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Sample records for horizontal symbiont transmission

  1. Ephemeral windows of opportunity for horizontal transmission of fungal symbionts in leaf-cutting ants

    DEFF Research Database (Denmark)

    Poulsen, Michael; Fernández-Marín, Hermógenes; Currie, Cameron R.

    2009-01-01

    Evolutionary theory predicts that hosts are selected to prevent mixing of genetically different symbionts when competition among lineages reduces the productivity of a mutualism. The symbionts themselves may also defend their interests: recent studies of Acromyrmex leaf-cutting ants showed...... that somatic incompatibility enforces single-clone gardens within mature colonies, thereby constraining horizontal transmission of fungal symbionts. However, phylogenetic analyses indicate that symbiont switches occur frequently enough to remove most signs of host-symbiont cocladogenesis. Here we resolve...... this paradox by showing that transmission among newly founded Acromyrmex colonies is not constrained. All tested queens of sympatric A. octospinosus and A. echinatior offered a novel fragment of fungus garden accepted the new symbiont. The outcome was unaffected by genetic distance between the novel...

  2. Presumptive horizontal symbiont transmission in the fungus-growing termite Macrotermes natalensis

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Boomsma, Jacobus Jan; Aanen, Duur Kornelis

    2006-01-01

    All colonies of the fungus-growing termite Macrotermes natalensis studied so far are associated with a single genetically variable lineage of Termitomyces symbionts. Such limited genetic variation of symbionts and the absence of sexual fruiting bodies (mushrooms) on M. natalensis mounds would...... transmission mode among Macrotermes species implies that vertical symbiont transmission can evolve rapidly. The unexpected finding of horizontal transmission makes the apparent absence of Termitomyces mushrooms on M. natalensis mounds puzzling. To our knowledge, this is the first detailed study of the genetic...

  3. Plant-mediated interspecific horizontal transmission of an intracellular symbiont in insects

    KAUST Repository

    Gonella, Elena

    2015-11-13

    Intracellular reproductive manipulators, such as Candidatus Cardinium and Wolbachia are vertically transmitted to progeny but rarely show co-speciation with the host. In sap-feeding insects, plant tissues have been proposed as alternative horizontal routes of interspecific transmission, but experimental evidence is limited. Here we report results from experiments that show that Cardinium is horizontally transmitted between different phloem sap-feeding insect species through plants. Quantitative PCR and in situ hybridization experiments indicated that the leafhopper Scaphoideus titanus releases Cardinium from its salivary glands during feeding on both artificial media and grapevine leaves. Successional time-course feeding experiments with S. titanus initially fed sugar solutions or small areas of grapevine leaves followed by feeding by the phytoplasma vector Macrosteles quadripunctulatus or the grapevine feeder Empoasca vitis revealed that the symbionts were transmitted to both species. Explaining interspecific horizontal transmission through plants improves our understanding of how symbionts spread, their lifestyle and the symbiont-host intermixed evolutionary pattern.

  4. Presumptive horizontal symbiont transmission in the fungus-growing termite Macrotermes natalensis

    NARCIS (Netherlands)

    Fine Licht, de H.H.; Boomsma, J.J.; Aanen, D.K.

    2006-01-01

    All colonies of the fungus-growing termite Macrotermes natalensis studied so far are associated with a single genetically variable lineage of Termitomyces symbionts. Such limited genetic variation of symbionts and the absence of sexual fruiting bodies (mushrooms) on M. natalensis mounds would be com

  5. Tracking transmission of apicomplexan symbionts in diverse Caribbean corals.

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    Nathan L Kirk

    Full Text Available Symbionts in each generation are transmitted to new host individuals either vertically (parent to offspring, horizontally (from exogenous sources, or a combination of both. Scleractinian corals make an excellent study system for understanding patterns of symbiont transmission since they harbor diverse symbionts and possess distinct reproductive modes of either internal brooding or external broadcast spawning that generally correlate with vertical or horizontal transmission, respectively. Here, we focused on the under-recognized, but apparently widespread, coral-associated apicomplexans (Protista: Alveolata to determine if symbiont transmission depends on host reproductive mode. Specifically, a PCR-based assay was utilized towards identifying whether planula larvae and reproductive adults from brooding and broadcast spawning scleractinian coral species in Florida and Belize harbored apicomplexan DNA. Nearly all (85.5%; n = 85/89 examined planulae of five brooding species (Porites astreoides, Agaricia tenuifolia, Agaricia agaricites, Favia fragum, Mycetophyllia ferox and adults of P. astreoides were positive for apicomplexan DNA. In contrast, no (n = 0/10 apicomplexan DNA was detected from planulae of four broadcast spawning species (Acropora cervicornis, Acropora palmata, Pseudodiploria strigosa, and Orbicella faveolata and rarely in gametes (8.9%; n = 5/56 of these species sampled from the same geographical range as the brooding species. In contrast, tissue samples from nearly all (92.0%; n = 81/88 adults of the broadcast spawning species A. cervicornis, A. palmata and O. faveolata harbored apicomplexan DNA, including colonies whose gametes and planulae tested negative for these symbionts. Taken together, these data suggest apicomplexans are transmitted vertically in these brooding scleractinian coral species while the broadcast spawning scleractinian species examined here acquire these symbionts horizontally. Notably, these transmission

  6. Tracking Transmission of Apicomplexan Symbionts in Diverse Caribbean Corals

    Science.gov (United States)

    Kirk, Nathan L.; Ritson-Williams, Raphael; Coffroth, Mary Alice; Miller, Margaret W.; Fogarty, Nicole D.; Santos, Scott R.

    2013-01-01

    Symbionts in each generation are transmitted to new host individuals either vertically (parent to offspring), horizontally (from exogenous sources), or a combination of both. Scleractinian corals make an excellent study system for understanding patterns of symbiont transmission since they harbor diverse symbionts and possess distinct reproductive modes of either internal brooding or external broadcast spawning that generally correlate with vertical or horizontal transmission, respectively. Here, we focused on the under-recognized, but apparently widespread, coral-associated apicomplexans (Protista: Alveolata) to determine if symbiont transmission depends on host reproductive mode. Specifically, a PCR-based assay was utilized towards identifying whether planula larvae and reproductive adults from brooding and broadcast spawning scleractinian coral species in Florida and Belize harbored apicomplexan DNA. Nearly all (85.5%; n = 85/89) examined planulae of five brooding species (Porites astreoides, Agaricia tenuifolia, Agaricia agaricites, Favia fragum, Mycetophyllia ferox) and adults of P. astreoides were positive for apicomplexan DNA. In contrast, no (n = 0/10) apicomplexan DNA was detected from planulae of four broadcast spawning species (Acropora cervicornis, Acropora palmata, Pseudodiploria strigosa, and Orbicella faveolata) and rarely in gametes (8.9%; n = 5/56) of these species sampled from the same geographical range as the brooding species. In contrast, tissue samples from nearly all (92.0%; n = 81/88) adults of the broadcast spawning species A. cervicornis, A. palmata and O. faveolata harbored apicomplexan DNA, including colonies whose gametes and planulae tested negative for these symbionts. Taken together, these data suggest apicomplexans are transmitted vertically in these brooding scleractinian coral species while the broadcast spawning scleractinian species examined here acquire these symbionts horizontally. Notably, these transmission patterns are

  7. Tracking transmission of apicomplexan symbionts in diverse Caribbean corals.

    Science.gov (United States)

    Kirk, Nathan L; Ritson-Williams, Raphael; Coffroth, Mary Alice; Miller, Margaret W; Fogarty, Nicole D; Santos, Scott R

    2013-01-01

    Symbionts in each generation are transmitted to new host individuals either vertically (parent to offspring), horizontally (from exogenous sources), or a combination of both. Scleractinian corals make an excellent study system for understanding patterns of symbiont transmission since they harbor diverse symbionts and possess distinct reproductive modes of either internal brooding or external broadcast spawning that generally correlate with vertical or horizontal transmission, respectively. Here, we focused on the under-recognized, but apparently widespread, coral-associated apicomplexans (Protista: Alveolata) to determine if symbiont transmission depends on host reproductive mode. Specifically, a PCR-based assay was utilized towards identifying whether planula larvae and reproductive adults from brooding and broadcast spawning scleractinian coral species in Florida and Belize harbored apicomplexan DNA. Nearly all (85.5%; n = 85/89) examined planulae of five brooding species (Porites astreoides, Agaricia tenuifolia, Agaricia agaricites, Favia fragum, Mycetophyllia ferox) and adults of P. astreoides were positive for apicomplexan DNA. In contrast, no (n = 0/10) apicomplexan DNA was detected from planulae of four broadcast spawning species (Acropora cervicornis, Acropora palmata, Pseudodiploria strigosa, and Orbicella faveolata) and rarely in gametes (8.9%; n = 5/56) of these species sampled from the same geographical range as the brooding species. In contrast, tissue samples from nearly all (92.0%; n = 81/88) adults of the broadcast spawning species A. cervicornis, A. palmata and O. faveolata harbored apicomplexan DNA, including colonies whose gametes and planulae tested negative for these symbionts. Taken together, these data suggest apicomplexans are transmitted vertically in these brooding scleractinian coral species while the broadcast spawning scleractinian species examined here acquire these symbionts horizontally. Notably, these transmission patterns are

  8. Almost there: transmission routes of bacterial symbionts between trophic levels.

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    Elad Chiel

    Full Text Available Many intracellular microbial symbionts of arthropods are strictly vertically transmitted and manipulate their host's reproduction in ways that enhance their own transmission. Rare horizontal transmission events are nonetheless necessary for symbiont spread to novel host lineages. Horizontal transmission has been mostly inferred from phylogenetic studies but the mechanisms of spread are still largely a mystery. Here, we investigated transmission of two distantly related bacterial symbionts--Rickettsia and Hamiltonella--from their host, the sweet potato whitefly, Bemisia tabaci, to three species of whitefly parasitoids: Eretmocerus emiratus, Eretmocerus eremicus and Encarsia pergandiella. We also examined the potential for vertical transmission of these whitefly symbionts between parasitoid generations. Using florescence in situ hybridization (FISH and transmission electron microscopy we found that Rickettsia invades Eretmocerus larvae during development in a Rickettsia-infected host, persists in adults and in females, reaches the ovaries. However, Rickettsia does not appear to penetrate the oocytes, but instead is localized in the follicular epithelial cells only. Consequently, Rickettsia is not vertically transmitted in Eretmocerus wasps, a result supported by diagnostic polymerase chain reaction (PCR. In contrast, Rickettsia proved to be merely transient in the digestive tract of Encarsia and was excreted with the meconia before wasp pupation. Adults of all three parasitoid species frequently acquired Rickettsia via contact with infected whiteflies, most likely by feeding on the host hemolymph (host feeding, but the rate of infection declined sharply within a few days of wasps being removed from infected whiteflies. In contrast with Rickettsia, Hamiltonella did not establish in any of the parasitoids tested, and none of the parasitoids acquired Hamiltonella by host feeding. This study demonstrates potential routes and barriers to horizontal

  9. Diverse strategies for vertical symbiont transmission among subsocial stinkbugs.

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    Takahiro Hosokawa

    Full Text Available Sociality may affect symbiosis and vice versa. Many plant-sucking stinkbugs harbor mutualistic bacterial symbionts in the midgut. In the superfamily Pentatomoidea, adult females excrete symbiont-containing materials from the anus, which their offspring ingest orally and establish vertical symbiont transmission. In many stinkbug families whose members are mostly non-social, females excrete symbiont-containing materials onto/beside eggs upon oviposition. However, exceptional cases have been reported from two subsocial species representing the closely related families Cydnidae and Parastrachiidae, wherein females remain nearby eggs for maternal care after oviposition, and provide their offspring with symbiont-containing secretions at later stages, either just before or after hatching. These observations suggested that sociality of the host stinkbugs may be correlated with their symbiont transmission strategies. However, we found that cydnid stinkbugs of the genus Adomerus, which are associated with gammaproteobacterial gut symbionts and exhibit elaborate maternal care over their offspring, smear symbiont-containing secretions onto eggs upon oviposition as many non-social stinkbugs do. Surface sterilization of the eggs resulted in aposymbiotic insects of slower growth, smaller size and abnormal body coloration, indicating vertical symbiont transmission via egg surface contamination and presumable beneficial nature of the symbiosis. The Adomerus symbionts exhibited AT-biased nucleotide compositions, accelerated molecular evolutionary rates and reduced genome size, while these degenerative genomic traits were less severe than those in the symbiont of a subsocial parastrachiid. These results suggest that not only sociality but also other ecological and evolutionary aspects of the host stinkbugs, including the host-symbiont co-evolutionary history, may have substantially affected their symbiont transmission strategies.

  10. Negative fitness consequences and transmission dynamics of a heritable fungal symbiont of a parasitic wasp.

    Science.gov (United States)

    Gibson, Cara M; Hunter, Martha S

    2009-05-01

    Heritable bacterial symbionts are widespread in insects and can have many important effects on host ecology and fitness. Fungal symbionts are also important in shaping their hosts' behavior, interactions, and evolution, but they have been largely overlooked. Experimental tests to determine the relevance of fungal symbionts to their insect hosts are currently extremely rare, and to our knowledge, there have been no such tests for strictly predacious insects. We investigated the fitness consequences for a parasitic wasp (Comperia merceti) of an inherited fungal symbiont in the Saccharomycotina (Ascomycota) that was long presumed to be a mutualist. In comparisons of wasp lines with and without this symbiont, we found no evidence of mutualism. Instead, there were significant fitness costs to the wasps in the presence of the yeast; infected wasps attacked fewer hosts and had longer development times. We also examined the relative competitive abilities of the larval progeny of infected and uninfected mothers, as well as horizontal transmission of the fungal symbiont among larval wasps that shared a single host cockroach egg case. We found no difference in larval competitive ability when larvae whose infection status differed shared a single host. We did find high rates of horizontal transmission of the fungus, and we suggest that this transmission is likely responsible for the maintenance of this infection in wasp populations.

  11. Multiple symbiont acquisition strategies as an adaptive mechanism in the coral Stylophora pistillata.

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    Byler, Kristen A; Carmi-Veal, Maya; Fine, Maoz; Goulet, Tamar L

    2013-01-01

    In obligate symbioses, the host's survival relies on the successful acquisition and maintenance of symbionts. Symbionts can either be transferred from parent to offspring via direct inheritance (vertical transmission) or acquired anew each generation from the environment (horizontal transmission). With vertical symbiont transmission, progeny benefit by not having to search for their obligate symbionts, and, with symbiont inheritance, a mechanism exists for perpetuating advantageous symbionts. But, if the progeny encounter an environment that differs from that of their parent, they may be disadvantaged if the inherited symbionts prove suboptimal. Conversely, while in horizontal symbiont acquisition host survival hinges on an unpredictable symbiont source, an individual host may acquire genetically diverse symbionts well suited to any given environment. In horizontal acquisition, however, a potentially advantageous symbiont will not be transmitted to subsequent generations. Adaptation in obligate symbioses may require mechanisms for both novel symbiont acquisition and symbiont inheritance. Using denaturing-gradient gel electrophoresis and real-time PCR, we identified the dinoflagellate symbionts (genus Symbiodinium) hosted by the Red Sea coral Stylophora pistillata throughout its ontogenesis and over depth. We present evidence that S. pistillata juvenile colonies may utilize both vertical and horizontal symbiont acquisition strategies. By releasing progeny with maternally derived symbionts, that are also capable of subsequent horizontal symbiont acquisition, coral colonies may acquire physiologically advantageous novel symbionts that are then perpetuated via vertical transmission to subsequent generations. With symbiont inheritance, natural selection can act upon the symbiotic variability, providing a mechanism for coral adaptation.

  12. Multiple symbiont acquisition strategies as an adaptive mechanism in the coral Stylophora pistillata.

    Directory of Open Access Journals (Sweden)

    Kristen A Byler

    Full Text Available In obligate symbioses, the host's survival relies on the successful acquisition and maintenance of symbionts. Symbionts can either be transferred from parent to offspring via direct inheritance (vertical transmission or acquired anew each generation from the environment (horizontal transmission. With vertical symbiont transmission, progeny benefit by not having to search for their obligate symbionts, and, with symbiont inheritance, a mechanism exists for perpetuating advantageous symbionts. But, if the progeny encounter an environment that differs from that of their parent, they may be disadvantaged if the inherited symbionts prove suboptimal. Conversely, while in horizontal symbiont acquisition host survival hinges on an unpredictable symbiont source, an individual host may acquire genetically diverse symbionts well suited to any given environment. In horizontal acquisition, however, a potentially advantageous symbiont will not be transmitted to subsequent generations. Adaptation in obligate symbioses may require mechanisms for both novel symbiont acquisition and symbiont inheritance. Using denaturing-gradient gel electrophoresis and real-time PCR, we identified the dinoflagellate symbionts (genus Symbiodinium hosted by the Red Sea coral Stylophora pistillata throughout its ontogenesis and over depth. We present evidence that S. pistillata juvenile colonies may utilize both vertical and horizontal symbiont acquisition strategies. By releasing progeny with maternally derived symbionts, that are also capable of subsequent horizontal symbiont acquisition, coral colonies may acquire physiologically advantageous novel symbionts that are then perpetuated via vertical transmission to subsequent generations. With symbiont inheritance, natural selection can act upon the symbiotic variability, providing a mechanism for coral adaptation.

  13. Vertical transmission of chemoautotrophic symbionts in the bivalve Solemya velum (Bivalvia: Protobranchia).

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    Krueger, D M; Gustafson, R G; Cavanaugh, C M

    1996-04-01

    Adults of the bivalve species Solemya velum live in symbiosis with chemoautotrophic bacteria in specialized gill bacteriocytes. The bacteria play an essential nutritional role in the mature association, fixing CO2 via the Calvin cycle with energy obtained through the oxidation of reduced sulfur compounds. To understand how the continuity of this partnership is maintained between host generations, we investigated the mode of symbiont transfer in S. velum. A diagnostic assay using the polymerase chain reaction and primers specific for the S. velum symbiont ribulose-1,5-bisphosphate carboxylase (RubisCO) gene consistently detected bacterial sequence in female gonad tissue, suggesting the presence of symbiont cells in host ovaries and a vertical mode of symbiont transmission from mother to offspring. Furthermore, intracellular bacteria were present in the developing gills of juveniles that had not yet hatched from the gelatinous capsule in which larval development occurs (11 days after fertilization). By 64 days postfertilization, the typical adult gill ultrastructure of alternating bacteriocytes and symbiont-free-intercalary cells was apparent. Knowledge about the mode of symbiont transfer in S. velum allows further study into the dynamics of host-symbiont interactions in chemoautotrophic associations.

  14. Does horizontal transmission invalidate cultural phylogenies?

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    Greenhill, Simon J; Currie, Thomas E; Gray, Russell D

    2009-06-22

    Phylogenetic methods have recently been applied to studies of cultural evolution. However, it has been claimed that the large amount of horizontal transmission that sometimes occurs between cultural groups invalidates the use of these methods. Here, we use a natural model of linguistic evolution to simulate borrowing between languages. The results show that tree topologies constructed with Bayesian phylogenetic methods are robust to realistic levels of borrowing. Inferences about divergence dates are slightly less robust and show a tendency to underestimate dates. Our results demonstrate that realistic levels of reticulation between cultures do not invalidate a phylogenetic approach to cultural and linguistic evolution.

  15. Horizontal versus familial transmission of Helicobacter pylori.

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    Sandra Schwarz

    2008-10-01

    Full Text Available Transmission of Helicobacter pylori is thought to occur mainly during childhood, and predominantly within families. However, due to the difficulty of obtaining H. pylori isolates from large population samples and to the extensive genetic diversity between isolates, the transmission and spread of H. pylori remain poorly understood. We studied the genetic relationships of H. pylori isolated from 52 individuals of two large families living in a rural community in South Africa and from 43 individuals of 11 families living in urban settings in the United Kingdom, the United States, Korea, and Colombia. A 3,406 bp multilocus sequence haplotype was determined for a total of 142 H. pylori isolates. Isolates were assigned to biogeographic populations, and recent transmission was measured as the occurrence of non-unique isolates, i.e., isolates whose sequences were identical to those of other isolates. Members of urban families were almost always infected with isolates from the biogeographic population that is common in their location. Non-unique isolates were frequent in urban families, consistent with familial transmission between parents and children or between siblings. In contrast, the diversity of H. pylori in the South African families was much more extensive, and four distinct biogeographic populations circulated in this area. Non-unique isolates were less frequent in South African families, and there was no significant correlation between kinship and similarity of H. pylori sequences. However, individuals who lived in the same household did have an increased probability of carrying the same non-unique isolates of H. pylori, independent of kinship. We conclude that patterns of spread of H. pylori under conditions of high prevalence, such as the rural South African families, differ from those in developed countries. Horizontal transmission occurs frequently between persons who do not belong to a core family, blurring the pattern of familial

  16. Insect symbiont facilitates vector acquisition, retention, and transmission of plant virus

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    Su, Qi; Pan, Huipeng; Liu, Baiming; Chu, Dong; Xie, Wen; Wu, Qingjun; Wang, Shaoli; Xu, Baoyun; Zhang, Youjun

    2013-01-01

    Tomato yellow leaf curl virus (TYLCV) was first detected in China in 2006, following the introduction of Bemisia tabaci Q into China in 2003. Since then, the incidence of TYLCV in tomato fields in China has greatly increased as has the abundance and distribution of Q whiteflies containing the bacterial symbiont Hamiltonella with high frequency. This suggested that the symbiont Hamiltonella might associate with the transmission efficiency of TYLCV by the whitefly vector. Here we report the first evidence that the Hamiltonella is closely associated with the acquisition, retention, and transmission efficiency of TYLCV by the whitefly vector. Our findings combined with the outbreaks of TYLCV following the introduction of Q, provided an explanation for why Hamiltonella is being maintained at a relatively high level in Chinese B. tabaci Q and also have implications for disease and vector management. PMID:23455639

  17. Bacterial symbionts in the hepatopancreas of isopods: diversity and environmental transmission.

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    Wang, Yongjie; Brune, Andreas; Zimmer, Martin

    2007-07-01

    The midgut glands (hepatopancreas) of terrestrial isopods contain bacterial symbionts. We analysed the phylogenetic diversity of hepatopancreatic bacteria in isopod species from various suborders colonizing marine, semiterrestrial, terrestrial and freshwater habitats. Hepatopancreatic bacteria were absent in the marine isopod Idotea balthica (Valvifera). The symbiotic bacteria present in the midgut glands of the freshwater isopod Asellus aquaticus (Asellota) were closely related to members of the proteobacterial genera Rhodobacter, Burkholderia, Aeromonas or Rickettsiella, but differed markedly between populations. By contrast, species of the suborder Oniscidea were consistently colonized by the same phylotypes of hepatopancreatic bacteria. While symbionts in the semiterrestrial isopod Ligia oceanica (Oniscidea) were close relatives of Pseudomonas sp. (Gammaproteobacteria), individuals of the terrestrial isopod Oniscus asellus (Oniscidea) harboured either 'Candidatus Hepatoplasma crinochetorum' (Mollicutes) or 'Candidatus Hepatincola porcellionum' (Rickettsiales), previously described as symbionts of another terrestrial isopod, Porcellio scaber. These two uncultivated bacterial taxa were consistently present in each population of six and three different species of terrestrial isopods, respectively, collected in different geographical locations. However, infection rates of individuals within a population ranged between 10% and 100%, rendering vertical transmission unlikely. Rather, feeding experiments suggest that 'Candidatus Hepatoplasma crinochetorum' is environmentally transmitted to the progeny.

  18. Should sex-ratio distorting parasites abandon horizontal transmission?

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    Ironside Joseph E

    2011-12-01

    Full Text Available Abstract Background Sex-ratio distorting parasites are of interest due to their effects upon host population dynamics and their potential to influence the evolution of host sex determination systems. In theory, the ability to distort host sex-ratios allows a parasite with efficient vertical (hereditary transmission to dispense completely with horizontal (infectious transmission. However, recent empirical studies indicate that some sex-ratio distorting parasites have retained the capability for horizontal transmission. Results Numerical simulations using biologically realistic parameters suggest that a feminising parasite is only likely to lose the capability for horizontal transmission if its host occurs at low density and/or has a male-biased primary sex ratio. It is also demonstrated that even a small amount of horizontal transmission can allow multiple feminising parasites to coexist within a single host population. Finally it is shown that, by boosting its host's rate of population growth, a feminising parasite can increase its own horizontal transmission and allow the invasion of other, more virulent parasites. Conclusions The prediction that sex-ratio distorting parasites are likely to retain a degree of horizontal transmission has important implications for the epidemiology and host-parasite interactions of these organisms. It may also explain the frequent co-occurrence of several sex-ratio distorting parasite species in nature.

  19. Horizontal gene transfer of a bacterial insect toxin gene into the Epichloë fungal symbionts of grasses

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    Ambrose, Karen V.; Koppenhöfer, Albrecht M.; Belanger, Faith C.

    2014-01-01

    Horizontal gene transfer is recognized as an important factor in genome evolution, particularly when the newly acquired gene confers a new capability to the recipient species. We identified a gene similar to the makes caterpillars floppy (mcf1 and mcf2) insect toxin genes in Photorhabdus, bacterial symbionts of nematodes, in the genomes of the Epichloë fungi, which are intercellular symbionts of grasses. Infection by Epichloë spp. often confers insect resistance to the grass hosts, largely due to the production of fungal alkaloids. A mcf-like gene is present in all of the Epichloë genome sequences currently available but in no other fungal genomes. This suggests the Epichloë genes were derived from a single lineage-specific HGT event. Molecular dating was used to estimate the time of the HGT event at between 7.2 and 58.8 million years ago. The mcf-like coding sequence from Epichloë typhina subsp. poae was cloned and expressed in Escherichia coli. E. coli cells expressing the Mcf protein were toxic to black cutworms (Agrotis ipsilon), whereas E. coli cells containing the vector only were non-toxic. These results suggest that the Epichloë mcf-like genes may be a component, in addition to the fungal alkaloids, of the insect resistance observed in Epichloë-infected grasses. PMID:24990771

  20. Farming termites determine the genetic population structure of Termitomyces fungal symbionts

    DEFF Research Database (Denmark)

    Nobre, Tânia; Fernandes, Cecília; Boomsma, Jacobus J

    2011-01-01

    fungal symbionts. However, even in the few termite lineages that secondarily adopted vertical symbiont transmission, the fungal symbionts are not monophyletic. We addressed this paradox by studying differential transmission of fungal symbionts by alate male and female reproductives, and the genetic......Symbiotic interactions between macrotermitine termites and their fungal symbionts have a moderate degree of specificity. Consistent with horizontal symbiont transmission, host switching has been frequent over evolutionary time so that single termite species can often be associated with several...... associated with the alternative termite hosts Macrotermes subhyalinus and Macrotermes natalensis. While Termitomyces associated with these alternative hosts are horizontally transmitted and recombine freely, the genetic population structure of the same Termitomyces associated with M. bellicosus is consistent...

  1. EPICHLOE SPECIES: fungal symbionts of grasses.

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    Schardl, C L

    1996-01-01

    Epichloë species and their asexual descendants (Acremonium endophytes) are fungal symbionts of C3 grasses that span the symbiotic continuum from antagonism to mutualism depending on the relative importance, respectively, of horizontal transmission of sexual spores versus vertical clonal transmission in healthy grass seeds. At least seven sexual Epichloë species are identifiable by mating tests, and many asexual genotypes are interspecific hybrids. Benefits conferred by the symbionts on host plants include protection from biotic factors and abiotic stresses such as drought. Four classes of beneficial alkaloids are associated with the symbionts: ergot alkaloids, indolediterpenes (lolitrems), peramine, and saturated aminopyrrolizidines (lolines). These alkaloids protect host plants from insect and vertebrate herbivores, including livestock. Genetic engineering of the fungal symbionts as more suitable biological protectants for forage grasses requires identification of fungal genes for alkaloid biosynthesis, and DNA-mediated transformation of the fungi.

  2. Et tu, Brute? Not Even Intracellular Mutualistic Symbionts Escape Horizontal Gene Transfer

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    Sergio López-Madrigal

    2017-09-01

    Full Text Available Many insect species maintain mutualistic relationships with endosymbiotic bacteria. In contrast to their free-living relatives, horizontal gene transfer (HGT has traditionally been considered rare in long-term endosymbionts. Nevertheless, meta-omics exploration of certain symbiotic models has unveiled an increasing number of bacteria-bacteria and bacteria-host genetic transfers. The abundance and function of transferred loci suggest that HGT might play a major role in the evolution of the corresponding consortia, enhancing their adaptive value or buffering detrimental effects derived from the reductive evolution of endosymbionts’ genomes. Here, we comprehensively review the HGT cases recorded to date in insect-bacteria mutualistic consortia, and discuss their impact on the evolutionary success of these associations.

  3. Birth of a W sex chromosome by horizontal transfer of Wolbachia bacterial symbiont genome

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    Leclercq, Sébastien; Thézé, Julien; Chebbi, Mohamed Amine; Giraud, Isabelle; Moumen, Bouziane; Ernenwein, Lise; Grève, Pierre; Cordaux, Richard

    2016-01-01

    Sex determination is a fundamental developmental pathway governing male and female differentiation, with profound implications for morphology, reproductive strategies, and behavior. In animals, sex differences between males and females are generally determined by genetic factors carried by sex chromosomes. Sex chromosomes are remarkably variable in origin and can differ even between closely related species, indicating that transitions occur frequently and independently in different groups of organisms. The evolutionary causes underlying sex chromosome turnover are poorly understood, however. Here we provide evidence indicating that Wolbachia bacterial endosymbionts triggered the evolution of new sex chromosomes in the common pillbug Armadillidium vulgare. We identified a 3-Mb insert of a feminizing Wolbachia genome that was recently transferred into the pillbug nuclear genome. The Wolbachia insert shows perfect linkage to the female sex, occurs in a male genetic background (i.e., lacking the ancestral W female sex chromosome), and is hemizygous. Our results support the conclusion that the Wolbachia insert is now acting as a female sex-determining region in pillbugs, and that the chromosome carrying the insert is a new W sex chromosome. Thus, bacteria-to-animal horizontal genome transfer represents a remarkable mechanism underpinning the birth of sex chromosomes. We conclude that sex ratio distorters, such as Wolbachia endosymbionts, can be powerful agents of evolutionary transitions in sex determination systems in animals. PMID:27930295

  4. Evidence for a symbiosis island involved in horizontal acquisition of pederin biosynthetic capabilities by the bacterial symbiont of Paederus fuscipes beetles.

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    Piel, Jörn; Höfer, Ivonne; Hui, Dequan

    2004-03-01

    Pederin belongs to a group of antitumor compounds found in terrestrial beetles and marine sponges. It is used by apparently all members of the rove beetle genera Paederus and Paederidus as a chemical defense against predators. However, a recent analysis of the putative pederin biosynthesis (ped) gene cluster strongly suggests that pederin is produced by bacterial symbionts. We have sequenced an extended region of the symbiont genome to gain further insight into the biology of this as-yet-unculturable bacterium and the evolution of pederin symbiosis. Our data indicate that the symbiont is a very close relative of Pseudomonas aeruginosa that has acquired several foreign genetic elements by horizontal gene transfer. Besides one functional tellurite resistance operon, the region contains a genomic island spanning 71.6 kb that harbors the putative pederin biosynthetic genes. Several decayed insertion sequence elements and the mosaic-like appearance of the island suggest that the acquisition of the ped symbiosis genes was followed by further insertions and rearrangements. A horizontal transfer of genes for the biosynthesis of protective substances could explain the widespread occurrence of pederin-type compounds in unrelated animals from diverse habitats.

  5. Farming termites determine the genetic population structure of Termitomyces fungal symbionts.

    Science.gov (United States)

    Nobre, Tânia; Fernandes, Cecília; Boomsma, Jacobus J; Korb, Judith; Aanen, Duur K

    2011-05-01

    Symbiotic interactions between macrotermitine termites and their fungal symbionts have a moderate degree of specificity. Consistent with horizontal symbiont transmission, host switching has been frequent over evolutionary time so that single termite species can often be associated with several fungal symbionts. However, even in the few termite lineages that secondarily adopted vertical symbiont transmission, the fungal symbionts are not monophyletic. We addressed this paradox by studying differential transmission of fungal symbionts by alate male and female reproductives, and the genetic population structure of Termitomyces fungus gardens across 74 colonies of Macrotermes bellicosus in four west and central African countries. We confirm earlier, more limited, studies showing that the Termitomyces symbionts of M. bellicosus are normally transmitted vertically and clonally by dispersing males. We also document that the symbionts associated with this termite species belong to three main lineages that do not constitute a monophyletic group. The most common lineage occurs over the entire geographical region that we studied, including west, central and southern Africa, where it is also associated with the alternative termite hosts Macrotermes subhyalinus and Macrotermes natalensis. While Termitomyces associated with these alternative hosts are horizontally transmitted and recombine freely, the genetic population structure of the same Termitomyces associated with M. bellicosus is consistent with predominantly clonal reproduction and only occasional recombination. This implies that the genetic population structure of Termitomyces is controlled by the termite host and not by the Termitomyces symbiont.

  6. Superparasitism Drives Heritable Symbiont Epidemiology and Host Sex Ratio in a Wasp.

    Directory of Open Access Journals (Sweden)

    Steven R Parratt

    2016-06-01

    Full Text Available Heritable microbial symbionts have profound impacts upon the biology of their arthropod hosts. Whilst our current understanding of the dynamics of these symbionts is typically cast within a framework of vertical transmission only, horizontal transmission has been observed in a number of cases. For instance, several symbionts can transmit horizontally when their parasitoid hosts share oviposition patches with uninfected conspecifics, a phenomenon called superparasitism. Despite this, horizontal transmission, and the host contact structures that facilitates it, have not been considered in heritable symbiont epidemiology. Here, we tested for the importance of host contact, and resulting horizontal transmission, for the epidemiology of a male-killing heritable symbiont (Arsenophonus nasoniae in parasitoid wasp hosts. We observed that host contact through superparasitism is necessary for this symbiont's spread in populations of its primary host Nasonia vitripennis, such that when superparasitism rates are high, A. nasoniae almost reaches fixation, causes highly female biased population sex ratios and consequently causes local host extinction. We further tested if natural interspecific variation in superparasitism behaviours predicted symbiont dynamics among parasitoid species. We found that A. nasoniae was maintained in laboratory populations of a closely related set of Nasonia species, but declined in other, more distantly related pteromalid hosts. The natural proclivity of a species to superparasitise was the primary factor determining symbiont persistence. Our results thus indicate that host contact behaviour is a key factor for heritable microbe dynamics when horizontal transmission is possible, and that 'reproductive parasite' phenotypes, such as male-killing, may be of secondary importance in the dynamics of such symbiont infections.

  7. Superparasitism Drives Heritable Symbiont Epidemiology and Host Sex Ratio in a Wasp.

    Directory of Open Access Journals (Sweden)

    Steven R Parratt

    2016-06-01

    Full Text Available Heritable microbial symbionts have profound impacts upon the biology of their arthropod hosts. Whilst our current understanding of the dynamics of these symbionts is typically cast within a framework of vertical transmission only, horizontal transmission has been observed in a number of cases. For instance, several symbionts can transmit horizontally when their parasitoid hosts share oviposition patches with uninfected conspecifics, a phenomenon called superparasitism. Despite this, horizontal transmission, and the host contact structures that facilitates it, have not been considered in heritable symbiont epidemiology. Here, we tested for the importance of host contact, and resulting horizontal transmission, for the epidemiology of a male-killing heritable symbiont (Arsenophonus nasoniae in parasitoid wasp hosts. We observed that host contact through superparasitism is necessary for this symbiont's spread in populations of its primary host Nasonia vitripennis, such that when superparasitism rates are high, A. nasoniae almost reaches fixation, causes highly female biased population sex ratios and consequently causes local host extinction. We further tested if natural interspecific variation in superparasitism behaviours predicted symbiont dynamics among parasitoid species. We found that A. nasoniae was maintained in laboratory populations of a closely related set of Nasonia species, but declined in other, more distantly related pteromalid hosts. The natural proclivity of a species to superparasitise was the primary factor determining symbiont persistence. Our results thus indicate that host contact behaviour is a key factor for heritable microbe dynamics when horizontal transmission is possible, and that 'reproductive parasite' phenotypes, such as male-killing, may be of secondary importance in the dynamics of such symbiont infections.

  8. Horizontal transmission of Symbiodinium cells between adult and juvenile corals is aided by benthic sediment

    Science.gov (United States)

    Nitschke, Matthew R.; Davy, Simon K.; Ward, Selina

    2016-03-01

    Of all reef-building coral species, 80-85 % initially draw their intracellular symbionts (dinoflagellates of the genus Symbiodinium) from the environment. Although Symbiodinium cells are crucial for the growth of corals and the formation of coral reefs, little is known about how corals first encounter free-living Symbiodinium cells. We report how the supply of free-living Symbiodinium cells to the benthos by adult corals can increase the rate of horizontal symbiont acquisition for conspecific recruits. Three species of newly settled aposymbiotic (i.e., symbiont-free) corals were maintained in an open aquarium system containing: sterilized sediment and adult coral fragments combined; adult coral fragments alone; sterilized sediment alone; or seawater at Heron Island, Great Barrier Reef, Australia. In all instances, the combination of an adult coral and sediment resulted in the highest symbiont acquisition rates by juvenile corals (up to five-fold greater than seawater alone). Juvenile corals exposed to individual treatments of adult coral or sediment produced an intermediate acquisition response (<52 % of recruits), and symbiont acquisition from unfiltered seawater was comparatively low (<20 % of recruits). Additionally, benthic free-living Symbiodinium cells reached their highest densities in the adult coral + sediment treatment (up to 1.2 × 104 cells mL-1). Our results suggest that corals seed microhabitats with free-living Symbiodinium cells suitable for many coral species during the process of coral recruitment.

  9. Exploring symbiont management in lichens.

    Science.gov (United States)

    Grube, Martin; Spribille, Toby

    2012-07-01

    Lichens are unique among fungal symbioses in that their mycelial structures are compact and exposed to the light as thallus structures. The myriad intersections of unique fungal species with photosynthetic partner organisms (green algae in 90% of lichens) produce a wide variety of diverse shapes and colours of the fully synthesized lichen thallus when growing in nature. This characteristic complex morphology is, however, not achieved in the fungal axenic state. Even under ideal environmental conditions, the lichen life cycle faces considerable odds: first, meiotic spores are only produced on well-established thalli and often only after achieving considerable age in a stable environment, and second, even then in vivo resynthesis requires the presence of compatible algal strains where fungal spores germinate. Many lichen species have evolved a way around the resynthesis bottleneck by producing asexual propagules for joint propagation of symbionts. These different dispersal strategies ostensibly shape the population genetic structure of lichen symbioses, but the relative contributions of vertical (joint) and horizontal (independent) symbiont transmission have long eluded lichen evolutionary biologists. In this issue of Molecular Ecology, Dal Grande et al. (2012) close in on this question with the lung lichen, Lobaria pulmonaria, a flagship species in the conservation of old growth forests. By capitalizing on available microsatellite markers for both fungal and algal symbionts, they show that while vertical transmission is the predominant mode of reproduction, horizontal transmission is demonstrable and actively shapes population genetic structure. The resulting mixed propagation system is a highly successful balance of safe recruitment of symbiotic clones and endless possibilities for fungal recombination and symbiont shuffling.

  10. Horizontal Transmission of Cytosolic Sup35 Prions by Extracellular Vesicles

    Directory of Open Access Journals (Sweden)

    Shu Liu

    2016-07-01

    Full Text Available Prions are infectious protein particles that replicate by templating their aggregated state onto soluble protein of the same type. Originally identified as the causative agent of transmissible spongiform encephalopathies, prions in yeast (Saccharomyces cerevisiae are epigenetic elements of inheritance that induce phenotypic changes of their host cells. The prototype yeast prion is the translation termination factor Sup35. Prions composed of Sup35 or its modular prion domain NM are heritable and are transmitted vertically to progeny or horizontally during mating. Interestingly, in mammalian cells, protein aggregates derived from yeast Sup35 NM behave as true infectious entities that employ dissemination strategies similar to those of mammalian prions. While transmission is most efficient when cells are in direct contact, we demonstrate here that cytosolic Sup35 NM prions are also released into the extracellular space in association with nanometer-sized membrane vesicles. Importantly, extracellular vesicles are biologically active and are taken up by recipient cells, where they induce self-sustained Sup35 NM protein aggregation. Thus, in mammalian cells, extracellular vesicles can serve as dissemination vehicles for protein-based epigenetic information transfer.

  11. Reductive genome evolution, host-symbiont co-speciation and uterine transmission of endosymbiotic bacteria in bat flies.

    Science.gov (United States)

    Hosokawa, Takahiro; Nikoh, Naruo; Koga, Ryuichi; Satô, Masahiko; Tanahashi, Masahiko; Meng, Xian-Ying; Fukatsu, Takema

    2012-03-01

    Bat flies of the family Nycteribiidae are known for their extreme morphological and physiological traits specialized for ectoparasitic blood-feeding lifestyle on bats, including lack of wings, reduced head and eyes, adenotrophic viviparity with a highly developed uterus and milk glands, as well as association with endosymbiotic bacteria. We investigated Japanese nycteribiid bat flies representing 4 genera, 8 species and 27 populations for their bacterial endosymbionts. From all the nycteribiid species examined, a distinct clade of gammaproteobacteria was consistently detected, which was allied to endosymbionts of other insects such as Riesia spp. of primate lice and Arsenophonus spp. of diverse insects. In adult insects, the endosymbiont was localized in specific bacteriocytes in the abdomen, suggesting an intimate host-symbiont association. In adult females, the endosymbiont was also found in the cavity of milk gland tubules, which suggests uterine vertical transmission of the endosymbiont to larvae through milk gland secretion. In adult females of Penicillidia jenynsii, we discovered a previously unknown type of symbiotic organ in the Nycteribiidae: a pair of large bacteriomes located inside the swellings on the fifth abdominal ventral plate. The endosymbiont genes consistently exhibited adenine/thymine biased nucleotide compositions and accelerated rates of molecular evolution. The endosymbiont genome was estimated to be highly reduced, ~0.76 Mb in size. The endosymbiont phylogeny perfectly mirrored the host insect phylogeny, indicating strict vertical transmission and host-symbiont co-speciation in the evolutionary course of the Nycteribiidae. The designation 'Candidatus Aschnera chinzeii' is proposed for the endosymbiont clade.

  12. Can maternally inherited endosymbionts adapt to a novel host? Direct costs of Spiroplasma infection, but not vertical transmission efficiency, evolve rapidly after horizontal transfer into D. melanogaster.

    Science.gov (United States)

    Nakayama, S; Parratt, S R; Hutchence, K J; Lewis, Z; Price, T A R; Hurst, G D D

    2015-06-01

    Maternally inherited symbionts are common in arthropods and many have important roles in host adaptation. The observation that specific symbiont lineages infect distantly related host species implies new interactions are commonly established by lateral transfer events. However, studies have shown that symbionts often perform poorly in novel hosts. We hypothesized selection on the symbiont may be sufficiently rapid that poor performance in a novel host environment is rapidly ameliorated, permitting symbiont maintenance. Here, we test this prediction for a Spiroplasma strain transinfected into the novel host Drosophila melanogaster. In the generations immediately following transinfection, the symbiont had low transmission efficiency to offspring and imposed severe fitness costs on its host. We observed that effects on host fitness evolved rapidly, being undetectable after 17 generations in the novel host, whereas vertical transmission efficiency was poorly responsive over this period. Our results suggest that long-term symbiosis may more readily be established in cases where symbionts perform poorly in just one aspect of symbiosis.

  13. Interaction between workers during a short time window is required for bacterial symbiont transmission in Acromyrmex leaf-cutting ants.

    Science.gov (United States)

    Marsh, Sarah E; Poulsen, Michael; Pinto-Tomás, Adrián; Currie, Cameron R

    2014-01-01

    Stable associations between partners over time are critical for the evolution of mutualism. Hosts employ a variety of mechanisms to maintain specificity with bacterial associates. Acromyrmex leaf-cutting ants farm a fungal cultivar as their primary nutrient source. These ants also carry a Pseudonocardia Actinobacteria exosymbiont on their bodies that produces antifungal compounds that help inhibit specialized parasites of the ants' fungal garden. Major workers emerge from their pupal cases (eclose) symbiont-free, but exhibit visible Actinobacterial coverage within 14 days post-eclosion. Using subcolony experiments, we investigate exosymbiont transmission within Acromyrmex colonies. We found successful transmission to newly eclosed major workers fostered by major workers with visible Actinobacteria in all cases (100% acquiring, n = 19). In contrast, newly eclosed major workers reared without exosymbiont-carrying major workers did not acquire visible Actinobacteria (0% acquiring, n = 73). We further show that the majority of ants exposed to major workers with exosymbionts within 2 hours of eclosion acquired bacteria (60.7% acquiring, n = 28), while normal acquisition did not occur when exposure occurred later than 2 hours post-eclosion (0% acquiring, n = 18). Our findings show that transmission of exosymbionts to newly eclosed major workers occurs through interactions with exosymbiont-covered workers within a narrow time window after eclosion. This mode of transmission likely helps ensure the defensive function within colonies, as well as specificity and partner fidelity in the ant-bacterium association.

  14. Evidence for Vertical Transmission of Bacterial Symbionts from Adult to Embryo in the Caribbean Sponge Svenzea zeai

    KAUST Repository

    Lee, O. O.

    2009-07-31

    The Caribbean reef sponge Svenzea zeai was previously found to contain substantial quantities of unicellular photosynthetic and autotrophic microbes in its tissues, but the identities of these symbionts and their method of transfer from adult to progeny are largely unknown. In this study, both a 16S rRNA gene-based fingerprinting technique (denaturing gradient gel electrophoresis [DGGE]) and clone library analysis were applied to compare the bacterial communities associated with adults and embryos of S. zeai to test the hypothesis of vertical transfer across generations. In addition, the same techniques were applied to the bacterial community from the seawater adjacent to adult sponges to test the hypothesis that water column bacteria could be transferred horizontally as sponge symbionts. Results of both DGGE and clone library analysis support the vertical transfer hypothesis in that the bacterial communities associated with sponge adults and embryos were highly similar to each other but completely different from those in the surrounding seawater. Sequencing of prominent DGGE bands and of clones from the libraries revealed that the bacterial communities associated with the sponge, whether adult or embryo, consisted of a large proportion of bacteria in the phyla Chloroflexi and Acidobacteria, while most of the sequences recovered from the community in the adjacent water column belonged to the class Alphaproteobacteria. Altogether, 21 monophyletic sequence clusters, comprising sequences from both sponge adults and embryos but not from the seawater, were identified. More than half of the sponge-derived sequences fell into these clusters. Comparison of sequences recovered in this study with those deposited in GenBank revealed that more than 75% of S. zeai-derived sequences were closely related to sequences derived from other sponge species, but none of the sequences recovered from the seawater column overlapped with those from adults or embryos of S. zeai. In

  15. Horizontal and vertical transmission of wild-type and recombinant Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus

    NARCIS (Netherlands)

    Zhou, M.; Sun, X.; Sun, X.C.; Vlak, J.M.; Hu, Z.H.; Werf, van der W.

    2005-01-01

    Transmission plays a central role in the ecology of baculoviruses and the population dynamics of their hosts. Here, we report on the horizontal and vertical transmission dynamics of wild-type Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV-WT) and a genetically modified variant

  16. The effect of a live vaccine on the horizontal transmission of Mycoplasma gallisepticum

    NARCIS (Netherlands)

    Feberwee, A.; Landman, W.J.M.; Banniseht-Wysmuller, von T.E.; Klinkenberg, D.; Vernooij, J.C.M.; Gielkens, A.L.J.; Stegeman, J.A.

