-sampling demonstrated that low genetic diversity of populations in small habitats was caused by unevenness in sample size. Fisher's α index was similar among habitat types. These results indicate that the decreased nuclear and chloroplast genetic diversity of populations in smaller habitats was mainly caused by habitat loss. For nuclear and chloroplast microsatellite loci, values of F(ST) were 0.066 and 0.893, respectively, and the calculated pollen/seed dispersal ratio was 162.2. When separated into pre-and post-fragmentation cohorts, pollen/seed ratios were 121.2 and 189.5, respectively. Our results suggest that habitat loss explains the early decrease in genetic diversity, while fragmentation per se may play a major role in inbreeding and differentiation among fragmented populations and later loss of genetic diversity. PMID:22723951

  16. Habitat loss other than fragmentation per se decreased nuclear and chloroplast genetic diversity in a monoecious tree.

    PubMed

    Zhang, Xin; Shi, Miao-Miao; Shen, Dong-Wei; Chen, Xiao-Yong

    2012-01-01

    Generally, effect of fragmentation per se on biodiversity has not been separated from the effect of habitat loss. In this paper, using nDNA and cpDNA SSRs, we studied genetic diversity of Castanopsis sclerophylla (Lindl. & Paxton) Schotty populations and decoupled the effects of habitat loss and fragmentation per se. We selected seven nuclear and six cpDNA microsatellite loci and genotyped 460 individuals from mainland and island populations, which were located in the impoundment created in 1959. Number of alleles per locus of populations in larger habitats was significantly higher than that in smaller habitats. There was a significant relationship between the number of alleles per locus and habitat size. Based on this relationship, the predicted genetic diversity of an imaginary population of size equaling the total area of the islands was lower than that of the global population on the islands. Re-sampling demonstrated that low genetic diversity of populations in small habitats was caused by unevenness in sample size. Fisher's α index was similar among habitat types. These results indicate that the decreased nuclear and chloroplast genetic diversity of populations in smaller habitats was mainly caused by habitat loss. For nuclear and chloroplast microsatellite loci, values of F(ST) were 0.066 and 0.893, respectively, and the calculated pollen/seed dispersal ratio was 162.2. When separated into pre-and post-fragmentation cohorts, pollen/seed ratios were 121.2 and 189.5, respectively. Our results suggest that habitat loss explains the early decrease in genetic diversity, while fragmentation per se may play a major role in inbreeding and differentiation among fragmented populations and later loss of genetic diversity.

  17. Landscape corridors can increase invasion by an exotic species and reduce diversity of native species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although corridors have become commonplace in conservation to mitigate negative effects of habitat fragmentation, concerns persist that they may facilitate spread of invasive species. In a large-scale experiment, we measured effects of corridors on invasive fire ants, Solenopsis invicta, and on comm...

  18. Plant invasions differentially affected by diversity and dominant species in native- and exotic-dominated grasslands

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Precipitation is anticipated to vary greatly under global climate change. However, little is known about the role of precipitation in shaping weed invasion of established grassland ecosystems. Here, we explored how weed invasion was influenced by precipitation and how this pattern was modified by ...

  19. Nitrogen deposition and management practices increase soil microbial biomass carbon but decrease diversity in Moso bamboo plantations

    NASA Astrophysics Data System (ADS)

    Li, Quan; Song, Xinzhang; Gu, Honghao; Gao, Fei

    2016-06-01

    Because microbial communities play a key role in carbon (C) and nitrogen (N) cycling, changes in the soil microbial community may directly affect ecosystem functioning. However, the effects of N deposition and management practices on soil microbes are still poorly understood. We studied the effects of these two factors on soil microbial biomass carbon (MBC) and community composition in Moso bamboo plantations using high-throughput sequencing of the 16S rRNA gene. Plantations under conventional (CM) or intensive management (IM) were subjected to one of four N treatments for 30 months. IM and N addition, both separately and in combination, significantly increased soil MBC while decreasing bacterial diversity. However, increases in soil MBC were inhibited when N addition exceeded 60 kg N•ha‑1•yr‑1. IM increased the relative abundances of Actinobacteria and Crenarchaeota but decreased that of Acidobacteria. N addition increased the relative abundances of Acidobacteria, Crenarchaeota, and Actinobacteria but decreased that of Proteobacteria. Soil bacterial diversity was significantly related to soil pH, C/N ratio, and nitrogen and available phosphorus content. Management practices exerted a greater influence over regulation of the soil MBC and microbial diversity compared to that of N deposition in Moso bamboo plantations.

  20. Nitrogen deposition and management practices increase soil microbial biomass carbon but decrease diversity in Moso bamboo plantations

    PubMed Central

    Li, Quan; Song, Xinzhang; Gu, Honghao; Gao, Fei

    2016-01-01

    Because microbial communities play a key role in carbon (C) and nitrogen (N) cycling, changes in the soil microbial community may directly affect ecosystem functioning. However, the effects of N deposition and management practices on soil microbes are still poorly understood. We studied the effects of these two factors on soil microbial biomass carbon (MBC) and community composition in Moso bamboo plantations using high-throughput sequencing of the 16S rRNA gene. Plantations under conventional (CM) or intensive management (IM) were subjected to one of four N treatments for 30 months. IM and N addition, both separately and in combination, significantly increased soil MBC while decreasing bacterial diversity. However, increases in soil MBC were inhibited when N addition exceeded 60 kg N∙ha−1∙yr−1. IM increased the relative abundances of Actinobacteria and Crenarchaeota but decreased that of Acidobacteria. N addition increased the relative abundances of Acidobacteria, Crenarchaeota, and Actinobacteria but decreased that of Proteobacteria. Soil bacterial diversity was significantly related to soil pH, C/N ratio, and nitrogen and available phosphorus content. Management practices exerted a greater influence over regulation of the soil MBC and microbial diversity compared to that of N deposition in Moso bamboo plantations. PMID:27302857

  1. French invasive Asian tiger mosquito populations harbor reduced bacterial microbiota and genetic diversity compared to Vietnamese autochthonous relatives

    PubMed Central

    Minard, G.; Tran, F. H.; Van, Van Tran; Goubert, C.; Bellet, C.; Lambert, G.; Kim, Khanh Ly Huynh; Thuy, Trang Huynh Thi; Mavingui, P.; Valiente Moro, C.

    2015-01-01

    The Asian tiger mosquito Aedes albopictus is one of the most significant pathogen vectors of the twenty-first century. Originating from Asia, it has invaded a wide range of eco-climatic regions worldwide. The insect-associated microbiota is now recognized to play a significant role in host biology. While genetic diversity bottlenecks are known to result from biological invasions, the resulting shifts in host-associated microbiota diversity has not been thoroughly investigated. To address this subject, we compared four autochthonous Ae. albopictus populations in Vietnam, the native area of Ae. albopictus, and three populations recently introduced to Metropolitan France, with the aim of documenting whether these populations display differences in host genotype and bacterial microbiota. Population-level genetic diversity (microsatellite markers and COI haplotype) and bacterial diversity (16S rDNA metabarcoding) were compared between field-caught mosquitoes. Bacterial microbiota from the whole insect bodies were largely dominated by Wolbachia pipientis. Targeted analysis of the gut microbiota revealed a greater bacterial diversity in which a fraction was common between French and Vietnamese populations. The genus Dysgonomonas was the most prevalent and abundant across all studied populations. Overall genetic diversities of both hosts and bacterial microbiota were significantly reduced in recently established populations of France compared to the autochthonous populations of Vietnam. These results open up many important avenues of investigation in order to link the process of geographical invasion to shifts in commensal and symbiotic microbiome communities, as such shifts may have dramatic impacts on the biology and/or vector competence of invading hematophagous insects. PMID:26441903

  2. Decreased microbial diversity and Lactobacillus group in the intestine of geriatric giant pandas (Ailuropoda melanoleuca).

    PubMed

    Peng, Zhirong; Zeng, Dong; Wang, Qiang; Niu, Lili; Ni, Xueqin; Zou, Fuqin; Yang, Mingyue; Sun, Hao; Zhou, Yi; Liu, Qian; Yin, Zhongqiong; Pan, Kangcheng; Jing, Bo

    2016-05-01

    It has been established beyond doubt that giant panda genome lacks lignin-degrading related enzyme, gastrointestinal microbes may play a vital role in digestion of highly fibrous bamboo diet. However, there is not much information available about the intestinal bacteria composition in captive giant pandas with different ages. In this study, we compared the intestinal bacterial community of 12 captive giant pandas from three different age groups (subadults, adults, and geriatrics) through PCR-denaturing gradient gel electrophoresis (DGGE) and real-time PCR analysis. Results indicated that microbial diversity in the intestine of adults was significantly higher than that of the geriatrics (p < 0.05), but not significant compared to the subadults (p > 0.05). The predominant bands in DGGE patterns shared by the twelve pandas were related to Firmicutes and Proteobacteria. Additionally, in comparison to healthy individuals, antibiotic-treated animals showed partial microbial dysbiosis. Real-time PCR analyses confirmed a significantly higher abundance of the Lactobacillus in the fecal microbiota of adults (p < 0.05), while other bacterial groups and species detected did not significantly differ among the three age groups (p > 0.05). This study revealed that captive giant pandas with different ages showed different intestinal bacteria composition. PMID:27038949

  3. Decreased microbial diversity and Lactobacillus group in the intestine of geriatric giant pandas (Ailuropoda melanoleuca).

    PubMed

    Peng, Zhirong; Zeng, Dong; Wang, Qiang; Niu, Lili; Ni, Xueqin; Zou, Fuqin; Yang, Mingyue; Sun, Hao; Zhou, Yi; Liu, Qian; Yin, Zhongqiong; Pan, Kangcheng; Jing, Bo

    2016-05-01

    It has been established beyond doubt that giant panda genome lacks lignin-degrading related enzyme, gastrointestinal microbes may play a vital role in digestion of highly fibrous bamboo diet. However, there is not much information available about the intestinal bacteria composition in captive giant pandas with different ages. In this study, we compared the intestinal bacterial community of 12 captive giant pandas from three different age groups (subadults, adults, and geriatrics) through PCR-denaturing gradient gel electrophoresis (DGGE) and real-time PCR analysis. Results indicated that microbial diversity in the intestine of adults was significantly higher than that of the geriatrics (p < 0.05), but not significant compared to the subadults (p > 0.05). The predominant bands in DGGE patterns shared by the twelve pandas were related to Firmicutes and Proteobacteria. Additionally, in comparison to healthy individuals, antibiotic-treated animals showed partial microbial dysbiosis. Real-time PCR analyses confirmed a significantly higher abundance of the Lactobacillus in the fecal microbiota of adults (p < 0.05), while other bacterial groups and species detected did not significantly differ among the three age groups (p > 0.05). This study revealed that captive giant pandas with different ages showed different intestinal bacteria composition.

  4. Patterns of genetic diversity reveal multiple introductions and recurrent founder effects during range expansion in invasive populations of Geranium carolinianum (Geraniaceae).

    PubMed

    Shirk, R Y; Hamrick, J L; Zhang, C; Qiang, S

    2014-05-01

    Genetic diversity, and thus the adaptive potential of invasive populations, is largely based on three factors: patterns of genetic diversity in the species' native range, the number and location of introductions and the number of founding individuals per introduction. Specifically, reductions in genetic diversity ('founder effects') should be stronger for species with low within-population diversity in their native range and few introductions of few individuals to the invasive range. We test these predictions with Geranium carolinianum, a winter annual herb native to North America and invasive in China. We measure the extent of founder effects using allozymes and microsatellites, and ask whether this is consistent with its colonization history and patterns of diversity in the native range. In the native range, genetic diversity is higher and structure is lower than expected based on life history traits. In China, our results provide evidence for multiple introductions near Nanjing, Jiangsu province, with subsequent range expansion to the west and south. Patterns of genetic diversity across China reveal weak founder effects that are driven largely by low-diversity populations at the expansion front, away from the introduction location. This suggests that reduced diversity in China has resulted from successive founder events during range expansion, and that the loss of genetic diversity in the Nanjing area was mitigated by multiple introductions from diverse source populations. This has implications for the future of G. carolinianum in China, as continued gene flow among populations should eventually increase genetic diversity within the more recently founded populations.

  5. Rhamnus cathartica (Rosales: Rhamnaceae) Invasion Reduces Ground-Dwelling Insect Abundance and Diversity in Northeast Iowa Forests.

    PubMed

    Schuh, Marissa; Larsen, Kirk J

    2015-06-01

    European buckthorn (Rhamnus cathartica L.) is an invasive woody shrub in deciduous forests of the Upper Midwest. Studies have suggested buckthorn invasion has negative effects on native plants, soil, and ecosystems, but its impacts on insects are largely unstudied. To test the impact of buckthorn invasion on ground-dwelling insects in forests of northeastern Iowa, pitfall traps were used to sample ground-dwelling insects at five sites four different periods from June to August 2013. Each site had three treatments: areas heavily infested with buckthorn, areas where buckthorn has not established, and areas where buckthorn had been removed within the past 2-10 yr. Most insects were identified to family and quantified; while ground beetles (Coleoptera: Carabidae) and ants (Hymenoptera: Formicidae) were identified to species and quantified. In total, 11,576 insects representing eight orders and 46 families were collected. Areas uninvaded by buckthorn had significantly greater insect abundance and taxonomic richness than areas invaded by buckthorn. Of the 948 ground beetles representing 40 species, abundance, species richness, and Shannon diversity indices were significantly lower in areas invaded by buckthorn compared with areas with no buckthorn. The 2,661 ants from 24 species had similar trends, but treatment differences were not significant because of high variability. These results clearly show a negative impact of buckthorn invasion on the abundance and taxonomic richness of ground-dwelling insects.

  6. Rhamnus cathartica (Rosales: Rhamnaceae) Invasion Reduces Ground-Dwelling Insect Abundance and Diversity in Northeast Iowa Forests.

    PubMed

    Schuh, Marissa; Larsen, Kirk J

    2015-06-01

    European buckthorn (Rhamnus cathartica L.) is an invasive woody shrub in deciduous forests of the Upper Midwest. Studies have suggested buckthorn invasion has negative effects on native plants, soil, and ecosystems, but its impacts on insects are largely unstudied. To test the impact of buckthorn invasion on ground-dwelling insects in forests of northeastern Iowa, pitfall traps were used to sample ground-dwelling insects at five sites four different periods from June to August 2013. Each site had three treatments: areas heavily infested with buckthorn, areas where buckthorn has not established, and areas where buckthorn had been removed within the past 2-10 yr. Most insects were identified to family and quantified; while ground beetles (Coleoptera: Carabidae) and ants (Hymenoptera: Formicidae) were identified to species and quantified. In total, 11,576 insects representing eight orders and 46 families were collected. Areas uninvaded by buckthorn had significantly greater insect abundance and taxonomic richness than areas invaded by buckthorn. Of the 948 ground beetles representing 40 species, abundance, species richness, and Shannon diversity indices were significantly lower in areas invaded by buckthorn compared with areas with no buckthorn. The 2,661 ants from 24 species had similar trends, but treatment differences were not significant because of high variability. These results clearly show a negative impact of buckthorn invasion on the abundance and taxonomic richness of ground-dwelling insects. PMID:26313971

  7. Plant Invasions Associated with Change in Root-Zone Microbial Community Structure and Diversity.

    PubMed

    Rodrigues, Richard R; Pineda, Rosana P; Barney, Jacob N; Nilsen, Erik T; Barrett, John E; Williams, Mark A

    2015-01-01

    The importance of plant-microbe associations for the invasion of plant species have not been often tested under field conditions. The research sought to determine patterns of change in microbial communities associated with the establishment of invasive plants with different taxonomic and phenetic traits. Three independent locations in Virginia, USA were selected. One site was invaded by a grass (Microstegium vimineum), another by a shrub (Rhamnus davurica), and the third by a tree (Ailanthus altissima). The native vegetation from these sites was used as reference. 16S rRNA and ITS regions were sequenced to study root-zone bacterial and fungal communities, respectively, in invaded and non-invaded samples and analyzed using Quantitative Insights Into Microbial Ecology (QIIME). Though root-zone microbial community structure initially differed across locations, plant invasion shifted communities in similar ways. Indicator species analysis revealed that Operational Taxonomic Units (OTUs) closely related to Proteobacteria, Acidobacteria, Actinobacteria, and Ascomycota increased in abundance due to plant invasions. The Hyphomonadaceae family in the Rhodobacterales order and ammonia-oxidizing Nitrospirae phylum showed greater relative abundance in the invaded root-zone soils. Hyphomicrobiaceae, another bacterial family within the phyla Proteobacteria increased as a result of plant invasion, but the effect associated most strongly with root-zones of M. vimineum and R. davurica. Functional analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) showed bacteria responsible for nitrogen cycling in soil increased in relative abundance in association with plant invasion. In agreement with phylogenetic and functional analyses, greater turnover of ammonium and nitrate was associated with plant invasion. Overall, bacterial and fungal communities changed congruently across plant invaders, and support the hypothesis that nitrogen

  8. Plant Invasions Associated with Change in Root-Zone Microbial Community Structure and Diversity.

    PubMed

    Rodrigues, Richard R; Pineda, Rosana P; Barney, Jacob N; Nilsen, Erik T; Barrett, John E; Williams, Mark A

    2015-01-01

    The importance of plant-microbe associations for the invasion of plant species have not been often tested under field conditions. The research sought to determine patterns of change in microbial communities associated with the establishment of invasive plants with different taxonomic and phenetic traits. Three independent locations in Virginia, USA were selected. One site was invaded by a grass (Microstegium vimineum), another by a shrub (Rhamnus davurica), and the third by a tree (Ailanthus altissima). The native vegetation from these sites was used as reference. 16S rRNA and ITS regions were sequenced to study root-zone bacterial and fungal communities, respectively, in invaded and non-invaded samples and analyzed using Quantitative Insights Into Microbial Ecology (QIIME). Though root-zone microbial community structure initially differed across locations, plant invasion shifted communities in similar ways. Indicator species analysis revealed that Operational Taxonomic Units (OTUs) closely related to Proteobacteria, Acidobacteria, Actinobacteria, and Ascomycota increased in abundance due to plant invasions. The Hyphomonadaceae family in the Rhodobacterales order and ammonia-oxidizing Nitrospirae phylum showed greater relative abundance in the invaded root-zone soils. Hyphomicrobiaceae, another bacterial family within the phyla Proteobacteria increased as a result of plant invasion, but the effect associated most strongly with root-zones of M. vimineum and R. davurica. Functional analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) showed bacteria responsible for nitrogen cycling in soil increased in relative abundance in association with plant invasion. In agreement with phylogenetic and functional analyses, greater turnover of ammonium and nitrate was associated with plant invasion. Overall, bacterial and fungal communities changed congruently across plant invaders, and support the hypothesis that nitrogen

  9. Plant Invasions Associated with Change in Root-Zone Microbial Community Structure and Diversity

    PubMed Central

    Rodrigues, Richard R.; Pineda, Rosana P.; Barney, Jacob N.; Nilsen, Erik T.; Barrett, John E.; Williams, Mark A.

    2015-01-01

    The importance of plant-microbe associations for the invasion of plant species have not been often tested under field conditions. The research sought to determine patterns of change in microbial communities associated with the establishment of invasive plants with different taxonomic and phenetic traits. Three independent locations in Virginia, USA were selected. One site was invaded by a grass (Microstegium vimineum), another by a shrub (Rhamnus davurica), and the third by a tree (Ailanthus altissima). The native vegetation from these sites was used as reference. 16S rRNA and ITS regions were sequenced to study root-zone bacterial and fungal communities, respectively, in invaded and non-invaded samples and analyzed using Quantitative Insights Into Microbial Ecology (QIIME). Though root-zone microbial community structure initially differed across locations, plant invasion shifted communities in similar ways. Indicator species analysis revealed that Operational Taxonomic Units (OTUs) closely related to Proteobacteria, Acidobacteria, Actinobacteria, and Ascomycota increased in abundance due to plant invasions. The Hyphomonadaceae family in the Rhodobacterales order and ammonia-oxidizing Nitrospirae phylum showed greater relative abundance in the invaded root-zone soils. Hyphomicrobiaceae, another bacterial family within the phyla Proteobacteria increased as a result of plant invasion, but the effect associated most strongly with root-zones of M. vimineum and R. davurica. Functional analysis using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States (PICRUSt) showed bacteria responsible for nitrogen cycling in soil increased in relative abundance in association with plant invasion. In agreement with phylogenetic and functional analyses, greater turnover of ammonium and nitrate was associated with plant invasion. Overall, bacterial and fungal communities changed congruently across plant invaders, and support the hypothesis that nitrogen

  10. Naringenin decreases invasiveness and metastasis by inhibiting TGF-β-induced epithelial to mesenchymal transition in pancreatic cancer cells.

    PubMed

    Lou, Changjie; Zhang, Fayun; Yang, Ming; Zhao, Juan; Zeng, Wenfeng; Fang, Xiaocui; Zhang, Yanqiao; Zhang, Chunling; Liang, Wei

    2012-01-01

    Epithelial to mesenchymal transition (EMT) promotes cellular motility, invasiveness and metastasis during embryonic development and tumorigenesis. Transforming growth factor-β (TGF-β) signaling pathway is a key regulator of EMT. A lot of evidences suggest that this process is Smad3-dependent. Herein we showed that exposure of aspc-1 and panc-1 pancreatic cancer cells to TGF-β1 resulted in characteristic morphological alterations of EMT, and enhancement of cell motility and gemcitabine (Gem) resistance along with an up-regulation of EMT markers genes such as vimentin, N-cadherin, MMP2 and MMP9. Naringenin (Nar) down-regulated EMT markers expression in both mRNA and protein levels by inhibiting TGF-β1/Smad3 signal pathway in the pancreatic cancer cells. Consequently, Nar suppressed the cells migration and invasion and reversed their resistance to Gem. PMID:23300530

  11. Shared genetic diversity across the global invasive range of the monk parakeet suggests a common restricted geographic origin and the possibility of convergent selection.

    PubMed

    Edelaar, Pim; Roques, Severine; Hobson, Elizabeth A; Gonçalves da Silva, Anders; Avery, Michael L; Russello, Michael A; Senar, Juan C; Wright, Timothy F; Carrete, Martina; Tella, José L

    2015-05-01

    While genetic diversity is hypothesized to be an important factor explaining invasion success, there is no consensus yet on how variation in source populations or demographic processes affects invasiveness. We used mitochondrial DNA haplotypic and microsatellite genotypic data to investigate levels of genetic variation and reconstruct the history of replicate invasions on three continents in a globally invasive bird, the monk parakeet (Myiopsitta monachus). We evaluated whether genetic diversity at invasive sites could be explained by (i) the native source populations from which they were derived and (ii) demographic bottlenecks during introduction. Genetic data indicated a localized source area for most sampled invasive populations, with limited evidence for admixing of native source populations. This pattern largely coincides with historical data on pet trade exports. However, the invasive populations are genetically more similar than predicted from the export data alone. The extent of bottleneck effects varied among invasive populations. The observed low genetic diversity, evidence of demographic contraction and restricted source area do not support the hypothesis that invasion is favoured by the mixing and recombining of genetic variation from multiple source populations. Instead, they suggest that reduced genetic variation through random processes may not inhibit successful establishment and invasion in this species. However, convergent selection across invasive sites could also explain the observed patterns of reduction and similarity in genetic variation and/or the restricted source area. In general, the alternative explanation of intraspecific variation in invasive potential among genotypes or geographic areas is neglected, but warrants more attention as it could inform comparative studies and management of biological invaders.

  12. Inhibition of microRNA-21 decreases the invasiveness of fibroblast-like synoviocytes in rheumatoid arthritis via TGFβ/Smads signaling pathway

    PubMed Central

    Xiong, Gaoxin; Huang, Zhang; Jiang, Hua; Pan, Zhengjun; Xie, Jie; Wang, Shuangli

    2016-01-01

    Objective(s): MicroRNA-21 (miR21) is aberrantly elevated in rheumatoid arthritis (RA) patients, the significance of this microRNA in RA pathogenesis and treatment, however, has not been investigated. In this study, by using RA-derived fibroblast-like synoviocyte (FLS) cells as a model, we investigated the effect and corresponding mechanism of miR21 inhibition on FLSs invasion. Materials and Methods: miR21 expression in synovial tissue and FLSs in RA patients and non-RA controls were determined by stem-loop RT-PCR. The effect of miR21 on FLSs viability and invasiveness were evaluated using miR21 inhibition. Cell viability was evaluated by MTT assay and the expression of genes at mRNA and protein levels was determined by RT-PCR and Western blot, respectively. Results: Our results showed that miR21 expression was highly increased in synovial tissue and FLSs in RA patients. Also, we reported that miR21 inhibitor treatment could significantly suppress the invasiveness of FLSs without affecting cell viability. The decreased FLSs invasion by miR21 inhibition was associated with down-regulated expression of matrix metalloproteinase (MMP)-1, MMP3, and MMP13. Further analysis revealed that miR21 inhibition could suppress the expression of TGFβ1 and Smad4, but promote that of Smad7. Moreover, suppression of FLS invasion and MMPs expression by miR21 treatment could be counteracted by additional TGFβ1 treatment. Conclusion: Our results indicated that miR21 inhibition can down-regulate the expression of MMP1, MMP3, and MMP13 and consequently suppress the invasiveness of FLS, which is achieved through TGFβ1/Smad4/7 signaling pathway. The findings of this study could offer a novel approach for RA treatment. PMID:27635204

  13. Ecosystem-phase interactions: aquatic eutrophication decreases terrestrial plant diversity in California vernal pools.

    PubMed

    Kneitel, Jamie M; Lessin, Carrie L

    2010-06-01

    Eutrophication has long been known to negatively affect aquatic and terrestrial ecosystems worldwide. In freshwater ecosystems, excessive nutrient input results in a shift from vascular plant dominance to algal dominance, while the nutrient-species richness relationship is found to be unimodal. Eutrophication studies are usually conducted in continuously aquatic or terrestrial habitats, but it is unclear how these patterns may be altered by temporal heterogeneity driven by precipitation and temperature variation. The California vernal pool (CVP) ecosystem consists of three distinct phases (aquatic, terrestrial, and dry) caused by variation in climatic conditions. The purpose of this study was to test the hypothesis that resource addition during the aquatic phase results in increased algal abundance, which reduces vascular plant cover and richness of the terrestrial phase upon desiccation. We used mesocosms layered with CVP soil, in which treatments consisted of five levels of nitrogen and phosphorous added every 2 weeks. Resource addition increased available phosphorus levels and algae cover during the aquatic phase. Increased algal crusts resulted in decreased vascular plant percent cover and species richness. Few significant patterns were observed with individual plant species and total biomass. The phosphorus-plant richness relationship was not significant, but species composition was significantly different among the low and high treatment comparisons. These results highlight a neglected effect of eutrophication in seasonal habitats. Interactions among ecosystem phases clearly require more attention empirically and theoretically. Management and restoration of temporally heterogeneous habitat, such as the endemic-rich CVP, need to consider the extensive effects of increased nutrient input. PMID:20012097

  14. Invasion of Ligustrum lucidum (Oleaceae) in the southern Yungas: Changes in habitat properties and decline in bird diversity

    NASA Astrophysics Data System (ADS)

    Ayup, M. M.; Montti, L.; Aragón, R.; Grau, H. R.

    2014-01-01

    Ligustrum lucidum is the major exotic tree in NW Argentina montane forests (Yungas). To assess the effects of its expanding invasion on avian communities we (1) measured different habitat properties (vertical forest structure and composition, vegetation cover, light availability, air temperature, air relative humidity and soil litter depth), (2) compared bird species composition and diversity in Ligustrum-dominated and native-dominated secondary forests and (3) analyzed seasonal patterns and changes in these variables between forest types. The study was conducted during 2010-2011 wet and dry seasons, at two altitudinal zones: 500-800 and 1100-1450 masl. Compared with native forests, Ligustrum dominated forests had a more homogeneous vertical forest structure and denser canopy cover (resulting in lower understory solar radiation), significantly lower understory cover and lower litter depth. Air temperature and relative humidity did not differ between forests in either season. Solar radiation was higher in the dry season in both forest types, but litter depth showed opposite patterns between seasons depending on forest type. We recorded 59 bird species in 21 families. Bird species abundance, richness and diversity indexes were significantly lower in Ligustrum-dominated relative to native forests of similar successional age, which had almost twice as many species as the former. Avian communities differed between altitudinal zones, but the difference was stronger between Ligustrum and native-dominated forests. Avian community composition was less variable in time and space in native forests than in Ligustrum-dominated ones. Our results suggest that L. lucidum invasion generates structurally homogeneous and simpler forests that represent a less suitable habitat for a diverse avifauna. This illustrates the wide ecological changes (from habitat properties and ecosystem functioning to vertebrate community composition) that the subtropical mountain forests of Argentina are

  15. Non-thermal plasma inhibits human cervical cancer HeLa cells invasiveness by suppressing the MAPK pathway and decreasing matrix metalloproteinase-9 expression

    NASA Astrophysics Data System (ADS)

    Li, Wei; Yu, K. N.; Bao, Lingzhi; Shen, Jie; Cheng, Cheng; Han, Wei

    2016-01-01

    Non-thermal plasma (NTP) has been proposed as a novel therapeutic method for anticancer treatment. However, the mechanism underlying its biological effects remains unclear. In this study, we investigated the inhibitory effect of NTP on the invasion of HeLa cells, and explored the possible mechanism. Our results showed that NTP exposure for 20 or 40 s significantly suppressed the migration and invasion of HeLa cells on the basis of matrigel invasion assay and wound healing assay, respectively. Moreover, NTP reduced the activity and protein expression of the matrix metalloproteinase (MMP)-9 enzyme. Western blot analysis indicated that NTP exposure effectively decreased phosphorylation level of both ERK1/2 and JNK, but not p38 MAPK. Furthermore, treatment with MAPK signal pathway inhibitors or NTP all exhibited significant depression of HeLa cells migration and MMP-9 expression. The result showed that NTP synergistically suppressed migration and MMP-9 expression in the presence of ERK1/2 inhibitor and JNK inhibitor, but not p38 MAPK inhibitor. Taken together, these findings suggested that NTP exposure inhibited the migration and invasion of HeLa cells via down-regulating MMP-9 expression in ERK1/2 and JNK signaling pathways dependent manner. These findings provide hints to the potential clinical research and therapy of NTP on cervical cancer metastasis.

  16. Genomic Recombination Leading to Decreased Virulence of Group B Streptococcus in a Mouse Model of Adult Invasive Disease

    PubMed Central

    Teatero, Sarah; Lemire, Paul; Dewar, Ken; Wasserscheid, Jessica; Calzas, Cynthia; Mallo, Gustavo V.; Li, Aimin; Athey, Taryn B.T.; Segura, Mariela; Fittipaldi, Nahuel

    2016-01-01

    Adult invasive disease caused by Group B Streptococcus (GBS) is increasing worldwide. Whole-genome sequencing (WGS) now permits rapid identification of recombination events, a phenomenon that occurs frequently in GBS. Using WGS, we described that strain NGBS375, a capsular serotype V GBS isolate of sequence type (ST)297, has an ST1 genomic background but has acquired approximately 300 kbp of genetic material likely from an ST17 strain. Here, we examined the virulence of this strain in an in vivo model of GBS adult invasive infection. The mosaic ST297 strain showed intermediate virulence, causing significantly less systemic infection and reduced mortality than a more virulent, serotype V ST1 isolate. Bacteremia induced by the ST297 strain was similar to that induced by a serotype III ST17 strain, which was the least virulent under the conditions tested. Yet, under normalized bacteremia levels, the in vivo intrinsic capacity to induce the production of pro-inflammatory cytokines was similar between the ST297 strain and the virulent ST1 strain. Thus, the diminished virulence of the mosaic strain may be due to reduced capacity to disseminate or multiply in blood during a systemic infection which could be mediated by regulatory factors contained in the recombined region. PMID:27527222

  17. Long live the alien: is high genetic diversity a pivotal aspect of crested porcupine (Hystrix cristata) long-lasting and successful invasion?

    PubMed

    Trucchi, Emiliano; Facon, Benoit; Gratton, Paolo; Mori, Emiliano; Stenseth, Nils Chr; Jentoft, Sissel

    2016-08-01

    Studying the evolutionary dynamics of an alien species surviving and continuing to expand after several generations can provide fundamental information on the relevant features of clearly successful invasions. Here, we tackle this task by investigating the dynamics of the genetic diversity in invasive crested porcupine (Hystrix cristata) populations, introduced to Italy about 1500 years ago, which are still growing in size, distribution range and ecological niche. Using genome-wide RAD markers, we describe the structure of the genetic diversity and the demographic dynamics of the H. cristata invasive populations and compare their genetic diversity with that of native African populations of both H. cristata and its sister species, H. africaeaustralis. First, we demonstrate that genetic diversity is lower in both the invasive Italian and the North Africa source range relative to other native populations from sub-Saharan and South Africa. Second, we find evidence of multiple introduction events in the invasive range followed by very limited gene flow. Through coalescence-based demographic reconstructions, we also show that the bottleneck at introduction was mild and did not affect the introduced genetic diversity. Finally, we reveal that the current spatial expansion at the northern boundary of the range is following a leading-edge model characterized by a general reduction of genetic diversity towards the edge of the expanding range. We conclude that the level of genome-wide diversity of H. cristata invasive populations is less important in explaining its successful invasion than species-specific life-history traits or the phylogeographic history in the native source range. PMID:27171527

  18. Long live the alien: is high genetic diversity a pivotal aspect of crested porcupine (Hystrix cristata) long-lasting and successful invasion?

    PubMed

    Trucchi, Emiliano; Facon, Benoit; Gratton, Paolo; Mori, Emiliano; Stenseth, Nils Chr; Jentoft, Sissel

    2016-08-01

    Studying the evolutionary dynamics of an alien species surviving and continuing to expand after several generations can provide fundamental information on the relevant features of clearly successful invasions. Here, we tackle this task by investigating the dynamics of the genetic diversity in invasive crested porcupine (Hystrix cristata) populations, introduced to Italy about 1500 years ago, which are still growing in size, distribution range and ecological niche. Using genome-wide RAD markers, we describe the structure of the genetic diversity and the demographic dynamics of the H. cristata invasive populations and compare their genetic diversity with that of native African populations of both H. cristata and its sister species, H. africaeaustralis. First, we demonstrate that genetic diversity is lower in both the invasive Italian and the North Africa source range relative to other native populations from sub-Saharan and South Africa. Second, we find evidence of multiple introduction events in the invasive range followed by very limited gene flow. Through coalescence-based demographic reconstructions, we also show that the bottleneck at introduction was mild and did not affect the introduced genetic diversity. Finally, we reveal that the current spatial expansion at the northern boundary of the range is following a leading-edge model characterized by a general reduction of genetic diversity towards the edge of the expanding range. We conclude that the level of genome-wide diversity of H. cristata invasive populations is less important in explaining its successful invasion than species-specific life-history traits or the phylogeographic history in the native source range.

  19. Phylogenetic investigation of the genus Raoiella (Prostigmata: Tenuipalpidae): Diversity, distribution, and world invasions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The genus Raoiella is most well known because of the red palm mite, R. indica, a major pest of palms spreading aggressively throughout the Americas. Not much was known about the biology, geographic origins, or evolutionary history of the genus when R. indica emerged as a major invasive pest. This pa...

  20. Forest species diversity reduces disease risk in a generalist plant pathogen invasion

    USGS Publications Warehouse

    Haas, Sarah E.; Hooten, Mevin B.; Rizzo, David M.; Meentemeyer, Ross K.

    2011-01-01

    Empirical evidence suggests that biodiversity loss can increase disease transmission, yet our understanding of the 'diversity-disease hypothesis' for generalist pathogens in natural ecosystems is limited. We used a landscape epidemiological approach to examine two scenarios regarding diversity effects on the emerging plant pathogen Phytophthora ramorum across a broad, heterogeneous ecoregion: (1) an amplification effect exists where disease risk is greater in areas with higher plant diversity due to the pathogen's wide host range, or (2) a dilution effect where risk is reduced with increasing diversity due to lower competency of alternative hosts. We found evidence for pathogen dilution, whereby disease risk was lower in sites with higher species diversity, after accounting for potentially confounding effects of host density and landscape heterogeneity. Our results suggest that although nearly all plants in the ecosystem are hosts, alternative hosts may dilute disease transmission by competent hosts, thereby buffering forest health from infectious disease.

  1. Invasive stink bug favors naïve plants: Testing the role of plant geographic origin in diverse, managed environments.

    PubMed

    Martinson, Holly M; Bergmann, Erik J; Venugopal, P Dilip; Riley, Christopher B; Shrewsbury, Paula M; Raupp, Michael J

    2016-01-01

    With the introduction and establishment of exotic species, most ecosystems now contain both native and exotic plants and herbivores. Recent research identifies several factors that govern how specialist herbivores switch host plants upon introduction. Predicting the feeding ecology and impacts of introduced generalist species, however, remains difficult. Here, we examine how plant geographic origin, an indicator of shared co-evolutionary history, influences patterns of host use by a generalist, invasive herbivore, while accounting for variation in plant availability. The brown marmorated stink bug, Halyomorpha halys, is a highly polyphagous Asian herbivore and an economically important invasive pest in North America and Europe. In visual surveys of 220 plant taxa in commercial nurseries in Maryland, USA, H. halys was more abundant on non-Asian plants and selected these over Asian plants. The relationship between the relative use of plants and their availability was strongly positive but depended also on plant origin at two of our three sites, where the higher relative use of non-Asian plants was greatest for highly abundant taxa. These results highlight the importance of considering both plant origin and relative abundance in understanding the selection of host plants by invasive generalist herbivores in diverse, natural and urban forests. PMID:27581756

  2. Invasive stink bug favors naïve plants: Testing the role of plant geographic origin in diverse, managed environments

    PubMed Central

    Martinson, Holly M.; Bergmann, Erik J.; Venugopal, P. Dilip; Riley, Christopher B.; Shrewsbury, Paula M.; Raupp, Michael J.

    2016-01-01

    With the introduction and establishment of exotic species, most ecosystems now contain both native and exotic plants and herbivores. Recent research identifies several factors that govern how specialist herbivores switch host plants upon introduction. Predicting the feeding ecology and impacts of introduced generalist species, however, remains difficult. Here, we examine how plant geographic origin, an indicator of shared co-evolutionary history, influences patterns of host use by a generalist, invasive herbivore, while accounting for variation in plant availability. The brown marmorated stink bug, Halyomorpha halys, is a highly polyphagous Asian herbivore and an economically important invasive pest in North America and Europe. In visual surveys of 220 plant taxa in commercial nurseries in Maryland, USA, H. halys was more abundant on non-Asian plants and selected these over Asian plants. The relationship between the relative use of plants and their availability was strongly positive but depended also on plant origin at two of our three sites, where the higher relative use of non-Asian plants was greatest for highly abundant taxa. These results highlight the importance of considering both plant origin and relative abundance in understanding the selection of host plants by invasive generalist herbivores in diverse, natural and urban forests. PMID:27581756

  3. Invasive stink bug favors naïve plants: Testing the role of plant geographic origin in diverse, managed environments.

    PubMed

    Martinson, Holly M; Bergmann, Erik J; Venugopal, P Dilip; Riley, Christopher B; Shrewsbury, Paula M; Raupp, Michael J

    2016-09-01

    With the introduction and establishment of exotic species, most ecosystems now contain both native and exotic plants and herbivores. Recent research identifies several factors that govern how specialist herbivores switch host plants upon introduction. Predicting the feeding ecology and impacts of introduced generalist species, however, remains difficult. Here, we examine how plant geographic origin, an indicator of shared co-evolutionary history, influences patterns of host use by a generalist, invasive herbivore, while accounting for variation in plant availability. The brown marmorated stink bug, Halyomorpha halys, is a highly polyphagous Asian herbivore and an economically important invasive pest in North America and Europe. In visual surveys of 220 plant taxa in commercial nurseries in Maryland, USA, H. halys was more abundant on non-Asian plants and selected these over Asian plants. The relationship between the relative use of plants and their availability was strongly positive but depended also on plant origin at two of our three sites, where the higher relative use of non-Asian plants was greatest for highly abundant taxa. These results highlight the importance of considering both plant origin and relative abundance in understanding the selection of host plants by invasive generalist herbivores in diverse, natural and urban forests.

  4. Prolactin receptor attenuation induces zinc pool redistribution through ZnT2 and decreases invasion in MDA-MB-453 breast cancer cells

    SciTech Connect

    Bostanci, Zeynep; Alam, Samina; Soybel, David I.; Kelleher, Shannon L.

    2014-02-15

    Prolactin receptor (PRL-R) activation regulates cell differentiation, proliferation, cell survival and motility of breast cells. Prolactin (PRL) and PRL-R over-expression are strongly implicated in breast cancer, particularly contributing to tumor growth and invasion in the more aggressive estrogen-receptor negative (ER−) disease. PRL-R antagonists have been suggested as potential therapeutic agents; however, mechanisms through which PRL-R antagonists exert their actions are not well-understood. Zinc (Zn) is a regulatory factor for over 10% of the proteome, regulating critical cell processes such as proliferation, cell signaling, transcription, apoptosis and autophagy. PRL-R signaling regulates Zn metabolism in breast cells. Herein we determined effects of PRL-R attenuation on cellular Zn metabolism and cell function in a model of ER-, PRL-R over-expressing breast cancer cells (MDA-MB-453). PRL-R attenuation post-transcriptionally increased ZnT2 abundance and redistributed intracellular Zn pools into lysosomes and mitochondria. ZnT2-mediated lysosomal Zn sequestration was associated with reduced matrix metalloproteinase 2 (MMP-2) activity and decreased invasion. ZnT2-mediated Zn accumulation in mitochondria was associated with increased mitochondrial oxidation. Our results suggest that PRL-R antagonism in PRL-R over-expressing breast cancer cells may reduce invasion through the redistribution of intracellular Zn pools critical for cellular function. - Highlights: • PRL-R attenuation increased ZnT2 expression. • PRL-R attenuation increased lysosomal and mitochondrial Zn accumulation. • PRL-R attenuation decreased MMP-2 and invasion. • PRL-R antagonists may modulate lysosomal and mitochondrial Zn pools.

  5. High genetic diversity in French invasive populations of common ragweed, Ambrosia artemisiifolia, as a result of multiple sources of introduction.

    PubMed

    Genton, B J; Shykoff, J A; Giraud, T

    2005-12-01

    Ambrosia artemisiifolia is an aggressive North American annual weed, found particularly in sunflower and corn fields. Besides its economic impact on crop yield, it represents a major health problem because of its strongly allergenic pollen. Ragweed was imported inadvertently to Europe in the 18th century and has become invasive in several countries, notably in the Rhône Valley of France. It has recently expanded in both the Provence-Alpes-Côte-d'Azur and Bourgogne regions. As first steps towards understanding the causes and mechanisms of ragweed invasion, genetic variability of French and North American populations was analysed using microsatellites. Overall genetic variability was similar in North America and in the Rhône-Alpes region, but within-population levels of genetic variability were surprisingly lower in native than in invasive French populations. French populations also exhibited lower among-population differentiation. A significant pattern of isolation by distance was detected among North American populations but not among French populations. Assignment tests and distribution of rare alleles did not point to a single origin for all French populations, nor for all individuals within populations and private alleles from different North American populations were found in the same French populations. Indeed, within all French populations, individual plants were roughly equally assigned to the different North American populations. Altogether, these results suggest that the French invasive populations include plants from a mixture of sources. Reduced diversity in populations distant from the original area of introduction indicated that ragweed range expansion probably occurred through sequential bottlenecks from the original populations, and not from subsequent new introductions.

  6. Indigenous and Invasive Fruit Fly Diversity along an Altitudinal Transect in Eastern Central Tanzania

    PubMed Central

    Geurts, Katrien; Mwatawala, Maulid; De Meyer, Marc

    2012-01-01

    The relative abundance of indigenous and invasive frugivorous fruit flies (Diptera: Tephritidae) was evaluated spatially and temporally along an altitudinal transect between 581–1650 m in the Uluguru Mountains near Morogoro, Tanzania. The polyphagous invasive fruit fly Bactrocera invadens Drew, Tsuruta, and White and the indigenous fruit fly Ceratitis rosa Karsch show a similar temporal pattern, but are largely separated spatially, with B. invadens being abundant at lower elevation and C. rosa predominant at higher elevation. The polyphagous indigenous C. cosyra (Walker) coincides with B. invadens but shows an inverse temporal pattern. The cucurbit feeders B. cucurbitae (Coquillett) and Dacus bivittatus (Bigot) show a similar temporal pattern, but the former is restricted to lower elevations. Host availability and climatic differences seem to be the determining factors to explain the differences in occurrence and abundance in time and space. PMID:22935017

  7. Decreased small mammal and on-host tick abundance in association with invasive red imported fire ants (Solenopsis invicta).

    PubMed

    Castellanos, Adrian A; Medeiros, Matthew C I; Hamer, Gabriel L; Morrow, Michael E; Eubanks, Micky D; Teel, Pete D; Hamer, Sarah A; Light, Jessica E

    2016-09-01

    Invasive species may impact pathogen transmission by altering the distributions and interactions among native vertebrate reservoir hosts and arthropod vectors. Here, we examined the direct and indirect effects of the red imported fire ant (Solenopsis invicta) on the native tick, small mammal and pathogen community in southeast Texas. Using a replicated large-scale field manipulation study, we show that small mammals were more abundant on treatment plots where S. invicta populations were experimentally reduced. Our analysis of ticks on small mammal hosts demonstrated a threefold increase in the ticks caught per unit effort on treatment relative to control plots, and elevated tick loads (a 27-fold increase) on one common rodent species. We detected only one known human pathogen (Rickettsia parkeri), present in 1.4% of larvae and 6.7% of nymph on-host Amblyomma maculatum samples but with no significant difference between treatment and control plots. Given that host and vector population dynamics are key drivers of pathogen transmission, the reduced small mammal and tick abundance associated with S. invicta may alter pathogen transmission dynamics over broader spatial scales. PMID:27651533

  8. Decreased small mammal and on-host tick abundance in association with invasive red imported fire ants (Solenopsis invicta)

    PubMed Central

    Medeiros, Matthew C. I.; Hamer, Gabriel L.; Morrow, Michael E.; Eubanks, Micky D.; Teel, Pete D.

    2016-01-01

    Invasive species may impact pathogen transmission by altering the distributions and interactions among native vertebrate reservoir hosts and arthropod vectors. Here, we examined the direct and indirect effects of the red imported fire ant (Solenopsis invicta) on the native tick, small mammal and pathogen community in southeast Texas. Using a replicated large-scale field manipulation study, we show that small mammals were more abundant on treatment plots where S. invicta populations were experimentally reduced. Our analysis of ticks on small mammal hosts demonstrated a threefold increase in the ticks caught per unit effort on treatment relative to control plots, and elevated tick loads (a 27-fold increase) on one common rodent species. We detected only one known human pathogen (Rickettsia parkeri), present in 1.4% of larvae and 6.7% of nymph on-host Amblyomma maculatum samples but with no significant difference between treatment and control plots. Given that host and vector population dynamics are key drivers of pathogen transmission, the reduced small mammal and tick abundance associated with S. invicta may alter pathogen transmission dynamics over broader spatial scales. PMID:27651533

  9. Decreased small mammal and on-host tick abundance in association with invasive red imported fire ants (Solenopsis invicta).

    PubMed

    Castellanos, Adrian A; Medeiros, Matthew C I; Hamer, Gabriel L; Morrow, Michael E; Eubanks, Micky D; Teel, Pete D; Hamer, Sarah A; Light, Jessica E

    2016-09-01

    Invasive species may impact pathogen transmission by altering the distributions and interactions among native vertebrate reservoir hosts and arthropod vectors. Here, we examined the direct and indirect effects of the red imported fire ant (Solenopsis invicta) on the native tick, small mammal and pathogen community in southeast Texas. Using a replicated large-scale field manipulation study, we show that small mammals were more abundant on treatment plots where S. invicta populations were experimentally reduced. Our analysis of ticks on small mammal hosts demonstrated a threefold increase in the ticks caught per unit effort on treatment relative to control plots, and elevated tick loads (a 27-fold increase) on one common rodent species. We detected only one known human pathogen (Rickettsia parkeri), present in 1.4% of larvae and 6.7% of nymph on-host Amblyomma maculatum samples but with no significant difference between treatment and control plots. Given that host and vector population dynamics are key drivers of pathogen transmission, the reduced small mammal and tick abundance associated with S. invicta may alter pathogen transmission dynamics over broader spatial scales.

  10. Decreasing Abundance, Increasing Diversity and Changing Structure of the Wild Bee Community (Hymenoptera: Anthophila) along an Urbanization Gradient

    PubMed Central

    Fortel, Laura; Henry, Mickaël; Guilbaud, Laurent; Guirao, Anne Laure; Kuhlmann, Michael; Mouret, Hugues; Rollin, Orianne; Vaissière, Bernard E.

    2014-01-01

    Background Wild bees are important pollinators that have declined in diversity and abundance during the last decades. Habitat destruction and fragmentation associated with urbanization are reported as part of the main causes of this decline. Urbanization involves dramatic changes of the landscape, increasing the proportion of impervious surface while decreasing that of green areas. Few studies have investigated the effects of urbanization on bee communities. We assessed changes in the abundance, species richness, and composition of wild bee community along an urbanization gradient. Methodology/Principal Findings Over two years and on a monthly basis, bees were sampled with colored pan traps and insect nets at 24 sites located along an urbanization gradient. Landscape structure within three different radii was measured at each study site. We captured 291 wild bee species. The abundance of wild bees was negatively correlated with the proportion of impervious surface, while species richness reached a maximum at an intermediate (50%) proportion of impervious surface. The structure of the community changed along the urbanization gradient with more parasitic species in sites with an intermediate proportion of impervious surface. There were also greater numbers of cavity-nesting species and long-tongued species in sites with intermediate or higher proportion of impervious surface. However, urbanization had no effect on the occurrence of species depending on their social behavior or body size. Conclusions/Significance We found nearly a third of the wild bee fauna known from France in our study sites. Indeed, urban areas supported a diverse bee community, but sites with an intermediate level of urbanization were the most speciose ones, including greater proportion of parasitic species. The presence of a diverse array of bee species even in the most urbanized area makes these pollinators worthy of being a flagship group to raise the awareness of urban citizens about

  11. Low temperature decreases the phylogenetic diversity of ammonia-oxidizing archaea and bacteria in aquarium biofiltration systems.

    PubMed

    Urakawa, Hidetoshi; Tajima, Yoshiyuki; Numata, Yoshiyuki; Tsuneda, Satoshi

    2008-02-01

    The phylogenetic diversity and species richness of ammonia-oxidizing archaea (AOA) and bacteria (AOB) were examined with aquarium biofiltration systems. Species richness, deduced from rarefaction analysis, and diversity indices indicated that the phylogenetic diversity and species richness of AOA are greater than those of AOB; the diversity of AOA and of AOB is minimized in cold-water aquaria. This finding implies that temperature is a key factor influencing the population structure and diversity of AOA and AOB in aquarium biofiltration systems.

  12. AB209630, a long non-coding RNA decreased expression in hypopharyngeal squamous cell carcinoma, influences proliferation, invasion, metastasis, and survival

    PubMed Central

    Li, Wenming; Wang, Juan; Xiang, Xuan; Li, Guojun; Pan, Xinliang; Lei, Dapeng

    2016-01-01

    Long noncoding RNAs (lncRNAs) are associated with the development, progression, and prognosis of human cancers. However, the clinical significance and biological function of lncRNAs in hypopharyngeal squamous cell carcinoma (HSCC) remain largely unknown. We characterized the novel lncRNA AB209630 in vivo and in vitro. First, using qRT-PCR, we evaluated whether AB209630 levels differ between HSCC tissues/cell lines and adjacent normal tissues/cell lines. We then assessed whether AB209630 expression levels stimulate or inhibit proliferation, invasion, apoptosis, and metastasis in vitro. Finally, we investigated whether AB209630 levels in tumor tissues were associated with survival outcomes. Our results demonstrated that AB209630 levels were markedly lower in HSCC tissues and cells than in normal tissues and cells, and increased expression of AB209630 level significantly inhibited growth, metastasis, and invasion and stimulated apoptosis in vitro. In addition, patients with decreased expression of AB209630 had a significantly poorer prognosis than those with high AB209630 expression. These data suggest that increased expression of AB209630 might either stimulate or inhibit biological activities involved in HSCC development, indicating a potential application of AB209630 in future treatment for this disease. This study suggest that AB209630 functions as a tumor suppressor in HSCC, and its decreased expression may help predict a poor prognostic outcome of HSCC. Our future work will focus on the mechanisms of whether and how AB209630 as a tumor suppressor gene is involved in HSCC development. PMID:26895099

  13. Phylogenetic investigation of the genus Raoiella (Prostigmata: Tenuipalpidae): diversity, distribution, and world invasions.

    PubMed

    Dowling, A P G; Ochoa, R; Beard, J J; Welbourn, W C; Ueckermann, E A

    2012-08-01

    The genus Raoiella is best known because of the red palm mite, R. indica, a major pest of palms spreading aggressively throughout the Americas. Not much was known about the biology, geographic origins, or evolutionary history of the genus when R. indica emerged as a major invasive pest. This paper attempts to address some of the basic historical questions regarding the palm mite as well as the genus. Molecular characters from COI and 28S regions were used to produce a phylogenetic hypothesis for the genus in an effort to understand its geographic origin. It also uses COI barcode data to delimit several potentially new species discovered by the authors in Australia. Results show a basal split between R. indica and all other Raoiella species, which indicates Africa or the Middle East as the most probable origin of the genus. Additionally, COI data suggests that at least eight new species are represented among the 20 Australian populations included in this study.

  14. Phylogenetic investigation of the genus Raoiella (Prostigmata: Tenuipalpidae): diversity, distribution, and world invasions.

