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Sample records for strict host specificity

  1. Strict Host-Symbiont Cospeciation and Reductive Genome Evolution in Insect Gut Bacteria

    Science.gov (United States)

    Hosokawa, Takahiro; Kikuchi, Yoshitomo; Nikoh, Naruo; Shimada, Masakazu; Fukatsu, Takema

    2006-01-01

    Host-symbiont cospeciation and reductive genome evolution have been identified in obligate endocellular insect symbionts, but no such example has been identified from extracellular ones. Here we first report such a case in stinkbugs of the family Plataspidae, wherein a specific gut bacterium is vertically transmitted via “symbiont capsule.” In all of the plataspid species, females produced symbiont capsules upon oviposition and their gut exhibited specialized traits for capsule production. Phylogenetic analysis showed that the plataspid symbionts constituted a distinct group in the γ-Proteobacteria, whose sister group was the aphid obligate endocellular symbionts Buchnera. Removal of the symbionts resulted in retarded growth, mortality, and sterility of the insects. The host phylogeny perfectly agreed with the symbiont phylogeny, indicating strict host-symbiont cospeciation despite the extracellular association. The symbionts exhibited AT-biased nucleotide composition, accelerated molecular evolution, and reduced genome size, as has been observed in obligate endocellular insect symbionts. These findings suggest that not the endocellular conditions themselves but the population genetic attributes of the vertically transmitted symbionts are probably responsible for the peculiar genetic traits of these insect symbionts. We proposed the designation “Candidatus Ishikawaella capsulata” for the plataspid symbionts. The plataspid stinkbugs, wherein the host-symbiont associations can be easily manipulated, provide a novel system that enables experimental approaches to previously untouched aspects of the insect-microbe mutualism. Furthermore, comparative analyses of the sister groups, the endocellular Buchnera and the extracellular Ishikawaella, would lead to insights into how the different symbiotic lifestyles have affected their genomic evolution. PMID:17032065

  2. Sponge-associated bacteria are strictly maintained in two closely related but geographically distant sponge hosts.

    Science.gov (United States)

    Montalvo, Naomi F; Hill, Russell T

    2011-10-01

    The giant barrel sponges Xestospongia muta and Xestospongia testudinaria are ubiquitous in tropical reefs of the Atlantic and Pacific Oceans, respectively. They are key species in their respective environments and are hosts to diverse assemblages of bacteria. These two closely related sponges from different oceans provide a unique opportunity to examine the evolution of sponge-associated bacterial communities. Mitochondrial cytochrome oxidase subunit I gene sequences from X. muta and X. testudinaria showed little divergence between the two species. A detailed analysis of the bacterial communities associated with these sponges, comprising over 900 full-length 16S rRNA gene sequences, revealed remarkable similarity in the bacterial communities of the two species. Both sponge-associated communities include sequences found only in the two Xestospongia species, as well as sequences found also in other sponge species and are dominated by three bacterial groups, Chloroflexi, Acidobacteria, and Actinobacteria. While these groups consistently dominate the bacterial communities revealed by 16S rRNA gene-based analysis of sponge-associated bacteria, the depth of sequencing undertaken in this study revealed clades of bacteria specifically associated with each of the two Xestospongia species, and also with the genus Xestospongia, that have not been found associated with other sponge species or other ecosystems. This study, comparing the bacterial communities associated with closely related but geographically distant sponge hosts, gives new insight into the intimate relationships between marine sponges and some of their bacterial symbionts.

  3. Host specificity in bat ectoparasites: a natural experiment.

    Science.gov (United States)

    Seneviratne, Sampath S; Fernando, H Chandrika; Udagama-Randeniya, Preethi V

    2009-07-15

    We undertook a field study to determine patterns of specialisation of ectoparasites in cave-dwelling bats in Sri Lanka. The hypothesis tested was that strict host specificity (monoxeny) could evolve through the development of differential species preferences through association with the different host groups. Three species of cave-dwelling bats were chosen to represent a wide range of host-parasite associations (monoxeny to polyxeny), and both sympatric and allopatric roosting assemblages. Of the eight caves selected, six caves were "allopatric" roosts where two of each housed only one of the three host species examined: Rousettus leschenaulti (Pteropodidae), Rhinolophus rouxi and Hipposideros speoris (Rhinolophidae). The remaining two caves were "sympatric" roosts and housed all three host species. Thirty bats of each species were examined for ectoparasites in each cave, which resulted in a collection of nycteribiid and streblid flies, an ischnopsyllid bat flea, argasid and ixodid ticks, and mites belonging to three families. The host specificity of bat parasites showed a trend to monoxeny in which 70% of the 30 species reported were monoxenous. Odds ratios derived from chi(2)-tests revealed two levels of host preferences in less-specific parasites (i) the parasite was found on two host species under conditions of both host sympatry and host allopatry, with a preference for a single host in the case of host sympatry and (ii) the preference for a single host was very high, hence under conditions of host sympatry, it was confined to the preferred host only. However, under conditions of host allopatry, it utilized both hosts. There appears to be an increasing prevalence in host preferences of the parasites toward confinement to a single host species. The ecological isolation of the bat hosts and a long history of host-parasite co-existence could have contributed to an overall tendency of bat ectoparasites to become specialists, here reflected in the high percentage

  4. Sponge-Associated Bacteria Are Strictly Maintained in Two Closely Related but Geographically Distant Sponge Hosts ▿ † ‡ §

    Science.gov (United States)

    Montalvo, Naomi F.; Hill, Russell T.

    2011-01-01

    The giant barrel sponges Xestospongia muta and Xestospongia testudinaria are ubiquitous in tropical reefs of the Atlantic and Pacific Oceans, respectively. They are key species in their respective environments and are hosts to diverse assemblages of bacteria. These two closely related sponges from different oceans provide a unique opportunity to examine the evolution of sponge-associated bacterial communities. Mitochondrial cytochrome oxidase subunit I gene sequences from X. muta and X. testudinaria showed little divergence between the two species. A detailed analysis of the bacterial communities associated with these sponges, comprising over 900 full-length 16S rRNA gene sequences, revealed remarkable similarity in the bacterial communities of the two species. Both sponge-associated communities include sequences found only in the two Xestospongia species, as well as sequences found also in other sponge species and are dominated by three bacterial groups, Chloroflexi, Acidobacteria, and Actinobacteria. While these groups consistently dominate the bacterial communities revealed by 16S rRNA gene-based analysis of sponge-associated bacteria, the depth of sequencing undertaken in this study revealed clades of bacteria specifically associated with each of the two Xestospongia species, and also with the genus Xestospongia, that have not been found associated with other sponge species or other ecosystems. This study, comparing the bacterial communities associated with closely related but geographically distant sponge hosts, gives new insight into the intimate relationships between marine sponges and some of their bacterial symbionts. PMID:21856832

  5. Pseudouridine synthase 1: a site-specific synthase without strict sequence recognition requirements

    Science.gov (United States)

    Sibert, Bryan S.; Patton, Jeffrey R.

    2012-01-01

    Pseudouridine synthase 1 (Pus1p) is an unusual site-specific modification enzyme in that it can modify a number of positions in tRNAs and can recognize several other types of RNA. No consensus recognition sequence or structure has been identified for Pus1p. Human Pus1p was used to determine which structural or sequence elements of human tRNASer are necessary for pseudouridine (Ψ) formation at position 28 in the anticodon stem-loop (ASL). Some point mutations in the ASL stem of tRNASer had significant effects on the levels of modification and compensatory mutation, to reform the base pair, restored a wild-type level of Ψ formation. Deletion analysis showed that the tRNASer TΨC stem-loop was a determinant for modification in the ASL. A mini-substrate composed of the ASL and TΨC stem-loop exhibited significant Ψ formation at position 28 and a number of mutants were tested. Substantial base pairing in the ASL stem (3 out of 5 bp) is required, but the sequence of the TΨC loop is not required for modification. When all nucleotides in the ASL stem other than U28 were changed in a single mutant, but base pairing was retained, a near wild-type level of modification was observed. PMID:22102571

  6. Sponge-Associated Bacteria Are Strictly Maintained in Two Closely Related but Geographically Distant Sponge Hosts ▿ † ‡ §

    OpenAIRE

    Montalvo, Naomi F.; Hill, Russell T.

    2011-01-01

    The giant barrel sponges Xestospongia muta and Xestospongia testudinaria are ubiquitous in tropical reefs of the Atlantic and Pacific Oceans, respectively. They are key species in their respective environments and are hosts to diverse assemblages of bacteria. These two closely related sponges from different oceans provide a unique opportunity to examine the evolution of sponge-associated bacterial communities. Mitochondrial cytochrome oxidase subunit I gene sequences from X. muta and X. testu...

  7. Host Range Specificity in Verticillium dahliae.

    Science.gov (United States)

    Bhat, R G; Subbarao, K V

    1999-12-01

    ABSTRACT Verticillium dahliae isolates from artichoke, bell pepper, cabbage, cauliflower, chili pepper, cotton, eggplant, lettuce, mint, potato, strawberry, tomato, and watermelon and V. albo-atrum from alfalfa were evaluated for their pathogenicity on all 14 hosts. One-month-old seedlings were inoculated with a spore suspension of about 10(7) conidia per ml using a root-dip technique and incubated in the greenhouse. Disease incidence and severity, plant height, and root and shoot dry weights were recorded 6 weeks after inoculation. Bell pepper, cabbage, cauliflower, cotton, eggplant, and mint isolates exhibited host specificity and differential pathogenicity on other hosts, whereas isolates from artichoke, lettuce, potato, strawberry, tomato, and watermelon did not. Bell pepper was resistant to all Verticillium isolates except isolates from bell pepper and eggplant. Thus, host specificity exists in some isolates of V. dahliae. The same isolates were characterized for vegetative compatibility groups (VCGs) through complementation of nitrate nonutilizing (nit) mutants. Cabbage and cauliflower isolates did not produce nit mutants. The isolate from cotton belonged to VCG 1; isolates from bell pepper, eggplant, potato, and tomato, to VCG 4; and the remaining isolates, to VCG 2. These isolates were also analyzed using the random amplified polymorphic DNA (RAPD) method. Forty random primers were screened, and eighteen of them amplified DNA from Verticillium. Based on RAPD banding patterns, cabbage and cauliflower isolates formed a unique group, distinct from other V. dahliae and V. albo-atrum groups. Minor genetic variations were observed among V. dahliae isolates from other hosts, regardless of whether they were host specific or not. There was no correlation among pathogenicity, VCGs, and RAPD banding patterns. Even though the isolates belonged to different VCGs, they shared similar RAPD profiles. These results suggest that management of Verticillium wilt in some crops

  8. Molecular mechanism of strict substrate specificity of an extradiol dioxygenase, DesB, derived from Sphingobium sp. SYK-6.

    Directory of Open Access Journals (Sweden)

    Keisuke Sugimoto

    Full Text Available DesB, which is derived from Sphingobium sp. SYK-6, is a type II extradiol dioxygenase that catalyzes a ring opening reaction of gallate. While typical extradiol dioxygenases show broad substrate specificity, DesB has strict substrate specificity for gallate. The substrate specificity of DesB seems to be required for the efficient growth of S. sp. SYK-6 using lignin-derived aromatic compounds. Since direct coordination of hydroxyl groups of the substrate to the non-heme iron in the active site is a critical step for the catalytic reaction of the extradiol dioxygenases, the mechanism of the substrate recognition and coordination of DesB was analyzed by biochemical and crystallographic methods. Our study demonstrated that the direct coordination between the non-heme iron and hydroxyl groups of the substrate requires a large shift of the Fe (II ion in the active site. Mutational analysis revealed that His124 and His192 in the active site are essential to the catalytic reaction of DesB. His124, which interacts with OH (4 of the bound gallate, seems to contribute to proper positioning of the substrate in the active site. His192, which is located close to OH (3 of the gallate, is likely to serve as the catalytic base. Glu377' interacts with OH (5 of the gallate and seems to play a critical role in the substrate specificity. Our biochemical and structural study showed the substrate recognition and catalytic mechanisms of DesB.

  9. Predictors of Host Specificity among Behavior-Manipulating Parasites

    DEFF Research Database (Denmark)

    Fredensborg, B. L.

    2014-01-01

    specifically, hosts’ behavioral modification that involves interaction with the central nervous system presumably restricts parasites to more closely related hosts than does manipulation of the host’s behavior via debilitation of the host’s physiology. The results of the analysis suggest that phylogenetic......-specialist that has a restricted ecological niche that it masters. Parasites that manipulate hosts’ behavior are often thought to represent resource-specialists based on a few spectacular examples of manipulation of the host’s behavior. However, the determinants of which, and how many, hosts a manipulating parasite...... of parasites and hosts. Using individual and multivariate analyses, I examined the effect of the host’s and parasite’s taxonomy, location of the parasite in the host, type of behavioral change, and the effect of debilitation on host-specificity, measured as the mean taxonomic relatedness of hosts...

  10. Specific developmental pathways underlie host specificity in the parasitic plant Orobanche

    Science.gov (United States)

    Hiscock, Simon

    2010-01-01

    Parasitic angiosperms are an ecologically and economically important group of plants. However our understanding of the basis for host specificity in these plants is embryonic. Recently we investigated host specificity in the parasitic angiosperm Orobanche minor, and demonstrated that this host generalist parasite comprises genetically defined races that are physiologically adapted to specific hosts. Populations occurring naturally on red clover (Trifolium pratense) and sea carrot (Daucus carota subsp. gummifer) respectively, showed distinct patterns of host specificity at various developmental stages, and a higher fitness on their natural hosts, suggesting these races are locally adapted. Here we discuss the implications of our findings from a broader perspective. We suggest that differences in signal responsiveness and perception by the parasite, as well as qualitative differences in signal production by the host, may elicit host specificity in this parasitic plant. Together with our earlier demonstration that these O. minor races are genetically distinct based on molecular markers, our recent data provide a snapshot of speciation in action, driven by host specificity. Indeed, host specificity may be an underestimated catalyst for speciation in parasitic plants generally. We propose that identifying host specific races using physiological techniques will complement conventional molecular marker-based approaches to provide a framework for delineating evolutionary relationships among cryptic host-specific parasitic plants. PMID:20081361

  11. Host-specific functional significance of Caenorhabditis gut commensals

    Directory of Open Access Journals (Sweden)

    Maureen Berg

    2016-10-01

    Full Text Available The gut microbiota is an important contributor to host health and fitness. Given its importance, microbiota composition should not be left to chance. However, what determines this composition is far from clear, with results supporting contributions of both environmental factors and host genetics. To gauge the relative contributions of host genetics and environment, specifically the microbial diversity, we characterized the gut microbiotas of Caenorhabditis species spanning 200-300 million years of evolution, and raised on different composted soil environments. Comparisons were based on 16S rDNA deep sequencing data, as well as on functional evaluation of gut isolates. Worm microbiotas were distinct from those in their respective soil environment, and included bacteria previously identified as part of the C. elegans core microbiota. Microbiotas differed between experiments initiated with different soil communities, but within each experiment, worm microbiotas clustered according to host identity, demonstrating a dominant contribution of environmental diversity, but also a contribution of host genetics. The dominance of environmental contributions hindered identification of host-associated microbial taxa from 16S data. Characterization of gut isolates from C. elegans and C. briggsae, focusing on the core family Enterobacteriaceae, were also unable to expose phylogenetic distinctions between microbiotas of the two species. However, functional evaluation of the isolates revealed host-specific contributions, wherein gut commensals protected their own host from infection, but not a non-host. Identification of commensal host-specificity at the functional level, otherwise overlooked in standard sequence-based analyses, suggests that the contribution of host genetics to shaping of gut microbiotas may be greater than previously realized.

  12. Molecular characterization of host-specific biofilm formation in a vertebrate gut symbiont.

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    Steven A Frese

    Full Text Available Although vertebrates harbor bacterial communities in their gastrointestinal tract whose composition is host-specific, little is known about the mechanisms by which bacterial lineages become selected. The goal of this study was to characterize the ecological processes that mediate host-specificity of the vertebrate gut symbiont Lactobacillus reuteri, and to systematically identify the bacterial factors that are involved. Experiments with monoassociated mice revealed that the ability of L. reuteri to form epithelial biofilms in the mouse forestomach is strictly dependent on the strain's host origin. To unravel the molecular basis for this host-specific biofilm formation, we applied a combination of transcriptome analysis and comparative genomics and identified eleven genes of L. reuteri 100-23 that were predicted to play a role. We then determined expression and importance of these genes during in vivo biofilm formation in monoassociated mice. This analysis revealed that six of the genes were upregulated in vivo, and that genes encoding for proteins involved in epithelial adherence, specialized protein transport, cell aggregation, environmental sensing, and cell lysis contributed to biofilm formation. Inactivation of a serine-rich surface adhesin with a devoted transport system (the SecA2-SecY2 pathway completely abrogated biofilm formation, indicating that initial adhesion represented the most significant step in biofilm formation, likely conferring host specificity. In summary, this study established that the epithelial selection of bacterial symbionts in the vertebrate gut can be both specific and highly efficient, resulting in biofilms that are exclusively formed by the coevolved strains, and it allowed insight into the bacterial effectors of this process.

  13. Strict confluent drawing

    Directory of Open Access Journals (Sweden)

    David Eppstein

    2016-01-01

    Full Text Available We define strict confluent drawing, a form of confluent drawing in which the existence of an edge is indicated by the presence of a smooth path through a system of arcs and junctions (without crossings, and in which such a path, if it exists, must be unique. We prove that it is NP-complete to determine whether a given graph has a strict confluent drawing but polynomial to determine whether it has an outerplanar strict confluent drawing with a fixed vertex ordering (a drawing within a disk, with the vertices placed in a given order on the boundary.

  14. Host specificity of North American Rhabdias spp. (Nematoda: Rhabdiasidae): combining field data and experimental infections with a molecular phylogeny.

    Science.gov (United States)

    Langford, Gabriel J; Janovy, John

    2013-04-01

    Lungworms of the cosmopolitan genus Rhabdias are among the most common parasites of amphibians and squamate reptiles. The present study used experimental infections, field studies, and a molecular phylogeny to determine the host specificity of 6 Rhabdias spp. that infect snakes and anurans from North America. The molecular phylogeny suggests Rhabdias ranae from Nebraska and Mississippi may represent separate, cryptic species. In addition, the phylogeny strongly supports separate clades for anuran and snake lungworms. Field studies and experimental infections indicate that snake lungworms are generalist snake parasites; however, laboratory experiments also suggest that lizards can be infected under some environmental conditions. Lungworms from anurans were found not to infect salamanders or reptiles, in nature or in the laboratory; anuran lungworm species ranged from strict host specificity, e.g., R. ranae from Nebraska, to relative generalist, e.g., Rhabdias joaquinensis from Nebraska. Overall, host specificity for species of Rhabdias does not provide support for the evolution of progressive specialization over time. For most species of lungworms, host specificity in nature appears to be limited by both ecological and physiological factors, which vary between species and their hosts. Furthermore, some lungworms, e.g., Rhabdias bakeri from Missouri, appear to be tracking host resources instead of host phylogenies, an example of ecological fitting.

  15. Symbiotic specificity of tropical tree rhizobia for host legumes

    NARCIS (Netherlands)

    Bala, A.; Giller, K.E.

    2001-01-01

    The host range and specificity is reported of a genetically diverse group of rhizobia isolated from nodules of Calliandra calothyrsus, Gliricidia sepium, Leucaena leucocephala and Sesbania sesban. Nodule number and nitrogen content was measured in seedlings of herbaceous and woody legume species

  16. Host specificity and genealogy of the louse Polyplax serrata on field mice, Apodemus species: a case of parasite duplication or colonisation?

    Science.gov (United States)

    Stefka, Jan; Hypsa, Václav

    2008-05-01

    The genealogy, population structure and population dynamics of the sucking louse Polyplax serrata were analysed across four host species of the genus Apodemus. An analysis of 126 sequences of cytochrome c oxidase subunit I using phylogenetic approaches and haplotype networking revealed a clear structure of European samples, forming three distinct and genetically distant clades with different host specificities. Although a clear connection was detected between the host and parasite genealogies/phylogenies, a uniform pattern of co-speciation was not found. For example, a dramatic shift in the degree of host specificity was demonstrated for two related louse lineages living in sympatry and sharing one of their host species. While one of the louse lineages frequently parasitised two different host taxa (Apodemus sylvaticus and Apodemus flavicollis), the other louse lineage was strictly specific to A. flavicollis. The estimate of divergence time between the two louse lineages indicates that they may have arisen due to parasite duplication on A. flavicollis.

  17. Molecular diversity and host specificity of termite-associated Xylaria.

    Science.gov (United States)

    Guedegbe, Herbert J; Miambi, Edouard; Pando, Anne; Houngnandan, Pascal; Rouland-Lefevre, Corinne

    2009-01-01

    Studies have revealed that some Xylaria species were closely associated with fungus-growing termite nests. However this relationship rarely had been investigated and the host specificity of termite-associated Xylaria was not yet clearly established. Eighteen Xylaria rDNA-ITS sequences were obtained from fungus combs belonging to 11 Macrotermitinae species from eight regions. Low diversity was found between isolates, and nine sequences were retrieved. Termite-associated Xylaria were shown to be monophyletic, with three main clades, all including strains from various termite hosts and geographical localities. This new molecular study shows no species specificity with respect to fungus-growing termites, which suggests that there might be substrate specialization.

  18. Host specificity in a diverse Neotropical tick community: an assessment using quantitative network analysis and host phylogeny

    NARCIS (Netherlands)

    Esser, Helen; Herre, Edward A.; Blüthgen, Nico; Loaiza, Jose R.; Bermúdez, Sergio E.; Jansen, P.A.

    2016-01-01

    Background: Host specificity is a fundamental determinant of tick population and pathogen transmission dynamics, and therefore has important implications for human health. Tick host specificity is expected to be particularly high in the tropics, where communities of ticks, hosts and pathogens are

  19. Strictly convex renormings

    Czech Academy of Sciences Publication Activity Database

    Moltó, A.; Orihuela, J.; Troyanski, S.; Zizler, Václav

    2007-01-01

    Roč. 75, č. 3 (2007), s. 647-658 ISSN 0024-6107 R&D Projects: GA AV ČR IAA100190502 Institutional research plan: CEZ:AV0Z10190503 Keywords : strictly convex norms * lattice norm * quasi-diagonal sets Subject RIV: BA - General Mathematics Impact factor: 0.733, year: 2007

  20. Quine's "Strictly Vegetarian" Analyticity

    NARCIS (Netherlands)

    Decock, L.B.

    2017-01-01

    I analyze Quine’s later writings on analyticity from a linguistic point of view. In Word and Object Quine made room for a “strictly vegetarian” notion of analyticity. In later years, he developed this notion into two more precise notions, which I have coined “stimulus analyticity” and “behaviorist

  1. Diversity and host specificity of the Verminephrobacter–earthworm symbiosis

    DEFF Research Database (Denmark)

    Lund, Marie Braad; Davidson, Seana; Holmstrup, Martin

    2010-01-01

    Symbiotic bacteria of the genus Verminephrobacter (Betaproteobacteria) were detected in the nephridia of 19 out of 23 investigated earthworm species (Oligochaeta: Lumbricidae) by 16S rRNA gene sequence analysis and fluorescence in situ hybridization (FISH). While all four Lumbricus species...... and three out of five Aporrectodea species were densely colonized by a mono-species culture of Verminephrobacter, other earthworm species contained mixed bacterial populations with varying proportions of Verminephrobacter; four species did not contain Verminephrobacter at all. The Verminephrobacter...... symbionts could be grouped into earthworm species-specific sequence clusters based on their 16S rRNA and RNA polymerase subunit B (rpoB) genes. Closely related host species harboured more closely related symbionts than did distantly related hosts. Co-diversification of the symbiotic partners could...

  2. Fluorescent nanodiamond-bacteriophage conjugates maintain host specificity.

    Science.gov (United States)

    Trinh, Jimmy T; Alkahtani, Masfer H; Rampersaud, Isaac; Rampersaud, Arfaan; Scully, Marlan; Young, Ryland F; Hemmer, Philip; Zeng, Lanying

    2018-06-01

    Rapid identification of specific bacterial strains within clinical, environmental, and food samples can facilitate the prevention and treatment of disease. Fluorescent nanodiamonds (FNDs) are being developed as biomarkers in biology and medicine, due to their excellent imaging properties, ability to accept surface modifications, and lack of toxicity. Bacteriophages, the viruses of bacteria, can have exquisite specificity for certain hosts. We propose to exploit the properties of FNDs and phages to develop phages conjugated with FNDs as long-lived fluorescent diagnostic reagents. In this study, we develop a simple procedure to create such fluorescent probes by functionalizing the FNDs and phages with streptavidin and biotin, respectively. We find that the FND-phage conjugates retain the favorable characteristics of the individual components and can discern their proper host within a mixture. This technology may be further explored using different phage/bacteria systems, different FND color centers and alternate chemical labeling schemes for additional means of bacterial identification and new single-cell/virus studies. © 2018 Wiley Periodicals, Inc.

  3. Occurrence and host specificity of a neogregarine protozoan in four milkweed butterfly hosts (Danaus spp.).

    Science.gov (United States)

    Barriga, Paola A; Sternberg, Eleanore D; Lefèvre, Thierry; de Roode, Jacobus C; Altizer, Sonia

    2016-10-01

    Throughout their global range, wild monarch butterflies (Danaus plexippus) are infected with the protozoan Ophryocystis elektroscirrha (OE). In monarchs, OE infection reduces pupal eclosion, adult lifespan, adult body size and flight ability. Infection of other butterfly hosts with OE is rare or unknown, and the only previously published records of OE infection were on monarch and queen butterflies (D. gilippus). Here we explored the occurrence and specificity of OE and OE-like parasites in four Danaus butterfly species. We surveyed wild D. eresimus (soldier), D. gilippus (queen), D. petilia (lesser wanderer), and D. plexippus (monarch) from five countries to determine the presence of infection. We conducted five cross-infection experiments, on monarchs and queen butterflies and their OE and OE-like parasites, to determine infection probability and the impact of infection on their hosts. Our field survey showed that OE-like parasites were present in D. gilippus, D. petilia, and D. plexippus, but were absent in D. eresimus. Infection probability varied geographically such that D. gilippus and D. plexippus populations in Puerto Rico and Trinidad were not infected or had low prevalence of infection, whereas D. plexippus from S. Florida and Australia had high prevalence. Cross-infection experiments showed evidence for host specificity, in that OE strains from monarchs were more effective at infecting monarchs than queens, and monarchs were less likely to be infected by OE-like strains from queens and lesser wanderers relative to their own natal strains. Our study showed that queens are less susceptible to OE and OE-like infection than monarchs, and that the reduction in adult lifespan following infection is more severe in monarchs than in queens. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Parasite performance and host alternation: is there a negative effect in host-specific and host-opportunistic parasites?

    Science.gov (United States)

    VAN DER Mescht, Luther; Khokhlova, Irina S; Warburton, Elizabeth M; Krasnov, Boris R

    2017-07-01

    Environmental fluctuations are expected to require special adaptations only if they are associated with a decrease in fitness. We compared reproductive performance between fleas fed on alternating (preferred and non-preferred) hosts and fleas fed solely on either a preferred or a non-preferred host to determine whether (1) host alternation incurs an immediate negative effect, and, if yes, then (2) whether this effect is greater in a host specialist (Parapulex chephrenis) than in host generalists (Xenopsylla conformis and Synosternus cleopatrae). We also compared flea performance under alternating host regimes with different host order (initial feeding on either a preferred or a non-preferred host). An immediate negative effect of alternating hosts on reproductive performance was found in P. chephrenis only. These fleas produced 44·3% less eggs that were 3·6% smaller when they fed on alternating hosts as compared with a preferred host. In contrast, X. conformis and S. cleopatrae appeared to be able to adapt their reproductive strategy to host alternation by producing higher quality offspring (on average, 3·1% faster development and 2·1% larger size) without compromising offspring number. However, the former produced eggs that were slightly, albeit significantly, smaller when it fed on alternating hosts as compared with a preferred host. Moreover, host order affected reproductive performance in host generalists (e.g. 2·8% larger eggs when the first feeding was performed on a non-preferred host), but not in a host specialist. We conclude that immediate effects of environmental fluctuation on parasite fitness depend on the degree of host specialization.

  5. Cytotoxic T lymphocyte responses in allogeneic radiation bone marrow chimeras. The chimeric host strictly dictates the self-repertoire of Ia-restricted T cells but not H-2K/D-restricted T cells

    International Nuclear Information System (INIS)

    Bradley, S.M.; Kruisbeek, A.M.; Singer, A.

    1982-01-01

    The present report has used fully H-2 allogeneic radiation bone marrow chimeras to assess the role of host restriction elements in determining the self-specificity of Ia- and H-2K/D-restricted T cells that participate in the generation of trinitrophenyl (TNP)-specific cytotoxic T lymphocytes (CTL). It was demonstrated that there exists a stringent requirement for the recognition of host thymic-type Ia determinants, but there exists only a preference for host thymic-type H-2K/D determinants. Indeed, once the stringent requirement for recognition of host Ia determinants was fulfilled, anti-TNP CTL were generated in response to TNP-modified stimulators that expressed either donor-type or host-type H-2K/D determinants. The CTL that were generated in response to TNP-modified donor-type stimulators were shown to be specific for TNP and restricted to the non-thymic H-2K/D determinants of the chimeric donor. Thus, these results demonstrate in a single immune response that the thymic hypothesis accurately predicts the self-specificity expressed by Ia-restricted T cells, but does not fully account for the self-specificity expressed by H-2K/D-restricted T cells. These results are consistent with the concept that H-2K/D-restricted T cells, but not Ia-restricted T cells, can differentiate into functional competence either intrathymically or extra-thymically. The results demonstrate that the generation of anti-TNP CTL responses involve two parallel sets of major histocompatibility complex-restricted cell interactions, an Ia-restricted TH-accessory cell interaction required for TH cell activation, and an H-2K/D-restricted pCTL-stimulator cell interaction required for pCTL stimulation. The interaction between activated TH cells and stimulated pCTL is mediated, at least in part, by nonspecific soluble helper factors

  6. Flexible or Strict Taxonomic Organization?

    DEFF Research Database (Denmark)

    Glückstad, Fumiko Kano; Mørup, Morten

    2012-01-01

    This work compares methods for constructing feature-based ontologies that are supposed to be used for culturally-specific knowledge transfer. The methods to be compared are the Terminological Ontology (TO) [1], a method of constructing ontology based on strict principles and rules, and the Infinite...... Relational Model (IRM) [2], a novel unsupervised machine learning method that learns multi-dimensional relations among concepts and features from loosely structured datasets. These methods are combined with a novel cognitive model, the Bayesian Model of Generalization (BMG) [3] that maps culturally...

  7. Host Specificity and Temporal and Seasonal Shifts in Host Preference of a Web-Spider Parasitoid Zatypota percontatoria

    OpenAIRE

    Korenko, Stanislav; Michalková, Veronika; Zwakhals, Kees; Pekár, Stano

    2011-01-01

    Current knowledge about polysphinctine parasite wasps' interactions with their spider hosts is very fragmented and incomplete. This study presents the host specificity of Zatypota percontatoria (Müller) (Hymenoptera: Ichneumonidae) and its adaptation to varying host availability. Two years of field observations show that Z. percontatoria is a stenophagous parasitoid that parasitizes only five closely related web-building spiders of the family Theridiidae (Araneae). Within the Theridiidae it a...

  8. Ancient host specificity within a single species of brood parasitic bird.

    Science.gov (United States)

    Spottiswoode, Claire N; Stryjewski, Katherine Faust; Quader, Suhel; Colebrook-Robjent, John F R; Sorenson, Michael D

    2011-10-25

    Parasites that exploit multiple hosts often experience diversifying selection for host-specific adaptations. This can result in multiple strains of host specialists coexisting within a single parasitic species. A long-standing conundrum is how such sympatric host races can be maintained within a single parasitic species in the face of interbreeding among conspecifics specializing on different hosts. Striking examples are seen in certain avian brood parasites such as cuckoos, many of which show host-specific differentiation in traits such as host egg mimicry. Exploiting a Zambian egg collection amassed over several decades and supplemented by recent fieldwork, we show that the brood parasitic Greater Honeyguide Indicator indicator exhibits host-specific differentiation in both egg size and egg shape. Genetic analysis of honeyguide eggs and chicks show that two highly divergent mitochondrial DNA lineages are associated with ground- and tree-nesting hosts, respectively, indicating perfect fidelity to two mutually exclusive sets of host species for millions of years. Despite their age and apparent adaptive diversification, however, these ancient lineages are not cryptic species; a complete lack of differentiation in nuclear genes shows that mating between individuals reared by different hosts is sufficiently frequent to prevent speciation. These results indicate that host specificity is maternally inherited, that host-specific adaptation among conspecifics can be maintained without reproductive isolation, and that host specificity can be remarkably ancient in evolutionary terms.

  9. Experimental test of host specificity in a behaviour-modifying trematode

    DEFF Research Database (Denmark)

    Hernandez, R.N.; Fredensborg, Brian Lund

    2015-01-01

    Host behavioural modification by parasites is a common and well-documented phenomenon. However, knowledge on the complexity and specificity of the underlying mechanisms is limited, and host specificity among manipulating parasites has rarely been experimentally verified. We tested the hypothesis ...... controls. Euhaplorchis sp. A was able to infect and manipulate fish belonging to two different families, suggesting that ecological similarity rather than genetic relatedness determines host range in this species.......Host behavioural modification by parasites is a common and well-documented phenomenon. However, knowledge on the complexity and specificity of the underlying mechanisms is limited, and host specificity among manipulating parasites has rarely been experimentally verified. We tested the hypothesis...... that the ability to infect and manipulate host behaviour is restricted to phylogenetically closely related hosts. Our model system consisted of the brain-encysting trematode Euhaplorchis sp. A and six potential fish intermediate hosts from the Order Cyprinodontiformes. Five co-occurring cyprinids were examined...

  10. Geographical variation in host-ant specificity of the parasitic butterfly Maculinea alcon in Denmark

    DEFF Research Database (Denmark)

    Als, Thomas Damm; Nash, David Richard; Boomsma, J. J.

    2002-01-01

    to be a more suitable host in populations where two host species are used simultaneously. Host-ant species has an influence on caterpillar size but this varies geographically. Analyses of pupae did not, however, show size differences between M. alcon raised in M. rubra and M. ruginodis nests.5....... The geographical mosaic of host specificity and demography of M. alcon in Denmark probably reflects the co-evolution of M. alcon with two alternative host species. This system therefore provides an interesting opportunity for studying details of the evolution of parasite specificity and the dynamics of host...

  11. Evolution and host specificity in the ectomycorrhizal genus Leccinum

    NARCIS (Netherlands)

    Bakker, den H.C.; Zuccarello, G.C.; Kuyper, T.W.; Noordeloos, M.E.

    2004-01-01

    Species of the ectomycorrhizal genus Leccinum are generally considered to be host specialists. We determined the phylogenetic relationships between species of Leccinum from Europe and North America based on second internal transcribed spacer (ITS2) and glyceraldehyde 3-phosphate dehydrogenase

  12. Comparative Methods for Molecular Determination of Host-Specificity Factors in Plant-Pathogenic Fungi

    Directory of Open Access Journals (Sweden)

    Nilam Borah

    2018-03-01

    Full Text Available Many plant-pathogenic fungi are highly host-specific. In most cases, host-specific interactions evolved at the time of speciation of the respective host plants. However, host jumps have occurred quite frequently, and still today the greatest threat for the emergence of new fungal diseases is the acquisition of infection capability of a new host by an existing plant pathogen. Understanding the mechanisms underlying host-switching events requires knowledge of the factors determining host-specificity. In this review, we highlight molecular methods that use a comparative approach for the identification of host-specificity factors. These cover a wide range of experimental set-ups, such as characterization of the pathosystem, genotyping of host-specific strains, comparative genomics, transcriptomics and proteomics, as well as gene prediction and functional gene validation. The methods are described and evaluated in view of their success in the identification of host-specificity factors and the understanding of their functional mechanisms. In addition, potential methods for the future identification of host-specificity factors are discussed.

  13. Host specificity and temporal and seasonal shifts in host preference of a web-spider parasitoid Zatypota percontatoria.

    Science.gov (United States)

    Korenko, Stanislav; Michalková, Veronika; Zwakhals, Kees; Pekár, Stano

    2011-01-01

    Current knowledge about polysphinctine parasite wasps' interactions with their spider hosts is very fragmented and incomplete. This study presents the host specificity of Zatypota percontatoria (Müller) (Hymenoptera: Ichneumonidae) and its adaptation to varying host availability. Two years of field observations show that Z. percontatoria is a stenophagous parasitoid that parasitizes only five closely related web-building spiders of the family Theridiidae (Araneae). Within the Theridiidae it attacks only species belonging to a small group of species, here called the "Theridion" group. These hosts have a similar biology, but are available at different levels of abundance and at different sizes over the season. Laboratory experiments showed that this wasp species ignores linyphiid, araneid or dictynid spiders and accepts only theridiid spiders of the "Theridion" group. In the field study, wasp females preferred older juvenile and sub-adult female spider instars with intermediate body size. Only 5% of the parasitized spiders were males. Parasitism in the natural population of theridiid spiders was on average 1.3%. Parasitism was most frequent on two species, Theridion varians Hahn in 2007 and Neottiura bimaculata Linnaeus in 2008. The parasitization rate was positively correlated with spider abundance. The wasp responded adaptively to seasonal changes in host abundance and host body size and shifted host preference according to the availability of suitable hosts during, as well as between, seasons. In spring and summer the highest percentage of parasitism was on T. varians and in autumn it was on N. bimaculata.

  14. Host-specific races in the holoparasitic angiosperm Orobanche minor: implications for speciation in parasitic plants.

    Science.gov (United States)

    Thorogood, C J; Rumsey, F J; Hiscock, S J

    2009-05-01

    Orobanche minor is a root-holoparasitic angiosperm that attacks a wide range of host species, including a number of commonly cultivated crops. The extent to which genetic divergence among natural populations of O. minor is influenced by host specificity has not been determined previously. Here, the host specificity of natural populations of O. minor is quantified for the first time, and evidence that this species may comprise distinct physiological races is provided. A tripartite approach was used to examine the physiological basis for the divergence of populations occurring on different hosts: (1) host-parasite interactions were cultivated in rhizotron bioassays in order to quantify the early stages of the infection and establishment processes; (2) using reciprocal-infection experiments, parasite races were cultivated on their natural and alien hosts, and their fitness determined in terms of biomass; and (3) the anatomy of the host-parasite interface was investigated using histochemical techniques, with a view to comparing the infection process on different hosts. Races occurring naturally on red clover (Trifolium pratense) and sea carrot (Daucus carota ssp. gummifer) showed distinct patterns of host specificity: parasites cultivated in cross-infection studies showed a higher fitness on their natural hosts, suggesting that races show local adaptation to specific hosts. In addition, histological evidence suggests that clover and carrot roots vary in their responses to infection. Different root anatomy and responses to infection may underpin a physiological basis for host specificity. It is speculated that host specificity may isolate races of Orobanche on different hosts, accelerating divergence and ultimately speciation in this genus. The rapid life cycle and broad host range of O. minor make this species an ideal model with which to study the interactions of parasitic plants with their host associates.

  15. Purification and host specificity of predatory halobacteriovorax isolated from seawater

    Science.gov (United States)

    Halobacteriovorax (formerly Bacteriovorax) are small predatory bacteria found in the marine environment and may serve as biocontrol agents against pathogens in fish and shellfish. Four strains of Halobacteriovorax originally isolated in Vibrio parahaemolyticus O3:K6 host cells were separated from t...

  16. Efficient Strictness Analysis of Haskell

    DEFF Research Database (Denmark)

    Jensen, Kristian Damm; Hjæresen, Peter; Rosendahl, Mads

    1994-01-01

    Strictness analysis has been a living field of investigation since Mycroft's original work in 1980, and is getting increasingly significant with the still wider use of lazy functional programming languages. This paper focuses on an actual implementation of a strictness analyser for Haskell...

  17. Relationships among different facets of host specificity in three taxa of haematophagous ectoparasites.

    Science.gov (United States)

    van der Mescht, Luther; Warburton, Elizabeth M; Khokhlova, Irina S; Vinarski, Maxim V; Korallo-Vinarskaya, Natalia P; Krasnov, Boris R

    2017-12-01

    Host specificity is a fundamental trait of a parasite species. Recently, multiple aspects of host specificity have been recognized, but the relationships between these facets are still poorly understood. Here, we studied pairwise relationships between basic, structural, phylogenetic and geographic host specificity in three taxa of haematophagous ectoparasitic arthropods that differ in tightness of their association with the host. We asked which metrics of host specificity are correlated within each parasite taxon and whether the patterns of the association between different facets of host specificity are similar among parasite taxa. Data on bat flies were taken from published surveys across the Neotropics while data on fleas and mites parasitic on small mammals were compiled from multiple published surveys across the Palaearctic. Basic, structural, phylogenetic and geographic specificity indices were calculated for 18 bat fly species recorded on 40 host species from 15 regions, 109 flea species recorded on 120 host species from 51 regions and 34 mite species recorded on 67 host species from 28 regions. Then, we tested for the correlation between any two measures of host specificity using model II regressions. We found that structural and basic specificity, as well as structural and geographic specificity, exhibited a positive association in all three taxa. However, basic and geographic specificity, as well as basic and phylogenetic specificity, were significantly positively associated in fleas but did not correlate in bat flies or mites. In addition, we found a significant negative association between structural and phylogenetic specificity in bat flies but no association in the remaining taxa. Moreover, geographic and phylogenetic specificity were not associated in any parasite taxon. Our results suggest that different facets of host specificity were shaped differently by natural selection in different taxa. Copyright © 2017 Australian Society for Parasitology

  18. Review - Host specificity of insect herbivores in tropical forests

    Czech Academy of Sciences Publication Activity Database

    Novotný, Vojtěch; Basset, Y.

    2005-01-01

    Roč. 272, č. 1568 (2005), s. 1083-1090 ISSN 0962-8452 R&D Projects: GA AV ČR(CZ) IAA6007106; GA ČR(CZ) GD206/03/H034; GA ČR(CZ) GA206/04/0725; GA MŠk(CZ) ME 646 Grant - others:US Nationals Science Foundation(US) DEB-02-11591; Darwin Initiative for the Survival of Species(US) 162/10/030 Institutional research plan: CEZ:AV0Z50070508 Keywords : food web * herbivore guild * host plant range Subject RIV: EH - Ecology, Behaviour Impact factor: 3.510, year: 2005

  19. Host strain specific sex pheromone variation in Spodoptera frugiperda

    Directory of Open Access Journals (Sweden)

    Svatos Ales

    2008-12-01

    Full Text Available Abstract Background The fall armyworm Spodoptera frugiperda (Lepidoptera; Noctuidae consists of two distinct strains with different host plant preferences for corn and rice. To assess whether pheromonal-mediated behavioral isolation accompanies the habitat isolation on different host plants, we compared the sex pheromone composition among females of the two strains. Pheromone glands were extracted with or without injection of pheromone biosynthesis activating neuropeptide (PBAN. To assess the mode of inheritance of this variation, we also analyzed the pheromone composition of F1 hybrid females. Results Relative to intra-strain variation, the pheromone composition of the two strains differed significantly. Corn strain females contained significantly more of the second most abundant pheromone compound Z11-16:Ac (m, and significantly less of most other compounds, than rice strain females. When females were injected with PBAN before their glands were extracted, the differences between the strains were less pronounced but still statistically significant. The pheromone composition of hybrid females showed a maternal inheritance of the major component Z9-14:Ac (M as well as of Z11-16:Ac (m. Most other compounds showed an inheritance indicating genetic dominance of the corn strain. The within-strain phenotypic correlations among the various components were consistent with their hypothesized biosynthetic pathway, and between-strain differences in the correlation structure suggested candidate genes that may explain the pheromone differences between the two strains. These include Δ9- and Δ11 desaturases, and possibly also a Δ7-desaturase, although the latter has not been identified in insects so far. Conclusion The two host strains of S. frugiperda produce systematically differing female sex pheromone blends. Previously-documented geographic variation in the sexual communication of this species did not take strain identity into account, and thus may be

  20. Sex-specific effects of a parasite evolving in a female-biased host population

    Directory of Open Access Journals (Sweden)

    Duneau David

    2012-12-01

    Full Text Available Abstract Background Males and females differ in many ways and might present different opportunities and challenges to their parasites. In the same way that parasites adapt to the most common host type, they may adapt to the characteristics of the host sex they encounter most often. To explore this hypothesis, we characterized host sex-specific effects of the parasite Pasteuria ramosa, a bacterium evolving in naturally, strongly, female-biased populations of its host Daphnia magna. Results We show that the parasite proliferates more successfully in female hosts than in male hosts, even though males and females are genetically identical. In addition, when exposure occurred when hosts expressed a sexual dimorphism, females were more infected. In both host sexes, the parasite causes a similar reduction in longevity and leads to some level of castration. However, only in females does parasite-induced castration result in the gigantism that increases the carrying capacity for the proliferating parasite. Conclusions We show that mature male and female Daphnia represent different environments and reveal one parasite-induced symptom (host castration, which leads to increased carrying capacity for parasite proliferation in female but not male hosts. We propose that parasite induced host castration is a property of parasites that evolved as an adaptation to specifically exploit female hosts.

  1. Geographical variation in host-ant specificity of the parasitic butterfly Maculinea alcon in Denmark

    DEFF Research Database (Denmark)

    Als, Thomas Damm; Nash, David Richard; Boomsma, J. J.

    2002-01-01

    1. Maculinea alcon uses three different species of Myrmica host ants along a north-south gradient in Europe. Based on this geographical variation in host ant use, Elmes et al. (1994) suggested that M. alcon might consist of three or more cryptic species or host races, each using a single and diff......1. Maculinea alcon uses three different species of Myrmica host ants along a north-south gradient in Europe. Based on this geographical variation in host ant use, Elmes et al. (1994) suggested that M. alcon might consist of three or more cryptic species or host races, each using a single...... and different host-ant species.2. Population-specific differences in allozyme genotypes of M. alcon in Denmark (Gadeberg Boomsma, 1997) have suggested that genetically differentiated forms may occur in a gradient across Denmark, possibly in relation to the use of different host ants.3. It was found that two....... The geographical mosaic of host specificity and demography of M. alcon in Denmark probably reflects the co-evolution of M. alcon with two alternative host species. This system therefore provides an interesting opportunity for studying details of the evolution of parasite specificity and the dynamics of host-race...

  2. Geographically structured host specificity is caused by the range expansions and host shifts of a symbiotic fungus.

    Science.gov (United States)

    Wolfe, Benjamin E; Pringle, Anne

    2012-04-01

    The inability to associate with local species may constrain the spread of mutualists arriving to new habitats, but the fates of introduced, microbial mutualists are largely unknown. The deadly poisonous ectomycorrhizal fungus Amanita phalloides (the death cap) is native to Europe and introduced to the East and West Coasts of North America. By cataloging host associations across the two continents, we record dramatic changes in specificity among the three ranges. On the East Coast, where the fungus is restricted in its distribution, it associates almost exclusively with pines, which are rarely hosts of A. phalloides in its native range. In California, where the fungus is widespread and locally abundant, it associates almost exclusively with oaks, mirroring the host associations observed in Europe. The most common host of the death cap in California is the endemic coast live oak (Quercus agrifolia), and the current distribution of A. phalloides appears constrained within the distribution of Q. agrifolia. In California, host shifts to native plants are also associated with a near doubling in the resources allocated to sexual reproduction and a prolonged fruiting period; mushrooms are twice as large as they are elsewhere and mushrooms are found throughout the year. Host and niche shifts are likely to shape the continuing range expansion of A. phalloides and other ectomycorrhizal fungi introduced across the world.

  3. The Trw type IV secretion system of Bartonella mediates host-specific adhesion to erythrocytes.

    Directory of Open Access Journals (Sweden)

    Muriel Vayssier-Taussat

    2010-06-01

    Full Text Available Bacterial pathogens typically infect only a limited range of hosts; however, the genetic mechanisms governing host-specificity are poorly understood. The alpha-proteobacterial genus Bartonella comprises 21 species that cause host-specific intraerythrocytic bacteremia as hallmark of infection in their respective mammalian reservoirs, including the human-specific pathogens Bartonella quintana and Bartonella bacilliformis that cause trench fever and Oroya fever, respectively. Here, we have identified bacterial factors that mediate host-specific erythrocyte colonization in the mammalian reservoirs. Using mouse-specific Bartonella birtlesii, human-specific Bartonella quintana, cat-specific Bartonella henselae and rat-specific Bartonella tribocorum, we established in vitro adhesion and invasion assays with isolated erythrocytes that fully reproduce the host-specificity of erythrocyte infection as observed in vivo. By signature-tagged mutagenesis of B. birtlesii and mutant selection in a mouse infection model we identified mutants impaired in establishing intraerythrocytic bacteremia. Among 45 abacteremic mutants, five failed to adhere to and invade mouse erythrocytes in vitro. The corresponding genes encode components of the type IV secretion system (T4SS Trw, demonstrating that this virulence factor laterally acquired by the Bartonella lineage is directly involved in adherence to erythrocytes. Strikingly, ectopic expression of Trw of rat-specific B. tribocorum in cat-specific B. henselae or human-specific B. quintana expanded their host range for erythrocyte infection to rat, demonstrating that Trw mediates host-specific erythrocyte infection. A molecular evolutionary analysis of the trw locus further indicated that the variable, surface-located TrwL and TrwJ might represent the T4SS components that determine host-specificity of erythrocyte parasitism. In conclusion, we show that the laterally acquired Trw T4SS diversified in the Bartonella lineage

  4. Comparative transcriptomics reveal host-specific nucleotide variation in entomophthoralean fungi

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Jensen, Annette Bruun; Eilenberg, Jørgen

    2017-01-01

    of toxins that interfere with the host immune response. Phylogenetic comparison with the nonobligate generalist insect-pathogenic fungus Conidiobolus coronatus revealed a gene-family expansion of trehalase enzymes in E. muscae. The main sugar in insect haemolymph is trehalose, and efficient sugar......Obligate parasites are under strong selection to increase exploitation of their host to survive while evading detection by host immune defences. This has often led to elaborate pathogen adaptations and extreme host specificity. Specialization on one host, however, often incurs a trade......-off influencing the capacity to infect alternate hosts. Here, we investigate host adaptation in two morphologically indistinguishable and closely related obligate specialist insect-pathogenic fungi from the phylum Entomophthoromycota, Entomophthora muscae sensu stricto and E. muscae sensu lato, pathogens...

  5. Evidence for mating between isolates of Colletotrichum gloeosporioides with different host specificities.

    Science.gov (United States)

    Cisar, C R; Spiegel, F W; TeBeest, D O; Trout, C

    1994-04-01

    Individual isolates of the ubiquitous plant pathogen Colletotrichum gloeosporioides (teleomorph Glomerella cingulata) can have very restricted host ranges. Isolates that share the same host range are considered to be genetically discrete units, and sexual compatibility has been reported to be limited to individuals that share the same host range. However, we have recently observed that some isolates of C. gloeosporioides that are specifically pathogenic to different, distantly-related hosts are sexually compatible. Ascospore progeny from one such cross were randomly isolated and outcrossing was verified by the reassortment of several RFLP markers among the progeny. In addition, the progeny were analyzed for pathogenicity to parental hosts. The implications of sexual compatibility between C. gloeosporioides isolates with different host specificities on the evolution of Colletotrichum species are discussed.

  6. Species Protection in the European Union : How Strict is Strict?

    NARCIS (Netherlands)

    Schoukens, Hendrik; Bastmeijer, Kees; Born et al., Charles-Hubert

    2015-01-01

    European Union law to protect wild species of plants and animals is generally considered as ‘strict’. Opponents of nature conservation law often pick the species protection components of the EU Bird Directive and Habitat Directive as a prime example of an unnecessary strict regulatory scheme that

  7. Ectomycorrhizal host specificity in a changing world: can legacy effects explain anomalous current associations?

    Science.gov (United States)

    Lofgren, Lotus; Nguyen, Nhu H; Kennedy, Peter G

    2018-02-07

    Despite the importance of ectomycorrhizal (ECM) fungi in forest ecosystems, knowledge about the ecological and co-evolutionary mechanisms underlying ECM host associations remains limited. Using a widely distributed group of ECM fungi known to form tight associations with trees in the family Pinaceae, we characterized host specificity among three unique Suillus-host species pairs using a combination of field root tip sampling and experimental bioassays. We demonstrate that the ECM fungus S. subaureus can successfully colonize Quercus hosts in both field and glasshouse settings, making this species unique in an otherwise Pinaceae-specific clade. Importantly, however, we found that the colonization of Quercus by S. subaureus required co-planting with a Pinaceae host. While our experimental results indicate that gymnosperms are required for the establishment of new S. subaureus colonies, Pineaceae hosts are locally absent at both our field sites. Given the historical presence of Pineaceae hosts before human alteration, it appears the current S. subaureus-Quercus associations represent carryover from past host presence. Collectively, our results suggest that patterns of ECM specificity should be viewed not only in light of current forest community composition, but also as a legacy effect of host community change over time. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

  8. Host specificity, molecular phylogeny and morphological differences of Phyllodistomum pseudofolium Nybelin, 1926 and Phyllodistomum angulatum Linstow, 1907 (Trematoda: Gorgoderidae) with notes on Eurasian ruffe as final host for Phyllodistomum spp.

    Science.gov (United States)

    Stunžėnas, Virmantas; Petkevičiūtė, Romualda; Poddubnaya, Larisa G; Stanevičiūtė, Gražina; Zhokhov, Alexander E

    2017-06-06

    Host-specificity patterns are not well-defined for trematodes of the genus Phyllodistomum Braun, 1899. The Eurasian ruffe, Gymnocephalus cernuus L., has been recorded as a definitive host for Phyllodistomum folium (Olfers, 1816), P. angulatum Linstow, 1907 and P. megalorchis Nybelin, 1926 and as the type-host for P. pseudofolium Nybelin (1926). A wide range of other host fishes have been recorded for these species as well. All present host records have been based on light microscopy and the life-cycles of P. pseudofolium, P. angulatum and P. megalorchis are unknown. The validity of P. pseudofolium and P. megalorchis require verification. In this study, rDNA sequences generated from adult Phyllodistomum spp., as well as from larval stages developing in Pisidium amnicum Müller, were analysed to establish the real number of Phyllodistomum species utilizing G. cernuus, and to associate larvae with the corresponding adult forms. Phylogenetic analyses of adult and larval stages of Phyllodistomum spp. based on ITS2 and partial 28S rDNA data allowed the confirmation of the validity of P. pseudofolium. A macrocercous cercaria, known as Phyllodistomum sp. from P. amnicum is genetically identical to adult P. pseudofolium. Phyllodistomum megalorchis obtained from its type-host, Lota lota L., showed no genetic differences from P. angulatum parasitizing Sander lucioperca L. In our analysis, P. pseudofolium, P. angulatum and P. macrocotyle formed a highly supported clade despite the fact that these species appear to be associated with distinct patterns of first intermediate host identity and cercarial morphology. Some morphological differences between gravid specimens of P. pseudofolium and P. angulatum were observed and their SEM tegumental surface topography is described. The results lead us to the perception that macroevolutionary host switching in the genus Phyllodistomum is independent of host phylogeny. This study suggests strict host-specificity (oioxeny) for P

  9. R gene-controlled host specificity in the legume-rhizobia symbiosis

    Science.gov (United States)

    Leguminous plants can enter into root nodule symbioses with nitrogen-fixing soil bacteria known as rhizobia. An intriguing but still poorly understood property of the symbiosis is its host specificity, which is controlled at multiple levels involving both rhizobial and host genes. Here we report the...

  10. Solenopsis invicta virus 3: Further host-specificity tests with native Solenopsis ants (Hymenoptera: Formicidae)

    Science.gov (United States)

    A thorough understanding of host specificity is essential before pathogens can be used as biopesticides or self-sustaining biocontrol agents. In order to better define the host range of the recently discovered Solenopsis invicta virus 3 (SINV-3), we collected and exposed colonies of two native fire...

  11. Cryptic diversity, high host specificity and reproductive synchronization in army ant-associated Vatesus beetles.

    Science.gov (United States)

    von Beeren, Christoph; Maruyama, Munetoshi; Kronauer, Daniel J C

    2016-02-01

    Army ants and their arthropod symbionts represent one of the most species-rich animal associations on Earth, and constitute a fascinating example of diverse host-symbiont interaction networks. However, despite decades of research, our knowledge of army ant symbionts remains fragmentary due to taxonomic ambiguity and the inability to study army ants in the laboratory. Here, we present an integrative approach that allows us to reliably determine species boundaries, assess biodiversity, match different developmental stages and sexes, and to study the life cycles of army ant symbionts. This approach is based on a combination of community sampling, DNA barcoding, morphology and physiology. As a test case, we applied this approach to the staphylinid beetle genus Vatesus and its different Eciton army ant host species at La Selva Biological Station, Costa Rica. DNA barcoding led to the discovery of cryptic biodiversity and, in combination with extensive community sampling, revealed strict host partitioning with no overlap in host range. Using DNA barcoding, we were also able to match the larval stages of all focal Vatesus species. In combination with studies of female reproductive physiology, this allowed us to reconstruct almost the complete life cycles of the different beetle species. We show that Vatesus beetles are highly adapted to the symbiosis with army ants, in that their reproduction and larval development are synchronized with the stereotypical reproductive and behavioural cycles of their host colonies. Our approach can now be used to study army ant-symbiont communities more broadly, and to obtain novel insights into co-evolutionary and ecological dynamics in species-rich host-symbiont systems. © 2015 John Wiley & Sons Ltd.

  12. Host specificity shapes population structure of pinworm parasites in Caribbean reptiles.

    Science.gov (United States)

    Falk, Bryan G; Perkins, Susan L

    2013-09-01

    Host specificity is one of the potential factors affecting parasite diversification because gene flow may be facilitated or constrained by the number of host species that a parasite can exploit. We test this hypothesis using a costructure approach, comparing two sympatric pinworm parasites that differ in host specificity - Parapharyngodon cubensis and Spauligodon anolis - on the Puerto Rican Bank and St. Croix in the Caribbean. Spauligodon anolis specializes on Anolis lizards, whereas P. cubensis parasitizes Anolis lizards as well as many other species of lizards and snakes. We collected lizards from across the Puerto Rican Bank and St. Croix, sampled them for S. anolis and P. cubensis and generated nuclear and mitochondrial sequence data from the parasites. We used these data to show that P. cubensis is comprised of multiple cryptic species that exhibit limited population structure relative to S. anolis, which is consistent with our prediction based on their host specificity. We also provide evidence that the distribution of P. cubensis species is maintained by competitive exclusion, and in contrast to previous theoretical work, the parasites with the greatest number of host species also reach the highest prevalence rates. Overall, our results are consistent with the hypothesis that host specificity shapes parasite diversification, and suggest that even moderate differences in host specificity may contribute to substantial differences in diversification. © 2013 John Wiley & Sons Ltd.

  13. Unravelling mummies: cryptic diversity, host specificity, trophic and coevolutionary interactions in psyllid - parasitoid food webs.

    Science.gov (United States)

    Hall, Aidan A G; Steinbauer, Martin J; Taylor, Gary S; Johnson, Scott N; Cook, James M; Riegler, Markus

    2017-06-06

    Parasitoids are hyperdiverse and can contain morphologically and functionally cryptic species, making them challenging to study. Parasitoid speciation can arise from specialisation on niches or diverging hosts. However, which process dominates is unclear because cospeciation across multiple parasitoid and host species has rarely been tested. Host specificity and trophic interactions of the parasitoids of psyllids (Hemiptera) remain mostly unknown, but these factors are fundamentally important for understanding of species diversity, and have important applied implications for biological control. We sampled diverse parasitoid communities from eight Eucalyptus-feeding psyllid species in the genera Cardiaspina and Spondyliaspis, and characterised their phylogenetic and trophic relationships using a novel approach that forensically linked emerging parasitoids with the presence of their DNA in post-emergence insect mummies. We also tested whether parasitoids have cospeciated with their psyllid hosts. The parasitoid communities included three Psyllaephagus morphospecies (two primary and, unexpectedly, one heteronomous hyperparasitoid that uses different host species for male and female development), and the hyperparasitoid, Coccidoctonus psyllae. However, the number of genetically delimited Psyllaephagus species was three times higher than the number of recognisable morphospecies, while the hyperparasitoid formed a single generalist species. In spite of this, cophylogenetic analysis revealed unprecedented codivergence of this hyperparasitoid with its primary parasitoid host, suggesting that this single hyperparasitoid species is possibly diverging into host-specific species. Overall, parasitoid and hyperparasitoid diversification was characterised by functional conservation of morphospecies, high host specificity and some host switching between sympatric psyllid hosts. We conclude that host specialisation, host codivergence and host switching are important factors driving

  14. Host-feeding behaviour of Dermacentor reticulatus and Dermacentor marginatus in mono-specific and inter-specific infestations.

    Science.gov (United States)

    Buczek, Alicja; Bartosik, Katarzyna; Zając, Zbigniew; Stanko, Michał

    2015-09-17

    Given the sympatric occurrence in some regions of Europe and the great epidemiological significance of D. reticulatus and D. marginatus species, we investigated the behaviour of these ticks during inter-specific and mono-specific host infestations. The investigations were conducted on rabbits at 20 ± 3 °C and humidity of 38 ± 1 %. The inter-specific infestations groups consisted of 20 females and ten males of D. marginatus and 20 females and ten males of D. reticulatus on each host, whereas mono-specific infestations involved 40 females and 20 males of each species. The investigations have demonstrated competition between the two tick species resulting in modification of the behaviour on the host and the feeding course in D. marginatus females by the presence of D. reticulatus. In the inter-specific group, D. marginatus females attached for a longer time (mean 2.74 ± 1.12 h) than in the mono-specific group (mean 1.24 ± 0.97 h) (p mono-specific group (13.15 ± 2.53 days) (p mono-specific infestation (p = 0.0155). In D. reticulatus females, no significant difference was found in the host attachment and feeding rates between the mono-specific and inter-specific groups. The differences in the behaviour of the females from both species during co-feeding reflect physiological adaptation to environmental conditions, which enables them to ingest blood and reproduce. During co-feeding of D. reticulatus and D. marginatus on the same host, two inter-specific systems with different physiological features are formed, which may influence the transmission of tick-borne pathogens.

  15. Phylogeny of Cirsium spp. in North America: Host Specificity Does Not Follow Phylogeny

    Directory of Open Access Journals (Sweden)

    Tracey A. Bodo Slotta

    2012-10-01

    Full Text Available Weedy invasive Cirsium spp. are widespread in temperate regions of North America and some of their biological control agents have attacked native Cirsium spp. A phylogenetic tree was developed from DNA sequences for the internal transcribed spacer and external transcribed spacer regions from native and non-native Great Plains Cirsium spp. and other thistles to determine if host specificity follows phylogeny. The monophyly of Cirsium spp. and Carduus within the tribe Cardinae was confirmed with native North American and European lineages of the Cirsium spp. examined. We did not detect interspecific hybridization between the introduced invasive and the native North American Cirsium spp. Selected host-biological control agent interactions were mapped onto the phylogenic tree derived by maximum likelihood analysis to examine the co-occurrence of known hosts with biological control agents. Within Cirsium-Cardueae, the insect biological control agents do not associate with host phylogenetic lines. Thus, more comprehensive testing of species in host-specificity trials, rather than relying on a single representative of a given clade may be necessary; because the assumption that host-specificity follows phylogeny does not necessarily hold. Since the assumption does not always hold, it will also be important to evaluate ecological factors to provide better cues for host specificity.

  16. Species-specific genes under selection characterize the co-evolution of slavemaker and host lifestyles.

    Science.gov (United States)

    Feldmeyer, B; Elsner, D; Alleman, A; Foitzik, S

    2017-12-04

    selection in each species. These results point to species-specific adaptations rather than convergent trajectories during the evolution of the slavemaker and host lifestyles suggesting that the evolution of parasitism, even in closely related species, may be achieved in diverse ways.

  17. Cryptic host-specific diversity among western hemisphere broomrapes (Orobanche s.l., Orobanchaceae).

    Science.gov (United States)

    Schneider, Adam C; Colwell, Alison E L; Schneeweiss, Gerald M; Baldwin, Bruce G

    2016-11-01

    The broomrapes, Orobanche sensu lato (Orobanchaceae), are common root parasites found across Eurasia, Africa and the Americas. All species native to the western hemisphere, recognized as Orobanche sections Gymnocaulis and Nothaphyllon, form a clade that has a centre of diversity in western North America, but also includes four disjunct species in central and southern South America. The wide ecological distribution coupled with moderate taxonomic diversity make this clade a valuable model system for studying the role, if any, of host-switching in driving the diversification of plant parasites. Two spacer regions of ribosomal nuclear DNA (ITS + ETS), three plastid regions and one low-copy nuclear gene were sampled from 163 exemplars of Orobanche from across the native geographic range in order to infer a detailed phylogeny. Together with comprehensive data on the parasites' native host ranges, associations between phylogenetic lineages and host specificity are tested. Within the two currently recognized species of O. sect. Gymnocaulis, seven strongly supported clades were found. While commonly sympatric, members of these clades each had unique host associations. Strong support for cryptic host-specific diversity was also found in sect. Nothaphyllon, while other taxonomic species were well supported. We also find strong evidence for multiple amphitropical dispersals from central North America into South America. Host-switching is an important driver of diversification in western hemisphere broomrapes, where host specificity has been grossly underestimated. More broadly, host specificity and host-switching probably play fundamental roles in the speciation of parasitic plants. © The Author 2016. Published by Oxford University Press on behalf of the Annals of Botany Company. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  18. Strictness Analysis for Attribute Grammars

    DEFF Research Database (Denmark)

    Rosendahl, Mads

    1992-01-01

    interpretation of attribute grammars. The framework is used to construct a strictness analysis for attribute grammars. Results of the analysis enable us to transform an attribute grammar such that attributes are evaluated during parsing, if possible. The analysis is proved correct by relating it to a fixpoint...... semantics for attribute grammars. An implementation of the analysis is discussed and some extensions to the analysis are mentioned....

  19. Do host species evolve a specific response to slave-making ants?

    Directory of Open Access Journals (Sweden)

    Delattre Olivier

    2012-12-01

    Full Text Available Abstract Background Social parasitism is an important selective pressure for social insect species. It is particularly the case for the hosts of dulotic (so called slave-making ants, which pillage the brood of host colonies to increase the worker force of their own colony. Such raids can have an important impact on the fitness of the host nest. An arms race which can lead to geographic variation in host defenses is thus expected between hosts and parasites. In this study we tested whether the presence of a social parasite (the dulotic ant Myrmoxenus ravouxi within an ant community correlated with a specific behavioral defense strategy of local host or non-host populations of Temnothorax ants. Social recognition often leads to more or less pronounced agonistic interactions between non-nestmates ants. Here, we monitored agonistic behaviors to assess whether ants discriminate social parasites from other ants. It is now well-known that ants essentially rely on cuticular hydrocarbons to discriminate nestmates from aliens. If host species have evolved a specific recognition mechanism for their parasite, we hypothesize that the differences in behavioral responses would not be fully explained simply by quantitative dissimilarity in cuticular hydrocarbon profiles, but should also involve a qualitative response due to the detection of particular compounds. We scaled the behavioral results according to the quantitative chemical distance between host and parasite colonies to test this hypothesis. Results Cuticular hydrocarbon profiles were distinct between species, but host species did not show a clearly higher aggression rate towards the parasite than toward non-parasite intruders, unless the degree of response was scaled by the chemical distance between intruders and recipient colonies. By doing so, we show that workers of the host and of a non-host species in the parasitized site displayed more agonistic behaviors (bites and ejections towards parasite

  20. Do host species evolve a specific response to slave-making ants?

    Science.gov (United States)

    2012-01-01

    Background Social parasitism is an important selective pressure for social insect species. It is particularly the case for the hosts of dulotic (so called slave-making) ants, which pillage the brood of host colonies to increase the worker force of their own colony. Such raids can have an important impact on the fitness of the host nest. An arms race which can lead to geographic variation in host defenses is thus expected between hosts and parasites. In this study we tested whether the presence of a social parasite (the dulotic ant Myrmoxenus ravouxi) within an ant community correlated with a specific behavioral defense strategy of local host or non-host populations of Temnothorax ants. Social recognition often leads to more or less pronounced agonistic interactions between non-nestmates ants. Here, we monitored agonistic behaviors to assess whether ants discriminate social parasites from other ants. It is now well-known that ants essentially rely on cuticular hydrocarbons to discriminate nestmates from aliens. If host species have evolved a specific recognition mechanism for their parasite, we hypothesize that the differences in behavioral responses would not be fully explained simply by quantitative dissimilarity in cuticular hydrocarbon profiles, but should also involve a qualitative response due to the detection of particular compounds. We scaled the behavioral results according to the quantitative chemical distance between host and parasite colonies to test this hypothesis. Results Cuticular hydrocarbon profiles were distinct between species, but host species did not show a clearly higher aggression rate towards the parasite than toward non-parasite intruders, unless the degree of response was scaled by the chemical distance between intruders and recipient colonies. By doing so, we show that workers of the host and of a non-host species in the parasitized site displayed more agonistic behaviors (bites and ejections) towards parasite than toward non

  1. Malagasy bats shelter a considerable genetic diversity of pathogenic Leptospira suggesting notable host-specificity patterns.

    Science.gov (United States)

    Gomard, Yann; Dietrich, Muriel; Wieseke, Nicolas; Ramasindrazana, Beza; Lagadec, Erwan; Goodman, Steven M; Dellagi, Koussay; Tortosa, Pablo

    2016-04-01

    Pathogenic Leptospira are the causative agents of leptospirosis, a disease of global concern with major impact in tropical regions. Despite the importance of this zoonosis for human health, the evolutionary and ecological drivers shaping bacterial communities in host reservoirs remain poorly investigated. Here, we describe Leptospira communities hosted by Malagasy bats, composed of mostly endemic species, in order to characterize host-pathogen associations and investigate their evolutionary histories. We screened 947 individual bats (representing 31 species, 18 genera and seven families) for Leptospira infection and subsequently genotyped positive samples using three different bacterial loci. Molecular identification showed that these Leptospira are notably diverse and include several distinct lineages mostly belonging to Leptospira borgpetersenii and L. kirschneri. The exploration of the most probable host-pathogen evolutionary scenarios suggests that bacterial genetic diversity results from a combination of events related to the ecology and the evolutionary history of their hosts. Importantly, based on the data set presented herein, the notable host-specificity we have uncovered, together with a lack of geographical structuration of bacterial genetic diversity, indicates that the Leptospira community at a given site depends on the co-occurring bat species assemblage. The implications of such tight host-specificity on the epidemiology of leptospirosis are discussed. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Human and Animal Isolates of Yersinia enterocolitica Show Significant Serotype-Specific Colonization and Host-Specific Immune Defense Properties

    Science.gov (United States)

    Schaake, Julia; Kronshage, Malte; Uliczka, Frank; Rohde, Manfred; Knuuti, Tobias; Strauch, Eckhard; Fruth, Angelika; Wos-Oxley, Melissa

    2013-01-01

    Yersinia enterocolitica is a human pathogen that is ubiquitous in livestock, especially pigs. The bacteria are able to colonize the intestinal tract of a variety of mammalian hosts, but the severity of induced gut-associated diseases (yersiniosis) differs significantly between hosts. To gain more information about the individual virulence determinants that contribute to colonization and induction of immune responses in different hosts, we analyzed and compared the interactions of different human- and animal-derived isolates of serotypes O:3, O:5,27, O:8, and O:9 with murine, porcine, and human intestinal cells and macrophages. The examined strains exhibited significant serotype-specific cell binding and entry characteristics, but adhesion and uptake into different host cells were not host specific and were independent of the source of the isolate. In contrast, survival and replication within macrophages and the induced proinflammatory response differed between murine, porcine, and human macrophages, suggesting a host-specific immune response. In fact, similar levels of the proinflammatory cytokine macrophage inflammatory protein 2 (MIP-2) were secreted by murine bone marrow-derived macrophages with all tested isolates, but the equivalent interleukin-8 (IL-8) response of porcine bone marrow-derived macrophages was strongly serotype specific and considerably lower in O:3 than in O:8 strains. In addition, all tested Y. enterocolitica strains caused a considerably higher level of secretion of the anti-inflammatory cytokine IL-10 by porcine than by murine macrophages. This could contribute to limiting the severity of the infection (in particular of serotype O:3 strains) in pigs, which are the primary reservoir of Y. enterocolitica strains pathogenic to humans. PMID:23959720

  3. First in Vivo Batrachochytrium dendrobatidis Transcriptomes Reveal Mechanisms of Host Exploitation, Host-Specific Gene Expression, and Expressed Genotype Shifts

    OpenAIRE

    Amy R. Ellison; Graziella V. DiRenzo; Caitlin A. McDonald; Karen R. Lips; Kelly R. Zamudio

    2017-01-01

    For generalist pathogens, host species represent distinct selective environments, providing unique challenges for resource acquisition and defense from host immunity, potentially resulting in host-dependent differences in pathogen fitness. Gene expression modulation should be advantageous, responding optimally to a given host and mitigating the costs of generalism. Batrachochytrium dendrobatidis (Bd), a fungal pathogen of amphibians, shows variability in pathogenicity among isolates, and with...

  4. Host specific glycans are correlated with susceptibility to infection by lagoviruses, but not with their virulence.

    Science.gov (United States)

    Lopes, Ana M; Breiman, Adrien; Lora, Mónica; Le Moullac-Vaidye, Béatrice; Galanina, Oxana; Nyström, Kristina; Marchandeau, Stephane; Le Gall-Reculé, Ghislaine; Strive, Tanja; Neimanis, Aleksija; Bovin, Nicolai V; Ruvoën-Clouet, Nathalie; Esteves, Pedro J; Abrantes, Joana; Le Pendu, Jacques

    2017-11-29

    The rabbit hemorrhagic disease virus (RHDV) and the European brown hare syndrome virus (EBHSV) are two lagoviruses from the family Caliciviridae that cause fatal diseases in two leporid genera, Oryctolagus and Lepus , respectively. In the last few years, several examples of host jumps of lagoviruses among leporids were recorded. In addition, a new pathogenic genotype of RHDV emerged and many non-pathogenic strains of lagoviruses have been described. The molecular mechanisms behind host shifts and the emergence of virulence are unknown. Since RHDV uses glycans of the histo-blood group antigen type as attachment factors to initiate infection, we studied if glycan specificities of the new pathogenic RHDV genotype, non-pathogenic lagoviruses and EBHSV potentially play a role in determining host range and virulence of lagoviruses. We observed binding to A, B or H antigens of the histo-blood group family for all strains known to primarily infect European rabbits ( Oryctolagus cuniculus ), that have recently been classified as GI strains. Yet, we could not explain the emergence of virulence since similar glycan specificities were found between several pathogenic and non-pathogenic strains. By contrast, EBHSV, recently classified as GII.1, bound to terminal β-linked N-acetylglucosamine residues of O-glycans. Expression of these attachment factors in the upper respiratory and digestive tracts in three lagomorph species ( Oryctolagus cuniculus, Lepus europaeus and Sylvilagus floridanus ) showed species-specific patterns regarding the susceptibility to infection by these viruses, indicating that species-specific glycan expression is likely a major contributor to lagoviruses host specificity and range. IMPORTANCE Lagoviruses constitute a genus of the Caliciviridae family, comprising highly pathogenic viruses, RHDV and EBHSV, which infect rabbits and hares, respectively. Recently, non-pathogenic strains were discovered and new pathogenic strains have emerged. In addition, host

  5. Consistency in the host specificity and host sensitivity of the Bacteroides HF183 marker for sewage pollution tracking.