    2006-01-01

    The effect of a live Mycoplasma gallisepticum vaccine on the horizontal transmission of this Mycoplasma species was quantified in an experimental animal transmission model in specific pathogen free White Layers. Two identical trials were performed, each consisting of two experimental groups and one

  17. Horizontal and vertical transmission of wild-type and recombinant Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus

    NARCIS (Netherlands)

    Zhou, M.; Sun, X.; Sun, X.C.; Vlak, J.M.; Hu, Z.H.; Werf, van der W.

    2005-01-01

    Transmission plays a central role in the ecology of baculoviruses and the population dynamics of their hosts. Here, we report on the horizontal and vertical transmission dynamics of wild-type Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV-WT) and a genetically modified variant

  18. Symbiont acquisition strategy drives host-symbiont associations in the southern Great Barrier Reef

    Science.gov (United States)

    Stat, M.; Loh, W. K. W.; Hoegh-Guldberg, O.; Carter, D. A.

    2008-12-01

    Coral larvae acquire populations of the symbiotic dinoflagellate Symbiodinium from the external environment (horizontal acquisition) or inherit their symbionts from the parent colony (maternal or vertical acquisition). The effect of the symbiont acquisition strategy on Symbiodinium-host associations has not been fully resolved. Previous studies have provided mixed results, probably due to factors such as low sample replication of Symbiodinium from a single coral host, biogeographic differences in Symbiodinium diversity, and the presence of some apparently host-specific symbiont lineages in coral with either symbiont acquisition strategies. This study set out to assess the effect of the symbiont acquisition strategy by sampling Symbiodinium from 10 coral species (five with a horizontal and five with a vertical symbiont acquisition strategy) across two adjacent reefs in the southern Great Barrier Reef. Symbiodinium diversity was assessed using single-stranded conformational polymorphism of partial nuclear large subunit rDNA and denaturing gradient gel electrophoresis of the internal transcribed spacer 2 region. The Symbiodinium population in hosts with a vertical symbiont acquisition strategy partitioned according to coral species, while hosts with a horizontal symbiont acquisition strategy shared a common symbiont type across the two reef environments. Comparative analysis of existing data from the southern Great Barrier Reef found that the majority of corals with a vertical symbiont acquisition strategy associated with distinct species- or genus-specific Symbiodinium lineages, but some could also associate with symbiont types that were more commonly found in hosts with a horizontal symbiont acquisition strategy.

  19. Suspected dog bite associated HIV horizontal transmission in Swaziland

    Directory of Open Access Journals (Sweden)

    Ganizani Mlawanda

    2013-01-01

    Full Text Available Background: Dog bites may lead to transmission of bacteria and viruses over and above tetanus and rabies. Theoretically human immunodeficiency virus (HIV, Hepatitis B and Hepatitis C may be transmitted after dog bites where transfer of blood from one victim to another occur in clinical practice HIV, Hepatitis B and Hepatitis C are not considered when making treatment decisions, nor adequate patient history taken to consider all potential risks after dog bites in succession.Objective: To present case of suspected HIV transmission after dog bites in close succession involving two HIV sero-discordant victims.Management and outcome: HIV rapid test and/or HIV Ribonucleic acid (RNA polymerasechain reaction (PCR results for the victim(s at presentation and a month later.Results: Two night patrol guards presented to casualty after dog bites in close succession by the same dog. They were managed according to the dog bite protocol. Thinking out of the box, the first victim was found to be HIV positive by rapid test whilst the second victim was negative based on both HIV rapid test and HIV RNA PCR. One month after the dogbites, a case of HIV sero-conversion was confirmed in the second victim despite post-exposure prophylaxis (PEP.Discussion: Although an isolated case, shouldn’t clinicians re-think the significance of HIV transmission after animal bites where there is repeated blood exposure in several people insuccession?Conclusion: Clinicians should be aware of the potential of HIV, Hepatitis B and C transmission, when faced with dog bites in succession. 

  20. Lassa serology in natural populations of rodents and horizontal transmission.

    Science.gov (United States)

    Fichet-Calvet, Elisabeth; Becker-Ziaja, Beate; Koivogui, Lamine; Günther, Stephan

    2014-09-01

    Lassa virus causes hemorrhagic fever in West Africa. Previously, we demonstrated by PCR screening that only the multimammate mouse, Mastomys natalensis, hosts Lassa virus in Guinea. In the present study, we used the same specimen collection from 17 villages in Coastal, Upper, and Forest Guinea to investigate the Lassa virus serology in the rodent population. The aim was to determine the dynamics of antibody development in M. natalensis and to detect potential spillover infections in other rodent species. Immunoglobulin G (IgG) antibody screening was performed using the indirect immunofluorescence assay with the Guinean Lassa virus strain Bantou 289 as antigen. The overall seroprevalence was 8% (129/1551) with the following rodents testing positive: 109 M. natalensis, seven Mastomys erythroleucus, four Lemniscomys striatus, four Praomys daltoni, three Mus minutoides, and two Praomys rostratus. Nearly all of them (122/129) originated from Bantou, Tanganya, and Gbetaya, where Lassa virus is highly endemic in M. natalensis. The antibody seroprevalence in M. natalensis from this high-endemic area (27%; 108/396) depended on the village, habitat, host age, and host abundance. A main positive factor was age; the maximum seroprevalence reached 50% in older animals. Our data fit with a model implicating that most M. natalensis rodents become horizontally infected, clear the virus within a period significantly shorter than their life span, and develop antibodies. In addition, the detection of antibodies in other species trapped in the habitats of M. natalensis suggests spillover infections.

  1. Wolbachia screening in spiders and assessment of horizontal transmission between predator and prey.

    Science.gov (United States)

    Yun, Y; Peng, Y; Liu, F X; Lei, C

    2011-01-01

    Recent studies have revealed that the prevalence of Wolbachia in arthropods is attributable not only to its vertical transmission, but also to its horizontal transfer. In order to assess the horizontal transmission of Wolbachia between predator and prey, arthropods belonging to 11 spider families and six insect families were collected in the same field of rice. The distribution of Wolbachia in these arthropods was detected by diagnostic PCR amplification of the wsp (Wolbachia outer surface protein gene) and 16S rDNA genes. Nurscia albofasciata Strand (Araneae: Titanoecidae), Propylea japonica Thunberg (Coleoptera: Coccinellidae), Paederus fuscipes Curtis (Coleoptera: Staphylinidae), and Nilaparvata lugens Stal (Homoptera: Delphacidae) were infected with Wolbachia. This is the first report of infection of N. albofasciata and P. fuscipes by Wolbachia. No direct evidence indicated the existence of horizontal transmission of Wolbachia between predator and prey.

  2. Synaptic transmission from horizontal cells to cones is impaired by loss of connexin hemichannels.

    Directory of Open Access Journals (Sweden)

    Lauw J Klaassen

    2011-07-01

    step in resolving a long-standing debate about the unusual form of (ephaptic synaptic transmission between horizontal cells and cones in the vertebrate retina.

  3. The intracellular bacterium Wolbachia uses parasitoid wasps as phoretic vectors for efficient horizontal transmission.

    Directory of Open Access Journals (Sweden)

    Muhammad Z Ahmed

    2015-02-01

    Full Text Available Facultative bacterial endosymbionts are associated with many arthropods and are primarily transmitted vertically from mother to offspring. However, phylogenetic affiliations suggest that horizontal transmission must also occur. Such horizontal transfer can have important biological and agricultural consequences when endosymbionts increase host fitness. So far horizontal transmission is considered rare and has been difficult to document. Here, we use fluorescence in situ hybridization (FISH and multi locus sequence typing (MLST to reveal a potentially common pathway of horizontal transmission of endosymbionts via parasitoids of insects. We illustrate that the mouthparts and ovipositors of an aphelinid parasitoid become contaminated with Wolbachia when this wasp feeds on or probes Wolbachia-infected Bemisia tabaci AsiaII7, and non-lethal probing of uninfected B. tabaci AsiaII7 nymphs by parasitoids carrying Wolbachia resulted in newly and stably infected B. tabaci matrilines. After they were exposed to infected whitefly, the parasitoids were able to transmit Wolbachia efficiently for the following 48 h. Whitefly infected with Wolbachia by parasitoids had increased survival and reduced development times. Overall, our study provides evidence for the horizontal transmission of Wolbachia between insect hosts by parasitic wasps, and the enhanced survival and reproductive abilities of insect hosts may adversely affect biological control programs.

  4. Evidence for a Symbiosis Island Involved in Horizontal Acquisition of Pederin Biosynthetic Capabilities by the Bacterial Symbiont of Paederus fuscipes Beetles

    OpenAIRE

    Piel, Jörn; Höfer, Ivonne; Hui, Dequan

    2004-01-01

    Pederin belongs to a group of antitumor compounds found in terrestrial beetles and marine sponges. It is used by apparently all members of the rove beetle genera Paederus and Paederidus as a chemical defense against predators. However, a recent analysis of the putative pederin biosynthesis (ped) gene cluster strongly suggests that pederin is produced by bacterial symbionts. We have sequenced an extended region of the symbiont genome to gain further insight into the biology of this as-yet-uncu...

  5. Similar sponge-associated bacteria can be acquired via both vertical and horizontal transmission.

    Science.gov (United States)

    Sipkema, Detmer; de Caralt, Sònia; Morillo, Jose A; Al-Soud, Waleed Abu; Sørensen, Søren J; Smidt, Hauke; Uriz, María J

    2015-10-01

    Marine sponges host diverse communities of microorganisms that are often vertically transmitted from mother to oocyte or embryo. Horizontal transmission has often been proposed to co-occur in marine sponges, but the mechanism is poorly understood. To assess the impact of the mode of transmission on the microbial assemblages of sponges, we analysed the microbiota in sympatric sponges that have previously been reported to acquire bacteria via either vertical (Corticium candelabrum and Crambe crambe) or horizontal transmission (Petrosia ficiformis). The comparative study was performed by polymerase chain reaction-denaturing gradient gel electrophoresis and pyrosequencing of barcoded PCR-amplified 16S rRNA gene fragments. We found that P. ficiformis and C. candelabrum each harbour their own species-specific bacteria, but they are similar to other high-microbial-abundance sponges, while the low-microbial-abundance sponge C. crambe hosts microbiota of a very different phylogenetic signature. In addition, nearly 50% of the reads obtained from P. ficiformis were most closely related to bacteria that were previously reported to be vertically transmitted in other sponges and comprised vertical-horizontal transmission phylogenetic clusters (VHT clusters). Therefore, our results provide evidence for the hypothesis that similar sponge-associated bacteria can be acquired via both vertical and horizontal transmission.

  6. Similar sponge-associated bacteria can be acquired via both vertical and horizontal transmission

    DEFF Research Database (Denmark)

    Sipkema, Detmer; de Caralt, Sònia; Morillo, Jose A

    2015-01-01

    Marine sponges host diverse communities of microorganisms that are often vertically transmitted from mother to oocyte or embryo. Horizontal transmission has often been proposed to co-occur in marine sponges, but the mechanism is poorly understood. To assess the impact of the mode of transmission...... on the microbial assemblages of sponges, we analysed the microbiota in sympatric sponges that have previously been reported to acquire bacteria via either vertical (Corticium candelabrum and Crambe crambe) or horizontal transmission (Petrosia ficiformis). The comparative study was performed by PCR......-DGGE and pyrosequencing of barcoded PCR-amplified 16S rRNA gene fragments. We found that P. ficiformis and C. candelabrum each harbor their own species-specific bacteria, but they are similar to other high-microbial-abundance sponges, while the low-microbial-abundance sponge C. crambe hosts microbiota of a very different...

  7. Horizontal and vertical transmission of wild-type and recombinant Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus.

    Science.gov (United States)

    Zhou, Mingzhe; Sun, Xiulian; Sun, Xincheng; Vlak, Just M; Hu, Zhihong; van der Werf, Wopke

    2005-06-01

    Transmission plays a central role in the ecology of baculoviruses and the population dynamics of their hosts. Here, we report on the horizontal and vertical transmission dynamics of wild-type Helicoverpa armigera single-nucleocapsid nucleopolyhedrovirus (HaSNPV-WT) and a genetically modified variant (HaSNPV-AaIT) with enhanced speed of action through the expression of an insect-selective scorpion toxin (AaIT). In caged field plots, horizontal transmission of both HaSNPV variants was greatest when inoculated 3rd instar larvae were used as infectors, transmission was intermediate with 2nd instar infectors and lowest with 1st instar infectors. Transmission was greater at a higher density of infectors (1 per plant) than at a lower density (1 per 4 plants); however, the transmission coefficient (number of new infections per initial infector) was lower at the higher density of infectors than at the lower density. HaSNPV-AaIT exhibited a significantly lower rate of transmission than HaSNPV-WT in the field cages. This was also the case in open field experiments. In the laboratory, the vertical transmission of HaSNPV-AaIT from infected females to offspring of 16.7+/-2.1% was significantly lower than that of HaSNPV-WT (30.9+/-2.9%). Likewise, in the field, vertical transmission of HaSNPV-AaIT (8.4+/-1.1%) was significantly lower than that of HaSNPV-WT (12.6+/-2.0%). The results indicate that the recombinant virus will be transmitted at lower rates in H. armigera populations than the wild-type virus. This may potentially affect negatively its long-term efficacy as compared to wild-type virus, but contributing positively to its biosafety.

  8. The bivalve Thyasira cf. gouldi hosts chemoautotrophic symbiont populations with strain level diversity

    Directory of Open Access Journals (Sweden)

    Bonita McCuaig

    2017-07-01

    Full Text Available Invertebrates from various marine habitats form nutritional symbioses with chemosynthetic bacteria. In chemosynthetic symbioses, both the mode of symbiont transmission and the site of bacterial housing can affect the composition of the symbiont population. Vertically transmitted symbionts, as well as those hosted intracellularly, are more likely to form clonal populations within their host. Conversely, symbiont populations that are environmentally acquired and extracellular may be more likely to be heterogeneous/mixed within host individuals, as observed in some mytilid bivalves. The symbionts of thyasirid bivalves are also extracellular, but limited 16S rRNA sequencing data suggest that thyasirid individuals contain uniform symbiont populations. In a recent study, Thyasira cf. gouldi individuals from Bonne Bay, Newfoundland, Canada were found to host one of three 16S rRNA phylotypes of sulfur-oxidizing gammaproteobacteria, suggesting environmental acquisition of symbionts and some degree of site-specificity. Here, we use Sanger sequencing of both 16S RNA and the more variable ribulose-1,5-bisphosphate carboxylase (RuBisCO PCR products to further examine Thyasira cf. gouldi symbiont diversity at the scale of host individuals, as well as to elucidate any temporal or spatial patterns in symbiont diversity within Bonne Bay, and relationships with host OTU or size. We obtained symbiont 16S rRNA and RuBisCO Form II sequences from 54 and 50 host individuals, respectively, during nine sampling trips to three locations over four years. Analyses uncovered the same three closely related 16S rRNA phylotypes obtained previously, as well as three divergent RuBisCO phylotypes; these were found in various pair combinations within host individuals, suggesting incidents of horizontal gene transfer during symbiont evolution. While we found no temporal patterns in phylotype distribution or relationships with host OTU or size, some spatial effects were noted, with

  9. Horizontal transmission of Salmonella Enteritidis in experimentally infected laying hens housed in conventional or enriched cages.

    Science.gov (United States)

    Gast, Richard K; Guraya, Rupa; Jones, Deana R; Anderson, Kenneth E

    2014-12-01

    The majority of human illnesses caused by Salmonella Enteritidis are attributed to contaminated eggs, and the prevalence of this pathogen in commercial laying flocks has been identified as a leading epidemiologic risk factor. Flock housing and management systems can affect opportunities for the introduction, transmission, and persistence of foodborne pathogens in poultry. The animal welfare implications of different types of housing for laying hens have been widely discussed in recent years, but the food safety consequences of these production systems remain incompletely understood. The present study assessed the effects of 2 different housing systems (conventional cages and colony cages enriched with perching and nesting areas) on the horizontal transmission of experimentally introduced Salmonella Enteritidis infection within groups of laying hens. In each of 2 trials, 136 hens were distributed among cages of both housing systems and approximately one-third of the hens in each cage were orally inoculated with doses of 10(8) cfu of Salmonella Enteritidis (phage type 13a in one trial and phage type 4 in the other). At regular intervals through 23 d postinoculation, cloacal swabs were collected from all hens (inoculated and uninoculated) and cultured for Salmonella Enteritidis. Horizontal contact transmission of infection was observed for both Salmonella Enteritidis strains, reaching peak prevalence values of 27.1% of uninoculated hens in conventional cages and 22.7% in enriched cages. However, no significant differences (P > 0.05) in the overall frequencies of horizontal Salmonella Enteritidis transmission were evident between the 2 types of housing. These results suggest that opportunities for Salmonella Enteritidis infection to spread horizontally throughout laying flocks may be similar in conventional and enriched cage-based production systems.

  10. The behaviour of the power transmission tower subjected to horizontal support’s movements

    OpenAIRE

    Shu, Q.; Yuan, G.; Z. Huang; Ye, S.

    2016-01-01

    In this paper, two half-scaled test tower models for a typical 110 kV single-circuit power transmission tower were designed and fabricated. The scaled test tower models were tested under the horizontal support’s stretching (tensile) and compressive movements with the normal working loading conditions. The deformations of the tested tower models and stresses within the different bracing members were fully measured. A large amount of comprehensive test data was generated. Also a finite element ...

  11. Horizontal

    Institute of Scientific and Technical Information of China (English)

    ZHONG; Chunping

    2005-01-01

    [1]Wu, H., Bochner technique in differential geometry, Advance in Math. (in Chinese), 1981, 10(1): 57-76.[2]Morrow, J., Kodaira, K., Complex Manifolds, New York: Holt, Rinehart & Winston, 1971.[3]Abate, M., Aikou, T., Patrizio, G., Preface for Complex Finsler Geometry, Cont. Math., Vol. 196, Providence,RI: Amer. Math. Soc., 1996, 97-100.[4]Abate, M., Patrizio, G., Finsler Metrics-A global approach with applications to geometric function theory,Lecture Notes in Mathematics, Vol. 1591, Bedin: Springer-Verlag, 1994.[5]Antonelli, P. L., Lackey, B.(eds.), The Theory of Finslerian Laplacians and Applications, MAIA 459, Dordrecht:Kluwer Academic Publishers, 1998.[6]Bao, D., Lackey, B., A Hodge decomposition theorem for Finsler spaces, C. R. Acad. Sci. Paris, t. 323, Serie 1,1996, 51-56.[7]Munteanu, O., Weitzenbock formulas for horizontal and vertical Laplacians, Houston Journal of Mathematics,2003, 29(4): 889-900.[8]Faran, J. J., The equivalence problem for complex Finsler Hamiltonians, Cont. Math.,Vol. 196, Providence, RI:Amer. Math. Soc., 1996, 133-144.[9]Kobayashi, S., Complex Finsler vector bundles, Cont. Math., Vol. 196, Providence, RI: Amer. Math. Soc.,1996,145-153.[10]Aikou, T., On complex Finsler manifolds, Rep. Fac. Sci. Kagoshima Univ. (Math. Phys. & Chem.), 1991, 24:9-25.

  12. Horizontal transmission of hepatitis B virus in children with chronic hepatitis B

    Institute of Scientific and Technical Information of China (English)

    Tumay Doganci; Gulnar Uysal; Tayfun Kir; Arzu Bakirtas; Necdet Kuyucu; Levent Doganci

    2005-01-01

    AIM: To determine the possible routes of intrafamilial transmission pattern in pediatric cases of chronic hepatitis B virus (HBV) infection.METHODS: In this descriptive retrospective study, 302 children with chronic HBV infection from 251 families and their parents attending the Social Security Children's Hospital and Doctor Sami Ulus Children's Hopsital in Ankara between December 1998 and May 2000, were enrolled in. Screenings and diagnosis of chronic HBV infections were established according to the Consensus 2000.RESULTS: In the studied 302 children with chronic HBV infection, mothers of 38% and fathers of 23% were HBsAg positive. The HBsAg positivity in at least two siblings of the same family was 61% when both parents were HBsAg positive.CONCLUSION: It is well known that horizontal transmission is quite common in countries where Hepatitis B Virus is moderately endemic. To our best knowledge, this is the largest series observed regarding the horizontal transmission in pediatric chronic HBV infection in Turkey. It is necessary to expand the preventive programs to target not only the newborn period but also all stages of childhood.

  13. Bacterial symbionts in insects or the story of communities affecting communities.

    Science.gov (United States)

    Ferrari, Julia; Vavre, Fabrice

    2011-05-12

    Bacterial symbionts are widespread in insects and other animals. Most of them are predominantly vertically transmitted, along with their hosts' genes, and thus extend the heritable genetic variation present in one species. These passengers have a variety of repercussions on the host's phenotypes: besides the cost imposed on the host for maintaining the symbiont population, they can provide fitness advantages to the host or manipulate the host's reproduction. We argue that insect symbioses are ideal model systems for community genetics. First, bacterial symbionts directly or indirectly affect the interactions with other species within a community. Examples include their involvement in modifying the use of host plants by phytophagous insects, in providing resistance to natural enemies, but also in reducing the global genetic diversity or gene flow between populations within some species. Second, one emerging picture in insect symbioses is that many species are simultaneously infected with more than one symbiont, which permits studying the factors that shape bacterial communities; for example, horizontal transmission, interactions between host genotype, symbiont genotype and the environment and interactions among symbionts. One conclusion is that insects' symbiotic complements are dynamic communities that affect and are affected by the communities in which they are embedded.

  14. Horizontal transmission of novel H1N1/09 influenza virus in a newborn:Myth or fact?

    Institute of Scientific and Technical Information of China (English)

    Uttam Kumar Sarkar; Utpala Mitra; Mamta Chawla Sarkar; Shanta Dutta; Himanish Roy; Mrinal Kanti Chatterjee; Phalguni Dutta

    2012-01-01

    Horizontal transmission of H1N1/09 virus infection is very common however; transmission through this route has not been reported in newborns. To our knowledge, this is the first case report of newborn who acquired infection of novel H1N1/09 virus horizontally through asymptomatic family members or hospital staff during epidemic period in Kolkata, India. Baby recovered without antiviral therapy but received antibiotic for bacterial co-infection.

  15. Horizontal transmissible protection against myxomatosis and rabbit hemorrhagic disease by using a recombinant myxoma virus.

    Science.gov (United States)

    Bárcena, J; Morales, M; Vázquez, B; Boga, J A; Parra, F; Lucientes, J; Pagès-Manté, A; Sánchez-Vizcaíno, J M; Blasco, R; Torres, J M

    2000-02-01

    We have developed a new strategy for immunization of wild rabbit populations against myxomatosis and rabbit hemorrhagic disease (RHD) that uses recombinant viruses based on a naturally attenuated field strain of myxoma virus (MV). The recombinant viruses expressed the RHDV major capsid protein (VP60) including a linear epitope tag from the transmissible gastroenteritis virus (TGEV) nucleoprotein. Following inoculation, the recombinant viruses induced specific antibody responses against MV, RHDV, and the TGEV tag. Immunization of wild rabbits by the subcutaneous and oral routes conferred protection against virulent RHDV and MV challenges. The recombinant viruses showed a limited horizontal transmission capacity, either by direct contact or in a flea-mediated process, promoting immunization of contact uninoculated animals.

  16. Variation in horizontal and vertical transmission of the endophyte Epichloë elymi infecting the grass Elymus hystrix.

    Science.gov (United States)

    Tintjer, Tammy; Leuchtmann, Adrian; Clay, Keith

    2008-01-01

    Systemic fungal endophytes (Clavicipitaceae) of grasses reproduce sexually when the fungus forms stromata and contagious ascospores, or asexually by vertical transmission of hyphae into seeds and seedlings. Vertical transmission is predicted to favor reduced virulence compared with horizontal transmission in systems with both types of transmission. Here, variation in vertical and horizontal transmission and its potential heritability in a host grass-endophyte interaction, Elymus hystrix infected with Epichloë elymi, were examined in natural populations and two common garden experiments using field-collected host tillers and seed progeny of maternal plants with known infection phenotypes. Transmission mode exhibited year-to-year variation in field and common garden environments. In the common garden there were consistent differences among maternal plant families in stroma production and significant correlations between stroma production in the common garden and in natural populations. Transmission mode differed among maternal families, spanning a continuum from pure vertical transmission to a high proportion of stroma production and horizontal transmission potential. Vertical transmission to seeds occurred at high rates in all maternal families regardless of their stroma production. Observed patterns of variation indicate that endophyte transmission mode and correlated changes in virulence can respond to selection by biotic and abiotic factors.

  17. Symbiont-mediated RNA interference in insects.

    Science.gov (United States)

    Whitten, Miranda M A; Facey, Paul D; Del Sol, Ricardo; Fernández-Martínez, Lorena T; Evans, Meirwyn C; Mitchell, Jacob J; Bodger, Owen G; Dyson, Paul J

    2016-02-24

    RNA interference (RNAi) methods for insects are often limited by problems with double-stranded (ds) RNA delivery, which restricts reverse genetics studies and the development of RNAi-based biocides. We therefore delegated to insect symbiotic bacteria the task of: (i) constitutive dsRNA synthesis and (ii) trauma-free delivery. RNaseIII-deficient, dsRNA-expressing bacterial strains were created from the symbionts of two very diverse pest species: a long-lived blood-sucking bug, Rhodnius prolixus, and a short-lived globally invasive polyphagous agricultural pest, western flower thrips (Frankliniella occidentalis). When ingested, the manipulated bacteria colonized the insects, successfully competed with the wild-type microflora, and sustainably mediated systemic knockdown phenotypes that were horizontally transmissible. This represents a significant advance in the ability to deliver RNAi, potentially to a large range of non-model insects.

  18. Swapping symbionts in spittlebugs: evolutionary replacement of a reduced genome symbiont.

    Science.gov (United States)

    Koga, Ryuichi; Moran, Nancy A

    2014-06-01

    Bacterial symbionts that undergo long-term maternal transmission experience elevated fixation of deleterious mutations, resulting in massive loss of genes and changes in gene sequences that appear to limit efficiency of gene products. Potentially, this dwindling of symbiont functionality impacts hosts that depend on these bacteria for nutrition. One evolutionary escape route is the acquisition of a novel symbiont with a robust genome and metabolic capabilities. Such an acquisition has occurred in an ancestor of Philaenus spumarius, the meadow spittlebug (Insecta: Cercopoidea), which has replaced its ancient association with the tiny genome symbiont Zinderia insecticola (Betaproteobacteria) with an association with a symbiont related to Sodalis glossinidius (Gammaproteobacteria). Spittlebugs feed exclusively on xylem sap, a diet that is low both in essential amino acids and in sugar or other substrates for energy production. The new symbiont genome has undergone proliferation of mobile elements resulting in many gene inactivations; nonetheless, it has selectively maintained genes replacing functions of its predecessor for amino-acid biosynthesis. Whereas ancient symbiont partners typically retain perfectly complementary sets of amino-acid biosynthetic pathways, the novel symbiont introduces some redundancy as it retains some pathways also present in the partner symbionts (Sulcia muelleri). Strikingly, the newly acquired Sodalis-like symbiont retains genes underlying efficient routes of energy production, including a complete TCA cycle, potentially relaxing the severe energy limitations of the xylem-feeding hosts. Although evolutionary replacements of ancient symbionts are infrequent, they potentially enable evolutionary and ecological novelty by conferring novel metabolic capabilities to host lineages.

  19. Underwater spark discharge with long transmission line for cleaning horizontal wells

    Science.gov (United States)

    Lee, Kern; Chung, Kyoung-Jae; Hwang, Y. S.; Kim, C. Y.

    2017-06-01

    A transmission line is discussed for application in an underwater spark-discharge technique in the cleaning of a horizontal well by incorporating a power-transmission model into the simulation. The pulsed-spark-discharge technique has been proposed for clogged-well rehabilitation, because it removes incrustations that are attached to well screens by using strong pressure waves that are generated by the rapid expansion of a spark channel. To apply the pulsed-spark-discharge technique to the cleaning of horizontal wells, the coaxial cable between the pulsed power supply and the spark gap as a load needs to be extended to a few hundred meters. Prior to field application, pulsed-spark-discharge experiments were conducted and the role of the transmission line was examined using an improved simulation model. In the model, a non-linear interaction of the spark channel and the capacitor bank is described by the pulse-forming action of the coaxial cable. Based on the accurate physical properties of the water plasma, such as the equation of state and electrical conductivity within the region of interest, the amount of energy contributed to the development of a shock wave was evaluated. The simulation shows that if the initial conditions of the spark channel are the same, no further reduction in strength of the pressure wave occurs, even if the cable length is increased above 50 m. Hence, the degraded peak pressure that was observed in the experiments using the longer cable is attributed to a change in the initial condition of the spark channel. The parametric study suggests that the low initial charging voltage, the high ambient water pressure, and the long cable length yield the low initial spark-channel density, which results in a reduced peak pressure. The simulation of line charging is presented to discuss the principle of disturbing the pre-breakdown process by an extended cable.

  20. Swapping symbionts in spittlebugs: evolutionary replacement of a reduced genome symbiont

    OpenAIRE

    Koga, Ryuichi; Moran, Nancy A.

    2014-01-01

    Bacterial symbionts that undergo long-term maternal transmission experience elevated fixation of deleterious mutations, resulting in massive loss of genes and changes in gene sequences that appear to limit efficiency of gene products. Potentially, this dwindling of symbiont functionality impacts hosts that depend on these bacteria for nutrition. One evolutionary escape route is the acquisition of a novel symbiont with a robust genome and metabolic capabilities. Such an acquisition has occurre...

  1. Horizontal Transmission of Beauveria bassiana (Hypocreales: Cordycipitaceae) and Metarhizium anisopliae (Hypocreales: Clavicipitaceae) in Musca domestica (Diptera: Muscidae).

    Science.gov (United States)

    Cárcamo, M C; Felchicher, F; Duarte, J P; Bernardi, E; Ribeiro, P B

    2015-08-01

    Beauveria bassiana Vuillemin and Metarhizium anisopliae (Metschnikoff) Sorokin are fungi with potential for controlling Musca domestica L. However, the impact on this dipteral may vary depending on the fungal isolates and the methodology used. This study evaluated the pathogenicity of direct application and horizontal transmission of B. bassiana (CG240) and M. anisopliae (CG34) on adult M. domestica individuals. The impact of B. bassiana and M. anisopliae on M. domestica was evaluated at the concentrations 2 × 10(4), 2 × 10(5), 2 × 10(6), and 2 × 10(7) conidia/ml. Horizontal transmission was also estimated between sexes at different infection periods of the vector insect. The mortality of adult M. domestica individuals directly infected with B. bassiana was above 90%, and the mortality of those infected with M. anisopliae ranged from 25.50 to 97.78%. Horizontal transmission of B. bassiana caused the death of 100% of individuals, in turn, that of M. anisopliae killed 55% of male and 100% of female individuals. Horizontal transmission of fungi was negatively influenced by time. This study shows the potential of these fungi for controlling M. domestica, both with the direct implementation strategy and horizontal transmission. However, field studies are needed to evaluate the capacity to decrease the M. domestica population using these alternatives.

  2. Horizontal Price Transmission in Agricultural Markets: Fundamental Concepts and Open Empirical Issues

    Directory of Open Access Journals (Sweden)

    Giulia Listorti

    2012-05-01

    Full Text Available Following the dramatic changes experienced by the prices of agricultural commodities in 2007-2008, the analysis of horizontal price transmission mechanisms in agricultural markets has attracted renewed interest. In particular, this has led to the emergence of new challenges for the empirical analysis. How to model the increasing volatility and non linear behaviour of prices, to assess the impact of the policy responses to market turbulence, and how to account for the increasing interconnections between agricultural and non-agricultural commodity markets are amongst the most investigated issues. Building on a common analytical framework, this paper discusses and reviews the most recent methodological developments and empirical contributions in the field.

  3. Doubling transmission capacity in optical wireless system by antenna horizontal- and vertical-polarization multiplexing.

    Science.gov (United States)

    Li, Xinying; Yu, Jianjun; Zhang, Junwen; Dong, Ze; Chi, Nan

    2013-06-15

    We experimentally demonstrate 2×56 Gb/s two-channel polarization-division-multiplexing quadrature-phase-shift-keying signal delivery over 80 km single-mode fiber-28 and 2 m Q-band (33-50 GHz) wireless link, adopting antenna horizontal- (H-) and vertical-polarization (V-polarization) multiplexing. At the wireless receiver, classic constant-modulus-algorithm equalization based on digital signal processing can realize polarization demultiplexing and remove the crosstalk at the same antenna polarization. By adopting antenna polarization multiplexing, the signal baud rate and performance requirements for optical and wireless devices can be reduced but at the cost of double antennas and devices, while wireless transmission capacity can also be increased but at the cost of stricter requirements for V-polarization. The isolation is only about 19 dB when V-polarization deviation approaches 10°, which will affect high-speed (>50 Gb/s) wireless delivery.

  4. Phylogenetic Analysis Supports Horizontal Transmission as a Driving Force of the Spread of Avian Bornaviruses.

    Science.gov (United States)

    Rubbenstroth, Dennis; Schmidt, Volker; Rinder, Monika; Legler, Marko; Twietmeyer, Sönke; Schwemmer, Phillip; Corman, Victor M

    2016-01-01

    Avian bornaviruses are a genetically diverse group of viruses initially discovered in 2008. They are known to infect several avian orders. Bornaviruses of parrots and related species (Psittaciformes) are causative agents of proventricular dilatation disease, a chronic and often fatal neurologic disease widely distributed in captive psittacine populations. Although knowledge has considerably increased in the past years, many aspects of the biology of avian bornaviruses are still undiscovered. In particular, the precise way of transmission remains unknown. In order to collect further information on the epidemiology of bornavirus infections in birds we collected samples from captive and free-ranging aquatic birds (n = 738) and Passeriformes (n = 145) in Germany and tested them for the presence of bornaviruses by PCR assays covering a broad range of known bornaviruses. We detected aquatic bird bornavirus 1 (ABBV-1) in three out of 73 sampled free-ranging mute swans (Cygnus olor) and one out of 282 free-ranging Eurasian oystercatchers (Haematopus ostralegus). Canary bornavirus 1 (CnBV-1), CnBV-2 and CnBV-3 were detected in four, six and one out of 48 captive common canaries (Serinus canaria forma domestica), respectively. In addition, samples originating from 49 bornavirus-positive captive Psittaciformes were used for determination of parrot bornavirus 2 (PaBV-2) and PaBV-4 sequences. Bornavirus sequences compiled during this study were used for phylogenetic analysis together with all related sequences available in GenBank. Within ABBV-1, PaBV-2 and PaBV-4, identical or genetically closely related bornavirus sequences were found in parallel in various different avian species, suggesting that inter-species transmission is frequent relative to the overall transmission of these viruses. Our results argue for an important role of horizontal transmission, but do not exclude the additional possibility of vertical transmission. Furthermore we defined clearly separated sequence

  5. Phylogenetic Analysis Supports Horizontal Transmission as a Driving Force of the Spread of Avian Bornaviruses

    Science.gov (United States)

    Rubbenstroth, Dennis; Schmidt, Volker; Rinder, Monika; Legler, Marko; Twietmeyer, Sönke; Schwemmer, Phillip; Corman, Victor M.

    2016-01-01

    Background Avian bornaviruses are a genetically diverse group of viruses initially discovered in 2008. They are known to infect several avian orders. Bornaviruses of parrots and related species (Psittaciformes) are causative agents of proventricular dilatation disease, a chronic and often fatal neurologic disease widely distributed in captive psittacine populations. Although knowledge has considerably increased in the past years, many aspects of the biology of avian bornaviruses are still undiscovered. In particular, the precise way of transmission remains unknown. Aims and Methods In order to collect further information on the epidemiology of bornavirus infections in birds we collected samples from captive and free-ranging aquatic birds (n = 738) and Passeriformes (n = 145) in Germany and tested them for the presence of bornaviruses by PCR assays covering a broad range of known bornaviruses. We detected aquatic bird bornavirus 1 (ABBV-1) in three out of 73 sampled free-ranging mute swans (Cygnus olor) and one out of 282 free-ranging Eurasian oystercatchers (Haematopus ostralegus). Canary bornavirus 1 (CnBV-1), CnBV-2 and CnBV-3 were detected in four, six and one out of 48 captive common canaries (Serinus canaria forma domestica), respectively. In addition, samples originating from 49 bornavirus-positive captive Psittaciformes were used for determination of parrot bornavirus 2 (PaBV-2) and PaBV-4 sequences. Bornavirus sequences compiled during this study were used for phylogenetic analysis together with all related sequences available in GenBank. Results of the Study Within ABBV-1, PaBV-2 and PaBV-4, identical or genetically closely related bornavirus sequences were found in parallel in various different avian species, suggesting that inter-species transmission is frequent relative to the overall transmission of these viruses. Our results argue for an important role of horizontal transmission, but do not exclude the additional possibility of vertical transmission

  6. Interaction between workers during a short time window is required for bacterial symbiont transmission in Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Marsh, Sarah E.; Thomas-Poulsen, Michael; Pinto-Tomás, Adrián;

    2014-01-01

    Stable associations between partners over time are critical for the evolution of mutualism. Hosts employ a variety of mechanisms to maintain specificity with bacterial associates. Acromyrmex leaf-cutting ants farm a fungal cultivar as their primary nutrient source. These ants also carry a Pseudon......Stable associations between partners over time are critical for the evolution of mutualism. Hosts employ a variety of mechanisms to maintain specificity with bacterial associates. Acromyrmex leaf-cutting ants farm a fungal cultivar as their primary nutrient source. These ants also carry...... occurred later than 2 hours post-eclosion (0% acquiring, n = 18). Our findings show that transmission of exosymbionts to newly eclosed major workers occurs through interactions with exosymbiont-covered workers within a narrow time window after eclosion. This mode of transmission likely helps ensure...

  7. Virus-mediated suppression of host non-self recognition facilitates horizontal transmission of heterologous viruses

    Science.gov (United States)

    Wu, Songsong; Cheng, Jiasen; Fu, Yanping; Chen, Tao; Jiang, Daohong; Ghabrial, Said A.

    2017-01-01

    Non-self recognition is a common phenomenon among organisms; it often leads to innate immunity to prevent the invasion of parasites and maintain the genetic polymorphism of organisms. Fungal vegetative incompatibility is a type of non-self recognition which often induces programmed cell death (PCD) and restricts the spread of molecular parasites. It is not clearly known whether virus infection could attenuate non-self recognition among host individuals to facilitate its spread. Here, we report that a hypovirulence-associated mycoreovirus, named Sclerotinia sclerotiorum mycoreovirus 4 (SsMYRV4), could suppress host non-self recognition and facilitate horizontal transmission of heterologous viruses. We found that cell death in intermingled colony regions between SsMYRV4-infected Sclerotinia sclerotiorum strain and other tested vegetatively incompatible strains was markedly reduced and inhibition barrage lines were not clearly observed. Vegetative incompatibility, which involves Heterotrimeric guanine nucleotide-binding proteins (G proteins) signaling pathway, is controlled by specific loci termed het (heterokaryon incompatibility) loci. Reactive oxygen species (ROS) plays a key role in vegetative incompatibility-mediated PCD. The expression of G protein subunit genes, het genes, and ROS-related genes were significantly down-regulated, and cellular production of ROS was suppressed in the presence of SsMYRV4. Furthermore, SsMYRV4-infected strain could easily accept other viruses through hyphal contact and these viruses could be efficiently transmitted from SsMYRV4-infected strain to other vegetatively incompatible individuals. Thus, we concluded that SsMYRV4 is capable of suppressing host non-self recognition and facilitating heterologous viruses transmission among host individuals. These findings may enhance our understanding of virus ecology, and provide a potential strategy to utilize hypovirulence-associated mycoviruses to control fungal diseases. PMID:28334041

  8. Stroma-bearing endophyte and its potential horizontal transmission ability in Achnatherum sibiricum.

    Science.gov (United States)

    Li, Xia; Zhou, Yong; Zhu, Minjie; Qin, Junhua; Ren, Anzhi; Gao, Yubao

    2015-01-01

    Stromata occasionally are observed in Achnatherum sibiricum distributed in northern China. However, endophyte species that form stromata on that host have not been studied. Here we identified the first Epichloë sp. endophyte in stroma-bearing A. sibiricum. Isolated colonies of this Epichloë sp. were smoother and more compact than previously described for Epichloë gansuensis and also had longer phialides and faster growth in culture. However, phylogenetic relationships based on intron sequences of genes encoding β-tubulin (tubB) and translation elongation factor 1-α (tefA) grouped all isolates from the stromata in a clade with a close relationship to E. gansuensis. We identified the new isolates as E. gansuensis. The analysis of the stromata revealed no perithecium or ascospores during morphological and paraffin section observation. Furthermore, the ability of conidia formed on stromata to germinate and initiate infection of new seedlings was tested. After 3 mo 20% endophyte-free seedlings became infected by E. gansuensis, whereas the control group showed no endophyte infection. The results indicated the potential of cultures from conidia to mediate horizontal transmission.

  9. Horizontal transmission of nervous necrosis virus between turbot Scophthalmus maximus and Atlantic cod Gadus morhua using cohabitation challenge.

    Science.gov (United States)

    Korsnes, Kjetil; Karlsbakk, Egil; Nylund, Are; Nerland, Audun Helge

    2012-05-15

    Experimental horizontal transmission of nervous necrosis virus (NNV) originating from halibut Hippoglossus hippoglossus was studied through cohabitation of intraperitoneally (i.p.) injected fish with uninfected fish for 125 d. The experimental groups consisted of i.p. injected turbot Scophthalmus maximus or i.p. injected Atlantic salmon Salmo salar with turbot, salmon or Atlantic cod Gadus morhua cohabitants. The initial weights were cod 10 g, salmon 40 g and turbot 3 g. NNV was detected in brain, eye and spleen by real-time reverse transcriptase PCR (qRT-PCR) in cod cohabitated with i.p. injected turbot after 90 and 125 d, suggesting NNV infection was transmitted horizontally from the turbot to cod. NNV was not detected in salmon that were cohabitated with i.p. challenged turbot or salmon. This study shows that NNV strains belonging to the Barfin Flounder Nervous Necrosis Virus (BFNNV) clade may be transmitted from halibut to cod via water. Hence there is a potential risk of horizontal transmission of the virus from farmed halibut to farmed and wild cod. The lack of detection of NNV in cohabitant salmon suggests that this fish species is less susceptible than cod, or not susceptible, to horizontal NNV transmission. This result might be influenced by the size of salmon, viral load in i.p. injected cohabitants or insufficient duration of the experiment.

  10. Assessment of Rice Market Competiveness Using Horizontal Price Transmission: Empirical Evidence from Southern Region of Nigeria

    Directory of Open Access Journals (Sweden)

    S. B. Akpan

    2016-06-01

    Full Text Available The study examined the horizontal price transmission and market integration between the local and foreign rice market in the Southern region of Nigeria. The study used average monthly prices of local and foreign rice in the rural and urban markets from January 2005 to June 2014. The findings show that, prices of local and foreign rice in the rural and urban markets have constant exponential growth rate of 0.60%. The Pearson correlation coefficient revealed a strong positive relationship between prices of local and foreign rice in both rural and urban markets. The cross-product Granger causality test revealed bidirectional relationship between prices of local and foreign rice in the region. The results of the cross co-integration test revealed the presence of co-integration between prices of the two products. The coefficients of the price variable in the cross co-integration equations for the local and foreign rice markets converge to the law of one price which connotes instantaneous price adjustment and competitiveness. The result of the cross - product error correction model also confirmed the existence of the short run market integration between the two markets. The study established the fact that, price of local rice competes favorably with its foreign counter part and thus a perfect substitute especially in the rural area. Based on the finding, it is recommended that, short term policies should be used to intervene in the rice sub sector in the region. Policies aimed at boosting local production of rice should be encouraged, while value additions in the domestic produced rice should be pursuit vigorously.

  11. Safety evaluation of a recombinant myxoma-RHDV virus inducing horizontal transmissible protection against myxomatosis and rabbit haemorrhagic disease.

    Science.gov (United States)

    Torres, J M; Ramírez, M A; Morales, M; Bárcena, J; Vázquez, B; Espuña, E; Pagès-Manté, A; Sánchez-Vizcaíno, J M

    2000-09-15

    We have recently developed a transmissible vaccine to immunize rabbits against myxomatosis and rabbit haemorrhagic disease based on a recombinant myxoma virus (MV) expressing the rabbit haemorrhagic disease virus (RHDV) capsid protein [Bárcena et al. Horizontal transmissible protection against myxomatosis and rabbit haemorragic disease using a recombinant myxoma virus. J. Virol. 2000;74:1114-23]. Administration of the recombinant virus protects rabbits against lethal RHDV and MV challenges. Furthermore, the recombinant virus is capable of horizontal spreading promoting protection of contact animals, thus providing the opportunity to immunize wild rabbit populations. However, potential risks must be extensively evaluated before considering its field use. In this study several safety issues concerning the proposed vaccine have been evaluated under laboratory conditions. Results indicated that vaccine administration is safe even at a 100-fold overdose. No undesirable effects were detected upon administration to immunosuppressed or pregnant rabbits. The recombinant virus maintained its attenuated phenotype after 10 passages in vivo.

  12. Potencial de risco da transmissão transfusional da doença de Chagas em Belo Horizonte (MG

    Directory of Open Access Journals (Sweden)

    Elisabeth Bronfen

    1988-03-01

    Full Text Available Com o objetivo de se isolar amostras do Trypanosoma cruzi de chagásicos crônicos, foram submetidos a xenodiagnóstico e hemocultura, 59 pacientes provenientes do ambulatório de um dos Hospitais de Belo Horizonte. Esses pacientes informaram, em entrevista prévia, serem ou terem sido doadores de sangue ou candidatos à uma primeira doação. 44 deles (74,6% já haviam doado sangue de la mais de 20 vezes em diferentes bancos de sangue de Belo Horizonte. O resultado conferido através da realização concomitante de apenas 1 xenodiagnóstico e 1 hemocultura, revelou, no grupo de doadores, 47,7% depositividade parasitológica. Considerando todos os doadores chagásicos crônicos, parasitologicamente comprovados ou não, ocorreram mais de 112 doações. Esse é um dado altamente significativo em relação ao problema de transmissão transfusional da doença de Chagas em bancos de sangue de Belo Horizonte, MG.Fifty nine chronic chagasic individuals from a out-patient clinics in Belo Horizonte, who use to act as blood donors were submitted to xenodiagnosis and hemocultures for isolating Trypanosoma cruzi. Forty four of them (74.5% had already given blood 1 to 20 times. The results, based on only one xenodiagnosis and one blood culture per patient revealed 47. 7% of parasitological positivity. The whole population studied wes responsible for 112 donations. These data stress the importance of transmission of Chagas disease through blood transfusion in Belo Horizonte.

  13. Sex, horizontal transmission, and multiple hosts prevent local adaptation of Crithidia bombi, a parasite of bumblebees (Bombus spp.).