    PubMed

    Dowling, A P G; Ochoa, R; Beard, J J; Welbourn, W C; Ueckermann, E A

    2012-08-01

    The genus Raoiella is best known because of the red palm mite, R. indica, a major pest of palms spreading aggressively throughout the Americas. Not much was known about the biology, geographic origins, or evolutionary history of the genus when R. indica emerged as a major invasive pest. This paper attempts to address some of the basic historical questions regarding the palm mite as well as the genus. Molecular characters from COI and 28S regions were used to produce a phylogenetic hypothesis for the genus in an effort to understand its geographic origin. It also uses COI barcode data to delimit several potentially new species discovered by the authors in Australia. Results show a basal split between R. indica and all other Raoiella species, which indicates Africa or the Middle East as the most probable origin of the genus. Additionally, COI data suggests that at least eight new species are represented among the 20 Australian populations included in this study. PMID:21913003

  15. The Relative Importance of Genetic Diversity and Phenotypic Plasticity in Determining Invasion Success of a Clonal Weed in the USA and China.

    PubMed

    Geng, Yupeng; van Klinken, Rieks D; Sosa, Alejandro; Li, Bo; Chen, Jiakuan; Xu, Cheng-Yuan

    2016-01-01

    Phenotypic plasticity has been proposed as an important adaptive strategy for clonal plants in heterogeneous habitats. Increased phenotypic plasticity can be especially beneficial for invasive clonal plants, allowing them to colonize new environments even when genetic diversity is low. However, the relative importance of genetic diversity and phenotypic plasticity for invasion success remains largely unknown. Here, we performed molecular marker analyses and a common garden experiment to investigate the genetic diversity and phenotypic plasticity of the globally important weed Alternanthera philoxeroides in response to different water availability (terrestrial vs. aquatic habitats). This species relies predominantly on clonal propagation in introduced ranges. We therefore expected genetic diversity to be restricted in the two sampled introduced ranges (the USA and China) when compared to the native range (Argentina), but that phenotypic plasticity may allow the species' full niche range to nonetheless be exploited. We found clones from China had very low genetic diversity in terms of both marker diversity and quantitative variation when compared with those from the USA and Argentina, probably reflecting different introduction histories. In contrast, similar patterns of phenotypic plasticity were found for clones from all three regions. Furthermore, despite the different levels of genetic diversity, bioclimatic modeling suggested that the full potential bioclimatic distribution had been invaded in both China and USA. Phenotypic plasticity, not genetic diversity, was therefore critical in allowing A. philoxeroides to invade diverse habitats across broad geographic areas.

  16. The Relative Importance of Genetic Diversity and Phenotypic Plasticity in Determining Invasion Success of a Clonal Weed in the USA and China

    PubMed Central

    Geng, Yupeng; van Klinken, Rieks D.; Sosa, Alejandro; Li, Bo; Chen, Jiakuan; Xu, Cheng-Yuan

    2016-01-01

    Phenotypic plasticity has been proposed as an important adaptive strategy for clonal plants in heterogeneous habitats. Increased phenotypic plasticity can be especially beneficial for invasive clonal plants, allowing them to colonize new environments even when genetic diversity is low. However, the relative importance of genetic diversity and phenotypic plasticity for invasion success remains largely unknown. Here, we performed molecular marker analyses and a common garden experiment to investigate the genetic diversity and phenotypic plasticity of the globally important weed Alternanthera philoxeroides in response to different water availability (terrestrial vs. aquatic habitats). This species relies predominantly on clonal propagation in introduced ranges. We therefore expected genetic diversity to be restricted in the two sampled introduced ranges (the USA and China) when compared to the native range (Argentina), but that phenotypic plasticity may allow the species' full niche range to nonetheless be exploited. We found clones from China had very low genetic diversity in terms of both marker diversity and quantitative variation when compared with those from the USA and Argentina, probably reflecting different introduction histories. In contrast, similar patterns of phenotypic plasticity were found for clones from all three regions. Furthermore, despite the different levels of genetic diversity, bioclimatic modeling suggested that the full potential bioclimatic distribution had been invaded in both China and USA. Phenotypic plasticity, not genetic diversity, was therefore critical in allowing A. philoxeroides to invade diverse habitats across broad geographic areas. PMID:26941769

  17. The Relative Importance of Genetic Diversity and Phenotypic Plasticity in Determining Invasion Success of a Clonal Weed in the USA and China.

    PubMed

    Geng, Yupeng; van Klinken, Rieks D; Sosa, Alejandro; Li, Bo; Chen, Jiakuan; Xu, Cheng-Yuan

    2016-01-01

    Phenotypic plasticity has been proposed as an important adaptive strategy for clonal plants in heterogeneous habitats. Increased phenotypic plasticity can be especially beneficial for invasive clonal plants, allowing them to colonize new environments even when genetic diversity is low. However, the relative importance of genetic diversity and phenotypic plasticity for invasion success remains largely unknown. Here, we performed molecular marker analyses and a common garden experiment to investigate the genetic diversity and phenotypic plasticity of the globally important weed Alternanthera philoxeroides in response to different water availability (terrestrial vs. aquatic habitats). This species relies predominantly on clonal propagation in introduced ranges. We therefore expected genetic diversity to be restricted in the two sampled introduced ranges (the USA and China) when compared to the native range (Argentina), but that phenotypic plasticity may allow the species' full niche range to nonetheless be exploited. We found clones from China had very low genetic diversity in terms of both marker diversity and quantitative variation when compared with those from the USA and Argentina, probably reflecting different introduction histories. In contrast, similar patterns of phenotypic plasticity were found for clones from all three regions. Furthermore, despite the different levels of genetic diversity, bioclimatic modeling suggested that the full potential bioclimatic distribution had been invaded in both China and USA. Phenotypic plasticity, not genetic diversity, was therefore critical in allowing A. philoxeroides to invade diverse habitats across broad geographic areas. PMID:26941769

  18. The extent of hybridization and its impact on the genetic diversity and population structure of an invasive tree, Ulmus pumila (Ulmaceae)

    PubMed Central

    Zalapa, Juan E; Brunet, Johanne; Guries, Raymond P

    2010-01-01

    Ulmus pumila is considered an invasive tree in 41 of the United States. In this study, we examined the extent of hybridization in naturalized populations of U. pumila, its impact on genetic diversity and genetic structure and its potential role in explaining the invasion process of U. pumila. Genetic analyses indicated widespread hybridization with native Ulmus rubra in naturalized U. pumila populations. Hybridization increased the genetic diversity of U. pumila populations and affected their genetic structure. The level of genetic diversity in ‘mature’ accessions, many of which may represent original plantings throughout the USA, was high and similar to the diversity of East Asian accessions. Hybridization with the native red elm may play an important role in the success of Siberian elm as an invader in temperate regions of the USA. PMID:25567916

  19. European Invasion of North American Pinus strobus at Large and Fine Scales: High Genetic Diversity and Fine-Scale Genetic Clustering over Time in the Adventive Range

    PubMed Central

    Mandák, Bohumil; Hadincová, Věroslava; Mahelka, Václav; Wildová, Radka

    2013-01-01

    Background North American Pinus strobus is a highly invasive tree species in Central Europe. Using ten polymorphic microsatellite loci we compared various aspects of the large-scale genetic diversity of individuals from 30 sites in the native distribution range with those from 30 sites in the European adventive distribution range. To investigate the ascertained pattern of genetic diversity of this intercontinental comparison further, we surveyed fine-scale genetic diversity patterns and changes over time within four highly invasive populations in the adventive range. Results Our data show that at the large scale the genetic diversity found within the relatively small adventive range in Central Europe, surprisingly, equals the diversity found within the sampled area in the native range, which is about thirty times larger. Bayesian assignment grouped individuals into two genetic clusters separating North American native populations from the European, non-native populations, without any strong genetic structure shown over either range. In the case of the fine scale, our comparison of genetic diversity parameters among the localities and age classes yielded no evidence of genetic diversity increase over time. We found that SGS differed across age classes within the populations under study. Old trees in general completely lacked any SGS, which increased over time and reached its maximum in the sapling stage. Conclusions Based on (1) the absence of difference in genetic diversity between the native and adventive ranges, together with the lack of structure in the native range, and (2) the lack of any evidence of any temporal increase in genetic diversity at four highly invasive populations in the adventive range, we conclude that population amalgamation probably first happened in the native range, prior to introduction. In such case, there would have been no need for multiple introductions from previously isolated populations, but only several introductions from

  20. Non-invasive measurement of thyroid hormone in feces of a diverse array of avian and mammalian species.

    PubMed

    Wasser, Samuel K; Azkarate, Jurgi Cristòbal; Booth, Rebecca K; Hayward, Lisa; Hunt, Kathleen; Ayres, Katherine; Vynne, Carly; Gobush, Kathleen; Canales-Espinosa, Domingo; Rodríguez-Luna, Ernesto

    2010-08-01

    We developed and validated a non-invasive thyroid hormone measure in feces of a diverse array of birds and mammals. An I(131) radiolabel ingestion study in domestic dogs coupled with High Pressure Liquid Chromatography (HPLC) analysis, showed that peak excretion in feces occurred at 24-48h post-ingestion, with I(131)-labelled thyroid hormone metabolites excreted primarily as triiodothyronine (T3) and relatively little thyroxine (T4), at all excretion times examined. The immunoreactive T3 profile across these same HPLC fractions closely corresponded with the I(131) radioactive profile. By contrast, the T4 immunoreactive profile was disproportionately high, suggesting that T4 excretion included a high percentage of T4 stores. We optimized and validated T3 and T4 extraction and assay methods in feces of wild northern spotted owls, African elephants, howler monkeys, caribou, moose, wolf, maned wolf, killer whales and Steller sea lions. We explained 99% of the variance in high and low T3 concentrations derived from species-specific sample pools, after controlling for species and the various extraction methods tested. Fecal T3 reflected nutritional deficits in two male and three female howler monkeys held in captivity for translocation from a highly degraded habitat. Results suggest that thyroid hormone can be accurately and reliably measured in feces, providing important indices for environmental physiology across a diverse array of birds and mammals. PMID:20412809

  1. Magnetofection based on superparamagnetic iron oxide nanoparticle-mediated low lncRNA HOTAIR expression decreases the proliferation and invasion of glioma stem cells

    PubMed Central

    Fang, Kan; Liu, Peifeng; Dong, Suyan; Guo, Yanjie; Cui, Xinxin; Zhu, Xiaoying; Li, Xuan; Jiang, Lianghan; Liu, Te; Wu, Yuncheng

    2016-01-01

    Glioma stem cells (GSCs) are a special subpopulation of glioma cells that are key to the sensitivity of tumors to treatments and to the possibility of tumor recurrence. Identifying new strategies that inhibit the growth of GSCs are therefore important for developing novel therapies for glioblastoma multiforme (GBM). In this study, CD133+ human glioma stem cells were isolated and cultured. Magnetic nanoparticles were used to mediate the expression of siRNAs targeting the HOTAIR (si-HOTAIR) sequence in human gliomas. Effect of downregulation of HOTAIR expression on proliferation, invasion and in vivo tumorigenicity of human GSCs and underlying molecular mechanisms were further evaluated. The results of the MTT assay and flow cytometric analysis showed that downregulation of HOTAIR expression inhibited cell proliferation and induced cell cycle arrest. Transwell assays demonstrated that downregulation of HOTAIR expression resulted in a decrease in the invasive capability of GSCs. Moreover, magnetic nanoparticle-mediated low expression of HOTAIR effectively reduced the tumorigenic capacity of glioma stem cells in vivo. In addition, the results of qRT-PCR and western blot analysis demonstrated that downregulation of HOTAIR expression significantly increased the expression of PDCD4 in GSCs, in addition to reducing the expression of CCND1 and CDK4. An in-depth mechanistic analysis showed that downregulation of HOTAIR expression reduced the recruitment of downstream molecules, EZH2 and LSD1, thereby activating the expression of PDCD4 at the transcriptional level. In conclusion, downregulation of HOTAIR expression effectively promoted the expression of PDCD4, thereby inhibiting the proliferation, invasion and in vivo tumorigenicity of human GSCs. PMID:27277755

  2. Resting-state networks link invasive and noninvasive brain stimulation across diverse psychiatric and neurological diseases

    PubMed Central

    Fox, Michael D.; Buckner, Randy L.; Liu, Hesheng; Chakravarty, M. Mallar; Lozano, Andres M.; Pascual-Leone, Alvaro

    2014-01-01

    Brain stimulation, a therapy increasingly used for neurological and psychiatric disease, traditionally is divided into invasive approaches, such as deep brain stimulation (DBS), and noninvasive approaches, such as transcranial magnetic stimulation. The relationship between these approaches is unknown, therapeutic mechanisms remain unclear, and the ideal stimulation site for a given technique is often ambiguous, limiting optimization of the stimulation and its application in further disorders. In this article, we identify diseases treated with both types of stimulation, list the stimulation sites thought to be most effective in each disease, and test the hypothesis that these sites are different nodes within the same brain network as defined by resting-state functional-connectivity MRI. Sites where DBS was effective were functionally connected to sites where noninvasive brain stimulation was effective across diseases including depression, Parkinson's disease, obsessive-compulsive disorder, essential tremor, addiction, pain, minimally conscious states, and Alzheimer’s disease. A lack of functional connectivity identified sites where stimulation was ineffective, and the sign of the correlation related to whether excitatory or inhibitory noninvasive stimulation was found clinically effective. These results suggest that resting-state functional connectivity may be useful for translating therapy between stimulation modalities, optimizing treatment, and identifying new stimulation targets. More broadly, this work supports a network perspective toward understanding and treating neuropsychiatric disease, highlighting the therapeutic potential of targeted brain network modulation. PMID:25267639

  3. Distribution and Diversity of hmw1A Among Invasive Nontypeable Haemophilus influenzae Isolates in Iran

    PubMed Central

    Shahini Shams Abadi, Milad; Siadat, Seyed Davar; Vaziri, Farzam; Davari, Mehdi; Fateh, Abolfazl; Pourazar, Shahin; Abdolrahimi, Farid; Ghazanfari, Morteza

    2016-01-01

    Background: The pathogenesis of nontypeable Haemophilus influenzae (NTHi) begins with adhesion to the rhinopharyngeal mucosa. Almost 38–80% of NTHi clinical isolates produce proteins that belong to the High Molecular Weight (HMW) family of adhesins, which are believed to facilitate colonization. Methods: In the present study, the prevalence of hmwA, which encodes the HMW adhesin, was determined for a collection of 32 NTHi isolates. Restriction Fragment Length Polymorphism (RFLP) was performed to advance our understanding of hmwA binding sequence diversity. Results: The results demonstrated that hmwA was detected in 61% of NTHi isolates. According to RFLP, isolates were divided into three groups. Conclusion: Based on these observations, it is hypothesized that some strains of nontypeable Haemophilus influenzae infect some specific areas more than other parts. PMID:27141269

  4. Biological Warfare in Invasive Plants

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alliaria petiolata (garlic mustard) is an invasive species in temperate forests throughout North America that has led to a decrease in species diversity and alterations in nutrient cycling. Garlic mustard produces an arsenal of secondary chemicals in the glucosinolate family that have strong biocid...

  5. Genetic diversity in a morphologically conservative invasive taxon: Multiple introductions of swamp eels to the southeastern United States

    USGS Publications Warehouse

    Collins, T.M.; Trexler, J.C.; Nico, L.G.; Rawlings, T.A.

    2002-01-01

    Genetic analysis of introduced populations, especially in morphologically conservative taxa, can clarify introduction histories, identify management units and source populations, provide a more realistic estimate of the frequency of successful invasion, and suggest strategies for preventing further introductions. In the last 7 years, populations of swamp eels, referred to the Asian genus Monopterus (Family Synbranchidae) on the basis of external morphology, have been discovered in aquatic habitats near Atlanta, Georgia; Tampa, Florida; North Miami, Florida; and most recently in close proximity to Everglades National Park in Homestead, Florida. Swamp eels are large predators capable of dispersal over land and have the potential to disrupt already threatened ecosystems. We analyzed mitochondrial DNA sequences from four known populations in the continental United States and samples from Malaysia, Indonesia, Vietnam, and two locations in China to determine introduction histories, source populations, genetic diversity, and relationships among populations. Our results indicate that there have been at least three independent introductions of genetically distinct forms. Introduced populations in close proximity (separated by <40 km) are genetically distinct. The level of sequence difference among introduced populations reaches levels seen among sister families of teleost fishes for the same region of the mitochondrial genome. These genetically distinct introduced populations in all likelihood represent at least two and possibly three species. Regardless of species status, these genetically distinct lineages may be expected to vary in ecological or life-history traits, representing different potential threats to the ecosystems where they have been introduced. Given the success of swamp eels in invading many habitats around the world, further study of these eels is warranted to elucidate the characteristics of successful invaders and invasions.

  6. Loss of phytotelmata due to an invasive bromeliad-eating weevil and its potential effects on faunal diversity and biogeochemical cycles

    NASA Astrophysics Data System (ADS)

    Cooper, Teresa M.; Frank, J. Howard; Cave, Ronald D.

    2014-01-01

    Epiphytic tank bromeliads are important ecosystem engineers because they form phytotelmata that create habitat, increase species richness and abundance, create water sources and nutrient reservoirs in the canopy, and collect and redirect nutrients in forest ecosystems. Native bromeliad populations have been devastated in Florida (USA) because an invasive bromeliad-eating weevil (Metamasius callizona) has been destroying the plants. Tillandsia utriculata is a tank bromeliad that was once widespread from central to south Florida. Its populations have been hit hard by the weevil and are declining rapidly. This study quantifies the mortality rate caused by the weevil in a population of T. utriculata at the Enchanted Forest Sanctuary in central Florida and estimates the associated loss of phytotelmata. Estimations of phytotelmata were calculated for the T. utriculata baseline population, the population at 6 months into the study when 87% of the population was destroyed, and at the end of the study when less than 3% of the bromeliad population remained (99% of all deaths were caused by the weevil). The baseline population contained 16,758 L of water. At six months, there were 3180 L, and at the end of the study, there were 408 L. The loss of phytotelmata results in the loss of habitat, a decrease in biological diversity, and altered water and nutrient cycles and availability.

  7. Plasma miR-185 is decreased in patients with esophageal squamous cell carcinoma and might suppress tumor migration and invasion by targeting RAGE.

    PubMed

    Jing, Rongrong; Chen, Wen; Wang, Huimin; Ju, Shaoqing; Cong, Hui; Sun, Baolan; Jin, Qin; Chu, Shaopeng; Xu, Lili; Cui, Ming

    2015-11-01

    The receptor for advanced-glycation end products (RAGE) is upregulated in various cancers and has been associated with tumor progression, but little is known about its expression and regulation by microRNAs (miRNAs) in esophageal squamous cell carcinoma (ESCC). Here, we describe miR-185, which represses RAGE expression, and investigate the biological role of miR-185 in ESCC. In this study, we found that the high level of RAGE expression in 29 pairs of paraffin-embedded ESCC tissues was correlated positively with the depth of invasion by immunohistochemistry, suggesting that RAGE was involved in ESCC. We used bioinformatics searches and luciferase reporter assays to investigate the prediction that RAGE was regulated directly by miR-185. Besides, overexpression of miR-185 in ESCC cells was accompanied by 27% (TE-11) and 49% (Eca-109) reduced RAGE expression. The effect was further confirmed in RAGE protein by immunofluorescence in both cell lines. The effects were reversed following cotransfection with miR-185 and high-level expression of the RAGE vector. Furthermore, the biological role of miR-185 in ESCC cell lines was investigated using assays of cell viability, Ki-67 staining, and cell migration and invasion, as well as in a xenograft model. We found that overexpression of miR-185 inhibited migration and invasion by ESCC cells in vitro and reduced their capacity to develop distal pulmonary metastases in vivo partly through the RAGE/heat shock protein 27 pathway. Interestingly, in clinical specimens, the level of plasma miR-185 expression was decreased significantly (P = 0.002) in patients with ESCC [0.500; 95% confidence interval (CI) 0.248-1.676] compared with healthy controls (2.410; 95% CI 0.612-5.671). The value of the area under the receiver-operating characteristic curve was 0.73 (95% CI 0.604-0.855). In conclusion, our findings shed novel light on the role of miR-185/RAGE in ESCC metastasis, and plasma miR-185 has potential as a novel diagnostic biomarker

  8. Placenta-Enriched LincRNAs MIR503HG and LINC00629 Decrease Migration and Invasion Potential of JEG-3 Cell Line

    PubMed Central

    Muys, Bruna Rodrigues; Lorenzi, Júlio Cesar Cetrulo; Zanette, Dalila Luciola; Bueno, Rafaela de Barros Lima e; de Araújo, Luíza Ferreira; Dinarte-Santos, Anemari Ramos; Alves, Cleidson Pádua; Ramão, Anelisa; de Molfetta, Greice Andreotti; Vidal, Daniel Onofre; Silva, Wilson Araújo

    2016-01-01

    LINC00629 and MIR503HG are long intergenic non-coding RNAs (lincRNAs) mapped on chromosome X (Xq26), a region enriched for genes associated with human reproduction. Genes highly expressed in normal reproductive tissues and cancers (CT genes) are well known as potential tumor biomarkers. This study aimed to characterize the structure, expression, function and regulation mechanism of MIR503HG and LINC00629 lincRNAs. According to our data, MIR503HG expression was almost exclusive to placenta and LINC00629 was highly expressed in placenta and other reproductive tissues. Further analysis, using a cancer cell lines panel, showed that MIR503HG and LINC00629 were expressed in 50% and 100% of the cancer cell lines, respectively. MIR503HG was expressed predominantly in the nucleus of JEG-3 choriocarcinoma cells. We observed a positively correlated expression between MIR503HG and LINC00629, and between the lincRNAs and neighboring miRNAs. Also, both LINC00629 and MIR503GH could be negatively regulated by DNA methylation in an indirect way. Additionally, we identified new transcripts for MIR503HG and LINC00629 that are relatively conserved when compared to other primates. Furthermore, we found that overexpression of MIR503HG2 and the three-exon LINC00629 new isoforms decreased invasion and migration potential of JEG-3 tumor cell line. In conclusion, our results suggest that lincRNAs MIR503HG and LINC00629 impaired migration and invasion capacities in a choriocarcinoma in vitro model, indicating a potential role in human reproduction and tumorigenesis. Moreover, the MIR503HG expression pattern found here could indicate a putative new tumor biomarker. PMID:27023770

  9. Invasive and Noninvasive Streptococcus pneumoniae Capsule and Surface Protein Diversity following the Use of a Conjugate Vaccine

    PubMed Central

    Croney, Christina M.; Nahm, Moon H.; Juhn, Steven K.; Briles, David E.

    2013-01-01

    The 13-valent pneumococcal conjugate vaccine (PCV13) was introduced in the United States in 2010 for the prevention of invasive pneumococcal disease (IPD) and otitis media. While many studies have reported its potential efficacy for IPD, not much is known about the epidemiology of noninvasive disease following its introduction. We characterized the capsular types and surface protein genes of noninvasive pediatric pneumococcal isolates collected between 2002 and 2010 (n = 1,058) at Children's of Alabama following the introduction of PCV7 and tested a subset of noninvasive and previously characterized IPD isolates for the presence of the pspA, pspC, and rrgC genes, which encode protection-eliciting proteins. PCV7 serotypes had dramatically decreased by 2010 (P < 0.0001), and only 50% of all noninvasive infections were caused by the PCV13 capsular serotypes. Serotype 19A accounted for 32% of the noninvasive isolates, followed by serotypes 35B (9%), 19F (7%), and 6C (6%). After 7 years of PCV7 usage, there were no changes in the frequencies of the pspA or pspC genes; 96% of the strains were positive for family 1 or 2 pspA genes, and 81% were also positive for pspC. Unexpectedly, more noninvasive than invasive strains were positive for rrgC (P < 0.0001), and the proportion of rrgC-positive strains in 2008 to 2010 was greater than that in 2002 to 2008 (IPD, P < 0.02; noninvasive, P < 0.001). Serotypes 19F, 19A, and 35B were more frequently rrgC positive (P < 0.005) than other serotypes. A vaccine containing antigens, such as PspA, PspC, and/or RrgC, can provide coverage against most non-PCV13-type pneumococci. Continued surveillance is critical for optimal future vaccine development. PMID:24006139

  10. Decreased expression of let-7c is associated with non-response of muscle-invasive bladder cancer patients to neoadjuvant chemotherapy.

    PubMed

    Vinall, Ruth L; Tepper, Clifford G; Ripoll, Alexandra A Z; Gandour-Edwards, Regina F; Durbin-Johnson, Blythe P; Yap, Stanley A; Ghosh, Paramita M; deVere White, Ralph W

    2016-03-01

    The identification and development of biomarkers which predict response of muscle invasive bladder cancer (MIBC) patients to neoadjuvant chemotherapy would likely increase usage of this treatment option and thereby improve patient survival rates. MiRNA array and qRT-PCR validation was used to identify miRNA which are associated with response to neoadjuvant chemotherapy. RNA was extracted from a total of 41 archival, fully annotated, MIBC patient diagnostic biopsies (20 chemo-responders and 21 non-responders (response is defined as > 5 year survival rate and being pT0 post-chemotherapy)). Microarray and qPCR identified let-7c as being differentially expressed in chemo-responder versus non-responder patients. Patients with higher let-7c expression levels had significantly higher odds of responding to chemotherapy (p = 0.023, OR 2.493, 95% CI 1.121, 5.546), and assessment of let-7c levels allowed for prediction of patient response (AUC 0.72, positive predictive value 59%). Decreased let-7c was associated with MIBC incidence (p < 0.001), and significantly correlated with other related miRNA including those that were not differentially expressed between responders and non-responders. The combined data indicate let-7c plays a role in mediating chemoresistance to neoadjuvant chemotherapy in MIBC patients, and is a modest, yet clinically meaningful, predictor of patient response. PMID:27382433

  11. Decreased Diversity but Increased Substitution Rate in Host mtDNA as a Consequence of Wolbachia Endosymbiont Infection

    PubMed Central

    Shoemaker, D. DeWayne; Dyer, Kelly A.; Ahrens, Mike; McAbee, Kevin; Jaenike, John

    2004-01-01

    A substantial fraction of insects and other terrestrial arthropods are infected with parasitic, maternally transmitted endosymbiotic bacteria that manipulate host reproduction. In addition to imposing direct selection on the host to resist these effects, endosymbionts may also have indirect effects on the evolution of the mtDNA with which they are cotransmitted. Patterns of mtDNA diversity and evolution were examined in Drosophila recens, which is infected with the endosymbiont Wolbachia, and its uninfected sister species D. subquinaria. The level of mitochondrial, but not nuclear, DNA diversity is much lower in D. recens than in D. subquinaria, consistent with the hypothesized diversity-purging effects of an evolutionarily recent Wolbachia sweep. The dN/dS ratio in mtDNA is significantly greater in D. recens, suggesting that Muller's ratchet has brought about an increased rate of substitution of slightly deleterious mutations. The data also reveal elevated rates of synonymous substitutions in D. recens, suggesting that these sites may experience weak selection. These findings show that maternally transmitted endosymbionts can severely depress levels of mtDNA diversity within an infected host species, while accelerating the rate of divergence among mtDNA lineages in different species. PMID:15611174

  12. Population genetics of a marine bivalve, Pinctada maxima, throughout the Indo-Australian Archipelago shows differentiation and decreased diversity at range limits.

    PubMed

    Lind, Curtis E; Evans, Brad S; Taylor, Joseph J U; Jerry, Dean R

    2007-12-01

    Intraspecific genetic diversity governs the potential of species to prevail in the face of environmental or ecological challenges; therefore, its protection is critical. The Indo-Australian Archipelago (IAA) is a significant reservoir of the world's marine biodiversity and a region of high conservation priority. Yet, despite indications that the IAA may harbour greater intraspecific variation, multiple-locus genetic diversity data are limited. We investigated microsatellite DNA variation in Pinctada maxima populations from the IAA to elucidate potential factors influencing levels of genetic diversity in the region. Results indicate that genetic diversity decreases as the geographical distance away from central Indonesia increases, and that populations located towards the centre of P. maxima's range are more genetically diverse than those located peripherally (P < 0.01). Significant partitioning of genetic variation was identified (F(ST) = 0.027; R(ST) = 0.023, P < 0.001) and indicates that historical biogeographical episodes or oceanographic factors have shaped present population genetic structure. We propose that the genetic diversity peak in P. maxima populations may be due to (i) an abundance of suitable habitat within the IAA, meaning larger, more temporally stable populations can be maintained and are less likely to encounter genetic bottlenecks; and/or (ii) the close proximity of biogeographical barriers around central Indonesia results in increased genetic diversity in the region because of admixture of genetically divergent populations. We encourage further genetic diversity studies of IAA marine biota to confirm whether this region has a significant role in maintaining intraspecific diversity, which will greatly assist the planning and efficacy of future conservation efforts.

  13. Yeast diversity associated with invasive Dendroctonus valens killing Pinus tabuliformis in China using culturing and molecular methods.

    PubMed

    Lou, Qiao-Zhe; Lu, Min; Sun, Jiang-Hua

    2014-08-01

    Bark beetle-associated yeasts are much less studied than filamentous fungi, yet they are also considered to play important roles in beetle nutrition, detoxification, and chemical communication. The red turpentine beetle, Dendroctonus valens, an invasive bark beetle introduced from North America, became one of the most destructive pests in China, having killed more than 10 million Pinus tabuliformis as well as other pine species. No investigation of yeasts associated with this bark beetle in its invaded ranges has been conducted so far. The aim of this study was to assess the diversity of yeast communities in different microhabitats and during different developmental stages of Den. valens in China using culturing and denaturing gradient gel electrophoresis (DGGE) approaches and to compare the yeast flora between China and the USA. The yeast identity was confirmed by sequencing the D1/D2 domain of LSU ribosomal DNA (rDNA). In total, 21 species (13 ascomycetes and eight basidiomycetes) were detected by culturing method, and 12 species (11 ascomycetes and one basidiomycetes) were detected by molecular methods from China. The most frequent five species in China were Candida piceae (Ogataea clade), Cyberlindnera americana, Candida oregonensis (Metschnikowia clade), Candida nitratophila (Ogataea clade) and an undescribed Saccharomycopsis sp., detected by both methods. Seven species were exclusively detected by DGGE. Ca. oregonensis (Metschnikowia clade) was the most frequently detected species by DGGE method. Eight species (all were ascomycetes) from the USA were isolated; seven of those were also found in China. We found significant differences in yeast total abundance as well as community composition between different developmental stages and significant differences between the surface and the gut. The frass yeast community was more similar to that of Den. valens surface or larvae than to the community of the gut or adults. Possible functions of the yeast associates are

  14. Mitochondrial DNA revealed the extent of genetic diversity and invasion origin of populations from two separate invaded areas of a newly invasive pest, Cydia pomonella (L.) (Lepidoptera: Tortricidae) in China.

    PubMed

    Li, Y; Duan, X; Qiao, X; Li, X; Wang, K; Men, Q; Chen, M

    2015-08-01

    Cydia pomonella is a serious invasive insect pest in China, and has caused severe damage to the production of apple and pear in its invaded areas. This species is distributing in the northwest and northeast of China, but no occurrence of it has been recorded in the large areas (about 3000-5000 km away) between the invaded northwestern and northeastern regions despite continuous monitoring. As yet the genetic diversity and invasion origin of the C. pomonella populations in Northwestern and Northeastern China is obscure. In this study, we investigate the genetic diversity of 14 populations of C. pomonella sampled throughout the main distribution regions in Northwestern (Xinjiang and Gansu Provinces) and Northeastern (Heilongjiang Province) China and compared them with nine populations from Europe and other continents using the mitochondrial COI, COII and Cytb genes. Both the populations from Northeastern and Northwestern China shared some haplotypes with populations from other countries. Haplotypes of the three mitochondrial genes had a different distribution in Northeastern and Northwestern China. The northeastern populations had more private haplotypes than the northwestern populations. A large number of the individuals from northwestern populations shared a few haplotypes of each of the three genes. The haplotype numbers and haplotype diversities of the northeastern populations were similar to those of field populations in other countries, but were higher than those of the northwestern populations. Populations from the Northwestern China showed similar haplotype number and haplotype diversity. We conclude that the population genetic background of C. pomonella populations in Northeastern and Northwestern China varies due to different invasion sources and that this should be considered before the application of new pest control tactics.

  15. Mitochondrial DNA revealed the extent of genetic diversity and invasion origin of populations from two separate invaded areas of a newly invasive pest, Cydia pomonella (L.) (Lepidoptera: Tortricidae) in China.

    PubMed

    Li, Y; Duan, X; Qiao, X; Li, X; Wang, K; Men, Q; Chen, M

    2015-08-01

    Cydia pomonella is a serious invasive insect pest in China, and has caused severe damage to the production of apple and pear in its invaded areas. This species is distributing in the northwest and northeast of China, but no occurrence of it has been recorded in the large areas (about 3000-5000 km away) between the invaded northwestern and northeastern regions despite continuous monitoring. As yet the genetic diversity and invasion origin of the C. pomonella populations in Northwestern and Northeastern China is obscure. In this study, we investigate the genetic diversity of 14 populations of C. pomonella sampled throughout the main distribution regions in Northwestern (Xinjiang and Gansu Provinces) and Northeastern (Heilongjiang Province) China and compared them with nine populations from Europe and other continents using the mitochondrial COI, COII and Cytb genes. Both the populations from Northeastern and Northwestern China shared some haplotypes with populations from other countries. Haplotypes of the three mitochondrial genes had a different distribution in Northeastern and Northwestern China. The northeastern populations had more private haplotypes than the northwestern populations. A large number of the individuals from northwestern populations shared a few haplotypes of each of the three genes. The haplotype numbers and haplotype diversities of the northeastern populations were similar to those of field populations in other countries, but were higher than those of the northwestern populations. Populations from the Northwestern China showed similar haplotype number and haplotype diversity. We conclude that the population genetic background of C. pomonella populations in Northeastern and Northwestern China varies due to different invasion sources and that this should be considered before the application of new pest control tactics. PMID:25895900

  16. Microsatellites reveal origin and genetic diversity of Eurasian invasions by one of the world's most notorious marine invader, Mnemiopsis leidyi (Ctenophora).

    PubMed

    Reusch, Thorsten B H; Bolte, Sören; Sparwel, Maximiliane; Moss, Anthony G; Javidpour, Jamileh

    2010-07-01

    Marine invasions are taking place at an increasing rate. When occurring in blooms, zooplanktivorous comb jellies of the genus Mnemiopsis are able to cause pelagic regime shifts in coastal areas and may cause the collapse of commercially important fish populations. Using microsatellites, developed for the first time in the phylum Ctenophora, we show that Mnemiopsis leidyi has colonized Eurasia from two source regions. Our preliminary data set included four sites within the putative source region (US East Coast and Gulf of Mexico) and 10 invaded locations in Eurasian waters. Bayesian clustering and phylogeographic approaches revealed the origin of earlier invasions of the Black and Caspian Sea in the 1980s/1990s within or close to the Gulf of Mexico, while the 2006 invasion of the North and Baltic Seas can be directly traced to New England (pairwise F(ST) = 0). We found no evidence for mixing among both gene pools in the invaded areas. While the genetic diversity (allelic richness) remained similar in the Baltic Sea compared to the source region New England, it was reduced in the North Sea, supporting the view of an initial invasion of Northern Europe to a Baltic Sea port. In Black and Caspian Sea samples, we found a gradual decline in allelic richness compared to the Gulf of Mexico region, supporting a stepping-stone model of colonization with two sequential genetic founder events. Our data also suggest that current practices of ballast water treatment are insufficient to prevent repeated invasions of gelatinous zooplankton.

  17. Evolution and genetic diversity of the Spain23F-ST81 clone causing adult invasive pneumococcal disease in Barcelona (1990–2012)

    PubMed Central

    Domenech, A.; Ardanuy, C.; Grau, I.; Calatayud, L.; Pallares, R.; Fenoll, A.; Brueggemann, A. B.; Liñares, J.

    2014-01-01

    Objectives We aimed to analyse the clinical epidemiology and genetic diversity of invasive pneumococcal disease (IPD) episodes attributed to the Spain23F-ST81 (PMEN1) clone. Methods Fifty-eight (2.7%) of 2117 invasive pneumococci isolated from adult patients during the 1990–2012 period shared a PFGE pattern related to the PMEN1 clone. The genotype was confirmed by multilocus sequence typing. The pbp2x, pbp1a, pbp2b and pspA genes were PCR-amplified and sequenced. Polymorphisms in the pspC gene were identified by PCR restriction fragment length polymorphism. The presence of transposons with erythromycin and tetracycline resistance determinants was detected by PCR. Results The prevalence of the PMEN1 clone increased from 0.8% in 1991 to 6.2% in 2001, and decreased to 0% in 2010–12, concomitant with the introduction of the seven-valent pneumococcal conjugate vaccine for children. A total of 93.1% of patients had pneumonia, meningitis or peritonitis; 87.9% of patients had associated underlying diseases, mainly cancer, chronic obstructive pulmonary disease and diabetes. Two closely related sequence types (STs) (ST81, n = 52; ST85, n = 6) were detected, with different serotypes: 23F (n = 42), 19A (n = 9) and 19F (n = 6). All the isolates were resistant to penicillin, co-trimoxazole and chloramphenicol. All the isolates also shared the same pbp1a allele, whereas multiple alleles of pbp2b, pbp2x, pspA and pspC were detected. Of the isolates, 89.7% were tetracycline resistant and 60.3% (n = 35) were macrolide resistant, and resistance was associated with different Tn916-like transposons. Conclusions Adult IPD caused by this clone was mainly detected in patients with underlying conditions, and genetic variability was observed among PMEN1 isolates collected in our area over the past 20 years. PMID:24324223

  18. Chloramphenicol and tetracycline decrease motility and increase invasion and attachment gene expression in specific isolates of multidrug-resistant Salmonella enterica serovar Typhimurium

    PubMed Central

    Brunelle, Brian W.; Bearson, Bradley L.; Bearson, Shawn M. D.

    2015-01-01

    Salmonella enterica serovar Typhimurium is one of the most common serovars isolated from humans and livestock, and over 35% of these isolates are resistant to three or more antibiotics. Multidrug-resistant (MDR) Salmonella is a public health concern as it is associated with increased morbidity in patients compared to antibiotic sensitive strains, though it is unknown how the antibiotic resistant isolates lead to a more severe infection. Cellular invasion is temporally regulated in Salmonella and normally occurs during late-log and stationary growth. However, our previous work determined that a 30 min exposure to a sub-inhibitory concentration of tetracycline can induce the full invasion phenotype during early-log growth in certain MDR S. Typhimurium isolates. The current study examined whether sub-inhibitory concentrations of other antibiotics could also induce the invasiveness in the same set of isolates. Ampicillin and streptomycin had no effect on invasion, but certain concentrations of chloramphenicol were found to induce invasion in a subset of isolates. Two of the isolates induced by chloramphenicol were also inducible by tetracycline. RNA-seq analyses demonstrated that chloramphenicol and tetracycline both down-regulated motility gene expression, while up-regulating genes associated with attachment, invasion, and intracellular survival. Eleven fimbrial operons were up-regulated, which is notable as only three fimbrial operons were thought to be inducible in culture; six of these up-regulated operons have been reported to play a role in Salmonella persistence in mice. Overall, these data show that the normal progression of the genetic pathways that regulate invasion can be expedited to occur within 30 min due to antibiotic exposure. This altered invasion process due to antibiotics may play a role in the increased intensity and duration of infection observed in patients with MDR Salmonella. PMID:25688233

  19. Exploring origins, invasion history and genetic diversity of Imperata cylindrica (L.) P. Beauv. (Cogongrass) in the United States using genotyping by sequencing.

    PubMed

    Burrell, A Millie; Pepper, Alan E; Hodnett, George; Goolsby, John A; Overholt, William A; Racelis, Alexis E; Diaz, Rodrigo; Klein, Patricia E

    2015-05-01

    Imperata cylindrica (Cogongrass, Speargrass) is a diploid C4 grass that is a noxious weed in 73 countries and constitutes a significant threat to global biodiversity and sustainable agriculture. We used a cost-effective genotyping-by-sequencing (GBS) approach to identify the reproductive system, genetic diversity and geographic origins of invasions in the south-eastern United States. In this work, we demonstrated the advantage of employing the closely related, fully sequenced crop species Sorghum bicolor (L.) Moench as a proxy reference genome to identify a set of 2320 informative single nucleotide and insertion-deletion polymorphisms. Genetic analyses identified four clonal lineages of cogongrass and one clonal lineage of Imperata brasiliensis Trin. in the United States. Each lineage was highly homogeneous, and we found no evidence of hybridization among the different lineages, despite geographical overlap. We found evidence that at least three of these lineages showed clonal reproduction prior to introduction to the United States. These results indicate that cogongrass has limited evolutionary potential to adapt to novel environments and further suggest that upon arrival to its invaded range, this species did not require local adaptation through hybridization/introgression or selection of favourable alleles from a broad genetic base. Thus, cogongrass presents a clear case of broad invasive success, across a diversity of environments, in a clonal organism with limited genetic diversity. PMID:25864837

  20. Prolactin decrease and shift to a normal-like isoform profile during treatment with quinagolide in a patient affected by an invasive prolactinoma.

    PubMed

    Guido, R; Valenti, S; Foppiani, L; De Martini, D; Cossu, M; Giusti, M

    1997-05-01

    Prolactin (PRL) circulates as multiple molecular weight variants: glycosylated phosphorylated, deamidated and sulphated forms. The profiles of the forms, as determined by isoelectrofocusing (IEF), differ in physiological and pathological conditions. The case of a 72-year-old woman affected by an invasive prolactinoma is described. The patient had undergone surgical treatment followed by radiotherapy at the age of 71 years. Bromocriptine therapy followed (up to 10 mg/die), but the PRL levels were still extremely high (over 13,000 micrograms/l as determined by IRMA, after dilution). We therefore treated the patient with quinagolide, at increasing dosages, from 150 micrograms/die on day 0 to 600 micrograms/die on day 220. This treatment progressively lowered PRL to 23.2 micrograms/l. In addition to a decrease in PRL levels, a progressive change in the IEF profile was also noted. Indeed, on day 0, the PRL isoforms were very acidic and during treatment they progressively shifted toward a more basic range. For purpose of comparison PRL profiles were also determined in 8 women with pathological hyperprolactinaemia (group A, aged 16-50 years, PRL levels: 25.1-170.4 micrograms/l), in 6 normal women (group B, aged 25-29 years, PRL levels: 3.4-7.9 micrograms/l) and in 5 normal women during a TRH test (group C, aged 17-52 years, PRL levels: 2.7-10.3 micrograms/l). The profiles observed in group A had a single major peak at isoelectric point (pI) 6.5, while the group B and C profiles were more heterogeneous displaying multiple minor peaks, the majority of the molecules being in a more basic range (pI 6.9 for group B and pI 7.5 for group C). During treatment, the profiles of our subject at first resembled those of group A; subsequently, when the PRL levels had normalised, the profile resembled those noted in group B. Altered (immature?, more glycosilated?, less bioactive?) PRL molecules could be secreted by the tumour. These data show that quinagolide successfully reduced PRL

  1. Chronic Trichuris muris Infection Decreases Diversity of the Intestinal Microbiota and Concomitantly Increases the Abundance of Lactobacilli.

    PubMed

    Holm, Jacob Bak; Sorobetea, Daniel; Kiilerich, Pia; Ramayo-Caldas, Yuliaxis; Estellé, Jordi; Ma, Tao; Madsen, Lise; Kristiansen, Karsten; Svensson-Frej, Marcus

    2015-01-01

    The intestinal microbiota is vital for shaping the local intestinal environment as well as host immunity and metabolism. At the same time, epidemiological and experimental evidence suggest an important role for parasitic worm infections in maintaining the inflammatory and regulatory balance of the immune system. In line with this, the prevalence of persistent worm infections is inversely correlated with the incidence of immune-associated diseases, prompting the use of controlled parasite infections for therapeutic purposes. Despite this, the impact of parasite infection on the intestinal microbiota, as well as potential downstream effects on the immune system, remain largely unknown. We have assessed the influence of chronic infection with the large-intestinal nematode Trichuris muris, a close relative of the human pathogen Trichuris trichiura, on the composition of the murine intestinal microbiota by 16S ribosomal-RNA gene-based sequencing. Our results demonstrate that persistent T. muris infection dramatically affects the large-intestinal microbiota, most notably with a drop in the diversity of bacterial communities, as well as a marked increase in the relative abundance of the Lactobacillus genus. In parallel, chronic T. muris infection resulted in a significant shift in the balance between regulatory and inflammatory T cells in the intestinal adaptive immune system, in favour of inflammatory cells. Together, these data demonstrate that chronic parasite infection strongly influences the intestinal microbiota and the adaptive immune system. Our results illustrate the complex interactions between these factors in the intestinal tract, and contribute to furthering the understanding of this interplay, which is of crucial importance considering that 500 million people globally are suffering from these infections and their potential use for therapeutic purposes. PMID:25942314

  2. Chronic Trichuris muris Infection Decreases Diversity of the Intestinal Microbiota and Concomitantly Increases the Abundance of Lactobacilli.

    PubMed

    Holm, Jacob Bak; Sorobetea, Daniel; Kiilerich, Pia; Ramayo-Caldas, Yuliaxis; Estellé, Jordi; Ma, Tao; Madsen, Lise; Kristiansen, Karsten; Svensson-Frej, Marcus

    2015-01-01

    The intestinal microbiota is vital for shaping the local intestinal environment as well as host immunity and metabolism. At the same time, epidemiological and experimental evidence suggest an important role for parasitic worm infections in maintaining the inflammatory and regulatory balance of the immune system. In line with this, the prevalence of persistent worm infections is inversely correlated with the incidence of immune-associated diseases, prompting the use of controlled parasite infections for therapeutic purposes. Despite this, the impact of parasite infection on the intestinal microbiota, as well as potential downstream effects on the immune system, remain largely unknown. We have assessed the influence of chronic infection with the large-intestinal nematode Trichuris muris, a close relative of the human pathogen Trichuris trichiura, on the composition of the murine intestinal microbiota by 16S ribosomal-RNA gene-based sequencing. Our results demonstrate that persistent T. muris infection dramatically affects the large-intestinal microbiota, most notably with a drop in the diversity of bacterial communities, as well as a marked increase in the relative abundance of the Lactobacillus genus. In parallel, chronic T. muris infection resulted in a significant shift in the balance between regulatory and inflammatory T cells in the intestinal adaptive immune system, in favour of inflammatory cells. Together, these data demonstrate that chronic parasite infection strongly influences the intestinal microbiota and the adaptive immune system. Our results illustrate the complex interactions between these factors in the intestinal tract, and contribute to furthering the understanding of this interplay, which is of crucial importance considering that 500 million people globally are suffering from these infections and their potential use for therapeutic purposes.

  3. Efficacy of a sensory deterrent and pipe modifications in decreasing entrainment of juvenile green sturgeon (Acipenser medirostris) at unscreened water diversions

    PubMed Central

    Poletto, Jamilynn B.; Cocherell, Dennis E.; Mussen, Timothy D.; Ercan, Ali; Bandeh, Hossein; Levent Kavvas, M.; Cech, Joseph J.; Fangue, Nann A.

    2014-01-01

    Water projects designed to extract fresh water for local urban, industrial and agricultural use throughout rivers and estuaries worldwide have contributed to the fragmentation and degradation of suitable habitat for native fishes. The number of water diversions located throughout the Sacramento–San Joaquin watershed in California's Central Valley exceeds 3300, and the majority of these are unscreened. Many anadromous fish species are susceptible to entrainment into these diversions, potentially impacting population numbers. In the laboratory, juvenile green sturgeon (Acipenser medirostris) have been shown to have high entrainment rates into unscreened diversions compared with those of other native California fish species, which may act as a significant source of mortality for this already-threatened species. Therefore, we tested the efficacy of a sensory deterrent (strobe light) and two structural pipe modifications (terminal pipe plate and upturned pipe configuration) in decreasing the entrainment of juvenile green sturgeon (mean mass ± SEM = 162.9 ± 4.0 g; mean fork length = 39.4 ± 0.3 cm) in a large (>500 kl) outdoor flume fitted with a water-diversion pipe 0.46 m in diameter. While the presence of the strobe light did not affect fish entrainment rates, the terminal pipe plate and upturned pipe modifications significantly decreased the proportion of fish entrained out of the total number tested relative to control conditions (0.13 ± 0.02 and 0.03 ± 0.02 vs. 0.44 ± 0.04, respectively). These data suggest that sensory deterrents using visual stimuli are not an effective means to reduce diversion pipe interactions for green sturgeon, but that structural alterations to diversions can successfully reduce entrainment for this species. Our results are informative for the development of effective management strategies to mitigate the impacts of water diversions on sturgeon populations and suggest that effective restoration

  4. Extreme differences in population structure and genetic diversity for three invasive congeners: knotweeds in western North America

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Japanese, giant, and the hybrid Bohemian knotweeds (Fallopia japonica, F. sachalinensis and F. x bohemica) have invaded the western USA and Canada, as well as other regions of the world. The distribution of these species in western North America, and their mode of invasion, is relatively unresolved....

  5. Human Mesenchymal Stem Cells of Diverse Origins Support Persistent Infection with Kaposi’s Sarcoma-Associated Herpesvirus and Manifest Distinct Angiogenic, Invasive, and Transforming Phenotypes

    PubMed Central

    Lee, Myung-Shin; Yuan, Hongfeng; Jeon, Hyungtaek; Zhu, Ying; Yoo, Seungmin; Shi, Songtao; Krueger, Brian; Renne, Rolf; Lu, Chun; Jung, Jae U.

    2016-01-01

    ABSTRACT Kaposi’s sarcoma (KS), a highly angiogenic and invasive tumor often involving different organ sites, including the oral cavity, is caused by infection with Kaposi’s sarcoma-associated herpesvirus (KSHV). Diverse cell markers have been identified on KS tumor cells, but their origin remains an enigma. We previously showed that KSHV could efficiently infect, transform, and reprogram rat primary mesenchymal stem cells (MSCs) into KS-like tumor cells. In this study, we showed that human primary MSCs derived from diverse organs, including bone marrow (MSCbm), adipose tissue (MSCa), dental pulp, gingiva tissue (GMSC), and exfoliated deciduous teeth, were permissive to KSHV infection. We successfully established long-term cultures of KSHV-infected MSCa, MSCbm, and GMSC (LTC-KMSCs). While LTC-KMSCs had lower proliferation rates than the uninfected cells, they expressed mixtures of KS markers and displayed differential angiogenic, invasive, and transforming phenotypes. Genetic analysis identified KSHV-derived microRNAs that mediated KSHV-induced angiogenic activity by activating the AKT pathway. These results indicated that human MSCs could be the KSHV target cells in vivo and established valid models for delineating the mechanism of KSHV infection, replication, and malignant transformation in biologically relevant cell types. PMID:26814175

  6. Elucidating the native sources of an invasive tree species, Acacia pycnantha, reveals unexpected native range diversity and structure

    PubMed Central

    Ndlovu, Joice; Richardson, David M.; Wilson, John R. U.; O'Leary, Martin; Le Roux, Johannes J.

    2013-01-01

    Background and Aims Understanding the introduction history of invasive plant species is important for their management and identifying effective host-specific biological control agents. However, uncertain taxonomy, intra- and interspecific hybridization, and cryptic speciation may obscure introduction histories, making it difficult to identify native regions to explore for host-specific agents. The overall aim of this study was to identify the native source populations of Acacia pycnantha, a tree native to south-eastern Australia and invasive in South Africa, Western Australia and Portugal. Using a phylogeographical approach also allowed an exploration of the historical processes that have shaped the genetic structure of A. pycnantha in its native range. Methods Nuclear (nDNA) and plastid DNA sequence data were used in network and tree-building analyses to reconstruct phylogeographical relationships between native and invasive A. pycnantha populations. In addition, mismatch distributions, relative rates and Bayesian analyses were used to infer recent demographic processes and timing of events in Australia that led to population structure and diversification. Key Results The plastid network indicated that Australian populations of A. pycnantha are geographically structured into two informally recognized lineages, the wetland and dryland forms, whereas the nuclear phylogeny showed little geographical structure between these two forms. Moreover, the dryland form of A. pycnantha showed close genetic similarity to the wetland form based on nDNA sequence data. Hybrid zones may explain these findings, supported here by incongruent phylogenetic placement of some of these taxa between nuclear and plastid genealogies. Conclusions It is hypothesized that habitat fragmentation due to cycles of aridity inter-dispersed with periods of abundant rainfall during the Pleistocene (approx. 100 kya) probably gave rise to native dryland and wetland forms of A. pycnantha. Although the

  7. Integrated assessment of biological invasions.

    PubMed

    Ibáñez, Ines; Diez, Jeffrey M; Miller, Luke P; Olden, Julian D; Sorte, Cascade J B; Blumenthal, Dana M; Bradley, Bethany A; D'Antonio, Carla M; Dukes, Jeffrey S; Early, Regan I; Grosholz, Edwin D; Lawler, Joshua J

    2014-01-01

    As the main witnesses of the ecological and economic impacts of invasions on ecosystems around the world, ecologists seek to provide the relevant science that informs managers about the potential for invasion of specific organisms in their region(s) of interest. Yet, the assorted literature that could inform such forecasts is rarely integrated to do so, and further, the diverse nature of the data available complicates synthesis and quantitative prediction. Here we present a set of analytical tools for synthesizing different levels of distributional and/or demographic data to produce meaningful assessments of invasion potential that can guide management at multiple phases of ongoing invasions, from dispersal to colonization to proliferation. We illustrate the utility of data-synthesis and data-model assimilation approaches with case studies of three well-known invasive species--a vine, a marine mussel, and a freshwater crayfish--under current and projected future climatic conditions. Results from the integrated assessments reflect the complexity of the invasion process and show that the most relevant climatic variables can have contrasting effects or operate at different intensities across habitat types. As a consequence, for two of the study species climate trends will increase the likelihood of invasion in some habitats and decrease it in others. Our results identified and quantified both bottlenecks and windows of opportunity for invasion, mainly related to the role of human uses of the landscape or to disruption of the flow of resources. The approach we describe has a high potential to enhance model realism, explanatory insight, and predictive capability, generating information that can inform management decisions and optimize phase-specific prevention and control efforts for a wide range of biological invasions.