    Science.gov (United States)

    Ahmed, W; Masters, N; Toze, S

    2012-10-01

    The host specificity (H-SPF) and host sensitivity (H-SNV) values of the sewage-associated HF183 Bacteroides marker in the current study were compared with the previously published studies in South East Queensland (SEQ), Australia, by testing a large number of wastewater and faecal DNA samples (n=293) from 11 target and nontarget host groups. This was carried out to obtain information on the consistency in the H-SPF and H-SNV values of the HF183 marker for sewage pollution tracking in SEQ. Polymerase chain reaction (PCR) analysis was used to determine the presence/absence of the HF183 marker in wastewater and faecal DNA samples. Among the human composite wastewater (n=59) from sewage treatment plants and individual human (n=20) faecal DNA samples tested, 75 (95%) were PCR positive for the HF183 marker. The overall H-SNV of this marker in target host group was 0·95 (maximum of 1·00). Among the 214 nontarget animal faecal DNA samples tested, 201 (94%) samples were negative for the HF183 marker. Six chicken, five dog and two bird faecal DNA samples, however, were positive for the marker. The overall H-SPF of the HF183 marker to differentiate between target and nontarget faecal DNA samples was 0·94 (maximum of 1·00). The H-SNV (0·95) and H-SPF (0·94) values obtained in this study was slightly lower than previous studies (H-SNV value of 1·00 in 2007 and 1·00 in 2009; H-SPF value of 1·00 in 2007 and 0·99 in 2009). Nonetheless, the overall high H-SNV (0·98) and H-SPF (0·97) values of the HF183 marker over the past 4 years (i.e. 2007-2011) suggest that the HF183 marker can be reliably used for the detection of sewage pollution in environmental waters in SEQ. In the current study, the HF183 marker was detected in small number nontarget animal faecal samples. Care should be taken to interpret results obtained from catchments or waterways that might be potentially contaminated with dog faecal matter or poultry litter. © 2012 The Authors. Letters in Applied

  6. Evolution of life cycle, colony morphology, and host specificity in the family Hydractiniidae (Hydrozoa, Cnidaria).

    Science.gov (United States)

    Miglietta, Maria Pia; Cunningham, Clifford W

    2012-12-01

    Biased transitions are common throughout the tree of life. The class hydrozoa is no exception, having lost the feeding medusa stage at least 70 times. The family hydractiniidae includes one lineage with pelagic medusae (Podocoryna) and several without (e.g., Hydractinia). The benthic colony stage also varies widely in host specificity and in colony form. The five-gene phylogeny presented here requires multiple transitions between character states for medusae, host specificity, and colony phenotype. Significant phylogenetic correlations exist between medusoid form, colony morphology, and host specificity. Species with nonfeeding medusae are usually specialized on a single host type, and reticulate colonies are correlated with nonmotile hosts. The history of feeding medusae is less certain. Podocoryna is nested within five lineages lacking medusae. This requires either repeated losses of medusae, or the remarkable re-evolution of a feeding medusa after at least 150 million years. Traditional ancestral reconstruction favors medusa regain, but a likelihood framework testing biased transitions cannot distinguish between multiple losses versus regain. A hypothesis of multiple losses of feeding medusae requires transient selection pressure favoring such a loss. Populations of species with feeding medusae are always locally rare and lack of feeding medusae does not result in restricted species distribution around the world. © 2012 The Author(s). Evolution© 2012 The Society for the Study of Evolution.

  7. Deciphering bartonella diversity, recombination, and host specificity in a rodent community.

    Directory of Open Access Journals (Sweden)

    Jean-Philippe Buffet

    Full Text Available Host-specificity is an intrinsic feature of many bacterial pathogens, resulting from a long history of co-adaptation between bacteria and their hosts. Alpha-proteobacteria belonging to the genus Bartonella infect the erythrocytes of a wide range of mammal orders, including rodents. In this study, we performed genetic analysis of Bartonella colonizing a rodent community dominated by bank voles (Myodes glareolus and wood mice (Apodemus sylvaticus in a French suburban forest to evaluate their diversity, their capacity to recombine and their level of host specificity. Following the analysis of 550 rodents, we detected 63 distinct genotypes related to B. taylorii, B. grahamii, B. doshiae and a new B. rochalimae-like species. Investigating the most highly represented species, we showed that B. taylorii strain diversity was markedly higher than that of B. grahamii, suggesting a possible severe bottleneck for the latter species. The majority of recovered genotypes presented a strong association with either bank voles or wood mice, with the exception of three B. taylorii genotypes which had a broader host range. Despite the physical barriers created by host specificity, we observed lateral gene transfer between Bartonella genotypes associated with wood mice and Bartonella adapted to bank voles, suggesting that those genotypes might co-habit during their life cycle.

  8. Host specific differences alter the requirement for certain Salmonella genes during swine colonization.

    Science.gov (United States)

    Bearson, Bradley L; Bearson, Shawn M D

    2011-06-02

    The pathogenic potential of Salmonella is determined during the complex interaction between pathogen and host, requiring optimal regulation of multiple bacterial genetic systems within variable in vivo environments. The mouse model of systemic disease has been an extremely productive model to investigate the pathogenesis of Salmonella enterica serovar Typhimurium (S. Typhimurium). Although the mouse model is a widely used paradigm for studying the pathogenesis of systemic disease caused by Salmonella, investigations concerning food safety interventions should employ natural hosts to examine gastrointestinal colonization by Salmonella. Recent research has demonstrated specific differences in the attenuation of certain S. Typhimurium mutants in mice compared to swine. This variation in pathogenesis between the mouse model and pigs for the S. Typhimurium mutants is presumably dependent upon either the requirements for specific gene products during systemic disease (mouse) versus gastrointestinal colonization (pig) or host specific differences. In addition, host specific diversity in Salmonella colonization of swine has also been described in comparison to other food-producing animals, including cattle and chickens. Differences in Salmonella colonization and pathogenesis across diverse animal species highlight the importance of species-specific studies of gastrointestinal colonization for the development of Salmonella interventions to enhance pork safety. Copyright © 2011 Elsevier B.V. All rights reserved.

  9. Evolution of codon usage in Zika virus genomes is host and vector specific

    Science.gov (United States)

    Butt, Azeem Mehmood; Nasrullah, Izza; Qamar, Raheel; Tong, Yigang

    2016-01-01

    The codon usage patterns of viruses reflect the evolutionary changes that allow them to optimize their survival and adapt their fitness to the external environment and, most importantly, their hosts. Here we report the genotype-specific codon usage patterns of Zika virus (ZIKV) strains from the current and previous outbreaks. Several genotype-specific and common codon usage traits were noted in the ZIKV coding sequences, indicating their independent evolutionary origins from a common ancestor. The overall influence of natural selection was more profound than that of mutation pressure, acting on a specific set of viral genes in the Asian-genotype ZIKV strains from the recent outbreak. An interplay between codon adaptation and deoptimization may have allowed the virus to adapt to multiple host and vectors and is reported for the first time in ZIKV genomes. Combining our codon analysis with geographical data on Aedes populations in the Americas suggested that ZIKV has evolved host- and vector-specific codon usage patterns to maintain successful replication and transmission chains within multiple hosts and vectors. PMID:27729643

  10. Aquatic Plant Control Research Program: Host Specificity of Microbial Flora from Eurasian Watermilfoil

    Science.gov (United States)

    1990-06-01

    Test. Table 6 Fraction of Replicates in Which Endophytic GFU Were Detected in Plant Species Fraction of Replicates Having- Endophytic CFU* Plant...which endophytic GFU were detected at end of host- specificity experiments/total number of replicates examined. 0I 0 0 ~ o ’ 0 4 - 0 -4 u~~- z Uc - -4

  11. Suppression of graft-versus-host reactivity by a single host-specific blood transfusion to prospective donors of hemopoietic cells

    NARCIS (Netherlands)

    Knulst, A.C.; Bril-Bazuin, C.; Savelkoul, H.F.J.; Benner, R.

    1991-01-01

    Delayed-type hypersensitivity responses against recipient's histocompatibility antigens can occur early in the course of a graft-versus-host reaction in lethally irradiated allogeneically reconstituted mice. This reactivity could be suppressed by a single host-specific blood transfusion to the

  12. Toxoplasma gondii infection specifically increases the levels of key host microRNAs.

    Directory of Open Access Journals (Sweden)

    Gusti M Zeiner

    2010-01-01

    Full Text Available The apicomplexan parasite Toxoplasma gondii can infect and replicate in virtually any nucleated cell in many species of warm-blooded animals; thus, it has evolved the ability to exploit well-conserved biological processes common to its diverse hosts. Here we have investigated whether Toxoplasma modulates the levels of host microRNAs (miRNAs during infection.Using microarray profiling and a combination of conventional molecular approaches we report that Toxoplasma specifically modulates the expression of important host microRNAs during infection. We show that both the primary transcripts for miR-17 approximately 92 and miR-106b approximately 25 and the pivotal miRNAs that are derived from miR-17 approximately 92 display increased abundance in Toxoplasma-infected primary human cells; a Toxoplasma-dependent up-regulation of the miR-17 approximately 92 promoter is at least partly responsible for this increase. The abundance of mature miR-17 family members, which are derived from these two miRNA clusters, remains unchanged in host cells infected with the closely related apicomplexan Neospora caninum; thus, the Toxoplasma-induced increase in their abundance is a highly directed process rather than a general host response to infection.Altered levels of miR-17 approximately 92 and miR-106b approximately 25 are known to play crucial roles in mammalian cell regulation and have been implicated in numerous hyperproliferative diseases although the mechanisms driving their altered expression are unknown. Hence, in addition to the implications of these findings on the host-pathogen interaction, Toxoplasma may represent a powerful probe for understanding the normal mechanisms that regulate the levels of key host miRNAs.

  13. Site-specific programming of the host epithelial transcriptome by the gut microbiota

    DEFF Research Database (Denmark)

    Sommer, Felix; Nookaew, Intawat; Sommer, Nina

    2015-01-01

    BACKGROUND: The intestinal epithelium separates us from the microbiota but also interacts with it and thus affects host immune status and physiology. Previous studies investigated microbiota-induced responses in the gut using intact tissues or unfractionated epithelial cells, thereby limiting....... The microbial impact on host gene expression was highly site specific, as epithelial responses to the microbiota differed between cell fractions. Specific transcriptional regulators were enriched in each fraction. In general, the gut microbiota induced a more rapid response in the colon than in the ileum...... conclusions about regional differences in the epithelium. Here, we sought to investigate microbiota-induced transcriptional responses in specific fractions of intestinal epithelial cells. To this end, we used microarray analysis of laser capture microdissection (LCM)-harvested ileal and colonic tip and crypt...

  14. Host-Specific and Segment-Specific Evolutionary Dynamics of Avian and Human Influenza A Viruses: A Systematic Review.

    Science.gov (United States)

    Kim, Kiyeon; Omori, Ryosuke; Ueno, Keisuke; Iida, Sayaka; Ito, Kimihito

    2016-01-01

    Understanding the evolutionary dynamics of influenza viruses is essential to control both avian and human influenza. Here, we analyze host-specific and segment-specific Tajima's D trends of influenza A virus through a systematic review using viral sequences registered in the National Center for Biotechnology Information. To avoid bias from viral population subdivision, viral sequences were stratified according to their sampling locations and sampling years. As a result, we obtained a total of 580 datasets each of which consists of nucleotide sequences of influenza A viruses isolated from a single population of hosts at a single sampling site within a single year. By analyzing nucleotide sequences in the datasets, we found that Tajima's D values of viral sequences were different depending on hosts and gene segments. Tajima's D values of viruses isolated from chicken and human samples showed negative, suggesting purifying selection or a rapid population growth of the viruses. The negative Tajima's D values in rapidly growing viral population were also observed in computer simulations. Tajima's D values of PB2, PB1, PA, NP, and M genes of the viruses circulating in wild mallards were close to zero, suggesting that these genes have undergone neutral selection in constant-sized population. On the other hand, Tajima's D values of HA and NA genes of these viruses were positive, indicating HA and NA have undergone balancing selection in wild mallards. Taken together, these results indicated the existence of unknown factors that maintain viral subtypes in wild mallards.

  15. Are cryptic host species also cryptic to parasites? Host specificity and geographical distribution of acanthocephalan parasites infecting freshwater Gammarus.

    Science.gov (United States)

    Westram, A M; Baumgartner, C; Keller, I; Jokela, J

    2011-07-01

    Many parasites infect multiple host species. In coevolving host-parasite interactions, theory predicts that parasites should be adapted to locally common hosts, which could lead to regional shifts in host preferences. We studied the interaction between freshwater Gammarus (Crustacea, Amphipoda) and their acanthocephalan parasites using a large-scale field survey and experiments, combined with molecular identification of cryptic host and parasite species. Gammarus pulex is a common host for multiple species of Acanthocephala in Europe but, in Switzerland, is less common than two cryptic members of the Gammarus fossarum species complex (type A and type B). We found that natural populations of these cryptic species were frequently infected by Pomphorhynchus tereticollis and Polymorphus minutus. Four additional parasite species occurred only locally. Parasites were more common in G. fossarum type B than in type A. Infection experiments using several host and parasite sources confirmed consistently lower infection rates in G. pulex than in G. fossarum type A, suggesting a general difference in susceptibility between the two species. In conclusion, we could show that cryptic host species differ in their interactions with parasites, but that these differences were much less dramatic than differences between G. fossarum (type A) and G. pulex. Our data suggest that the acanthocephalans in Switzerland have adapted to the two most common Gammarus species in this region where host species frequencies differ from near-by regions in Europe. Copyright © 2011 Elsevier B.V. All rights reserved.

  16. Mesophotic coral depth acclimatization is a function of host-specific symbiont physiology

    KAUST Repository

    Ziegler, Maren

    2015-02-06

    Mesophotic coral ecosystems receive increasing attention owing to their potential as deep coral refuges in times of global environmental change. Here, the mechanisms of coral holobiont photoacclimatization over a 60 m depth gradient in the central Red Sea were examined for the four coral genera Porites, Leptoseris, Pachyseris, and Podabacia. General acclimatization strategies were common to all host-symbiont combinations, e.g., Symbiodinium cell densities and photoprotective (PP) to light-harvesting pigment ratios both significantly decreased with water depth. Porites harbored Symbiodinium type C15 over the whole 60 m depth range, while Pachyseris and Podabacia had limited vertical distributions and hosted mainly Symbiodinium type C1. Symbiodinium type C15 had generally higher xanthophyll de-epoxidation rates and lower maximum quantum yields than C1, and also exhibited a strong photoacclimatory signal over depth that relates to the large distribution range of Porites. Interestingly, the coral host had an effect on Symbiodinium pigment composition. When comparing Symbiodinium type C1 in Podabacia and Pachyseris, the ß-carotene chl a−1, the peridinin chl a−1, and diadinoxanthin chl a−1 ratios were significantly different between host species. Our data support a view that depth acclimatization of corals in the mesophotics is facilitated by Symbiodinium physiology, which in turn is host-specific.

  17. Strategy and Aspects of Monitoring / Control Strictly in Coordinated Subsystems

    Directory of Open Access Journals (Sweden)

    William José Borges

    2012-06-01

    Full Text Available This paper aims to discuss the approach structures of the strictly coordinated theoretical framework developed by Zylbersztajn and Farina (1999 as an expanded perspective of the firm, taking into account the food supply chains as an extension of the nexus of contracts proposed by Coase (1937 and taken up by Williamson (1985. The structures stand out as strictly coordinated. Zylbersztajn and Farina (1999 turn to identifying points of common interests that encourage firms to promote contracts between themselves in a strictly coordinated way, considering the degree of asset specificity involved in the transaction and the competitive forces that determine the search for strategic positioning organizations to achieve sustainable superior results.

  18. Host specificity and growth of kelp gametophytes symbiotic with filamentous red algae (Ceramiales, Rhodophyta)

    Science.gov (United States)

    Hubbard, Charlene B.; Garbary, David J.; Kim, Kwang Young; Chiasson, David M.

    2004-02-01

    Kelp gametophytes were previously observed in nature living endophytically in red algal cell walls. Here we examine the interactions of two kelp species and six red algae in culture. Gametophytes of Nereocystis luetkeana (Mertens) Postels et Ruprecht became endophytic in the cell walls of Griffithsia pacifica Kylin and Antithamnion defectum Kylin, and grew epiphytically in high abundance on G. japonica Okamura and Aglaothamnion oosumiense Itono. Alaria esculenta (Linnaeus) Greville from the Atlantic coast of Nova Scotia became endophytic in Aglaothamnion oosumiense, Antithamnion defectum, Callithamnion sp., G. japonica, G. pacifica, and Pleonosporium abysicola Gardner, all from the Pacific Ocean. Some cultures were treated with phloroglucinol before infection to thicken the cell walls. The endophytic gametophytes were smaller and grew more slowly than gametophytes epiphytic on the same host. N. luetkeana failed to become endophytic in some of the potential hosts, and this may reflect host specificity, or culture artifacts. This work improves our understanding of the process of infection of red algae by kelp gametophytes, and broadens our knowledge of host specificity in endophytic symbioses.

  19. Patterns of Abundance and Host Specificity of Bat Ectoparasites in the Central Balkans.

    Science.gov (United States)

    Burazerovic, J; Orlova, M; Obradovic, M; Cirovic, D; Tomanovic, S

    2018-01-10

    Bats are hosts to a number of ectoparasites-acarines (ticks, chiggers, other mites), bat flies, and fleas. Bat ectoparasites might have significant ecological and public health importance as they may be potential vectors of zoonotic agents. It is important to identify their distribution, diversity, and host-parasite associations. Bat ectoparasites in the central Balkans have been largely understudied. The present research was conducted in 45 localities at the territory of Bosnia and Herzegovina, former Yugoslav Republic of Macedonia, Montenegro, and Serbia. In total, 1,143 individuals of 18 species of bats have been examined for the presence and abundance of ectoparasite species during 3 yr of research. In total, 21 ectoparasite species have been identified: three species of ticks, seven species of mites (including one species of chigger), eight species of bat flies, and three species of fleas. In total, 80 host-parasite associations have been identified. The largest number of ectoparasites parasitized primarily only one host species. The highest total number of hosts was identified for ectoparasite species Ixodes vespertilionis Koch, Nycteribia schmidlii Schiner, and Spinturnix myoti Kolenati. The spinturnicid mite Spinturnix psi Kolenati was the most abundant ectoparasite species and together with Penicilidia dufouri Westwood the most widely distributed species of bat ectoparasite, being present at 21 localities in the central Balkans. The presented data include the first systematic records of patterns of prevalence, mean intensity, mean abundance, and host specificity for bat ectoparasites in the central Balkans. © The Author(s) 2017. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. An updated concept and revised composition for Hamacreadium Linton, 1910 (Opecoelidae: Plagioporinae) clarifies a previously obscured pattern of host-specificity among species.

    Science.gov (United States)

    Martin, Storm B; Cutmore, Scott C; Ward, Selina; Cribb, Thomas H

    2017-04-12

    The present concept of the trematode genus Hamacreadium Linton, 1910 encompasses considerable morphological variability and includes species reported from a broad range of fishes. These include herbivores and planktivores, despite the life-cycle of the type-species, Hamacreadium mutabile Linton, 1910, being known to use fishes as intermediate hosts. Reports of H. mutabile are numerous, spanning the west Atlantic, east Pacific and Indo-west Pacific, whereas other nominal species are infrequently reported and several inadequately described. Following a comprehensive review, a strict revised morphological definition is proposed for the genus. Several nominal species are excluded, but, conversely, finer distinctions are recognised among the species concluded to genuinely belong in the genus. Justified records for species retained in the genus are overwhelmingly from fishes of the families Lutjanidae Gill (snappers) and Lethrinidae Bonaparte (emperors), revealing a previously concealed pattern of host-specificity. For H. mutabile, it is argued that only records from western Atlantic lutjanid fishes should be considered genuine; those from plausible Indo-Pacific fishes most likely represent different species. In addition to H. mutabile, eight species are recognised: Hamacreadium cribbi Bray & Justine, 2016, Hamacreadium hainanense Shen, 1990, Hamacreadium interruptum Nagaty, 1941, Hamacreadium lethrini Yamaguti, 1934, Hamacreadium longivesiculum (Yamaguti, 1952) n. comb., Hamacreadium lutiani (Shen, 1990) n. comb., Hamacreadium morgani Baz,1946 and Hamacreadium phyllorchis (Bilqees, 1976) Cribb, 2005. A key to species of Hamacreadium and comprehensive lists of all host-locality records are included.

  1. Growing diversity of trypanosomatid parasites of flies (Diptera: Brachycera): Frequent cosmopolitism and moderate host specificity

    Czech Academy of Sciences Publication Activity Database

    Týč, Jiří; Votýpka, Jan; Klepetková, H.; Šuláková, H.; Jirků, Milan; Lukeš, Julius

    2013-01-01

    Roč. 69, č. 1 (2013), s. 255-264 ISSN 1055-7903 R&D Projects: GA ČR GD206/09/H026 Grant - others:GA AV ČR(CZ) M200961204 Institutional support: RVO:60077344 Keywords : Host specificity * Geographic distribution * Diversity * Phylogeny * Trypanosomatida * Leishmania Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 4.018, year: 2013

  2. Evidence of host specificity and congruence between phylogenies of bitterling and freshwater mussels

    Czech Academy of Sciences Publication Activity Database

    Liu, H.-Z.; Zhu, Y.-R.; Smith, C.; Reichard, Martin

    2006-01-01

    Roč. 45, č. 3 (2006), s. 428-434 ISSN 1021-5506 Grant - others:NSFC(CN) 30470237; NSFC(CN) 40432003; Innovation Program of the Chinese Academy of Sciences(CN) KZCX3-SW-126 Institutional research plan: CEZ:AV0Z60930519 Keywords : bitterling * host specificity * coevolution * phylogeny Subject RIV: EG - Zoology Impact factor: 0.943, year: 2006 http://zoolstud.sinica.edu.tw/Journals/45.3/428.pdf

  3. Low host specificity of root-associated fungi at an Arctic site.

    Science.gov (United States)

    Botnen, Synnøve; Vik, Unni; Carlsen, Tor; Eidesen, Pernille B; Davey, Marie L; Kauserud, Håvard

    2014-02-01

    In High Arctic ecosystems, plant growth and reproduction are limited by low soil moisture and nutrient availability, low soil and air temperatures, and a short growing season. Mycorrhizal associations facilitate plant nutrient acquisition and water uptake and may therefore be particularly ecologically important in nutrition-poor and dry environments, such as parts of the Arctic. Similarly, endophytic root associates are thought to play a protective role, increasing plants' stress tolerance, and likely have an important ecosystem function. Despite the importance of these root-associated fungi, little is known about their host specificity in the Arctic. We investigated the host specificity of root-associated fungi in the common, widely distributed arctic plant species Bistorta vivipara, Salix polaris and Dryas octopetala in the High Arctic archipelago Svalbard. High-throughput sequencing of the internal transcribed spacer 1 (ITS1) amplified from whole root systems generated no evidence of host specificity and no spatial autocorrelation within two 3 m × 3 m sample plots. The lack of spatial structure at small spatial scales indicates that Common Mycelial Networks (CMNs) are rare in marginal arctic environments. Moreover, no significant differences in fungal OTU richness were observed across the three plant species, although their root system characteristics (size, biomass) differed considerably. Reasons for lack of host specificity could be that association with generalist fungi may allow arctic plants to more rapidly and easily colonize newly available habitats, and it may be favourable to establish symbiotic relationships with fungi possessing different physiological attributes. © 2013 John Wiley & Sons Ltd.

  4. The phylogenetic study on Thelohanellus species (Myxosporea) in relation to host specificity and infection site tropism.

    Science.gov (United States)

    Shin, Sang Phil; Nguyen, Van Giap; Jeong, Jae Mook; Jun, Jin Woo; Kim, Ji Hyung; Han, Jee Eun; Baeck, Gun Wook; Park, Se Chang

    2014-03-01

    Thelohanellus kitauei (Myxobolidae) infects cyprinid fish. The evolution of species derived from common ancestors results in the sharing of biological features. To reveal the origin of T. kitauei biological features, the correlation between phylogeny and biological features of Myxobolidae was investigated by Bayesian inference tree and Bayesian tip association significance testing. The results demonstrated that host specificity and infection site tropism were correlated with the phylogeny of Myxobolidae, and that the biological features of T. kitauei originated from the ancient Myxobolidae as exhibited by the non-specific infection site tropism and the ability to infect cyprinids. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Prevalence and differential host-specificity of two avian blood parasite genera in the Australo-Papuan region

    Science.gov (United States)

    Beadell, J.S.; Gering, E.; Austin, J.; Dumbacher, J.P.; Peirce, M.A.; Pratt, T.K.; Atkinson, C.T.; Fleischer, R.C.

    2004-01-01

    The degree to which widespread avian blood parasites in the genera Plasmodium and Haemoproteus pose a threat to novel hosts depends in part on the degree to which they are constrained to a particular host or host family. We examined the host distribution and host-specificity of these parasites in birds from two relatively understudied and isolated locations: Australia and Papua New Guinea. Using polymerase chain reaction (PCR), we detected infection in 69 of 105 species, representing 44% of individuals surveyed (n = 428). Across host families, prevalence of Haemoproteus ranged from 13% (Acanthizidae) to 56% (Petroicidae) while prevalence of Plasmodium ranged from 3% (Petroicidae) to 47% (Ptilonorhynchidae). We recovered 78 unique mitochondrial lineages from 155 sequences. Related lineages of Haemoproteus were more likely to derive from the same host family than predicted by chance at shallow (average LogDet genetic distance = 0, n = 12, P = 0.001) and greater depths (average distance = 0.014, n = 11, P parasite phylogeny. Within two major Haemoproteus subclades identified in a maximum likelihood phylogeny, host-specificity was evident up to parasite genetic distances of 0.029 and 0.007 based on logistic regression. We found no significant host relationship among lineages of Plasmodium by any method of analysis. These results support previous evidence of strong host-family specificity in Haemoproteus and suggest that lineages of Plasmodium are more likely to form evolutionarily-stable associations with novel hosts.

  6. Host-Specific and Segment-Specific Evolutionary Dynamics of Avian and Human Influenza A Viruses: A Systematic Review

    KAUST Repository

    Kim, Kiyeon

    2016-01-13

    Understanding the evolutionary dynamics of influenza viruses is essential to control both avian and human influenza. Here, we analyze host-specific and segment-specific Tajima’s D trends of influenza A virus through a systematic review using viral sequences registered in the National Center for Biotechnology Information. To avoid bias from viral population subdivision, viral sequences were stratified according to their sampling locations and sampling years. As a result, we obtained a total of 580 datasets each of which consists of nucleotide sequences of influenza A viruses isolated from a single population of hosts at a single sampling site within a single year. By analyzing nucleotide sequences in the datasets, we found that Tajima’s D values of viral sequences were different depending on hosts and gene segments. Tajima’s D values of viruses isolated from chicken and human samples showed negative, suggesting purifying selection or a rapid population growth of the viruses. The negative Tajima’s D values in rapidly growing viral population were also observed in computer simulations. Tajima’s D values of PB2, PB1, PA, NP, and M genes of the viruses circulating in wild mallards were close to zero, suggesting that these genes have undergone neutral selection in constant-sized population. On the other hand, Tajima’s D values of HA and NA genes of these viruses were positive, indicating HA and NA have undergone balancing selection in wild mallards. Taken together, these results indicated the existence of unknown factors that maintain viral subtypes in wild mallards.

  7. Host specificity and colony impacts of the fire ant pathogen, Solenopsis invicta virus 3.

    Science.gov (United States)

    Porter, Sanford D; Valles, Steven M; Oi, David H

    2013-09-01

    An understanding of host specificity is essential before pathogens can be used as biopesticides or self-sustaining biocontrol agents. In order to define the host range of the recently discovered Solenopsis invicta virus 3 (SINV-3), we exposed laboratory colonies of 19 species of ants in 14 genera and 4 subfamilies to this virus. Despite extreme exposure during these tests, active, replicating infections only occurred in Solenopsis invicta Buren and hybrid (S. invicta×S. richteri) fire ant colonies. The lack of infections in test Solenopsis geminata fire ants from the United States indicates that SINV-3 is restricted to the saevissima complex of South American fire ants, especially since replicating virus was also found in several field-collected samples of the black imported fire ant, Solenopsis richteri Forel. S. invicta colonies infected with SINV-3 declined dramatically with average brood reductions of 85% or more while colonies of other species exposed to virus remained uninfected and healthy. The combination of high virulence and high host specificity suggest that SINV-3 has the potential for use as either a biopesticide or a self-sustaining biocontrol agent. Published by Elsevier Inc.

  8. A Codon-Based Model of Host-Specific Selection in Parasites, with an Application to the Influenza A Virus

    DEFF Research Database (Denmark)

    Forsberg, Ronald; Christiansen, Freddy Bugge

    2003-01-01

    Parasites sometimes expand their host range by acquiring a new host species. Following a host change event, the selective regime acting on a given parasite gene may change due to host-specific adaptive alterations of protein functionality or host-specific immune-mediated selection. We present...... a codon-based model that attempts to include these effects by allowing the position-specific substitution process to change in conjunction with a host change event. Following maximum-likelihood parameter estimation, we employ an empirical Bayesian procedure to identify candidate sites, potentially...... involved in hostspecific adaptation. We discuss the applicability of the model to the more general problem of ascertaining whether the selective regime differs between two groups of related organisms. The utility of the model is illustrated on a dataset of nucleoprotein sequences from the influenza A virus...

  9. The gills of reef fish support a distinct microbiome influenced by host-specific factors.

    Science.gov (United States)

    Pratte, Zoe A; Besson, Marc; Hollman, Rebecca D; Stewart, Frank J

    2018-02-16

    Teleost fish represent the most diverse of the vertebrate groups and play important roles in food webs, as ecosystem engineers, and as vectors for microorganisms. However, the microbial ecology of fishes remains underexplored for most host taxa, and for certain niches on the fish body. This is particularly true for the gills, the key sites for respiration and waste exchange in fishes. Here, we provide a comprehensive analysis of the gill microbiome. We focus on ecologically diverse taxa from coral reefs around Moorea, sampling the gill and intestines of adults and juveniles representing 15 families. Gill microbiome composition differed significantly from that of the gut in both adults and juveniles, with fish-associated niches having lower alpha diversity and higher beta diversity compared to seawater, sediment, and algae-associated microbiomes. Of ∼45,000 operational taxonomic units (OTUs) detected across all samples, 11% and 13% were detected only in the gill and intestine, respectively. OTUs most enriched in the gill included members of the gammaproteobacterial genus Shewanella and family Endozoicimonaceae. In adult fish, both gill and intestinal microbiomes varied significantly among host species grouped by diet category. Gill and intestinal microbiomes from the same individual were more similar to one another compared to gill and intestinal microbiomes from different individuals. These results demonstrate that distinct body sites are jointly influenced by host-specific organizing factors operating at the level of the host individual. The results also identify taxonomic signatures unique to the gill and intestine, confirming fish-associated niches as distinct reservoirs of marine microbial diversity. Importance Fish breath and excrete waste through their gills. The gills are also potential sites of pathogen invasion and colonization by other microbes. However, we know little about the microbial communities that live on the gill and the factors shaping their

  10. Host specificity and reproductive success of yucca moths (Tegeticula spp. Lepidoptera: Prodoxidae) mirror patterns of gene flow between host plant varieties of the Joshua tree (Yucca brevifolia: Agavaceae).

    Science.gov (United States)

    Smith, Christopher Irwin; Drummond, Christopher S; Godsoe, William; Yoder, Jeremy B; Pellmyr, Olle

    2009-12-01

    Coevolution between flowering plants and their pollinators is thought to have generated much of the diversity of life on Earth, but the population processes that may have produced these macroevolutionary patterns remain unclear. Mathematical models of coevolution in obligate pollination mutualisms suggest that phenotype matching between plants and their pollinators can generate reproductive isolation. Here, we test this hypothesis using a natural experiment that examines the role of natural selection on phenotype matching between yuccas and yucca moths (Tegeticula spp.) in mediating reproductive isolation between two varieties of Joshua tree (Yucca brevifolia var. brevifolia and Y. brevifolia var. jaegeriana). Using passive monitoring techniques, DNA barcoding, microsatellite DNA genotyping, and sibship reconstruction, we track host specificity and the fitness consequences of host choice in a zone of sympatry. We show that the two moth species differ in their degree of host specificity and that oviposition on a foreign host plant results in the production of fewer offspring. This difference in host specificity between the two moth species mirrors patterns of chloroplast introgression from west to east between host varieties, suggesting that natural selection acting on pollinator phenotypes mediates gene flow and reproductive isolation between Joshua-tree varieties.

  11. A host-inducible cytochrome P-450 from a host-specific caterpillar: molecular cloning and evolution.

    Science.gov (United States)

    Cohen, M B; Schuler, M A; Berenbaum, M R

    1992-11-15

    Cytochrome P-450 monooxygenases (P-450s) play a critical role in the detoxification of natural and synthetic toxins in a wide range of organisms. We have isolated and sequenced cDNA clones encoding a P-450, CYP6B1, from larvae of Papilio polyxenes (Lepidoptera: Papilionidae), the black swallowtail butterfly. This P-450, cloned from a herbivorous insect, is highly inducible by xanthotoxin, a secondary metabolite abundant in the host plants of this specialized herbivore. On Northern blots, mRNAs crossreactive with CYP6B1 were detected in three Papilio species that, like the black swallowtail, have high levels of xanthotoxin-metabolic P-450 activity and encounter xanthotoxin or related compounds in their host plants; in contrast, no crossreactive mRNAs were detectable in three papilinid species that never encounter xanthotoxin in their host plants and lack detectable xanthotoxin-metabolic activity. These results provide evidence that new P-450s can arise as herbivores colonize different host plants and support the hypothesis that interactions between herbivores and their toxin-producing host plants have contributed to the diversification of the P-450 superfamily.

  12. A host-inducible cytochrome P-450 from a host-specific caterpillar: molecular cloning and evolution.

    Science.gov (United States)

    Cohen, M B; Schuler, M A; Berenbaum, M R

    1992-01-01

    Cytochrome P-450 monooxygenases (P-450s) play a critical role in the detoxification of natural and synthetic toxins in a wide range of organisms. We have isolated and sequenced cDNA clones encoding a P-450, CYP6B1, from larvae of Papilio polyxenes (Lepidoptera: Papilionidae), the black swallowtail butterfly. This P-450, cloned from a herbivorous insect, is highly inducible by xanthotoxin, a secondary metabolite abundant in the host plants of this specialized herbivore. On Northern blots, mRNAs crossreactive with CYP6B1 were detected in three Papilio species that, like the black swallowtail, have high levels of xanthotoxin-metabolic P-450 activity and encounter xanthotoxin or related compounds in their host plants; in contrast, no crossreactive mRNAs were detectable in three papilinid species that never encounter xanthotoxin in their host plants and lack detectable xanthotoxin-metabolic activity. These results provide evidence that new P-450s can arise as herbivores colonize different host plants and support the hypothesis that interactions between herbivores and their toxin-producing host plants have contributed to the diversification of the P-450 superfamily. Images PMID:1279697

  13. Redundancy, resilience and host specificity of the ruminal microbiota: Implications for engineering improved ruminal fermentations

    Directory of Open Access Journals (Sweden)

    Paul James Weimer

    2015-04-01

    Full Text Available The ruminal microbial community is remarkably diverse, containing hundreds of different bacterial and archaeal species, plus many species of fungi and protozoa. Molecular studies have identified a core microbiome dominated by phyla Firmicutes and Bacteroidetes, but also containing many other taxa. The rumen provides an ideal laboratory for studies on microbial ecology and the demonstration of ecological principles. In particular, the microbial community demonstrates both redundancy (overlap of function among multiple species and resilience (resistance to, and capacity to recover from, perturbation. These twin properties provide remarkable stability that maintains digestive function for the host across a range of feeding and management conditions, but they also provide a challenge to engineering the rumen for improved function (e.g., improved fiber utilization or decreased methane production. Direct ruminal dosing or feeding of probiotic strains often fails to establish the added strains, due to intensive competition and amensalism from the indigenous residents that are well-adapted to the historical conditions within each rumen. Known exceptions include introduced strains that can fill otherwise unoccupied niches, as in the case of specialist bacteria that degrade phytotoxins such as mimosine or fluoroacetate. An additional complicating factor in manipulating the ruminal fermentation is the individuality or host specificity of the microbiota, in which individual animals contain a particular community whose species composition is capable of reconstituting itself, even following a near-total exchange of ruminal contents from another herd mate maintained on the same diet. Elucidation of the interactions between the microbial community and the individual host that establish and maintain this specificity may provide insights into why individual hosts vary in production metrics (e.g., feed efficiency or milk fat synthesis, and how to improve herd

  14. Enemy-free space and habitat-specific host specialization in a butterfly.

    Science.gov (United States)

    Wiklund, Christer; Friberg, Magne

    2008-08-01

    The majority of herbivorous insects have relatively specialized food habits. This suggests that specialization has some advantage(s) over generalization. Traditionally, feeding specialization has been thought to be linked to digestive or other food-related physiological advantages, but recent theory suggests that generalist natural enemies of herbivorous insects can also provide a major selective pressure for restricted host plant range. The European swallowtail butterfly Papilio machaon utilizes various plants in the Apiaceae family as hosts, but is an ecological specialist being monophagous on Angelica archangelica in southern Sweden. This perennial monocarp grows in three seaside habitat types: (1) on the barren rocky shore in the absence of any surrounding vegetation, (2) on the rocky shore with some surrounding vegetation, and (3) on species-rich meadows. The rocky shore habitat harbors few invertebrate generalist predators, whereas a number of invertebrate predators abound in the meadowland habitat. Here, we test the importance of enemy-free space for feeding specialization in Papilio machaon by assessing survival of larvae placed by hand on A. archangelica in each of the three habitat types, and by assessing the habitat-specificity of adult female egg-laying behavior by recording the distribution of eggs laid by free-flying adult females among the three habitat types. Larval survival was substantially higher in the rocky shore habitat than in the meadowland and significantly higher on host plants without surrounding vegetation on the rocky shore. Eggs laid by free-flying females were found in all three habitat types, but were significantly more frequent in the rocky shore habitat, suggesting that females prefer to lay eggs in the habitat type where offspring survival is highest. These results show that larval survivorship on the same host plant species can be strongly habitat-specific, and suggest that enemy-free space is an underlying factor that drives

  15. Genetic diversity, temporal dynamics, and host specificity in blood parasites of passerines in north China.

    Science.gov (United States)

    Huang, Xi; Dong, Lu; Zhang, Chenglin; Zhang, Yanyun

    2015-12-01

    Avian blood parasites have been preliminarily studied in East Asia, but no data are available from long-term monitoring. The aim of this study was to evaluate the prevalence, genetic diversity, and temporal dynamics of Plasmodium, Haemoproteus, and Leucocytozoon in two passerine communities (one forest and one urban) in north China from 2008 to 2013, as well as the association between infected lineages and host specificities. Out of 633 birds from 40 species, 157 individuals (24.8 %) were infected; overall prevalence was 26.7 % and 16.8 % in two sites, respectively. The dominant avian blood parasite genus in the forest park changed yearly between Plasmodium and Haemoproteus, while the Leucocytozoon maintained a low infection level. Forty-four haplotypes were identified by sequencing a 432-bp fragment of the cytochrome b (cyt b) gene; more than 70 % were novel (six Plasmodium lineages, 16 Haemoproteus lineages, and nine Leucocytozoon lineages). Based on our data gathered over consecutive years, we found that the highly observed lineages of Haemoproteus showed higher host diversities than those of Plasmodium, and the most infected lineage EMEL01 (100 % identity with SGS1) take on the highest host diversity but low temporal diversity of the two genera, implying that this lineage infected a great diversity of species in certain years, but maintained a lower infection level or even disappeared in other years. The results suggest that genetic diversity of avian blood parasites in East Asia is high and provides scope for further research. In addition, compared with overall analysis, yearly prevalence monitoring is important in uncovering the temporal dynamic and host specificity variations over time.

  16. Soilborne fungi have host affinity and host-specific effects on seed germination and survival in a lowland tropical forest

    Science.gov (United States)

    The Janzen-Connell (JC) hypothesis provides a powerful framework for explaining the maintenance of tree diversity in tropical forests. Its central tenet -- that recruits experience high mortality near conspecifics and at high densities -- assumes a degree of host specialization in interactions betwe...

  17. Host Range Specificity of Scymnus camptodromus (Coleoptera: Coccinellidae), A Predator of Hemlock Woolly Adelgid (Hemiptera: Adelgidae).

    Science.gov (United States)

    Limbu, Samita; Cassidy, Katie; Keena, Melody; Tobin, Patrick; Hoover, Kelli

    2016-02-01

    Scymnus (Neopullus) camptodromus Yu and Liu (Coleoptera: Coccinellidae) was brought to the United States from China as a potential biological control agent for hemlock woolly adelgid (Adelges tsugae Annand) (Hemiptera: Adelgidae). Scymnus camptodromus phenology is closely synchronized with that of A. tsugae and has several characteristics of a promising biological control agent. As a prerequisite to field release, S. camptodromus was evaluated for potential nontarget impacts. In host range studies, the predator was given the choice of sympatric adelgid and nonadelgid prey items. Nontarget testing showed that S. camptodromus will feed to some degree on other adelgid species, but highly prefers A. tsugae. We also evaluated larval development of S. camptodromus on pine bark adelgid (Pineus strobi (Hartig)) (Hemiptera: Adelgidae) and larch adelgid (Adelges laricis Vallot) (Hemiptera: Adelgidae); a small proportion of predator larvae was able to develop to adulthood on P. strobi or A. laricis alone. Scymnus camptodromus showed no interest in feeding on woolly alder aphid (Paraprociphilus tessellatus Fitch) (Hemiptera: Aphididae) or woolly apple aphid (Eriosoma lanigerum (Hausmann)) (Hemiptera: Aphididae), and minimal interest in cotton aphid (Aphis gossypii Glover) (Hemiptera: Aphididae) in choice and no-choice experiments. Scymnus camptodromus females did not oviposit on any host material other than A. tsugae-infested hemlock. Under the circumstances of the study, S. camptodromus appears to be a specific predator of A. tsugae, with minimal risk to nontarget species. Although the predator can develop on P. strobi, the likelihood that S. camptodromus would oviposit on pine hosts of this adelgid is small.

  18. Molecular phylogeny of the mycorrhizal desert truffles (Terfezia and Tirmania), host specificity and edaphic tolerance.

    Science.gov (United States)

    Díez, Jesús; Manjón, José Luis; Martin, Francis

    2002-01-01

    Terfezia and Tirmania, so called desert truffles, are mycorrhizal fungi mostly endemic to arid and semi-arid areas of the Mediterranean Region, where they are associated with Helianthemum species. The aim of this work was to study the phylogenetic relationships in these pezizalean hypogeous fungi. The restriction fragment length polymorphism (RFLP) and DNA sequences of internal transcribed spacers (ITS) of the nuclear rDNA were studied for several morphological species, Terfezia arenaria, T. boudieri, T. claveryi, T. leptoderma, T. terfezioides (=Mattirolomyces terfezioides), Tirmania nivea and T. pinoyi. The sequences were analyzed with distance and parsimony methods. Phylogenetic analyses indicated a close genetic relationship between Tirmania and Terfezia. They may have arisen from a single evolutionary lineage of pezizalean fungi that developed the hypogeous habit as an adaptation to heat and drought in Mediterranean ecosystems. This analysis also supports the re-establishment of the genus Mattirolomyces. The genera Tirmania and Terfezia were monophyletic, and morphological species corresponded to phylogenetic species. The Tirmania clade comprises desert truffles with smooth spores and amyloid asci, which were found in deserts. The Terfezia clade grouped species found in semi-arid habitats having ornamented and spherical spores. These species are adapted to exploit different types of soil (either acid or basic soils) in association with specific hosts (either basophilous or acidophilous species). Although other factors might also play a role, host specialization and edaphic tolerances (fungus and/or host tolerances) might be the key in the species diversity of these genera.

  19. Host Specificity in the Honeybee Parasitic Mite, Varroa spp. in Apis mellifera and Apis cerana.

    Directory of Open Access Journals (Sweden)

    Alexis L Beaurepaire

    Full Text Available The ectoparasitic mite Varroa destructor is a major global threat to the Western honeybee Apis mellifera. This mite was originally a parasite of A. cerana in Asia but managed to spill over into colonies of A. mellifera which had been introduced to this continent for honey production. To date, only two almost clonal types of V. destructor from Korea and Japan have been detected in A. mellifera colonies. However, since both A. mellifera and A. cerana colonies are kept in close proximity throughout Asia, not only new spill overs but also spill backs of highly virulent types may be possible, with unpredictable consequences for both honeybee species. We studied the dispersal and hybridisation potential of Varroa from sympatric colonies of the two hosts in Northern Vietnam and the Philippines using mitochondrial and microsatellite DNA markers. We found a very distinct mtDNA haplotype equally invading both A. mellifera and A. cerana in the Philippines. In contrast, we observed a complete reproductive isolation of various Vietnamese Varroa populations in A. mellifera and A. cerana colonies even if kept in the same apiaries. In light of this variance in host specificity, the adaptation of the mite to its hosts seems to have generated much more genetic diversity than previously recognised and the Varroa species complex may include substantial cryptic speciation.

  20. Introduced ascidians harbor highly diverse and host-specific symbiotic microbial assemblages.

    Science.gov (United States)

    Evans, James S; Erwin, Patrick M; Shenkar, Noa; López-Legentil, Susanna

    2017-09-08

    Many ascidian species have experienced worldwide introductions, exhibiting remarkable success in crossing geographic borders and adapting to local environmental conditions. To investigate the potential role of microbial symbionts in these introductions, we examined the microbial communities of three ascidian species common in North Carolina harbors. Replicate samples of the globally introduced species Distaplia bermudensis, Polyandrocarpa anguinea, and P. zorritensis (n = 5), and ambient seawater (n = 4), were collected in Wrightsville Beach, NC. Microbial communities were characterized by next-generation (Illumina) sequencing of partial (V4) 16S rRNA gene sequences. Ascidians hosted diverse symbiont communities, consisting of 5,696 unique microbial OTUs (at 97% sequenced identity) from 47 bacterial and three archaeal phyla. Permutational multivariate analyses of variance revealed clear differentiation of ascidian symbionts compared to seawater bacterioplankton, and distinct microbial communities inhabiting each ascidian species. 103 universal core OTUs (present in all ascidian replicates) were identified, including taxa previously described in marine invertebrate microbiomes with possible links to ammonia-oxidization, denitrification, pathogenesis, and heavy-metal processing. These results suggest ascidian microbial symbionts exhibit a high degree of host-specificity, forming intimate associations that may contribute to host adaptation to new environments via expanded tolerance thresholds and enhanced holobiont function.

  1. Host Specificity in the Honeybee Parasitic Mite, Varroa spp. in Apis mellifera and Apis cerana.

    Science.gov (United States)

    Beaurepaire, Alexis L; Truong, Tuan A; Fajardo, Alejandro C; Dinh, Tam Q; Cervancia, Cleofas; Moritz, Robin F A

    2015-01-01

    The ectoparasitic mite Varroa destructor is a major global threat to the Western honeybee Apis mellifera. This mite was originally a parasite of A. cerana in Asia but managed to spill over into colonies of A. mellifera which had been introduced to this continent for honey production. To date, only two almost clonal types of V. destructor from Korea and Japan have been detected in A. mellifera colonies. However, since both A. mellifera and A. cerana colonies are kept in close proximity throughout Asia, not only new spill overs but also spill backs of highly virulent types may be possible, with unpredictable consequences for both honeybee species. We studied the dispersal and hybridisation potential of Varroa from sympatric colonies of the two hosts in Northern Vietnam and the Philippines using mitochondrial and microsatellite DNA markers. We found a very distinct mtDNA haplotype equally invading both A. mellifera and A. cerana in the Philippines. In contrast, we observed a complete reproductive isolation of various Vietnamese Varroa populations in A. mellifera and A. cerana colonies even if kept in the same apiaries. In light of this variance in host specificity, the adaptation of the mite to its hosts seems to have generated much more genetic diversity than previously recognised and the Varroa species complex may include substantial cryptic speciation.

  2. Extremely strict ideals in Banach spaces

    Indian Academy of Sciences (India)

    Motivated by the notion of an ideal introduced by Godefroy {\\it et al.} ({\\it Studia Math.} {\\bf 104} (1993) 13–59), in this article, we introduce and study the notion of an extremely strict ideal. For a Poulsen simplex K , we show that the space of affine continuous functions on K is an extremely strict ideal in the space of continuous ...

  3. Hyperbolic spaces are of strictly negative type

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Kokkendorff, Simon L.; Markvorsen, Steen

    2002-01-01

    We study finite metric spaces with elements picked from, and distances consistent with, ambient Riemannian manifolds. The concepts of negative type and strictly negative type are reviewed, and the conjecture that hyperbolic spaces are of strictly negative type is settled, in the affirmative...

  4. Extremely strict ideals in Banach spaces

    Indian Academy of Sciences (India)

    Abstract. Motivated by the notion of an ideal introduced by Godefroy et al. (Stu- dia Math. 104 (1993) 13–59), in this article, we introduce and study the notion of an extremely strict ideal. For a Poulsen simplex K, we show that the space of affine contin- uous functions on K is an extremely strict ideal in the space of continuous ...

  5. Comparative host specificity of human- and pig- associated Staphylococcus aureus clonal lineages.

    Directory of Open Access Journals (Sweden)

    Arshnee Moodley

    Full Text Available Bacterial adhesion is a crucial step in colonization of the skin. In this study, we investigated the differential adherence to human and pig corneocytes of six Staphylococcus aureus strains belonging to three human-associated [ST8 (CC8, ST22 (CC22 and ST36(CC30] and two pig-associated [ST398 (CC398 and ST433(CC30] clonal lineages, and their colonization potential in the pig host was assessed by in vivo competition experiments. Corneocytes were collected from 11 humans and 21 pigs using D-squame® adhesive discs, and bacterial adherence to corneocytes was quantified by a standardized light microscopy assay. A previously described porcine colonization model was used to assess the potential of the six strains to colonize the pig host. Three pregnant, S. aureus-free sows were inoculated intravaginally shortly before farrowing with different strain mixes [mix 1 human and porcine ST398; mix 2 human ST36 and porcine ST433; and mix 3 human ST8, ST22, ST36 and porcine ST398] and the ability of individual strains to colonize the nasal cavity of newborn piglets was evaluated for 28 days after birth by strain-specific antibiotic selective culture. In the corneocyte assay, the pig-associated ST433 strain and the human-associated ST22 and ST36 strains showed significantly greater adhesion to porcine and human corneocytes, respectively (p<0.0001. In contrast, ST8 and ST398 did not display preferential host binding patterns. In the in vivo competition experiment, ST8 was a better colonizer compared to ST22, ST36, and ST433 prevailed over ST36 in colonizing the newborn piglets. These results are partly in agreement with previous genetic and epidemiological studies indicating the host specificity of ST22, ST36 and ST433 and the broad-host range of ST398. However, our in vitro and in vivo experiments revealed an unexpected ability of ST8 to adhere to porcine corneocytes and persist in the nasal cavity of pigs.

  6. Parallel Patterns of Host-Specific Morphology and Genetic Admixture in Sister Lineages of a Commensal Barnacle.

    Science.gov (United States)

    Ewers-Saucedo, Christine; Chan, Benny K K; Zardus, John D; Wares, John P

    2017-06-01

    Symbiotic relationships are often species specific, allowing symbionts to adapt to their host environments. Host generalists, on the other hand, have to cope with diverse environments. One coping strategy is phenotypic plasticity, defined by the presence of host-specific phenotypes in the absence of genetic differentiation. Recent work indicates that such host-specific phenotypic plasticity is present in the West Pacific lineage of the commensal barnacle Chelonibia testudinaria (Linnaeus, 1758). We investigated genetic and morphological host-specific structure in the genetically distinct Atlantic sister lineage of C. testudinaria. We collected adult C. testudinaria from loggerhead sea turtles, horseshoe crabs, and blue crabs along the eastern U.S. coast between Delaware and Florida and in the Gulf of Mexico off Mississippi. We find that shell morphology, especially shell thickness, is host specific and comparable in similar host species between the Atlantic and West Pacific lineages. We did not detect significant genetic differentiation related to host species when analyzing data from 11 nuclear microsatellite loci and mitochondrial sequence data, which is comparable to findings for the Pacific lineage. The most parsimonious explanation for these parallel patterns between distinct lineages of C. testudinaria is that C. testudinaria maintained phenotypic plasticity since the lineages diverged 4-5 mya.

  7. Host plant-specific remodeling of midgut physiology in the generalist insect herbivore Trichoplusia ni.

    Science.gov (United States)

    Herde, Marco; Howe, Gregg A

    2014-07-01

    Species diversity in terrestrial ecosystems is influenced by plant defense compounds that alter the behavior, physiology, and host preference of insect herbivores. Although it is established that insects evolved the ability to detoxify specific allelochemicals, the mechanisms by which polyphagous insects cope with toxic compounds in diverse host plants are not well understood. Here, we used defended and non-defended plant genotypes to study how variation in chemical defense affects midgut responses of the lepidopteran herbivore Trichoplusia ni, which is a pest of a wide variety of native and cultivated plants. The genome-wide midgut transcriptional response of T. ni larvae to glucosinolate-based defenses in the crucifer Arabidopsis thaliana was characterized by strong induction of genes encoding Phase I and II detoxification enzymes. In contrast, the response of T. ni to proteinase inhibitors and other jasmonate-regulated defenses in tomato (Solanum lycopersicum) was dominated by changes in the expression of digestive enzymes and, strikingly, concomitant repression of transcripts encoding detoxification enzymes. Unbiased proteomic analyses of T. ni feces demonstrated that tomato defenses remodel the complement of T.ni digestive enzymes, which was associated with increased amounts of serine proteases and decreased lipase protein abundance upon encountering tomato defense chemistry. These collective results indicate that T. ni adjusts its gut physiology to the presence of host plant-specific chemical defenses, and further suggest that plants may exploit this digestive flexibility as a defensive strategy to suppress the production of enzymes that detoxify allelochemicals. Copyright © 2014 Elsevier Ltd. All rights reserved.

  8. Infection, specificity and host manipulation of Australapatemon sp (Trematoda, Strigeidae) in two sympatric species of leeches (Hirudinea)

    Czech Academy of Sciences Publication Activity Database

    Karvonen, A.; Faltýnková, Anna; Choo, J. M.; Valtonen, E. T.

    2017-01-01

    Roč. 144, č. 10 (2017), s. 1346-1355 ISSN 0031-1820 Institutional support: RVO:60077344 Keywords : complex life cycle * Digenea * host manipulation * host-parasite relationship * spatiotemporal variation * specificity * Trematoda Subject RIV: EG - Zoology OBOR OECD: Zoology Impact factor: 2.713, year: 2016

  9. The role of host specificity in explaining the invasion success of the freshwater mussel Anodonta woodiana in Europe

    Czech Academy of Sciences Publication Activity Database

    Douda, K.; Vrtílek, Milan; Slavík, O.; Reichard, Martin

    2012-01-01

    Roč. 14, č. 1 (2012), s. 127-137 ISSN 1387-3547 R&D Projects: GA AV ČR KJB600930802 Institutional research plan: CEZ:AV0Z60930519 Keywords : aquatic habitat * Bivalvia * host-parasite relationship * host specificity * Mollusca Subject RIV: EG - Zoology Impact factor: 2.509, year: 2012

  10. Strain-Specific Features of Extracellular Polysaccharides and Their Impact on Lactobacillus plantarum-Host Interactions.

    Science.gov (United States)

    Lee, I-Chiao; Caggianiello, Graziano; van Swam, Iris I; Taverne, Nico; Meijerink, Marjolein; Bron, Peter A; Spano, Giuseppe; Kleerebezem, Michiel

    2016-07-01

    Lactobacilli are found in diverse environments and are widely applied as probiotic, health-promoting food supplements. Polysaccharides are ubiquitously present on the cell surface of lactobacilli and are considered to contribute to the species- and strain-specific probiotic effects that are typically observed. Two Lactobacillus plantarum strains, SF2A35B and Lp90, have an obvious ropy phenotype, implying high extracellular polysaccharide (EPS) production levels. In this work, we set out to identify the genes involved in EPS production in these L. plantarum strains and to demonstrate their role in EPS production by gene deletion analysis. A model L. plantarum strain, WCFS1, and its previously constructed derivative that produced reduced levels of EPS were included as reference strains. The constructed EPS-reduced derivatives were analyzed for the abundance and sugar compositions of their EPS, revealing cps2-like gene clusters in SF2A35B and Lp90 responsible for major EPS production. Moreover, these mutant strains were tested for phenotypic characteristics that are of relevance for their capacity to interact with the host epithelium in the intestinal tract, including bacterial surface properties as well as survival under the stress conditions encountered in the gastrointestinal tract (acid and bile stress). In addition, the Toll-like receptor 2 (TLR2) signaling and immunomodulatory capacities of the EPS-negative derivatives and their respective wild-type strains were compared, revealing strain-specific impacts of EPS on the immunomodulatory properties. Taken together, these experiments illustrate the importance of EPS in L. plantarum strains as a strain-specific determinant in host interaction. This study evaluates the role of extracellular polysaccharides that are produced by different strains of Lactobacillus plantarum in the determination of the cell surface properties of these bacteria and their capacity to interact with their environment, including their

  11. RNAi screen reveals host cell kinases specifically involved in Listeria monocytogenes spread from cell to cell.

    Directory of Open Access Journals (Sweden)

    Ryan Chong

    Full Text Available Intracellular bacterial pathogens, such as Listeria monocytogenes and Rickettsia conorii display actin-based motility in the cytosol of infected cells and spread from cell to cell through the formation of membrane protrusions at the cell cortex. Whereas the mechanisms supporting cytosolic actin-based motility are fairly well understood, it is unclear whether specific host factors may be required for supporting the formation and resolution of membrane protrusions. To address this gap in knowledge, we have developed high-throughput fluorescence microscopy and computer-assisted image analysis procedures to quantify pathogen spread in human epithelial cells. We used the approach to screen a siRNA library covering the human kinome and identified 7 candidate kinases whose depletion led to severe spreading defects in cells infected with L. monocytogenes. We conducted systematic validation procedures with redundant silencing reagents and confirmed the involvement of the serine/threonine kinases, CSNK1A1 and CSNK2B. We conducted secondary assays showing that, in contrast with the situation observed in CSNK2B-depleted cells, L. monocytogenes formed wild-type cytosolic tails and displayed wild-type actin-based motility in the cytosol of CSNK1A1-depleted cells. Furthermore, we developed a protrusion formation assay and showed that the spreading defect observed in CSNK1A1-depleted cells correlated with the formation of protrusion that did not resolve into double-membrane vacuoles. Moreover, we developed sending and receiving cell-specific RNAi procedures and showed that CSNK1A was required in the sending cells, but was dispensable in the receiving cells, for protrusion resolution. Finally, we showed that the observed defects were specific to Listeria monocytogenes, as Rickettsia conorii displayed wild-type cell-to-cell spread in CSNK1A1- and CSNK2B-depleted cells. We conclude that, in addition to the specific host factors supporting cytosolic actin

  12. Finite Metric Spaces of Strictly negative Type

    DEFF Research Database (Denmark)

    Hjorth, Poul G.

    If a finite metric space is of strictly negative type then its transfinite diameter is uniquely realized by an infinite extent (“load vector''). Finite metric spaces that have this property include all trees, and all finite subspaces of Euclidean and Hyperbolic spaces. We prove that if the distance...... matrix of a finite metric space is both hypermetric and regular, then it is of strictly negative type. We show that the strictly negative type finite subspaces of spheres are precisely those which do not contain two pairs of antipodal points....

  13. Patchy promiscuity: machine learning applied to predict the host specificity ofSalmonella entericaandEscherichia coli.

    Science.gov (United States)

    Lupolova, Nadejda; Dallman, Tim J; Holden, Nicola J; Gally, David L

    2017-10-01

    Salmonella enterica and Escherichia coli are bacterial species that colonize different animal hosts with sub-types that can cause life-threatening infections in humans. Source attribution of zoonoses is an important goal for infection control as is identification of isolates in reservoir hosts that represent a threat to human health. In this study, host specificity and zoonotic potential were predicted using machine learning in which Support Vector Machine (SVM) classifiers were built based on predicted proteins from whole genome sequences. Analysis of over 1000 S. enterica genomes allowed the correct prediction (67 -90 % accuracy) of the source host for S . Typhimurium isolates and the same classifier could then differentiate the source host for alternative serovars such as S . Dublin. A key finding from both phylogeny and SVM methods was that the majority of isolates were assigned to host-specific sub-clusters and had high host-specific SVM scores. Moreover, only a minor subset of isolates had high probability scores for multiple hosts, indicating generalists with genetic content that may facilitate transition between hosts. The same approach correctly identified human versus bovine E. coli isolates (83 % accuracy) and the potential of the classifier to predict a zoonotic threat was demonstrated using E. coli O157. This research indicates marked host restriction for both S. enterica and E. coli , with only limited isolate subsets exhibiting host promiscuity by gene content. Machine learning can be successfully applied to interrogate source attribution of bacterial isolates and has the capacity to predict zoonotic potential.

  14. mtDNA phylogeny of Japanese ant crickets (Orthoptera : Myrmecophilidae): Diversification in host specificity and habitat use

    OpenAIRE

    Komatsu, Takashi; Maruyama, Munetoshi; Ueda, Shouhei; Itino, Takao

    2008-01-01

    Ant crickets (Myrmecophilidae, Orthoptera) are typical ant guests. Although ten species (all belonging to genus Myrmecophilus) have recently been described from Japan, their phylogeny and the extent of host specificity are not known. Here, we reconstruct mtDNA phylogeny of 48 individuals from six species to examine their host specificity, habitat use, and congruence of mtDNA lineages with the morphological species. The cytb phylogeny reveals seven well-supported lineages that in part do not c...

  15. Bacterial leaf symbiosis in angiosperms: host specificity without co-speciation.

    Directory of Open Access Journals (Sweden)

    Benny Lemaire

    Full Text Available Bacterial leaf symbiosis is a unique and intimate interaction between bacteria and flowering plants, in which endosymbionts are organized in specialized leaf structures. Previously, bacterial leaf symbiosis has been described as a cyclic and obligate interaction in which the endosymbionts are vertically transmitted between plant generations and lack autonomous growth. Theoretically this allows for co-speciation between leaf nodulated plants and their endosymbionts. We sequenced the nodulated Burkholderia endosymbionts of 54 plant species from known leaf nodulated angiosperm genera, i.e. Ardisia, Pavetta, Psychotria and Sericanthe. Phylogenetic reconstruction of bacterial leaf symbionts and closely related free-living bacteria indicates the occurrence of multiple horizontal transfers of bacteria from the environment to leaf nodulated plant species. This rejects the hypothesis of a long co-speciation process between the bacterial endosymbionts and their host plants. Our results indicate a recent evolutionary process towards a stable and host specific interaction confirming the proposed maternal transmission mode of the endosymbionts through the seeds. Divergence estimates provide evidence for a relatively recent origin of bacterial leaf symbiosis, dating back to the Miocene (5-23 Mya. This geological epoch was characterized by cool and arid conditions, which may have triggered the origin of bacterial leaf symbiosis.

  16. Hyperbolic spaces are of strictly negative type

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Kokkendorff, Simon L.; Markvorsen, Steen

    2002-01-01

    We study finite metric spaces with elements picked from, and distances consistent with, ambient Riemannian manifolds. The concepts of negative type and strictly negative type are reviewed, and the conjecture that hyperbolic spaces are of strictly negative type is settled, in the affirmative....... The technique of the proof is subsequently applied to show that every compact manifold of negative type must have trivial fundamental group, and to obtain a necessary criterion for product manifolds to be of negative type....

  17. Host-specific microbial communities in three sympatric North Sea sponges

    DEFF Research Database (Denmark)

    Naim, Mohd Azrul; Morillo, Jose A.; Sørensen, Søren Johannes

    2014-01-01

    The establishment of next generation technology sequencing has deepened our knowledge of marine sponge-associated microbiota with the identification of at least 32 phyla of bacteria and archaea from a large number of sponge species. In this study we assessed the diversity of the microbial communi...... in North Sea sponges. These Chlamydiae-affiliated OTUs may represent novel lineages at least at the genus level as they are only 86-92% similar to known sequences. This article is protected by copyright. All rights reserved....... communities hosted by three sympatric sponges living in a semi-enclosed North-Sea environment using pyrosequencing of bacterial and archaeal 16S ribosomal RNA gene fragments. The three sponges harbour species-specific communities each dominated by a different class of Proteobacteria. An α...

  18. Virulence genes and the evolution of host specificity in plant-pathogenic fungi.

    Science.gov (United States)

    van der Does, H Charlotte; Rep, Martijn

    2007-10-01

    In the fungal kingdom, the ability to cause disease in plants appears to have arisen multiple times during evolution. In many cases, the ability to infect particular plant species depends on specific genes that distinguish virulent fungi from their sometimes closely related nonvirulent relatives. These genes encode host-determining "virulence factors," including small, secreted proteins and enzymes involved in the synthesis of toxins. These virulence factors typically are involved in evolutionary arms races between plants and pathogens. We briefly summarize current knowledge of these virulence factors from several fungal species in terms of function, phylogenetic distribution, sequence variation, and genomic location. Second, we address some issues that are relevant to the evolution of virulence in fungi toward plants; in particular, horizontal gene transfer and the genomic organization of virulence genes.

  19. Host-specific interactions with environmental factors shape the distribution of symbiodinium across the Great Barrier Reef.

    Directory of Open Access Journals (Sweden)

    Linda Tonk

    Full Text Available The endosymbiotic dinoflagellates (genus Symbiodinium within coral reef invertebrates are critical to the survival of the holobiont. The genetic variability of Symbiodinium may contribute to the tolerance of the symbiotic association to elevated sea surface temperatures (SST. To assess the importance of factors such as the local environment, host identity and biogeography in driving Symbiodinium distributions on reef-wide scales, data from studies on reef invertebrate-Symbiodinium associations from the Great Barrier Reef (GBR were compiled.The resulting database consisted of 3717 entries from 26 studies. It was used to explore ecological patterns such as host-specificity and environmental drivers structuring community complexity using a multi-scalar approach. The data was analyzed in several ways: (i frequently sampled host species were analyzed independently to investigate the influence of the environment on symbiont distributions, thereby excluding the influence of host specificity, (ii host species distributions across sites were added as an environmental variable to determine the contribution of host identity on symbiont distribution, and (iii data were pooled based on clade (broad genetic groups dividing the genus Symbiodinium to investigate factors driving Symbiodinium distributions using lower taxonomic resolution. The results indicated that host species identity plays a dominant role in determining the distribution of Symbiodinium and environmental variables shape distributions on a host species-specific level. SST derived variables (especially SSTstdev most often contributed to the selection of the best model. Clade level comparisons decreased the power of the predictive model indicating that it fails to incorporate the main drivers behind Symbiodinium distributions.Including the influence of different host species on Symbiodinium distributional patterns improves our understanding of the drivers behind the complexity of Symbiodinium

  20. Density-dependent sex ratio and sex-specific preference for host traits in parasitic bat flies.

    Science.gov (United States)

    Szentiványi, Tamara; Vincze, Orsolya; Estók, Péter

    2017-08-29

    Deviation of sex ratios from unity in wild animal populations has recently been demonstrated to be far more prevalent than previously thought. Ectoparasites are prominent examples of this bias, given that their sex ratios vary from strongly female- to strongly male-biased both among hosts and at the metapopulation level. To date our knowledge is very limited on how and why these biased sex ratios develop. It was suggested that sex ratio and sex-specific aggregation of ectoparasites might be shaped by the ecology, behaviour and physiology of both hosts and their parasites. Here we investigate a highly specialised, hematophagous bat fly species with strong potential to move between hosts, arguably limited inbreeding effects, off-host developmental stages and extended parental care. We collected a total of 796 Nycteribia kolenatii bat flies from 147 individual bats using fumigation and subsequently determined their sex. We report a balanced sex ratio at the metapopulation level and a highly variable sex ratio among infrapopulations ranging from 100% male to 100% female. We show that infrapopulation sex ratio is not random and is highly correlated with infrapopulation size. Sex ratio is highly male biased in small and highly female biased in large infrapopulations. We show that this pattern is most probably the result of sex-specific preference in bat flies for host traits, most likely combined with a higher mobility of males. We demonstrate that female bat flies exert a strong preference for high host body condition and female hosts, while the distribution of males is more even. Our results suggest that locally biased sex ratios can develop due to sex-specific habitat preference of parasites. Moreover, it is apparent that the sex of both hosts and parasites need to be accounted for when a better understanding of host-parasite systems is targeted.

  1. Host-specific interactions with environmental factors shape the distribution of symbiodinium across the Great Barrier Reef.

    Science.gov (United States)

    Tonk, Linda; Sampayo, Eugenia M; Weeks, Scarla; Magno-Canto, Marites; Hoegh-Guldberg, Ove

    2013-01-01

    The endosymbiotic dinoflagellates (genus Symbiodinium) within coral reef invertebrates are critical to the survival of the holobiont. The genetic variability of Symbiodinium may contribute to the tolerance of the symbiotic association to elevated sea surface temperatures (SST). To assess the importance of factors such as the local environment, host identity and biogeography in driving Symbiodinium distributions on reef-wide scales, data from studies on reef invertebrate-Symbiodinium associations from the Great Barrier Reef (GBR) were compiled. The resulting database consisted of 3717 entries from 26 studies. It was used to explore ecological patterns such as host-specificity and environmental drivers structuring community complexity using a multi-scalar approach. The data was analyzed in several ways: (i) frequently sampled host species were analyzed independently to investigate the influence of the environment on symbiont distributions, thereby excluding the influence of host specificity, (ii) host species distributions across sites were added as an environmental variable to determine the contribution of host identity on symbiont distribution, and (iii) data were pooled based on clade (broad genetic groups dividing the genus Symbiodinium) to investigate factors driving Symbiodinium distributions using lower taxonomic resolution. The results indicated that host species identity plays a dominant role in determining the distribution of Symbiodinium and environmental variables shape distributions on a host species-specific level. SST derived variables (especially SSTstdev) most often contributed to the selection of the best model. Clade level comparisons decreased the power of the predictive model indicating that it fails to incorporate the main drivers behind Symbiodinium distributions. Including the influence of different host species on Symbiodinium distributional patterns improves our understanding of the drivers behind the complexity of Symbiodinium

  2. Asymmetric hybridization and gene flow between Joshua trees (Agavaceae: Yucca) reflect differences in pollinator host specificity.

    Science.gov (United States)

    Starr, Tyler N; Gadek, Katherine E; Yoder, Jeremy B; Flatz, Ramona; Smith, Christopher I

    2013-01-01

    The angiosperms are by far the largest group of terrestrial plants. Their spectacular diversity is often attributed to specialized pollination. Obligate pollination mutualisms where both a plant and its pollinator are dependent upon one another for reproduction are thought to be prone to rapid diversification through co-evolution and pollinator isolation. However, few studies have evaluated the degree to which pollinators actually mediate reproductive isolation in these systems. Here, we examine evidence for hybridization and gene flow between two subspecies of Joshua tree (Yucca brevifolia brevifolia and Yucca brevifolia jaegeriana) pollinated by two sister species of yucca moth. Previous work indicated that the pollinators differ in host specificity, and DNA sequence data suggested asymmetric introgression between the tree subspecies. Through intensive sampling in a zone of sympatry, a large number of morphologically intermediate trees were identified. These included trees with floral characters typical of Y. b. jaegeriana, but vegetative features typical of Y. b. brevifolia. The opposite combination-Y. b. brevifolia flowers with Y. b. jaegeriana vegetative morphology-never occurred. Microsatellite genotyping revealed a high frequency of genetically admixed, hybrid trees. Coalescent-based estimates of migration indicated significant gene flow between the subspecies and that the direction of gene flow matches differences in pollinator host fidelity. The data suggest that pollinator behaviour determines the magnitude and direction of gene flow between the two subspecies, but that specialized pollination alone is not sufficient to maintain species boundaries. Natural selection may be required to maintain phenotypic differences in the face of ongoing gene flow. © 2012 Blackwell Publishing Ltd.

  3. Host specificity and genetic differentiation of Melampsora epitea (rust on willows)

    Energy Technology Data Exchange (ETDEWEB)

    Hurtado Pasten, Sergio [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Plant Pathology and Biocontrol Unit

    2001-07-01

    Rust caused by Melampsora epitea is considered the most serious and widespread disease on willows. When severe, rust can defoliate willows prematurely leading to serious yield losses and rootstock death. Studying the infection process, we found that M. epitea requires no specific recognition signals to germinate, grow, or penetrate the host stomata, regardless of whether interaction with the host plant is compatible or incompatible; instead, plant defense mechanisms are determined by substomatal events. Isolates of the Swedish rust population were classified (pathotyped) by their virulence patterns on a standard set of willow clones (willow differential). Thirty-seven pathotypes of M. epitea were identified and grouped into three formae speciales. For global monitoring of the virulence of M. epitea, an internationally useful naming system was proposed. Partly to confirm the value of such a naming system, the pathotype compositions of two distant M. epitea populations (from Sweden and Chile) were compared using the willow differential. The results indicated that long-distance inocula exchange likely plays an active role in the population dynamics and evolution of pathotype structure for M. epitea. To study the genetics underlying pathotype dynamics, molecular tools, such as AFLP, were used. The resulting dendrogram revealed no clustering based on geographic origin, and because geographic distance among pathogen populations correlated poorly with genetic distance, apparently geographically distant populations have developed collectively as a metapopulation instead of separately. However, the result shows that M. epitea has high levels of gene and genotypic variation within populations, which is consistent with the occurrence of sexual reproduction. The low between-population variation, despite variation in local selection pressures, accords with massive long-distance migration of rust spores.