    Science.gov (United States)

    Erler, Silvio; Popp, Mario; Wolf, Stephan; Lattorff, H Michael G

    2012-05-01

    Local adaptation within host-parasite systems can evolve by several non-exclusive drivers (e.g., host species-genetic adaptation; ecological conditions-ecological adaptation, and time-temporal adaptation). Social insects, especially bumblebees, with an annual colony life history not only provide an ideal system to test parasite transmission within and between different host colonies, but also parasite adaptation to specific host species and environments. Here, we study local adaptation in a multiple-host parasite characterized by high levels of horizontal transmission. Crithidia bombi occurs as a gut parasite in several bumblebee species. Parasites were sampled from five different host species in two subsequent years. Population genetic tools were used to test for the several types of adaptation. Although we found no evidence for local adaptation of the parasite toward host species, there was a slight temporal differentiation of the parasite populations, which might have resulted from severe bottlenecks during queen hibernation. Parasite populations were in Hardy-Weinberg equilibrium and showed no signs of linkage disequilibrium suggesting that sexual reproduction is an alternative strategy in this otherwise clonal parasite. Moreover, high levels of multiple infections were found, which might facilitate sexual genetic exchange. The detection of identical clones in different host species suggested that horizontal transmission occurs between host species and underpins the lack of host-specific adaptation.

  14. Synaptic transmission from horizontal cells to cones is impaired by loss of connexin hemichannels

    NARCIS (Netherlands)

    Klaassen, L.J.; Sun, Z.; Steijaert, M.N.; Bolte, P.; Fahrenfort, I.; Sjoerdsma, T.; Klooster, J.; Claassen, Y.; Shields, C.R.; ten Eikelder, H.M.M.; Janssen-Bienhold, U.; Zoidl, G.; McMahon, D.G.; Kamermans, M.

    2011-01-01

    In the vertebrate retina, horizontal cells generate the inhibitory surround of bipolar cells, an essential step in contrast enhancement. For the last decades, the mechanism involved in this inhibitory synaptic pathway has been a major controversy in retinal research. One hypothesis suggests that con

  15. Potencial de risco da transmissão transfusional da doença de Chagas em Belo Horizonte (MG

    Directory of Open Access Journals (Sweden)

    Elisabeth Bronfen

    1988-03-01

    Full Text Available Com o objetivo de se isolar amostras do Trypanosoma cruzi de chagásicos crônicos, foram submetidos a xenodiagnóstico e hemocultura, 59 pacientes provenientes do ambulatório de um dos Hospitais de Belo Horizonte. Esses pacientes informaram, em entrevista prévia, serem ou terem sido doadores de sangue ou candidatos à uma primeira doação. 44 deles (74,6% já haviam doado sangue de la mais de 20 vezes em diferentes bancos de sangue de Belo Horizonte. O resultado conferido através da realização concomitante de apenas 1 xenodiagnóstico e 1 hemocultura, revelou, no grupo de doadores, 47,7% depositividade parasitológica. Considerando todos os doadores chagásicos crônicos, parasitologicamente comprovados ou não, ocorreram mais de 112 doações. Esse é um dado altamente significativo em relação ao problema de transmissão transfusional da doença de Chagas em bancos de sangue de Belo Horizonte, MG.

  16. Tropical tephritid fruit fly community with high incidence of shared Wolbachia strains as platform for horizontal transmission of endosymbionts.

    Science.gov (United States)

    Morrow, J L; Frommer, M; Shearman, D C A; Riegler, M

    2014-12-01

    Wolbachia are endosymbiotic bacteria that infect 40-65% of arthropod species. They are primarily maternally inherited with occasional horizontal transmission for which limited direct ecological evidence exists. We detected Wolbachia in 8 out of 24 Australian tephritid species. Here, we have used multilocus sequence typing (MLST) to further characterize these Wolbachia strains, plus a novel quantitative polymerase chain reaction method for allele assignment in multiple infections. Based on five MLST loci and the Wolbachia surface protein gene (wsp), five Bactrocera and one Dacus species harboured two identical strains as double infections; furthermore, Bactrocera neohumeralis harboured both of these as single or double infections, and sibling species B. tryoni harboured one. Two Bactrocera species contained Wolbachia pseudogenes, potentially within the fruit fly genomes. A fruit fly parasitoid, Fopius arisanus shared identical alleles with two Wolbachia strains detected in one B. frauenfeldi individual. We report an unprecedented high incidence of four shared Wolbachia strains in eight host species from two trophic levels. This suggests frequent exposure to Wolbachia in this tropical tephritid community that shares host plant and parasitoid species, and also includes species that hybridize. Such insect communities may act as horizontal transmission platforms that contribute to the ubiquity of the otherwise maternally inherited Wolbachia.

  17. Quantitative assessment of the probability of bluetongue virus overwintering by horizontal transmission: application to Germany

    Directory of Open Access Journals (Sweden)

    Napp Sebastian

    2011-01-01

    Full Text Available Abstract Even though bluetongue virus (BTV transmission is apparently interrupted during winter, bluetongue outbreaks often reappear in the next season (overwintering. Several mechanisms for BTV overwintering have been proposed, but to date, their relative importance remain unclear. In order to assess the probability of BTV overwintering by persistence in adult vectors, ruminants (through prolonged viraemia or a combination of both, a quantitative risk assessment model was developed. Furthermore, the model allowed the role played by the residual number of vectors present during winter to be examined, and the effect of a proportion of Culicoides living inside buildings (endophilic behaviour to be explored. The model was then applied to a real scenario: overwintering in Germany between 2006 and 2007. The results showed that the limited number of vectors active during winter seemed to allow the transmission of BTV during this period, and that while transmission was favoured by the endophilic behaviour of some Culicoides, its effect was limited. Even though transmission was possible, the likelihood of BTV overwintering by the mechanisms studied seemed too low to explain the observed re-emergence of the disease. Therefore, other overwintering mechanisms not considered in the model are likely to have played a significant role in BTV overwintering in Germany between 2006 and 2007.

  18. Horizontal transmission of Candida albicans and evidence of a vaccine response in mice colonized with the fungus.

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    Jim E Cutler

    Full Text Available Disseminated candidiasis is the third leading nosocomial blood stream infection in the United States and is often fatal. We previously showed that disseminated candidiasis was preventable in normal mice by immunization with either a glycopeptide or a peptide synthetic vaccine, both of which were Candida albicans cell wall derived. A weakness of these studies is that, unlike humans, mice do not have a C. albicans GI flora and they lack Candida serum antibodies. We examined the influence of C. albicans GI tract colonization and serum antibodies on mouse vaccination responses to the peptide, Fba, derived from fructose bisphosphate aldolase which has cytosolic and cell wall distributions in the fungus. We evaluated the effect of live C. albicans in drinking water and antimicrobial agents on establishment of Candida colonization of the mouse GI tract. Body mass, C. albicans in feces, and fungal-specific serum antibodies were monitored longitudinally. Unexpectedly, C. albicans colonization occurred in mice that received only antibiotics in their drinking water, provided that the mice were housed in the same room as intentionally colonized mice. The fungal strain in unintentionally colonized mice appeared identical to the strain used for intentional GI-tract colonization. This is the first report of horizontal transmission and spontaneous C. albicans colonization in mice. Importantly, many Candida-colonized mice developed serum fungal-specific antibodies. Despite the GI-tract colonization and presence of serum antibodies, the animals made antibodies in response to the Fba immunogen. This mouse model has potential for elucidating C. albicans horizontal transmission and for exploring factors that induce host defense against disseminated candidiasis. Furthermore, a combined protracted GI-tract colonization with Candida and the possibility of serum antibody responses to the presence of the fungus makes this an attractive mouse model for testing the

  19. Horizontal Transmission of the Entomopathogen Fungus Metarhizium anisopliae in Microcerotermes diversus Groups.

    Science.gov (United States)

    Cheraghi, Amir; Habibpour, Behzad; Mossadegh, Mohammad Saied; Sharififard, Mona

    2012-08-08

    An experiment was carried out in order to investigate fungal conidia transmission of Metarhizium anisopliae (Metschnikoff) Sorokin from vector (donor) to healthy Microcerotermes diversus Silvestri (Iso.: Termitidae) and determine the best donor/concentration ratio for transmission. After preliminary trials, concentrations of 3.1 × 10⁴, 3.9 × 10⁵, 3.2 × 10⁶ and 3.5 × 10(8) conidia mL(-1) were selected for testing. The experiment was performed at three donor : Recipient ratios of 10, 30 and 50%. The highest mortality of recipient workers was observed after 14 days at the concentration of 3.5 × 10⁸ conidia mL(-1) and donor ratio of 50%. The mortality of recipient workers was less than 20% at all concentrations at a donor ratio of 10%. Our observations indicate social behavior of M. diversus, such as grooming, can be effective in promoting epizootic outbreaks in a colony. While the current results suggest good potential for efficacy, the use of M. anisopliae as a component of integrated pest management of M. diversus still needs to be proven under field conditions.

  20. Inheritance patterns of secondary symbionts during sexual reproduction of pea aphid biotypes.

    Science.gov (United States)

    Peccoud, Jean; Bonhomme, Joël; Mahéo, Frédérique; de la Huerta, Manon; Cosson, Olivier; Simon, Jean-Christophe

    2014-06-01

    Herbivorous insects frequently harbor bacterial symbionts that affect their ecology and evolution. Aphids host the obligatory endosymbiont Buchnera, which is required for reproduction, together with facultative symbionts whose frequencies vary across aphid populations. These maternally transmitted secondary symbionts have been particularly studied in the pea aphid, Acyrthosiphon pisum, which harbors at least 8 distinct bacterial species (not counting Buchnera) having environmentally dependent effects on host fitness. In particular, these symbiont species are associated with pea aphid populations feeding on specific plants. Although they are maternally inherited, these bacteria are occasionally transferred across insect lineages. One mechanism of such nonmaternal transfer is paternal transmission to the progeny during sexual reproduction. To date, transmission of secondary symbionts during sexual reproduction of aphids has been investigated in only a handful of aphid lineages and 3 symbiont species. To better characterize this process, we investigated inheritance patterns of 7 symbiont species during sexual reproduction of pea aphids through a crossing experiment involving 49 clones belonging to 9 host-specialized biotypes, and 117 crosses. Symbiont species in the progeny were detected with diagnostic qualitative PCR at the fundatrix stage hatching from eggs and in later parthenogenetic generations. We found no confirmed case of paternal transmission of symbionts to the progeny, and we observed that maternal transmission of a particular symbiont species (Serratia symbiotica) was quite inefficient. We discuss these observations in respect to the ecology of the pea aphid.

  1. Environmental factors shape the community of symbionts in the hoopoe uropygial gland more than genetic factors.

    Science.gov (United States)

    Ruiz-Rodríguez, Magdalena; Soler, Juan J; Martín-Vivaldi, Manuel; Martín-Platero, Antonio M; Méndez, María; Peralta-Sánchez, Juan M; Ananou, Samir; Valdivia, Eva; Martínez-Bueno, Manuel

    2014-11-01

    Exploring processes of coevolution of microorganisms and their hosts is a new imperative for life sciences. If bacteria protect hosts against pathogens, mechanisms facilitating the intergenerational transmission of such bacteria will be strongly selected by evolution. By disentangling the diversity of bacterial strains from the uropygium of hoopoes (Upupa epops) due to genetic relatedness or to a common environment, we explored the importance of horizontal (from the environment) and vertical (from parents) acquisition of antimicrobial-producing symbionts in this species. For this purpose, we compared bacterial communities among individuals in nonmanipulated nests; we also performed a cross-fostering experiment using recently hatched nestlings before uropygial gland development and some nestlings that were reared outside hoopoe nests. The capacity of individuals to acquire microbial symbionts horizontally during their development was supported by our results, since cross-fostered nestlings share bacterial strains with foster siblings and nestlings that were not in contact with hoopoe adults or nests also developed the symbiosis. Moreover, nestlings could change some bacterial strains over the course of their stay in the nest, and adult females changed their bacterial community in different years. However, a low rate of vertical transmission was inferred, since genetic siblings reared in different nests shared more bacterial strains than they shared with unrelated nestlings raised in different nests. In conclusion, hoopoes are able to incorporate new symbionts from the environment during the development of the uropygium, which could be a selective advantage if strains with higher antimicrobial capacity are incorporated into the gland and could aid hosts in fighting against pathogenic and disease-causing microbes.

  2. Environmental Factors Shape the Community of Symbionts in the Hoopoe Uropygial Gland More than Genetic Factors

    Science.gov (United States)

    Soler, Juan J.; Martín-Vivaldi, Manuel; Martín-Platero, Antonio M.; Méndez, María; Peralta-Sánchez, Juan M.; Ananou, Samir; Valdivia, Eva; Martínez-Bueno, Manuel

    2014-01-01

    Exploring processes of coevolution of microorganisms and their hosts is a new imperative for life sciences. If bacteria protect hosts against pathogens, mechanisms facilitating the intergenerational transmission of such bacteria will be strongly selected by evolution. By disentangling the diversity of bacterial strains from the uropygium of hoopoes (Upupa epops) due to genetic relatedness or to a common environment, we explored the importance of horizontal (from the environment) and vertical (from parents) acquisition of antimicrobial-producing symbionts in this species. For this purpose, we compared bacterial communities among individuals in nonmanipulated nests; we also performed a cross-fostering experiment using recently hatched nestlings before uropygial gland development and some nestlings that were reared outside hoopoe nests. The capacity of individuals to acquire microbial symbionts horizontally during their development was supported by our results, since cross-fostered nestlings share bacterial strains with foster siblings and nestlings that were not in contact with hoopoe adults or nests also developed the symbiosis. Moreover, nestlings could change some bacterial strains over the course of their stay in the nest, and adult females changed their bacterial community in different years. However, a low rate of vertical transmission was inferred, since genetic siblings reared in different nests shared more bacterial strains than they shared with unrelated nestlings raised in different nests. In conclusion, hoopoes are able to incorporate new symbionts from the environment during the development of the uropygium, which could be a selective advantage if strains with higher antimicrobial capacity are incorporated into the gland and could aid hosts in fighting against pathogenic and disease-causing microbes. PMID:25172851

  3. Experimental infection and horizontal transmission of Bartonella henselae in domestic cats

    Directory of Open Access Journals (Sweden)

    ZANUTTO Marcelo de Souza

    2001-01-01

    Full Text Available In order to study B. henselae transmission among cats, five young cats were kept in confinement for two years, one of them being inoculated by SC route with B. henselae (10(5 UFC. Only occasional contact among cats occurred but the presence of fleas was observed in all animals throughout the period. Blood culture for isolation of bacteria, PCR-HSP and FTSZ (gender specific, and BH-PCR (species-specific, as well as indirect immunofluorescence method for anti-B. henselae antibodies were performed to confirm the infection of the inoculated cat as well as the other naive cats. Considering the inoculated animal, B. henselae was first isolated by blood culture two months after inoculation, bacteremia last for four months, the specific antibodies being detected by IFI during the entire period. All contacting animals presented with bacteremia 6 months after experimental inoculation but IFI did not detect seroconversion in these animals. All the isolates from these cats were characterized as Bartonella (HSP and FTSZ-PCR, henselae (BH-PCR. However, DNA of B. henselae could not be amplified directly from peripheral blood by the PCR protocols used. Isolation of bacteria by blood culture was the most efficient method to diagnose infection compared to PCR or IFI. The role of fleas in the epidemiology of B. henselae infection in cats is discussed.

  4. Direct evidence for maternal inheritance of bacterial symbionts in small deep-sea clams (Bivalvia: Vesicomyidae)

    Science.gov (United States)

    Szafranski, Kamil M.; Gaudron, Sylvie M.; Duperron, Sébastien

    2014-05-01

    Bacterial symbiont transmission is a key step in the renewal of the symbiotic interaction at each host generation, and different modes of transmission can be distinguished. Vesicomyidae are chemosynthetic bivalves from reducing habitats that rely on symbiosis with sulfur-oxidizing bacteria, in which two studies suggesting vertical transmission of symbionts have been published, both limited by the imaging techniques used. Using fluorescence in situ hybridization and transmission electron microscopy, we demonstrate that bacterial symbionts of Isorropodon bigoti, a gonochoristic Vesicomyidae from the Guiness cold seep site, occur intracellularly within female gametes at all stages of gametogenesis from germ cells to mature oocytes and in early postlarval stage. Symbionts are completely absent from the male gonad and gametes. This study confirms the transovarial transmission of symbionts in Vesicomyidae and extends it to the smaller species for which no data were previously available.

  5. Ontogenetic changes in the bacterial symbiont community of the tropical demosponge Amphimedon queenslandica: metamorphosis is a new beginning

    Directory of Open Access Journals (Sweden)

    Rebecca A Fieth

    2016-11-01

    Full Text Available Vertical transmission of bacterial symbionts, which is known in many species of sponge (Porifera, is expected to promote strong fidelity between the partners. Combining 16S rRNA gene amplicon sequencing and electron microscopy, we have assayed the relative abundance of vertically-inherited bacterial symbionts in several stages of the life cycle of Amphimedon queenslandica, a tropical coral reef sponge. We reveal that adult A. queenslandica house a low diversity microbiome dominated by just three proteobacterial OTUs, with a single gammaprotebacterium clearly dominant through much of the life cycle. This ontogenetic perspective has revealed that, although vertical transmission occurs very early in development, the inherited symbionts do not maintain proportional dominance of the bacterial community at every developmental stage. A reproductive bottleneck in the A. queenslandica life cycle is larval settlement, when a free-swimming pelagic larva settles out of the water column onto the benthos and completes metamorphoses into the sessile body plan within just 3 to 4 days. During this dramatic life cycle transition, an influx of environmentally-derived bacteria leads to a major reorganization of the microbiome, potentially challenging the fidelity and persistence of the vertically-inherited symbiotic relationships. However, dominance of the primary, vertically-inherited symbionts is restored in adult sponges. The mechanisms underlying ontogenetic changes in the bacterial community are unknown, including how the dominance of the primary symbionts is restored in the adult sponge – does the host or symbiont regulate this process? Using high-resolution transcriptional profiling in multiple stages of the A. queenslandica life cycle combined with this natural perturbation of the microbiome immediately following larval settlement, we are beginning to identify candidate host genes associated with animal-bacterial crosstalk. Among the sponge host genes

  6. HEPATITIS B VIRUS DNA IN SALIVA FROM CHILDREN WITH CHRONIC HEPATITIS B INFECTION IMPLICATIONS FOR SALIVA AS A POTENTIAL MODE OF HORIZONTAL TRANSMISSION

    NARCIS (Netherlands)

    Heiberg, Ida Louise; Hoegh, Mette; Ladelund, Steen; Niesters, Hubert G. M.; Hogh, Birthe

    2010-01-01

    To explore the mechanism of horizontal transmission of hepatitis B virus (HBV) among children, we investigated the quantitative relationship between HBV in saliva and blood from 46 children with chronic hepatitis B. We found high levels of HBV DNA in saliva of HBeAg (+) children, suggesting saliva

  7. HEPATITIS B VIRUS DNA IN SALIVA FROM CHILDREN WITH CHRONIC HEPATITIS B INFECTION IMPLICATIONS FOR SALIVA AS A POTENTIAL MODE OF HORIZONTAL TRANSMISSION

    NARCIS (Netherlands)

    Heiberg, Ida Louise; Hoegh, Mette; Ladelund, Steen; Niesters, Hubert G. M.; Hogh, Birthe

    2010-01-01

    To explore the mechanism of horizontal transmission of hepatitis B virus (HBV) among children, we investigated the quantitative relationship between HBV in saliva and blood from 46 children with chronic hepatitis B. We found high levels of HBV DNA in saliva of HBeAg (+) children, suggesting saliva a

  8. HEPATITIS B VIRUS DNA IN SALIVA FROM CHILDREN WITH CHRONIC HEPATITIS B INFECTION IMPLICATIONS FOR SALIVA AS A POTENTIAL MODE OF HORIZONTAL TRANSMISSION

    NARCIS (Netherlands)

    Heiberg, Ida Louise; Hoegh, Mette; Ladelund, Steen; Niesters, Hubert G. M.; Hogh, Birthe

    2010-01-01

    To explore the mechanism of horizontal transmission of hepatitis B virus (HBV) among children, we investigated the quantitative relationship between HBV in saliva and blood from 46 children with chronic hepatitis B. We found high levels of HBV DNA in saliva of HBeAg (+) children, suggesting saliva a

  9. Hepatitis B virus DNA in saliva from children with chronic hepatitis B infection: implications for saliva as a potential mode of horizontal transmission

    DEFF Research Database (Denmark)

    Heiberg, Ida Louise; Hoegh, Mette; Ladelund, Steen

    2010-01-01

    To explore the mechanism of horizontal transmission of hepatitis B virus (HBV) among children, we investigated the quantitative relationship between HBV in saliva and blood from 46 children with chronic hepatitis B. We found high levels of HBV DNA in saliva of HBeAg (+) children, suggesting saliva...

  10. Molecular evidence for host-symbiont specificity in soritid foraminifera.

    Science.gov (United States)

    Garcia-Cuetos, Lydia; Pochon, Xavier; Pawlowski, Jan

    2005-12-01

    Symbiosis between the dinoflagellate genus Symbiodinium and various invertebrates and protists is an ubiquitous phenomenon in shallow tropical and subtropical waters. Molecular studies undertaken on cnidarian symbionts revealed the presence of several distinctive lineages or subgeneric clades of Symbiodinium whose taxonomic level provides limited information about the specificity between invertebrate hosts and their symbionts. This contrasts with the finding of several Symbiodinium clades being present almost exclusively in foraminifera and belonging to the subfamily Soritinae. To test whether such specificity also exists at a lower taxonomic level within Soritinae, we obtained the SSU rDNA sequences from 159 soritid individuals collected in nine localities worldwide and representing all known morphospecies of this subfamily. For each individual, the symbionts were determined either by sequencing or by RFLP analysis. We distinguished 22 phylotypes of Soritinae in relation with a number of symbiont "groups" corresponding to 3 clades and 5 subclades of Symbiodinium. Among the 22 soritid phylotypes, 14 show strict symbiont specificity and only one was found to be a host for more than two "groups" of Symbiodinium. It is suggested that the strong host-symbiont specificity observed in Soritinae is a combined effect of a selective recognition mechanism, vertical transmission of symbionts, and biogeographical isolation.

  11. Presença de animais associada ao risco de transmissão da leishmaniose visceral em humanos em Belo Horizonte, Minas Gerais Animal presence and the risk for transmission of visceral leishmaniasis in Belo Horizonte, Brazil

    Directory of Open Access Journals (Sweden)

    B.K.A. Borges

    2009-10-01

    Full Text Available Analisou-se o risco de se contrair leishmaniose visceral (LV e a presença de animais em residências de Belo Horizonte/MG, em 2006. O estudo de caso-controle foi feito por meio de visitas domiciliares, aplicação de questionário e registro de imagens da residência. A estimativa de risco foi mensurada por comparação de condições de moradia entre dois grupos: 1- constituído por 82 casos humanos de LV ocorridos em 2004 e 2- 164 controles (vizinhos dos casos. Os domicílios pertencentes ao grupo 1 foram os que apresentaram os maiores percentuais de presença de animais. Observou-se, pela análise univariada, que a presença de patos, roedores, pássaros e galinhas aumenta o risco de ocorrer LV em 4,18; 1,81; 1,57; e 1,47 vezes, respectivamente. Para os proprietários de cães, o aumento no risco de contrair LV é equivalente a 2,17 vezes e está relacionado ao número de cães no domicílio. O risco de contrair LV é maior 1,87 vezes para moradores com um cão e 3,36 vezes para moradores com dois cães, quando comparados a pessoas que não possuem esses animais.This study evaluated the animal presence in dwellings and the risk for transmission of visceral leishmaniasis (VL in Belo Horizonte, Brazil, 2006. A case-control study was conducted by means of dwelling visits, direct interviews, and image register in the houses. The risk estimates were produced comparing the dwelling condition between two groups: 1 82 human cases of VL recorded in 2004; and 2 164 controls (neighbors of the first. The cases presented a higher proportion in the animal presence compared to controls. Using an unconditional logistic regression, it was selected the presence of ducks with an OR of 4.18 (CI 95% - 0.74 to 23.32; rodents with an OR of 1.81 (CI 95% - 0.96 to 3.39; birds with an OR of 1.56 (CI 95% - 0.90 to 2.69, and chicken with an OR of 1.47 (CI 95% - 0.74 to 2.90. The owners of dogs were 2.17 more likely to have VL than those who did not have dogs, and this

  12. Population dynamics of defensive symbionts in aphids

    National Research Council Canada - National Science Library

    Kerry M Oliver; Jaime Campos; Nancy A Moran; Martha S Hunter

    2008-01-01

    .... While laboratory studies have identified diverse beneficial effects conferred by inherited symbionts of insects, they have not explicitly examined the population dynamics of mutualist symbiont...

  13. Endozoicomonas Are Specific, Facultative Symbionts of Sea Squirts

    Science.gov (United States)

    Schreiber, Lars; Kjeldsen, Kasper U.; Funch, Peter; Jensen, Jeppe; Obst, Matthias; López-Legentil, Susanna; Schramm, Andreas

    2016-01-01

    Ascidians are marine filter feeders and harbor diverse microbiota that can exhibit a high degree of host-specificity. Pharyngeal samples of Scandinavian and Mediterranean ascidians were screened for consistently associated bacteria by culture-dependent and -independent approaches. Representatives of the Endozoicomonas (Gammaproteobacteria, Hahellaceae) clade were detected in the ascidian species Ascidiella aspersa, Ascidiella scabra, Botryllus schlosseri, Ciona intestinalis, Styela clava, and multiple Ascidia/Ascidiella spp. In total, Endozoicomonas was detected in more than half of all specimens screened, and in 25–100% of the specimens for each species. The retrieved Endozoicomonas 16S rRNA gene sequences formed an ascidian-specific subclade, whose members were detected by fluorescence in situ hybridization (FISH) as extracellular microcolonies in the pharynx. Two strains of the ascidian-specific Endozoicomonas subclade were isolated in pure culture and characterized. Both strains are chemoorganoheterotrophs and grow on mucin (a mucus glycoprotein). The strains tested negative for cytotoxic or antibacterial activity. Based on these observations, we propose ascidian-associated Endozoicomonas to be commensals, living off the mucus continuously secreted into the pharynx. Members of the ascidian-specific Endozoicomonas subclade were also detected in seawater from the Scandinavian sampling site, which suggests acquisition of the symbionts by horizontal transmission. The combined results indicate a host-specific, yet facultative symbiosis between ascidians and Endozoicomonas. PMID:27462299

  14. Insect symbionts in food webs

    Science.gov (United States)

    Henry, Lee M.

    2016-01-01

    Recent research has shown that the bacterial endosymbionts of insects are abundant and diverse, and that they have numerous different effects on their hosts' biology. Here we explore how insect endosymbionts might affect the structure and dynamics of insect communities. Using the obligate and facultative symbionts of aphids as an example, we find that there are multiple ways that symbiont presence might affect food web structure. Many symbionts are now known to help their hosts escape or resist natural enemy attack, and others can allow their hosts to withstand abiotic stress or affect host plant use. In addition to the direct effect of symbionts on aphid phenotypes there may be indirect effects mediated through trophic and non-trophic community interactions. We believe that by using data from barcoding studies to identify bacterial symbionts, this extra, microbial dimension to insect food webs can be better elucidated. This article is part of the themed issue ‘From DNA barcodes to biomes’. PMID:27481779

  15. Host-symbiont co-speciation and reductive genome evolution in gut symbiotic bacteria of acanthosomatid stinkbugs

    Directory of Open Access Journals (Sweden)

    Kamagata Yoichi

    2009-01-01

    Full Text Available Abstract Background Host-symbiont co-speciation and reductive genome evolution have been commonly observed among obligate endocellular insect symbionts, while such examples have rarely been identified among extracellular ones, the only case reported being from gut symbiotic bacteria of stinkbugs of the family Plataspidae. Considering that gut symbiotic communities are vulnerable to invasion of foreign microbes, gut symbiotic associations have been thought to be evolutionarily not stable. Stinkbugs of the family Acanthosomatidae harbor a bacterial symbiont in the midgut crypts, the lumen of which is completely sealed off from the midgut main tract, thereby retaining the symbiont in the isolated cryptic cavities. We investigated histological, ecological, phylogenetic, and genomic aspects of the unique gut symbiosis of the acanthosomatid stinkbugs. Results Phylogenetic analyses showed that the acanthosomatid symbionts constitute a distinct clade in the γ-Proteobacteria, whose sister groups are the obligate endocellular symbionts of aphids Buchnera and the obligate gut symbionts of plataspid stinkbugs Ishikawaella. In addition to the midgut crypts, the symbionts were located in a pair of peculiar lubricating organs associated with the female ovipositor, by which the symbionts are vertically transmitted via egg surface contamination. The symbionts were detected not from ovaries but from deposited eggs, and surface sterilization of eggs resulted in symbiont-free hatchlings. The symbiont-free insects suffered retarded growth, high mortality, and abnormal morphology, suggesting important biological roles of the symbiont for the host insects. The symbiont phylogeny was generally concordant with the host phylogeny, indicating host-symbiont co-speciation over evolutionary time despite the extracellular association. Meanwhile, some local host-symbiont phylogenetic discrepancies were found, suggesting occasional horizontal symbiont transfers across the host

  16. Host-symbiont co-speciation and reductive genome evolution in gut symbiotic bacteria of acanthosomatid stinkbugs.

    Science.gov (United States)

    Kikuchi, Yoshitomo; Hosokawa, Takahiro; Nikoh, Naruo; Meng, Xian-Ying; Kamagata, Yoichi; Fukatsu, Takema

    2009-01-15

    Host-symbiont co-speciation and reductive genome evolution have been commonly observed among obligate endocellular insect symbionts, while such examples have rarely been identified among extracellular ones, the only case reported being from gut symbiotic bacteria of stinkbugs of the family Plataspidae. Considering that gut symbiotic communities are vulnerable to invasion of foreign microbes, gut symbiotic associations have been thought to be evolutionarily not stable. Stinkbugs of the family Acanthosomatidae harbor a bacterial symbiont in the midgut crypts, the lumen of which is completely sealed off from the midgut main tract, thereby retaining the symbiont in the isolated cryptic cavities. We investigated histological, ecological, phylogenetic, and genomic aspects of the unique gut symbiosis of the acanthosomatid stinkbugs. Phylogenetic analyses showed that the acanthosomatid symbionts constitute a distinct clade in the gamma-Proteobacteria, whose sister groups are the obligate endocellular symbionts of aphids Buchnera and the obligate gut symbionts of plataspid stinkbugs Ishikawaella. In addition to the midgut crypts, the symbionts were located in a pair of peculiar lubricating organs associated with the female ovipositor, by which the symbionts are vertically transmitted via egg surface contamination. The symbionts were detected not from ovaries but from deposited eggs, and surface sterilization of eggs resulted in symbiont-free hatchlings. The symbiont-free insects suffered retarded growth, high mortality, and abnormal morphology, suggesting important biological roles of the symbiont for the host insects. The symbiont phylogeny was generally concordant with the host phylogeny, indicating host-symbiont co-speciation over evolutionary time despite the extracellular association. Meanwhile, some local host-symbiont phylogenetic discrepancies were found, suggesting occasional horizontal symbiont transfers across the host lineages. The symbionts exhibited AT

  17. Caste-specific symbiont policing by workers of Acromyrmex fungus-growing ants

    DEFF Research Database (Denmark)

    Ivens, Aniek B.F.; Nash, David R.; Poulsen, Michael

    2009-01-01

    The interaction between leaf-cutting ants and their fungus garden mutualists is ideal for studying the evolutionary stability of interspecific cooperation. Although the mutualism has a long history of diffuse coevolution, there is ample potential for conflicts between the partners over the mixing...... and transmission of symbionts. Symbiont transmission is vertical by default, and both the ants and resident fungus actively protect the fungal monoculture growing in their nest against secondary introductions of genetically dissimilar symbionts from other colonies. An earlier study showed that mixtures of major...

  18. Caste-specific symbiont policing by workers of Acromyrmex fungus-growing ants

    DEFF Research Database (Denmark)

    Ivens, Aniek B.F.; Nash, David R.; Poulsen, Michael;

    2009-01-01

    The interaction between leaf-cutting ants and their fungus garden mutualists is ideal for studying the evolutionary stability of interspecific cooperation. Although the mutualism has a long history of diffuse coevolution, there is ample potential for conflicts between the partners over the mixing...... and transmission of symbionts. Symbiont transmission is vertical by default, and both the ants and resident fungus actively protect the fungal monoculture growing in their nest against secondary introductions of genetically dissimilar symbionts from other colonies. An earlier study showed that mixtures of major...

  19. Horizontal transmission dynamics of White spot syndrome virus by cohabitation trials in juvenile Penaeus monodon and P. vannamei.

    Science.gov (United States)

    Tuyen, N X; Verreth, J; Vlak, J M; de Jong, M C M

    2014-11-01

    White spot syndrome virus (WSSV), a rod-shaped double-stranded DNA virus, is an infectious agent causing fatal disease in shrimp farming around the globe. Within shrimp populations WSSV is transmitted very fast, however, the modes and dynamics of transmission of this virus are not well understood. In the current study the dynamics of disease transmission of WSSV were investigated in small, closed populations of Penaeus monodon and Penaeus vannamei. Pair cohabitation experiments using PCR as a readout for virus infection were used to estimate transmission parameters for WSSV in these two species. The mortality rate of contact-infected shrimp in P. monodon was higher than the rate in P. vannamei. The transmission rate parameters for WSSV were not different between the two species. The relative contribution of direct and indirect transmission rates of WSSV differed between the two species. For P. vannamei the direct contact transmission rate of WSSV was significantly lower than the indirect environmental transmission rate, but for P. monodon, the opposite was found. The reproduction ratio R0 for WSSV for these two species of shrimp was estimated to be above one: 2.07 (95%CI 1.53, 2.79) for P. monodon and 1.51 (95%CI 1.12, 2.03) for P. vannamei. The difference in R0 between the two species is due to a lower host mortality and hence a longer infectious period of WSSV in P. monodon.

  20. Dynamic Acquisition and Loss of Dual-Obligate Symbionts in the Plant-Sap-Feeding Adelgidae (Hemiptera: Sternorrhyncha: Aphidoidea

    Directory of Open Access Journals (Sweden)

    Carol D. von Dohlen

    2017-06-01

    Full Text Available Sap-sucking insects typically engage in obligate relationships with symbiotic bacteria that play nutritional roles in synthesizing nutrients unavailable or in scarce supply from the plant-sap diets of their hosts. Adelgids are sap-sucking insects with complex life cycles that involve alternation between conifer tree species. While all adelgid species feed on spruce during the sexual phase of their life cycle, each adelgid species belongs to a major lineage that feeds on a distinct genus of conifers as their alternate host. Previous work on adelgid symbionts had discovered pairs of symbionts within each host species, and unusual diversity across the insect family, but left several open questions regarding the status of bacterial associates. Here, we explored the consistency of symbionts within and across adelgid lineages, and sought evidence for facultative vs. obligate symbiont status. Representative species were surveyed for symbionts using 16S ribosomal DNA gene sequencing, confirming that different symbiont pairs were consistently present within each major adelgid lineage. Several approaches were used to establish whether symbionts exhibited characteristics of long-term, obligate mutualists. Patterns of symbiont presence across adelgid species and diversification with host insects suggested obligate relationships. Fluorescent in situ hybridization and electron microscopy localized symbionts to bacteriocyte cells within the bacteriome of each species (with one previously known exception, and detection of symbionts in eggs indicated their vertical transmission. Common characteristics of long-term obligate symbionts, such as nucleotide compositional bias and pleomorphic symbiont cell shape were also observed. Superimposing microbial symbionts on the adelgid phylogeny revealed a dynamic pattern of symbiont gains and losses over a relatively short period of time compared to other symbionts associated with sap-sucking insects, with each adelgid

  1. Contribution of the horizontal transmission of the entomopathogenic fungus Beauveria bassiana to the overall performance of a fungal powder formulation against Triatoma infestans

    Directory of Open Access Journals (Sweden)

    Forlani L

    2011-09-01

    Full Text Available Lucas Forlani, Nicolás Pedrini, M Patricia JuárezInstituto de Investigaciones Bioquímicas de La Plata (CCT La Plata CONICET-UNLP, Facultad de Ciencias Médicas, Universidad Nacional de La Plata, La Plata, ArgentinaAbstract: Control of domiciliated Triatoma infestans, the major Chagas disease vector in southern South America, is currently achieved by indoor residual spraying of infested houses with chemical insecticides. However, in recent years this strategy has been threatened by the emergence of pyrethroid-resistant bug populations. As an alternative approach, we have previously demonstrated the efficacy of the entomopathogenic fungus Beauveria bassiana to control T. infestans bugs regardless of their pyrethroid susceptibility. In this work, we tested the virulence and residual activity of a powdered fungal formulation, and studied the significance of the horizontal transmission process (autodissemination to fungal infection of bugs. The B. bassiana-based formulation was highly virulent against all T. infestans stages, and maintained its insecticidal capability for at least 5 months under natural ambient conditions. We showed that horizontal transmission of conidia is associated to bug density, and contributes significantly to the overall population infection event.Keywords: Chagas disease vectors, triatomines, biocontrol, autodissemination

  2. Litter treatment with Aluminum Sulfate (Alum) produced an inconsistent reduction in horizontal transmission of Campylobacter in chickens

    Science.gov (United States)

    Campylobacteriosis is a significant health problem worldwide and poultry products are considered as one of the main vehicles of transmission. Alum treatment of poultry litter was reported to decrease Campylobacter colonization frequency and population in the ceca in broilers. Little is known about h...

  3. Horizontal transmission dynamics of White spot syndrome virus by cohabitation trials in juvenile Penaeus monodon and P. vannamei

    NARCIS (Netherlands)

    Ngo Xuan, T.; Verreth, J.A.J.; Vlak, J.M.; Jong, de M.C.M.

    2014-01-01

    White spot syndrome virus (WSSV), a rod-shaped double-stranded DNA virus, is an infectious agent causing fatal disease in shrimp farming around the globe. Within shrimp populations WSSV is transmitted very fast, however, the modes and dynamics of transmission of this virus are not well understood. I

  4. Lack of Overt Genome Reduction in the Bryostatin-Producing Bryozoan Symbiont "Candidatus Endobugula sertula".

    Science.gov (United States)

    Miller, Ian J; Vanee, Niti; Fong, Stephen S; Lim-Fong, Grace E; Kwan, Jason C

    2016-11-15

    The uncultured bacterial symbiont "Candidatus Endobugula sertula" is known to produce cytotoxic compounds called bryostatins, which protect the larvae of its host, Bugula neritina The symbiont has never been successfully cultured, and it was thought that its genome might be significantly reduced. Here, we took a shotgun metagenomics and metatranscriptomics approach to assemble and characterize the genome of "Ca Endobugula sertula." We found that it had specific metabolic deficiencies in the biosynthesis of certain amino acids but few other signs of genome degradation, such as small size, abundant pseudogenes, and low coding density. We also identified homologs to genes associated with insect pathogenesis in other gammaproteobacteria, and these genes may be involved in host-symbiont interactions and vertical transmission. Metatranscriptomics revealed that these genes were highly expressed in a reproductive host, along with bry genes for the biosynthesis of bryostatins. We identified two new putative bry genes fragmented from the main bry operon, accounting for previously missing enzymatic functions in the pathway. We also determined that a gene previously assigned to the pathway, bryS, is not expressed in reproductive tissue, suggesting that it is not involved in the production of bryostatins. Our findings suggest that "Ca Endobugula sertula" may be able to live outside the host if its metabolic deficiencies are alleviated by medium components, which is consistent with recent findings that it may be possible for "Ca Endobugula sertula" to be transmitted horizontally. The bryostatins are potent protein kinase C activators that have been evaluated in clinical trials for a number of indications, including cancer and Alzheimer's disease. There is, therefore, considerable interest in securing a renewable supply of these compounds, which is currently only possible through aquaculture of Bugula neritina and total chemical synthesis. However, these approaches are labor

  5. Experimental replacement of an obligate insect symbiont.

    Science.gov (United States)

    Moran, Nancy A; Yun, Yueli

    2015-02-17

    Symbiosis, the close association of unrelated organisms, has been pivotal in biological diversification. In the obligate symbioses found in many insect hosts, organisms that were once independent are permanently and intimately associated, resulting in expanded ecological capabilities. The primary model for this kind of symbiosis is the association between the bacterium Buchnera and the pea aphid (Acyrthosiphon pisum). A longstanding obstacle to efforts to illuminate genetic changes underlying obligate symbioses has been the inability to experimentally disrupt and reconstitute symbiont-host partnerships. Our experiments show that Buchnera can be experimentally transferred between aphid matrilines and, furthermore, that Buchnera replacement has a massive effect on host fitness. Using a recipient pea aphid matriline containing Buchnera that are heat sensitive because of an allele eliminating the heat shock response of a small chaperone, we reduced native Buchnera through heat exposure and introduced a genetically distinct Buchnera from another matriline, achieving complete replacement and stable inheritance. This transfer disrupted 100 million years (∼ 1 billion generations) of continuous maternal transmission of Buchnera in its host aphids. Furthermore, aphids with the Buchnera replacement enjoyed a dramatic increase in heat tolerance, directly demonstrating a strong effect of symbiont genotype on host ecology.

  6. Transmission of visceral leishmaniasis in dogs in a risk area of the metropolitan region of Belo Horizonte, Minas Gerais, Brazil

    Directory of Open Access Journals (Sweden)

    E.G.P. Lopes

    Full Text Available ABSTRACT Visceral leishmaniasis (VL has spread rapidly across cities in the metropolitan region of Belo Horizonte. The aim of this study was to investigate VL dynamics in a prospective cohort study of dogs in Juatuba, between 2010 and 2011, to confirm the incidence of Leishmania infantum, and to assess possible risk factors associated with infection. An observational and prospective closed cohort study was performed using serology testing in dogs, randomly selected from the whole municipality. All seronegative dogs, or dogs with inconclusive results were monitored using indirect immunofluorescence (IIF at 6-month intervals. The dog's owners completed a semi-structured questionnaire to assess possible causal factors of seroconversion, and the responses were assessed using logistic regression. The canine incidence coefficient was 206/1,000 dogs per year (CI: 178-238, and a cluster was identified in an area with a high concentration of seropositive dogs, but a low overall canine population. Large dogs were identified as a risk factor and the following variables were identified as protection factors: dogs aged over 4 years, daily peridomicile cleaning, and better socioeconomic conditions. VL is spreading over a large area in Juatuba in a short period of time.

  7. Horizontal Transmission of the Entomopathogen Fungus Metarhizium anisopliae in Microcerotermes diversus Groups

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    Mohammad Saied Mossadegh

    2012-08-01

    Full Text Available An experiment was carried out in order to investigate fungal conidia transmission of Metarhizium anisopliae (Metschnikoff Sorokin from vector (donor to healthy Microcerotermes diversus Silvestri (Iso.: Termitidae and determine the best donor/concentration ratio for transmission. After preliminary trials, concentrations of 3.1 × 104, 3.9 × 105, 3.2 × 106 and 3.5 × 108 conidia mL−1 were selected for testing. The experiment was performed at three donor : Recipient ratios of 10, 30 and 50%. The highest mortality of recipient workers was observed after 14 days at the concentration of 3.5 × 108 conidia mL−1 and donor ratio of 50%. The mortality of recipient workers was less than 20% at all concentrations at a donor ratio of 10%. Our observations indicate social behavior of M. diversus, such as grooming, can be effective in promoting epizootic outbreaks in a colony. While the current results suggest good potential for efficacy, the use of M. anisopliae as a component of integrated pest management of M. diversus still needs to be proven under field conditions.

  8. Symbiosis within Symbiosis: Evolving Nitrogen-Fixing Legume Symbionts.

    Science.gov (United States)

    Remigi, Philippe; Zhu, Jun; Young, J Peter W; Masson-Boivin, Catherine

    2016-01-01

    Bacterial accessory genes are genomic symbionts with an evolutionary history and future that is different from that of their hosts. Packages of accessory genes move from strain to strain and confer important adaptations, such as interaction with eukaryotes. The ability to fix nitrogen with legumes is a remarkable example of a complex trait spread by horizontal transfer of a few key symbiotic genes, converting soil bacteria into legume symbionts. Rhizobia belong to hundreds of species restricted to a dozen genera of the Alphaproteobacteria and Betaproteobacteria, suggesting infrequent successful transfer between genera but frequent successful transfer within genera. Here we review the genetic and environmental conditions and selective forces that have shaped evolution of this complex symbiotic trait. Copyright © 2015 Elsevier Ltd. All rights reserved.

  9. Patterns of interaction specificity of fungus-growing termites and Termitomyces symbionts in South Africa

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    de Beer Z Wilhelm

    2007-07-01

    Full Text Available Abstract Background Termites of the subfamily Macrotermitinae live in a mutualistic symbiosis with basidiomycete fungi of the genus Termitomyces. Here, we explored interaction specificity in fungus-growing termites using samples from 101 colonies in South-Africa and Senegal, belonging to eight species divided over three genera. Knowledge of interaction specificity is important to test the hypothesis that inhabitants (symbionts are taxonomically less diverse than 'exhabitants' (hosts and to test the hypothesis that transmission mode is an important determinant for interaction specificity. Results Analysis of Molecular Variance among symbiont ITS sequences across termite hosts at three hierarchical levels showed that 47 % of the variation occurred between genera, 18 % between species, and the remaining 35 % between colonies within species. Different patterns of specificity were evident. High mutual specificity was found for the single Macrotermes species studied, as M. natalensis was associated with a single unique fungal haplotype. The three species of the genus Odontotermes showed low symbiont specificity: they were all associated with a genetically diverse set of fungal symbionts, but their fungal symbionts showed some host specificity, as none of the fungal haplotypes were shared between the studied Odontotermes species. Finally, bilaterally low specificity was found for the four tentatively recognized species of the genus Microtermes, which shared and apparently freely exchanged a common pool of divergent fungal symbionts. Conclusion Interaction specificity was high at the genus level and generally much lower at the species level. A comparison of the observed diversity among fungal symbionts with the diversity among termite hosts, indicated that the fungal symbiont does not follow the general pattern of an endosymbiont, as we found either similar diversity at both sides or higher diversity in the symbiont. Our results further challenge the

  10. Horizontal Transmission of Metarhizium anisopliae in Fruit Flies and Effect of Fungal Infection on Egg Laying and Fertility

    Directory of Open Access Journals (Sweden)

    Nguya K. Maniania

    2013-05-01

    Full Text Available Fly-to-fly transmission of conidia of the entomopathogenic fungus Metarhizium anisopliae and the effect of fungal infection on the reproductive potential of females surviving infection were investigated in three fruit fly species, Ceratitis cosyra, C. fasciventris, and C. capitata. The number of conidia picked up by a single fruit fly was determined in C. cosyra. The initial uptake (Day 0 of conidia by a single fly was approx. 1.1 × 106 conidia after exposure to the treated substrate. However, the number of conidia dropped from 7.2 × 105 to 4.1 × 105 conidia after 2 and 8 h post-exposure, respectively. The number of conidia picked up by a single fungus-treated fly (“donor” varied between 3.8 × 105 and 1.0 × 106 in the three fruit fly species, resulting in 100% mortality 5–6 days post-exposure. When fungus-free flies of both sexes (“recipient” flies were allowed to mate with “donor” flies, the number of conidia picked up by a single fly varied between 1.0 × 105 and 2.5 × 105, resulting in a mortality of 83–100% in C. capitata, 72–85% in C. cosyra and 71–93% in C. fasciventris 10–15 days post-inoculation. There was an effect of fungal infection on female egg laying in the three species of fruit flies as control flies laid more eggs than fungus-treated females. The percentage reduction in fecundity in flies infected with M. anisopliae was 82, 73 and 37% in C. capitata, C. fasciventris and C. cosyra, respectively. The results are discussed with regard to application in autodissemination techniques.