  8. RNAi-mediated Downregulation of Urokinase Plasminogen Activator Receptor (uPAR) and Matrix Metalloprotease-9 (MMP-9) in Human Breast Cancer Cells Results in Decreased Tumor Invasion, Angiogenesis and Growth

    PubMed Central

    Kunigal, Sateesh; Lakka, Sajani S.; Gondi, Christopher S.; Estes, Norman; Rao, Jasti S.

    2007-01-01

    The serine protease urokinase-type plasminogen activator (uPA) plays a significant role in tumor cell invasion and metastasis when bound to its specific receptor, uPAR (also known as CD87). In addition to the uPA-uPAR system, matrix metalloproteinases (MMPs) are involved in tumor cell invasion and metastasis. In this study, we achieved specific inhibition of uPAR and MMP-9 using RNAi technology. We introduced small interfering RNA (siRNA) to downregulate the expression of uPAR and MMP-9 (pUM) in breast cancer cell lines (MDA MB 231 and ZR 75 1). In vitro angiogenesis studies indicated a decrease in the angiogenic potential of the treated cells; in particular, a remarkable decrease was observed in the cells treated with bicistronic construct (pUM) in comparision to the controls. Additionally, bicistronic construct inhibited the formation of capillary-like structures in in vivo models of angiogenesis. Similarly, the invasive potential and migration decreased dramatically when treated with the bicistronic construct as shown by matrigel invasion and migration assays. These results suggest a synergistic effect from the simultaneous downregulation of uPAR and MMP-9. We also assessed the levels of phosphorylated forms of MAPK, ERK, and AKT signaling pathway molecules and found reduction in the levels of these molecules in cells treated with the bicistronic construct as compared to the control cells. Furthermore, targeting both uPAR and MMP-9 totally regressed orthotopic breast tumors in nude mice. In conclusion, our results provide evidence that the simultaneous downregulation of uPAR and MMP-9 using RNAi technology may provide an effective tool for breast cancer therapy. PMID:17657740

  9. Decreased expression of long non-coding RNA GAS5 indicates a poor prognosis and promotes cell proliferation and invasion in hepatocellular carcinoma by regulating vimentin

    PubMed Central

    CHANG, LEI; LI, CUICUI; LAN, TIAN; WU, LONG; YUAN, YUFENG; LIU, QUANYAN; LIU, ZHISU

    2016-01-01

    Hepatocellular carcinoma (HCC) is the third leading cause of cancer-related mortality worldwide. Recent studies have demonstrated that long non-coding RNAs (lncRNAs) are key in carcinogenesis. The aim of the present study was to investigate the role of lncRNA GAS5 in HCC tissues and to define the role of growth arrest-specific 5 (GAS5) in the regulation of hepatoma cell proliferation, invasion and apoptosis. Quantitative polymerase chain reaction and in situ hybridization were performed to investigate the expression of GAS5 in tumor tissues and corresponding adjacent tissues from 50 patients with HCC. Low expression of GAS5 was significantly correlated with differentiation (P<0.010) and portal vein tumor thrombosis (P=0.001). Multivariate analysis indicated that GAS5 expression was an independent predictor for overall survival (P=0.017). Further experiments demonstrated that overexpression of GAS5 significantly suppressed the proliferation and invasion of hepatoma cells in vitro. Overexpression of GAS5 significantly promoted the apoptosis of hepatoma cells. In addition, it was demonstrated that GAS5 negatively regulates vimentin expression in vitro and in vivo. Notably, vimentin knockdown promoted GAS5-pcDNA3.1-inhibition of hepatoma cell proliferation. In conclusion, the present study suggests an important role of GAS5 in the molecular etiology of HCC and suggests the potential application of GAS5 in HCC therapy. PMID:26707238

  10. Inhibitory effect of berberine on the invasion of human lung cancer cells via decreased productions of urokinase-plasminogen activator and matrix metalloproteinase-2

    SciTech Connect

    Peng, P.-L.; Hsieh, Y.-S.; Wang, C.-J.; Hsu, J.-L.; Chou, F.-P. . E-mail: fpchou@csmu.edu.tw

    2006-07-01

    Berberine, a compound isolated from medicinal herbs, has been reported with many pharmacological effects related to anti-cancer and anti-inflammation capabilities. In this study, we observed that berberine exerted a dose- and time-dependent inhibitory effect on the motility and invasion ability of a highly metastatic A549 cells under non-cytotoxic concentrations. In cancer cell migration and invasion process, matrix-degrading proteinases are required. A549 cell treated with berberine at various concentrations showed reduced ECM proteinases including matrix metalloproteinase-2 (MMP2) and urokinase-plasminogen activator (u-PA) by gelatin and casein zymography analysis. The inhibitory effect is likely to be at the transcriptional level, since the reduction in the transcripts levels was corresponding to the proteins. Moreover, berberine also exerted its action via regulating tissue inhibitor of metalloproteinase-2 (TIMP-2) and urokinase-plasminogen activator inhibitor (PAI). The upstream mediators of the effect involved c-jun, c-fos and NF-{kappa}B, as evidenced by reduced phosphorylation of the proteins. These findings suggest that berberine possesses an anti-metastatic effect in non-small lung cancer cell and may, therefore, be helpful in clinical treatment.

  11. Effects of invasive plants on arthropods.

    PubMed

    Litt, Andrea R; Cord, Erin E; Fulbright, Timothy E; Schuster, Greta L

    2014-12-01

    Non-native plants have invaded nearly all ecosystems and represent a major component of global ecological change. Plant invasions frequently change the composition and structure of vegetation communities, which can alter animal communities and ecosystem processes. We reviewed 87 articles published in the peer-reviewed literature to evaluate responses of arthropod communities and functional groups to non-native invasive plants. Total abundance of arthropods decreased in 62% of studies and increased in 15%. Taxonomic richness decreased in 48% of studies and increased in 13%. Herbivorous arthropods decreased in response to plant invasions in 48% of studies and increased in 17%, likely due to direct effects of decreased plant diversity. Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect indirect effects due to reductions in prey. Twenty-two percent of studies documented increases in predators, which may reflect changes in vegetation structure that improved mobility, survival, or web-building for these species. Detritivores increased in 67% of studies, likely in response to increased litter and decaying vegetation; no studies documented decreased abundance in this functional group. Although many researchers have examined effects of plant invasions on arthropods, sizeable information gaps remain, specifically regarding how invasive plants influence habitat and dietary requirements. Beyond this, the ability to predict changes in arthropod populations and communities associated with plant invasions could be improved by adopting a more functional and mechanistic approach. Understanding responses of arthropods to invasive plants will critically inform conservation of virtually all biodiversity and ecological processes because so many organisms depend on arthropods as prey or for their functional roles, including pollination, seed dispersal, and decomposition. Given their short generation times and ability to respond rapidly to

  12. Effects of invasive plants on arthropods.

    PubMed

    Litt, Andrea R; Cord, Erin E; Fulbright, Timothy E; Schuster, Greta L

    2014-12-01

    Non-native plants have invaded nearly all ecosystems and represent a major component of global ecological change. Plant invasions frequently change the composition and structure of vegetation communities, which can alter animal communities and ecosystem processes. We reviewed 87 articles published in the peer-reviewed literature to evaluate responses of arthropod communities and functional groups to non-native invasive plants. Total abundance of arthropods decreased in 62% of studies and increased in 15%. Taxonomic richness decreased in 48% of studies and increased in 13%. Herbivorous arthropods decreased in response to plant invasions in 48% of studies and increased in 17%, likely due to direct effects of decreased plant diversity. Predaceous arthropods decreased in response to invasive plants in 44% of studies, which may reflect indirect effects due to reductions in prey. Twenty-two percent of studies documented increases in predators, which may reflect changes in vegetation structure that improved mobility, survival, or web-building for these species. Detritivores increased in 67% of studies, likely in response to increased litter and decaying vegetation; no studies documented decreased abundance in this functional group. Although many researchers have examined effects of plant invasions on arthropods, sizeable information gaps remain, specifically regarding how invasive plants influence habitat and dietary requirements. Beyond this, the ability to predict changes in arthropod populations and communities associated with plant invasions could be improved by adopting a more functional and mechanistic approach. Understanding responses of arthropods to invasive plants will critically inform conservation of virtually all biodiversity and ecological processes because so many organisms depend on arthropods as prey or for their functional roles, including pollination, seed dispersal, and decomposition. Given their short generation times and ability to respond rapidly to

  13. High diversity of non-sporulating moulds in respiratory specimens of immunocompromised patients: should all the species be reported when diagnosing invasive aspergillosis?

    PubMed

    Garcia-Hermoso, Dea; Alanio, Alexandre; Cabaret, Odile; Olivi, Martine; Foulet, Françoise; Cordonnier, Catherine; Costa, Jean-Marc; Bretagne, Stéphane

    2015-09-01

    Non-sporulating moulds (NSMs) isolated from respiratory specimens are usually discarded without further testing although they may have pathogenic effects in immunocompromised patients. The objective of this study was to determine the identity and frequency of NSMs in patients with haematological malignancies. We analysed the mycological results of 251 consecutive respiratory samples from 104 haematology patients. Yeast and sporulating moulds were identified at the genus/species level according to their phenotypic features. NSMs were identified by internal transcribed spacer (ITS) sequencing. We detected 179 positive samples, of which 10.1% (18/179) were mixtures of moulds and 26.3% (47/179) were mixtures of moulds and yeast. We identified 142 moulds belonging to 11 different genera/species or groups, with Aspergillus fumigatus (n = 50), Penicillium spp. (n = 31) and NSM (n = 24) being the most frequently isolated species. Twenty-two NSMs were successfully sequenced: 18 were basidiomycetes and six were ascomycetes, corresponding to 16 different genera/species. NSMs were isolated with A. fumigatus in the same sample or in a subsequent sample in five patients with probable invasive aspergillosis. The conclusion is that the respiratory specimens of immunocompromised patients frequently contain very diverse mould species that may increase the virulence of pathogenic species. Reporting all mould species isolated when diagnosing invasive fungal infection could test this hypothesis.

  14. Dasatinib inhibits migration and invasion in diverse human sarcoma cell lines and induces apoptosis in bone sarcoma cells dependent on SRC kinase for survival.

    PubMed

    Shor, Audrey C; Keschman, Elizabeth A; Lee, Francis Y; Muro-Cacho, Carlos; Letson, G Douglas; Trent, Jonathan C; Pledger, W Jack; Jove, Richard

    2007-03-15

    Sarcomas are rare malignant mesenchymal tumors for which there are limited treatment options. One potential molecular target for sarcoma treatment is the Src tyrosine kinase. Dasatinib (BMS-354825), a small-molecule inhibitor of Src kinase activity, is a promising cancer therapeutic agent with p.o. bioavailability. Dasatinib exhibits antitumor effects in cultured human cell lines derived from epithelial tumors, including prostate and lung carcinomas. However, the action of dasatinib in mesenchymally derived tumors has yet to be shown. Based on our previous findings of Src activation in human sarcomas, we evaluated the effects of dasatinib in 12 cultured human sarcoma cell lines derived from bone and soft tissue sarcomas. Dasatinib inhibited Src kinase activity at nanomolar concentrations in these sarcoma cell lines. Downstream components of Src signaling, including focal adhesion kinase and Crk-associated substrate (p130(CAS)), were also inhibited at similar concentrations. This inhibition of Src signaling was accompanied by blockade of cell migration and invasion. Moreover, apoptosis was induced in the osteosarcoma and Ewing's subset of bone sarcomas at nanomolar concentrations of dasatinib. Inhibition of Src protein expression by small interfering RNA also induced apoptosis, indicating that these bone sarcoma cell lines are dependent on Src activity for survival. These results show that dasatinib inhibits migration and invasion of diverse sarcoma cell types and selectively blocks the survival of bone sarcoma cells. Therefore, dasatinib may provide therapeutic benefit by preventing the growth and metastasis of sarcomas in patients.

  15. Activation of Estrogen Receptor Transfected into a Receptor-Negative Brest Cancer Cell Line Decreases the Metastatic and Invasive Potential of the Cells

    NASA Astrophysics Data System (ADS)

    Garcia, Marcel; Derocq, Danielle; Freiss, Gilles; Rochefort, Henri

    1992-12-01

    Breast cancers containing estrogen receptors are responsive to antiestrogen treatment and have a better prognosis than estrogen receptor-negative tumors. The loss of estrogen and progesterone receptors appears to be associated with a progression to less-differentiated tumors. We transfected the human estrogen receptor into the estrogen receptor-negative metastatic breast cancer cell line MDA-MB-231 in an attempt to restore their sensitivity to antiestrogens. Two stable sublines of MDA-MB-231 cells (HC1 and HE5) expressing functional estrogen receptors were studied for their ability to grow and invade in vitro and to metastasize in athymic nude mice. The number and size of lung metastases developed by these two sublines in ovariectomized nude mice was not markedly altered by tamoxifen but was inhibited 3-fold by estradiol. Estradiol also significantly inhibited in vitro cell proliferation of these sublines and their invasiveness in Matrigel, a reconstituted basement membrane, whereas the antiestrogens 4-hydroxytamoxifen and ICI 164,384 reversed these effects. These results show that estradiol inhibits the metastatic ability of estrogen receptornegative breast cancer cells following transfection with the estrogen receptor, whereas estrogen receptor-positive breast cancers are stimulated by estrogen, indicating that factors other than the estrogen receptor are involved in progression toward hormone independence. Reactivation or transfer of the estrogen receptor gene can therefore be considered as therapeutic approaches to hormone-independent cancers

  16. Huaier restrains proliferative and invasive potential of human hepatoma SKHEP-1 cells partially through decreased Lamin B1 and elevated NOV

    PubMed Central

    Hu, Zhongdong; Yang, Ailin; Su, Guozhu; Zhao, Yunfang; Wang, Ying; Chai, Xingyun; Tu, Pengfei

    2016-01-01

    Hepatocellular carcinoma (HCC) is one of the most common cause of malignancy-related mortality worldwide. It is urgently needed to develop potential drugs with good efficacy and low toxicity for HCC treatment. The anti-tumor effect of Traditional Chinese Medicine (TCM) has received increasing attention worldwide. Trametes robiniophila Murr. (Huaier) has been used in TCM for approximately 1,600 years. Clinically, Huaier has satisfactory therapeutic effects in cancer treatment, especially in HCC. However, the mechanisms underlying the anti-cancer effect of Huaier remain ill defined. Herein we have demonstrated that Huaier dramatically inhibited cell proliferation and induced apoptosis in human hepatoma cell line SKHEP-1. Importantly, Huaier restrained the metastatic capability of SKHEP-1 cells. Mechanistically, down-regulation of Lamin B1 and up-regulation of Nephroblastoma overexpressed (NOV) were at least partially responsible for the inhibitory effect of Huaier on the proliferative and invasive capacity of SKHEP-1 cells. Our finding provided new insights into mechanisms of anti-HCC effect of Huaier and suggested a new scientific basis for clinical medication. PMID:27503760

  17. Dynamics of an experimental microbial invasion.

    PubMed

    Acosta, Francisco; Zamor, Richard M; Najar, Fares Z; Roe, Bruce A; Hambright, K David

    2015-09-15

    The ecological dynamics underlying species invasions have been a major focus of research in macroorganisms for the last five decades. However, we still know little about the processes behind invasion by unicellular organisms. To expand our knowledge of microbial invasions, we studied the roles of propagule pressure, nutrient supply, and biotic resistance in the invasion success of a freshwater invasive alga, Prymnesium parvum, using microcosms containing natural freshwater microbial assemblages. Microcosms were subjected to a factorial design with two levels of nutrient-induced diversity and three levels of propagule pressure, and incubated for 7 d, during which P. parvum densities and microbial community composition were tracked. Successful invasion occurred in microcosms receiving high propagule pressure whereas nutrients or community diversity played no role in invasion success. Invaded communities experienced distinctive changes in composition compared with communities where the invasion was unsuccessful. Successfully invaded microbial communities had an increased abundance of fungi and ciliates, and decreased abundances of diatoms and cercozoans. Many of these changes mirrored the microbial community changes detected during a natural P. parvum bloom in the source system. This role of propagule pressure is particularly relevant for P. parvum in the reservoir-dominated southern United States because this species can form large, sustained blooms that can generate intense propagule pressures for downstream sites. Human impact and global climate change are currently causing widespread environmental changes in most southern US freshwater systems that may facilitate P. parvum establishment and, when coupled with strong propagule pressure, could put many more systems at risk for invasion. PMID:26324928

  18. Dynamics of an experimental microbial invasion

    PubMed Central

    Acosta, Francisco; Zamor, Richard M.; Najar, Fares Z.; Roe, Bruce A.; Hambright, K. David

    2015-01-01

    The ecological dynamics underlying species invasions have been a major focus of research in macroorganisms for the last five decades. However, we still know little about the processes behind invasion by unicellular organisms. To expand our knowledge of microbial invasions, we studied the roles of propagule pressure, nutrient supply, and biotic resistance in the invasion success of a freshwater invasive alga, Prymnesium parvum, using microcosms containing natural freshwater microbial assemblages. Microcosms were subjected to a factorial design with two levels of nutrient-induced diversity and three levels of propagule pressure, and incubated for 7 d, during which P. parvum densities and microbial community composition were tracked. Successful invasion occurred in microcosms receiving high propagule pressure whereas nutrients or community diversity played no role in invasion success. Invaded communities experienced distinctive changes in composition compared with communities where the invasion was unsuccessful. Successfully invaded microbial communities had an increased abundance of fungi and ciliates, and decreased abundances of diatoms and cercozoans. Many of these changes mirrored the microbial community changes detected during a natural P. parvum bloom in the source system. This role of propagule pressure is particularly relevant for P. parvum in the reservoir-dominated southern United States because this species can form large, sustained blooms that can generate intense propagule pressures for downstream sites. Human impact and global climate change are currently causing widespread environmental changes in most southern US freshwater systems that may facilitate P. parvum establishment and, when coupled with strong propagule pressure, could put many more systems at risk for invasion. PMID:26324928

  19. TR4 nuclear receptor increases prostate cancer invasion via decreasing the miR-373-3p expression to alter TGFβR2/p-Smad3 signals.

    PubMed

    Qiu, Xiaofu; Zhu, Jin; Sun, Yin; Fan, Kun; Yang, Dong-Rong; Li, Gonghui; Yang, Guosheng; Chang, Chawnshang

    2015-06-20

    Testicular nuclear receptor 4 (TR4), a member of the nuclear receptor superfamily, may play important roles to modulate the metabolic diseases and prostate tumorigenesis. Here we found TR4 could increase prostate cancer (PCa) cell invasion. Mechanism dissection revealed that TR4 might increase PCa cell invasion via decreasing the miR-373-3p expression that resulted in the activation of the TGFβR2/p-Smad3 signals. The in vivo mouse model using orthotopically xenografted CWR22Rv1 cell line transfected with luciferase-reporter confirmed in vitro cell line studies showing TR4 increased PCa metastasis via decreasing the miR-373-3p expression. Together, these data suggest that TR4 may increase PCa metastasis via a newly identified signal and targeting these TR4/miR-473-3p/TGFβR2/p-Smad3 signals using TR4 antagonist or TR4-siRNA or miR-373-3p may allow us to develop a new potential therapeutic approach to better suppress PCa metastasis.

  20. Genetic monitoring detects an overlooked cryptic species and reveals the diversity and distribution of three invasive Rattus congeners in south Africa

    PubMed Central

    2011-01-01

    Background South Africa's long and extensive trade activity has ensured ample opportunities for exotic species introduction. Whereas the rich biodiversity of endemic southern African fauna has been the focus of many studies, invasive vertebrates are generally overlooked despite potential impacts on biodiversity, health and agriculture. Genetic monitoring of commensal rodents in South Africa which uncovered the presence of Rattus tanezumi, a South-East Asian endemic not previously known to occur in Africa, provided the impetus for expanded studies on all invasive Rattus species present. Results To this end, intensified sampling at 28 South African localities and at one site in Swaziland, identified 149 Rattus specimens. Cytochrome b gene sequencing revealed the presence of two R. tanezumi, seven Rattus rattus and five Rattus norvegicus haplotypes in south Africa. Phylogenetic results were consistent with a single, recent R. tanezumi introduction and indicated that R. norvegicus and R. rattus probably became established following at least two and three independent introductions, respectively. Intra- and inter-specific diversity was highest in informal human settlements, with all three species occurring at a single metropolitan township site. Rattus norvegicus and R. rattus each occurred sympatrically with Rattus tanezumi at one and five sites, respectively. Karyotyping of selected R. rattus and R. tanezumi individuals identified diploid numbers consistent with those reported previously for these cryptic species. Ordination of bioclimatic variables and MaxEnt ecological niche modelling confirmed that the bioclimatic niche occupied by R. tanezumi in south Africa was distinct from that occupied in its naturalised range in south-east Asia suggesting that factors other than climate may influence the distribution of this species. Conclusions This study has highlighted the value of genetic typing for detecting cryptic invasive species, providing historical insights into

  1. Endosymbiotic and Host Proteases in the Digestive Tract of the Invasive Snail Pomacea canaliculata: Diversity, Origin and Characterization

    PubMed Central

    Godoy, Martín S.; Castro-Vasquez, Alfredo; Vega, Israel A.

    2013-01-01

    Digestive proteases of the digestive tract of the apple snail Pomacea canaliculata were studied. Luminal protease activity was found in the crop, the style sac and the coiled gut and was significantly higher in the coiled gut. Several protease bands and their apparent molecular weights were identified in both tissue extracts and luminal contents by gel zymography: (1) a 125 kDa protease in salivary gland extracts and in the crop content; (2) a 30 kDa protease throughout all studied luminal contents and in extracts of the midgut gland and of the endosymbionts isolated from this gland; (3) two proteases of 145 and 198 kDa in the coiled gut content. All these proteases were inhibited by aprotinin, a serine-protease inhibitor, and showed maximum activity between 30°C and 35°C and pH between 8.5 and 9.5. Tissue L-alanine-N-aminopeptidase activity was determined in the wall of the crop, the style sac and the coiled gut and was significantly higher in the coiled gut. Our findings show that protein digestion in P. canaliculata is carried out through a battery of diverse proteases originated from the salivary glands and the endosymbionts lodged in the midgut gland and by proteases of uncertain origin that occur in the coiled gut lumen. PMID:23818959

  2. Endosymbiotic and host proteases in the digestive tract of the invasive snail Pomacea canaliculata: diversity, origin and characterization.

    PubMed

    Godoy, Martín S; Castro-Vazquez, Alfredo; Castro-Vasquez, Alfredo; Vega, Israel A

    2013-01-01

    Digestive proteases of the digestive tract of the apple snail Pomacea canaliculata were studied. Luminal protease activity was found in the crop, the style sac and the coiled gut and was significantly higher in the coiled gut. Several protease bands and their apparent molecular weights were identified in both tissue extracts and luminal contents by gel zymography: (1) a 125 kDa protease in salivary gland extracts and in the crop content; (2) a 30 kDa protease throughout all studied luminal contents and in extracts of the midgut gland and of the endosymbionts isolated from this gland; (3) two proteases of 145 and 198 kDa in the coiled gut content. All these proteases were inhibited by aprotinin, a serine-protease inhibitor, and showed maximum activity between 30°C and 35°C and pH between 8.5 and 9.5. Tissue L-alanine-N-aminopeptidase activity was determined in the wall of the crop, the style sac and the coiled gut and was significantly higher in the coiled gut. Our findings show that protein digestion in P. canaliculata is carried out through a battery of diverse proteases originated from the salivary glands and the endosymbionts lodged in the midgut gland and by proteases of uncertain origin that occur in the coiled gut lumen.

  3. Insight into the routes of Wolbachia invasion: high levels of horizontal transfer in the spider genus Agelenopsis revealed by Wolbachia strain and mitochondrial DNA diversity.

    PubMed

    Baldo, Laura; Ayoub, Nadia A; Hayashi, Cheryl Y; Russell, Jacob A; Stahlhut, Julie K; Werren, John H

    2008-01-01

    The pandemic distribution of Wolbachia (alpha-proteobacteria) across arthropods is largely due to the ability of these maternally inherited endosymbionts to successfully shift hosts across species boundaries. Yet it remains unclear whether Wolbachia has preferential routes of transfer among species. Here, we examined populations of eight species of the North American funnel-web spider genus Agelenopsis to evaluate whether Wolbachia show evidence for host specificity and the relative contribution of horizontal vs. vertical transmission of strains within and among related host species. Wolbachia strains were characterized by multilocus sequence typing (MLST) and Wolbachia surface protein (WSP) sequences, and analysed in relation to host phylogeny, mitochondrial diversity and geographical range. Results indicate that at least three sets of divergent Wolbachia strains invaded the genus Agelenopsis. After each invasion, the Wolbachia strains preferentially shuffled across species of this host genus by horizontal transfer rather than cospeciation. Decoupling of Wolbachia and host mitochondrial haplotype (mitotypes) evolutionary histories within single species reveals an extensive contribution of horizontal transfer also in the rapid dispersal of Wolbachia among conspecific host populations. These findings provide some of the strongest evidence to support the association of related Wolbachia strains with related hosts by means of both vertical and horizontal strain transmission. Similar analyses across a broader range of invertebrate taxa are needed, using sensitive methods for strain typing such as MLST, to determine if this pattern of Wolbachia dispersal is peculiar to Agelenopsis (or spiders), or is in fact a general pattern in arthropods.

  4. Impacts of invasive plants on resident animals across ecosystems, taxa, and feeding types: a global assessment.

    PubMed

    Schirmel, Jens; Bundschuh, Mirco; Entling, Martin H; Kowarik, Ingo; Buchholz, Sascha

    2016-02-01

    As drivers of global change, biological invasions have fundamental ecological consequences. However, it remains unclear how invasive plant effects on resident animals vary across ecosystems, animal classes, and functional groups. We performed a comprehensive meta-analysis covering 198 field and laboratory studies reporting a total of 3624 observations of invasive plant effects on animals. Invasive plants had reducing (56%) or neutral (44%) effects on animal abundance, diversity, fitness, and ecosystem function across different ecosystems, animal classes, and feeding types while we could not find any increasing effect. Most importantly, we found that invasive plants reduced overall animal abundance, diversity and fitness. However, this significant overall effect was contingent on ecosystems, taxa, and feeding types of animals. Decreasing effects of invasive plants were most evident in riparian ecosystems, possibly because frequent disturbance facilitates more intense plant invasions compared to other ecosystem types. In accordance with their immediate reliance on plants for food, invasive plant effects were strongest on herbivores. Regarding taxonomic groups, birds and insects were most strongly affected. In insects, this may be explained by their high frequency of herbivory, while birds demonstrate that invasive plant effects can also cascade up to secondary consumers. Since data on impacts of invasive plants are rather limited for many animal groups in most ecosystems, we argue for overcoming gaps in knowledge and for a more differentiated discussion on effects of invasive plant on native fauna.

  5. An extreme cytoplasmic bottleneck in the modern European cultivated potato (Solanum tuberosum) is not reflected in decreased levels of nuclear diversity

    PubMed Central

    Provan, J.; Powell, W; Dewar, H.; Bryan, G.; Machray, G. C.; Waugh, R.

    1999-01-01

    We have used the polymorphic chloroplast (cp) and nuclear simple sequence repeats (SSRs) to analyse levels of cytoplasmic and nuclear diversity in the gene pool of the European cultivated potato (Solanum tuberosum ssp. tuberosum). Primers designed from the complete chloroplast sequence of tobacco (Nicotiana tabacum) were used to amplify polymorphic products in a range of potato cultivars. Combining the data from seven polymorphic cpSSR loci gave 26 haplotypes, one of which (haplotype A) accounted for 151 out of the 178 individuals studied and corresponded to the T-type cytoplasm previously identified in cultivated potatoes using chloroplast restriction fragment length polymorphism analysis. Phylogenetic and diversity analyses of the relationships between cpSSR haplotypes confirmed much higher levels of cytoplasmic diversity outwith the T-type group. Diversity levels at eight nuclear SSR loci, however, were not significantly different between cytoplasmic groups, suggesting a severe maternal bottleneck in the evolution of the modern cultivated potato. These results highlight the importance in quantifying levels of cytoplasmic as well as nuclear diversity and confirm the need for a change in breeding practices to increase levels of non-T-type cytoplasm in the cultivated gene pool, thus helping reduce problems associated with pollen sterility. This may be facilitated by germplasm analysis using cpSSRs, which will allow efficient selection of diverse cytoplasm donors.

  6. Genomic comparison of multi-drug resistant invasive and colonizing Acinetobacter baumannii isolated from diverse human body sites reveals genomic plasticity

    PubMed Central

    2011-01-01

    Background Acinetobacter baumannii has recently emerged as a significant global pathogen, with a surprisingly rapid acquisition of antibiotic resistance and spread within hospitals and health care institutions. This study examines the genomic content of three A. baumannii strains isolated from distinct body sites. Isolates from blood, peri-anal, and wound sources were examined in an attempt to identify genetic features that could be correlated to each isolation source. Results Pulsed-field gel electrophoresis, multi-locus sequence typing and antibiotic resistance profiles demonstrated genotypic and phenotypic variation. Each isolate was sequenced to high-quality draft status, which allowed for comparative genomic analyses with existing A. baumannii genomes. A high resolution, whole genome alignment method detailed the phylogenetic relationships of sequenced A. baumannii and found no correlation between phylogeny and body site of isolation. This method identified genomic regions unique to both those isolates found on the surface of the skin or in wounds, termed colonization isolates, and those identified from body fluids, termed invasive isolates; these regions may play a role in the pathogenesis and spread of this important pathogen. A PCR-based screen of 74 A. baumanii isolates demonstrated that these unique genes are not exclusive to either phenotype or isolation source; however, a conserved genomic region exclusive to all sequenced A. baumannii was identified and verified. Conclusions The results of the comparative genome analysis and PCR assay show that A. baumannii is a diverse and genomically variable pathogen that appears to have the potential to cause a range of human disease regardless of the isolation source. PMID:21639920

  7. Decrease in diversity and changes in community composition of arbuscular mycorrhizal fungi in roots of apple trees with increasing orchard management intensity across a regional scale.

    PubMed

    van Geel, Maarten; Ceustermans, An; van Hemelrijck, Wendy; Lievens, Bart; Honnay, Olivier

    2015-02-01

    Understanding which factors drive the diversity and community composition of arbuscular mycorrhizal fungi (AMF) is important due to the role of these soil micro-organisms in ecosystem functioning and current environmental threats to AMF biodiversity. Additionally, in agro-ecosystems, this knowledge may help to evaluate their use in making agriculture more sustainable. Here, we used 454-pyrosequencing of small subunit rRNA gene amplicons to quantify AMF diversity and community composition in the roots of cultivated apple trees across 24 orchards in central Belgium. We aimed at identifying the factors (soil chemical variables, organic vs. conventional farming, and geographical location) that affect AMF diversity and community composition. In total, 110 AMF OTUs were detected, of which the majority belonged to the Glomeraceae (73%) and the Claroideoglomeraceae (19%). We show that soil characteristics and farming system, rather than the geographical location of the orchards, shape AMF communities on apple trees. Particularly, plant-available P content of the soil was associated with lower AMF diversity. In orchards with a lower plant-available P content of the soil (P < 100 mg/kg soil), we also found a significantly higher AMF diversity in organically managed orchards as compared to conventionally managed orchards. Finally, the degree of nestedness of the AMF communities was related to plant-available P and N content of the soil, pointing at a progressive loss of AMF taxa with increasing fertilization. Overall, we conclude that a combination of organic orchard management and moderate fertilization may preserve diverse AMF communities on apple trees and that AMF in the roots of apple trees appear not to be dispersal limited at the scale of central Belgium.

  8. Southern leaf blight disease severity is correlated with decreased maize leaf epiphytic bacterial species richness and the phyllosphere bacterial diversity decline is enhanced by nitrogen fertilization

    PubMed Central

    Manching, Heather C.; Balint-Kurti, Peter J.; Stapleton, Ann E.

    2014-01-01

    Plant leaves are inhabited by a diverse group of microorganisms that are important contributors to optimal growth. Biotic and abiotic effects on plant growth are usually studied in controlled settings examining response to variation in single factors and in field settings with large numbers of variables. Multi-factor experiments with combinations of stresses bridge this gap, increasing our understanding of the genotype-environment-phenotype functional map for the host plant and the affiliated epiphytic community. The maize inbred B73 was exposed to single and combination abiotic and the biotic stress treatments: low nitrogen fertilizer and high levels of infection with southern leaf blight (causal agent Cochliobolus heterostrophus). Microbial epiphyte samples were collected at the vegetative early-season phase and species composition was determined using 16S ribosomal intergenic spacer analysis. Plant traits and level of southern leaf blight disease were measured late-season. Bacterial diversity was different among stress treatment groups (P < 0.001). Lower species richness—alpha diversity—was correlated with increased severity of southern leaf blight disease when disease pressure was high. Nitrogen fertilization intensified the decline in bacterial alpha diversity. While no single bacterial ribotype was consistently associated with disease severity, small sets of ribotypes were good predictors of disease levels. Difference in leaf bacterial-epiphyte diversity early in the season were correlated with plant disease severity, supporting further tests of microbial epiphyte-disease correlations for use in predicting disease progression. PMID:25177328

  9. Exposure to soil, house dust and decaying plants increases gut microbial diversity and decreases serum immunoglobulin E levels in BALB/c mice.

    PubMed

    Zhou, Dongrui; Zhang, Honglin; Bai, Zhimao; Zhang, Aidi; Bai, Futian; Luo, Xing; Hou, Yue; Ding, Xiao; Sun, Beili; Sun, Xiao; Ma, Ning; Wang, Cuifen; Dai, Xiaoniu; Lu, Zuhong

    2016-05-01

    To assess the impact of sanitation of a living environment on gut microbiota and development of the immune system, we raised BALB/c mice under three distinct environmental conditions: a specific pathogen-free animal room (SPF), a general animal room (XZ) and a farmhouse (JD). All other variables like diet, age, genetic background, physiological status and original gut microbiota were controlled for in the three groups. Using high-throughput sequencing of the 16S rRNA gene, we found that each mouse group had a specific structure of the gut microbial community. Groups JD and XZ harboured a significantly more diverse and richer gut microbiota than did group SPF. Bacteroidetes were significantly more abundant in groups XZ and JD than in group SPF, whereas Firmicutes showed the inverse pattern. Total serum immunoglobulin E (IgE) levels were significantly lower in groups XZ and JD than in group SPF. There were no significant differences in gut microbiota diversity and serum IgE concentration between groups JD and XZ, but we found higher abundance of dominant genera in the gut microflora of group JD. We conclude that exposure to soil, house dust and decaying plant material enhances gut microbial diversity and innate immunity. Our results seem to provide new evidence supporting the hygiene hypothesis.

  10. Resource competition in plant invasions: emerging patterns and research needs.

    PubMed

    Gioria, Margherita; Osborne, Bruce A

    2014-01-01

    Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species.

  11. Resource competition in plant invasions: emerging patterns and research needs

    PubMed Central

    Gioria, Margherita; Osborne, Bruce A.

    2014-01-01

    Invasions by alien plants provide a unique opportunity to examine competitive interactions among plants. While resource competition has long been regarded as a major mechanism responsible for successful invasions, given a well-known capacity for many invaders to become dominant and reduce plant diversity in the invaded communities, few studies have measured resource competition directly or have assessed its importance relative to that of other mechanisms, at different stages of an invasion process. Here, we review evidence comparing the competitive ability of invasive species vs. that of co-occurring native plants, along a range of environmental gradients, showing that many invasive species have a superior competitive ability over native species, although invasive congeners are not necessarily competitively superior over native congeners, nor are alien dominants are better competitors than native dominants. We discuss how the outcomes of competition depend on a number of factors, such as the heterogeneous distribution of resources, the stage of the invasion process, as well as phenotypic plasticity and evolutionary adaptation, which may result in increased or decreased competitive ability in both invasive and native species. Competitive advantages of invasive species over natives are often transient and only important at the early stages of an invasion process. It remains unclear how important resource competition is relative to other mechanisms (competition avoidance via phenological differences, niche differentiation in space associated with phylogenetic distance, recruitment and dispersal limitation, indirect competition, and allelopathy). Finally, we identify the conceptual and methodological issues characterizing competition studies in plant invasions, and we discuss future research needs, including examination of resource competition dynamics and the impact of global environmental change on competitive interactions between invasive and native species. PMID

  12. Quinolone-resistance in Salmonella is associated with decreased mRNA expression of virulence genes invA and avrA, growth and intracellular invasion and survival.

    PubMed

    Wang, Yu-Ping; Li, Lin; Shen, Jian-Zhong; Yang, Fu-Jiang; Wu, Yong-Ning

    2009-02-01

    A variety of environmental factors, such as oxygen, pH, osmolarity and antimicrobial agents, modulate the expression of Salmonella pathogenicity islands (SPI) genes. This study investigated SPI-1 gene expression and the pathogenicity of quinolone-resistant Salmonella. mRNA expression levels of the invA and avrA genes, located in SPI-1, in quinolone-susceptible and quinolone-resistant Salmonella strains were determined using real-time fluorescent quantitative reverse transcription-polymerase chain reaction (RT-PCR). Twenty-five quinolone-resistant Salmonella mutants were derived from quinolone-susceptible strains by multiple-passage selection through increasing concentrations of ciprofloxacin in vitro, while an additional 15 strains were quinolone-resistant Salmonella clinical isolates. Sequence analysis showed no gene deletion or point mutations of nine SPI-1 genes (including invA and avrA) occurred in either the selected or clinical quinolone-resistant strains, while a single gyrA point mutation (S83F) was observed in all 40 quinolone-resistant strains. The mRNA expression levels of invA and avrA were significantly decreased (P<0.005) in quinolone-resistant strains (clinically acquired or experimentally selected in vitro), compared to the quinolone-susceptible strains. The resistant strains also had a slower growth rate combined with decreased epithelial cell invasion and intracellular replication in epithelial cells and macrophages. The results suggest that quinolone-resistance may be associated with lower virulence and pathogenicity than in quinolone-susceptible strains.

  13. Streptozotocin-induced type-1-diabetes disease onset in Sprague-Dawley rats is associated with an altered intestinal microbiota composition and decreased diversity.

    PubMed

    Patterson, Elaine; Marques, Tatiana M; O'Sullivan, Orla; Fitzgerald, Patrick; Fitzgerald, Gerald F; Cotter, Paul D; Dinan, Timothy G; Cryan, John F; Stanton, Catherine; Ross, R Paul

    2015-01-01

    There is a growing appreciation that microbiota composition can significantly affect host health and play a role in disease onset and progression. This study assessed the impact of streptozotocin (STZ)-induced type-1-diabetes (T1D) on intestinal microbiota composition and diversity in Sprague-Dawley rats, compared with healthy controls over time. T1D was induced by injection of a single dose (60 mg STZ kg(-1)) of STZ, administered via the intraperitoneal cavity. Total DNA was isolated from faecal pellets at weeks 0 (pre-STZ injection), 1, 2 and 4 and from caecal content at week 5 from both healthy and T1D groups. High-throughput 16S rRNA sequencing was employed to investigate intestinal microbiota composition. The data revealed that although intestinal microbiota composition between the groups was similar at week 0, a dramatic impact of T1D development on the microbiota was apparent post-STZ injection and for up to 5 weeks. Most notably, T1D onset was associated with a shift in the Bacteroidetes : Firmicutes ratio (P<0.05), while at the genus level, increased proportions of lactic acid producing bacteria such as Lactobacillus and Bifidobacterium were associated with the later stages of T1D progression (P<0.05). Coincidently, T1D increased caecal lactate levels (P<0.05). Microbial diversity was also reduced following T1D (P<0.05). Principle co-ordinate analyses demonstrated temporal clustering in T1D and control groups with distinct separation between groups. The results provide a comprehensive account of how T1D is associated with an altered intestinal microbiota composition and reduced microbial diversity over time.

  14. Investigating Invasives

    ERIC Educational Resources Information Center

    Lightbody, Mary

    2008-01-01

    Invasive species, commonly known as "invasives," are nonnative plants, animals, and microbes that completely take over and change an established ecosystem. The consequences of invasives' spread are significant. In fact, many of the species that appear on the Endangered Species list are threatened by invasives. Therefore, the topic of invasive…

  15. The importance of quantifying propagule pressure to understand invasion: an examination of riparian forest invasibility.

    PubMed

    Eschtruth, Anne K; Battles, John J

    2011-06-01

    The widely held belief that riparian communities are highly invasible to exotic plants is based primarily on comparisons of the extent of invasion in riparian and upland communities. However, because differences in the extent of invasion may simply result from variation in propagule supply among recipient environments, true comparisons of invasibility require that both invasion success and propagule pressure are quantified. In this study, we quantified propagule pressure in order to compare the invasibility of riparian and upland forests and assess the accuracy of using a community's level of invasion as a surrogate for its invasibility. We found the extent of invasion to be a poor proxy for invasibility. The higher level of invasion in the studied riparian forests resulted from greater propagule availability rather than higher invasibility. Furthermore, failure to account for propagule pressure may confound our understanding of general invasion theories. Ecological theory suggests that species-rich communities should be less invasible. However, we found significant relationships between species diversity and invasion extent, but no diversity-invasibility relationship was detected for any species. Our results demonstrate that using a community's level of invasion as a surrogate for its invasibility can confound our understanding of invasibility and its determinants.

  16. Invasive blue mussels threaten regional scale genetic diversity in mainland and remote offshore locations: the need for baseline data and enhanced protection in the Southern Ocean.

    PubMed

    Gardner, Jonathan P A; Zbawicka, Małgorzata; Westfall, Kristen M; Wenne, Roman

    2016-09-01

    Human-mediated biological transfers of species have substantially modified many ecosystems with profound environmental and economic consequences. However, in many cases, invasion events are very hard to identify because of the absence of an appropriate baseline of information for receiving sites/regions. In this study, use of high-resolution genetic markers (single nucleotide polymorphisms - SNPs) highlights the threat of introduced Northern Hemisphere blue mussels (Mytilus galloprovincialis) at a regional scale to Southern Hemisphere lineages of blue mussels via hybridization and introgression. Analysis of a multispecies SNP dataset reveals hotspots of invasive Northern Hemisphere blue mussels in some mainland New Zealand locations, as well as the existence of unique native lineages of blue mussels on remote oceanic islands in the Southern Ocean that are now threatened by invasive mussels. Samples collected from an oil rig that has moved between South Africa, Australia, and New Zealand were identified as invasive Northern Hemisphere mussels, revealing the relative ease with which such non-native species may be moved from region to region. In combination, our results highlight the existence of unique lineages of mussels (and by extension, presumably of other taxa) on remote offshore islands in the Southern Ocean, the need for more baseline data to help identify bioinvasion events, the ongoing threat of hybridization and introgression posed by invasive species, and the need for greater protection of some of the world's last great remote areas.

  17. How Should Beta-Diversity Inform Biodiversity Conservation?

    PubMed

    Socolar, Jacob B; Gilroy, James J; Kunin, William E; Edwards, David P

    2016-01-01

    To design robust protected area networks, accurately measure species losses, or understand the processes that maintain species diversity, conservation science must consider the organization of biodiversity in space. Central is beta-diversity--the component of regional diversity that accumulates from compositional differences between local species assemblages. We review how beta-diversity is impacted by human activities, including farming, selective logging, urbanization, species invasions, overhunting, and climate change. Beta-diversity increases, decreases, or remains unchanged by these impacts, depending on the balance of processes that cause species composition to become more different (biotic heterogenization) or more similar (biotic homogenization) between sites. While maintaining high beta-diversity is not always a desirable conservation outcome, understanding beta-diversity is essential for protecting regional diversity and can directly assist conservation planning. PMID:26701706

  18. Invasive Candidiasis

    MedlinePlus

    ... Invasive candidiasis is an infection caused by a yeast (a type of fungus) called Candida . Unlike Candida ... mouth and throat (also called “thrush”) or vaginal “yeast infections,” invasive candidiasis is a serious infection that ...

  19. An Invasive Mammal (the Gray Squirrel, Sciurus carolinensis) Commonly Hosts Diverse and Atypical Genotypes of the Zoonotic Pathogen Borrelia burgdorferi Sensu Lato

    PubMed Central

    Magierecka, Agnieszka; Gilbert, Lucy; Edoff, Alissa; Brereton, Amelia; Kilbride, Elizabeth; Denwood, Matt; Birtles, Richard; Biek, Roman

    2015-01-01

    Invasive vertebrate species can act as hosts for endemic pathogens and may alter pathogen community composition and dynamics. For the zoonotic pathogen Borrelia burgdorferi sensu lato, the agent of Lyme borreliosis, recent work shows invasive rodent species can be of high epidemiological importance and may support host-specific strains. This study examined the role of gray squirrels (Sciurus carolinensis) (n = 679), an invasive species in the United Kingdom, as B. burgdorferi sensu lato hosts. We found that gray squirrels were frequently infested with Ixodes ricinus, the main vector of B. burgdorferi sensu lato in the United Kingdom, and 11.9% were infected with B. burgdorferi sensu lato. All four genospecies that occur in the United Kingdom were detected in gray squirrels, and unexpectedly, the bird-associated genospecies Borrelia garinii was most common. The second most frequent infection was with Borrelia afzelii. Genotyping of B. garinii and B. afzelii produced no evidence for strains associated with gray squirrels. Generalized linear mixed models (GLMM) identified tick infestation and date of capture as significant factors associated with B. burgdorferi sensu lato infection in gray squirrels, with infection elevated in early summer in squirrels infested with ticks. Invasive gray squirrels appear to become infected with locally circulating strains of B. burgdorferi sensu lato, and further studies are required to determine their role in community disease dynamics. Our findings highlight the fact that the role of introduced host species in B. burgdorferi sensu lato epidemiology can be highly variable and thus difficult to predict. PMID:25888168

  20. The Extent of Hybridization and Its Impact on the Genetic Diversity and Population Structure of an Invasive Tree, Ulmus Pumila (Ulmaceae)

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Siberian elm (Ulmus pumila L.), native to East Asia, was introduced in the U.S. in the 1900’s because of its high tolerance to Dutch elm disease (DED). Siberian elm has spread following its introduction and has now become one of the most invasive woody species in the U.S., alongside Russian olive a...

  1. EDAPHIC CONTROLS ON THE PHYTOCHEMISTRY OF THE INVASIVE PLANT ALLIARIA PETIOLATA

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Alliaria petiolata (garlic mustard), an invasive species in temperate forests throughout North America, is associated with decreases in above and below ground species diversity and alterations to nutrient turnover. Garlic mustard produces a set of secondary chemicals in the glucosinolate family, sp...

  2. AB173. TR4 nuclear receptor increases prostate cancer invasion via decreasing the miR-373-3p expression to alter TGFβR2/p-Smad3 signals

    PubMed Central

    Yang, Guosheng; Qiu, Xiaofo

    2016-01-01

    Objective Testicular nuclear receptor 4 (TR4) is a member of the nuclear receptor superfamily, which may play key roles to influence the metabolic diseases and prostate tumorigenesis. The purpose of our study is to elucidate the mechanisms how TR4 influences the prostate cancer (PCa) metastasis. Methods We constructed three different PCa cell lines including C4-2, PC3 and CWR22Rv1 with differential stable expression of TR4. RT-PCR and Western blot analysis were used to validate identified downstream genes. To explore the function of genes, we manipulated cells 2D and 3D invasion assays and mice experiment. Results we found TR4 could promote PCa cell invasion using two different cell invasion assays. Mechanism dissection revealed that TR4 might enhance PCa cell invasion via modulation of the microRNA-373-3p (miR-373-3p) expression. An interruption approach using miR-373-3p partially reversed TR4-enhanced PCa cell invasion. Furthermore, we found TR4-miR-373-3p might function through modulation of the TGFβR2/p-Smad3 signals to enhance the PCa cell invasion. The in vivo mouse model using orthotopic xenografted CWR22Rv1 cell line transfected with luciferase-reporter also confirmed in vitro cell line studies showing TR4 enhanced PCa metastasis via modulation of miR-373-3p. Conclusions Our data suggest that TR4 may represent a key player to influence the PCa metastasis and targeting TR4 miR-373-3p→ TGFβR2/p-Smad3 axis using TR4 antagonist or TR4-siRNA or miR-373-3p may become a new potential therapeutic approach to better suppress PCa metastasis.

  3. Uptake, outcomes, and costs of implementing non-invasive prenatal testing for Down’s syndrome into NHS maternity care: prospective cohort study in eight diverse maternity units

    PubMed Central

    Wright, David; Hill, Melissa; Verhoef, Talitha I; Daley, Rebecca; Lewis, Celine; Mason, Sarah; McKay, Fiona; Jenkins, Lucy; Howarth, Abigail; Cameron, Louise; McEwan, Alec; Fisher, Jane; Kroese, Mark; Morris, Stephen

    2016-01-01

    Objective To investigate the benefits and costs of implementing non-invasive prenatal testing (NIPT) for Down’s syndrome into the NHS maternity care pathway. Design Prospective cohort study. Setting Eight maternity units across the United Kingdom between 1 November 2013 and 28 February 2015. Participants All pregnant women with a current Down’s syndrome risk on screening of at least 1/1000. Main outcome measures Outcomes were uptake of NIPT, number of cases of Down’s syndrome detected, invasive tests performed, and miscarriages avoided. Pregnancy outcomes and costs associated with implementation of NIPT, compared with current screening, were determined using study data on NIPT uptake and invasive testing in combination with national datasets. Results NIPT was prospectively offered to 3175 pregnant women. In 934 women with a Down’s syndrome risk greater than 1/150, 695 (74.4%) chose NIPT, 166 (17.8%) chose invasive testing, and 73 (7.8%) declined further testing. Of 2241 women with risks between 1/151 and 1/1000, 1799 (80.3%) chose NIPT. Of 71 pregnancies with a confirmed diagnosis of Down’s syndrome, 13/42 (31%) with the diagnosis after NIPT and 2/29 (7%) after direct invasive testing continued, resulting in 12 live births. In an annual screening population of 698 500, offering NIPT as a contingent test to women with a Down’s syndrome screening risk of at least 1/150 would increase detection by 195 (95% uncertainty interval −34 to 480) cases with 3368 (2279 to 4027) fewer invasive tests and 17 (7 to 30) fewer procedure related miscarriages, for a non-significant difference in total costs (£−46 000, £−1 802 000 to £2 661 000). The marginal cost of NIPT testing strategies versus current screening is very sensitive to NIPT costs; at a screening threshold of 1/150, NIPT would be cheaper than current screening if it cost less than £256. Lowering the risk threshold increases the number of Down’s syndrome cases detected and

  4. 'Bigger data' on scale-dependent effects of invasive species on biodiversity cannot overcome confounded analyses: a comment on Stohlgren & Rejmánek (2014).

    PubMed

    Chase, Jonathan M; Powell, Kristin I; Knight, Tiffany M

    2015-08-01

    A recent study by Stohlgren & Rejmánek (SR: Stohlgren TJ, Rejmánek M. 2014 Biol. Lett. 10. (doi:10.1098/rsbl.2013.0939)) purported to test the generality of a recent finding of scale-dependent effects of invasive plants on native diversity; dominant invasive plants decreased the intercept and increased the slope of the species-area relationship. SR (2014) find little correlation between invasive species cover and the slopes and intercepts of SARs across a diversity of sites. We show that the analyses of SR (2014) are inappropriate because of confounding causality.

  5. 'Bigger data' on scale-dependent effects of invasive species on biodiversity cannot overcome confounded analyses: a comment on Stohlgren & Rejmánek (2014).

    PubMed

    Chase, Jonathan M; Powell, Kristin I; Knight, Tiffany M

    2015-08-01

    A recent study by Stohlgren & Rejmánek (SR: Stohlgren TJ, Rejmánek M. 2014 Biol. Lett. 10. (doi:10.1098/rsbl.2013.0939)) purported to test the generality of a recent finding of scale-dependent effects of invasive plants on native diversity; dominant invasive plants decreased the intercept and increased the slope of the species-area relationship. SR (2014) find little correlation between invasive species cover and the slopes and intercepts of SARs across a diversity of sites. We show that the analyses of SR (2014) are inappropriate because of confounding causality. PMID:26246332

  6. Epigenetic Variation May Compensate for Decreased Genetic Variation with Introductions: A Case Study Using House Sparrows (Passer domesticus) on Two Continents.

    PubMed

    Schrey, Aaron W; Coon, Courtney A C; Grispo, Michael T; Awad, Mohammed; Imboma, Titus; McCoy, Earl D; Mushinsky, Henry R; Richards, Christina L; Martin, Lynn B

    2012-01-01

    Epigenetic mechanisms impact several phenotypic traits and may be important for ecology and evolution. The introduced house sparrow (Passer domesticus) exhibits extensive phenotypic variation among and within populations. We screened methylation in populations from Kenya and Florida to determine if methylation varied among populations, varied with introduction history (Kenyan invasion <50 years old, Florida invasion ~150 years old), and could potentially compensate for decrease genetic variation with introductions. While recent literature has speculated on the importance of epigenetic effects for biological invasions, this is the first such study among wild vertebrates. Methylation was more frequent in Nairobi, and outlier loci suggest that populations may be differentiated. Methylation diversity was similar between populations, in spite of known lower genetic diversity in Nairobi, which suggests that epigenetic variation may compensate for decreased genetic diversity as a source of phenotypic variation during introduction. Our results suggest that methylation differences may be common among house sparrows, but research is needed to discern whether methylation impacts phenotypic variation.

  7. Invasion patterns of ground-dwelling arthropods in Canarian laurel forests

    NASA Astrophysics Data System (ADS)

    Arndt, Erik; Perner, Jörg

    2008-09-01

    Patterns of invasive species in four different functional groups of ground-dwelling arthropods (Carnivorous ground dwelling beetles; Chilopoda; Diplopoda; Oniscoidea) were examined in laurel forests of the Canary Islands. The following hypotheses were tested: (A) increasing species richness is connected with decreasing invasibility as predicted by the Diversity-invasibility hypothesis (DIH); (B) disturbed or anthropogenically influenced habitats are more sensitive for invasions than natural and undisturbed habitats; and (C) climatic differences between laurel forest sites do not affect the rate of invasibility. A large proportion of invasives (species and abundances) was observed in most of the studied arthropod groups. However, we did not find any support for the DIH based on the examined arthropod groups. Regarding the impact of the extrinsic factors 'disturbance' and 'climate' on invasion patterns, we found considerable differences between the studied functional groups. Whereas the 'disturbance parameters' played a minor role and only affected the relative abundances of invasive centipedes (positively) and millipedes (negatively), the 'climate parameters' were significantly linked with the pattern of invasive detritivores. Interactions between native and invading species have not been observed thus far, but cannot completely be excluded.