  4. Rhesus macaques (Macaca mulatta are natural hosts of specific Staphylococcus aureus lineages.

    Directory of Open Access Journals (Sweden)

    Sanne van den Berg

    Full Text Available Currently, there is no animal model known that mimics natural nasal colonization by Staphylococcus aureus in humans. We investigated whether rhesus macaques are natural nasal carriers of S. aureus. Nasal swabs were taken from 731 macaques. S. aureus isolates were typed by pulsed-field gel electrophoresis (PFGE, spa repeat sequencing and multi-locus sequence typing (MLST, and compared with human strains. Furthermore, the isolates were characterized by several PCRs. Thirty-nine percent of 731 macaques were positive for S. aureus. In general, the macaque S. aureus isolates differed from human strains as they formed separate PFGE clusters, 50% of the isolates were untypeable by agr genotyping, 17 new spa types were identified, which all belonged to new sequence types (STs. Furthermore, 66% of macaque isolates were negative for all superantigen genes. To determine S. aureus nasal colonization, three nasal swabs from 48 duo-housed macaques were taken during a 5 month period. In addition, sera were analyzed for immunoglobulin G and A levels directed against 40 staphylococcal proteins using a bead-based flow cytometry technique. Nineteen percent of the animals were negative for S. aureus, and 17% were three times positive. S. aureus strains were easily exchanged between macaques. The antibody response was less pronounced in macaques compared to humans, and nasal carrier status was not associated with differences in serum anti-staphylococcal antibody levels. In conclusion, rhesus macaques are natural hosts of S. aureus, carrying host-specific lineages. Our data indicate that rhesus macaques are useful as an autologous model for studying S. aureus nasal colonization and infection prevention.

  5. Experimental evolution of parasitoid infectivity on symbiont-protected hosts leads to the emergence of genotype specificity.

    Science.gov (United States)

    Rouchet, Romain; Vorburger, Christoph

    2014-06-01

    Host-parasitoid interactions may lead to strong reciprocal selection for traits involved in host defense and parasitoid counterdefense. In aphids, individuals harboring the facultative bacterial endosymbiont, Hamiltonella defensa, exhibit enhanced resistance to parasitoid wasps. We used an experimental evolution approach to investigate the ability of the parasitoid wasp, Lysiphlebus fabarum, to adapt to the presence of H. defensa in its aphid host Aphis fabae. Sexual populations of the parasitoid were exposed for 11 generations to a single clone of A. fabae, either free of H. defensa or harboring artificial infections with three different isolates of H. defensa. Parasitoids adapted rapidly to the presence of H. defensa in their hosts, but this adaptation was in part specific to the symbiont isolate they were evolving against and did not result in an improved infectivity on all symbiont-protected hosts. Comparisons of life-history traits among the evolved lines of parasitoids did not reveal any evidence for costs of adaptation to H. defensa in terms of correlated responses that could constrain such adaptation. These results show that parasitoids readily evolve counter-adaptations to heritable defensive symbionts of their hosts, but that different symbiont strains impose different evolutionary challenges. The symbionts thus mediate the host-parasite interaction by inducing line-by-line genetic specificity. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  6. Filarial-specific antibody response in East African bancroftian filariasis: effects of host infection, clinical disease, and filarial endemicity

    DEFF Research Database (Denmark)

    Jaoko, Walter G; Simonsen, Paul E; Meyrowitsch, Dan W

    2006-01-01

    The effect of host infection, chronic clinical disease, and transmission intensity on the patterns of specific antibody responses in Bancroftian filariasis was assessed by analyzing specific IgG1, IgG2, IgG3, IgG4, and IgE profiles among adults from two communities with high and low Wuchereria...

  7. Host Specificity of Amblyomma cajennense (Fabricius, 1787 (Acari: Ixodidae with Comments on the Drop-off Rhythm

    Directory of Open Access Journals (Sweden)

    Cristina Marques Lisbôa Lopes

    1998-05-01

    Full Text Available The parasitic specificity of larval, nymph and adult Amblyomma cajennense on six different host species: Oryctolagus cuniculus, Rattus norvegicus, Gallus gallus domesticus, Anas platyrhynchus, Coturnix coturnix and Streptopelia decorata is described. In terms of the numbers of larvae and nymphs recovered, O. cuniculus was the best host species. The modal day for drop-off of larvae and nymphs was day three for the mammal hosts, but variable in the birds. We conclude that adult A. cajennense have a strong degree of specificity due to the fact that the tick failed to complete its life cycle on any of the evaluated hosts. The immature stages, on the other hand, showed a low level of specificity, most especially in the larval stage, indicating the existence of secondary hosts which probably serve as dispersers in the wild. The results also indicated a variable drop-off rhythm for larvae and nymphs in two periods, diurnal (6-18 hr and nocturnal (18-6 hr, which differed depending upon the host.

  8. Genotype-specific interactions and the trade-off between host and parasite fitness

    Directory of Open Access Journals (Sweden)

    Shykoff Jacqui A

    2007-10-01

    Full Text Available Abstract Background Evolution of parasite traits is inextricably linked to their hosts. For instance one common definition of parasite virulence is the reduction in host fitness due to infection. Thus, traits of infection must be viewed in both protagonists and may be under shared genetic and physiological control. We investigated these questions on the oomycete Hyaloperonospora arabidopsis (= parasitica, a natural pathogen of the Brassicaceae Arabidopsis thaliana. Results We performed a controlled cross inoculation experiment confronting six lines of the host plant with seven strains of the parasite in order to evaluate genetic variation for phenotypic traits of infection among hosts, parasites, and distinct combinations. Parasite infection intensity and transmission were highly variable among parasite strains and host lines but depended also on the interaction between particular genotypes of the protagonists, and genetic variation for the infection phenotype of parasites from natural populations was found even at a small spatial scale within population. Furthermore, increased parasite fitness led to a significant decrease in host fitness only on a single host line (Gb, although a trade-off between these two traits was expected because host and parasite share the same resource pool for their respective reproduction. We propose that different levels of compatibility dependent on genotype by genotype interactions might lead to different amounts of resources available for host and parasite reproduction. This variation in compatibility could thus mask the expected negative relationship between host and parasite fitness, as the total resource pool would not be constant. Conclusion These results highlight the importance of host variation in the determination of parasite fitness traits. This kind of interaction may in turn decouple the relationship between parasite transmission and its negative effect on host fitness, altering theoretical predictions

  9. Chromosomal rearrangements formed by rrn recombination do not improve replichore balance in host-specific Salmonella enterica serovars.

    Directory of Open Access Journals (Sweden)

    T David Matthews

    2010-10-01

    Full Text Available Most of the ∼2,600 serovars of Salmonella enterica have a broad host range as well as a conserved gene order. In contrast, some Salmonella serovars are host-specific and frequently exhibit large chromosomal rearrangements from recombination between rrn operons. One hypothesis explaining these rearrangements suggests that replichore imbalance introduced from horizontal transfer of pathogenicity islands and prophages drives chromosomal rearrangements in an attempt to improve balance.This hypothesis was directly tested by comparing the naturally-occurring chromosomal arrangement types to the theoretically possible arrangement types, and estimating their replichore balance using a calculator. In addition to previously characterized strains belonging to host-specific serovars, the arrangement types of 22 serovar Gallinarum strains was also determined. Only 48 out of 1,440 possible arrangement types were identified in 212 host-specific strains. While the replichores of most naturally-occurring arrangement types were well-balanced, most theoretical arrangement types had imbalanced replichores. Furthermore, the most common types of rearrangements did not change replichore balance.The results did not support the hypothesis that replichore imbalance causes these rearrangements, and suggest that the rearrangements could be explained by aspects of a host-specific lifestyle.

  10. Specific Mutations in H5N1 Mainly Impact the Magnitude and Velocity of the Host Response in Mice

    Energy Technology Data Exchange (ETDEWEB)

    Tchitchek, Nicholas; Eisfeld, Amie J.; Tisoncik-Go, Jennifer; Josset, Laurence; Gralinski, Lisa; Becavin, Christophe; Tilton, Susan C.; Webb-Robertson, Bobbie-Jo M.; Ferris, Martin T.; Totura, Allison L.; Li, Chengjun; Neumann, Gabriele; Metz, Thomas O.; Smith, Richard D.; Waters, Katrina M.; Baric, Ralph; Kawaoka, Yoshihiro; Katze, Michael G.

    2013-07-29

    Influenza infection causes respiratory disease that can lead to death. The complex interplay between virus-encoded and host-specific pathogenicity regulators is not well-understood. By analyzing a collection of mouse lung samples infected by A/Vietnam/1203/2004 (H5N1; VN1203) influenza, we characterized a signature of transcripts and proteins associated with the kinetics of the host response. Using a new geometrical representation method and two criteria, we show that infection concentrations and four specific mutations in VN1203 mainly impact on the magnitude and velocity of the host response kinetics, rather than on specific sets of genes up- and down-regulated. We observed similar kinetic effects using A/California/04/2009 (H1N1)-infected samples, and we show that these effects correlate with mice morbidity and viral titer measurements. Speed and extent of changes in the host response between days 1 and 2 post-infection were attenuated for each VN1203 mutant compared to the wild-type, except for PB1-F2 deletion at a high dose, which was associated with high virulence. This indicates that the host response in that time frame is critical and that immunomodulatory therapeutics should specifically be applied during the early days post-infection.

  11. A novel Capsicum gene inhibits host-specific disease resistance to Phytophthora capsici.

    Science.gov (United States)

    Reeves, Gregory; Monroy-Barbosa, Ariadna; Bosland, Paul W

    2013-05-01

    A novel disease resistance inhibitor gene (inhibitor of P. capsici resistance [Ipcr]), found in the chile pepper (Capsicum annuum) variety 'New Mexico Capsicum Accession 10399' (NMCA10399), inhibits resistance to Phytophthora capsici but not to other species of Phytophthora. When a highly P. capsici-resistant variety was hybridized with NMCA10399, the resultant F1 populations, when screened, were completely susceptible to P. capsici for root rot and foliar blight disease syndromes, despite the dominance inheritance of P. capsici resistance in chile pepper. The F2 population displayed a 3:13 resistant-to-susceptible (R:S) ratio. The testcross population displayed a 1:1 R:S ratio, and a backcross population to NMCA10399 displayed complete susceptibility. These results demonstrate the presence of a single dominant inhibitor gene affecting P. capsici resistance in chile pepper. Moreover, when lines carrying the Ipcr gene were challenged against six Phytophthora spp., the nonhost resistance was not overcome. Therefore, the Ipcr gene is interfering with host-specific resistance but not the pathogen- or microbe-associated molecular pattern nonhost responses.

  12. Strictly convex functions on complete Finsler manifolds

    Indian Academy of Sciences (India)

    ... Refresher Courses · Symposia · Live Streaming. Home; Journals; Proceedings – Mathematical Sciences; Volume 126; Issue 4. Strictly convex functions on complete Finsler manifolds. YOE ITOKAWA KATSUHIRO SHIOHAMA BANKTESHWAR TIWARI. Research Article Volume 126 Issue 4 October 2016 pp 623-627 ...

  13. Finite Metric Spaces of Strictly Negative Type

    DEFF Research Database (Denmark)

    Hjorth, Poul; Lisonek, P.; Markvorsen, Steen

    1998-01-01

    We prove that, if a finite metric space is of strictly negative type, then its transfinite diameter is uniquely realized by the infinite extender (load vector). Finite metric spaces that have this property include all spaces on two, three, or four points, all trees, and all finite subspaces of Eu...

  14. Survival and persistence of fecal host-specific Bacteroidales cells and their DNA assessed by PMA-qPCR

    Science.gov (United States)

    Bae, S.; Bombardelli, F.; Wuertz, S.

    2008-12-01

    Understanding and managing microbial pollutions in water is one of the foremost challenges of establishing effective managements and remediation strategies to impaired water bodies polluted by uncharacterized fecal sources. Quantitative microbial source tracking (MST) approaches using fecal Bacteroidales and quantitative PCR (qPCR) assays to measure gene copies of host-specific 16S rRNA genetic markers are promising because they can allow for identifying and quantifying fecal loadings from a particular animal host and understanding the fate and transport of host-specific Bacteroidales over a range of conditions in water bodies. Similar to the case of traditional fecal indicator bacteria, a relatively long persistence of target DNA may hamper applied MST studies, if genetic markers cannot be linked to recent fecal pollution in water. We report a successful approach to removing the qPCR signal derived from free DNA and dead host-specific Bacteroidales cells by selectively binding the DNA and consequently inhibiting PCR amplification using light- activated propidium monoazide (PMA). Optimal PMA-qPCR conditions were determined as 100 µM of PMA concentration and a 10-min light exposure time at different solids concentrations in order to mimic a range of water samples. Under these conditions, PMA-qPCR resulted in the selective exclusion of DNA from heat- treated cells of non-culturable Bacteroidales in human feces and wastewater influent and effluent samples. Also, the persistence of feces-derived host-specific Bacteroidales DNA and their cells (determined by universal, human-, cow- and dog-specific Bacteroidales qPCR assays) in seawater was investigated in microcosms at environmental conditions. The average T99 (two log reduction) value for host-specific viable Bacteroidales cells was 28 h, whereas that for total host-specific Bacteroidales DNA was 177 h. Natural sunlight did not have a strong influence on the fate of fecal Bacteroidales cells and their DNA, presumably

  15. Host Specificity of Argopistes tsekooni (Coleoptera: Chrysomelidae), a Potential Biological Control Agent of Chinese Privet

    Science.gov (United States)

    Yan Zhuo Zhang; James Hanula; Jiang Hua Sun

    2008-01-01

    Chinese privet, Ligustrum sinense Lour., is a perennial semi-evergreen shrub that is aserious invasive weed in the United States. Classical biological control offers the best hope forcontrolling it in an economic, effective, and persistent way. Host...

  16. Host-Specificity and Dynamics in Bacterial Communities Associated with Bloom-Forming Freshwater Phytoplankton

    Science.gov (United States)

    Bagatini, Inessa Lacativa; Eiler, Alexander; Bertilsson, Stefan; Klaveness, Dag; Tessarolli, Letícia Piton; Vieira, Armando Augusto Henriques

    2014-01-01

    Many freshwater phytoplankton species have the potential to form transient nuisance blooms that affect water quality and other aquatic biota. Heterotrophic bacteria can influence such blooms via nutrient regeneration but also via antagonism and other biotic interactions. We studied the composition of bacterial communities associated with three bloom-forming freshwater phytoplankton species, the diatom Aulacoseira granulata and the cyanobacteria Microcystis aeruginosa and Cylindrospermopsis raciborskii. Experimental cultures incubated with and without lake bacteria were sampled in three different growth phases and bacterial community composition was assessed by 454-Pyrosequencing of 16S rRNA gene amplicons. Betaproteobacteria were dominant in all cultures inoculated with lake bacteria, but decreased during the experiment. In contrast, Alphaproteobacteria, which made up the second most abundant class of bacteria, increased overall during the course of the experiment. Other bacterial classes responded in contrasting ways to the experimental incubations causing significantly different bacterial communities to develop in response to host phytoplankton species, growth phase and between attached and free-living fractions. Differences in bacterial community composition between cyanobacteria and diatom cultures were greater than between the two cyanobacteria. Despite the significance, major differences between phytoplankton cultures were in the proportion of the OTUs rather than in the absence or presence of specific taxa. Different phytoplankton species favoring different bacterial communities may have important consequences for the fate of organic matter in systems where these bloom forming species occur. The dynamics and development of transient blooms may also be affected as bacterial communities seem to influence phytoplankton species growth in contrasting ways. PMID:24465807

  17. Host-specificity and dynamics in bacterial communities associated with Bloom-forming freshwater phytoplankton.

    Directory of Open Access Journals (Sweden)

    Inessa Lacativa Bagatini

    Full Text Available Many freshwater phytoplankton species have the potential to form transient nuisance blooms that affect water quality and other aquatic biota. Heterotrophic bacteria can influence such blooms via nutrient regeneration but also via antagonism and other biotic interactions. We studied the composition of bacterial communities associated with three bloom-forming freshwater phytoplankton species, the diatom Aulacoseira granulata and the cyanobacteria Microcystis aeruginosa and Cylindrospermopsis raciborskii. Experimental cultures incubated with and without lake bacteria were sampled in three different growth phases and bacterial community composition was assessed by 454-Pyrosequencing of 16S rRNA gene amplicons. Betaproteobacteria were dominant in all cultures inoculated with lake bacteria, but decreased during the experiment. In contrast, Alphaproteobacteria, which made up the second most abundant class of bacteria, increased overall during the course of the experiment. Other bacterial classes responded in contrasting ways to the experimental incubations causing significantly different bacterial communities to develop in response to host phytoplankton species, growth phase and between attached and free-living fractions. Differences in bacterial community composition between cyanobacteria and diatom cultures were greater than between the two cyanobacteria. Despite the significance, major differences between phytoplankton cultures were in the proportion of the OTUs rather than in the absence or presence of specific taxa. Different phytoplankton species favoring different bacterial communities may have important consequences for the fate of organic matter in systems where these bloom forming species occur. The dynamics and development of transient blooms may also be affected as bacterial communities seem to influence phytoplankton species growth in contrasting ways.

  18. Plant-associated odor perception and processing in two parasitoid species with different degrees of host specificity: Implications for host location strategies.

    Science.gov (United States)

    Das, Prithwiraj; Morawo, Tolulope; Fadamiro, Henry

    2017-08-01

    Microplitis croceipes and Cotesia marginiventris (Hymenoptera: Braconidae) are parasitoids of lepidopteran larvae with different degrees of host specificity. Both parasitoid species rely on host-related plant volatiles as odor cues to locate their herbivore hosts. To better understand mechanisms of odor processing in parasitoids, we tested responses of olfactory sensory neurons (OSNs) in the antennal sensilla placodea of female parasitoids to select plant volatiles and mixtures. The compounds tested include two green leaf volatiles (i.e., cis-3-hexenol and hexanal) and three herbivore-induced plant volatiles (i.e., cis-3-hexenyl butyrate, cis-3-hexenyl acetate and linalool). Single-sensillum recording showed that the test compounds elicited activity in large and small amplitude neurons housed in the short sensilla placodea of both parasitoid species. In general, C. marginiventris showed greater OSN responses to a low dose while M. croceipes showed greater responses to a high dose of test compounds. Binary mixtures of cis-3-hexenol and linalool inhibited OSN activity in M. croceipes, but not in C. marginiventris. These differences may have implications for odor discrimination in the two parasitoid species. In addition, anterograde neurobiotin stainings were performed to map glomerular projections of OSNs in the antennal lobe of the parasitoids. In M. croceipes, a mixture of cis-3-hexenol and linalool inhibited activity of the glomerulus activated by cis-3-hexenol alone. In C. marginiventris, a mixture of cis-3-hexenol and cis-3-hexenyl acetate showed intense labeling in their respective glomeruli, possibly suggesting a synergistic interaction. These differences in detection and coding of single compounds and mixtures may impact host location strategies in the two parasitoid species. Copyright © 2017 Elsevier Ltd. All rights reserved.

  19. Assessing the diversity, host-specificity and infection patterns of apicomplexan parasites in reptiles from Oman, Arabia.

    Science.gov (United States)

    Maia, João P; Harris, D James; Carranza, Salvador; Goméz-Díaz, Elena

    2016-11-01

    Understanding the processes that shape parasite diversification, their distribution and abundance provides valuable information on the dynamics and evolution of disease. In this study, we assessed the diversity, distribution, host-specificity and infection patterns of apicomplexan parasites in amphibians and reptiles from Oman, Arabia. Using a quantitative PCR approach we detected three apicomplexan parasites (haemogregarines, lankesterellids and sarcocystids). A total of 13 haemogregarine haplotypes were identified, which fell into four main clades in a phylogenetic framework. Phylogenetic analysis of six new lankesterellid haplotypes revealed that these parasites were distinct from, but phylogenetically related to, known Lankesterella species and might represent new taxa. The percentage of infected hosts (prevalence) and the number of haemogregarines in the blood (parasitaemia) varied significantly between gecko species. We also found significant differences in parasitaemia between haemogregarine parasite lineages (defined by phylogenetic clustering of haplotypes), suggesting differences in host-parasite compatibility between these lineages. For Pristurus rupestris, we found significant differences in haemogregarine prevalence between geographical areas. Our results suggest that host ecology and host relatedness may influence haemogregarine distributions and, more generally, highlight the importance of screening wild hosts from remote regions to provide new insights into parasite diversity.

  20. Infection by Toxoplasma gondii Specifically Induces Host c-Myc and the Genes This Pivotal Transcription Factor Regulates

    Science.gov (United States)

    Franco, Magdalena; Shastri, Anjali J.

    2014-01-01

    Toxoplasma gondii infection has previously been described to cause dramatic changes in the host transcriptome by manipulating key regulators, including STATs, NF-κB, and microRNAs. Here, we report that Toxoplasma tachyzoites also mediate rapid and sustained induction of another pivotal regulator of host cell transcription, c-Myc. This induction is seen in cells infected with all three canonical types of Toxoplasma but not the closely related apicomplexan parasite Neospora caninum. Coinfection of cells with both Toxoplasma and Neospora still results in an increase in the level of host c-Myc, showing that c-Myc is actively upregulated by Toxoplasma infection (rather than repressed by Neospora). We further demonstrate that this upregulation may be mediated through c-Jun N-terminal protein kinase (JNK) and is unlikely to be a nonspecific host response, as heat-killed Toxoplasma parasites do not induce this increase and neither do nonviable parasites inside the host cell. Finally, we show that the induced c-Myc is active and that transcripts dependent on its function are upregulated, as predicted. Hence, c-Myc represents an additional way in which Toxoplasma tachyzoites have evolved to specifically alter host cell functions during intracellular growth. PMID:24532536

  1. Host-specific phenotypic plasticity of the turtle barnacle Chelonibia testudinaria: a widespread generalist rather than a specialist.

    Directory of Open Access Journals (Sweden)

    Chi Chiu Cheang

    Full Text Available Turtle barnacles are common epibionts on marine organisms. Chelonibia testudinaria is specific on marine turtles whereas C. patula is a host generalist, but rarely found on turtles. It has been questioned why C. patula, being abundant on a variety of live substrata, is almost absent from turtles. We evaluated the genetic (mitochondrial COI, 16S and 12S rRNA, and amplified fragment length polymorphism (AFLP and morphological differentiation of C. testudinaia and C. patula from different hosts, to determine the mode of adaptation exhibited by Chelonibia species on different hosts. The two taxa demonstrate clear differences in shell morphology and length of 4-6(th cirri, but very similar in arthropodal characters. Moreover, we detected no genetic differentiation in mitochondrial DNA and AFLP analyses. Outlier detection infers insignificant selection across loci investigated. Based on combined morphological and molecular evidence, we proposed that C. testudinaria and C. patula are conspecific, and the two morphs with contrasting shell morphologies and cirral length found on different host are predominantly shaped by developmental plasticity in response to environmental setting on different hosts. Chelonibia testudinaria is, thus, a successful general epibiotic fouler and the phenotypic responses postulated can increase the fitness of the animals when they attach on hosts with contrasting life-styles.

  2. Extremely strict ideals in Banach spaces

    Indian Academy of Sciences (India)

    the space of regular Borel measures, it is easy to see that with respect to the projection μ → μ|(0, 1), M is an extremely strict ideal in C([0, 1]) but as the Lebesgue measure is non-atomic, M. ∗. 1 is not the norm closed ..... (Grenoble) 28 (1978) 35–65. [10] Rao T S S R K, On ideals in Banach spaces, Rocky Mountain J. Math.

  3. Lack of host specificity leads to independent assortment of dipterocarps and ectomycorrhizal fungi across a soil fertility gradient.

    Science.gov (United States)

    Peay, Kabir G; Russo, Sabrina E; McGuire, Krista L; Lim, Zhenyu; Chan, Ju Ping; Tan, Sylvester; Davies, Stuart J

    2015-08-01

    Plants interact with a diversity of microorganisms, and there is often concordance in their community structures. Because most community-level studies are observational, it is unclear if such concordance arises because of host specificity, in which microorganisms or plants limit each other's occurrence. Using a reciprocal transplant experiment, we tested the hypothesis that host specificity between trees and ectomycorrhizal fungi determines patterns of tree and fungal soil specialisation. Seedlings of 13 dipterocarp species with contrasting soil specialisations were seeded into plots crossing soil type and canopy openness. Ectomycorrhizal colonists were identified by DNA sequencing. After 2.5 years, we found no evidence of host specificity. Rather, soil environment was the primary determinant of ectomycorrhizal diversity and composition on seedlings. Despite their close symbiosis, our results show that ectomycorrhizal fungi and tree communities in this Bornean rain forest assemble independently of host-specific interactions, raising questions about how mutualism shapes the realised niche. © 2015 John Wiley & Sons Ltd/CNRS.

  4. Host specificity and genealogy of Polyplax serrata on Apodemus species: a case of parasite duplication or colonisation?

    Czech Academy of Sciences Publication Activity Database

    Štefka, Jan; Hypša, Václav

    2008-01-01

    Roč. 38, č. 6 (2008), s. 731-741 ISSN 0020-7519 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60220518 Keywords : parasite duplication * host specificity * genealogy * speciation * Polyplax * Apodemus Subject RIV: EH - Ecology, Behaviour Impact factor: 3.752, year: 2008

  5. Mannose-specific interactions of Lactobacillus plantarum in the intestine : bacterial genes, molecular host responses and potential probiotic effects

    NARCIS (Netherlands)

    Pretzer, G.

    2008-01-01

    One potential mechanism by which probiotic microorganisms may exert beneficial health effects to the host is the inhibition of intestinal infections by competitive exclusion of pathogenic bacteria. This concept may also be applicable for mannose-specific adhesion to the epithelial surface, which has

  6. Host-specificity of monoxenous trypanosomatids: statistical analysis of the distribution and transmission patterns of the parasites from Neotropical Heteroptera

    Czech Academy of Sciences Publication Activity Database

    Kozminsky, E.; Kraeva, N.; Ishemgulova, A.; Dobáková, Eva; Lukeš, Julius; Kment, P.; Yurchenko, V.; Votýpka, J.; Maslov, D. A.

    2015-01-01

    Roč. 166, č. 5 (2015), s. 551-568 ISSN 1434-4610 R&D Projects: GA ČR(CZ) GA14-23986S Institutional support: RVO:60077344 Keywords : Trypanosomatids * Heteroptera * host-parasite specificity * biodiversity * Spliced Leader RNA Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 2.898, year: 2015

  7. DYNAMICS OF AQUATIC FECAL CONTAMINATION, FECAL SOURCE IDENTIFICATION, AND CORRELATION OF BACTEROIDALES HOST-SPECIFIC MARKERS DETECTION WITH FECAL PATHOGENS

    Science.gov (United States)

    Fecal pollution impairs the health and productivity of coastal waters and causes human disease. PCR of host-specific 16S rDNA sequences from anaerobic Bacteroidales bacteria offers a promising method of tracking fecal contamination and identifying its source(s). Before Bacteroida...

  8. Extracellular vesicles from parasitic helminths contain specific excretory/secretory proteins and are internalized in intestinal host cells.

    Directory of Open Access Journals (Sweden)

    Antonio Marcilla

    Full Text Available The study of host-parasite interactions has increased considerably in the last decades, with many studies focusing on the identification of parasite molecules (i.e. surface or excretory/secretory proteins (ESP as potential targets for new specific treatments and/or diagnostic tools. In parallel, in the last few years there have been significant advances in the field of extracellular vesicles research. Among these vesicles, exosomes of endocytic origin, with a characteristic size ranging from 30-100 nm, carry several atypical secreted proteins in different organisms, including parasitic protozoa. Here, we present experimental evidence for the existence of exosome-like vesicles in parasitic helminths, specifically the trematodes Echinostoma caproni and Fasciola hepatica. These microvesicles are actively released by the parasites and are taken up by host cells. Trematode extracellular vesicles contain most of the proteins previously identified as components of ESP, as confirmed by proteomic, immunogold labeling and electron microscopy studies. In addition to parasitic proteins, we also identify host proteins in these structures. The existence of extracellular vesicles explains the secretion of atypical proteins in trematodes, and the demonstration of their uptake by host cells suggests an important role for these structures in host-parasite communication, as described for other infectious agents.

  9. Genetic variation and host-parasite specificity of Striga resistance and tolerance in rice: the need for predictive breeding.

    Science.gov (United States)

    Rodenburg, Jonne; Cissoko, Mamadou; Kayongo, Nicholas; Dieng, Ibnou; Bisikwa, Jenipher; Irakiza, Runyambo; Masoka, Isaac; Midega, Charles A O; Scholes, Julie D

    2017-05-01

    The parasitic weeds Striga asiatica and Striga hermonthica cause devastating yield losses to upland rice in Africa. Little is known about genetic variation in host resistance and tolerance across rice genotypes, in relation to virulence differences across Striga species and ecotypes. Diverse rice genotypes were phenotyped for the above traits in S. asiatica- (Tanzania) and S. hermonthica-infested fields (Kenya and Uganda) and under controlled conditions. New rice genotypes with either ecotype-specific or broad-spectrum resistance were identified. Resistance identified in the field was confirmed under controlled conditions, providing evidence that resistance was largely genetically determined. Striga-resistant genotypes contributed to yield security under Striga-infested conditions, although grain yield was also determined by the genotype-specific yield potential and tolerance. Tolerance, the physiological mechanism mitigating Striga effects on host growth and physiology, was unrelated to resistance, implying that any combination of high, medium or low levels of these traits can be found across rice genotypes. Striga virulence varies across species and ecotypes. The extent of Striga-induced host damage results from the interaction between parasite virulence and genetically determined levels of host-plant resistance and tolerance. These novel findings support the need for predictive breeding strategies based on knowledge of host resistance and parasite virulence. © 2017 The Authors. New Phytologist © 2017 New Phytologist Trust.

  10. The Bacteriome of Bat Flies (Nycteribiidae) from the Malagasy Region: a Community Shaped by Host Ecology, Bacterial Transmission Mode, and Host-Vector Specificity.

    Science.gov (United States)

    Wilkinson, David A; Duron, Olivier; Cordonin, Colette; Gomard, Yann; Ramasindrazana, Beza; Mavingui, Patrick; Goodman, Steven M; Tortosa, Pablo

    2016-01-08

    The Nycteribiidae are obligate blood-sucking Diptera (Hippoboscoidea) flies that parasitize bats. Depending on species, these wingless flies exhibit either high specialism or generalism toward their hosts, which may in turn have important consequences in terms of their associated microbial community structure. Bats have been hypothesized to be reservoirs of numerous infectious agents, some of which have recently emerged in human populations. Thus, bat flies may be important in the epidemiology and transmission of some of these bat-borne infectious diseases, acting either directly as arthropod vectors or indirectly by shaping pathogen communities among bat populations. In addition, bat flies commonly have associations with heritable bacterial endosymbionts that inhabit insect cells and depend on maternal transmission through egg cytoplasm to ensure their transmission. Some of these heritable bacteria are likely obligate mutualists required to support bat fly development, but others are facultative symbionts with unknown effects. Here, we present bacterial community profiles that were obtained from seven bat fly species, representing five genera, parasitizing bats from the Malagasy region. The observed bacterial diversity includes Rickettsia, Wolbachia, and several Arsenophonus-like organisms, as well as other members of the Enterobacteriales and a widespread association of Bartonella bacteria from bat flies of all five genera. Using the well-described host specificity of these flies and data on community structure from selected bacterial taxa with either vertical or horizontal transmission, we show that host/vector specificity and transmission mode are important drivers of bacterial community structure. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  11. Shigella Manipulates Host Immune Responses by Delivering Effector Proteins with Specific Roles

    Science.gov (United States)

    Ashida, Hiroshi; Mimuro, Hitomi; Sasakawa, Chihiro

    2015-01-01

    The intestinal epithelium deploys multiple defense systems against microbial infection to sense bacterial components and danger alarms, as well as to induce intracellular signal transduction cascades that trigger both the innate and the adaptive immune systems, which are pivotal for bacterial elimination. However, many enteric bacterial pathogens, including Shigella, deliver a subset of virulence proteins (effectors) via the type III secretion system (T3SS) that enable bacterial evasion from host immune systems; consequently, these pathogens are able to efficiently colonize the intestinal epithelium. In this review, we present and select recently discovered examples of interactions between Shigella and host immune responses, with particular emphasis on strategies that bacteria use to manipulate inflammatory outputs of host-cell responses such as cell death, membrane trafficking, and innate and adaptive immune responses. PMID:25999954

  12. Shigella manipulates host immune responses by delivering effector proteins with specific roles

    Directory of Open Access Journals (Sweden)

    Hiroshi eAshida

    2015-05-01

    Full Text Available The intestinal epithelium deploys multiple defense systems against microbial infection to sense bacterial components and danger alarms, as well as to induce intracellular signal transduction cascades that trigger both the innate and adaptive immune system, which are pivotal for bacterial elimination. However, many enteric bacterial pathogens, including Shigella, deliver a subset of virulence proteins (effectors via the type III secretion system (T3SS that enable bacterial evasion from host immune systems; consequently, these pathogens are able to efficiently colonize the intestinal epithelium. In this review, we present select recently discovered examples of interactions between Shigella and host immune responses, with particular emphasis on strategies that bacteria use to manipulate inflammatory outputs of host cell responses such as cell death, membrane trafficking, and innate and adaptive immune responses.

  13. Metabolomic Profiling of Bradyrhizobium diazoefficiens-Induced Root Nodules Reveals Both Host Plant-Specific and Developmental Signatures

    Directory of Open Access Journals (Sweden)

    Martina Lardi

    2016-05-01

    Full Text Available Bradyrhizobium diazoefficiens is a nitrogen-fixing endosymbiont, which can grow inside root-nodule cells of the agriculturally important soybean and other host plants. Our previous studies described B. diazoefficiens host-specific global expression changes occurring during legume infection at the transcript and protein level. In order to further characterize nodule metabolism, we here determine by flow injection–time-of-flight mass spectrometry analysis the metabolome of (i nodules and roots from four different B. diazoefficiens host plants; (ii soybean nodules harvested at different time points during nodule development; and (iii soybean nodules infected by two strains mutated in key genes for nitrogen fixation, respectively. Ribose (soybean, tartaric acid (mungbean, hydroxybutanoyloxybutanoate (siratro and catechol (cowpea were among the metabolites found to be specifically elevated in one of the respective host plants. While the level of C4-dicarboxylic acids decreased during soybean nodule development, we observed an accumulation of trehalose-phosphate at 21 days post infection (dpi. Moreover, nodules from non-nitrogen-fixing bacteroids (nifA and nifH mutants showed specific metabolic alterations; these were also supported by independent transcriptomics data. The alterations included signs of nitrogen limitation in both mutants, and an increased level of a phytoalexin in nodules induced by the nifA mutant, suggesting that the tissue of these nodules exhibits defense and stress reactions.

  14. Mesoniviruses are mosquito-specific viruses with extensive geographic distribution and host range

    Science.gov (United States)

    2014-01-01

    Background The family Mesoniviridae (order Nidovirales) comprises of a group of positive-sense, single-stranded RNA ([+]ssRNA) viruses isolated from mosquitoes. Findings Thirteen novel insect-specific virus isolates were obtained from mosquitoes collected in Indonesia, Thailand and the USA. By electron microscopy, the virions appeared as spherical particles with a diameter of ~50 nm. Their 20,129 nt to 20,777 nt genomes consist of positive-sense, single-stranded RNA with a poly-A tail. Four isolates from Houston, Texas, and one isolate from Java, Indonesia, were identified as variants of the species Alphamesonivirus-1 which also includes Nam Dinh virus (NDiV) from Vietnam and Cavally virus (CavV) from Côte d’Ivoire. The eight other isolates were identified as variants of three new mesoniviruses, based on genome organization and pairwise evolutionary distances: Karang Sari virus (KSaV) from Java, Bontag Baru virus (BBaV) from Java and Kalimantan, and Kamphaeng Phet virus (KPhV) from Thailand. In comparison with NDiV, the three new mesoniviruses each contained a long insertion (180 – 588 nt) of unknown function in the 5’ region of ORF1a, which accounted for much of the difference in genome size. The insertions contained various short imperfect repeats and may have arisen by recombination or sequence duplication. Conclusions In summary, based on their genome organizations and phylogenetic relationships, thirteen new viruses were identified as members of the family Mesoniviridae, order Nidovirales. Species demarcation criteria employed previously for mesoniviruses would place five of these isolates in the same species as NDiV and CavV (Alphamesonivirus-1) and the other eight isolates would represent three new mesonivirus species (Alphamesonivirus-5, Alphamesonivirus-6 and Alphamesonivirus-7). The observed spatiotemporal distribution over widespread geographic regions and broad species host range in mosquitoes suggests that mesoniviruses may be common in

  15. COI and ITS2 sequences delimit species, reveal cryptic taxa and host specificity of fig-associated Sycophila (Hymenoptera, Eurytomidae).

    Science.gov (United States)

    Li, Yanwei; Zhou, Xin; Feng, Gui; Hu, Haoyuan; Niu, Liming; Hebert, Paul D N; Huang, Dawei

    2010-01-01

    Although the genus Sycophila has broad host preferences, some species are specifically associated with figs as nonpollinator wasps. Because of their sexual dimorphism, morphological plasticity, cryptic mating behaviour and poorly known biology, species identifications are often uncertain. It is particularly difficult to match conspecific females and males. In this study, we employed two molecular markers, mitochondrial COI and nuclear ITS2, to identify Sycophila from six Chinese fig species. Morphological studies revealed 25 female and male morphs, while sequence results for both genes were consistent in supporting the presence of 15 species, of which 13 were host specialists and two used dual hosts. A single species of Sycophila was respectively found on four fig species, but six species were isolated from Ficus benjamina and a same number was reared from Ficus microcarpa. Sequence results revealed three male morphs in one species and detected two species that were overlooked by morphological analysis. © 2009 Blackwell Publishing Ltd.

  16. Host specificity and the structure of helminth parasite communities of fishes in a Neotropical river in Mexico

    Science.gov (United States)

    Salgado-Maldonado, Guillermo; Novelo-Turcotte, María Teresa; Caspeta-Mandujano, Juan Manuel; Vazquez-Hurtado, Gabriela; Quiroz-Martínez, Benjamin; Mercado-Silva, Norman; Favila, Mario

    2016-01-01

    In a tropical locality of Río La Antigua, Veracruz, Mexico, 11 fish species, represented by 244 individual fish from six freshwater fish families living sympatrically and synchronically, were examined for helminth parasites. A total of 36 taxa of helminths were recorded, 24 autogenic and 12 allogenic forms, including 6 monogeneans, 14 trematodes, 1 cestode, and 15 nematodes. Most helminth taxa were recovered for 10/11 of the component communities we analyzed. The results contribute empirical evidence that host specificity is an important force in the development of helminth communities of freshwater fishes. Each fish family has their own set of parasites, host species belonging to the same taxon share parasite species. High component community similarity among related host species was recorded, demonstrated by high prevalence and abundance, as well as dominance, of autogenic specialist species in each component community. Most autogenic helminth species are numerically and reproductively successful in relatively few host species. Autogenic helminths common in one host species are not common in others. Our findings give empirical support to the idea that low levels of sharing of parasites favor animal coexistence and high species richness, because large phylogenetic differences allow potentially competing animals to consume the same resources without being sensitive of another’s parasites. PMID:28004635

  17. Plant-feeding nematodes in coastal sand dunes: occurrence, host specificity and effects on plant growth

    NARCIS (Netherlands)

    Brinkman, E.P.; Duyts, Henk; Karssen, G.; Van der Stoel, C.D.; Van der Putten, Wim H.

    2015-01-01

    Aims Coastal sand dunes have a well-established abiotic gradient from beach to land and a corresponding spatial gradient of plant species representing succession in time. Here, we relate the distribution of plant-feeding nematodes with dominant plant species in the field to host specialization and

  18. Strictness Analysis and Denotational Abstract Interpretation

    DEFF Research Database (Denmark)

    Nielson, Flemming

    1988-01-01

    there and this sufices to make the framework applicable to strictness analysis for the lambda-calculus. This shows the possibility of a general theory for the analysis of functional programs and it gives more insight into the relative precision of the various analyses. In particular it is shown that a collecting (static......A theory of abstract interpretation () is developed for a typed lambda-calculus. The typed lambda-calculus may be viewed as the ''static'' part of a two-level denotational metalanguage for which abstract interpretation was developed by ). The present development relaxes a condition imposed...

  19. 7 CFR 28.441 - Strict Middling Yellow Stained Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Middling Yellow Stained Color. 28.441 Section... Strict Middling Yellow Stained Color. Strict Middling Yellow Stained Color is color which is deeper than that of Strict Middling Tinged Color. [57 FR 34498, Aug. 5, 1992] ...

  20. 7 CFR 28.412 - Strict Middling Light Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Middling Light Spotted Color. 28.412 Section 28... Light Spotted Color. Strict Middling Light Spotted Color is color which in spot or color, or both, is between Strict Middling Color and Strict Middling Spotted Color. ...

  1. Lineage-specific transcriptional profiles of Symbiodinium spp. unaltered by heat stress in a coral host.

    Science.gov (United States)

    Barshis, Daniel J; Ladner, Jason T; Oliver, Thomas A; Palumbi, Stephen R

    2014-06-01

    Dinoflagellates of the genus Symbiodinium form an endosymbiosis with reef building corals, in which photosynthetically derived nutrients comprise the majority of the coral energy budget. An extraordinary amount of functional and genetic diversity is contained within the coral-associated Symbiodinium, with some phylotypes (i.e., genotypic groupings), conferring enhanced stress tolerance to host corals. Recent advances in DNA sequencing technologies have enabled transcriptome-wide profiling of the stress response of the cnidarian coral host; however, a comprehensive understanding of the molecular response to stress of coral-associated Symbiodinium, as well as differences among physiologically susceptible and tolerant types, remains largely unexplored. Here, we examine the transcriptome-wide response to heat stress via RNA-Seq of two types of Symbiodinium, the putatively thermotolerant type D2 and the more susceptible type C3K, resident within the same coral host species, Acropora hyacinthus. Contrary to previous findings with coral hosts, we find no detectable change in gene expression across the dinoflagellate transcriptome after 3 days of elevated thermal exposure, despite physical evidence of symbiosis breakdown. However, hundreds of genes identified as orthologs between the C and D types exhibited significant expression differences within treatments (i.e., attributable solely to type, not heat exposure). These include many genes related to known thermotolerance mechanisms including heat shock proteins and chloroplast membrane components. Additionally, both the between-treatment similarities and between-type differences remained pervasive after 12-18 months of common garden acclimation and in mixed Symbiodinium assemblages within the same coral host colony. © The Author 2014. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  2. Staphylorchis cymatodes (Gorgoderidae: Anaporrhutinae) from carcharhiniform, orectolobiform and myliobatiform elasmobranchs of Australasia: low host specificity, wide distribution and morphological plasticity.

    Science.gov (United States)

    Cutmore, Scott C; Bennett, Michael B; Cribb, Thomas H

    2010-12-01

    Anaporrhutine gorgoderids (Digenea: Gorgoderidae: Anaporrhutinae) found in the body cavity of six species of elasmobranchs from the orders Carcharhiniformes, Myliobatiformes and Orectolobiformes from Australian waters were found to belong to the genus Staphylorchis. Although these specimens were morphologically variable, sequences of ITS2 and 28S ribosomal DNA from specimens from three host families and two host orders were identical. Based on morphological and molecular data these specimens were identified as the type-species of the genus, Staphylorchis cymatodes. New measurements are provided for S. cymatodes, and for the first time genetic data are presented for this species. In addition to providing new morphological and molecular data for S. cymatodes, the previously described species S. gigas, S. parisi and S. scoliodonii, are here synonymised with S. cymatodes. This implies that S. cymatodes, as conceived here, has remarkably low host-specificity, being recorded from eight elasmobranch species from four families and three orders, has a wide geographical distribution in the Indo-west Pacific from off India, in the Bay of Bengal, to Moreton Bay in the Coral Sea, and is morphologically plastic, with body size, size of specific organs and body shape differing dramatically between specimens from different host species. The genus Staphylorchis now contains only two valid species, S. cymatodes and S. pacifica. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  3. Specific allogeneic unresponsiveness in the adult host: present-day experimental models

    International Nuclear Information System (INIS)

    Rapaport, F.T.; Bachvaroff, R.J.; Cronkite, E.; Chanana, A.; Sato, T.; Asari, H.; Waltzer, W.C.

    1982-01-01

    As part of a long-term intensive effort to apply the induction of adult allogensic unresponsiveness to the transplantation problem, two techniques to control the variability in the persistence of immunologically competent postthymic cells iin the treated host and/or the inoculum of autologous marrow returned to the host after irradiation are described. The first consisted of exposing the peripheral blood of prospective recipients to a 5-week course of extra-corporeal irradiation (ECIB), the other of exposing the stored autologous marrow scheduled to repopulate a given recipient to methyl-prednisolone (MPd) and DNase prior to renifusion into the recipient. Serial analysis of bone marrow cell samples at various intervals before and after treatment was undertaken. The significance of the disappearance of a particular population of nonnuclear cells from the samples, and the association of such disappearance with increased success in the induction of allogeneic unresponsiveness is discussed

  4. Specific allogeneic unresponsiveness in the adult host: present-day experimental models

    Energy Technology Data Exchange (ETDEWEB)

    Rapaport, F.T.; Bachvaroff, R.J.; Cronkite, E.; Chanana, A.; Sato, T.; Asari, H.; Waltzer, W.C.

    1982-01-01

    As part of a long-term intensive effort to apply the induction of adult allogensic unresponsiveness to the transplantation problem, two techniques to control the variability in the persistence of immunologically competent postthymic cells iin the treated host and/or the inoculum of autologous marrow returned to the host after irradiation are described. The first consisted of exposing the peripheral blood of prospective recipients to a 5-week course of extra-corporeal irradiation (ECIB), the other of exposing the stored autologous marrow scheduled to repopulate a given recipient to methyl-prednisolone (MPd) and DNase prior to renifusion into the recipient. Serial analysis of bone marrow cell samples at various intervals before and after treatment was undertaken. The significance of the disappearance of a particular population of nonnuclear cells from the samples, and the association of such disappearance with increased success in the induction of allogeneic unresponsiveness is discussed. (ACR)

  5. Caribbean corals house shared and host-specific microbial symbionts over time and space.

    Science.gov (United States)

    Chu, Nathaniel D; Vollmer, Steven V

    2016-08-01

    The rise of coral diseases has triggered a surge of interest in coral microbial communities. But to fully understand how the coral microbiome may cause or respond to disease, we must first understand structure and variation in the healthy coral microbiome. We used 16S rRNA sequencing to characterize the microbiomes of 100 healthy coral colonies from six Caribbean coral species (Acropora cervicornis, A. palmata, Diploria labyrinthiformis, Diploria strigosa, Porites astreoides and P. furcata) across four reefs and three time points over 1 year. We found host species to be the strongest driver of coral microbiome structure across site and time. Analysis of the core microbiome revealed remarkable similarity in the bacterial taxa represented across coral hosts and many bacterial phylotypes shared across all corals sampled. Some of these widespread bacterial taxa have been identified in Pacific corals, indicating that a core coral microbiome may extend across oceans. Core bacterial phylotypes that were unique to each coral were taxonomically diverse, suggesting that different coral hosts provide persistent, divergent niches for bacteria. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Interplay of host specificity and biogeography in the population structure of a cosmopolitan endoparasite: microsatellite study of Ligula intestinalis (Cestoda)

    Czech Academy of Sciences Publication Activity Database

    Štefka, Jan; Hypša, Václav; Scholz, Tomáš

    2009-01-01

    Roč. 18, č. 6 (2009), s. 1187-1206 ISSN 0962-1083 R&D Projects: GA MŠk LC06073; GA ČR GA524/08/0885; GA MŠk LC522 Institutional research plan: CEZ:AV0Z60220518 Keywords : cryptic speciation * geographical isolation * host specificity * microsatellites * parasite * population structure Subject RIV: GJ - Animal Vermins ; Diseases, Veterinary Medicine Impact factor: 5.960, year: 2009

  7. A Carbohydrate Moiety of Secreted Stage-Specific Glycoprotein 4 Participates in Host Cell Invasion by Trypanosoma cruzi Extracellular Amastigotes

    Directory of Open Access Journals (Sweden)

    Pilar T. V. Florentino

    2018-04-01

    Full Text Available Trypanosoma cruzi is the etiologic agent of Chagas’ disease. It is known that amastigotes derived from trypomastigotes in the extracellular milieu are infective in vitro and in vivo. Extracellular amastigotes (EAs have a stage-specific surface antigen called Ssp-4, a GPI-anchored glycoprotein that is secreted by the parasites. By immunoprecipitation with the Ssp-4-specific monoclonal antibodies (mAb 2C2 and 1D9, we isolated the glycoprotein from EAs. By mass spectrometry, we identified the core protein of Ssp-4 and evaluated mRNA expression and the presence of Ssp-4 carbohydrate epitopes recognized by mAb1D9. We demonstrated that the carbohydrate epitope recognized by mAb1D9 could promote host cell invasion by EAs. Although infectious EAs express lower amounts of Ssp-4 compared with less-infectious EAs (at the mRNA and protein levels, it is the glycosylation of Ssp-4 (identified by mAb1D9 staining only in infectious strains and recognized by galectin-3 on host cells that is the determinant of EA invasion of host cells. Furthermore, Ssp-4 is secreted by EAs, either free or associated with parasite vesicles, and can participate in host-cell interactions. The results presented here describe the possible role of a carbohydrate moiety of T. cruzi surface glycoproteins in host cell invasion by EA forms, highlighting the potential of these moieties as therapeutic and vaccine targets for the treatment of Chagas’ disease.

  8. Low host specificity and abundance of frugivorous lepidoptera in the lowland rain forests of Papua New Guinea.

    Directory of Open Access Journals (Sweden)

    Katerina Sam

    Full Text Available We studied a community of frugivorous Lepidoptera in the lowland rainforest of Papua New Guinea. Rearing revealed 122 species represented by 1,720 individuals from 326 woody plant species. Only fruits from 52% (171 of the plant species sampled were attacked. On average, Lepidoptera were reared from 1 in 89 fruits and a kilogram of fruit was attacked by 1.01 individuals. Host specificity of Lepidoptera was notably low: 69% (33 of species attacked plants from >1 family, 8% (4 fed on single family, 6% (3 on single genus and 17% (8 were monophagous. The average kilogram of fruits was infested by 0.81 individual from generalist species (defined here as feeding on >1 plant genus and 0.07 individual from specialist species (feeding on a single host or congeneric hosts. Lepidoptera preferred smaller fruits with both smaller mesocarp and seeds. Large-seeded fruits with thin mesocarp tended to host specialist species whereas those with thick, fleshy mesocarp were often infested with both specialist and generalist species. The very low incidence of seed damage suggests that pre-dispersal seed predation by Lepidoptera does not play a major role in regulating plant populations via density-dependent mortality processes outlined by the Janzen-Connell hypothesis.

  9. Evaluation of the host specificity of Spathius galinae (Hymenoptera: Braconidae), a larval parasitoid of the emerald ash borer (Coleoptera: Buprestidae) in Northeast Asia

    Science.gov (United States)

    Host-specificity determination prior to the introduction of non-native natural enemies (predators and parasitoids) is a critical component of the risk assessment for modern classical biological control programs. In the present study, we assessed the host specificity of a newly described parasitoid,...

  10. Wolbachia age-sex-specific density in Aedes albopictus: a host evolutionary response to cytoplasmic incompatibility?

    Directory of Open Access Journals (Sweden)

    Pablo Tortosa

    2010-03-01

    Full Text Available Wolbachia bacteria have invaded many arthropod species by inducing Cytoplasmic Incompatibility (CI. These symbionts represent fascinating objects of study for evolutionary biologists, but also powerful potential biocontrol agents. Here, we assess the density dynamics of Wolbachia infections in males and females of the mosquito Aedes albopitcus, an important vector of human pathogens, and interpret the results within an evolutionary framework.Wolbachia densities were measured in natural populations and in age controlled mosquitoes using quantitative PCR. We show that the density dynamics of the wAlbA Wolbachia strain infecting Aedes albopictus drastically differ between males and females, with a very rapid decay of infection in males only.Theory predicts that Wolbachia and its hosts should cooperate to improve the transmission of infection to offspring, because only infected eggs are protected from the effects of CI. However, incompatible matings effectively lower the fertility of infected males, so that selection acting on the host genome should tend to reduce the expression of CI in males, for example, by reducing infection density in males before sexual maturation. The rapid decay of one Wolbachia infection in Aedes albopictus males, but not in females, is consistent with this prediction. We suggest that the commonly observed reduction in CI intensity with male age reflects a similar evolutionary process. Our results also highlight the importance of monitoring infection density dynamics in both males and females to assess the efficiency of Wolbachia-based control strategies.

  11. Isolation and characterization of Bacteroides host strain HB-73 used to detect sewage specific phages in Hawaii.

    Science.gov (United States)

    Vijayavel, Kannappan; Fujioka, Roger; Ebdon, James; Taylor, Huw

    2010-06-01

    Previous studies have shown that Escherichia coli and enterococci are unreliable indicators of fecal contamination in Hawaii because of their ability to multiply in environmental soils. In this study, the method of detecting Bacteroides phages as specific markers of sewage contamination in Hawaii's recreational waters was evaluated because these sewage specific phages cannot multiply under environmental conditions. Bacteroides hosts (GB-124, GA-17), were recovered from sewage samples in Europe and were reported to be effective in detecting phages from sewage samples obtained in certain geographical areas. However, GB-124 and GA-17 hosts were ineffective in detecting phages from sewage samples obtained in Hawaii. Bacteroides host HB-73 was isolated from a sewage sample in Hawaii, confirmed as a Bacteroides sp. and shown to recover phages from multiple sources of sewage produced in Hawaii at high concentrations (5.2-7.3 x 10(5) PFU/100 mL). These Bacteroides phages were considered as potential markers of sewage because they also survived for three days in fresh stream water and two days in marine water. Water samples from Hawaii's coastal swimming beaches and harbors, which were known to be contaminated with discharges from streams, were shown to contain moderate (20-187 CFU/100 mL) to elevated (173-816 CFU/100 mL) concentrations of enterococci. These same samples contained undetectable levels (Hawaii and the most likely source of these enterococci is from environmental soil rather than from sewage. 2010 Elsevier Ltd. All rights reserved.

  12. Survey of immunoglobulin A protease activity among selected species of Ureaplasma and Mycoplasma: specificity for host immunoglobulin A.

    Science.gov (United States)

    Kapatais-Zoumbos, K; Chandler, D K; Barile, M F

    1985-03-01

    Because immunoglobulin A (IgA) is the predominant immunoglobulin at mucosal surfaces, IgA proteases produced by pathogenic bacteria are considered potential virulence factors for organisms that cause disease or gain entry at mucous membranes. To determine the role of IgA protease in the pathogenicity of mycoplasmal disease, a variety of human and animal mycoplasma and ureaplasma species were examined for IgA protease activity with human, murine, porcine, and canine IgA. None of the mycoplasma species examined showed detectable IgA protease activity with any of the IgAs tested. Twenty-eight strains of Ureaplasma urealyticum isolated from human urogenital tissues cleaved human IgA1, but no cleavage of human IgA2 or murine, porcine, or canine IgA was observed. Ureaplasmas isolated from nonhuman hosts (feline, canine, avian, and bovine [Ureaplasma diversum]) did not cleave human IgA1. Two strains of canine ureaplasmas were able to cleave canine IgA, but not murine IgA. Thus, ureaplasmas from other species can produce IgA protease, but the specificity of the enzyme was restricted to the IgA of the appropriate host. This finding suggests that IgA proteases could play a role in the selective host specificity of mucosal pathogens.

  13. Genome-Wide Comparison of Magnaporthe Species Reveals a Host-Specific Pattern of Secretory Proteins and Transposable Elements.

    Directory of Open Access Journals (Sweden)

    Meghana Deepak Shirke

    Full Text Available Blast disease caused by the Magnaporthe species is a major factor affecting the productivity of rice, wheat and millets. This study was aimed at generating genomic information for rice and non-rice Magnaporthe isolates to understand the extent of genetic variation. We have sequenced the whole genome of the Magnaporthe isolates, infecting rice (leaf and neck, finger millet (leaf and neck, foxtail millet (leaf and buffel grass (leaf. Rice and finger millet isolates infecting both leaf and neck tissues were sequenced, since the damage and yield loss caused due to neck blast is much higher as compared to leaf blast. The genome-wide comparison was carried out to study the variability in gene content, candidate effectors, repeat element distribution, genes involved in carbohydrate metabolism and SNPs. The analysis of repeat element footprints revealed some genes such as naringenin, 2-oxoglutarate 3-dioxygenase being targeted by Pot2 and Occan, in isolates from different host species. Some repeat insertions were host-specific while other insertions were randomly shared between isolates. The distributions of repeat elements, secretory proteins, CAZymes and SNPs showed significant variation across host-specific lineages of Magnaporthe indicating an independent genome evolution orchestrated by multiple genomic factors.

  14. Increased sampling reveals novel lineages of Entamoeba: consequences of genetic diversity and host specificity for taxonomy and molecular detection.

    Science.gov (United States)

    Stensvold, C Rune; Lebbad, Marianne; Victory, Emma L; Verweij, Jaco J; Tannich, Egbert; Alfellani, Mohammed; Legarraga, Paulette; Clark, C Graham

    2011-07-01

    To expand the representation for phylogenetic analysis, ten additional complete Entamoeba small-subunit rRNA gene sequences were obtained from humans, non-human primates, cattle and a tortoise. For some novel sequences no corresponding morphological data were available, and we suggest that these organisms should be referred to as ribosomal lineages (RL) rather than being assigned species names at present. To investigate genetic diversity and host specificity of selected Entamoeba species, a total of 91 new partial small subunit rRNA gene sequences were obtained, including 49 from Entamoeba coli, 18 from Entamoeba polecki, and 17 from Entamoeba hartmanni. We propose a new nomenclature for significant variants within established Entamoeba species. Based on current data we propose that the uninucleated-cyst-producing Entamoeba infecting humans is called Entamoeba polecki and divided into four subtypes (ST1-ST4) and that Entamoeba coli is divided into two subtypes (ST1-ST2). New hosts for several species were detected and, while host specificity and genetic diversity of several species remain to be clarified, it is clear that previous reliance on cultivated material has given us a misleading and incomplete picture of variation within the genus Entamoeba. Copyright © 2010 Elsevier GmbH. All rights reserved.

  15. Host Glycan Sugar-Specific Pathways in Streptococcus pneumonia: Galactose as a Key Sugar in Colonisation and Infection

    Science.gov (United States)

    Paixão, Laura; Oliveira, Joana; Veríssimo, André; Vinga, Susana; Lourenço, Eva C.; Ventura, M. Rita; Kjos, Morten; Veening, Jan-Willem; Fernandes, Vitor E.; Andrew, Peter W.; Yesilkaya, Hasan; Neves, Ana Rute

    2015-01-01

    The human pathogen Streptococcus pneumoniae is a strictly fermentative organism that relies on glycolytic metabolism to obtain energy. In the human nasopharynx S. pneumoniae encounters glycoconjugates composed of a variety of monosaccharides, which can potentially be used as nutrients once depolymerized by glycosidases. Therefore, it is reasonable to hypothesise that the pneumococcus would rely on these glycan-derived sugars to grow. Here, we identified the sugar-specific catabolic pathways used by S. pneumoniae during growth on mucin. Transcriptome analysis of cells grown on mucin showed specific upregulation of genes likely to be involved in deglycosylation, transport and catabolism of galactose, mannose and N acetylglucosamine. In contrast to growth on mannose and N-acetylglucosamine, S. pneumoniae grown on galactose re-route their metabolic pathway from homolactic fermentation to a truly mixed acid fermentation regime. By measuring intracellular metabolites, enzymatic activities and mutant analysis, we provide an accurate map of the biochemical pathways for galactose, mannose and N-acetylglucosamine catabolism in S. pneumoniae. Intranasal mouse infection models of pneumococcal colonisation and disease showed that only mutants in galactose catabolic genes were attenuated. Our data pinpoint galactose as a key nutrient for growth in the respiratory tract and highlights the importance of central carbon metabolism for pneumococcal pathogenesis. PMID:25826206

  16. Mitochondrial COI and morphological specificity of the mealy aphids (Hyalopterus ssp. collected from different hosts in Europe (Hemiptera, Aphididae

    Directory of Open Access Journals (Sweden)

    Rimantas Rakauskas

    2013-07-01

    Full Text Available Forty three European population samples of mealy aphids from various winter and summer host plants were attributed to respective species of Hyalopterus by means of their partial sequences of mitochondrial COI gene. Used Hyalopterus samples emerged as monophyletic relative to outgroup and formed three major clades representing three host specific mealy aphid species in the Neighbor joining, Maximum parsimony, Maximum likelihood and Bayesian inference trees. H. pruni and H. persikonus emerged as a sister species, whilst H. amygdali was located basally. Samples representing different clades in the molecular trees were used for canonical discrimination analysis based on twenty two morphological characters. Length of the median dorsal head hair enabled a 97.3 % separation of H. amygdali from the remaining two species. No single character enabled satisfactory discrimination between apterous viviparous females of H. pruni and H. persikonus. A modified key for the morphological identification of Hyalopterus species is suggested and their taxonomic status discussed.

  17. Molecular characterization of Babesia peircei and Babesia ugwidiensis provides insight into the evolution and host specificity of avian piroplasmids

    Directory of Open Access Journals (Sweden)

    Michael J. Yabsley

    2017-12-01

    Full Text Available There are 16 recognized species of avian-infecting Babesia spp. (Piroplasmida: Babesiidae. While the classification of piroplasmids has been historically based on morphological differences, geographic isolation and presumed host and/or vector specificities, recent studies employing gene sequence analysis have provided insight into their phylogenetic relationships and host distribution and specificity. In this study, we analyzed the sequences of the 18S rRNA gene and ITS-1 and ITS-2 regions of two Babesia species from South African seabirds: Babesia peircei from African penguins (Spheniscus demersus and Babesia ugwidiensis from Bank and Cape cormorants (Phalacrocorax neglectus and P. capensis, respectively. Our results show that avian Babesia spp. are not monophyletic, with at least three distinct phylogenetic groups. B. peircei and B. ugwidiensis are closely related, and fall within the same phylogenetic group as B. ardeae (from herons Ardea cinerea, B. poelea (from boobies Sula spp. and B. uriae (from murres Uria aalge. The validity of B. peircei and B. ugwidiensis as separate species is corroborated by both morphological and genetic evidence. On the other hand, our results indicate that B. poelea might be a synonym of B. peircei, which in turn would be a host generalist that infects seabirds from multiple orders. Further studies combining morphological and molecular methods are warranted to clarify the taxonomy, phylogeny and host distribution of avian piroplasmids. Keywords: Africa, Babesia, Piroplasmida, Phalacrocoracidae, Spheniscidae, Tick-borne pathogen

  18. Geometrical optimization for strictly localized structures

    Science.gov (United States)

    Mo, Yirong

    2003-07-01

    Recently we proposed the block localized wavefunction (BLW) approach which takes the advantages of valence bond theory and molecular orbital theory and defines the wavefunctions for resonance structures based on the assumption that all electrons and orbitals are partitioned into a few subgroups. In this work, we implement the geometrical optimization of the BLW method based on the algorithm proposed by Gianinetti and coworkers. Thus, we can study the conjugation effect on not only the molecular stability, but also the molecular geometry. With this capability, the π conjugation effect in trans-polyenes C2nH2n+2 (n=2-5) as well as in formamide and its analogs are studied by optimizing their delocalized and strictly localized forms with the 6-31G(d) and 6-311+G(d,p) basis sets. Although it has been well presumed that the π resonance shortens the single bonds and lengthens the double bonds with the delocalization of π electrons across the whole line in polyenes, our optimization of the strictly localized structures quantitatively shows that when the conjugation effect is "turned off," the double bond lengths will be identical to the CC bond length in ethylene and the single Csp2-Csp2 bond length will be about 1.513-1.517 Å. In agreement with the classical Hückel theory, the resonance energies in polyenes are approximately in proportion to the number of double bonds. Similarly, resonance is responsible not only for the planarity of formamide, thioformamide, and selenoformamide, but also for the lengthening of the CX (X=O,S,Se) double bond and the shortening of the CN bonds. Although it is assumed that the CX bond polarization decreases in the order of O>S>Se, the π electronic delocalization increases in the opposite order, i.e., formamide

  19. From Regular to Strictly Locally Testable Languages

    Directory of Open Access Journals (Sweden)

    Stefano Crespi Reghizzi

    2011-08-01

    Full Text Available A classical result (often credited to Y. Medvedev states that every language recognized by a finite automaton is the homomorphic image of a local language, over a much larger so-called local alphabet, namely the alphabet of the edges of the transition graph. Local languages are characterized by the value k=2 of the sliding window width in the McNaughton and Papert's infinite hierarchy of strictly locally testable languages (k-slt. We generalize Medvedev's result in a new direction, studying the relationship between the width and the alphabetic ratio telling how much larger the local alphabet is. We prove that every regular language is the image of a k-slt language on an alphabet of doubled size, where the width logarithmically depends on the automaton size, and we exhibit regular languages for which any smaller alphabetic ratio is insufficient. More generally, we express the trade-off between alphabetic ratio and width as a mathematical relation derived from a careful encoding of the states. At last we mention some directions for theoretical development and application.

  20. Bartonella entry mechanisms into mammalian host cells.

    Science.gov (United States)

    Eicher, Simone C; Dehio, Christoph

    2012-08-01

    The Gram-negative genus Bartonella comprises arthropod-borne pathogens that typically infect mammals in a host-specific manner. Bartonella bacilliformis and Bartonella quintana are human-specific pathogens, while several zoonotic bartonellae specific for diverse animal hosts infect humans as an incidental host. Clinical manifestations of Bartonella infections range from mild symptoms to life-threatening disease. Following transmission by blood-sucking arthropods or traumatic contact with infected animals, bartonellae display sequential tropisms towards endothelial and possibly other nucleated cells and erythrocytes, the latter in a host-specific manner. Attachment to the extracellular matrix (ECM) and to nucleated cells is mediated by surface-exposed bacterial adhesins, in particular trimeric autotransporter adhesins (TAAs). The subsequent engulfment of the pathogen into a vacuolar structure follows a unique series of events whereby the pathogen avoids the endolysosomal compartments. For Bartonella henselae and assumingly most other species, the infection process is aided at different steps by Bartonella effector proteins (Beps). They are injected into host cells through the type IV secretion system (T4SS) VirB/D4 and subvert host cellular functions to favour pathogen uptake. Bacterial binding to erythrocytes is mediated by Trw, another T4SS, in a strictly host-specific manner, followed by pathogen-forced uptake involving the IalB invasin and subsequent replication and persistence within a membrane-bound intra-erythrocytic compartment. © 2012 Blackwell Publishing Ltd.

  1. Pathogen specific T-lymphocytes for the reconstitution of the immunocompromised host.

    Science.gov (United States)

    Li Pira, Giuseppina; Kapp, Markus; Manca, Fabrizio; Einsele, Hermann

    2009-10-01

    Cellular immune functions are impaired in hemopoietic stem cell and solid organ transplantation or in cancer and autoimmune diseases treated with intensified immunosuppression. Thus, control of opportunistic pathogens is lost and severe infections break out. Defective cellular immunity can be restored upon endogenous immunoreconstitution or, if delayed, exogenous immunoreconstitution with pathogen specific T-lymphocytes selected or expanded from appropriate donors can be applied. Here we describe how recent developments in basic immunology knowledge and techniques have accelerated progresses of clinical trials in this attractive field. In particular, methods for the identification of appropriate antigens, for selection and expansion of specific T-cells and for safer manipulation of cellular products have been applied with promising advances. Finally, the development of biobanks of specific T-cells is described as an attractive perspective to reconstruct pathogen specific cellular immunity.

  2. 7 CFR 28.404 - Strict Low Middling Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Low Middling Color. 28.404 Section 28.404... for the Color Grade of American Upland Cotton § 28.404 Strict Low Middling Color. Strict Low Middling Color is color which is within the range represented by a set of samples in the custody of the United...

  3. 7 CFR 28.406 - Strict Good Ordinary Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Good Ordinary Color. 28.406 Section 28.406... for the Color Grade of American Upland Cotton § 28.406 Strict Good Ordinary Color. Strict Good Ordinary Color is color which is within the range represented by a set of samples in the custody of the...

  4. 7 CFR 28.402 - Strict Middling Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Middling Color. 28.402 Section 28.402... for the Color Grade of American Upland Cotton § 28.402 Strict Middling Color. Strict Middling Color is color which is within the range represented by a set of samples in the custody of the United States...

  5. Shared and host-specific microbiome diversity and functioning of grapevine and accompanying weed plants.

    Science.gov (United States)

    Samad, Abdul; Trognitz, Friederike; Compant, Stéphane; Antonielli, Livio; Sessitsch, Angela

    2017-04-01

    Weeds and crop plants select their microbiota from the same pool of soil microorganisms, however, the ecology of weed microbiomes is poorly understood. We analysed the microbiomes associated with roots and rhizospheres of grapevine and four weed species (Lamium amplexicaule L., Veronica arvensis L., Lepidium draba L. and Stellaria media L.) growing in proximity in the same vineyard using 16S rRNA gene sequencing. We also isolated and characterized 500 rhizobacteria and root endophytes from L. draba and grapevine. Microbiome data analysis revealed that all plants hosted significantly different microbiomes in the rhizosphere as well as in root compartment, however, differences were more pronounced in the root compartment. The shared microbiome of grapevine and the four weed species contained 145 OTUs (54.2%) in the rhizosphere, but only nine OTUs (13.2%) in the root compartment. Seven OTUs (12.3%) were shared in all plants and compartments. Approximately 56% of the major OTUs (>1%) showed more than 98% identity to bacteria isolated in this study. Moreover, weed-associated bacteria generally showed a higher species richness in the rhizosphere, whereas the root-associated bacteria were more diverse in the perennial plants grapevine and L. draba. Overall, weed isolates showed more plant growth-promoting characteristics compared with grapevine isolates. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  6. Diversity and host specificity of coccidia (Apicomplexa: Eimeriidae) in native and introduced squirrel species.

    Science.gov (United States)

    Hofmannová, Lada; Romeo, Claudia; Štohanzlová, Lucie; Jirsová, Dagmar; Mazzamuto, Maria Vittoria; Wauters, Lucas Armand; Ferrari, Nicola; Modrý, David

    2016-10-01

    Introduction of alien species into new areas can have detrimental effects on native ecosystems and impact the native species. The present study aims to identify coccidia infecting native and introduced squirrels in Italy, to gain insight into possible transmission patterns and role of monoxenous coccidia in mediating the competition between alien and native hosts. We collected 540 faecal samples of native red squirrels, Sciurus vulgaris, invasive alien grey squirrels, S. carolinensis, and introduced Pallas's squirrels, Callosciurus erythraeus. Total prevalence of Eimeria spp. was 95.6% in S. vulgaris, 95.7% in S. carolinensis and only 4.1% in C. erythraeus. Morphological examination revealed 3 Eimeria morphotypes. Phylogenetic analyses of Eimeria DNA based on 18S, ITS, cox I markers displayed fairly distinct monophyletic clades in the microscopically indistinguishable E2 morphotype, proving indisputable distinction between the isolates from red and grey squirrels. Grey squirrels successfully introduced E. lancasterensis from their native range, but this species does not spill over to native red squirrels. Similarly, there is no evidence for the transmission of E. sciurorum from red to grey squirrels. The possible transmission and the potential role of monoxenous coccidia in mediating the competition between native and invasive squirrels in Italy were not confirmed. Copyright © 2016 Elsevier GmbH. All rights reserved.

  7. Sialylation of Glycosylphosphatidylinositol (GPI) Anchors of Mammalian Prions Is Regulated in a Host-, Tissue-, and Cell-specific Manner*

    Science.gov (United States)

    Katorcha, Elizaveta; Srivastava, Saurabh; Klimova, Nina; Baskakov, Ilia V.

    2016-01-01

    Prions or PrPSc are proteinaceous infectious agents that consist of misfolded, self-replicating states of the prion protein or PrPC. PrPC is posttranslationally modified with N-linked glycans and a sialylated glycosylphosphatidylinositol (GPI) anchor. Conformational conversion of PrPC gives rise to glycosylated and GPI-anchored PrPSc. The question of the sialylation status of GPIs within PrPSc has been controversial. Previous studies that examined scrapie brains reported that both sialo- and asialo-GPIs were present in PrPSc, with the majority being asialo-GPIs. In contrast, recent work that employed cultured cells claimed that only PrPC with sialylo-GPIs could be recruited into PrPSc, whereas PrPC with asialo-GPIs inhibited conversion. To resolve this controversy, we analyzed the sialylation status of GPIs within PrPSc generated in the brain, spleen, or cultured N2a or C2C12 myotube cells. We found that recruiting PrPC with both sialo- and asialo-GPIs is a common feature of PrPSc. The mixtures of sialo- and asialo-GPIs were observed in PrPSc universally regardless of prion strain as well as host, tissue, or type of cells that produced PrPSc. Remarkably, the proportion of sialo- versus asialo-GPIs was found to be controlled by host, tissue, and cell type but not prion strain. In summary, this study found no strain-specific preferences for selecting PrPC with sialo- versus asialo-GPIs. Instead, this work suggests that the sialylation status of GPIs within PrPSc is regulated in a cell-, tissue-, or host-specific manner and is likely to be determined by the specifics of GPI biosynthesis. PMID:27317661

  8. Specific chlamydial inclusion membrane proteins associate with active Src family kinases in microdomains that interact with the host microtubule network.