  11. High Symbiont Relatedness Stabilizes Mutualistic Cooperation in Fungus-Growing Termites

    DEFF Research Database (Denmark)

    Aanen, Duur K; de Fine Licht, Henrik H; Debets, Alfons J M

    2009-01-01

    It is unclear how mutualistic relationships can be stable when partners disperse freely and have the possibility of forming associations with many alternative genotypes. Theory predicts that high symbiont relatedness should resolve this problem, but the mechanisms to enforce this have rarely been...... studied. We show that African fungus-growing termites propagate single variants of their Termitomyces symbiont, despite initiating cultures from genetically variable spores from the habitat. High inoculation density in the substrate followed by fusion among clonally related mycelia enhances the efficiency...... of spore production in proportion to strain frequency. This positive reinforcement results in an exclusive lifetime association of each host colony with a single fungal symbiont and hinders the evolution of cheating. Our findings explain why vertical symbiont transmission in fungus-growing termites is rare...

  12. High-resolution genetic analysis of the requirements for horizontal transmission of the ESBL plasmid from Escherichia coli O104:H4.

    Science.gov (United States)

    Yamaichi, Yoshiharu; Chao, Michael C; Sasabe, Jumpei; Clark, Lars; Davis, Brigid M; Yamamoto, Nozomi; Mori, Hiroshi; Kurokawa, Ken; Waldor, Matthew K

    2015-01-01

    Horizontal dissemination of the genes encoding extended spectrum beta-lactamases (ESBLs) via conjugative plasmids is facilitating the increasingly widespread resistance of pathogens to beta-lactam antibiotics. However, there is relatively little known about the regulatory factors and mechanisms that govern the spread of these plasmids. Here, we carried out a high-throughput, transposon insertion site sequencing analysis (TnSeq) to identify genes that enable the maintenance and transmission of pESBL, an R64 (IncI1)-related resistance plasmid that was isolated from Escherichia coli O104:H4 linked to a recent large outbreak of gastroenteritis. With a few exceptions, the majority of the genes identified as required for maintenance and transmission of pESBL matched those of their previously defined R64 counterparts. However, our analyses of the high-density transposon insertion library in pESBL also revealed two very short and linked regions that constitute a previously unrecognized regulatory system controlling spread of IncI1 plasmids. In addition, we investigated the function of the pESBL-encoded M.EcoGIX methyltransferase, which is also encoded by many other IncI1 and IncF plasmids. This enzyme proved to protect pESBL from restriction in new hosts, suggesting it aids in expanding the plasmid's host range. Collectively, our work illustrates the power of the TnSeq approach to enable rapid and comprehensive analyses of plasmid genes and sequences that facilitate the dissemination of determinants of antibiotic resistance.

  13. Ongoing Horizontal and Vertical Transmission of Virulence Genes and papA Alleles among Escherichia coli Blood Isolates from Patients with Diverse-Source Bacteremia

    Science.gov (United States)

    Johnson, James R.; O'Bryan, Timothy T.; Kuskowski, Michael; Maslow, Joel N.

    2001-01-01

    The phylogenetic distributions of multiple putative virulence factors (VFs) and papA (P fimbrial structural subunit) alleles among 182 Escherichia coli blood isolates from patients with diverse-source bacteremia were defined. Phylogenetic correspondence among these strains, the E. coli Reference (ECOR) collection, and other collections of extraintestinal pathogenic E. coli (ExPEC) was assessed. Although among the 182 bacteremia isolates phylogenetic group B2 predominated, exhibited the greatest concentration of individual VFs, and contained the largest number of familiar virulent clones, other phylogenetic groups exhibited greater concentrations of certain VFs than did group B2 and included several additional virulent clones. Certain of the newly detected VF genes, e.g., fyuA (yersiniabactin; 76%) and focG (F1C fimbriae; 25%), were as prevalent or more prevalent than their more familiar traditional counterparts, e.g., iut (aerobactin; 57%) and sfaS (S fimbriae; 14%), thus possibly offering additional useful targets for preventive interventions. Considerable diversity of VF profiles was observed at every level within the phylogenetic tree, including even within individual lineages. This suggested that many different pathways can lead to extraintestinal virulence in E. coli and that the evolution of ExPEC, which involves extensive horizontal transmission of VFs and continuous remodeling of pathogenicity-associated islands, is a highly active, ongoing process. PMID:11500406

  14. Various infection status and molecular evidence for horizontal transmission and recombination of Wolbachia and Cardinium among rice planthoppers and related species

    Institute of Scientific and Technical Information of China (English)

    Kai-Jun Zhang; Xiao Han; Xiao-Yue Hong

    2013-01-01

    Wolbachia and Cardinium are widely distributed and are considered important for their ability to disturb reproduction and affect other fitness-related traits of their hosts.By using multilocus sequence typing (MLST),RFLP (restriction fragment length polymorphism) and 16S ribosomal DNA gene sequencing methods,we extensively surveyed Wolbachia and Cardinium infection status of four predominant rice planthoppers and one kind of leafhopper in different rice fields.The results demonstrated that Sogatella furcifera (Horváth) and Laodelphax striatellus (Fallén) were infected with the same Wolbachia strain (wStri),while Nilaparvata lugens (St(a)l) and its closely related species Nilaparvata muiri China were infected with two phylogeneticlly distant strains,wLug and wMui,respectively.Three new Wolbachia strains (provisionally named wMfasl,wMfas2 and wMfas3) were detected in the leafhopper Macrostelesfascifrons (St(a)l).Only S.furcifera was co-infected with Cardinium,which indicated that the distribution of Cardinium in these rice planthoppers was narrower than that of Wolbachia.Unambiguous intragenic recombination events among these Wolbachia strains and incongruent phylogenetic relationships show that the connections between different Wolbachia strains and hosts were more complex than we expected.These results suggest that horizontal transmission and host associated specialization are two factors affecting Wolbachia and Cardinium infections among planthoppers and their related species.

  15. An outbreak of feline infectious peritonitis in a Taiwanese shelter: epidemiologic and molecular evidence for horizontal transmission of a novel type II feline coronavirus.

    Science.gov (United States)

    Wang, Ying-Ting; Su, Bi-Ling; Hsieh, Li-En; Chueh, Ling-Ling

    2013-07-17

    Feline infectious peritonitis (FIP) is a fatal disease caused by feline coronavirus (FCoV) infection. FCoV can be divided into serotypes I and II. The virus that causes FIP (FIPV) is believed to occur sporadically and spread infrequently from cat to cat. Recently, an FIP outbreak from an animal shelter was confirmed in Taiwan. FCoV from all the cats in this shelter were analyzed to determine the epidemiology of this outbreak. Thirteen of 46 (28.2%) cats with typical signs of FIP were identified. Among them, seven cats were confirmed by necropsy and/or histopathological examinations. Despite the fact that more than one FCoV was identified in this multi-cat environment, the eight FIP cats were invariably found to be infected with a type II FCoV. Sequence analysis revealed that the type II FIPV detected from fecal samples, body effusions and granulomatous tissue homogenates from the cats that succumbed to FIP all harbored an identical recombination site in their S gene. Two of the cats that succumbed to FIP were found to harbor an identical nonsense mutation in the 3c gene. Fecal shedding of this type II virus in the effusive form of FIP can be detected up to six days before death. Taken together, our data demonstrate that horizontal transmission of FIPV is possible and that FIP cats can pose a potential risk to other cats living in the same environment.

  16. Horizontal transmission experiment of paratuberculosis

    NARCIS (Netherlands)

    Roermund, van H.J.W.; Jong, de M.C.M.

    2005-01-01

    In September 2001 two groups of 5 calves were placed between two groups of 6 infectious cows in a row during 3 months (Period 1). Calves were one week old at the start and born in MAP-unsuspected status-10 herds. Cows were artificially (orally) infected at one month of age in Januari 1999. Each calf

  17. Avaliação da prevenção da transmissão vertical do HIV em Belo Horizonte, MG, Brasil Evaluación de la prevención de la transmisión vertical del VIH en Belo Horizone, MG, Brasil Prevention evaluation of HIV vertical transmission in Belo Horizonte, MG, Brazil

    Directory of Open Access Journals (Sweden)

    Francisco Carlos Felix Lana

    2010-08-01

    Full Text Available A pesquisa teve como objetivo analisar o pré-natal ofertado na rede básica de saúde do Distrito Leste do município de Belo Horizonte e as ações direcionadas à prevenção da transmissão vertical do HIV. Foi discutida a permanência de taxas significativas de transmissão do HIV na vigência de tecnologias adequadas para a sua prevenção. Por meio de uma análise descritiva e univariada, que abordou os bancos de dados Sisprenatal e Sinan, identificou-se entraves que se relacionam diretamente a problemas observados na captação precoce de gestantes e na instituição da terapêutica em tempo adequado. O envolvimento dos gestores e a capacitação dos profissionais envolvidos é essencial para o correto direcionamento de ações que possibilitem a prevenção efetiva da transmissão vertical do HIV.Este trabajo de investigación tuve como objetivo analizar la atención prenatal de la red básica del Distrito Este del municipio de Belo Horizonte y las acciones que buscan prevenir la transmisión del VIH de madre a hijo. Se discutió el porqué de las altas tasas de transmisión vertical de dicho virus cuando hay tecnologías adecuadas para su prevención. Se realizó un análisis descriptivo y univariado de información de los bancos de datos Sisprenatal y Sinan. Se identificaron obstáculos para los problemas observados en la captación temprana de embarazadas y en la institución de la terapéutica en tiempo adecuado. El compromiso de los gestores y la capacitación de los profesionales son esenciales para orientar acciones de prevención efectiva de la transmisión vertical del VIH.The study had as objective to analyze the prenatal care services offered by the East District's primary healthcare network of the city of Belo Horizonte as well as actions for the prevention of vertical transmission of HIV. It discussed the still significant rates of transmission of HIV in the presence of appropriate technologies for its prevention. Barriers

  18. Diversity and localization of bacterial symbionts in three whitefly species (Hemiptera: Aleyrodidae) from the east coast of the Adriatic Sea.

    Science.gov (United States)

    Skaljac, M; Zanić, K; Hrnčić, S; Radonjić, S; Perović, T; Ghanim, M

    2013-02-01

    Several whitefly species (Hemiptera: Aleyrodidae) are cosmopolitan phloem-feeders that cause serious damage in numerous agricultural crops. All whitefly species harbor a primary bacterial symbiont and a diverse array of secondary symbionts which may influence several aspects of the insect's biology. We surveyed infections by secondary symbionts in Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood) and Siphoninus phillyreae (Haliday) from areas in the east cost of the Adriatic Sea. Both the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) B. tabaci genetic groups were detected in Montenegro, whereas only the MED was confirmed in Croatia. Trialeurodes vaporariorum and S. phillyreae were found in all areas surveyed. MEAM1 and MED exhibited similarity to previously reported infections, while populations of T. vaporariorum from Montenegro harbored Rickettsia, Wolbachia and Cardinium in addition to previously reported Hamiltonella and Arsenopnohus. Siphoninus phillyreae harbored Hamiltonella, Wolbachia, Cardinium and Arsenophonus, with the latter appearing in two alleles. Multiple infections of all symbionts were common in the three insect species tested, with some reaching near fixation. Florescent in situ hybridization showed new localization patterns for Hamiltonella in S. phillyreae, and the morphology of the bacteriosome differed from that observed in other whitefly species. Our results show new infections with bacterial symbionts in the whitefly species studied. Infections with the same symbionts in reproductively isolated whitefly species confirm complex relationships between whiteflies and bacterial symbionts, and suggest possible horizontal transfer of some of these bacteria.

  19. Fungal symbionts alter plant drought response.

    Science.gov (United States)

    Worchel, Elise R; Giauque, Hannah E; Kivlin, Stephanie N

    2013-04-01

    Grassland productivity is often primarily limited by water availability, and therefore, grasslands may be especially sensitive to climate change. Fungal symbionts can mediate plant drought response by enhancing drought tolerance and avoidance, but these effects have not been quantified across grass species. We performed a factorial meta-analysis of previously published studies to determine how arbuscular mycorrhizal (AM) fungi and endophytic fungal symbionts affect growth of grasses under drought. We then examined how the effect of fungal symbionts on plant growth was influenced by biotic (plant photosynthetic pathway) and abiotic (level of drought) factors. We also measured the phylogenetic signal of fungal symbionts on grass growth under control and drought conditions. Under drought conditions, grasses colonized by AM fungi grew larger than those without mycorrhizal symbionts. The increased growth of grasses conferred from fungal symbionts was greatest at the lowest soil moisture levels. Furthermore, under both drought and control conditions, C3 grasses colonized by AM fungi grew larger than C3 grasses without symbionts, but the biomass of C4 grasses was not affected by AM fungi. Endophytes did not increase plant biomass overall under any treatment. However, there was a phylogenetically conserved increase in plant biomass in grasses colonized by endophytes. Grasses and their fungal symbionts seem to interact within a context-dependent symbiosis, varying with biotic and abiotic conditions. Because plant-fungal symbioses significantly alter plant drought response, including these responses could improve our ability to predict grassland functioning under global change.

  20. Co-niche construction between hosts and symbionts: ideas and evidence.

    Science.gov (United States)

    Borges, Renee M

    2017-07-01

    Symbiosis is a process that can generate evolutionary novelties and can extend the phenotypic niche space of organisms. Symbionts can act together with their hosts to co-construct host organs, within which symbionts are housed. Once established within hosts, symbionts can also influence various aspects of host phenotype, such as resource acquisition, protection from predation by acquisition of toxicity, as well as behaviour. Once symbiosis is established, its fidelity between generations must be ensured. Hosts evolve various mechanisms to screen unwanted symbionts and to facilitate faithful transmission of mutualistic partners between generations. Microbes are the most important symbionts that have influenced plant and animal phenotypes; multicellular organisms engage in developmental symbioses with microbes at many stages in ontogeny. The co-construction of niches may result in composite organisms that are physically nested within each other. While it has been advocated that these composite organisms need new evolutionary theories and perspectives to describe their properties and evolutionary trajectories, it appears that standard evolutionary theories are adequate to explore selection pressures on their composite or individual traits. Recent advances in our understanding of composite organisms open up many important questions regarding the stability and transmission of these units.

  1. Co-niche construction between hosts and symbionts: ideas and evidence

    Indian Academy of Sciences (India)

    RENEE M. BORGES

    2017-07-01

    Symbiosis is a process that can generate evolutionary novelties and can extend the phenotypic niche space of organisms. Symbionts can act together with their hosts to co-construct host organs, within which symbionts are housed. Once established within hosts, symbionts can also influence various aspects of host phenotype, such as resource acquisition, protection from predation by acquisition of toxicity, as well as behaviour. Once symbiosis is established, its fidelity between generations must be ensured. Hosts evolve various mechanisms to screen unwanted symbionts and to facilitate faithful transmission of mutualistic partnersbetween generations. Microbes are the most important symbionts that have influenced plant and animal phenotypes; multicellular organisms engage in developmental symbioses with microbes at many stages in ontogeny. The co-construction of niches may result in composite organisms that are physically nested within each other. While it has been advocated that these composite organisms need new evolutionary theories and perspectives to describe their properties and evolutionary trajectories, it appears that standard evolutionary theories are adequate to explore selection pressures on their composite or individual traits. Recent advances in our understanding of composite organisms open up many important questions regarding the stability and transmission of these units.

  2. Cyanobacterial diversity and a new acaryochloris-like symbiont from Bahamian sea-squirts.

    Directory of Open Access Journals (Sweden)

    Susanna López-Legentil

    Full Text Available Symbiotic interactions between ascidians (sea-squirts and microbes are poorly understood. Here we characterized the cyanobacteria in the tissues of 8 distinct didemnid taxa from shallow-water marine habitats in the Bahamas Islands by sequencing a fragment of the cyanobacterial 16S rRNA gene and the entire 16S-23S rRNA internal transcribed spacer region (ITS and by examining symbiont morphology with transmission electron (TEM and confocal microscopy (CM. As described previously for other species, Trididemnum spp. mostly contained symbionts associated with the Prochloron-Synechocystis group. However, sequence analysis of the symbionts in Lissoclinum revealed two unique clades. The first contained a novel cyanobacterial clade, while the second clade was closely associated with Acaryochloris marina. CM revealed the presence of chlorophyll d (chl d and phycobiliproteins (PBPs within these symbiont cells, as is characteristic of Acaryochloris species. The presence of symbionts was also observed by TEM inside the tunic of both the adult and larvae of L. fragile, indicating vertical transmission to progeny. Based on molecular phylogenetic and microscopic analyses, Candidatus Acaryochloris bahamiensis nov. sp. is proposed for this symbiotic cyanobacterium. Our results support the hypothesis that photosymbiont communities in ascidians are structured by host phylogeny, but in some cases, also by sampling location.

  3. Cardinium symbionts induce haploid thelytoky in most clones of three closely related Brevipalpus species

    NARCIS (Netherlands)

    T.V.M. Groot; J.A.J. Breeuwer

    2006-01-01

    Bacterial symbionts that manipulate the reproduction of their host to increase their own transmission are widespread. Most of these bacteria are Wolbachia, but recently a new bacterium, named Cardinium, was discovered that is capable of the same manipulations. In the host species Brevipalpus phoenic

  4. Co-infection and localization of secondary symbionts in two whitefly species

    Science.gov (United States)

    2010-01-01

    and different secondary symbionts is maintained through vertical transmission via the egg, and is unique to whiteflies. This system provides opportunities to study interactions among symbionts that co-inhabit the same cell in the same host: these can be cooperative or antagonistic, may affect the symbiotic contents over time, and may also affect the host by competing with the primary symbiont for space and resources. PMID:20462452

  5. Co-infection and localization of secondary symbionts in two whitefly species

    Directory of Open Access Journals (Sweden)

    Kontsedalov Svetlana

    2010-05-01

    bacteriocyte by the primary and different secondary symbionts is maintained through vertical transmission via the egg, and is unique to whiteflies. This system provides opportunities to study interactions among symbionts that co-inhabit the same cell in the same host: these can be cooperative or antagonistic, may affect the symbiotic contents over time, and may also affect the host by competing with the primary symbiont for space and resources.

  6. Horizontal Accelerator

    Data.gov (United States)

    Federal Laboratory Consortium — The Horizontal Accelerator (HA) Facility is a versatile research tool available for use on projects requiring simulation of the crash environment. The HA Facility is...

  7. Culture and manipulation of insect facultative symbionts.

    Science.gov (United States)

    Pontes, Mauricio H; Dale, Colin

    2006-09-01

    Insects from many different taxonomic groups harbor maternally transmitted bacterial symbionts. Some of these associations are ancient in origin and obligate in nature whereas others originated more recently and are facultative. Previous research focused on the biology of ancient obligate symbionts with essential nutritional roles in their insect hosts. However, recent important advances in understanding the biology of facultative associations have been driven by the development of techniques for the culture, genetic modification and manipulation of facultative symbionts. In this review, we examine these available experimental techniques and illustrate how they have provided fascinating new insight into the nature of associations involving facultative symbionts. We also propose a rationale for future research based on the integration of genomics and experimentation.

  8. Characteristics, phenotype, and transmission of Wolbachia in the sweet potato whitefly, Bemisia tabaci (Hemiptera: Aleyrodidae), and its parasitoid Eretmocerus sp. nr. emiratus (Hymenoptera: Aphelinidae).

    Science.gov (United States)

    Chiel, Elad; Kelly, Suzanne E; Harris, Alexandre M; Gebiola, Marco; Li, Xianchun; Zchori-Fein, Einat; Hunter, Martha S

    2014-04-01

    Wolbachia is a common intracellular bacterial endosymbiont of insects, causing a variety of effects including reproductive manipulations such as cytoplasmic incompatibility (CI). In this study, we characterized Wolbachia in the whitefly Bemisia tabaci and in the whitefly parasitoid Eretmocerus sp. nr. emiratus. We also tested for horizontal transmission of Wolbachia between and within trophic levels, and we determined the phenotype of Wolbachia in E. sp. nr. emiratus. Using multilocus sequence typing and phylogenetic analyses, we found that B. tabaci and E. sp. nr. emiratus each harbor a different and unique strain of Wolbachia. Both strains belong to the phylogenetic supergroup B. No evidence for horizontal transmission of Wolbachia between and within trophic levels was found in our study system. Finally, crossing results were consistent with a CI phenotype; when Wolbachia-infected E. sp. nr. emiratus males mate with uninfected females, wasp progeny survival dropped significantly, and the number of females was halved. This is the first description of CI caused by Wolbachia in the economically important genus Eretmocerus. Our study underscores the expectation that horizontal transmission events occur rarely in the dynamics of secondary symbionts such as Wolbachia, and highlights the importance of understanding the effects of symbionts on the biology of natural enemies.

  9. Transcriptomic immune response of the cotton stainer Dysdercus fasciatus to experimental elimination of vitamin-supplementing intestinal symbionts.

    Directory of Open Access Journals (Sweden)

    Eugen Bauer

    Full Text Available The acquisition and vertical transmission of bacterial symbionts plays an important role in insect evolution and ecology. However, the molecular mechanisms underlying the stable maintenance and control of mutualistic bacteria remain poorly understood. The cotton stainer Dysdercus fasciatus harbours the actinobacterial symbionts Coriobacterium glomerans and Gordonibacter sp. in its midgut. The symbionts supplement limiting B vitamins and thereby significantly contribute to the host's fitness. In this study, we experimentally disrupted the symbionts' vertical transmission route and performed comparative transcriptomic analyses of genes expressed in the gut of aposymbiotic (symbiont-free and control individuals to study the host immune response in presence and absence of the mutualists. Annotation of assembled cDNA reads identified a considerable number of genes involved in the innate immune system, including different protein isoforms of several immune effector proteins (specifically i-type lysozyme, defensin, hemiptericin, and pyrrhocoricin, suggesting the possibility for a highly differentiated response towards the complex resident microbial community. Gene expression analyses revealed a constitutive expression of transcripts involved in signal transduction of the main insect immune pathways, but differential expression of certain antimicrobial peptide genes. Specifically, qPCRs confirmed the significant down-regulation of c-type lysozyme and up-regulation of hemiptericin in aposymbiotic individuals. The high expression of c-type lysozyme in symbiont-containing bugs may serve to lyse symbiont cells and thereby harvest B-vitamins that are necessary for subsistence on the deficient diet of Malvales seeds. Our findings suggest a sophisticated host response to perturbation of the symbiotic gut microbiota, indicating that the innate immune system not only plays an important role in combating pathogens, but also serves as a communication interface

  10. Acute schistosomiasis outbreak in the metropolitan area of Belo Horizonte, Minas Gerais: alert about the risk of unnoticed transmission increased by growing rural tourism

    OpenAIRE

    Enk,Martin J; Amanda Amorim; Schall,Virginia T.

    2003-01-01

    The present article describes the occurrence of 17 cases of acute schistosomiasis in the metropolitan area of Belo Horizonte, state of Minas Gerais, Brazil. All individuals affected took a bath in a swimming pool of a holiday resort that was provided with water from a nearby brook. The apparently clean water and the absence of snails in the pool gave the wrong impression that there was no risk for infection. During a malacological survey at the site snails of the species Biomphalaria glabrata...

  11. What can symbiont titres tell us about co-evolution of Wolbachia and their host?

    Science.gov (United States)

    Correa, C Carolina; Ballard, J William O

    2014-05-01

    There is a long-standing prediction that associations with vertically transmitted symbionts evolve towards maximisation of host reproductive success, eventually leading to mutualist symbiosis and coadaptation. Under this scenario, the regulation of symbiont titres in host tissues would be expected to be greater when partners have coevolved for a long time than when they have recently met. Wolbachia pipientis, a common vertically transmitted symbiont of invertebrates, often has the capacity to spread through the host population without being beneficial to the hosts, by means of reducing the hatch rate in crosses between uninfected females and infected males. This manipulation, namely cytoplasmic incompatibility (CI), may exert strong selection on the accuracy of infection transmission from mother to offspring, and therefore, on regulation of symbiont titres in the ova. Here, we examined the symbiont density dynamics in gonads of Drosophila simulans infected with the wMa strain of Wolbachia, known to cause mild CI and likely to be the oldest Wolbachia infection known to this fly species. Further, we compared these results with those obtained for the more recent association between D. simulans and the potent CI-inducer wHa (Correa and Ballard, 2012). We aimed to determine if the regulation of Wolbachia density in fly gonads is greater in the older association, as would be predicted solely by gradual coadaptation, or if the selection exerted by CI on reproductive fitness could also play a role, therefore showing tighter regulation on flies with the stronger CI-inducing strain. We observed that Wolbachia density in gonads of wMa infected flies changed with laboratory adaptation and were disturbed by environmental challenges, which contrasted with the stability of ovarian wHa density to the same treatments. Our observations are in line with the prediction that selection on reproductive fitness influences the evolution symbiont density regulation in Drosophila, and may

  12. Social insect symbionts: evolution in homeostatic fortresses

    DEFF Research Database (Denmark)

    Hughes, David P; Pierce, Naomi E; Boomsma, Jacobus J

    2008-01-01

    The massive environmentally buffered nests of some social insects can contain millions of individuals and a wide variety of parasites, commensals and mutualists. We suggest that the ways in which these homeostatic fortress environments affect the evolution of social insect symbionts are relevant...... for epidemiology, evolutionary biology and macroecology. We contend that specialized parasites will tend to become less virulent and mutualists less cooperative, compared to those associated with solitary or small-colony hosts. These processes are expected to contribute to the very high symbiont diversity observed...

  13. Acute schistosomiasis outbreak in the metropolitan area of Belo Horizonte, Minas Gerais: alert about the risk of unnoticed transmission increased by growing rural tourism.

    Science.gov (United States)

    Enk, Martin J; Amorim, Amanda; Schall, Virginia T

    2003-09-01

    The present article describes the occurrence of 17 cases of acute schistosomiasis in the metropolitan area of Belo Horizonte, state of Minas Gerais, Brazil. All individuals affected took a bath in a swimming pool of a holiday resort that was provided with water from a nearby brook. The apparently clean water and the absence of snails in the pool gave the wrong impression that there was no risk for infection. During a malacological survey at the site snails of the species Biomphalaria glabrata were found and tested positive for Schistosoma mansoni. All the patients live in the middle-class area of Barreiro, metropolitan area of Belo Horizonte and have medium grade school education. The difficulties in establishing the right diagnosis is expressed by the search for medical attention in 17 different medical facilities, the wide range of laboratory test and the inadequate treatment administration. A lack of knowledge about the disease was found in all groups studied. The booming rural tourism in endemic areas is identified as a probable risk factor for infection, especially for individuals of the non-immune middle and upper class parts of the society in urban centers. Special attention is given to a multidisciplinary approach to the complex issue of disease control and prevention.

  14. Acute schistosomiasis outbreak in the metropolitan area of Belo Horizonte, Minas Gerais: alert about the risk of unnoticed transmission increased by growing rural tourism

    Directory of Open Access Journals (Sweden)

    Martin J Enk

    2003-09-01

    Full Text Available The present article describes the occurrence of 17 cases of acute schistosomiasis in the metropolitan area of Belo Horizonte, state of Minas Gerais, Brazil. All individuals affected took a bath in a swimming pool of a holiday resort that was provided with water from a nearby brook. The apparently clean water and the absence of snails in the pool gave the wrong impression that there was no risk for infection. During a malacological survey at the site snails of the species Biomphalaria glabrata were found and tested positive for Schistosoma mansoni. All the patients live in the middle-class area of Barreiro, metropolitan area of Belo Horizonte and have medium grade school education. The difficulties in establishing the right diagnosis is expressed by the search for medical attention in 17 different medical facilities, the wide range of laboratory test and the inadequate treatment administration. A lack of knowledge about the disease was found in all groups studied. The booming rural tourism in endemic areas is identified as a probable risk factor for infection, especially for individuals of the non-immune middle and upper class parts of the society in urban centers. Special attention is given to a multidisciplinary approach to the complex issue of disease control and prevention.

  15. Potential applications of insect symbionts in biotechnology.

    Science.gov (United States)

    Berasategui, Aileen; Shukla, Shantanu; Salem, Hassan; Kaltenpoth, Martin

    2016-02-01

    Symbiotic interactions between insects and microorganisms are widespread in nature and are often the source of ecological innovations. In addition to supplementing their host with essential nutrients, microbial symbionts can produce enzymes that help degrade their food source as well as small molecules that defend against pathogens, parasites, and predators. As such, the study of insect ecology and symbiosis represents an important source of chemical compounds and enzymes with potential biotechnological value. In addition, the knowledge on insect symbiosis can provide novel avenues for the control of agricultural pest insects and vectors of human diseases, through targeted manipulation of the symbionts or the host-symbiont associations. Here, we discuss different insect-microbe interactions that can be exploited for insect pest and human disease control, as well as in human medicine and industrial processes. Our aim is to raise awareness that insect symbionts can be interesting sources of biotechnological applications and that knowledge on insect ecology can guide targeted efforts to discover microorganisms of applied value.

  16. Characterization of a newly discovered symbiont of the whitefly Bemisia tabaci (Hemiptera: Aleyrodidae).

    Science.gov (United States)

    Bing, Xiao-Li; Yang, Jiao; Zchori-Fein, Einat; Wang, Xiao-Wei; Liu, Shu-Sheng

    2013-01-01

    Bemisia tabaci (Hemiptera: Aleyrodidae) is a species complex containing >28 cryptic species, some of which are important crop pests worldwide. Like many other sap-sucking insects, whiteflies harbor an obligatory symbiont, "Candidatus Portiera aleyrodidarum," and a number of secondary symbionts. So far, six genera of secondary symbionts have been identified in B. tabaci. In this study, we report and describe the finding of an additional bacterium in the indigenous B. tabaci cryptic species China 1 (formerly known as B. tabaci biotype ZHJ3). Phylogenetic analysis based on the 16S rRNA and gltA genes showed that the bacterium belongs to the Alphaproteobacteria subdivision of the Proteobacteria and has a close relationship with human pathogens of the genus Orientia. Consequently, we temporarily named it Orientia-like organism (OLO). OLO was found in six of eight wild populations of B. tabaci China 1, with the infection rate ranging from 46.2% to 76.8%. Fluorescence in situ hybridization (FISH) of B. tabaci China 1 in nymphs and adults revealed that OLOs are confined to the bacteriome and co-occur with "Ca. Portiera aleyrodidarum." The vertical transmission of OLO was demonstrated by detection of OLO at the anterior pole end of the oocytes through FISH. Quantitative PCR analysis of population dynamics suggested a complex interaction between "Ca. Portiera aleyrodidarum" and OLO. Based on these results, we propose "Candidatus Hemipteriphilus asiaticus" for the classification of this symbiont from B. tabaci.

  17. Horizontal transmission of malignancy: in-vivo fusion of human lymphomas with hamster stroma produces tumors retaining human genes and lymphoid pathology.

    Directory of Open Access Journals (Sweden)

    David M Goldenberg

    Full Text Available We report the in-vivo fusion of two Hodgkin lymphomas with golden hamster cheek pouch cells, resulting in serially-transplanted (over 5-6 years GW-532 and GW-584 heterosynkaryon tumor cells displaying both human and hamster DNA (by FISH, lymphoma-like morphology, aggressive metastasis, and retention of 7 human genes (CD74, CXCR4, CD19, CD20, CD71, CD79b, and VIM out of 24 tested by PCR. The prevalence of B-cell restricted genes (CD19, CD20, and CD79b suggests that this uniform population may be the clonal initiating (malignant cells of Hodgkin lymphoma, despite their not showing translation to their respective proteins by immunohistochemical analysis. This is believed to be the first report of in-vivo cell-cell fusion of human lymphoma and rodent host cells, and may be a method to disclose genes regulating both organoid and metastasis signatures, suggesting that the horizontal transfer of tumor DNA to adjacent stromal cells may be implicated in tumor heterogeneity and progression. The B-cell gene signature of the hybrid xenografts suggests that Hodgkin lymphoma, or its initiating cells, is a B-cell malignancy.

  18. Evidence of two lineages of the symbiont 'Candidatus Erwinia dacicola' in Italian populations of Bactrocera oleae (Rossi) based on 16S rRNA gene sequences.

    Science.gov (United States)

    Savio, Claudia; Mazzon, Luca; Martinez-Sañudo, Isabel; Simonato, Mauro; Squartini, Andrea; Girolami, Vincenzo

    2012-01-01

    The close association between the olive fly Bactrocera oleae (Rossi) (Diptera: Tephritidae) and bacteria has been known for more than a century. Recently, the presence of a host-specific, hereditary, unculturable symbiotic bacterium, designated 'Candidatus Erwinia dacicola', has been described inside the cephalic organ of the fly, called the oesophageal bulb. In the present study, the 16S rRNA gene sequence variability of 'Ca. E. dacicola' was examined within and between 26 Italian olive fly populations sampled across areas where olive trees occur in the wild and areas where cultivated olive trees have been introduced through history. The bacterial contents of the oesophageal bulbs of 314 olive flies were analysed and a minimum of 781 bp of the 16S rRNA gene was sequenced. The corresponding host fly genotype was assessed by sequencing a 776 bp portion of the mitochondrial genome. Two 'Ca. E. dacicola' haplotypes were found (htA and htB), one being slightly more prevalent than the other (57%). The two haplotypes did not co-exist in the same individuals, as confirmed by cloning. Interestingly, the olive fly populations of the two main Italian islands, Sicily and Sardinia, appeared to be represented exclusively by the htB and htA haplotypes, respectively, while peninsular populations showed both bacterial haplotypes in different proportions. No significant correlation emerged between the two symbiont haplotypes and the 16 host fly haplotypes observed, suggesting evidence for a mixed model of vertical and horizontal transmission of the symbiont during the fly life cycle.

  19. Symbiont Polyphyly, Co-Evolution, and Necessity in Pentatomid Stinkbugs from Costa Rica

    Directory of Open Access Journals (Sweden)

    Kalia S.I. Bistolas

    2014-07-01

    Full Text Available Interdomain symbioses with bacteria allow insects to take advantage of underutilized niches and provide the foundation for their evolutionary success in neotropical ecosystems. The gut microbiota of 13 micro-allopatric tropical pentatomid species, from a Costa Rican lowland rainforest, was characterized and compared with insect and host plant phylogenies. Like other families within the Pentatomomorpha, these insects (within seven genera - Antiteuchus, Arvelius, Edessa, Euschistus, Loxa, Mormidea and Sibaria house near-monocultures of gamma-proteobacteria in modified midgut crypts, comprising three distinct lineages within the family Enterobacteriaceae. Identity of the dominant bacteria (78-100% of the recovered 16S rRNA genes was partially congruent with insect phylogeny, at the level of subfamily and tribe, with bacteria closely related to Erwinia observed in six species of the subfamily Pentatominae, and bacteria bacteria in a novel clade of Enterobacteriaceae for seven species within the subfamilies Edessinae and Discocephalinae. Symbiont replacement (i.e. bacterial ‘contamination’ from the environment is probable due to modified maternal transmission by smearing of bacteria onto the egg surfaces during oviposition. This strategy was confirmed for Sibaria englemani, and suspected for four species from two subfamilies, based on observed probing of eggs by nymphs in captivity. Symbiont-deprived S. englemani, acquired via egg surface sterilization, exhibited significantly extended second stadia (9.1 days compared with 7.9 days for symbiotic nymphs; p=0.0001, Wilcoxon’s rank with Bonferroni correction, slower linearized growth rates (p=0.005, Welch 2-sample t-test, and observable differences in ceca morphology compared to symbiotic nymphs. Combined, these results suggest a role of the symbiont in host development, the reliable transference of symbionts via egg surfaces, and a degree of co-speciation between symbiont and tropical pentatomid

  20. Earthworm symbiont Verminephrobacter eiseniae mediates natural transformation within the host egg capsules using type IV pili

    Directory of Open Access Journals (Sweden)

    SEANA Kelyn DAVIDSON

    2014-10-01

    Full Text Available The dense microbial communities commonly associated with plants and animals should offer many opportunities for horizontal gene transfer (HGT through described mechanisms of DNA exchange including natural transformation. However, studies of the significance of natural transformation have focused primarily on pathogens. The study presented here demonstrates highly efficient DNA exchange by natural transformation in a common symbiont of earthworms. The obligate bacterial symbiont Verminephrobacter eiseniae is a member of a microbial consortium of the earthworm Eisenia fetida that is transmitted into the egg capsules to colonize the embryonic worms. In the study presented here, by testing for transformants under different conditions in culture, we demonstrate that V. eiseniae can incorporate free DNA from the environment, that competency is regulated by environmental factors, and that it is sequence specific. Mutations in the type IV pili of V. eiseniae resulted in loss of DNA uptake, implicating the type IV pilus (TFP apparatus in DNA uptake. Furthermore, injection of DNA carrying antibiotic-resistance genes into egg capsules resulted in transformants within the capsule, demonstrating the relevance of DNA uptake within the earthworm system. The ability to take up species-specific DNA from the environment may explain the maintenance of the relatively large, intact genome of this long-associated obligate symbiont, and provides a mechanism for acquisition of foreign genes within the earthworm system.

  1. The Calyptogena magnifica chemoautotrophic symbiont genome

    Energy Technology Data Exchange (ETDEWEB)

    Newton, I.L.; Woyke, T.; Auchtung, T.A.; Dilly, G.F.; Dutton,R.J.; Fisher, M.C.; Fontanez, K.M.; Lau, E.; Stewart, F.J.; Richardson,P.M.; Barry, K.W.; Saunders, E.; Detter, J.C.; Wu, D.; Eisen, J.A.; Cavanaugh, C.M.

    2007-03-01

    Chemoautotrophic endosymbionts are the metabolic cornerstone of hydrothermal vent communities, providing invertebrate hosts with nearly all of their nutrition. The Calyptogena magnifica (Bivalvia: Vesicomyidae) symbiont, Candidatus Ruthia magnifica, is the first intracellular sulfur-oxidizing endosymbiont to have its genome sequenced, revealing a suite of metabolic capabilities. The genome encodes major chemoautotrophic pathways as well as pathways for biosynthesis of vitamins, cofactors, and all 20 amino acids required by the clam.

  2. Accumulation of radionuclides by lichen symbionts

    Energy Technology Data Exchange (ETDEWEB)

    Nifontova, M.G.; Kulikov, N.V. (AN SSSR, Sverdlovsk. Inst. Ehkologii Rastenij i Zhivotnykh)

    1983-01-01

    The aim of investigation is the quantitative estimation of ability and role of separate symbionts in the accumulation of radionuclides. As investigation volumes, durably cultivated green lichen alga Trebouxia erici and lichen fungi extracted from Cladonia rangiferina, Parmelia caperata and Acarospora fuscata are used. The accumulation of radioactive isotopes with fungi and seaweeds is estimated according to accumulation coefficients (AC) which are the ratio of radiation concentration in plants and agarized medium. Radionuclide content (/sup 90/Sr and /sup 137/Cs) is determined radiometrically. A special series of experiments is done to investigate radionuclide accumulation dependences with lichen seaweed and fungi on light conditions. It is shown that both symbionts of lichen-seaweed and fungus take part in the accumulation of radionuclide from outer medium (atmospheric fall-out and soil). However fungus component constituting the base of structural organization of thallus provides the greater part of radionuclides accumulated by the plant. Along with this the violation of viability of seaweed symbionts particularly in the case of light deficiency brings about the reduction of /sup 137/Cs sorption by seaweeds and tells on the total content of radiocesium in plant thallus.

  3. Interactions among symbionts operate across scales to influence parasite epidemics.

    Science.gov (United States)

    Halliday, Fletcher W; Umbanhowar, James; Mitchell, Charles E

    2017-10-01

    Parasite epidemics may be influenced by interactions among symbionts, which can depend on past events at multiple spatial scales. Within host individuals, interactions can depend on the sequence in which symbionts infect a host, generating priority effects. Across host individuals, interactions can depend on parasite phenology. To test the roles of parasite interactions and phenology in epidemics, we embedded multiple cohorts of sentinel plants, grown from seeds with and without a vertically transmitted symbiont, into a wild host population, and tracked foliar infections caused by three common fungal parasites. Within hosts, parasite growth was influenced by coinfections, but coinfections were often prevented by priority effects among symbionts. Across hosts, parasite phenology altered host susceptibility to secondary infections, symbiont interactions and ultimately the magnitude of parasite epidemics. Together, these results indicate that parasite phenology can influence parasite epidemics by altering the sequence of infection and interactions among symbionts within host individuals. © 2017 John Wiley & Sons Ltd/CNRS.

  4. Modulation of host immunity and reproduction by horizontally acquired Wolbachia.

    Science.gov (United States)

    Pigeault, Romain; Braquart-Varnier, Christine; Marcadé, Isabelle; Mappa, Gaëtan; Mottin, Elmina; Sicard, Mathieu

    2014-11-01

    The Wolbachia are symbiotic bacteria vertically transmitted from one host generation to another. However, a growing amount of data shows that horizontal transfers of Wolbachia also frequently occur within and between host species. The consequences of the arrival of new symbionts on host physiology can be studied by their experimental introduction in asymbiotic hosts. After experimental transfers of the eight major isopod Wolbachia strains in the isopod Porcellio dilatatus only two of them (wCon and wDil) were found to (1) have no pathogenic effect on the host and (2) be able to pass vertically to the host offspring. In the present work, we studied the influence of these two strains, able to complete an horizontal transfer, on immunity and reproduction of P. dilatatus at two stages of the transfer: (1) in recipient hosts that encounter the symbionts: to test the influence of symbiont when acquired during host life and (2) in vertically infected offspring: to test the influence of a symbiotic interaction occurring all lifelong. The impact of Wolbachia varied depending on the stage: there were clearer effects in vertically infected individuals than in those that acquired the symbionts during their lives. Moreover, the two Wolbachia strains showed contrasted effects: the strain wCon tended to reduce the reproductive investment but to maintain or increase immune parameters whilst wDil had positive effects on reproductive investment but decreased the investment in some immune parameters. These results suggest that horizontally acquisition of Wolbachia can influence the balance between host immune and reproductive traits.

  5. Standard methods for research on apis mellifera gut symbionts

    Science.gov (United States)

    Gut microbes can play an important role in digestion, disease resistance, and the general health of animals, but little is known about the biology of gut symbionts in Apis mellifera. This paper is part of a series on honey bee research methods, providing protocols for studying gut symbionts. We desc...

  6. Comparative genomics of vesicomyid clam (Bivalvia: Mollusca chemosynthetic symbionts

    Directory of Open Access Journals (Sweden)

    Girguis Peter R

    2008-12-01

    Full Text Available Abstract Background The Vesicomyidae (Bivalvia: Mollusca are a family of clams that form symbioses with chemosynthetic gamma-proteobacteria. They exist in environments such as hydrothermal vents and cold seeps and have a reduced gut and feeding groove, indicating a large dependence on their endosymbionts for nutrition. Recently, two vesicomyid symbiont genomes were sequenced, illuminating the possible nutritional contributions of the symbiont to the host and making genome-wide evolutionary analyses possible. Results To examine the genomic evolution of the vesicomyid symbionts, a comparative genomics framework, including the existing genomic data combined with heterologous microarray hybridization results, was used to analyze conserved gene content in four vesicomyid symbiont genomes. These four symbionts were chosen to include a broad phylogenetic sampling of the vesicomyid symbionts and represent distinct chemosynthetic environments: cold seeps and hydrothermal vents. Conclusion The results of this comparative genomics analysis emphasize the importance of the symbionts' chemoautotrophic metabolism within their hosts. The fact that these symbionts appear to be metabolically capable autotrophs underscores the extent to which the host depends on them for nutrition and reveals the key to invertebrate colonization of these challenging environments.

  7. Exploring the Symbiodinium rare biosphere provides evidence for symbiont switching in reef-building corals.

    Science.gov (United States)

    Boulotte, Nadine M; Dalton, Steven J; Carroll, Andrew G; Harrison, Peter L; Putnam, Hollie M; Peplow, Lesa M; van Oppen, Madeleine Jh

    2016-11-01

    Reef-building corals possess a range of acclimatisation and adaptation mechanisms to respond to seawater temperature increases. In some corals, thermal tolerance increases through community composition changes of their dinoflagellate endosymbionts (Symbiodinium spp.), but this mechanism is believed to be limited to the Symbiodinium types already present in the coral tissue acquired during early life stages. Compelling evidence for symbiont switching, that is, the acquisition of novel Symbiodinium types from the environment, by adult coral colonies, is currently lacking. Using deep sequencing analysis of Symbiodinium rDNA internal transcribed spacer 2 (ITS2) PCR amplicons from two pocilloporid coral species, we show evidence consistent with de novo acquisition of Symbiodinium types from the environment by adult corals following two consecutive bleaching events. Most of these newly detected symbionts remained in the rare biosphere (background types occurring below 1% relative abundance), but one novel type reached a relative abundance of ~33%. Two de novo acquired Symbiodinium types belong to the thermally resistant clade D, suggesting that this switching may have been driven by consecutive thermal bleaching events. Our results are particularly important given the maternal mode of Symbiodinium transmission in the study species, which generally results in high symbiont specificity. These findings will cause a paradigm shift in our understanding of coral-Symbiodinium symbiosis flexibility and mechanisms of environmental acclimatisation in corals.

  8. Habitat Visualization and Genomic Analysis of “Candidatus Pantoea carbekii,” the Primary Symbiont of the Brown Marmorated Stink Bug

    Science.gov (United States)

    Kenyon, Laura J.; Meulia, Tea; Sabree, Zakee L.

    2015-01-01

    Phytophagous pentatomid insects can negatively impact agricultural productivity and the brown marmorated stink bug (Halyomorpha halys) is an emerging invasive pest responsible for damage to many fruit crops and ornamental plants in North America. Many phytophagous stink bugs, including H. halys, harbor gammaproteobacterial symbionts that likely contribute to host development, and characterization of symbiont transmission/acquisition and their contribution to host fitness may offer alternative strategies for managing pest species. “Candidatus Pantoea carbekii” is the primary occupant of gastric ceca lumina flanking the distal midgut of H. halys insects and it is acquired each generation when nymphs feed on maternal extrachorion secretions following hatching. Insects prevented from symbiont uptake exhibit developmental delays and aberrant behaviors. To infer contributions of Ca. P. carbekii to H. halys, the complete genome was sequenced and annotated from a North American H. halys population. Overall, the Ca. P. carbekii genome is nearly one-fourth (1.2 Mb) that of free-living congenerics, and retains genes encoding many functions that are potentially host-supportive. Gene content reflects patterns of gene loss/retention typical of intracellular mutualists of plant-feeding insects. Electron and fluorescence in situ microscopic imaging of H. halys egg surfaces revealed that maternal extrachorion secretions were populated with Ca. P. carbekii cells. The reported findings detail a transgenerational mode of symbiont transmission distinct from that observed for intracellular insect mutualists and illustrate the potential additive functions contributed by the bacterial symbiont to this important agricultural pest. PMID:25587021

  9. Habitat visualization and genomic analysis of "Candidatus Pantoea carbekii," the primary symbiont of the brown marmorated stink bug.