  8. The Effects of Copper Pollution on Fouling Assemblage Diversity: A Tropical-Temperate Comparison

    PubMed Central

    Canning-Clode, João; Fofonoff, Paul; Riedel, Gerhardt F.; Torchin, Mark; Ruiz, Gregory M.

    2011-01-01

    Background The invasion of habitats by non-indigenous species (NIS) occurs at a global scale and can generate significant ecological, evolutionary, economic and social consequences. Estuarine and coastal ecosystems are particularly vulnerable to pollution from numerous sources due to years of human-induced degradation and shipping. Pollution is considered as a class of disturbance with anthropogenic roots and recent studies have concluded that high frequencies of disturbance may facilitate invasions by increasing the availability of resources. Methodology/Principal Findings To examine the effects of heavy metal pollution as disturbance in shaping patterns of exotic versus native diversity in marine fouling communities we exposed fouling communities to different concentrations of copper in one temperate (Virginia) and one tropical (Panama) region. Diversity was categorized as total, native and non-indigenous and we also incorporated taxonomic and functional richness. Our findings indicate that total fouling diversity decreased with increasing copper pollution, whether taxonomic or functional diversity is considered. Both native and non-indigenous richness decreased with increasing copper concentrations at the tropical site whereas at the temperate site, non-indigenous richness was too low to detect any effect. Conclusions/Significance Non-indigenous richness decreased with increasing metal concentrations, contradicting previous investigations that evaluate the influence of heavy metal pollution on diversity and invasibility of fouling assemblages. These results provide first insights on how the invasive species pool in a certain region may play a key role in the disturbance vs. non-indigenous diversity relationship. PMID:21437262

  9. The role of viruses in biological invasions: friend or foe?

    PubMed

    Rúa, Megan A; Pollina, Emily C; Power, Alison G; Mitchell, Charles E

    2011-07-01

    Biological invasions occur when plants, animals, or microbes are introduced to a new geographic region, then spread and have negative consequences for the local ecosystem. Across both plant and animal hosts, viruses can play diverse roles in biological invasions. First, viruses can either decrease or increase the impacts of biological invasions by their hosts. Introduced hosts commonly leave behind many viruses from their native ranges, which may allow the hosts to achieve greater fitness and thus dominate in their introduced ranges. Viruses that do infect introduced hosts may reduce invasive host fitness and impacts. However, many viruses that infect introduced hosts also infect native hosts and may have more severe impacts on the native hosts. Second, viruses can also be invasive species themselves. While many viruses are believed to be introduced, it is challenging to differentiate between those that are native and those that are not. Third, many viruses are transmitted by vectors, which can also be introduced to new regions. Introduced vectors can increase virus transmission rates, altering host communities and ecosystems. Further advancing our understanding of the role of viruses in biological invasions will require research that integrates the systematics, biogeography and ecological history of hosts, vectors, and viruses.

  10. Comparison of genetic diversity of the invasive weed Rubus alceifolius poir. (Rosaceae) in its native range and in areas of introduction, using amplified fragment length polymorphism (AFLP) markers.

    PubMed

    Amsellem, L; Noyer, J L; Le Bourgeois, T; Hossaert-McKey, M

    2000-04-01

    Theory predicts that colonization of new areas will be associated with population bottlenecks that reduce within-population genetic diversity and increase genetic differentiation among populations. This should be especially true for weedy plant species, which are often characterized by self-compatible breeding systems and vegetative propagation. To test this prediction, and to evaluate alternative scenarios for the history of introduction, the genetic diversity of Rubus alceifolius was studied with amplified fragment length polymorphism (AFLP) markers in its native range in southeast Asia and in several areas where this plant has been introduced and is now a serious weed (Indian Ocean islands, Australia). In its native range, R. alceifolius showed great genetic variability within populations and among geographically close populations (populations sampled ranging from northern Vietnam to Java). In Madagascar, genetic variability was somewhat lower than in its native range, but still considerable. Each population sampled in the other Indian Ocean islands (Mayotte, La Réunion, Mauritius) was characterized by a single different genotype of R. alceifolius for the markers studied, and closely related to individuals from Madagascar. Queensland populations also included only a single genotype, identical to that found in Mauritius. These results suggest that R. alceifolius was first introduced into Madagascar, perhaps on multiple occasions, and that Madagascan individuals were the immediate source of plants that colonized other areas of introduction. Successive nested founder events appear to have resulted in cumulative reduction in genetic diversity. Possible explanations for the monoclonality of R. alceifolius in many areas of introduction are discussed.

  11. Species richness and interacting factors control invasibility of a marine community.

    PubMed

    Marraffini, M L; Geller, J B

    2015-08-01

    Anthropogenic vectors have moved marine species around the world leading to increased invasions and expanded species' ranges. The biotic resistance hypothesis of Elton (in The ecology of invasions by animals and plants, 1958) predicts that more diverse communities should have greater resistance to invasions, but experiments have been equivocal. We hypothesized that species richness interacts with other factors to determine experimental outcomes. We manipulated species richness, species composition (native and introduced) and availability of bare space in invertebrate assemblages in a marina in Monterey, CA. Increased species richness significantly interacted with both initial cover of native species and of all organisms to collectively decrease recruitment. Although native species decreased recruitment, introduced species had a similar effect, and we concluded that biotic resistance is conferred by total species richness. We suggest that contradictory conclusions in previous studies about the role of diversity in regulating invasions reflect uncontrolled variables in those experiments that modified the effect of species richness. Our results suggest that patches of low diversity and abundance may facilitate invasions, and that such patches, once colonized by non-indigenous species, can resist both native and non-indigenous species recruitment.

  12. Species richness and interacting factors control invasibility of a marine community

    PubMed Central

    Marraffini, M. L.; Geller, J. B.

    2015-01-01

    Anthropogenic vectors have moved marine species around the world leading to increased invasions and expanded species' ranges. The biotic resistance hypothesis of Elton (in The ecology of invasions by animals and plants, 1958) predicts that more diverse communities should have greater resistance to invasions, but experiments have been equivocal. We hypothesized that species richness interacts with other factors to determine experimental outcomes. We manipulated species richness, species composition (native and introduced) and availability of bare space in invertebrate assemblages in a marina in Monterey, CA. Increased species richness significantly interacted with both initial cover of native species and of all organisms to collectively decrease recruitment. Although native species decreased recruitment, introduced species had a similar effect, and we concluded that biotic resistance is conferred by total species richness. We suggest that contradictory conclusions in previous studies about the role of diversity in regulating invasions reflect uncontrolled variables in those experiments that modified the effect of species richness. Our results suggest that patches of low diversity and abundance may facilitate invasions, and that such patches, once colonized by non-indigenous species, can resist both native and non-indigenous species recruitment. PMID:26203005

  13. Radiotherapy Can Decrease Locoregional Recurrence and Increase Survival in Mastectomy Patients With T1 to T2 Breast Cancer and One to Three Positive Nodes With Negative Estrogen Receptor and Positive Lymphovascular Invasion Status

    SciTech Connect

    Yang, P.S.; Chen, C.M.; Liu, M.C.; Jian, J.M.; Horng, C.F.; Liu, M.J.; Yu, B.L.; Lee, M.Y.; Chi, C.W.

    2010-06-01

    Purpose: To define a subgroup of patients at high risk of locoregional recurrence (LRR) who might be benefit from postmastectomy radiotherapy in invasive breast cancer and tumor size <5 cm with one to three involved axillary lymph nodes (T1-2 N1). Methods and Materials: Between April 1991 and December 2005, 544 patients with T1-2 N1 invasive breast cancer were treated with modified radical mastectomy. Of the 544 patients, 383 patients (70.4%) had no radiotherapy, and 161 patients (29.6%) received radiotherapy. We retrospectively compared these two patient groups. Results: With a median follow-up of 40.3 months, LRR occurred in 40 (7.4%) of 544 patients. On univariate analysis, high nuclear grade (p = 0.04), negative estrogen receptor (ER) status (p = 0.001), presence of lymphovascular invasion (LVI) (p = 0.003), and no radiotherapy (p = 0.0015) were associated with a significantly higher rate of LRR. Negative ER status (hazard ratio = 5.1) and presence of LVI (hazard ratio = 2.5) were the risk factors for LRR with statistical significance in the multivariate analysis. Radiotherapy reduced the LRR in patients with the following characteristics: age <40 years, T2 stage, high nuclear grade, negative ER status, and presence of LVI. For 41 patients with negative ER and positive LVI status, radiotherapy can reduce LRR from 10 of 25 (40%) to 2 of 16 (12.5%) and increase the 5-year overall survival from 43.7% to 87.1%. Conclusion: Radiotherapy can reduce LRR and increase survival in T1-2 N1 breast cancer patients with negative ER status and presence of LVI.

  14. Genetic Diversity of the Invasive Gall Wasp Leptocybe invasa (Hymenoptera: Eulophidae) and of its Rickettsia Endosymbiont, and Associated Sex-Ratio Differences.

    PubMed

    Nugnes, Francesco; Gebiola, Marco; Monti, Maurilia Maria; Gualtieri, Liberata; Giorgini, Massimo; Wang, Jianguo; Bernardo, Umberto

    2015-01-01

    The blue-gum chalcid Leptocybe invasa Fisher & LaSalle (Hymenoptera: Eulophidae) is a gall wasp pest of Eucalyptus species, likely native to Australia. Over the past 15 years it has invaded 39 countries on all continents where eucalypts are grown. The worldwide invasion of the blue gum chalcid was attributed to a single thelytokous morphospecies formally described in 2004. Subsequently, however, males have been recorded in several countries and the sex ratio of field populations has been found to be highly variable in different areas. In order to find an explanation for such sex ratio differences, populations of L. invasa from a broad geographical area were screened for the symbionts currently known as reproductive manipulators, and both wasps and symbionts were genetically characterized using multiple genes. Molecular analyses suggested that L. invasa is in fact a complex of two cryptic species involved in the rapid and efficient spread of the wasp, the first recovered from the Mediterranean region and South America, the latter from China. All screened specimens were infected by endosymbiotic bacteria belonging to the genus Rickettsia. Two closely related Rickettsia strains were found, each infecting one of the two putative cryptic species of L. invasa and associated with different average sex ratios. Rickettsia were found to be localized in the female reproductive tissues and transovarially transmitted, suggesting a possible role of Rickettsia as the causal agent of thelytokous parthenogenesis in L. invasa. Implications for the variation of sex ratio and for the management of L. invasa are discussed.

  15. Overview of worldwide diversity of Diaphorina citri Kuwayama mitochondrial cytochrome oxidase 1 haplotypes: two Old World lineages and a New World invasion.

    PubMed

    Boykin, L M; De Barro, P; Hall, D G; Hunter, W B; McKenzie, C L; Powell, C A; Shatters, R G

    2012-10-01

    Relationships among worldwide collections of Diaphorina citri (Asian citrus psyllid) were analyzed using mitochondrial cytochrome oxidase I (mtCOI) haplotypes from novel primers. Sequences were produced from PCR amplicons of an 821bp portion of the mtCOI gene using D. citri specific primers, derived from an existing EST library. An alignment was constructed using 612bps of this fragment and consisted of 212 individuals from 52 collections representing 15 countries. There were a total of eight polymorphic sites that separated the sequences into eight different haplotypes (Dcit-1 through Dcit-8). Phylogenetic network analysis using the statistical parsimony software, TCS, suggests two major haplotype groups with preliminary geographic bias between southwestern Asia (SWA) and southeastern Asia (SEA). The recent (within the last 15 to 25 years) invasion into the New World originated from only the SWA group in the northern hemisphere (USA and Mexico) and from both the SEA and SWA groups in the southern hemisphere (Brazil). In only one case, Reunion Island, did haplotypes from both the SEA and SWA group appear in the same location. In Brazil, both groups were present, but in separate locations. The Dcit-1 SWA haplotype was the most frequently encountered, including ~50% of the countries sampled and 87% of the total sequences obtained from India, Pakistan and Saudi Arabia. The second most frequently encountered haplotype, Dcit-2, the basis of the SEA group, represented ~50% of the countries and contained most of the sequences from Southeast Asia and China. Interestingly, only the Caribbean collections (Puerto Rico and Guadeloupe) represented a unique haplotype not found in other countries, indicating no relationship between the USA (Florida) and Caribbean introductions. There is no evidence for cryptic speciation for D. citri based on the COI region included in this study.

  16. Overview of worldwide diversity of Diaphorina citri Kuwayama mitochondrial cytochrome oxidase 1 haplotypes: two Old World lineages and a New World invasion

    PubMed Central

    Boykin, L.M.; De Barro, P.; Hall, D.G.; Hunter, W.B.; McKenzie, C.L.; Powell, C.A.; Shatters, R.G.

    2012-01-01

    Relationships among worldwide collections of Diaphorina citri (Asian citrus psyllid) were analyzed using mitochondrial cytochrome oxidase I (mtCOI) haplotypes from novel primers. Sequences were produced from PCR amplicons of an 821bp portion of the mtCOI gene using D. citri specific primers, derived from an existing EST library. An alignment was constructed using 612bps of this fragment and consisted of 212 individuals from 52 collections representing 15 countries. There were a total of eight polymorphic sites that separated the sequences into eight different haplotypes (Dcit-1 through Dcit-8). Phylogenetic network analysis using the statistical parsimony software, TCS, suggests two major haplotype groups with preliminary geographic bias between southwestern Asia (SWA) and southeastern Asia (SEA). The recent (within the last 15 to 25 years) invasion into the New World originated from only the SWA group in the northern hemisphere (USA and Mexico) and from both the SEA and SWA groups in the southern hemisphere (Brazil). In only one case, Reunion Island, did haplotypes from both the SEA and SWA group appear in the same location. In Brazil, both groups were present, but in separate locations. The Dcit-1 SWA haplotype was the most frequently encountered, including ~50% of the countries sampled and 87% of the total sequences obtained from India, Pakistan and Saudi Arabia. The second most frequently encountered haplotype, Dcit-2, the basis of the SEA group, represented ~50% of the countries and contained most of the sequences from Southeast Asia and China. Interestingly, only the Caribbean collections (Puerto Rico and Guadeloupe) represented a unique haplotype not found in other countries, indicating no relationship between the USA (Florida) and Caribbean introductions. There is no evidence for cryptic speciation for D. citri based on the COI region included in this study. PMID:22717059

  17. Resolving the genetic basis of invasiveness and predicting invasions.

    PubMed

    Weinig, Cynthia; Brock, Marcus T; Dechaine, Jenny A; Welch, Stephen M

    2007-02-01

    Considerable effort has been invested in determining traits underlying invasiveness. Yet, identifying a set of traits that commonly confers invasiveness in a range of species has proven elusive, and almost nothing is known about genetic loci affecting invasive success. Incorporating genetic model organisms into ecologically relevant studies is one promising avenue to begin dissecting the genetic underpinnings of invasiveness. Molecular biologists are rapidly characterizing genes mediating developmental responses to diverse environmental cues, i.e., genes for plasticity, as well as to environmental factors likely to impose strong selection on invading species, e.g., resistance to herbivores and competitors, coordination of life-history events with seasonal changes, and physiological tolerance of heat, drought, or cold. Here, we give an overview of molecular genetic tools increasingly used to characterize the genetic basis of adaptation and that may be used to begin identifying genetic mechanisms of invasiveness. Given the divergent traits that affect invasiveness, "invasiveness genes" common to many clades are unlikely, but the combination of developmental genetic advances with further evolutionary studies and modeling may provide a framework for identifying genes that account for invasiveness in related species.

  18. Genetic reconstructions of invasion history.

    PubMed

    Cristescu, Melania E

    2015-05-01

    A diverse array of molecular markers and constantly evolving analytical approaches have been employed to reconstruct the invasion histories of the most notorious invasions. Detailed information on the source(s) of introduction, invasion route, type of vectors, number of independent introductions and pathways of secondary spread has been corroborated for a large number of biological invasions. In this review, I present the promises and limitations of current techniques while discussing future directions. Broad phylogeographic surveys of native and introduced populations have traced back invasion routes with surprising precision. These approaches often further clarify species boundaries and reveal complex patterns of genetic relationships with noninvasive relatives. Moreover, fine-scale analyses of population genetics or genomics allow deep inferences on the colonization dynamics across invaded ranges and can reveal the extent of gene flow among populations across various geographical scales, major demographic events such as genetic bottlenecks as well as other important evolutionary events such as hybridization with native taxa, inbreeding and selective sweeps. Genetic data have been often corroborated successfully with historical, geographical and ecological data to enable a comprehensive reconstruction of the invasion process. The advent of next-generation sequencing, along with the availability of extensive databases of repository sequences generated by barcoding projects opens the opportunity to broadly monitor biodiversity, to identify early invasions and to quantify failed invasions that would otherwise remain inconspicuous to the human eye. PMID:25703061

  19. Invasive arthropods.

    PubMed

    Sanders, C J; Mellor, P S; Wilson, A J

    2010-08-01

    Many arthropod species have been transported around the globe and successfully invaded new regions. Invasive arthropods can have severe impacts on animal and human health, agriculture and forestry, and the biodiversity of natural habitats as well as those modified by humans. The economic and environmental effects of invasion can be both direct, through feeding and competition, and indirect, such as the transmission of pathogens. In this paper, the authors consider ten examples that illustrate the main mechanisms of introduction, the characteristics that enable species to rapidly expand their ranges and some of the consequences of their arrival.

  20. Development of dual PLD1/2 and PLD2 selective inhibitors from a common 1,3,8-Triazaspiro[4.5]decane Core: discovery of Ml298 and Ml299 that decrease invasive migration in U87-MG glioblastoma cells.

    PubMed

    O'Reilly, Matthew C; Scott, Sarah A; Brown, Kyle A; Oguin, Thomas H; Thomas, Paul G; Daniels, J Scott; Morrison, Ryan; Brown, H Alex; Lindsley, Craig W

    2013-03-28

    An iterative parallel synthesis effort identified a PLD2 selective inhibitor, ML298 (PLD1 IC50 > 20000 nM, PLD2 IC50 = 355 nM) and a dual PLD1/2 inhibitor, ML299 (PLD1 IC50 = 6 nM, PLD2 IC50 = 20 nM). SAR studies revealed that a small structural change (incorporation of a methyl group) increased PLD1 activity within this classically PLD2-preferring core and that the effect was enantiospecific. Both probes decreased invasive migration in U87-MG glioblastoma cells.

  1. INVASIVE PLANTS HARBOR HUNGRY DETRITIVORES THAT ALTER ECOSYSTEM FUNCTION

    EPA Science Inventory

    Ecosystems are expected to function more efficiently in response to a diverse community of inhabitants. However, biological invasions may change expected relationships between ecosystem function and diversity. We observed increased decomposition, a measure of ecosystem function...

  2. Global ecological impacts of invasive species in aquatic ecosystems.

    PubMed

    Gallardo, Belinda; Clavero, Miguel; Sánchez, Marta I; Vilà, Montserrat

    2016-01-01

    The introduction of invasive species, which often differ functionally from the components of the recipient community, generates ecological impacts that propagate along the food web. This review aims to determine how consistent the impacts of aquatic invasions are across taxa and habitats. To that end, we present a global meta-analysis from 151 publications (733 cases), covering a wide range of invaders (primary producers, filter collectors, omnivores and predators), resident aquatic community components (macrophytes, phytoplankton, zooplankton, benthic invertebrates and fish) and habitats (rivers, lakes and estuaries). Our synthesis suggests a strong negative influence of invasive species on the abundance of aquatic communities, particularly macrophytes, zooplankton and fish. In contrast, there was no general evidence for a decrease in species diversity in invaded habitats, suggesting a time lag between rapid abundance changes and local extinctions. Invaded habitats showed increased water turbidity, nitrogen and organic matter concentration, which are related to the capacity of invaders to transform habitats and increase eutrophication. The expansion of invasive macrophytes caused the largest decrease in fish abundance, the filtering activity of filter collectors depleted planktonic communities, omnivores (including both facultative and obligate herbivores) were responsible for the greatest decline in macrophyte abundance, and benthic invertebrates were most negatively affected by the introduction of new predators. These impacts were relatively consistent across habitats and experimental approaches. Based on our results, we propose a framework of positive and negative links between invasive species at four trophic positions and the five different components of recipient communities. This framework incorporates both direct biotic interactions (predation, competition, grazing) and indirect changes to the water physicochemical conditions mediated by invaders (habitat

  3. Global ecological impacts of invasive species in aquatic ecosystems.

    PubMed

    Gallardo, Belinda; Clavero, Miguel; Sánchez, Marta I; Vilà, Montserrat

    2016-01-01

    The introduction of invasive species, which often differ functionally from the components of the recipient community, generates ecological impacts that propagate along the food web. This review aims to determine how consistent the impacts of aquatic invasions are across taxa and habitats. To that end, we present a global meta-analysis from 151 publications (733 cases), covering a wide range of invaders (primary producers, filter collectors, omnivores and predators), resident aquatic community components (macrophytes, phytoplankton, zooplankton, benthic invertebrates and fish) and habitats (rivers, lakes and estuaries). Our synthesis suggests a strong negative influence of invasive species on the abundance of aquatic communities, particularly macrophytes, zooplankton and fish. In contrast, there was no general evidence for a decrease in species diversity in invaded habitats, suggesting a time lag between rapid abundance changes and local extinctions. Invaded habitats showed increased water turbidity, nitrogen and organic matter concentration, which are related to the capacity of invaders to transform habitats and increase eutrophication. The expansion of invasive macrophytes caused the largest decrease in fish abundance, the filtering activity of filter collectors depleted planktonic communities, omnivores (including both facultative and obligate herbivores) were responsible for the greatest decline in macrophyte abundance, and benthic invertebrates were most negatively affected by the introduction of new predators. These impacts were relatively consistent across habitats and experimental approaches. Based on our results, we propose a framework of positive and negative links between invasive species at four trophic positions and the five different components of recipient communities. This framework incorporates both direct biotic interactions (predation, competition, grazing) and indirect changes to the water physicochemical conditions mediated by invaders (habitat

  4. Giant invasive prolactinomas

    SciTech Connect

    Murphy, F.Y.; Vesely, D.L.; Jordan, R.M.; Flanigan, S.; Kohler, P.O.

    1987-11-01

    Two of the largest prolactinomas ever documented that have been followed for nine and 10 years, respectively, demonstrate how aggressive prolactinomas may become and how difficult invasive prolactinomas are to treat. One of these prolactinomas invaded both internal auditory canals and simultaneously grew inferiorly, reducing the bony support of the skull and necessitating the patient to utilize both hands to hold his head up. The second patient's prolactinoma invaded the sphenoidal, ethmoidal, and cavernous sinuses. Both of these patients had neurosurgical debulking of their tumors followed by radiation therapy. Neither patient's prolactin levels decreased significantly during their first five years post-surgically, at which time bromocriptine was added. Since then, there has been a gradual lowering of serum prolactin levels and a decrease in the size of these tumors. These cases demonstrate that prolonged treatment and very large doses of bromocriptine may be necessary for tumor reduction in patients with invasive prolactinomas.

  5. Coevolution between native and invasive plant competitors: implications for invasive species management.

    PubMed

    Leger, Elizabeth A; Espeland, Erin K

    2010-03-01

    Invasive species may establish in communities because they are better competitors than natives, but in order to remain community dominants, the competitive advantage of invasive species must be persistent. Native species that are not extirpated when highly invasive species are introduced are likely to compete with invaders. When population sizes and genetic diversity of native species are large enough, natives may be able to evolve traits that allow them to co-occur with invasive species. Native species may also evolve to become significant competitors with invasive species, and thus affect the fitness of invaders. Invasive species may respond in turn, creating either transient or continuing coevolution between competing species. In addition to demographic factors such as population size and growth rates, a number of factors including gene flow, genetic drift, the number of selection agents, encounter rates, and genetic diversity may affect the ability of native and invasive species to evolve competitive ability against one another. We discuss how these factors may differ between populations of native and invasive plants, and how this might affect their ability to respond to selection. Management actions that maintain genetic diversity in native species while reducing population sizes and genetic diversity in invasive species could promote the ability of natives to evolve improved competitive ability.

  6. Eco-immunology of fish invasions: the role of MHC variation.

    PubMed

    Monzón-Argüello, C; Garcia de Leaniz, C; Gajardo, G; Consuegra, S

    2014-06-01

    The relationship between invaders and the pathogens encountered in their new environment can have a large effect on invasion success. Invaders can become free from their natural pathogens and reallocate costly immune resources to growth and reproduction, thereby increasing invasion success. Release from enemies and relaxation of selective pressures could render newly founded populations more variable at immune-related genes, such as the major histocompatibility complex (MHC), particularly when they have different origins. Using rainbow and brown trout, two of the world's most successful fish invaders, we tested the general hypothesis that invaders should display high intrapopulation immunogenetic diversity and interpopulation divergence, due to the interplay between genetic drift and successive waves of genetically divergent introductions. We analysed genetic diversity and signatures of selection at the MHC class II β immune-related locus. In both species, MHC diversity (allelic richness and heterozygosity) for southern hemisphere populations was similar to values reported for populations at their native range. However, MHC functional diversity was limited, and population immunogenetic structuring weaker than that observed using neutral markers. Depleted MHC functional diversity could reflect a decrease in immune response, immune-related assortative mating or selection for resistance to newly encountered parasites. Given that the role of MHC diversity in the survival of these populations remains unclear, depleted functional diversity of invasive salmonids could compromise their long-term persistence. A better understanding of the eco-immunology of invaders may help in managing and preventing the impact of biological invasions, a major cause of loss of biodiversity worldwide.

  7. Negative effects of an exotic grass invasion on small-mammal communities.

    PubMed

    Freeman, Eric D; Sharp, Tiffanny R; Larsen, Randy T; Knight, Robert N; Slater, Steven J; McMillan, Brock R

    2014-01-01

    Exotic invasive species can directly and indirectly influence natural ecological communities. Cheatgrass (Bromus tectorum) is non-native to the western United States and has invaded large areas of the Great Basin. Changes to the structure and composition of plant communities invaded by cheatgrass likely have effects at higher trophic levels. As a keystone guild in North American deserts, granivorous small mammals drive and maintain plant diversity. Our objective was to assess potential effects of invasion by cheatgrass on small-mammal communities. We sampled small-mammal and plant communities at 70 sites (Great Basin, Utah). We assessed abundance and diversity of the small-mammal community, diversity of the plant community, and the percentage of cheatgrass cover and shrub species. Abundance and diversity of the small-mammal community decreased with increasing abundance of cheatgrass. Similarly, cover of cheatgrass remained a significant predictor of small-mammal abundance even after accounting for the loss of the shrub layer and plant diversity, suggesting that there are direct and indirect effects of cheatgrass. The change in the small-mammal communities associated with invasion of cheatgrass likely has effects through higher and lower trophic levels and has the potential to cause major changes in ecosystem structure and function.

  8. Short-term parasite-infection alters already the biomass, activity and functional diversity of soil microbial communities

    NASA Astrophysics Data System (ADS)

    Li, Jun-Min; Jin, Ze-Xin; Hagedorn, Frank; Li, Mai-He

    2014-11-01

    Native parasitic plants may be used to infect and control invasive plants. We established microcosms with invasive Mikania micrantha and native Coix lacryma-jobi growing in mixture on native soils, with M. micrantha being infected by parasitic Cuscuta campestris at four intensity levels for seven weeks to estimate the top-down effects of plant parasitism on the biomass and functional diversity of soil microbial communities. Parasitism significantly decreased root biomass and altered soil microbial communities. Soil microbial biomass decreased, but soil respiration increased at the two higher infection levels, indicating a strong stimulation of soil microbial metabolic activity (+180%). Moreover, a Biolog assay showed that the infection resulted in a significant change in the functional diversity indices of soil microbial communities. Pearson correlation analysis indicated that microbial biomass declined significantly with decreasing root biomass, particularly of the invasive M. micrantha. Also, the functional diversity indices of soil microbial communities were positively correlated with soil microbial biomass. Therefore, the negative effects on the biomass, activity and functional diversity of soil microbial community by the seven week long plant parasitism was very likely caused by decreased root biomass and root exudation of the invasive M. micrantha.

  9. [Emerging invasive fungal infections].

    PubMed

    Alvez, F; Figueras, C; Roselló, E

    2010-07-01

    The frequency and diversity of invasive fungal infections has changed over the last 25 years. The emergence of less common, but medically important fungi has increased, and the children at risk has expanded, with the inclusion of medical conditions such as cancer, mainly haematological malignancy or stem cell transplant, immunosuppressive therapy, prolonged neutropenia, and T-cell immunodeficiency. Among mould infections, fusariosis and phaeohyphomycosis (Dematiaceous fungi) have been increasingly reported in this group of patients. To successfully manage these challenging infections, it is imperative that paediatricians and sub-specialists remain aware of the optimal and timely diagnosis and therapeutic options. Unlike other common mycoses that cause human disease, there no simple antigen or serological tests available to detect these pathogens in tissue or blood. The outcome for these disseminate, and often refractory fungal infections in neutropenic patients and transplant recipients remains extremely poor, requiring early and aggressive therapy. Unfortunately there are no guidelines outlining the choices for optimal therapy in the treatment of paediatric invasive fungal infections do not exist, and on the other hand are limited paediatric data available comparing antifungal agents in children with proven, probable or suspected invasive fungal infection. The options for treatment rest mainly on some adult guidelines that comment on the treatment of these emerging and uncommon important fungi in children. Despite the sparse clinical trials available on treatment and its poor outcome, options for treatment of invasive fungal infections have increased with the advance of new antifungal agents, with improved tolerability and increased range of activity. The epidemiology, clinical manifestations, diagnosis and treatment of fusariosis and phaeohyphomycosis are discussed in this article.

  10. Eukaryotic Cell Invasion does not correlate to flaA SVR Sequence Type based on a Library of Genetically Diverse Campylobacter jejuni Isolates Originally Recovered from A Variety of Sources in Iceland

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Introduction: Campylobacter spp. are considered to be a leading bacterial etiologic agent of acute food-borne gastroenteritis among human populations. Epithelial cell invasion is hypothesized to be necessary for human infection and cell invasion assays have been utilized to demonstrate that distinc...

  11. PCR-Based Quantitation and Clonal Diversity of the Current Prevalent Invasive Serogroup 6 Pneumococcal Serotype, 6C, in the United States in 1999 and 2006 to 2007▿

    PubMed Central

    da Gloria Carvalho, Maria; Pimenta, Fabiana C.; Gertz, Robert E.; Joshi, Hari Har; Trujillo, Alma A.; Keys, Logan E.; Findley, Joy; Moura, Iaci S.; Park, In H.; Hollingshead, Susan K.; Pilishvili, Tamara; Whitney, Cynthia G.; Nahm, Moon H.; Beall, Bernard W.

    2009-01-01

    Following introduction of the 7-valent pneumococcal conjugate vaccine to the United States, rates of invasive pneumococcal disease (IPD) caused by serotype 6A declined among all age groups, while rates of IPD caused by newly identified serotype 6C increased slightly among persons 5 years of age and older. Conventionally serotyped 6A isolates (CS6As) from active population-based surveillance during 1999 and 2006 to 2007 were classified as serotypes 6A and 6C by an expedient and highly accurate serotype 6C-specific PCR assay developed during this study. PCR testing of 636 year 1999, 2006, and 2007 CS6As revealed 6C proportions of 35/214 (16.4%), 141/218 (64.7%), and 141/204 (69.1%), respectively. These results agreed with those from a previously devised monoclonal antibody-based serotyping system (346 CS6As compared). Type 6C IPD incidence significantly increased during 2006 and 2007 compared to during 1999 (0.57 to 0.58 cases per 100,000 and 0.22 cases per 100,000, respectively; 164% increase from 1999 to 2007 [95% confidence interval, 87 to 270%]), while rates of IPD due to types 6A and 6B markedly decreased. In 2007, 31.2% of 6C isolates were not susceptible to penicillin. Serotype 6C is now the predominant serotype associated with serogroup 6 IPD in the United States and is often penicillin nonsusceptible. We performed multilocus sequence typing (MLST) on a limited sampling of 6C isolates with different antimicrobial susceptibility profiles. MLST of 42 6C isolates revealed 12 genotypes distributed among six distinct genetic groups. Fifteen 6C isolates shared one of four different MLST types with 6C-negative CS6As. MLST results suggest 6C strains arose from independent recombination events involving only serotype 6A and 6C parental strains. PMID:19116353

  12. Esophagectomy - minimally invasive

    MedlinePlus

    Minimally invasive esophagectomy; Robotic esophagectomy; Removal of the esophagus - minimally invasive; Achalasia - esophagectomy; Barrett esophagus - esophagectomy; Esophageal cancer - esophagectomy - laparoscopic; Cancer of the ...

  13. [Micro-invasive glaucoma surgery].

    PubMed

    Achiron, Asaf; Sharif, Nardeen; Achiron, Romi Noy; Nisimov, Sagee; Burgansky-Eliash, Sagee

    2014-10-01

    Intraocular pressure (IOP) reduction is the current treatment in glaucoma. In recent years, minimally invasive glaucoma surgery (MIGS) has been added to the arsenal of surgical options. MIGS can reduce trabecular meshwork resistance to outflow and decrease the IOP with mild side effects. In this article, we review the clinical experience gathered with iSTENT, Bypass, Gold Micro Shunt and the Trabectome.

  14. Minimally Invasive Cardiovascular Surgery: Incisions and Approaches

    PubMed Central

    Langer, Nathaniel B.; Argenziano, Michael

    2016-01-01

    Throughout the modern era of cardiac surgery, most operations have been performed via median sternotomy with cardiopulmonary bypass. This paradigm is changing, however, as cardiovascular surgery is increasingly adopting minimally invasive techniques. Advances in patient evaluation, instrumentation, and operative technique have allowed surgeons to perform a wide variety of complex operations through smaller incisions and, in some cases, without cardiopulmonary bypass. With patients desiring less invasive operations and the literature supporting decreased blood loss, shorter hospital length of stay, improved postoperative pain, and better cosmesis, minimally invasive cardiac surgery should be widely practiced. Here, we review the incisions and approaches currently used in minimally invasive cardiovascular surgery. PMID:27127555

  15. [Invasive yeast infections in neutropenic patients].

    PubMed

    Ruiz Camps, Isabel; Jarque, Isidro

    2016-01-01

    Invasive fungal diseases caused by yeasts still play an important role in the morbidity and mortality in neutropenic patients with haematological malignancies. Although the overall incidence of invasive candidiasis has decreased due to widespread use of antifungal prophylaxis, the incidence of non-Candida albicans Candida species is increasing compared with that of C.albicans, and mortality of invasive candidiasis continues to be high. In addition, there has been an increase in invasive infections caused by an array of uncommon yeasts, including species of the genus Malassezia, Rhodotorula, Trichosporon and Saprochaete, characterised by their resistance to echinocandins and poor prognosis.

  16. Diverse Thinking about Diversity

    ERIC Educational Resources Information Center

    Kaplan, Sandra N.

    2013-01-01

    This article focuses on the concept of diversity in educational decision making. It is noted that the differences that distinguish the needs, interests and abilities are identified by educators. It lists misconceptions resulting from not attending to within-group diversity, and states that a "loss of self" for individual members of…

  17. Climate-driven diversity loss in a grassland community.

    PubMed

    Harrison, Susan P; Gornish, Elise S; Copeland, Stella

    2015-07-14

    Local ecological communities represent the scale at which species coexist and share resources, and at which diversity has been experimentally shown to underlie stability, productivity, invasion resistance, and other desirable community properties. Globally, community diversity shows a mixture of increases and decreases over recent decades, and these changes have relatively seldom been linked to climatic trends. In a heterogeneous California grassland, we documented declining plant diversity from 2000 to 2014 at both the local community (5 m(2)) and landscape (27 km(2)) scales, across multiple functional groups and soil environments. Communities became particularly poorer in native annual forbs, which are present as small seedlings in midwinter; within native annual forbs, community composition changed toward lower representation of species with a trait indicating drought intolerance (high specific leaf area). Time series models linked diversity decline to the significant decrease in midwinter precipitation. Livestock grazing history, fire, succession, N deposition, and increases in exotic species could be ruled out as contributing causes. This finding is among the first demonstrations to our knowledge of climate-driven directional loss of species diversity in ecological communities in a natural (nonexperimental) setting. Such diversity losses, which may also foreshadow larger-scale extinctions, may be especially likely in semiarid regions that are undergoing climatic trends toward higher aridity and lower productivity. PMID:26100891

  18. Climate-driven diversity loss in a grassland community.

    PubMed

    Harrison, Susan P; Gornish, Elise S; Copeland, Stella

    2015-07-14

    Local ecological communities represent the scale at which species coexist and share resources, and at which diversity has been experimentally shown to underlie stability, productivity, invasion resistance, and other desirable community properties. Globally, community diversity shows a mixture of increases and decreases over recent decades, and these changes have relatively seldom been linked to climatic trends. In a heterogeneous California grassland, we documented declining plant diversity from 2000 to 2014 at both the local community (5 m(2)) and landscape (27 km(2)) scales, across multiple functional groups and soil environments. Communities became particularly poorer in native annual forbs, which are present as small seedlings in midwinter; within native annual forbs, community composition changed toward lower representation of species with a trait indicating drought intolerance (high specific leaf area). Time series models linked diversity decline to the significant decrease in midwinter precipitation. Livestock grazing history, fire, succession, N deposition, and increases in exotic species could be ruled out as contributing causes. This finding is among the first demonstrations to our knowledge of climate-driven directional loss of species diversity in ecological communities in a natural (nonexperimental) setting. Such diversity losses, which may also foreshadow larger-scale extinctions, may be especially likely in semiarid regions that are undergoing climatic trends toward higher aridity and lower productivity.

  19. Understanding invasion history and predicting invasive niches using genetic sequencing technology in Australia: case studies from Cucurbitaceae and Boraginaceae

    PubMed Central

    Shaik, Razia S.; Zhu, Xiaocheng; Clements, David R.; Weston, Leslie A.

    2016-01-01

    Part of the challenge in dealing with invasive plant species is that they seldom represent a uniform, static entity. Often, an accurate understanding of the history of plant introduction and knowledge of the real levels of genetic diversity present in species and populations of importance is lacking. Currently, the role of genetic diversity in promoting the successful establishment of invasive plants is not well defined. Genetic profiling of invasive plants should enhance our understanding of the dynamics of colonization in the invaded range. Recent advances in DNA sequencing technology have greatly facilitated the rapid and complete assessment of plant population genetics. Here, we apply our current understanding of the genetics and ecophysiology of plant invasions to recent work on Australian plant invaders from the Cucurbitaceae and Boraginaceae. The Cucurbitaceae study showed that both prickly paddy melon (Cucumis myriocarpus) and camel melon (Citrullus lanatus) were represented by only a single genotype in Australia, implying that each was probably introduced as a single introduction event. In contrast, a third invasive melon, Citrullus colocynthis, possessed a moderate level of genetic diversity in Australia and was potentially introduced to the continent at least twice. The Boraginaceae study demonstrated the value of comparing two similar congeneric species; one, Echium plantagineum, is highly invasive and genetically diverse, whereas the other, Echium vulgare, exhibits less genetic diversity and occupies a more limited ecological niche. Sequence analysis provided precise identification of invasive plant species, as well as information on genetic diversity and phylogeographic history. Improved sequencing technologies will continue to allow greater resolution of genetic relationships among invasive plant populations, thereby potentially improving our ability to predict the impact of these relationships upon future spread and better manage invaders possessing

  20. Increased constituent ratios of Klebsiella sp., Acinetobacter sp., and Streptococcus sp. and a decrease in microflora diversity may be indicators of ventilator-associated pneumonia: a prospective study in the respiratory tracts of neonates.

    PubMed

    Lu, Wei; Yu, Jialin; Ai, Qing; Liu, Dong; Song, Chao; Li, Luquan

    2014-01-01

    Ventilator-associated pneumonia (VAP) is a common complication and cause of death in neonates on mechanical ventilation. However, it is difficult to define the causes of VAP. To understand the causes of VAP, we undertook a prospective study based on the diversity of the microflora in VAP. The experimental group consisted of newborns who suffered from respiratory distress syndrome (RDS) and VAP, while the control group suffered from RDS without VAP. Sputa were collected within 1, 3, and 5 days of ventilation and were divided into six groups. DNA was extracted from the samples, and the 16S rDNA was PCR amplified, separated using denaturing gradient gel electrophoresis (DGGE), cloned and sequenced. The resulting sequences were compared using BLAST. The DGGE pictures were measured, and the richness, Shannon-Wiener index, and cluster maps were analyzed. No differences were found regarding the constituent ratio of any genus between the Non-VAP and VAP group within 1 day after intubation. After 1 to 3 days, the constituent ratios of Klebsiella sp., Acinetobacter sp., and Streptococcus sp. in the VAP group were higher than those in the Non-VAP group, and the ratios of Serratia sp. and Achromobacter sp. were lower. After 3 to 5 days, the ratios of Klebsiella sp., Acinetobacter sp., Serratia sp., and Achromobacter sp. were lower than those in the Non-VAP group. The richness and Shannon-Wiener index of the Non-VAP group were higher than those of the VAP group from 1 to 3 days after intubation, while no differences were found within 1 day and from 3 to 5 days. We conclude that during the first three days of intubation, the microflora diversity in the lower respiratory tract was reduced due to VAP, and the greater constituent ratios of Klebsiella sp., Acinetobacter sp., and Streptococcus sp. in the sputum may be indicators of VAP.

  1. Minimally invasive parathyroid surgery

    PubMed Central

    Noureldine, Salem I.; Gooi, Zhen

    2015-01-01

    Traditionally, bilateral cervical exploration for localization of all four parathyroid glands and removal of any that are grossly enlarged has been the standard surgical treatment for primary hyperparathyroidism (PHPT). With the advances in preoperative localization studies and greater public demand for less invasive procedures, novel targeted, minimally invasive techniques to the parathyroid glands have been described and practiced over the past 2 decades. Minimally invasive parathyroidectomy (MIP) can be done either through the standard Kocher incision, a smaller midline incision, with video assistance (purely endoscopic and video-assisted techniques), or through an ectopically placed, extracervical, incision. In current practice, once PHPT is diagnosed, preoperative evaluation using high-resolution radiographic imaging to localize the offending parathyroid gland is essential if MIP is to be considered. The imaging study results suggest where the surgeon should begin the focused procedure and serve as a road map to allow tailoring of an efficient, imaging-guided dissection while eliminating the unnecessary dissection of multiple glands or a bilateral exploration. Intraoperative parathyroid hormone (IOPTH) levels may be measured during the procedure, or a gamma probe used during radioguided parathyroidectomy, to ascertain that the correct gland has been excised and that no other hyperfunctional tissue is present. MIP has many advantages over the traditional bilateral, four-gland exploration. MIP can be performed using local anesthesia, requires less operative time, results in fewer complications, and offers an improved cosmetic result and greater patient satisfaction. Additional advantages of MIP are earlier hospital discharge and decreased overall associated costs. This article aims to address the considerations for accomplishing MIP, including the role of preoperative imaging studies, intraoperative adjuncts, and surgical techniques. PMID:26425454

  2. Invasive Cervical Cancer and Antidepressants

    PubMed Central

    Chan, Hsiang-Lin; Hsieh, Yi-Hsuan; Lin, Chiao-Fan; Liang, Hsin-Yi; Huang, Kuo-You; Chiu, Wei-Che; Lee, Yena; McIntyre, Roger S.; Chen, Vincent Chin-Hung

    2015-01-01

    Abstract To our knowledge, no prior population-based study has been published wherein the primary aim was to evaluate whether an association between psychotropic drug prescription and cervical cancer exists. Herein we have conducted the first study that primarily aimed to determine the association between antidepressants use and risk of invasive cervical cancer in the general population. This is a population-based study utilizing Taiwan's National Health Insurance Research Database. We identified 26,262 cases with invasive cervical cancer and 129,490 controls. We adopted the conditional logistic regression model as the statistical method and adjusted for potential confounding factors. The prescription of selective serotonin reuptake inhibitors (SSRIs) (adjusted OR = 0.93, 95% CI = 0.84–1.04), tricyclic antidepressants (TCAs), monoamine oxidase inhibitors (MAOIs), serotonin norepinephrine reuptake inhibitors (SNRIs), mirtazapine and bupropion, adjusting for cumulative dose, was not associated with an increased, or decreased, risk for invasive cervical cancer. An association between trazodone prescription and invasive cervical cancer was observed (adjusted OR = 1.22, 95% CI = 1.03–1.43). An association between the major classes of antidepressants and invasive cervical cancer was not observed herein. Our preliminary finding regarding a possible association between trazodone and cervical cancer requires replication. PMID:26496343

  3. Microbial invasions: the process, patterns, and mechanisms.

    PubMed

    Mallon, Cyrus Alexander; Elsas, Jan Dirk van; Salles, Joana Falcão

    2015-11-01

    There has recently been a surge of literature examining microbial invasions into a variety of environments. These studies often include a component of biological diversity as a major factor determining an invader's fate, yet common results are rarely cross-compared. Since many studies only present a snapshot of the entire invasion process, a bird's eye view is required to piece together the entire continuum, which we find consists of introduction, establishment, spread, and impact phases. We further examine the patterns and mechanisms associated with invasion resistance and create a mechanistic synthesis governed by the species richness, species evenness, and resource availability of resident communities. We conclude by exploring the advantages of using a theoretical invasion framework across different fields.

  4. [Influences of Solenopsis invicta buren invasion on the native ant communities in different habitats in Guangdong].

    PubMed

    Wu, Bi-qiu; Lu, Yong-yue; Zeng, Ling; Liang, Guang-wen

    2008-01-01

    By using pitfall and bait traps, an investigation was made on the diversity and similarity of ant communities in the areas infested and un-infested with Solenopsis invicta Buren in Shenzhen of Guangdong. The results showed that under the invasion of S. invicta, the ant species number in lawn and wasteland reduced obviously, with a decrease of 6 in lawn and 3 in wasteland, and the native dominant ant species in lichee orchard, especially in wasteland and lawn, were replaced by S. invicta. With the infestation of S. invicta, the diversity and evenness of ant communities in wasteland and lawn decreased but the predominance increased obviously, while it was in adverse in lichee orchard. The similarity coefficients of the ant communities between S. invicta infested and un-infested lichee orchard, wasteland and lawn were 0.6316, 0.5882 and 0.2941, respectively.

  5. Attacking invasive grasses

    USGS Publications Warehouse

    Keeley, Jon E.

    2015-01-01

    In grasslands fire may play a role in the plant invasion process, both by creating disturbances that potentially favour non-native invasions and as a possible tool for controlling alien invasions. Havill et al. (Applied Vegetation Science, 18, 2015, this issue) determine how native and non-native species respond to different fire regimes as a first step in understanding the potential control of invasive grasses.

  6. Temporal Genetic Dynamics of an Invasive Species, Frankliniella occidentalis (Pergande), in an Early Phase of Establishment

    PubMed Central

    Yang, Xian-Ming; Lou, Heng; Sun, Jing-Tao; Zhu, Yi-Ming; Xue, Xiao-Feng; Hong, Xiao-Yue

    2015-01-01

    Many species can successfully colonize new areas despite their propagules having low genetic variation. We assessed whether the decreased genetic diversity could result in temporal fluctuations of genetic parameters of the new populations of an invasive species, western flower thrips, Frankliniella occidentalis, using mitochondrial and microsatellite markers. This study was conducted in eight localities from four climate regions in China, where F. occidentalis was introduced in the year 2000 and had lower genetic diversity than its native populations. We also tested the level of genetic differentiation in these introduced populations. The genetic diversity of the samples at different years in the same locality was not significantly different from each other in most localities. FST and STRUCTURE analysis also showed that most temporal population comparisons from the same sites were not significantly differentiated. Our results showed that the invasive populations of F. occidentalis in China can maintain temporal stability in genetic composition at an early phase of establishment despite having lower genetic diversity than in their native range. PMID:26138760

  7. Suppression of choriocarcinoma invasion and metastasis following blockade of BDNF/TrkB signaling.

    PubMed

    Kawamura, Kazuhiro; Kawamura, Nanami; Okamoto, Naoki; Manabe, Motomu

    2013-12-01

    Brain-derived neurotrophic factor (BDNF) acts through its cognate receptor tyrosine kinase-B (TrkB) to regulate diverse physiological functions in reproductive and other tissues. In normal and malignant trophoblastic cells, the BDNF/TrkB signaling promotes cell growth. Due to the highly malignant nature of choriocarcinoma, we investigated possible involvement of this system in choriocarcinoma cell invasion and metastasis. We demonstrated that treatment of cultured choriocarcinoma cells, known to express both BDNF and TrkB, with a soluble TrkB ectodomain or a Trk receptor inhibitor K252a suppressed cell invasion accompanied with decreased expression of matrix metalloproteinase-2, a cell invasion marker. In vivo studies using a tumor xenograft model in athymic nude mice further showed inhibition of cell invasion from tumors to surrounding tissues following the suppression of endogenous TrkB signaling. For an in vivo model of choriocarcinoma metastasis, we performed intravenous injections of JAR cells expressing firefly luciferase into severe combined immunodeficiency (SCID) mice. Treatment with K252a inhibited metastasis of tumors to distant organs. In vivo K252a treatment also suppressed metastatic tumor growth as reflected by decreased cell proliferation and increased apoptosis and caspases-3/7 activities, together with reduced tissue levels of a tumor marker, human chorionic gonadotropin-β. In vivo suppression of TrkB signaling also led to decreased expression of angiogenic markers in metastatic tumor, including cluster of differentiation 31 and vascular endothelial growth factor A. Our findings suggested essential autocrine/paracrine roles of the BDNF/TrkB signaling system in choriocarcinoma invasion and metastasis. Inhibition of this signaling could serve as the basis to develop a novel therapy for patients with choriocarcinoma.

  8. Invisible invaders: non-pathogenic invasive microbes in aquatic and terrestrial ecosystems.

    PubMed

    Litchman, Elena

    2010-12-01

    Although the number of studies on invasive plants and animals has risen exponentially, little is known about invasive microbes, especially non-pathogenic ones. Microbial invasions by viruses, bacteria, fungi and protists occur worldwide but are much harder to detect than invasions by macroorganisms. Invasive microbes have the potential to significantly alter community structure and ecosystem functioning in diverse terrestrial and aquatic ecosystems. Consequently, increased attention is needed on non-pathogenic invasive microbes, both free-living and symbiotic, and their impacts on communities and ecosystems. Major unknowns include the characteristics that make microbes invasive and properties of the resident communities and the environment that facilitate invasions. A comparison of microbial invasions with invasions of macroorganisms should provide valuable insights into general principles that apply to invasions across all domains of life and to taxon-specific invasion patterns. Invasive microbes appear to possess traits thought to be common in many invasive macroorganisms: high growth rate and resource utilization efficiency, and superior competitive abilities. Invading microorganisms are often similar to native species, but with enhanced performance traits, and tend to spread in lower diversity communities. Global change can exacerbate microbial invasions; therefore, they will likely increase in the future.

  9. Ecosystem engineers modulate exotic invasions in riparian plant communities

    NASA Astrophysics Data System (ADS)

    Corenblit, D.; Tabacchi, E.; Steiger, J.; Gonzales, E.; Planty-Tabacchi, A. M.

    2012-04-01

    The relationship between biodiversity and invasibility of exotic plant species within different environments and at different spatial scales is still being discussed amongst scientists. In this study, patterns of native and exotic plant species richness and cover were examined in relation with ecosystem engineer effects of pioneer vegetation within the active tract of the Mediterranean gravel bed river Tech, South France. The floristic composition was characterized according to two distinct vegetation types corresponding to two habitats with contrasted conditions: (i) open and exposed alluvial bars dominated by herbaceous communities and (ii) islands and river margins partly stabilized by ecosystem engineer plants, disconnected from annual hydrogeomorphic disturbances, and covered by woody vegetation. A significant positive correlation between exotic and native plant species richness and cover was observed for the herbaceous and the woody types, indicating that both native and exotic richness benefit from the prevailing environmental conditions. However, significant differences in native and exotic specific richness and cover were found between these two vegetation types. Higher values of total species richness and Shannon diversity of native and exotic species were attained within the herbaceous vegetation type compared to the woody type. These differences may be related to changes in local exposure to hydrogeomorphic disturbances driven by engineer plant species, and to vegetation succession. A lower exotic cover within the woody vegetation type compared to the herbaceous type suggested an increase of resistance to invasion by exotic species during the biogeomorphic succession. The engineer effects of woody vegetation resulted in a decrease of alpha (α) diversity at patch scale but, in parallel, caused an increase in gamma (γ) diversity at the scale of the studied river segment. Our study corroborates recent investigations that support the theory of biotic

  10. Lianas as invasive species in North America: Chapter 28

    USGS Publications Warehouse

    Leicht-Young, Stacey A.; Pavlovic, Noel B.

    2015-01-01

    Liana diversity is typically low in the temperate zones; however, the influx of non-native invasive liana species in North America has increased local diversity at the expense of native habitats and species. Some of the most illustrative studies of invasive lianas in temperate North America compared the biological traits of invasive lianas with native congeners or ecological analogs. The majority of these studies focused on two species, Celastrus orbiculatus (oriental bittersweet) and Lonicera japonica (Japanese honeysuckle). Temperate zone lianas generally have higher photosynthetic rates than other early successional species and their host trees. Invasive lianas are having an increasing impact on the dynamics and trajectories of North American plant communities. They often exhibit superior growth and survival compared to their native counterparts, and in some cases, invasive lianas may directly contribute to the decline of their native correlates.