    Science.gov (United States)

    Mital, Jeffrey; Miller, Natalie J; Fischer, Elizabeth R; Hackstadt, Ted

    2010-09-01

    Chlamydiae are Gram-negative obligate intracellular bacteria that cause diseases with significant medical and economic impact. Chlamydia trachomatis replicates within a vacuole termed an inclusion, which is extensively modified by the insertion of a number of bacterial effector proteins known as inclusion membrane proteins (Incs). Once modified, the inclusion is trafficked in a dynein-dependent manner to the microtubule-organizing centre (MTOC), where it associates with host centrosomes. Here we describe a novel structure on the inclusion membrane comprised of both host and bacterial proteins. Members of the Src family of kinases are recruited to the chlamydial inclusion in an active form. These kinases display a distinct, localized punctate microdomain-like staining pattern on the inclusion membrane that colocalizes with four chlamydial inclusion membrane proteins (Incs) and is enriched in cholesterol. Biochemical studies show that at least two of these Incs stably interact with one another. Furthermore, host centrosomes associate with these microdomain proteins in C. trachomatis-infected cells and in uninfected cells exogenously expressing one of the chlamydial effectors. Together, the data suggest that a specific structure on the C. trachomatis inclusion membrane may be responsible for the known interactions of chlamydiae with the microtubule network and resultant effects on centrosome stability.

  9. Ecology and host specificity of laelapine mites (Acari: Laelapidae) of small mammals in an Atlantic forest area of Brazil.

    Science.gov (United States)

    Martins-Hatano, Fernanda; Gettinger, Donald; Bergallo, Helena G

    2002-02-01

    Mesostigmatic mites of the Laelapinae Berlese, 1892 (Acari: Laelapidae) are nidicolous arthropods that commonly occur in the fur of Neotropical small mammmals. In this 2-yr study, the laelapine acarofauna associated with the small mammal community in an area of Atlantic forest on Ilha Grande, Rio de Janeiro State, was examined, including observations on patterns of host specificity, mite dispersal, ecology, and food habits. A total of 1,347 laelapines was sampled from the pelage of 6 species of small mammals (Marmosops incanus, Nectomys squamipes, Oryzomys russatus, Rhipidomys n. sp., Oxymycterus dasytrichus, and Trinomys dimidiatus), all of which occurred exclusively in monoxenous associations with their hosts. No evidence of a blood meal was observed in the gut of the mites. With the exception of the 2 species of Tur, mite populations on hosts were entirely or nearly restricted to adult females. These results, together with some morphological characteristics of laelapines, reinforce the hypotheses that Neotropical laelapine mites are not ectoparasitic, and that females disperse by phoresy.

  10. Bacteriophages with potential for inactivation of fish pathogenic bacteria: survival, host specificity and effect on bacterial community structure.

    Science.gov (United States)

    Pereira, Carla; Silva, Yolanda J; Santos, Ana L; Cunha, Angela; Gomes, Newton C M; Almeida, Adelaide

    2011-01-01

    Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential to inactivate fish pathogenic bacteria, without major effects on the structure of natural bacterial communities of aquaculture waters. The survival was determined in marine water, through quantification by the soft agar overlay technique. The host specificity was evaluated by cross infection. The ecological impact of phage addition on the structure of the bacterial community was evaluated by DGGE of PCR amplified 16S rRNA gene fragments. The survival period varied between 12 and 91 days, with a higher viability for Aeromonas salmonicida phages. The phages of Vibrio parahaemolyticus and of A. salmonicida infected bacteria of different families with a high efficacy of plating. The specific phages of pathogenic bacteria had no detectable impact on the structure of the bacterial community. In conclusion, V. parahaemolyticus and A. salmonicida phages show good survival time in marine water, have only a moderated impact on the overall bacterial community structure and the desired specificity for host pathogenic bacteria, being potential candidates for therapy of fish infectious diseases in marine aquaculture systems.

  11. Bacteriophages with Potential for Inactivation of Fish Pathogenic Bacteria: Survival, Host Specificity and Effect on Bacterial Community Structure

    Directory of Open Access Journals (Sweden)

    Yolanda J. Silva

    2011-11-01

    Full Text Available Phage therapy may represent a viable alternative to antibiotics to inactivate fish pathogenic bacteria. Its use, however, requires the awareness of novel kinetics phenomena not applied to conventional drug treatments. The main objective of this work was to isolate bacteriophages with potential to inactivate fish pathogenic bacteria, without major effects on the structure of natural bacterial communities of aquaculture waters. The survival was determined in marine water, through quantification by the soft agar overlay technique. The host specificity was evaluated by cross infection. The ecological impact of phage addition on the structure of the bacterial community was evaluated by DGGE of PCR amplified 16S rRNA gene fragments. The survival period varied between 12 and 91 days, with a higher viability for Aeromonas salmonicida phages. The phages of Vibrio parahaemolyticus and of A. salmonicida infected bacteria of different families with a high efficacy of plating. The specific phages of pathogenic bacteria had no detectable impact on the structure of the bacterial community. In conclusion, V. parahaemolyticus and A. salmonicida phages show good survival time in marine water, have only a moderated impact on the overall bacterial community structure and the desired specificity for host pathogenic bacteria, being potential candidates for therapy of fish infectious diseases in marine aquaculture systems.

  12. Host specificity of ambrosia and bark beetles (Col., Curculionidae: Scolytinae and Platypodinae) in a New Guinea rainforest

    Czech Academy of Sciences Publication Activity Database

    Hulcr, Jiří; Mogia, M.; Isua, B.; Novotný, Vojtěch

    2007-01-01

    Roč. 32, č. 6 (2007), s. 762-772 ISSN 0307-6946 R&D Projects: GA ČR GD206/03/H034 Grant - others:University of South Bohemia(CZ) 57/2004/P-B; National Science Foundation(US) DEB 02-11591; National Science Foundation(US) PEET DEB-0328920 Institutional research plan: CEZ:AV0Z50070508 Source of funding: V - iné verejné zdroje ; O - operačné programy ; O - operačné programy Keywords : host specificity * Mycetophagy * Mycophagy Subject RIV: EH - Ecology, Behaviour Impact factor: 1.741, year: 2007

  13. Host Ranges of Listeria-Specific Bacteriophages from the Turkey Processing Plant Environment in the United States ▿

    Science.gov (United States)

    Kim, Jae-Won; Siletzky, Robin M.; Kathariou, Sophia

    2008-01-01

    Even though at least 400 Listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. Phages in the processing plant environment may play critical roles in determining the Listeria population that becomes established in the plant. In this study, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey processing plants in the United States. These environmental samples were also utilized to isolate Listeria spp. Twelve phages were isolated and classified into three groups in terms of their host range. Of these, nine (group 1) showed a wide host range, including multiple serotypes of Listeria monocytogenes, as well as other Listeria spp. (L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii). The remaining phages mostly infected L. monocytogenes serotype 4b as well as L. innocua, L. ivanovii, and/or L. welshimeri. All but one of the strains of the serotype 4b complex (4b, 4d, 4e) from the processing plant environment could be readily infected by the wide-host-range phages isolated from the environment of the processing plants. However, many strains of other serotypes (1/2a [or 3a] and 1/2b [or 3b]), which represented the majority of L. monocytogenes strains isolated from the environmental samples, were resistant to infection by these phages. Experiments with two phage-resistant strains showed reduced phage adsorption onto the host cells. These findings suggest that phage resistance may be an important component of the ecology of L. monocytogenes in the turkey processing plants. PMID:18791016

  14. Host ranges of Listeria-specific bacteriophages from the turkey processing plant environment in the United States.

    Science.gov (United States)

    Kim, Jae-Won; Siletzky, Robin M; Kathariou, Sophia

    2008-11-01

    Even though at least 400 Listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. Phages in the processing plant environment may play critical roles in determining the Listeria population that becomes established in the plant. In this study, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey processing plants in the United States. These environmental samples were also utilized to isolate Listeria spp. Twelve phages were isolated and classified into three groups in terms of their host range. Of these, nine (group 1) showed a wide host range, including multiple serotypes of Listeria monocytogenes, as well as other Listeria spp. (L. innocua, L. welshimeri, L. seeligeri, and L. ivanovii). The remaining phages mostly infected L. monocytogenes serotype 4b as well as L. innocua, L. ivanovii, and/or L. welshimeri. All but one of the strains of the serotype 4b complex (4b, 4d, 4e) from the processing plant environment could be readily infected by the wide-host-range phages isolated from the environment of the processing plants. However, many strains of other serotypes (1/2a [or 3a] and 1/2b [or 3b]), which represented the majority of L. monocytogenes strains isolated from the environmental samples, were resistant to infection by these phages. Experiments with two phage-resistant strains showed reduced phage adsorption onto the host cells. These findings suggest that phage resistance may be an important component of the ecology of L. monocytogenes in the turkey processing plants.

  15. Mammalian evolution may not be strictly bifurcating.

    Science.gov (United States)

    Hallström, Björn M; Janke, Axel

    2010-12-01

    The massive amount of genomic sequence data that is now available for analyzing evolutionary relationships among 31 placental mammals reduces the stochastic error in phylogenetic analyses to virtually zero. One would expect that this would make it possible to finally resolve controversial branches in the placental mammalian tree. We analyzed a 2,863,797 nucleotide-long alignment (3,364 genes) from 31 placental mammals for reconstructing their evolution. Most placental mammalian relationships were resolved, and a consensus of their evolution is emerging. However, certain branches remain difficult or virtually impossible to resolve. These branches are characterized by short divergence times in the order of 1-4 million years. Computer simulations based on parameters from the real data show that as little as about 12,500 amino acid sites could be sufficient to confidently resolve short branches as old as about 90 million years ago (Ma). Thus, the amount of sequence data should no longer be a limiting factor in resolving the relationships among placental mammals. The timing of the early radiation of placental mammals coincides with a period of climate warming some 100-80 Ma and with continental fragmentation. These global processes may have triggered the rapid diversification of placental mammals. However, the rapid radiations of certain mammalian groups complicate phylogenetic analyses, possibly due to incomplete lineage sorting and introgression. These speciation-related processes led to a mosaic genome and conflicting phylogenetic signals. Split network methods are ideal for visualizing these problematic branches and can therefore depict data conflict and possibly the true evolutionary history better than strictly bifurcating trees. Given the timing of tectonics, of placental mammalian divergences, and the fossil record, a Laurasian rather than Gondwanan origin of placental mammals seems the most parsimonious explanation.

  16. Rhinovirus 3C protease facilitates specific nucleoporin cleavage and mislocalisation of nuclear proteins in infected host cells.

    Directory of Open Access Journals (Sweden)

    Erin J Walker

    Full Text Available Human Rhinovirus (HRV infection results in shut down of essential cellular processes, in part through disruption of nucleocytoplasmic transport by cleavage of the nucleoporin proteins (Nups that make up the host cell nuclear pore. Although the HRV genome encodes two proteases (2A and 3C able to cleave host proteins such as Nup62, little is known regarding the specific contribution of each. Here we use transfected as well as HRV-infected cells to establish for the first time that 3C protease is most likely the mediator of cleavage of Nup153 during HRV infection, while Nup62 and Nup98 are likely to be targets of HRV2A protease. HRV16 3C protease was also able to elicit changes in the appearance and distribution of the nuclear speckle protein SC35 in transfected cells, implicating it as a key mediator of the mislocalisation of SC35 in HRV16-infected cells. In addition, 3C protease activity led to the redistribution of the nucleolin protein out of the nucleolus, but did not affect nuclear localisation of hnRNP proteins, implying that complete disruption of nucleocytoplasmic transport leading to relocalisation of hnRNP proteins from the nucleus to the cytoplasm in HRV-infected cells almost certainly requires 2A in addition to 3C protease. Thus, a specific role for HRV 3C protease in cleavage and mislocalisation of host cell nuclear proteins, in concert with 2A, is implicated for the first time in HRV pathogenesis.

  17. Host-pathogen interactions in specific pathogen-free chickens following aerogenous infection with Chlamydia psittaci and Chlamydia abortus.

    Science.gov (United States)

    Kalmar, Isabelle; Berndt, Angela; Yin, Lizi; Chiers, Koen; Sachse, Konrad; Vanrompay, Daisy

    2015-03-15

    Although Chlamydia (C.) psittaci infections are recognized as an important factor causing economic losses and impairing animal welfare in poultry production, the specific mechanisms leading to severe clinical outcomes are poorly understood. In the present study, we comparatively investigated pathology and host immune response, as well as systemic dissemination and expression of essential chlamydial genes in the course of experimental aerogeneous infection with C. psittaci and the closely related C. abortus, respectively, in specific pathogen-free chicks. Clinical signs appeared sooner and were more severe in the C. psittaci-infected group. Compared to C. abortus infection, more intense systemic dissemination of C. psittaci correlated with higher and faster infiltration of immune cells, as well as more macroscopic lesions and epithelial pathology, such as hyperplasia and erosion. In thoracic air sac tissue, mRNA expression of immunologically relevant factors, such as IFN-γ, IL-1β, IL-6, IL-17, IL-22, LITAF and iNOS was significantly stronger up-regulated in C. psittaci- than in C. abortus-infected birds between 3 and 14 days post-infection. Likewise, transcription rates of the chlamydial genes groEL, cpaf and ftsW were consistently higher in C. psittaci during the acute phase. These findings illustrate that the stronger replication of C. psittaci in its natural host also evoked a more intense immune response than in the case of C. abortus infection. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. The phylogenetic position of the enigmatic Balkan Aulopyge huegelii (Teleostei: Cyprinidae) from the perspective of host-specific Dactylogyrus parasites (Monogenea), with a description of Dactylogyrus omenti n. sp.

    Science.gov (United States)

    Benovics, Michal; Kičinjaová, Maria Lujza; Šimková, Andrea

    2017-11-03

    The host specificity of fish parasites is considered a useful parasite characteristic with respect to understanding the biogeography of their fish hosts. Dactylogyrus Diesing, 1850 (Monogenea) includes common parasites of cyprinids exhibiting different degrees of host specificity, i.e. from strict specialism to generalism. The phylogenetic relationships and historical dispersions of several cyprinid lineages, including Aulopyge huegelii Heckel, 1843, are still unclear. Therefore, the aims of our study were to investigate (i) the Dactylogyrus spp. parasites of A. huegelii, and (ii) the phylogenetic relationships of Dactylogyrus spp. parasitizing A. huegelii as a possible tool for understanding the phylogenetic position of this fish species within the Cyprininae lineage. Two species of Dactylogyrus, D. vastator Nybelin, 1924 and D. omenti n. sp., were collected from 14 specimens of A. huegelii from the Šujica River (Bosnia and Herzegovina). While D. vastator is a typical species parasitizing Carassius spp. and Cyprinus carpio L, D. omenti n. sp. is, according to phylogenetic reconstruction, closely related to Dactylogyrus species infecting European species of Barbus and Luciobarbus. The genetic distance revealed that the sequence for D. vastator from A. huegelii is identical with that for D. vastator from Barbus plebejus Bonaparte, 1839 (Italy) and Carassius gibelio (Bloch, 1782) (Croatia). Dactylogyrus omenti n. sp. was described as a species new to science. Our findings support the phylogenetic position of A. huegelii within the Cyprininae lineage and suggest that A. huegelii is phylogenetically closely related to Barbus and Luciobarbus species. The morphological similarity between D. omenti n. sp. and Dactylogyrus species of Middle Eastern Barbus suggests historical contact between cyprinid species recently living in allopatry and the possible diversification of A. huegelii from a common ancestor in this area. On other hand, the genetic similarity between D

  19. Host-specific serological response to Angiostrongylus vasorum infection in red foxes (Vulpes vulpes)

    DEFF Research Database (Denmark)

    Gillis-Germitsch, N.; Kapel, Christian; Thamsborg, Stig Milan

    2017-01-01

    Angiostrongylus vasorum is a cardiovascular nematode increasingly found in dogs and foxes in endemic foci throughout Europe. The present study evaluates ELISAs for detection of circulating antigens and specific antibodies against A. vasorum in foxes. Blood and worm burdens (WBs) from carcasses...... of 215 Swiss wild red foxes (Vulpes vulpes) and from 75 farmed foxes of different age groups experimentally inoculated once or repeatedly with infective doses of 50, 100 or 200 third-stage larvae were obtained. Antigen detection in the naturally infected Swiss foxes had 91·2% sensitivity and 89...

  20. Diversity of the skin microbiota of fishes: evidence for host species specificity.

    Science.gov (United States)

    Larsen, Andrea; Tao, Zhen; Bullard, Stephen A; Arias, Covadonga R

    2013-09-01

    Skin microbiota of Gulf of Mexico fishes were investigated by ribosomal internal spacer analysis (RISA) and 16S rRNA gene sequencing. A total of 102 fish specimens representing six species (Mugil cephalus, Lutjanus campechanus, Cynoscion nebulosus, Cynoscion arenarius, Micropogonias undulatus, and Lagodon rhomboides) were sampled at regular intervals throughout a year. The skin microbiota from each individual fish was analyzed by RISA and produced complex profiles with 23 bands on average. Similarities between RISA profiles ranged from 97.5% to 4.0%. At 70% similarity, 11 clusters were defined, each grouping individuals from the same fish species. Multidimensional scaling and analysis of similarity correlated the RISA-defined clusters with geographic locality, date, and fish species. Global R values indicated that fish species was the most indicative variable for group separation. Analysis of 16S rRNA gene sequences (from pooled samples of 10 individual fish for each fish species) showed that the Proteobacteria was the predominant phylum in skin microbiota, followed by the Firmicutes and the Actinobacteria. The distribution and abundance of bacterial sequences were different among all species analyzed. Aeribacillus was found in all fish species representing 19% of all clones sequenced, while some genera were fish species-specific (Neorickettsia in M. cephalus and Microbacterium in L. campechanus). Our data provide evidence for the existence of specific skin microbiota associated with particular fish species. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  1. Eudicot plant-specific sphingolipids determine host selectivity of microbial NLP cytolysins.

    Science.gov (United States)

    Lenarčič, Tea; Albert, Isabell; Böhm, Hannah; Hodnik, Vesna; Pirc, Katja; Zavec, Apolonija B; Podobnik, Marjetka; Pahovnik, David; Žagar, Ema; Pruitt, Rory; Greimel, Peter; Yamaji-Hasegawa, Akiko; Kobayashi, Toshihide; Zienkiewicz, Agnieszka; Gömann, Jasmin; Mortimer, Jenny C; Fang, Lin; Mamode-Cassim, Adiilah; Deleu, Magali; Lins, Laurence; Oecking, Claudia; Feussner, Ivo; Mongrand, Sébastien; Anderluh, Gregor; Nürnberger, Thorsten

    2017-12-15

    Necrosis and ethylene-inducing peptide 1-like (NLP) proteins constitute a superfamily of proteins produced by plant pathogenic bacteria, fungi, and oomycetes. Many NLPs are cytotoxins that facilitate microbial infection of eudicot, but not of monocot plants. Here, we report glycosylinositol phosphorylceramide (GIPC) sphingolipids as NLP toxin receptors. Plant mutants with altered GIPC composition were more resistant to NLP toxins. Binding studies and x-ray crystallography showed that NLPs form complexes with terminal monomeric hexose moieties of GIPCs that result in conformational changes within the toxin. Insensitivity to NLP cytolysins of monocot plants may be explained by the length of the GIPC head group and the architecture of the NLP sugar-binding site. We unveil early steps in NLP cytolysin action that determine plant clade-specific toxin selectivity. Copyright © 2017 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

  2. Biology, host specificity tests, and risk assessment of the sawfly Heteroperreyia hubrichi, a potential biological control agent of Schinus terebinthifolius in Hawaii

    Science.gov (United States)

    Abstract. Heteroperreyia hubrichi Malaise (Hymenoptera: Pergidae), a foliage feeding sawfly of Schinus terebinthifolius Raddi (Sapindales: Anacardiaceae), was studied to assess its suitability as a classical biological control agent of this invasive weed in Hawaii. Nochoice host-specificity tests we...

  3. Biogeography, Host Specificity, and Molecular Phylogeny of the Basidiomycetous Yeast Phaffia rhodozyma and Its Sexual Form, Xanthophyllomyces dendrorhous▿

    Science.gov (United States)

    Libkind, Diego; Ruffini, Alejandra; van Broock, Maria; Alves, Leonor; Sampaio, José Paulo

    2007-01-01

    Phaffia rhodozyma (sexual form, Xanthophyllomyces dendrorhous) is a basidiomycetous yeast that has been found in tree exudates in the Northern Hemisphere at high altitudes and latitudes. This yeast produces astaxanthin, a carotenoid pigment with biotechnological importance because it is used in aquaculture for fish pigmentation. We isolated X. dendrorhous from the Southern Hemisphere (Patagonia, Argentina), where it was associated with fruiting bodies of Cyttaria hariotii, an ascomycetous parasite of Nothofagus trees. We compared internal transcribed spacer (ITS)-based phylogenies of P. rhodozyma and its tree host (Betulaceae, Corneaceae, Fagaceae, and Nothofagaceae) and found them to be generally concordant, suggesting that different yeast lineages colonize different trees and providing an explanation for the phylogenetic distance observed between the type strains of P. rhodozyma and X. dendrorhous. We hypothesize that the association of Xanthophyllomyces with Cyttaria derives from a previous association of the yeast with Nothofagus, and the sister relationship between Nothofagaceae and Betulaceae plus Fagaceae correlates with the phylogeny of X. dendrorhous strains originating from these three plant families. The two most basal strains of X. dendrorhous are those isolated from Cornus, an ancestral genus in the phylogenetic analysis of the host trees. Thus, we question previous conclusions that P. rhodozyma and X. dendrorhous represent different species since the polymorphisms detected in the ITS and intergenic spacer sequences can be attributed to intraspecific variation associated with host specificity. Our study provides a deeper understanding of Phaffia biogeography, ecology, and molecular phylogeny. Such knowledge is essential for the comprehension of many aspects of the biology of this organism and will facilitate the study of astaxanthin production within an evolutionary and ecological framework. PMID:17189439

  4. Biogeography, host specificity, and molecular phylogeny of the basidiomycetous yeast Phaffia rhodozyma and its sexual form, Xanthophyllomyces dendrorhous.

    Science.gov (United States)

    Libkind, Diego; Ruffini, Alejandra; van Broock, Maria; Alves, Leonor; Sampaio, José Paulo

    2007-02-01

    Phaffia rhodozyma (sexual form, Xanthophyllomyces dendrorhous) is a basidiomycetous yeast that has been found in tree exudates in the Northern Hemisphere at high altitudes and latitudes. This yeast produces astaxanthin, a carotenoid pigment with biotechnological importance because it is used in aquaculture for fish pigmentation. We isolated X. dendrorhous from the Southern Hemisphere (Patagonia, Argentina), where it was associated with fruiting bodies of Cyttaria hariotii, an ascomycetous parasite of Nothofagus trees. We compared internal transcribed spacer (ITS)-based phylogenies of P. rhodozyma and its tree host (Betulaceae, Corneaceae, Fagaceae, and Nothofagaceae) and found them to be generally concordant, suggesting that different yeast lineages colonize different trees and providing an explanation for the phylogenetic distance observed between the type strains of P. rhodozyma and X. dendrorhous. We hypothesize that the association of Xanthophyllomyces with Cyttaria derives from a previous association of the yeast with Nothofagus, and the sister relationship between Nothofagaceae and Betulaceae plus Fagaceae correlates with the phylogeny of X. dendrorhous strains originating from these three plant families. The two most basal strains of X. dendrorhous are those isolated from Cornus, an ancestral genus in the phylogenetic analysis of the host trees. Thus, we question previous conclusions that P. rhodozyma and X. dendrorhous represent different species since the polymorphisms detected in the ITS and intergenic spacer sequences can be attributed to intraspecific variation associated with host specificity. Our study provides a deeper understanding of Phaffia biogeography, ecology, and molecular phylogeny. Such knowledge is essential for the comprehension of many aspects of the biology of this organism and will facilitate the study of astaxanthin production within an evolutionary and ecological framework.

  5. Baculovirus DNA Replication-Specific Expression Factors Trigger Apoptosis and Shutoff of Host Protein Synthesis during Infection▿

    Science.gov (United States)

    Schultz, Kimberly L. W.; Friesen, Paul D.

    2009-01-01

    Apoptosis is an important antivirus defense. To define the poorly understood pathways by which invertebrates respond to viruses by inducing apoptosis, we have identified replication events that trigger apoptosis in baculovirus-infected cells. We used RNA silencing to ablate factors required for multiplication of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). Transfection with double-stranded RNA (dsRNA) complementary to the AcMNPV late expression factors (lefs) that are designated as replicative lefs (lef-1, lef-2, lef-3, lef-11, p143, dnapol, and ie-1/ie-0) blocked virus DNA synthesis and late gene expression in permissive Spodoptera frugiperda cells. dsRNAs specific to designated nonreplicative lefs (lef-8, lef-9, p47, and pp31) blocked late gene expression without affecting virus DNA replication. Thus, both classes of lefs functioned during infection as defined. Silencing the replicative lefs prevented AcMNPV-induced apoptosis of Spodoptera cells, whereas silencing the nonreplicative lefs did not. Thus, the activity of replicative lefs or virus DNA replication is sufficient to trigger apoptosis. Confirming this conclusion, AcMNPV-induced apoptosis was suppressed by silencing the replicative lefs in cells from a divergent species, Drosophila melanogaster. Silencing replicative but not nonreplicative lefs also abrogated AcMNPV-induced shutdown of host protein synthesis, suggesting that virus DNA replication triggers inhibition of host biosynthetic processes and that apoptosis and translational arrest are linked. Our findings suggest that baculovirus DNA replication triggers a host cell response similar to the DNA damage response in vertebrates, which causes translational arrest and apoptosis. Pathways for detecting virus invasion and triggering apoptosis may therefore be conserved between insects and mammals. PMID:19706708

  6. Baculovirus DNA replication-specific expression factors trigger apoptosis and shutoff of host protein synthesis during infection.

    Science.gov (United States)

    Schultz, Kimberly L W; Friesen, Paul D

    2009-11-01

    Apoptosis is an important antivirus defense. To define the poorly understood pathways by which invertebrates respond to viruses by inducing apoptosis, we have identified replication events that trigger apoptosis in baculovirus-infected cells. We used RNA silencing to ablate factors required for multiplication of Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV). Transfection with double-stranded RNA (dsRNA) complementary to the AcMNPV late expression factors (lefs) that are designated as replicative lefs (lef-1, lef-2, lef-3, lef-11, p143, dnapol, and ie-1/ie-0) blocked virus DNA synthesis and late gene expression in permissive Spodoptera frugiperda cells. dsRNAs specific to designated nonreplicative lefs (lef-8, lef-9, p47, and pp31) blocked late gene expression without affecting virus DNA replication. Thus, both classes of lefs functioned during infection as defined. Silencing the replicative lefs prevented AcMNPV-induced apoptosis of Spodoptera cells, whereas silencing the nonreplicative lefs did not. Thus, the activity of replicative lefs or virus DNA replication is sufficient to trigger apoptosis. Confirming this conclusion, AcMNPV-induced apoptosis was suppressed by silencing the replicative lefs in cells from a divergent species, Drosophila melanogaster. Silencing replicative but not nonreplicative lefs also abrogated AcMNPV-induced shutdown of host protein synthesis, suggesting that virus DNA replication triggers inhibition of host biosynthetic processes and that apoptosis and translational arrest are linked. Our findings suggest that baculovirus DNA replication triggers a host cell response similar to the DNA damage response in vertebrates, which causes translational arrest and apoptosis. Pathways for detecting virus invasion and triggering apoptosis may therefore be conserved between insects and mammals.

  7. Host-specific induction of Escherichia coli fitness genes during human urinary tract infection.

    Science.gov (United States)

    Subashchandrabose, Sargurunathan; Hazen, Tracy H; Brumbaugh, Ariel R; Himpsl, Stephanie D; Smith, Sara N; Ernst, Robert D; Rasko, David A; Mobley, Harry L T

    2014-12-23

    Uropathogenic Escherichia coli (UPEC) is the predominant etiological agent of uncomplicated urinary tract infection (UTI), manifested by inflammation of the urinary bladder, in humans and is a major global public health concern. Molecular pathogenesis of UPEC has been primarily examined using murine models of UTI. Translational research to develop novel therapeutics against this major pathogen, which is becoming increasingly antibiotic resistant, requires a thorough understanding of mechanisms involved in pathogenesis during human UTIs. Total RNA-sequencing (RNA-seq) and comparative transcriptional analysis of UTI samples to the UPEC isolates cultured in human urine and laboratory medium were used to identify novel fitness genes that were specifically expressed during human infection. Evidence for UPEC genes involved in ion transport, including copper efflux, nickel and potassium import systems, as key fitness factors in uropathogenesis were generated using an experimental model of UTI. Translational application of this study was investigated by targeting Cus, a bacterial copper efflux system. Copper supplementation in drinking water reduces E. coli colonization in the urinary bladder of mice. Additionally, our results suggest that anaerobic processes in UPEC are involved in promoting fitness during UTI in humans. In summary, RNA-seq was used to establish the transcriptional signature in UPEC during naturally occurring, community acquired UTI in women and multiple novel fitness genes used by UPEC during human infection were identified. The repertoire of UPEC genes involved in UTI presented here will facilitate further translational studies to develop innovative strategies against UTI caused by UPEC.

  8. Strong stability and host specific bacterial community in faeces of ponies.

    Directory of Open Access Journals (Sweden)

    Tina M Blackmore

    Full Text Available The horse, as a hindgut fermenter, is reliant on its intestinal bacterial population for efficient diet utilisation. However, sudden disturbance of this population can result in severe colic or laminitis, both of which may require euthanasia. This study therefore aimed to determine the temporal stability of the bacterial population of faecal samples from six ponies maintained on a formulated high fibre diet. Bacterial 16S rRNA terminal restriction fragment length polymorphism (TRFLP analyses of 10 faecal samples collected from 6 ponies at regular intervals over 72 hour trial periods identified a significant pony-specific profile (P<0.001 with strong stability. Within each pony, a significantly different population was found after 11 weeks on the same diet (P<0.001 and with greater intra-individual similarity. Total short chain fatty acid (SCFA concentration increased in all ponies, but other changes (such as bacterial population diversity measures, individual major SCFA concentration were significant and dependent on the individual. This study is the first to report the extent of stability of microbes resident in the intestinal tract as represented with such depth and frequency of faecal sampling. In doing so, this provides a baseline from which future trials can be planned and the extent to which results may be interpreted.

  9. The length of a lantibiotic hinge region has profound influence on antimicrobial activity and host specificity

    Directory of Open Access Journals (Sweden)

    Liang eZhou

    2015-01-01

    Full Text Available Lantibiotics are ribosomally synthesized (methyllanthionine containing peptides which can efficiently inhibit the growth of Gram-positive bacteria. As lantibiotics kill bacteria efficiently and resistance to them is difficult to be obtained, they have the potential to be used in many applications, e.g. in pharmaceutical industry or food industry. Nisin can inhibit the growth of Gram-positive bacteria by binding to lipid II and by making pores in their membrane. The C-terminal part of nisin is known to play an important role during translocation over the membrane and forming pore complexes. However, as the thickness of bacterial membranes varies between different species and environmental conditions, this property could have an influence on the pore forming activity of nisin. To investigate this, the so-called hinge region of nisin (residues NMK was engineered to vary from one to six amino acid residues and specific activity against different indicators was compared. Antimicrobial activity in liquid culture assays showed that wild type nisin is most active, while truncation of the hinge region dramatically reduced the activity of the peptide. However, one or two amino acids extensions showed only slightly reduced activity against most indicator strains. Notably, some variants (+2, +1, -1, -2 exhibited higher antimicrobial activity than nisin in agar well diffusion assays against Lactococcus lactis MG1363, Listeria monocytogenes, Enterococcus faecalis VE14089, Bacillus sporothermodurans IC4 and Bacillus cereus 4153 at certain temperatures.

  10. Predicting fecal sources in waters with diverse pollution loads using general and molecular host-specific indicators and applying machine learning methods

    OpenAIRE

    Casanovas Massana, Arnau; Gómez Doñate, Marta; Sánchez, David; Belanche Muñoz, Luis Antonio; Muniesa, Maite; Blanch, Anicet R.

    2015-01-01

    In this study we use a machine learning software (Ichnaea) to generate predictive models for water samples with different concentrations of fecal contamination (point source, moderate and low). We applied several MST methods (host-specific Bacteroides phages, mitochondrial DNA genetic markers, Bifidobacterium adolescentis and Bifidobacterium dentium markers, and bifidobacterial host-specific qPCR), and general indicators (Escherichia colt, enterococci and somatic coliphages) to evaluate the s...

  11. Stage-Specific Changes in Plasmodium Metabolism Required for Differentiation and Adaptation to Different Host and Vector Environments.

    Directory of Open Access Journals (Sweden)

    Anubhav Srivastava

    2016-12-01

    Full Text Available Malaria parasites (Plasmodium spp. encounter markedly different (nutritional environments during their complex life cycles in the mosquito and human hosts. Adaptation to these different host niches is associated with a dramatic rewiring of metabolism, from a highly glycolytic metabolism in the asexual blood stages to increased dependence on tricarboxylic acid (TCA metabolism in mosquito stages. Here we have used stable isotope labelling, targeted metabolomics and reverse genetics to map stage-specific changes in Plasmodium berghei carbon metabolism and determine the functional significance of these changes on parasite survival in the blood and mosquito stages. We show that glutamine serves as the predominant input into TCA metabolism in both asexual and sexual blood stages and is important for complete male gametogenesis. Glutamine catabolism, as well as key reactions in intermediary metabolism and CoA synthesis are also essential for ookinete to oocyst transition in the mosquito. These data extend our knowledge of Plasmodium metabolism and point towards possible targets for transmission-blocking intervention strategies. Furthermore, they highlight significant metabolic differences between Plasmodium species which are not easily anticipated based on genomics or transcriptomics studies and underline the importance of integration of metabolomics data with other platforms in order to better inform drug discovery and design.

  12. Vertebrate host specificity and experimental vectors of Plasmodium (Novyella) kempi sp. n. from the eastern wild turkey in Iowa.

    Science.gov (United States)

    Christensen, B M; Barnes, H J; Rowley, W A

    1983-07-01

    Vertebrate host specificity, experimental laboratory vectors, and a description of Plasmodium (Novyella) kempi sp. n. from eastern wild turkeys (Meleagris gallopavo silvestris Vieillot) in Iowa are presented. Plasmodium kempi is infective for domestic turkeys, bobwhites (Colinus virginianus), chukars (Alectoris graeca), guinea fowl (Numida meleagris), peacocks (Pavo cristatus), and canaries (Serinus canaria), produces a transient infection in mallards (Anas platyrhynchos) and domestic geese (Anser anser), but will not infect ring-necked pheasants (Phasianus colchicus), pigeons (Columba livia), Japanese quail (Coturnix coturnix), leghorn white chickens (Gallus gallus), or starlings (Sturnus vulgaris). Oocysts and (or) sporozoites were recovered from 68% (84/124) and 98% (60/61) of the Culex pipiens pipiens and C. tarsalis examined, respectively. Oocysts developed faster and sporozoites invaded the salivary glands sooner in C. tarsalis (6 days) than in C. p. pipiens (7 days). Culex tarsalis transmitted P. kempi more effectively than C. p. pipiens, although both species were capable of transmitting the parasite by natural feeding. Oocysts developed and sporozoites also were produced in C. restuans, but its ability to transmit the parasite was not determined. Aedes aegypti (Rockefeller strain) and A. triseriatus were refractive to P. kempi. Plasmodium kempi produces trophozoites with large refractile globules and fine cytoplasmic extensions, mature schizonts in the form of a condensed fan containing four to eight nuclei (usually 5), and elongate gametocytes with irregular borders. All stages are confined almost exclusively to mature erythrocytes, with no effect on host cell size or position of host cell nucleus. Plasmodium kempi is most similar morphologically to P. (Novyella) hexamerium and P. (Novyella) vaughani. It differs from P. hexamerium in having large refractile globules in trophozoites and immature schizonts, an inability to infect starlings, an absence of

  13. Cleavage of host cytokeratin-6 by lysine-specific gingipain induces gingival inflammation in periodontitis patients.

    Directory of Open Access Journals (Sweden)

    Salunya Tancharoen

    Full Text Available Lysine-specific gingipain (Kgp is a virulence factor secreted from Porphyromonas gingivalis (P. gingivalis, a major etiological bacterium of periodontal disease. Keratin intermediate filaments maintain the structural integrity of gingival epithelial cells, but are targeted by Kgp to produce a novel cytokeratin 6 fragment (K6F. We investigated the release of K6F and its induction of cytokine secretion.K6F present in the gingival crevicular fluid of periodontal disease patients and in gingipain-treated rat gingival epithelial cell culture supernatants was measured by matrix-assisted laser desorption/ionization time-of-flight mass spectrometer-based rapid quantitative peptide analysis using BLOTCHIP. K6F in gingival tissues was immunostained, and cytokeratin 6 protein was analyzed by immunofluorescence staining and flow cytometry. Activation of MAPK in gingival epithelial cells was evaluated by immunoblotting. ELISA was used to measure K6F and the cytokines release induced by K6F. Human gingival fibroblast migration was assessed using a Matrigel invasion chamber assay.We identified K6F, corresponding to the C-terminus region of human cytokeratin 6 (amino acids 359-378, in the gingival crevicular fluid of periodontal disease patients and in the supernatant from gingival epithelial cells cultured with Kgp. K6F antigen was distributed from the basal to the spinous epithelial layers in gingivae from periodontal disease patients. Cytokeratin 6 on gingival epithelial cells was degraded by Kgp, but not by Arg-gingipain, P. gingivalis lipopolysaccharide or Actinobacillus actinomycetemcomitans lipopolysaccharide. K6F, but not a scrambled K6F peptide, induced human gingival fibroblast migration and secretion of interleukin (IL-6, IL-8 and monocyte chemoattractant protein-1. These effects of K6F were mediated by activation of p38 MAPK and Jun N-terminal kinase, but not p42/44 MAPK or p-Akt.Kgp degrades gingival epithelial cell cytokeratin 6 to K6F that, on

  14. Endophytic Fungal Communities Associated with Vascular Plants in the High Arctic Zone Are Highly Diverse and Host-Plant Specific.

    Directory of Open Access Journals (Sweden)

    Tao Zhang

    Full Text Available This study assessed the diversity and distribution of endophytic fungal communities associated with the leaves and stems of four vascular plant species in the High Arctic using 454 pyrosequencing with fungal-specific primers targeting the ITS region. Endophytic fungal communities showed high diversity. The 76,691 sequences obtained belonged to 250 operational taxonomic units (OTUs. Of these OTUs, 190 belonged to Ascomycota, 50 to Basidiomycota, 1 to Chytridiomycota, and 9 to unknown fungi. The dominant orders were Helotiales, Pleosporales, Capnodiales, and Tremellales, whereas the common known fungal genera were Cryptococcus, Rhizosphaera, Mycopappus, Melampsora, Tetracladium, Phaeosphaeria, Mrakia, Venturia, and Leptosphaeria. Both the climate and host-related factors might shape the fungal communities associated with the four Arctic plant species in this region. These results suggested the presence of an interesting endophytic fungal community and could improve our understanding of fungal evolution and ecology in the Arctic terrestrial ecosystems.

  15. "Strict" Anadeixis, Discourse Deixis and Text Structuring

    Science.gov (United States)

    Cornish, Francis

    2011-01-01

    Taking English as the example language, the article begins by presenting a Scale of indexicality characterizing context-bound expression types, ranging from those signalling pure deixis at one pole, to ones expressing pure anaphora at the other. On the basis of this Scale, the article attempts to determine the specific way in which demonstratives…

  16. The specific host plant DNA detection suggests a potential migration of Apolygus lucorum from cotton to mungbean fields.

    Directory of Open Access Journals (Sweden)

    Qian Wang

    Full Text Available The polyphagous mirid bug Apolygus lucorum (Heteroptera: Miridae has more than 200 species of host plants and is an insect pest of important agricultural crops, including cotton (Gossypium hirsutum and mungbean (Vigna radiata. Previous field trials have shown that A. lucorum adults prefer mungbean to cotton plants, indicating the considerable potential of mungbean as a trap crop in cotton fields. However, direct evidence supporting the migration of A. lucorum adults from cotton to mungbean is lacking. We developed a DNA-based polymerase chain reaction (PCR approach to reveal the movement of A. lucorum between neighboring mungbean and cotton fields. Two pairs of PCR primers specific to cotton or mungbean were designed to target the trnL-trnF region of chloroplast DNA. Significant differences in the detectability half-life (DS50 were observed between these two host plants, and the mean for cotton (8.26 h was approximately two times longer than that of mungbean (4.38 h, requiring weighted mean calculations to compare the detectability of plant DNA in the guts of field-collected bugs. In field trials, cotton DNA was detected in the guts of the adult A. lucorum individuals collected in mungbean plots, and the cotton DNA detection rate decreased successively from 5 to 15 m away from the mungbean-cotton midline. In addition to the specific detection of cotton- and mungbean-fed bugs, both cotton and mungbean DNA were simultaneously detected within the guts of single individuals caught from mungbean fields. This study successfully established a tool for molecular gut-content analyses and clearly demonstrated the movement of A. lucorum adults from cotton to neighboring mungbean fields, providing new insights into understanding the feeding characteristics and landscape-level ecology of A. lucorum under natural conditions.

  17. HY-Specific Induced Regulatory T Cells Display High Specificity and Efficacy in the Prevention of Acute Graft-versus-Host Disease.

    Science.gov (United States)

    Li, Jun; Heinrichs, Jessica; Haarberg, Kelley; Semple, Kenrick; Veerapathran, Anandharaman; Liu, Chen; Anasetti, Claudio; Yu, Xue-Zhong

    2015-07-15

    Naturally derived regulatory T cells (Tregs) may prevent graft-versus-host disease (GVHD) while preserving graft-versus-leukemia (GVL) activity. However, clinical application of naturally derived regulatory T cells has been severely hampered by their scarce availability and nonselectivity. To overcome these limitations, we took alternative approaches to generate Ag-specific induced Tregs (iTregs) and tested their efficacy and selectivity in the prevention of GVHD in preclinical models of bone marrow transplantation. We selected HY as a target Ag because it is a naturally processed, ubiquitously expressed minor histocompatibility Ag (miHAg) with a proven role in GVHD and GVL effect. We generated HY-specific iTregs (HY-iTregs) from resting CD4 T cells derived from TCR transgenic mice, in which CD4 cells specifically recognize HY peptide. We found that HY-iTregs were highly effective in preventing GVHD in male (HY(+)) but not female (HY(-)) recipients using MHC II-mismatched, parent→F1, and miHAg-mismatched murine bone marrow transplantation models. Interestingly, the expression of target Ag (HY) on the hematopoietic or nonhematopoietic compartment alone was sufficient for iTregs to prevent GVHD. Furthermore, treatment with HY-iTregs still preserved the GVL effect even against pre-established leukemia. We found that HY-iTregs were more stable in male than in female recipients. Furthermore, HY-iTregs expanded extensively in male but not female recipients, which in turn significantly reduced donor effector T cell expansion, activation, and migration into GVHD target organs, resulting in effective prevention of GVHD. This study demonstrates that iTregs specific for HY miHAgs are highly effective in controlling GVHD in an Ag-dependent manner while sparing the GVL effect. Copyright © 2015 by The American Association of Immunologists, Inc.

  18. Modal Inclusion Logic: Being Lax is Simpler than Being Strict

    DEFF Research Database (Denmark)

    Hella, Lauri; Kuusisto, Antti Johannes; Meier, Arne

    2015-01-01

    We investigate the computational complexity of the satisfiability problem of modal inclusion logic. We distinguish two variants of the problem: one for strict and another one for lax semantics. The complexity of the lax version turns out to be complete for EXPTIME, whereas with strict semantics...

  19. 7 CFR 28.431 - Strict Middling Tinged Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Middling Tinged Color. 28.431 Section 28.431 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Color. Strict Middling Tinged Color is color which is better than Middling Tinged Color. ...

  20. 7 CFR 28.433 - Strict Low Middling Tinged Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Low Middling Tinged Color. 28.433 Section 28.433 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Tinged Color. Strict Low Middling Tinged Color is color which is within the range represented by a set of...

  1. 7 CFR 28.424 - Strict Low Middling Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Low Middling Spotted Color. 28.424 Section 28.424 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Spotted Color. Strict Low Middling Spotted Color is color which is within the range represented by a set...

  2. 7 CFR 28.426 - Strict Good Ordinary Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Good Ordinary Spotted Color. 28.426 Section 28.426 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Spotted Color. Strict Good Ordinary Spotted Color is color which is within the range represented by a set...

  3. 7 CFR 28.422 - Strict Middling Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 2 2010-01-01 2010-01-01 false Strict Middling Spotted Color. 28.422 Section 28.422 Agriculture Regulations of the Department of Agriculture AGRICULTURAL MARKETING SERVICE (Standards... Color. Strict Middling Spotted Color is color which is within the range represented by a set of samples...

  4. Strictly-regular number system and data structures

    DEFF Research Database (Denmark)

    Elmasry, Amr Ahmed Abd Elmoneim; Jensen, Claus; Katajainen, Jyrki

    2010-01-01

    We introduce a new number system that we call the strictly-regular system, which efficiently supports the operations: digit-increment, digit-decrement, cut, concatenate, and add. Compared to other number systems, the strictly-regular system has distinguishable properties. It is superior to the re...

  5. Inhibition of Host Cell Lysosome Spreading by Trypanosoma cruzi Metacyclic Stage-Specific Surface Molecule gp90 Downregulates Parasite Invasion.

    Science.gov (United States)

    Rodrigues, João Paulo Ferreira; Sant'ana, Guilherme Hideki Takahashi; Juliano, Maria Aparecida; Yoshida, Nobuko

    2017-09-01

    Successful infection by Trypanosoma cruzi , the agent of Chagas' disease, is critically dependent on host cell invasion by metacyclic trypomastigote (MT) forms. Two main metacyclic stage-specific surface molecules, gp82 and gp90, play determinant roles in target cell invasion in vitro and in oral T. cruzi infection in mice. The structure and properties of gp82, which is highly conserved among T. cruzi strains, are well known. Information on gp90 is still rather sparse. Here, we attempted to fill that gap. gp90, purified from poorly invasive G strain MT and expressing gp90 at high levels, inhibited HeLa cell lysosome spreading and the gp82-mediated internalization of a highly invasive CL strain MT expressing low levels of a diverse gp90 molecule. A recombinant protein containing the conserved C-terminal domain of gp90 exhibited the same properties as the native G strain gp90: it counteracted the host cell lysosome spreading induced by recombinant gp82 and exhibited an inhibitory effect on HeLa cell invasion by CL strain MT. Assays to identify the gp90 sequence associated with the property of downregulating MT invasion, using synthetic peptides spanning the gp90 C-terminal domain, revealed the sequence GVLYTADKEW. These data, plus the findings that lysosome spreading was induced upon HeLa cell interaction with CL strain MT, but not with G strain MT, and that in mixed infection CL strain MT internalization was inhibited by G strain MT, suggest that the inhibition of target cell lysosome spreading is the mechanism by which the gp90 molecule exerts its downregulatory role. Copyright © 2017 Rodrigues et al.

  6. Sex-specific effects of parasitism on survival and reproduction of a rodent host in a subtropical montane region.

    Science.gov (United States)

    Lo, Hsuan-Yi; Shaner, Pei-Jen L

    2015-03-01

    Parasites can generate complex life history trade-offs in a host. In this study, we experimentally reduced the infection level of intestinal helminth parasites in the Taiwan field mouse (Apodemus semotus) to test (1) whether parasite richness and load are biased towards male or female mice (sex-biased parasitism) and (2) whether the effects of parasitism on the host's survival and reproduction are different between the sexes (sex-specific effects of parasitism). Our findings indicate that neither parasite richness (number of helminth taxa found in a fecal sample) nor parasite load (number of helminth eggs per gram of fecal material) was sexually biased in our A. semotus study population. These results are in agreement with those of previous studies on endoparasites in Apodemus spp., but are in contrast to those on ectoparasites in Apodemus spp. Parasite removal reduced the survival rate of reproducing females, possibly by allowing reproducing females to increase maternal investment in their current litters at the cost of their own future survival. Single-litter mothers with reduced parasitism had a higher body mass than the untreated single-litter mothers, suggesting an increased maternal investment. In addition, the reproductively more active A. semotus, particularly the females, carried higher parasite loads, suggesting a trade-off between reproduction and parasite defense. By demonstrating that parasites can affect life history trade-offs in A. semotus, our results highlight the importance of maintaining variation in life history traits under parasitism risks and illustrate the subtle demographic processes (e.g. reduced future survival among healthy reproducing females) that might be driven by parasitism.

  7. Brugia malayi excreted/secreted proteins at the host/parasite interface: stage- and gender-specific proteomic profiling.

    Directory of Open Access Journals (Sweden)

    Sasisekhar Bennuru

    Full Text Available Relatively little is known about the filarial proteins that interact with the human host. Although the filarial genome has recently been completed, protein profiles have been limited to only a few recombinants or purified proteins of interest. Here, we describe a large-scale proteomic analysis using microcapillary reverse-phase liquid chromatography-tandem-mass spectrometry to identify the excretory-secretory (ES products of the L3, L3 to L4 molting ES, adult male, adult female, and microfilarial stages of the filarial parasite Brugia malayi. The analysis of the ES products from adult male, adult female, microfilariae (Mf, L3, and molting L3 larvae identified 852 proteins. Annotation suggests that the functional and component distribution was very similar across each of the stages studied; however, the Mf contributed a higher proportion to the total number of identified proteins than the other stages. Of the 852 proteins identified in the ES, only 229 had previous confirmatory expressed sequence tags (ESTs in the available databases. Moreover, this analysis was able to confirm the presence of 274 "hypothetical" proteins inferred from gene prediction algorithms applied to the B. malayi (Bm genome. Not surprisingly, the majority (160/274 of these "hypothetical" proteins were predicted to be secreted by Signal IP and/or SecretomeP 2.0 analysis. Of major interest is the abundance of previously characterized immunomodulatory proteins such as ES-62 (leucyl aminopeptidase, MIF-1, SERPIN, glutathione peroxidase, and galectin in the ES of microfilariae (and Mf-containing adult females compared to the adult males. In addition, searching the ES protein spectra against the Wolbachia database resulted in the identification of 90 Wolbachia-specific proteins, most of which were metabolic enzymes that have not been shown to be immunogenic. This proteomic analysis extends our knowledge of the ES and provides insight into the host-parasite interaction.

  8. Commensal Bacteroides species induce colitis in host-genotype-specific fashion in a mouse model of inflammatory bowel disease

    Science.gov (United States)

    Bloom, Seth M.; Bijanki, Vinieth N.; Nava, Gerardo M.; Sun, Lulu; Malvin, Nicole P.; Donermeyer, David L.; Dunne, W. Michael; Allen, Paul M.; Stappenbeck, Thaddeus S.

    2011-01-01

    SUMMARY The intestinal microbiota is important for induction of inflammatory bowel disease (IBD). IBD is associated with complex shifts in microbiota composition, but it is unclear whether specific bacterial subsets induce IBD and, if so, whether their proportions in the microbiota are altered during disease. Here we fulfilled Koch’s postulates in host-genotype-specific fashion using a mouse model of IBD with human-relevant disease-susceptibility mutations. From screening experiments we isolated common commensal Bacteroides species, introduced them into antibiotic-pretreated mice, and quantitatively re-isolated them in culture. The bacteria colonized IBD-susceptible and non-susceptible mice equivalently, but induced disease exclusively in susceptible animals. Conversely, commensal Enterobacteriaceae were >100-fold enriched during spontaneous disease but an Enterobacteriaceae isolate failed to induce disease in antibiotic-pretreated mice despite robust colonization. We thus demonstrate that IBD-associated microbiota alterations do not necessarily reflect underlying disease etiology. These findings establish important experimental criteria and a conceptual framework for understanding microbial contributions to IBD. PMID:21575910

  9. Trypanosoma cruzi Evades the Complement System as an Efficient Strategy to Survive in the Mammalian Host: The Specific Roles of Host/Parasite Molecules and Trypanosoma cruzi Calreticulin

    Science.gov (United States)

    Ramírez-Toloza, Galia; Ferreira, Arturo

    2017-01-01

    American Trypanosomiasis is an important neglected reemerging tropical parasitism, infecting about 8 million people worldwide. Its agent, Trypanosoma cruzi, exhibits multiple mechanisms to evade the host immune response and infect host cells. An important immune evasion strategy of T. cruzi infective stages is its capacity to inhibit the complement system activation on the parasite surface, avoiding opsonizing, immune stimulating and lytic effects. Epimastigotes, the non-infective form of the parasite, present in triatomine arthropod vectors, are highly susceptible to complement-mediated lysis while trypomastigotes, the infective form, present in host bloodstream, are resistant. Thus T. cruzi susceptibility to complement varies depending on the parasite stage (amastigote, trypomastigotes or epimastigote) and on the T. cruzi strain. To avoid complement-mediated lysis, T. cruzi trypomastigotes express on the parasite surface a variety of complement regulatory proteins, such as glycoprotein 58/68 (gp58/68), T. cruzi complement regulatory protein (TcCRP), trypomastigote decay-accelerating factor (T-DAF), C2 receptor inhibitor trispanning (CRIT) and T. cruzi calreticulin (TcCRT). Alternatively, or concomitantly, the parasite captures components with complement regulatory activity from the host bloodstream, such as factor H (FH) and plasma membrane-derived vesicles (PMVs). All these proteins inhibit different steps of the classical (CP), alternative (AP) or lectin pathways (LP). Thus, TcCRP inhibits the CP C3 convertase assembling, gp58/68 inhibits the AP C3 convertase, T-DAF interferes with the CP and AP convertases assembling, TcCRT inhibits the CP and LP, CRIT confers ability to resist the CP and LP, FH is used by trypomastigotes to inhibit the AP convertases and PMVs inhibit the CP and LP C3 convertases. Many of these proteins have similar molecular inhibitory mechanisms. Our laboratory has contributed to elucidate the role of TcCRT in the host-parasite interplay

  10. Trypanosoma cruzi Evades the Complement System as an Efficient Strategy to Survive in the Mammalian Host: The Specific Roles of Host/Parasite Molecules and Trypanosoma cruzi Calreticulin

    Directory of Open Access Journals (Sweden)

    Galia Ramírez-Toloza

    2017-09-01

    Full Text Available American Trypanosomiasis is an important neglected reemerging tropical parasitism, infecting about 8 million people worldwide. Its agent, Trypanosoma cruzi, exhibits multiple mechanisms to evade the host immune response and infect host cells. An important immune evasion strategy of T. cruzi infective stages is its capacity to inhibit the complement system activation on the parasite surface, avoiding opsonizing, immune stimulating and lytic effects. Epimastigotes, the non-infective form of the parasite, present in triatomine arthropod vectors, are highly susceptible to complement-mediated lysis while trypomastigotes, the infective form, present in host bloodstream, are resistant. Thus T. cruzi susceptibility to complement varies depending on the parasite stage (amastigote, trypomastigotes or epimastigote and on the T. cruzi strain. To avoid complement-mediated lysis, T. cruzi trypomastigotes express on the parasite surface a variety of complement regulatory proteins, such as glycoprotein 58/68 (gp58/68, T. cruzi complement regulatory protein (TcCRP, trypomastigote decay-accelerating factor (T-DAF, C2 receptor inhibitor trispanning (CRIT and T. cruzi calreticulin (TcCRT. Alternatively, or concomitantly, the parasite captures components with complement regulatory activity from the host bloodstream, such as factor H (FH and plasma membrane-derived vesicles (PMVs. All these proteins inhibit different steps of the classical (CP, alternative (AP or lectin pathways (LP. Thus, TcCRP inhibits the CP C3 convertase assembling, gp58/68 inhibits the AP C3 convertase, T-DAF interferes with the CP and AP convertases assembling, TcCRT inhibits the CP and LP, CRIT confers ability to resist the CP and LP, FH is used by trypomastigotes to inhibit the AP convertases and PMVs inhibit the CP and LP C3 convertases. Many of these proteins have similar molecular inhibitory mechanisms. Our laboratory has contributed to elucidate the role of TcCRT in the host

  11. In vivo fitness correlates with host-specific virulence of Infectious hematopoietic necrosis virus (IHNV) in sockeye salmon and rainbow trout

    Science.gov (United States)

    Penaranda, M.M.D.; Wargo, A.R.; Kurath, G.

    2011-01-01

    The relationship between virulence and overall within-host fitness of the fish rhabdovirus Infectious hematopoietic necrosis virus (IHNV) was empirically investigated in vivo for two virus isolates belonging to different IHNV genogroups that exhibit opposing host-specific virulence. U group isolates are more virulent in sockeye salmon and M group isolates are more virulent in rainbow trout. In both single and mixed infections in the two fish hosts, the more virulent IHNV type exhibited higher prevalence and higher viral load than the less virulent type. Thus, a positive correlation was observed between higher in vivo fitness and higher host-specific virulence in sockeye salmon and rainbow trout. Comparisons of mean viral loads in single and mixed infections revealed no evidence for limitation due to competition effects between U and M viruses in either rainbow trout or sockeye salmon co-infections.

  12. The influenza fingerprints: NS1 and M1 proteins contribute to specific host cell ultrastructure signatures upon infection by different influenza A viruses

    Energy Technology Data Exchange (ETDEWEB)

    Terrier, Olivier; Moules, Vincent; Carron, Coralie; Cartet, Gaeelle [Equipe VirCell, Laboratoire de Virologie et Pathologie Humaine, VirPath EMR 4610, Universite de Lyon, Universite Claude Bernard Lyon 1, Hospices Civils de Lyon, Faculte de medecine RTH Laennec, rue Guillaume Paradin, F-69008 Lyon (France); Frobert, Emilie [Laboratoire de Virologie, Centre de Biologie et de Pathologie Est, Hospices Civils de Lyon, 59 boulevard Pinel, F-69677 Bron Cedex, Lyon (France); Yver, Matthieu; Traversier, Aurelien [Equipe VirCell, Laboratoire de Virologie et Pathologie Humaine, VirPath EMR 4610, Universite de Lyon, Universite Claude Bernard Lyon 1, Hospices Civils de Lyon, Faculte de medecine RTH Laennec, rue Guillaume Paradin, F-69008 Lyon (France); Wolff, Thorsten [Division of Influenza/Respiratory Viruses, Robert Koch Institute, Nordufer 20, D-13353 Berlin (Germany); Riteau, Beatrice [Laboratoire de Virologie et Pathologie Humaine, VirPath EMR 4610, Universite de Lyon, Universite Claude Bernard Lyon 1, Hospices Civils de Lyon, Faculte de medecine RTH Laennec, rue Guillaume Paradin, F-69008 Lyon (France); Naffakh, Nadia [Institut Pasteur, Unite de Genetique Moleculaire des Virus Respiratoires, URA CNRS 3015, EA302 Universite Paris Diderot, Paris (France); and others

    2012-10-10

    Influenza A are nuclear replicating viruses which hijack host machineries in order to achieve optimal infection. Numerous functional virus-host interactions have now been characterized, but little information has been gathered concerning their link to the virally induced remodeling of the host cellular architecture. In this study, we infected cells with several human and avian influenza viruses and we have analyzed their ultrastructural modifications by using electron and confocal microscopy. We discovered that infections lead to a major and systematic disruption of nucleoli and the formation of a large number of diverse viral structures showing specificity that depended on the subtype origin and genomic composition of viruses. We identified NS1 and M1 proteins as the main actors in the remodeling of the host ultra-structure and our results suggest that each influenza A virus strain could be associated with a specific cellular fingerprint, possibly correlated to the functional properties of their viral components.

  13. Host specificity and experimental assessment of the early establishment of the mistletoe Phoradendron crassifolium (Pohl ex DC. Eichler (Santalaceae in a fragment of Atlantic Forest in southeast Brazil

    Directory of Open Access Journals (Sweden)

    Patrícia Aparecida Messias

    2014-12-01

    Full Text Available Mistletoe establishment relies heavily on a seed reaching a proper host plant. Small frugivorous birds usually disperse large numbers of mistletoe seeds. However, in the field, mistletoes are absent from some potential available hosts. We investigated whether the mistletoe Phoradendron crassifolium has some preferences for specific host trees in a fragment of Atlantic Forest in southeast Brazil. We surveyed 397 tree individuals of 50 species within 25 families. Seven of those species (14% bore P. crassifolium infections. Although prevalence at the individual level was low (11.6%, there were marked deviations in infection levels among species and families. Most (87% of the infections (40 of 46 occurred in species belonging to the families Anacardiaceae (Lithraea molleoides and Tapirira guianensis and Siparunaceae (Siparuna guianensis, which nevertheless accounted for only 26% of the potential individual hosts (103 of 397. We also performed an experiment simulating bird behavior. We inoculated 480 mistletoe seeds to the bark of four potential hosts in field, following the fate of the seeds for five months. No differences in host preference were observed. The low specificity detected at the local level was confirmed by a survey of exsiccata collected over the geographical distribution of the mistletoe, suggesting that P. crassifolium prevalence is more dependent on dispersal limitation than on mistletoe-host compatibility.

  14. Host specific diversity in Lactobacillus johnsonii as evidenced by a major chromosomal inversion and phage resistance mechanisms.

    Science.gov (United States)

    Guinane, Caitriona M; Kent, Robert M; Norberg, Sarah; Hill, Colin; Fitzgerald, Gerald F; Stanton, Catherine; Ross, R Paul

    2011-04-20

    Genetic diversity and genomic rearrangements are a driving force in bacterial evolution and niche adaptation. We sequenced and annotated the genome of Lactobacillus johnsonii DPC6026, a strain isolated from the porcine intestinal tract. Although the genome of DPC6026 is similar in size (1.97 mbp) and GC content (34.8%) to the sequenced human isolate L. johnsonii NCC 533, a large symmetrical inversion of approximately 750 kb differentiated the two strains. Comparative analysis among 12 other strains of L. johnsonii including 8 porcine, 3 human and 1 poultry isolate indicated that the genome architecture found in DPC6026 is more common within the species than that of NCC 533. Furthermore a number of unique features were annotated in DPC6026, some of which are likely to have been acquired by horizontal gene transfer (HGT) and contribute to protection against phage infection. A putative type III restriction-modification system was identified, as were novel Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR) elements. Interestingly, these particular elements are not widely distributed among L. johnsonii strains. Taken together these data suggest intra-species genomic rearrangements and significant genetic diversity within the L. johnsonii species and indicate towards a host-specific divergence of L. johnsonii strains with respect to genome inversion and phage exposure.

  15. Host specific diversity in Lactobacillus johnsonii as evidenced by a major chromosomal inversion and phage resistance mechanisms.

    Directory of Open Access Journals (Sweden)

    Caitriona M Guinane

    Full Text Available Genetic diversity and genomic rearrangements are a driving force in bacterial evolution and niche adaptation. We sequenced and annotated the genome of Lactobacillus johnsonii DPC6026, a strain isolated from the porcine intestinal tract. Although the genome of DPC6026 is similar in size (1.97 mbp and GC content (34.8% to the sequenced human isolate L. johnsonii NCC 533, a large symmetrical inversion of approximately 750 kb differentiated the two strains. Comparative analysis among 12 other strains of L. johnsonii including 8 porcine, 3 human and 1 poultry isolate indicated that the genome architecture found in DPC6026 is more common within the species than that of NCC 533. Furthermore a number of unique features were annotated in DPC6026, some of which are likely to have been acquired by horizontal gene transfer (HGT and contribute to protection against phage infection. A putative type III restriction-modification system was identified, as were novel Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR elements. Interestingly, these particular elements are not widely distributed among L. johnsonii strains. Taken together these data suggest intra-species genomic rearrangements and significant genetic diversity within the L. johnsonii species and indicate towards a host-specific divergence of L. johnsonii strains with respect to genome inversion and phage exposure.

  16. Repeatedly Evolved Host-Specific Ectosymbioses between Sulfur-Oxidizing Bacteria and Amphipods Living in a Cave Ecosystem

    Science.gov (United States)

    Bauermeister, Jan; Ramette, Alban; Dattagupta, Sharmishtha

    2012-01-01

    Ectosymbioses between invertebrates and sulfur-oxidizing bacteria are widespread in sulfidic marine environments and have evolved independently in several invertebrate phyla. The first example from a freshwater habitat, involving Niphargus ictus amphipods and filamentous Thiothrix ectosymbionts, was recently reported from the sulfide-rich Frasassi caves in Italy. Subsequently, two new Niphargus species, N. frasassianus and N. montanarius, were discovered within Frasassi and found to co-occur with N. ictus. Using a variety of microscopic and molecular techniques, we found that all three Frasassi-dwelling Niphargus species harbor Thiothrix ectosymbionts, which belong to three distinct phylogenetic clades (named T1, T2, and T3). T1 and T3 Thiothrix dominate the N. frasassianus ectosymbiont community, whereas T2 and T3 are prevalent on N. ictus and N. montanarius. Relative distribution patterns of the three ectosymbionts are host species-specific and consistent over different sampling locations and collection years. Free-living counterparts of T1–T3 are rare or absent in Frasassi cave microbial mats, suggesting that ectosymbiont transmission among Niphargus occurs primarily through inter- or intraspecific inoculations. Phylogenetic analyses indicate that the Niphargus-Thiothrix association has evolved independently at least two times. While ectosymbioses with T1 and T2 may have been established within Frasassi, T3 ectosymbionts seem to have been introduced to the cave system by Niphargus. PMID:23209690

  17. Repeatedly evolved host-specific ectosymbioses between sulfur-oxidizing bacteria and amphipods living in a cave ecosystem.

    Directory of Open Access Journals (Sweden)

    Jan Bauermeister

    Full Text Available Ectosymbioses between invertebrates and sulfur-oxidizing bacteria are widespread in sulfidic marine environments and have evolved independently in several invertebrate phyla. The first example from a freshwater habitat, involving Niphargus ictus amphipods and filamentous Thiothrix ectosymbionts, was recently reported from the sulfide-rich Frasassi caves in Italy. Subsequently, two new Niphargus species, N. frasassianus and N. montanarius, were discovered within Frasassi and found to co-occur with N. ictus. Using a variety of microscopic and molecular techniques, we found that all three Frasassi-dwelling Niphargus species harbor Thiothrix ectosymbionts, which belong to three distinct phylogenetic clades (named T1, T2, and T3. T1 and T3 Thiothrix dominate the N. frasassianus ectosymbiont community, whereas T2 and T3 are prevalent on N. ictus and N. montanarius. Relative distribution patterns of the three ectosymbionts are host species-specific and consistent over different sampling locations and collection years. Free-living counterparts of T1-T3 are rare or absent in Frasassi cave microbial mats, suggesting that ectosymbiont transmission among Niphargus occurs primarily through inter- or intraspecific inoculations. Phylogenetic analyses indicate that the Niphargus-Thiothrix association has evolved independently at least two times. While ectosymbioses with T1 and T2 may have been established within Frasassi, T3 ectosymbionts seem to have been introduced to the cave system by Niphargus.

  18. Genetic diversity and host specificity varies across three genera of blood parasites in ducks of the Pacific Americas Flyway

    Science.gov (United States)

    Reeves, Andrew B.; Smith, Matthew M.; Meixell, Brandt W.; Fleskes, Joseph P.; Ramey, Andrew M.

    2015-01-01

    Birds of the order Anseriformes, commonly referred to as waterfowl, are frequently infected by Haemosporidia of the genera Haemoproteus, Plasmodium, and Leucocytozoon via dipteran vectors. We analyzed nucleotide sequences of the Cytochrome b (Cytb) gene from parasites of these genera detected in six species of ducks from Alaska and California, USA to characterize the genetic diversity of Haemosporidia infecting waterfowl at two ends of the Pacific Americas Flyway. In addition, parasite Cytb sequences were compared to those available on a public database to investigate specificity of genetic lineages to hosts of the order Anseriformes. Haplotype and nucleotide diversity of Haemoproteus Cytb sequences was lower than was detected for Plasmodium and Leucocytozoon parasites. Although waterfowl are presumed to be infected by only a single species of Leucocytozoon, L. simondi, diversity indices were highest for haplotypes from this genus and sequences formed five distinct clades separated by genetic distances of 4.9%–7.6%, suggesting potential cryptic speciation. All Haemoproteus andLeucocytozoon haplotypes derived from waterfowl samples formed monophyletic clades in phylogenetic analyses and were unique to the order Anseriformes with few exceptions. In contrast, waterfowl-origin Plasmodium haplotypes were identical or closely related to lineages found in other avian orders. Our results suggest a more generalist strategy for Plasmodiumparasites infecting North American waterfowl as compared to those of the generaHaemoproteus and Leucocytozoon.

  19. Taxonomy, host specificity and dietary implications of Hurleytrematoides (Digenea: Monorchiidae) from chaetodontid fishes on the Great Barrier Reef.

    Science.gov (United States)

    McNamara, M K A; Cribb, T H

    2011-09-01

    Five new and five previously described species of Hurleytrematoides are reported from 19 of 34 chaetodontid species examined from the Great Barrier Reef; new species are H. faliexae n. sp., H. galzini n. sp., H. loi n. sp., H. morandi n. sp., and H. sasali n. sp. Previously described species are H. coronatum, H. fijiensis, H. prevoti, H. bartolii, and H. zebrasomae. The genus is rediagnosed in the light of morphological variation of the new species; the degree of spination and shape of the terminal genitalia distinguish individual species. Species of Hurleytrematoides infect almost every clade of the family Chaetodontidae found on the Great Barrier Reef, but obligate corallivores are not infected. All ten species were found at Heron Island on the southern Great Barrier Reef, but only six at Lizard Island on the northern Great Barrier Reef. For three of the four species not present at Lizard Island, the absence appears to be statistically significant. Although all species are apparently restricted to chaetodontids on the GBR, specificity within the family varies from oioxenous to euryxenous; a core/satellite host paradigm explains the distribution of several species. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  20. Pseudomonas aeruginosa Cell Membrane Protein Expression from Phenotypically Diverse Cystic Fibrosis Isolates Demonstrates Host-Specific Adaptations.

    Science.gov (United States)

    Kamath, Karthik Shantharam; Pascovici, Dana; Penesyan, Anahit; Goel, Apurv; Venkatakrishnan, Vignesh; Paulsen, Ian T; Packer, Nicolle H; Molloy, Mark P

    2016-07-01

    Pseudomonas aeruginosa is a Gram-negative, nosocomial, highly adaptable opportunistic pathogen especially prevalent in immuno-compromised cystic fibrosis (CF) patients. The bacterial cell surface proteins are important contributors to virulence, yet the membrane subproteomes of phenotypically diverse P. aeruginosa strains are poorly characterized. We carried out mass spectrometry (MS)-based proteome analysis of the membrane proteins of three novel P. aeruginosa strains isolated from the sputum of CF patients and compared protein expression to the widely used laboratory strain, PAO1. Microbes were grown in planktonic growth condition using minimal M9 media, and a defined synthetic lung nutrient mimicking medium (SCFM) limited passaging. Two-dimensional LC-MS/MS using iTRAQ labeling enabled quantitative comparisons among 3171 and 2442 proteins from the minimal M9 medium and in the SCFM, respectively. The CF isolates showed marked differences in membrane protein expression in comparison with PAO1 including up-regulation of drug resistance proteins (MexY, MexB, MexC) and down-regulation of chemotaxis and aerotaxis proteins (PA1561, PctA, PctB) and motility and adhesion proteins (FliK, FlgE, FliD, PilJ). Phenotypic analysis using adhesion, motility, and drug susceptibility assays confirmed the proteomics findings. These results provide evidence of host-specific microevolution of P. aeruginosa in the CF lung and shed light on the adaptation strategies used by CF pathogens.

  1. Strict finitism and the logic of mathematical applications

    CERN Document Server

    Ye, Feng

    2011-01-01

    Exploring the logic behind applied mathematics to the physical world, this volume illustrates how radical naturalism, nominalism and strict finitism can account for the applications of classical mathematics in current theories about natural phenomena.

  2. Strict monotonicity and unique continuation of the biharmonic operator

    Directory of Open Access Journals (Sweden)

    Najib Tsouli

    2012-01-01

    Full Text Available In this paper, we will show that the strict monotonicity of the eigenvalues of the biharmonic operator holds if and only if some unique continuation property is satisfied by the corresponding eigenfunctions.

  3. Two examples of non strictly convex large deviations

    OpenAIRE

    De Marco, Stefano; Jacquier, Antoine; Roome, Patrick

    2016-01-01

    We present two examples of a large deviations principle where the rate function is not strictly convex. This is motivated by a model used in mathematical finance (the Heston model), and adds a new item to the zoology of non strictly convex large deviations. For one of these examples, we show that the rate function of the Cramer-type of large deviations coincides with that of the Freidlin-Wentzell when contraction principles are applied.

  4. Gene expression of a green fluorescent protein homolog as a host-specific biomarker of heat stress within a reef-building coral.

    Science.gov (United States)

    Smith-Keune, C; Dove, S

    2008-01-01

    Recent incidences of mass coral bleaching indicate that major reef building corals are increasingly suffering thermal stress associated with climate-related temperature increases. The development of pulse amplitude modulated (PAM) fluorometry has enabled rapid detection of the onset of thermal stress within coral algal symbionts, but sensitive biomarkers of thermal stress specific to the host coral have been slower to emerge. Differential display reverse transcription polymerase chain reaction (DDRT-PCR) was used to produce fingerprints of gene expression for the reef-building coral Acropora millepora exposed to 33 degrees C. Changes in the expression of 23 out of 399 putative genes occurred within 144 h. Down-regulation of one host-specific gene (AmA1a) occurred within just 6 h. Full-length sequencing revealed the product of this gene to be an all-protein chromatophore (green fluorescent protein [GFP]-homolog). RT-PCR revealed consistent down-regulation of this GFP-homolog for three replicate colonies within 6 h at both 32 degrees C and 33 degrees C but not at lower temperatures. Down-regulation of this host gene preceded significant decreases in the photosynthetic activity of photosystem II (dark-adapted F (v)/F (m)) of algal symbionts as measured by PAM fluorometry. Gene expression of host-specific genes such as GFP-homologs may therefore prove to be highly sensitive indicators for the onset of thermal stress within host coral cells.

  5. The Tail Associated Protein of Acinetobacter baumannii Phage ΦAB6 Is the Host Specificity Determinant Possessing Exopolysaccharide Depolymerase Activity.

    Directory of Open Access Journals (Sweden)

    Meng-Jiun Lai

    Full Text Available Acinetobacter baumannii is a non-fermenting, gram-negative bacterium. In recent years, the frequency of A. baumannii infections has continued to increase, and multidrug-resistant strains are emerging in hospitalized patients. Therefore, as therapeutic options become limited, the potential of phages as natural antimicrobial agents to control infections is worth reconsidering. In our previous study, we isolated ten virulent double-stranded DNA A. baumannii phages, ϕAB1-9 and ϕAB11, and found that each has a narrow host range. Many reports indicate that receptor-binding protein of phage mediates host recognition; however, understanding of the specific interactions between A. baumannii and phages remains very limited. In this study, host determinants of A. baumannii phages were investigated. Sequence comparison of ϕAB6 and ϕAB1 revealed high degrees of conservation among their genes except the tail fiber protein (ORF41 in ϕAB1 and ORF40 in ϕAB6. Furthermore, we found that ORF40ϕAB6 has polysaccharide depolymerase activity capable of hydrolyzing the A. baumannii exopolysaccharide and is a component of the phage tail apparatus determining host specificity. Thus, the lytic phages and their associated depolymerase not only have potential as alternative therapeutic agents for treating A. baumannii infections but also provide useful and highly specific tools for studying host strain exopolysaccharides and producing glycoconjugate vaccines.