    Science.gov (United States)

    Kenyon, Laura J; Meulia, Tea; Sabree, Zakee L

    2015-01-12

    Phytophagous pentatomid insects can negatively impact agricultural productivity and the brown marmorated stink bug (Halyomorpha halys) is an emerging invasive pest responsible for damage to many fruit crops and ornamental plants in North America. Many phytophagous stink bugs, including H. halys, harbor gammaproteobacterial symbionts that likely contribute to host development, and characterization of symbiont transmission/acquisition and their contribution to host fitness may offer alternative strategies for managing pest species. "Candidatus Pantoea carbekii" is the primary occupant of gastric ceca lumina flanking the distal midgut of H. halys insects and it is acquired each generation when nymphs feed on maternal extrachorion secretions following hatching. Insects prevented from symbiont uptake exhibit developmental delays and aberrant behaviors. To infer contributions of Ca. P. carbekii to H. halys, the complete genome was sequenced and annotated from a North American H. halys population. Overall, the Ca. P. carbekii genome is nearly one-fourth (1.2 Mb) that of free-living congenerics, and retains genes encoding many functions that are potentially host-supportive. Gene content reflects patterns of gene loss/retention typical of intracellular mutualists of plant-feeding insects. Electron and fluorescence in situ microscopic imaging of H. halys egg surfaces revealed that maternal extrachorion secretions were populated with Ca. P. carbekii cells. The reported findings detail a transgenerational mode of symbiont transmission distinct from that observed for intracellular insect mutualists and illustrate the potential additive functions contributed by the bacterial symbiont to this important agricultural pest. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  10. 高龋学龄前儿童变形链球菌的水平传播方式%Horizontal transmission of Streptococcus mutans in caries-active preschool children

    Institute of Scientific and Technical Information of China (English)

    胡丹阳; 崔伟; 罗燕萍; 杨继勇; 邓斌; 徐娟; 储冰峰; 王成龙

    2014-01-01

    Objective To analyze horizontal transmission patterns of Streptococcus mutans among caries-active preschool children for early interventions of dental caries. Methods Plaque samples obtained from 20 caries-active preschool children between 4 and 5 years of age were cultured under anaerobic conditions for isolating S. mutans, which were identified by morphological and biochemical analyses and PCR using primers homologous to the surface protein glucosyltransferase B (gtfB). The genotypes of the isolated S. mutans strains were determined by arbitrarily primed PCR (AP-PCR). Results Of the 200 S. mutans isolates obtained, 19 were excluded by biochemical analysis, and the remaining 181 isolates were identified as S. mutans by PCR with primers of gtfB, showing 37 different genotypes as identified by AP-PCR. Six children were found to carry S. mutans of a single genotype, 11 carried 2 genotypes, 2 had 3 genotypes, and 1 had 4 genotypes;2 children from different classes were found to carry S. mutans of the same single genotype. Conclusion We identified 37 genotypes of S. mutans in these caries-active preschool children, among whom horizontal transmissions of the strains were not found.%目的:研究高龋学龄前儿童变形链球菌的水平传播方式,为儿童龋病早期预防提供依据。方法收集20名4~5岁高龋学龄前儿童口腔中牙菌斑标本进行厌氧培养,通过细菌形态学观察、生物化学鉴定、聚合酶链反应(PCR)扩增变形链球菌基因的特异性片段葡糖基转移酶B(gtfB)以及随机引物聚合酶链反应(AP-PCR)等方法对获得的变形链球菌临床分离株进行鉴定。结果从20例高龋学龄前儿童口腔中分离获得200株变形链球菌临床分离株,经生物化学鉴定排除其中19株,获得181株变形链球菌临床分离株,变形链球菌的特异性基因gtfB的PCR扩增181株变形链球菌临床分离株均鉴定为变形链球菌,AP-PCR发现37

  11. Addicted? Reduced host resistance in populations with defensive symbionts

    Science.gov (United States)

    Cogni, Rodrigo; Cao, Chuan; Smith, Sophie; Illingworth, Christopher J. R.; Jiggins, Francis M.

    2016-01-01

    Heritable symbionts that protect their hosts from pathogens have been described in a wide range of insect species. By reducing the incidence or severity of infection, these symbionts have the potential to reduce the strength of selection on genes in the insect genome that increase resistance. Therefore, the presence of such symbionts may slow down the evolution of resistance. Here we investigated this idea by exposing Drosophila melanogaster populations to infection with the pathogenic Drosophila C virus (DCV) in the presence or absence of Wolbachia, a heritable symbiont of arthropods that confers protection against viruses. After nine generations of selection, we found that resistance to DCV had increased in all populations. However, in the presence of Wolbachia the resistant allele of pastrel—a gene that has a major effect on resistance to DCV—was at a lower frequency than in the symbiont-free populations. This finding suggests that defensive symbionts have the potential to hamper the evolution of insect resistance genes, potentially leading to a state of evolutionary addiction where the genetically susceptible insect host mostly relies on its symbiont to fight pathogens. PMID:27335421

  12. The symbiont side of symbiosis: do microbes really benefit?

    Directory of Open Access Journals (Sweden)

    Justine Rebecca Garcia

    2014-09-01

    Full Text Available Microbial associations are integral to all eukaryotes. Mutualism, the interaction of two species for the benefit of both, is an important aspect of microbial associations, with evidence that multicellular organisms in particular benefit from microbes. However, the microbe’s perspective has largely been ignored, and it is unknown whether most microbial symbionts benefit from their associations with hosts. It has been presumed that microbial symbionts receive host-derived nutrients or a competition-free environment with reduced predation, but there have been few empirical tests, or even critical assessments, of these assumptions. We evaluate these hypotheses based on available evidence, which indicate reduced competition and predation are not universal benefits for symbionts. Some symbionts do receive nutrients from their host, but this has not always been linked to a corresponding increase in symbiont fitness. We recommend experiments to test symbiont fitness using current experimental systems of symbiosis and detail considerations for other systems. Incorporating symbiont fitness into symbiosis research will provide insight into the evolution of mutualistic interactions and cooperation in general.

  13. Earthworm ecology affects the population structure of their Verminephrobacter symbionts

    DEFF Research Database (Denmark)

    Macedo Viana, Flavia Daniela; Jensen, Christopher Erik; Macey, Michael;

    2016-01-01

    from two contrasting ecological types of earthworm hosts: the high population density, fast reproducing compost worms, Eisenia andrei and E. fetida, and the low-density, slow reproducing Aporrectodea tuberculata, commonly found in garden soils; for both types, three distinct populations were...... investigated. Based on MLST of 193 Verminephrobacter isolates, the symbiont community in each worm individual was very homogeneous. The more solitary A. tuberculata carried unique symbiont populations in 9 out of 10 host individuals, whereas the symbiont populations in the social compost worms were homogeneous...

  14. The importance of gut symbionts in the development of the brown marmorated stink bug, Halyomorpha halys (Stal.

    Directory of Open Access Journals (Sweden)

    Christopher M Taylor

    Full Text Available The invasive brown marmorated stink bug, Halyomorpha halys (Stål, has become a severe agricultural pest and nuisance problem since its introduction in the U.S. Research is being conducted to understand its biology and to find management solutions. Its symbiotic relationship with gut symbionts is one aspect of its biology that is not understood. In the family Pentatomidae, the reliance on gut symbionts for successful development seems to vary depending on the species of stink bug. This research assessed the role of gut symbionts in the development, survivorship, and fecundity of H. halys. We compared various fitness parameters of nymphs and adults reared from surface sterilized and untreated egg masses during two consecutive generations under laboratory conditions. Results provided direct evidence that H. halys is negatively impacted by the prevention of vertical transmission of its gut symbionts and that this impact is significant in the first generation and manifests dramatically in the subsequent generation. Developmental time and survivorship of treated cohorts in the first generation were significantly affected during third instar development through to the adult stage. Adults from the sterilized treatment group exhibited longer pre-oviposition periods, produced fewer egg masses, had significantly smaller clutch sizes, and the hatch rate and survivorship of those eggs were significantly reduced. Observations following hatch of surface sterilized eggs also revealed significant effects on wandering behavior of the first instars. The second generation progeny from adults of the sterilized cohorts showed significantly lower survival to adulthood, averaging only 0.3% compared to 20.8% for the control cohorts. Taken together, results demonstrate that H. halys is heavily impacted by deprival of its gut symbionts. Given the economic status of this invasive pest, further investigations may lead to management tactics that disrupt this close symbiotic

  15. Horizontal transmission of attenuated strain A66 of duck hepatitis virus%鸭肝炎病毒A66弱毒株的水平传播感染

    Institute of Scientific and Technical Information of China (English)

    张小飞; 黄显明; 尹秀凤; 陆承平

    2011-01-01

    strain A66 by subcutaneous injection or oral administration was able to result in excretion of the virus through droppings. Cohabitated ducklings could be infected through fecal-oral route, and the infected animals could obtain certain protective immunity. However, the cohabitation infection capacity decreased gradually by the increase of cohabitation generations, and disappeared at the fifth generation. The results demonstrate that strain A66 can cause horizontal transmission of infection among ducklings, but the infection ability is limited and cannot result in reversion to virulence.

  16. Use of the Internal Transcribed Spacer (ITS Regions to Examine Symbiont Divergence and as a Diagnostic Tool for Sodalis-Related Bacteria

    Directory of Open Access Journals (Sweden)

    Rita V. M. Rio

    2011-11-01

    Full Text Available Bacteria excel in most ecological niches, including insect symbioses. A cluster of bacterial symbionts, established within a broad range of insects, share high 16S rRNA similarities with the secondary symbiont of the tsetse fly (Diptera: Glossinidae, Sodalis glossinidius. Although 16S rRNA has proven informative towards characterization of this clade, the gene is insufficient for examining recent divergence due to selective constraints. Here, we assess the application of the internal transcribed spacer (ITS regions, specifically the ITSglu and ITSala,ile, used in conjunction with 16S rRNA to enhance the phylogenetic resolution of Sodalis-allied bacteria. The 16S rRNA + ITS regions of Sodalis and allied bacteria demonstrated significant divergence and were robust towards phylogenetic resolution. A monophyletic clade of Sodalis isolates from tsetse species, distinct from other Enterobacteriaceae, was consistently observed suggesting diversification due to host adaptation. In contrast, the phylogenetic distribution of symbionts isolated from hippoboscid flies and various Hemiptera and Coleoptera were intertwined suggesting either horizontal transfer or a recent establishment from an environmental source. Lineage splitting of Sodalis-allied bacteria into symbiotic and free-living sister groups was also observed. Additionally, we propose an ITS region as a diagnostic marker for the identification of additional Sodalis-allied symbionts in the field. These results expand our knowledge of informative genome regions to assess genetic divergence since splitting from the last common ancestor, of this versatile insect symbiont clade that have become increasingly recognized as valuable towards our understanding of the evolution of symbiosis. These facultative and recently associated symbionts may provide a novel source of traits adaptable to the dynamic ecologies encountered by diverse host backgrounds.

  17. Symbiont modulates expression of specific gene categories in Angomonas deanei

    Directory of Open Access Journals (Sweden)

    Luciana Loureiro Penha

    Full Text Available Trypanosomatids are parasites that cause disease in humans, animals, and plants. Most are non-pathogenic and some harbor a symbiotic bacterium. Endosymbiosis is part of the evolutionary process of vital cell functions such as respiration and photosynthesis. Angomonas deanei is an example of a symbiont-containing trypanosomatid. In this paper, we sought to investigate how symbionts influence host cells by characterising and comparing the transcriptomes of the symbiont-containing A. deanei (wild type and the symbiont-free aposymbiotic strains. The comparison revealed that the presence of the symbiont modulates several differentially expressed genes. Empirical analysis of differential gene expression showed that 216 of the 7625 modulated genes were significantly changed. Finally, gene set enrichment analysis revealed that the largest categories of genes that downregulated in the absence of the symbiont were those involved in oxidation-reduction process, ATP hydrolysis coupled proton transport and glycolysis. In contrast, among the upregulated gene categories were those involved in proteolysis, microtubule-based movement, and cellular metabolic process. Our results provide valuable information for dissecting the mechanism of endosymbiosis in A. deanei.

  18. Contact and voter processes on the infinite percolation cluster as models of host-symbiont interactions

    CERN Document Server

    Bertacchi, Daniela; Zucca, Fabio

    2009-01-01

    We introduce spatially explicit stochastic processes to model multispecies hostsymbiont interactions. The host environment is static, modeled by the infinite percolation cluster of site percolation. Symbionts evolve on the infinite cluster through contact or voter type interactions, where each host may be infected by a colony of symbionts. In the presence of a single symbiont species, the condition for invasion as a function of the density of the habitat of hosts and the maximal size of the colonies is investigated in details. In the presence of multiple symbiont species, it is proved that the community of symbionts clusters in two dimensions whereas symbiont species may coexist in higher dimensions.

  19. Colonization of plant substrates at hydrothermal vents and cold seeps in the northeast Atlantic and Mediterranean and occurrence of symbiont-related bacteria

    Directory of Open Access Journals (Sweden)

    Kamil M Szafranski

    2015-02-01

    Full Text Available Reducing conditions with elevated sulphide and methane concentrations in ecosystems such as hydrothermal vents, cold seeps or organic falls, are suitable for chemosynthetic primary production. Understanding processes driving bacterial diversity, colonization and dispersal is of prime importance for deep-sea microbial ecology. This study provides a detailed characterization of bacterial assemblages colonizing plant-derived substrates using a standardised approach over a geographic area spanning the North-East Atlantic and Mediterranean. Wood and alfalfa substrates in colonization devices were deployed for different periods at 8 deep-sea chemosynthesis-based sites in 4 distinct geographic areas. Pyrosequencing of a fragment of the 16S rRNA-encoding gene was used to describe bacterial communities. Colonization occurred within the first 14 days. The diversity was higher in samples deployed for more than 289 days. After 289 days, no relation was observed between community richness and deployment duration, suggesting that diversity may have reached saturation sometime in between. Communities in long-term deployments were different, and their composition was mainly influenced by the geographical location where devices were deployed. Numerous sequences related to horizontally-transmitted chemosynthetic symbionts of metazoans were identified. Their potential status as free-living forms of these symbionts was evaluated based on sequence similarity and monophyly with demonstrated symbionts. Results suggest that some free-living forms of metazoan symbionts or their close relatives, such as the epsilonproteobacterium associated with the shrimp Rimicaris exoculata, are efficient colonizers of plant substrates at vents and seeps.

  20. Colonization of plant substrates at hydrothermal vents and cold seeps in the northeast Atlantic and Mediterranean and occurrence of symbiont-related bacteria.

    Science.gov (United States)

    Szafranski, Kamil M; Deschamps, Philippe; Cunha, Marina R; Gaudron, Sylvie M; Duperron, Sébastien

    2015-01-01

    Reducing conditions with elevated sulfide and methane concentrations in ecosystems such as hydrothermal vents, cold seeps or organic falls, are suitable for chemosynthetic primary production. Understanding processes driving bacterial diversity, colonization and dispersal is of prime importance for deep-sea microbial ecology. This study provides a detailed characterization of bacterial assemblages colonizing plant-derived substrates using a standardized approach over a geographic area spanning the North-East Atlantic and Mediterranean. Wood and alfalfa substrates in colonization devices were deployed for different periods at 8 deep-sea chemosynthesis-based sites in four distinct geographic areas. Pyrosequencing of a fragment of the 16S rRNA-encoding gene was used to describe bacterial communities. Colonization occurred within the first 14 days. The diversity was higher in samples deployed for more than 289 days. After 289 days, no relation was observed between community richness and deployment duration, suggesting that diversity may have reached saturation sometime in between. Communities in long-term deployments were different, and their composition was mainly influenced by the geographical location where devices were deployed. Numerous sequences related to horizontally-transmitted chemosynthetic symbionts of metazoans were identified. Their potential status as free-living forms of these symbionts was evaluated based on sequence similarity with demonstrated symbionts. Results suggest that some free-living forms of metazoan symbionts or their close relatives, such as Epsilonproteobacteria associated with the shrimp Rimicaris exoculata, are efficient colonizers of plant substrates at vents and seeps.

  1. Drosophila Adaptation to Viral Infection through Defensive Symbiont Evolution

    Science.gov (United States)

    Faria, Vitor G.; Magalhães, Sara; Paulo, Tânia F.; Nolte, Viola; Schlötterer, Christian

    2016-01-01

    Microbial symbionts can modulate host interactions with biotic and abiotic factors. Such interactions may affect the evolutionary trajectories of both host and symbiont. Wolbachia protects Drosophila melanogaster against several viral infections and the strength of the protection varies between variants of this endosymbiont. Since Wolbachia is maternally transmitted, its fitness depends on the fitness of its host. Therefore, Wolbachia populations may be under selection when Drosophila is subjected to viral infection. Here we show that in D. melanogaster populations selected for increased survival upon infection with Drosophila C virus there is a strong selection coefficient for specific Wolbachia variants, leading to their fixation. Flies carrying these selected Wolbachia variants have higher survival and fertility upon viral infection when compared to flies with the other variants. These findings demonstrate how the interaction of a host with pathogens shapes the genetic composition of symbiont populations. Furthermore, host adaptation can result from the evolution of its symbionts, with host and symbiont functioning as a single evolutionary unit. PMID:27684942

  2. Host-Symbiont Interactions for Potentially Managing Heteropteran Pests

    Directory of Open Access Journals (Sweden)

    Simone Souza Prado

    2012-01-01

    Full Text Available Insects in the suborder Heteroptera, the so-called true bugs, include over 40,000 species worldwide. This insect group includes many important agricultural pests and disease vectors, which often have bacterial symbionts associated with them. Some symbionts have coevolved with their hosts to the extent that host fitness is compromised with the removal or alteration of their symbiont. The first bug/microbial interactions were discovered over 50 years ago. Only recently, mainly due to advances in molecular techniques, has the nature of these associations become clearer. Some researchers have pursued the genetic modification (paratransgenesis of symbionts for disease control or pest management. With the increasing interest and understanding of the bug/symbiont associations and their ecological and physiological features, it will only be a matter of time before pest/vector control programs utilize this information and technique. This paper will focus on recent discoveries of the major symbiotic systems in Heteroptera, highlighting how the understanding of the evolutionary and biological aspects of these relationships may lead to the development of alternative techniques for efficient heteropteran pest control and suppression of diseases vectored by Heteroptera.

  3. The Brucella suis Genome Reveals Fundamental Similarities between Animal and Plant Pathogens and Symbionts

    National Research Council Canada - National Science Library

    Ian T. Paulsen; Rekha Seshadri; Karen E. Nelson; Jonathan A. Eisen; John F. Heidelberg; Timothy D. Read; Robert J. Dodson; Lowell Umayam; Lauren M. Brinkac; Maureen J. Beanan; Sean C. Daugherty; Robert T. Deboy; A. Scott Durkin; James F. Kolonay; Ramana Madupu; William C. Nelson; Bola Ayodeji; Margaret Kraul; Jyoti Shetty; Joel Malek; Susan E. van Aken; Steven Riedmuller; Herve Tettelin; Steven R. Gill; Owen White; Steven L. Salzberg; David L. Hoover; Luther E. Lindler; Shirley M. Halling; Stephen M. Boyle; Claire M. Fraser

    2002-01-01

    .... Extensive gene synteny between B. suis chromosome 1 and the genome of the plant symbiont Mesorhizobium loti emphasizes the similarity between this animal pathogen and plant pathogens and symbionts...

  4. Metagenomic Analysis of Microbial Symbionts in a Gutless Worm

    Energy Technology Data Exchange (ETDEWEB)

    Woyke, Tanja; Teeling, Hanno; Ivanova, Natalia N.; Hunteman, Marcel; Richter, Michael; Gloeckner, Frank Oliver; Boeffelli, Dario; Barry, Kerrie W.; Shapiro, Harris J.; Anderson, Iain J.; Szeto, Ernest; Kyrpides, Nikos C.; Mussmann, Marc; Amann, Rudolf; Bergin, Claudia; Ruehland, Caroline; Rubin, Edward M.; Dubilier, Nicole

    2006-05-01

    Symbioses between bacteria and eukaryotes are ubiquitous, yet our understanding of the interactions driving these associations is hampered by our inability to cultivate most host-associated microbes. Here we use a metagenomic approach to describe four co-occurring symbionts from the marine oligochaete Olavius algarvensis, a worm lacking a mouth, gut and nephridia. Shotgun sequencing and metabolic pathway reconstruction revealed that the symbionts are sulphur-oxidizing and sulphate-reducing bacteria, all of which are capable of carbon fixation, thus providing the host with multiple sources of nutrition. Molecular evidence for the uptake and recycling of worm waste products by the symbionts suggests how the worm could eliminate its excretory system, an adaptation unique among annelid worms. We propose a model that describes how the versatile metabolism within this symbiotic consortium provides the host with an optimal energy supply as it shuttles between the upper oxic and lower anoxic coastal sediments that it inhabits.

  5. Symbionts commonly provide broad spectrum resistance to viruses in insects: a comparative analysis of Wolbachia strains.

    Science.gov (United States)

    Martinez, Julien; Longdon, Ben; Bauer, Simone; Chan, Yuk-Sang; Miller, Wolfgang J; Bourtzis, Kostas; Teixeira, Luis; Jiggins, Francis M

    2014-09-01

    In the last decade, bacterial symbionts have been shown to play an important role in protecting hosts against pathogens. Wolbachia, a widespread symbiont in arthropods, can protect Drosophila and mosquito species against viral infections. We have investigated antiviral protection in 19 Wolbachia strains originating from 16 Drosophila species after transfer into the same genotype of Drosophila simulans. We found that approximately half of the strains protected against two RNA viruses. Given that 40% of terrestrial arthropod species are estimated to harbour Wolbachia, as many as a fifth of all arthropods species may benefit from Wolbachia-mediated protection. The level of protection against two distantly related RNA viruses--DCV and FHV--was strongly genetically correlated, which suggests that there is a single mechanism of protection with broad specificity. Furthermore, Wolbachia is making flies resistant to viruses, as increases in survival can be largely explained by reductions in viral titer. Variation in the level of antiviral protection provided by different Wolbachia strains is strongly genetically correlated to the density of the bacteria strains in host tissues. We found no support for two previously proposed mechanisms of Wolbachia-mediated protection--activation of the immune system and upregulation of the methyltransferase Dnmt2. The large variation in Wolbachia's antiviral properties highlights the need to carefully select Wolbachia strains introduced into mosquito populations to prevent the transmission of arboviruses.

  6. Symbionts commonly provide broad spectrum resistance to viruses in insects: a comparative analysis of Wolbachia strains.

    Directory of Open Access Journals (Sweden)

    Julien Martinez

    2014-09-01

    Full Text Available In the last decade, bacterial symbionts have been shown to play an important role in protecting hosts against pathogens. Wolbachia, a widespread symbiont in arthropods, can protect Drosophila and mosquito species against viral infections. We have investigated antiviral protection in 19 Wolbachia strains originating from 16 Drosophila species after transfer into the same genotype of Drosophila simulans. We found that approximately half of the strains protected against two RNA viruses. Given that 40% of terrestrial arthropod species are estimated to harbour Wolbachia, as many as a fifth of all arthropods species may benefit from Wolbachia-mediated protection. The level of protection against two distantly related RNA viruses--DCV and FHV--was strongly genetically correlated, which suggests that there is a single mechanism of protection with broad specificity. Furthermore, Wolbachia is making flies resistant to viruses, as increases in survival can be largely explained by reductions in viral titer. Variation in the level of antiviral protection provided by different Wolbachia strains is strongly genetically correlated to the density of the bacteria strains in host tissues. We found no support for two previously proposed mechanisms of Wolbachia-mediated protection--activation of the immune system and upregulation of the methyltransferase Dnmt2. The large variation in Wolbachia's antiviral properties highlights the need to carefully select Wolbachia strains introduced into mosquito populations to prevent the transmission of arboviruses.

  7. Human symbionts inject and neutralize antibacterial toxins to persist in the gut.

    Science.gov (United States)

    Wexler, Aaron G; Bao, Yiqiao; Whitney, John C; Bobay, Louis-Marie; Xavier, Joao B; Schofield, Whitman B; Barry, Natasha A; Russell, Alistair B; Tran, Bao Q; Goo, Young Ah; Goodlett, David R; Ochman, Howard; Mougous, Joseph D; Goodman, Andrew L

    2016-03-29

    The human gut microbiome is a dynamic and densely populated microbial community that can provide important benefits to its host. Cooperation and competition for nutrients among its constituents only partially explain community composition and interpersonal variation. Notably, certain human-associated Bacteroidetes--one of two major phyla in the gut--also encode machinery for contact-dependent interbacterial antagonism, but its impact within gut microbial communities remains unknown. Here we report that prominent human gut symbionts persist in the gut through continuous attack on their immediate neighbors. Our analysis of just one of the hundreds of species in these communities reveals 12 candidate antibacterial effector loci that can exist in 32 combinations. Through the use of secretome studies, in vitro bacterial interaction assays and multiple mouse models, we uncover strain-specific effector/immunity repertoires that can predict interbacterial interactions in vitro and in vivo, and find that some of these strains avoid contact-dependent killing by accumulating immunity genes to effectors that they do not encode. Effector transmission rates in live animals can exceed 1 billion events per minute per gram of colonic contents, and multiphylum communities of human gut commensals can partially protect sensitive strains from these attacks. Together, these results suggest that gut microbes can determine their interactions through direct contact. An understanding of the strategies human gut symbionts have evolved to target other members of this community may provide new approaches for microbiome manipulation.

  8. Horizontal drilling in Ontario

    Energy Technology Data Exchange (ETDEWEB)

    Sidey, P.; Precul, L. [Sproule Associates Ltd., Calgary, AB (Canada)

    2002-07-01

    A review of oil and gas production in Ontario was presented with particular reference to drilling activity between 1987 to mid 2002 when 1450 vertical wells were drilled, of which 1100 were for petroleum production and the remainder were for gas storage, observation wells, private gas wells and stratigraphic tests. Of the 1100 vertical wells drilled for petroleum production, 40 per cent became gas wells, 16 per cent became oil wells, 4 per cent became oil and gas wells, and 40 per cent were dry. During the same time period, 133 horizontal wells were also drilled, mostly for petroleum. The most active operator was Talisman Energy, which drilled 101 of the 133 horizontal wells. The remainder were drilled by 12 other companies. Of the horizontal wells, 64 per cent became oil wells, 19 per cent became gas wells, and 17 per cent were dry. This presentation included graphs depicting which oil and gas pools saw vertical or horizontal drilling during the designated time period, and explained how the wells were classified. Both horizontal and vertical well targets were illustrated. Particular reference was made to Talisman Energy's Lake Erie Drilling program which revealed that horizontal wells have an initial production rate that is 5 times that expected from vertical wells. The Hillman Pool case study revealed that the initial rate of the average horizontal well is less than half that of the average vertical well. Horizontal drilling in the Lake Erie Morpeth Gas pool has also been a commercial success. This paper demonstrates that operators have maintained Ontario's oil and gas production at high levels. In 1997 widespread horizontal drilling began taking place in Ontario, and since then, approximately 30 per cent of the wells drilled in the province have been horizontal. 16 figs.

  9. Physical proximity may promote lateral acquisition of bacterial symbionts in vesicomyid clams.

    Directory of Open Access Journals (Sweden)

    Carole Decker

    Full Text Available Vesicomyid clams harbor intracellular sulfur-oxidizing bacteria that are predominantly maternally inherited and co-speciate with their hosts. Genome recombination and the occurrence of non-parental strains were recently demonstrated in symbionts. However, mechanisms favoring such events remain to be identified. In this study, we investigated symbionts in two phylogenetically distant vesicomyid species, Christineconcha regab and Laubiericoncha chuni, which sometimes co-occur at a cold-seep site in the Gulf of Guinea. We showed that each of the two species harbored a single dominant bacterial symbiont strain. However, for both vesicomyid species, the symbiont from the other species was occasionally detected in the gills using fluorescence in situ hybridization and gene sequences analyses based on six symbiont marker genes. Symbiont strains co-occurred within a single host only at sites where both host species were found; whereas one single symbiont strain was detected in C. regab specimens from a site where no L. chuni individuals had been observed. These results suggest that physical proximity favored the acquisition of non-parental symbiont strains in Vesicomyidae. Over evolutionary time, this could potentially lead to genetic exchanges among symbiont species and eventually symbiont displacement. Symbiont densities estimated using 3D fluorescence in situ hybridization varied among host species and sites, suggesting flexibility in the association despite the fact that a similar type of metabolism is expected in all symbionts.

  10. Evolutionary replacement of obligate symbionts in an ancient and diverse insect lineage.

    Science.gov (United States)

    Koga, Ryuichi; Bennett, Gordon M; Cryan, Jason R; Moran, Nancy A

    2013-07-01

    Many insect groups depend on ancient obligate symbioses with bacteria that undergo long-term genomic degradation due to inactivation and loss of ancestral genes. Sap-feeding insects in the hemipteran suborder Auchenorrhyncha show complex symbioses with at least two obligate bacterial symbionts, inhabiting specialized host cells (bacteriocytes). We explored the symbiotic relationships of the spittlebugs (Auchenorrhyncha: Cercopoidea) using phylogenetic and microscopy methods. Results show that most spittlebugs contain the symbionts Sulcia muelleri (Bacteroidetes) and Zinderia insecticola (Betaproteobacteria) with each restricted to its own bacteriocyte type. However, the ancestral Zinderia symbiont has been replaced with a novel symbiont closely related to Sodalis glossinidius (Enterobacteriaceae) in members of the ecologically successful spittlebug tribe Philaenini. At least one spittlebug species retains Sulcia and Zinderia, but also has acquired a Sodalis-like symbiont, possibly representing a transitional stage in the evolutionary succession of symbioses. Phylogenetic analyses including symbionts of other Auchenorrhyncha lineages suggest that Zinderia, like Sulcia, descends from an ancestral symbiont present in the common ancestor of Auchenorrhyncha. This betaproteobacterial symbiont has been repeatedly replaced by other symbionts, such as the Sodalis-like symbiont of spittlebugs. Symbiont replacement may offer a route for hosts to escape dependence on an ancient, degraded and potentially inefficient symbiont. © 2013 John Wiley & Sons Ltd and Society for Applied Microbiology.

  11. Ankyrin-repeat proteins from sponge symbionts modulate amoebal phagocytosis.

    Science.gov (United States)

    Nguyen, Mary T H D; Liu, Michael; Thomas, Torsten

    2014-03-01

    Bacteria-eukaryote symbiosis occurs in all stages of evolution, from simple amoebae to mammals, and from facultative to obligate associations. Sponges are ancient metazoans that form intimate symbiotic interactions with complex communities of bacteria. The basic nutritional requirements of the sponge are in part satisfied by the phagocytosis of bacterial food particles from the surrounding water. How bacterial symbionts, which are permanently associated with the sponge, survive in the presence of phagocytic cells is largely unknown. Here, we present the discovery of a genomic fragment from an uncultured gamma-proteobacterial sponge symbiont that encodes for four proteins, whose closest known relatives are found in a sponge genome. Through recombinant approaches, we show that these four eukaryotic-like, ankyrin-repeat proteins (ARP) when expressed in Eschericha coli can modulate phagocytosis of amoebal cells and lead to accumulation of bacteria in the phagosome. Mechanistically, two ARPs appear to interfere with phagosome development in a similar way to reduced vacuole acidification, by blocking the fusion of the early phagosome with the lysosome and its digestive enzymes. Our results show that ARP from sponge symbionts can function to interfere with phagocytosis, and we postulate that this might be one mechanism by which symbionts can escape digestion in a sponge host.

  12. Understanding nutrient exchange between Azolla and its symbiont, Nostoc

    OpenAIRE

    Eily, Ariana

    2017-01-01

    This is an in-depth look at the research I am doing for my doctoral degree at Duke University, investigating the exchange of nutrients between the aquatic fern genus, Azolla, and its cyanobacterial symbiont, Nostoc azollae. All of the illustrations and microscopy images within this presentation are my own.

  13. Complete Genome Sequence of the Human Gut Symbiont Roseburia hominis

    DEFF Research Database (Denmark)

    Travis, Anthony J.; Kelly, Denise; Flint, Harry J;

    2015-01-01

    We report here the complete genome sequence of the human gut symbiont Roseburia hominis A2-183(T) (= DSM 16839(T) = NCIMB 14029(T)), isolated from human feces. The genome is represented by a 3,592,125-bp chromosome with 3,405 coding sequences. A number of potential functions contributing to host-...

  14. Highly infectious symbiont dominates initial uptake in coral juveniles.

    Science.gov (United States)

    Abrego, David; VAN Oppen, Madeleine J H; Willis, Bette L

    2009-08-01

    The majority of reef-building corals acquire their obligate algal symbionts (Symbiodinium) from the environment. However, factors shaping the initial establishment of coral-algal symbioses, including parental effects, local environmental conditions and local availability of symbionts, are not well understood. This study monitored the uptake and maintenance of Symbiodinium in juveniles of two common corals, Acropora tenuis and Acropora millepora, that were reciprocally explanted between sites where adult colonies host different types of Symbiodinium. We found that coral juveniles were rapidly dominated by type D Symbiodinium, even though this type is not found in adult colonies (including the parental colonies) in four out of the five study populations. Furthermore, type D Symbiodinium was found in less than one-third of a wide range of coral species (n > 50) sampled at the two main study sites, suggesting that its dominance in the acroporid juveniles is not because it is the most abundant local endosymbiotic type. Moreover, dominance by type D was observed irrespective of the light intensity to which juveniles were exposed in a field study. In summary, despite its relatively low abundance in coral assemblages at the study sites and irrespective of the surrounding light environment, type D Symbiodinium is the main symbiont type initially acquired by juveniles of A. millepora and A. tenuis. We conclude that during early ontogeny in these corals, there are few barriers to the uptake of Symbiodinium types which differ from those found in parental colonies, resulting in dominance by a highly infectious and potentially opportunistic symbiont.

  15. A nuptially transmitted Ichthyosproean symbiont of Tenebrio molitor (Coleoptera: Tenebrionidae)

    Science.gov (United States)

    The yellow mealworm, Tenebrio molitor, harbors a symbiont that has spores with a thick, laminated wall and infects the fat body and ventral nerve chord of adult and larval beetles. In adult males, there is heavy infection of the epithelial cells of the testes and between testes lobes with occasional...

  16. Think laterally: horizontal gene transfer from symbiotic microbes may extend the phenotype of marine sessile hosts

    Directory of Open Access Journals (Sweden)

    Sandie M Degnan

    2014-11-01

    Full Text Available Since the origin of the animal kingdom, marine animals have lived in association with viruses, prokaryotes and unicellular eukaryotes, often as symbionts. This long and continuous interaction has provided ample opportunity not only for the evolution of intimate interactions such as sharing of metabolic pathways, but also for horizontal gene transfer (HGT of non-metazoan genes into metazoan genomes. The number of demonstrated cases of inter-kingdom HGT is currently small, such that it is not yet widely appreciated as a significant player in animal evolution. Sessile marine invertebrates that vertically inherit bacterial symbionts, that have no dedicated germ line, or that bud or excise pluripotent somatic cells during their life history may be particularly receptive to HGT from their symbionts. Closer scrutiny of the growing number of genomes being accrued for these animals may thus reveal HGT as a regular source of novel variation that can function to extend the host phenotype metabolically, morphologically or even behaviourally. Taxonomic identification of symbionts will help to address the intriguing question of whether past HGT events may constrain contemporary symbioses.

  17. Estudio del horizonte local

    OpenAIRE

    Ros Ferré, Rosa Maria

    2009-01-01

    El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical).

  18. Fungal symbionts alter plant responses to global change.

    Science.gov (United States)

    Kivlin, Stephanie N; Emery, Sarah M; Rudgers, Jennifer A

    2013-07-01

    While direct plant responses to global change have been well characterized, indirect plant responses to global change, via altered species interactions, have received less attention. Here, we examined how plants associated with four classes of fungal symbionts (class I leaf endophytes [EF], arbuscular mycorrhizal fungi [AMF], ectomycorrhizal fungi [ECM], and dark septate endophytes [DSE]) responded to four global change factors (enriched CO2, drought, N deposition, and warming). We performed a meta-analysis of 434 studies spanning 174 publications to search for generalizable trends in responses of plant-fungal symbioses to future environments. Specifically, we addressed the following questions: (1) Can fungal symbionts ameliorate responses of plants to global change? (2) Do fungal symbiont groups differ in the degree to which they modify plant response to global change? (3) Do particular global change factors affect plant-fungal symbioses more than others? In all global change scenarios, except elevated CO2, fungal symbionts significantly altered plant responses to global change. In most cases, fungal symbionts increased plant biomass in response to global change. However, increased N deposition reduced the benefits of symbiosis. Of the global change factors we considered, drought and N deposition resulted in the strongest fungal mediation of plant responses. Our analysis highlighted gaps in current knowledge for responses of particular fungal groups and revealed the importance of considering not only the nonadditive effects of multiple global change factors, but also the interactive effects of multiple fungal symbioses. Our results show that considering plant-fungal symbioses is critical to predicting ecosystem response to global change.

  19. Cryptic diversity and symbiont interactions in rock-posy lichens.

    Science.gov (United States)

    Leavitt, Steven D; Kraichak, Ekaphan; Vondrak, Jan; Nelsen, Matthew P; Sohrabi, Mohammad; Perez-Ortega, Sergio; St Clair, Larry L; Lumbsch, H Thorsten

    2016-06-01

    Identifying factors that influence species interactions is central to research in symbiotic systems. While lichens represent iconic models of symbiosis and play important roles in understanding the biology of symbiotic interactions, patterns of interactions in lichen symbionts and mechanisms governing these relationships are not well characterized. This is due, in part to the fact that current taxonomic approaches for recognizing diversity in lichen symbionts commonly fail to accurately reflect actual species diversity. In this study, we employed DNA-based approaches to circumscribed candidate species-level lineages in rock-posy lichen symbionts (mycobiont=Rhizoplaca s. lat. species; photobiont=Trebouxia species). Our results revealed a high degree of cryptic diversity in both the myco- and photobionts in these lichens. Using the candidate species circumscribed here, we investigated the specificity of the symbionts toward their partners and inferred the relative importance of various factors influencing symbiont interactions. Distinct mycobiont species complexes, ecozones, and biomes are significantly correlated with the occurrence of photobiont OTUs, indicating that complex interactions among mycobiont lineages, ecogeography, and microhabitat determine interactions between photobionts and their mycobionts in lichen symbiosis. One-to-one specificity between mycobiont and photobiont species was not found, with the exception of R. maheui that associated with a single Trebouxia OTU that was not found with other Rhizoplaca s. lat. species. We estimated the most recent common ancestor of the core Rhizoplaca group at c. 62.5Ma, similar in age to the diverse parmelioid core group in the well-studied family Parmeliaceae. However, in contrast to Parmeliaceae, species in Rhizoplaca were found to associate with a narrow range of photobionts. Our study provides important perspectives into species diversity and interactions in iconic lichen symbiotic systems and establishes a

  20. Environmental symbiont acquisition may not be the solution to warming seas for reef-building corals.

    Directory of Open Access Journals (Sweden)

    Mary Alice Coffroth

    Full Text Available BACKGROUND: Coral reefs worldwide are in decline. Much of the mortality can be attributed to coral bleaching (loss of the coral's intracellular photosynthetic algal symbiont associated with global warming. How corals will respond to increasing oceanic temperatures has been an area of extensive study and debate. Recovery after a bleaching event is dependent on regaining symbionts, but the source of repopulating symbionts is poorly understood. Possibilities include recovery from the proliferation of endogenous symbionts or recovery by uptake of exogenous stress-tolerant symbionts. METHODOLOGY/PRINCIPAL FINDINGS: To test one of these possibilities, the ability of corals to acquire exogenous symbionts, bleached colonies of Porites divaricata were exposed to symbiont types not normally found within this coral and symbiont acquisition was monitored. After three weeks exposure to exogenous symbionts, these novel symbionts were detected in some of the recovering corals, providing the first experimental evidence that scleractinian corals are capable of temporarily acquiring symbionts from the water column after bleaching. However, the acquisition was transient, indicating that the new symbioses were unstable. Only those symbiont types present before bleaching were stable upon recovery, demonstrating that recovery was from the resident in situ symbiont populations. CONCLUSIONS/SIGNIFICANCE: These findings suggest that some corals do not have the ability to adjust to climate warming by acquiring and maintaining exogenous, more stress-tolerant symbionts. This has serious ramifications for the success of coral reefs and surrounding ecosystems and suggests that unless actions are taken to reverse it, climate change will lead to decreases in biodiversity and a loss of coral reefs.

  1. Sliding Downhill Horizontally

    Science.gov (United States)

    Zurcher, Ulrich

    2005-04-01

    We study the motion of object sliding on a rough incline plane. The coefficient of kinetic friction between the surface and the object is such that the magnitude of the gravitational force along the incline F is equal to the magnitude of the kinetic friction S. If the initial velocity of the object is along the incline, the object slides down the incline with constant velocity. We study the case when the object in launched in horizontal direction. We derive exact expressions for the terminal speed of the object and the maximum horizontal displacement of the object.

  2. Differential temporal changes of primary and secondary bacterial symbionts and whitefly host fitness following antibiotic treatments

    Science.gov (United States)

    Zhang, Chang-Rong; Shan, Hong-Wei; Xiao, Na; Zhang, Fan-Di; Wang, Xiao-Wei; Liu, Yin-Quan; Liu, Shu-Sheng

    2015-01-01

    Where multiple symbionts coexist in the same host, the selective elimination of a specific symbiont may enable the roles of a given symbiont to be investigated. We treated the Mediterranean species of the whitefly Bemisia tabaci complex by oral delivery of the antibiotic rifampicin, and then examined the temporal changes of its primary symbiont “Candidatus Portiera aleyrodidarum” and secondary symbiont “Ca. Hamiltonella defensa” as well as host fitness for three generations. In adults treated with rifampicin (F0), the secondary symbiont was rapidly reduced, approaching complete disappearance as adults aged. In contrast, the primary symbiont was little affected until later in the adult life. In the offspring of these adults (F1), both symbionts were significantly reduced and barely detectable when the hosts reached the adult stage. The F1 adults laid few eggs (F2), all of which failed to hatch. Mating experiments illustrated that the negative effects of rifampicin on host fitness were exerted via female hosts but not males. This study provides the first evidence of differential temporal reductions of primary and secondary symbionts in whiteflies following an antibiotic treatment. Studies that disrupt functions of bacterial symbionts must consider their temporal changes. PMID:26510682

  3. From parent to gamete: vertical transmission of Symbiodinium (Dinophyceae) ITS2 sequence assemblages in the reef building coral Montipora capitata.

    Science.gov (United States)

    Padilla-Gamiño, Jacqueline L; Pochon, Xavier; Bird, Christopher; Concepcion, Gregory T; Gates, Ruth D

    2012-01-01

    Parental effects are ubiquitous in nature and in many organisms play a particularly critical role in the transfer of symbionts across generations; however, their influence and relative importance in the marine environment has rarely been considered. Coral reefs are biologically diverse and productive marine ecosystems, whose success is framed by symbiosis between reef-building corals and unicellular dinoflagellates in the genus Symbiodinium. Many corals produce aposymbiotic larvae that are infected by Symbiodinium from the environment (horizontal transmission), which allows for the acquisition of new endosymbionts (different from their parents) each generation. In the remaining species, Symbiodinium are transmitted directly from parent to offspring via eggs (vertical transmission), a mechanism that perpetuates the relationship between some or all of the Symbiodinium diversity found in the parent through multiple generations. Here we examine vertical transmission in the Hawaiian coral Montipora capitata by comparing the Symbiodinium ITS2 sequence assemblages in parent colonies and the eggs they produce. Parental effects on sequence assemblages in eggs are explored in the context of the coral genotype, colony morphology, and the environment of parent colonies. Our results indicate that ITS2 sequence assemblages in eggs are generally similar to their parents, and patterns in parental assemblages are different, and reflect environmental conditions, but not colony morphology or coral genotype. We conclude that eggs released by parent colonies during mass spawning events are seeded with different ITS2 sequence assemblages, which encompass phylogenetic variability that may have profound implications for the development, settlement and survival of coral offspring.

  4. From parent to gamete: vertical transmission of Symbiodinium (Dinophyceae ITS2 sequence assemblages in the reef building coral Montipora capitata.

    Directory of Open Access Journals (Sweden)

    Jacqueline L Padilla-Gamiño

    Full Text Available Parental effects are ubiquitous in nature and in many organisms play a particularly critical role in the transfer of symbionts across generations; however, their influence and relative importance in the marine environment has rarely been considered. Coral reefs are biologically diverse and productive marine ecosystems, whose success is framed by symbiosis between reef-building corals and unicellular dinoflagellates in the genus Symbiodinium. Many corals produce aposymbiotic larvae that are infected by Symbiodinium from the environment (horizontal transmission, which allows for the acquisition of new endosymbionts (different from their parents each generation. In the remaining species, Symbiodinium are transmitted directly from parent to offspring via eggs (vertical transmission, a mechanism that perpetuates the relationship between some or all of the Symbiodinium diversity found in the parent through multiple generations. Here we examine vertical transmission in the Hawaiian coral Montipora capitata by comparing the Symbiodinium ITS2 sequence assemblages in parent colonies and the eggs they produce. Parental effects on sequence assemblages in eggs are explored in the context of the coral genotype, colony morphology, and the environment of parent colonies. Our results indicate that ITS2 sequence assemblages in eggs are generally similar to their parents, and patterns in parental assemblages are different, and reflect environmental conditions, but not colony morphology or coral genotype. We conclude that eggs released by parent colonies during mass spawning events are seeded with different ITS2 sequence assemblages, which encompass phylogenetic variability that may have profound implications for the development, settlement and survival of coral offspring.

  5. Is there a role for symbiotic bacteria in plant virus transmission?

    Science.gov (United States)

    During the process of circulative plant virus transmission by insect vectors, viruses interact with different insect vector tissues prior to transmission to a new host plant. An area of intense debate in the field is whether bacterial symbionts of insect vectors are involved in the virus transmissi...

  6. A nuptially transmitted ichthyosporean symbiont of Tenebrio molitor (Coleoptera: Tenebrionidae).

    Science.gov (United States)

    Lord, Jeffrey C; Hartzer, Kris L; Kambhampati, Srinivas

    2012-01-01

    The yellow mealworm, Tenebrio molitor, harbors a symbiont that has spores with a thick, laminated wall and infects the fat body and ventral nerve chord of adult and larval beetles. In adult males, there is heavy infection of the epithelial cells of the testes and between testes lobes with occasional penetration of the lobes. Spores are enveloped in the spermatophores when they are formed at the time of mating and transferred to the female's bursa copulatrix. Infection has not been found in the ovaries. The sequence of the nuclear small subunit rDNA indicates that the symbiont is a member of the Ichthyosporea, a class of protists near the animal-fungi divergence.

  7. Genomics of "Candidatus Synechococcus spongiarium", a Cyanobacterial Sponge Symbiont

    Energy Technology Data Exchange (ETDEWEB)

    Slaby, Beate M. [Univ. of Wuerzburg (Germany); Copeland, Alex [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Woyke, Tanja [Lawrence Berkeley National Lab. (LBNL), Walnut Creek, CA (United States). Dept. of Energy Joint Genome Inst.; Hentschel, Ute [Univ. of Wuerzburg (Germany)

    2014-03-21

    Marine sponges (Porifera): ancient metazoans of ecological importance, that produce bioactive secondary metabolites and interact with various microorganisms including cyanobacteria1: Marine Synechococcus spp.: cyanobacteria, important contributors to the global carbon cycle and major primary producers in the oceans2 Ca. S. spongiarum: an ecotype of this genus, widespread and abundant symbiont of various marine sponges around the world3, e.g. Aplysina aerophoba

  8. Bacterial and fungal symbionts of parasitic Dendroctonus bark beetles.

    Science.gov (United States)

    Dohet, Loïc; Grégoire, Jean-Claude; Berasategui, Aileen; Kaltenpoth, Martin; Biedermann, Peter H W

    2016-09-01

    Bark beetles (Curculionidae: Scolytinae) are one of the most species-rich herbivorous insect groups with many shifts in ecology and host-plant use, which may be mediated by their bacterial and fungal symbionts. While symbionts are well studied in economically important, tree-killing species, little is known about parasitic species whose broods develop in living trees. Here, using culture-dependent and independent methods, we provide a comprehensive overview of the associated bacteria, yeasts and filamentous fungi of the parasitic Dendroctonus micans, D. punctatus and D. valens, and compare them to those of other tree-inhabiting insects. Despite inhabiting different geographical regions and/or host trees, the three species showed similar microbial communities. Enterobacteria were the most prevalent bacteria, in particular Rahnella, Pantoea and Ewingella, in addition to Streptomyces Likewise, the yeasts Candida/Cyberlindnera were the most prominent fungi. All these microorganisms are widespread among tree-inhabiting insects with various ecologies, but their high prevalence overall might indicate a beneficial role such as detoxification of tree defenses, diet supplementation or protection against pathogens. As such, our results enable comparisons of symbiont communities of parasitic bark beetles with those of other beetles, and will contribute to our understanding of how microbial symbioses facilitate dietary shifts in insects.