  11. Production of Early Diploid Males by European Colonies of the Invasive Hornet Vespa velutina nigrithorax

    PubMed Central

    Darrouzet, Eric; Gévar, Jérémy; Guignard, Quentin; Aron, Serge

    2015-01-01

    The invasive yellow-legged hornet Vespa velutina nigrithorax was accidentally introduced in Europe in the early 2000s. As is the case in colonies of other wasp and hornet species, V. velutina colonies are known to produce sexuals (males and new queens) at the end of the summer. We show that early-stage colonies in French populations frequently produce males well before the usual reproductive period. The vast majority of the males produced are diploid, which is consistent with the loss of genetic diversity previously reported in introduced populations in France. Since males do not participate in colony activities, the production of early diploid males at the expense of workers is expected to hamper colony growth and, ultimately, decrease the expansion of the species in its invasive range in Europe. PMID:26414951

  12. Production of Early Diploid Males by European Colonies of the Invasive Hornet Vespa velutina nigrithorax.

    PubMed

    Darrouzet, Eric; Gévar, Jérémy; Guignard, Quentin; Aron, Serge

    2015-01-01

    The invasive yellow-legged hornet Vespa velutina nigrithorax was accidentally introduced in Europe in the early 2000s. As is the case in colonies of other wasp and hornet species, V. velutina colonies are known to produce sexuals (males and new queens) at the end of the summer. We show that early-stage colonies in French populations frequently produce males well before the usual reproductive period. The vast majority of the males produced are diploid, which is consistent with the loss of genetic diversity previously reported in introduced populations in France. Since males do not participate in colony activities, the production of early diploid males at the expense of workers is expected to hamper colony growth and, ultimately, decrease the expansion of the species in its invasive range in Europe.

  13. The role thermal physiology plays in species invasion

    PubMed Central

    Kelley, Amanda L.

    2014-01-01

    The characterization of physiological phenotypes that may play a part in the establishment of non-native species can broaden our understanding about the ecology of species invasion. Here, an assessment was carried out by comparing the responses of invasive and native species to thermal stress. The goal was to identify physiological patterns that facilitate invasion success and to investigate whether these traits are widespread among invasive ectotherms. Four hypotheses were generated and tested using a review of the literature to determine whether they could be supported across taxonomically diverse invasive organisms. The four hypotheses are as follows: (i) broad geographical temperature tolerances (thermal width) confer a higher upper thermal tolerance threshold for invasive rather than native species; (ii) the upper thermal extreme experienced in nature is more highly correlated with upper thermal tolerance threshold for invasive vs. native animals; (iii) protein chaperone expression—a cellular mechanism that underlies an organism's thermal tolerance threshold—is greater in invasive organisms than in native ones; and (iv) acclimation to higher temperatures can promote a greater range of thermal tolerance for invasive compared with native species. Each hypothesis was supported by a meta-analysis of the invasive/thermal physiology literature, providing further evidence that physiology plays a substantial role in the establishment of invasive ectotherms. PMID:27293666

  14. Population genetics of the invasive cryptogenic anemone, Anemonia alicemartinae, along the southeastern Pacific coast

    NASA Astrophysics Data System (ADS)

    Canales-Aguirre, C. B.; Quiñones, A.; Hernández, C. E.; Neill, P. E.; Brante, A.

    2015-08-01

    One of the most important issues in biological invasions is understanding the factors and mechanisms determining the invasion success of non-native species. Theoretical and empirical works have shown that genetic diversity is a determinant of invasion success; thus, studying spatial patterns of genetic diversity, and exploring how biological and physical factors shape this population trait, are fundamental for understanding this phenomenon. Coastal marine ecosystems are one of the most susceptible habitats to invasion given the complex network of maritime transport. In this work we study the cryptogenic anemone, Anemonia alicemartinae, which has rapidly increased its geographical range southward during the last 50 years (approx. 2000 km) along the southeastern Pacific coast. Based on COI mtDNA sequences we evaluated three main hypotheses: a) the genetic diversity of A. alicemartinae decreases according to the direction of invasion (from north to south); b) there is biogeographic-phylogeographic concordance at the 30°S biogeographic break; and c) the demographic history is coherent with a recent geographic expansion. A total of 161 individual samples of A. alicemartinae were collected along the southeastern Pacific coast range of distribution, covering more than 2000 km, including samples along the 30°S biogeographical break. Results showed low genetic diversity (Hd = 0.253; π = 0.08) and a lack of geographic population genetic structure (FST = - 0.009, p-value = 0.656). The highest genetic diversity was observed in Peru (Chero and Mesas) and at localities close to the main Chilean seaports. We did not observe concordance between biogeographic and phylogeographic patterns or isolation by distance. Demographic indices (D = - 2.604, p < 0.001; Fu's = - 26.619, p < 0.001), as well as a star-like configuration of the haplotype network support recent population expansion of this species. Our results, together with historical field observations, support the idea that

  15. Junction Protein Shrew-1 Influences Cell Invasion and Interacts with Invasion-promoting Protein CD147

    PubMed Central

    Schreiner, Alexander; Ruonala, Mika; Jakob, Viktor; Suthaus, Jan; Boles, Eckhard; Wouters, Fred

    2007-01-01

    Shrew-1 was previously isolated from an endometriotic cell line in our search for invasion-associated genes. It proved to be a membrane protein that targets to the basolateral membrane of polarized epithelial cells, interacting with E-cadherin–catenin complexes of adherens junctions. Paradoxically, the existence of adherens junctions is incompatible with invasion. To investigate whether shrew-1 can indeed influence cellular invasion, we overexpressed it in HT1080 fibrosarcoma cells. This resulted in enhanced invasiveness, accompanied by an increased matrix metalloprotease (MMP)-9 level in the supernatant, raising the question about the role of shrew-1 in this process. Logic suggested we looked for an interaction with CD147, a known promoter of invasiveness and MMP activity. Indeed, genetics-based, biochemical, and microscopy experiments revealed shrew-1– and CD147-containing complexes in invasive endometriotic cells and an interaction in epithelial cells, which was stronger in MCF7 tumor cells, but weaker in Madin-Darby canine kidney cells. In contrast to the effect mediated by overexpression, small interfering RNA-mediated down-regulation of either shrew-1 or CD147 in HeLa cells decreased invasiveness without affecting the proliferation behavior of HeLa cells, but the knockdown cells displayed decreased motility. Altogether, our results imply that shrew-1 has a function in the regulation of cellular invasion, which may involve its interaction with CD147. PMID:17267690

  16. Freshwater ecosystems and aquatic insects: a paradox in biological invasions.

    PubMed

    Fenoglio, Stefano; Bonada, Núria; Guareschi, Simone; López-Rodríguez, Manuel J; Millán, Andrés; Tierno de Figueroa, J Manuel

    2016-04-01

    Biological invasions have increased significantly in response to global change and constitute one of the major causes of biodiversity loss. Insects make up a large fraction of invasive species, in general, and freshwaters are among the most invaded ecosystems on our planet. However, even though aquatic insects dominate most inland waters, have unparalleled taxonomic diversity and occupy nearly all trophic niches, there are almost no invasive insects in freshwaters. We present some hypotheses regarding why aquatic insects are not common among aquatic invasive organisms, suggesting that it may be the result of a suite of biological, ecological and anthropogenic factors. Such specific knowledge introduces a paradox in the current scientific discussion on invasive species; therefore, a more in-depth understanding could be an invaluable aid to disentangling how and why biological invasions occur.

  17. Freshwater ecosystems and aquatic insects: a paradox in biological invasions.

    PubMed

    Fenoglio, Stefano; Bonada, Núria; Guareschi, Simone; López-Rodríguez, Manuel J; Millán, Andrés; Tierno de Figueroa, J Manuel

    2016-04-01

    Biological invasions have increased significantly in response to global change and constitute one of the major causes of biodiversity loss. Insects make up a large fraction of invasive species, in general, and freshwaters are among the most invaded ecosystems on our planet. However, even though aquatic insects dominate most inland waters, have unparalleled taxonomic diversity and occupy nearly all trophic niches, there are almost no invasive insects in freshwaters. We present some hypotheses regarding why aquatic insects are not common among aquatic invasive organisms, suggesting that it may be the result of a suite of biological, ecological and anthropogenic factors. Such specific knowledge introduces a paradox in the current scientific discussion on invasive species; therefore, a more in-depth understanding could be an invaluable aid to disentangling how and why biological invasions occur. PMID:27072403

  18. Effects of Invasive-Plant Management on Nitrogen-Removal Services in Freshwater Tidal Marshes.

    PubMed

    Alldred, Mary; Baines, Stephen B; Findlay, Stuart

    2016-01-01

    Establishing relationships between biodiversity and ecosystem function is an ongoing endeavor in contemporary ecosystem and community ecology, with important practical implications for conservation and the maintenance of ecosystem services. Removal of invasive plant species to conserve native diversity is a common management objective in many ecosystems, including wetlands. However, substantial changes in plant community composition have the potential to alter sediment characteristics and ecosystem services, including permanent removal of nitrogen from these systems via microbial denitrification. A balanced assessment of costs associated with keeping and removing invasive plants is needed to manage simultaneously for biodiversity and pollution targets. We monitored small-scale removals of Phragmites australis over four years to determine their effects on potential denitrification rates relative to three untreated Phragmites sites and adjacent sites dominated by native Typha angustifolia. Sediment ammonium increased following the removal of vegetation from treated sites, likely as a result of decreases in both plant uptake and nitrification. Denitrification potentials were lower in removal sites relative to untreated Phragmites sites, a pattern that persisted at least two years following removal as native plant species began to re-colonize treated sites. These results suggest the potential for a trade-off between invasive-plant management and nitrogen-removal services. A balanced assessment of costs associated with keeping versus removing invasive plants is needed to adequately manage simultaneously for biodiversity and pollution targets.

  19. Effects of Invasive-Plant Management on Nitrogen-Removal Services in Freshwater Tidal Marshes.

    PubMed

    Alldred, Mary; Baines, Stephen B; Findlay, Stuart

    2016-01-01

    Establishing relationships between biodiversity and ecosystem function is an ongoing endeavor in contemporary ecosystem and community ecology, with important practical implications for conservation and the maintenance of ecosystem services. Removal of invasive plant species to conserve native diversity is a common management objective in many ecosystems, including wetlands. However, substantial changes in plant community composition have the potential to alter sediment characteristics and ecosystem services, including permanent removal of nitrogen from these systems via microbial denitrification. A balanced assessment of costs associated with keeping and removing invasive plants is needed to manage simultaneously for biodiversity and pollution targets. We monitored small-scale removals of Phragmites australis over four years to determine their effects on potential denitrification rates relative to three untreated Phragmites sites and adjacent sites dominated by native Typha angustifolia. Sediment ammonium increased following the removal of vegetation from treated sites, likely as a result of decreases in both plant uptake and nitrification. Denitrification potentials were lower in removal sites relative to untreated Phragmites sites, a pattern that persisted at least two years following removal as native plant species began to re-colonize treated sites. These results suggest the potential for a trade-off between invasive-plant management and nitrogen-removal services. A balanced assessment of costs associated with keeping versus removing invasive plants is needed to adequately manage simultaneously for biodiversity and pollution targets. PMID:26914688

  20. Involvement of ephrin receptor A4 in pancreatic cancer cell motility and invasion

    PubMed Central

    LIU, CHENGLI; HUANG, HUI; WANG, CHENG; KONG, YALIN; ZHANG, HONGYI

    2014-01-01

    Ephrin (EPH) receptors can be classified into EPHA and EPHB receptors and are important in diverse cellular processes. EPHA4, a member of the EPHA receptors, has been demonstrated to be elevated in various human cancers and involved in the tumor progression. However, the role of EPHA4 in pancreatic cancer cells remains unclear. Therefore, the present study transfected Panc-1 and BxPC-3 cells with small interfering RNA (siRNA) to knockdown the expression of EPHA4. Wound healing and invasion assays were then performed to assess the effect of EPHA4 knockdown on the motility and invasion of pancreatic cancer cells. The results demonstrated that the knockdown of EPHA4 by siRNA inhibits the motility and invasion of pancreatic cancer cells. Furthermore, gelatin zymography assay showed that EPHA4 may regulate the activity of matrix metalloproteinase (MMP)-2. In addition, the knockdown of EPHA4 increased the expression of epithelial (E)-cadherin, as well as decreased the expression of Snail. Overall, these results suggested that EPHA4 may promote the motility and invasion of pancreatic cancer cells via the upregulation of MMP-2 and Snail, as well as the downregulation of E-cadherin. Thus, EPHA4 may act as a useful target for the treatment of pancreatic cancer. PMID:24932309

  1. Effects of Invasive-Plant Management on Nitrogen-Removal Services in Freshwater Tidal Marshes

    PubMed Central

    Alldred, Mary; Baines, Stephen B.; Findlay, Stuart

    2016-01-01

    Establishing relationships between biodiversity and ecosystem function is an ongoing endeavor in contemporary ecosystem and community ecology, with important practical implications for conservation and the maintenance of ecosystem services. Removal of invasive plant species to conserve native diversity is a common management objective in many ecosystems, including wetlands. However, substantial changes in plant community composition have the potential to alter sediment characteristics and ecosystem services, including permanent removal of nitrogen from these systems via microbial denitrification. A balanced assessment of costs associated with keeping and removing invasive plants is needed to manage simultaneously for biodiversity and pollution targets. We monitored small-scale removals of Phragmites australis over four years to determine their effects on potential denitrification rates relative to three untreated Phragmites sites and adjacent sites dominated by native Typha angustifolia. Sediment ammonium increased following the removal of vegetation from treated sites, likely as a result of decreases in both plant uptake and nitrification. Denitrification potentials were lower in removal sites relative to untreated Phragmites sites, a pattern that persisted at least two years following removal as native plant species began to re-colonize treated sites. These results suggest the potential for a trade-off between invasive-plant management and nitrogen-removal services. A balanced assessment of costs associated with keeping versus removing invasive plants is needed to adequately manage simultaneously for biodiversity and pollution targets. PMID:26914688

  2. A review of invasive Haemophilus influenzae disease in the Indigenous populations of North America.

    PubMed

    Tsang, R S W; Bruce, M G; Lem, M; Barreto, L; Ulanova, M

    2014-07-01

    Historically, the highest incidence rates of invasive Haemophilus influenzae disease in the world were found in North American and Australian Indigenous children. Although immunization against H. influenzae type b (Hib) led to a marked decrease in invasive Hib disease in countries where it was implemented, this disease has not been eliminated and its rates in Indigenous communities remain higher than in the general North American population. In this literature review, we examined the epidemiology of invasive H. influenzae disease in the pre-Hib vaccine era, effect of carriage on disease epidemiology, immune response to H. influenzae infection and Hib vaccination in Indigenous and Caucasian children, and the changing epidemiology after Hib conjugate vaccine has been in use for more than two decades in North America. We also explored reasons behind the continued high rates of invasive H. influenzae disease in Indigenous populations in North America. H. influenzae type a (Hia) has emerged as a significant cause of severe disease in North American Indigenous communities. More research is needed to define the genotypic diversity of Hia and the disease burden that it causes in order to determine if a Hia vaccine is required to protect the vulnerable populations.

  3. Heterogeneity of clonal patterns among patches of kudzu, Pueraria montana var. lobata, an invasive plant

    PubMed Central

    Kartzinel, Tyler R.; Hamrick, J. L.; Wang, Chongyun; Bowsher, Alan W.; Quigley, Bryan G. P.

    2015-01-01

    Background and Aims Viny species are among the most serious invasive plants, and better knowledge of how vines grow to dominate landscapes is needed. Patches may contain a single genotype (i.e. genet), a competitively dominant genet or many independent but interacting genets, yet the clonal structure of vining species is often not apparent. Molecular markers can discriminate among the genetic identities of entwined vines to reveal the number and spatial distribution of genets. This study investigated how genets are spatially distributed within and among discrete patches of the invasive vine kudzu, Pueraria montana var. lobata, in the United States. It was expected that ramets of genets would be spatially clustered within patches, and that an increase in the number of genets within a patch would be associated with a decrease in the average size of each genet. Methods Six discrete kudzu patches were sampled across 2 years, and 1257 samples were genotyped at 21 polymorphic allozyme loci. Variation in genotypic and genetic diversity among patches was quantified and patterns of genet interdigitation were analysed. Key Results Substantial genotypic and genetic variation occurred within and among patches. As few as ten overlapping genets spanned up to 68 m2 in one patch, while >90 % of samples were genetically unique in another patch. Genotypic diversity within patches increased as mean clone size decreased, although spatially widespread genets did not preclude interdigitation. Eight genets were shared across ≥2 patches, suggesting that vegetative dispersal can occur among patches. Conclusions Genetically unique kudzu vines are highly interdigitated. Multiple vegetative propagules have become established in spatially discrete patches, probably through the movement of highway construction or maintenance machinery. The results suggest that common methods for controlling invasive vines (e.g. mowing) may inadvertently increase genotypic diversity. Thus, understanding

  4. Paradigm of plant invasion: multifaceted review on sustainable management.

    PubMed

    Rai, Prabhat Kumar

    2015-12-01

    A cascade of reviews and growing body of literature exists on forest invasion ecology, its mechanism or causes; however, no review addressed the sustainable management of invasive plants of forest in totality. Henceforth, the present paper aims to provide a critical review on the management of invasive species particularly in the context of forest plants. Plant invasion in forest is now increasingly being recognized as a global problem, and various continents are adversely affected, although to a differential scale. Quest for the ecological mechanism lying behind the success of invasive species over native species of forest has drawn the attention of researches worldwide particularly in the context of diversity-stability relationship. Transport, colonization, establishment, and landscape spread may be different steps in success of invasive plants in forest, and each and every step is checked through several ecological attributes. Further, several ecological attribute and hypothesis (enemy release, novel weapon, empty niche, evolution of increased competitive ability, etc.) were proposed pertaining to success of invasive plant species in forest ecosystems. However, a single theory will not be able to account for invasion success among all environments as it may vary spatially and temporally. Therefore, in order to formulate a sustainable management plan for invasive plants of forest, it is necessary to develop a synoptic view of the dynamic processes involved in the invasion process. Moreover, invasive species of forest can act synergistically with other elements of global change, including land-use change, climate change, increased concentrations of atmospheric carbon dioxide, and nitrogen deposition. Henceforth, a unified framework for biological invasions that reconciles and integrates the key features of the most commonly used invasion frameworks into a single conceptual model that can be applied to all human-mediated invasions.

  5. Paradigm of plant invasion: multifaceted review on sustainable management.

    PubMed

    Rai, Prabhat Kumar

    2015-12-01

    A cascade of reviews and growing body of literature exists on forest invasion ecology, its mechanism or causes; however, no review addressed the sustainable management of invasive plants of forest in totality. Henceforth, the present paper aims to provide a critical review on the management of invasive species particularly in the context of forest plants. Plant invasion in forest is now increasingly being recognized as a global problem, and various continents are adversely affected, although to a differential scale. Quest for the ecological mechanism lying behind the success of invasive species over native species of forest has drawn the attention of researches worldwide particularly in the context of diversity-stability relationship. Transport, colonization, establishment, and landscape spread may be different steps in success of invasive plants in forest, and each and every step is checked through several ecological attributes. Further, several ecological attribute and hypothesis (enemy release, novel weapon, empty niche, evolution of increased competitive ability, etc.) were proposed pertaining to success of invasive plant species in forest ecosystems. However, a single theory will not be able to account for invasion success among all environments as it may vary spatially and temporally. Therefore, in order to formulate a sustainable management plan for invasive plants of forest, it is necessary to develop a synoptic view of the dynamic processes involved in the invasion process. Moreover, invasive species of forest can act synergistically with other elements of global change, including land-use change, climate change, increased concentrations of atmospheric carbon dioxide, and nitrogen deposition. Henceforth, a unified framework for biological invasions that reconciles and integrates the key features of the most commonly used invasion frameworks into a single conceptual model that can be applied to all human-mediated invasions. PMID:26581605

  6. Are boreal ecosystems susceptible to alien plant invasion? Evidence from protected areas.

    PubMed

    Rose, Michael; Hermanutz, Luise

    2004-05-01

    Although biological invasion by alien species is a major contributor to loss of indigenous biological diversity, few studies have examined the susceptibility of the boreal biome to invasion. Based on studies of other ecosystems, we hypothesized that alien plants will be restricted to disturbed areas near human activity and will not be found in natural areas of boreal ecosystems in Gros Morne National Park (Canada), a protected area experiencing a wide range of disturbance regimes. The distribution of alien plants in the region was evaluated using surveys, and study sites were established in naturally and anthropogenically disturbed habitats that had been invaded. Within study sites, randomization tests evaluated the importance of disturbance to alien plant invasion by examining changes in environmental conditions and species abundance within various disturbance regimes, while the importance of site characteristics limiting the distribution of alien plants were examined using Canonical Correspondence Analysis. Consistent with studies in a variety of biomes, areas of high disturbance and human activity had the greatest abundance of resources and the highest percentage of alien species. However, contrary to our hypothesis, natural areas of boreal ecosystems were found susceptible to alien plant invasion. Vegetation types vulnerable to invasion include forests, riparian areas, fens, and alpine meadows. Natural disturbance occurring in these vegetation types caused increases in bare ground and/or light availability facilitating alien plant invasion. Although high soil pH was associated with alien plants in these areas, disturbance was not found to cause changes in soil pH, suggesting susceptibility to invasion is pre-determined by bedrock geology or other factors influencing soil pH. Moose (Alces alces), a non-native herbivore, acts as the primary conduit for alien plant invasion in GMNP by dispersing propagules and creating or prolonging disturbance by trampling and

  7. Selection on herbivory resistance and growth rate in an invasive plant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive species face different conditions in their new range, which may lead to evolutionary change. The evolution of increased competitive ability (EICA) hypothesis proposes that invasive species evolve decreased defense and increased growth rate and competitive ability following introduction. W...

  8. Urinary diversion after cystectomy: An Indian perspective

    PubMed Central

    Jain, Deepak; Raghunath, S. K.; Khanna, Samir; Kumar, Prem; Rawal, Sudhir

    2008-01-01

    Radical cystectomy remains the standard treatment for muscle-invasive carcinoma bladder. Various methods have been described for the urinary diversion. In the last 150 years urinary diversion has evolved from cutaneous ureterostomy to the orthotopic neobladder. Especially during the last 20 years, much advancement has been made. We hereby have reviewed the current approaches being used at different centers in India. We have also analyzed the evolution of diversion from conduit to the orthotopic substitution at our center. PMID:19468368

  9. Rethinking Diversity.

    ERIC Educational Resources Information Center

    Gordon, Jack

    1992-01-01

    Managing diversity is about coping with unassimilated differences, about building systems and a culture that unite different people in a common pursuit without undermining their diversity. The goal of diversity training is a high performance organization rather than a climate in which no one's feathers are ruffled. (SK)

  10. Genetic diversity enhances the resistance of a seagrass ecosystem to disturbance

    PubMed Central

    Hughes, A. Randall; Stachowicz, John J.

    2004-01-01

    Motivated by recent global reductions in biodiversity, empirical and theoretical research suggests that more species-rich systems exhibit enhanced productivity, nutrient cycling, or resistance to disturbance or invasion relative to systems with fewer species. In contrast, few data are available to assess the potential ecosystem-level importance of genetic diversity within species known to play a major functional role. Using a manipulative field experiment, we show that increasing genotypic diversity in a habitat-forming species (the seagrass Zostera marina) enhances community resistance to disturbance by grazing geese. The time required for recovery to near predisturbance densities also decreases with increasing eelgrass genotypic diversity. However, there is no effect of diversity on resilience, measured as the rate of shoot recovery after the disturbance, suggesting that more rapid recovery in diverse plots is due solely to differences in disturbance resistance. Genotypic diversity did not affect ecosystem processes in the absence of disturbance. Thus, our results suggest that genetic diversity, like species diversity, may be most important for enhancing the consistency and reliability of ecosystems by providing biological insurance against environmental change. PMID:15184681

  11. Abiotic constraints eclipse biotic resistance in determining invasibility along experimental vernal pool gradients.

    PubMed

    Gerhardt, Fritz; Collinge, Sharon K

    2007-04-01

    Effective management of invasive species requires that we understand the mechanisms determining community invasibility. Successful invaders must tolerate abiotic conditions and overcome resistance from native species in invaded habitats. Biotic resistance to invasions may reflect the diversity, abundance, or identity of species in a community. Few studies, however, have examined the relative importance of abiotic and biotic factors determining community invasibility. In a greenhouse experiment, we simulated the abiotic and biotic gradients typically found in vernal pools to better understand their impacts on invasibility. Specifically, we invaded plant communities differing in richness, identity, and abundance of native plants (the "plant neighborhood") and depth of inundation to measure their effects on growth, reproduction, and survival of five exotic plant species. Inundation reduced growth, reproduction, and survival of the five exotic species more than did plant neighborhood. Inundation reduced survival of three species and growth and reproduction of all five species. Neighboring plants reduced growth and reproduction of three species but generally did not affect survival. Brassica rapa, Centaurea solstitialis, and Vicia villosa all suffered high mortality due to inundation but were generally unaffected by neighboring plants. In contrast, Hordeum marinum and Lolium multiflorum, whose survival was unaffected by inundation, were more impacted by neighboring plants. However, the four measures describing plant neighborhood differed in their effects. Neighbor abundance impacted growth and reproduction more than did neighbor richness or identity, with growth and reproduction generally decreasing with increasing density and mass of neighbors. Collectively, these results suggest that abiotic constraints play the dominant role in determining invasibility along vernal pool and similar gradients. By reducing survival, abiotic constraints allow only species with the

  12. Genetic diversity in two introduced biofouling amphipods (Amphipods valida and Jassa marmorata) along the Pacific North American coast: investigation into molecular identification and cryptic diversity

    EPA Science Inventory

    We investigated patterns of genetic diversity among invasive populations of A. valida and J. marmorata from the Pacific North American coast to assess the accuracy of morphological identification and determine whether or not cryptic diversity and multiple introductions contribute...

  13. Epigenetic suppression of neprilysin regulates breast cancer invasion

    PubMed Central

    Stephen, H M; Khoury, R J; Majmudar, P R; Blaylock, T; Hawkins, K; Salama, M S; Scott, M D; Cosminsky, B; Utreja, N K; Britt, J; Conway, R E

    2016-01-01

    In women, invasive breast cancer is the second most common cancer and the second cause of cancer-related death. Therefore, identifying novel regulators of breast cancer invasion could lead to additional biomarkers and therapeutic targets. Neprilysin, a cell-surface enzyme that cleaves and inactivates a number of substrates including endothelin-1 (ET1), has been implicated in breast cancer, but whether neprilysin promotes or inhibits breast cancer cell progression and metastasis is unclear. Here, we asked whether neprilysin expression predicts and functionally regulates breast cancer cell invasion. RT–PCR and flow cytometry analysis of MDA-MB-231 and MCF-7 breast cancer cell lines revealed decreased neprilysin expression compared with normal epithelial cells. Expression was also suppressed in invasive ductal carcinoma (IDC) compared with normal tissue. In addition, in vtro invasion assays demonstrated that neprilysin overexpression decreased breast cancer cell invasion, whereas neprilysin suppression augmented invasion. Furthermore, inhibiting neprilysin in MCF-7 breast cancer cells increased ET1 levels significantly, whereas overexpressing neprilysin decreased extracellular-signal related kinase (ERK) activation, indicating that neprilysin negatively regulates ET1-induced activation of mitogen-activated protein kinase (MAPK) signaling. To determine whether neprilysin was epigenetically suppressed in breast cancer, we performed bisulfite conversion analysis of breast cancer cells and clinical tumor samples. We found that the neprilysin promoter was hypermethylated in breast cancer; chemical reversal of methylation in MDA-MB-231 cells reactivated neprilysin expression and inhibited cancer cell invasion. Analysis of cancer databases revealed that neprilysin methylation significantly associates with survival in stage I IDC and estrogen receptor-negative breast cancer subtypes. These results demonstrate that neprilysin negatively regulates the ET axis in breast cancer

  14. Minimally Invasive Surgery in Gynecologic Oncology

    PubMed Central

    Mori, Kristina M.; Neubauer, Nikki L.

    2013-01-01

    Minimally invasive surgery has been utilized in the field of obstetrics and gynecology as far back as the 1940s when culdoscopy was first introduced as a visualization tool. Gynecologists then began to employ minimally invasive surgery for adhesiolysis and obtaining biopsies but then expanded its use to include procedures such as tubal sterilization (Clyman (1963), L. E. Smale and M. L. Smale (1973), Thompson and Wheeless (1971), Peterson and Behrman (1971)). With advances in instrumentation, the first laparoscopic hysterectomy was successfully performed in 1989 by Reich et al. At the same time, minimally invasive surgery in gynecologic oncology was being developed alongside its benign counterpart. In the 1975s, Rosenoff et al. reported using peritoneoscopy for pretreatment evaluation in ovarian cancer, and Spinelli et al. reported on using laparoscopy for the staging of ovarian cancer. In 1993, Nichols used operative laparoscopy to perform pelvic lymphadenectomy in cervical cancer patients. The initial goals of minimally invasive surgery, not dissimilar to those of modern medicine, were to decrease the morbidity and mortality associated with surgery and therefore improve patient outcomes and patient satisfaction. This review will summarize the history and use of minimally invasive surgery in gynecologic oncology and also highlight new minimally invasive surgical approaches currently in development. PMID:23997959

  15. [Minimally Invasive Open Surgery for Lung Cancer].

    PubMed

    Nakagawa, Kazuo; Watanabe, Shunichi

    2016-07-01

    Significant efforts have been made to reduce the invasiveness of surgical procedures by surgeons for a long time. Surgeons always keep it in mind that the basic principle performing less invasive surgical procedures for malignant tumors is to decrease the invasiveness for patients without compromising oncological curability and surgical safety. Video-assisted thoracic surgery (VATS) has been used increasingly as a minimally invasive approach to lung cancer surgery. Whereas, whether VATS lobectomy is a less invasive procedure and has equivalent or better clinical effect compared with open lobectomy for patients with lung cancer remains controversial because of the absence of randomized prospective studies. The degree of difficulty for anatomical lung resection depends on the degree of the fissure development, mobility of hilar lymph nodes, and the degree of pleural adhesions. During pulmonary surgery, thoracic surgeons always have to deal with not only these difficulties but other unexpected events such as intraoperative bleeding. Recently, we perform pulmonary resection for lung cancer with minimally invasive open surgery (MIOS) approach. In this article, we introduce the surgical procedure of MIOS and demonstrate short-term results. Off course, the efficacy of MIOS needs to be further evaluated with long-term results. PMID:27440030

  16. Minimally Invasive Valve Surgery

    PubMed Central

    Pope, Nicolas H.; Ailawadi, Gorav

    2014-01-01

    Cardiac valve surgery is life saving for many patients. The advent of minimally invasive surgical techniques has historically allowed for improvement in both post-operative convalescence and important clinical outcomes. The development of minimally invasive cardiac valve repair and replacement surgery over the past decade is poised to revolutionize the care of cardiac valve patients. Here, we present a review of the history and current trends in minimally invasive aortic and mitral valve repair and replacement, including the development of sutureless bioprosthetic valves. PMID:24797148

  17. Emergence and accumulation of novel pathogens suppress an invasive species.

    PubMed

    Stricker, Kerry Bohl; Harmon, Philip F; Goss, Erica M; Clay, Keith; Luke Flory, S

    2016-04-01

    Emerging pathogens are a growing threat to human health, agriculture and the diversity of ecological communities but may also help control problematic species. Here we investigated the diversity, distribution and consequences of emerging fungal pathogens infecting an aggressive invasive grass that is rapidly colonising habitats throughout the eastern USA. We document the recent emergence and accumulation over time of diverse pathogens that are members of a single fungal genus and represent multiple, recently described or undescribed species. We also show that experimental suppression of these pathogens increased host performance in the field, demonstrating the negative effects of emerging pathogens on invasive plants. Our results suggest that invasive species can facilitate pathogen emergence and amplification, raising concerns about movement of pathogens among agricultural, horticultural, and wild grasses. However, one possible benefit of pathogen accumulation is suppression of aggressive invaders over the long term, potentially abating their negative impacts on native communities.

  18. Insect-Flower Interaction Network Structure Is Resilient to a Temporary Pulse of Floral Resources from Invasive Rhododendron ponticum

    PubMed Central

    Tiedeken, Erin Jo; Stout, Jane C.

    2015-01-01

    Invasive alien plants can compete with native plants for resources, and may ultimately decrease native plant diversity and/or abundance in invaded sites. This could have consequences for native mutualistic interactions, such as pollination. Although invasive plants often become highly connected in plant-pollinator interaction networks, in temperate climates they usually only flower for part of the season. Unless sufficient alternative plants flower outside this period, whole-season floral resources may be reduced by invasion. We hypothesized that the cessation of flowering of a dominant invasive plant would lead to dramatic, seasonal compositional changes in plant-pollinator communities, and subsequent changes in network structure. We investigated variation in floral resources, flower-visiting insect communities, and interaction networks during and after the flowering of invasive Rhododendron ponticum in four invaded Irish woodland sites. Floral resources decreased significantly after R. ponticum flowering, but the magnitude of the decrease varied among sites. Neither insect abundance nor richness varied between the two periods (during and after R. ponticum flowering), yet insect community composition was distinct, mostly due to a significant reduction in Bombus abundance after flowering. During flowering R. ponticum was frequently visited by Bombus; after flowering, these highly mobile pollinators presumably left to find alternative floral resources. Despite compositional changes, however, network structural properties remained stable after R. ponticum flowering ceased: generality increased, but quantitative connectance, interaction evenness, vulnerability, H’2 and network size did not change. This is likely because after R. ponticum flowering, two to three alternative plant species became prominent in networks and insects increased their diet breadth, as indicated by the increase in network-level generality. We conclude that network structure is robust to

  19. Inbreeding depression is purged in the invasive insect Harmonia axyridis.

    PubMed

    Facon, Benoît; Hufbauer, Ruth A; Tayeh, Ashraf; Loiseau, Anne; Lombaert, Eric; Vitalis, Renaud; Guillemaud, Thomas; Lundgren, Jonathan G; Estoup, Arnaud

    2011-03-01

    Bottlenecks in population size reduce genetic diversity and increase inbreeding, which can lead to inbreeding depression. It is thus puzzling how introduced species, which typically pass through bottlenecks, become such successful invaders. However, under certain theoretical conditions, bottlenecks of intermediate size can actually purge the alleles that cause inbreeding depression. Although this process has been confirmed in model laboratory systems, it has yet to be observed in natural invasive populations. We evaluate whether such purging could facilitate biological invasions by using the world-wide invasion of the ladybird (or ladybug) Harmonia axyridis. We first show that invasive populations endured a bottleneck of intermediate intensity. We then demonstrate that replicate introduced populations experience almost none of the inbreeding depression suffered by native populations. Thus, rather than posing a barrier to invasion as often assumed, bottlenecks, by purging deleterious alleles, can enable the evolution of invaders that maintain high fitness even when inbred. PMID:21333536

  20. Implications of invasion by Juniperus virginiana on small mammals in the southern Great Plains

    USGS Publications Warehouse

    Horncastle, V.J.; Hellgren, E.C.; Mayer, P.M.; Ganguli, A.C.; Engle, David M.; Leslie, David M.

    2005-01-01

    Changes in landscape cover in the Great Plains are resulting from the range expansion and invasion of eastern red cedar (Juniperus virginiana). By altering the landscape and local vegetation, red cedar is changing the structure and function of habitat for small mammals. We examined effects of invasion by eastern red cedar on small mammals in 3 plant communities (tallgrass prairie, old field, and cross-timbers forest) in the cross-timbers ecoregion in Oklahoma. We sampled small mammals seasonally from May 2001 to August 2002 by using Sherman live traps and mark-recapture techniques on 3.24-ha, 450-trap grids in each plant community. We sampled vegetation in two hundred twenty-five 12 x 12-m cells within each grid. The structure of the small-mammal community differed among the 3 habitat types, with higher species diversity and richness in the tallgrass-prairie and old-field sites. Overall, the small-mammal community shifted along a gradient of increasing eastern red cedar. In the old-field and tallgrass-prairie plots, occurrence of grassland mammals decreased with increasing red cedar, whereas only 1 woodland mammal species increased. In the cross-timbers forest site, percent woody cover (<1 m in height), rather than cover of red cedar, was the most important factor affecting woodland mammal species. Examination of our data suggests that an increase in overstory cover from 0% to 30% red cedar can change a species-rich prairie community to a depauperate community dominated by 1 species, Peromyscus leucopus. Losses in species diversity and changes in mammal distribution paralleled those seen in avian communities invaded by eastern red cedar. Our results highlight ecological effects of invasion by eastern red cedar on diversity and function at multiple trophic levels. ?? 2005 American Society of Mammalogists.

  1. Range expansion of invasive shrubs: implication for crown fire risk in forestlands of the southern USA

    PubMed Central

    Wang, Hsiao-Hsuan; Wonkka, Carissa L.; Grant, William E.; Rogers, William E.

    2016-01-01

    Non-native plant invasions and changing management activities have dramatically altered the structure and composition of forests worldwide. Invasive shrubs and fire suppression have led to increased densification and biomass accumulation in forest ecosystems of the southeastern USA. Notably, Chinese and European privets are rapid growing, shade-tolerant shrubs which number among the most aggressive invasive species in these forests. Privet encroachment has caused losses of native diversity, alteration of ecosystem processes and changes in community structure. The latter has become manifest through decreases in fine herbaceous fuels concurrent with increases in coarse woody fuels in forest understoreys. These alterations in fuel structure will potentially lead to less frequent, but more severe forest fires, which threaten important forest resources during extreme weather conditions. Drawing on extensive data sets compiled by the US Forest Service, we integrated statistical forecasting and analytical techniques within a spatially explicit, agent-based, simulation framework to predict potential range expansion of Chinese and European privet (Ligustrum sinense and L. vulgare) and the associated increase in crown fire risk over the next two decades in forestlands of Mississippi and Alabama. Our results indicate that probability of invasion is positively associated with elevation, adjacency (within 300 m) to water bodies, mean daily maximum temperature, site productivity and private land ownership, and is negatively associated with slope, stand age, artificial regeneration, distance to the nearest road and fire disturbance. Our projections suggest the total area invaded will increase from 1.36 to ≈31.39% of all forestlands in Mississippi and Alabama (≈7 million hectares) and the annual frequency of crown fires in these forestlands will approximately double within the next two decades. Such time series projections of annual range expansions and crown fire frequency

  2. Connecting differential responses of native and invasive riparian plants to climate change and environmental alteration.

    PubMed

    Flanagan, Neal E; Richardson, Curtis J; Ho, Mengchi

    2015-04-01

    Climate change is predicted to impact river systems in the southeastern United States through alterations of temperature, patterns of precipitation and hydrology. Future climate scenarios for the southeastern United States predict (1) surface water temperatures will warm in concert with air temperature, (2) storm flows will increase and base flows will decrease, and (3) the annual pattern of synchronization between hydroperiod and water temperature will be altered. These alterations are expected to disturb floodplain plant communities, making them more vulnerable to establishment of invasive species. The primary objective of this study is to evaluate whether native and invasive riparian plant assemblages respond differently to alterations of climate and land use. To study the response of riparian wetlands to watershed and climate alterations, we utilized an existing natural experiment imbedded in gradients of temperature and hydrology-found among dammed and undammed rivers. We evaluated a suite of environmental variables related to water temperature, hydrology, watershed disturbance, and edaphic conditions to identify the strongest predictors of native and invasive species abundances. We found that native species abundance is strongly influenced by climate-driven variables such as temperature and hydrology, while invasive species abundance is more strongly influenced by site-specific factors such as land use and soil nutrient availability. The patterns of synchronization between plant phenology, annual hydrographs, and annual water temperature cycles may be key factors sustaining the viability of native riparian plant communities. Our results demonstrate the need to understand the interactions between climate, land use, and nutrient management in maintaining the species diversity of riparian plant communities. Future climate change is likely to result in diminished competitiveness of native plant species, while the competitiveness of invasive species will increase

  3. Connecting differential responses of native and invasive riparian plants to climate change and environmental alteration.

    PubMed

    Flanagan, Neal E; Richardson, Curtis J; Ho, Mengchi

    2015-04-01

    Climate change is predicted to impact river systems in the southeastern United States through alterations of temperature, patterns of precipitation and hydrology. Future climate scenarios for the southeastern United States predict (1) surface water temperatures will warm in concert with air temperature, (2) storm flows will increase and base flows will decrease, and (3) the annual pattern of synchronization between hydroperiod and water temperature will be altered. These alterations are expected to disturb floodplain plant communities, making them more vulnerable to establishment of invasive species. The primary objective of this study is to evaluate whether native and invasive riparian plant assemblages respond differently to alterations of climate and land use. To study the response of riparian wetlands to watershed and climate alterations, we utilized an existing natural experiment imbedded in gradients of temperature and hydrology-found among dammed and undammed rivers. We evaluated a suite of environmental variables related to water temperature, hydrology, watershed disturbance, and edaphic conditions to identify the strongest predictors of native and invasive species abundances. We found that native species abundance is strongly influenced by climate-driven variables such as temperature and hydrology, while invasive species abundance is more strongly influenced by site-specific factors such as land use and soil nutrient availability. The patterns of synchronization between plant phenology, annual hydrographs, and annual water temperature cycles may be key factors sustaining the viability of native riparian plant communities. Our results demonstrate the need to understand the interactions between climate, land use, and nutrient management in maintaining the species diversity of riparian plant communities. Future climate change is likely to result in diminished competitiveness of native plant species, while the competitiveness of invasive species will increase

  4. Range expansion of invasive shrubs: implication for crown fire risk in forestlands of the southern USA.

    PubMed

    Wang, Hsiao-Hsuan; Wonkka, Carissa L; Grant, William E; Rogers, William E

    2016-01-01

    Non-native plant invasions and changing management activities have dramatically altered the structure and composition of forests worldwide. Invasive shrubs and fire suppression have led to increased densification and biomass accumulation in forest ecosystems of the southeastern USA. Notably, Chinese and European privets are rapid growing, shade-tolerant shrubs which number among the most aggressive invasive species in these forests. Privet encroachment has caused losses of native diversity, alteration of ecosystem processes and changes in community structure. The latter has become manifest through decreases in fine herbaceous fuels concurrent with increases in coarse woody fuels in forest understoreys. These alterations in fuel structure will potentially lead to less frequent, but more severe forest fires, which threaten important forest resources during extreme weather conditions. Drawing on extensive data sets compiled by the US Forest Service, we integrated statistical forecasting and analytical techniques within a spatially explicit, agent-based, simulation framework to predict potential range expansion of Chinese and European privet (Ligustrum sinenseandL. vulgare) and the associated increase in crown fire risk over the next two decades in forestlands of Mississippi and Alabama. Our results indicate that probability of invasion is positively associated with elevation, adjacency (within 300 m) to water bodies, mean daily maximum temperature, site productivity and private land ownership, and is negatively associated with slope, stand age, artificial regeneration, distance to the nearest road and fire disturbance. Our projections suggest the total area invaded will increase from 1.36 to ≈31.39% of all forestlands in Mississippi and Alabama (≈7 million hectares) and the annual frequency of crown fires in these forestlands will approximately double within the next two decades. Such time series projections of annual range expansions and crown fire frequency

  5. Arbuscular mycorrhizal assemblages in native plant roots change in the presence of invasive exotic grasses

    USGS Publications Warehouse

    Hawkes, C.V.; Belnap, J.; D'Antonio, C.; Firestone, M.K.

    2006-01-01

    Plant invasions have the potential to significantly alter soil microbial communities, given their often considerable aboveground effects. We examined how plant invasions altered the arbuscular mycorrhizal fungi of native plant roots in a grassland site in California and one in Utah. In the California site, we used experimentally created plant communities composed of exotic (Avena barbata, Bromus hordeaceus) and native (Nassella pulchra, Lupinus bicolor) monocultures and mixtures. In the Utah semi-arid grassland, we took advantage of invasion by Bromus tectorum into long-term plots dominated by either of two native grasses, Hilaria jamesii or Stipa hymenoides. Arbuscular mycorrhizal fungi colonizing roots were characterized with PCR amplification of the ITS region, cloning, and sequencing. We saw a significant effect of the presence of exotic grasses on the diversity of mycorrhizal fungi colonizing native plant roots. In the three native grasses, richness of mycorrhizal fungi decreased; in the native forb at the California site, the number of fungal RFLP patterns increased in the presence of exotics. The exotic grasses also caused the composition of the mycorrhizal community in native roots to shift dramatically both in California, with turnover of Glomus spp., and Utah, with replacement of Glomus spp. by apparently non-mycorrhizal fungi. Invading plants may be able to influence the network of mycorrhizal fungi in soil that is available to natives through either earlier root activity or differential carbon provision compared to natives. Alteration of the soil microbial community by plant invasion can provide a mechanism for both successful invasion and the resulting effects of invaders on the ecosystem. ?? Springer 2006.

  6. Range expansion of invasive shrubs: implication for crown fire risk in forestlands of the southern USA.

    PubMed

    Wang, Hsiao-Hsuan; Wonkka, Carissa L; Grant, William E; Rogers, William E

    2016-01-01

    Non-native plant invasions and changing management activities have dramatically altered the structure and composition of forests worldwide. Invasive shrubs and fire suppression have led to increased densification and biomass accumulation in forest ecosystems of the southeastern USA. Notably, Chinese and European privets are rapid growing, shade-tolerant shrubs which number among the most aggressive invasive species in these forests. Privet encroachment has caused losses of native diversity, alteration of ecosystem processes and changes in community structure. The latter has become manifest through decreases in fine herbaceous fuels concurrent with increases in coarse woody fuels in forest understoreys. These alterations in fuel structure will potentially lead to less frequent, but more severe forest fires, which threaten important forest resources during extreme weather conditions. Drawing on extensive data sets compiled by the US Forest Service, we integrated statistical forecasting and analytical techniques within a spatially explicit, agent-based, simulation framework to predict potential range expansion of Chinese and European privet (Ligustrum sinenseandL. vulgare) and the associated increase in crown fire risk over the next two decades in forestlands of Mississippi and Alabama. Our results indicate that probability of invasion is positively associated with elevation, adjacency (within 300 m) to water bodies, mean daily maximum temperature, site productivity and private land ownership, and is negatively associated with slope, stand age, artificial regeneration, distance to the nearest road and fire disturbance. Our projections suggest the total area invaded will increase from 1.36 to ≈31.39% of all forestlands in Mississippi and Alabama (≈7 million hectares) and the annual frequency of crown fires in these forestlands will approximately double within the next two decades. Such time series projections of annual range expansions and crown fire frequency

  7. Invasive Prenatal Testing

    PubMed Central

    Hunter, A.

    1988-01-01

    Invasive prenatal diagnosis is a major diagnostic tool which is used in modern obstetrical care. A synopsis of these techniques is provided to assist the family practitioner in providing this information to his patients. PMID:21253097

  8. A global assessment of invasive plant impacts on resident species, communities and ecosystems: the interaction of impact measures, invading species' traits and environment

    PubMed Central

    Pyšek, Petr; Jarošík, Vojtěch; Hulme, Philip E; Pergl, Jan; Hejda, Martin; Schaffner, Urs; Vilà, Montserrat

    2012-01-01

    With the growing body of literature assessing the impact of invasive alien plants on resident species and ecosystems, a comprehensive assessment of the relationship between invasive species traits and environmental settings of invasion on the characteristics of impacts is needed. Based on 287 publications with 1551 individual cases that addressed the impact of 167 invasive plant species belonging to 49 families, we present the first global overview of frequencies of significant and non-significant ecological impacts and their directions on 15 outcomes related to the responses of resident populations, species, communities and ecosystems. Species and community outcomes tend to decline following invasions, especially those for plants, but the abundance and richness of the soil biota, as well as concentrations of soil nutrients and water, more often increase than decrease following invasion. Data mining tools revealed that invasive plants exert consistent significant impacts on some outcomes (survival of resident biota, activity of resident animals, resident community productivity, mineral and nutrient content in plant tissues, and fire frequency and intensity), whereas for outcomes at the community level, such as species richness, diversity and soil resources, the significance of impacts is determined by interactions between species traits and the biome invaded. The latter outcomes are most likely to be impacted by annual grasses, and by wind pollinated trees invading mediterranean or tropical biomes. One of the clearest signals in this analysis is that invasive plants are far more likely to cause significant impacts on resident plant and animal richness on islands rather than mainland. This study shows that there is no universal measure of impact and the pattern observed depends on the ecological measure examined. Although impact is strongly context dependent, some species traits, especially life form, stature and pollination syndrome, may provide a means to predict

  9. Parasites and marine invasions

    USGS Publications Warehouse

    Torchin, M.E.; Lafferty, K.D.; Kuris, A.M.

    2002-01-01

    Introduced marine species are a major environmental and economic problem. The rate of these biological invasions has substantially increased in recent years due to the globalization of the world's economies. The damage caused by invasive species is often a result of the higher densities and larger sizes they attain compared to where they are native. A prominent hypothesis explaining the success of introduced species is that they are relatively free of the effects of natural enemies. Most notably, they may encounter fewer parasites in their introduced range compared to their native range. Parasites are ubiquitous and pervasive in marine systems, yet their role in marine invasions is relatively unexplored. Although data on parasites of marine organisms exist, the extent to which parasites can mediate marine invasions, or the extent to which invasive parasites and pathogens are responsible for infecting or potentially decimating native marine species have not been examined. In this review, we present a theoretical framework to model invasion success and examine the evidence for a relationship between parasite presence and the success of introduced marine species. For this, we compare the prevalence and species richness of parasites in several introduced populations of marine species with populations where they are native. We also discuss the potential impacts of introduced marine parasites on native ecosystems.

  10. Biliopancreatic diversion.

    PubMed

    Scopinaro, N; Adami, G F; Marinari, G M; Gianetta, E; Traverso, E; Friedman, D; Camerini, G; Baschieri, G; Simonelli, A

    1998-09-01

    Biliopancreatic diversion (BPD) has made reacceptable the malabsorptive approach to the surgical treatment of obesity. The procedure, in a series of 2241 patients operated on during a 21-year period, caused a mean permanent reduction of about 75% of the initial excess weight. The indefinite weight maintenance appears to be due to the existence of a threshold absorption capacity for fat and starch, and thus energy, and the weight loss is partly due to increased resting energy expenditure. Beneficial effects other than those consequent to weight loss or reduced nutrient absorption included permanent normalization of serum glucose and cholesterol without any medication and on totally free diet in 100% of cases, both phenomena being due to a specific action of the operation. Operative mortality was less than 0.5%. Specific late complications included anemia, less than 5% with adequate iron or folate supplementation (or both); stomal ulcer, reduced to 3.2% by oral H2-blocker prophylaxis; bone demineralization, increasing up to the fourth year and tending to decrease thereafter, with need of calcium and vitamin D supplementation; neurologic complications, totally avoidable by prompt vitamin B administration to patients at risk; protein malnutrition, which was reduced to a minimum of 3% with 1.3% recurrence, in exchange with a smaller weight loss, by adapting the volume of the gastric remnant and the length of the alimentary limb to the patient's individual characteristics. It is concluded that the correct use of BPD, based on the knowledge of its mechanisms of action, can make the procedure an effective, safe one in all hands.

  11. Mixed population genomics support for the central marginal hypothesis across the invasive range of the cane toad (Rhinella marina) in Australia.

    PubMed

    Trumbo, Daryl R; Epstein, Brendan; Hohenlohe, Paul A; Alford, Ross A; Schwarzkopf, Lin; Storfer, Andrew

    2016-09-01

    Understanding factors that cause species' geographic range limits is a major focus in ecology and evolution. The central marginal hypothesis (CMH) predicts that species cannot adapt to conditions beyond current geographic range edges because genetic diversity decreases from core to edge due to smaller, more isolated edge populations. We employed a population genomics framework using 24 235-33 112 SNP loci to test major predictions of the CMH in the ongoing invasion of the cane toad (Rhinella marina) in Australia. Cane toad tissue samples were collected along broad-scale, core-to-edge transects across their invasive range. Geographic and ecological core areas were identified using GIS and habitat suitability indices from ecological niche modelling. Bayesian clustering analyses revealed three genetic clusters, in the northwest invasion-front region, northeast precipitation-limited region and southeast cold temperature-limited region. Core-to-edge patterns of genetic diversity and differentiation were consistent with the CMH in the southeast, but were not supported in the northeast and showed mixed support in the northwest. Results suggest cold temperatures are a likely contributor to southeastern range limits, consistent with CMH predictions. In the northeast and northwest, ecological processes consisting of a steep physiological barrier and ongoing invasion dynamics, respectively, are more likely explanations for population genomic patterns than the CMH. PMID:27393238

  12. MEK-dependent IL-8 induction regulates the invasiveness of triple-negative breast cancer cells.

    PubMed

    Kim, Sangmin; Lee, Jeongmin; Jeon, Myeongjin; Lee, Jeong Eon; Nam, Seok Jin

    2016-04-01

    Interleukin-8 (IL-8) serves as a prognostic marker for breast cancer, and its expression level correlates with metastatic breast cancer and poor prognosis. Here, we investigated the levels of IL-8 expression in a variety of breast cancer cells and the regulatory mechanism of IL-8 in triple-negative breast cancer (TNBC) cells. Our results showed that IL-8 expression correlated positively with overall survival in basal-type breast cancer patients. The levels of IL-8 mRNA expression and protein secretion were significantly increased in TNBC cells compared with non-TNBC cells. In addition, the invasiveness of the TNBC cells was dramatically increased by IL-8 treatment and then augmented invasion-related proteins such as matrix metalloproteinase (MMP)-2 or MMP-9. We observed that elevated IL-8 mRNA expression and protein secretion were suppressed by a specific MEK1/2 inhibitor, UO126. In contrast, the overexpression of constitutively active MEK significantly increased the level of IL-8 mRNA expression in BT474 non-TNBC cells. Finally, we investigated the effect of UO126 on the tumorigenecity of TNBC cells. Our results showed that anchorage-independent growth, cell invasion, and cell migration were also decreased by UO126 in TNBC cells. As such, we demonstrated that IL-8 expression is regulated through MEK/ERK-dependent pathways in TNBC cells. A diversity of MEK blockers, including UO126, may be promising for treating TNBC patients.