  6. Strictly contractive quantum channels and physically realizable quantum computers

    International Nuclear Information System (INIS)

    Raginsky, Maxim

    2002-01-01

    We study the robustness of quantum computers under the influence of errors modeled by strictly contractive channels. A channel T is defined to be strictly contractive if, for any pair of density operators ρ, σ in its domain, parallel Tρ-Tσ parallel 1 ≤k parallel ρ-σ parallel 1 for some 0≤k 1 denotes the trace norm). In other words, strictly contractive channels render the states of the computer less distinguishable in the sense of quantum detection theory. Starting from the premise that all experimental procedures can be carried out with finite precision, we argue that there exists a physically meaningful connection between strictly contractive channels and errors in physically realizable quantum computers. We show that, in the absence of error correction, sensitivity of quantum memories and computers to strictly contractive errors grows exponentially with storage time and computation time, respectively, and depends only on the constant k and the measurement precision. We prove that strict contractivity rules out the possibility of perfect error correction, and give an argument that approximate error correction, which covers previous work on fault-tolerant quantum computation as a special case, is possible

  7. Wheat streak mosaic virus coat protein is a host-specific long-distance transport determinant in oat

    Science.gov (United States)

    Viral determinants involved in systemic infection of hosts by monocot-infecting plant viruses are poorly understood. Wheat streak mosaic virus (WSMV, genus Tritimovirus, family Potyviridae) exclusively infects monocotyledonous crops such as wheat, oat, barley, maize, triticale, and rye. Previously, ...

  8. The phylogenetic position of the enigmatic Balkan Aulopyge huegelii (Teleostei: Cyprinidae from the perspective of host-specific Dactylogyrus parasites (Monogenea, with a description of Dactylogyrus omenti n. sp.

    Directory of Open Access Journals (Sweden)

    Michal Benovics

    2017-11-01

    Full Text Available Abstract Background The host specificity of fish parasites is considered a useful parasite characteristic with respect to understanding the biogeography of their fish hosts. Dactylogyrus Diesing, 1850 (Monogenea includes common parasites of cyprinids exhibiting different degrees of host specificity, i.e. from strict specialism to generalism. The phylogenetic relationships and historical dispersions of several cyprinid lineages, including Aulopyge huegelii Heckel, 1843, are still unclear. Therefore, the aims of our study were to investigate (i the Dactylogyrus spp. parasites of A. huegelii, and (ii the phylogenetic relationships of Dactylogyrus spp. parasitizing A. huegelii as a possible tool for understanding the phylogenetic position of this fish species within the Cyprininae lineage. Results Two species of Dactylogyrus, D. vastator Nybelin, 1924 and D. omenti n. sp., were collected from 14 specimens of A. huegelii from the Šujica River (Bosnia and Herzegovina. While D. vastator is a typical species parasitizing Carassius spp. and Cyprinus carpio L, D. omenti n. sp. is, according to phylogenetic reconstruction, closely related to Dactylogyrus species infecting European species of Barbus and Luciobarbus. The genetic distance revealed that the sequence for D. vastator from A. huegelii is identical with that for D. vastator from Barbus plebejus Bonaparte, 1839 (Italy and Carassius gibelio (Bloch, 1782 (Croatia. Dactylogyrus omenti n. sp. was described as a species new to science. Conclusions Our findings support the phylogenetic position of A. huegelii within the Cyprininae lineage and suggest that A. huegelii is phylogenetically closely related to Barbus and Luciobarbus species. The morphological similarity between D. omenti n. sp. and Dactylogyrus species of Middle Eastern Barbus suggests historical contact between cyprinid species recently living in allopatry and the possible diversification of A. huegelii from a common ancestor in this area

  9. Strict or graduated punishment? Effect of punishment strictness on the evolution of cooperation in continuous public goods games.

    Directory of Open Access Journals (Sweden)

    Hajime Shimao

    Full Text Available Whether costly punishment encourages cooperation is one of the principal questions in studies on the evolution of cooperation and social sciences. In society, punishment helps deter people from flouting rules in institutions. Specifically, graduated punishment is a design principle for long-enduring common-pool resource institutions. In this study, we investigate whether graduated punishment can promote a higher cooperation level when each individual plays the public goods game and has the opportunity to punish others whose cooperation levels fall below the punisher's threshold. We then examine how spatial structure affects evolutionary dynamics when each individual dies inversely proportional to the game score resulting from the social interaction and another player is randomly chosen from the population to produce offspring to fill the empty site created after a player's death. Our evolutionary simulation outcomes demonstrate that stricter punishment promotes increased cooperation more than graduated punishment in a spatially structured population, whereas graduated punishment increases cooperation more than strict punishment when players interact with randomly chosen opponents from the population. The mathematical analysis also supports the results.

  10. Strict or Graduated Punishment? Effect of Punishment Strictness on the Evolution of Cooperation in Continuous Public Goods Games

    Science.gov (United States)

    Shimao, Hajime; Nakamaru, Mayuko

    2013-01-01

    Whether costly punishment encourages cooperation is one of the principal questions in studies on the evolution of cooperation and social sciences. In society, punishment helps deter people from flouting rules in institutions. Specifically, graduated punishment is a design principle for long-enduring common-pool resource institutions. In this study, we investigate whether graduated punishment can promote a higher cooperation level when each individual plays the public goods game and has the opportunity to punish others whose cooperation levels fall below the punisher’s threshold. We then examine how spatial structure affects evolutionary dynamics when each individual dies inversely proportional to the game score resulting from the social interaction and another player is randomly chosen from the population to produce offspring to fill the empty site created after a player’s death. Our evolutionary simulation outcomes demonstrate that stricter punishment promotes increased cooperation more than graduated punishment in a spatially structured population, whereas graduated punishment increases cooperation more than strict punishment when players interact with randomly chosen opponents from the population. The mathematical analysis also supports the results. PMID:23555826

  11. Bacillus thuringiensis Is an Environmental Pathogen and Host-Specificity Has Developed as an Adaptation to Human-Generated Ecological Niches

    Science.gov (United States)

    Argôlo-Filho, Ronaldo Costa; Loguercio, Leandro Lopes

    2013-01-01

    Bacillus thuringiensis (Bt) has been used successfully as a biopesticide for more than 60 years. More recently, genes encoding their toxins have been used to transform plants and other organisms. Despite the large amount of research on this bacterium, its true ecology is still a matter of debate, with two major viewpoints dominating: while some understand Bt as an insect pathogen, others see it as a saprophytic bacteria from soil. In this context, Bt’s pathogenicity to other taxa and the possibility that insects may not be the primary targets of Bt are also ideas that further complicate this scenario. The existence of conflicting research results, the difficulty in developing broader ecological and genetics studies, and the great genetic plasticity of this species has cluttered a definitive concept. In this review, we gathered information on the aspects of Bt ecology that are often ignored, in the attempt to clarify the lifestyle, mechanisms of transmission and target host range of this bacterial species. As a result, we propose an integrated view to account for Bt ecology. Although Bt is indeed a pathogenic bacterium that possesses a broad arsenal for virulence and defense mechanisms, as well as a wide range of target hosts, this seems to be an adaptation to specific ecological changes acting on a versatile and cosmopolitan environmental bacterium. Bt pathogenicity and host-specificity was favored evolutionarily by increased populations of certain insect species (or other host animals), whose availability for colonization were mostly caused by anthropogenic activities. These have generated the conditions for ecological imbalances that favored dominance of specific populations of insects, arachnids, nematodes, etc., in certain areas, with narrower genetic backgrounds. These conditions provided the selective pressure for development of new hosts for pathogenic interactions, and so, host specificity of certain strains. PMID:26462580

  12. Community Sampling and Integrative Taxonomy Reveal New Species and Host Specificity in the Army Ant-Associated Beetle Genus Tetradonia (Coleoptera, Staphylinidae, Aleocharinae)

    Science.gov (United States)

    von Beeren, Christoph; Maruyama, Munetoshi; Kronauer, Daniel J. C.

    2016-01-01

    Army ant colonies host a diverse community of arthropod symbionts. Among the best-studied symbiont communities are those of Neotropical army ants of the genus Eciton. It is clear, however, that even in these comparatively well studied systems, a large proportion of symbiont biodiversity remains unknown. Even more striking is our lack of knowledge regarding the nature and specificity of these host-symbiont interactions. Here we surveyed the diversity and host specificity of rove beetles of the genus Tetradonia Wasmann, 1894 (Staphylinidae: Aleocharinae). Systematic community sampling of 58 colonies of the six local Eciton species at La Selva Biological Station, Costa Rica, combined with an integrative taxonomic approach, allowed us to uncover species diversity, host specificity, and co-occurrence patterns of symbionts in unprecedented detail. We used an integrative taxonomic approach combining morphological and genetic analyses, to delineate species boundaries. Mitochondrial DNA barcodes were analyzed for 362 Tetradonia specimens, and additional nuclear markers for a subset of 88 specimens. All analyses supported the presence of five Tetradonia species, including two species new to science. Host specificity is highly variable across species, ranging from generalists such as T. laticeps, which parasitizes all six local Eciton species, to specialists such as T. lizonae, which primarily parasitizes a single species, E. hamatum. Here we provide a dichotomous key along with diagnostic molecular characters for identification of Tetradonia species at La Selva Biological Station. By reliably assessing biodiversity and providing tools for species identification, we hope to set the baseline for future studies of the ecological and evolutionary dynamics in these species-rich host-symbiont networks. PMID:27829037

  13. The Mouse Intestinal Bacterial Collection (miBC) provides host-specific insight into cultured diversity and functional potential of the gut microbiota

    DEFF Research Database (Denmark)

    Lagkouvardos, Ilias; Pukall, Rüdiger; Abt, Birte

    2016-01-01

    BC), a public repository of bacterial strains and associated genomes from the mouse gut, and studied host-specificity of colonization and sequence-based relevance of the resource. The collection includes several strains representing novel species, genera and even one family. Genomic analyses showed that certain...

  14. DNA Fingerprinting To Improve Data Collection Efficiency and Yield in a Host-Specificity Test of a Weed Biological Control Candidate

    Science.gov (United States)

    An open-field test was conducted in southern France to assess the host-specificity of Ceratapion basicorne, a candidate for biological control of yellow starthistle (Centaurea solstitialis; YST). Test plants were infested by naturally occurring populations of C. basicorne but were also exposed to s...

  15. Genome-wide association study identifies vitamin B5 biosynthesis as a host specificity factor in Campylobacter.

    Science.gov (United States)

    Sheppard, Samuel K; Didelot, Xavier; Meric, Guillaume; Torralbo, Alicia; Jolley, Keith A; Kelly, David J; Bentley, Stephen D; Maiden, Martin C J; Parkhill, Julian; Falush, Daniel

    2013-07-16

    Genome-wide association studies have the potential to identify causal genetic factors underlying important phenotypes but have rarely been performed in bacteria. We present an association mapping method that takes into account the clonal population structure of bacteria and is applicable to both core and accessory genome variation. Campylobacter is a common cause of human gastroenteritis as a consequence of its proliferation in multiple farm animal species and its transmission via contaminated meat and poultry. We applied our association mapping method to identify the factors responsible for adaptation to cattle and chickens among 192 Campylobacter isolates from these and other host sources. Phylogenetic analysis implied frequent host switching but also showed that some lineages were strongly associated with particular hosts. A seven-gene region with a host association signal was found. Genes in this region were almost universally present in cattle but were frequently absent in isolates from chickens and wild birds. Three of the seven genes encoded vitamin B5 biosynthesis. We found that isolates from cattle were better able to grow in vitamin B5-depleted media and propose that this difference may be an adaptation to host diet.

  16. The Mouse Intestinal Bacterial Collection (miBC) provides host-specific insight into cultured diversity and functional potential of the gut microbiota

    DEFF Research Database (Denmark)

    Lagkouvardos, Ilias; Pukall, Rüdiger; Abt, Birte

    2016-01-01

    BC), a public repository of bacterial strains and associated genomes from the mouse gut, and studied host-specificity of colonization and sequence-based relevance of the resource. The collection includes several strains representing novel species, genera and even one family. Genomic analyses showed that certain...... of intestinal microbiomes and their interactions with diet and host. It is thus important to study in detail the diversity and functions of gut microbiota members, including those colonizing the mouse intestine. To address these issues, we aimed at establishing the Mouse Intestinal Bacterial Collection (mi...... and molecular studies. The resource is available at www.dsmz.de/miBC....

  17. Convergence theorems for strictly hemi-contractive maps

    International Nuclear Information System (INIS)

    Chidume, C.E.; Osilike, M.O.

    1992-04-01

    It is proved that each of two well-known fixed point iteration methods (the Mann and the Ishikawa iteration methods) converges strongly to the fixed point of strictly hemi-contractive map in real Banach spaces with property (U, λ, m+1,m), λ is an element of R, m is an element of IN. The class of strictly hemi-contractive maps includes all strictly pseudo-contractive maps with nonempty fixed point sets; and Banach spaces with property (U, λ, m+1, m), λ is an element of R, m is an element of IN include the L p (or l p ) spaces, p≥2. Our theorems generalize important known results. (author). 22 refs

  18. Host species and habitat affect nodulation by specific Frankia genotypes in two species of Alnus in interior Alaska

    Science.gov (United States)

    Michael Damon Anderson; Roger W. Ruess; David D. Myrold; D. Lee. Taylor

    2009-01-01

    This study examined the genetic structure (nifD-K spacer RFLP haplotypes) of Frankia assemblages symbiotic with two species of Alnus (A. tenuifolia and A. viridis) in four successional habitats in interior Alaska. We used one habitat in which both hosts occurred to...

  19. Genetic variation in Asterionella formosa (Bacillariophyceae) is it linked to frequent epidemics of host-specific parasitic fungi?

    NARCIS (Netherlands)

    De Bruin, A.; Ibelings, B.W.; Rijkeboer, M.; Brehm, Michaela; Van Donk, E.

    2004-01-01

    Understanding of the genetic basis for susceptibility and resistance is still lacking for most aquatic host-parasite systems, for instance, for phytoplankton and their fungal parasites. Fungal parasites can have significant effects on phytoplankton populations, mainly through their ability to

  20. Phytoalexin detoxification genes and gene products: Implication for the evolution of host specific traits for pathogenicity. Final report

    International Nuclear Information System (INIS)

    VanEtten, H.

    1997-01-01

    The overall objectives of this research were to determine which differences among PDA genes were associated with different levels of virulence on pea and to clone and characterize a MAK gene. The authors also proposed to characterize the pisatin detoxifying system in pea pathogens in addition to N. haematococca to assess whether pathogens of a common host had evolved similar pathogenicity genes

  1. Phytoalexin detoxification genes and gene products: Implication for the evolution of host specific traits for pathogenicity. Final report

    Energy Technology Data Exchange (ETDEWEB)

    VanEtten, H.

    1997-06-01

    The overall objectives of this research were to determine which differences among PDA genes were associated with different levels of virulence on pea and to clone and characterize a MAK gene. The authors also proposed to characterize the pisatin detoxifying system in pea pathogens in addition to N. haematococca to assess whether pathogens of a common host had evolved similar pathogenicity genes.

  2. The EG95 antigen of Echinococcus spp. contains positively selected amino acids, which may influence host specificity and vaccine efficacy.

    Science.gov (United States)

    Haag, Karen Luisa; Gottstein, Bruno; Ayala, Francisco Jose

    2009-01-01

    Echinococcosis is a worldwide zoonotic parasitic disease of humans and various herbivorous domestic animals (intermediate hosts) transmitted by the contact with wild and domestic carnivores (definitive hosts), mainly foxes and dogs. Recently, a vaccine was developed showing high levels of protection against one parasite haplotype (G1) of Echinococcus granulosus, and its potential efficacy against distinct parasite variants or species is still unclear. Interestingly, the EG95 vaccine antigen is a secreted glycosylphosphatydilinositol (GPI)-anchored protein containing a fibronectin type III domain, which is ubiquitous in modular proteins involved in cell adhesion. EG95 is highly expressed in oncospheres, the parasite life cycle stage which actively invades the intermediate hosts. After amplifying and sequencing the complete CDS of 57 Echinococcus isolates belonging to 7 distinct species, we uncovered a large amount of genetic variability, which may influence protein folding. Two positively selected sites are outside the vaccine epitopes, but are predicted to alter protein conformation. Moreover, phylogenetic analyses indicate that EG95 isoform evolution is convergent with regard to the number of beta-sheets and alpha-helices. We conclude that having a variety of EG95 isoforms is adaptive for Echinococcus parasites, in terms of their ability to invade different hosts, and we propose that a mixture of isoforms could possibly maximize vaccine efficacy.

  3. Alloreactivity of virus-specific T cells: possible implication of graft-versus-host disease and graft-versus-leukemia effects.

    Science.gov (United States)

    Fuji, Shigeo; Kapp, Markus; Einsele, Hermann

    2013-10-14

    Immune reconstitution of functional virus-specific T cells after allogeneic hematopoietic stem cell transplantation (HSCT) has been intensively investigated. However, the possible role of crossreactivity of these virus-specific T cells against allogeneic targets is still unclear. Theoretically, as in the field of organ transplantation, virus-specific T cells possess crossreactivity potential after allogeneic HSCT. Such crossreactivity is assumed to play a role in graft-versus-host disease and graft-versus-leukemia effects. In this article, we aim to give a comprehensive overview of current understanding about crossreactivity of virus-specific T cells.

  4. Mitochondrial COI and morphological evidence for host specificity of the black cherry aphids Myzus cerasi (Fabricius, 1775) collected from different cherry tree species in Europe (Hemiptera, Aphididae).

    Science.gov (United States)

    Rakauskas, Rimantas; Havelka, Jekaterina; Zaremba, Audrius; Bernotienė, Rasa

    2014-01-01

    Partial sequences of the mitochondrial COI gene of forty eight European and two Turkish population samples of Myzus cerasi from different winter hosts (Prunus spp.) were subjected to phylogenetic analyses. The analysed M. cerasi samples emerged as paraphyletic relative to a Myzus borealis sample used as an out-group, and formed two major clades in neighbor joining, maximum parsimony, maximum likelihood and Bayesian inference trees, corresponding to subspecies living specifically on Prunus avium and P. cerasus. Multivariate discriminant analysis (method of canonical variates) was applied to find out if morphological variation of samples correlated with mitochondrial COI and host plant information. Mean scores on the first two canonical variables clustered samples fully in accordance with their COI haplotypes and host plants confirming the existence of two morphologically similar winter host - specific subspecies of M. cerasi in Europe. No single morphological character enabled satisfactory discrimination between apterous viviparous females of the two subspecies. A three-character linear discriminant function enabled 92.37% correct identification of apterous viviparous females of M. cerasi cerasi (n = 118) and 93.64% of M. cerasi pruniavium (n = 110). A key for the morphological identification of the two subspecies is presented and their taxonomic status is discussed.

  5. Mitochondrial COI and morphological evidence for host specificity of the black cherry aphids Myzus cerasi (Fabricius, 1775 collected from different cherry tree species in Europe (Hemiptera, Aphididae

    Directory of Open Access Journals (Sweden)

    Rimantas Rakauskas

    2014-03-01

    Full Text Available Partial sequences of the mitochondrial COI gene of forty eight European and two Turkish population samples of Myzus cerasi from different winter hosts (Prunus spp. were subjected to phylogenetic analyses. The analysed M. cerasi samples emerged as paraphyletic relative to a Myzus borealis sample used as an out-group, and formed two major clades in neighbor joining, maximum parsimony, maximum likelihood and Bayesian inference trees, corresponding to subspecies living specifically on Prunus avium and P. cerasus. Multivariate discriminant analysis (method of canonical variates was applied to find out if morphological variation of samples correlated with mitochondrial COI and host plant information. Mean scores on the first two canonical variables clustered samples fully in accordance with their COI haplotypes and host plants confirming the existence of two morphologically similar winter host - specific subspecies of M.cerasi in Europe. No single morphological character enabled satisfactory discrimination between apterous viviparous females of the two subspecies. A three-character linear discriminant function enabled 92.37% correct identification of apterous viviparous females of M. cerasi cerasi (n=118 and 93.64% of M. cerasi pruniavium (n=110. A key for the morphological identification of the two subspecies is presented and their taxonomic status is discussed.

  6. Endophytic bacterial communities in three arctic plants from low arctic fell tundra are cold-adapted and host-plant specific.

    Science.gov (United States)

    Nissinen, Riitta M; Männistö, Minna K; van Elsas, Jan Dirk

    2012-11-01

    Endophytic bacteria inhabit internal plant tissues, and have been isolated from a large diversity of plants, where they form nonpathogenic relationships with their hosts. This study combines molecular and culture-dependent approaches to characterize endophytic bacterial communities of three arcto-alpine plant species (Oxyria digyna, Diapensia lapponica and Juncus trifidus) sampled in the low Arctic (69°03'N). Analyses of a 325 bacterial endophyte isolates, as well as seven clone libraries, revealed a high diversity. In particular, members of the Actinobacteria, Bacteroidetes, Firmicutes, Acidobacteria, and Proteobacteria were found. The compositions of the endophytic bacterial communities were dependent on host-plant species as well as on snow cover at sampling sites. Several bacterial genera were found to be associated tightly with specific host-plant species. In particular, Sphingomonas spp. were characteristic for D. lapponica and O. digyna, and their phylogenetic grouping corresponded to the host plant. Most of the endophyte isolates grew well and retained activity at +4 °C, and isolate as well as clone library sequences were often highly similar to sequences from bacteria from cold environments. Taken together, this study shows that arctic plants harbour a diverse community of bacterial endophytes, a portion of which seems to be tightly associated with specific plant species. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  7. Host Specificity for Bacterial, Archaeal and Fungal Communities Determined for High- and Low-Microbial Abundance Sponge Species in Two Genera

    Directory of Open Access Journals (Sweden)

    Maryam Chaib De Mares

    2017-12-01

    Full Text Available Sponges are engaged in intimate symbioses with a diversity of microorganisms from all three domains of life, namely Bacteria, Archaea and Eukarya. Sponges have been well studied and categorized for their bacterial communities, some displaying a high microbial abundance (HMA, while others show low microbial abundance (LMA. However, the associated Archaea and Eukarya have remained relatively understudied. We assessed the bacterial, archaeal and eukaryotic diversities in the LMA sponge species Dysidea avara and Dysidea etheria by deep amplicon sequencing, and compared the results to those in the HMA sponges Aplysina aerophoba and Aplysina cauliformis. D. avara and A. aerophoba are sympatric in the Mediterranean Sea, while D. etheria and A. cauliformis are sympatric in the Caribbean Sea. The bacterial communities followed a host-specific pattern, with host species identity explaining most of the variation among samples. We identified OTUs shared by the Aplysina species that support a more ancient association of these microbes, before the split of the two species studied here. These shared OTUs are suitable targets for future studies of the microbial traits that mediate interactions with their hosts. Even though the archaeal communities were not as rich as the bacterial ones, we found a remarkable diversification and specificity of OTUs of the family Cenarchaeaceae and the genus Nitrosopumilus in all four sponge species studied. Similarly, the differences in fungal communities were driven by sponge identity. The structures of the communities of small eukaryotes such as dinophytes and ciliophores (alveolates, and stramenopiles, could not be explained by either sponge host, sponge genus or geographic location. Our analyses suggest that the host specificity that was previously described for sponge bacterial communities also extends to the archaeal and fungal communities, but not to other microbial eukaryotes.

  8. Mann iteration with errors for strictly pseudo-contractive mappings ...

    African Journals Online (AJOL)

    It is well known that any fixed point of a Lipschitzian strictly pseudo-contractive self mapping of a nonempty closed convex and bounded subset K of a Banach space X is unique [6] and may be norm approximated by an iterative procedure. In this paper, we show that Mann iteration with errors can be used to approximate the ...

  9. Dominated operators, absolutely summing operators and the strict ...

    African Journals Online (AJOL)

    b(X;E) be the space of all E-valued bounded continuous functions on X, equipped with the strict topology β. We study dominated and absolutely summing operators T : Cb(X;E) → F. We derive that if X is a locally compact Hausdorff space and E ...

  10. Convergence of GAOR Iterative Method with Strictly Diagonally Dominant Matrices

    Directory of Open Access Journals (Sweden)

    Guangbin Wang

    2011-01-01

    Full Text Available We discuss the convergence of GAOR method for linear systems with strictly diagonally dominant matrices. Moreover, we show that our results are better than ones of Darvishi and Hessari (2006, Tian et al. (2008 by using three numerical examples.

  11. Runaway selection for cooperation and strict-and-severe punishment.

    Science.gov (United States)

    Nakamaru, Mayuko; Dieckmann, Ulf

    2009-03-07

    Punishing defectors is an important means of stabilizing cooperation. When levels of cooperation and punishment are continuous, individuals must employ suitable social standards for defining defectors and for determining punishment levels. Here we investigate the evolution of a social reaction norm, or psychological response function, for determining the punishment level meted out by individuals in dependence on the cooperation level exhibited by their neighbors in a lattice-structured population. We find that (1) cooperation and punishment can undergo runaway selection, with evolution towards enhanced cooperation and an ever more demanding punishment reaction norm mutually reinforcing each other; (2) this mechanism works best when punishment is strict, so that ambiguities in defining defectors are small; (3) when the strictness of punishment can adapt jointly with the threshold and severity of punishment, evolution favors the strict-and-severe punishment of individuals who offer slightly less than average cooperation levels; (4) strict-and-severe punishment naturally evolves and leads to much enhanced cooperation when cooperation without punishment would be weak and neither cooperation nor punishment are too costly; and (5) such evolutionary dynamics enable the bootstrapping of cooperation and punishment, through which defectors who never punish gradually and steadily evolve into cooperators who punish those they define as defectors.

  12. Dominance on Strict Triangular Norms and Mulholland Inequality

    Czech Academy of Sciences Publication Activity Database

    Petrík, Milan

    2018-01-01

    Roč. 335, 15 March (2018), s. 3-17 ISSN 0165-0114 R&D Projects: GA ČR GJ15-07724Y Institutional support: RVO:67985807 Keywords : dominance relation * Mulholland inequality * strict triangular norm * transitivity Subject RIV: BA - General Mathematics Impact factor: 2.718, year: 2016

  13. Host-ectoparasite specificity in a small mammal community in an area of Atlantic Rain Forest (Ilha Grande, State of Rio de Janeiro, Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    Emerson Brum Bittencourt

    2003-09-01

    Full Text Available The analyses of the ectoparasite species associated with a small mammal community on Ilha Grande, a coastal island in southern of the state of Rio de Janeiro, Brazil, evaluated the level of host-ectoparasite specificity. Was used the Jaccard index for qualitative data to analyse the similarity. The lowest value of similarity occurred between Proechimys iheringi and Marmosops incanus and between Sciurus aestuans and Nectomys squamipes (Cj = 0.08 and the highest between P. iheringi and Oxymycterus sp. (Cj = 0.33. This index showed a low value of similarity across the ectoparasite community. The only exception from this pattern of high host specificity occurred with P. iheringi and Oxymycterus sp., which shared five species of ectoparasites. The similarity values, for most of the cases, is smaller than 0.2.

  14. Virus-Inspired Nanogenes Free from Man-Made Materials for Host-Specific Transfection and Bio-Aided MR Imaging.

    Science.gov (United States)

    Zhu, Jing-Yi; Zhang, Ming-Kang; Ding, Xian-Guang; Qiu, Wen-Xiu; Yu, Wu-Yang; Feng, Jun; Zhang, Xian-Zheng

    2018-04-20

    Many viruses have a lipid envelope derived from the host cell membrane that contributes much to the host specificity and the cellular invasion. This study puts forward a virus-inspired technology that allows targeted genetic delivery free from man-made materials. Genetic therapeutics, metal ions, and biologically derived cell membranes are nanointegrated. Vulnerable genetic therapeutics contained in the formed "nanogene" can be well protected from unwanted attacks by blood components and enzymes. The surface envelope composed of cancer cell membrane fragments enables host-specific targeting of the nanogene to the source cancer cells and homologous tumors while effectively inhibiting recognition by macrophages. High transfection efficiency highlights the potential of this technology for practical applications. Another unique merit of this technology arises from the facile combination of special biofunction of metal ions with genetic therapy. Typically, Gd(III)-involved nanogene generates a much higher T 1 relaxation rate than the clinically used Gd magnetic resonance imaging agent and harvests the enhanced MRI contrast at tumors. This virus-inspired technology points out a distinctive new avenue for the disease-specific transport of genetic therapeutics and other biomacromolecules. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Predicting fecal sources in waters with diverse pollution loads using general and molecular host-specific indicators and applying machine learning methods.

    Science.gov (United States)

    Casanovas-Massana, Arnau; Gómez-Doñate, Marta; Sánchez, David; Belanche-Muñoz, Lluís A; Muniesa, Maite; Blanch, Anicet R

    2015-03-15

    In this study we use a machine learning software (Ichnaea) to generate predictive models for water samples with different concentrations of fecal contamination (point source, moderate and low). We applied several MST methods (host-specific Bacteroides phages, mitochondrial DNA genetic markers, Bifidobacterium adolescentis and Bifidobacterium dentium markers, and bifidobacterial host-specific qPCR), and general indicators (Escherichia coli, enterococci and somatic coliphages) to evaluate the source of contamination in the samples. The results provided data to the Ichnaea software, that evaluated the performance of each method in the different scenarios and determined the source of the contamination. Almost all MST methods in this study determined correctly the origin of fecal contamination at point source and in moderate concentration samples. When the dilution of the fecal pollution increased (below 3 log10 CFU E. coli/100 ml) some of these indicators (bifidobacterial host-specific qPCR, some mitochondrial markers or B. dentium marker) were not suitable because their concentrations decreased below the detection limit. Using the data from source point samples, the software Ichnaea produced models for waters with low levels of fecal pollution. These models included some MST methods, on the basis of their best performance, that were used to determine the source of pollution in this area. Regardless the methods selected, that could vary depending on the scenario, inductive machine learning methods are a promising tool in MST studies and may represent a leap forward in solving MST cases. Copyright © 2015 Elsevier Ltd. All rights reserved.

  16. NleB/SseK effectors fromCitrobacter rodentium,Escherichia coli, andSalmonella entericadisplay distinct differences in host substrate specificity.

    Science.gov (United States)

    El Qaidi, Samir; Chen, Kangming; Halim, Adnan; Siukstaite, Lina; Rueter, Christian; Hurtado-Guerrero, Ramon; Clausen, Henrik; Hardwidge, Philip R

    2017-07-07

    Many Gram-negative bacterial pathogens use a syringe-like apparatus called a type III secretion system to inject virulence factors into host cells. Some of these effectors are enzymes that modify host proteins to subvert their normal functions. NleB is a glycosyltransferase that modifies host proteins with N -acetyl-d-glucosamine to inhibit antibacterial and inflammatory host responses. NleB is conserved among the attaching/effacing pathogens enterohemorrhagic Escherichia coli (EHEC), enteropathogenic E. coli (EPEC), and Citrobacter rodentium Moreover, Salmonella enterica strains encode up to three NleB orthologs named SseK1, SseK2, and SseK3. However, there are conflicting reports regarding the activities and host protein targets among the NleB/SseK orthologs. Therefore, here we performed in vitro glycosylation assays and cell culture experiments to compare the activities and substrate specificities of these effectors. SseK1, SseK3, EHEC NleB1, EPEC NleB1, and C rodentium NleB blocked TNF-mediated NF-κB pathway activation, whereas SseK2 and NleB2 did not. C. rodentium NleB, EHEC NleB1, and SseK1 glycosylated host GAPDH. C. rodentium NleB, EHEC NleB1, EPEC NleB1, and SseK2 glycosylated the FADD (Fas-associated death domain protein). SseK3 and NleB2 were not active against either substrate. We also found that EHEC NleB1 glycosylated two GAPDH arginine residues, Arg 197 and Arg 200 , and that these two residues were essential for GAPDH-mediated activation of TNF receptor-associated factor 2 ubiquitination. These results provide evidence that members of this highly conserved family of bacterial virulence effectors target different host protein substrates and exhibit distinct cellular modes of action to suppress host responses. © 2017 by The American Society for Biochemistry and Molecular Biology, Inc.

  17. Hidden diversity and host specificity in cycliophorans; a phylogeographic analysis along the North Atlantic and Mediterranean Sea

    DEFF Research Database (Denmark)

    Obst, Matthias; Funch, Peter; Gonzalo, Giribet

    2005-01-01

    .0504). However, itwas low for commensals onNephrops norvegicus(6 haplotypes,h= 0.3899, ππ= 0.0035), andintermediate for cycliophorans onHomarus gammarus(5 haplotypes,h= 0.3020, ππ= 0.0140).Although two of the host lobsters co-inhabit the coastal waters of Europe, a strong geneticstructure (78.45% of the observed...... ability of the cycliophoranchordoid larva. Demographic and phylogenetic analyses suggest old and possibly crypticpopulations present onH. americanusandH. gammarus, while the latter may have experiencedrecent bottlenecks, perhaps during Pleistocene glaciations. Populations onN. norvegicusappear...

  18. Use of lice to identify cowbird hosts

    Science.gov (United States)

    Hahn, D.C.; Price, R.D.; Osenton, P.C.

    2000-01-01

    The host specificity of avian lice (Phthiraptera) may be utilized by biologists to investigate the brood parasitism patterns of Brown-headed Cowbirds (Molothrus ater). As nestlings, brood parasites have a unique opportunity to encounter lice that are typically host specific. Lice are permanent hemimetabolic ectoparasites, a group found strictly on the body of the host, and they are transferred almost exclusively by bodily contact between hosts during care of young and at copulation. We investigated whether cowbird nestlings become infested with avian lice from their host parents and carry these lice away when they fledge, in effect bearing ectoparasite indicators of the species that raised them. The technique of examining the lice on cowbird fledglings to identify their foster parents would be much less costly than hiring a team of experts to determine parasitism patterns in the conventional way by finding hundreds of songbird nests. We examined 244 cowbird fledglings and found that they carried a rich fauna of lice representing 11 species and six genera, almost the entire spectrum of louse genera known to occur on passerines. We also examined 320 songbirds from 30 species, all known hosts of the Brown-headed Cowbird. As a group the host birds bore a diversity of louse species comparable to that on the fledgling cowbirds: 13 species of lice from seven genera. In contrast, most individual passerine host species yielded only 1 or 2 louse species, significantly fewer than the cowbird fledglings (p parasitism patterns. The incomplete state of passerine louse taxonomy requires anyone using this technique to de-louse both cowbird fledglings and local host species in order to have a reference collection of lice. Lice from cowbird fledglings can be identified by a skilled taxonomist and linked to particular host species, and the principal difficulty is the scarcity of skilled avian louse taxonomists. We also found an unusually rich louse fauna on 219 adult cowbirds, which

  19. Molecular approaches identify known species, reveal cryptic species and verify host specificity of Chinese Philotrypesis (Hymenoptera: Pteromalidae).

    Science.gov (United States)

    Zhou, Mei-Jiao; Xiao, Jin-Hua; Bian, Sheng-Nan; Li, Yan-Wei; Niu, Li-Ming; Hu, Hao-Yuan; Wu, Wen-Shan; Murphy, Robert W; Huang, Da-Wei

    2012-07-01

    Philotrypesis, a major component of the fig wasp community (Hymenoptera: Pteromalidae), is a model taxon for studying male fighting and mating behaviour. Its extreme sexual dimorphism and male polymorphism render species identification uncertain and in-depth research on its ecology, behaviour and other evolutionary topics challenging. The fig wasps' enclosed habitat within the syconia makes their mating behaviour inaccessible, to the extent of matching conspecific females and males. In this study, we combine morphological and molecular analyses to identify species of Philotrypesis sampled from south China and to associate their extraordinarily dimorphic genders and labile male morphologies. Morphological evaluations of females identify 22 species and 28 male morphs. The mitochondrial cytochrome c oxidase I and nuclear internal transcribed spacer 2 data detect 21 species using females, and 15 species among the males. Most of the males match the species as delimited by females. Both markers reveal cryptic species in P. quadrisetosa on Ficus vasculosa. Most species of wasps live on one species of fig but three species co-occur in two hosts (F. microcarpa and F. benjamina), which indicates host switching. © 2012 Blackwell Publishing Ltd.

  20. Innate immunity in HIV-1 infection: epithelial and non-specific host factors of mucosal immunity- a workshop report.

    Science.gov (United States)

    Nittayananta, W; Weinberg, A; Malamud, D; Moyes, D; Webster-Cyriaque, J; Ghosh, S

    2016-04-01

    The interplay between HIV-1 and epithelial cells represents a critical aspect in mucosal HIV-1 transmission. Epithelial cells lining the oral cavity cover subepithelial tissues, which contain virus-susceptible host cells including CD4(+) T lymphocytes, monocytes/macrophages, and dendritic cells. Oral epithelia are among the sites of first exposure to both cell-free and cell-associated virus HIV-1 through breast-feeding and oral-genital contact. However, oral mucosa is considered to be naturally resistant to HIV-1 transmission. Oral epithelial cells have been shown to play a crucial role in innate host defense. Nevertheless, it is not clear to what degree these local innate immune factors contribute to HIV-1 resistance of the oral mucosa. This review paper addressed the following issues that were discussed at the 7th World Workshop on Oral Health and Disease in AIDS held in Hyderabad, India, during November 6-9, 2014: (i) What is the fate of HIV-1 after interactions with oral epithelial cells?; (ii) What are the keratinocyte and other anti-HIV effector oral factors, and how do they contribute to mucosal protection?; (iii) How can HIV-1 interactions with oral epithelium affect activation and populations of local immune cells?; (iv) How can HIV-1 interactions alter functions of oral epithelial cells? © 2016 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  1. Brucella TIR-like protein TcpB/Btp1 specifically targets the host adaptor protein MAL/TIRAP to promote infection.

    Science.gov (United States)

    Li, Wenna; Ke, Yuehua; Wang, Yufei; Yang, Mingjuan; Gao, Junguang; Zhan, Shaoxia; Xinying, Du; Huang, Liuyu; Li, Wenfeng; Chen, Zeliang; Li, Juan

    2016-08-26

    Brucella spp. are known to avoid host immune recognition and weaken the immune response to infection. Brucella like accomplish this by employing two clever strategies, called the stealth strategy and hijacking strategy. The TIR domain-containing protein (TcpB/Btp1) of Brucella melitensis is thought to be involved in inhibiting host NF-κB activation by binding to adaptors downstream of Toll-like receptors. However, of the five TIR domain-containing adaptors conserved in mammals, whether MyD88 or MAL, even other three adaptors, are specifically targeted by TcpB has not been identified. Here, we confirmed the effect of TcpB on B.melitensis virulence in mice and found that TcpB selectively targets MAL. By using siRNA against MAL, we found that TcpB from B.melitensis is involved in intracellular survival and that MAL affects intracellular replication of B.melitensis. Our results confirm that TcpB specifically targets MAL/TIRAP to disrupt downstream signaling pathways and promote intra-host survival of Brucella spp. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Host Specificity of Epiplema albida: A Potential Biological Control Agent for Sri Lankan Privet in the Mascarene Islands

    Directory of Open Access Journals (Sweden)

    Richard H. Shaw

    2017-07-01

    Full Text Available Epiplema albida (Hampson (Lepidoptera: Uraniidae, Epipleminae from Sri Lanka, was studied to assess its safety for use as a biological control agent for Sri Lankan privet, Ligustrum robustum subsp. walkeri (Oleaceae in La Réunion and other Mascarene Islands. Larval no-choice feeding tests using newly hatched larvae, larval development tests, and multiple choice oviposition tests were used. Adult females of E. albida are shown to have highly selective oviposition behaviour and the species is physiologically restricted to very few hosts for feeding and development. The risk to key test plants in La Réunion is minimal, so this species can be considered for use as a biological control agent there, but would need further evaluation for potential use elsewhere.

  3. The structures of bacteriophages K1E and K1-5 explain processive degradation of polysaccharide capsules and evolution of new host specificities.

    Science.gov (United States)

    Leiman, Petr G; Battisti, Anthony J; Bowman, Valorie D; Stummeyer, Katharina; Mühlenhoff, Martina; Gerardy-Schahn, Rita; Scholl, Dean; Molineux, Ian J

    2007-08-17

    External polysaccharides of many pathogenic bacteria form capsules protecting the bacteria from the animal immune system and phage infection. However, some bacteriophages can digest these capsules using glycosidases displayed on the phage particle. We have utilized cryo-electron microscopy to determine the structures of phages K1E and K1-5 and thereby establish the mechanism by which these phages attain and switch their host specificity. Using a specific glycosidase, both phages penetrate the capsule and infect the neuroinvasive human pathogen Escherichia coli K1. In addition to the K1-specific glycosidase, each K1-5 particle carries a second enzyme that allows it to infect E. coli K5, whose capsule is chemically different from that of K1. The enzymes are organized into a multiprotein complex attached via an adapter protein to the virus portal vertex, through which the DNA is ejected during infection. The structure of the complex suggests a mechanism for the apparent processivity of degradation that occurs as the phage drills through the polysaccharide capsule. The enzymes recognize the adapter protein by a conserved N-terminal sequence, providing a mechanism for phages to acquire different enzymes and thus to evolve new host specificities.

  4. Lineage-specific serology confirms Brazilian Atlantic forest lion tamarins, Leontopithecus chrysomelas and Leontopithecus rosalia, as reservoir hosts of Trypanosoma cruzi II (TcII).

    Science.gov (United States)

    Kerr, Charlotte L; Bhattacharyya, Tapan; Xavier, Samanta C C; Barros, Juliana H; Lima, Valdirene S; Jansen, Ana M; Miles, Michael A

    2016-11-15

    Trypanosoma cruzi, the agent of Chagas disease in humans, has a vast reservoir of mammalian hosts in the Americas, and is classified into six genetic lineages, TcI-TcVI, with a possible seventh, TcBat. Elucidating enzootic cycles of the different lineages is important for understanding the ecology of this parasite, the emergence of new outbreaks of Chagas disease and for guiding control strategies. Direct lineage identification by genotyping is hampered by limitations of parasite isolation and culture. An indirect method is to identify lineage-specific serological reactions in infected individuals; here we describe its application with sylvatic Brazilian primates. Synthetic peptides representing lineage-specific epitopes of the T. cruzi surface protein TSSA were used in ELISA with sera from Atlantic Forest Leontopithecus chrysomelas (golden-headed lion tamarin), L. rosalia (golden lion tamarin), Amazonian Sapajus libidinosus (black-striped capuchin) and Alouatta belzebul (red-handed howler monkey). The epitope common to lineages TcII, TcV and TcVI was recognised by sera from 15 of 26 L. chrysomelas and 8 of 13 L. rosalia. For 12 of these serologically identified TcII infections, the identity of the lineage infection was confirmed by genotyping T. cruzi isolates. Of the TcII/TcV/TcVI positive sera 12 of the 15 L. chrysomelas and 2 of the 8 L. rosalia also reacted with the specific epitope restricted to TcV and TcVI. Sera from one of six S. libidinous recognised the TcIV/TcIII epitopes. This lineage-specific serological surveillance has verified that Atlantic Forest primates are reservoir hosts of at least TcII, and probably TcV and TcVI, commonly associated with severe Chagas disease in the southern cone region of South America. With appropriate reagents, this novel methodology is readily applicable to a wide range of mammal species and reservoir host discovery.

  5. Contrasting root associated fungi of three common oak-woodland plant species based on molecular identification: host specificity or non-specific amplification?

    Science.gov (United States)

    Douhan, Greg W; Petersen, Carolyn; Bledsoe, Caroline S; Rizzo, David M

    2005-07-01

    An increasingly popular approach used to identify arbuscular mycorrhizal (AM) fungi in planta is to amplify a portion of AM fungal small subunit ribosomal DNA (SSU-rDNA) from whole root DNA extractions using the primer pair AM1-NS31, followed by cloning and sequencing. We used this approach to study the AM fungal community composition of three common oak-woodland plant species: a grass (Cynosurus echinatus), blue oak (Quercus douglasii), and a forb (Torilis arvensis). Significant diversity of AM fungi were found in the roots of C. echinatus, which is consistent with previous studies demonstrating a high degree of AM fungal diversity from the roots of various hosts. In contrast, clones from Q. douglasii and T. arvensis were primarily from non-AM fungi of diverse origins within the Ascomycota and Basidiomycota. This work demonstrates that caution must be taken when using this molecular approach to determine in planta AM fungal diversity if non-sequence based methods such as terminal restriction fragment length polymorphisms, denaturing gradient gel electrophoresis, or temperature gradient gel electrophoresis are used.

  6. Fluorescence properties and sequestration of peripheral anionic site specific ligands in bile acid hosts: Effect on acetylcholinesterase inhibition activity.

    Science.gov (United States)

    Islam, Mullah Muhaiminul; Aguan, Kripamoy; Mitra, Sivaprasad

    2016-05-01

    The increase in fluorescence intensity of model acetyl cholinesterase (AChE) inhibitors like propidium iodide (PI) and ethidium bromide (EB) is due to sequestration of the probes in primary micellar aggregates of bile acid (BA) host medium with moderate binding affinity of ca. 10(2)-10(3)M(-1). Multiple regression analysis of solvent dependent fluorescence behavior of PI indicates the decrease in total nonradiative decay rate due to partial shielding of the probe from hydrogen bond donation ability of the aqueous medium in bile acid bound fraction. Both PI and EB affects AChE activity through mixed inhibition and consistent with one site binding model; however, PI (IC50=20±1μM) shows greater inhibition in comparison with EB (IC50=40±3μM) possibly due to stronger interaction with enzyme active site. The potency of AChE inhibition for both the compounds is drastically reduced in the presence of bile acid due to the formation of BA-inhibitor complex and subsequent reduction of active inhibitor fraction in the medium. Although the inhibition mechanism still remains the same, the course of catalytic reaction critically depends on equilibrium binding among several species present in the solution; particularly at low inhibitor concentration. All the kinetic parameters for enzyme inhibition reaction are nicely correlated with the association constant for BA-inhibitor complex formation. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. The C-terminus of Wheat streak mosaic virus coat protein is involved in differential infection of wheat and maize through host-specific long-distance transport.

    Science.gov (United States)

    Tatineni, Satyanarayana; French, Roy

    2014-02-01

    Viral determinants and mechanisms involved in extension of host range of monocot-infecting viruses are poorly understood. Viral coat proteins (CP) serve many functions in almost every aspect of the virus life cycle. The role of the C-terminal region of Wheat streak mosaic virus (WSMV) CP in virus biology was examined by mutating six negatively charged aspartic acid residues at positions 216, 289, 290, 326, 333, and 334. All of these amino acid residues are dispensable for virion assembly, and aspartic acid residues at positions 216, 333, and 334 are expendable for normal infection of wheat and maize. However, mutants D289N, D289A, D290A, DD289/290NA, and D326A exhibited slow cell-to-cell movement in wheat, which resulted in delayed onset of systemic infection, followed by a rapid recovery of genomic RNA accumulation and symptom development. Mutants D289N, D289A, and D326A inefficiently infected maize, eliciting milder symptoms, while D290A and DD289/290NA failed to infect systemically, suggesting that the C-terminus of CP is involved in differential infection of wheat and maize. Mutation of aspartic acid residues at amino acid positions 289, 290, and 326 severely debilitated virus ingress into the vascular system of maize but not wheat, suggesting that these amino acids facilitate expansion of WSMV host range through host-specific long-distance transport.

  8. Dual-label flow cytometry-based host cell adhesion assay to ascertain the prospect of probiotic Lactobacillus plantarum in niche-specific antibacterial therapy.

    Science.gov (United States)

    Mukherjee, Sandipan; Ramesh, Aiyagari

    2017-12-01

    Host cell adhesion assays that provide quantitative insight on the potential of lactic acid bacteria (LAB) to inhibit adhesion of intestinal pathogens can be leveraged for the development of niche-specific anti-adhesion therapy. Herein, we report a dual-colour flow cytometry (FCM) analysis to assess the ability of probiotic Lactobacillus plantarum strains to impede adhesion of Enterococcus faecalis, Listeria monocytogenes and Staphylococcus aureus onto HT-29 cells. FCM in conjunction with a hierarchical cluster analysis could discern the anti-adhesion potential of L. plantarum strains, wherein the efficacy of L. plantarum DF9 was on a par with the probiotic L. rhamnosus GG. Combination of FCM with principal component analysis illustrated the relative influence of LAB strains on adhesion parameters kd and em of the pathogen and identified probiotic LAB suitable for anti-adhesion intervention. The analytical merit of the FCM analysis was captured in host cell adhesion assays that measured relative elimination of adhered LAB vis-à-vis pathogens, on exposure to either LAB bacteriocins or therapeutic antibiotics. It is envisaged that the dual-colour FCM-based adhesion assay described herein would enable a fundamental understanding of the host cell adhesion process and stimulate interest in probiotic LAB as safe anti-adhesion therapeutic agents against gastrointestinal pathogens.

  9. Comparative Proteomics Reveals Strain-Specific β-TrCP Degradation via Rotavirus NSP1 Hijacking a Host Cullin-3-Rbx1 Complex.

    Directory of Open Access Journals (Sweden)

    Siyuan Ding

    2016-10-01

    Full Text Available Rotaviruses (RVs are the leading cause of severe gastroenteritis in young children, accounting for half a million deaths annually worldwide. RV encodes non-structural protein 1 (NSP1, a well-characterized interferon (IFN antagonist, which facilitates virus replication by mediating the degradation of host antiviral factors including IRF3 and β-TrCP. Here, we utilized six human and animal RV NSP1s as baits and performed tandem-affinity purification coupled with high-resolution mass spectrometry to comprehensively characterize NSP1-host protein interaction network. Multiple Cullin-RING ubiquitin ligase (CRL complexes were identified. Importantly, inhibition of cullin-3 (Cul3 or RING-box protein 1 (Rbx1, by siRNA silencing or chemical perturbation, significantly impairs strain-specific NSP1-mediated β-TrCP degradation. Mechanistically, we demonstrate that NSP1 localizes to the Golgi with the host Cul3-Rbx1 CRL complex, which targets β-TrCP and NSP1 for co-destruction at the proteasome. Our study uncovers a novel mechanism that RV employs to promote β-TrCP turnover and provides molecular insights into virus-mediated innate immunity inhibition.

  10. Relaxation Methods for Strictly Convex Regularizations of Piecewise Linear Programs

    International Nuclear Information System (INIS)

    Kiwiel, K. C.

    1998-01-01

    We give an algorithm for minimizing the sum of a strictly convex function and a convex piecewise linear function. It extends several dual coordinate ascent methods for large-scale linearly constrained problems that occur in entropy maximization, quadratic programming, and network flows. In particular, it may solve exact penalty versions of such (possibly inconsistent) problems, and subproblems of bundle methods for nondifferentiable optimization. It is simple, can exploit sparsity, and in certain cases is highly parallelizable. Its global convergence is established in the recent framework of B -functions (generalized Bregman functions)

  11. Novel IgG-Degrading Enzymes of the IgdE Protease Family Link Substrate Specificity to Host Tropism of Streptococcus Species.

    Science.gov (United States)

    Spoerry, Christian; Hessle, Pontus; Lewis, Melanie J; Paton, Lois; Woof, Jenny M; von Pawel-Rammingen, Ulrich

    2016-01-01

    Recently we have discovered an IgG degrading enzyme of the endemic pig pathogen S. suis designated IgdE that is highly specific for porcine IgG. This protease is the founding member of a novel cysteine protease family assigned C113 in the MEROPS peptidase database. Bioinformatical analyses revealed putative members of the IgdE protease family in eight other Streptococcus species. The genes of the putative IgdE family proteases of S. agalactiae, S. porcinus, S. pseudoporcinus and S. equi subsp. zooepidemicus were cloned for production of recombinant protein into expression vectors. Recombinant proteins of all four IgdE family proteases were proteolytically active against IgG of the respective Streptococcus species hosts, but not against IgG from other tested species or other classes of immunoglobulins, thereby linking the substrate specificity to the known host tropism. The novel IgdE family proteases of S. agalactiae, S. pseudoporcinus and S. equi showed IgG subtype specificity, i.e. IgdE from S. agalactiae and S. pseudoporcinus cleaved human IgG1, while IgdE from S. equi was subtype specific for equine IgG7. Porcine IgG subtype specificities of the IgdE family proteases of S. porcinus and S. pseudoporcinus remain to be determined. Cleavage of porcine IgG by IgdE of S. pseudoporcinus is suggested to be an evolutionary remaining activity reflecting ancestry of the human pathogen to the porcine pathogen S. porcinus. The IgG subtype specificity of bacterial proteases indicates the special importance of these IgG subtypes in counteracting infection or colonization and opportunistic streptococci neutralize such antibodies through expression of IgdE family proteases as putative immune evasion factors. We suggest that IgdE family proteases might be valid vaccine targets against streptococci of both human and veterinary medical concerns and could also be of therapeutic as well as biotechnological use.

  12. Distinct Metabolic Requirements of Exhausted and Functional Virus-Specific CD8 T Cells in the Same Host

    Directory of Open Access Journals (Sweden)

    Anna Schurich

    2016-08-01

    Full Text Available T cells undergo profound metabolic changes to meet the increased energy demands of maintaining an antiviral response. We postulated that differences in metabolic reprogramming would shape the efficacy of CD8 T cells mounted against persistent viral infections. We found that the poorly functional PD-1hi T cell response against hepatitis B virus (HBV had upregulated the glucose transporter, Glut1, an effect recapitulated by oxygen deprivation to mimic the intrahepatic environment. Glut1hi HBV-specific T cells were dependent on glucose supplies, unlike the more functional cytomegalovirus (CMV-specific T cells that could utilize oxidative phosphorylation in the absence of glucose. The inability of HBV-specific T cells to switch to oxidative phosphorylation was accompanied by increased mitochondrial size and lower mitochondrial potential, indicative of mitochondrial dysfunction. Interleukin (IL-12, which recovers HBV-specific T cell effector function, increased their mitochondrial potential and reduced their dependence on glycolysis. Our findings suggest that mitochondrial defects limit the metabolic plasticity of exhausted HBV-specific T cells.

  13. Variations in attack behaviours between Glossina palpalis gambiensis and G. tachinoides in a gallery forest suggest host specificity.

    Science.gov (United States)

    Salou, E; Rayaisse, J B; Kaba, D; Djohan, V; Yoni, W; Barry, I; Dofini, F; Bouyer, J; Solano, P

    2016-12-01

    Tsetse flies Glossina palpalis gambiensis and G. tachinoides are among the major vectors of sleeping sickness (Human African Trypanosomiasis-HAT) and nagana (African Animal Trypanosomiasis - AAT) in West Africa. Both riparian species occur sympatrically in gallery forests of south west Burkina Faso, but little is known of their interspecies relationships although different authors think there may be some competition between them. The aim of this study was to check if sympatric species have different strategies when approaching a host. A man placed in a sticky cube (1 m × 1 m × 1 m) and a sticky black-blue-black target (1 m × 1 m) were used to capture tsetse along the Comoe river banks in a Latin Square design. The number and the height at which tsetse were caught by each capture method were recorded according to species and sex. Glossina p. gambiensis was more attracted to human bait than to the target, but both species were captured at a significantly higher height on the target compared with the human bait (P  0.05). However, catches on human bait showed a significant difference in height between G. tachinoides and G. p. gambiensis (22.5 and 30.6 cm, respectively, P < 0.001). This study showed that these sympatric species had different attack behaviours to humans, which is not the case with the target. The implications of these findings are discussed. © 2016 The Royal Entomological Society.

  14. The population genetics of Pseudomonas aeruginosa isolates from different patient populations exhibits high-level host specificity

    NARCIS (Netherlands)

    van Mansfeld, R.; Jongerden, I.P.; Bootsma, M.C.; Buiting, A.; Bonten, M.J.M.; Willems, R.J.L.

    2010-01-01

    Objective To determine whether highly prevalent P. aeruginosa sequence types (ST) in Dutch cystic fibrosis (CF) patients are specifically linked to CF patients we investigated the population structure of P. aeruginosa from different clinical backgrounds. We first selected the optimal genotyping

  15. How Specific is Non-Hypersensitive Host and Nonhost Resistance of Barley to Rust and Mildew Fungi?

    NARCIS (Netherlands)

    Niks, R.E.

    2014-01-01

    Full nonhost resistance can be defined as immunity, displayed by an entire plant species against all genotypes of a plant pathogen. Interesting biological questions are, whether the genes responsible for the nonhost status of a plant species have a general or a specific effectiveness to heterologous

  16. Non-strictly black body spectrum from the tunnelling mechanism

    International Nuclear Information System (INIS)

    Corda, Christian

    2013-01-01

    The tunnelling mechanism is widely used to explain Hawking radiation. However, in many cases the analysis used to obtain the Hawking temperature only involves comparing the emission probability for an outgoing particle with the Boltzmann factor. Banerjee and Majhi improved this approach by explicitly finding a black body spectrum associated with black holes. Their result, obtained using a reformulation of the tunnelling mechanism, is in contrast to that of Parikh and Wilczek, who found an emission probability that is compatible with a non-strictly thermal spectrum. Using the recently identified effective state for a black hole, we solve this contradiction via a slight modification of the analysis by Banerjee and Majhi. The final result is a non-strictly black body spectrum from the tunnelling mechanism. We also show that for an effective temperature, we can express the corresponding effective metric using Hawking’s periodicity arguments. Potential important implications for the black hole information puzzle are discussed. -- Highlights: •We review an important result by Banerjee and Majhi on the tunnelling mechanism in the framework of Hawking radiation. •This result is in contrast to another result reported by Parikh and Wilczek. •We introduce the effective state of a black hole. •We explain the contrast via a slight modification of the analysis by Banerjee and Majhi. •We discuss potential important implications for the black hole information puzzle

  17. The population genetics of Pseudomonas aeruginosa isolates from different patient populations exhibits high-level host specificity.

    Directory of Open Access Journals (Sweden)

    Rosa van Mansfeld

    Full Text Available OBJECTIVE: To determine whether highly prevalent P. aeruginosa sequence types (ST in Dutch cystic fibrosis (CF patients are specifically linked to CF patients we investigated the population structure of P. aeruginosa from different clinical backgrounds. We first selected the optimal genotyping method by comparing pulsed-field gel electrophoresis (PFGE, multilocus sequence typing (MLST and multilocus variable number tandem-repeat analysis (MLVA. METHODS: Selected P. aeruginosa isolates (n = 60 were genotyped with PFGE, MLST and MLVA to determine the diversity index (DI and congruence (adjusted Rand and Wallace coefficients. Subsequently, isolates from patients admitted to two different ICUs (n = 205, from CF patients (n = 100 and from non-ICU, non-CF patients (n = 58, of which 19 were community acquired were genotyped with MLVA to determine distribution of genotypes and genetic diversity. RESULTS: Congruence between the typing methods was >79% and DIs were similar and all >0.963. Based on costs, ease, speed and possibilities to compare results between labs an adapted MLVA scheme called MLVA9-Utrecht was selected as the preferred typing method. In 363 clinical isolates 252 different MLVA types (MTs were identified, indicating a highly diverse population (DI  = 0.995; CI  = 0.993-0.997. DI levels were similarly high in the diverse clinical sources (all >0.981 and only eight genotypes were shared. MTs were highly specific (>80% for the different patient populations, even for similar patient groups (ICU patients in two distinct geographic regions, with only three of 142 ICU genotypes detected in both ICUs. The two major CF clones were unique to CF patients. CONCLUSION: The population structure of P. aeruginosa isolates is highly diverse and population specific without evidence for a core lineage in which major CF, hospital or community clones co-cluster. The two genotypes highly prevalent among Dutch CF patients appeared unique to CF patients

  18. Host Ranges of Listeria-Specific Bacteriophages from the Turkey Processing Plant Environment in the United States ▿

    OpenAIRE

    Kim, Jae-Won; Siletzky, Robin M.; Kathariou, Sophia

    2008-01-01

    Even though at least 400 Listeria phages have been isolated from various sources, limited information is available on phages from the food processing plant environment. Phages in the processing plant environment may play critical roles in determining the Listeria population that becomes established in the plant. In this study, we pursued the isolation of Listeria-specific phages from environmental samples from four turkey processing plants in the United States. These environmental samples wer...

  19. Site-specific deletions of chromosomally located DNA segments with the multimer resolution system of broad-host-range plasmid RP4

    DEFF Research Database (Denmark)

    Sternberg, Claus; Eberl, Leo; Sanchezromero, Juan M.

    1995-01-01

    The multimer resolution system (mrs) of the broad-host-range plasmid RP4 has been exploited to develop a general method that permits the precise excision of chromosomal segments in a variety of gram-negative bacteria. The procedure is based on the site-specific recombination between two directly...... of the parA expression system suggested that just a few molecules of the resolvase are required to achieve the site-specific recombination event, Transient expression of parA from a plasmid unable to replicate in the target bacterium was instrumental to effect differential deletions within complex hybrid...... transposons inserted in the chromosome of Pseudomonas putida, This strategy permits the stable inheritance of heterologous DNA segments virtually devoid of the sequences used initially to select their insertion....

  20. Host virus and pneumococcus-specific immune responses in high-count monoclonal B-cell lymphocytosis and chronic lymphocytic leukemia: implications for disease progression.

    Science.gov (United States)

    Criado, Ignacio; Muñoz-Criado, Santiago; Rodríguez-Caballero, Arancha; Nieto, Wendy G; Romero, Alfonso; Fernández-Navarro, Paulino; Alcoceba, Miguel; Contreras, Teresa; González, Marcos; Orfao, Alberto; Almeida, Julia

    2017-07-01

    Patients diagnosed with chronic lymphocytic leukemia (CLL) display a high incidence of infections due to an associated immunodeficiency that includes hypogammaglobulinemia. A higher risk of infections has also been recently reported for high-count monoclonal B-cell lymphocytosis, while no information is available in low-count monoclonal B-cell lymphocytosis. Here, we evaluated the status of the humoral immune system in patients with chronic lymphocytic leukemia (n=58), as well as in low- (n=71) and high- (n=29) count monoclonal B-cell lymphocytosis versus healthy donors (n=91). Total free plasma immunoglobulin titers and specific levels of antibodies against cytomegalovirus, Epstein-Barr virus, influenza and S.pneumoniae were measured by nephelometry and ELISA-based techniques, respectively. Overall, our results show that both CLL and high-count monoclonal B-cell lymphocytosis patients, but not low-count monoclonal B-cell lymphocytosis subjects, present with relatively high levels of antibodies specific for the latent viruses investigated, associated with progressively lower levels of S.pneumoniae -specific immunoglobulins. These findings probably reflect asymptomatic chronic reactivation of humoral immune responses against host viruses associated with expanded virus-specific antibody levels and progressively decreased protection against other micro-organisms, denoting a severe humoral immunodeficiency state not reflected by the overall plasma immunoglobulin levels. Alternatively, these results could reflect a potential role of ubiquitous viruses in the pathogenesis of the disease. Further analyses are necessary to establish the relevance of such asymptomatic humoral immune responses against host viruses in the expansion of the tumor B-cell clone and progression from monoclonal B-cell lymphocytosis to CLL. Copyright© 2017 Ferrata Storti Foundation.

  1. Tissue-specific and SRSF1-dependent splicing of fibronectin, a matrix protein that controls host cell invasion

    Science.gov (United States)

    Lopez-Mejia, Isabel Cristina; De Toledo, Marion; Della Seta, Flavio; Fafet, Patrick; Rebouissou, Cosette; Deleuze, Virginie; Blanchard, Jean Marie; Jorgensen, Christian; Tazi, Jamal; Vignais, Marie-Luce

    2013-01-01

    Cell invasion targets specific tissues in physiological placental implantation and pathological metastasis, which raises questions about how this process is controlled. We compare dermis and endometrium capacities to support trophoblast invasion, using matching sets of human primary fibroblasts in a coculture assay with human placental explants. Substituting endometrium, the natural trophoblast target, with dermis dramatically reduces trophoblast interstitial invasion. Our data reveal that endometrium expresses a higher rate of the fibronectin (FN) extra type III domain A+ (EDA+) splicing isoform, which displays stronger matrix incorporation capacity. We demonstrate that the high FN content of the endometrium matrix, and not specifically the EDA domain, supports trophoblast invasion by showing that forced incorporation of plasma FN (EDA–) promotes efficient trophoblast invasion. We further show that the serine/arginine-rich protein serine/arginine-rich splicing factor 1 (SRSF1) is more highly expressed in endometrium and, using RNA interference, that it is involved in the higher EDA exon inclusion rate in endometrium. Our data therefore show a mechanism by which tissues can be distinguished, for their capacity to support invasion, by their different rates of EDA inclusion, linked to their SRSF1 protein levels. In the broader context of cancer pathology, the results suggest that SRSF1 might play a central role not only in the tumor cells, but also in the surrounding stroma. PMID:23966470

  2. Day-to-Day Dynamics of Commensal Escherichia coli in Zimbabwean Cows Evidence Temporal Fluctuations within a Host-Specific Population Structure

    Science.gov (United States)

    Massot, Méril; Couffignal, Camille; Clermont, Olivier; D'Humières, Camille; Chatel, Jérémie; Plault, Nicolas; Andremont, Antoine; Mentré, France

    2017-01-01

    ABSTRACT To get insights into the temporal pattern of commensal Escherichia coli populations, we sampled the feces of four healthy cows from the same herd in the Hwange District of Zimbabwe daily over 25 days. The cows had not received antibiotic treatment during the previous 3 months. We performed viable E. coli counts and characterized the 326 isolates originating from the 98 stool samples at a clonal level, screened them for stx and eae genes, and tested them for their antibiotic susceptibilities. We observed that E. coli counts and dominant clones were different among cows, and very few clones were shared. No clone was shared by three or four cows. Clone richness and evenness were not different between cows. Within each host, the variability in the E. coli count was evidenced between days, and no clone was found to be dominant during the entire sampling period, suggesting the existence of clonal interference. Dominant clones tended to persist longer than subdominant ones and were mainly from phylogenetic groups A and B1. Five E. coli clones were found to contain both the stx1 and stx2 genes, representing 6.3% of the studied isolates. All cows harbored at least one Shiga toxin-producing E. coli (STEC) strain. Resistance to tetracycline, penicillins, trimethoprim, and sulfonamides was rare and observed in three clones that were shed at low levels in two cows. This study highlights the fact that the commensal E. coli population, including the STEC population, is host specific, is highly dynamic over a short time frame, and rarely carries antibiotic resistance determinants in the absence of antibiotic treatment. IMPORTANCE The literature about the dynamics of commensal Escherichia coli populations is very scarce. Over 25 days, we followed the total E. coli counts daily and characterized the sampled clones in the feces of four cows from the same herd living in the Hwange District of Zimbabwe. This study deals with the day-to-day dynamics of both quantitative and

  3. Day-to-Day Dynamics of Commensal Escherichia coli in Zimbabwean Cows Evidence Temporal Fluctuations within a Host-Specific Population Structure.

    Science.gov (United States)

    Massot, Méril; Couffignal, Camille; Clermont, Olivier; D'Humières, Camille; Chatel, Jérémie; Plault, Nicolas; Andremont, Antoine; Caron, Alexandre; Mentré, France; Denamur, Erick

    2017-07-01

    To get insights into the temporal pattern of commensal Escherichia coli populations, we sampled the feces of four healthy cows from the same herd in the Hwange District of Zimbabwe daily over 25 days. The cows had not received antibiotic treatment during the previous 3 months. We performed viable E. coli counts and characterized the 326 isolates originating from the 98 stool samples at a clonal level, screened them for stx and eae genes, and tested them for their antibiotic susceptibilities. We observed that E. coli counts and dominant clones were different among cows, and very few clones were shared. No clone was shared by three or four cows. Clone richness and evenness were not different between cows. Within each host, the variability in the E. coli count was evidenced between days, and no clone was found to be dominant during the entire sampling period, suggesting the existence of clonal interference. Dominant clones tended to persist longer than subdominant ones and were mainly from phylogenetic groups A and B1. Five E. coli clones were found to contain both the stx 1 and stx 2 genes, representing 6.3% of the studied isolates. All cows harbored at least one Shiga toxin-producing E. coli (STEC) strain. Resistance to tetracycline, penicillins, trimethoprim, and sulfonamides was rare and observed in three clones that were shed at low levels in two cows. This study highlights the fact that the commensal E. coli population, including the STEC population, is host specific, is highly dynamic over a short time frame, and rarely carries antibiotic resistance determinants in the absence of antibiotic treatment. IMPORTANCE The literature about the dynamics of commensal Escherichia coli populations is very scarce. Over 25 days, we followed the total E. coli counts daily and characterized the sampled clones in the feces of four cows from the same herd living in the Hwange District of Zimbabwe. This study deals with the day-to-day dynamics of both quantitative and

  4. The host plant Pinus pinaster exerts specific effects on phosphate efflux and polyphosphate metabolism of the ectomycorrhizal fungus Hebeloma cylindrosporum: a radiotracer, cytological staining and31P NMR spectroscopy study.

    Science.gov (United States)

    Torres-Aquino, Margarita; Becquer, Adeline; Le Guernevé, Christine; Louche, Julien; Amenc, Laurie K; Staunton, Siobhan; Quiquampoix, Hervé; Plassard, Claude

    2017-02-01

    Ectomycorrhizal (ECM) association can improve plant phosphorus (P) nutrition. Polyphosphates (polyP) synthesized in distant fungal cells after P uptake may contribute to P supply from the fungus to the host plant if they are hydrolyzed to phosphate in ECM roots then transferred to the host plant when required. In this study, we addressed this hypothesis for the ECM fungus Hebeloma cylindrosporum grown in vitro and incubated without plant or with host (Pinus pinaster) and non-host (Zea mays) plants, using an experimental system simulating the symbiotic interface. We used 32 P labelling to quantify P accumulation and P efflux and in vivo and in vitro nuclear magnetic resonance (NMR) spectroscopy and cytological staining to follow the fate of fungal polyP. Phosphate supply triggered a massive P accumulation as newly synthesized long-chain polyP in H. cylindrosporum if previously grown under P-deficient conditions. P efflux from H. cylindrosporum towards the roots was stimulated by both host and non-host plants. However, the host plant enhanced 32 P release compared with the non-host plant and specifically increased the proportion of short-chain polyP in the interacting mycelia. These results support the existence of specific host plant effects on fungal P metabolism able to provide P in the apoplast of ectomycorrhizal roots. © 2016 John Wiley & Sons Ltd.

  5. Lineage-specific serology confirms Brazilian Atlantic forest lion tamarins, Leontopithecus chrysomelas and Leontopithecus rosalia, as reservoir hosts of Trypanosoma cruzi II (TcII

    Directory of Open Access Journals (Sweden)

    Charlotte L. Kerr

    2016-11-01

    Full Text Available Abstract Background Trypanosoma cruzi, the agent of Chagas disease in humans, has a vast reservoir of mammalian hosts in the Americas, and is classified into six genetic lineages, TcI-TcVI, with a possible seventh, TcBat. Elucidating enzootic cycles of the different lineages is important for understanding the ecology of this parasite, the emergence of new outbreaks of Chagas disease and for guiding control strategies. Direct lineage identification by genotyping is hampered by limitations of parasite isolation and culture. An indirect method is to identify lineage-specific serological reactions in infected individuals; here we describe its application with sylvatic Brazilian primates. Methods Synthetic peptides representing lineage-specific epitopes of the T. cruzi surface protein TSSA were used in ELISA with sera from Atlantic Forest Leontopithecus chrysomelas (golden-headed lion tamarin, L. rosalia (golden lion tamarin, Amazonian Sapajus libidinosus (black-striped capuchin and Alouatta belzebul (red-handed howler monkey. Results The epitope common to lineages TcII, TcV and TcVI was recognised by sera from 15 of 26 L. chrysomelas and 8 of 13 L. rosalia. For 12 of these serologically identified TcII infections, the identity of the lineage infection was confirmed by genotyping T. cruzi isolates. Of the TcII/TcV/TcVI positive sera 12 of the 15 L. chrysomelas and 2 of the 8 L. rosalia also reacted with the specific epitope restricted to TcV and TcVI. Sera from one of six S. libidinous recognised the TcIV/TcIII epitopes. Conclusions This lineage-specific serological surveillance has verified that Atlantic Forest primates are reservoir hosts of at least TcII, and probably TcV and TcVI, commonly associated with severe Chagas disease in the southern cone region of South America. With appropriate reagents, this novel methodology is readily applicable to a wide range of mammal species and reservoir host discovery.

  6. Host-specific serological response to Angiostrongylus vasorum infection in red foxes (Vulpes vulpes): implications for parasite epidemiology.

    Science.gov (United States)

    Gillis-Germitsch, N; Kapel, C M O; Thamsborg, S M; Deplazes, P; Schnyder, M

    2017-08-01

    Angiostrongylus vasorum is a cardiovascular nematode increasingly found in dogs and foxes in endemic foci throughout Europe. The present study evaluates ELISAs for detection of circulating antigens and specific antibodies against A. vasorum in foxes. Blood and worm burdens (WBs) from carcasses of 215 Swiss wild red foxes (Vulpes vulpes) and from 75 farmed foxes of different age groups experimentally inoculated once or repeatedly with infective doses of 50, 100 or 200 third-stage larvae were obtained. Antigen detection in the naturally infected Swiss foxes had 91·2% sensitivity and 89·4% specificity, whereas the corresponding figures for antibody detection were 42·2 and 92·0%. The experimentally infected foxes became positive for circulating antigens 5-10 weeks post-inoculation (wpi) and remained highly positive up to 22 wpi, irrespectively of further challenge inoculation. The antibody responses in the same foxes were highly variable: high optical density (OD) values were reached 5-7 wpi in all animals, followed by a decrease in over half of the animals despite accumulating and consequently high WBs resulting in persistent infections. After each challenge, a slight increase of OD values was observed 7 weeks later. We hypothesize that infected foxes develop a variable and non-protective immunity. Such parasite tolerance allows long-term survival of A. vasorum in the animals, and may explain why the parasite appears to spread rapidly within a fox population, an epidemiological dynamic that is evident in many parts of Europe where A. vasorum has been found over the last decades.

  7. Effects of a strict cutoff on Quantum Field Theory

    International Nuclear Information System (INIS)

    Sturnfield, J.F.