  9. Gymnoxanthella radiolariae gen. et sp. nov. (Dinophyceae), a dinoflagellate symbiont from solitary polycystine radiolarians.

    Science.gov (United States)

    Yuasa, Tomoko; Horiguchi, Takeo; Mayama, Shigeki; Takahashi, Osamu

    2016-02-01

    The symbiotic dinoflagellate Gymnoxanthella radiolariae T. Yuasa et T. Horiguchi gen. et sp. nov. isolated from polycystine radiolarians is described herein based on light, scanning and transmission electron microscopy as well as molecular phylogenetic analyses of SSU and LSU rDNA sequences. Motile cells of G. radiolariae were obtained in culture, and appeared to be unarmored. The cells were 9.1-11.4 μm long and 5.7-9.4 μm wide, and oval to elongate oval in the ventral view. They possessed an counterclockwise horseshoe-shaped apical groove, a nuclear envelope with vesicular chambers, cingulum displacement with one cingulum width, and the nuclear fibrous connective; all of these are characteristics of Gymnodinium sensu stricto (Gymnodinium s.s.). Molecular phylogenetic analyses also indicated that G. radiolariae belongs to the clade of Gymnodinium s.s. However, in our molecular phylogenetic trees, G. radiolariae was distantly related to Gymnodinium fuscum, the type species of Gymnodinium. Based on the consistent morphological, genetic, and ecological divergence of our species with the other genera and species of Gymnodinium s.s., we considered it justified to erect a new, separate genus and species G. radiolariae gen. et sp. nov. As for the peridinioid symbiont of radiolarians, Brandtodinium has been erected as a new genus instead of Zooxanthella, but the name Zooxanthella is still valid. Brandtodinium is a junior synonym of Zooxanthella. Our results suggest that at least two dinoflagellate symbiont species, peridinioid Zooxanthella nutricula and gymnodinioid G. radiolariae, exist in radiolarians, and that they may have been mixed and reported as "Z. nutricula" since the 19th century.

  10. Horizontal Connection and Horizontal Mean Curvature in Carnot Groups

    Institute of Scientific and Technical Information of China (English)

    Kang Hai TAN; Xiao Ping YANG

    2006-01-01

    In this paper we give a geometric interpretation of the notion of the horizontal mean curvature which is introduced by Danielli-Garofalo-Nhieu and Pauls who recently introduced sub-Riemannian minimal surfaces in Carnot groups. This will be done by introducing a natural nonholonomic connection which is the restriction (projection) of the natural Riemannian connection on the horizontal bundle. For this nonholonomic connection and (intrinsic) regular hypersurfaces we introduce the notions of the horizontal second fundamental form and the horizontal shape operator. It turns out that the horizontal mean curvature is the trace of the horizontal shape operator.

  11. Studying the Complex Communities of Ants and Their Symbionts Using Ecological Network Analysis.

    Science.gov (United States)

    Ivens, Aniek B F; von Beeren, Christoph; Blüthgen, Nico; Kronauer, Daniel J C

    2016-01-01

    Ant colonies provide well-protected and resource-rich environments for a plethora of symbionts. Historically, most studies of ants and their symbionts have had a narrow taxonomic scope, often focusing on a single ant or symbiont species. Here we discuss the prospects of studying these assemblies in a community ecology context using the framework of ecological network analysis. We introduce three basic network metrics that we consider particularly relevant for improving our knowledge of ant-symbiont communities: interaction specificity, network modularity, and phylogenetic signal. We then discuss army ant symbionts as examples of large and primarily parasitic communities, and symbiotic sternorrhynchans as examples of generally smaller and primarily mutualistic communities in the context of these network analyses. We argue that this approach will provide new and complementary insights into the evolutionary and ecological dynamics between ants and their many associates, and will facilitate comparisons across different ant-symbiont assemblages as well as across different types of ecological networks.

  12. Phylogenetic analysis of symbionts in feather-feeding lice of the genus Columbicola: evidence for repeated symbiont replacements

    OpenAIRE

    Smith, Wendy A.; Oakeson, Kelly F.; Johnson, Kevin P.; Reed, David L.; Carter, Tamar; Smith, Kari L; Koga, Ryuichi; Fukatsu, Takema; Dale H Clayton; Dale, Colin

    2013-01-01

    Background Many groups of insects have obligate bacterial symbionts that are vertically transmitted. Such associations are typically characterized by the presence of a monophyletic group of bacteria living in a well-defined host clade. In addition the phylogeny of the symbiotic bacteria is typically congruent with that of the host, signifying co-speciation. Here we show that bacteria living in a single genus of feather lice, Columbicola (Insecta: Phthiraptera), present an exception to this ty...

  13. Antitumor polyketide biosynthesis by an uncultivated bacterial symbiont of the marine sponge Theonella swinhoei

    OpenAIRE

    Piel, Jörn; Hui, Dequan; Wen, Gaiping; Butzke, Daniel; Platzer, Matthias; Fusetani, Nobuhiro; Matsunaga, Shigeki

    2004-01-01

    Bacterial symbionts have long been suspected to be the true producers of many drug candidates isolated from marine invertebrates. Sponges, the most important marine source of biologically active natural products, have been frequently hypothesized to contain compounds of bacterial origin. This symbiont hypothesis, however, remained unproven because of a general inability to cultivate the suspected producers. However, we have recently identified an uncultured Pseudomonas sp. symbiont as the mos...

  14. Co-Speciation of Earthworms and their nephridial symbionts, Acidovorax Spp

    DEFF Research Database (Denmark)

    Lund, Marie Braad; Fritz, Michael; Holmstrup, Martin

    2006-01-01

    in Denmark and DNA was extracted from their nephridia. Earthworm phylogeny was resolved on the basis of mitochondrial cytochrome c oxidase subunit I (COI) by direct PCR amplification and sequencing from the nephridial DNA extract. Symbiont 16S rRNA gene sequences were retrieved by cloning and sequencing...... the extracted DNA. The presence of the symbionts in the ampulla was verified by performing fluorescence in situ hybridization (FISH) on all worm species using an Acidovorax-specific probe. Earthworm and symbiont phylogeny was largely congruent, indicating that host and symbiont have indeed co-evolved since...

  15. Horizontally mounted solar collector

    Science.gov (United States)

    Black, D. H. (Inventor)

    1979-01-01

    Solar energy is collected by using a vertical deflector assembly, a stationary reflector and a horizontally mounted solar collector. The deflector assembly contains a plurality of vanes which change the direction of the solar energy to the vertical, while constantly keeping the same side of the deflector facing the sun. The vertical rays are then reflected off the stationary reflector and are then absorbed by the collector.

  16. Wide distribution range of rhizobial symbionts associated with pantropical sea-dispersed legumes.

    Science.gov (United States)

    Bamba, Masaru; Nakata, Sayuri; Aoki, Seishiro; Takayama, Koji; Núñez-Farfán, Juan; Ito, Motomi; Miya, Masaki; Kajita, Tadashi

    2016-12-01

    To understand the geographic distributions of rhizobia that associated with widely distributed wild legumes, 66 nodules obtained from 41 individuals including three sea-dispersed legumes (Vigna marina, Vigna luteola, and Canavalia rosea) distributed across the tropical and subtropical coastal regions of the world were studied. Partial sequences of 16S rRNA and nodC genes extracted from the nodules showed that only Bradyrhizobium and Sinorhizobium were associated with the pantropical legumes, and some of the symbiont strains were widely distributed over the Pacific. Horizontal gene transfer of nodulation genes were observed within the Bradyrhizobium and Sinorhizobium lineages. BLAST searches in GenBank also identified records of these strains from various legumes across the world, including crop species. However, one of the rhizobial strains was not found in GenBank, which implies the strain may have adapted to the littoral environment. Our results suggested that some rhizobia, which associate with the widespread sea-dispersed legume, distribute across a broad geographic range. By establishing symbiotic relationships with widely distributed rhizobia, the pantropical legumes may also be able to extend their range much further than other legume species.

  17. Phylogeny of nodulation and nitrogen-fixation genes in Bradyrhizobium: supporting evidence for the theory of monophyletic origin, and spread and maintenance by both horizontal and vertical transfer.

    Science.gov (United States)

    Menna, Pâmela; Hungria, Mariangela

    2011-12-01

    /housekeeping genes, in addition to shorter nodY/K sequences and the absence of nodZ, highlights a co-evolution process. Additionally, in a group of B. japonicum strains that were symbionts of soybean, vertical transfer seemed to represent the main genetic event. In conclusion, clustering of nodA and nifH gives additional support to the theory of monophyletic origin of the symbiotic genes in Bradyrhizobium and, in addition to the analysis of nodY/K and nodZ, indicates spread and maintenance of nod and nif genes through both vertical and horizontal transmission, apparently with the dominance of one or other of these events in some groups of strains.

  18. Horizontal drilling activity in Manitoba

    Energy Technology Data Exchange (ETDEWEB)

    Fox, J.

    1997-04-01

    An update of horizontal well drilling in Manitoba was provided. Manitoba`s productive formations are: (1) the Bakken Formation, (2) the Lodgepole Formation, (3) the Mission Canyon Formation, (4) the Amaranth Formation, and (5) the Melita Formation. A total of 28 exploratory wells and 29 development wells, including 11 horizontal wells were drilled in 1996. The 11 horizontal wells accounted for 30 per cent of the drilling meterage. The leading drillers for horizontal wells in Manitoba are Tundra Oil and Gas, Chevron, Anderson and HCO. Production from horizontal wells in 1996 totaled 310 cubic meter per day. To date, no horizontal wells have been drilled in the Bakken Formation. The least successful horizontal well application has been in the Lodgepole Formation. A summary of horizontal well production was provided for each Formation. 4 tabs., 10 figs.

  19. Environmental Factors Shape the Community of Symbionts in the Hoopoe Uropygial Gland More than Genetic Factors

    OpenAIRE

    Ruiz-Rodríguez, Magdalena; Soler, Juan J.; Martín-Vivaldi, Manuel; Martín-Platero, Antonio M.; Méndez, María; Peralta-Sánchez, Juan M.; Ananou, Samir; Valdivia, Eva; Martínez-Bueno, Manuel

    2014-01-01

    Exploring processes of coevolution of microorganisms and their hosts is a new imperative for life sciences. If bacteria protect hosts against pathogens, mechanisms facilitating the intergenerational transmission of such bacteria will be strongly selected by evolution. By disentangling the diversity of bacterial strains from the uropygium of hoopoes (Upupa epops) due to genetic relatedness or to a common environment, we explored the importance of horizontal (from the environment) and vertical ...

  20. Identification of Paenibacillus as a Symbiont in Acanthamoeba.

    Science.gov (United States)

    Maschio, Vinicius José; Corção, Gertrudes; Bücker, Francielle; Caumo, Karin; Rott, Marilise Brittes

    2015-09-01

    Amoebae of the genus Acanthamoeba occur worldwide and in addition to being pathogens, are important vehicles for microorganisms with clinical and environmental importance. This study aimed to evaluate the profiling of endosymbionts in 12 isolates of Acanthamoeba using V3 region of 16S rDNA denaturing gradient gel electrophoresis (DGGE) and sequencing. The DGGE enabled us to characterize the endosymbionts diversity in isolates of Acanthamoeba, and to identify Paenibacillus sp., an emerging pathogen, as an amoebic endosymbiont. The results of this study demonstrated that Acanthamoeba is capable of transporting a large number of endosymbionts. This is the first study that reports, the presence of Paenibacillus sp. as amebic symbiont.

  1. Genomic changes associated with the evolutionary transition of an insect gut symbiont into a blood-borne pathogen.

    Science.gov (United States)

    Segers, Francisca Hid; Kešnerová, Lucie; Kosoy, Michael; Engel, Philipp

    2017-05-01

    The genus Bartonella comprises facultative intracellular bacteria with a unique lifestyle. After transmission by blood-sucking arthropods they colonize the erythrocytes of mammalian hosts causing acute and chronic infectious diseases. Although the pathogen-host interaction is well understood, little is known about the evolutionary origin of the infection strategy manifested by Bartonella species. Here we analyzed six genomes of Bartonella apis, a honey bee gut symbiont that to date represents the closest relative of pathogenic Bartonella species. Comparative genomics revealed that B. apis encodes a large set of vertically inherited genes for amino acid and cofactor biosynthesis and nitrogen metabolism. Most pathogenic bartonellae have lost these ancestral functions, but acquired specific virulence factors and expanded a vertically inherited gene family for harvesting cofactors from the blood. However, the deeply rooted pathogen Bartonella tamiae has retained many of the ancestral genome characteristics reflecting an evolutionary intermediate state toward a host-restricted intraerythrocytic lifestyle. Our findings suggest that the ancestor of the pathogen Bartonella was a gut symbiont of insects and that the adaptation to blood-feeding insects facilitated colonization of the mammalian bloodstream. This study highlights the importance of comparative genomics among pathogens and non-pathogenic relatives to understand disease emergence within an evolutionary-ecological framework.

  2. A phase-variable surface layer from the gut symbiont bacteroides thetaiotaomicron

    OpenAIRE

    Fischbach, Michael; Taketani, M; Donia, MS; Jacobson, AN; Lambris, JD; Fischbach, MA

    2015-01-01

    © 2015 Taketani et al.The capsule from Bacteroides, a common gut symbiont, has long been a model system for studying the molecular mechanisms of host-symbiont interactions. The Bacteroides capsule is thought to consist of an array of phase-variable polysac

  3. Excess algal symbionts increase the susceptibility of reef corals to bleaching

    Science.gov (United States)

    Cunning, Ross; Baker, Andrew C.

    2013-03-01

    Rising ocean temperatures associated with global climate change are causing mass coral bleaching and mortality worldwide. Understanding the genetic and environmental factors that mitigate coral bleaching susceptibility may aid local management efforts to help coral reefs survive climate change. Although bleaching susceptibility depends partly on the genetic identity of a coral's algal symbionts, the effect of symbiont density, and the factors controlling it, remain poorly understood. By applying a new metric of symbiont density to study the coral Pocillopora damicornis during seasonal warming and acute bleaching, we show that symbiont cell ratio density is a function of both symbiont type and environmental conditions, and that corals with high densities are more susceptible to bleaching. Higher vulnerability of corals with more symbionts establishes a quantitative mechanistic link between symbiont density and the molecular basis for coral bleaching, and indicates that high densities do not buffer corals from thermal stress, as has been previously suggested. These results indicate that environmental conditions that increase symbiont densities, such as nutrient pollution, will exacerbate climate-change-induced coral bleaching, providing a mechanistic explanation for why local management to reduce these stressors will help coral reefs survive future warming.

  4. The role of symbiont genetic distance and potential adaptability in host preference towards Pseudonocardia symbionts in Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Thomas-Poulsen, Michael; Maynard, Janielle; Roland, Damien L.;

    2011-01-01

    ), help defend the ants’ fungal mutualist from specialized parasites. In Acromyrmex Mayr (Hymenoptera: Formicidae) leaf-cutting ants, individual colonies maintain either a single or a few strains of Pseudonocardia, and the symbiont is primarily vertically transmitted between generations by colony...... to the role of adaptive recognition, potential ecological flexibility in symbiont preference, and more broadly, in relation to self versus non-self recognition....

  5. Coral ontogeny affects early symbiont acquisition in laboratory-reared recruits

    Science.gov (United States)

    McIlroy, Shelby E.; Coffroth, Mary Alice

    2017-09-01

    In most coral species, the critical association with a subset of genetically diverse algal endosymbionts, Symbiodinium, is re-established anew each generation in early coral ontogeny. Yet little is known about the window during which these associations are established or the potential for altering symbiont associations through early exposure to non-native, and/or ecologically beneficial (e.g., stress tolerant), symbiont strains. This study examined the ontogenetic window of symbiont uptake in a restoration target species. Orbicella faveolata recruits, maintained aposymbiotic in laboratory tanks for 4 months, showed a significant decrease in symbiont acquisition upon exposure to natural seawater. Recruits initially inoculated with cultured Symbiodinium readily acquired additional strains from environmental symbiont populations upon exposure, but exogenous uptake also decreased in frequency after 4 months of laboratory rearing. Early exposure to Symbiodinium may benefit laboratory-reared recruits (e.g., enhance growth), but the potential for establishing long-term novel symbiotic associations may be limited.

  6. An Entomopathogenic Nematode Extends Its Niche by Associating with Different Symbionts.

    Science.gov (United States)

    Maher, Abigail M D; Asaiyah, Mohamed A M; Brophy, Caroline; Griffin, Christine T

    2017-01-01

    Bacterial symbionts are increasingly recognised as mediators of ecologically important traits of their animal hosts, with acquisition of new traits possible by uptake of novel symbionts. The entomopathogenic nematode Heterorhabditis downesi associates with two bacterial symbionts, Photorhabdus temperata subsp. temperata and P. temperata subsp. cinerea. At one intensively studied coastal dune site, P. temperata subsp. cinerea is consistently more frequently isolated than P. temperata subsp. temperata in H. downesi recovered from under the bare sand/Ammophila arrenaria of the front dunes (where harsh conditions, including drought, prevail). This is not the case in the more permissive closed dune grassland further from the sea. No differences were detected in ITS1 (internal transcribed spacer) sequence between nematode lines carrying either of the two symbiont subspecies, nor did they differ in their ability to utilise insects from three orders. The two symbionts could be readily swapped between lines, and both were carried in equal numbers within infective juveniles. In laboratory experiments, we tested whether the symbionts differentially affected nematode survival in insect cadavers that were allowed to dry. We assessed numbers of nematode infective juveniles emerging from insects that had been infected with H. downesi carrying either symbiont subspecies and then allowed to desiccate for up to 62 days. In moist conditions, cadavers produced similar numbers of nematodes, irrespective of the symbiont subspecies present, while under desiccating conditions, P. temperata subsp. cinerea cadavers yielded more nematode progeny than P. temperata subsp. temperata cadavers. Desiccating cadavers with the same nematode isolates, carrying either one or the other symbiont subspecies, confirmed that the symbiont was responsible for differences in nematode survival. Moreover, cadavers harbouring P. temperata subsp. cinerea had a reduced rate of drying relative to cadavers

  7. Genetic transformation and phylogeny of bacterial symbionts from tsetse.

    Science.gov (United States)

    Beard, C B; O'Neill, S L; Mason, P; Mandelco, L; Woese, C R; Tesh, R B; Richards, F F; Aksoy, S

    1993-01-01

    Two isolates of bacterial endosymbionts, GP01 and GM02, were established in cell free medium from haemolymph of the tsetse, Glossina pallidipes and G. morsitans. These microorganisms appear similar to rickettsia-like organisms reported previously from various tsetse species. The 16S rRNA sequence analysis, however, placed them within the gamma subdivision of the Proteobacteria, phylogenetically distinct from most members of the Rickettsiaceae which align with the alpha subdivision. Distinct multiple endogenous plasmids are harboured by GP01 and GM02, suggesting that the two isolates are different. Restriction mapping analysis showed that one of the conserved plasmids is present in high copy number and is at least 80 kb in size. A heterologous plasmid pSUP204, which contains the broad host range oriV replication origin, was used to transfect bacterial cultures. The symbiont GM02 was transformed, and it expressed plasmid encoded resistance to the antibiotics ampicillin, tetracycline and chloramphenicol. Transformation of these symbionts may provide a novel means for expressing anti-parasitic genes within tsetse populations.

  8. Well Spacing for Horizontal Wells

    Directory of Open Access Journals (Sweden)

    C.D.S. Keuengoua

    2011-06-01

    Full Text Available In the developing phase of a hydrocarbon reservoir and planning for drilling the production wells, it is necessary to drill the wells in an appropriate spacing to achieve maximum economic revenues during the reservoir life span. Well spacing which is the real location and interrelationship between producing oil or gas wells in an oil field is an important parameter. It is determined for the maximum ultimate production of a given reservoir and should be taken in consideration during well planning to avoid drilling of unnecessary wells. This study presents the concept of drainage area on horizontal well and horizontal productivity indices with different equations and their applications. A user friendly Excel Spreadsheet program was developed to calculate the productivity values of horizontal wells using three major available productivity equations. Also, the developed spreadsheet program was used to evaluate the effect of well spacing on the productivities of horizontal wells using productivity index approach and drainage area concept. It also helps to review the comparison between vertical and horizontal wells spacing based on drainage area concept. This program was validated, and then was used to study the effect of horizontal well length on the ratio of horizontal well productivity to vertical well productivity. The results show that higher ratio of horizontal well productivity to vertical well productivity values are obtained with increase length of the horizontal well. It is a very useful tool for making decision about the application of well spacing for horizontal wells.

  9. Oriented cluster perforating technology and its application in horizontal wells

    Directory of Open Access Journals (Sweden)

    Huabin Chen

    2016-11-01

    Full Text Available An oriented cluster perforating technology, which integrates both advantages of cluster and oriented perforating, will help solve a series of technical complexities in horizontal well drilling. For realizing its better application in oil and gas development, a series of technologies were developed including perforator self-weight eccentricity, matching of the electronic selective module codes with the surface program control, axial centralized contact signal transmission, and post-perforation intercluster sealing insulation. In this way, the following functions could be realized, such as cable-transmission horizontal well perforator self-weight orientation, dynamic signal transmission, reliable addressing & selective perforation and post-perforation intercluster sealing. The combined perforation and bridge plug or the multi-cluster perforation can be fulfilled in one trip of perforation string. As a result, the horizontal-well oriented cluster perforating technology based on cable conveying was developed. This technology was successfully applied in unconventional gas reservoir exploitation, such as shale gas and coalbed methane, with accurate orientation, reliable selective perforation and satisfactory inter-cluster sealing. The horizontal-well oriented cluster perforating technology benefits the orientation of horizontal well drilling with a definite target and direction, which provides a powerful support for the subsequent reservoir stimulation. It also promotes the fracturing fluid to sweep the principal pay zones to the maximum extent. Moreover, it is conductive to the formation of complex fracture networks in the reservoirs, making quality and efficient development of unconventional gas reservoirs possible.

  10. PRODUCTIVITY OF FRACTURED HORIZONTAL WELLS

    Directory of Open Access Journals (Sweden)

    Stjepan Antolović

    2009-12-01

    Full Text Available The interest and performance of horizontal drilling and completions has increased during the last two decades. Horizontal wells are advantageous compared to vertical wells in thin reservoirs, reservoirs with favorable vertical permeability and reservoirs with water and gas coning problems. In many reservoirs, the ratio of horizontal permeability to the vertical permeability is substantially larger than one and often is close to 10. Thus, these reservoirs are very good candidates for hydraulic fracturing. By hydraulic fracturing one or more fractures are created, which can be longitudinal or orthogonal. By that, flow is altered and it mostly conducts horizontally through reservoir toward horizontal wellbore. With this altered flow, fluid is produced faster, with less pressure loss by fluid unit of produced fluid. Some of the existing mathematical models to determine the productivity of multifractured horizontal wells are presented in this work (the paper is published in Croatian.

  11. Mutualism and asexual reproduction influence recognition genes in a fungal symbiont.

    Science.gov (United States)

    van der Nest, Magriet A; Steenkamp, Emma T; Wilken, Markus P; Stenlid, Jan; Wingfield, Mike J; Wingfield, Brenda D; Slippers, Bernard

    2013-06-01

    Mutualism between microbes and insects is common and alignment of the reproductive interests of microbial symbionts with this lifestyle typically involves clonal reproduction and vertical transmission by insect partners. Here the Amylostereum fungus-Sirex woodwasp mutualism was used to consider whether their prolonged association and predominance of asexuality have affected the mating system of the fungal partner. Nucleotide information for the pheromone receptor gene rab1, as well as the translation elongation factor 1α gene and ribosomal RNA internal transcribed spacer region were utilized. The identification of rab1 alleles in Amylostereum chailletii and Amylostereum areolatum populations revealed that this gene is more polymorphic than the other two regions, although the diversity of all three regions was lower than what has been observed in free-living Agaricomycetes. Our data suggest that suppressed recombination might be implicated in the diversification of rab1, while no evidence of balancing selection was detected. We also detected positive selection at only two codons, suggesting that purifying selection is important for the evolution of rab1. The symbiotic relationship with their insect partners has therefore influenced the diversity of this gene and influenced the manner in which selection drives and maintains this diversity in A. areolatum and A. chailletii.

  12. Identification of Methanotrophic Biomarker Lipids in the Symbiont-Containing Gills of Seep Mussels

    Science.gov (United States)

    Jahnke, L. L.; Zahiralis, K. D.; Klein, H. P.; Morrison, David (Technical Monitor)

    1994-01-01

    Mussels collected from hydrocarbon seeps in the Gulf of Mexico grow with methane as sole carbon and energy source due to a symbiotic association with methane-oxidizing bacteria. Transmission electron micrographs of mussel gills show cells with stacked intracytoplasmic membranes similar to type I methanotrophic bacteria. Methanotrophs are known to synthesize several types of cyclic triterpenes, hopanoids and methyl sterols, as well as unique monounsaturated fatty acid, double bond positional isomers that serve as biomarkers for this group. Lipid analysis of dissected mussels demonstrated the presence of these biomarkers predominantly in the gill tissue with much smaller amounts in mantle and remaining body tissues. Gill tissue contained 1150 micrograms/g dry wt. of hopanepolyol derivatives and diplopterol while the mantle tissue contained only 17 micrograms/g. The C16 monounsaturated fatty acids (16:1) characteristic of type I methanotrophic membranes dominated the gill tissue making up 53% of the total while only 5% 16:1 was present in the mantle tissue. The methyl sterol distribution was more dispersed. The predominant sterol in all tissues was cholesterol with lesser amounts of other desmethyl and 4-methyl sterols. The gill and mantle tissues contained 3461 micrograms (17% methyl) and 2750 micrograms (5% methyl) sterol per gm dry wt., respectively. Methyl sterol accounted for 44% of the sterol esters isolated from the gill, suggesting active demethylation of the methanotrophic sterols in this tissue. The use of lipid biomarkers could provide an effective means for identifying host-symbiont relationships.

  13. Gammaproteobacteria as essential primary symbionts in the striped shield bug, Graphosoma Lineatum (Hemiptera: Pentatomidae)

    Science.gov (United States)

    Karamipour, Naeime; Mehrabadi, Mohammad; Fathipour, Yaghoub

    2016-01-01

    Many members of suborder Heteroptra harbor heritable symbiotic bacteria. Here we characterize the gut symbiotic bacterium in Graphosoma lineatum (Hemiptera: Pentatomidae) by using molecular phylogeny, real-time PCR analysis as well as light and electron microscopy observations. The microscopy observations revealed the presence of a large number of rod-shaped bacterial cells in the crypts. A very high prevalence (98 to 100%) of the symbiont infection was found in the insect populations that strongly supports an intimate association between these two organisms. Real-time PCR analysis also showed that the Gammaproteobacteria dominated the crypts. The sequences of 16sr RNA and groEL genes of symbiont showed high levels of similarity (93 to 95%) to Pantoea agglomeranse and Erwinia herbicola Gammaproteobacteria. Phylogenetic analyses placed G. lineatum symbiont in a well-defined branch, divergent from other stink bug bacterial symbionts. Co-evolutionary analysis showed lack of host-symbiont phylogenetic congruence. Surface sterilization of eggs resulted in increased pre-adult stage in the offspring (aposymbionts) in comparison to the normal. Also, fecundity, longevity, and adult stage were significantly decreased in the aposymbionts. Therefore, it seems that the symbiont might play a vital function in the host biology, in which host optimal development depends on the symbiont. PMID:27609055

  14. Spectral Reflectance of Palauan Reef-Building Coral with Different Symbionts in Response to Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Brandon J. Russell

    2016-02-01

    Full Text Available Spectral reflectance patterns of corals are driven largely by the pigments of photosynthetic symbionts within the host cnidarian. The warm inshore bays and cooler offshore reefs of Palau share a variety of coral species with differing endosymbiotic dinoflagellates (genus: Symbiodinium, with the thermally tolerant Symbiodinium trenchii (S. trenchii (= type D1a or D1-4 predominating under the elevated temperature regimes inshore, and primarily Clade C types in the cooler reefs offshore. Spectral reflectance of two species of stony coral, Cyphastrea serailia (C. serailia and Pachyseris rugosa (P. rugosa, from both inshore and offshore locations shared multiple features both between sites and to similar global data from other studies. No clear reflectance features were evident which might serve as markers of thermally tolerant S. trenchii symbionts compared to the same species of coral with different symbionts. Reflectance from C. serailia colonies from inshore had a fluorescence peak at approximately 500 nm which was absent from offshore animals. Integrated reflectance across visible wavelengths had an inverse correlation to symbiont cell density and could be used as a relative indicator of the symbiont abundance for each type of coral. As hypothesized, coral colonies from offshore with Clade C symbionts showed a greater response to experimental heating, manifested as decreased symbiont density and increased reflectance or “bleaching” than their inshore counterparts with S. trenchii. Although no unique spectral features were found to distinguish species of symbiont, spectral differences related to the abundance of symbionts could prove useful in field and remote sensing studies.

  15. Biomineralization of magnet nanoparticles with bacterial symbionts of man

    Directory of Open Access Journals (Sweden)

    Horobets S.V.

    2014-06-01

    Full Text Available Bioinformational analysis of human’s bacterial symbionts (BS to study the process of biomineralization of biogenic magnetic nanoparticles (BMN was conducted. For this purpose in this paper a comparative analysis of amino acid sequences of proteins of magnetosome island of magnetotactic bacteria (MI MTB with human BS proteins using the program "BLAST-online" was made. A number of human BS may be potential producers of magnetic nanoparticles as evidenced by the experimental work of other authors. Considering obtained results it was shown that the interaction between tumor cells and some strains of human’s BS may occur due to the forces of magnetic dipole interaction, occuring between the endogenous magnetic nanoparticles of tumor cells and endogenous magnetosensitive particles of bacteria.

  16. Genomic diversification of giant enteric symbionts reflects host dietary lifestyles

    KAUST Repository

    Ngugi, David

    2017-08-24

    Herbivorous surgeonfishes are an ecologically successful group of reef fish that rely on marine algae as their principal food source. Here, we elucidated the significance of giant enteric symbionts colonizing these fishes regarding their roles in the digestive processes of hosts feeding predominantly on polysiphonous red algae and brown Turbinaria algae, which contain different polysaccharide constituents. Using metagenomics, single-cell genomics, and metatranscriptomic analyses, we provide evidence of metabolic diversification of enteric microbiota involved in the degradation of algal biomass in these fishes. The enteric microbiota is also phylogenetically and functionally simple relative to the complex lignocellulose-degrading microbiota of terrestrial herbivores. Over 90% of the enzymes for deconstructing algal polysaccharides emanate from members of a single bacterial lineage,

  17. Construction of a Metagenomic DNA Library of Sponge Symbionts and Screening of Antibacterial Metabolites

    Institute of Scientific and Technical Information of China (English)

    CHEN Juan; ZHU Tianjiao; LI Dehai; CUI Chengbin; FANG Yuchun; LIU Hongbing; LIU Peipei; GU Qianqun; ZHU Weiming

    2006-01-01

    To study the bioactive metabolites produced by sponge-derived uncultured symbionts, a metagenomic DNA library of the symbionts of sponge Gelliodes gracilis was constructed. The average size of DNA inserts in the library was 20 kb. This library was screened for antibiotic activity using paper disc assaying. Two clones displayed the antibacterial activity against Micrococcus tetragenus. The metabolites of these two clones were analyzed through HPLC. The result showed that their metabolites were quite different from those of the host E. coli DH5α and the host containing vector pHZ132. This study may present a new approach to exploring bioactive metabolites of sponge symbionts.

  18. Characteristics of HgCdTe epilayer grown by LPE using horizontal slider

    Indian Academy of Sciences (India)

    J K Radhakrishnan; S Sitharaman; S C Gupta

    2002-11-01

    The characteristics of HgCdTe epilayers grown in a modified horizontal slider system, are reported here. The surface morphology of the grown layers, their IR transmission characteristics, depth and lateral compositional uniformity, structural and electrical characteristics are discussed.

  19. Occurrence of Photobacterium leiognathi, as the bait organ symbiont in frogfish Antennarius hispidus

    Digital Repository Service at National Institute of Oceanography (India)

    Ramaiah, N.; Chandramohan, D.

    . Occurrence of P. leiognathi as the bait organ symbiont of A. hispidus is the first report. Being very strong mimics of their surrounding, frogfishes may couple the bacterial bioluminescence originating from their bait organs with that of their camouflaging...

  20. Patterns of interaction specificity of fungus-growing termites and Termitomyces symbionts in South Africa

    DEFF Research Database (Denmark)

    Aanen, Duur K; Ros, Vera I D; de Fine Licht, Henrik H

    2007-01-01

    BACKGROUND: Termites of the subfamily Macrotermitinae live in a mutualistic symbiosis with basidiomycete fungi of the genus Termitomyces. Here, we explored interaction specificity in fungus-growing termites using samples from 101 colonies in South-Africa and Senegal, belonging to eight species......: Analysis of Molecular Variance among symbiont ITS sequences across termite hosts at three hierarchical levels showed that 47 % of the variation occurred between genera, 18 % between species, and the remaining 35 % between colonies within species. Different patterns of specificity were evident. High mutual...... of divergent fungal symbionts. CONCLUSION: Interaction specificity was high at the genus level and generally much lower at the species level. A comparison of the observed diversity among fungal symbionts with the diversity among termite hosts, indicated that the fungal symbiont does not follow the general...

  1. Investigations on abundance and activity of microbial sponge symbionts using quantitative real - time PCR

    DEFF Research Database (Denmark)

    Kumala, Lars; Hentschel, Ute; Bayer, Kristina

    Marine sponges are hosts to dense and diverse microbial consortia that are likely to play a key role in the metabolic processes of the host sponge due to their enormous abundance. Common symbioses between nitrogen transforming microorganisms and sponges indicate complex nitrogen cycling within...... the host. Of particular interest is determining the community structure and function of microbial symbionts in order to gain deeper insight into host-symbiont interactions. We investigated the abundance and activity of microbial symbionts in two Mediterranean sponge species using quantitative real-time PCR....... An absolute quantification of functional genes and transcripts in archaeal and bacterial symbionts was conducted to determine their involvement in nitrification and denitrification, comparing the low microbial abundance (LMA) sponge Dysidea avara with the high microbial abundance (HMA) representative Aplysina...

  2. Temporal changes of symbiont density and host fitness after rifampicin treatment in a whitefly of the Bemisia tabaci species complex.

    Science.gov (United States)

    Shan, Hong-Wei; Zhang, Chang-Rong; Yan, Ting-Ting; Tang, Hai-Qin; Wang, Xiao-Wei; Liu, Shu-Sheng; Liu, Yin-Quan

    2016-04-01

    Microbial symbionts are essential or important partners to phloem-feeding insects. Antibiotics have been used to selectively eliminate symbionts from their host insects and establish host lines with or without certain symbionts for investigating functions of the symbionts. In this study, using the antibiotic rifampicin we attempted to selectively eliminate certain symbionts from a population of the Middle East-Asia Minor 1 whitefly of the Bemisia tabaci species complex, which harbors the primary symbiont "Candidatus Portiera aleyrodidarum" and two secondary symbionts "Candidatus Hamiltonella defensa" and Rickettsia. Neither the primary nor the secondary symbionts were completely depleted in the adults (F0) that fed for 48 h on a diet treated with rifampicin at concentrations of 1-100 μg/mL. However, both the primary and secondary symbionts were nearly completely depleted in the offspring (F1) of the rifampicin-treated adults. Although the F1 adults produced some eggs (F2), most of the eggs failed to hatch and none of them reached the second instar, and consequently the rifampicin-treated whitefly colony vanished at the F2 generation. Interestingly, quantitative polymerase chain reaction assays showed that in the rifampicin-treated whiteflies, the density of the primary symbiont was reduced at an obviously slower pace than the secondary symbionts. Mating experiments between rifampicin-treated and untreated adults demonstrated that the negative effects of rifampicin on host fitness were expressed when the females were treated by the antibiotic, and whether males were treated or not by the antibiotic had little contribution to the negative effects. These observations indicate that with this whitefly population it is not feasible to selectively eliminate the secondary symbionts using rifampicin without affecting the primary symbiont and establish host lines for experimental studies. However, the extinction of the whitefly colony at the second generation after

  3. The herbaceous landlord: integrating the effects of symbiont consortia within a single host.

    Science.gov (United States)

    Vandegrift, Roo; Roy, Bitty A; Pfeifer-Meister, Laurel; Johnson, Bart R; Bridgham, Scott D

    2015-01-01

    Plants are typically infected by a consortium of internal fungal associates, including endophytes in their leaves, as well as arbuscular mycorrhizal fungi (AMF) and dark septate endophytes (DSE) in their roots. It is logical that these organisms will interact with each other and the abiotic environment in addition to their host, but there has been little work to date examining the interactions of multiple symbionts within single plant hosts, or how the relationships among symbionts and their host change across environmental conditions. We examined the grass Agrostis capillaris in the context of a climate manipulation experiment in prairies in the Pacific Northwest, USA. Each plant was tested for presence of foliar endophytes in the genus Epichloë, and we measured percent root length colonized (PRLC) by AMF and DSE. We hypothesized that the symbionts in our system would be in competition for host resources, that the outcome of that competition could be driven by the benefit to the host, and that the host plants would be able to allocate carbon to the symbionts in such a way as to maximize fitness benefit within a particular environmental context. We found a correlation between DSE and AMF PRLC across climatic conditions; we also found a fitness cost to increasing DSE colonization, which was negated by presence of Epichloë endophytes. These results suggest that selective pressure on the host is likely to favor host/symbiont relationships that structure the community of symbionts in the most beneficial way possible for the host, not necessarily favoring the individual symbiont that is most beneficial to the host in isolation. These results highlight the need for a more integrative, systems approach to the study of host/symbiont consortia.

  4. Population genomics of a symbiont in the early stages of a pest invasion.

    Science.gov (United States)

    Brown, Amanda M V; Huynh, Lynn Y; Bolender, Caitlin M; Nelson, Kelly G; McCutcheon, John P

    2014-03-01

    Invasive species often depend on microbial symbionts, but few studies have examined the evolutionary dynamics of symbionts during the early stages of an invasion. The insect Megacopta cribraria and its bacterial nutritional symbiont Candidatus Ishikawaella capsulata invaded the southeastern US in 2009. While M. cribraria was initially discovered on wild kudzu plants, it was found as a pest on soybeans within 1 year of infestation. Because prior research suggests Ishikawaella confers the pest status--that is, the ability to thrive on soybeans--in some Megacopta species, we performed a genomic study on Ishikawaella from US. Megacopta cribraria populations to understand the role of the symbiont in driving host plant preferences. We included Ishikawaella samples collected in the first days of the invasion in 2009 and from 23 locations across the insect's 2011 US range. The 0.75 Mb symbiont genome revealed only 47 fixed differences from the pest-conferring Ishikawaella in Japan, with only one amino acid change in a nutrition-provisioning gene. This similarity, along with a lack of fixed substitutions in the US symbiont population, indicates that Ishikawella likely arrived in the US capable of being a soybean pest. Analyses of allele frequency changes between 2009 and 2011 uncover signatures of both positive and negative selection and suggest that symbionts on soybeans and kudzu experience differential selection for genes related to nutrient provisioning. Our data reveal the evolutionary trajectory of an important insect-bacteria symbiosis in the early stages of an invasion, highlighting the role microbial symbionts may play in the spread of invasive species.

  5. The herbaceous landlord: integrating the effects of symbiont consortia within a single host

    Directory of Open Access Journals (Sweden)

    Roo Vandegrift

    2015-11-01

    Full Text Available Plants are typically infected by a consortium of internal fungal associates, including endophytes in their leaves, as well as arbuscular mycorrhizal fungi (AMF and dark septate endophytes (DSE in their roots. It is logical that these organisms will interact with each other and the abiotic environment in addition to their host, but there has been little work to date examining the interactions of multiple symbionts within single plant hosts, or how the relationships among symbionts and their host change across environmental conditions. We examined the grass Agrostis capillaris in the context of a climate manipulation experiment in prairies in the Pacific Northwest, USA. Each plant was tested for presence of foliar endophytes in the genus Epichloë, and we measured percent root length colonized (PRLC by AMF and DSE. We hypothesized that the symbionts in our system would be in competition for host resources, that the outcome of that competition could be driven by the benefit to the host, and that the host plants would be able to allocate carbon to the symbionts in such a way as to maximize fitness benefit within a particular environmental context. We found a correlation between DSE and AMF PRLC across climatic conditions; we also found a fitness cost to increasing DSE colonization, which was negated by presence of Epichloë endophytes. These results suggest that selective pressure on the host is likely to favor host/symbiont relationships that structure the community of symbionts in the most beneficial way possible for the host, not necessarily favoring the individual symbiont that is most beneficial to the host in isolation. These results highlight the need for a more integrative, systems approach to the study of host/symbiont consortia.

  6. The symbiotic role of O-antigen of Burkholderia symbiont in association with host Riptortus pedestris.

    Science.gov (United States)

    Kim, Jiyeun Kate; Park, Ha Young; Lee, Bok Luel

    2016-07-01

    Riptortus pedestris harboring Burkholderia symbiont is a useful symbiosis model to study the molecular interactions between insects and bacteria. We recently reported that the lipopolysaccharide O-antigen is absent in the Burkholderia symbionts isolated from Riptortus guts. Here, we investigated the symbiotic role of O-antigen comprehensively in the Riptortus-Burkholderia model. Firstly, Burkholderia mutant strains deficient of O-antigen biosynthesis genes were generated and confirmed for their different patterns of the lipopolysaccharide by electrophoretic analysis. The O-antigen-deficient mutant strains initially exhibited a reduction of infectivity, having significantly lower level of symbiont population at the second-instar stage. However, both the wild-type and O-antigen mutant symbionts exhibited a similar level of symbiont population from the third-instar stage, indicating that the O-antigen deficiency did not affect the bacterial persistence in the host midgut. Taken together, we showed that the lipopolysaccharide O-antigen of gut symbiont plays an exclusive role in the initial symbiotic association.

  7. Convergent patterns in the evolution of mealybug symbioses involving different intrabacterial symbionts.

    Science.gov (United States)

    Szabó, Gitta; Schulz, Frederik; Toenshoff, Elena R; Volland, Jean-Marie; Finkel, Omri M; Belkin, Shimshon; Horn, Matthias

    2017-03-01

    Mealybugs (Insecta: Hemiptera: Pseudococcidae) maintain obligatory relationships with bacterial symbionts, which provide essential nutrients to their insect hosts. Most pseudococcinae mealybugs harbor a unique symbiosis setup with enlarged betaproteobacterial symbionts ('Candidatus Tremblaya princeps'), which themselves contain gammaproteobacterial symbionts. Here we investigated the symbiosis of the manna mealybug, Trabutina mannipara, using a metagenomic approach. Phylogenetic analyses revealed that the intrabacterial symbiont of T. mannipara represents a novel lineage within the Gammaproteobacteria, for which we propose the tentative name 'Candidatus Trabutinella endobia'. Combining our results with previous data available for the nested symbiosis of the citrus mealybug Planococcus citri, we show that synthesis of essential amino acids and vitamins and translation-related functions partition between the symbiotic partners in a highly similar manner in the two systems, despite the distinct evolutionary origin of the intrabacterial symbionts. Bacterial genes found in both mealybug genomes and complementing missing functions in both symbioses were likely integrated in ancestral mealybugs before T. mannipara and P. citri diversified. The high level of correspondence between the two mealybug systems and their highly intertwined metabolic pathways are unprecedented. Our work contributes to a better understanding of the only known intracellular symbiosis between two bacteria and suggests that the evolution of this unique symbiosis included the replacement of intrabacterial symbionts in ancestral mealybugs.

  8. Whitefly genome expression reveals host-symbiont interaction in amino acid biosynthesis.

    Science.gov (United States)

    Upadhyay, Santosh Kumar; Sharma, Shailesh; Singh, Harpal; Dixit, Sameer; Kumar, Jitesh; Verma, Praveen C; Chandrashekar, K

    2015-01-01

    Whitefly (Bemisia tabaci) complex is a serious insect pest of several crop plants worldwide. It comprises several morphologically indistinguishable species, however very little is known about their genetic divergence and biosynthetic pathways. In the present study, we performed transcriptome sequencing of Asia 1 species of B. tabaci complex and analyzed the interaction of host-symbiont genes in amino acid biosynthetic pathways. We obtained about 83 million reads using Illumina sequencing that assembled into 72716 unitigs. A total of 21129 unitigs were annotated at stringent parameters. Annotated unitigs were mapped to 52847 gene ontology (GO) terms and 131 Kyoto encyclopedia of genes and genomes (KEGG) pathways. Expression analysis of the genes involved in amino acid biosynthesis pathways revealed the complementation between whitefly and its symbiont partner Candidatus Portiera aleyrodidarum. Most of the non-essential amino acids and intermediates of essential amino acid pathways were supplied by the host insect to its symbiont. The symbiont expressed the pathways for the essential amino acids arginine, threonine and tryptophan and the immediate precursors of valine, leucine, isoleucine and phenyl-alanine. High level expression of the amino acid transporters in the whitefly suggested the molecular mechanisms for the exchange of amino acids between the host and the symbiont. Our study provides a comprehensive transcriptome data for Asia 1 species of B. tabaci complex that focusses light on integration of host and symbiont genes in amino acid biosynthesis pathways.

  9. Vitamin supplementation by gut symbionts ensures metabolic homeostasis in an insect host

    Science.gov (United States)

    Salem, Hassan; Bauer, Eugen; Strauss, Anja S.; Vogel, Heiko; Marz, Manja; Kaltenpoth, Martin

    2014-01-01

    Despite the demonstrated functional importance of gut microbes, our understanding of how animals regulate their metabolism in response to nutritionally beneficial symbionts remains limited. Here, we elucidate the functional importance of the African cotton stainer's (Dysdercus fasciatus) association with two actinobacterial gut symbionts and subsequently examine the insect's transcriptional response following symbiont elimination. In line with bioassays demonstrating the symbionts' contribution towards host fitness through the supplementation of B vitamins, comparative transcriptomic analyses of genes involved in import and processing of B vitamins revealed an upregulation of gene expression in aposymbiotic (symbiont-free) compared with symbiotic individuals; an expression pattern that is indicative of B vitamin deficiency in animals. Normal expression levels of these genes, however, can be restored by either artificial supplementation of B vitamins into the insect's diet or reinfection with the actinobacterial symbionts. Furthermore, the functional characterization of the differentially expressed thiamine transporter 2 through heterologous expression in Xenopus laevis oocytes confirms its role in cellular uptake of vitamin B1. These findings demonstrate that despite an extracellular localization, beneficial gut microbes can be integral to the host's metabolic homeostasis, reminiscent of bacteriome-localized intracellular mutualists. PMID:25339726

  10. Bacterial symbionts of the leafhopper Evacanthus interruptus (Linnaeus, 1758) (Insecta, Hemiptera, Cicadellidae: Evacanthinae).