  13. Are modern biological invasions an unprecedented form of global change?

    PubMed

    Ricciardi, Anthony

    2007-04-01

    The uniqueness of the current, global mass invasion by nonindigenous species has been challenged recently by researchers who argue that modern rates and consequences of nonindigenous species establishment are comparable to episodes in the geological past. Although there is a fossil record of species invasions occurring in waves after geographic barriers had been lifted, such episodic events differ markedly from human-assisted invasions in spatial and temporal scales and in the number and diversity of organisms involved in long-distance dispersal. Today, every region of the planet is simultaneously affected and modern rates of invasion are several orders of magnitude higher than prehistoric rates. In terms of its rate and geographical extent, its potential for synergistic disruption and the scope of its evolutionary consequences, the current mass invasion event is without precedent and should be regarded as a unique form of global change. Prehistoric examples of biotic interchanges are nonetheless instructive and can increase our understanding of species-area effects, evolutionary effects, biotic resistance to invasion, and the impacts of novel functional groups introduced to naïve biotas. Nevertheless, they provide only limited insight into the synergistic effects of invasions and other environmental stressors, the effect of frequent introductions of large numbers of propagules, and global homogenization, all of which characterize the current mass invasion event. PMID:17391183

  14. Minimally invasive procedures

    PubMed Central

    Baltayiannis, Nikolaos; Michail, Chandrinos; Lazaridis, George; Anagnostopoulos, Dimitrios; Baka, Sofia; Mpoukovinas, Ioannis; Karavasilis, Vasilis; Lampaki, Sofia; Papaiwannou, Antonis; Karavergou, Anastasia; Kioumis, Ioannis; Pitsiou, Georgia; Katsikogiannis, Nikolaos; Tsakiridis, Kosmas; Rapti, Aggeliki; Trakada, Georgia; Zissimopoulos, Athanasios; Zarogoulidis, Konstantinos

    2015-01-01

    Minimally invasive procedures, which include laparoscopic surgery, use state-of-the-art technology to reduce the damage to human tissue when performing surgery. Minimally invasive procedures require small “ports” from which the surgeon inserts thin tubes called trocars. Carbon dioxide gas may be used to inflate the area, creating a space between the internal organs and the skin. Then a miniature camera (usually a laparoscope or endoscope) is placed through one of the trocars so the surgical team can view the procedure as a magnified image on video monitors in the operating room. Specialized equipment is inserted through the trocars based on the type of surgery. There are some advanced minimally invasive surgical procedures that can be performed almost exclusively through a single point of entry—meaning only one small incision, like the “uniport” video-assisted thoracoscopic surgery (VATS). Not only do these procedures usually provide equivalent outcomes to traditional “open” surgery (which sometimes require a large incision), but minimally invasive procedures (using small incisions) may offer significant benefits as well: (I) faster recovery; (II) the patient remains for less days hospitalized; (III) less scarring and (IV) less pain. In our current mini review we will present the minimally invasive procedures for thoracic surgery. PMID:25861610

  15. Minimally invasive pancreatic surgery.

    PubMed

    Yiannakopoulou, E

    2015-12-01

    Minimally invasive pancreatic surgery is feasible and safe. Laparoscopic distal pancreatectomy should be widely adopted for benign lesions of the pancreas. Laparoscopic pancreaticoduodenectomy, although technically demanding, in the setting of pancreatic ductal adenocarcinoma has a number of advantages including shorter hospital stay, faster recovery, allowing patients to recover in a timelier manner and pursue adjuvant treatment options. Furthermore, it seems that progression-free survival is longer in patients undergoing laparoscopic pancreaticoduodenectomy in comparison with those undergoing open pancreaticoduodenectomy. Minimally invasive middle pancreatectomy seems appropriate for benign or borderline tumors of the neck of the pancreas. Technological advances including intraoperative ultrasound and intraoperative fluorescence imaging systems are expected to facilitate the wide adoption of minimally invasive pancreatic surgery. Although, the oncological outcome seems similar with that of open surgery, there are still concerns, as the majority of relevant evidence comes from retrospective studies. Large multicenter randomized studies comparing laparoscopic with open pancreatectomy as well as robotic assisted with both open and laparoscopic approaches are needed. Robotic approach could be possibly shown to be less invasive than conventional laparoscopic approach through the less traumatic intra-abdominal handling of tissues. In addition, robotic approach could enable the wide adoption of the technique by surgeon who is not that trained in advanced laparoscopic surgery. A putative clinical benefit of minimally invasive pancreatic surgery could be the attenuated surgical stress response leading to reduced morbidity and mortality as well as lack of the detrimental immunosuppressive effect especially for the oncological patients. PMID:26530291

  16. Alien invasive birds.

    PubMed

    Brochier, B; Vangeluwe, D; van den Berg, T

    2010-08-01

    A bird species is regarded as alien invasive if it has been introduced, intentionally or accidentally, to a location where it did not previously occur naturally, becomes capable of establishing a breeding population without further intervention by humans, spreads and becomes a pest affecting the environment, the local biodiversity, the economy and/or society, including human health. European Starling (Sturnus vulgaris), Common Myna (Acridotheres tristis) and Red-vented Bulbul (Pycnonotus cafer) have been included on the list of '100 of the World's Worst Invasive Alien Species', a subset of the Global Invasive Species Database. The 'Delivering Alien Invasive Species Inventories for Europe' project has selected Canada Goose (Branta canadensis), Ruddy Duck (Oxyura jamaicensis), Rose-ringed Parakeet (Psittacula krameri) and Sacred Ibis (Threskiornis aethiopicus) as among 100 of the worst invasive species in Europe. For each of these alien bird species, the geographic range (native and introduced range), the introduction pathway, the general impacts and the management methods are presented. PMID:20919578

  17. 76 FR 18575 - Nominations of New Members to the Invasive Species Advisory Committee (ISAC)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-04-04

    ... international cooperation in addressing invasive species; facilitates the development of a coordinated network... issues. ISAC provides advice in cooperation with stakeholders and existing organizations addressing...; coordinating diverse groups of stakeholders to resolve complex environmental issues and conflicts;...

  18. Over-invasion by functionally equivalent invasive species.

    PubMed

    Russell, James C; Sataruddin, Nurul S; Heard, Allison D

    2014-08-01

    Multiple invasive species have now established at most locations around the world, and the rate of new species invasions and records of new invasive species continue to grow. Multiple invasive species interact in complex and unpredictable ways, altering their invasion success and impacts on biodiversity. Incumbent invasive species can be replaced by functionally similar invading species through competitive processes; however the generalized circumstances leading to such competitive displacement have not been well investigated. The likelihood of competitive displacement is a function of the incumbent advantage of the resident invasive species and the propagule pressure of the colonizing invasive species. We modeled interactions between populations of two functionally similar invasive species and indicated the circumstances under which dominance can be through propagule pressure and incumbent advantage. Under certain circumstances, a normally subordinate species can be incumbent and reject a colonizing dominant species, or successfully colonize in competition with a dominant species during simultaneous invasion. Our theoretical results are supported by empirical studies of the invasion of islands by three invasive Rattus species. Competitive displacement is prominent in invasive rats and explains the replacement of R. exulans on islands subsequently invaded by European populations of R. rattus and R. norvegicus. These competition outcomes between invasive species can be found in a broad range of taxa and biomes, and are likely to become more common. Conservation management must consider that removing an incumbent invasive species may facilitate invasion by another invasive species. Under very restricted circumstances of dominant competitive ability but lesser impact, competitive displacement may provide a novel method of biological control.

  19. Theme: Supporting Professional Diversity.

    ERIC Educational Resources Information Center

    Moore, Eddie A.; And Others

    1994-01-01

    Includes "Supporting Diversity" (Moore); "Reflections on the Need for Diversity" (Bowen); "Understanding Impediments to Diversity in Agricultural Education" (Whent); "Mentoring Diverse Populations" (Jones); "Supporting Diversity: An Unfinished Agenda" (Moore); "Professorial Roles in Supporting Diversity in Teaching, Research, and University…

  20. Exotic weevil invasion increases floral herbivore community density, function, and impact on a native plant

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Consumer communities are being re-arranged through unprecedented rates of human-mediated invasions and extinctions. Such changes in consumer composition and diversity potentially alter pressure and impact on resource populations. Although insect herbivore invasions are common, and exotic herbivores...

  1. Climate change, plant traits, and invasion in natural and agricultural ecosystems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive species and climate change, each of which is likely to influence agricultural productivity and biological diversity, are also likely to interact. This chapter explores characteristics of both invasive plants and invaded ecosystems to search for generalizations that may allow us to predict w...

  2. Minimally invasive procedures on the lumbar spine

    PubMed Central

    Skovrlj, Branko; Gilligan, Jeffrey; Cutler, Holt S; Qureshi, Sheeraz A

    2015-01-01

    Degenerative disease of the lumbar spine is a common and increasingly prevalent condition that is often implicated as the primary reason for chronic low back pain and the leading cause of disability in the western world. Surgical management of lumbar degenerative disease has historically been approached by way of open surgical procedures aimed at decompressing and/or stabilizing the lumbar spine. Advances in technology and surgical instrumentation have led to minimally invasive surgical techniques being developed and increasingly used in the treatment of lumbar degenerative disease. Compared to the traditional open spine surgery, minimally invasive techniques require smaller incisions and decrease approach-related morbidity by avoiding muscle crush injury by self-retaining retractors, preventing the disruption of tendon attachment sites of important muscles at the spinous processes, using known anatomic neurovascular and muscle planes, and minimizing collateral soft-tissue injury by limiting the width of the surgical corridor. The theoretical benefits of minimally invasive surgery over traditional open surgery include reduced blood loss, decreased postoperative pain and narcotics use, shorter hospital length of stay, faster recover and quicker return to work and normal activity. This paper describes the different minimally invasive techniques that are currently available for the treatment of degenerative disease of the lumbar spine. PMID:25610845

  3. The importance of education in managing invasive plant species

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive plant species can establish in diverse environments and with the increase in human mobility, they are no longer restricted to isolated pockets in remote parts of the world. Cheat grass (Bromus tectorum L.) in rangelands, purple loosestrife (Lythrum salicaria L.) in wet lands and Canada this...

  4. Precambrian columnar stromatolite diversity: reflection of metazoan appearance.

    PubMed

    Awramik, S M

    1971-11-19

    Columnar stromatolites (organosedimentary structures built by bluegreen algae) show a marked decrease in diversity in the Late Precambrian; this decrease in diversity occurs at approximately the same time as the appearance of metazoans, 600 to 700 million years ago.

  5. Early Primary Invasion Scientists

    ERIC Educational Resources Information Center

    Spellman, Katie V.; Villano, Christine P.

    2011-01-01

    "We really need to get the government involved," said one student, holding his graph up to USDA scientist Steve Seefeldt. Dr. Steve studies methods to control "invasive" plants, plants that have been introduced to an area by humans and have potential to spread rapidly and negatively affect ecosystems. The first grader and his classmates had become…

  6. Aquatic invasive species

    USGS Publications Warehouse

    Thorsteinson, Lyman

    2005-01-01

    Invasive species are plants or animals that are present in an ecosystem beyond their native range. They may have few natural controls in their new environment and proliferate. They can threaten native species and interfere with human activities. The Western Fisheries Research Center (WFRC) has been conducting research to understand how non-native species invade and affect ecosystems, thus aiding management efforts.

  7. Constraints on coastal dune invasion for a notorious plant invader.

    PubMed

    Griffith, Alden B; Ahmed, Tania; Hildner, Abigail L G; Kuckreja, Shivani; Long, Shuangxou

    2015-11-10

    Although most biological invasions are not successful, relatively few studies have examined otherwise notorious invaders in systems where they are not highly problematic. The annual grass Bromus tectorum is a dominant invader in western North America, but is usually confined to human-dominated and disturbed systems (e.g. roadsides and parking lots) in the East where it remains virtually unstudied. This study aims to address fundamental ecological questions regarding B. tectorum in a Cape Cod dune ecosystem. (i) What is the range of variation in population dynamics and the potential for population growth? (ii) Which factors influence its local abundance and distribution? We observed substantial variation in population dynamics over 3 years, with the number of adult B. tectorum individuals increasing substantially between the first 2 years (λ = 9.24) and then decreasing (λ = 0.43). Population growth in terms of total seeds was similarly variable, but to a lesser extent (λ = 2.32 followed by λ = 0.32). Experimental soil disturbance led to a more than 10-fold increase in mean seedling emergence, and high sensitivity to differences in emergence carried this effect through the life cycle. In contrast, barriers to seed dispersal had no effect on population dynamics, suggesting limited dispersal in this system. Across the landscape, the presence of B. tectorum was associated with areas of higher plant diversity as opposed to those with a strong dominant (e.g. the foredune, dominated by Ammophila breviligulata, or low heathlands, characterized by Hudsonia tomentosa and Arctostaphylos uva-ursi). Overall, we find that B. tectorum is capable of both substantial population growth and decline in a dune ecosystem, but is likely limited without disturbance and dispersal agents. Thus, management actions that restrict dune access (e.g. for nesting habitat) likely have the co-benefit of limiting the invasive potential of B. tectorum.

  8. Constraints on coastal dune invasion for a notorious plant invader

    PubMed Central

    Griffith, Alden B.; Ahmed, Tania; Hildner, Abigail L. G.; Kuckreja, Shivani; Long, Shuangxou

    2015-01-01

    Although most biological invasions are not successful, relatively few studies have examined otherwise notorious invaders in systems where they are not highly problematic. The annual grass Bromus tectorum is a dominant invader in western North America, but is usually confined to human-dominated and disturbed systems (e.g. roadsides and parking lots) in the East where it remains virtually unstudied. This study aims to address fundamental ecological questions regarding B. tectorum in a Cape Cod dune ecosystem. (i) What is the range of variation in population dynamics and the potential for population growth? (ii) Which factors influence its local abundance and distribution? We observed substantial variation in population dynamics over 3 years, with the number of adult B. tectorum individuals increasing substantially between the first 2 years (λ = 9.24) and then decreasing (λ = 0.43). Population growth in terms of total seeds was similarly variable, but to a lesser extent (λ = 2.32 followed by λ = 0.32). Experimental soil disturbance led to a more than 10-fold increase in mean seedling emergence, and high sensitivity to differences in emergence carried this effect through the life cycle. In contrast, barriers to seed dispersal had no effect on population dynamics, suggesting limited dispersal in this system. Across the landscape, the presence of B. tectorum was associated with areas of higher plant diversity as opposed to those with a strong dominant (e.g. the foredune, dominated by Ammophila breviligulata, or low heathlands, characterized by Hudsonia tomentosa and Arctostaphylos uva-ursi). Overall, we find that B. tectorum is capable of both substantial population growth and decline in a dune ecosystem, but is likely limited without disturbance and dispersal agents. Thus, management actions that restrict dune access (e.g. for nesting habitat) likely have the co-benefit of limiting the invasive potential of B. tectorum. PMID:26558705

  9. Landscape determinants of nonindigenous fish invasions

    USGS Publications Warehouse

    Ross, R.M.; Lellis, W.A.; Bennett, R.M.; Johnson, C.S.

    2001-01-01

    Much has been written about the influence of exotic or nonindigenous species on natural habitats and communities of organisms, but little is known of the physical or biological conditions that lead to successful invasion of native habitats and communities by exotics. We studied invasivity factors in headwater streams of the Susquehanna River West Branch, which drains portions of the northern Appalachian Plateau. A replicated (two major tributaries) 3 ?? 3 factorial design was used to determine landscape effects of size (stream order) and quality (land use) on abiotic (physical and chemical) and biotic (fish community structure and function) stream attributes. Seven (21%) of thirty-four fish species (brown trout, common carp, mimic shiner, bluegill, smallmouth bass, fantail darter, and banded darter) collected in the eighteen streams sampled were nonindigenous to the basin. Watershed size (stream orders 1, 3, and 5) significantly affected stream geomorphologic and habitat variables (gradient, width, depth, current velocity, diel water temperature, bank overhang, canopy cover, and woody debris density) but not water-quality variables, while land use in watersheds (conservation, mining, and agriculture) significantly affected measured water-quality variables (alkalinity and concentrations of manganese, calcium, chloride, nitrate, and total dissolved solids) but not stream physical or habitat quality. Both watershed size and land use affected fish-community variables such as presence of particular species, species density, species diversity, tolerance diversity, and mean fish size, but in both cases the effect was transparent to native-origin status of fish species. No relationships were found between occurrence of nonindigenous species in watersheds and trophic structure or functional diversity. Therefore, the hypothesis that reduced species diversity increases vulnerability to nonindigenous species was not supported. However, the spatial variation associated with

  10. What determines positive, neutral, and negative impacts of Solidago canadensis invasion on native plant species richness?

    PubMed

    Dong, Li-Jia; Yu, Hong-Wei; He, Wei-Ming

    2015-11-17

    Whether plant invasions pose a great threat to native plant diversity is still hotly debated due to conflicting findings. More importantly, we know little about the mechanisms of invasion impacts on native plant richness. We examined how Solidago canadensis invasion influenced native plants using data from 291 pairs of invaded and uninvaded plots covering an entire invaded range, and quantified the relative contributions of climate, recipient communities, and S. canadensis to invasion impacts. There were three types of invasion consequences for native plant species richness (i.e., positive, neutral, and negative impacts). Overall, the relative contributions of recipient communities, S. canadensis and climate to invasion impacts were 71.39%, 21.46% and 7.15%, respectively; furthermore, the roles of recipient communities, S. canadensis and climate were largely ascribed to plant diversity, density and cover, and precipitation. In terms of direct effects, invasion impacts were negatively linked to temperature and native plant communities, and positively to precipitation and soil microbes. Soil microbes were crucial in the network of indirect effects on invasion impacts. These findings suggest that the characteristics of recipient communities are the most important determinants of invasion impacts and that invasion impacts may be a continuum across an entire invaded range.

  11. What determines positive, neutral, and negative impacts of Solidago canadensis invasion on native plant species richness?

    PubMed Central

    Dong, Li-Jia; Yu, Hong-Wei; He, Wei-Ming

    2015-01-01

    Whether plant invasions pose a great threat to native plant diversity is still hotly debated due to conflicting findings. More importantly, we know little about the mechanisms of invasion impacts on native plant richness. We examined how Solidago canadensis invasion influenced native plants using data from 291 pairs of invaded and uninvaded plots covering an entire invaded range, and quantified the relative contributions of climate, recipient communities, and S. canadensis to invasion impacts. There were three types of invasion consequences for native plant species richness (i.e., positive, neutral, and negative impacts). Overall, the relative contributions of recipient communities, S. canadensis and climate to invasion impacts were 71.39%, 21.46% and 7.15%, respectively; furthermore, the roles of recipient communities, S. canadensis and climate were largely ascribed to plant diversity, density and cover, and precipitation. In terms of direct effects, invasion impacts were negatively linked to temperature and native plant communities, and positively to precipitation and soil microbes. Soil microbes were crucial in the network of indirect effects on invasion impacts. These findings suggest that the characteristics of recipient communities are the most important determinants of invasion impacts and that invasion impacts may be a continuum across an entire invaded range. PMID:26573017

  12. Minimally Invasive Mitral Valve Procedures: The Current State

    PubMed Central

    Ritwick, Bhuyan; Chaudhuri, Krishanu; Crouch, Gareth; Edwards, James R. M.; Worthington, Michael; Stuklis, Robert G.

    2013-01-01

    Since its early days, cardiac surgery has typically involved large incisions with complete access to the heart and the great vessels. After the popularization of the minimally invasive techniques in general surgery, cardiac surgeons began to experiment with minimal access techniques in the early 1990s. Although the goals of minimally invasive cardiac surgery (MICS) are fairly well established as decreased pain, shorter hospital stay, accelerated recuperation, improved cosmesis, and cost effectiveness, a strict definition of minimally invasive cardiac surgery has been more elusive. Minimally invasive cardiac surgery started with mitral valve procedures and then gradually expanded towards other valve procedures, coronary artery bypass grafting, and various types of simple congenital heart procedures. In this paper, the authors attempt to focus on the evolution, techniques, results, and the future perspective of minimally invasive mitral valve surgery (MIMVS). PMID:24382998

  13. Shikonin inhibits invasiveness of osteosarcoma through MMP13 suppression.

    PubMed

    Deng, Biyong; Qiu, Bing

    2015-12-01

    Osteosarcoma (OS) is the most common primary malignant bone tumor, notorious for its metastasis. We have recently shown that shikonin, an effective constituent extracted from Chinese medicinal herb, induces necroptosis in OS cells. Nevertheless, the effects of low-dose shikonin on the invasiveness of OS cells are unknown. Here, we showed that shikonin dose-dependently decreased OS cell invasiveness in both scratch wound healing assay and transwell cell migration assay. Moreover, the direct target of shikonin on cell invasiveness was found to be matrix metalloproteinase (MMP)-13. Further, the inhibitory effects of shikonin on cell invasiveness were completely abolished in MMP13-overexpressing OS cells. Together, these data suggest that shikonin may suppress OS invasiveness through MMP13 suppression. Thus, our data highlight a previous unappreciated role for shikonin in suppressing OS cell metastasis. PMID:26104765

  14. Placing invasive species management in a spatiotemporal context.

    PubMed

    Baker, Christopher M; Bode, Michael

    2016-04-01

    Invasive species are a worldwide issue, both ecologically and economically. A large body of work focuses on various aspects of invasive species control, including how to allocate control efforts to eradicate an invasive population as cost effectively as possible: There are a diverse range of invasive species management problems, and past mathematical analyses generally focus on isolated examples, making it hard to identify and understand parallels between the different contexts. In this study, we use a single spatiotemporal model to tackle the problem of allocating control effort for invasive species when suppressing an island invasive species, and for long-term spatial suppression projects. Using feral cat suppression as an illustrative example, we identify the optimal resource allocation for island and mainland suppression projects. Our results demonstrate how using a single model to solve different problems reveals similar characteristics of the solutions in different scenarios. As well as illustrating the insights offered by linking problems through a spatiotemporal model, we also derive novel and practically applicable results for our case studies. For temporal suppression projects on islands, we find that lengthy projects are more cost effective and that rapid control projects are only economically cost effective when population growth rates are high or diminishing returns on control effort are low. When suppressing invasive species around conservation assets (e.g., national parks or exclusion fences), we find that the size of buffer zones should depend on the ratio of the species growth and spread rate.

  15. Placing invasive species management in a spatiotemporal context.

    PubMed

    Baker, Christopher M; Bode, Michael

    2016-04-01

    Invasive species are a worldwide issue, both ecologically and economically. A large body of work focuses on various aspects of invasive species control, including how to allocate control efforts to eradicate an invasive population as cost effectively as possible: There are a diverse range of invasive species management problems, and past mathematical analyses generally focus on isolated examples, making it hard to identify and understand parallels between the different contexts. In this study, we use a single spatiotemporal model to tackle the problem of allocating control effort for invasive species when suppressing an island invasive species, and for long-term spatial suppression projects. Using feral cat suppression as an illustrative example, we identify the optimal resource allocation for island and mainland suppression projects. Our results demonstrate how using a single model to solve different problems reveals similar characteristics of the solutions in different scenarios. As well as illustrating the insights offered by linking problems through a spatiotemporal model, we also derive novel and practically applicable results for our case studies. For temporal suppression projects on islands, we find that lengthy projects are more cost effective and that rapid control projects are only economically cost effective when population growth rates are high or diminishing returns on control effort are low. When suppressing invasive species around conservation assets (e.g., national parks or exclusion fences), we find that the size of buffer zones should depend on the ratio of the species growth and spread rate. PMID:27411245

  16. Microvascular invasion in hepatocellular carcinoma

    PubMed Central

    Ünal, Emre; İdilman, İlkay Sedakat; Akata, Deniz; Özmen, Mustafa Nasuh; Karçaaltıncaba, Muşturay

    2016-01-01

    Microvascular invasion is a crucial histopathologic prognostic factor for hepatocellular carcinoma. We reviewed the literature and aimed to draw attention to clinicopathologic and imaging findings that may predict the presence of microvascular invasion in hepatocellular carcinoma. Imaging findings suggesting microvascular invasion are disruption of capsule, irregular tumor margin, peritumoral enhancement, multifocal tumor, increased tumor size, and increased glucose metabolism on positron emission tomography-computed tomography. In the presence of typical findings, microvascular invasion may be predicted. PMID:26782155

  17. [Pathogenesis of invasive fungal infections].

    PubMed

    Garcia-Vidal, Carolina; Carratalà, Jordi

    2012-03-01

    Invasive fungal infections remain a life-threatening disease. The development of invasive fungal disease is dependent on multiple factors, such us colonization and efficient host immune response. We aimed to review the pathogenesis of invasive fungal infections, in particular, those caused by Candida and Aspergillus. For this we propose, to describe the fungal characteristics, to detail the host defence mechanisms against fungus and to analyse the host risk factors for invasive fungal infection.

  18. Keystone predators (eastern newts, Notophthalmus viridescens) reduce the impacts of an aquatic invasive species

    USGS Publications Warehouse

    Smith, Kimberly G.

    2006-01-01

    Predation, competition, and their interaction are known to be important factors that influence the structure of ecological communities. In particular, in those cases where a competitive hierarchy exists among prey species, the presence of certain keystone predators can result in enhanced diversity in the prey community. However, little is known regarding the influence of keystone predator presence on invaded prey communities. Given the widespread occurrence of invasive species and substantial concern regarding their ecological impacts, studies on this topic are needed. In this study I used naturalistic replications of an experimental tadpole assemblage to assess the influence of predatory eastern newts, Notophthalmus viridescens, on the outcome of interspecific competition among native and nonindigenous tadpoles. When newts were absent, the presence of the tadpoles of one invasive species, the Cuban treefrog, Osteopilus septentrionalis, resulted in decreased survival and growth rate of the dominant native species, Bufo terrestris, and dominance of the tadpole assemblage by O. septentrionalis. However, the presence of one adult newt generally reduced or eliminated the negative impacts of O. septentrionalis tadpoles, resulting in comparable survival and performance of native species in invaded and noninvaded treatments. Differential mortality among the tadpole species suggests that newts preyed selectively on O. septentrionalis tadpoles, supporting the hypothesis that newts acted as keystone predators in the invaded assemblage. The presence of nonindigenous larval cane toads, Bufo marinus, did not significantly affect native species, and this species was not negatively affected by the presence of newts. Collectively, these results suggest that eastern newts significantly modified the competitive hierarchy of the invaded tadpole assemblage and reduced the impacts of a competitively superior invasive species. If general, these results suggest that the presence of

  19. Keystone predators (eastern newts, Notophthalmus viridescens) reduce the impacts of an aquatic invasive species.

    PubMed

    Smith, Kevin G

    2006-06-01

    Predation, competition, and their interaction are known to be important factors that influence the structure of ecological communities. In particular, in those cases where a competitive hierarchy exists among prey species, the presence of certain keystone predators can result in enhanced diversity in the prey community. However, little is known regarding the influence of keystone predator presence on invaded prey communities. Given the widespread occurrence of invasive species and substantial concern regarding their ecological impacts, studies on this topic are needed. In this study I used naturalistic replications of an experimental tadpole assemblage to assess the influence of predatory eastern newts, Notophthalmus viridescens, on the outcome of interspecific competition among native and nonindigenous tadpoles. When newts were absent, the presence of the tadpoles of one invasive species, the Cuban treefrog, Osteopilus septentrionalis, resulted in decreased survival and growth rate of the dominant native species, Bufo terrestris, and dominance of the tadpole assemblage by O. septentrionalis. However, the presence of one adult newt generally reduced or eliminated the negative impacts of O. septentrionalis tadpoles, resulting in comparable survival and performance of native species in invaded and noninvaded treatments. Differential mortality among the tadpole species suggests that newts preyed selectively on O. septentrionalis tadpoles, supporting the hypothesis that newts acted as keystone predators in the invaded assemblage. The presence of nonindigenous larval cane toads, Bufo marinus, did not significantly affect native species, and this species was not negatively affected by the presence of newts. Collectively, these results suggest that eastern newts significantly modified the competitive hierarchy of the invaded tadpole assemblage and reduced the impacts of a competitively superior invasive species. If general, these results suggest that the presence of

  20. Extracellular Matrix Invasion in Metastases and Angiogenesis: Commentary on the Matrigel "Chemoinvasion Assay".

    PubMed

    Albini, Adriana

    2016-08-15

    Invasive and metastatic cells must cross the basement membrane's extracellular matrix to disseminate to distant sites. Although in the eighties the concept was well established, no easy in vitro functional assay was available. Working in Hynda Kleinman's and George Martin's laboratory at NIH (Bethesda, MD), where the reconstituted basement membrane Matrigel was discovered, I had the intuition that Matrigel coating of migration filters could represent a valid tool to mimic in vitro biological matrix barriers. The "chemoinvasion assay" using Matrigel in Boyden blind-well chambers was developed in 1985-1986 and published in Cancer Research in 1987. It was a rapid and easy tool for studying invasion, a crucial step in cancer metastasis. Since its conception, the assay has been employed for studies on the metastatic process, angiogenesis, and for the screening of drugs that are potentially able to decrease cell invasion. It was adapted to be easily employed as a routine assay and commercialized. In that historical article, we also described the use of thick layers of Matrigel for the study of morphogenesis of invasive cells, a simple and visual assay, adaptable to reproduce collective cell migration in vitro To date, in its diverse optimized variants, the chemoinvasion assay is still widely used, contributing to novel data production. In the era of precision medicine and next-generation sequencing, the cheap, fast, and reproducible chemoinvasion assay may have further developments, including possible applications in the investigations on cancer stem cells, immunity and immune modulators, applications with siRNA silencing, selection of aggressive cell populations, and phenotypes and genetic evaluations. Cancer Res; 76(16); 4595-7. ©2016 AACR.See related article by Albini A et al., Cancer Res 1987;47:3239-45Visit the Cancer Research 75(th) Anniversary timeline.

  1. Importance of molehill disturbances for invasion by Bunias orientalis in meadows and pastures

    NASA Astrophysics Data System (ADS)

    Kiełtyk, Piotr; Mirek, Zbigniew

    2015-04-01

    Small-scale soil disturbances by fossorial animals can change physical and biotic conditions in disturbed patches and influence spatial and temporal dynamics, and the composition of plant communities. They create regeneration niches and colonization openings for native plants and, according to the intermediate disturbance hypothesis, they are expected to increase plant community diversity. However, it also has been reported that increased disturbance resource availability and decreased competition with native species may result in the invasion of communities by alien plant species, as predicted by the fluctuating resources theory of invasibility. In this study, we investigated the importance of European mole disturbances for the invasion of semi-natural fresh meadows and pastures by the alien plant, Bunias orientalis, which has mainly spread throughout Central Europe on anthropogenically disturbed sites. We hypothesized that the invader, being particularly well adapted to anthropogenic disturbances, enters into dense vegetation of meadows and pastures mainly on mole mounds. To assess the seedling recruitment of B. orientalis in relation to disturbance, we counted the number of seedlings that emerged on molehills and control plots in meadows and pastures. The establishment of juvenile (0-1 year) rosette plants on and off molehills was surveyed on 5 × 5 m plots. In accordance with our hypothesis, mole disturbances were found to serve as a gateway for B. orientalis by which the invader may colonize semi-natural grasslands. The seedlings of the species emerged almost solely on molehills and the young rosettes were established predominantly on mole mounds. Although the seedling density did not differ significantly between the meadows and pastures, the number of established plants in the pastures was considerably higher. We suggest that the invasion by B. orientalis in pastures may be facilitated by vegetative regeneration following root fragmentation by sheep pasturing.

  2. Comparing the ecological impacts of native and invasive crayfish: could native species' translocation do more harm than good?

    PubMed

    James, J; Slater, F M; Vaughan, I P; Young, K A; Cable, J

    2015-05-01

    Biological invasions are a principal threat to global biodiversity. Omnivores, such as crayfish, are among the most important groups of invaders. Their introduction often results in biodiversity loss, particularly of their native counterparts. Managed relocations of native crayfish from areas under threat from invasive crayfish into isolated 'ark sites' are sometimes suggested as a conservation strategy for native crayfish; however, such relocations may have unintended detrimental consequences for the recipient ecosystem. Despite this, there have been few attempts to quantify the relative impacts of native and invasive crayfish on aquatic ecosystems. To address this deficiency we conducted a meta-analysis on the effects of native and invasive crayfish on nine ecosystem components: decomposition rate, primary productivity, plant biomass, invertebrate density, biomass and diversity, fish biomass and refuge use, and amphibian larval survival. Native and invasive crayfish significantly reduced invertebrate density and biomass, fish biomass and amphibian survival rate and significantly increased decomposition rates. Invasive crayfish also significantly reduced plant biomass and invertebrate diversity and increased primary productivity. These results show that native and invasive crayfish have wide-ranging impacts on aquatic ecosystems that may be exacerbated for invasive species. Subsequent analysis showed that the impacts of invasive crayfish were significantly greater, in comparison to native crayfish, for decomposition and primary productivity but not invertebrate density, biomass and diversity. Overall, our findings reconfirm the ecosystem altering abilities of both native and invasive crayfish, enforcing the need to carefully regulate managed relocations of native species as well as to develop control programs for invasives. PMID:25549809

  3. Comparing the ecological impacts of native and invasive crayfish: could native species' translocation do more harm than good?

    PubMed

    James, J; Slater, F M; Vaughan, I P; Young, K A; Cable, J

    2015-05-01

    Biological invasions are a principal threat to global biodiversity. Omnivores, such as crayfish, are among the most important groups of invaders. Their introduction often results in biodiversity loss, particularly of their native counterparts. Managed relocations of native crayfish from areas under threat from invasive crayfish into isolated 'ark sites' are sometimes suggested as a conservation strategy for native crayfish; however, such relocations may have unintended detrimental consequences for the recipient ecosystem. Despite this, there have been few attempts to quantify the relative impacts of native and invasive crayfish on aquatic ecosystems. To address this deficiency we conducted a meta-analysis on the effects of native and invasive crayfish on nine ecosystem components: decomposition rate, primary productivity, plant biomass, invertebrate density, biomass and diversity, fish biomass and refuge use, and amphibian larval survival. Native and invasive crayfish significantly reduced invertebrate density and biomass, fish biomass and amphibian survival rate and significantly increased decomposition rates. Invasive crayfish also significantly reduced plant biomass and invertebrate diversity and increased primary productivity. These results show that native and invasive crayfish have wide-ranging impacts on aquatic ecosystems that may be exacerbated for invasive species. Subsequent analysis showed that the impacts of invasive crayfish were significantly greater, in comparison to native crayfish, for decomposition and primary productivity but not invertebrate density, biomass and diversity. Overall, our findings reconfirm the ecosystem altering abilities of both native and invasive crayfish, enforcing the need to carefully regulate managed relocations of native species as well as to develop control programs for invasives.

  4. Invasive species and climate change

    USGS Publications Warehouse

    Middleton, Beth A.

    2006-01-01

    Invasive species challenge managers in their work of conserving and managing natural areas and are one of the most serious problems these managers face. Because invasive species are likely to spread in response to changes in climate, managers may need to change their approaches to invasive species management accordingly.

  5. Generational diversity.

    PubMed

    Kramer, Linda W

    2010-01-01

    Generational diversity has proven challenges for nurse leaders, and generational values may influence ideas about work and career planning. This article discusses generational gaps, influencing factors and support, and the various generational groups present in today's workplace as well as the consequences of need addressing these issues. The article ends with a discussion of possible solutions.

  6. Generational diversity.

    PubMed

    Kramer, Linda W

    2010-01-01

    Generational diversity has proven challenges for nurse leaders, and generational values may influence ideas about work and career planning. This article discusses generational gaps, influencing factors and support, and the various generational groups present in today's workplace as well as the consequences of need addressing these issues. The article ends with a discussion of possible solutions. PMID:20395729

  7. Diversity Trailblazer

    ERIC Educational Resources Information Center

    Stuart, Reginald

    2012-01-01

    When Dr. Kumea Shorter-Gooden took on her newly created job this month at the University of Maryland's flagship College Park campus, she assumed a challenge at the school with a lot riding on her shoulders--helping the University of Maryland strengthen its diversity efforts and, thus, its relevance to the state in the future and standing among the…

  8. PLANT DIVERSITY

    EPA Science Inventory

    Habitat change statistics and species-area curves were used to estimate the effects of alternative future scenarios for agriculture on plant diversity in Iowa farmlands. Study areas were two watersheds in central Iowa of about 50 and 90 square kilometers, respectively. Future s...

  9. USGS invasive species solutions

    USGS Publications Warehouse

    Simpson, Annie

    2011-01-01

    Land managers must meet the invasive species challenge every day, starting with identification of problem species, then the collection of best practices for their control, and finally the implementation of a plan to remove the problem. At each step of the process, the availability of reliable information is essential to success. The U.S. Geological Survey (USGS) has developed a suite of resources for early detection and rapid response, along with data management and sharing.

  10. Minimally invasive periodontal therapy.

    PubMed

    Dannan, Aous

    2011-10-01

    Minimally invasive dentistry is a concept that preserves dentition and supporting structures. However, minimally invasive procedures in periodontal treatment are supposed to be limited within periodontal surgery, the aim of which is to represent alternative approaches developed to allow less extensive manipulation of surrounding tissues than conventional procedures, while accomplishing the same objectives. In this review, the concept of minimally invasive periodontal surgery (MIPS) is firstly explained. An electronic search for all studies regarding efficacy and effectiveness of MIPS between 2001 and 2009 was conducted. For this purpose, suitable key words from Medical Subject Headings on PubMed were used to extract the required studies. All studies are demonstrated and important results are concluded. Preliminary data from case cohorts and from many studies reveal that the microsurgical access flap, in terms of MIPS, has a high potential to seal the healing wound from the contaminated oral environment by achieving and maintaining primary closure. Soft tissues are mostly preserved and minimal gingival recession is observed, an important feature to meet the demands of the patient and the clinician in the esthetic zone. However, although the potential efficacy of MIPS in the treatment of deep intrabony defects has been proved, larger studies are required to confirm and extend the reported positive preliminary outcomes.

  11. Minimally Invasive Transforaminal Lumbar Interbody Fusion.

    PubMed

    Ahn, Junyoung; Tabaraee, Ehsan; Singh, Kern

    2015-07-01

    Minimally invasive transforaminal lumbar interbody fusion (MIS TLIF) is performed via tubular dilators thereby preserving the integrity of the paraspinal musculature. The decreased soft tissue disruption in the MIS technique has been associated with significantly decreased blood loss, shorter length of hospitalization, and an expedited return to work while maintaining comparable arthrodesis rates when compared with the open technique particularly in the setting of spondylolisthesis (isthmic and degenerative), recurrent symptomatic disk herniation, spinal stenosis, pseudoarthrosis, iatrogenic instability, and spinal trauma. The purpose of this article and the accompanying video wass to demonstrate the techniques for a primary, single-level MIS TLIF. PMID:26079840

  12. Minimally invasive surgery for gastric cancer.

    PubMed

    Güner, Ali; Hyung, Woo Jin

    2014-01-01

    The interest in minimally invasive surgery (MIS) has rapidly increased in recent decades and surgeons have adopted minimally invasive techniques due to its reduced invasiveness and numerous advantages for patients. With increased surgical experience and newly developed surgical instruments, MIS has become the preferred approach not only for benign disease but also for oncologic surgery. Recently, robotic systems have been developed to overcome difficulties of standard laparoscopic instruments during complex procedures. Its advantages including three-dimensional images, tremor filtering, motion scaling, articulated instruments, and stable retraction have created the opportunity to use robotic technology in many procedures including cancer surgery. Gastric cancer is one of the most common causes of cancer-related deaths worldwide. While its overall incidence has decreased worldwide, the proportion of early gastric cancer has increased mainly in eastern countries following mass screening programs. The shift in the paradigm of gastric cancer treatment is toward less invasive approaches in order to improve the patient's quality of life while adhering to oncological principles. In this review, we aimed to summarize the operative strategy and current literature in laparoscopic and robotic surgery for gastric cancer.

  13. Minimally Invasive Surgery for Inflammatory Bowel Disease

    PubMed Central

    Holder-Murray, Jennifer; Marsicovetere, Priscilla

    2015-01-01

    Abstract: Surgical management of inflammatory bowel disease is a challenging endeavor given infectious and inflammatory complications, such as fistula, and abscess, complex often postoperative anatomy, including adhesive disease from previous open operations. Patients with Crohn's disease and ulcerative colitis also bring to the table the burden of their chronic illness with anemia, malnutrition, and immunosuppression, all common and contributing independently as risk factors for increased surgical morbidity in this high-risk population. However, to reduce the physical trauma of surgery, technologic advances and worldwide experience with minimally invasive surgery have allowed laparoscopic management of patients to become standard of care, with significant short- and long-term patient benefits compared with the open approach. In this review, we will describe the current state-of the-art for minimally invasive surgery for inflammatory bowel disease and the caveats inherent with this practice in this complex patient population. Also, we will review the applicability of current and future trends in minimally invasive surgical technique, such as laparoscopic “incisionless,” single-incision laparoscopic surgery (SILS), robotic-assisted, and other techniques for the patient with inflammatory bowel disease. There can be no doubt that minimally invasive surgery has been proven to decrease the short- and long-term burden of surgery of these chronic illnesses and represents high-value care for both patient and society. PMID:25989341

  14. Cultural Diversity, Economic Development and Societal Instability

    PubMed Central

    Nettle, Daniel; Grace, James B.; Choisy, Marc; Cornell, Howard V.; Guégan, Jean-François; Hochberg, Michael E.

    2007-01-01

    Background Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation or α diversity, but also diversity between a nation and its neighbours or β diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are mediated by economic conditions. Methodology/Principal Findings We assembled a large cross-national dataset with information on α and β cultural diversity, economic conditions, and indices of societal instability. Structural equation modeling was used to evaluate the direct and indirect effects of cultural diversity on economics and societal stability. Results show that different types and domains of diversity have interacting effects. As previously documented, linguistic α diversity has a negative effect on economic performance, and we show that it is largely through this economic mechanism that it affects societal instability. For β diversity, the higher the linguistic diversity among nations in a region, the less stable the nation. But, religious β diversity has the opposite effect, reducing instability, particularly in the presence of high linguistic diversity. Conclusions Within-nation linguistic diversity is associated with reduced economic performance, which, in turn, increases societal instability. Nations which differ linguistically from their neighbors are also less stable. However, religious diversity between neighboring nations has the opposite effect, decreasing societal instability. PMID:17895970

  15. Cultural diversity, economic development and societal instability

    USGS Publications Warehouse

    Nettle, D.; Grace, J.B.; Choisy, M.; Cornell, H.V.; Guegan, J.-F.; Hochberg, M.E.

    2007-01-01

    Background. Social scientists have suggested that cultural diversity in a nation leads to societal instability. However, societal instability may be affected not only by within-nation on ?? diversity, but also diversity between a nation and its neighbours or ?? diversity. It is also necessary to distinguish different domains of diversity, namely linguistic, ethnic and religious, and to distinguish between the direct effects of diversity on societal instability, and effects that are mediated by economic conditions. Methodology/Principal Findings. We assembled a large cross-national dataset with information on ?? and ?? cultural diversity, economic conditions, and indices of societal instability. Structural equation modeling was used to evaluate the direct and indirect effects of cultural diversity on economics and societal stability. Results show that different type and domains of diversity have interacting effects. As previously documented, linguistic ?? diversity has a negative effect on economic performance, and we show that it is largely through this economic mechanism that it affects societal instability. For ?? diversity, the higher the linguistic diversity among nations in a region, the less stable the nation. But, religious ?? diversity has the opposite effect, reducing instability, particularly in the presence of high linguistic diversity. Conclusions. Within-nation linguistic diversity is associated with reduced economic performance, which, in turn, increases societal instability. Nations which differ linguistically from their neighbors are also less stable. However, religious diversity between, neighboring nations has the opposite effect, decreasing societal instability.

  16. Trophic network architecture of root-associated bacterial communities determines pathogen invasion and plant health.

    PubMed

    Wei, Zhong; Yang, Tianjie; Friman, Ville-Petri; Xu, Yangchun; Shen, Qirong; Jousset, Alexandre

    2015-01-01

    Host-associated bacterial communities can function as an important line of defence against pathogens in animals and plants. Empirical evidence and theoretical predictions suggest that species-rich communities are more resistant to pathogen invasions. Yet, the underlying mechanisms are unclear. Here, we experimentally test how the underlying resource competition networks of resident bacterial communities affect invasion resistance to the plant pathogen Ralstonia solanacearum in microcosms and in tomato plant rhizosphere. We find that bipartite resource competition networks are better predictors of invasion resistance compared with resident community diversity. Specifically, communities with a combination of stabilizing configurations (low nestedness and high connectance), and a clear niche overlap with the pathogen, reduce pathogen invasion success, constrain pathogen growth within invaded communities and have lower levels of diseased plants in greenhouse experiments. Bacterial resource competition network characteristics can thus be important in explaining positive diversity-invasion resistance relationships in bacterial rhizosphere communities. PMID:26400552

  17. Exploiting Allee effects for managing biological invasions.

    PubMed

    Tobin, Patrick C; Berec, Luděk; Liebhold, Andrew M

    2011-06-01

    Biological invasions are a global and increasing threat to the function and diversity of ecosystems. Allee effects (positive density dependence) have been shown to play an important role in the establishment and spread of non-native species. Although Allee effects can be considered a bane in conservation efforts, they can be a benefit in attempts to manage non-native species. Many biological invaders are subject to some form of an Allee effect, whether due to a need to locate mates, cooperatively feed or reproduce or avoid becoming a meal, yet attempts to highlight the specific exploitation of Allee effects in biological invasions are surprisingly unprecedented. In this review, we highlight current strategies that effectively exploit an Allee effect, and propose novel means by which Allee effects can be manipulated to the detriment of biological invaders. We also illustrate how the concept of Allee effects can be integral in risk assessments and in the prioritization of resources allocated to manage non-native species, as some species beset by strong Allee effects could be less successful as invaders. We describe how tactics that strengthen an existing Allee effect or create new ones could be used to manage biological invasions more effectively.

  18. Invasion and Management of Agricultural Alien Insects in China.

    PubMed

    Wan, Fang-Hao; Yang, Nian-Wan

    2016-01-01

    China is the world's fourth-largest country in terms of landmass. Its highly diverse biogeography presents opportunities for many invasive alien insects. However, physical and climate barriers sometimes prevent locally occurring species from spreading. China has 560 confirmed invasive alien species; 125 are insect pests, and 92 of these damage the agricultural ecosystem. The estimated annual economic loss due to alien invasive species is more than $18.9 billion. The most harmful invasive insects exhibit some common characteristics, such as high reproduction, competitive dominance, and high tolerance, and benefit from mutualist facilitation interactions. Regional cropping system structure adjustments have resulted in mono-agricultural ecosystems in cotton and other staple crops, providing opportunities for monophagous insect pests. Furthermore, human dietary shifts to fruits and vegetables and smallholder-based farming systems result in highly diverse agricultural ecosystems, which provide resource opportunities for polyphagous insects. Multiple cropping and widespread use of greenhouses provide continuous food and winter habitats for insect pests, greatly extending their geographic range. The current management system consists of early-warning, monitoring, eradication, and spread blocking technologies. This review provides valuable new synthetic information on integrated management practices based mainly on biological control for a number of invasive species. We encourage farmers and extension workers to be more involved in training and further research for novel protection methods that takes into consideration end users' needs.

  19. Evolutionary speed of species invasions.

    PubMed

    García-Ramos, Gisela; Rodríguez, Diego

    2002-04-01

    Successful invasion may depend of the capacity of a species to adjust genetically to a spatially varying environment. This research modeled a species invasion by examining the interaction between a quantitative genetic trait and population density. It assumed: (I) a quantitative genetic trait describes the adaptation of an individual to its local ecological conditions; (2) populations far from the local optimum grow more slowly than those near the optimum; and (3) the evolution of a trait depends on local population density, because differences in local population densities cause asymmetrical gene flow. This genetics-density interaction determined the propagation speed of populations. Numerical simulations showed that populations spread by advancing as two synchronic traveling waves, one for population density and one for trait adaptation. The form of the density wave was a step front that advances homogenizing populations at their carrying capacity; the adaptation wave was a curve with finite slope that homogenizes populations at full adaptation. The largest speed of population expansion, for a dimensionless analysis, corresponded to an almost homogeneous spatial environment when this model approached an ecological description such as the Fisher-Skellam's model. A large genetic response also favored faster speeds. Evolutionary speeds, in a natural scale, showed a wide range of rates that were also slower compared to models that only consider demographics. This evolutionary speed increased with high heritability, strong stabilizing selection, and high intrinsic growth rate. It decreased for steeper environmental gradients. Also indicated was an optimal dispersal rate over which evolutionary speed declined. This is expected because dispersal moves individuals further, but homogenizes populations genetically, making them maladapted. The evolutionary speed was compared to observed data. Furthermore, a moderate increase in the speed of expansion was predicted for

  20. Differential plant invasiveness is not always driven by host promiscuity with bacterial symbionts

    PubMed Central

    Klock, Metha M.; Barrett, Luke G.; Thrall, Peter H.; Harms, Kyle E.

    2016-01-01

    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

  1. Differential plant invasiveness is not always driven by host promiscuity with bacterial symbionts.

    PubMed

    Klock, Metha M; Barrett, Luke G; Thrall, Peter H; Harms, Kyle E

    2016-01-01

    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

  2. Managing diversity.

    PubMed

    Wagner, M

    1991-09-30

    One look at projections for the U.S. work force through the year 2000 shows why healthcare administrators will be facing some new challenges. With the majority of new workers belonging to minority groups, "managing diversity" has become the newest catch phrase as executives work to reduce tensions resulting from race, gender or culture-based differences among workers, while also learning to understand and value those differences.

  3. Modeling Hawaiian ecosystem degradation due to invasive plants under current and future climates

    USGS Publications Warehouse

    Vorsino, Adam E.; Fortini, Lucas B.; Amidon, Fred A.; Miller, Stephen E.; Jacobi, James D.; Price, Jonathan P.; `Ohukani`ohi`a Gon, Sam; Koob, Gregory A.

    2014-01-01

    Occupation of native ecosystems by invasive plant species alters their structure and/or function. In Hawaii, a subset of introduced plants is regarded as extremely harmful due to competitive ability, ecosystem modification, and biogeochemical habitat degradation. By controlling this subset of highly invasive ecosystem modifiers, conservation managers could significantly reduce native ecosystem degradation. To assess the invasibility of vulnerable native ecosystems, we selected a proxy subset of these invasive plants and developed robust ensemble species distribution models to define their respective potential distributions. The combinations of all species models using both binary and continuous habitat suitability projections resulted in estimates of species richness and diversity that were subsequently used to define an invasibility metric. The invasibility metric was defined from species distribution models with 0.8; True Skill Statistic >0.75) as evaluated per species. Invasibility was further projected onto a 2100 Hawaii regional climate change scenario to assess the change in potential habitat degradation. The distribution defined by the invasibility metric delineates areas of known and potential invasibility under current climate conditions and, when projected into the future, estimates potential reductions in native ecosystem extent due to climate-driven invasive incursion. We have provided the code used to develop these metrics to facilitate their wider use (Code S1). This work will help determine the vulnerability of native-dominated ecosystems to the combined threats of climate change and invasive species, and thus help prioritize ecosystem and species management actions.

  4. Molecular characterization and antibiotic resistance of group G streptococci in Israel: comparison of invasive, non-invasive and carriage isolates.

    PubMed

    Halperin, T; Levine, H; Korenman, Z; Burstein, S; Amber, R; Sela, T; Valinsky, L

    2016-10-01

    Beta-hemolytic group G streptococci (GGS) are increasingly recognized as a source of substantial morbidity, causing mild to severe sporadic infections as well as outbreaks. The purpose of this study was to determine the genetic diversity and antibiotic resistance of GGS in Israel in order to aid in prevention and control. A total of 325 GGS isolates were collected in Israel between 2007 and 2011 from three determined settings: (1) carriage (n = 60), an observational longitudinal carriage study in the IF, (2) non-invasive (n = 166), clinical sporadic and epidemic non-invasive cases in the IDF, and (3) invasive (n = 99) cases of bacteremia collected during this period in Israel from a similar age group, at the national Streptococcal Reference Center. All isolates were characterized genetically and by their antibiotic-resistance profile. emm typing revealed 35 distinct types and subtypes among 228 S. dysgalactiae subsp. equisimilis (SDSE) isolates, with high genetic diversity. An additional 97 GGS were identified as Streptococcus anginosus (SAG). The proportion of SDSE was higher in the invasive (100 %) and non-invasive (63.8 %) isolates compared to the carriage ones (38.3 %). Clindamycin, erythromycin, azithromycin and tetracycline resistance was detected in 6.6 %, 8.6 %, 9.7 % and 37.6 % of isolates, respectively. Overall, the most resistant isolates were in the invasive group and the fewest were in the SAG group. Considerable genetic diversity and common antibiotic resistance were revealed among GGS strains which differed according to the epidemiologic settings. Further clinical, epidemiological and basic research of GGS as a pathogen is warranted.

  5. Molecular characterization and antibiotic resistance of group G streptococci in Israel: comparison of invasive, non-invasive and carriage isolates.