    1987-01-01

    Standard Quantum Field Theory has a number of integrals which are infinite. Although these are eliminated for some cases by renormalization, this aspect of the theory is not fully satisfactory. A number of theories with fundamental lengths have been introduced as alternatives and it would be useful to be able to distinguish between them. In particular, the effects that a strict cutoff would have on Quantum Field Theory is studied. It is noted that care must be taken in the method used to apply a strict cutoff. This lead to considering a theory where the cutoffs are defined by restricting each internal line. This theory is only piece-wise analytic. The resulting scattering matrix is frame dependent, yet the theory still satisfies the special relativity view that all frames are subjectively identical. The renormalization of this theory is finite. The change in mass from the electron self-energy will be a spinor operator. The main distinctions of this theory from standard theory will occur at super high energies. New poles and resonances which arise from new endpoint singularities will be found. The locations of these singularities will be frame dependent. Some of these singularities will correspond to creations or interactions of the normal particles with tachyons. It will be shown that for the one loop diagram, the form of the cutoff singularities are closely related to the standard singularities. When there is more than one loop, there can appear some new type of behavior. In particular, a cube root type of behavior in the two loop self-energy diagram will be found. Also the asymptotic behavior of the ladder diagram is studied

  8. Analyses des discours non strictement mathematiques accompagnant des cours de mathematiques (Analysis of Not Strictly Mathematical Discourse in Mathematics Classes).

    Science.gov (United States)

    Robert, Aline

    1995-01-01

    Examines discourse, not strictly mathematical, that teachers might adopt in a mathematics class and presents three major functions of such discourse: communication; structuring and labeling; and reflection. Develops lines for further inquiry, notably on the third function, the most likely focus for specific preparation by the teacher. (13…

  9. Cytological and transcriptional dynamics analysis of host plant revealed stage-specific biological processes related to compatible rice-Ustilaginoidea virens interaction.

    Directory of Open Access Journals (Sweden)

    Jinquan Chao

    Full Text Available Rice false smut, a fungal disease caused by Ustilaginoidea virens is becoming a severe detriment to rice production worldwide. However, little is known about the molecular response of rice to attacks by the smut pathogen. In this article, we define the initial infection process as having three stages: initial colonization on the pistil (stage 1, S1, amplification on the anther (stage 2, S2 and sporulation in the anther chambers (stage 3, S3. Based on the transcriptome of rice hosts in response to U. virens in two separate years, we identified 126, 204, and 580 specific regulated genes in their respective stages S1, S2, and S3, respectively, by excluding common expression patterns in other openly biotic/abiotic databases using bioinformatics. As the disease progresses, several stage-specific biological processes (BP terms were distinctively enriched: "Phosphorylation" in stage S1, "PCD" in S2, and "Cell wall biogenesis" in S3, implying a concise signal cascade indicative of the tactics that smut pathogens use to control host rice cells during infection. 113 regulated genes were coexpressed among the three stages. They shared highly conserved promoter cis-element in the promoters in response to the regulation of WRKY and Myb for up-regulation, and ABA and Ca2+ for down regulation, indicating their potentially critical roles in signal transduction during rice-U. virens interaction. We further analyzed seven highly regulated unique genes; four were specific to pollen development, implying that pollen-related genes play critical roles in the establishment of rice susceptibility to U. virens. To my knowledge, this is the first report about probing of molecular response of rice to smut pathogen infection, which will greatly expand our understanding of the molecular events surrounding infection by rice false smut.

  10. A novel Zika virus mouse model reveals strain specific differences in virus pathogenesis and host inflammatory immune responses.

    Directory of Open Access Journals (Sweden)

    Shashank Tripathi

    2017-03-01

    Full Text Available Zika virus (ZIKV is a mosquito borne flavivirus, which was a neglected tropical pathogen until it emerged and spread across the Pacific Area and the Americas, causing large human outbreaks associated with fetal abnormalities and neurological disease in adults. The factors that contributed to the emergence, spread and change in pathogenesis of ZIKV are not understood. We previously reported that ZIKV evades cellular antiviral responses by targeting STAT2 for degradation in human cells. In this study, we demonstrate that Stat2-/- mice are highly susceptible to ZIKV infection, recapitulate virus spread to the central nervous system (CNS, gonads and other visceral organs, and display neurological symptoms. Further, we exploit this model to compare ZIKV pathogenesis caused by a panel of ZIKV strains of a range of spatiotemporal history of isolation and representing African and Asian lineages. We observed that African ZIKV strains induce short episodes of severe neurological symptoms followed by lethality. In comparison, Asian strains manifest prolonged signs of neuronal malfunctions, occasionally causing death of the Stat2-/- mice. African ZIKV strains induced higher levels of inflammatory cytokines and markers associated with cellular infiltration in the infected brain in mice, which may explain exacerbated pathogenesis in comparison to those of the Asian lineage. Interestingly, viral RNA levels in different organs did not correlate with the pathogenicity of the different strains. Taken together, we have established a new murine model that supports ZIKV infection and demonstrate its utility in highlighting intrinsic differences in the inflammatory response induced by different ZIKV strains leading to severity of disease. This study paves the way for the future interrogation of strain-specific changes in the ZIKV genome and their contribution to viral pathogenesis.

  11. Novel IgG-Degrading Enzymes of the IgdE Protease Family Link Substrate Specificity to Host Tropism of Streptococcus Species.

    Directory of Open Access Journals (Sweden)

    Christian Spoerry

    Full Text Available Recently we have discovered an IgG degrading enzyme of the endemic pig pathogen S. suis designated IgdE that is highly specific for porcine IgG. This protease is the founding member of a novel cysteine protease family assigned C113 in the MEROPS peptidase database. Bioinformatical analyses revealed putative members of the IgdE protease family in eight other Streptococcus species. The genes of the putative IgdE family proteases of S. agalactiae, S. porcinus, S. pseudoporcinus and S. equi subsp. zooepidemicus were cloned for production of recombinant protein into expression vectors. Recombinant proteins of all four IgdE family proteases were proteolytically active against IgG of the respective Streptococcus species hosts, but not against IgG from other tested species or other classes of immunoglobulins, thereby linking the substrate specificity to the known host tropism. The novel IgdE family proteases of S. agalactiae, S. pseudoporcinus and S. equi showed IgG subtype specificity, i.e. IgdE from S. agalactiae and S. pseudoporcinus cleaved human IgG1, while IgdE from S. equi was subtype specific for equine IgG7. Porcine IgG subtype specificities of the IgdE family proteases of S. porcinus and S. pseudoporcinus remain to be determined. Cleavage of porcine IgG by IgdE of S. pseudoporcinus is suggested to be an evolutionary remaining activity reflecting ancestry of the human pathogen to the porcine pathogen S. porcinus. The IgG subtype specificity of bacterial proteases indicates the special importance of these IgG subtypes in counteracting infection or colonization and opportunistic streptococci neutralize such antibodies through expression of IgdE family proteases as putative immune evasion factors. We suggest that IgdE family proteases might be valid vaccine targets against streptococci of both human and veterinary medical concerns and could also be of therapeutic as well as biotechnological use.

  12. Novel IgG-Degrading Enzymes of the IgdE Protease Family Link Substrate Specificity to Host Tropism of Streptococcus Species

    Science.gov (United States)

    Spoerry, Christian; Hessle, Pontus; Lewis, Melanie J.; Paton, Lois; Woof, Jenny M.

    2016-01-01

    Recently we have discovered an IgG degrading enzyme of the endemic pig pathogen S. suis designated IgdE that is highly specific for porcine IgG. This protease is the founding member of a novel cysteine protease family assigned C113 in the MEROPS peptidase database. Bioinformatical analyses revealed putative members of the IgdE protease family in eight other Streptococcus species. The genes of the putative IgdE family proteases of S. agalactiae, S. porcinus, S. pseudoporcinus and S. equi subsp. zooepidemicus were cloned for production of recombinant protein into expression vectors. Recombinant proteins of all four IgdE family proteases were proteolytically active against IgG of the respective Streptococcus species hosts, but not against IgG from other tested species or other classes of immunoglobulins, thereby linking the substrate specificity to the known host tropism. The novel IgdE family proteases of S. agalactiae, S. pseudoporcinus and S. equi showed IgG subtype specificity, i.e. IgdE from S. agalactiae and S. pseudoporcinus cleaved human IgG1, while IgdE from S. equi was subtype specific for equine IgG7. Porcine IgG subtype specificities of the IgdE family proteases of S. porcinus and S. pseudoporcinus remain to be determined. Cleavage of porcine IgG by IgdE of S. pseudoporcinus is suggested to be an evolutionary remaining activity reflecting ancestry of the human pathogen to the porcine pathogen S. porcinus. The IgG subtype specificity of bacterial proteases indicates the special importance of these IgG subtypes in counteracting infection or colonization and opportunistic streptococci neutralize such antibodies through expression of IgdE family proteases as putative immune evasion factors. We suggest that IgdE family proteases might be valid vaccine targets against streptococci of both human and veterinary medical concerns and could also be of therapeutic as well as biotechnological use. PMID:27749921

  13. PCR-TTGE analysis of 16S rRNA from rainbow trout (Oncorhynchus mykiss) gut microbiota reveals host-specific communities of active bacteria.

    Science.gov (United States)

    Navarrete, Paola; Magne, Fabien; Araneda, Cristian; Fuentes, Pamela; Barros, Luis; Opazo, Rafael; Espejo, Romilio; Romero, Jaime

    2012-01-01

    This study assessed the relative contributions of host genetics and diet in shaping the gut microbiota of rainbow trout. Full sibling fish from four unrelated families, each consisting of individuals derived from the mating of one male and one female belonging to a breeding program, were fed diets containing either vegetable proteins or vegetable oils for two months in comparison to a control diet consisting of only fish protein and fish oil. Two parallel approaches were applied on the same samples: transcriptionally active bacterial populations were examined based on RNA analysis and were compared with bacterial populations obtained from DNA analysis. Comparison of temporal temperature gradient gel electrophoresis (TTGE) profiles from DNA and RNA showed important differences, indicating that active bacterial populations were better described by RNA analysis. Results showed that some bacterial groups were significantly (P<0.05) associated with specific families, indicating that microbiota composition may be influenced by the host. In addition, the effect of diet on microbiota composition was dependent on the trout family.

  14. Open-field host specificity test of Gratiana boliviana (Coleoptera: Chrysomelidae), a biological control agent of tropical soda apple (Solanaceae) in the United States

    International Nuclear Information System (INIS)

    Gandolfo, D.; McKay, F.; Medal, J.C.; Cuda, J.P.

    2007-01-01

    An open-field experiment was conducted to assess the suitability of the South American leaf feeding beetle Gratiana boliviana Spaeth for biological control of Solanum viarum Dunal in the USA. An open-field test with eggplant, Solanum melongena L., was conducted on the campus of the University of Buenos Aires, Argentina, and a S. viarum control plot was established 40 km from the campus. One hundred adult beetles were released in each plot at the beginning of the experiment during the vegetative stage of the plants, and forty additional beetles were released in the S. melongena plot at the flowering stage. All the plants in each plot were checked twice a week and the number of adults, immatures, and eggs recorded. Results showed almost a complete rejection of eggplant by G. boliviana. No noticeable feeding damage was ever recorded on eggplant. The experiment was ended when the eggplants started to senesce or were severely damaged by whiteflies and spider mites. The results of this open-field experiment corroborate previous quarantine/laboratory host-specificity tests indicating that a host range expansion of G. boliviana to include eggplant is highly unlikely. Gratiana boliviana was approved for field release in May 2003 in the USA. To date, no non-target effects have been observed either on eggplant or native species of Solanum. (author) [es

  15. PCR-TTGE analysis of 16S rRNA from rainbow trout (Oncorhynchus mykiss gut microbiota reveals host-specific communities of active bacteria.

    Directory of Open Access Journals (Sweden)

    Paola Navarrete

    Full Text Available This study assessed the relative contributions of host genetics and diet in shaping the gut microbiota of rainbow trout. Full sibling fish from four unrelated families, each consisting of individuals derived from the mating of one male and one female belonging to a breeding program, were fed diets containing either vegetable proteins or vegetable oils for two months in comparison to a control diet consisting of only fish protein and fish oil. Two parallel approaches were applied on the same samples: transcriptionally active bacterial populations were examined based on RNA analysis and were compared with bacterial populations obtained from DNA analysis. Comparison of temporal temperature gradient gel electrophoresis (TTGE profiles from DNA and RNA showed important differences, indicating that active bacterial populations were better described by RNA analysis. Results showed that some bacterial groups were significantly (P<0.05 associated with specific families, indicating that microbiota composition may be influenced by the host. In addition, the effect of diet on microbiota composition was dependent on the trout family.

  16. A tail of two phages: Genomic and functional analysis of Listeria monocytogenes phages vB_LmoS_188 and vB_LmoS_293 reveal the receptor-binding proteins involved in host specificity.

    Directory of Open Access Journals (Sweden)

    Aidan eCasey

    2015-10-01

    Full Text Available The physical characteristics of bacteriophages establish them as viable candidates for downstream development of pathogen detection assays and biocontrol measures. To utilize phages for such purposes, a detailed knowledge of their host interaction mechanisms is a prerequisite. There is currently a wealth of knowledge available concerning Gram-negative phage-host interaction, but little by comparison for Gram-positive phages and Listeria phages in particular. In this research, the lytic spectrum of two recently isolated Listeria monocytogenes phages (vB_LmoS_188 and vB_LmoS_293 was determined, and the genomic basis for their observed serotype 4b/4e host-specificity was investigated using comparative genomics. The late tail genes of these phages were identified to be highly conserved when compared to other serovar 4-specific Listeria phages. Spontaneous mutants of each of these phages with broadened host specificities were generated. Their late tail gene sequences were compared with their wild-type counterparts resulting in the putative identification of the products of ORF 19 of vB_LmoS_188 and ORF 20 of vB_LmoS_293 as the receptor binding proteins of these phages. The research findings also indicate that conserved baseplate architectures and host interaction mechanisms exist for Listeria siphoviruses with differing host-specificities, and further contribute to the current knowledge of phage-host interactions with regard to Listeria phages.

  17. Resistance to Plasmopara viticola in a grapevine segregating population is associated with stilbenoid accumulation and with specific host transcriptional responses

    Directory of Open Access Journals (Sweden)

    Delledonne Massimo

    2011-08-01

    Full Text Available Abstract Background Downy mildew, caused by the oomycete Plasmopara viticola, is a serious disease in Vitis vinifera, the most commonly cultivated grapevine species. Several wild Vitis species have instead been found to be resistant to this pathogen and have been used as a source to introgress resistance into a V. vinifera background. Stilbenoids represent the major phytoalexins in grapevine, and their toxicity is closely related to the specific compound. The aim of this study was to assess the resistance response to P. viticola of the Merzling × Teroldego cross by profiling the stilbenoid content of the leaves of an entire population and the transcriptome of resistant and susceptible individuals following infection. Results A three-year analysis of the population's response to artificial inoculation showed that individuals were distributed in nine classes ranging from total resistance to total susceptibility. In addition, quantitative metabolite profiling of stilbenoids in the population, carried out using HPLC-DAD-MS, identified three distinct groups differing according to the concentrations present and the complexity of their profiles. The high producers were characterized by the presence of trans-resveratrol, trans-piceid, trans-pterostilbene and up to thirteen different viniferins, nine of them new in grapevine. Accumulation of these compounds is consistent with a resistant phenotype and suggests that they may contribute to the resistance response. A preliminary transcriptional study using cDNA-AFLP selected a set of genes modulated by the oomycete in a resistant genotype. The expression of this set of genes in resistant and susceptible genotypes of the progeny population was then assessed by comparative microarray analysis. A group of 57 genes was found to be exclusively modulated in the resistant genotype suggesting that they are involved in the grapevine-P. viticola incompatible interaction. Functional annotation of these transcripts

  18. The role of the host-specific grasshopper Cornops aquaticum (Orthoptera: Acrididae as consumer of native Eichhornia crassipes (Pontederiaceae floating meadows

    Directory of Open Access Journals (Sweden)

    María Celeste Franceschini

    2011-09-01

    Full Text Available Cornops aquaticum is a widely distributed semiaquatic grasshopper in the Neotropics. The development, feeding and oviposition of C. aquaticum take place on Pontederiaceae, especially on species of Eichhornia. Several aspects of the feeding of C. aquaticum are studied because is one of the most important herbivores of the highly invasive floating Eichhornia crassipes in native areas. The aims of this paper were: (1 to quantify the amount of E. crassipes consumed by C. aquaticum, (2 to determine the growth rate and the conversion efficiency of food ingested by this grasshopper, and (3 to determine the possible effect of consumption on E. crassipes productivity. Thirty individuals from each specific age class were used in the experiment: nymphs A, nymphs B, adult males and adult females. Insects were individually confined in plastic pots with a leaf of E. crassipes. We estimated feeding by individual, consumption index (CI, relative growth rate (GR and efficiency of conversion of ingested food to body substance (ECI. The impact of C. aquaticum consumption on E. crassipes floating meadows was assessed with the abundance of the grasshopper, and the available data on primary production of the host plant at the study site. Food intake of C. aquaticum was 11.23% of plant productivity. Food consumption, growth rate and food conversion efficiency of this grasshopper varied according to the specific age classes. Damage caused by C. aquaticum is high in comparison with the damage caused by other semiaquatic and grassland grasshoppers, however it is not enough to prevent the growth and coverage of native E. crassipes floating meadows because abundance of grasshoppers are realtively low and the growth rate and productivity of the host plant is high. Rev. Biol. Trop. 59 (3: 1407-1418. Epub 2011 September 01.

  19. The role of the host-specific grasshopper Cornops aquaticum (Orthoptera: Acrididae) as consumer of native Eichhornia crassipes (Pontederiaceae) floating meadows.

    Science.gov (United States)

    Franceschini, María Celeste; De Wysiecki, María Laura; Poi de Neiff, Alicia; Galassi, María Eugenia; Martínez Fedra, Solange

    2011-09-01

    Cornops aquaticum is a widely distributed semiaquatic grasshopper in the Neotropics. The development, feeding and oviposition of C. aquaticum take place on Pontederiaceae, especially on species of Eichhornia. Several aspects of the feeding of C. aquaticum are studied because is one of the most important herbivores of the highly invasive floating Eichhornia crassipes in native areas. The aims of this paper were: (1) to quantify the amount of E. crassipes consumed by C. aquaticum, (2) to determine the growth rate and the conversion efficiency of food ingested by this grasshopper, and (3) to determine the possible effect of consumption on E. crassipes productivity. Thirty individuals from each specific age class were used in the experiment: nymphs A, nymphs B, adult males and adult females. Insects were individually confined in plastic pots with a leaf of E. crassipes. We estimated feeding by individual, consumption index (CI), relative growth rate (GR) and efficiency of conversion of ingested food to body substance (ECI). The impact of C. aquaticum consumption on E. crassipes floating meadows was assessed with the abundance of the grasshopper, and the available data on primary production of the host plant at the study site. Food intake of C. aquaticum was 11.23% of plant productivity. Food consumption, growth rate and food conversion efficiency of this grasshopper varied according to the specific age classes. Damage caused by C. aquaticum is high in comparison with the damage caused by other semiaquatic and grassland grasshoppers, however it is not enough to prevent the growth and coverage of native E. crassipes floating meadows because abundance of grasshoppers are realtively low and the growth rate and productivity of the host plant is high.

  20. The host response to the probiotic Escherichia coli strain Nissle 1917: Specific up-regulation of the proinflammatory chemokine MCP-1

    Directory of Open Access Journals (Sweden)

    Ukena Sya N

    2005-12-01

    Full Text Available Abstract Background The use of live microorganisms to influence positively the course of intestinal disorders such as infectious diarrhea or chronic inflammatory conditions has recently gained increasing interest as a therapeutic alternative. In vitro and in vivo investigations have demonstrated that probiotic-host eukaryotic cell interactions evoke a large number of responses potentially responsible for the effects of probiotics. The aim of this study was to improve our understanding of the E. coli Nissle 1917-host interaction by analyzing the gene expression pattern initiated by this probiotic in human intestinal epithelial cells. Methods Gene expression profiles of Caco-2 cells treated with E. coli Nissle 1917 were analyzed with microarrays. A second human intestinal cell line and also pieces of small intestine from BALB/c mice were used to confirm regulatory data of selected genes by real-time RT-PCR and cytometric bead array (CBA to detect secretion of corresponding proteins. Results Whole genome expression analysis revealed 126 genes specifically regulated after treatment of confluent Caco-2 cells with E. coli Nissle 1917. Among others, expression of genes encoding the proinflammatory molecules monocyte chemoattractant protein-1 ligand 2 (MCP-1, macrophage inflammatory protein-2 alpha (MIP-2α and macrophage inflammatory protein-2 beta (MIP-2β was increased up to 10 fold. Caco-2 cells cocultured with E. coli Nissle 1917 also secreted high amounts of MCP-1 protein. Elevated levels of MCP-1 and MIP-2α mRNA could be confirmed with Lovo cells. MCP-1 gene expression was also up-regulated in mouse intestinal tissue. Conclusion Thus, probiotic E. coli Nissle 1917 specifically upregulates expression of proinflammatory genes and proteins in human and mouse intestinal epithelial cells.

  1. 7 CFR 28.414 - Strict Low Middling Light Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... CONTAINER REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Light Spotted Cotton § 28.414 Strict Low Middling Light Spotted Color. Strict Low Middling Light Spotted Color is color which in spot or...

  2. On N. Chomsky’s strict subcategorization of verbs

    Directory of Open Access Journals (Sweden)

    Janez Orešnik

    1966-12-01

    Full Text Available This paper studies the so-called strict subcategorization rules, and the theory associated with them, in the transformational grammar of. Erigl·ish as proposed by Noarn Chomsky in his Aspects. The syntactic component of English transformational grammar consists of two mutually ordered parts, viz., the base and the transformational subcomponents. The initial part of the base are the so-called categorial rules, which are of almost exclusive interest to us here. Their primary task is to generate what are usually called basic sentence patterns, and will here, with Chomsky (Aspects, p.ll3, be designated with the expression, frames of category symbols.- The rules of the transformational subcomponent modify, in various ways, the frames generated by the base. For several reasons - one of them being that the correct work of the transformational subcomponent quite often depends on the kind of lexical items with which the syntactic positions in the frames of category symbols have been filled, the lexical items must be introduced from the lexicon into the empty positions in the frames before the rules of the transformational subcomponent can be allowed to modify the frames.

  3. Managing Hanford Site solid waste through strict acceptance criteria

    International Nuclear Information System (INIS)

    Jasen, W.G.; Pierce, R.D.; Willis, N.P.

    1993-02-01

    Various types of waste have been generated during the 50-year history of the Hanford Site. Regulatory changes in the last 20 years have provided the emphasis for better management of these wastes. Interpretations of the Atomic Energy Act of 1954 (AEA) and the Resource Conservation and Recovery Act of 1976 (RCRA) have led to the definition of a group of wastes called radioactive mixed wastes (RMW). As a result of the radioactive and hazardous properties of these wastes, strict management programs have been implemented for the management of these wastes. Solid waste management is accomplished through a systems performance approach to waste management that used best-demonstrated available technology (BDAT) and best management practices. The solid waste program at the Hanford Site strives to integrate all aspects of management relative to the treatment, storage and disposal (TSD) of solid waste. Often there are many competing and important needs. It is a difficult task to balance these needs in a manner that is both equitable and productive. Management science is used to help the process of making decisions. Tools used to support the decision making process include five-year planning, cost estimating, resource allocation, performance assessment, waste volume forecasts, input/output models, and waste acceptance criteria. The purpose of this document is to describe how one of these tools, waste acceptance criteria, has helped the Hanford Site manage solid wastes

  4. Effects of strict prolonged bed rest on cardiorespiratory fitness

    DEFF Research Database (Denmark)

    Ried-Larsen, Mathias; Aarts, Hugo M; Joyner, Michael J

    2017-01-01

    with larger declines in V̇o2max). Furthermore, the systematic review revealed a gap in the knowledge about the cardiovascular response to extreme physical inactivity, particularly in older subjects and women of any age group. In addition to its relevance to spaceflight, this lack of data has significant....... Since 1949, 80 studies with a total of 949 participants (>90% men) have been published with data on strict bed rest and V̇o2max The studies were conducted mainly in young participants [median age (interquartile range) 24.5 (22.4-34.0) yr]. The duration of bed rest ranged from 1 to 90 days. V̇o2max...... declined linearly across bed rest duration. No statistical difference in the decline among studies reporting V̇o2max as l/min (-0.3% per day) compared with studies reporting V̇o2max normalized to body weight (ml·kg-1·min-1; -0.43% per day) was observed. Although both total body weight and lean body mass...

  5. Fixed point iterations for strictly hemi-contractive maps in uniformly smooth Banach spaces

    International Nuclear Information System (INIS)

    Chidume, C.E.; Osilike, M.O.

    1993-05-01

    It is proved that the Mann iteration process converges strongly to the fixed point of a strictly hemi-contractive map in real uniformly smooth Banach spaces. The class of strictly hemi-contractive maps includes all strictly pseudo-contractive maps with nonempty fixed point sets. A related result deals with the Ishikawa iteration scheme when the mapping is Lipschitzian and strictly hemi-contractive. Our theorems generalize important known results. (author). 29 refs

  6. Effect of cryopreservation and lyophilization on viability and growth of strict anaerobic human gut microbes.

    Science.gov (United States)

    Bircher, Lea; Geirnaert, Annelies; Hammes, Frederik; Lacroix, Christophe; Schwab, Clarissa

    2018-04-17

    Strict anaerobic gut microbes have been suggested as 'next-generation probiotics' for treating several intestinal disorders. The development of preservation techniques is of major importance for therapeutic application. This study investigated cryopreservation (-80°C) and lyophilization survival and storage stability (4°C for 3 months) of the strict anaerobic gut microbes Bacteroides thetaiotaomicron, Faecalibacterium prausnitzii, Roseburia intestinalis, Anaerostipes caccae, Eubacterium hallii and Blautia obeum. To improve preservation survival, protectants sucrose and inulin (both 5% w/v) were added for lyophilization and were also combined with glycerol (15% v/v) for cryopreservation. Bacterial fitness, evaluated by maximum growth rate and lag phase, viability and membrane integrity were determined using a standardized growth assay and by flow cytometry as markers for preservation resistance. Lyophilization was more detrimental to viability and fitness than cryopreservation, but led to better storage stability. Adding sucrose and inulin enhanced viability and the proportion of intact cells during lyophilization of all strains. Viability of protectant-free B. thetaiotaomicron, A. caccae and F. prausnitzii was above 50% after cryopreservation and storage and increased to above 80% if protectants were present. The addition of glycerol, sucrose and inulin strongly enhanced the viability of B. obeum, E. hallii and R. intestinalis from 0.03-2% in protectant-free cultures to 11-37%. This is the first study that quantitatively compared the effect of cryopreservation and lyophilization and the addition of selected protectants on viability and fitness of six strict anaerobic gut microbes. Our results suggest that efficiency of protectants is process- and species-specific. © 2018 The Authors. Microbial Biotechnology published by John Wiley & Sons Ltd and Society for Applied Microbiology.

  7. Host specificity in Fusarium oxysporum

    NARCIS (Netherlands)

    van Dam, P.

    2017-01-01

    Fusarium oxysporum is a fungal pathogen that can cause severe wilt disease and root rot in various plant species. Every individual strain is restricted to causing disease in only one or a few plant species. In this thesis, we focused on identifying novel virulence factors (‘effectors’) secreted by

  8. Genomic Diversification of Enterococci in Hosts: the role of the mobilome

    Directory of Open Access Journals (Sweden)

    Maria eSantagati

    2012-03-01

    Full Text Available Enterococci are ubiquitous lactic acid bacteria, possessing a flexible nature that allows them to colonize various environments and hosts but also to be opportunistic pathogens. Many papers have contributed to a better understanding of: i the taxonomy of this complex group of microorganisms; ii intra-species variability; iii the role of different pathogenicity traits; and iv some markers related to the character of host-specificity, but the reasons of such incredible success of adaptability is still far from being fully explained.Recently, genomic-based studies have improved our understanding of the genome diversity of the most studied species i.e. E. faecalis and E. faecium. From these studies, what is becoming evident is the role of the mobilome in adding new abilities to colonize new hosts and environments, and eventually in driving their evolution: specific clones associated with human infections or specific hosts can exist, but probably the consideration of these populations as strictly clonal groups is only partially correct. The variable presence of mobile-genetic elements may, indeed, be one of the factors involved in the evolution of one specific group in a specific host and/or environment. Certainly more extensive studies using new high throughput technologies are mandatory to fully understand the evolution of predominant clones and species in different hosts and environments.

  9. Identification, Validation and Utilization of Novel Nematode-Responsive Root-Specific Promoters in Arabidopsis for Inducing Host-Delivered RNAi Mediated Root-Knot Nematode Resistance

    Directory of Open Access Journals (Sweden)

    Atul Kakrana

    2017-12-01

    Full Text Available The root-knot nematode (RKN, Meloidogyne incognita, is an obligate, sedentary endoparasite that infects a large number of crops and severely affects productivity. The commonly used nematode control strategies have their own limitations. Of late, RNA interference (RNAi has become a popular approach for the development of nematode resistance in plants. Transgenic crops capable of expressing dsRNAs, specifically in roots for disrupting the parasitic process, offer an effective and efficient means of producing resistant crops. We identified nematode-responsive and root-specific (NRRS promoters by using microarray data from the public domain and known conserved cis-elements. A set of 51 NRRS genes was identified which was narrowed down further on the basis of presence of cis-elements combined with minimal expression in the absence of nematode infection. The comparative analysis of promoters from the enriched NRRS set, along with earlier reported nematode-responsive genes, led to the identification of specific cis-elements. The promoters of two candidate genes were used to generate transgenic plants harboring promoter GUS constructs and tested in planta against nematodes. Both promoters showed preferential expression upon nematode infection, exclusively in the root in one and galls in the other. One of these NRRS promoters was used to drive the expression of splicing factor, a nematode-specific gene, for generating host-delivered RNAi-mediated nematode-resistant plants. Transgenic lines expressing dsRNA of splicing factor under the NRRS promoter exhibited upto a 32% reduction in number of galls compared to control plants.

  10. Influenza A Virus Infection Predisposes Hosts to Secondary Infection with Different Streptococcus pneumoniae Serotypes with Similar Outcome but Serotype-Specific Manifestation

    Science.gov (United States)

    Sharma-Chawla, Niharika; Sender, Vicky; Kershaw, Olivia; Gruber, Achim D.; Volckmar, Julia; Henriques-Normark, Birgitta

    2016-01-01

    Influenza A virus (IAV) and Streptococcus pneumoniae are major causes of respiratory tract infections, particularly during coinfection. The synergism between these two pathogens is characterized by a complex network of dysregulated immune responses, some of which last until recovery following IAV infection. Despite the high serotype diversity of S. pneumoniae and the serotype replacement observed since the introduction of conjugate vaccines, little is known about pneumococcal strain dependency in the enhanced susceptibility to severe secondary S. pneumoniae infection following IAV infection. Thus, we studied how preinfection with IAV alters host susceptibility to different S. pneumoniae strains with various degrees of invasiveness using a highly invasive serotype 4 strain, an invasive serotype 7F strain, and a carrier serotype 19F strain. A murine model of pneumococcal coinfection during the acute phase of IAV infection showed a significantly increased degree of pneumonia and mortality for all tested pneumococcal strains at otherwise sublethal doses. The incidence and kinetics of systemic dissemination, however, remained bacterial strain dependent. Furthermore, we observed strain-specific alterations in the pulmonary levels of alveolar macrophages, neutrophils, and inflammatory mediators ultimately affecting immunopathology. During the recovery phase following IAV infection, bacterial growth in the lungs and systemic dissemination were enhanced in a strain-dependent manner. Altogether, this study shows that acute IAV infection predisposes the host to lethal S. pneumoniae infection irrespective of the pneumococcal serotype, while the long-lasting synergism between IAV and S. pneumoniae is bacterial strain dependent. These results hold implications for developing tailored therapeutic treatment regimens for dual infections during future IAV outbreaks. PMID:27647871

  11. Meso- and bathy-pelagic fish parasites at the Mid-Atlantic Ridge (MAR): Low host specificity and restricted parasite diversity

    Science.gov (United States)

    Klimpel, Sven; Busch, Markus Wilhelm; Sutton, Tracey; Palm, Harry Wilhelm

    2010-04-01

    Seven meso- and bathy-pelagic fish species from the Mid-Atlantic Ridge (MAR) were firstly studied for fish parasites and feeding ecology. With a total of seven parasite species, the 247 meso- and bathy-pelagic deep-sea fish specimens belonging to the families Melamphaidae (3 spp.), Myctophidae (3 spp.) and Stomiidae (1 sp.) revealed low parasite diversity. The genetically identified nematodes Anisakis simplex (s.s.) and Anisakis pegreffii from the body cavity, liver and muscles of Myctophum punctatum were the most abundant parasites, reaching a prevalence of 91.4% and mean intensity of 3.1 (1-14). Anisakis sp. (unidentified) infected Chauliodus sloani and Poromitra crassiceps. Bothriocephalidean and tetraphyllidean cestode larvae infected Benthosema glaciale, the latter also occurring in C. sloani and Scopelogadus beanii, at low prevalences. Adult parasites at low infection rates included the digenean Lethadena sp. (2.9%), and the two copepod species Sarcotretes scopeli (5.7%) and Tautochondria dolichoura (5.3-11.4%). The myctophid Lampanyctus macdonaldi and the melamphaid Scopelogadus mizolepis mizolepis were free of parasites. Analyses of the stomach contents revealed crustaceans, especially copepods and euphausiids for the myctophids and also amphipods for the melamphaids as predominant prey items. While all stomachs showing distinct content comprising often unidentified 'tissue' (possibly gelatinous zooplankton), only C. sloani preyed upon fish. Though this feeding habit would enable transfer of a variety of crustacean-transmitted parasites into the fish, the parasite fauna in the meso- and bathy-pelagic fish was species poor. All observed parasites showed low host specificity, demonstrating no distinct pattern of host-parasite co-evolution. The MAR is no barrier for the parasite distribution in the North Atlantic meso- and bathy-pelagial.

  12. Stage-specific excretory-secretory small heat shock proteins from the parasitic nematode Strongyloides ratti--putative links to host's intestinal mucosal defense system.

    Science.gov (United States)

    Younis, Abuelhassan Elshazly; Geisinger, Frank; Ajonina-Ekoti, Irene; Soblik, Hanns; Steen, Hanno; Mitreva, Makedonka; Erttmann, Klaus D; Perbandt, Markus; Liebau, Eva; Brattig, Norbert W

    2011-09-01

    In a search for molecules involved in the interaction between intestinal nematodes and mammalian mucosal host cells, we performed MS to identify excretory-secretory proteins from Strongyloides ratti. In the excretory-secretory proteins of the parasitic female stage, we detected, in addition to other peptides, peptides homologous with the Caenorhabditis elegans heat shock protein (HSP)-17, named Sra-HSP-17.1 (∼ 19 kDa) and Sra-HSP-17.2 (∼ 18 kDa), with 49% amino acid identity. The full-length cDNAs (483 bp and 474 bp, respectively) were identified, and the genomic organization was analyzed. To allow further characterization, the proteins were recombinantly expressed and purified. Profiling of transcription by quantitative real-time-PCR and of protein by ELISA in various developmental stages revealed parasitic female-specific expression. Sequence analyses of both the DNA and amino acid sequences showed that the two proteins share a conserved α-crystallin domain and variable N-terminals. The Sra-HSP-17s showed the highest homology with the deduced small HSP sequence of the human pathogen Strongyloides stercoralis. We observed strong immunogenicity of both proteins, leading to strong IgG responses following infection of rats. Flow cytometric analysis indicated the binding of Sra-HSP-17s to the monocyte-macrophage lineage but not to peripheral lymphocytes or neutrophils. A rat intestinal epithelial cell line showed dose-dependent binding to Sra-HSP-17.1, but not to Sra-HSP-17.2. Exposed monocytes released interleukin-10 but not tumor necrosis factor-α in response to Sra-HSP-17s, suggesting the possible involvement of secreted female proteins in host immune responses. © 2011 The Authors Journal compilation © 2011 FEBS.

  13. Multiple markers pyrosequencing reveals highly diverse and host-specific fungal communities on the mangrove trees Avicennia marina and Rhizophora stylosa.

    Science.gov (United States)

    Arfi, Yonathan; Buée, Marc; Marchand, Cyril; Levasseur, Anthony; Record, Eric

    2012-02-01

    Fungi are important actors in ecological processes and trophic webs in mangroves. Although saprophytic fungi occurring in the intertidal part of mangrove have been well studied, little is known about the diversity and structure of the fungal communities in this ecosystem or about the importance of functional groups like pathogens and mutualists. Using tag-encoded 454 pyrosequencing of the ITS1, ITS2, nu-ssu-V5 and nu-ssu-V7 regions, we studied and compared the fungal communities found on the marine and aerial parts of Avicennia marina and Rhizophora stylosa trees in a mangrove in New Caledonia. A total of 209,544 reads were analysed, corresponding to several thousand molecular operational taxonomic units (OTU). There is a marked zonation in the species distribution, with most of the OTU being found specifically in one of the microhabitat studied. Ascomycetes are the dominant phylum (82%), Basidiomycetes are very rare (3%), and 15% of the sequences correspond to unknown taxa. Our results indicate that host specificity is a key factor in the distribution of the highly diverse fungal communities, in both the aerial and intertidal parts of the trees. This study also validates the usefulness of multiple markers in tag-encoded pyrosequencing to consolidate and refine the assessment of the taxonomic diversity. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  14. General aspects concerning strictly meat and fish transmitted parasitic infections

    Directory of Open Access Journals (Sweden)

    Daniele Crotti

    2012-03-01

    Full Text Available All helminths parasitosis transmitted to humans trough ingestion of infested fleshes, where man is definitive host too, are represented by four groups of helminths: the cestodes Dyphyllobothrium spp and Spirometra spp. (Sparganum proliferum is the name of the immature plerocercoid larva, the trematodes Opisthorchis Clonorchis “group” (many could be the genera and species involved, and the nematode Capillaria philippinensis. So, for fishes humans foods (fresh or salted water the control and prevention in veterinary health must be directed to investigation regarding intermediate stages of these parasites in fishes for human alimentation; if present, they must be eliminated. The helminths parasitosis transmitted to humans trough ingestion of infected mammals meats, are represented by taeniasis (Taenia saginata, T. solium and T. saginata asiatica, where man id definitive host and the infection is caused by ingestion of bovine or swine meat, containing larvae of these cestodes, and by trichinellosis, where humans represent a intermediate stage, and the eventual pathology is caused as by adult (acute infection as by larvae (chronic infection of this nematode: usually the meats responsible are infected pork, wild pork or horse (Trichinella spp. Is inside the meats of these animals. So the veterinary control and prophylaxis are necessary to avoid this disease and preventing the infection that could be severe.

  15. Host niches and defensive extended phenotypes structure parasitoid wasp communities.

    Directory of Open Access Journals (Sweden)

    Richard Bailey

    2009-08-01

    Full Text Available Oak galls are spectacular extended phenotypes of gallwasp genes in host oak tissues and have evolved complex morphologies that serve, in part, to exclude parasitoid natural enemies.Parasitoids and their insect herbivore hosts have coevolved to produce diverse communities comprising about a third of all animal species. The factors structuring these communities, however, remain poorly understood. An emerging theme in community ecology is the need to consider the effects of host traits, shaped by both natural selection and phylogenetic history, on associated communities of natural enemies. Here we examine the impact of host traits and phylogenetic relatedness on 48 ecologically closed and species-rich communities of parasitoids attacking gall-inducing wasps on oaks. Gallwasps induce the development of spectacular and structurally complex galls whose species- and generation-specific morphologies are the extended phenotypes of gallwasp genes. All the associated natural enemies attack their concealed hosts through gall tissues, and several structural gall traits have been shown to enhance defence against parasitoid attack. Here we explore the significance of these and other host traits in predicting variation in parasitoid community structure across gallwasp species. In particular, we test the "Enemy Hypothesis," which predicts that galls with similar morphology will exclude similar sets of parasitoids and therefore have similar parasitoid communities. Having controlled for phylogenetic patterning in host traits and communities, we found significant correlations between parasitoid community structure and several gall structural traits (toughness, hairiness, stickiness, supporting the Enemy Hypothesis. Parasitoid community structure was also consistently predicted by components of the hosts' spatiotemporal niche, particularly host oak taxonomy and gall location (e.g., leaf versus bud versus seed. The combined explanatory power of structural and

  16. Host Niches and Defensive Extended Phenotypes Structure Parasitoid Wasp Communities

    Science.gov (United States)

    Bailey, Richard; Schönrogge, Karsten; Cook, James M.; Melika, George; Csóka, György; Thuróczy, Csaba; Stone, Graham N.

    2009-01-01

    Oak galls are spectacular extended phenotypes of gallwasp genes in host oak tissues and have evolved complex morphologies that serve, in part, to exclude parasitoid natural enemies. Parasitoids and their insect herbivore hosts have coevolved to produce diverse communities comprising about a third of all animal species. The factors structuring these communities, however, remain poorly understood. An emerging theme in community ecology is the need to consider the effects of host traits, shaped by both natural selection and phylogenetic history, on associated communities of natural enemies. Here we examine the impact of host traits and phylogenetic relatedness on 48 ecologically closed and species-rich communities of parasitoids attacking gall-inducing wasps on oaks. Gallwasps induce the development of spectacular and structurally complex galls whose species- and generation-specific morphologies are the extended phenotypes of gallwasp genes. All the associated natural enemies attack their concealed hosts through gall tissues, and several structural gall traits have been shown to enhance defence against parasitoid attack. Here we explore the significance of these and other host traits in predicting variation in parasitoid community structure across gallwasp species. In particular, we test the “Enemy Hypothesis,” which predicts that galls with similar morphology will exclude similar sets of parasitoids and therefore have similar parasitoid communities. Having controlled for phylogenetic patterning in host traits and communities, we found significant correlations between parasitoid community structure and several gall structural traits (toughness, hairiness, stickiness), supporting the Enemy Hypothesis. Parasitoid community structure was also consistently predicted by components of the hosts' spatiotemporal niche, particularly host oak taxonomy and gall location (e.g., leaf versus bud versus seed). The combined explanatory power of structural and spatiotemporal

  17. NleB/SseK effectors from Citrobacter rodentium, Escherichia coli, and Salmonella enterica display distinct differences in host substrate specificity

    DEFF Research Database (Denmark)

    El Qaidi, Samir; Chen, Kangming; Halim, Adnan

    2017-01-01

    factor (TNF) Receptor-Associated Factor 2 (TRAF2) ubiquitination. These results provide evidence that members of this highly conserved family of bacterial virulence effectors target different host protein substrates and exhibit distinct cellular modes of action to suppress host responses.......Many Gram-negative bacterial pathogens use a syringe-like apparatus called a type III secretion system to inject virulence factors into host cells. Some of these effectors are enzymes that modify host proteins to subvert their normal functions. NleB is a glycosyltransferase that modifies host...... proteins with N-acetyl-D-glucosamine to inhibit antibacterial and inflammatory host responses. NleB is conserved among the attaching/effacing pathogens enterohemorrhagic E. coli (EHEC), enteropathogenic E. coli (EPEC), and Citrobacter rodentium. Moreover, Salmonella enterica strains encode up to three Nle...

  18. Multi-faceted proteomic characterization of host protein complement of Rift Valley fever virus virions and identification of specific heat shock proteins, including HSP90, as important viral host factors.

    Science.gov (United States)

    Nuss, Jonathan E; Kehn-Hall, Kylene; Benedict, Ashwini; Costantino, Julie; Ward, Michael; Peyser, Brian D; Retterer, Cary J; Tressler, Lyal E; Wanner, Laura M; McGovern, Hugh F; Zaidi, Anum; Anthony, Scott M; Kota, Krishna P; Bavari, Sina; Hakami, Ramin M

    2014-01-01

    Rift Valley fever is a potentially fatal disease of humans and domestic animals caused by Rift Valley fever virus (RVFV). Infection with RVFV in ruminants can cause near 100% abortion rates and recent outbreaks in naïve human populations have suggested case fatality rates of greater than thirty percent. To elucidate the roles that host proteins play during RVFV infection, proteomic analysis of RVFV virions was conducted using complementary analytical approaches, followed by functional validation studies of select identified host factors. Coupling the more traditional Gel LC/MS/MS approach (SDS PAGE followed by liquid chromatography tandem mass spectrometry) with an alternative technique that preserves protein complexes allowed the protein complement of these viral particles to be thoroughly examined. In addition to viral proteins present within the virions and virion-associated host proteins, multiple macromolecular complexes were identified. Bioinformatic analysis showed that host chaperones were among over-represented protein families associated with virions, and functional experiments using siRNA gene silencing and small molecule inhibitors identified several of these heat shock proteins, including heat shock protein 90 (HSP90), as important viral host factors. Further analysis indicated that HSP inhibition effects occur during the replication/transcription phase of the virus life cycle, leading to significant lowering of viral titers without compromising the functional capacity of released virions. Overall, these studies provide much needed further insight into interactions between RVFV and host cells, increasing our understanding of the infection process and suggesting novel strategies for anti-viral development. In particular, considering that several HSP90 inhibitors have been advancing through clinical trials for cancer treatment, these results also highlight the exciting potential of repurposing HSP90 inhibitors to treat RVF.

  19. Multi-faceted proteomic characterization of host protein complement of Rift Valley fever virus virions and identification of specific heat shock proteins, including HSP90, as important viral host factors.

    Directory of Open Access Journals (Sweden)

    Jonathan E Nuss

    Full Text Available Rift Valley fever is a potentially fatal disease of humans and domestic animals caused by Rift Valley fever virus (RVFV. Infection with RVFV in ruminants can cause near 100% abortion rates and recent outbreaks in naïve human populations have suggested case fatality rates of greater than thirty percent. To elucidate the roles that host proteins play during RVFV infection, proteomic analysis of RVFV virions was conducted using complementary analytical approaches, followed by functional validation studies of select identified host factors. Coupling the more traditional Gel LC/MS/MS approach (SDS PAGE followed by liquid chromatography tandem mass spectrometry with an alternative technique that preserves protein complexes allowed the protein complement of these viral particles to be thoroughly examined. In addition to viral proteins present within the virions and virion-associated host proteins, multiple macromolecular complexes were identified. Bioinformatic analysis showed that host chaperones were among over-represented protein families associated with virions, and functional experiments using siRNA gene silencing and small molecule inhibitors identified several of these heat shock proteins, including heat shock protein 90 (HSP90, as important viral host factors. Further analysis indicated that HSP inhibition effects occur during the replication/transcription phase of the virus life cycle, leading to significant lowering of viral titers without compromising the functional capacity of released virions. Overall, these studies provide much needed further insight into interactions between RVFV and host cells, increasing our understanding of the infection process and suggesting novel strategies for anti-viral development. In particular, considering that several HSP90 inhibitors have been advancing through clinical trials for cancer treatment, these results also highlight the exciting potential of repurposing HSP90 inhibitors to treat RVF.

  20. Brucella melitensis global gene expression study provides novel information on growth phase-specific gene regulation with potential insights for understanding Brucella:host initial interactions

    Directory of Open Access Journals (Sweden)

    Garner Harold R

    2009-05-01

    Full Text Available Abstract Background Brucella spp. are the etiological agents of brucellosis, a zoonotic infectious disease that causes abortion in animals and chronic debilitating illness in humans. Natural Brucella infections occur primarily through an incompletely defined mechanism of adhesion to and penetration of mucosal epithelium. In this study, we characterized changes in genome-wide transcript abundance of the most and the least invasive growth phases of B. melitensis cultures to HeLa cells, as a preliminary approach for identifying candidate pathogen genes involved in invasion of epithelial cells. Results B. melitensis at the late logarithmic phase of growth are more invasive to HeLa cells than mid-logarithmic or stationary growth phases. Microarray analysis of B. melitensis gene expression identified 414 up- and 40 down-regulated genes in late-log growth phase (the most invasive culture compared to the stationary growth phase (the least invasive culture. As expected, the majority of up-regulated genes in late-log phase cultures were those associated with growth, including DNA replication, transcription, translation, intermediate metabolism, energy production and conversion, membrane transport, and biogenesis of the cell envelope and outer membrane; while the down-regulated genes were distributed among several functional categories. Conclusion This Brucella global expression profile study provides novel information on growth phase-specific gene expression. Further characterization of some genes found differentially expressed in the most invasive culture will likely bring new insights into the initial molecular interactions between Brucella and its host.

  1. Role of net charge on catalytic domain and influence of cell wall binding domain on bactericidal activity, specificity, and host range of phage lysins.

    Science.gov (United States)

    Low, Lieh Yoon; Yang, Chen; Perego, Marta; Osterman, Andrei; Liddington, Robert

    2011-09-30

    The recombinant lysins of lytic phages, when applied externally to Gram-positive bacteria, can be efficient bactericidal agents, typically retaining high specificity. Their development as novel antibacterial agents offers many potential advantages over conventional antibiotics. Protein engineering could exploit this potential further by generating novel lysins fit for distinct target populations and environments. However, access to the peptidoglycan layer is controlled by a variety of secondary cell wall polymers, chemical modifications, and (in some cases) S-layers and capsules. Classical lysins require a cell wall-binding domain (CBD) that targets the catalytic domain to the peptidoglycan layer via binding to a secondary cell wall polymer component. The cell walls of Gram-positive bacteria generally have a negative charge, and we noticed a correlation between (positive) charge on the catalytic domain and bacteriolytic activity in the absence of the CBD (nonclassical behavior). We investigated a physical basis for this correlation by comparing the structures and activities of pairs of lysins where the lytic activity of one of each pair was CBD-independent. We found that by engineering a reversal of sign of the net charge of the catalytic domain, we could either eliminate or create CBD dependence. We also provide evidence that the S-layer of Bacillus anthracis acts as a molecular sieve that is chiefly size-dependent, favoring catalytic domains over full-length lysins. Our work suggests a number of facile approaches for fine-tuning lysin activity, either to enhance or reduce specificity/host range and/or bactericidal potential, as required.

  2. The Success Rate of Initial {sup 131I} Ablation in Differentiated Thyroid Cancer: Comparison Between Less strict and Very Strict Low Iodine Diets

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Ik Dong; Kim, Sung Hoon; Seo, Ye Young; Oh, Jin Kyoung; O, Joo Hyun; Chung, Soo Kyo [The Catholic Univ. of Korea, Seoul (Korea, Republic of)

    2012-03-15

    To decrease the risk of recurrence or metastasis in differentiated thyroid cancer (DTC), selected patients receive radioactive iodine ablation of remnant thyroid tissue or tumor. A low iodine diet can enhance uptake of radioactive iodine. We compared the success rates of radioactive iodine ablation therapy in patients who followed two different low iodine diets (LIDs). The success rates of postsurgical radioactive iodine ablation in DTC patients receiving empiric doses of 150 mCi were retrospectively reviewed. First-time radioactive iodine ablation therapy was done in 71 patients following less strict LID. Less strict LID restricted seafood, iodized salt, egg yolk, dairy products, processed meat, instant prepared meals, and multivitamins. Very strict LID additionally restricted rice, freshwater fish, spinach, and soybean products. Radioactive iodine ablation therapy was considered successful when follow up {sup 123I} whole body scan was negative and stimulated serum thyroglobulin level was less than 2.0 ng/mL. The success rate of patients following less strict LID was 80.3% and for very strict LID 75.6%. There was no statistically significant difference in the success rates between the two LID groups (P=0.48). Very strict LID may not contribute to improving the success rate of initial radioactive iodine ablation therapy at the cost of great inconvenience to the patient.

  3. Assessing birth asphyxia using strictly observational signs, the ARC ...

    African Journals Online (AJOL)

    developed by Dr Sultan Omar Sultan was pre-tested at St Francis Hospital Ifakara in 2008 , then tested on 340 newborns in Temeke Hospital and Mnazi Mmoja Hospital. It was found be more sensitive, more specific and more reliable and ultimately ...

  4. Year Class Coexistence or Competitive Exclusion for Strict Biennials?

    NARCIS (Netherlands)

    Davydova, N.V.; Diekmann, O.; van Gils, Stephanus A.

    2001-01-01

    We consider a discrete time model of semelparous biennial population dynamics. Interactions between individuals are modelled with the aid of an 'environmental'' variable I. The impact on and the sensitivity to the environmental condition is age specific. The main result is that competitive exclusion

  5. Year class coexistence or competitive exclusion for strict biennials?

    NARCIS (Netherlands)

    Davydova, N.V.; Diekmann, O.; van Gils, S.A.

    2003-01-01

    We consider a discrete time model of semelparous biennial population dynamics. Interactions between individuals are modelled with the aid of an ``environmental'' variable I. The impact on and the sensitivity to the environmental condition is age specific. The main result is that competitive

  6. The role of the host-specific grasshopper Cornops aquaticum (Orthoptera: Acrididae as consumer of native Eichhornia crassipes (Pontederiaceae floating meadows

    Directory of Open Access Journals (Sweden)

    María Celeste Franceschini

    2011-09-01

    Full Text Available Cornops aquaticum is a widely distributed semiaquatic grasshopper in the Neotropics. The development, feeding and oviposition of C. aquaticum take place on Pontederiaceae, especially on species of Eichhornia. Several aspects of the feeding of C. aquaticum are studied because is one of the most important herbivores of the highly invasive floating Eichhornia crassipes in native areas. The aims of this paper were: (1 to quantify the amount of E. crassipes consumed by C. aquaticum, (2 to determine the growth rate and the conversion efficiency of food ingested by this grasshopper, and (3 to determine the possible effect of consumption on E. crassipes productivity. Thirty individuals from each specific age class were used in the experiment: nymphs A, nymphs B, adult males and adult females. Insects were individually confined in plastic pots with a leaf of E. crassipes. We estimated feeding by individual, consumption index (CI, relative growth rate (GR and efficiency of conversion of ingested food to body substance (ECI. The impact of C. aquaticum consumption on E. crassipes floating meadows was assessed with the abundance of the grasshopper, and the available data on primary production of the host plant at the study site. Food intake of C. aquaticum was 11.23% of plant productivity. Food consumption, growth rate and food conversion efficiency of this grasshopper varied according to the specific age classes. Damage caused by C. aquaticum is high in comparison with the damage caused by other semiaquatic and grassland grasshoppers, however it is not enough to prevent the growth and coverage of native E. crassipes floating meadows because abundance of grasshoppers are realtively low and the growth rate and productivity of the host plant is high. Rev. Biol. Trop. 59 (3: 1407-1418. Epub 2011 September 01.Cornops aquaticum es una tucura semiacuática Neotropical que vive asociada a las Pontederiaceae y constituye uno de los más importantes herbívoros de

  7. Endophytic bacterial communities in three arctic plants from low arctic fell tundra are cold-adapted and host-plant specific

    NARCIS (Netherlands)

    Nissinen, Riitta M.; Mannisto, Minna K.; van Elsas, Jan Dirk

    2012-01-01

    Endophytic bacteria inhabit internal plant tissues, and have been isolated from a large diversity of plants, where they form nonpathogenic relationships with their hosts. This study combines molecular and culture-dependent approaches to characterize endophytic bacterial communities of three

  8. Assessing unintended effects of a mammary-specific transgene at the whole animal level in host and non-target animals.

    Science.gov (United States)

    Clark, Merritt; Murray, James D; Maga, Elizabeth A

    2014-04-01

    Risk assessment in transgenic plants is intrinsically different than that for transgenic animals; however both require the verification of proper transgene function and in conjunction, an estimate of any unintended effects caused by expression of the transgene. This work was designed to gather data regarding methodologies to detect pleiotropic effects at the whole animal level using a line of transgenic goats that produce the antimicrobial protein human lysozyme (hLZ) in their milk with the goal of using the milk to treat childhood diarrhea. Metabolomics was used to determine the serum metabolite profile of both the host (lactating does) and non-target organism (kid goats raised on control or hLZ milk) prior to weaning (60 days), at weaning (90 days) and 1 month post-weaning (120 days). In addition, intestinal histology of the kid goats was also carried out. Histological analysis of intestinal segments of the pre-weaning group revealed significantly wider duodenal villi (p = 0.014) and significantly longer villi (p = 0.028) and deeper crypts (p = 0.030) in the ileum of kid goats consuming hLZ milk. Serum metabolomics was capable of detecting differences over time but revealed no significant differences in metabolites between control and hLZ fed kids after correction for false discovery rate. Serum metabolomics of control or hLZ lactating does showed only one significant difference in an unknown metabolite (q = 0.0422). The results as a whole indicate that consumption of hLZ milk results in positive or insignificant intestinal morphology and metabolic changes. This work contributes to the establishment of the safety and durability of the hLZ mammary-specific transgene.

  9. Insect-Specific Flaviviruses: A Systematic Review of Their Discovery, Host Range, Mode of Transmission, Superinfection Exclusion Potential and Genomic Organization

    Directory of Open Access Journals (Sweden)

    Bradley J. Blitvich

    2015-04-01

    Full Text Available There has been a dramatic increase in the number of insect-specific flaviviruses (ISFs discovered in the last decade. Historically, these viruses have generated limited interest due to their inability to infect vertebrate cells. This viewpoint has changed in recent years because some ISFs have been shown to enhance or suppress the replication of medically important flaviviruses in co-infected mosquito cells. Additionally, comparative studies between ISFs and medically important flaviviruses can provide a unique perspective as to why some flaviviruses possess the ability to infect and cause devastating disease in humans while others do not. ISFs have been isolated exclusively from mosquitoes in nature but the detection of ISF-like sequences in sandflies and chironomids indicates that they may also infect other dipterans. ISFs can be divided into two distinct phylogenetic groups. The first group currently consists of approximately 12 viruses and includes cell fusing agent virus, Kamiti River virus and Culex flavivirus. These viruses are phylogenetically distinct from all other known flaviviruses. The second group, which is apparently not monophyletic, currently consists of nine viruses and includes Chaoyang virus, Nounané virus and Lammi virus. These viruses phylogenetically affiliate with mosquito/vertebrate flaviviruses despite their apparent insect-restricted phenotype. This article provides a review of the discovery, host range, mode of transmission, superinfection exclusion ability and genomic organization of ISFs. This article also attempts to clarify the ISF nomenclature because some of these viruses have been assigned more than one name due to their simultaneous discoveries by independent research groups.

  10. Strict stoichiometric homeostasis of Cryptomonas pyrenoidifera (Cryptophyceae in relation to N:P supply ratios

    Directory of Open Access Journals (Sweden)

    Eloísa Ramos Rodríguez

    2016-11-01

    Full Text Available A common freshwater cryptophyte, Cryptomonas pyrenoidifera, was cultivated in batch-cultures to analyze intraspecific variation in elemental stoichiometry along a broad gradient of pulsed phosphorus (P enrichment during the early acclimation period and to determine the immediate homeostatic capacity of the nitrogen-to-phosphorus (N:P ratio of this alga when nutrients are at saturating levels. Experimental results revealed that nitrogen (N and P cell quotas significantly increased with increasing P concentration. However, despite the wide range of N:P ratios in the medium, Cryptomonas N:P ratios were highly stable at higher P-level treatments, indicating a highly conservative behavior and suggesting strict elemental homeostasis when nutrients are at saturating levels. The strictly homeostatic N:P ratio appears to be attributable to their high potential for a fast luxury consumption of both N and P after a brief and intense episode of increased resource availability and to physiological limits on their nutrient storage capacity. Most importantly, the N:P biomass ratio at nutrient saturating levels converged around 11:1, which was the observed ratio of maximum internal cell quotas for N and P (i.e. Qmax,N:Qmax,P under the prevailing experimental conditions. This value is particularly informative for C. pyrenoidifera because it represents cell storage quotients and may be a taxon-specific evolutionary optimum, providing a reference point to infer the grade of nutrient-limitation. The experimental data give ranges of variation in C. pyrenoidifera elemental composition permitting, among others, proper parameterization of cryptophyte stoichiometry models.

  11. The ectoparasitic wasp Eulophus pennicornis (Hymenoptera: Eulophidae) uses instar-specific endocrine disruption strategies to suppress the development of its host Lacanobia oleracea (Lepidoptera: Noctuidae).

    Science.gov (United States)

    Edwards, John P; Bell, Howard A; Audsley, Neil; Marris, Gay C; Kirkbride-Smith, Anne; Bryning, Gareth; Frisco, Caroline; Cusson, Michel

    2006-01-01

    To successfully complete its development, the gregarious ectoparasitoid Eulophus pennicornis must inhibit the moult of its host, Lacanobia oleracea. In the present study, we examined the possibility that moult- and metamorphosis-associated endocrine events may be disrupted in caterpillars parasitized as newly moulted last (sixth) instars. Juvenile hormone (JH) titres on days 2 and 5 of the final stadium were significantly higher (> 100 fold) in parasitized than in non-parasitized hosts, in which JH was essentially absent. Elevated JH levels were associated with reduced haemolymph JH esterase (JHE) activity (down by 99.8%) and enhanced in vitro JH biosynthesis by the corpora allata (CA) (up to 4.5 fold). Wasp adults and/or larvae, in which we measured high levels of JH III (up to 2.7 ng/g), but little or no JH I or JH II, were not seen as likely sources of JH in parasitized hosts, in which we found mostly JH I and JH II. In addition, removal of parasitoid eggs or larvae after oviposition did not prevent the rise in JH titres seen in parasitoid-laden hosts, suggesting that wasp venom may be responsible for the observed hormonal dysfunction. Host haemolymph 20-hydroxyecdysone (20-E) levels were largely unaffected by parasitism during the final stadium although they were observed to increase earlier and decrease more rapidly in parasitized insects. We compare these results with those reported earlier for L. oleracea larvae parasitized by E. pennicornis as penultimate (fifth) instars, which display significantly depressed 20-E titres relative to control larvae. We conclude that E. pennicornis employs host endocrine-disruption strategies that differ according to whether the host is parasitized as a penultimate or final-stadium larva.

  12. Validation of an automatic diagnosis of strict left bundle branch block criteria using 12-lead electrocardiograms

    DEFF Research Database (Denmark)

    Xia, Xiaojuan; Ruwald, Anne-Christine; Ruwald, Martin H

    2017-01-01

    AIMS: Strict left bundle branch block (LBBB) criteria were recently proposed to identify LBBB patients to benefit most from cardiac resynchronization therapy (CRT). The aim of our study was to automate identification of strict LBBB in order to facilitate its broader application. METHODS: We devel...

  13. 7 CFR 28.416 - Strict Good Ordinary Light Spotted Color.

    Science.gov (United States)

    2010-01-01

    ... CONTAINER REGULATIONS COTTON CLASSING, TESTING, AND STANDARDS Standards Light Spotted Cotton § 28.416 Strict Good Ordinary Light Spotted Color. Strict Good Ordinary Light Spotted Color is color which in spot or... Cotton Source: 57 FR 34498, Aug. 5, 1992, unless otherwise noted. ...

  14. RH5-Basigin interaction plays a major role in the host tropism of Plasmodium falciparum.

    Science.gov (United States)

    Wanaguru, Madushi; Liu, Weimin; Hahn, Beatrice H; Rayner, Julian C; Wright, Gavin J

    2013-12-17

    Plasmodium falciparum, the cause of almost all human malaria mortality, is a member of the Laverania subgenus which infects African great apes. Interestingly, Laverania parasites exhibit strict host specificity in their natural environment: P. reichenowi, P. billcollinsi, and P. gaboni infect only chimpanzees; P. praefalciparum, P. blacklocki, and P. adleri are restricted to gorillas, and P. falciparum is pandemic in humans. The molecular mechanism(s) responsible for these host restrictions are not understood, although the interaction between the parasite blood-stage invasion ligand EBA175 and the host erythrocyte receptor Glycophorin-A (GYPA) has been implicated previously. We reexamined the role of the EBA175-GYPA interaction in host tropism using recombinant proteins and biophysical assays and found that EBA175 orthologs from the chimpanzee-restricted parasites P. reichenowi and P. billcollinsi both bound to human GYPA with affinities similar to that of P. falciparum, suggesting that the EBA175-GYPA interaction is unlikely to be the sole determinant of Laverania host specificity. We next investigated the contribution of the recently discovered Reticulocyte-binding protein Homolog 5 (RH5)-Basigin (BSG) interaction in host-species selectivity and found that P. falciparum RH5 bound chimpanzee BSG with a significantly lower affinity than human BSG and did not bind gorilla BSG, mirroring the known host tropism of P. falciparum. Using site-directed mutagenesis, we identified residues in BSG that are responsible for the species specificity of PfRH5 binding. Consistent with the essential role of the PfRH5-BSG interaction in erythrocyte invasion, we conclude that species-specific differences in the BSG receptor provide a molecular explanation for the restriction of P. falciparum to its human host.

  15. Immediate effect of instrumentation on the subgingival microflora in deep inflamed pockets under strict plaque control.

    Science.gov (United States)

    Rhemrev, G E; Timmerman, M F; Veldkamp, I; Van Winkelhoff, A J; Van der Velden, U

    2006-01-01

    To investigate (1) reduction in the number of microorganisms obtained directly after subgingival instrumentation, (2) rate of bacterial re-colonization during 2 weeks, under supragingival plaque-free conditions. Effects of subgingival instrumentation were measured at one deep pocket in 22 patients (11 smokers and 11 non-smokers). Immediately after initial therapy, experimental sites, under strict plaque control, were instrumented subgingivally. Microbiological evaluation was performed at pre-instrumentation, immediate post-instrumentation and 1 and 2 weeks post-instrumentation. Mean total anaerobic colony forming units (CFUs) dropped from 3.9 x 10(6) before to 0.09 x 10(6) immediately following instrumentation. Significant reductions were found for Tannerella forsythia, Micromonas micros, Fusobacterium nucleatum and spirochetes. Significant reductions were not observed for Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia and Campylobacter rectus. Except for spirochetes, no reduction in prevalence of specific periodontal bacteria was found immediately after instrumentation. During follow-up, mean total CFU tended to increase. Prevalence of periodontal bacteria further reduced. No effect of smoking was found. Results indicate that subgingival mechanical cleaning in itself, has a limited effect, in actually removing bacteria. The subsequent reduction in prevalence of specific periodontal bacteria shows that it is apparently difficult for these species to survive in treated pockets.

  16. Weed host specificity of the aphid, Aphis spiraecola: developmental and reproductive performance of aphids in relation to plant growth and leaf chemicals of the Siam weed, Chromolaena odorata.

    Science.gov (United States)

    Agarwala, B K; Das, Jhuma

    2012-01-01

    Density, distribution, and nutritional quality of plants are the causal basis of host plant selection in aphids. Nutritional qualities of a plant vary according to its growth stage and also in response to seasonal variation. How host plant growth stages shape aphid performance was studied in Aphis spiraecola Patch (Homoptera: Aphididae) on the perennial Siam weed, Chromolaena odorata (L.) King and Robinson (Asterales: Asteraceae). This plant species is the preferred host in the hot and humid tropical parts of northeast and southern India. Variations in developmental and reproductive performances in apterous viviparous female aphids were recorded in relation to differences in leaf chemicals in different growth stages of C. odorata. Aphids reproduced at higher rates in the vegetative stage of C. odorata when developmental time was shortest, and fecundity was higher in a longer reproductive time. Intrinsic rate of increase and net reproductive rate were also recorded to be higher in the vegetative stage of the weed host. In the vegetative stage, leaves contained higher quantity of proteins and nitrogen, which are vital for insect reproduction. Results of this study have demonstrated that A spiraecola showed synchronization of its developmental and reproductive performances to growth stages of C. odorata, which occur in high abundance in the study area.

  17. Specific glycan elements determine differential binding of individual egg glycoproteins of the human parasite Schistosoma mansoni by host C-type lectin receptors

    NARCIS (Netherlands)

    Meevissen, M.H.J.; Driessen, N.N.; Smits, H.H.; Versteegh, R.; van Vliet, S.J.; van Kooijk, Y.; Schramm, G.; Deelder, A.M.; de Haas, H.; Yazdanbakhsh, M.; Hokke, C.H.

    2012-01-01

    During infection with the blood fluke Schistosoma mansoni, glycan motifs present on glycoproteins of the parasite's eggs mediate immunomodulatory effects on the host. The recognition of these glycan motifs is primarily mediated by C-type lectin receptors on dendritic cells and other cells of the

  18. In silico target network analysis of de novo-discovered, tick saliva-specific microRNAs reveals important combinatorial effects in their interference with vertebrate host physiology

    Czech Academy of Sciences Publication Activity Database

    Hackenberg, M.; Langenberger, D.; Schwarz, Alexandra; Erhart, Jan; Kotsyfakis, Michalis

    2017-01-01

    Roč. 23, č. 8 (2017), s. 1259-1269 ISSN 1355-8382 Institutional support: RVO:60077344 Keywords : tick-vertebrate host interaction * deep- sequencing * microRNA * gene target prediction * interactomes/systems biology * disease biology Subject RIV: EB - Gene tics ; Molecular Biology OBOR OECD: Biochemistry and molecular biology Impact factor: 4.605, year: 2016

  19. Synchronization control of cross-strict feedback hyperchaotic system based on cross active backstepping design

    International Nuclear Information System (INIS)

    Wang Jing; Gao Jinfeng; Ma Xikui

    2007-01-01

    This Letter presents a novel cross active backstepping design method for synchronization control of cross-strict feedback hyperchaotic system, in which the ordinary backstepping design is unavailable. The proposed control method, combining backstepping design and active control approach, extends the application of backstepping technique in chaos control. Based on this method, different combinations of controllers can be designed to meet the needs of different applications. The proposed method is applied to achieve chaos synchronization of two identical cross-strict feedback hyperchaotic systems. Also it is used to implement synchronization between cross-strict feedback hyperchaotic system and Roessler hyperchaotic system. Numerical examples illustrate the validity of the control method

  20. Low host specificity in species-rich assemblages of xylem- and phloem-feeding herbivores (Auchenorrhyncha) in a New Guinea lowland rain forest

    Czech Academy of Sciences Publication Activity Database

    Dem, F. F.; Stewart, A. J. A.; Gibson, A.; Weiblen, G. D.; Novotný, Vojtěch

    2013-01-01

    Roč. 29, č. 6 (2013), s. 467-476 ISSN 0266-4674 R&D Projects: GA ČR GAP505/10/0673; GA MŠk(CZ) LH11008 Grant - others:GA MŠk(CZ) CZ.1.07/2.3.00/20.0064; National Science Foundation(US) DEB 0515678 Institutional support: RVO:60077344 Keywords : food web * Hemiptera * host specialization Subject RIV: EH - Ecology, Behaviour Impact factor: 1.222, year: 2013

  1. Osteoclast nuclei of myeloma patients show chromosome translocations specific for the myeloma cell clone: a new type of cancer-host partnership?

    DEFF Research Database (Denmark)

    Levin Andersen, Thomas; Boissy, Patrice; Sondergaard, T E

    2007-01-01

    A major clinical manifestation of bone cancers is bone destruction. It is widely accepted that this destruction is not caused by the malignant cells themselves, but by osteoclasts, multinucleated cells of monocytic origin that are considered to be the only cells able to degrade bone. The present...... participate directly. The possibility that malignant cells corrupt host cells by the transfer of malignant DNA may have been underestimated to date in cancer research....

  2. Native bacterial endophytes promote host growth in a species-specific manner; phytohormone manipulations do not result in common growth responses.

    Directory of Open Access Journals (Sweden)

    Hoang Hoa Long

    Full Text Available BACKGROUND: All plants in nature harbor a diverse community of endophytic bacteria which can positively affect host plant growth. Changes in plant growth frequently reflect alterations in phytohormone homoeostasis by plant-growth-promoting (PGP rhizobacteria which can decrease ethylene (ET levels enzymatically by 1-aminocyclopropane-1-carboxylate (ACC deaminase or produce indole acetic acid (IAA. Whether these common PGP mechanisms work similarly for different plant species has not been rigorously tested. METHODOLOGY/PRINCIPAL FINDINGS: We isolated bacterial endophytes from field-grown Solanum nigrum; characterized PGP traits (ACC deaminase activity, IAA production, phosphate solubilization and seedling colonization; and determined their effects on their host, S. nigrum, as well as on another Solanaceous native plant, Nicotiana attenuata. In S. nigrum, a majority of isolates that promoted root growth were associated with ACC deaminase activity and IAA production. However, in N. attenuata, IAA but not ACC deaminase activity was associated with root growth. Inoculating N. attenuata and S. nigrum with known PGP bacteria from a culture collection (DSMZ reinforced the conclusion that the PGP effects are not highly conserved. CONCLUSIONS/SIGNIFICANCE: We conclude that natural endophytic bacteria with PGP traits do not have general and predictable effects on the growth and fitness of all host plants, although the underlying mechanisms are conserved.

  3. The Effect of Strict Segregation on Pseudomonas aeruginosa in Cystic Fibrosis Patients

    NARCIS (Netherlands)

    van Mansfeld, Rosa; de Vrankrijker, Angelica; Brimicombe, Roland; Heijerman, Harry; Teding van Berkhout, Ferdinand; Spitoni, Cristian|info:eu-repo/dai/nl/304625957; Grave, Sanne; van der Ent, Cornelis; Wolfs, Tom; Willems, Rob; Bonten, Marc

    2016-01-01

    INTRODUCTION: Segregation of patients with cystic fibrosis (CF) was implemented to prevent chronic infection with epidemic Pseudomonas aeruginosa strains with presumed detrimental clinical effects, but its effectiveness has not been carefully evaluated. METHODS: The effect of strict segregation on

  4. Strict deformation quantization for actions of a class of symplectic lie groups

    International Nuclear Information System (INIS)

    Bieliavsky, Pierre; Massar, Marc

    2002-01-01

    We present explicit universal strict deformation quantization formulae for actions of Iwasawa subgroups AN of SN(1, n). This answers a question raised by Rieffel in [Contemp. Math. 228 (1998), 315]. (author)

  5. DNA remodelling by Strict Partial Endoreplication in orchids, an original process in the plant kingdom.

    Science.gov (United States)

    Brown, Spencer C; Bourge, Mickaël; Maunoury, Nicolas; Wong, Maurice; Bianchi, Michele Wolfe; Lepers-Andrzejewski, Sandra; Besse, Pascale; Siljak-Yakovlev, Sonja; Dron, Michel; Satiat-Jeunemaître, Béatrice

    2017-04-13

    DNA remodelling during endoreplication appears to be a strong developmental characteristic in orchids. In this study, we analysed DNA content and nuclei in 41 species of orchids to further map the genome evolution in this plant family. We demonstrate that the DNA remodelling observed in 36 out of 41 orchids studied corresponds to strict partial endoreplication. Such process is developmentally regulated in each wild species studied. Cytometry data analyses allowed us to propose a model where nuclear states 2C, 4E, 8E, etc. form a series comprising a fixed proportion, the euploid genome 2C, plus 2 to 32 additional copies of a complementary part of the genome. The fixed proportion ranged from 89% of the genome in Vanilla mexicana down to 19% in V. pompona, the lowest value for all 148 orchids reported. Insterspecific hybridisation did not suppress this phenomenon. Interestingly, this process was not observed in mass-produced epiphytes. Nucleolar volumes grow with the number of endocopies present, coherent with high transcription activity in endoreplicated nuclei. Our analyses suggest species-specific chromatin rearrangement. Towards understanding endoreplication, V. planifolia constitutes a tractable system for isolating the genomic sequences that confer an advantage via endoreplication from those that apparently suffice at diploid level. © The Author(s) 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  6. Generalized mechanical pain sensitivity over nerve tissues in patients with strictly unilateral migraine.