    Science.gov (United States)

    Szklarzewicz, Teresa; Grzywacz, Beata; Szwedo, Jacek; Michalik, Anna

    2016-03-01

    Plant sap-feeding hemipterans harbor obligate symbiotic microorganisms which are responsible for the synthesis of amino acids missing in their diet. In this study, we characterized the obligate symbionts hosted in the body of the xylem-feeding leafhopper Evacanthus interruptus (Cicadellidae: Evacanthinae: Evacanthini) by means of histological, ultrastructural and molecular methods. We observed that E. interruptus is associated with two types of symbiotic microorganisms: bacterium 'Candidatus Sulcia muelleri' (Bacteroidetes) and betaproteobacterium that is closely related to symbionts which reside in two other Cicadellidae representatives: Pagaronia tredecimpunctata (Evacanthinae: Pagaronini) and Hylaius oregonensis (Bathysmatophorinae: Bathysmatophorini). Both symbionts are harbored in their own bacteriocytes which are localized between the body wall and ovaries. In E. interruptus, both Sulcia and betaproteobacterial symbionts are transovarially transmitted from one generation to the next. In the mature female, symbionts leave the bacteriocytes and gather around the posterior pole of the terminal oocytes. Then, they gradually pass through the cytoplasm of follicular cells surrounding the posterior pole of the oocyte and enter the space between them and the oocyte. The bacteria accumulate in the deep depression of the oolemma and form a characteristic 'symbiont ball'. In the light of the results obtained, the phylogenetic relationships within modern Cicadomorpha and some Cicadellidae subfamilies are discussed.

  11. Progress in the insect symbiont Rickettsia%昆虫共生细菌 Rickettsia 的研究进展

    Institute of Scientific and Technical Information of China (English)

    潘慧鹏; 张友军

    2012-01-01

    species. It can transmit vertically through eggs, and horizontally through parasitic wasps and host plants. It can influence the host reproduction by male-killing and parthenogenesis- It has beneficial or detrimental effects on its hosts and can increase the tolerance of its hosts to high temperature and parasitic wasps, and is correlated with its hosts ' susceptibility to insecticides, The insect symbiont Rickettsia has a reduced genome and might undergo considerable further reduction.

  12. Horizontal and Vertical Line Designs.

    Science.gov (United States)

    Johns, Pat

    2003-01-01

    Presents an art lesson in which students learn about the artist Piet Mondrian and create their own abstract artworks. Focuses on geometric shapes using horizontal and vertical lines. Includes background information about the artist. (CMK)

  13. Algal endosymbiosis in brown hydra: host/symbiont specificity.

    Science.gov (United States)

    Rahat, M; Reich, V

    1986-12-01

    Host/symbiont specificity has been investigated in non-symbiotic and aposymbiotic brown and green hydra infected with various free-living and symbiotic species and strains of Chlorella and Chlorococcum. Morphology and ultrastructure of the symbioses obtained have been compared. Aposymbiotic Swiss Hydra viridis and Japanese H. magnipapillata served as controls. In two strains of H. attenuata stable hereditary symbioses were obtained with Chlorococcum isolated from H. magnipapillata. In one strain of H. vulgaris, in H. oligactis and in aposymbiotic H. viridis chlorococci persisted for more than a week. Eight species of free-living Chlorococcum, 10 symbiotic and 10 free-living strains of Chlorella disappeared from the brown hydra within 1-2 days. In H. magnipapillata there was a graded distribution of chlorococci along the polyps. In hypostomal cells there were greater than 30 algae/cell while in endodermal cells of the mid-section or peduncle less than 10 algae/cell were found. In H. attenuata the algal distribution was irregular, there were up to five chlorocci/cell, and up to 20 cells/hydra hosted algae. In the dark most cells of Chlorococcum disappeared from H. magnipapillata and aposymbiotic hydra were obtained. Chlorococcum is thus an obligate phototroph, and host-dependent heterotrophy is not required for the preservation of a symbiosis. The few chlorococci that survived in the dark seem to belong to a less-demanding physiological strain. In variance with known Chlorella/H. viridis endosymbioses the chlorococci in H. magnipapillata and H. attenuata were tightly enveloped in the vacuolar membrane of the hosting cells with no visible perialgal space. Chlorococcum reproduced in these vacuoles and up to eight daughter cells were found within the same vacuole. We suggest that the graded or scant distribution of chlorococci in the various brown hydra, their inability to live in H. viridis and the inability of the various chlorellae to live in brown hydra are the

  14. Superresolution imaging captures carbohydrate utilization dynamics in human gut symbionts.

    Science.gov (United States)

    Karunatilaka, Krishanthi S; Cameron, Elizabeth A; Martens, Eric C; Koropatkin, Nicole M; Biteen, Julie S

    2014-11-11

    Gut microbes play a key role in human health and nutrition by catabolizing a wide variety of glycans via enzymatic activities that are not encoded in the human genome. The ability to recognize and process carbohydrates strongly influences the structure of the gut microbial community. While the effects of diet on the microbiota are well documented, little is known about the molecular processes driving metabolism. To provide mechanistic insight into carbohydrate catabolism in gut symbionts, we studied starch processing in real time in the model Bacteroides thetaiotaomicron starch utilization system (Sus) by single-molecule fluorescence. Although previous studies have explored Sus protein structure and function, the transient interactions, assembly, and collaboration of these outer membrane proteins have not yet been elucidated in live cells. Our live-cell superresolution imaging reveals that the polymeric starch substrate dynamically recruits Sus proteins, serving as an external scaffold for bacterial membrane assembly of the Sus complex, which may promote efficient capturing and degradation of starch. Furthermore, by simultaneously localizing multiple Sus outer membrane proteins on the B. thetaiotaomicron cell surface, we have characterized the dynamics and stoichiometry of starch-induced Sus complex assembly on the molecular scale. Finally, based on Sus protein knockout strains, we have discerned the mechanism of starch-induced Sus complex assembly in live anaerobic cells with nanometer-scale resolution. Our insights into the starch-induced outer membrane protein assembly central to this conserved nutrient uptake mechanism pave the way for the development of dietary or pharmaceutical therapies to control Bacteroidetes in the intestinal tract to enhance human health and treat disease. In this study, we used nanometer-scale superresolution imaging to reveal dynamic interactions between the proteins involved in starch processing by the prominent human gut symbiont

  15. Experimental investigation of horizontal convection

    OpenAIRE

    Muñoz Córdoba, Lucía

    2015-01-01

    Fluid circulation driven by buoyancy forces due to a thermal gradient on a horizontal boundary, known as horizontal convection, is experimentally studied. For that purpose, a methacrylate box with inner dimensions 300x150x150 mm3 (LxWxH) whose bottom is composed by a heat exchanger and a printed circuit board is lled with water. The heat exchanger provides a uniform temperature boundary condition while the printed circuit board provides a boundary condition of uniform heat ...

  16. The Arthromitus stage of Bacillus cereus: intestinal symbionts of animals

    Science.gov (United States)

    Margulis, L.; Jorgensen, J. Z.; Dolan, S.; Kolchinsky, R.; Rainey, F. A.; Lo, S. C.

    1998-01-01

    In the guts of more than 25 species of arthropods we observed filaments containing refractile inclusions previously discovered and named "Arthromitus" in 1849 by Joseph Leidy [Leidy, J. (1849) Proc. Acad. Nat. Sci. Philadelphia 4, 225-233]. We cultivated these microbes from boiled intestines of 10 different species of surface-cleaned soil insects and isopod crustaceans. Literature review and these observations lead us to conclude that Arthromitus are spore-forming, variably motile, cultivable bacilli. As long rod-shaped bacteria, they lose their flagella, attach by fibers or fuzz to the intestinal epithelium, grow filamentously, and sporulate from their distal ends. When these organisms are incubated in culture, their life history stages are accelerated by light and inhibited by anoxia. Characterization of new Arthromitus isolates from digestive tracts of common sow bugs (Porcellio scaber), roaches (Gromphodorhina portentosa, Blaberus giganteus) and termites (Cryptotermes brevis, Kalotermes flavicollis) identifies these flagellated, spore-forming symbionts as a Bacillus sp. Complete sequencing of the 16S rRNA gene from four isolates (two sow bug, one hissing roach, one death's head roach) confirms these as the low-G+C Gram-positive eubacterium Bacillus cereus. We suggest that B. cereus and its close relatives, easily isolated from soil and grown on nutrient agar, enjoy filamentous growth in moist nutrient-rich intestines of healthy arthropods and similar habitats.

  17. Marine sponges and their microbial symbionts: love and other relationships.

    Science.gov (United States)

    Webster, Nicole S; Taylor, Michael W

    2012-02-01

    Many marine sponges harbour dense and diverse microbial communities of considerable ecological and biotechnological importance. While the past decade has seen tremendous advances in our understanding of the phylogenetic diversity of sponge-associated microorganisms (more than 25 bacterial phyla have now been reported from sponges), it is only in the past 3-4 years that the in situ activity and function of these microbes has become a major research focus. Already the rewards of this new emphasis are evident, with genomics and experimental approaches yielding novel insights into symbiont function. Key steps in the nitrogen cycle [denitrification, anaerobic ammonium oxidation (Anammox)] have recently been demonstrated in sponges for the first time, with diverse bacteria - including the sponge-associated candidate phylum 'Poribacteria'- being implicated in these processes. In this minireview we examine recent major developments in the microbiology of sponges, and identify several research areas (e.g. biology of viruses in sponges, effects of environmental stress) that we believe are deserving of increased attention. © 2011 Society for Applied Microbiology and Blackwell Publishing Ltd.

  18. The Arthromitus stage of Bacillus cereus: intestinal symbionts of animals

    Science.gov (United States)

    Margulis, L.; Jorgensen, J. Z.; Dolan, S.; Kolchinsky, R.; Rainey, F. A.; Lo, S. C.

    1998-01-01

    In the guts of more than 25 species of arthropods we observed filaments containing refractile inclusions previously discovered and named "Arthromitus" in 1849 by Joseph Leidy [Leidy, J. (1849) Proc. Acad. Nat. Sci. Philadelphia 4, 225-233]. We cultivated these microbes from boiled intestines of 10 different species of surface-cleaned soil insects and isopod crustaceans. Literature review and these observations lead us to conclude that Arthromitus are spore-forming, variably motile, cultivable bacilli. As long rod-shaped bacteria, they lose their flagella, attach by fibers or fuzz to the intestinal epithelium, grow filamentously, and sporulate from their distal ends. When these organisms are incubated in culture, their life history stages are accelerated by light and inhibited by anoxia. Characterization of new Arthromitus isolates from digestive tracts of common sow bugs (Porcellio scaber), roaches (Gromphodorhina portentosa, Blaberus giganteus) and termites (Cryptotermes brevis, Kalotermes flavicollis) identifies these flagellated, spore-forming symbionts as a Bacillus sp. Complete sequencing of the 16S rRNA gene from four isolates (two sow bug, one hissing roach, one death's head roach) confirms these as the low-G+C Gram-positive eubacterium Bacillus cereus. We suggest that B. cereus and its close relatives, easily isolated from soil and grown on nutrient agar, enjoy filamentous growth in moist nutrient-rich intestines of healthy arthropods and similar habitats.

  19. Comparative Genomics of a Parthenogenesis-Inducing Wolbachia Symbiont

    Directory of Open Access Journals (Sweden)

    Amelia R. I. Lindsey

    2016-07-01

    Full Text Available Wolbachia is an intracellular symbiont of invertebrates responsible for inducing a wide variety of phenotypes in its host. These host-Wolbachia relationships span the continuum from reproductive parasitism to obligate mutualism, and provide a unique system to study genomic changes associated with the evolution of symbiosis. We present the genome sequence from a parthenogenesis-inducing Wolbachia strain (wTpre infecting the minute parasitoid wasp Trichogramma pretiosum. The wTpre genome is the most complete parthenogenesis-inducing Wolbachia genome available to date. We used comparative genomics across 16 Wolbachia strains, representing five supergroups, to identify a core Wolbachia genome of 496 sets of orthologous genes. Only 14 of these sets are unique to Wolbachia when compared to other bacteria from the Rickettsiales. We show that the B supergroup of Wolbachia, of which wTpre is a member, contains a significantly higher number of ankyrin repeat-containing genes than other supergroups. In the wTpre genome, there is evidence for truncation of the protein coding sequences in 20% of ORFs, mostly as a result of frameshift mutations. The wTpre strain represents a conversion from cytoplasmic incompatibility to a parthenogenesis-inducing lifestyle, and is required for reproduction in the Trichogramma host it infects. We hypothesize that the large number of coding frame truncations has accompanied the change in reproductive mode of the wTpre strain.

  20. Insect symbionts as hidden players in insect-plant interactions

    NARCIS (Netherlands)

    Frago, E.; Dicke, M.; Godfray, H.C.J.

    2012-01-01

    There is growing evidence of the importance of microbial mutualistic symbioses in insect-plant interactions. Mutualists may affect host plant range and enable insects to manipulate plant physiology for their own benefit. The plant can also be a route for the horizontal transfer of mutualistic microo

  1. Horizontal fiscal imbalance in Germany

    Directory of Open Access Journals (Sweden)

    Paweł Kowalik

    2015-04-01

    Full Text Available Regional inequalities are currently a challenge for the majority of the countries, in particular the large ones. The problem of public income redistribution emerges due to possible differentiation of the economic development level of territorial units. The most often considered problem is the vertical distribution. The horizontal division of income is far less frequently considered. Horizontal fiscal imbalance or regional tax inequalities seem to be graver than the vertical imbalance, particularly in developing countries. The public finance system, in particular in federations, is often very complex. Public finance of federations and federated states are not often based on the same assumptions. This leads to differences among regions, both vertical and horizontal. The use of the presented measures helps identify those differences and permits developing mechanisms equalising those inequalities. It should be remembered that those measures may have certain drawbacks, and they mainly focus on certain specific values of income redistribution. Thereby several measures should be applied in measurements and the obtained results should be compared. There are no up-to-date measurements and comparisons of horizontal fiscal imbalance among countries.. The aim of this paper is to measure horizontal fiscal imbalance in Germany, especially after reunification, which represents one of two models of federalism. At the beginning it shows the static and dynamic measurements presented in the literature that can be used to measure the horizontal fiscal imbalance. And then it is followed by the results of calculations for Germany in the period 1970-2013. As expected, horizontal imbalance was much lower before than after the reunification of Germany. After the reunification there were large disparities between "old" and "new" länder. This imbalance is gradually reduced. In comparison with the results obtained for the USA [Kowalik 2014, pp. 144-148] it can be said

  2. The role of symbiont genetic distance and potential adaptability in host preference towards Pseudonocardia symbionts in Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Thomas-Poulsen, Michael; Maynard, Janielle; Roland, Damien L.

    2011-01-01

    ), help defend the ants’ fungal mutualist from specialized parasites. In Acromyrmex Mayr (Hymenoptera: Formicidae) leaf-cutting ants, individual colonies maintain either a single or a few strains of Pseudonocardia, and the symbiont is primarily vertically transmitted between generations by colony...

  3. The geographical patterns of symbiont diversity in the invasive legume Mimosa pudica can be explained by the competitiveness of its symbionts and by the host genotype.

    Science.gov (United States)

    Melkonian, Rémy; Moulin, Lionel; Béna, Gilles; Tisseyre, Pierre; Chaintreuil, Clémence; Heulin, Karine; Rezkallah, Naïma; Klonowska, Agnieszka; Gonzalez, Sophie; Simon, Marcelo; Chen, Wen-Ming; James, Euan K; Laguerre, Gisèle

    2014-07-01

    Variations in the patterns of diversity of symbionts have been described worldwide on Mimosa pudica, a pan-tropical invasive species that interacts with both α and β-rhizobia. In this study, we investigated if symbiont competitiveness can explain these variations and the apparent prevalence of β- over α-rhizobia. We developed an indirect method to measure the proportion of nodulation against a GFP reference strain and tested its reproducibility and efficiency. We estimated the competitiveness of 54 strains belonging to four species of β-rhizobia and four of α-rhizobia, and the influence of the host genotype on their competitiveness. Our results were compared with biogeographical patterns of symbionts and host varieties. We found: (i) a strong strain effect on competitiveness largely explained by the rhizobial species, with Burkholderia phymatum being the most competitive species, followed by B. tuberum, whereas all other species shared similar and reduced levels of competitiveness; (ii) plant genotype can increase the competitiveness of Cupriavidus taiwanensis. The latter data support the likelihood of the strong adaptation of C. taiwanensis with the M. pudica var. unijuga and help explain its prevalence as a symbiont of this variety over Burkholderia species in some environments, most notably in Taiwan. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  4. Niche acclimatization in Red Sea corals is dependent on flexibility of host-symbiont association

    KAUST Repository

    Ziegler, Maren

    2015-08-06

    Knowledge of host-symbiont specificity and acclimatization capacity of corals is crucial for understanding implications of environmental change. Whilst some corals have been shown to associate with a number of symbionts that may comprise different physiologies, most corals associate with only one dominant Symbiodinium species at a time. Coral communities in the Red Sea thrive under large fluctuations of environmental conditions, but the degree and mechanisms of coral acclimatization are largely unexplored. Here we investigated the potential for niche acclimatization in 2 dominant corals from the central Red Sea, Pocillopora verrucosa and Porites lutea, in relation to the fidelity of the underlying coral-symbiont association. Repeated sampling over 2 seasons along a cross-shelf and depth gradient revealed a stable symbiont association in P. verrucosa and flexible association in P. lutea. A statistical biological-environmental matching routine revealed that the high plasticity of photophysiology and photopigments in the stable Symbiodinium microadriaticum (type A1) community in P. verrucosa were correlated with environmental influences along spatio-temporal dimensions. In contrast, photophysiology and pigments were less variable within each symbiont type from P. lutea indicating that niche acclimatization was rather regulated by a flexible association with a variable Symbiodinium community. Based on these data, we advocate an extended concept of phenotypic plasticity of the coral holobiont, in which the scleractinian host either associates with a specific Symbiodinium type with a broad physiological tolerance, or the host-symbiont pairing is more flexible to accommodate for different symbiont associations, each adapted to specific environmental settings.

  5. An invasive Mimosa in India does not adopt the symbionts of its native relatives.

    Science.gov (United States)

    Gehlot, Hukam Singh; Tak, Nisha; Kaushik, Muskan; Mitra, Shubhajit; Chen, Wen-Ming; Poweleit, Nicole; Panwar, Dheeren; Poonar, Neetu; Parihar, Rashmita; Tak, Alkesh; Sankhla, Indu Singh; Ojha, Archana; Rao, Satyawada Rama; Simon, Marcelo F; Reis Junior, Fabio Bueno Dos; Perigolo, Natalia; Tripathi, Anil K; Sprent, Janet I; Young, J Peter W; James, Euan K; Gyaneshwar, Prasad

    2013-07-01

    The large monophyletic genus Mimosa comprises approx. 500 species, most of which are native to the New World, with Central Brazil being the main centre of radiation. All Brazilian Mimosa spp. so far examined are nodulated by rhizobia in the betaproteobacterial genus Burkholderia. Approximately 10 Mya, transoceanic dispersal resulted in the Indian subcontinent hosting up to six endemic Mimosa spp. The nodulation ability and rhizobial symbionts of two of these, M. hamata and M. himalayana, both from north-west India, are here examined, and compared with those of M. pudica, an invasive species. Nodules were collected from several locations, and examined by light and electron microscopy. Rhizobia isolated from them were characterized in terms of their abilities to nodulate the three Mimosa hosts. The molecular phylogenetic relationships of the rhizobia were determined by analysis of 16S rRNA, nifH and nodA gene sequences. Both native Indian Mimosa spp. nodulated effectively in their respective rhizosphere soils. Based on 16S rRNA, nifH and nodA sequences, their symbionts were identified as belonging to the alphaproteobacterial genus Ensifer, and were closest to the 'Old World' Ensifer saheli, E. kostiensis and E. arboris. In contrast, the invasive M. pudica was predominantly nodulated by Betaproteobacteria in the genera Cupriavidus and Burkholderia. All rhizobial strains tested effectively nodulated their original hosts, but the symbionts of the native species could not nodulate M. pudica. The native Mimosa spp. in India are not nodulated by the Burkholderia symbionts of their South American relatives, but by a unique group of alpha-rhizobial microsymbionts that are closely related to the 'local' Old World Ensifer symbionts of other mimosoid legumes in north-west India. They appear not to share symbionts with the invasive M. pudica, symbionts of which are mostly beta-rhizobial.

  6. Transient hypermutagenesis accelerates the evolution of legume endosymbionts following horizontal gene transfer.

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    Philippe Remigi

    2014-09-01

    Full Text Available Horizontal gene transfer (HGT is an important mode of adaptation and diversification of prokaryotes and eukaryotes and a major event underlying the emergence of bacterial pathogens and mutualists. Yet it remains unclear how complex phenotypic traits such as the ability to fix nitrogen with legumes have successfully spread over large phylogenetic distances. Here we show, using experimental evolution coupled with whole genome sequencing, that co-transfer of imuABC error-prone DNA polymerase genes with key symbiotic genes accelerates the evolution of a soil bacterium into a legume symbiont. Following introduction of the symbiotic plasmid of Cupriavidus taiwanensis, the Mimosa symbiont, into pathogenic Ralstonia solanacearum we challenged transconjugants to become Mimosa symbionts through serial plant-bacteria co-cultures. We demonstrate that a mutagenesis imuABC cassette encoded on the C. taiwanensis symbiotic plasmid triggered a transient hypermutability stage in R. solanacearum transconjugants that occurred before the cells entered the plant. The generated burst in genetic diversity accelerated symbiotic adaptation of the recipient genome under plant selection pressure, presumably by improving the exploration of the fitness landscape. Finally, we show that plasmid imuABC cassettes are over-represented in rhizobial lineages harboring symbiotic plasmids. Our findings shed light on a mechanism that may have facilitated the dissemination of symbiotic competency among α- and β-proteobacteria in natura and provide evidence for the positive role of environment-induced mutagenesis in the acquisition of a complex lifestyle trait. We speculate that co-transfer of complex phenotypic traits with mutagenesis determinants might frequently enhance the ecological success of HGT.

  7. DRILL BITS FOR HORIZONTAL WELLS

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    Paolo Macini

    1996-12-01

    Full Text Available This paper underlines the importance of the correct drill bit application in horizontal wells. Afler the analysis of the peculiarities of horizontal wells and drainholes drilling techniques, advantages and disadvantages of the application of both roller cone and fixed cutters drill bits have been discussed. Also, a review of the potential specific featuries useful for a correct drill bit selection in horizontal small diameter holes has been highlighted. Drill bits for these special applications, whose importance is quickly increasing nowadays, should be characterised by a design capable to deliver a good penetration rate low WOB, and, at the same time, be able to withstand high RPM without premature cutting structure failure and undergauge. Formation properties will also determine the cutting structure type and the eventual specific features for additional gauge and shoulder protection.

  8. Bacterial symbionts: prospects for the sustainable production of invertebrate-derived pharmaceuticals.

    Science.gov (United States)

    Piel, J

    2006-01-01

    Invertebrate animals, such as sponges, tunicates and bryozoans, are among the most important sources of biomedically relevant natural products. However, as these animals generally contain only low quantities of the compounds, further pharmacological development is in most cases difficult. There is increasing evidence that many metabolites, in particular polyketides and nonribosomally synthesized peptides, are not produced by the animals themselves but by associated bacterial symbionts. This symbiont hypothesis currently attracts considerable interest, since it implicates that animal-independent production systems based on bacterial fermentation processes could be created. This review gives an overview about recent developments in the research on natural product symbiosis. Different techniques will be discussed that have been employed to pinpoint the actual producer. Since bacterial symbionts are highly fastidious and have been generally resistant to cultivation attempts, emphasis will be laid on culture-independent strategies, such as cell separation approaches and the cloning of biosynthetic genes. These strategies have provided insights into possible sources of several natural products, e.g. the bryostatins, pederin, the onnamides, swinholide A and theopalauamide. Finally, potential techniques for the generation of renewable supplies of symbiont-derived drug candidates will be discussed. Cultivation approaches and the heterologous expression of cloned biosynthesis genes from uncultured symbionts could in future provide access to several important marine drug candidates, including bryostatin 1, halichondrin or ET-743.

  9. Differential responses of the coral host and their algal symbiont to thermal stress.

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    William Leggat

    Full Text Available The success of any symbiosis under stress conditions is dependent upon the responses of both partners to that stress. The coral symbiosis is particularly susceptible to small increases of temperature above the long term summer maxima, which leads to the phenomenon known as coral bleaching, where the intracellular dinoflagellate symbionts are expelled. Here we for the first time used quantitative PCR to simultaneously examine the gene expression response of orthologs of the coral Acropora aspera and their dinoflagellate symbiont Symbiodinium. During an experimental bleaching event significant up-regulation of genes involved in stress response (HSP90 and HSP70 and carbon metabolism (glyceraldehyde-3-phosphate dehydrogenase, α-ketoglutarate dehydrogenase, glycogen synthase and glycogen phosphorylase from the coral host were observed. In contrast in the symbiont, HSP90 expression decreased, while HSP70 levels were increased on only one day, and only the α-ketoglutarate dehydrogenase expression levels were found to increase. In addition the changes seen in expression patterns of the coral host were much larger, up to 10.5 fold, compared to the symbiont response, which in all cases was less than 2-fold. This targeted study of the expression of key metabolic and stress genes demonstrates that the response of the coral and their symbiont vary significantly, also a response in the host transcriptome was observed prior to what has previously been thought to be the temperatures at which thermal stress events occur.

  10. Recognition- and defense-related gene expression at 3 resynthesis stages in lichen symbionts.

    Science.gov (United States)

    Athukorala, Sarangi N P; Piercey-Normore, Michele D

    2015-01-01

    Recognition and defense responses are early events in plant-pathogen interactions and between lichen symbionts. The effect of elicitors on responses between lichen symbionts is not well understood. The objective of this study was to compare the difference in recognition- and defense-related gene expression as a result of culture extracts (containing secreted water-soluble elicitors) from compatible and incompatible interactions at each of 3 resynthesis stages in the symbionts of Cladonia rangiferina. This study investigated gene expression by quantitative PCR in cultures of C. rangiferina and its algal partner, Asterochloris glomerata/irregularis, after incubation with liquid extracts from cultures of compatible and incompatible interactions at 3 early resynthesis stages. Recognition-related genes were significantly upregulated only after physical contact, demonstrating symbiont recognition in later resynthesis stages than expected. One of 3 defense-related genes, chit, showed significant downregulation in early resynthesis stages and upregulation in the third resynthesis stage, demonstrating a need for the absence of chitinase early in thallus formation and a need for its presence in later stages as an algal defense reaction. This study revealed that recognition- and defense-related genes are triggered by components in culture extracts at 3 stages of resynthesis, and some defense-related genes may be induced throughout thallus growth. The parasitic nature of the interaction shows parallels between lichen symbionts and plant pathogenic systems.

  11. Parallel metatranscriptome analyses of host and symbiont gene expression in the gut of the termite Reticulitermes flavipes

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    Zhou Xuguo

    2009-10-01

    Full Text Available Abstract Background Termite lignocellulose digestion is achieved through a collaboration of host plus prokaryotic and eukaryotic symbionts. In the present work, we took a combined host and symbiont metatranscriptomic approach for investigating the digestive contributions of host and symbiont in the lower termite Reticulitermes flavipes. Our approach consisted of parallel high-throughput sequencing from (i a host gut cDNA library and (ii a hindgut symbiont cDNA library. Subsequently, we undertook functional analyses of newly identified phenoloxidases with potential importance as pretreatment enzymes in industrial lignocellulose processing. Results Over 10,000 expressed sequence tags (ESTs were sequenced from the 2 libraries that aligned into 6,555 putative transcripts, including 171 putative lignocellulase genes. Sequence analyses provided insights in two areas. First, a non-overlapping complement of host and symbiont (prokaryotic plus protist glycohydrolase gene families known to participate in cellulose, hemicellulose, alpha carbohydrate, and chitin degradation were identified. Of these, cellulases are contributed by host plus symbiont genomes, whereas hemicellulases are contributed exclusively by symbiont genomes. Second, a diverse complement of previously unknown genes that encode proteins with homology to lignase, antioxidant, and detoxification enzymes were identified exclusively from the host library (laccase, catalase, peroxidase, superoxide dismutase, carboxylesterase, cytochrome P450. Subsequently, functional analyses of phenoloxidase activity provided results that were strongly consistent with patterns of laccase gene expression. In particular, phenoloxidase activity and laccase gene expression are mostly restricted to symbiont-free foregut plus salivary gland tissues, and phenoloxidase activity is inducible by lignin feeding. Conclusion To our knowledge, this is the first time that a dual host-symbiont transcriptome sequencing effort

  12. Insect symbiotic bacteria harbour viral pathogens for transovarial transmission.

    Science.gov (United States)

    Jia, Dongsheng; Mao, Qianzhuo; Chen, Yong; Liu, Yuyan; Chen, Qian; Wu, Wei; Zhang, Xiaofeng; Chen, Hongyan; Li, Yi; Wei, Taiyun

    2017-03-06

    Many insects, including mosquitoes, planthoppers, aphids and leafhoppers, are the hosts of bacterial symbionts and the vectors for transmitting viral pathogens(1-3). In general, symbiotic bacteria can indirectly affect viral transmission by enhancing immunity and resistance to viruses in insects(3-5). Whether symbiotic bacteria can directly interact with the virus and mediate its transmission has been unknown. Here, we show that an insect symbiotic bacterium directly harbours a viral pathogen and mediates its transovarial transmission to offspring. We observe rice dwarf virus (a plant reovirus) binding to the envelopes of the bacterium Sulcia, a common obligate symbiont of leafhoppers(6-8), allowing the virus to exploit the ancient oocyte entry path of Sulcia in rice leafhopper vectors. Such virus-bacterium binding is mediated by the specific interaction of the viral capsid protein and the Sulcia outer membrane protein. Treatment with antibiotics or antibodies against Sulcia outer membrane protein interferes with this interaction and strongly prevents viral transmission to insect offspring. This newly discovered virus-bacterium interaction represents the first evidence that a viral pathogen can directly exploit a symbiotic bacterium for its transmission. We believe that such a model of virus-bacterium communication is a common phenomenon in nature.

  13. Plant nodulation inducers enhance horizontal gene transfer of Azorhizobium caulinodans symbiosis island.

    Science.gov (United States)

    Ling, Jun; Wang, Hui; Wu, Ping; Li, Tao; Tang, Yu; Naseer, Nawar; Zheng, Huiming; Masson-Boivin, Catherine; Zhong, Zengtao; Zhu, Jun

    2016-11-29

    Horizontal gene transfer (HGT) of genomic islands is a driving force of bacterial evolution. Many pathogens and symbionts use this mechanism to spread mobile genetic elements that carry genes important for interaction with their eukaryotic hosts. However, the role of the host in this process remains unclear. Here, we show that plant compounds inducing the nodulation process in the rhizobium-legume mutualistic symbiosis also enhance the transfer of symbiosis islands. We demonstrate that the symbiosis island of the Sesbania rostrata symbiont, Azorhizobium caulinodans, is an 87.6-kb integrative and conjugative element (ICE(Ac)) that is able to excise, form a circular DNA, and conjugatively transfer to a specific site of gly-tRNA gene of other rhizobial genera, expanding their host range. The HGT frequency was significantly increased in the rhizosphere. An ICE(Ac)-located LysR-family transcriptional regulatory protein AhaR triggered the HGT process in response to plant flavonoids that induce the expression of nodulation genes through another LysR-type protein, NodD. Our study suggests that rhizobia may sense rhizosphere environments and transfer their symbiosis gene contents to other genera of rhizobia, thereby broadening rhizobial host-range specificity.

  14. Horizontal Diplopia Following Upper Blepharoplasty

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    Tomás Ortiz-Basso

    2014-09-01

    Full Text Available Diplopia is an infrequent complication after blepharoplasty. Most of the cases are in its vertical form due to trauma of the extraocular muscles. In this article, we present a case of horizontal diplopia following cosmetic upper blepharoplasty; we review the literature on this unexpected complication and offer some recommendations to avoid it.

  15. Initial Symbiont Contact Orchestrates Host Organ-wide Transcriptional Changes that Prime Tissue Colonization

    Science.gov (United States)

    Kremer, Natacha; Philipp, Eva E.R.; Carpentier, Marie-Christine; Brennan, Caitlin A.; Kraemer, Lars; Altura, Melissa A.; Augustin, René; Häsler, Robert; Heath-Heckman, Elizabeth A. C.; Peyer, Suzanne M.; Schwartzman, Julia; Rader, Bethany; Ruby, Edward G.; Rosenstiel, Philip; McFall-Ngai, Margaret J.

    2013-01-01

    SUMMARY Upon transit to colonization sites, bacteria often experience critical priming that prepares them for subsequent, specific interactions with the host; however, the underlying mechanisms are poorly described. During initiation of the symbiosis between the bacterium Vibrio fischeri and its squid host, which can be observed directly and in real time, ~5 V. fischeri cells aggregate along the mucociliary membranes of a superficial epithelium prior to entering host tissues. Here we show that these few early host-associated symbionts specifically induce robust changes in host gene expression that are critical to subsequent colonization steps. This exquisitely sensitive response to its specific symbiotic partner includes the upregulation of a host endochitinase, whose activity hydrolyzes polymeric chitin in the mucus into chitobiose, thereby priming the symbiont and also producing a chemoattractant gradient that promotes V. fischeri migration into host tissues. Thus, the host responds transcriptionally upon initial symbiont contact, which facilitates subsequent colonization. PMID:23954157

  16. Gut symbiont enhances insecticide resistance in a significant pest, the oriental fruit fly Bactrocera dorsalis (Hendel).

    Science.gov (United States)

    Cheng, Daifeng; Guo, Zijun; Riegler, Markus; Xi, Zhiyong; Liang, Guangwen; Xu, Yijuan

    2017-02-01

    Symbiotic bacteria affect insect physiology and ecology. They may also mediate insecticide resistance within their hosts and thereby impact pest and vector control practices. Here, we document a novel mechanism of insecticide resistance in which a gut symbiont of the tephritid pest fruit fly Bactrocera dorsalis enhances resistance to the organophosphate insecticide trichlorphon. We demonstrated that the gut symbiont Citrobacter sp. (CF-BD) plays a key role in the degradation of trichlorphon. Based on a comparative genomics analysis with other Citrobacter species, phosphatase hydrolase genes were identified in CF-BD. These CF-BD genes had higher expression when trichlorphon was present. Bactrocera dorsalis inoculated with isolated CF-BD obtained higher trichlorphon resistance, while antibiotic-treated flies were less resistant confirming the key role of CF-BD in insecticide resistance. Our findings suggest that symbiont-mediated insecticide resistance can readily develop in B. dorsalis and may represent a more widely relevant insecticide resistance mechanism than previously recognized.

  17. Mixed infections may promote diversification of mutualistic symbionts: why are there ineffective rhizobia?

    Science.gov (United States)

    Friesen, M L; Mathias, A

    2010-02-01

    While strategy variation is a key feature of symbiotic mutualisms, little work focuses on the origin of this diversity. Rhizobia strategies range from mutualistic nitrogen fixers to parasitic nonfixers that hoard plant resources to increase their own survival in soil. Host plants reward beneficial rhizobia with higher nodule growth rates, generating a trade-off between reproduction in nodules and subsequent survival in soil. However, hosts might not discriminate between strains in mixed infections, allowing nonfixing strains to escape sanctions. We construct an adaptive dynamics model of symbiotic nitrogen-fixation and find general situations where symbionts undergo adaptive diversification, but in most situations complete nonfixers do not evolve. Social conflict in mixed infections when symbionts face a survival-reproduction trade-off can drive the origin of some coexisting symbiont strategies, where less mutualistic strains exploit benefits generated by better mutualists.

  18. Preferential host switching and codivergence shaped radiation of bark beetle symbionts, nematodes of Micoletzkya (Nematoda: Diplogastridae).

    Science.gov (United States)

    Susoy, V; Herrmann, M

    2014-05-01

    Host-symbiont systems are of particular interest to evolutionary biology because they allow testable inferences of diversification processes while also providing both a historical basis and an ecological context for studies of adaptation. Our investigations of bark beetle symbionts, predatory nematodes of the genus Micoletzkya, have revealed remarkable diversity of the group along with a high level of host specificity. Cophylogenetic analyses suggest that evolution of the nematodes was largely influenced by the evolutionary history of beetles. The diversification of the symbionts, however, could not be attributed to parallel divergence alone; our results indicate that adaptive radiation of the nematodes was shaped by preferential host shifts among closely related beetles along with codivergence. Whereas ecological and geographic isolation have played a major role in the diversification of Micoletzkya at shallow phylogenetic depths, adaptations towards related hosts have played a role in shaping cophylogenetic structure at a larger evolutionary scale.

  19. Cophylogenetics and biogeography reveal a coevolved relationship between sloths and their symbiont algae.

    Science.gov (United States)

    Fountain, Emily D; Pauli, Jonathan N; Mendoza, Jorge E; Carlson, Jenna; Peery, M Zachariah

    2017-05-01

    Specialized species, like arboreal folivores, often develop beneficial relationships with symbionts to exploit ecologically constrained lifestyles. Although coevolution can drive speciation by specialization of a symbiont to a host, a symbiotic relationship is not indicative of coevolution between host and symbiont. We tested for coevolved relationships between highly specialized two- and three-toed sloths (Choloepus spp. and Bradypus spp., respectively) and their symbiotic algae using cophylogenies and phylogeography. Our phylogeographic analysis showed a biogeographic pattern for the sloth distribution that was not found in the algal phylogeny. We found support for congruence between the sloth and algae phylogenies, implying cospeciation, only in the Bradypus lineage. Algae host-switching occurred from Bradypus spp. to Choloepus spp. Our results support a previously hypothesized symbiotic relationship between sloths and the algae in their fur and indicate that coevolution may have played a role in algae diversification. More broadly, convergent evolution may facilitate host switching between deeply diverged host lineages.

  20. Genomic deletions disrupt nitrogen metabolism pathways of a cyanobacterial diatom symbiont

    Science.gov (United States)

    Hilton, Jason A.; Foster, Rachel A.; James Tripp, H.; Carter, Brandon J.; Zehr, Jonathan P.; Villareal, Tracy A.

    2013-01-01

    Diatoms with symbiotic N2-fixing cyanobacteria are often abundant in the oligotrophic open ocean gyres. The most abundant cyanobacterial symbionts form heterocysts (specialized cells for N2 fixation) and provide nitrogen (N) to their hosts, but their morphology, cellular locations and abundances differ depending on the host. Here we show that the location of the symbiont and its dependency on the host are linked to the evolution of the symbiont genome. The genome of Richelia (found inside the siliceous frustule of Hemiaulus) is reduced and lacks ammonium transporters, nitrate/nitrite reductases and glutamine:2-oxoglutarate aminotransferase. In contrast, the genome of the closely related Calothrix (found outside the frustule of Chaetoceros) is more similar to those of free-living heterocyst-forming cyanobacteria. The genome of Richelia is an example of metabolic streamlining that has implications for the evolution of N2-fixing symbiosis and potentially for manipulating plant–cyanobacterial interactions. PMID:23612308

  1. Investigating the causes and consequences of symbiont shuffling in a multi-partner reef coral symbiosis under environmental change.

    Science.gov (United States)

    Cunning, R; Silverstein, R N; Baker, A C

    2015-06-22

    Dynamic symbioses may critically mediate impacts of climate change on diverse organisms, with repercussions for ecosystem persistence in some cases. On coral reefs, increases in heat-tolerant symbionts after thermal bleaching can reduce coral susceptibility to future stress. However, the relevance of this adaptive response is equivocal owing to conflicting reports of symbiont stability and change. We help reconcile this conflict by showing that change in symbiont community composition (symbiont shuffling) in Orbicella faveolata depends on the disturbance severity and recovery environment. The proportion of heat-tolerant symbionts dramatically increased following severe experimental bleaching, especially in a warmer recovery environment, but tended to decrease if bleaching was less severe. These patterns can be explained by variation in symbiont performance in the changing microenvironments created by differentially bleached host tissues. Furthermore, higher proportions of heat-tolerant symbionts linearly increased bleaching resistance but reduced photochemical efficiency, suggesting that any change in community structure oppositely impacts performance and stress tolerance. Therefore, even minor symbiont shuffling can adaptively benefit corals, although fitness effects of resulting trade-offs are difficult to predict. This work helps elucidate causes and consequences of dynamism in symbiosis, which is critical to predicting responses of multi-partner symbioses such as O. faveolata to environmental change. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

  2. Fickle or Faithful: The Roles of Host and Environmental Context in Determining Symbiont Composition in Two Bathymodioline Mussels.

    Directory of Open Access Journals (Sweden)

    Sven R Laming

    Full Text Available The Mediterranean Sea and adjoining East Atlantic Ocean host a diverse array of small-sized mussels that predominantly live on sunken, decomposing organic remains. At least two of these, Idas modiolaeformis and Idas simpsoni, are known to engage in gill-associated symbioses; however, the composition, diversity and variability of these symbioses with changing habitat and location is poorly defined. The current study presents bacterial symbiont assemblage data, derived from 454 pyrosequencing carried out on replicate specimens of these two host species, collected across seven sample sites found in three oceanographic regions in the Mediterranean and East Atlantic. The presence of several bacterial OTUs in both the Mediterranean Sea and eastern Atlantic suggests that similar symbiont candidates occur on both sides of the Strait of Gibraltar. The results reveal markedly different symbiotic modes in the two species. Idas modiolaeformis displays high symbiont diversity and flexibility, with strong variation in symbiont composition from the East Mediterranean to the East Atlantic. Idas simpsoni displays low symbiont diversity but high symbiont fidelity, with a single dominant OTU occurring in all specimens analysed. These differences are argued to be a function of the host species, where subtle differences in host evolution, life-history and behaviour could partially explain the observed patterns. The variability in symbiont compositions, particularly in Idas modiolaeformis, is thought to be a function of the nature, context and location of the habitat from which symbiont candidates are sourced.

  3. Bacteriome-localized intracellular symbionts in pollen-feeding beetles of the genus Dasytes (Coleoptera, Dasytidae

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    Benjamin Weiss

    2016-09-01

    Full Text Available Several insect taxa are associated with intracellular symbionts that provision limiting nutrients to their hosts. Such tightly integrated symbioses are especially common in insects feeding on nutritionally challenging diets like phloem sap or vertebrate blood, but also occur in seed-eating and omnivorous taxa. Here, we characterize an intracellular symbiosis in pollen-feeding beetles of the genus Dasytes (Coleoptera, Dasytidae. High-throughput tag-encoded 16S amplicon pyrosequencing of adult D. plumbeus and D. virens revealed a single gamma-proteobacterial symbiont that amounts to 52.4-98.7% of the adult beetles’ entire microbial community. Almost complete 16S rRNA sequences phylogenetically placed the symbiont into a clade comprising Buchnera and other insect endosymbionts, but sequence similarities to these closest relatives were surprisingly low (83.4 to 87.4%. Using histological examination, three-dimensional reconstructions, and fluorescence in situ hybridization, we localized the symbionts in three mulberry-shaped bacteriomes that are associated with the mid- to hind-gut transition in adult male and female beetles. Given the specialized pollen-feeding habits of the adults that contrasts with the larvae’s carnivorous lifestyle, the symbionts may provision limiting essential amino acids or vitamins as in other intracellular symbioses, or they might produce digestive enzymes that break up the fastidious pollen walls and thereby contribute to the host’s nutrition. In either case, the presence of gamma-proteobacterial symbionts in pollen-feeding beetles indicates that intracellular mutualists are more widely distributed across insects with diverse feeding habits than previously recognized.

  4. Aphid thermal tolerance is governed by a point mutation in bacterial symbionts.

    Directory of Open Access Journals (Sweden)

    Helen E Dunbar

    2007-05-01

    Full Text Available Symbiosis is a ubiquitous phenomenon generating biological complexity, affecting adaptation, and expanding ecological capabilities. However, symbionts, which can be subject to genetic limitations such as clonality and genomic degradation, also impose constraints on hosts. A model of obligate symbiosis is that between aphids and the bacterium Buchnera aphidicola, which supplies essential nutrients. We report a mutation in Buchnera of the aphid Acyrthosiphon pisum that recurs in laboratory lines and occurs in field populations. This single nucleotide deletion affects a homopolymeric run within the heat-shock transcriptional promoter for ibpA, encoding a small heat-shock protein. This Buchnera mutation virtually eliminates the transcriptional response of ibpA to heat stress and lowers its expression even at cool or moderate temperatures. Furthermore, this symbiont mutation dramatically affects host fitness in a manner dependent on thermal environment. Following a short heat exposure as juveniles, aphids bearing short-allele symbionts produced few or no progeny and contained almost no Buchnera, in contrast to aphids bearing symbionts without the deletion. Conversely, under constant cool conditions, aphids containing symbionts with the short allele reproduced earlier and maintained higher reproductive rates. The short allele has appreciable frequencies in field populations (up to 20%, further supporting the view that lowering of ibpA expression improves host fitness under some conditions. This recurring Buchnera mutation governs thermal tolerance of aphid hosts. Other cases in which symbiont microevolution has a major effect on host ecological tolerance are likely to be widespread because of the high mutation rates of symbiotic bacteria and their crucial roles in host metabolism and development.

  5. Biogeography and molecular diversity of coral symbionts in the genus Symbiodinium around the Arabian Peninsula

    KAUST Repository

    Ziegler, Maren

    2017-01-02

    Aim: Coral reefs rely on the symbiosis between scleractinian corals and intracellular, photosynthetic dinoflagellates of the genus Symbiodinium making the assessment of symbiont diversity critical to our understanding of ecological resilience of these ecosystems. This study characterizes Symbiodinium diversity around the Arabian Peninsula, which contains some of the most thermally diverse and understudied reefs on Earth. Location: Shallow water coral reefs throughout the Red Sea (RS), Sea of Oman (SO), and Persian/Arabian Gulf (PAG). Methods: Next-generation sequencing of the ITS2 marker gene was used to assess Symbiodinium community composition and diversity comprising 892 samples from 46 hard and soft coral genera. Results: Corals were associated with a large diversity of Symbiodinium, which usually consisted of one or two prevalent symbiont types and many types at low abundance. Symbiodinium communities were strongly structured according to geographical region and to a lesser extent by coral host identity. Overall symbiont communities were composed primarily of species from clade A and C in the RS, clade A, C, and D in the SO, and clade C and D in the PAG, representing a gradual shift from C- to D-dominated coral hosts. The analysis of symbiont diversity in an Operational Taxonomic Unit (OTU)-based framework allowed the identification of differences in symbiont taxon richness over geographical regions and host genera. Main conclusions: Our study represents a comprehensive overview over biogeography and molecular diversity of Symbiodinium in the Arabian Seas, where coral reefs thrive in one of the most extreme environmental settings on the planet. As such our data will serve as a baseline for further exploration into the effects of environmental change on host-symbiont pairings and the identification and ecological significance of Symbiodinium types from regions already experiencing \\'Future Ocean\\' conditions.