    PubMed

    Halperin, T; Levine, H; Korenman, Z; Burstein, S; Amber, R; Sela, T; Valinsky, L

    2016-10-01

    Beta-hemolytic group G streptococci (GGS) are increasingly recognized as a source of substantial morbidity, causing mild to severe sporadic infections as well as outbreaks. The purpose of this study was to determine the genetic diversity and antibiotic resistance of GGS in Israel in order to aid in prevention and control. A total of 325 GGS isolates were collected in Israel between 2007 and 2011 from three determined settings: (1) carriage (n = 60), an observational longitudinal carriage study in the IF, (2) non-invasive (n = 166), clinical sporadic and epidemic non-invasive cases in the IDF, and (3) invasive (n = 99) cases of bacteremia collected during this period in Israel from a similar age group, at the national Streptococcal Reference Center. All isolates were characterized genetically and by their antibiotic-resistance profile. emm typing revealed 35 distinct types and subtypes among 228 S. dysgalactiae subsp. equisimilis (SDSE) isolates, with high genetic diversity. An additional 97 GGS were identified as Streptococcus anginosus (SAG). The proportion of SDSE was higher in the invasive (100 %) and non-invasive (63.8 %) isolates compared to the carriage ones (38.3 %). Clindamycin, erythromycin, azithromycin and tetracycline resistance was detected in 6.6 %, 8.6 %, 9.7 % and 37.6 % of isolates, respectively. Overall, the most resistant isolates were in the invasive group and the fewest were in the SAG group. Considerable genetic diversity and common antibiotic resistance were revealed among GGS strains which differed according to the epidemiologic settings. Further clinical, epidemiological and basic research of GGS as a pathogen is warranted. PMID:27325440

  6. Minimally invasive mediastinal surgery

    PubMed Central

    Melfi, Franca M. A.; Mussi, Alfredo

    2016-01-01

    In the past, mediastinal surgery was associated with the necessity of a maximum exposure, which was accomplished through various approaches. In the early 1990s, many surgical fields, including thoracic surgery, observed the development of minimally invasive techniques. These included video-assisted thoracic surgery (VATS), which confers clear advantages over an open approach, such as less trauma, short hospital stay, increased cosmetic results and preservation of lung function. However, VATS is associated with several disadvantages. For this reason, it is not routinely performed for resection of mediastinal mass lesions, especially those located in the anterior mediastinum, a tiny and remote space that contains vital structures at risk of injury. Robotic systems can overcome the limits of VATS, offering three-dimensional (3D) vision and wristed instrumentations, and are being increasingly used. With regards to thymectomy for myasthenia gravis (MG), unilateral and bilateral VATS approaches have demonstrated good long-term neurologic results with low complication rates. Nevertheless, some authors still advocate the necessity of maximum exposure, especially when considering the distribution of normal and ectopic thymic tissue. In recent studies, the robotic approach has shown to provide similar neurological outcomes when compared to transsternal and VATS approaches, and is associated with a low morbidity. Importantly, through a unilateral robotic technique, it is possible to dissect and remove at least the same amount of mediastinal fat tissue. Preliminary results on early-stage thymomatous disease indicated that minimally invasive approaches are safe and feasible, with a low rate of pleural recurrence, underlining the necessity of a “no-touch” technique. However, especially for thymomatous disease characterized by an indolent nature, further studies with long follow-up period are necessary in order to assess oncologic and neurologic results through minimally

  7. Global patterns in threats to vertebrates by biological invasions.

    PubMed

    Bellard, C; Genovesi, P; Jeschke, J M

    2016-01-27

    Biological invasions as drivers of biodiversity loss have recently been challenged. Fundamentally, we must know where species that are threatened by invasive alien species (IAS) live, and the degree to which they are threatened. We report the first study linking 1372 vertebrates threatened by more than 200 IAS from the completely revised Global Invasive Species Database. New maps of the vulnerability of threatened vertebrates to IAS permit assessments of whether IAS have a major influence on biodiversity, and if so, which taxonomic groups are threatened and where they are threatened. We found that centres of IAS-threatened vertebrates are concentrated in the Americas, India, Indonesia, Australia and New Zealand. The areas in which IAS-threatened species are located do not fully match the current hotspots of invasions, or the current hotspots of threatened species. The relative importance of biological invasions as drivers of biodiversity loss clearly varies across regions and taxa, and changes over time, with mammals from India, Indonesia, Australia and Europe are increasingly being threatened by IAS. The chytrid fungus primarily threatens amphibians, whereas invasive mammals primarily threaten other vertebrates. The differences in IAS threats between regions and taxa can help efficiently target IAS, which is essential for achieving the Strategic Plan 2020 of the Convention on Biological Diversity.

  8. Global patterns in threats to vertebrates by biological invasions.

    PubMed

    Bellard, C; Genovesi, P; Jeschke, J M

    2016-01-27

    Biological invasions as drivers of biodiversity loss have recently been challenged. Fundamentally, we must know where species that are threatened by invasive alien species (IAS) live, and the degree to which they are threatened. We report the first study linking 1372 vertebrates threatened by more than 200 IAS from the completely revised Global Invasive Species Database. New maps of the vulnerability of threatened vertebrates to IAS permit assessments of whether IAS have a major influence on biodiversity, and if so, which taxonomic groups are threatened and where they are threatened. We found that centres of IAS-threatened vertebrates are concentrated in the Americas, India, Indonesia, Australia and New Zealand. The areas in which IAS-threatened species are located do not fully match the current hotspots of invasions, or the current hotspots of threatened species. The relative importance of biological invasions as drivers of biodiversity loss clearly varies across regions and taxa, and changes over time, with mammals from India, Indonesia, Australia and Europe are increasingly being threatened by IAS. The chytrid fungus primarily threatens amphibians, whereas invasive mammals primarily threaten other vertebrates. The differences in IAS threats between regions and taxa can help efficiently target IAS, which is essential for achieving the Strategic Plan 2020 of the Convention on Biological Diversity. PMID:26817767

  9. Invasive prey indirectly increase predation on their native competitors.

    PubMed

    Castorani, Max C N; Hovel, Kevin A

    2015-07-01

    Ecological theory predicts that invasive prey can interact with native prey directly by competing for shared resources or indirectly by changing the abundance or behavior of shared native predators. However, both the study and management of invasive prey have historically overlooked indirect effects. In southern California estuaries, introduction of the Asian nest mussel Arcuatula senhousia has been linked to profound changes in native bivalve assemblages, but the mechanisms of these interactions remain unclear. We performed three field experiments to assess the mechanisms of competition between Arcuatula and native bivalves, and evaluated the potential for Arcuatula to indirectly mediate native predator-prey dynamics. We found that Arcuatula reduces the diversity, abundance, and size of native bivalve recruits by preemptively exploiting space in surface sediments. When paired with native shallow-dwelling clams (Chione undatella and Laevicardium substriatum), Arcuatula reduces adult survival through overgrowth competition. However, Arcuatula also attracts native predators, causing apparent competition by indirectly increasing predation of native clams, especially for poorly defended species. Therefore, invasive prey can indirectly increase predation rates on native competitors by changing the behavior of shared native predators, but the magnitude of apparent competition strongly depends on the vulnerability of natives to predation. Interestingly, our results indicate that the vulnerability of invasive prey to predation can greatly exacerbate impacts on their native competitors. Our findings suggest that consideration of both direct and indirect effects of invasive prey, as well as native predator-prey relationships, should lead to more effective invasive species management.

  10. Bioterrorism and invasive species.

    PubMed

    Chomel, B B; Sun, B

    2010-08-01

    The risk of dispersing invasive species, especially human pathogens, through acts of bioterrorism, cannot be neglected. However, that risk appears quite low in comparison with the risk of dispersing animal pathogens that could dramatically burden the agricultural economy of food animal producing countries, such as Australia and countries in Europe and North and South America. Although it is not directly related to bioterrorism, the intentional release of non-native species, particularly undesired companion animals or wildlife, may also have a major economic impact on the environment and, possibly, on animal and human health, in the case of accidental release of zoonotic agents.

  11. Rapid increase in growth and productivity can aid invasions by a non-native tree.

    PubMed

    Dudeque Zenni, Rafael; Lacerda da Cunha, Wanderson; Sena, Guilherme

    2016-01-01

    Research on biological invasions has produced detailed theories describing range expansions of introduced populations. However, current knowledge of evolutionary factors associated with invasive range expansions, especially those related to rapid evolution of long-lived organisms, is still rudimentary. Here, we used a system of six 40-year-old invasive pine populations that originated from replicated introduction events to study evolution in productivity, growth, and chemical defence traits. We tested the hypotheses that invasive populations were undergoing rapid phenotypic change as populations spread, that populations exhibit trade-offs between evolution in growth and chemical defences, and that rates of rapid evolution in plant growth and productivity effect rates of invasion. Although all invasions started from replicated pools of genetic material and equal propagule pressure, we found divergence in mean values for the six invasive populations in the six traits measured. Not only were there between-population variations but also invasive populations were also rapidly changing along each invasive population expansion. Two populations displayed greater leaf areas (LAs) and smaller specific LAs (SLAs) during range expansion. Four populations had faster growth rates at the leading edge of the invasion front in comparison with plants at the rear edge. In terms of total plant defences, non-volatile resin increased in plants along one invasion gradient and decreased in a second, total needle phenolics increased in plants along one invasion gradient and total wood phenolics increased in plants along the one invasion gradient and decreased in a second. We found no trade-offs between investments in growth and chemical defence. Also, faster rates of change in growth rate and LA were positively associated with greater dispersal distances of invasive populations, suggesting rapid evolution may increase invasiveness. Understanding the roles of both natural and human

  12. Rapid increase in growth and productivity can aid invasions by a non-native tree.

    PubMed

    Dudeque Zenni, Rafael; Lacerda da Cunha, Wanderson; Sena, Guilherme

    2016-01-01

    Research on biological invasions has produced detailed theories describing range expansions of introduced populations. However, current knowledge of evolutionary factors associated with invasive range expansions, especially those related to rapid evolution of long-lived organisms, is still rudimentary. Here, we used a system of six 40-year-old invasive pine populations that originated from replicated introduction events to study evolution in productivity, growth, and chemical defence traits. We tested the hypotheses that invasive populations were undergoing rapid phenotypic change as populations spread, that populations exhibit trade-offs between evolution in growth and chemical defences, and that rates of rapid evolution in plant growth and productivity effect rates of invasion. Although all invasions started from replicated pools of genetic material and equal propagule pressure, we found divergence in mean values for the six invasive populations in the six traits measured. Not only were there between-population variations but also invasive populations were also rapidly changing along each invasive population expansion. Two populations displayed greater leaf areas (LAs) and smaller specific LAs (SLAs) during range expansion. Four populations had faster growth rates at the leading edge of the invasion front in comparison with plants at the rear edge. In terms of total plant defences, non-volatile resin increased in plants along one invasion gradient and decreased in a second, total needle phenolics increased in plants along one invasion gradient and total wood phenolics increased in plants along the one invasion gradient and decreased in a second. We found no trade-offs between investments in growth and chemical defence. Also, faster rates of change in growth rate and LA were positively associated with greater dispersal distances of invasive populations, suggesting rapid evolution may increase invasiveness. Understanding the roles of both natural and human

  13. Rapid increase in growth and productivity can aid invasions by a non-native tree

    PubMed Central

    Dudeque Zenni, Rafael; Lacerda da Cunha, Wanderson; Sena, Guilherme

    2016-01-01

    Research on biological invasions has produced detailed theories describing range expansions of introduced populations. However, current knowledge of evolutionary factors associated with invasive range expansions, especially those related to rapid evolution of long-lived organisms, is still rudimentary. Here, we used a system of six 40-year-old invasive pine populations that originated from replicated introduction events to study evolution in productivity, growth, and chemical defence traits. We tested the hypotheses that invasive populations were undergoing rapid phenotypic change as populations spread, that populations exhibit trade-offs between evolution in growth and chemical defences, and that rates of rapid evolution in plant growth and productivity effect rates of invasion. Although all invasions started from replicated pools of genetic material and equal propagule pressure, we found divergence in mean values for the six invasive populations in the six traits measured. Not only were there between-population variations but also invasive populations were also rapidly changing along each invasive population expansion. Two populations displayed greater leaf areas (LAs) and smaller specific LAs (SLAs) during range expansion. Four populations had faster growth rates at the leading edge of the invasion front in comparison with plants at the rear edge. In terms of total plant defences, non-volatile resin increased in plants along one invasion gradient and decreased in a second, total needle phenolics increased in plants along one invasion gradient and total wood phenolics increased in plants along the one invasion gradient and decreased in a second. We found no trade-offs between investments in growth and chemical defence. Also, faster rates of change in growth rate and LA were positively associated with greater dispersal distances of invasive populations, suggesting rapid evolution may increase invasiveness. Understanding the roles of both natural and human

  14. Valuing Diversity

    PubMed Central

    Fryer, Roland G.; Loury, Glenn C.

    2014-01-01

    This paper explores the economics of diversity-enhancing policies. A model is proposed in which heterogeneous agents, distinguished by skill level and social identity, purchase productive opportunities in a competitive market. We analyze policies designed to raise the status of a disadvantaged identity group. When agent identity is contractible, efficient policy grants preferred access to slots but offers no direct assistance for acquiring skills. When identity is not contractible, efficient policy provides universal subsidies to skill development when the fraction of the disadvantaged group at the skill development margin is larger than their share at the slot assignment margin. PMID:25525280

  15. Ultrasonic non invasive techniques for microbiological instrumentation

    NASA Astrophysics Data System (ADS)

    Elvira, L.; Sierra, C.; Galán, B.; Resa, P.

    2010-01-01

    Non invasive techniques based on ultrasounds have advantageous features to study, characterize and monitor microbiological and enzymatic reactions. These processes may change the sound speed, viscosity or particle distribution size of the medium where they take place, which makes possible their analysis using ultrasonic techniques. In this work, two different systems for the analysis of microbiological liquid media based on ultrasounds are presented. In first place, an industrial application based on an ultrasonic monitoring technique for microbiological growth detection in milk is shown. Such a system may improve the quality control strategies in food production factories, being able to decrease the time required to detect possible contaminations in packed products. Secondly, a study about the growing of the Escherichia coli DH5 α in different conditions is presented. It is shown that the use of ultrasonic non invasive characterization techniques in combination with other conventional measurements like optical density provides complementary information about the metabolism of these bacteria.

  16. Grazing maintains native plant diversity and promotes community stability in an annual grassland.

    PubMed

    Beck, Jared J; Hernández, Daniel L; Pasari, Jae R; Zavaleta, Erika S

    2015-07-01

    Maintaining native biodiversity in grasslands requires management and mitigation of anthropogenic changes that have altered resource availability, grazing regimes, and community composition. In California (USA), high levels of atmospheric nitrogen (N) deposition have facilitated the invasion of exotic grasses, posing a threat to the diverse plant and insect communities endemic to serpentine grasslands. Cattle grazing has been employed to mitigate the consequences of exotic grass invasion, but the ecological effects of grazing in this system are not fully understood. To characterize the effects of realistic N deposition on serpentine plant communities and to evaluate the efficacy of grazing as a management tool, we performed a factorial experiment adding N and excluding large herbivores in California's largest serpentine grassland. Although we observed significant interannual variation in community composition related to climate in our six-year study, exotic cover was consistently and negatively correlated with native plant richness. Sustained low-level N addition did not influence plant community composition, but grazing reduced grass abundance while maintaining greater native forb cover, native plant diversity, and species richness in comparison to plots excluding large herbivores. Furthermore, grazing increased the temporal stability of plant communities by decreasing year-to-year variation in native forb cover, native plant diversity, and native species richness. Taken together, our findings demonstrate that moderate-intensity cattle grazing can be used to restrict the invasive potential of exotic grasses and maintain native plant communities in serpentine grasslands. We hypothesize that the reduced temporal variability in serpentine plant communities managed by grazing may directly benefit populations of the threatened Edith's Bay checkerspot butterfly (Euphydryas editha bayensis). PMID:26485954

  17. Grazing maintains native plant diversity and promotes community stability in an annual grassland.

    PubMed

    Beck, Jared J; Hernández, Daniel L; Pasari, Jae R; Zavaleta, Erika S

    2015-07-01

    Maintaining native biodiversity in grasslands requires management and mitigation of anthropogenic changes that have altered resource availability, grazing regimes, and community composition. In California (USA), high levels of atmospheric nitrogen (N) deposition have facilitated the invasion of exotic grasses, posing a threat to the diverse plant and insect communities endemic to serpentine grasslands. Cattle grazing has been employed to mitigate the consequences of exotic grass invasion, but the ecological effects of grazing in this system are not fully understood. To characterize the effects of realistic N deposition on serpentine plant communities and to evaluate the efficacy of grazing as a management tool, we performed a factorial experiment adding N and excluding large herbivores in California's largest serpentine grassland. Although we observed significant interannual variation in community composition related to climate in our six-year study, exotic cover was consistently and negatively correlated with native plant richness. Sustained low-level N addition did not influence plant community composition, but grazing reduced grass abundance while maintaining greater native forb cover, native plant diversity, and species richness in comparison to plots excluding large herbivores. Furthermore, grazing increased the temporal stability of plant communities by decreasing year-to-year variation in native forb cover, native plant diversity, and native species richness. Taken together, our findings demonstrate that moderate-intensity cattle grazing can be used to restrict the invasive potential of exotic grasses and maintain native plant communities in serpentine grasslands. We hypothesize that the reduced temporal variability in serpentine plant communities managed by grazing may directly benefit populations of the threatened Edith's Bay checkerspot butterfly (Euphydryas editha bayensis).

  18. Coupling legacy geomorphic surface facies to riparian vegetation: Assessing red cedar invasion along the Missouri River downstream of Gavins Point dam, South Dakota

    NASA Astrophysics Data System (ADS)

    Greene, Samantha L.; Knox, James C.

    2014-01-01

    Floods increase fluvial complexity by eroding established surfaces and creating new alluvial surfaces. As dams regulate channel flow, fluvial complexity often decreases and the hydro-eco-geomorphology of the riparian habitat changes. Along the Missouri River, flow regulation resulted in channel incision of 1-3 m within the study area and disconnected the pre-dam floodplain from the channel. Evidence of fluvial complexity along the pre-dam Missouri River floodplain can be observed through the diverse depositional environments represented by areas of varying soil texture. This study evaluates the role of flow regulation and depositional environment along the Missouri River in the riparian invasion of red cedar downstream of Gavins Point dam, the final dam on the Missouri River. We determine whether invasion began before or after flow regulation, determine patterns of invasion using Bayesian t-tests, and construct a Bayesian multivariate linear model of invaded surfaces. We surveyed 59 plots from 14 riparian cottonwood stands for tree age, plot composition, plot stem density, and soil texture. Red cedars existed along the floodplain prior to regulation, but at a much lower density than today. We found 2 out of 565 red cedars established prior to regulation. Our interpretation of depositional environments shows that the coarser, sandy soils reflect higher energy depositional pre-dam surfaces that were geomorphically active islands and point bars prior to flow regulation and channel incision. The finer, clayey soils represent lower energy depositional pre-dam surfaces, such as swales or oxbow depressions. When determining patterns of invasion for use in a predictive statistical model, we found that red cedar primarily establishes on the higher energy depositional pre-dam surfaces. In addition, as cottonwood age and density decrease, red cedar density tends to increase. Our findings indicate that flow regulation caused hydrogeomorphic changes within the study area that

  19. Malignant cancer and invasive placentation

    PubMed Central

    D'Souza, Alaric W.; Wagner, Günter P.

    2014-01-01

    Cancer metastasis is an invasive process that involves the transplantation of cells into new environments. Since human placentation is also invasive, hypotheses about a relationship between invasive placentation in eutherian mammals and metastasis have been proposed. The relationship between metastatic cancer and invasive placentation is usually presented in terms of antagonistic pleiotropy. According to this hypothesis, evolution of invasive placentation also established the mechanisms for cancer metastasis. Here, in contrast, we argue that the secondary evolution of less invasive placentation in some mammalian lineages may have resulted in positive pleiotropic effects on cancer survival by lowering malignancy rates. These positive pleiotropic effects would manifest themselves as resistance to cancer cell invasion. To provide a preliminary test of this proposal, we re-analyze data from Priester and Mantel (Occurrence of tumors in domestic animals. Data from 12 United States and Canadian colleges of veterinary medicine. J Natl Cancer Inst 1971;47:1333-44) about malignancy rates in cows, horses, cats and dogs. From our analysis we found that equines and bovines, animals with less invasive placentation, have lower rates of metastatic cancer than felines and canines in skin and glandular epithelial cancers as well as connective tissue sarcomas. We conclude that a link between type of placentation and species-specific malignancy rates is more likely related to derived mechanisms that suppress invasion rather than different degrees of fetal placental aggressiveness. PMID:25324490

  20. Invasions in heterogeneous habitats in the presence of advection.

    PubMed

    Vergni, Davide; Iannaccone, Sandro; Berti, Stefano; Cencini, Massimo

    2012-05-21

    We investigate invasions from a biological reservoir to an initially empty, heterogeneous habitat in the presence of advection. The habitat consists of a periodic alternation of favorable and unfavorable patches. In the latter the population dies at fixed rate. In the former it grows either with the logistic or with an Allee effect type dynamics, where the population has to overcome a threshold to grow. We study the conditions for successful invasions and the speed of the invasion process, which is numerically and analytically investigated in several limits. Generically advection enhances the downstream invasion speed but decreases the population size of the invading species, and can even inhibit the invasion process. Remarkably, however, the rate of population increase, which quantifies the invasion efficiency, is maximized by an optimal advection velocity. In models with Allee effect, differently from the logistic case, above a critical unfavorable patch size the population localizes in a favorable patch, being unable to invade the habitat. However, we show that advection, when intense enough, may activate the invasion process.

  1. Schwann cells induce cancer cell dispersion and invasion

    PubMed Central

    Deborde, Sylvie; Lyubchik, Anna; Zhou, Yi; He, Shizhi; McNamara, William F.; Chernichenko, Natalya; Lee, Sei-Young; Barajas, Fernando; Chen, Chun-Hao; Bakst, Richard L.; Vakiani, Efsevia; He, Shuangba; Hall, Alan; Wong, Richard J.

    2016-01-01

    Nerves enable cancer progression, as cancers have been shown to extend along nerves through the process of perineural invasion, which carries a poor prognosis. Furthermore, the innervation of some cancers promotes growth and metastases. It remains unclear, however, how nerves mechanistically contribute to cancer progression. Here, we demonstrated that Schwann cells promote cancer invasion through direct cancer cell contact. Histological evaluation of murine and human cancer specimens with perineural invasion uncovered a subpopulation of Schwann cells that associates with cancer cells. Coculture of cancer cells with dorsal root ganglion extracts revealed that Schwann cells direct cancer cells to migrate toward nerves and promote invasion in a contact-dependent manner. Upon contact, Schwann cells induced the formation of cancer cell protrusions in their direction and intercalated between the cancer cells, leading to cancer cell dispersion. The formation of these processes was dependent on Schwann cell expression of neural cell adhesion molecule 1 (NCAM1) and ultimately promoted perineural invasion. Moreover, NCAM1-deficient mice showed decreased neural invasion and less paralysis. Such Schwann cell behavior reflects normal Schwann cell programs that are typically activated in nerve repair but are instead exploited by cancer cells to promote perineural invasion and cancer progression. PMID:26999607

  2. Schwann cells induce cancer cell dispersion and invasion.

    PubMed

    Deborde, Sylvie; Omelchenko, Tatiana; Lyubchik, Anna; Zhou, Yi; He, Shizhi; McNamara, William F; Chernichenko, Natalya; Lee, Sei-Young; Barajas, Fernando; Chen, Chun-Hao; Bakst, Richard L; Vakiani, Efsevia; He, Shuangba; Hall, Alan; Wong, Richard J

    2016-04-01

    Nerves enable cancer progression, as cancers have been shown to extend along nerves through the process of perineural invasion, which carries a poor prognosis. Furthermore, the innervation of some cancers promotes growth and metastases. It remains unclear, however, how nerves mechanistically contribute to cancer progression. Here, we demonstrated that Schwann cells promote cancer invasion through direct cancer cell contact. Histological evaluation of murine and human cancer specimens with perineural invasion uncovered a subpopulation of Schwann cells that associates with cancer cells. Coculture of cancer cells with dorsal root ganglion extracts revealed that Schwann cells direct cancer cells to migrate toward nerves and promote invasion in a contact-dependent manner. Upon contact, Schwann cells induced the formation of cancer cell protrusions in their direction and intercalated between the cancer cells, leading to cancer cell dispersion. The formation of these processes was dependent on Schwann cell expression of neural cell adhesion molecule 1 (NCAM1) and ultimately promoted perineural invasion. Moreover, NCAM1-deficient mice showed decreased neural invasion and less paralysis. Such Schwann cell behavior reflects normal Schwann cell programs that are typically activated in nerve repair but are instead exploited by cancer cells to promote perineural invasion and cancer progression.

  3. Clarifying debates in invasion biology: a survey of invasion biologists.

    PubMed

    Young, Ashley M; Larson, Brendon M H

    2011-10-01

    Invasion biology is a relatively new field, so there are ongoing debates about foundational issues regarding terminology and assessment of the causes and consequences of invasive species. These debates largely reflect differing views about the extent to which invasion biologists should advocate on behalf of native species. We surveyed reviewers of the journal Biological Invasions to obtain a better sense of how invasion biologists evaluate several foundational issues. We received 422 replies, which represented a very good response rate for an online survey of 42.5% of those contacted. Responses to several debates in the field were distributed bimodally, but respondents consistently indicated that contemporary biological invasions are unprecedented. Even still, this was not seen as justification for exaggerated language (hyperbole). In contrast to prevalent claims in the literature, only 27.3% of respondents ranked invasive species as the first or second greatest threat to biodiversity. The responses also highlighted the interaction of invasive species with other threats and the role of human activity in their spread. Finally, the respondents agreed that they need to be both more objective and better at communicating their results so that those results can be effectively integrated into management. PMID:21757195

  4. Using scenarios to assess possible future impacts of invasive species in the Laurentian Great Lakes

    USGS Publications Warehouse

    Lauber, T. Bruce; Stedman, Richard C.; Connelly, Nancy A; Rudstam, Lars G.; Ready, Richard C; Poe, Gregory L; Bunnell, David; Hook, Tomas O.; Koops, Marten A.; Ludsin, Stuart A.; Rutherford, Edward S; Wittmann, Marion E.

    2016-01-01

    The expected impacts of invasive species are key considerations in selecting policy responses to potential invasions. But predicting the impacts of invasive species is daunting, particularly in large systems threatened by multiple invasive species, such as North America’s Laurentian Great Lakes. We developed and evaluated a scenario-building process that relied on an expert panel to assess possible future impacts of aquatic invasive species on recreational fishing in the Great Lakes. To maximize its usefulness to policy makers, this process was designed to be implemented relatively rapidly and consider a range of species. The expert panel developed plausible, internally-consistent invasion scenarios for 5 aquatic invasive species, along with subjective probabilities of those scenarios. We describe these scenarios and evaluate this approach for assessing future invasive species impacts. The panel held diverse opinions about the likelihood of the scenarios, and only one scenario with impacts on sportfish species was considered likely by most of the experts. These outcomes are consistent with the literature on scenario building, which advocates for developing a range of plausible scenarios in decision making because the uncertainty of future conditions makes the likelihood of any particular scenario low. We believe that this scenario-building approach could contribute to policy decisions about whether and how to address the possible impacts of invasive species. In this case, scenarios could allow policy makers to narrow the range of possible impacts on Great Lakes fisheries they consider and help set a research agenda for further refining invasive species predictions.

  5. Predator diversity effects in an exotic freshwater food web.

    PubMed

    Naddafi, Rahmat; Rudstam, Lars G

    2013-01-01

    Cascading trophic interactions are often defined as the indirect effects of a predator on primary producers through the effect of the predator on herbivores. These effects can be both direct through removal of herbivores [density-mediated indirect interactions (DMIIs)] or indirect through changes in the behavior of the herbivores [trait-mediated indirect interactions (TMIIs)]. How the relative importance of these two indirect interactions varies with predator diversity remains poorly understood. We tested the effect of predator diversity on both TMIIs and DMIIs on phytoplankton using two competitive invasive dreissenid mussel species (zebra mussel and quagga mussel) as the herbivores and combinations of one, two or all three species of the predators pumpkinseed sunfish, round goby, and rusty crayfish. Predators had either direct access to mussels and induced both TMII and DMII, or no direct access and induced only TMII through the presence of risk cues. In both sets of treatments, the predators induced a trophic cascade which resulted in more phytoplankton remaining with predators present than with only mussels present. The trophic cascade was weaker in three-predator and two-predator treatments than in one-predator treatments when predators had direct access to dreissenids (DMIIs and TMIIs). Crayfish had higher cascading effects on phytoplankton than both pumpkinseed and round goby. Increased predator diversity decreased the strength of DMIIs but had no effect on the strength of TMIIs. The strength of TMIIs was higher with zebra than quagga mussels. Our study suggests that inter-specific interference among predators in multi-species treatments weakens the consumptive cascading effects of predation on lower trophic levels whereas the importance of predator diversity on trait mediated effects depends on predator identity. PMID:23991126

  6. Predator Diversity Effects in an Exotic Freshwater Food Web

    PubMed Central

    Naddafi, Rahmat; Rudstam, Lars G.

    2013-01-01

    Cascading trophic interactions are often defined as the indirect effects of a predator on primary producers through the effect of the predator on herbivores. These effects can be both direct through removal of herbivores [density-mediated indirect interactions (DMIIs)] or indirect through changes in the behavior of the herbivores [trait-mediated indirect interactions (TMIIs)]. How the relative importance of these two indirect interactions varies with predator diversity remains poorly understood. We tested the effect of predator diversity on both TMIIs and DMIIs on phytoplankton using two competitive invasive dreissenid mussel species (zebra mussel and quagga mussel) as the herbivores and combinations of one, two or all three species of the predators pumpkinseed sunfish, round goby, and rusty crayfish. Predators had either direct access to mussels and induced both TMII and DMII, or no direct access and induced only TMII through the presence of risk cues. In both sets of treatments, the predators induced a trophic cascade which resulted in more phytoplankton remaining with predators present than with only mussels present. The trophic cascade was weaker in three-predator and two-predator treatments than in one-predator treatments when predators had direct access to dreissenids (DMIIs and TMIIs). Crayfish had higher cascading effects on phytoplankton than both pumpkinseed and round goby. Increased predator diversity decreased the strength of DMIIs but had no effect on the strength of TMIIs. The strength of TMIIs was higher with zebra than quagga mussels. Our study suggests that inter-specific interference among predators in multi-species treatments weakens the consumptive cascading effects of predation on lower trophic levels whereas the importance of predator diversity on trait mediated effects depends on predator identity. PMID:23991126

  7. Drought and ice plant invasion in Bodega Bay, California

    NASA Astrophysics Data System (ADS)

    Weill, A.

    2014-12-01

    Ice plant (Carpobrotus edulis) is a succulent native to South Africa that is widespread in coastal California. Ice plant invasion is facilitated by the plant's ability to compete for water. More frequent drought due to climate change could enhance the invasive potential of ice plant due to its succulent properties and potential to access and compete for water under drought conditions. However, ice plant spread may be slowed due to water stress under drought despite a potential competitive advantage. We test the alternative hypotheses that invasive potential increases or decreases during times of drought by analyzing ice plant spread during past droughts at Bodega Bay, California using analysis of aerial photographs taken over the last two decades. The results of this analysis may reveal how ice plant may behave in future drought years and provide useful information for invasive species management.

  8. Dietary Flexibility Aids Asian Earthworm Invasion in North American Forests

    EPA Science Inventory

    On a local scale, invasiveness of introduced species and invasibility of habitats together determine invasion success. A key issue in invasion ecology has been how to quantify the contribution of species invasiveness and habitat invasibility separately. Conventional approaches, s...

  9. Non-invasive wearable electrochemical sensors: a review.

    PubMed

    Bandodkar, Amay J; Wang, Joseph

    2014-07-01

    Wearable sensors have garnered considerable recent interest owing to their tremendous promise for a plethora of applications. Yet the absence of reliable non-invasive chemical sensors has greatly hindered progress in the area of on-body sensing. Electrochemical sensors offer considerable promise as wearable chemical sensors that are suitable for diverse applications owing to their high performance, inherent miniaturization, and low cost. A wide range of wearable electrochemical sensors and biosensors has been developed for real-time non-invasive monitoring of electrolytes and metabolites in sweat, tears, or saliva as indicators of a wearer's health status. With continued innovation and attention to key challenges, such non-invasive electrochemical sensors and biosensors are expected to open up new exciting avenues in the field of wearable wireless sensing devices and body-sensor networks, and thus find considerable use in a wide range of personal health-care monitoring applications, as well as in sport and military applications.

  10. Non-invasive Assessments of Adipose Tissue Metabolism In Vitro.

    PubMed

    Abbott, Rosalyn D; Borowsky, Francis E; Quinn, Kyle P; Bernstein, David L; Georgakoudi, Irene; Kaplan, David L

    2016-03-01

    Adipose tissue engineering is a diverse area of research where the developed tissues can be used to study normal adipose tissue functions, create disease models in vitro, and replace soft tissue defects in vivo. Increasing attention has been focused on the highly specialized metabolic pathways that regulate energy storage and release in adipose tissues which affect local and systemic outcomes. Non-invasive, dynamic measurement systems are useful to track these metabolic pathways in the same tissue model over time to evaluate long term cell growth, differentiation, and development within tissue engineering constructs. This approach reduces costs and time in comparison to more traditional destructive methods such as biochemical and immunochemistry assays and proteomics assessments. Towards this goal, this review will focus on important metabolic functions of adipose tissues and strategies to evaluate them with non-invasive in vitro methods. Current non-invasive methods, such as measuring key metabolic markers and endogenous contrast imaging will be explored.

  11. Biogenic disturbance determines invasion success in a subtidal soft-sediment system.

    PubMed

    Lohrer, Andrew M; Chiaroni, Luca D; Hewitt, Judi E; Thrush, Simon F

    2008-05-01

    Theoretically, disturbance and diversity can influence the success of invasive colonists if (1) resource limitation is a prime determinant of invasion success and (2) disturbance and diversity affect the availability of required resources. However, resource limitation is not of overriding importance in all systems, as exemplified by marine soft sediments, one of Earth's most widespread habitat types. Here, we tested the disturbance-invasion hypothesis in a marine soft-sediment system by altering rates of biogenic disturbance and tracking the natural colonization of plots by invasive species. Levels of sediment disturbance were controlled by manipulating densities of burrowing spatangoid urchins, the dominant biogenic sediment mixers in the system. Colonization success by two invasive species (a gobiid fish and a semelid bivalve) was greatest in plots with sediment disturbance rates < 500 cm(3) x m(-2) x d(-1), at the low end of the experimental disturbance gradient (0 to > 9000 cm(3) x m(-2) x d(-1)). Invasive colonization declined with increasing levels of sediment disturbance, counter to the disturbance-invasion hypothesis. Increased sediment disturbance by the urchins also reduced the richness and diversity of native macrofauna (particularly small, sedentary, surface feeders), though there was no evidence of increased availability of resources with increased disturbance that would have facilitated invasive colonization: sediment food resources (chlorophyll a and organic matter content) did not increase, and space and access to overlying water were not limited (low invertebrate abundance). Thus, our study revealed the importance of biogenic disturbance in promoting invasion resistance in a marine soft-sediment community, providing further evidence of the valuable role of bioturbation in soft-sediment systems (bioturbation also affects carbon processing, nutrient recycling, oxygen dynamics, benthic community structure, and so on.). Bioturbation rates are

  12. MSX2 Induces Trophoblast Invasion in Human Placenta

    PubMed Central

    Lu, Junjie; Yang, Genling; Tian, Na; Wang, Xiaojie; Tan, Yi; Tan, Dongmei

    2016-01-01

    Normal implantation depends on appropriate trophoblast growth and invasion. Inadequate trophoblast invasion results in pregnancy-related disorders, such as early miscarriage and pre-eclampsia, which are dangerous to both the mother and fetus. Msh Homeobox 2 (MSX2), a member of the MSX family of homeobox proteins, plays a significant role in the proliferation and differentiation of various cells and tissues, including ectodermal organs, teeth, and chondrocytes. Recently, MSX2 was found to play important roles in the invasion of cancer cells into adjacent tissues via the epithelial-mesenchymal transition (EMT). However, the role of MSX2 in trophoblastic invasion during placental development has yet to be explored. In the present study, we detected MSX2 expression in cytotrophoblast, syncytiotrophoblast, and extravillous cytotrophoblast cells of first or third trimester human placentas via immunohistochemistry analysis. Furthermore, we found that the in vitro invasive ability of HTR8/SVneo cells was enhanced by exogenous overexpression of MSX2, and that this effect was accompanied by increased protein expression of matrix metalloproteinase-2 (MMP-2), vimentin, and β-catenin. Conversely, treatment of HTR8/SVneo cells with MSX2-specific siRNAs resulted in decreased protein expression of MMP-2, vimentin, and β-catenin, and reduced invasion levels in a Matrigel invasion test. Notably, however, treatment with the MSX2 overexpression plasmid and the MSX2 siRNAs had no effect on the mRNA expression levels of β-catenin. Meanwhile, overexpression of MSX2 and treatment with the MSX2-specific siRNA resulted in decreased and increased E-cadherin expression, respectively, in JEG-3 cells. Lastly, the protein expression levels of MSX2 were significantly lower in human pre-eclamptic placental villi than in the matched control placentas. Collectively, our results suggest that MSX2 may induce human trophoblast cell invasion, and dysregulation of MSX2 expression may be associated

  13. Out of the Black Sea: Phylogeography of the Invasive Killer Shrimp Dikerogammarus villosus across Europe

    PubMed Central

    Rewicz, Tomasz; Wattier, Remi; Grabowski, Michał; Rigaud, Thierry; Bącela-Spychalska, Karolina

    2015-01-01

    The amphipod Dikerogammarus villosus has colonized most of the European main inland water bodies in less than 20 years, having deteriorating effect on the local benthic communities. Our aim was to reveal the species phylogeography in the native Black Sea area, to define the source populations for the colonization routes in continental Europe and for the newly established UK populations. We tested for the loss of genetic diversity between source and invasive populations as well as along invasion route. We tested also for isolation by distance. Thirty three native and invasive populations were genotyped for mtDNA (COI, 16S) and seven polymorphic nuclear microsatellites to assess cryptic diversity (presence of deeply divergent lineages), historical demography, level of diversity within lineage (e.g., number of alleles), and population structure. A wide range of methods was used, including minimum spanning network, molecular clock, Bayesian clustering and Mantel test. Our results identified that sea level and salinity changes during Pleistocene impacted the species phylogeography in the Black Sea native region with four differentiated populations inhabiting, respectively, the Dnieper, Dniester, Danube deltas and Durungol liman. The invasion of continental Europe is associated with two sources, i.e., the Danube and Dnieper deltas, which gave origin to two independent invasion routes (Western and Eastern) for which no loss of diversity and no isolation by distance were observed. The UK population has originated in the Western Route and, despite very recent colonization, no drastic loss of diversity was observed. The results show that the invasion of the killer shrimp is not associated with the costs of loosing genetic diversity, which may contribute to the success of this invader in the newly colonized areas. Additionally, while it has not yet occurred, it might be expected that future interbreeding between the genetically diversified populations from two independent

  14. Transanal Minimally Invasive Surgery

    PubMed Central

    deBeche-Adams, Teresa; Nassif, George

    2015-01-01

    Transanal minimally invasive surgery (TAMIS) was first described in 2010 as a crossover between single-incision laparoscopic surgery and transanal endoscopic microsurgery (TEM) to allow access to the proximal and mid-rectum for resection of benign and early-stage malignant rectal lesions. The TAMIS technique can also be used for noncurative intent surgery of more advanced lesions in patients who are not candidates for radical surgery. Proper workup and staging should be done before surgical decision-making. In addition to the TAMIS port, instrumentation and set up include readily available equipment found in most operating suites. TAMIS has proven its usefulness in a wide range of applications outside of local excision, including repair of rectourethral fistula, removal of rectal foreign body, control of rectal hemorrhage, and as an adjunct in total mesorectal excision for rectal cancer. TAMIS is an easily accessible, technically feasible, and cost-effective alternative to TEM. PMID:26491410

  15. [Minimal invasive implantology].

    PubMed

    Bruck, N; Zagury, A; Nahlieli, O

    2015-07-01

    Endoscopic surgery has changed the philosophy and practice of modern surgery in all aspects of medicine. It gave rise to minimally invasive surgery procedures based on the ability to visualize and to operate via small channels. In maxillofacial surgery, our ability to see clearly the surgical field opened an entirely new world of exploration, as conditions that were once almost impossible to control and whose outcome was uncertain can be now predictably managed. in this article we will descripe the advantage of using the oral endoscope during the dental implantology procedure, and we will describe a unique implant which enable us in combination with the oral endoscope to create a maxillary sinus lift with out the need of the major surgery with all of its risks and complication.

  16. [Minimally invasive breast surgery].

    PubMed

    Mátrai, Zoltán; Gulyás, Gusztáv; Kunos, Csaba; Sávolt, Akos; Farkas, Emil; Szollár, András; Kásler, Miklós

    2014-02-01

    Due to the development in medical science and industrial technology, minimally invasive procedures have appeared in the surgery of benign and malignant breast diseases. In general , such interventions result in significantly reduced breast and chest wall scars, shorter hospitalization and less pain, but they require specific, expensive devices, longer surgical time compared to open surgery. Furthermore, indications or oncological safety have not been established yet. It is quite likely, that minimally invasive surgical procedures with high-tech devices - similar to other surgical subspecialties -, will gradually become popular and it may form part of routine breast surgery even. Vacuum-assisted core biopsy with a therapeutic indication is suitable for the removal of benign fibroadenomas leaving behind an almost invisible scar, while endoscopically assisted skin-sparing and nipple-sparing mastectomy, axillary staging and reconstruction with latissimus dorsi muscle flap are all feasible through the same short axillary incision. Endoscopic techniques are also suitable for the diagnostics and treatment of intracapsular complications of implant-based breast reconstructions (intracapsular fluid, implant rupture, capsular contracture) and for the biopsy of intracapsular lesions with uncertain pathology. Perception of the role of radiofrequency ablation of breast tumors requires further hands-on experience, but it is likely that it can serve as a replacement of surgical removal in a portion of primary tumors in the future due to the development in functional imaging and anticancer drugs. With the reduction of the price of ductoscopes routine examination of the ductal branch system, guided microdochectomy and targeted surgical removal of terminal ducto-lobular units or a "sick lobe" as an anatomical unit may become feasible. The paper presents the experience of the authors and provides a literature review, for the first time in Hungarian language on the subject. Orv. Hetil

  17. Spread dynamics of invasive species

    PubMed Central

    Arim, Matías; Abades, Sebastián R.; Neill, Paula E.; Lima, Mauricio; Marquet, Pablo A.

    2006-01-01

    Species invasions are a principal component of global change, causing large losses in biodiversity as well as economic damage. Invasion theory attempts to understand and predict invasion success and patterns of spread. However, there is no consensus regarding which species or community attributes enhance invader success or explain spread dynamics. Experimental and theoretical studies suggest that regulation of spread dynamics is possible; however, the conditions for its existence have not yet been empirically demonstrated. If invasion spread is a regulated process, the structure that accounts for this regulation will be a main determinant of invasion dynamics. Here we explore the existence of regulation underlying changes in the rate of new site colonization. We employ concepts and analytical tools from the study of abundance dynamics and show that spread dynamics are, in fact, regulated processes and that the regulation structure is notably consistent among invasions occurring in widely different contexts. We base our conclusions on the analysis of the spread dynamics of 30 species invasions, including birds, amphibians, fish, invertebrates, plants, and a virus, all of which exhibited similar regulation structures. In contrast to current beliefs that species invasions are idiosyncratic phenomena, here we provide evidence that general patterns do indeed exist. PMID:16387862

  18. Integrated assessment of biological invasions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    As the main annalists of the ecological and economic impacts of invasions on ecosystems around the world, ecologists should be able to provide information that can guide management practices. Managers often want to know about the potential for invasion of specific organisms in the sites under their ...

  19. Neural invasion in gastric carcinoma.

    PubMed Central

    Mori, M; Adachi, Y; Kamakura, T; Ikeda, Y; Maehara, Y; Sugimachi, K

    1995-01-01

    AIMS--To determine whether neural invasion in advanced gastric cancer is of clinicopathological significance. METHODS--The study population comprised 121 cases of primary advanced gastric carcinoma. Two paraffin wax embedded blocks taken from the central tissue slice in each primary tumour were used. For definitive recognition of neural invasion, immunostaining for S-100 protein was applied to one slide; the other slide was stained with haematoxylin and eosin. RESULTS--Neural invasion was recognised in 34 of 121 (28%) primary gastric carcinomas. There were significant differences in tumour size, depth of tumour invasion, stage, and curability between patients with and without neural invasion. The five year survival rates of patients with and without neural invasion were 10 and 50%, respectively. Multivariate analysis, however, demonstrated that neural invasion was not an independent prognostic factor. CONCLUSIONS--Neural invasion could be an additional useful factor for providing information about the malignant potential of gastric carcinoma. This may be analogous to vessel permeation which is thought to be important, but is not an independent prognostic factor. Images PMID:7745113

  20. Prioritizing invasive plant management strategies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Invasive plants are seriously impacting rangelands by displacing desirable species. Management of these species is expensive and careful allocation of scarce dollars is necessary. Ecologically-based invasive plant management (EBIPM) has the potential to provide an improved decision-making process ...

  1. Update on the management of invasive bladder cancer 2012

    PubMed Central

    Goethuys, Hans; Van Poppel, Hein

    2012-01-01

    Muscle-invasive bladder cancer is a deadly disease for which a number of new approaches have become available to improve prognosis. A recent review emphasized the importance of timely indication of surgery and highlighted current views regarding the adequate extent of the surgery and the importance of lymph node dissection. Furthermore, treatment using neoadjuvant and adjuvant systemic chemotherapy has become more prominent, while cystectomy and diversion should be conducted only in experienced centers. Optimal methods of urinary diversion and the use of robot-assisted laparoscopic cystectomy require further study. PMID:22904639

  2. Drosophila suzukii: The Genetic Footprint of a Recent, Worldwide Invasion

    PubMed Central

    Adrion, Jeffrey R.; Kousathanas, Athanasios; Pascual, Marta; Burrack, Hannah J.; Haddad, Nick M.; Bergland, Alan O.; Machado, Heather; Sackton, Timothy B.; Schlenke, Todd A.; Watada, Masayoshi; Wegmann, Daniel; Singh, Nadia D.

    2014-01-01

    Native to Asia, the soft-skinned fruit pest Drosophila suzukii has recently invaded the United States and Europe. The eastern United States represents the most recent expansion of their range, and presents an opportunity to test alternative models of colonization history. Here, we investigate the genetic population structure of this invasive fruit fly, with a focus on the eastern United States. We sequenced six X-linked gene fragments from 246 individuals collected from a total of 12 populations. We examine patterns of genetic diversity within and between populations and explore alternative colonization scenarios using approximate Bayesian computation. Our results indicate high levels of nucleotide diversity in this species and suggest that the recent invasions of Europe and the continental United States are independent demographic events. More broadly speaking, our results highlight the importance of integrating population structure into demographic models, particularly when attempting to reconstruct invasion histories. Finally, our simulation results illustrate the general challenge in reconstructing invasion histories using genetic data and suggest that genome-level data are often required to distinguish among alternative demographic scenarios. PMID:25158796

  3. Src Kinase Regulation in Progressively Invasive Cancer

    PubMed Central

    Xu, Weichen; Allbritton, Nancy; Lawrence, David S.

    2012-01-01

    Metastatic progression is a multistep process that involves tumor growth and survival, motility and invasion, and subsequent proliferation in an inappropriate environment. The Src protein tyrosine kinase has been implicated in many of the biochemical pathways that drive these behaviors. Although Src itself is only rarely mutated in human tumors, its aberrant activity has been noted in various cancers and suggested to serve as a barometer of metastatic potential. With these features in mind, we examined Src kinase regulation at the structural, enzymatic, and expression levels as a function of progressively invasive prostate cancer cell lines. Surprisingly, both total Src content and kinase activity decrease with increasing cell line aggressiveness, an observation that appears to be inconsistent with the well-documented role of Src in the signaling pathways that drive growth and invasion. However, we do observe a direct correlation between Src kinase specific activity (total Src kinase activity/total Src content) and metastatic aggressiveness, possibly suggesting that in highly aggressive cell lines, key signaling enzymes are globally recruited to drive the cancerous phenotype. In addition, although the expected enhanced phosphorylation of Src at Tyr-416 (activation site) is present in the most aggressive prostate cancer cell lines, unexpectedly high phosphorylation levels at the Tyr-527 inhibitory site are observed as well. The latter, rather than representative of inhibited enzyme, is more indicative of primed Src responsive to local phosphorylated binding partners. PMID:23145001

  4. Gypenosides inhibits migration and invasion of human oral cancer SAS cells through the inhibition of matrix metalloproteinase-2 -9 and urokinase-plasminogen by ERK1/2 and NF-kappa B signaling pathways.

    PubMed

    Lu, Kung-Wen; Chen, Jung-Chou; Lai, Tung-Yuan; Yang, Jai-Sing; Weng, Shu-Wen; Ma, Yi-Shih; Lu, Pei-Jung; Weng, Jing-Ru; Chueh, Fu-Shin; Wood, W Gibson; Chung, Jing-Gung

    2011-05-01

    Gypenosides (Gyp), found in Gynostemma pentaphyllum Makino, has been used as a folk medicine in the Chinese population for centuries and is known to have diverse pharmacologic effects, including anti-proliferative and anti-cancer actions. However, the effects of Gyp on prevention from invasion and migration of oral cancer cells are still unsatisfactory. The purpose of this study was to investigate effects of Gyp treatment on migration and invasion of SAS human oral cancer cells. SAS cells were cultured in the presence of 90 and 180 μg/mL Gyp for 24 and 48 hours. Gyp induced cytotoxic effects and inhibited SAS cells migration and invasion in dose- and time-dependent response. Wound-healing assay and boyden chamber assay were carried out to investigate Gyp-inhibited migration and invasion of SAS cells. Gyp decreased the abundance of several proteins, including nuclear factor-kappa B (NF-κB), cyclooxygenase-2 (COX-2), extracellular signal-regulated kinase 1/2 (ERK1/ 2), matrix metalloproteinase-9, -2 (MMP-9, -2), sevenless homolog (SOS), Ras, urokinase-type plasminogen activator (uPA), focal adhesion kinase (FAK) and RAC-alpha serine/threonine-protein kinase (Akt), in a time-dependent manner. In addition, Gyp decreased mRNA levels of MMP-2, MMP-7, MMP-9 but did not affect FAK and Rho A mRNA levels in SAS cells. These results provide evidences for the role of Gyp as a potent anti-metastatic agent, which can markedly inhibit the metastatic and invasive capacity of oral cancer cells. The inhibition of NF-κB and MMP-2, -7 and -9 signaling may be one of the mechanisms that is present in Gyp-inhibited cancer cell invasion and migration.

  5. Cannabidiol inhibits cancer cell invasion via upregulation of tissue inhibitor of matrix metalloproteinases-1.

    PubMed

    Ramer, Robert; Merkord, Jutta; Rohde, Helga; Hinz, Burkhard

    2010-04-01

    Although cannabinoids exhibit a broad variety of anticarcinogenic effects, their potential use in cancer therapy is limited by their psychoactive effects. Here we evaluated the impact of cannabidiol, a plant-derived non-psychoactive cannabinoid, on cancer cell invasion. Using Matrigel invasion assays we found a cannabidiol-driven impaired invasion of human cervical cancer (HeLa, C33A) and human lung cancer cells (A549) that was reversed by antagonists to both CB(1) and CB(2) receptors as well as to transient receptor potential vanilloid 1 (TRPV1). The decrease of invasion by cannabidiol appeared concomitantly with upregulation of tissue inhibitor of matrix metalloproteinases-1 (TIMP-1). Knockdown of cannabidiol-induced TIMP-1 expression by siRNA led to a reversal of the cannabidiol-elicited decrease in tumor cell invasiveness, implying a causal link between the TIMP-1-upregulating and anti-invasive action of cannabidiol. P38 and p42/44 mitogen-activated protein kinases were identified as upstream targets conferring TIMP-1 induction and subsequent decreased invasiveness. Additionally, in vivo studies in thymic-aplastic nude mice revealed a significant inhibition of A549 lung metastasis in cannabidiol-treated animals as compared to vehicle-treated controls. Altogether, these findings provide a novel mechanism underlying the anti-invasive action of cannabidiol and imply its use as a therapeutic option for the treatment of highly invasive cancers.

  6. Inhibition between invasives: a newly introduced predator moderates the impacts of a previously established invasive predator.

    PubMed

    Griffen, Blaine D; Guy, Travis; Buck, Julia C

    2008-01-01

    1. With continued globalization, species are being transported and introduced into novel habitats at an accelerating rate. Interactions between invasive species may provide important mechanisms that moderate their impacts on native species. 2. The European green crab Carcinus maenas is an aggressive predator that was introduced to the east coast of North America in the mid-1800 s and is capable of rapid consumption of bivalve prey. A newer invasive predator, the Asian shore crab Hemigrapsus sanguineus, was first discovered on the Atlantic coast in the 1980s, and now inhabits many of the same regions as C. maenas within the Gulf of Maine. Using a series of field and laboratory investigations, we examined the consequences of interactions between these predators. 3. Density patterns of these two species at different spatial scales are consistent with negative interactions. As a result of these interactions, C. maenas alters its diet to consume fewer mussels, its preferred prey, in the presence of H. sanguineus. Decreased mussel consumption in turn leads to lower growth rates for C. maenas, with potential detrimental effects on C. maenas populations. 4. Rather than an invasional meltdown, this study demonstrates that, within the Gulf of Maine, this new invasive predator can moderate the impacts of the older invasive predator.

  7. Inhibition between invasives: a newly introduced predator moderates the impacts of a previously established invasive predator.

    PubMed

    Griffen, Blaine D; Guy, Travis; Buck, Julia C

    2008-01-01

    1. With continued globalization, species are being transported and introduced into novel habitats at an accelerating rate. Interactions between invasive species may provide important mechanisms that moderate their impacts on native species. 2. The European green crab Carcinus maenas is an aggressive predator that was introduced to the east coast of North America in the mid-1800 s and is capable of rapid consumption of bivalve prey. A newer invasive predator, the Asian shore crab Hemigrapsus sanguineus, was first discovered on the Atlantic coast in the 1980s, and now inhabits many of the same regions as C. maenas within the Gulf of Maine. Using a series of field and laboratory investigations, we examined the consequences of interactions between these predators. 3. Density patterns of these two species at different spatial scales are consistent with negative interactions. As a result of these interactions, C. maenas alters its diet to consume fewer mussels, its preferred prey, in the presence of H. sanguineus. Decreased mussel consumption in turn leads to lower growth rates for C. maenas, with potential detrimental effects on C. maenas populations. 4. Rather than an invasional meltdown, this study demonstrates that, within the Gulf of Maine, this new invasive predator can moderate the impacts of the older invasive predator. PMID:18177327

  8. Does natural variation in diversity affect biotic resistance?

    USGS Publications Warehouse

    Harrison, Susan; Cornell, Howard; Grace, James B.