    Science.gov (United States)

    Fernández-de-las-Peñas, César; Arendt-Nielsen, Lars; Cuadrado, María Luz; Pareja, Juan A

    2009-06-01

    No study has previously analyzed pressure pain sensitivity of nerve trunks in migraine. This study aimed to examine the differences in mechanical pain sensitivity over specific nerves between patients with unilateral migraine and healthy controls. Blinded investigators assessed pressure pain thresholds (PPT) over the supra-orbital nerves (V1) and peripheral nerve trunks of both upper extremities (median, radial, and ulnar nerves) in 20 patients with strictly unilateral migraine and 20 healthy matched controls. Pain intensity after palpation over both supra-orbital nerves was also assessed. A pressure algometer was used to quantify PPT, whereas a 10-point numerical pain rate scale was used to evaluate pain to palpation over the supra-orbital nerve. The analysis of covariance revealed that pain to palpation over the supra-orbital nerve was significantly higher (P0.6). In patients with unilateral migraine, we found increased mechano-sensitivity of the supra-orbital nerve on the symptomatic side of the head. Outside the head, the same patients showed increased mechano-sensitivity of the main peripheral nerves of both upper limbs, without asymmetries. Such diffuse hypersensitivity of the peripheral nerves lends further evidence to the presence of a state of hyperexcitability of the central nervous system in patients with unilateral migraine.

  7. Strict optical orthogonal codes for purely asynchronous code-division multiple-access applications

    Science.gov (United States)

    Zhang, Jian-Guo

    1996-12-01

    Strict optical orthogonal codes are presented for purely asynchronous optical code-division multiple-access (CDMA) applications. The proposed code can strictly guarantee the peaks of its cross-correlation functions and the sidelobes of any of its autocorrelation functions to have a value of 1 in purely asynchronous data communications. The basic theory of the proposed codes is given. An experiment on optical CDMA systems is also demonstrated to verify the characteristics of the proposed code.

  8. Plant use in the medicinal practices known as "strict diets" in Chazuta valley (Peruvian Amazon).

    Science.gov (United States)

    Sanz-Biset, Jaume; Cañigueral, Salvador

    2011-09-01

    Strict diets are traditional medicinal practices where plant remedies are consumed with nearly fasting and with some sort of social seclusion. The aim of this work was to describe these practices of Chazuta and the use of plants within, as well as to analyse the possible functions of the last. The information was obtained through interviews to the 6.3% of the district rural adult population (140 individuals, 75% of which was considered Quechua). In total, 122 strict diets were recorded and 106 different plant species were reported to be used. Strict diets present a characteristic structure and plant use. The main effects reported in strict diets were antinflammatory, antiinfective, brain function alteration and depuration. Strict diets are well structured traditional medicinal practices, also with a symbolic significance in the life cycle of chazutian men. Plants used in strict diets can contribute to the main effects through antinflammation, antiinfective actions, psychoactivity and depurative related activities. The correlation between literature evidence of activity of most used plants and effects reported for the correspondent diet (i.e. in which the plant was used) are 36% for antinflammatory activity, 29% for antimicrobial activity, 18% for psychoactivity and 5% for depurative related activities. The percentages go to 77%, 64%, 73% and 32%, respectively, when literature evidences on related taxa are also considered. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  9. Molecular analysis of the early interaction between the grapevine flower and Botrytis cinerea reveals that prompt activation of specific host pathways leads to fungus quiescence.

    Science.gov (United States)

    Haile, Zeraye Mehari; Pilati, Stefania; Sonego, Paolo; Malacarne, Giulia; Vrhovsek, Urska; Engelen, Kristof; Tudzynski, Paul; Zottini, Michela; Baraldi, Elena; Moser, Claudio

    2017-08-01

    Grape quality and yield can be impaired by bunch rot, caused by the necrotrophic fungus Botrytis cinerea. Infection often occurs at flowering, and the pathogen stays quiescent until fruit maturity. Here, we report a molecular analysis of the early interaction between B. cinerea and Vitis vinifera flowers, using a controlled infection system, confocal microscopy and integrated transcriptomic and metabolic analysis of the host and the pathogen. Flowers from fruiting cuttings of the cultivar Pinot Noir were infected with green fluorescent protein (GFP)-labelled B. cinerea and studied at 24 and 96 hours post-inoculation (h.p.i.). We observed that penetration of the epidermis by B. cinerea coincided with increased expression of genes encoding cell-wall-degrading enzymes, phytotoxins and proteases. Grapevine responded with a rapid defence reaction involving 1193 genes associated with the accumulation of antimicrobial proteins, polyphenols, reactive oxygen species and cell wall reinforcement. At 96 h.p.i., the reaction appears largely diminished both in the host and in the pathogen. Our data indicate that the defence responses of the grapevine flower collectively are able to restrict invasive fungal growth into the underlying tissues, thereby forcing the fungus to enter quiescence until the conditions become more favourable to resume pathogenic development. © 2017 John Wiley & Sons Ltd.

  10. The Drosophila melanogaster host model

    Science.gov (United States)

    Igboin, Christina O.; Griffen, Ann L.; Leys, Eugene J.

    2012-01-01

    The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed. PMID:22368770

  11. Comparing mechanisms of host manipulation across host and parasite taxa

    Science.gov (United States)

    Lafferty, Kevin D.; Shaw, Jenny C.

    2013-01-01

    Parasites affect host behavior in several ways. They can alter activity, microhabitats or both. For trophically transmitted parasites (the focus of our study), decreased activity might impair the ability of hosts to respond to final-host predators, and increased activity and altered microhabitat choice might increase contact rates between hosts and final-host predators. In an analysis of trophically transmitted parasites, more parasite groups altered activity than altered microhabitat choice. Parasites that infected vertebrates were more likely to impair the host’s reaction to predators, whereas parasites that infected invertebrates were more likely to increase the host’s contact with predators. The site of infection might affect how parasites manipulate their hosts. For instance, parasites in the central nervous system seem particularly suited to manipulating host behavior. Manipulative parasites commonly occupy the body cavity, muscles and central nervous systems of their hosts. Acanthocephalans in the data set differed from other taxa in that they occurred exclusively in the body cavity of invertebrates. In addition, they were more likely to alter microhabitat choice than activity. Parasites in the body cavity (across parasite types) were more likely to be associated with increased host contact with predators. Parasites can manipulate the host through energetic drain, but most parasites use more sophisticated means. For instance, parasites target four physiological systems that shape behavior in both invertebrates and vertebrates: neural, endocrine, neuromodulatory and immunomodulatory. The interconnections between these systems make it difficult to isolate specific mechanisms of host behavioral manipulation.

  12. Recombinant Helicoverpa armigera nucleopolyhedrovirus with arthropod-specific neurotoxin gene RjAa17f from Rhopalurus junceus enhances the virulence against the host larvae.

    Science.gov (United States)

    Yu, Huan; Zhou, Bin; Meng, Jiao; Xu, Jian; Liu, Tong-Xian; Wang, Dun

    2017-06-01

    A recombinant Helicoverpa armigera nucleopolyhedrovirus (HearNPV) expressing the insect-selective neurotoxin (RjAa17f) from Cuban scorpion Rhopalurus junceus was constructed by replacing the UDP-glucosyltransferase gene (egt) using λ-red homologous recombination system. Another egt deleted control HearNPV was constructed in a similar way by inserting egfp gene into the egt locus. One-step viral growth curve and viral DNA replication curve analysis confirmed that the recombination did not affect the viral growth and DNA replication in host cells. There is no discernable difference in occlusion-body morphogenesis between RjAa17f-HearNPV, Egfp-HearNPV and HZ8-HearNPV, which was confirmed by transmission electron microscopy analysis. However, the insecticidal activity of RjAa17f-HearNPV is enhanced against the third instar H. armigera larvae according to the bioassay on virulence comparison. There is a dramatic reduction (56.9%) in median lethal dose (LD 50 ) and also a reduction (13.4%) in median survival time (ST 50 ) for the recombinant RjAa17f-HearNPV compared to the HZ8-HearNPV, but only a 27.5% reduction in LD 50 and 10.1% reduction in ST 50 value when Egfp-HearNPV is compared with HZ8-HearNPV. The daily diet consumption analysis showed that the RjAa17f-HearNPV was able to inhibit the infected larvae feeding compared with the egt minus HearNPV. These results demonstrated that this novel recombinant RjAa17f-HearNPV could improve the insecticidal effect against its host insects and RjAa17f could be a considerable candidate for other recombinant baculovirus constructions. © 2015 Institute of Zoology, Chinese Academy of Sciences.

  13. Fungal sensing of host environment.

    Science.gov (United States)

    Braunsdorf, C; Mailänder-Sánchez, D; Schaller, M

    2016-09-01

    To survive inside a host, fungi have to adapt to a changing and often hostile environment and therefore need the ability to recognize what is going on around them. To adapt to different host niches, they need to sense external conditions such as temperature, pH and to recognize specific host factors. The ability to respond to physiological changes inside the host, independent of being in a commensal, pathogenic or even symbiotic context, implicates mechanisms for sensing of specific host factors. Because the cell wall is constantly in contact with the surrounding, fungi express receptors on the surface of their cell wall, such as pheromone receptors, which have important roles, besides mediating chemotropism for mating. We are not restricting the discussion to the human host because the receptors and mechanisms used by different fungal species to sense their environment are often similar even for plant pathogens. Furthermore, the natural habitat of opportunistic pathogenic fungi with the potential to cause infection in a human host is in soil and on plants. While the hosts' mechanisms of sensing fungal pathogens have been addressed in the literature, the focus of this review is to fill the gap, giving an overview on fungal sensing of a host-(ile) environment. Expanding our knowledge on host-fungal interactions is extremely important to prevent and treat diseases of pathogenic fungi, which are important issues in human health and agriculture but also to understand the delicate balance of fungal symbionts in our ecosystem. © 2016 John Wiley & Sons Ltd.

  14. Investigation of prevalence of free Shiga toxin-producing Escherichia coli (STEC)-specific bacteriophages and its correlation with STEC bacterial hosts in a produce-growing area in Salinas, California.

    Science.gov (United States)

    Liao, Yen-Te; Quintela, Irwin A; Nguyen, Kimberly; Salvador, Alexandra; Cooley, Michael B; Wu, Vivian C H

    2018-01-01

    Shiga toxin-producing E. coli (STEC) causes approximately 265,000 illnesses and 3,600 hospitalizations annually and is highly associated with animal contamination due to the natural reservoir of ruminant gastrointestinal tracts. Free STEC-specific bacteriophages against STEC strains are also commonly isolated from fecal-contaminated environment. Previous studies have evaluated the correlation between the prevalence of STEC-specific bacteriophages and STEC strains to improve animal-associated environment. However, the similar information regarding free STEC-specific bacteriophages prevalence in produce growing area is lacking. Thus, the objectives of this research were to determine the prevalence of STEC-specific phages, analyze potential effects of environmental factors on the prevalence of the phages, and study correlations between STEC-specific bacteriophages and the bacterial hosts in pre-harvest produce environment. Surface water from 20 samples sites was subjected to free bacteriophage isolation using host strains of both generic E. coli and STEC (O157, six non-O157 and one O179 strains) cocktails, and isolation of O157 and non-O157 STEC strains by use of culture methods combined with PCR-based confirmation. The weather data were obtained from weather station website. Free O145- and O179-specific bacteriophages were the two most frequently isolated bacteriophages among all (O45, O145, O157 and O179) in this study. The results showed June and July had relatively high prevalence of overall STEC-specific bacteriophages with minimum isolation of STEC strains. In addition, the bacteriophages were likely isolated in the area-around or within city-with predominant human impact, whereas the STEC bacterial isolates were commonly found in agriculture impact environment. Furthermore, there was a trend that the sample sites with positive of free STEC bacteriophage did not have the specific STEC bacterial hosts. The findings of the study enable us to understand the ecology

  15. Actions of a separately strict cpo-monoid on pointed directed complete posets

    Directory of Open Access Journals (Sweden)

    Halimeh Moghbeli Damaneh

    2015-07-01

    Full Text Available ‎ In the present article‎, ‎we study some categorical properties of the category {$bf‎ Cpo_{Sep}$-$S$} of all {separately strict $S$-cpo's}; cpo's equipped with‎ a compatible right action of a separately strict cpo-monoid $S$ which is‎ strict continuous in each component‎. ‎In particular‎, we show that this category is reflective and coreflective in the‎ category of $S$-cpo's‎, ‎find the free and cofree functors‎, characterize products and coproducts‎. ‎Furthermore‎, ‎epimorphisms and‎  monomorphisms in {$bf Cpo_{Sep}$-$S$} are studied‎, ‎and show that‎ {$bf Cpo_{Sep}$-$S$} is not cartesian closed‎.

  16. RH5–Basigin interaction plays a major role in the host tropism of Plasmodium falciparum

    Science.gov (United States)

    Wanaguru, Madushi; Liu, Weimin; Hahn, Beatrice H.; Rayner, Julian C.; Wright, Gavin J.

    2013-01-01

    Plasmodium falciparum, the cause of almost all human malaria mortality, is a member of the Laverania subgenus which infects African great apes. Interestingly, Laverania parasites exhibit strict host specificity in their natural environment: P. reichenowi, P. billcollinsi, and P. gaboni infect only chimpanzees; P. praefalciparum, P. blacklocki, and P. adleri are restricted to gorillas, and P. falciparum is pandemic in humans. The molecular mechanism(s) responsible for these host restrictions are not understood, although the interaction between the parasite blood-stage invasion ligand EBA175 and the host erythrocyte receptor Glycophorin-A (GYPA) has been implicated previously. We reexamined the role of the EBA175–GYPA interaction in host tropism using recombinant proteins and biophysical assays and found that EBA175 orthologs from the chimpanzee-restricted parasites P. reichenowi and P. billcollinsi both bound to human GYPA with affinities similar to that of P. falciparum, suggesting that the EBA175–GYPA interaction is unlikely to be the sole determinant of Laverania host specificity. We next investigated the contribution of the recently discovered Reticulocyte-binding protein Homolog 5 (RH5)–Basigin (BSG) interaction in host-species selectivity and found that P. falciparum RH5 bound chimpanzee BSG with a significantly lower affinity than human BSG and did not bind gorilla BSG, mirroring the known host tropism of P. falciparum. Using site-directed mutagenesis, we identified residues in BSG that are responsible for the species specificity of PfRH5 binding. Consistent with the essential role of the PfRH5–BSG interaction in erythrocyte invasion, we conclude that species-specific differences in the BSG receptor provide a molecular explanation for the restriction of P. falciparum to its human host. PMID:24297912

  17. Excretory products of the cestode, Schistocephalus solidus, modulate in vitro responses of leukocytes from its specific host, the three-spined stickleback (Gasterosteus aculeatus).

    Science.gov (United States)

    Scharsack, Jörn Peter; Gossens, Anabel; Franke, Frederik; Kurtz, Joachim

    2013-12-01

    Helminth parasites have evolved remarkable strategies to manipulate the immune system of their hosts. During infections of three-spined stickleback (Gasterosteus aculeatus) with the cestode Schistocephalus solidus prominent immunological changes occur, presumably due to manipulative activity of the parasite. We hypothesise that excretory/secretory products of the parasite are involved in the manipulation of the stickleback's immune system and that this may depend on the individual parasite and its origin. We therefore produced S. solidus conditioned cell culture media (SSCM) with parasites from different origins (Norway, Spain and Germany) and exposed head kidney leukocytes (HKL) from un-infected sticklebacks in cell cultures to SSCM. After in vitro culture, HKL were subjected to differential cell counts (granulocytes/lymphocytes) by means of flow cytometry. Leukocyte sub-populations were analysed for cell viability and changes in cell morphology. The respiratory burst activity was measured with a luminescence assay. Exposure of HKL to SSCM induced an up-regulation of respiratory burst activity after already 1 h, which was still elevated at 24 h, but which was in some cases significantly down-regulated after 96 h. Respiratory burst was positively correlated with the number of live granulocytes in the culture, suggesting that the respiratory burst activity was changed by SSCM effects on granulocyte viability. After 1 h and 24 h of HKL culture, no lymphocyte responses to SSCM were detectable, but after 96 h lymphocyte viability was significantly decreased with SSCM from Spanish S. solidus. In these cultures, residual lymphocytes increased in size, suggesting that cell death and activation might have occurred in parallel. The highest respiratory burst activity was induced by SSCM from Spanish parasites, in particular when they were grown in sympatric sticklebacks. The in vitro HKL responses to SSCM depended on the individual parasite and its population of origin

  18. The photon is no strict particle and nonlocality is far from being proven

    Energy Technology Data Exchange (ETDEWEB)

    Greulich, Karl Otto [Fritz Lipmann Institut, Jena (Germany)

    2010-07-01

    Two aspects of philosophical discussions on physics are the wave particle dualism and non locality including entanglement. However the strict particle aspect of the photon, in the common sense view, has never been proven. The accumulation time argument, the only experimental verification of a strictly particle like photon, has so far not yet been satisfied. Also, experiments thought to prove nonlocality have loophole which have so far not yet been safely closed, and now an even more serious loophole emerges. Thus, also nonlocality cannot be seen as proven. This demands some fine tuning of philosophical discussions on critical experiments in physics.

  19. Host genetics affect microbial ecosystems via host immunity.

    Science.gov (United States)

    El Kafsi, Hela; Gorochov, Guy; Larsen, Martin

    2016-10-01

    Genetic evolution of multicellular organisms has occurred in response to environmental challenges, including competition for nutrients, climate change, physical and chemical stressors, and pathogens. However, fitness of an organism is dependent not only on defense efficacy, but also on the ability to take advantage of symbiotic organisms. Indeed, microbes not only encompass pathogenicity, but also enable efficient nutrient uptake from diets nondegradable by the host itself. Moreover, microbes play important roles in the development of host immunity. Here we review associations between specific host genes and variance in microbiota composition and compare with interactions between microbes and host immunity. Recent genome-wide association studies reveal that symbiosis between host and microbiota is the exquisite result of genetic coevolution. Moreover, a subset of microbes from human and mouse microbiota have been identified to interact with humoral and cellular immunity. Interestingly, microbes associated with both host genetics and host immunity are taxonomically related. Most involved are Bifidobacterium, Lactobacillus, and Akkermansia, which are dually associated with both host immunity and host genetics. We conclude that future therapeutics targeting microbiota in the context of chronic inflammatory diseases need to consider both immune and genetic host features associated with microbiota homeostasis.

  20. Relative expression of bacterial and host specific genes associated with probiotic survival and viability in the mice gut fed with Lactobacillus plantarum Lp91.

    Science.gov (United States)

    Chandran, Archana; Duary, Raj Kumar; Grover, Sunita; Batish, Virender Kumar

    2013-11-07

    The present investigation was aimed at studying the relative expression of atpD (a key part of F1F0-ATPase operon), bsh (bile salt hydrolase), mub (mucus-binding protein) and MUC2 (mucin) genes in mouse model for establishing the in vivo functional efficacy of Lactobacillus plantarum Lp91 (MTCC5690) by reverse transcription-quantitative PCR (RT-qPCR). The atpD gene was significantly up-regulated to 2.0, 2.4 and 3.2 folds in Lp91 after 15, 30 and 60 min transit in the stomach of mice. The maximal significant (Pstrain Lp5276 after seven days of mice feeding. Simultaneously, mub gene expression increased to 12.8 and 22.7 fold in both Lp91 and Lp5276, respectively. The expression level of MUC2 was at the level of 1.6 and 2.1 fold in the host colon on administration with Lp91 and Lp5276 feeding, respectively. Hence, the expression of atpD, bsh, mub, MUC2 could be considered as prospective and potential biomarkers for screening of novel probiotic lactobacillus strains for optimal functionality in the gut. Copyright © 2013 Elsevier GmbH. All rights reserved.

  1. Analysis of nuclear and organellar genomes of Plasmodium knowlesi in humans reveals ancient population structure and recent recombination among host-specific subpopulations

    KAUST Repository

    Diez Benavente, Ernest

    2017-09-18

    The macaque parasite Plasmodium knowlesi is a significant concern in Malaysia where cases of human infection are increasing. Parasites infecting humans originate from genetically distinct subpopulations associated with the long-tailed (Macaca fascicularis (Mf)) or pig-tailed macaques (Macaca nemestrina (Mn)). We used a new high-quality reference genome to re-evaluate previously described subpopulations among human and macaque isolates from Malaysian-Borneo and Peninsular-Malaysia. Nuclear genomes were dimorphic, as expected, but new evidence of chromosomal-segment exchanges between subpopulations was found. A large segment on chromosome 8 originating from the Mn subpopulation and containing genes encoding proteins expressed in mosquito-borne parasite stages, was found in Mf genotypes. By contrast, non-recombining organelle genomes partitioned into 3 deeply branched lineages, unlinked with nuclear genomic dimorphism. Subpopulations which diverged in isolation have re-connected, possibly due to deforestation and disruption of wild macaque habitats. The resulting genomic mosaics reveal traits selected by host-vector-parasite interactions in a setting of ecological transition.

  2. The Importance of the KR-Rich Region of the Coat Protein of Ourmia melon virus for Host Specificity, Tissue Tropism, and Interference With Antiviral Defense.

    Science.gov (United States)

    Rossi, Marika; Vallino, Marta; Abbà, Simona; Ciuffo, Marina; Balestrini, Raffaella; Genre, Andrea; Turina, Massimo

    2015-01-01

    The N-terminal region of the Ourmia melon virus (OuMV) coat protein (CP) contains a short lysine/arginine-rich (KR) region. By alanine scanning mutagenesis, we showed that the KR region influences pathogenicity and virulence of OuMV without altering viral particle assembly. A mutant, called OuMV6710, with three basic residue substitutions in the KR region, was impaired in the ability to maintain the initial systemic infection in Nicotiana benthamiana and to infect both cucumber and melon plants systemically. The integrity of this protein region was also crucial for encapsidation of viral genomic RNA; in fact, certain mutations within the KR region partially compromised the RNA encapsidation efficiency of the CP. In Arabidopsis thaliana Col-0, OuMV6710 was impaired in particle accumulation; however, this phenotype was abolished in dcl2/dcl4 and dcl2/dcl3/dcl4 Arabidopsis mutants defective for antiviral silencing. Moreover, in contrast to CPwt, in situ immunolocalization experiments indicated that CP6710 accumulates efficiently in the spongy mesophyll tissue of infected N. benthamiana and A. thaliana leaves but only occasionally infects palisade tissues. These results provided strong evidence of a crucial role for OuMV CP during viral infection and highlighted the relevance of the KR region in determining tissue tropism, host range, pathogenicity, and RNA affinity, which may be all correlated with a possible CP silencing-suppression activity.

  3. Bat lung epithelial cells show greater host species-specific innate resistance than MDCK cells to human and avian influenza viruses.

    Science.gov (United States)

    Slater, Tessa; Eckerle, Isabella; Chang, Kin-Chow

    2018-04-10

    With the recent discovery of novel H17N10 and H18N11 influenza viral RNA in bats and report on high frequency of avian H9 seroconversion in a species of free ranging bats, an important issue to address is the extent bats are susceptible to conventional avian and human influenza A viruses. To this end, three bat species (Eidolon helvum, Carollia perspicillata and Tadarida brasiliensis) of lung epithelial cells were separately infected with two avian and two human influenza viruses to determine their relative host innate immune resistance to infection. All three species of bat cells were more resistant than positive control Madin-Darby canine kidney (MDCK) cells to all four influenza viruses. TB1-Lu cells lacked sialic acid α2,6-Gal receptors and were most resistant among the three bat species. Interestingly, avian viruses were relatively more replication permissive in all three bat species of cells than with the use of human viruses which suggest that bats could potentially play a role in the ecology of avian influenza viruses. Chemical inhibition of the JAK-STAT pathway in bat cells had no effect on virus production suggesting that type I interferon signalling is not a major factor in resisting influenza virus infection. Although all three species of bat cells are relatively more resistant to influenza virus infection than control MDCK cells, they are more permissive to avian than human viruses which suggest that bats could have a contributory role in the ecology of avian influenza viruses.

  4. Vitronectin Binds to a Specific Stretch within the Head Region of Yersinia Adhesin A and Thereby Modulates Yersinia enterocolitica Host Interaction.

    Science.gov (United States)

    Mühlenkamp, Melanie C; Hallström, Teresia; Autenrieth, Ingo B; Bohn, Erwin; Linke, Dirk; Rinker, Janina; Riesbeck, Kristian; Singh, Birendra; Leo, Jack C; Hammerschmidt, Sven; Zipfel, Peter F; Schütz, Monika S

    2017-01-01

    Complement resistance is an important virulence trait of Yersinia enterocolitica (Ye). The predominant virulence factor expressed by Ye is Yersinia adhesin A (YadA), which enables bacterial attachment to host cells and extracellular matrix and additionally allows the acquisition of soluble serum factors. The serum glycoprotein vitronectin (Vn) acts as an inhibitory regulator of the terminal complement complex by inhibiting the lytic pore formation. Here, we show YadA-mediated direct interaction of Ye with Vn and investigated the role of this Vn binding during mouse infection in vivo. Using different Yersinia strains, we identified a short stretch in the YadA head domain of Ye O:9 E40, similar to the 'uptake region' of Y. pseudotuberculosis YPIII YadA, as crucial for efficient Vn binding. Using recombinant fragments of Vn, we found the C-terminal part of Vn, including heparin-binding domain 3, to be responsible for binding to YadA. Moreover, we found that Vn bound to the bacterial surface is still functionally active and thus inhibits C5b-9 formation. In a mouse infection model, we demonstrate that Vn reduces complement-mediated killing of Ye O:9 E40 and, thus, improved bacterial survival. Taken together, these findings show that YadA-mediated Vn binding influences Ye pathogenesis. © 2016 S. Karger AG, Basel.

  5. More strictly protected areas are not necessarily more protective: evidence from Bolivia, Costa Rica, Indonesia, and Thailand

    International Nuclear Information System (INIS)

    Ferraro, Paul J; Hanauer, Merlin M; Miteva, Daniela A; Pattanayak, Subhrendu K; Canavire-Bacarreza, Gustavo Javier; Sims, Katharine R E

    2013-01-01

    National parks and other protected areas are at the forefront of global efforts to protect biodiversity and ecosystem services. However, not all protection is equal. Some areas are assigned strict legal protection that permits few extractive human uses. Other protected area designations permit a wider range of uses. Whether strictly protected areas are more effective in achieving environmental objectives is an empirical question: although strictly protected areas legally permit less anthropogenic disturbance, the social conflicts associated with assigning strict protection may lead politicians to assign strict protection to less-threatened areas and may lead citizens or enforcement agents to ignore the strict legal restrictions. We contrast the impacts of strictly and less strictly protected areas in four countries using IUCN designations to measure de jure strictness, data on deforestation to measure outcomes, and a quasi-experimental design to estimate impacts. On average, stricter protection reduced deforestation rates more than less strict protection, but the additional impact was not always large and sometimes arose because of where stricter protection was assigned rather than regulatory strictness per se. We also show that, in protected area studies contrasting y management regimes, there are y 2 policy-relevant impacts, rather than only y, as earlier studies have implied. (letter)

  6. Fasciola hepatica: comparative effects of host resistance and parasite intra-specific interactions on size and reproductive histology in flukes from rats infected with isolates differing in triclabendazole sensitivity.

    Science.gov (United States)

    Hanna, R E B; Gordon, A W; Moffett, D; Edgar, H W J; Oliver, L F; McConnell, S; Shaw, L; Brennan, G P; Fairweather, I

    2011-06-10

    The efficacies of putative fasciolicides and vaccines against Fasciola hepatica are frequently monitored in clinical and field trials by determination of fluke egg output in host faeces and by worm counts in the host liver at autopsy. Less often used are parameters based on fluke size and histology, yet these can provide important indications of specific effects on the development of particular germ-line or somatic tissues, especially in relation to the timing and profligacy of egg production. In this study, F. hepatica metacercariae of two distinct isolates, the triclabendazole (TCBZ)-sensitive Cullompton isolate and the TCBZ-resistant Oberon isolate, were administered to rats as single-isolate or mixed-isolate infections. At autopsy 16 weeks later individual adult flukes were counted, measured and the reproductive organs were examined histologically. The degree of development of the testis tubules in each fluke was represented by a numerical score, based on the proportion of the histological section profiles occupied by testis tissue. The level of anti-F. hepatica antibody in the serum of each rat was determined by ELISA. It was found that Cullompton flukes were significantly larger than Oberon flukes, and that significantly more Cullompton metacercariae developed to adults than Oberon metacercariae. The Cullompton flukes showed histological evidence of aspermy and spermatogenic arrest, which was reflected in quantitatively reduced testicular development, as compared with the Oberon isolate. In Cullompton flukes, parthenogenetic egg development is implied. The size of Cullompton and Oberon flukes was significantly related to the number of adult flukes recovered, to the number of metacercariae administered, and to the percentage success of infection. The testis development score in both isolates was significantly related to the number of adult flukes recovered but not to the number of metacercariae administered, or to the percentage success of infection. Fluke

  7. Reduced susceptibility of tomato stem to the necrotrophic fungus Botrytis cinerea is associated with a specific adjustment of fructose content in the host sugar pool.

    Science.gov (United States)

    Lecompte, François; Nicot, Philippe C; Ripoll, Julie; Abro, Manzoor A; Raimbault, Astrid K; Lopez-Lauri, Félicie; Bertin, Nadia

    2017-03-01

    Plant soluble sugars, as main components of primary metabolism, are thought to be implicated in defence against pathogenic fungi. However, the function of sucrose and hexoses remains unclear. This study aimed to identify robust patterns in the dynamics of soluble sugars in sink tissues of tomato plants during the course of infection by the necrotrophic fungus Botrytis cinerea . Distinct roles for glucose and fructose in defence against B. cinerea were hypothesized. We examined sugar contents and defence hormonal markers in tomato stem tissues before and after infection by B. cinerea , in a range of abiotic environments created by various nitrogen and water supplies. Limited nitrogen or water supplies increased tomato stem susceptibility to B. cinerea . Glucose and fructose contents of tissues surrounding infection sites evolved differently after inoculation. The fructose content never decreased after inoculation with B. cinerea , while that of glucose showed either positive or negative variation, depending on the abiotic environment. An increase in the relative fructose content (defined as the proportion of fructose in the soluble sugar pool) was observed in the absence of glucose accumulation and was associated with lower susceptibility. A lower expression of the salicylic acid marker PR1a , and a lower repression of a jasmonate marker COI1 were associated with reduced susceptibility. Accordingly, COI1 expression was positively correlated with the relative fructose contents 7 d after infection. Small variations of fructose content among the sugar pool are unlikely to affect intrinsic pathogen growth. Our results highlight distinct use of host glucose and fructose after infection by B. cinerea and suggest strongly that adjustment of the relative fructose content is required for enhanced plant defence. © The Author 2017. Published by Oxford University Press on behalf of the Annals of Botany Company.

  8. Female-induced increase of host-plant volatiles enhance specific attraction of aphid male Dysaphis plantaginea (Homoptera: Aphididae) to the sex pheromone

    NARCIS (Netherlands)

    Tol, van R.W.H.M.; Helsen, H.H.M.; Griepink, F.C.; Kogel, de W.J.

    2009-01-01

    All aphid species studied so far share the same sex pheromone components, nepetalactol and nepetalactone. Variation by different enantiomers and blends of the two components released by different aphid species are limited and can only partially explain species-specific attraction of males to

  9. Distribution, host specificity, and the potential for cryptic speciation in hoverfly Microdon myrmicae (Diptera: Syrphidae), a social parasite of Myrmica ants

    DEFF Research Database (Denmark)

    Bonelli, Simona; Witek, Magdalena; Canterino, Sara

    2011-01-01

    1. In 2002 Microdon myrmicae, a social parasite of Myrmica ants, was taxonomically separated from Microdon mutabilis. The original study in the U.K. found Microdon myrmicae to be specific to one ant species, Myrmica scabrinodis, yet it became apparent that the range of Microdon myrmicae includes ...

  10. Strict Monotonicity and Unique Continuation for the Third-Order Spectrum of Biharmonic Operator

    Directory of Open Access Journals (Sweden)

    Khalil Ben Haddouch

    2012-01-01

    Full Text Available We will study the spectrum for the biharmonic operator involving the laplacian and the gradient of the laplacian with weight, which we call third-order spectrum. We will show that the strict monotonicity of the eigenvalues of the operator , where , holds if some unique continuation property is satisfied by the corresponding eigenfunctions.

  11. "Let the Master Respond": Should Schools Be Strictly Liable When Employees Sexually Abuse Children?

    Science.gov (United States)

    Fossey, Richard; DeMitchell, Todd

    Although sexual abuse against children is a problem in the public schools, school officials have generally not acted aggressively to stop it. This paper argues for a strict liability standard--the assessment of liability without fault--against a school district in cases of student sexual abuse by a school employee. Part 1 explores the principle of…

  12. Detection of low numbers of microplastics in North Sea fish using strict quality assurance criteria

    NARCIS (Netherlands)

    Hermsen, E.; Pompe, R.; Besseling, E.; Koelmans, A.A.

    2017-01-01

    We investigated 400 individual fish of four North Sea species: Atlantic Herring, Sprat, Common Dab, and Whiting on ingestion of > 20 μm microplastic. Strict quality assurance criteria were followed in order to control contamination during the study. Two plastic particles were found in only 1 (a

  13. History, administration, goals, values, and long-term data of Russia's strictly protected scientific nature reserves

    Science.gov (United States)

    Martin A. Spetich; Anna E. Kvashnina; Y.D. Nukhimovskya; Olin E. Jr. Rhodes

    2009-01-01

    One of the most comprehensive attempts at biodiversity conservation in Russia and the former Soviet Union has been the establishment of an extensive network of protected natural areas. Among all types of protected areas in Russia, zapovedniks (strictly protected scientific preserve) have been the most effective in protecting biodiversity at the ecosystem scale. Russia...

  14. The Preventive Effect of Strict Gun Control Laws on Suicide and Homicide.

    Science.gov (United States)

    Lester, David; Murrell, Mary E.

    1982-01-01

    Examined state gun control laws and used a multidimensional scaling technique to study the relationship of strictness and death rates. Results showed states with stricter laws had lower suicide rates by firearms but higher rates by other means. No effect on homicide was found. (JAC)

  15. Functional characterization of the Mycobacterium abscessus genome coupled with condition specific transcriptomics reveals conserved molecular strategies for host adaptation and persistence.

    Science.gov (United States)

    Miranda-CasoLuengo, Aleksandra A; Staunton, Patrick M; Dinan, Adam M; Lohan, Amanda J; Loftus, Brendan J

    2016-08-05

    Mycobacterium abscessus subsp. abscessus (MAB) is a highly drug resistant mycobacterium and the most common respiratory pathogen among the rapidly growing non-tuberculous mycobacteria. MAB is also one of the most deadly of the emerging cystic fibrosis (CF) pathogens requiring prolonged treatment with multiple antibiotics. In addition to its "mycobacterial" virulence genes, the genome of MAB harbours a large accessory genome, presumably acquired via lateral gene transfer including homologs shared with the CF pathogens Pseudomonas aeruginosa and Burkholderia cepacia. While multiple genome sequences are available there is little functional genomics data available for this important pathogen. We report here the first multi-omics approach to characterize the primary transcriptome, coding potential and potential regulatory regions of the MAB genome utilizing differential RNA sequencing (dRNA-seq), RNA-seq, Ribosome profiling and LC-MS proteomics. In addition we attempt to address the genomes contribution to the molecular systems that underlie MAB's adaptation and persistence in the human host through an examination of MABs transcriptional response to a number of clinically relevant conditions. These include hypoxia, exposure to sub-inhibitory concentrations of antibiotics and growth in an artificial sputum designed to mimic the conditions within the cystic fibrosis lung. Our integrated map provides the first comprehensive view of the primary transcriptome of MAB and evidence for the translation of over one hundred new short open reading frames (sORFs). Our map will act as a resource for ongoing functional genomics characterization of MAB and our transcriptome data from clinically relevant stresses informs our understanding of MAB's adaptation to life in the CF lung. MAB's adaptation to growth in artificial CF sputum highlights shared metabolic strategies with other CF pathogens including P. aeruginosa and mirrors the transcriptional responses that lead to persistence in

  16. Novel microsatellite DNA markers indicate strict parthenogenesis and few genotypes in the invasive willow sawfly Nematus oligospilus.

    Science.gov (United States)

    Caron, V; Norgate, M; Ede, F J; Nyman, T; Sunnucks, P

    2013-02-01

    Invasive organisms can have major impacts on the environment. Some invasive organisms are parthenogenetic in their invasive range and, therefore, exist as a number of asexual lineages (=clones). Determining the reproductive mode of invasive species has important implications for understanding the evolutionary genetics of such species, more especially, for management-relevant traits. The willow sawfly Nematus oligospilus Förster (Hymenoptera: Tenthredinidae) has been introduced unintentionally into several countries in the Southern Hemisphere where it has subsequently become invasive. To assess the population expansion, reproductive mode and host-plant relationships of this insect, microsatellite markers were developed and applied to natural populations sampled from the native and expanded range, along with sequencing of the cytochrome-oxidase I mitochondrial DNA (mtDNA) region. Other tenthredinids across a spectrum of taxonomic similarity to N. oligospilus and having a range of life strategies were also tested. Strict parthenogenesis was apparent within invasive N. oligospilus populations throughout the Southern Hemisphere, which comprised only a small number of genotypes. Sequences of mtDNA were identical for all individuals tested in the invasive range. The microsatellite markers were used successfully in several sawfly species, especially Nematus spp. and other genera of the Nematini tribe, with the degree of success inversely related to genetic divergence as estimated from COI sequences. The confirmation of parthenogenetic reproduction in N. oligospilus and the fact that it has a very limited pool of genotypes have important implications for understanding and managing this species and its biology, including in terms of phenotypic diversity, host relationships, implications for spread and future adaptive change. It would appear to be an excellent model study system for understanding evolution of invasive parthenogens that diverge without sexual reproduction and

  17. Yersinia enterocolitica-Specific Infection by Bacteriophages TG1 and ϕR1-RT Is Dependent on Temperature-Regulated Expression of the Phage Host Receptor OmpF.

    Science.gov (United States)

    Leon-Velarde, Carlos G; Happonen, Lotta; Pajunen, Maria; Leskinen, Katarzyna; Kropinski, Andrew M; Mattinen, Laura; Rajtor, Monika; Zur, Joanna; Smith, Darren; Chen, Shu; Nawaz, Ayesha; Johnson, Roger P; Odumeru, Joseph A; Griffiths, Mansel W; Skurnik, Mikael

    2016-09-01

    Bacteriophages present huge potential both as a resource for developing novel tools for bacterial diagnostics and for use in phage therapy. This potential is also valid for bacteriophages specific for Yersinia enterocolitica To increase our knowledge of Y. enterocolitica-specific phages, we characterized two novel yersiniophages. The genomes of the bacteriophages vB_YenM_TG1 (TG1) and vB_YenM_ϕR1-RT (ϕR1-RT), isolated from pig manure in Canada and from sewage in Finland, consist of linear double-stranded DNA of 162,101 and 168,809 bp, respectively. Their genomes comprise 262 putative coding sequences and 4 tRNA genes and share 91% overall nucleotide identity. Based on phylogenetic analyses of their whole-genome sequences and large terminase subunit protein sequences, a genus named Tg1virus within the family Myoviridae is proposed, with TG1 and ϕR1-RT (R1RT in the ICTV database) as member species. These bacteriophages exhibit a host range restricted to Y. enterocolitica and display lytic activity against the epidemiologically significant serotypes O:3, O:5,27, and O:9 at and below 25°C. Adsorption analyses of lipopolysaccharide (LPS) and OmpF mutants demonstrate that these phages use both the LPS inner core heptosyl residues and the outer membrane protein OmpF as phage receptors. Based on RNA sequencing and quantitative proteomics, we also demonstrate that temperature-dependent infection is due to strong repression of OmpF at 37°C. In addition, ϕR1-RT was shown to be able to enter into a pseudolysogenic state. Together, this work provides further insight into phage-host cell interactions by highlighting the importance of understanding underlying factors which may affect the abundance of phage host receptors on the cell surface. Only a small number of bacteriophages infecting Y. enterocolitica, the predominant causative agent of yersiniosis, have been previously described. Here, two newly isolated Y. enterocolitica phages were studied in detail, with the aim of

  18. Shigella flexneri Infection in Caenorhabditis elegans: Cytopathological Examination and Identification of Host Responses

    Science.gov (United States)

    George, Divya T.; Behm, Carolyn A.; Hall, David H.; Mathesius, Ulrike; Rug, Melanie; Nguyen, Ken C. Q.; Verma, Naresh K.

    2014-01-01

    The Gram-negative bacterium Shigella flexneri is the causative agent of shigellosis, a diarrhoeal disease also known as bacillary dysentery. S. flexneri infects the colonic and rectal epithelia of its primate host and induces a cascade of inflammatory responses that culminates in the destruction of the host intestinal lining. Molecular characterization of host-pathogen interactions in this infection has been challenging due to the host specificity of S. flexneri strains, as it strictly infects humans and non-human primates. Recent studies have shown that S. flexneri infects the soil dwelling nematode Caenorhabditis elegans, however, the interactions between S. flexneri and C. elegans at the cellular level and the cause of nematode death are unknown. Here we attempt to gain insight into the complex host-pathogen interactions between S. flexneri and C. elegans. Using transmission electron microscopy, we show that live S. flexneri cells accumulate in the nematode intestinal lumen, produce outer membrane vesicles and invade nematode intestinal cells. Using two-dimensional differential in-gel electrophoresis we identified host proteins that are differentially expressed in response to S. flexneri infection. Four of the identified genes, aco-1, cct-2, daf-19 and hsp-60, were knocked down using RNAi and ACO-1, CCT-2 and DAF-19, which were identified as up-regulated in response to S. flexneri infection, were found to be involved in the infection process. aco-1 RNAi worms were more resistant to S. flexneri infection, suggesting S. flexneri-mediated disruption of host iron homeostasis. cct-2 and daf-19 RNAi worms were more susceptible to infection, suggesting that these genes are induced as a protective mechanism by C. elegans. These observations further our understanding of the processes involved in S. flexneri infection of C. elegans, which is immensely beneficial to the routine use of this new in vivo model to study S. flexneri pathogenesis. PMID:25187942

  19. Phylogeography and virulence structure of the powdery mildew population on its 'new' host triticale

    Directory of Open Access Journals (Sweden)

    Troch Veronique

    2012-06-01

    Full Text Available Abstract Background Powdery mildew, caused by the obligate biotrophic fungus Blumeria graminis, is a major problem in cereal production as it can reduce quality and yield. B. graminis has evolved eight distinct formae speciales (f.sp. which display strict host specialization. In the last decade, powdery mildew has emerged on triticale, the artificial intergeneric hybrid between wheat and rye. This emergence is probably triggered by a host range expansion of the wheat powdery mildew B. graminis f.sp. tritici. To gain more precise information about the evolutionary processes that led to this host range expansion, we pursued a combined pathological and genetic approach. Results B. graminis isolates were sampled from triticale, wheat and rye from different breeding regions in Europe. Pathogenicity tests showed that isolates collected from triticale are highly pathogenic on most of the tested triticale cultivars. Moreover, these isolates were also able to infect several wheat cultivars (their previous hosts, although a lower aggressiveness was observed compared to isolates collected from wheat. Phylogenetic analysis of nuclear gene regions identified two statistically significant clades, which to a certain extent correlated with pathogenicity. No differences in virulence profiles were found among the sampled regions, but the distribution of genetic variation demonstrated to be geography dependent. A multilocus haplotype network showed that haplotypes pathogenic on triticale are distributed at different sites in the network, but always clustered at or near the tips of the network. Conclusions This study reveals a genetic structure in B. graminis with population differentiation according to geography and host specificity. In addition, evidence is brought forward demonstrating that the host range expansion of wheat isolates to the new host triticale occurred recently and multiple times at different locations in Europe.

  20. Phylogeography and virulence structure of the powdery mildew population on its 'new' host triticale

    Science.gov (United States)

    2012-01-01

    Background Powdery mildew, caused by the obligate biotrophic fungus Blumeria graminis, is a major problem in cereal production as it can reduce quality and yield. B. graminis has evolved eight distinct formae speciales (f.sp.) which display strict host specialization. In the last decade, powdery mildew has emerged on triticale, the artificial intergeneric hybrid between wheat and rye. This emergence is probably triggered by a host range expansion of the wheat powdery mildew B. graminis f.sp. tritici. To gain more precise information about the evolutionary processes that led to this host range expansion, we pursued a combined pathological and genetic approach. Results B. graminis isolates were sampled from triticale, wheat and rye from different breeding regions in Europe. Pathogenicity tests showed that isolates collected from triticale are highly pathogenic on most of the tested triticale cultivars. Moreover, these isolates were also able to infect several wheat cultivars (their previous hosts), although a lower aggressiveness was observed compared to isolates collected from wheat. Phylogenetic analysis of nuclear gene regions identified two statistically significant clades, which to a certain extent correlated with pathogenicity. No differences in virulence profiles were found among the sampled regions, but the distribution of genetic variation demonstrated to be geography dependent. A multilocus haplotype network showed that haplotypes pathogenic on triticale are distributed at different sites in the network, but always clustered at or near the tips of the network. Conclusions This study reveals a genetic structure in B. graminis with population differentiation according to geography and host specificity. In addition, evidence is brought forward demonstrating that the host range expansion of wheat isolates to the new host triticale occurred recently and multiple times at different locations in Europe. PMID:22658131

  1. Shigella flexneri infection in Caenorhabditis elegans: cytopathological examination and identification of host responses.

    Directory of Open Access Journals (Sweden)

    Divya T George

    Full Text Available The Gram-negative bacterium Shigella flexneri is the causative agent of shigellosis, a diarrhoeal disease also known as bacillary dysentery. S. flexneri infects the colonic and rectal epithelia of its primate host and induces a cascade of inflammatory responses that culminates in the destruction of the host intestinal lining. Molecular characterization of host-pathogen interactions in this infection has been challenging due to the host specificity of S. flexneri strains, as it strictly infects humans and non-human primates. Recent studies have shown that S. flexneri infects the soil dwelling nematode Caenorhabditis elegans, however, the interactions between S. flexneri and C. elegans at the cellular level and the cause of nematode death are unknown. Here we attempt to gain insight into the complex host-pathogen interactions between S. flexneri and C. elegans. Using transmission electron microscopy, we show that live S. flexneri cells accumulate in the nematode intestinal lumen, produce outer membrane vesicles and invade nematode intestinal cells. Using two-dimensional differential in-gel electrophoresis we identified host proteins that are differentially expressed in response to S. flexneri infection. Four of the identified genes, aco-1, cct-2, daf-19 and hsp-60, were knocked down using RNAi and ACO-1, CCT-2 and DAF-19, which were identified as up-regulated in response to S. flexneri infection, were found to be involved in the infection process. aco-1 RNAi worms were more resistant to S. flexneri infection, suggesting S. flexneri-mediated disruption of host iron homeostasis. cct-2 and daf-19 RNAi worms were more susceptible to infection, suggesting that these genes are induced as a protective mechanism by C. elegans. These observations further our understanding of the processes involved in S. flexneri infection of C. elegans, which is immensely beneficial to the routine use of this new in vivo model to study S. flexneri pathogenesis.

  2. A Criterium for the Strict Positivity of the Density of the Law of a Poisson Process

    Directory of Open Access Journals (Sweden)

    Léandre Rémi

    2011-01-01

    Full Text Available We translate in semigroup theory our result (Léandre, 1990 giving a necessary condition so that the law of a Markov process with jumps could have a strictly positive density. This result express, that we have to jump in a finite number of jumps in a "submersive" way from the starting point to the end point if the density of the jump process is strictly positive in . We use the Malliavin Calculus of Bismut type of (Léandre, (2008;2010 translated in semi-group theory as a tool, and the interpretation in semi-group theory of some classical results of the stochastic analysis for Poisson process as, for instance, the formula giving the law of a compound Poisson process.

  3. The effect of 8 days of strict bed rest on the incretin effect in healthy volunteers

    DEFF Research Database (Denmark)

    Nielsen, Signe Tellerup; Harder-Lauridsen, Nina Majlund; Benatti, Fabiana Braga

    2016-01-01

    in the levels of GLP-1 and Glucagon. Bed rest led to a mean loss of 2.4 kg of fat-free mass, and induced insulin resistance evaluated by the Matsuda index, but did not affect the incretin effect (P = 0.6). In conclusion, 8 days of bed rest induces insulin resistance, but we did not see evidence of an associated......Bed rest and physical inactivity are the consequences of hospital admission for many patients. Physical inactivity induces changes in glucose metabolism, but its effect on the incretin effect, which is reduced in, e.g., Type 2 diabetes, is unknown. To investigate how 8 days of strict bed rest...... affects the incretin effect, 10 healthy nonobese male volunteers underwent 8 days of strict bed rest. Before and after the intervention, all volunteers underwent an oral glucose tolerance test (OGTT) followed by an intravenous glucose infusion (IVGI) on the following day to mimic the blood glucose profile...

  4. Detection of low numbers of microplastics in North Sea fish using strict quality assurance criteria.

    Science.gov (United States)

    Hermsen, Enya; Pompe, Renske; Besseling, Ellen; Koelmans, Albert A

    2017-09-15

    We investigated 400 individual fish of four North Sea species: Atlantic Herring, Sprat, Common Dab, and Whiting on ingestion of >20μm microplastic. Strict quality assurance criteria were followed in order to control contamination during the study. Two plastic particles were found in only 1 (a Sprat) out of 400 individuals (0.25%, with a 95% confidence interval of 0.09-1.1%). The particles were identified to consist of polymethylmethacrylate (PMMA) through FTIR spectroscopy. No contamination occurred during the study, showing the method applied to be suitable for microplastic ingestion studies in biota. We discuss the low particle count for North Sea fish with those in other studies and suggest a relation between reported particle count and degree of quality assurance applied. Microplastic ingestion by fish may be less common than thought initially, with low incidence shown in this study, and other studies adhering to strict quality assurance criteria. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. A strict anaerobic extreme thermophilic hydrogen-producing culture enriched from digested household waste

    DEFF Research Database (Denmark)

    Karakashev, Dimitar Borisov; Kotay, Shireen Meher; Trably, Eric

    2009-01-01

    sources. Growth on glucose produced acetate, H-2 and carbon dioxide. Maximal H-2 production rate on glucose was 1.1 mmol l(-1) h(-1) with a maximum H-2 yield of 1.9 mole H-2 per mole glucose. 16S ribosomal DNA clone library analyses showed that the culture members were phylogenetically affiliated......The aim of this study was to enrich, characterize and identify strict anaerobic extreme thermophilic hydrogen (H-2) producers from digested household solid wastes. A strict anaerobic extreme thermophilic H-2 producing bacterial culture was enriched from a lab-scale digester treating household...... wastes at 70 degrees C. The enriched mixed culture consisted of two rod-shaped bacterial members growing at an optimal temperature of 80 degrees C and an optimal pH 8.1. The culture was able to utilize glucose, galactose, mannose, xylose, arabinose, maltose, sucrose, pyruvate and glycerol as carbon...

  6. A Hybrid P2P Overlay Network for Non-strictly Hierarchically Categorized Content

    Science.gov (United States)

    Wan, Yi; Asaka, Takuya; Takahashi, Tatsuro

    In P2P content distribution systems, there are many cases in which the content can be classified into hierarchically organized categories. In this paper, we propose a hybrid overlay network design suitable for such content called Pastry/NSHCC (Pastry for Non-Strictly Hierarchically Categorized Content). The semantic information of classification hierarchies of the content can be utilized regardless of whether they are in a strict tree structure or not. By doing so, the search scope can be restrained to any granularity, and the number of query messages also decreases while maintaining keyword searching availability. Through simulation, we showed that the proposed method provides better performance and lower overhead than unstructured overlays exploiting the same semantic information.

  7. First report of Phoronis ovalis from Africa and its effect on mussel hosts

    African Journals Online (AJOL)

    Phoronis ovalis in Namibia leaves characteristic burrows in its hosts (0.2 mm diameter), primarily the native brown mussel Perna perna. In all, eight additional host species were identified, including one barnacle, four gastropods and three bivalves. The distribution of P. ovalis was strictly subtidal, where it reached 99% ...

  8. In vitro host erythrocyte specificity and differential morphology of Babesia divergens and a zoonotic Babesia sp. from eastern cottontail rabbits (Sylvilagus floridanus).

    Science.gov (United States)

    Spencer, Angela M; Goethert, Heidi K; Telford, Samuel R; Holman, Patricia J

    2006-04-01

    A Babesia sp. isolated from eastern cottontail rabbits (Sylvilagus floridanus) is morphologically similar and genetically identical, based on SSU rRNA gene comparisons, to 2 agents responsible for human babesiosis in the United States. This zoonotic agent is closely related to the European parasite, Babesia divergens. The 2 organisms were characterized by in vitro comparisons. In vitro growth of the rabbit Babesia sp. was supported in human and cottontail rabbit erythrocytes, but not in bovine cells. Babesia divergens was supported in vitro in bovine and human erythrocytes, but not in cottontail rabbit cells. Morphometric analysis classifies B. divergens as a small babesia in bovine erythrocytes, but the parasite exceeds this size in human erythrocytes. The rabbit Babesia sp. is large, the same size in both human or rabbit erythrocytes, and is significantly larger than B. divergens. Eight or more rabbit Babesia sp. parasites may occur within a single erythrocyte, sometimes in a floret array, unlike B. divergens. The erythrocyte specificity and morphological differences reported in this study agree with previous in vivo results and validate the use of in vitro methods for characterization of Babesia species.

  9. Weak asymptotic solution for a non-strictly hyperbolic system of conservation laws-II

    Directory of Open Access Journals (Sweden)

    Manas Ranjan Sahoo

    2016-04-01

    Full Text Available In this article we introduce a concept of entropy weak asymptotic solution for a system of conservation laws and construct the same for a prolonged system of conservation laws which is highly non-strictly hyperbolic. This is first done for Riemann type initial data by introducing $\\delta,\\delta',\\delta''$ waves along a discontinuity curve and then for general initial data by piecing together the Riemann solutions.

  10. Multiple-Set Split Feasibility Problems for κ-Strictly Pseudononspreading Mapping in Hilbert Spaces

    Directory of Open Access Journals (Sweden)

    Jing Quan

    2013-01-01

    Full Text Available The purpose of this paper is to prove some weak and strong convergence theorems for solving the multiple-set split feasibility problems for κ-strictly pseudononspreading mapping in infinite-dimensional Hilbert spaces by using the proposed iterative method. The main results presented in this paper extend and improve the corresponding results of Xu et al. (2006, of Osilike et al. (2011, and of many other authors.

  11. Multiobjective Optimization for the Forecasting Models on the Base of the Strictly Binary Trees

    OpenAIRE

    Nadezhda Astakhova; Liliya Demidova; Evgeny Nikulchev

    2016-01-01

    The optimization problem dealing with the development of the forecasting models on the base of strictly binary trees has been considered. The aim of paper is the comparative analysis of two optimization variants which are applied for the development of the forecasting models. Herewith the first optimization variant assumes the application of one quality indicator of the forecasting model named as the affinity indicator and the second variant realizes the application of two quality indicators ...

  12. Cannabis legalization with strict regulation, the overall superior policy option for public health.

    Science.gov (United States)

    Rehm, J; Fischer, B

    2015-06-01

    Cannabis is the most prevalently used drug globally, with many jurisdictions considering varying reform options to current policies to deal with this substance and associated harm. Three policy options are available: prohibition, decriminalization, and legalization, with prohibition currently the dominant model globally. This contribution gives reasons why legalization with strict regulation should be considered superior to other options with respect to public health in high income countries in North America. © 2015 ASCPT.

  13. Examination of the PCICE method in the nearly incompressible, as well as strictly incompressible, limits

    International Nuclear Information System (INIS)

    Berry, Ray A.; Martineau, Richard C.

    2007-01-01

    The conservative-form, pressure-based PCICE numerical method (Martineau and Berry, 2004) (Berry, 2006), recently developed for computing transient fluid flows of all speeds from very low to very high (with strong shocks), is simplified and generalized. Though the method automatically treats a continuous transition of compressibility, three distinct, limiting compressibility regimes are formally defined for purposes of discussion and comparison with traditional methods - the strictly incompressible limit, the nearly incompressible limit, and the fully compressible limit. The PCICE method's behavior is examined in each limiting regime. In the strictly incompressible limit the PCICE algorithm reduces to the traditional MAC-type method with velocity divergence driving the pressure Poisson equation. In the nearly incompressible limit the PCICE algorithm is found to reduce to a generalization of traditional incompressible methods, i.e. to one in which not only the velocity divergence effect, but also the density gradient effect is included as a driving function in the pressure Poisson equation. This nearly incompressible regime has received little attention, and it appears that in the past, strictly incompressible methods may have been conveniently applied to flows in this regime at the expense of ignoring a potentially important coupling mechanism. This could be significant in many important flows; for example, in natural convection flows resulting from high heat flux. In the fully compressible limit or regime, the algorithm is found to reduce to an expression equivalent to density-based methods for high-speed flow. (author)

  14. Frequency effect on p-nitrophenol degradation under conditions of strict acoustic and electric control

    Directory of Open Access Journals (Sweden)

    Chang-ping Zhu

    2011-03-01

    Full Text Available The process of decomposing p-nitrophenol (PNP with power ultrasound requires strict control of acoustic and electric conditions. In this study, the conditions, including acoustic power and acoustic intensity, but not ultrasonic frequency, were controlled strictly at constant levels. The absorbency and the COD concentrations of the samples were measured in order to show the variation of the sample concentration. The results show significant differences in the trend of the solution degradation rate as acoustic power increases after the PNP solution (with a concentration of 114 mg/L and a pH value of 5.4 is irradiated for 60 min with ultrasonic frequencies of 530.8 kHz, 610.6 kHz, 855.0 kHz, and 1 130.0 kHz. The degradation rate of the solution increases with time and acoustic power (acoustic intensity. On the other hand, the degradation rate of the solution is distinctly dependent on frequency when the acoustic power and intensity are strictly controlled and maintained at constant levels. The degradation rate of the PNP solution declines with ultrasonic frequencies of 530.8 kHz, 610.6 kHz, 855.0 kHz, and 1 130.0 kHz; the COD concentration, on the contrary, increase.

  15. TESTING STRICT HYDROSTATIC EQUILIBRIUM IN SIMULATED CLUSTERS OF GALAXIES: IMPLICATIONS FOR A1689

    International Nuclear Information System (INIS)

    Molnar, S. M.; Umetsu, K.; Chiu, I.-N.; Chen, P.; Hearn, N.; Broadhurst, T.; Bryan, G.; Shang, C.

    2010-01-01

    Accurate mass determination of clusters of galaxies is crucial if they are to be used as cosmological probes. However, there are some discrepancies between cluster masses determined based on gravitational lensing and X-ray observations assuming strict hydrostatic equilibrium (i.e., the equilibrium gas pressure is provided entirely by thermal pressure). Cosmological simulations suggest that turbulent gas motions remaining from hierarchical structure formation may provide a significant contribution to the equilibrium pressure in clusters. We analyze a sample of massive clusters of galaxies drawn from high-resolution cosmological simulations and find a significant contribution (20%-45%) from non-thermal pressure near the center of relaxed clusters, and, in accord with previous studies, a minimum contribution at about 0.1 R vir , growing to about 30%-45% at the virial radius, R vir . Our results strongly suggest that relaxed clusters should have significant non-thermal support in their core region. As an example, we test the validity of strict hydrostatic equilibrium in the well-studied massive galaxy cluster A1689 using the latest high-resolution gravitational lensing and X-ray observations. We find a contribution of about 40% from non-thermal pressure within the core region of A1689, suggesting an alternate explanation for the mass discrepancy: the strict hydrostatic equilibrium is not valid in this region.

  16. Temporary Strict Maternal Avoidance of Cow’s Milk and Infantile Colic

    Directory of Open Access Journals (Sweden)

    Firoozeh Sajedi

    2009-12-01

    Full Text Available Infant colic is a common problem characterized by excessive crying and fussing. We examined whether colic symptoms of exclusively breast-milk-fed infants would be improved by temporary strict maternal avoidance of cows milk. This study is analytic and experimental. Sixty-six subjects were recruited during winter of 2006 from a clinic in Isfahan, Iran. Breast-milk-fed in-fants with "colic", age 3-6 months and to be in otherwise good health were referred by pediatri-cians. The intervention was 1 week period of strict maternal avoidance of cows milk while they continued exclusive breast-milk-feeding. All infants showed improvement in distressed behavior (crying and fussing during intervention. The total recorded crying and fussing time was reduced by an average of 31%. A significant difference was found in cry and fuss time between first and last 2 days of intervention (P = 0.000. Cows milk proteins may play an etiologic role in colic. We propose that a brief intervention with strict maternal avoidance of cows milk may be an effective treatment for colic in some breast-milk-fed infants.

  17. Host-Specific Patterns of Genetic Diversity among IncI1-Iγ and IncK Plasmids Encoding CMY-2 β-Lactamase in Escherichia coli Isolates from Humans, Poultry Meat, Poultry, and Dogs in Denmark.

    Science.gov (United States)

    Hansen, Katrine Hartung; Bortolaia, Valeria; Nielsen, Christine Ahl; Nielsen, Jesper Boye; Schønning, Kristian; Agersø, Yvonne; Guardabassi, Luca

    2016-08-01

    CMY-2 is the most common plasmid-mediated AmpC β-lactamase in Escherichia coli isolates of human and animal origin. The aim of this study was to elucidate the epidemiology of CMY-2-producing E. coli in Denmark. Strain and plasmid relatedness was studied in 93 CMY-2-producing clinical and commensal E. coli isolates collected from 2006 to 2012 from humans, retail poultry meat, broilers, and dogs. Multilocus sequence typing (MLST), antimicrobial susceptibility testing, and conjugation were performed in conjunction with plasmid replicon typing, plasmid multilocus sequence typing (pMLST), restriction fragment length polymorphism (RFLP), and sequencing of selected blaCMY-2-harboring plasmids. MLST revealed high strain diversity, with few E. coli lineages occurring in multiple host species and sample types. blaCMY-2 was detected on plasmids in 83 (89%) isolates. Most (75%) of the plasmids were conjugative and did not (96%) cotransfer resistance to antimicrobials other than cephalosporins. The main replicon types identified were IncI1-Iγ (55%) and IncK (39%). Isolates from different host species mainly carried distinct plasmid subtypes. Seven of the 18 human isolates harbored IncI1-Iγ/sequence type 2 (ST2), IncI1-Iγ/ST12, or IncK plasmids highly similar to those found among animal isolates, even though highly related human and animal plasmids differed by nonsynonymous single nucleotide polymorphisms (SNPs) or insertion sequence elements. This study clearly demonstrates that the epidemiology of CMY-2 can be understood only by thorough plasmid characterization. To date, the spread of this β-lactam resistance determinant in Denmark is mainly associated with IncK and IncI1-Iγ plasmids that are generally distributed according to host-specific patterns. These baseline data will be useful to assess the consequences of the increasing human exposure to CMY-2-producing E. coli via animal sources. CMY-2 is the most common plasmid-mediated AmpC β-lactamase in Escherichia coli

  18. Rate Control Efficacy in Permanent Atrial Fibrillation : Successful and Failed Strict Rate Control Against a Background of Lenient Rate Control

    NARCIS (Netherlands)

    Groenveld, Hessel F.; Tijssen, Jan G. P.; Crijns, Harry J. G. M.; Van den Berg, Maarten P.; Hillege, Hans L.; Alings, Marco; Van Veldhuisen, Dirk J.; Van Gelder, Isabelle C.

    2013-01-01

    Objectives This study sought to investigate differences in outcome between patients treated with successful strict, failed strict, and lenient rate control. Background The RACE II (Rate Control Efficacy in Permanent Atrial Fibrillation) study showed no difference in outcome between lenient and

  19. Strict versus liberal insulin therapy in the cardiac surgery patient: An evidence-based practice development, implementation and evaluation project.

    Science.gov (United States)

    Gordon, Jacqueline M; Lauver, Lori S; Buck, Harleah G

    2018-02-01

    Hyperglycemia post-cardiac surgery is associated with poor clinical outcomes. Recent studies suggest maintaining liberal glycemic control (liberal CII protocol. Retrospective review of 144 strict CII patient records and 147 liberal CII patient records. Mean blood glucose was 159.8mg/dL (liberal CII) compared to 143.3mg/dL (strict CII) (p≤0.001). No surgical site infections occurred in either group. Mean ICU length of stay was 4.5days (liberal) versus 4.4days (strict) (p=0.74). Two 30-day mortalities occurred for the liberal cohort compared to no deaths in the strict group (p=0.49). Hypoglycemia incidence within 24h after surgery was 0.1% (liberal) compared to 0.3% (strict) compared to (p=0.16). Use of a nurse managed liberal CII resulted in similar outcomes with fewer incidents of hypoglycemia. Copyright © 2017. Published by Elsevier Inc.

  20. Eimeria tenella: host specificity in gallinaceous birds.

    Science.gov (United States)

    Vetterling, J M

    1976-02-01

    Eight species representing 8 genera of gallinaceous birds were used: Alectoris graeca; Colinus virginianus; Coturnix coturnix; Gallus gallus; Meleagris gallopavo; Numidia meleagris; Pavo cristatus; Phasianus colchicus. Three week-old birds were dosed with sporulated oocysts of Eimeria tenella Beltsville strain. At 4, 24, 48, 72, 96, 120 and 144, and 168 hr after inoculation, 1-3 infected birds and uninoculated controls of each species were killed by cardiac exsanguination. Pieces of intestines were fixed and examined for stages of E. tenella as stained paraffin sections or indirect fluorescent antibody preparations. Oocyst counts were made in droppings collected for the first 6 days of the patent period. Sporozoites were found in the lamina propria of some birds of 5 species at 4 hr postinoculation, but no stages were found thereafter except in the breeds of G. gallus and A. gracea. At 144 and 168 hr postinoculation, a few macrogametes were found in the ceca of 2 A. gracea, but no oocysts were found in the feces. No statistical difference was found between the number of oocysts produced/bird in the breeds of G. gallus examined. It is evident from these observations the E. tenella did not complete its life cycle in several close phylogenetic relatives of G. gallus, even though in other studies this parasite was found to complete its life cycle in cell cultures derived from the same birds.

  1. Effects of growth temperature and strictly anaerobic recovery on the survival of Listeria monocytogenes during pasteurization.

    Science.gov (United States)

    Knabel, S J; Walker, H W; Hartman, P A; Mendonca, A F

    1990-02-01

    Listeria monocytogenes F5069 was suspended in either Trypticase soy broth-0.6% yeast extract (TSBYE) or sterile, whole milk and heated at 62.8 degrees C in sealed thermal death time tubes. Severely heat-injured cells were recovered in TSBYE within sealed thermal death time tubes because of the formation of reduced conditions in the depths of the TSBYE. Also, the use of strictly anaerobic Hungate techniques significantly increased recovery in TSBYE containing 1.5% agar compared with aerobically incubated controls. The exogenous addition of catalase, but not superoxide dismutase, slightly increased the recovery of heat-injured cells in TSBYE containing 1.5% agar incubated aerobically. Growth of cells at 43 degrees C caused a greater increase in heat resistance as compared with cells heat shocked at 43 degrees C or cells grown at lower temperatures. Growth of L. monocytogenes at 43 degrees C and enumeration by the use of strictly anaerobic Hungate techniques resulted in D62.8 degrees C values that were at least sixfold greater than those previously obtained by using cells grown at 37 degrees C and aerobic plating. Results indicate that, under the conditions of the present study, high levels of L. monocytogenes would survive the minimum low-temperature, long-time treatment required by the U.S. Food and Drug Administration for pasteurizing milk. The possible survival of low levels of L. monocytogenes during high-temperature, short-time pasteurization and enumeration of injured cells by recovery on selective media under strictly anaerobic conditions are discussed.

  2. RelTime Rates Collapse to a Strict Clock When Estimating the Timeline of Animal Diversification.

    Science.gov (United States)

    Lozano-Fernandez, Jesus; Dos Reis, Mario; Donoghue, Philip C J; Pisani, Davide

    2017-05-01

    Establishing an accurate timescale for the history of life is crucial to understand evolutionary processes. For this purpose, relaxed molecular clock models implemented in a Bayesian MCMC framework are generally used. However, these methods are time consuming. RelTime, a non-Bayesian method implementing a fast, ad hoc, algorithm for relative dating, was developed to overcome the computational inefficiencies of Bayesian software. RelTime was recently used to investigate the timing of origin of animals, yielding results consistent with early strict clock studies from the 1980s and 1990s, estimating metazoans to have a Mesoproterozoic origin-over a billion years ago. RelTime results are unexpected and disagree with the largest majority of modern, relaxed, Bayesian molecular clock analyses, which suggest animals originated in the Tonian-Cryogenian (less that 850 million years ago). Here, we demonstrate that RelTime-inferred divergence times for the origin of animals are spurious, a consequence of the inability of RelTime to relax the clock along the internal branches of the animal phylogeny. RelTime-inferred divergence times are comparable to strict-clock estimates because they are essentially inferred under a strict clock. Our results warn us of the danger of using ad hoc algorithms making implicit assumptions about rate changes along a tree. Our study roundly rejects a Mesoproterozoic origin of animals; metazoans emerged in the Tonian-Cryogenian, and diversified in the Ediacaran, in the immediate prelude to the routine fossilization of animals in the Cambrian associated with the emergence of readily preserved skeletons. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  3. Effects of growth temperature and strictly anaerobic recovery on the survival of Listeria monocytogenes during pasteurization.

    OpenAIRE

    Knabel, S J; Walker, H W; Hartman, P A; Mendonca, A F

    1990-01-01

    Listeria monocytogenes F5069 was suspended in either Trypticase soy broth-0.6% yeast extract (TSBYE) or sterile, whole milk and heated at 62.8 degrees C in sealed thermal death time tubes. Severely heat-injured cells were recovered in TSBYE within sealed thermal death time tubes because of the formation of reduced conditions in the depths of the TSBYE. Also, the use of strictly anaerobic Hungate techniques significantly increased recovery in TSBYE containing 1.5% agar compared with aerobicall...

  4. The Dirichlet problem for the Monge-Ampere equation in convex (but not strictly convex domains

    Directory of Open Access Journals (Sweden)

    David Hartenstine

    2006-10-01

    Full Text Available It is well-known that the Dirichlet problem for the Monge-Amp`ere equation $det D^2 u = mu$ in a bounded strictly convex domain $Omega$ in $mathbb{R}^n$ has a weak solution (in the sense of Aleksandrov for any finite Borel measure $mu$ on $Omega$ and for any continuous boundary data. We consider the Dirichlet problem when $Omega$ is only assumed to be convex, and give a necessary and sufficient condition on the boundary data for solvability.

  5. Selections of the metric projection operator and strict solarity of sets with continuous metric projection

    Science.gov (United States)

    Alimov, A. R.

    2017-07-01

    In a broad class of finite-dimensional Banach spaces, we show that a closed set with lower semicontinuous metric projection is a strict sun, admits a continuous selection of the metric projection operator onto it, has contractible intersections with balls, and its (nonempty) intersection with any closed ball is a retract of this ball. For sets with continuous metric projection, a number of new results relating the solarity of such sets to the stability of the operator of best approximation are obtained. Bibliography 25 titles.

  6. Transplanting Diseases from Organ Donors in Western Europe: Fault Liability or Strict Liability?

    Science.gov (United States)

    Broeckx, Nils; Verhoeven, Dimitri

    2015-06-01

    This article will examine the problem of disease transmission through organ transplantation from a civil liability perspective. Both fault liability and strict product liability might be possible. These two types of liability will be compared, while applying them to the actions of the central parties involved in organ donation and transplantation, namely the physician/hospital, the donor and the organ exchange organisation. While product liability is generally an easier way to obtain compensation than fault liability, it might nevertheless place too heavy a burden on the transplant professionals.

  7. Single molecule experiments challenge the strict wave-particle dualism of light.

    Science.gov (United States)

    Greulich, Karl Otto

    2010-01-21

    Single molecule techniques improve our understanding of the photon and light. If the single photon double slit experiment is performed at the "single photon limit" of a multi-atom light source, faint light pulses with more than one photon hamper the interpretation. Single molecules, quantum dots or defect centres in crystals should be used as light source. "Single photon detectors" do not meet their promise-only "photon number resolving single photon detectors" do so. Particularly, the accumulation time argument, the only safe basis for the postulate of a strictly particle like photon, has so far not yet been verified.

  8. Single Molecule Experiments Challenge the Strict Wave-Particle Dualism of Light

    Directory of Open Access Journals (Sweden)

    Karl Otto Greulich

    2010-01-01

    Full Text Available Single molecule techniques improve our understanding of the photon and light. If the single photon double slit experiment is performed at the “single photon limit” of a multi-atom light source, faint light pulses with more than one photon hamper the interpretation. Single molecules, quantum dots or defect centres in crystals should be used as light source. “Single photon detectors” do not meet their promise―only “photon number resolving single photon detectors” do so. Particularly, the accumulation time argument, the only safe basis for the postulate of a strictly particle like photon, has so far not yet been verified.

  9. Vaccination with an Attenuated Mutant of Ehrlichia chaffeensis Induces Pathogen-Specific CD4+ T Cell Immunity and Protection from Tick-Transmitted Wild-Type Challenge in the Canine Host.