    2015-01-01

    Theories linking diversity to ecosystem function have been challenged by the widespread observation of more exotic species in more diverse native communities. Few studies have addressed the key underlying process by dissecting how community diversity is shaped by the same environmental gradients that determine biotic and abiotic resistance to new invaders. In grasslands on highly heterogeneous soils, we used addition of a recent invader, competitor removal and structural equation modelling (SEM) to analyse soil influences on community diversity, biotic and abiotic resistance and invader success. Biotic resistance, measured by reduction in invader success in the presence of the resident community, was negatively correlated with species richness and functional diversity. However, in the multivariate SEM framework, biotic resistance was independent of all forms of diversity and was positively affected by soil fertility via community biomass. Abiotic resistance, measured by invader success in the absence of the resident community, peaked on infertile soils with low biomass and high community diversity. Net invader success was determined by biotic resistance, consistent with this invader's better performance on infertile soils in unmanipulated conditions. Seed predation added slightly to biotic resistance without qualitatively changing the results. Soil-related genotypic variation in the invader also did not affect the results. Synthesis. In natural systems, diversity may be correlated with invasibility and yet have no effect on either biotic or abiotic resistance to invasion. More generally, the environmental causes of variation in diversity should not be overlooked when considering the potential functional consequences of diversity.

  9. Diverse Classrooms, Diverse Curriculum, Diverse Complications: Three Teacher Perspectives

    ERIC Educational Resources Information Center

    Ungemah, Lori D.

    2015-01-01

    Racial, ethnic, linguistic, and religious diversity continues to increase in classrooms. Many call for a more diverse curriculum, but curricular diversity brings its own challenges to both teachers and students. These three vignettes are drawn from my ethnographic data at Atlantic High School in Brooklyn, New York, where I worked for ten years as…

  10. Cell polarity signaling in the plasticity of cancer cell invasiveness.

    PubMed

    Gandalovičová, Aneta; Vomastek, Tomáš; Rosel, Daniel; Brábek, Jan

    2016-05-01

    Apico-basal polarity is typical of cells present in differentiated epithelium while front-rear polarity develops in motile cells. In cancer development, the transition from epithelial to migratory polarity may be seen as the hallmark of cancer progression to an invasive and metastatic disease. Despite the morphological and functional dissimilarity, both epithelial and migratory polarity are controlled by a common set of polarity complexes Par, Scribble and Crumbs, phosphoinositides, and small Rho GTPases Rac, Rho and Cdc42. In epithelial tissues, their mutual interplay ensures apico-basal and planar cell polarity. Accordingly, altered functions of these polarity determinants lead to disrupted cell-cell adhesions, cytoskeleton rearrangements and overall loss of epithelial homeostasis. Polarity proteins are further engaged in diverse interactions that promote the establishment of front-rear polarity, and they help cancer cells to adopt different invasion modes. Invading cancer cells can employ either the collective, mesenchymal or amoeboid invasion modes or actively switch between them and gain intermediate phenotypes. Elucidation of the role of polarity proteins during these invasion modes and the associated transitions is a necessary step towards understanding the complex problem of metastasis. In this review we summarize the current knowledge of the role of cell polarity signaling in the plasticity of cancer cell invasiveness.

  11. Cell polarity signaling in the plasticity of cancer cell invasiveness

    PubMed Central

    Gandalovičová, Aneta; Vomastek, Tomáš; Rosel, Daniel; Brábek, Jan

    2016-01-01

    Apico-basal polarity is typical of cells present in differentiated epithelium while front-rear polarity develops in motile cells. In cancer development, the transition from epithelial to migratory polarity may be seen as the hallmark of cancer progression to an invasive and metastatic disease. Despite the morphological and functional dissimilarity, both epithelial and migratory polarity are controlled by a common set of polarity complexes Par, Scribble and Crumbs, phosphoinositides, and small Rho GTPases Rac, Rho and Cdc42. In epithelial tissues, their mutual interplay ensures apico-basal and planar cell polarity. Accordingly, altered functions of these polarity determinants lead to disrupted cell-cell adhesions, cytoskeleton rearrangements and overall loss of epithelial homeostasis. Polarity proteins are further engaged in diverse interactions that promote the establishment of front-rear polarity, and they help cancer cells to adopt different invasion modes. Invading cancer cells can employ either the collective, mesenchymal or amoeboid invasion modes or actively switch between them and gain intermediate phenotypes. Elucidation of the role of polarity proteins during these invasion modes and the associated transitions is a necessary step towards understanding the complex problem of metastasis. In this review we summarize the current knowledge of the role of cell polarity signaling in the plasticity of cancer cell invasiveness. PMID:26872368

  12. An ideal weed: plasticity and invasiveness in Polygonum cespitosum.

    PubMed

    Sultan, Sonia E; Matesanz, Silvia

    2015-12-01

    The introduced Asian plant Polygonum cespitosum has only recently become invasive in northeastern North America, spreading into sunny as well as shaded habitats. We present findings from a multiyear case study of this ongoing species invasion, drawing on field environmental measurements, glasshouse plasticity and resurrection experiments, and molecular genetic (microsatellite) data. We focus in particular on patterns of individual phenotypic plasticity (norms of reaction), their diversity within and among populations in the species' introduced range, and their contribution to its potential to evolve even greater invasiveness. Genotypes from introduced-range P. cespitosum populations have recently evolved to express greater adaptive plasticity to full sun and/or dry conditions without any loss of fitness in shade. Evidently, this species may evolve the sort of "general-purpose genotypes" hypothesized by Herbert Baker to characterize an "ideal weed." Indeed, we identified certain genotypes capable of extremely high reproductive output across contrasting conditions, including sunny, shaded, moist, and dry. Populations containing these high-performance genotypes had consistently higher fitness in all glasshouse habitats; there was no evidence for local adaptive differentiation among populations from sunny, shaded, moist, or dry sites. Norm of reaction data may provide valuable insights to invasion biology: the presence of broadly adaptive, high-performance genotypes can promote a species' ecological spread while providing the fuel for increased invasiveness to evolve. PMID:26457473

  13. No evolution of increased competitive ability or decreased allocation to defense in Melaleuca quinquenervia since release from natural enemies

    Technology Transfer Automated Retrieval System (TEKTRAN)

    If invasive plants are released from natural enemies in their introduced range, they may evolve decreased allocation to defense and increased growth, as predicted by the evolution of increased competitive ability (EICA) hypothesis. A field experiment using the invasive tree Melaleuca quinquenervia ...

  14. High genetic diversity is not essential for successful introduction

    PubMed Central

    Rollins, Lee A; Moles, Angela T; Lam, Serena; Buitenwerf, Robert; Buswell, Joanna M; Brandenburger, Claire R; Flores-Moreno, Habacuc; Nielsen, Knud B; Couchman, Ellen; Brown, Gordon S; Thomson, Fiona J; Hemmings, Frank; Frankham, Richard; Sherwin, William B

    2013-01-01

    Some introduced populations thrive and evolve despite the presumed loss of diversity at introduction. We aimed to quantify the amount of genetic diversity retained at introduction in species that have shown evidence of adaptation to their introduced environments. Samples were taken from native and introduced ranges of Arctotheca populifolia and Petrorhagia nanteuilii. Using microsatellite data, we identified the source for each introduction, estimated genetic diversity in native and introduced populations, and calculated the amount of diversity retained in introduced populations. These values were compared to those from a literature review of diversity in native, confamilial populations and to estimates of genetic diversity retained at introduction. Gene diversity in the native range of both species was significantly lower than for confamilials. We found that, on average, introduced populations showing evidence of adaptation to their new environments retained 81% of the genetic diversity from the native range. Introduced populations of P. nanteuilii had higher genetic diversity than found in the native source populations, whereas introduced populations of A. populifolia retained only 14% of its native diversity in one introduction and 1% in another. Our literature review has shown that most introductions demonstrating adaptive ability have lost diversity upon introduction. The two species studied here had exceptionally low native range genetic diversity. Further, the two introductions of A. populifolia represent the largest percentage loss of genetic diversity in a species showing evidence of substantial morphological change in the introduced range. While high genetic diversity may increase the likelihood of invasion success, the species examined here adapted to their new environments with very little neutral genetic diversity. This finding suggests that even introductions founded by small numbers of individuals have the potential to become invasive. PMID:24340190

  15. A global indicator for biological invasion.

    PubMed

    McGeoch, Melodie A; Chown, Steven L; Kalwij, Jesse M

    2006-12-01

    "Trends in invasive alien species" is one of only two indicators of threat to biodiversity that form part of the Convention on Biological Diversity's (CBD) framework for monitoring progress toward its "2010 target" (i.e., the commitment to achieve by 2010 a significant reduction in the current rate of biodiversity loss). To date, however, there is no fully developed indicator for invasive alien species (IAS) that combines trends, derived from a standard set of methods, across species groups, ecosystems, and regions. Here we provide a rationale for the form and characteristics of an indicator of trends in IAS that will meet the 2010 framework goal and targets for this indicator. We suggest single and composite indicators that include problem-status and management-status measures that are designed to be flexible, readily disaggregated, and as far as possible draw on existing data. The single indicators at national and global scales are number of IAS and numbers of operational management plans for IAS. Global trends in IAS are measured as the progress of nations toward the targets of stabilizing IAS numbers and the implementation of IAS management plans. The proposed global indicator thus represents a minimum information set that most directly addresses the indicator objective and simultaneously aims to maximize national participation. This global indicator now requires testing to assess its accuracy, sensitivity, and tractability. Although it may not be possible to achieve the desired objective for a global indicator of biological invasion by 2010 as comprehensively as desired, it seems possible to obtain trend estimates for a component of the taxa, ecosystems, and regions involved. Importantly, current indicator development initiatives will also contribute to developing the mechanisms necessary for monitoring global trends in IAS beyond 2010.

  16. Detrimental Influence of Invasive Earthworms on North American Cold-Temperate Forest Soils

    ERIC Educational Resources Information Center

    Enerson, Isabel

    2012-01-01

    The topic of invasive earthworms is a timely concern that goes against many preconceived notions regarding the positive benefits of all worms. In the cold-temperate forests of North America invasive worms are threatening forest ecosystems, due to the changes they create in the soil, including decreases in C:N ratios and leaf litter, disruption of…

  17. Solar-wind velocity decreases

    NASA Astrophysics Data System (ADS)

    Geranios, A.

    1980-08-01

    A model is developed to account for the solar wind electron and proton temperature decreases observed following the passage of an interplanetary shock wave and during the velocity decrease of a solar wind stream. The equations of mass and energy conservation are solved for a fully ionized, electrically neutral plasma expanding radially and spherically symmetrically, taking into account the heat flux from the solor corona to the plasma along the open magnetic field lines, and the electron thermal conductivity. An analytical relationship between the temperature and the velocity of the solar wind plasma is obtained which is found to be in agreement with experimental measurements made by the Vela 5 and 6 and IMP 6 satellites from August 1969-May 1974. It is thus proposed that the observed low plasma temperatures are due to the fact that the temperature decrease of the expanding plasma exceeds the heat gain due to thermal conduction from the corona.

  18. Plant functional traits of dominant native and invasive species in mediterranean-climate ecosystems.

    PubMed

    Funk, Jennifer L; Standish, Rachel J; Stock, William D; Valladares, Fernando

    2016-01-01

    The idea that dominant invasive plant species outperform neighboring native species through higher rates of carbon assimilation and growth is supported by several analyses of global data sets. However, theory suggests that native and invasive species occurring in low-resource environments will be functionally similar, as environmental factors restrict the range of observed physiological and morphological trait values. We measured resource-use traits in native and invasive plant species across eight diverse vegetation communities distributed throughout the five mediterranean-climate regions, which are drought prone and increasingly threatened by human activities, including the introduction of exotic species. Traits differed strongly across the five regions. In regions with functional differences between native and invasive species groups, invasive species displayed traits consistent with high resource acquisition; however, these patterns were largely attributable to differences in life form. We found that species invading mediterranean-climate regions were more likely to be annual than perennial: three of the five regions were dominated by native woody species and invasive annuals. These results suggest that trait differences between native and invasive species are context dependent and will vary across vegetation communities. Native and invasive species within annual and perennial groups had similar patterns of carbon assimilation and resource use, which contradicts the widespread idea that invasive species optimize resource acquisition rather than resource conservation. . PMID:27008777

  19. Plant functional traits of dominant native and invasive species in mediterranean-climate ecosystems.

    PubMed

    Funk, Jennifer L; Standish, Rachel J; Stock, William D; Valladares, Fernando

    2016-01-01

    The idea that dominant invasive plant species outperform neighboring native species through higher rates of carbon assimilation and growth is supported by several analyses of global data sets. However, theory suggests that native and invasive species occurring in low-resource environments will be functionally similar, as environmental factors restrict the range of observed physiological and morphological trait values. We measured resource-use traits in native and invasive plant species across eight diverse vegetation communities distributed throughout the five mediterranean-climate regions, which are drought prone and increasingly threatened by human activities, including the introduction of exotic species. Traits differed strongly across the five regions. In regions with functional differences between native and invasive species groups, invasive species displayed traits consistent with high resource acquisition; however, these patterns were largely attributable to differences in life form. We found that species invading mediterranean-climate regions were more likely to be annual than perennial: three of the five regions were dominated by native woody species and invasive annuals. These results suggest that trait differences between native and invasive species are context dependent and will vary across vegetation communities. Native and invasive species within annual and perennial groups had similar patterns of carbon assimilation and resource use, which contradicts the widespread idea that invasive species optimize resource acquisition rather than resource conservation. .

  20. A Source Area Approach Demonstrates Moderate Predictive Ability but Pronounced Variability of Invasive Species Traits.

    PubMed

    Klonner, Günther; Fischer, Stefan; Essl, Franz; Dullinger, Stefan

    2016-01-01

    The search for traits that make alien species invasive has mostly concentrated on comparing successful invaders and different comparison groups with respect to average trait values. By contrast, little attention has been paid to trait variability among invaders. Here, we combine an analysis of trait differences between invasive and non-invasive species with a comparison of multidimensional trait variability within these two species groups. We collected data on biological and distributional traits for 1402 species of the native, non-woody vascular plant flora of Austria. We then compared the subsets of species recorded and not recorded as invasive aliens anywhere in the world, respectively, first, with respect to the sampled traits using univariate and multiple regression models; and, second, with respect to their multidimensional trait diversity by calculating functional richness and dispersion metrics. Attributes related to competitiveness (strategy type, nitrogen indicator value), habitat use (agricultural and ruderal habitats, occurrence under the montane belt), and propagule pressure (frequency) were most closely associated with invasiveness. However, even the best multiple model, including interactions, only explained a moderate fraction of the differences in invasive success. In addition, multidimensional variability in trait space was even larger among invasive than among non-invasive species. This pronounced variability suggests that invasive success has a considerable idiosyncratic component and is probably highly context specific. We conclude that basing risk assessment protocols on species trait profiles will probably face hardly reducible uncertainties.

  1. A Source Area Approach Demonstrates Moderate Predictive Ability but Pronounced Variability of Invasive Species Traits

    PubMed Central

    Essl, Franz; Dullinger, Stefan

    2016-01-01

    The search for traits that make alien species invasive has mostly concentrated on comparing successful invaders and different comparison groups with respect to average trait values. By contrast, little attention has been paid to trait variability among invaders. Here, we combine an analysis of trait differences between invasive and non-invasive species with a comparison of multidimensional trait variability within these two species groups. We collected data on biological and distributional traits for 1402 species of the native, non-woody vascular plant flora of Austria. We then compared the subsets of species recorded and not recorded as invasive aliens anywhere in the world, respectively, first, with respect to the sampled traits using univariate and multiple regression models; and, second, with respect to their multidimensional trait diversity by calculating functional richness and dispersion metrics. Attributes related to competitiveness (strategy type, nitrogen indicator value), habitat use (agricultural and ruderal habitats, occurrence under the montane belt), and propagule pressure (frequency) were most closely associated with invasiveness. However, even the best multiple model, including interactions, only explained a moderate fraction of the differences in invasive success. In addition, multidimensional variability in trait space was even larger among invasive than among non-invasive species. This pronounced variability suggests that invasive success has a considerable idiosyncratic component and is probably highly context specific. We conclude that basing risk assessment protocols on species trait profiles will probably face hardly reducible uncertainties. PMID:27187616

  2. A Source Area Approach Demonstrates Moderate Predictive Ability but Pronounced Variability of Invasive Species Traits.

    PubMed

    Klonner, Günther; Fischer, Stefan; Essl, Franz; Dullinger, Stefan

    2016-01-01

    The search for traits that make alien species invasive has mostly concentrated on comparing successful invaders and different comparison groups with respect to average trait values. By contrast, little attention has been paid to trait variability among invaders. Here, we combine an analysis of trait differences between invasive and non-invasive species with a comparison of multidimensional trait variability within these two species groups. We collected data on biological and distributional traits for 1402 species of the native, non-woody vascular plant flora of Austria. We then compared the subsets of species recorded and not recorded as invasive aliens anywhere in the world, respectively, first, with respect to the sampled traits using univariate and multiple regression models; and, second, with respect to their multidimensional trait diversity by calculating functional richness and dispersion metrics. Attributes related to competitiveness (strategy type, nitrogen indicator value), habitat use (agricultural and ruderal habitats, occurrence under the montane belt), and propagule pressure (frequency) were most closely associated with invasiveness. However, even the best multiple model, including interactions, only explained a moderate fraction of the differences in invasive success. In addition, multidimensional variability in trait space was even larger among invasive than among non-invasive species. This pronounced variability suggests that invasive success has a considerable idiosyncratic component and is probably highly context specific. We conclude that basing risk assessment protocols on species trait profiles will probably face hardly reducible uncertainties. PMID:27187616

  3. Interactions between abiotic constraint, propagule pressure, and biotic resistance regulate plant invasion.

    PubMed

    Byun, Chaeho; de Blois, Sylvie; Brisson, Jacques

    2015-05-01

    With multiple species introductions and rapid global changes, there is a need for comprehensive invasion models that can predict community responses. Evidence suggests that abiotic constraint, propagule pressure, and biotic resistance of resident species each determine plant invasion success, yet their interactions are rarely tested. To understand these interactions, we conducted community assembly experiments simulating situations in which seeds of the invasive grass species Phragmites australis (Poaceae) land on bare soil along with seeds of resident wetland plant species. We used structural equation models to measure both direct abiotic constraint (here moist vs. flooded conditions) on invasion success and indirect constraint on the abundance and, therefore, biotic resistance of resident plant species. We also evaluated how propagule supply of P. australis interacts with the biotic resistance of resident species during invasion. We observed that flooding always directly reduced invasion success but had a synergistic or antagonistic effect on biotic resistance depending on the resident species involved. Biotic resistance of the most diverse resident species mixture remained strong even when abiotic conditions changed. Biotic resistance was also extremely effective under low propagule pressure of the invader. Moreover, the presence of a dense resident plant cover appeared to lower the threshold at which invasion success became stable even when propagule supply increased. Our study not only provides an analytical framework to quantify the effect of multiple interactions relevant to community assembly and species invasion, but it also proposes guidelines for innovative invasion management strategies based on a sound understanding of ecological processes.

  4. Invasive species compendium: Salvinia molesta D.S. Mitchell

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Salvinia molesta D.S. Mitchell is an invasive aquatic fern native to a small area of south-eastern Brazil. It has spread throughout the world, forming thick mats of vegetation that decrease dissolved oxygen and pH while outcompeting native vegetation. It has been introduced and established into many...

  5. Historical Invasion Records Can Be Misleading: Genetic Evidence for Multiple Introductions of Invasive Raccoons (Procyon lotor) in Germany

    PubMed Central

    Fischer, Mari L.; Hochkirch, Axel; Heddergott, Mike; Schulze, Christoph; Anheyer-Behmenburg, Helena E.; Lang, Johannes; Michler, Frank-Uwe; Hohmann, Ulf; Ansorge, Hermann; Hoffmann, Lothar; Klein, Roland; Frantz, Alain C.

    2015-01-01

    Biological invasions provide excellent study systems to understand evolutionary, genetic and ecological processes during range expansions. There is strong evidence for positive effects of high propagule pressure and the associated higher genetic diversity on invasion success, but some species have become invasive despite small founder numbers. The raccoon (Procyon lotor) is often considered as a typical example for such a successful invasion resulting from a small number of founders. The species’ largest non-native population in Germany is commonly assumed to stem from a small number of founders and two separate founding events in the 1930s and 1940s. In the present study we analyzed 407 raccoons at 20 microsatellite loci sampled from the invasive range in Western Europe to test if these assumptions are correct. Contrary to the expectations, different genetic clustering methods detected evidence for at least four independent introduction events that gave rise to genetically differentiated subpopulations. Further smaller clusters were either artifacts or resulted from founder events at the range margin and recent release of captive individuals. We also found genetic evidence for on-going introductions of individuals. Furthermore a novel randomization process was used to determine the potential range of founder population size that would suffice to capture all the alleles present in a cluster. Our results falsify the assumption that this species has become widespread and abundant despite being genetically depauperate and show that historical records of species introductions may be misleading. PMID:25946257

  6. Historical Invasion Records Can Be Misleading: Genetic Evidence for Multiple Introductions of Invasive Raccoons (Procyon lotor) in Germany.

    PubMed

    Fischer, Mari L; Hochkirch, Axel; Heddergott, Mike; Schulze, Christoph; Anheyer-Behmenburg, Helena E; Lang, Johannes; Michler, Frank-Uwe; Hohmann, Ulf; Ansorge, Hermann; Hoffmann, Lothar; Klein, Roland; Frantz, Alain C

    2015-01-01

    Biological invasions provide excellent study systems to understand evolutionary, genetic and ecological processes during range expansions. There is strong evidence for positive effects of high propagule pressure and the associated higher genetic diversity on invasion success, but some species have become invasive despite small founder numbers. The raccoon (Procyon lotor) is often considered as a typical example for such a successful invasion resulting from a small number of founders. The species' largest non-native population in Germany is commonly assumed to stem from a small number of founders and two separate founding events in the 1930s and 1940s. In the present study we analyzed 407 raccoons at 20 microsatellite loci sampled from the invasive range in Western Europe to test if these assumptions are correct. Contrary to the expectations, different genetic clustering methods detected evidence for at least four independent introduction events that gave rise to genetically differentiated subpopulations. Further smaller clusters were either artifacts or resulted from founder events at the range margin and recent release of captive individuals. We also found genetic evidence for on-going introductions of individuals. Furthermore a novel randomization process was used to determine the potential range of founder population size that would suffice to capture all the alleles present in a cluster. Our results falsify the assumption that this species has become widespread and abundant despite being genetically depauperate and show that historical records of species introductions may be misleading.

  7. Trophic network architecture of root-associated bacterial communities determines pathogen invasion and plant health

    PubMed Central

    Wei, Zhong; Yang, Tianjie; Friman, Ville-Petri; Xu, Yangchun; Shen, Qirong; Jousset, Alexandre

    2015-01-01

    Host-associated bacterial communities can function as an important line of defence against pathogens in animals and plants. Empirical evidence and theoretical predictions suggest that species-rich communities are more resistant to pathogen invasions. Yet, the underlying mechanisms are unclear. Here, we experimentally test how the underlying resource competition networks of resident bacterial communities affect invasion resistance to the plant pathogen Ralstonia solanacearum in microcosms and in tomato plant rhizosphere. We find that bipartite resource competition networks are better predictors of invasion resistance compared with resident community diversity. Specifically, communities with a combination of stabilizing configurations (low nestedness and high connectance), and a clear niche overlap with the pathogen, reduce pathogen invasion success, constrain pathogen growth within invaded communities and have lower levels of diseased plants in greenhouse experiments. Bacterial resource competition network characteristics can thus be important in explaining positive diversity–invasion resistance relationships in bacterial rhizosphere communities. PMID:26400552

  8. Disturbance and diversity at two spatial scales.

    PubMed

    Limberger, Romana; Wickham, Stephen A

    2012-03-01

    The spatial scale of disturbance is a factor potentially influencing the relationship between disturbance and diversity. There has been discussion on whether disturbances that affect local communities and create a mosaic of patches in different successional stages have the same effect on diversity as regional disturbances that affect the whole landscape. In a microcosm experiment with metacommunities of aquatic protists, we compared the effect of local and regional disturbances on the disturbance-diversity relationship. Local disturbances destroyed entire local communities of the metacommunity and required reimmigration from neighboring communities, while regional disturbances affected the whole metacommunity but left part of each local community intact. Both disturbance types led to a negative relationship between disturbance intensity and Shannon diversity. With strong local disturbance, this decrease in diversity was due to species loss, while strong regional disturbance had no effect on species richness but reduced the evenness of the community. Growth rate appeared to be the most important trait for survival after strong local disturbance and dominance after strong regional disturbance. The pattern of the disturbance-diversity relationship was similar for both local and regional diversity. Although local disturbances at least temporally increased beta diversity by creating a mosaic of differently disturbed patches, this high dissimilarity did not result in regional diversity being increased relative to local diversity. The disturbance-diversity relationship was negative for both scales of diversity. The flat competitive hierarchy and absence of a trade-off between competition and colonization ability are a likely explanation for this pattern.

  9. The Chief Diversity Officer

    ERIC Educational Resources Information Center

    Williams, Damon; Wade-Golden, Katrina

    2007-01-01

    Numerous institutions are moving toward the chief diversity officer model of leading and managing diversity in higher education. These officers carry formal administrative titles and ranks that range from vice president for institutional diversity to associate vice chancellor for diversity and climate and dean of diversity and academic engagement.…

  10. Cheatgrass invasion and wildlife habitat

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The introduction and subsequent invasion of cheatgrass (Bromus tectorum) has altered native plant communities and the wildlife species that depend on these communities. Cheatgrass has truncated secondary succession by outcompeting native plant species for limited resources, thus building persistent...

  11. Nonpalpable invasive breast cancer.

    PubMed Central

    Wilhelm, M C; Edge, S B; Cole, D D; deParedes, E; Frierson, H F

    1991-01-01

    The use of mammography has resulted in 1464 breast biopsies for nonpalpable abnormalities at the University of Virginia in the 10 years 1980 to 1989. Two hundred sixty-four cancerous lesions (18%) were found. One hundred seventy-eight of these (67%) were in situ lesions. Invasive cancer (86 of 264 lesions or 33%) forms the basis for this report. Mammographic findings leading to biopsy were a mass in 61 of 86 cases (71%), microcalcifications in 23 of 86 (27%), or both in 2 of 86 cases. Histologic subtypes were infiltrating ductal (63 of 86), infiltrating lobular (14 of 86), and other infiltrating (9 of 86). Mastectomy was performed in 71 of 86 lesions (82%), lumpectomy/radiation in 14 of 86 (16%), and lumpectomy alone in 1 of 86 lesions. Division of the tumors into size with nodal status revealed 19 of 86 lesions (22%) less than 0.5 cm with 0 of 14 positive nodes. Thirty-nine of eighty-six lesions (46%) measured 0.6 to 1.0 cm with 10 (26%) positive nodes. Twenty-eight of eighty-six lesions (32%) measured more than 1.0 cm with 8 of 28 (28%) positive nodes. Nodal status is unknown for eight patients. Overall 18 of 78 lesions (23%) had positive nodes. Median follow-up is 44 months. Disease-free survival rate is 92% (79 of 86 patients) and overall survival rate is 94% (81 of 86 patients). Six of seven recurrences occurred in node-positive patients. For those with negative or unknown nodes, the disease-free survival rate is 98% (67 of 68 patients). These findings emphasize the benefit of early detection of breast cancer through the use of mammography. PMID:2039291

  12. Minimally Invasive Multivessel Coronary Surgery and Hybrid Coronary Revascularization: Can We Routinely Achieve Less Invasive Coronary Surgery?

    PubMed Central

    Rodriguez, Maria; Ruel, Marc

    2016-01-01

    Coronary artery bypass grafting (CABG) is the gold standard in managing severe coronary artery disease. However, it is associated with prolonged recovery and potential complications, in part due to the invasiveness of the procedure. Less invasive CABG techniques attempt to improve the quality and quantity of life in the same way as surgical revascularization but with fewer complications. Minimally invasive coronary surgery (MICS) through a small thoracotomy allows for complete revascularization with good results in graft patency. Perioperative mortality is low, and there is decreased need for blood transfusion, lower surgical site infection rates, and an earlier return to full physical function. Hybrid coronary revascularization (HCR) attempts to combine the advantages of coronary artery bypass grafting with those of percutaneous coronary intervention. Several studies have shown that HCR provides better short-term outcomes with regard to decreased ventilation and ICU time, reduced need for blood transfusion, and shortened hospital stay. However, the rates for major adverse cardiovascular events and mortality are comparable to conventional CABG, except for patients with a high SYNTAX score who displayed increased mortality rates. There is also strong evidence of a higher need for repeat revascularization with HCR compared to CABG. Overall, MICS and HCR appear to be viable alternatives to conventional CABG, offering a less invasive approach to coronary revascularization, which may be especially beneficial to high-risk patients. This article discusses approaches that deliver the advantages of minimally invasive surgical revascularization that can be adapted by surgeons with minimal investment with regards to training and infrastructure. PMID:27127557

  13. Global parasite and Rattus rodent invasions: The consequences for rodent-borne diseases.

    PubMed

    Morand, Serge; Bordes, Frédéric; Chen, Hsuan-Wien; Claude, Julien; Cosson, Jean-François; Galan, Maxime; Czirják, Gábor Á; Greenwood, Alex D; Latinne, Alice; Michaux, Johan; Ribas, Alexis

    2015-09-01

    We summarize the current knowledge on parasitism-related invasion processes of the globally invasive Rattus lineages, originating from Asia, and how these invasions have impacted the local epidemiology of rodent-borne diseases. Parasites play an important role in the invasion processes and successes of their hosts through multiple biological mechanisms such as "parasite release," "immunocompetence advantage," "biotic resistance" and "novel weapon." Parasites may also greatly increase the impact of invasions by spillover of parasites and other pathogens, introduced with invasive hosts, into new hosts, potentially leading to novel emerging diseases. Another potential impact is the ability of the invader to amplify local parasites by spillback. In both cases, local fauna and humans may be exposed to new health risks, which may decrease biodiversity and potentially cause increases in human morbidity and mortality. Here we review the current knowledge on these processes and propose some research priorities.

  14. The effect of urbanization on ant abundance and diversity: a temporal examination of factors affecting biodiversity.

    PubMed

    Buczkowski, Grzegorz; Richmond, Douglas S

    2012-01-01

    Numerous studies have examined the effect of urbanization on species richness and most studies implicate urbanization as the major cause of biodiversity loss. However, no study has identified an explicit connection between urbanization and biodiversity loss as the impact of urbanization is typically inferred indirectly by comparing species diversity along urban-rural gradients at a single time point. A different approach is to focus on the temporal rather than the spatial aspect and perform "before and after" studies where species diversity is cataloged over time in the same sites. The current study examined changes in ant abundance and diversity associated with the conversion of natural habitats into urban habitats. Ant abundance and diversity were tracked in forested sites that became urbanized through construction and were examined at 3 time points - before, during, and after construction. On average, 4.3 ± 1.2 unique species were detected in undisturbed plots prior to construction. Ant diversity decreased to 0.7 ± 0.8 species in plots undergoing construction and 1.5 ± 1.1 species in plots 1 year after construction was completed. With regard to species richness, urbanization resulted in the permanent loss of 17 of the 20 species initially present in the study plots. Recovery was slow and only 3 species were present right after construction was completed and 4 species were present 1 year after construction was completed. The second objective examined ant fauna recovery in developed residential lots based on time since construction, neighboring habitat quality, pesticide inputs, and the presence of invasive ants. Ant diversity was positively correlated with factors that promoted ecological recovery and negatively correlated with factors that promoted ecological degradation. Taken together, these results address a critical gap in our knowledge by characterizing the short- and long-term the effects of urbanization on the loss of ant biodiversity.

  15. The Effect of Urbanization on Ant Abundance and Diversity: A Temporal Examination of Factors Affecting Biodiversity

    PubMed Central

    Buczkowski, Grzegorz; Richmond, Douglas S.

    2012-01-01

    Numerous studies have examined the effect of urbanization on species richness and most studies implicate urbanization as the major cause of biodiversity loss. However, no study has identified an explicit connection between urbanization and biodiversity loss as the impact of urbanization is typically inferred indirectly by comparing species diversity along urban-rural gradients at a single time point. A different approach is to focus on the temporal rather than the spatial aspect and perform “before and after” studies where species diversity is cataloged over time in the same sites. The current study examined changes in ant abundance and diversity associated with the conversion of natural habitats into urban habitats. Ant abundance and diversity were tracked in forested sites that became urbanized through construction and were examined at 3 time points - before, during, and after construction. On average, 4.3±1.2 unique species were detected in undisturbed plots prior to construction. Ant diversity decreased to 0.7±0.8 species in plots undergoing construction and 1.5±1.1 species in plots 1 year after construction was completed. With regard to species richness, urbanization resulted in the permanent loss of 17 of the 20 species initially present in the study plots. Recovery was slow and only 3 species were present right after construction was completed and 4 species were present 1 year after construction was completed. The second objective examined ant fauna recovery in developed residential lots based on time since construction, neighboring habitat quality, pesticide inputs, and the presence of invasive ants. Ant diversity was positively correlated with factors that promoted ecological recovery and negatively correlated with factors that promoted ecological degradation. Taken together, these results address a critical gap in our knowledge by characterizing the short- and long-term the effects of urbanization on the loss of ant biodiversity. PMID:22876291

  16. Calbindins decreased after space flight

    NASA Technical Reports Server (NTRS)

    Sergeev, I. N.; Rhoten, W. B.; Carney, M. D.

    1996-01-01

    Exposure of the body to microgravity during space flight causes a series of well-documented changes in Ca2+ metabolism, yet the cellular and molecular mechanisms leading to these changes are poorly understood. Calbindins, vitamin D-dependent Ca2+ binding proteins, are believed to have a significant role in maintaining cellular Ca2+ homeostasis. In this study, we used biochemical and immunocytochemical approaches to analyze the expression of calbindin-D28k and calbindin-D9k in kidneys, small intestine, and pancreas of rats flown for 9 d aboard the space shuttle. The effects of microgravity on calbindins in rats from space were compared with synchronous Animal Enclosure Module controls, modeled weightlessness animals (tail suspension), and their controls. Exposure to microgravity resulted in a significant and sustained decrease in calbindin-D28k content in the kidney and calbindin-D9k in the small intestine of flight animals, as measured by enzyme-linked immunosorbent assay (ELISA). Modeled weightlessness animals exhibited a similar decrease in calbindins by ELISA. Immunocytochemistry (ICC) in combination with quantitative computer image analysis was used to measure in situ the expression of calbindins in the kidney and the small intestine, and the expression of insulin in pancreas. There was a large decrease of immunoreactivity in renal distal tubular cell-associated calbindin-D28k and in intestinal absorptive cell-associated calbindin-D9k of space flight and modeled weightlessness animals compared with matched controls. No consistent difference in pancreatic insulin immunoreactivity between space flight, modeled weightlessness, and controls was observed. Regression analysis of results obtained by quantitative ICC and ELISA for space flight, modeled weightlessness animals, and their controls demonstrated a significant correlation. These findings after a short-term exposure to microgravity or modeled weightlessness suggest that a decreased expression of calbindins

  17. Propagule pressure-invasibility relationships: testing the influence of soil fertility and disturbance with Lespedeza cuneata.

    PubMed

    Houseman, Gregory R; Foster, Bryan L; Brassil, Chad E

    2014-02-01

    Although invasion risk is expected to increase with propagule pressure (PP), it is unclear whether PP-invasibility relationships follow an asymptotic or some other non-linear form and whether such relationships vary with underlying environmental conditions. Using manipulations of PP, soil fertility and disturbance, we tested how each influence PP-invasibility relationships for Lespedeza cuneata in a Kansas grassland and use recruitment curve models to determine how safe sites may contribute to plant invasions. After three growing seasons, we found that the PP-invasibility relationships best fit an asymptotic model of invasion reflecting a combination of density-independent and density-dependent processes and that seeds were aggregated within the plant community despite efforts to uniformly sow seeds. Consistent with some models, community invasibility decreased with enhanced soil fertility or reduced levels of disturbance in response to changes in the fraction of safe sites. Our results illustrate that disturbance and soil fertility can be a useful organizing principle for predicting community invasibility, asymptotic models are a reasonable starting point for modeling invasion, and new modeling techniques—coupled with classic experimental approaches—can enhance our understanding of the invasion process.

  18. Management of urolithiasis in patients after urinary diversions.

    PubMed

    Okhunov, Zhamshid; Duty, Brian; Smith, Arthur D; Okeke, Zeph

    2011-08-01

    After urinary diversion patients are at increased risk of long-term complications, including stones of the upper urinary tract and reservoir or conduit. Advances in instrumentation and techniques have expanded treatment options, while minimizing morbidity. Minimally invasive treatment methods include shockwave lithotripsy, antegrade and retrograde ureteroscopic lithotripsy and percutaneous nephrolithotomy. Percutaneous and laparoscopic techniques are applicable to stones within urinary diversions. Medical management is crucial for avoiding recurrent stones in these patients.

  19. Minimally Invasive Spinal Surgery with Intraoperative Image-Guided Navigation.

    PubMed

    Kim, Terrence T; Johnson, J Patrick; Pashman, Robert; Drazin, Doniel

    2016-01-01

    We present our perioperative minimally invasive spine surgery technique using intraoperative computed tomography image-guided navigation for the treatment of various lumbar spine pathologies. We present an illustrative case of a patient undergoing minimally invasive percutaneous posterior spinal fusion assisted by the O-arm system with navigation. We discuss the literature and the advantages of the technique over fluoroscopic imaging methods: lower occupational radiation exposure for operative room personnel, reduced need for postoperative imaging, and decreased revision rates. Most importantly, we demonstrate that use of intraoperative cone beam CT image-guided navigation has been reported to increase accuracy. PMID:27213152

  20. Minimally Invasive Spinal Surgery with Intraoperative Image-Guided Navigation

    PubMed Central

    Kim, Terrence T.; Johnson, J. Patrick; Pashman, Robert; Drazin, Doniel

    2016-01-01

    We present our perioperative minimally invasive spine surgery technique using intraoperative computed tomography image-guided navigation for the treatment of various lumbar spine pathologies. We present an illustrative case of a patient undergoing minimally invasive percutaneous posterior spinal fusion assisted by the O-arm system with navigation. We discuss the literature and the advantages of the technique over fluoroscopic imaging methods: lower occupational radiation exposure for operative room personnel, reduced need for postoperative imaging, and decreased revision rates. Most importantly, we demonstrate that use of intraoperative cone beam CT image-guided navigation has been reported to increase accuracy. PMID:27213152

  1. Monoamine oxidase A (MAO A) inhibitors decrease glioma progression.

    PubMed

    Kushal, Swati; Wang, Weijun; Vaikari, Vijaya Pooja; Kota, Rajesh; Chen, Kevin; Yeh, Tzu-Shao; Jhaveri, Niyati; Groshen, Susan L; Olenyuk, Bogdan Z; Chen, Thomas C; Hofman, Florence M; Shih, Jean C

    2016-03-22

    Glioblastoma (GBM) is an aggressive brain tumor which is currently treated with temozolomide (TMZ). Tumors usually become resistant to TMZ and recur; no effective therapy is then available. Monoamine Oxidase A (MAO A) oxidizes monoamine neurotransmitters resulting in reactive oxygen species which cause cancer. This study shows that MAO A expression is increased in human glioma tissues and cell lines. MAO A inhibitors, clorgyline or the near-infrared-dye MHI-148 conjugated to clorgyline (NMI), were cytotoxic for glioma and decreased invasion in vitro. Using the intracranial TMZ-resistant glioma model, clorgyline or NMI alone or in combination with low-dose TMZ reduced tumor growth and increased animal survival. NMI was localized specifically to the tumor. Immunocytochemistry studies showed that the MAO A inhibitor reduced proliferation, microvessel density and invasion, and increased macrophage infiltration. In conclusion, we have identified MAO A inhibitors as potential novel stand-alone drugs or as combination therapy with low dose TMZ for drug-resistant gliomas. NMI can also be used as a non-invasive imaging tool. Thus has a dual function for both therapy and diagnosis.

  2. Decreasing Fires in Mediterranean Europe.

    PubMed

    Turco, Marco; Bedia, Joaquín; Di Liberto, Fabrizio; Fiorucci, Paolo; von Hardenberg, Jost; Koutsias, Nikos; Llasat, Maria-Carmen; Xystrakis, Fotios; Provenzale, Antonello

    2016-01-01

    Forest fires are a serious environmental hazard in southern Europe. Quantitative assessment of recent trends in fire statistics is important for assessing the possible shifts induced by climate and other environmental/socioeconomic changes in this area. Here we analyse recent fire trends in Portugal, Spain, southern France, Italy and Greece, building on a homogenized fire database integrating official fire statistics provided by several national/EU agencies. During the period 1985-2011, the total annual burned area (BA) displayed a general decreasing trend, with the exception of Portugal, where a heterogeneous signal was found. Considering all countries globally, we found that BA decreased by about 3020 km2 over the 27-year-long study period (i.e. about -66% of the mean historical value). These results are consistent with those obtained on longer time scales when data were available, also yielding predominantly negative trends in Spain and France (1974-2011) and a mixed trend in Portugal (1980-2011). Similar overall results were found for the annual number of fires (NF), which globally decreased by about 12600 in the study period (about -59%), except for Spain where, excluding the provinces along the Mediterranean coast, an upward trend was found for the longer period. We argue that the negative trends can be explained, at least in part, by an increased effort in fire management and prevention after the big fires of the 1980's, while positive trends may be related to recent socioeconomic transformations leading to more hazardous landscape configurations, as well as to the observed warming of recent decades. We stress the importance of fire data homogenization prior to analysis, in order to alleviate spurious effects associated with non-stationarities in the data due to temporal variations in fire detection efforts. PMID:26982584

  3. Decreasing Fires in Mediterranean Europe.

    PubMed

    Turco, Marco; Bedia, Joaquín; Di Liberto, Fabrizio; Fiorucci, Paolo; von Hardenberg, Jost; Koutsias, Nikos; Llasat, Maria-Carmen; Xystrakis, Fotios; Provenzale, Antonello

    2016-01-01

    Forest fires are a serious environmental hazard in southern Europe. Quantitative assessment of recent trends in fire statistics is important for assessing the possible shifts induced by climate and other environmental/socioeconomic changes in this area. Here we analyse recent fire trends in Portugal, Spain, southern France, Italy and Greece, building on a homogenized fire database integrating official fire statistics provided by several national/EU agencies. During the period 1985-2011, the total annual burned area (BA) displayed a general decreasing trend, with the exception of Portugal, where a heterogeneous signal was found. Considering all countries globally, we found that BA decreased by about 3020 km2 over the 27-year-long study period (i.e. about -66% of the mean historical value). These results are consistent with those obtained on longer time scales when data were available, also yielding predominantly negative trends in Spain and France (1974-2011) and a mixed trend in Portugal (1980-2011). Similar overall results were found for the annual number of fires (NF), which globally decreased by about 12600 in the study period (about -59%), except for Spain where, excluding the provinces along the Mediterranean coast, an upward trend was found for the longer period. We argue that the negative trends can be explained, at least in part, by an increased effort in fire management and prevention after the big fires of the 1980's, while positive trends may be related to recent socioeconomic transformations leading to more hazardous landscape configurations, as well as to the observed warming of recent decades. We stress the importance of fire data homogenization prior to analysis, in order to alleviate spurious effects associated with non-stationarities in the data due to temporal variations in fire detection efforts.

  4. Decreasing Fires in Mediterranean Europe

    PubMed Central

    Turco, Marco; Bedia, Joaquín; Di Liberto, Fabrizio; Fiorucci, Paolo; von Hardenberg, Jost; Koutsias, Nikos; Llasat, Maria-Carmen; Xystrakis, Fotios; Provenzale, Antonello

    2016-01-01

    Forest fires are a serious environmental hazard in southern Europe. Quantitative assessment of recent trends in fire statistics is important for assessing the possible shifts induced by climate and other environmental/socioeconomic changes in this area. Here we analyse recent fire trends in Portugal, Spain, southern France, Italy and Greece, building on a homogenized fire database integrating official fire statistics provided by several national/EU agencies. During the period 1985-2011, the total annual burned area (BA) displayed a general decreasing trend, with the exception of Portugal, where a heterogeneous signal was found. Considering all countries globally, we found that BA decreased by about 3020 km2 over the 27-year-long study period (i.e. about -66% of the mean historical value). These results are consistent with those obtained on longer time scales when data were available, also yielding predominantly negative trends in Spain and France (1974-2011) and a mixed trend in Portugal (1980-2011). Similar overall results were found for the annual number of fires (NF), which globally decreased by about 12600 in the study period (about -59%), except for Spain where, excluding the provinces along the Mediterranean coast, an upward trend was found for the longer period. We argue that the negative trends can be explained, at least in part, by an increased effort in fire management and prevention after the big fires of the 1980’s, while positive trends may be related to recent socioeconomic transformations leading to more hazardous landscape configurations, as well as to the observed warming of recent decades. We stress the importance of fire data homogenization prior to analysis, in order to alleviate spurious effects associated with non-stationarities in the data due to temporal variations in fire detection efforts. PMID:26982584

  5. SOST Inhibits Prostate Cancer Invasion

    PubMed Central

    Hudson, Bryan D.; Hum, Nicholas R.; Thomas, Cynthia B.; Kohlgruber, Ayano; Sebastian, Aimy; Collette, Nicole M.; Coleman, Matthew A.; Christiansen, Blaine A.; Loots, Gabriela G.

    2015-01-01

    Inhibitors of Wnt signaling have been shown to be involved in prostate cancer (PC) metastasis; however the role of Sclerostin (Sost) has not yet been explored. Here we show that elevated Wnt signaling derived from Sost deficient osteoblasts promotes PC invasion, while rhSOST has an inhibitory effect. In contrast, rhDKK1 promotes PC elongation and filopodia formation, morphological changes characteristic of an invasive phenotype. Furthermore, rhDKK1 was found to activate canonical Wnt signaling in PC3 cells, suggesting that SOST and DKK1 have opposing roles on Wnt signaling in this context. Gene expression analysis of PC3 cells co-cultured with OBs exhibiting varying amounts of Wnt signaling identified CRIM1 as one of the transcripts upregulated under highly invasive conditions. We found CRIM1 overexpression to also promote cell-invasion. These findings suggest that bone-derived Wnt signaling may enhance PC tropism by promoting CRIM1 expression and facilitating cancer cell invasion and adhesion to bone. We concluded that SOST and DKK1 have opposing effects on PC3 cell invasion and that bone-derived Wnt signaling positively contributes to the invasive phenotypes of PC3 cells by activating CRIM1 expression and facilitating PC-OB physical interaction. As such, we investigated the effects of high concentrations of SOST in vivo. We found that PC3-cells overexpressing SOST injected via the tail vein in NSG mice did not readily metastasize, and those injected intrafemorally had significantly reduced osteolysis, suggesting that targeting the molecular bone environment may influence bone metastatic prognosis in clinical settings. PMID:26545120

  6. SOST Inhibits Prostate Cancer Invasion.

    PubMed

    Hudson, Bryan D; Hum, Nicholas R; Thomas, Cynthia B; Kohlgruber, Ayano; Sebastian, Aimy; Collette, Nicole M; Coleman, Matthew A; Christiansen, Blaine A; Loots, Gabriela G

    2015-01-01

    Inhibitors of Wnt signaling have been shown to be involved in prostate cancer (PC) metastasis; however the role of Sclerostin (Sost) has not yet been explored. Here we show that elevated Wnt signaling derived from Sost deficient osteoblasts promotes PC invasion, while rhSOST has an inhibitory effect. In contrast, rhDKK1 promotes PC elongation and filopodia formation, morphological changes characteristic of an invasive phenotype. Furthermore, rhDKK1 was found to activate canonical Wnt signaling in PC3 cells, suggesting that SOST and DKK1 have opposing roles on Wnt signaling in this context. Gene expression analysis of PC3 cells co-cultured with OBs exhibiting varying amounts of Wnt signaling identified CRIM1 as one of the transcripts upregulated under highly invasive conditions. We found CRIM1 overexpression to also promote cell-invasion. These findings suggest that bone-derived Wnt signaling may enhance PC tropism by promoting CRIM1 expression and facilitating cancer cell invasion and adhesion to bone. We concluded that SOST and DKK1 have opposing effects on PC3 cell invasion and that bone-derived Wnt signaling positively contributes to the invasive phenotypes of PC3 cells by activating CRIM1 expression and facilitating PC-OB physical interaction. As such, we investigated the effects of high concentrations of SOST in vivo. We found that PC3-cells overexpressing SOST injected via the tail vein in NSG mice did not readily metastasize, and those injected intrafemorally had significantly reduced osteolysis, suggesting that targeting the molecular bone environment may influence bone metastatic prognosis in clinical settings.

  7. Does high biodiversity reduce the risk of Lyme disease invasion?

    PubMed Central

    2013-01-01

    Background It has been suggested that increasing biodiversity, specifically host diversity, reduces pathogen and parasite transmission amongst wildlife (causing a “dilution effect”), whereby transmission amongst efficient reservoir hosts, (e.g. Peromyscus spp. mice for the agent of Lyme disease Borrelia burgdorferi) is reduced by the presence of other less efficient host species. If so, then increasing biodiversity should inhibit pathogen and parasite invasion. Methods We investigated this hypothesis by studying invasion of B. burgdorferi and its tick vector Ixodes scapularis in 71 field sites in southeastern Canada. Indices of trapped rodent host diversity, and of biodiversity of the wider community, were investigated as variables explaining the numbers of I. scapularis collected and B. burgdorferi infection in these ticks. A wide range of alternative environmental explanatory variables were also considered. Results The observation of low I. scapularis abundance and low B. burgdorferi infection prevalence in sites where I. scapularis were detected was consistent with early-stage invasion of the vector. There were significant associations between the abundance of ticks and season, year of study and ambient temperature. Abundance of host-seeking larvae was significantly associated with deer density, and abundance of host-seeking larvae and nymphs were positively associated with litter layer depth. Larval host infestations were lower where the relative proportion of non-Peromyscus spp. was high. Infestations of hosts with nymphs were lower when host species richness was higher, but overall nymphal abundance increased with species richness because Peromyscus spp. mouse abundance and host species richness were positively correlated. Nymphal infestations of hosts were lower where tree species richness was higher. B. burgdorferi infection prevalence in ticks varied significantly with an index of rates of migratory bird-borne vector and pathogen invasion. Conclusions

  8. Impacts of invasive nonnative plant species on the rare forest herb Scutellaria montana

    NASA Astrophysics Data System (ADS)

    Sikkema, Jordan J.; Boyd, Jennifer N.

    2015-11-01

    Invasive plant species and overabundant herbivore populations have the potential to significantly impact rare plant species given their increased risk for local extirpation and extinction. We used interacting invasive species removal and grazer exclusion treatments replicated across two locations in an occurrence of rare Scutellaria montana (large-flowered skullcap) in Chattanooga, Tennessee, USA, to assess: 1) competition by invasive Ligustrum sinense (Chinese privet) and Lonicera japonica (Japanese honeysuckle) and 2) the role of invasive species in mediating Oedocoilus virginianus (white-tailed deer) grazing of S. montana. Contrary to our hypothesis that invasive species presence would suppress S. montana directly via competition, S. montana individuals experienced a seasonal increase in stem height when invasive species were intact but not when invasive species were removed. Marginally significant results indicated that invasive species may afford S. montana protection from grazers, and we suggest that invasive species also could protect S. montana from smaller herbivores and/or positively influence abiotic conditions. In contrast to growth responses, S. montana individuals protected from O. virginianus exhibited a decrease in flowering between seasons relative to unprotected plants, but invasive species did not affect this variable. Although it has been suggested that invasive plant species may negatively influence S. montana growth and fecundity, our findings do not support related concerns. As such, we suggest that invasive species eradication efforts in S. montana habitat could be more detrimental than positive due to associated disturbance. However, the low level of invasion of our study site may not be representative of potential interference in more heavily infested habitat.

  9. Phylogeographic insights into the invasion history and secondary spread of the signal crayfish in Japan.

    PubMed

    Usio, Nisikawa; Azuma, Noriko; Larson, Eric R; Abbott, Cathryn L; Olden, Julian D; Akanuma, Hiromi; Takamura, Kenzi; Takamura, Noriko

    2016-08-01

    Successful invasion by nonindigenous species is often attributed to high propagule pressure, yet some foreign species become widespread despite showing reduced genetic variation due to founder effects. The signal crayfish (Pacifastacus leniusculus) is one such example, where rapid spread across Japan in recent decades is believed to be the result of only three founding populations. To infer the history and explore the success of this remarkable crayfish invasion, we combined detailed phylogeographical and morphological analyses conducted in both the introduced and native ranges. We sequenced 16S mitochondrial DNA of signal crayfish from across the introduced range in Japan (537 samples, 20 sites) and the native range in western North America (700 samples, 50 sites). Because chela size is often related to aggressive behavior in crayfish, and hence, their invasion success, we also measured chela size of a subset of specimens in both introduced and native ranges. Genetic diversity of introduced signal crayfish populations was as high as that of the dominant phylogeographic group in the native range, suggesting high propagule pressure during invasion. More recently established crayfish populations in Japan that originated through secondary spread from one of the founding populations exhibit reduced genetic diversity relative to older populations, probably as a result of founder effects. However, these newer populations also show larger chela size, consistent with expectations of rapid adaptations or phenotypic responses during the invasion process. Introduced signal crayfish populations in Japan originate from multiple source populations from a wide geographic range in the native range of western North America. A combination of high genetic diversity, especially for older populations in the invasive range, and rapid adaptation to colonization, manifested as larger chela in rec