    Directory of Open Access Journals (Sweden)

    Jodi L McGill

    Full Text Available Ehrlichia chaffeensis is a tick-borne rickettsial pathogen and the causative agent of human monocytic ehrlichiosis. Transmitted by the Amblyomma americanum tick, E. chaffeensis also causes disease in several other vertebrate species including white-tailed deer and dogs. We have recently described the generation of an attenuated mutant strain of E. chaffeensis, with a mutation in the Ech_0660 gene, which is able to confer protection from secondary, intravenous-administered, wild-type E. chaffeensis infection in dogs. Here, we extend our previous results, demonstrating that vaccination with the Ech_0660 mutant protects dogs from physiologic, tick-transmitted, secondary challenge with wild-type E. chaffeensis; and describing, for the first time, the cellular and humoral immune responses induced by Ech_0660 mutant vaccination and wild-type E. chaffeensis infection in the canine host. Both vaccination and infection induced a rise in E. chaffeensis-specific antibody titers and a significant Th1 response in peripheral blood as measured by E. chaffeensis antigen-dependent CD4+ T cell proliferation and IFNγ production. Further, we describe for the first time significant IL-17 production by peripheral blood leukocytes from both Ech_0660 mutant vaccinated animals and control animals infected with wild-type E. chaffeensis, suggesting a previously unrecognized role for IL-17 and Th17 cells in the immune response to rickettsial pathogens. Our results are a critical first step towards defining the role of the immune system in vaccine-induced protection from E. chaffeensis infection in an incidental host; and confirm the potential of the attenuated mutant clone, Ech_0660, to be used as a vaccine candidate for protection against tick-transmitted E. chaffeensis infection.

  10. Vaccination with an Attenuated Mutant of Ehrlichia chaffeensis Induces Pathogen-Specific CD4+ T Cell Immunity and Protection from Tick-Transmitted Wild-Type Challenge in the Canine Host.

    Science.gov (United States)

    McGill, Jodi L; Nair, Arathy D S; Cheng, Chuanmin; Rusk, Rachel A; Jaworski, Deborah C; Ganta, Roman R

    2016-01-01

    Ehrlichia chaffeensis is a tick-borne rickettsial pathogen and the causative agent of human monocytic ehrlichiosis. Transmitted by the Amblyomma americanum tick, E. chaffeensis also causes disease in several other vertebrate species including white-tailed deer and dogs. We have recently described the generation of an attenuated mutant strain of E. chaffeensis, with a mutation in the Ech_0660 gene, which is able to confer protection from secondary, intravenous-administered, wild-type E. chaffeensis infection in dogs. Here, we extend our previous results, demonstrating that vaccination with the Ech_0660 mutant protects dogs from physiologic, tick-transmitted, secondary challenge with wild-type E. chaffeensis; and describing, for the first time, the cellular and humoral immune responses induced by Ech_0660 mutant vaccination and wild-type E. chaffeensis infection in the canine host. Both vaccination and infection induced a rise in E. chaffeensis-specific antibody titers and a significant Th1 response in peripheral blood as measured by E. chaffeensis antigen-dependent CD4+ T cell proliferation and IFNγ production. Further, we describe for the first time significant IL-17 production by peripheral blood leukocytes from both Ech_0660 mutant vaccinated animals and control animals infected with wild-type E. chaffeensis, suggesting a previously unrecognized role for IL-17 and Th17 cells in the immune response to rickettsial pathogens. Our results are a critical first step towards defining the role of the immune system in vaccine-induced protection from E. chaffeensis infection in an incidental host; and confirm the potential of the attenuated mutant clone, Ech_0660, to be used as a vaccine candidate for protection against tick-transmitted E. chaffeensis infection.

  11. Host-Directed Therapies for Tuberculosis.

    Science.gov (United States)

    Tobin, David M

    2015-05-18

    Host-directed therapies are a relatively new and promising approach to treatment of tuberculosis. Modulation of specific host immune pathways, including those that impact inflammation and immunopathology, can limit mycobacterial infection and pathology, both in cell culture and in animal models. This review explores a range of host pathways and drugs, some already approved for clinical use that have the potential to provide new adjunctive therapies for tuberculosis. Drugs targeting host processes may largely avoid the development of bacterial antibiotic resistance, a major public health concern for tuberculosis. However, these drugs may also have generally increased risk for side effects on the host. Understanding the specific mechanisms by which these drugs act and the relationship of these mechanisms to Mycobacterium tuberculosis pathogenesis will be critical in selecting appropriate host-directed therapy. Overall, these host-directed compounds provide a novel strategy for antituberculosis therapy. Copyright © 2015 Cold Spring Harbor Laboratory Press; all rights reserved.

  12. Fuzzy Adaptive Decentralized Optimal Control for Strict Feedback Nonlinear Large-Scale Systems.

    Science.gov (United States)

    Sun, Kangkang; Sui, Shuai; Tong, Shaocheng

    2018-04-01

    This paper considers the optimal decentralized fuzzy adaptive control design problem for a class of interconnected large-scale nonlinear systems in strict feedback form and with unknown nonlinear functions. The fuzzy logic systems are introduced to learn the unknown dynamics and cost functions, respectively, and a state estimator is developed. By applying the state estimator and the backstepping recursive design algorithm, a decentralized feedforward controller is established. By using the backstepping decentralized feedforward control scheme, the considered interconnected large-scale nonlinear system in strict feedback form is changed into an equivalent affine large-scale nonlinear system. Subsequently, an optimal decentralized fuzzy adaptive control scheme is constructed. The whole optimal decentralized fuzzy adaptive controller is composed of a decentralized feedforward control and an optimal decentralized control. It is proved that the developed optimal decentralized controller can ensure that all the variables of the control system are uniformly ultimately bounded, and the cost functions are the smallest. Two simulation examples are provided to illustrate the validity of the developed optimal decentralized fuzzy adaptive control scheme.

  13. Host-to-host variation of ecological interactions in polymicrobial infections.

    Science.gov (United States)

    Mukherjee, Sayak; Weimer, Kristin E; Seok, Sang-Cheol; Ray, Will C; Jayaprakash, C; Vieland, Veronica J; Swords, W Edward; Das, Jayajit

    2014-12-04

    Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host-microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of differences between hosts. Here, we analyze mechanisms underlying host-to-host variations of bacterial infection kinetics, using the well characterized experimental infection model of polymicrobial otitis media (OM) in chinchillas, in combination with population dynamic models and a maximum entropy (MaxEnt) based inference scheme. We find that the nature of the interactions between bacterial species critically regulates host-to-host variations in these interactions. Surprisingly, seemingly unrelated phenomena, such as the efficiency of individual bacterial species in utilizing nutrients for growth, and the microbe-specific host immune response, can become interdependent in a host population. The latter finding suggests a potential mechanism that could lead to selection of specific strains of bacterial species during the coevolution of the host immune response and the bacterial species.

  14. Host-to-host variation of ecological interactions in polymicrobial infections

    Science.gov (United States)

    Mukherjee, Sayak; Weimer, Kristin E.; Seok, Sang-Cheol; Ray, Will C.; Jayaprakash, C.; Vieland, Veronica J.; Swords, W. Edward; Das, Jayajit

    2015-02-01

    Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host-microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of differences between hosts. Here, we analyze mechanisms underlying host-to-host variations of bacterial infection kinetics, using the well characterized experimental infection model of polymicrobial otitis media (OM) in chinchillas, in combination with population dynamic models and a maximum entropy (MaxEnt) based inference scheme. We find that the nature of the interactions between bacterial species critically regulates host-to-host variations in these interactions. Surprisingly, seemingly unrelated phenomena, such as the efficiency of individual bacterial species in utilizing nutrients for growth, and the microbe-specific host immune response, can become interdependent in a host population. The latter finding suggests a potential mechanism that could lead to selection of specific strains of bacterial species during the coevolution of the host immune response and the bacterial species.

  15. New host and the extend of the host range of warble fly Hypoderma diana (Diptera, Hypodermatidae

    Directory of Open Access Journals (Sweden)

    Pavlásek Ivan

    2014-03-01

    Full Text Available Warble fly Hypoderma diana is known to be a parasite not only of roe deer and other species of Cervidae but also of non-specific hosts from among other orders of ungulates. First-instar larvae of Hypoderma diana, a specific parasite of Cervidae, have been found in a new non-specific host, i.e. the wild boar (Sus scrofa. This finding is further evidence of the exceptional adaptability of this species of subcutaneous warble fly of the family Hypodermatidae. It corroborates the validity of the proposition that the host range of a host-specific parasite can only be ext

  16. Study on Environment Performance Evaluation and Regional Differences of Strictly-Environmental-Monitored Cities in China

    Directory of Open Access Journals (Sweden)

    Ji Guo

    2017-12-01

    Full Text Available With the rapid economic growth and development, the problem of environmental pollution in China’s cities is becoming increasingly serious, and environmental pollution takes on a regional difference. There is, however, little comprehensive evaluation on the environmental performance and the regional difference of strictly-environmental-monitored cities in China. In this paper, the environmental performance of 109 strictly-environmental-monitored cities in China is evaluated in terms of natural performance, management performance, and scale performance by Data Envelopment Analysis (DEA, incorporating PM2.5 and PM10 as undesirable outputs. The empirical results show that: (1 At present, the natural performance is quite high, while the management performance is noticeably low for most cities. (2 The gap between the level of economic development and environmental protection among cities in China is large, and the scale efficiency of big cities is better than that of smaller cities. The efficiency value of large-scale cities such as Beijing, Shanghai, Guangzhou, Shenzhen, etc. is high, equaling 1; the value of smaller cities such as Sanmenxia, Baoding, Mudanjiang, and Pingdingshan is low, close to 0, indicating that big cities are characterized by high environmental efficiency. (3 From the perspective of region, the level of environmental performance in China is very uneven. For example, the environmental efficiency level of the Pan-Pearl River Delta region is superior to that of the Pan-Yangtze River region and the Bahia Rim region, whose values of environmental efficiency are 0.858, 0.658, and 0.622 respectively. The average efficiency of the Southern Coastal Economic Zone, Eastern Coastal Comprehensive Economic Zone, and the Comprehensive Economic Zone in the middle reaches of the Yangtze River is higher than that of other regions. Finally, corresponding countermeasures and suggestions are put forward. The method used in this paper is applicable

  17. Disordered strictly jammed binary sphere packings attain an anomalously large range of densities

    Science.gov (United States)

    Hopkins, Adam B.; Stillinger, Frank H.; Torquato, Salvatore

    2013-08-01

    Previous attempts to simulate disordered binary sphere packings have been limited in producing mechanically stable, isostatic packings across a broad spectrum of packing fractions. Here we report that disordered strictly jammed binary packings (packings that remain mechanically stable under general shear deformations and compressions) can be produced with an anomalously large range of average packing fractions 0.634≤ϕ≤0.829 for small to large sphere radius ratios α restricted to α≥0.100. Surprisingly, this range of average packing fractions is obtained for packings containing a subset of spheres (called the backbone) that are exactly strictly jammed, exactly isostatic, and also generated from random initial conditions. Additionally, the average packing fractions of these packings at certain α and small sphere relative number concentrations x approach those of the corresponding densest known ordered packings. These findings suggest for entropic reasons that these high-density disordered packings should be good glass formers and that they may be easy to prepare experimentally. We also identify an unusual feature of the packing fraction of jammed backbones (packings with rattlers excluded). The backbone packing fraction is about 0.624 over the majority of the α-x plane, even when large numbers of small spheres are present in the backbone. Over the (relatively small) area of the α-x plane where the backbone is not roughly constant, we find that backbone packing fractions range from about 0.606 to 0.829, with the volume of rattler spheres comprising between 1.6% and 26.9% of total sphere volume. To generate isostatic strictly jammed packings, we use an implementation of the Torquato-Jiao sequential linear programming algorithm [Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.82.061302 82, 061302 (2010)], which is an efficient producer of inherent structures (mechanically stable configurations at the local maxima in the density landscape). The identification and

  18. Disordered strictly jammed binary sphere packings attain an anomalously large range of densities.

    Science.gov (United States)

    Hopkins, Adam B; Stillinger, Frank H; Torquato, Salvatore

    2013-08-01

    Previous attempts to simulate disordered binary sphere packings have been limited in producing mechanically stable, isostatic packings across a broad spectrum of packing fractions. Here we report that disordered strictly jammed binary packings (packings that remain mechanically stable under general shear deformations and compressions) can be produced with an anomalously large range of average packing fractions 0.634≤φ≤0.829 for small to large sphere radius ratios α restricted to α≥0.100. Surprisingly, this range of average packing fractions is obtained for packings containing a subset of spheres (called the backbone) that are exactly strictly jammed, exactly isostatic, and also generated from random initial conditions. Additionally, the average packing fractions of these packings at certain α and small sphere relative number concentrations x approach those of the corresponding densest known ordered packings. These findings suggest for entropic reasons that these high-density disordered packings should be good glass formers and that they may be easy to prepare experimentally. We also identify an unusual feature of the packing fraction of jammed backbones (packings with rattlers excluded). The backbone packing fraction is about 0.624 over the majority of the α-x plane, even when large numbers of small spheres are present in the backbone. Over the (relatively small) area of the α-x plane where the backbone is not roughly constant, we find that backbone packing fractions range from about 0.606 to 0.829, with the volume of rattler spheres comprising between 1.6% and 26.9% of total sphere volume. To generate isostatic strictly jammed packings, we use an implementation of the Torquato-Jiao sequential linear programming algorithm [Phys. Rev. E 82, 061302 (2010)], which is an efficient producer of inherent structures (mechanically stable configurations at the local maxima in the density landscape). The identification and explicit construction of binary packings

  19. Lyme Neuroborreliosis: Preliminary Results from an Urban Referral Center Employing Strict CDC Criteria for Case Selection

    Directory of Open Access Journals (Sweden)

    David S. Younger

    2010-01-01

    Full Text Available Lyme neuroborreliosis or “neurological Lyme disease” was evidenced in 2 of 23 patients submitted to strict criteria for case selection of the Centers for Disease Control and Prevention employing a two-tier test to detect antibodies to Borrelia burgdorferi at a single institution. One patient had symptomatic polyradiculoneuritis, dysautonomia, and serological evidence of early infection; and another had symptomatic small fiber sensory neuropathy, distal polyneuropathy, dysautonomia, and serological evidence of late infection. In the remaining patients symptoms initially ascribed to Lyme disease were probably unrelated to B. burgdorferi infection. Our findings suggest early susceptibility and protracted involvement of the nervous system most likely due to the immunological effects of B. burgdorferi infection, although the exact mechanisms remain uncertain.

  20. On The Integral Representation of Strictly Continuous Set-Valued Maps

    Directory of Open Access Journals (Sweden)

    Anaté K. Lakmon

    2015-11-01

    Full Text Available Let T be a completely regular topological space and C(T be the space of bounded, continuous real-valued functions on T. C(T is endowed with the strict topology (the topology generated by seminorms determined by continuous functions vanishing at in_nity. R. Giles ([13], p. 472, Theorem 4.6 proved in 1971 that the dual of C(T can be identi_ed with the space of regular Borel measures on T. We prove this result for positive, additive set-valued maps with values in the space of convex weakly compact non-empty subsets of a Banach space and we deduce from this result the theorem of R. Giles ([13], theorem 4.6, p.473.

  1. A Total Variation Model Based on the Strictly Convex Modification for Image Denoising

    Directory of Open Access Journals (Sweden)

    Boying Wu

    2014-01-01

    Full Text Available We propose a strictly convex functional in which the regular term consists of the total variation term and an adaptive logarithm based convex modification term. We prove the existence and uniqueness of the minimizer for the proposed variational problem. The existence, uniqueness, and long-time behavior of the solution of the associated evolution system is also established. Finally, we present experimental results to illustrate the effectiveness of the model in noise reduction, and a comparison is made in relation to the more classical methods of the traditional total variation (TV, the Perona-Malik (PM, and the more recent D-α-PM method. Additional distinction from the other methods is that the parameters, for manual manipulation, in the proposed algorithm are reduced to basically only one.

  2. Residual diffeomorphisms and symplectic soft hairs: The need to refine strict statement of equivalence principle

    Science.gov (United States)

    Sheikh-Jabbari, M. M.

    2016-09-01

    General covariance is the cornerstone of Einstein’s general relativity (GR) and implies that any two metrics related by diffeomorphisms are physically equivalent. There are, however, many examples pointing to the fact that this strict statement of general covariance needs refinement. There are a very special (measure-zero) subset of diffeomorphisms, the residual diffeomorphisms, to which one can associate well-defined conserved charges. This would hence render these diffeomorphic geometries physically distinct. We discuss that these symmetries may be appropriately called “symplectic symmetries”. Existence of residual diffeomorphisms and symplectic symmetries can be a quite general feature and not limited to the examples discussed so far in the literature. We propose that, in the context of black holes, these diffeomorphic, but distinct, geometries may be viewed as “symplectic soft hair” on black holes. We comment on how this may remedy black hole microstate problem, which in this context are dubbed as “horizon fluffs”.

  3. Reactions to terror attacks in ultra-orthodox jews: the cost of maintaining strict identity.

    Science.gov (United States)

    Ankri, Yael L E; Bachar, Eytan; Shalev, Arieh Y

    2010-01-01

    Traumatic events can shatter faith and beliefs. The responses of Ultra-Orthodox survivors of deadly terrorist attacks illustrate an effort to reconcile dreadful experiences with deeply embedded beliefs. Qualified clinicians prospectively evaluated self-reported and interviewer-generated posttraumatic stress disorder (PTSD) symptoms and cognitive appraisal in Ultra-Orthodox (n = 20) and non-Ultra-Orthodox (n = 33) survivors of suicide bus-bombing incidents in Jerusalem. Ultra-Orthodox survivors reported higher levels of PTSD symptoms and more personal guilt. Their narratives reflected an unshaken belief in Just Providence, within which being a victim of terror was perceived as a Just retribution for known or unknown wrongdoing. Survivors' reactions to trauma often reflect an effort to reconcile incongruous experiences with previously held beliefs. When treating strict believers, helpers should be sensitive to the identity-preserving function of posttraumatic cognitions.

  4. On a class of adjustable rate mortgage loans subject to a strict balance principle

    DEFF Research Database (Denmark)

    Astrup Jensen, Bjarne

    We describe the background and the basic funding mechanisms for the type of adjustable rate mortgageloans that were introduced in the Danish market in 1996. Each loan is funded separately by tap issuingpass-through mortgage bonds (`strict balance principle'). The novelty is a funding mechanism...... that usesa roll-over strategy, where long term loans are funded by sequentially issuing short term pass-throughbonds, and the first issuer of these loans obtained a patent on the funding principles in 1999. Publiclyavailable descriptions of the principles leave an impression of very complicated numerical...... algorithms.The algorithms described here show that the essentials can be reduced to a `back of an envelope' complexity.Keywords: Adjustable rate mortgages, balance principle, patent, yield curve riding...

  5. Nutritionally recommended food for semi- to strict vegetarian diets based on large-scale nutrient composition data.

    Science.gov (United States)

    Kim, Seunghyeon; Fenech, Michael F; Kim, Pan-Jun

    2018-03-12

    Diet design for vegetarian health is challenging due to the limited food repertoire of vegetarians. This challenge can be partially overcome by quantitative, data-driven approaches that utilise massive nutritional information collected for many different foods. Based on large-scale data of foods' nutrient compositions, the recent concept of nutritional fitness helps quantify a nutrient balance within each food with regard to satisfying daily nutritional requirements. Nutritional fitness offers prioritisation of recommended foods using the foods' occurrence in nutritionally adequate food combinations. Here, we systematically identify nutritionally recommendable foods for semi- to strict vegetarian diets through the computation of nutritional fitness. Along with commonly recommendable foods across different diets, our analysis reveals favourable foods specific to each diet, such as immature lima beans for a vegan diet as an amino acid and choline source, and mushrooms for ovo-lacto vegetarian and vegan diets as a vitamin D source. Furthermore, we find that selenium and other essential micronutrients can be subject to deficiency in plant-based diets, and suggest nutritionally-desirable dietary patterns. We extend our analysis to two hypothetical scenarios of highly personalised, plant-based methionine-restricted diets. Our nutrient-profiling approach may provide a useful guide for designing different types of personalised vegetarian diets.

  6. Strict Liability Versus Policy and Regulation for Environmental Protection and Agricultural Waste Management in Malaysia

    Directory of Open Access Journals (Sweden)

    Mohd Bakri Ishak

    2010-01-01

    Full Text Available Basically, strict liability is part of the mechanism for expressing judgment or sentence by using direct evidence. This principle is very useful in order to obtain remedies from any damage either directly or indirectly. The principle in Rylands v Fletcher is responsible on imposing strict liability where if something brought onto land or collected there escapes liability under this rule can include not only the owner of land but also those who control or occupation on it. However, as a matter of fact, policy and regulation are also important in taking any action against any party who are responsible for environmental pollution or damage, which may include mismanagement of waste or industrial waste or agricultural waste. There are certain policies and regulations on environmental protection such as the National Environmental Policy, certain Acts and several regulations under the Environmental Quality Act 1974 (Act 127, which are very useful for agricultural waste management inter alia: Waters Act 1920 (Act 418, Environmental Quality (Prescribed Premises (Crude Palm Oil Regulations 1977, Environmental Quality (Prescribed Premises (Raw Natural Rubber Regulations 1978, Environmental Quality (Sewage and Industrial Effluents Regulations 1979, and Environmental Quality (Compounding of Offences Rules 1978. As a matter of fact, we should realize that time is of an essence for any parties which are involved in court cases and especially in avoiding the element of externality, which is commonly suffered by the government. In making this paper, therefore, some element of comparison with certain developed jurisdiction such as in the United Kingdom and Japan could not be avoided in order to obtain better outcome and to be more practical for the purpose of environmental protection and agricultural waste management.

  7. The Effect of Strict Segregation on Pseudomonas aeruginosa in Cystic Fibrosis Patients.

    Directory of Open Access Journals (Sweden)

    Rosa van Mansfeld

    Full Text Available Segregation of patients with cystic fibrosis (CF was implemented to prevent chronic infection with epidemic Pseudomonas aeruginosa strains with presumed detrimental clinical effects, but its effectiveness has not been carefully evaluated.The effect of strict segregation on the incidence of P. aeruginosa infection in CF patients was investigated through longitudinal protocolized follow-up of respiratory tract infection before and after segregation. In two nested cross-sectional studies in 2007 and 2011 the P. aeruginosa population structure was investigated and clinical parameters were determined in patients with and without infection with the Dutch epidemic P. aeruginosa clone (ST406.Of 784 included patients 315 and 382 were at risk for acquiring chronic P. aeruginosa infection before and after segregation. Acquisition rates were, respectively, 0.14 and 0.05 per 1,000 days at risk (HR: 0.66, 95% CI [0.2548-1.541]; p = 0.28. An exploratory subgroup analysis indicated lower acquisition after segregation in children < 15 years of age (HR: 0.43, 95% CI[0.21-0.95]; p = 0.04. P. aeruginosa population structure did not change after segregation and ST406 was not associated with lung function decline, death or lung transplantation.Strict segregation was not associated with a statistically significant lower acquisition of chronic P. aeruginosa infection and ST406 was not associated with adverse clinical outcome. After segregation there were no new acquisitions of ST406. In an unplanned exploratory analysis chronic acquisition of P. aeruginosa was lower after implementation of segregation in patients under 15 years of age.

  8. Weight of fitness deviation governs strict physical chaos in replicator dynamics

    Science.gov (United States)

    Pandit, Varun; Mukhopadhyay, Archan; Chakraborty, Sagar

    2018-03-01

    Replicator equation—a paradigm equation in evolutionary game dynamics—mathematizes the frequency dependent selection of competing strategies vying to enhance their fitness (quantified by the average payoffs) with respect to the average fitnesses of the evolving population under consideration. In this paper, we deal with two discrete versions of the replicator equation employed to study evolution in a population where any two players' interaction is modelled by a two-strategy symmetric normal-form game. There are twelve distinct classes of such games, each typified by a particular ordinal relationship among the elements of the corresponding payoff matrix. Here, we find the sufficient conditions for the existence of asymptotic solutions of the replicator equations such that the solutions—fixed points, periodic orbits, and chaotic trajectories—are all strictly physical, meaning that the frequency of any strategy lies inside the closed interval zero to one at all times. Thus, we elaborate on which of the twelve types of games are capable of showing meaningful physical solutions and for which of the two types of replicator equation. Subsequently, we introduce the concept of the weight of fitness deviation that is the scaling factor in a positive affine transformation connecting two payoff matrices such that the corresponding one-shot games have exactly same Nash equilibria and evolutionary stable states. The weight also quantifies how much the excess of fitness of a strategy over the average fitness of the population affects the per capita change in the frequency of the strategy. Intriguingly, the weight's variation is capable of making the Nash equilibria and the evolutionary stable states, useless by introducing strict physical chaos in the replicator dynamics based on the normal-form game.

  9. Selvester scoring in patients with strict LBBB using the QUARESS software.

    Science.gov (United States)

    Xia, Xiaojuan; Chaudhry, Uzma; Wieslander, Björn; Borgquist, Rasmus; Wagner, Galen S; Strauss, David G; Platonov, Pyotr; Ugander, Martin; Couderc, Jean-Philippe

    2015-01-01

    Estimation of the infarct size from body-surface ECGs in post-myocardial infarction patients has become possible using the Selvester scoring method. Automation of this scoring has been proposed in order to speed-up the measurement of the score and improving the inter-observer variability in computing a score that requires strong expertise in electrocardiography. In this work, we evaluated the quality of the QuAReSS software for delivering correct Selvester scoring in a set of standard 12-lead ECGs. Standard 12-lead ECGs were recorded in 105 post-MI patients prescribed implantation of an implantable cardiodefibrillator (ICD). Amongst the 105 patients with standard clinical left bundle branch block (LBBB) patterns, 67 had a LBBB pattern meeting the strict criteria. The QuAReSS software was applied to these 67 tracings by two independent groups of cardiologists (from a clinical group and an ECG core laboratory) to measure the Selvester score semi-automatically. Using various level of agreement metrics, we compared the scores between groups and when automatically measured by the software. The average of the absolute difference in Selvester scores measured by the two independent groups was 1.4±1.5 score points, whereas the difference between automatic method and the two manual adjudications were 1.2±1.2 and 1.3±1.2 points. Eighty-two percent score agreement was observed between the two independent measurements when the difference of score was within two point ranges, while 90% and 84% score agreements were reached using the automatic method compared to the two manual adjudications. The study confirms that the QuAReSS software provides valid measurements of the Selvester score in patients with strict LBBB with minimal correction from cardiologists. Copyright © 2015 Elsevier Inc. All rights reserved.

  10. Host-to-host variation of ecological interactions in polymicrobial infections

    International Nuclear Information System (INIS)

    Mukherjee, Sayak; Seok, Sang-Cheol; Ray, Will C; Jayaprakash, C; Vieland, Veronica J; Das, Jayajit; Weimer, Kristin E; Swords, W Edward

    2015-01-01

    Host-to-host variability with respect to interactions between microorganisms and multicellular hosts are commonly observed in infection and in homeostasis. However, the majority of mechanistic models used to analyze host–microorganism relationships, as well as most of the ecological theories proposed to explain coevolution of hosts and microbes, are based on averages across a host population. By assuming that observed variations are random and independent, these models overlook the role of differences between hosts. Here, we analyze mechanisms underlying host-to-host variations of bacterial infection kinetics, using the well characterized experimental infection model of polymicrobial otitis media (OM) in chinchillas, in combination with population dynamic models and a maximum entropy (MaxEnt) based inference scheme. We find that the nature of the interactions between bacterial species critically regulates host-to-host variations in these interactions. Surprisingly, seemingly unrelated phenomena, such as the efficiency of individual bacterial species in utilizing nutrients for growth, and the microbe-specific host immune response, can become interdependent in a host population. The latter finding suggests a potential mechanism that could lead to selection of specific strains of bacterial species during the coevolution of the host immune response and the bacterial species. (paper)

  11. Strict follow-up programme including CT and (18) F-FDG-PET after curative surgery for colorectal cancer

    DEFF Research Database (Denmark)

    Sørensen, N F; Jensen, A B; Wille-Jørgensen, P

    2010-01-01

    Aim  The risk of local recurrence following curative surgery for colorectal cancer (CRC) is up to 50%. A rigorous follow-up program may increase survival. Guidelines on suitable methods for scheduled follow up examinations are needed. This study evaluates a strict follow-up program including...... supported a strict follow-up program following curative surgery for colorectal cancer. FDG-PET combined with CT should be included in control programs....

  12. Occurence and host specificity of indigenous rhizobia from soils of São Paulo State, Brazil Ocorrência de rizóbios nativos em plantas hospedeiras de solos nativos do Estado de São Paulo, Brasil

    Directory of Open Access Journals (Sweden)

    Maria Luiza Colognesi de Oliveira Lombardi

    2009-08-01

    Full Text Available The occurrence of rhizobial communities at four sites under natural vegetation and one site under pasture were examined. Isolates of rhizobia originating from crotalaria (C. junceae, common bean (Phaseolus vulgaris and pigeon pea (Cajanus cajan were studied in relation to population density, host specificity and the interaction between rhizobial occurrence, climatic conditions and soil properties. pH values and potential acidity were the soil properties that most affected rhizobial occurrence. Rhizobia from crotalaria and common bean were evaluated at four sites, and from pigeon pea, at five sites. Common bean was the most specific legume, followed by peanuts, crotalaria and pigeon pea.Foi examinada a ocorrência de comunidades de rizóbios em quatro locais de vegetação natural e um local de pastagem. Isolados de rizóbio originados de crotalária (C. junceae, feijão (Phaseolus vulgaris e guandu (Cajanus cajan foram estudados em relação à densidade populacional, planta hospedeira e interação entre ocorrência de rizóbio, condições climáticas e propriedades do solo. Os valores de pH e potencial de acidez foram as propriedades do solo que mais contribuíram para a ocorrência de rizóbio. A ocorrência de rizóbio em crotalária e feijão foi estudada em quatro locais, e em guandu em cinco locais. O feijão foi mais específico, seguido por crotalária e guandu.

  13. Molecular insight into systematics, host associations, life cycles and geographic distribution of the nematode family Rhabdiasidae.

    Science.gov (United States)

    Tkach, Vasyl V; Kuzmin, Yuriy; Snyder, Scott D

    2014-04-01

    zoogeographical regions. Serpentirhabdias, Entomelas and Pneumonema show rather strict specificity to their host groups. The evolution of the Rhabdiasidae clearly included multiple host switching events among different orders and families of amphibians as well as switching between amphibians and squamatan reptiles. Only a few smaller lineages of Rhabdias demonstrate relatively strict associations with a certain group of hosts. Copyright © 2014 Australian Society for Parasitology Inc. Published by Elsevier Ltd. All rights reserved.

  14. Magnetic resonance imaging quantitation of changes in muscle volume during 7 days of strict bed rest.

    Science.gov (United States)

    Ferrando, A A; Stuart, C A; Brunder, D G; Hillman, G R

    1995-10-01

    Prolonged bed rest results in a loss of leg lean body mass. Previous studies using bed rest as a model for microgravity have shown decreases in leg mass after 12 and 14 d, 5 and 17 wk. As magnetic resonance imaging (MRI) can provide a precise and non-invasive means of determining muscle volume, we sought to determine if changes in leg muscle volume could be detected in bed rest periods as short as 7 d. Five young, healthy, male volunteers were subjected to 7 d of absolute bed rest. Each subject underwent MRI quantitation of segmental muscle volumes of the calves and thighs before and after bed rest. Eleven (calf) and nine (thigh) contiguous 1-cm thick transaxial images were generated over prescribed regions using a Technicare MRI imager with a 0.6T superconducting magnet and body coil. Image processing was performed using a generalized 8-bit medical image analysis package developed at University of Texas Medical Branch. Images were analyzed for muscle and non-muscle volumes (including fat, blood vessel, and bone marrow volumes). The MRI quantitation demonstrated bed rest-induced significant decreases in segmental thigh muscle (approximately 3.0%, p image analysis of MRI images provides a sensitive tool capable of detecting leg volume changes of as little as 3.0% over a 7-d period of strict bed rest.

  15. Managing curriculum transformation within strict university governance structures: an example from Damascus University Medical School.

    Science.gov (United States)

    Kayyal, Mohammad; Gibbs, Trevor

    2012-01-01

    As the world of medical education moves forward, it becomes increasingly clear that the transformative process is not as easy a process for all. Across the globe, there appears to be many barriers that obstruct or threaten innovation and change, most of which cause almost insurmountable problems to many schools. If transformative education is to result in an equitable raising of standards across such an unlevel playing field, schools have to find ways in overcoming these barriers. One seemingly common barrier to development occurs when medical schools are trapped within strict University governance structures; rules and regulations which are frequently inappropriate and obstructive to the transformation that must occur in today's medical educational paradigm. The Faculty of Medicine at Damascus University, one of the oldest and foremost medical schools in the Middle East, is one such school where rigid rules and regulations and traditional values are obstructing transformative change. This paper describes the problems, which the authors believe to be common to many, and explores how attempts have been made to overcome them and move the school into the twenty-first century. It is the ultimate purpose of this paper to raise awareness of the issue, share the lessons learned in order to assist others who are experiencing similar problems and possibly create opportunities for dialogue between schools.

  16. On a holomorphic Lefschetz formula in strictly pseudoconvex subdomains of complex manifolds

    International Nuclear Information System (INIS)

    Kytmanov, A M; Myslivets, S G; Tarkhanov, N N

    2004-01-01

    The classical Lefschetz formula expresses the number of fixed points of a continuous map f:M→M in terms of the transformation induced by f on the cohomology of M. In 1966, Atiyah and Bott extended this formula to elliptic complexes over a compact closed manifold. In particular, they obtained a holomorphic Lefschetz formula on compact complex manifolds without boundary. Brenner and Shubin (1981, 1991) extended the Atiyah-Bott theory to compact manifolds with boundary. On compact complex manifolds with boundary the Dolbeault complex is not elliptic, therefore the Atiyah-Bott theory is not applicable. Bypassing difficulties related to the boundary behaviour of Dolbeault cohomology, Donnelly and Fefferman (1986) obtained a formula for the number of fixed points in terms of the Bergman metric. The aim of this paper is to obtain a Lefschetz formula on relatively compact strictly pseudoconvex subdomains of complex manifolds X with smooth boundary, that is, to find the total Lefschetz number for a holomorphic endomorphism f * of the Dolbeault complex and to express it in terms of local invariants of the fixed points of f.

  17. Divergent changes in serum sterols during a strict uncooked vegan diet in patients with rheumatoid arthritis.

    Science.gov (United States)

    Agren, J J; Tvrzicka, E; Nenonen, M T; Helve, T; Hänninen, O

    2001-02-01

    The effects of a strict uncooked vegan diet on serum lipid and sterol concentrations were studied in patients with rheumatoid arthritis. The subjects were randomized into a vegan diet group (n 16), who consumed a vegan diet for 2-3 months, or into a control group (n 13), who continued their usual omnivorous diets. Serum total and LDL-cholesterol and -phospholipid concentrations were significantly decreased by the vegan diet. The levels of serum cholestanol and lathosterol also decreased, but serum cholestanol:total cholesterol and lathosterol:total cholesterol did not change. The effect of a vegan diet on serum plant sterols was divergent as the concentration of campesterol decreased while that of sitosterol increased. This effect resulted in a significantly greater sitosterol:campesterol value in the vegan diet group than in the control group (1.48 (SD 0.39) v. 0.72 (SD 0.14); P vegan diet changes the relative absorption rates of these sterols and/or their biliary clearance.

  18. Model-Based Adaptive Event-Triggered Control of Strict-Feedback Nonlinear Systems.

    Science.gov (United States)

    Li, Yuan-Xin; Yang, Guang-Hong

    2018-04-01

    This paper is concerned with the adaptive event-triggered control problem of nonlinear continuous-time systems in strict-feedback form. By using the event-sampled neural network (NN) to approximate the unknown nonlinear function, an adaptive model and an associated event-triggered controller are designed by exploiting the backstepping method. In the proposed method, the feedback signals and the NN weights are aperiodically updated only when the event-triggered condition is violated. A positive lower bound on the minimum intersample time is guaranteed to avoid accumulation point. The closed-loop stability of the resulting nonlinear impulsive dynamical system is rigorously proved via Lyapunov analysis under an adaptive event sampling condition. In comparing with the traditional adaptive backstepping design with a fixed sample period, the event-triggered method samples the state and updates the NN weights only when it is necessary. Therefore, the number of transmissions can be significantly reduced. Finally, two simulation examples are presented to show the effectiveness of the proposed control method.

  19. Strictly hyperbolic models of co-current three-phase flow withgravity

    Energy Technology Data Exchange (ETDEWEB)

    Juanes, Ruben; Patzek, Tadeusz W.

    2002-11-18

    We study the character of the equations in the traditional formulation of one-dimensional immiscible three-phase flow with gravity, in the limit of negligible capillarity. We restrict our analysis to co-current flow required for a displacement process; in cases of mixed co-current and counter-current flow, capillarity effects cannot be dropped from the formulation. The model makes use of the classical multiphase extension of Darcy's equation. It is well known that, if relative permeabilities are taken as fixed functions of saturations, the model yields regions in the saturation space where the system of equations is locally elliptic. We regard elliptic behavior as a nonphysical artifact of an incomplete formulation, and derive conditions on the relative permeabilities that ensure strict hyperbolicity of the governing equations. The key point is to acknowledge that a Darcy-type formulation is insufficient to capture all the physics of three-phase flow and that, consequently, the relative permeabilities are functionals that depend on the fluid viscosity ratio and the gravity number. The derived conditions are consistent with the type of displacements that take place in porous media. By means of an illustrative example, we show how elliptic behavior can be removed, even when using simplistic relative permeability models.

  20. Clinical impact of strict criteria for selectivity and lateralization in adrenal vein sampling.

    Science.gov (United States)

    Gasparetto, Alessandro; Angle, John F; Darvishi, Pasha; Freeman, Colbey W; Norby, Ray G; Carey, Robert M

    2015-04-01

    Selectivity index (SI) and lateralization index (LI) thresholds determine the adequacy of adrenal vein sampling (AVS) and the degree of lateralization. The purpose of this study was investigate the clinical outcome of patients whose adrenal vein sampling was interpreted using "strict criteria" (SC) (SIpre-stimuli≥3, SIpost-stimuli≥5 and LIpre-stimuli≥4, LIpost-stimuli≥4). A retrospective review of 73 consecutive AVS procedures was performed and 67 were technically successful. Forty-three patients showed lateralization and underwent surgery, while 24 did not lateralize and were managed conservatively. Systolic blood pressure (SBP), diastolic blood pressure (DBP), kalemia (K(+)), and the change in number of blood pressure (BP) medications were recorded for each patient before and after AVS and potential surgery were performed. In the surgery group, BP and K(+) changed respectively from 160±5.3/100±2.0 mmHg to 127±3.3/80±1.9 (p blood pressure medications were six (14.0%) in the lateralized group and 22 (91.7%) in the non-lateralized group (p <0.001). AVS interpretation with SC leads to significant clinical improvement in both patients who underwent surgery and those managed conservatively.

  1. Generalized selection to overcome innate immunity selects for host breadth in an RNA virus.

    Science.gov (United States)

    Wasik, Brian R; Muñoz-Rojas, Andrés R; Okamoto, Kenichi W; Miller-Jensen, Kathryn; Turner, Paul E

    2016-02-01

    Virus-host coevolution has selected for generalized host defense against viruses, exemplified by interferon production/signaling and other innate immune function in eukaryotes such as humans. Although cell-surface binding primarily limits virus infection success, generalized adaptation to counteract innate immunity across disparate hosts may contribute to RNA virus emergence potential. We examined this idea using vesicular stomatitis virus (VSV) populations previously evolved on strictly immune-deficient (HeLa) cells, strictly immune competent (MDCK) cells, or on alternating deficient/competent cells. By measuring viral fitness in unselected human cancer cells of differing innate immunity, we confirmed that HeLa-adapted populations were specialized for innate immune-deficient hosts, whereas MDCK-adapted populations were relatively more generalized for fitness on hosts of differing innate immune capacity and of different species origin. We also confirmed that HeLa-evolved populations maintained fitness in immune-deficient nonhuman primate cells. These results suggest that innate immunity is more prominent than host species in determining viral fitness at the host-cell level. Finally, our prediction was inexact that selection on alternating deficient/competent hosts should produce innate viral generalists. Rather, fitness differences among alternating host-evolved VSV populations indicated variable capacities to evade innate immunity. Our results suggest that the evolutionary history of innate immune selection can affect whether RNA viruses evolve greater host-breadth. © 2016 The Author(s). Evolution © 2016 The Society for the Study of Evolution.

  2. Genome-wide sequence data suggest the possibility of pollinator sharing by host shift in dioecious figs (Moraceae, Ficus).

    Science.gov (United States)

    Wachi, Nakatada; Kusumi, Junko; Tzeng, Hsy-Yu; Su, Zhi-Hui

    2016-11-01

    The obligate mutualism of figs and fig-pollinating wasps has been one of the classic models used for testing theories of co-evolution and cospeciation due to the high species-specificity of these relationships. To investigate the species-specificity between figs and fig pollinators and to further understand the speciation process in obligate mutualisms, we examined the genetic differentiation and phylogenetic relationships of four closely related fig-pollinating wasp species (Blastophaga nipponica, Blastophaga taiwanensis, Blastophaga tannoensis and Blastophaga yeni) in Japan and Taiwan using genome-wide sequence data, including mitochondrial DNA sequences. In addition, population structure was analysed for the fig wasps and their host species using microsatellite data. The results suggest that the three Taiwanese fig wasp species are a single panmictic population that pollinates three dioecious fig species, which are sympatrically distributed, have large differences in morphology and ecology and are also genetically differentiated. Our results illustrate the first case of pollinator sharing by host shift in the subgenus Ficus. On the other hand, there are strict genetic codivergences between allopatric populations of the two host-pollinator pairs. The possible processes that produce these pollinator-sharing events are discussed based on the level and pattern of genetic differentiation in these figs and fig wasps. © 2016 John Wiley & Sons Ltd.

  3. Sporothrix schenckii (sensu strict S. globosa) mating type 1-2 (MAT1-2) gene.

    Science.gov (United States)

    Kano, Rui; Anzawa, Kazushi; Mochizuki, Takashi; Nishimoto, Katsutaro; Hiruma, Masataro; Kamata, Hiroshi; Hasegawa, Atsuhiko

    2013-09-01

    Sporotix schenckii is a pathogenic fungus that causes human and animal sporotrichosis, and based on morphology of the sessile conidia and molecular analysis, it was recently recognized as a species complex comprising at least the following six sibling species: S. albicans, S. brasiliensis, S. globosa, S. luriei, S. mexicana and S. schenckii. However, apart from S. schenckii sensu strict, only S. brasiliensis, S. globosa and S. luriei are associated with human and animal infection. S. globosa has been most commonly isolated in Asia, Europe and the USA; therefore, molecular epidemiological study for S. globosa is important in relation to human sporotrichosis in Japan. To the best of our knowledge, this is the first study to determine the mating type 1-2 (MAT1-2) gene of Sporothrix schenckii with the aim of understanding the taxonomy of the genus Sporothrix. The MAT1-2 gene (1618 bp) encodes a protein sequence of 198 amino acids. Reverse transcription polymerase chain reaction analysis also detected MAT1-2 gene mRNA expression in all of the S. schenckii strains examined, indicating that this gene is expressed in S. schenckii cells. Phylogenetic analysis of the MAT1-2 gene fragments of Ophiostoma himal-ulmi, O. novo-ulmi, O. ulmi and S. schenckii indicated that these isolates could be classified into four clusters. MAT1-1 gene-specific polymerase chain reaction was positive in 15 isolates, but negative in four human isolates and one feline isolate. © 2013 Japanese Dermatological Association.

  4. Strict Criteria for Selection of Laparoscopy for Women with Adnexal Mass

    Science.gov (United States)

    Sallum, Luis Felipe; Sarian, Luis Otávio; Bastos, Joana Fróes Bragança; Derchain, Sophie

    2014-01-01

    Objectives: We compared the indication of laparoscopy for treatment of adnexal masses based on the risk scores and tumor diameters with the indication based on gynecology-oncologists' experience. Methods: This was a prospective study of 174 women who underwent surgery for adnexal tumors (116 laparotomies, 58 laparoscopies). The surgeries begun and completed by laparoscopy, with benign pathologic diagnosis, were considered successful. Laparoscopic surgeries that required conversion to laparotomy, led to a malignant diagnosis, or facilitated cyst rupture were considered failures. Two groups were defined for laparoscopy indication: (1) absence of American College of Obstetrics and Gynecology (ACOG) guideline for referral of high-risk adnexal masses criteria (ACOG negative) associated with 3 different tumor sizes (10, 12, and 14 cm); and (2) Index of Risk of Malignancy (IRM) with cutoffs at 100, 200, and 300, associated with the same 3 tumor sizes. Both groups were compared with the indication based on the surgeon's experience to verify whether the selection based on strict rules would improve the rate of successful laparoscopy. Results: ACOG-negative and tumors ≤10 cm and IRM with a cutoff at 300 points and tumors ≤10cm resulted in the same best performance (78% success = 38/49 laparoscopies). However, compared with the results of the gynecology-oncologists' experience, those were not statistically significant. Discussion: The selection of patients with adnexal mass to laparoscopy by the use of the ACOG guideline or IRM associated with tumor diameter had similar performance as the experience of gynecology-oncologists. Both methods are reproducible and easy to apply to all women with adnexal masses and could be used by general gynecologists to select women for laparoscopic surgery; however, referral to a gynecology-oncologist is advisable when there is any doubt. PMID:25392617

  5. The conserved clag multigene family of malaria parasites: essential roles in host-pathogen interaction.

    Science.gov (United States)

    Gupta, Ankit; Thiruvengadam, Girija; Desai, Sanjay A

    2015-01-01

    The clag multigene family is strictly conserved in malaria parasites, but absent from neighboring genera of protozoan parasites. Early research pointed to roles in merozoite invasion and infected cell cytoadherence, but more recent studies have implicated channel-mediated uptake of ions and nutrients from host plasma. Here, we review the current understanding of this gene family, which appears to be central to host-parasite interactions and an important therapeutic target. Published by Elsevier Ltd.

  6. Rodent hosts of Maritrema sp. (Digenea, Microphallidae in Sardinia Island

    Directory of Open Access Journals (Sweden)

    Juan Carlos Casanova

    2003-10-01

    Full Text Available Prospections on helminth fauna of rodents were carried out in the Cedrino river (Eastern of Sardinia island. Twelve Rattus rattus (L., 1758 and eight Mus domesticus (Schwarz & Schwarz, 1943 were captured by Sherman traps. Parasitological study revealed in R. rattus the presence of an intestinal helminth belonging to the genus Maritrema (family Microphallidae. The transmission of this Digenetic Trematode among vertebrates involves the participation of aquatic invertebrate organisms, molluscs and crustacea, acting as intermediate hosts. Dissection of 117 individuals of the Amphipod Crustacea Gammarus italicus, collected in the same biotope, allowed the detection of encysted metacercariae. These larvae constitute the infesting stage of the parasite for vertebrates, acting these as definitive hosts ingesting parasitized crustacea as preys. Adults of Maritrema sp. were also obtained experimentally in the laboratory mice (Mus domesticus CD1 strain. These were infested by inoculating them, using gastric probe, metacercarial cysts isolated from G. italicus. Post-infection mice dissection was performed at different intervals of time getting adults in various maturity stages. Experimental facts confirm that Maritrema sp., as it occurs in other trematodes, do not present strict specificity to the definitive host, being able to develop as well in Mus. In nature, the presence or absence of this digenean in mammals species will be dependent of host ethological factors, mainly related to feeding habitats. This study was partially supported by the ?Comissionat per Recerca i Universitats de la Generalitat de Catalunya? 2001SGR00088.

  7. Properties of N-person axiomatic bargaining solutions if the Pareto frontier is twice differentiable and strictly concave

    NARCIS (Netherlands)

    Douven, R.C.M.H.; Engwerda, J.C.

    1995-01-01

    In this paper we discuss properties of N-person axiomatic bargaining problems, where the Pareto frontier of S can be described by a strictly concave and twice differentiable function. These type of problems are characteristic for the empirical policy coordination literature. In that literature the

  8. Convergence of Implicit and Explicit Schemes for an Asymptotically Nonexpansive Mapping in -Uniformly Smooth and Strictly Convex Banach Spaces

    Directory of Open Access Journals (Sweden)

    Meng Wen

    2012-01-01

    Full Text Available We introduce a new iterative scheme with Meir-Keeler contractions for an asymptotically nonexpansive mapping in -uniformly smooth and strictly convex Banach spaces. We also proved the strong convergence theorems of implicit and explicit schemes. The results obtained in this paper extend and improve many recent ones announced by many others.

  9. A non-permselective membrane reactor for chemical processes normally requiring strict stoichiometric feed rates of reactants

    NARCIS (Netherlands)

    Sloot, H.J.; Versteeg, Geert; van Swaaij, Willibrordus Petrus Maria

    1990-01-01

    A novel type of membrane reactor with separated feeding of the reactants is presented for chemical processes normally requiring strict stoichiometric feed rates of premixed reactants. The reactants are fed in the reactor to the different sides of a porous membrane which is impregnated with a

  10. Strict Fathers, Competing Culture(s), and Racialized Poverty: White South African Teachers' Conceptions of Themselves as Racialized Actors

    Science.gov (United States)

    Casey, Zachary A.

    2016-01-01

    This article focuses in particular on four white South African female practicing P-12 teachers' narratives about their own racialized understanding of their classroom practice(s) and their (racio-cultural) self-identity. Each of the four participants reported growing up with what they described as "strict fathers" and shared ways in…

  11. DNA barcoding insect-host plant associations.

    Science.gov (United States)

    Jurado-Rivera, José A; Vogler, Alfried P; Reid, Chris A M; Petitpierre, Eduard; Gómez-Zurita, Jesús

    2009-02-22

    Short-sequence fragments ('DNA barcodes') used widely for plant identification and inventorying remain to be applied to complex biological problems. Host-herbivore interactions are fundamental to coevolutionary relationships of a large proportion of species on the Earth, but their study is frequently hampered by limited or unreliable host records. Here we demonstrate that DNA barcodes can greatly improve this situation as they (i) provide a secure identification of host plant species and (ii) establish the authenticity of the trophic association. Host plants of leaf beetles (subfamily Chrysomelinae) from Australia were identified using the chloroplast trnL(UAA) intron as barcodes amplified from beetle DNA extracts. Sequence similarity and phylogenetic analyses provided precise identifications of each host species at tribal, generic and specific levels, depending on the available database coverage in various plant lineages. The 76 species of Chrysomelinae included-more than 10 per cent of the known Australian fauna-feed on 13 plant families, with preference for Australian radiations of Myrtaceae (eucalypts) and Fabaceae (acacias). Phylogenetic analysis of beetles shows general conservation of host association but with rare host shifts between distant plant lineages, including a few cases where barcodes supported two phylogenetically distant host plants. The study demonstrates that plant barcoding is already feasible with the current publicly available data. By sequencing plant barcodes directly from DNA extractions made from herbivorous beetles, strong physical evidence for the host association is provided. Thus, molecular identification using short DNA fragments brings together the detection of species and the analysis of their interactions.

  12. Animal salmonelloses: a brief review of “host adaptation and host specificity” of Salmonella spp.

    Directory of Open Access Journals (Sweden)

    Grammato Evangelopoulou

    2013-07-01

    Full Text Available Salmonella enterica, the most pathogenic species of the genusSalmonella, includes more than 2,500 serovars, many of which are of great veterinary and medical significance. The emergence of food-borne pathogens, such as Salmonella spp., has increased knowledge about the mechanisms helping microorganisms to persist and spread within new host populations. It has also increased information about the properties they acquire for adapting in the biological environment of a new host. Thedifferences observed between serovars in their host preference and clinical manifestations are referred to as “serovar-host specificity” or “serovar-host adaptation”. The genus Salmonella, highly adaptive to vertebrate hosts, has many pathogenic serovars showing host specificity. Serovar Salmonella Typhi, causing disease to man and higher primates, is a good example of host specificity. Thus, understanding the mechanisms that Salmonella serovars use to overcome animal species' barriers or adapt to new hosts is also important for understanding the origins of any other infectious diseases or the emergence of new pathogens. In addition, molecular methods used to study the virulence determinants of Salmonella serovars, could also be used to model ways of studying the virulence determinants used by bacteria in general, when causing disease to a specific animal species

  13. Identité stricte ou partielle et identification dans les phrases à copule. Comment les identifier ?

    Directory of Open Access Journals (Sweden)

    Amary-Coudreau Valérie

    2014-07-01

    éristiques propres à l’identité, ainsi que celles propres à la spécification et à l’identification, pour lesquelles X et Y ont des degrés de référentialité et/ou de prédicativité différents. Enfin, cette hypothèse nous amène à distinguer l’identité de l’identification, sur la base de tests qui, à l’inverse de Larreya (2003, différencient l’identité stricte de l’identité partielle.

  14. Optimization of an effective growth medium for culturing probiotic bacteria for applications in strict vegetarian food products

    Directory of Open Access Journals (Sweden)

    Manju Pathak

    2012-10-01

    Full Text Available Background: This study aimed to modify de Man Rogosa Sharpe culture medium (termed MRS for selective cultivation of probiotics strain for the consumption by the strictly vegetarian human population. Vegetarian probiotic foods by definition must be free from all animal-derived ingredients. This not only includes the product ingredients but the probiotic inoculum as well. Probiotic starter cultures are traditionally grown and stored in media containing milk or meatderived ingredients. The presence of these ingredients makes the probiotic cell concentrates unsuitable for use in vegetarian products and thus creates the need for a growth medium which isfree from animal-derived ingredients. Present study investigated the growth of a strain of Lactobacillus lactis in MRS. The present invention relates in general to a bacterial culture media,and more specifically a complex microbial culture media, based on plant seed powder extract in place of animal extract for probiotic bacterial growth.Methods: Lactobacillus lactis, a probiotic, was grown in standard MRS culture medium as well as in our various test media (TM containing various vegetal source in place of beef extract, yeast extract and peptone as in case of MRS. The inoculated culture mediums were incubated at 37C for 72 hours and growth of probiotic is recorded at regular intervals. The growth was recorded as Colony Forming Units (CFUs.Results: The best growth of probiotic is observed in TM 2. TM 2 is the leguminous seed extract. Starter culture mediums for probiotics or other bacteria primarily contain protein from animal source. The possibility of using vegetal protein from TM 2 extract in place of peptones and meat extract for the nitrogen supplementation of culture media for the growth of lactic acid bacteria has been demonstrated.Functional Foods in Health and Disease 2012, 2(10:369-378 Conclusion: The absolute vegetarian culture medium containing TM 2 is better than standard MRS for the

  15. The Poxvirus C7L Host Range Factor Superfamily

    OpenAIRE

    Liu, Jia; Rothenburg, Stefan; McFadden, Grant

    2012-01-01

    Host range factors, expressed by the poxvirus family, determine the host tropism of species, tissue, and cell specificity. C7L family members exist in the genomes of most sequenced mammalian poxviruses, suggesting an evolutionarily conserved effort adapting to the hosts. In general, C7L orthologs influence the host tropism in mammalian cell culture, and for some poxviruses it is essential for the complete viral life cycle in vitro and in vivo. The C7L family members lack obvious sequence homo...

  16. Strict liability as a legal mechanism protecting the aggrieved parties' interests within the nuclear liability regime

    International Nuclear Information System (INIS)

    Novotna, Marianna

    2016-01-01

    The no-fault liability principle of nuclear liability regime, its compensation schemes, sociological and legal grounds of its construction as well as liberation grounds are analysed. The simple existence of causation of damage and nuclear accident without necessity of proving negligence or any other type of fault on the part of the operator as an adequate basis for the operator’s strict liability is highlighted thus simplifying the litigation process eliminating potential obstacles, especially such as might exist with the burden of proof. The question of weighing the interests of society in the development of nuclear industry, the necessary extent of protection of victims of nuclear accidents and the interests of operators of nuclear facilities as main determinants of the strict nature of nuclear liability is also described. (orig.)

  17. The impact of Sleep Time-Related Information and Communication Technology (STRICT) on sleep patterns and daytime functioning in American adolescents.

    Science.gov (United States)

    Polos, Peter G; Bhat, Sushanth; Gupta, Divya; O'Malley, Richard J; DeBari, Vincent A; Upadhyay, Hinesh; Chaudhry, Saqib; Nimma, Anitha; Pinto-Zipp, Genevieve; Chokroverty, Sudhansu

    2015-10-01

    This cross-sectional study explored the extent and impact of mobile device-based Sleep Time-Related Information and Communication Technology (STRICT) use among American adolescents (N = 3139, 49.3% female, mean age = 13.3 years). Nearly 62% used STRICT after bedtime, 56.7% texted/tweeted/messaged in bed, and 20.8% awoke to texts. STRICT use was associated with insomnia, daytime sleepiness, eveningness, academic underperformance, later bedtimes and shorter sleep duration. Moderation analysis demonstrated that the association between STRICT use and insomnia increased with age, the association between STRICT use and daytime sleepiness decreased with age, and the association between STRICT use and shorter sleep duration decreased with age and was stronger in girls. Insomnia and daytime sleepiness partially mediated the relationship between STRICT use and academic underperformance. Our results illustrate the adverse interactions between adolescent STRICT use and sleep, with deleterious effects on daytime functioning. These worrisome findings suggest that placing reasonable limitations on adolescent STRICT use may be appropriate. Copyright © 2015 The Foundation for Professionals in Services for Adolescents. Published by Elsevier Ltd. All rights reserved.

  18. Bacterial subversion of host innate immune pathways.

    Science.gov (United States)

    Baxt, Leigh A; Garza-Mayers, Anna Cristina; Goldberg, Marcia B

    2013-05-10

    The pathogenesis of infection is a continuously evolving battle between the human host and the infecting microbe. The past decade has brought a burst of insights into the molecular mechanisms of innate immune responses to bacterial pathogens. In parallel, multiple specific mechanisms by which microorganisms subvert these host responses have been uncovered. This Review highlights recently characterized mechanisms by which bacterial pathogens avoid killing by innate host responses, including autophagy pathways and a proinflammatory cytokine transcriptional response, and by the manipulation of vesicular trafficking to avoid the toxicity of lysosomal enzymes.

  19. Identity and diversity of blood meal hosts of biting midges (Diptera: Ceratopogonidae: Culicoides Latreille in Denmark

    Directory of Open Access Journals (Sweden)

    Lassen Sandra B

    2012-07-01

    Full Text Available Abstract Background Host preference studies in haematophagous insects e.g. Culicoides biting midges are pivotal to assess transmission routes of vector-borne diseases and critical for the development of veterinary contingency plans to identify which species should be included due to their risk potential. Species of Culicoides have been found in almost all parts of the world and known to live in a variety of habitats. Several parasites and viruses are transmitted by Culicoides biting midges including Bluetongue virus and Schmallenberg virus. The aim of the present study was to determine the identity and diversity of blood meals taken from vertebrate hosts in wild-caught Culicoides biting midges near livestock farms. Methods Biting midges were collected at weekly intervals for 20 weeks from May to October 2009 using light traps at four collection sites on the island Sealand, Denmark. Blood-fed female biting midges were sorted and head and wings were removed for morphological species identification. The thoraxes and abdomens including the blood meals of the individual females were subsequently subjected to DNA isolation. The molecular marker cytochrome oxidase I (COI barcode was applied to identify the species of the collected biting midges (GenBank accessions JQ683259-JQ683374. The blood meals were first screened with a species-specific cytochrome b primer pair for cow and if negative with a universal cytochrome b primer pair followed by sequencing to identify mammal or avian blood meal hosts. Results Twenty-four species of biting midges were identified from the four study sites. A total of 111,356 Culicoides biting midges were collected, of which 2,164 were blood-fed. Specimens of twenty species were identified with blood in their abdomens. Blood meal sources were successfully identified by DNA sequencing from 242 (76% out of 320 Culicoides specimens. Eight species of mammals and seven species of birds were identified as blood meal hosts. The

  20. Strict versus liberal target range for perioperative glucose in patients undergoing coronary artery bypass grafting: a prospective randomized controlled trial.

    Science.gov (United States)

    Desai, Shalin P; Henry, Linda L; Holmes, Sari D; Hunt, Sharon L; Martin, Chidima T; Hebsur, Shrinivas; Ad, Niv

    2012-02-01

    The purpose of this study was to test the hypothesis that a liberal blood glucose strategy (121-180 mg/dL) is not inferior to a strict blood glucose strategy (90-120 mg/dL) for outcomes in patients after first-time isolated coronary artery bypass grafting and is superior for glucose control and target blood glucose management. A total of 189 patients undergoing coronary artery bypass grafting were investigated in this prospective randomized study to compare 2 glucose control strategies on patient perioperative outcomes. Three methods of analyses (intention to treat, completer, and per protocol) were conducted. Observed power was robust (>80%) for significant results. The groups were similar on preoperative hemoglobin A(1c) and number of diabetic patients. The liberal group was found to be noninferior to the strict group for perioperative complications and superior on glucose control and target range management. The liberal group had significantly fewer patients with hypoglycemic events (liberal range after coronary artery bypass grafting led to similar outcomes compared with a strict target range and was superior in glucose control and target range management. On the basis of the results of this study, a target blood glucose range of 121 to 180 mg/dL is recommended for patients after coronary artery bypass grafting as advocated by the Society of Thoracic Surgeons. Copyright © 2012 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  1. Host jumps shaped the diversity of extant rust fungi (Pucciniales).

    Science.gov (United States)

    McTaggart, Alistair R; Shivas, Roger G; van der Nest, Magriet A; Roux, Jolanda; Wingfield, Brenda D; Wingfield, Michael J

    2016-02-01

    The aim of this study was to determine the evolutionary time line for rust fungi and date key speciation events using a molecular clock. Evidence is provided that supports a contemporary view for a recent origin of rust fungi, with a common ancestor on a flowering plant. Divergence times for > 20 genera of rust fungi were studied with Bayesian evolutionary analyses. A relaxed molecular clock was applied to ribosomal and mitochondrial genes, calibrated against estimated divergence times for the hosts of rust fungi, such as Acacia (Fabaceae), angiosperms and the cupressophytes. Results showed that rust fungi shared a most recent common ancestor with a mean age between 113 and 115 million yr. This dates rust fungi to the Cretaceous period, which is much younger than previous estimations. Host jumps, whether taxonomically large or between host genera in the same family, most probably shaped the diversity of rust genera. Likewise, species diversified by host shifts (through coevolution) or via subsequent host jumps. This is in contrast to strict coevolution with their hosts. Puccinia psidii was recovered in Sphaerophragmiaceae, a family distinct from Raveneliaceae, which were regarded as confamilial in previous studies. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  2. Host Identity Protocol Proxy

    Science.gov (United States)

    Salmela, Patrik; Melén, Jan

    The Host Identity Protocol (HIP) is one of the more recent designs that challenge the current Internet architecture. The main features of HIP are security and the identifier-locator split, which solves the problem of overloading the IP address with two separate tasks. This paper studies the possibility of providing HIP services to legacy hosts via a HIP proxy. Making a host HIP enabled requires that the IP-stack of the host is updated to support HIP. From a network administrator's perspective this can be a large obstacle. However, by providing HIP from a centralized point, a HIP proxy, the transition to begin using HIP can be made smoother. This and other arguments for a HIP proxy will be presented in this paper along with an analysis of a prototype HIP proxy and its performance.

  3. Poxvirus Host Range Genes and Virus-Host Spectrum: A Critical Review.

    Science.gov (United States)

    Oliveira, Graziele Pereira; Rodrigues, Rodrigo Araújo Lima; Lima, Maurício Teixeira; Drumond, Betânia Paiva; Abrahão, Jônatas Santos

    2017-11-07

    The Poxviridae family is comprised of double-stranded DNA viruses belonging to nucleocytoplasmic large DNA viruses (NCLDV). Among the NCLDV, poxviruses exhibit the widest known host range, which is likely observed because this viral family has been more heavily investigated. However, relative to each member of the Poxviridae family, the spectrum of the host is variable, where certain viruses can infect a large range of hosts, while others are restricted to only one host species. It has been suggested that the variability in host spectrum among poxviruses is linked with the presence or absence of some host range genes. Would it be possible to extrapolate the restriction of viral replication in a specific cell lineage to an animal, a far more complex organism? In this study, we compare and discuss the relationship between the host range of poxvirus species and the abundance/diversity of host range genes. We analyzed the sequences of 38 previously identified and putative homologs of poxvirus host range genes, and updated these data with deposited sequences of new poxvirus genomes. Overall, the term host range genes might not be the most appropriate for these genes, since no correlation between them and the viruses' host spectrum was observed, and a change in nomenclature should be considered. Finally, we analyzed the evolutionary history of these genes, and reaffirmed the occurrence of horizontal gene transfer (HGT) for certain elements, as previously suggested. Considering the data presented in this study, it is not possible to associate the diversity of host range factors with the amount of hosts of known poxviruses, and this traditional nomenclature creates misunderstandings.

  4. Host reproductive phenology drives seasonal patterns of host use in mosquitoes.

    Directory of Open Access Journals (Sweden)

    Nathan D Burkett-Cadena

    2011-03-01

    Full Text Available Seasonal shifts in host use by mosquitoes from birds to mammals drive the timing and intensity of annual epidemics of mosquito-borne viruses, such as West Nile virus, in North America. The biological mechanism underlying these shifts has been a matter of debate, with hypotheses falling into two camps: (1 the shift is driven by changes in host abundance, or (2 the shift is driven by seasonal changes in the foraging behavior of mosquitoes. Here we explored the idea that seasonal changes in host use by mosquitoes are driven by temporal patterns of host reproduction. We investigated the relationship between seasonal patterns of host use by mosquitoes and host reproductive phenology by examining a seven-year dataset of blood meal identifications from a site in Tuskegee National Forest, Alabama USA and data on reproduction from the most commonly utilized endothermic (white-tailed deer, great blue heron, yellow-crowned night heron and ectothermic (frogs hosts. Our analysis revealed that feeding on each host peaked during periods of reproductive activity. Specifically, mosquitoes utilized herons in the spring and early summer, during periods of peak nest occupancy, whereas deer were fed upon most during the late summer and fall, the period corresponding to the peak in births for deer. For frogs, however, feeding on early- and late-season breeders paralleled peaks in male vocalization. We demonstrate for the first time that seasonal patterns of host use by mosquitoes track the reproductive phenology of the hosts. Peaks in relative mosquito feeding on each host during reproductive phases are likely the result of increased tolerance and decreased vigilance to attacking mosquitoes by nestlings and brooding adults (avian hosts, quiescent young (avian and mammalian hosts, and mate-seeking males (frogs.

  5. The effects of host-feeding on stability of discrete-time host-parasitoid population dynamic models.

    Science.gov (United States)

    Emerick, Brooks; Singh, Abhyudai

    2016-02-01

    Discrete-time models are the traditional approach for capturing population dynamics of a host-parasitoid system. Recent work has introduced a semi-discrete framework for obtaining model update functions that connect host-parasitoid population levels from year-to-year. In particular, this framework uses differential equations to describe the host-parasitoid interaction during the time of year when they come in contact, allowing specific behaviors to be mechanistically incorporated. We use the semi-discrete approach to study the effects of host-feeding, which occurs when a parasitoid consumes a potential host larva without ovipositing. We find that host-feeding by itself cannot stabilize the system, and both populations exhibit behavior similar to the Nicholson-Bailey model. However, when combined with stabilizing mechanisms such as density-dependent host mortality, host-feeding contracts the region of parameter space that allows for a stable host-parasitoid equilibrium. In contrast, when combined with a density-dependent parasitoid attack rate, host-feeding expands the non-zero equilibrium stability region. Our results show that host-feeding causes inefficiency in the parasitoid population, which yields a higher population of hosts per generation. This suggests that host-feeding may have limited long-term impact in terms of suppressing host levels for biological control applications. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Effectiveness of strict vs. multiple use protected areas in reducing tropical forest fires: a global analysis using matching methods.

    Directory of Open Access Journals (Sweden)

    Andrew Nelson

    Full Text Available Protected areas (PAs cover a quarter of the tropical forest estate. Yet there is debate over the effectiveness of PAs in reducing deforestation, especially when local people have rights to use the forest. A key analytic problem is the likely placement of PAs on marginal lands with low pressure for deforestation, biasing comparisons between protected and unprotected areas. Using matching techniques to control for this bias, this paper analyzes the global tropical forest biome using forest fires as a high resolution proxy for deforestation; disaggregates impacts by remoteness, a proxy for deforestation pressure; and compares strictly protected vs. multiple use PAs vs indigenous areas. Fire activity was overlaid on a 1 km map of tropical forest extent in 2000; land use change was inferred for any point experiencing one or more fires. Sampled points in pre-2000 PAs were matched with randomly selected never-protected points in the same country. Matching criteria included distance to road network, distance to major cities, elevation and slope, and rainfall. In Latin America and Asia, strict PAs substantially reduced fire incidence, but multi-use PAs were even more effective. In Latin America, where there is data on indigenous areas, these areas reduce forest fire incidence by 16 percentage points, over two and a half times as much as naïve (unmatched comparison with unprotected areas would suggest. In Africa, more recently established strict PAs appear to be effective, but multi-use tropical forest protected areas yield few sample points, and their impacts are not robustly estimated. These results suggest that forest protection can contribute both to biodiversity conservation and CO2 mitigation goals, with particular relevance to the REDD agenda. Encouragingly, indigenous areas and multi-use protected areas can help to accomplish these goals, suggesting some compatibility between global environmental goals and support for local livelihoods.

  7. Hydroxycinnamic acids used as external acceptors of electrons: an energetic advantage for strictly heterofermentative lactic acid bacteria.

    Science.gov (United States)

    Filannino, Pasquale; Gobbetti, Marco; De Angelis, Maria; Di Cagno, Raffaella

    2014-12-01

    The metabolism of hydroxycinnamic acids by strictly heterofermentative lactic acid bacteria (19 strains) was investigated as a potential alternative energy route. Lactobacillus curvatus PE5 was the most tolerant to hydroxycinnamic acids, followed by strains of Weissella spp., Lactobacillus brevis, Lactobacillus fermentum, and Leuconostoc mesenteroides, for which the MIC values were the same. The highest sensitivity was found for Lactobacillus rossiae strains. During growth in MRS broth, lactic acid bacteria reduced caffeic, p-coumaric, and ferulic acids into dihydrocaffeic, phloretic, and dihydroferulic acids, respectively, or decarboxylated hydroxycinnamic acids into the corresponding vinyl derivatives and then reduced the latter compounds to ethyl compounds. Reductase activities mainly emerged, and the activities of selected strains were further investigated in chemically defined basal medium (CDM) under anaerobic conditions. The end products of carbon metabolism were quantified, as were the levels of intracellular ATP and the NAD(+)/NADH ratio. Electron and carbon balances and theoretical ATP/glucose yields were also estimated. When CDM was supplemented with hydroxycinnamic acids, the synthesis of ethanol decreased and the concentration of acetic acid increased. The levels of these metabolites reflected on the alcohol dehydrogenase and acetate kinase activities. Overall, some biochemical traits distinguished the common metabolism of strictly heterofermentative strains: main reductase activity toward hydroxycinnamic acids, a shift from alcohol dehydrogenase to acetate kinase activities, an increase in the NAD(+)/NADH ratio, and the accumulation of supplementary intracellular ATP. Taken together, the above-described metabolic responses suggest that strictly heterofermentative lactic acid bacteria mainly use hydroxycinnamic acids as external acceptors of electrons. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  8. The host range of Phomopsis cirsii

    DEFF Research Database (Denmark)

    Leth, Vibeke; Andreasen, Christian

    2012-01-01

    . An isolate PKDK101 of the fungus Phomopsiscirsii, which is virulent to C. arvense causing stem canker and die back was chosen to test the specificity of the fungus. A series of infection trials were successively carried out on 127 plant species (incl. ssp. and var.) belonging to 16 families in greenhouses...... in order to encircle the host range of P. cirsii. Susceptible plant species were found only in the thistle group (Cardueae) which contained 34 species belonging to 12 genera. Susceptible species were found in thirteen of these genera. Highly susceptible species included Carduusacanthoides...... echinus, Cirsiumvulgare and Cynaracardunculusvar.scolymus (artichoke) with symptoms such as restricted necrotic leaf spots and too early senescence or death of entire leaf. Eleven hosts for P. cirsii were recorded but despite the expanded range of hosts we expect that its host range will be within...

  9. Diversifying selection and host adaptation in two endosymbiont genomes

    Directory of Open Access Journals (Sweden)

    Slatko Barton

    2007-04-01

    Full Text Available Abstract Background The endosymbiont Wolbachia pipientis infects a broad range of arthropod and filarial nematode hosts. These diverse associations form an attractive model for understanding host:symbiont coevolution. Wolbachia's ubiquity and ability to dramatically alter host reproductive biology also form the foundation of research strategies aimed at controlling insect pests and vector-borne disease. The Wolbachia strains that infect nematodes are phylogenetically distinct, strictly vertically transmitted, and required by their hosts for growth and reproduction. Insects in contrast form more fluid associations with Wolbachia. In these taxa, host populations are most often polymorphic for infection, horizontal transmission occurs between distantly related hosts, and direct fitness effects on hosts are mild. Despite extensive interest in the Wolbachia system for many years, relatively little is known about the molecular mechanisms that mediate its varied interactions with different hosts. We have compared the genomes of the Wolbachia that infect Drosophila melanogaster, wMel and the nematode Brugia malayi, wBm to that of an outgroup Anaplasma marginale to identify genes that have experienced diversifying selection in the Wolbachia lineages. The goal of the study was to identify likely molecular mechanisms of the symbiosis and to understand the nature of the diverse association across different hosts. Results The prevalence of selection was far greater in wMel than wBm. Genes contributing to DNA metabolism, cofactor biosynthesis, and secretion were positively selected in both lineages. In wMel there was a greater emphasis on DNA repair, cell division, protein stability, and cell envelope synthesis. Conclusion Secretion pathways and outer surface protein encoding genes are highly affected by selection in keeping with host:parasite theory. If evidence of selection on various cofactor molecules reflects possible provisioning, then both insect as

  10. Fermentative Degradation of Polyethylene Glycol by a Strictly Anaerobic, Gram-Negative, Nonsporeforming Bacterium, Pelobacter venetianus sp. nov

    OpenAIRE

    1983-01-01

    The synthetic polyether polyethylene glycol (PEG) with a molecular weight of 20,000 was anaerobically degraded in enrichment cultures inoculated with mud of limnic and marine origins. Three strains (Gra PEG 1, Gra PEG 2, and Ko PEG 2) of rod-shaped, gram-negative, nonsporeforming, strictly anaerobic bacteria were isolated in mineral medium with PEG as the sole source of carbon and energy. All strains degraded dimers, oligomers, and polymers of PEG up to a molecular weight of 20,000 completely...

  11. An Iterative Algorith