  6. Differential responses of the whitefly Bemisia tabaci symbionts to unfavorable low and high temperatures.

    Science.gov (United States)

    Shan, Hong-Wei; Lu, Yu-Heng; Bing, Xiao-Li; Liu, Shu-Sheng; Liu, Yin-Quan

    2014-10-01

    The whitefly Bemisia tabaci complex contains many cryptic species, of which the Middle East-Asia Minor 1 (MEAM1) and Mediterranean (MED) are notorious invasive pests. In our field-collected whitefly samples, MEAM1 harbors an obligate primary symbiont "Candidatus Portiera aleyrodidarum" and two secondary symbionts, "Candidatus Hamiltonella defensa" and Rickettsia sp., whereas MED has only "Ca. Portiera aleyrodidarum" and "Ca. Hamiltonella defensa." Both "Ca. Portiera aleyrodidarum" and "Ca. Hamiltonella defensa" are intracellular endosymbionts residing in the bacteriomes, whereas Rickettsia sp. has a scattered distribution throughout the host body cavity. We examined responses of these symbionts to adverse temperatures as well as survival of the host insects. After cold treatment at 5 or 10 °C or heat treatment at 35 or 40 °C for 24 h, respectively, the infection rates of all symbionts were not significantly decreased based on diagnosis PCR. However, quantitative PCR assays indicated significant reduction of "Ca. Hamiltonella defensa" at 40 °C, and the reduction became greater as the duration increased. Compared with "Ca. Hamiltonella defensa," "Ca. Portiera aleyrodidarum" was initially less affected in the first day but then showed more rapid reduction at days 3-5. The density of Rickettsia sp. fluctuated but was not reduced significantly at 40 °C. Meanwhile, the mortality rates of the host whiteflies elevated rapidly as the duration of exposure to heat treatment increased. The differential responses of various symbionts to adverse temperatures imply complex interactions among the symbionts inside the same host insect and highlight the importance of taking the whole bacterial community into account in studies of symbioses.

  7. Earthworms and their Nephridial Symbionts: Co-diversification and Maintenance of the Symbiosis

    DEFF Research Database (Denmark)

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

    Earthworms harbor in their nephridia (excretory organs) symbiotic bacteria which densely colonize a specific part of the nephridia, called the ampulla [1]. The symbiosis is species-specific and the symbionts form their own monophyletic genus Verminephrobacter (β-proteobacteria) [2...... showed no significant differences in growth rate and fecundity between symbiotic and aposymbiotic worms. Thus the symbionts do not appear to have an effect on worm fitness, under growth conditions tested. The underlying functional and maintaining mechanisms of this symbiosis remain a conundrum. [1] Knop...

  8. Advances in Marine Microbial Symbionts in the China Sea and Related Pharmaceutical Metabolites

    Directory of Open Access Journals (Sweden)

    Zhiyong Li

    2009-04-01

    Full Text Available Marine animals and plants such as sponges, sea squirts, corals, worms and algae host diverse and abundant symbiotic microorganisms. Marine microbial symbionts are possible the true producers or take part in the biosynthesis of some bioactive marine natural products isolated from the marine organism hosts. Investigation of the pharmaceutical metabolites may reveal the biosynthesis mechanisms of related natural products and solve the current problem of supply limitation in marine drug development. This paper reviews the advances in diversity revelation, biological activity and related pharmaceutical metabolites, and functional genes of marine microbial symbionts from the China Sea.

  9. Nitrogen transfer in the interface between the symbionts in pea root nodules

    DEFF Research Database (Denmark)

    Rosendahl, L.; Mouritzen, P.; Rudbeck, A.

    2001-01-01

    Transport mechanisms for transfer of nitrogen from the bacteroid side across the symbiosome membrane of pea (Pisum sativum L.) root nodules were identified by the use of energised bacteroid side-out symbiosome membrane vesicles. Such membrane vesicles were used to study a mechanism with high...... as ammonium. In the symbiosome subfraction, which represents the interface between the symbionts, specific aspartate aminotransferase activity was more than four times as high as in the bacteroid cytosol. This finding supports a hypothesis that transamination cycles operating between the symbionts may...

  10. Global diversity of marine isopods (except Asellota and crustacean symbionts.

    Directory of Open Access Journals (Sweden)

    Gary C B Poore

    Full Text Available The crustacean order Isopoda (excluding Asellota, crustacean symbionts and freshwater taxa comprise 3154 described marine species in 379 genera in 37 families according to the WoRMS catalogue. The history of taxonomic discovery over the last two centuries is reviewed. Although a well defined order with the Peracarida, their relationship to other orders is not yet resolved but systematics of the major subordinal taxa is relatively well understood. Isopods range in size from less than 1 mm to Bathynomus giganteus at 365 mm long. They inhabit all marine habitats down to 7280 m depth but with few doubtful exceptions species have restricted biogeographic and bathymetric ranges. Four feeding categories are recognised as much on the basis of anecdotal evidence as hard data: detritus feeders and browsers, carnivores, parasites, and filter feeders. Notable among these are the Cymothooidea that range from predators and scavengers to external blood-sucking micropredators and parasites. Isopods brood 10-1600 eggs depending on individual species. Strong sexual dimorphism is characteristic of several families, notably in Gnathiidae where sessile males live with a harem of females while juvenile praniza stages are ectoparasites of fish. Protandry is known in Cymothoidae and protogyny in Anthuroidea. Some Paranthuridae are neotenous. About half of all coastal, shelf and upper bathyal species have been recorded in the MEOW temperate realms, 40% in tropical regions and the remainder in polar seas. The greatest concentration of temperate species is in Australasia; more have been recorded from temperate North Pacific than the North Atlantic. Of tropical regions, the Central Indo-Pacific is home to more species any other region. Isopods are decidedly asymmetrical latitudinally with 1.35 times as many species in temperate Southern Hemisphere than the temperate North Atlantic and northern Pacific, and almost four times as many Antarctic as Arctic species. More species

  11. Global diversity of marine isopods (except Asellota and crustacean symbionts).

    Science.gov (United States)

    Poore, Gary C B; Bruce, Niel L

    2012-01-01

    The crustacean order Isopoda (excluding Asellota, crustacean symbionts and freshwater taxa) comprise 3154 described marine species in 379 genera in 37 families according to the WoRMS catalogue. The history of taxonomic discovery over the last two centuries is reviewed. Although a well defined order with the Peracarida, their relationship to other orders is not yet resolved but systematics of the major subordinal taxa is relatively well understood. Isopods range in size from less than 1 mm to Bathynomus giganteus at 365 mm long. They inhabit all marine habitats down to 7280 m depth but with few doubtful exceptions species have restricted biogeographic and bathymetric ranges. Four feeding categories are recognised as much on the basis of anecdotal evidence as hard data: detritus feeders and browsers, carnivores, parasites, and filter feeders. Notable among these are the Cymothooidea that range from predators and scavengers to external blood-sucking micropredators and parasites. Isopods brood 10-1600 eggs depending on individual species. Strong sexual dimorphism is characteristic of several families, notably in Gnathiidae where sessile males live with a harem of females while juvenile praniza stages are ectoparasites of fish. Protandry is known in Cymothoidae and protogyny in Anthuroidea. Some Paranthuridae are neotenous. About half of all coastal, shelf and upper bathyal species have been recorded in the MEOW temperate realms, 40% in tropical regions and the remainder in polar seas. The greatest concentration of temperate species is in Australasia; more have been recorded from temperate North Pacific than the North Atlantic. Of tropical regions, the Central Indo-Pacific is home to more species any other region. Isopods are decidedly asymmetrical latitudinally with 1.35 times as many species in temperate Southern Hemisphere than the temperate North Atlantic and northern Pacific, and almost four times as many Antarctic as Arctic species. More species are known from the

  12. Cytogenetic and symbiont analysis of five members of the B. dorsalis complex (Diptera, Tephritidae): no evidence of chromosomal or symbiont-based speciation events.

    Science.gov (United States)

    Augustinos, Antonios A; Drosopoulou, Elena; Gariou-Papalexiou, Aggeliki; Asimakis, Elias D; Cáceres, Carlos; Tsiamis, George; Bourtzis, Kostas; Penelope Mavragani-Tsipidou; Zacharopoulou, Antigone

    2015-01-01

    The Bactrocera dorsalis species complex, currently comprising about 90 entities has received much attention. During the last decades, considerable effort has been devoted to delimiting the species of the complex. This information is of great importance for agriculture and world trade, since the complex harbours several pest species of major economic importance and other species that could evolve into global threats. Speciation in Diptera is usually accompanied by chromosomal rearrangements, particularly inversions that are assumed to reduce/eliminate gene flow. Other candidates currently receiving much attention regarding their possible involvement in speciation are reproductive symbionts, such as Wolbachia, Spiroplasma, Arsenophonus, Rickettsia and Cardinium. Such symbionts tend to spread quickly through natural populations and can cause a variety of phenotypes that promote pre-mating and/or post-mating isolation and, in addition, can affect the biology, physiology, ecology and evolution of their insect hosts in various ways. Considering all these aspects, we present: (a) a summary of the recently gained knowledge on the cytogenetics of five members of the Bactrocera dorsalis complex, namely Bactrocera dorsalis s.s., Bactrocera invadens, Bactrocera philippinensis, Bactrocera papayae and Bactrocera carambolae, supplemented by additional data from a Bactrocera dorsalis s.s. colony from China, as well as by a cytogenetic comparison between the dorsalis complex and the genetically close species, Bactrocera tryoni, and, (b) a reproductive symbiont screening of 18 different colonized populations of these five taxa. Our analysis did not reveal any chromosomal rearrangements that could differentiate among them. Moreover, screening for reproductive symbionts was negative for all colonies derived from different geographic origins and/or hosts. There are many different factors that can lead to speciation, and our data do not support chromosomal and/or symbiotic

  13. The Role of Symbiont Genetic Distance and Potential Adaptability in Host Preference Towards Pseudonocardia Symbionts in Acromyrmex Leaf-Cutting Ants

    OpenAIRE

    Thomas-Poulsen, Michael; Maynard, Janielle; Roland, Damien L; Currie, Cameron R

    2011-01-01

    Fungus-growing ants display symbiont preference in behavioral assays, both towards the fungus they cultivate for food and Actinobacteria they maintain on their cuticle for antibiotic production against parasites. These Actinobacteria, genus Pseudonocardia Henssen (Pseudonocardiacea: Actinomycetales), help defend the ants’ fungal mutualist from specialized parasites. In Acromyrmex Mayr (Hymenoptera: Formicidae) leaf-cutting ants, individual colonies maintain either a single or a few strains of...

  14. Horizontally oriented plates in clouds

    CERN Document Server

    Bréon, François-Marie

    2011-01-01

    Horizontally oriented plates in clouds generate a sharp specular reflectance signal in the glint direction, often referred to as "subsun". This signal (amplitude and width) may be used to analyze the relative area fraction of oriented plates in the cloud top layer and their characteristic tilt angle to the horizontal. We make use of spaceborne measurements from the POLDER instrument to provide a statistical analysis of these parameters. More than half of the clouds show a detectable maximum reflectance in the glint direction, although this maximum may be rather faint. The typical effective fraction (area weighted) of oriented plates in clouds lies between 10-3 and 10-2. For those oriented plates, the characteristic tilt angle is less than 1 degree in most cases. These low fractions imply that the impact of oriented plates on the cloud albedo is insignificant. The largest proportion of clouds with horizontally oriented plates is found in the range 500-700 hPa, in agreement with typical in situ observation of p...

  15. Partial Horizontal Laryngectomy and Epiglottiplasty

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    In order to evaluate the availability of the lateral horizontal laryngectomy and anaplasty of epiglottis to treat somepatients with specific supraglottic carcinomas and hypopharyngeal carcinomas, 17 cases of laryngeal and hypopharyngeal carcinomas were retrospectively analyzed, whose tumors were located at the lateral margin of epiglottis, aryepiglottic fold, medial wall of piriformfossa and were treated by the lateral horizontal laryngectomy and anaplasty of epiglottis. The results showed that all cases took food by mouth in postoperative 9-14 days and subjected to decannulation in postoperative 9-15 days. Three cases had postoperative hoarse voice. The free-disease survival rate of 3 years was 71.4 % in 14 cases followed up after the first surgical therapy, and the overall free-disease survival rate of 3 years was 85.7 % after the second surgical therapy. It was concluded that the manipulations of the lateral horizontal laryngectomy and epiglottiplasty were simple. It could alleviate the postoperative symptoms of aspiration and bucking remarkably and shorten their postoperative recovery time, yet does not lower the survival rate of patients if laryngocarcinoma or hypopharyngeal carcinoma cases were properly selected.

  16. Transmission eigenvalues

    Science.gov (United States)

    Cakoni, Fioralba; Haddar, Houssem

    2013-10-01

    In inverse scattering theory, transmission eigenvalues can be seen as the extension of the notion of resonant frequencies for impenetrable objects to the case of penetrable dielectrics. The transmission eigenvalue problem is a relatively late arrival to the spectral theory of partial differential equations. Its first appearance was in 1986 in a paper by Kirsch who was investigating the denseness of far-field patterns for scattering solutions of the Helmholtz equation or, in more modern terminology, the injectivity of the far-field operator [1]. The paper of Kirsch was soon followed by a more systematic study by Colton and Monk in the context of developing the dual space method for solving the inverse scattering problem for acoustic waves in an inhomogeneous medium [2]. In this paper they showed that for a spherically stratified media transmission eigenvalues existed and formed a discrete set. Numerical examples were also given showing that in principle transmission eigenvalues could be determined from the far-field data. This first period of interest in transmission eigenvalues was concluded with papers by Colton et al in 1989 [3] and Rynne and Sleeman in 1991 [4] showing that for an inhomogeneous medium (not necessarily spherically stratified) transmission eigenvalues, if they existed, formed a discrete set. For the next seventeen years transmission eigenvalues were ignored. This was mainly due to the fact that, with the introduction of various sampling methods to determine the shape of an inhomogeneous medium from far-field data, transmission eigenvalues were something to be avoided and hence the fact that transmission eigenvalues formed at most a discrete set was deemed to be sufficient. In addition, questions related to the existence of transmission eigenvalues or the structure of associated eigenvectors were recognized as being particularly difficult due to the nonlinearity of the eigenvalue problem and the special structure of the associated transmission

  17. Anomalous sound propagation due to the horizontal variation of seabed acoustic properties

    Institute of Scientific and Technical Information of China (English)

    LI Zhenglin; ZHANG Renhe; PENG Zhaohui; LI Xilu

    2004-01-01

    The sound propagation in shallow water is greatly influenced by the acoustic properties of seabed. An anomalous transmission loss was observed in an experiment, and a range dependent bottom model with horizontal variation of seabed acoustic property is proposed and could be well used to explain the anomalous phenomena. It is shown that the horizontal variation of bottom properties has a great effect on underwater sound propagation, and it should be given much attention in sound propagation and geoacoustic inversion problems.

  18. Modeling horizontal gene transfer (HGT in the gut of the Chagas disease vector Rhodnius prolixus

    Directory of Open Access Journals (Sweden)

    Durvasula Ravi V

    2011-05-01

    Full Text Available Abstract Background Paratransgenesis is an approach to reducing arthropod vector competence using genetically modified symbionts. When applied to control of Chagas disease, the symbiont bacterium Rhodococcus rhodnii, resident in the gut lumen of the triatomine vector Rhodnius prolixus (Hemiptera: Reduviidae, is transformed to export cecropin A, an insect immune peptide. Cecropin A is active against Trypanosoma cruzi, the causative agent of Chagas disease. While proof of concept has been achieved in laboratory studies, a rigorous and comprehensive risk assessment is required prior to consideration of field release. An important part of this assessment involves estimating probability of transgene horizontal transfer to environmental organisms (HGT. This article presents a two-part risk assessment methodology: a theoretical model predicting HGT in the gut of R. prolixus from the genetically transformed symbiont R. rhodnii to a closely related non-target bacterium, Gordona rubropertinctus, in the absence of selection pressure, and a series of laboratory trials designed to test the model. Results The model predicted an HGT frequency of less than 1.14 × 10-16 per 100,000 generations at the 99% certainty level. The model was iterated twenty times, with the mean of the ten highest outputs evaluated at the 99% certainty level. Laboratory trials indicated no horizontal gene transfer, supporting the conclusions of the model. Conclusions The model treats HGT as a composite event, the probability of which is determined by the joint probability of three independent events: gene transfer through the modalities of transformation, transduction, and conjugation. Genes are represented in matrices and Monte Carlo method and Markov chain analysis are used to simulate and evaluate environmental conditions. The model is intended as a risk assessment instrument and predicts HGT frequency of less than 1.14 × 10-16 per 100,000 generations. With laboratory studies that

  19. Host immunostimulation and substrate utilization of the gut symbiont Akkermansia muciniphila

    NARCIS (Netherlands)

    Ottman, N.A.

    2015-01-01

    Host immunostimulation and substrate utilization of the gut symbiont Akkermansia muciniphila Noora A. Ottman The human gastrointestinal tract is colonized by a complex community of micro-organisms, the gut microbiota. The majority of these are bacteria, which perfor

  20. Complementary symbiont contributions to plant decomposition in a fungus-farming termite

    NARCIS (Netherlands)

    Poulsen, Michael; Hu, Haofu; Li, Cai; Chen, Zhensheng; Xu, Luohao; Otani, Saria; Nygaard, Sanne; Nobre, Tania; Klaubauf, S.; Schindler, Philipp M; Hauser, Frank; Pan, Hailin; Yang, Zhikai; Sonnenberg, Anton S M; de Beer, Z Wilhelm; Zhang, Yong; Wingfield, Michael J; Grimmelikhuijzen, Cornelis J P; de Vries, Ronald P; Korb, Judith; Aanen, Duur K; Wang, Jun; Boomsma, Jacobus J; Zhang, Guojie; van den Brink, J.

    2014-01-01

    Termites normally rely on gut symbionts to decompose organic matter but the Macrotermitinae domesticated Termitomyces fungi to produce their own food. This transition was accompanied by a shift in the composition of the gut microbiota, but the complementary roles of these bacteria in the symbiosis h

  1. Asymmetric interaction specificity between two sympatric termites and their fungal symbionts.

    NARCIS (Netherlands)

    Fine Licht, De H.H.; Boomsma, J.J.

    2007-01-01

    1. Fungus-growing termites live in an obligate mutualistic symbiosis with Termitomyces fungi. The functions of the fungal symbiont have been hypothesised to differ between species and to range from highly specific roles of providing plant-degrading enzymes complementary to termite gut enzymes, to no

  2. Metabolite profiling of symbiont and host during thermal stress and bleaching in the coral Acropora aspera

    Science.gov (United States)

    Hillyer, Katie E.; Dias, Daniel A.; Lutz, Adrian; Wilkinson, Shaun P.; Roessner, Ute; Davy, Simon K.

    2017-03-01

    Rising seawater temperatures pose a significant threat to the persistence of coral reefs. Despite the importance of these systems, major gaps remain in our understanding of how thermal stress and bleaching affect the metabolic networks that underpin holobiont function. We applied gas chromatography-mass spectrometry (GC-MS) metabolomics to detect changes in the intracellular free metabolite pools (polar and semi-polar compounds) of in hospite dinoflagellate symbionts and their coral hosts (and any associated microorganisms) during early- and late-stage thermal bleaching (a reduction of approximately 50 and 70% in symbiont density, respectively). We detected characteristic changes to the metabolite profiles of each symbiotic partner associated with individual cellular responses to thermal, oxidative and osmotic stress, which progressed with the severity of bleaching. Alterations were also indicative of changes to energy-generating and biosynthesis pathways in both partners, with a shift to the increased catabolism of lipid stores. Specifically, in symbiont intracellular metabolite pools, we observed accumulations of multiple free fatty acids, plus the chloroplast-associated antioxidant alpha-tocopherol. In the host, we detected a decline in the abundance of pools of multiple carbohydrates, amino acids and intermediates, in addition to the antioxidant ascorbate. These findings further our understanding of the metabolic changes that occur to symbiont and host (and its associated microorganisms) during thermal bleaching. These findings also provide further insight into the largely undescribed roles of free metabolite pools in cellular homeostasis, signalling and acclimation to thermal stress in the cnidarian-dinoflagellate symbiosis.

  3. Symbiont recognition of mutualistic bacteria by Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Zhang, Mingzi; Poulsen, Michael; Currie, Cameron R

    2007-01-01

    Symbiont choice has been proposed to play an important role in shaping many symbiotic relationships, including the fungus-growing ant-microbe mutualism. Over millions of years, fungus-growing ants have defended their fungus gardens from specialized parasites with antibiotics produced by an actino...

  4. Aiptasia sp. larvae as a model to reveal mechanisms of symbiont selection in cnidarians

    KAUST Repository

    Wolfowicz, Iliona

    2016-09-01

    Symbiosis, defined as the persistent association between two distinct species, is an evolutionary and ecologically critical phenomenon facilitating survival of both partners in diverse habitats. The biodiversity of coral reef ecosystems depends on a functional symbiosis with photosynthetic dinoflagellates of the highly diverse genus Symbiodinium, which reside in coral host cells and continuously support their nutrition. The mechanisms underlying symbiont selection to establish a stable endosymbiosis in non-symbiotic juvenile corals are unclear. Here we show for the first time that symbiont selection patterns for larvae of two Acropora coral species and the model anemone Aiptasia are similar under controlled conditions. We find that Aiptasia larvae distinguish between compatible and incompatible symbionts during uptake into the gastric cavity and phagocytosis. Using RNA-Seq, we identify a set of candidate genes potentially involved in symbiosis establishment. Together, our data complement existing molecular resources to mechanistically dissect symbiont phagocytosis in cnidarians under controlled conditions, thereby strengthening the role of Aiptasia larvae as a powerful model for cnidarian endosymbiosis establishment.

  5. Complete Genome Sequence of Bradyrhizobium diazoefficiens USDA 122, a Nitrogen-Fixing Soybean Symbiont

    Science.gov (United States)

    Sugawara, Masayuki; Tsukui, Takahiro; Kaneko, Takakazu; Ohtsubo, Yoshiyuki; Sato, Shusei; Nagata, Yuji; Tsuda, Masataka; Mitsui, Hisayuki

    2017-01-01

    ABSTRACT We report the complete genome sequence of Bradyrhizobium diazoefficiens USDA 122, a nitrogen-fixing soybean symbiont. The genome consists of a 9.1 Mb circular chromosome, and 8,551 coding sequences (CDSs) were predicted on the genome. The sequence will provide insight into the evolution of rhizobial genome, and the symbiotic compatibility with host plants. PMID:28254989

  6. Antitumor polyketide biosynthesis by an uncultivated bacterial symbiont of the marine sponge Theonella swinhoei.

    Science.gov (United States)

    Piel, Jörn; Hui, Dequan; Wen, Gaiping; Butzke, Daniel; Platzer, Matthias; Fusetani, Nobuhiro; Matsunaga, Shigeki

    2004-11-16

    Bacterial symbionts have long been suspected to be the true producers of many drug candidates isolated from marine invertebrates. Sponges, the most important marine source of biologically active natural products, have been frequently hypothesized to contain compounds of bacterial origin. This symbiont hypothesis, however, remained unproven because of a general inability to cultivate the suspected producers. However, we have recently identified an uncultured Pseudomonas sp. symbiont as the most likely producer of the defensive antitumor polyketide pederin in Paederus fuscipes beetles by cloning the putative biosynthesis genes. Here we report closely related genes isolated from the highly complex metagenome of the marine sponge Theonella swinhoei, which is the source of the onnamides and theopederins, a group of polyketides that structurally resemble pederin. Sequence features of the isolated genes clearly indicate that it belongs to a prokaryotic genome and should be responsible for the biosynthesis of almost the entire portion of the polyketide structure that is correlated with antitumor activity. Besides providing further proof for the role of the related beetle symbiont-derived genes, these findings raise intriguing ecological and evolutionary questions and have important general implications for the sustainable production of otherwise inaccessible marine drugs by using biotechnological strategies.

  7. Exploring the chemistry of uncultivated bacterial symbionts: antitumor polyketides of the pederin family.

    Science.gov (United States)

    Piel, Jörn; Butzke, Daniel; Fusetani, Nobuhiro; Hui, Dequan; Platzer, Matthias; Wen, Gaiping; Matsunaga, Shigeki

    2005-03-01

    Symbiotic bacteria have long been proposed as being responsible for the production of numerous natural products isolated from invertebrate animals. However, systematic studies of invertebrate-symbiont associations are usually associated with serious technical challenges, such as the general resistance of symbionts to culturing attempts and the complexity of many microbial consortia. Herein an overview is provided on the culture-independent, metagenomic strategies recently employed by our group to contribute to a better understanding of natural product symbiosis. Using terrestrial Paederus spp. beetles and the marine sponge Theonella swinhoei as model animals, the putative genes responsible for the production of pederin-type antitumor polyketides have been isolated. In Paederus fuscipes, which uses pederin for chemical defense, these genes belong to an as-yet unculturable symbiont closely related to Pseudomonas aeruginosa. To study the extremely complex association of T. swinhoei and its multispecies bacterial consortium, we used a phylogenetic approach that allowed the isolation of onnamide/theopederin polyketide synthase genes from an uncultured sponge symbiont. Analysis of the biosynthesis genes provided unexpected insights into a possible evolution of pederin-type pathways. Besides revealing new facets of invertebrate chemical ecology, these first gene clusters from uncultivated symbiotic producers suggest possible biotechnological strategies to solve the supply problem associated with the development of most marine drug candidates.

  8. Earthworms and their Nephridial Symbionts: Co-diversification and Maintenance of the Symbiosis

    DEFF Research Database (Denmark)

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

    ] and are vertically transmitted [3]. For these reasons we hypothesized that the earthworm-Verminephrobacter association evolved by co-diversification. This hypothesis was investigated by a comparison of earthworm and symbiont phylogenies. The earthworm phylogeny was based on Cytochrome c oxidase subunit I (COI...

  9. Symbiont shift towards Rhizobium nodulation in a group of phylogenetically related Phaseolus species.

    Science.gov (United States)

    Servín-Garcidueñas, Luis E; Zayas-Del Moral, Alejandra; Ormeño-Orrillo, Ernesto; Rogel, Marco A; Delgado-Salinas, Alfonso; Sánchez, Federico; Martínez-Romero, Esperanza

    2014-10-01

    Bean plants from the Phaseolus genus are widely consumed and represent a nitrogen source for human nutrition. They provide biological fertilization by establishing root nodule symbiosis with nitrogen-fixing bacteria. To establish a successful interaction, bean plants and their symbiotic bacteria need to synchronize a proper molecular crosstalk. Within the Phaseolus genus, P. vulgaris has been the prominent species to study nodulation with Rhizobium symbionts. However the Phaseolus genus comprises diverse species whose symbionts have not been analyzed. Here we identified and studied nodule bacteria from representative Phaseolus species not previously analyzed and from all the described wild species related to P. vulgaris. We found Bradyrhizobium in nodules from most species representing all Phaseolus clades except in five phylogenetically related species from the P. vulgaris clade. Therefore we propose that Bradyrhizobium nodulation is common in Phaseolus and that there was a symbiont preference shift to Rhizobium nodulation in few related species. This work sets the basis to further study the genetic basis of this symbiont substitution.

  10. Co-Speciation of Earthworms and their nephridial symbionts, Acidovorax Spp

    DEFF Research Database (Denmark)

    Lund, Marie Braad; Fritz, Michael; Holmstrup, Martin

    2006-01-01

    within the genus Acidovorax [2], and they are transmitted vertically [3]. For these reasons, we suggest that the earthworm-Acidovorax association has evolved by co-speciation. This hypothesis was tested by a comparative study of earthworm and symbiont phylogeny. Different earthworm species were collected...

  11. Unique genome evolution in an intracellular N2-fixing symbiont of a rhopalodiacean diatom

    Directory of Open Access Journals (Sweden)

    Takuro Nakayama

    2014-12-01

    Full Text Available Cyanobacteria, the major photosynthetic prokaryotic lineage, are also known as a major nitrogen fixer in nature. N2-fixing cyanobacteria are frequently found in symbioses with various types of eukaryotes and supply fixed nitrogen compounds to their eukaryotic hosts, which congenitally lack N2-fixing abilities. Diatom species belonging to the family Rhopalodiaceae also possess cyanobacterial symbionts called spheroid bodies. Unlike other cyanobacterial N2-fixing symbionts, the spheroid bodies reside in the cytoplasm of the diatoms and are inseparable from their hosts. Recently, the first spheroid body genome from a rhopalodiacean diatom has been completely sequenced. Overall features of the genome sequence showed significant reductive genome evolution resulting in a diminution of metabolic capacity. Notably, despite its cyanobacterial origin, the spheroid body was shown to be truly incapable of photosynthesis implying that the symbiont energetically depends on the host diatom. The comparative genome analysis between the spheroid body and another N2-fixing symbiotic cyanobacterial group corresponding to the UCYN-A phylotypes – both were derived from cyanobacteria closely related to genus Cyanothece – revealed that the two symbionts are on similar, but explicitly distinct tracks of reductive evolution. Intimate symbiotic relationships linked by nitrogen fixation as seen in rhopalodiacean diatoms may help us better understand the evolution and mechanisms of bacterium-eukaryote endosymbioses.

  12. Conditional fitness benefits of the Rickettsia bacterial symbiont in an insect pest.

    Science.gov (United States)

    Cass, Bodil N; Himler, Anna G; Bondy, Elizabeth C; Bergen, Jacquelyn E; Fung, Sierra K; Kelly, Suzanne E; Hunter, Martha S

    2016-01-01

    Inherited bacterial symbionts are common in arthropods and can have strong effects on the biology of their hosts. These effects are often mediated by host ecology. The Rickettsia symbiont can provide strong fitness benefits to its insect host, Bemisia tabaci, under laboratory and field conditions. However, the frequency of the symbiont is heterogeneous among field collection sites across the USA, suggesting that the benefits of the symbiont are contingent on additional factors. In two whitefly genetic lines collected from the same location, we tested the effect of Rickettsia on whitefly survival after heat shock, on whitefly competitiveness at different temperatures, and on whitefly competitiveness at different starting frequencies of Rickettsia. Rickettsia did not provide protection against heat shock nor affect the competitiveness of whiteflies at different temperatures or starting frequencies. However, there was a strong interaction between Rickettsia infection and whitefly genetic line. Performance measures indicated that Rickettsia was associated with significant female bias in both whitefly genetic lines, but in the second whitefly genetic line it conferred no significant fitness benefits nor conferred any competitive advantage to its host over uninfected whiteflies in population cages. These results help to explain other reports of variation in the phenotype of the symbiosis. Furthermore, they demonstrate the complex nature of these close symbiotic associations and the need to consider these interactions in the context of host population structure.

  13. Host immunostimulation and substrate utilization of the gut symbiont Akkermansia muciniphila

    NARCIS (Netherlands)

    Ottman, N.A.

    2015-01-01

    Host immunostimulation and substrate utilization of the gut symbiont Akkermansia muciniphila Noora A. Ottman The human gastrointestinal tract is colonized by a complex community of micro-organisms, the gut microbiota. The majority of these are bacteria, which perfor

  14. igh Symbiont Relatedness Stabilizes Mutualistic Cooperation in Fungus-Growing Termites

    NARCIS (Netherlands)

    Aanen, D.K.; Fine Licht, De H.H.; Debets, A.J.M.; Kerstes, N.A.G.; Hoekstra, R.F.; Boomsma, J.J.

    2009-01-01

    It is unclear how mutualistic relationships can be stable when partners disperse freely and have the possibility of forming associations with many alternative genotypes. Theory predicts that high symbiont relatedness should resolve this problem, but the mechanisms to enforce this have rarely been st

  15. The roles and interactions of symbiont, host and environment in defining coral fitness

    NARCIS (Netherlands)

    Mieog, J.C.; Olsen, J.L.; Berkelmans, R; Bleuler-Martinez, S.A.; Willis, B.; van Oppen, M.J H

    2009-01-01

    Background: Reef-building corals live in symbiosis with a diverse range of dinoflagellate algae ( genus Symbiodinium) that differentially influence the fitness of the coral holobiont. The comparative role of symbiont type in holobiont fitness in relation to host genotype or the environment, however,

  16. Marine Maladies? Worms, Germs, and Other Symbionts from the Northern Gulf of Mexico.

    Science.gov (United States)

    Overstreet, Robin M.

    Parasites and related symbionts of marine and estuarine hosts of the northern Gulf of Mexico are described in this guidebook. It is meant primarily to serve as a teaching aid for the novice student, but it also contains more technical aspects for the experienced parasitologist. Forms and examples of symbiosis are explained in an introductory…

  17. Comparative Genomics of Facultative Bacterial Symbionts Isolated from European Orius Species Reveals an Ancestral Symbiotic Association

    Directory of Open Access Journals (Sweden)

    Xiaorui Chen

    2017-10-01

    Full Text Available Pest control in agriculture employs diverse strategies, among which the use of predatory insects has steadily increased. The use of several species within the genus Orius in pest control is widely spread, particularly in Mediterranean Europe. Commercial mass rearing of predatory insects is costly, and research efforts have concentrated on diet manipulation and selective breeding to reduce costs and improve efficacy. The characterisation and contribution of microbial symbionts to Orius sp. fitness, behaviour, and potential impact on human health has been neglected. This paper provides the first genome sequence level description of the predominant culturable facultative bacterial symbionts associated with five Orius species (O. laevigatus, O. niger, O. pallidicornis, O. majusculus, and O. albidipennis from several geographical locations. Two types of symbionts were broadly classified as members of the genera Serratia and Leucobacter, while a third constitutes a new genus within the Erwiniaceae. These symbionts were found to colonise all the insect specimens tested, which evidenced an ancestral symbiotic association between these bacteria and the genus Orius. Pangenome analyses of the Serratia sp. isolates offered clues linking Type VI secretion system effector–immunity proteins from the Tai4 sub-family to the symbiotic lifestyle.

  18. Symbiotic adaptation drives genome streamlining of the cyanobacterial sponge symbiont "Candidatus Synechococcus pongiarum"

    KAUST Repository

    Gao, Zhao-Ming

    2014-04-01

    "Candidatus Synechococcus spongiarum" is a cyanobacterial symbiont widely distributed in sponges, but its functions at the genome level remain unknown. Here, we obtained the draft genome (1.66 Mbp, 90% estimated genome recovery) of "Ca. Synechococcus spongiarum" strain SH4 inhabiting the Red Sea sponge Carteriospongia foliascens. Phylogenomic analysis revealed a high dissimilarity between SH4 and free-living cyanobacterial strains. Essential functions, such as photosynthesis, the citric acid cycle, and DNA replication, were detected in SH4. Eukaryoticlike domains that play important roles in sponge-symbiont interactions were identified exclusively in the symbiont. However, SH4 could not biosynthesize methionine and polyamines and had lost partial genes encoding low-molecular-weight peptides of the photosynthesis complex, antioxidant enzymes, DNA repair enzymes, and proteins involved in resistance to environmental toxins and in biosynthesis of capsular and extracellular polysaccharides. These genetic modifications imply that "Ca. Synechococcus spongiarum" SH4 represents a low-light-adapted cyanobacterial symbiont and has undergone genome streamlining to adapt to the sponge\\'s mild intercellular environment. 2014 Gao et al.

  19. Long-term ungulate exclusion reduces fungal symbiont prevalence in native grasslands.

    Science.gov (United States)

    Rudgers, Jennifer A; Fletcher, Rebecca A; Olivas, Eric; Young, Carolyn A; Charlton, Nikki D; Pearson, Dean E; Maron, John L

    2016-08-01

    When symbionts are inherited by offspring, they can have substantial ecological and evolutionary consequences because they occur in all host life stages. Although natural frequencies of inherited symbionts are commonly endophytes can improve resistance to herbivory, growth under drought, and competitive ability. We evaluated whether native ungulate herbivory increased the prevalence of a fungal endophyte in the common, native bunchgrass, Festuca campestris (rough fescue, Poaceae). We used large-scale (1 ha) and long-term (7-10 year) fencing treatments to exclude native ungulates and recorded shifts in endophyte prevalence at the scale of plant populations and for individual plants. We characterized the fungal endophyte in F. campestris, Epichloë species FcaTG-1 (F. campestris taxonomic group 1) for the first time. Under ungulate exclusion, endophyte prevalence was 19 % lower in plant populations, 25 % lower within plant individuals, and 39 % lower in offspring (seeds) than in ungulate-exposed controls. Population-level endophyte frequencies were also negatively correlated with soil moisture across geographic sites. Observations of high within-plant variability in symbiont prevalence are novel for the Epichloë species, and contribute to a small, but growing, literature that documents phenotypic plasticity in plant-endophyte symbiota. Altogether, we show that native ungulates can be an important driver of symbiont prevalence in native plant populations, even in the absence of evidence for direct mechanisms of mammal deterrence. Understanding the ecological controls on symbiont prevalence could help to predict future shifts in grasslands that are dominated by Epichloë host plants.

  20. The roles and interactions of symbiont, host and environment in defining coral fitness.

    Directory of Open Access Journals (Sweden)

    Jos C Mieog

    Full Text Available BACKGROUND: Reef-building corals live in symbiosis with a diverse range of dinoflagellate algae (genus Symbiodinium that differentially influence the fitness of the coral holobiont. The comparative role of symbiont type in holobiont fitness in relation to host genotype or the environment, however, is largely unknown. We addressed this knowledge gap by manipulating host-symbiont combinations and comparing growth, survival and thermal tolerance among the resultant holobionts in different environments. METHODOLOGY/PRINCIPAL FINDINGS: Offspring of the coral, Acropora millepora, from two thermally contrasting locations, were experimentally infected with one of six Symbiodinium types, which spanned three phylogenetic clades (A, C and D, and then outplanted to the two parental field locations (central and southern inshore Great Barrier Reef, Australia. Growth and survival of juvenile corals were monitored for 31-35 weeks, after which their thermo-tolerance was experimentally assessed. Our results showed that: (1 Symbiodinium type was the most important predictor of holobiont fitness, as measured by growth, survival, and thermo-tolerance; (2 growth and survival, but not heat-tolerance, were also affected by local environmental conditions; and (3 host population had little to no effect on holobiont fitness. Furthermore, coral-algal associations were established with symbiont types belonging to clades A, C and D, but three out of four symbiont types belonging to clade C failed to establish a symbiosis. Associations with clade A had the lowest fitness and were unstable in the field. Lastly, Symbiodinium types C1 and D were found to be relatively thermo-tolerant, with type D conferring the highest tolerance in A. millepora. CONCLUSIONS/SIGNIFICANCE: These results highlight the complex interactions that occur between the coral host, the algal symbiont, and the environment to shape the fitness of the coral holobiont. An improved understanding of the factors

  1. Contrasting physiological plasticity in response to environmental stress within different cnidarians and their respective symbionts

    Science.gov (United States)

    Hoadley, Kenneth D.; Pettay, Daniel. T.; Dodge, Danielle; Warner, Mark E.

    2016-06-01

    Given concerns surrounding coral bleaching and ocean acidification, there is renewed interest in characterizing the physiological differences across the multiple host-algal symbiont combinations commonly found on coral reefs. Elevated temperature and CO2 were used to compare physiological responses within the scleractinian corals Montipora hirsuta ( Symbiodinium C15) and Pocillopora damicornis ( Symbiodinium D1), as well as the corallimorph (a non-calcifying anthozoan closely related to scleractinians) Discosoma nummiforme ( Symbiodinium C3). Several physiological proxies were affected more by temperature than CO2, including photochemistry, algal number and cellular chlorophyll a. Marked differences in symbiont number, chlorophyll and volume contributed to distinctive patterns of chlorophyll absorption among these animals. In contrast, carbon fixation either did not change or increased under elevated temperature. Also, the rate of photosynthetically fixed carbon translocated to each host did not change, and the percent of carbon translocated to the host increased in the corallimorph. Comparing all data revealed a significant negative correlation between photosynthetic rate and symbiont density that corroborates previous hypotheses about carbon limitation in these symbioses. The ratio of symbiont-normalized photosynthetic rate relative to the rate of symbiont-normalized carbon translocation (P:T) was compared in these organisms as well as the anemone, Exaiptasia pallida hosting Symbiodinium minutum, and revealed a P:T close to unity ( D. nummiforme) to a range of 2.0-4.5, with the lowest carbon translocation in the sea anemone. Major differences in the thermal responses across these organisms provide further evidence of a range of acclimation potential and physiological plasticity that highlights the need for continued study of these symbioses across a larger group of host taxa.

  2. Does coral disease affect symbiodinium? Investigating the impacts of growth anomaly on symbiont photophysiology.

    Directory of Open Access Journals (Sweden)

    John Henrik Robert Burns

    Full Text Available Growth anomaly (GA is a commonly observed coral disease that impairs biological functions of the affected tissue. GA is prevalent at Wai 'ōpae tide pools, southeast Hawai 'i Island. Here two distinct forms of this disease, Type A and Type B, affect the coral, Montiporacapitata. While the effects of GA on biology and ecology of the coral host are beginning to be understood, the impact of this disease on the photophysiology of the dinoflagellate symbiont, Symbiodinium spp., has not been investigated. The GA clearly alters coral tissue structure and skeletal morphology and density. These tissue and skeletal changes are likely to modify not only the light micro-environment of the coral tissue, which has a direct impact on the photosynthetic potential of Symbiodinium spp., but also the physiological interactions within the symbiosis. This study utilized Pulse amplitude modulation fluorometry (PAM to characterize the photophysiology of healthy and GA-affected M. capitata tissue. Overall, endosymbionts within GA-affected tissue exhibit reduced photochemical efficiency. Values of both Fv/Fm and ΔF/ Fm' were significantly lower (p<0.01 in GA tissue compared to healthy and unaffected tissues. Tracking the photophysiology of symbionts over a diurnal time period enabled a comparison of symbiont responses to photosynthetically available radiation (PAR among tissue conditions. Symbionts within GA tissue exhibited the lowest values of ΔF/Fm' as well as the highest pressure over photosystem II (p<0.01. This study provides evidence that the symbionts within GA-affected tissue are photochemically compromised compared to those residing in healthy tissue.

  3. Relationships between host and symbiont cell cycles in sea anemones and their symbiotic dinoflagellates.

    Science.gov (United States)

    Dimond, James L; Pineda, Rea R; Ramos-Ascherl, Zullaylee; Bingham, Brian L

    2013-10-01

    The processes by which cnidarians and their algal endosymbionts achieve balanced growth and biomass could include coordination of host and symbiont cell cycles. We evaluated this theory with natural populations of sea anemones hosting symbiotic dinoflagellates, focusing on the temperate sea anemone Anthopleura elegantissima symbiotic with Symbiodinium muscatinei in Washington State, USA, and the tropical anemone Stichodactyla helianthus associating with unknown Symbiodinium spp. in Belize. By extruding symbiont-containing gastrodermal cells from the relatively large tentacles of these species and using nuclear staining and flow cytometry, we selectively analyzed cell cycle distributions of the symbionts and the host gastrodermal cells that house them. We found no indications of diel synchrony in host and symbiont G2/M phases, and we observed evidence of diel periodicity only in Symbiodinium spp. associated with S. helianthus but not in the anemone itself. Seasonally, S. muscatinei showed considerable G2/M phase variability among samples collected quarterly over an annual period, while the G2/M phase of its host varied much less. Within samples taken at different times of the year, correlations between host and symbiont G2/M phases ranged from very weakly to very strongly positive, with significant correlations in only half of the samples (two of four A. elegantissima samples and one of two S. helianthus samples). Overall, the G2/M phase relationships across species and sampling periods were positive. Thus, while we found no evidence of close cell cycle coupling, our results suggest a loose, positive relationship between cell cycle processes of the symbiotic partners.

  4. A Rhizosphere-Associated Symbiont, Photobacterium spp. Strain MELD1, and Its Targeted Synergistic Activity for Phytoprotection against Mercury

    Science.gov (United States)

    Mathew, Dony Chacko; Ho, Ying-Ning; Gicana, Ronnie Gicaraya; Mathew, Gincy Marina; Chien, Mei-Chieh; Huang, Chieh-Chen

    2015-01-01

    Though heavy metal such as mercury is toxic to plants and microorganisms, the synergistic activity between them may offer benefit for surviving. In this study, a mercury-reducing bacterium, Photobacterium spp. strain MELD1, with an MIC of 33 mg . kg-1 mercury was isolated from a severely mercury and dioxin contaminated rhizosphere soil of reed (Phragmites australis). While the whole genome sequencing of MELD1 confirmed the presence of a mer operon, the mercury reductase MerA gene showed 99% sequence identity to Vibrio shilloni AK1 and implicates its route resulted from the event of horizontal gene transfer. The efficiency of MELD1 to vaporize mercury (25 mg . kg-1, 24 h) and its tolerance to toxic metals and xenobiotics such as lead, cadmium, pentachlorophenol, pentachloroethylene, 3-chlorobenzoic acid, 2,3,7,8-tetrachlorodibenzo-p-dioxin and 1,2,3,7,8,9-hexachlorodibenzo-p-dioxin is promising. Combination of a long yard bean (Vigna unguiculata ssp. Sesquipedalis) and strain MELD1 proved beneficial in the phytoprotection of mercury in vivo. The effect of mercury (Hg) on growth, distribution and tolerance was examined in root, shoot, leaves and pod of yard long bean with and without the inoculation of strain MELD1. The model plant inoculated with MELD1 had significant increases in biomass, root length, seed number, and increased mercury uptake limited to roots. Biolog plate assay were used to assess the sole-carbon source utilization pattern of the isolate and Indole-3-acetic acid (IAA) productivity was analyzed to examine if the strain could contribute to plant growth. The results of this study suggest that, as a rhizosphere-associated symbiont, the synergistic activity between the plant and MELD1 can improve the efficiency for phytoprotection, phytostabilization and phytoremediation of mercury. PMID:25816328

  5. Panspermia and horizontal gene transfer

    Science.gov (United States)

    Klyce, Brig

    2009-08-01

    Evidence that extremophiles are hardy and ubiquitous is helping to make panspermia a respectable theory. But even if life on Earth originally came from space, biologists assume that the subsequent evolution of life is still governed by the darwinian paradigm. In this review we show how panspermia could amend darwinism and point to a cosmic source for, not only extremophiles but, all of life. This version of panspermia can be called "strong panspermia." To support this theory we will discuss recent evidence pertaining to horizontal gene transfer, viruses, genes apparently older than the Earthly evolution of the features they encode, and primate-specific genes without identifiable precursors.

  6. The evolution of transmission mode

    Science.gov (United States)

    Forbes, Mark R.; Hauffe, Heidi C.; Kallio, Eva R.; Okamura, Beth; Sait, Steven M.

    2017-01-01

    This article reviews research on the evolutionary mechanisms leading to different transmission modes. Such modes are often under genetic control of the host or the pathogen, and often in conflict with each other via trade-offs. Transmission modes may vary among pathogen strains and among host populations. Evolutionary changes in transmission mode have been inferred through experimental and phylogenetic studies, including changes in transmission associated with host shifts and with evolution of the unusually complex life cycles of many parasites. Understanding the forces that determine the evolution of particular transmission modes presents a fascinating medley of problems for which there is a lack of good data and often a lack of conceptual understanding or appropriate methodologies. Our best information comes from studies that have been focused on the vertical versus horizontal transmission dichotomy. With other kinds of transitions, theoretical approaches combining epidemiology and population genetics are providing guidelines for determining when and how rapidly new transmission modes may evolve, but these are still in need of empirical investigation and application to particular cases. Obtaining such knowledge is a matter of urgency in relation to extant disease threats. This article is part of the themed issue ‘Opening the black box: re-examining the ecology and evolution of parasite transmission’. PMID:28289251

  7. Horizontal gene transfer—emerging multidrug resistance in hospital bacteria

    Institute of Scientific and Technical Information of China (English)

    SenkaDZIDIC; VladimirBEDEKOVIC

    2003-01-01

    The frequency and spectrum of antibiotic resistant infections have increased worldwide during the past few decades. This increase has been attributed to a combination of microbial characteristics, the selective pressure of antimicrobial use, and social and technical changes that enhance the transmission of resistant organisms. The resistance is acquired by mutational changer or by the acquisition of resistance-encoding genetic material which is transfered from another bacteria. The spread of antibiotic resistance genes may be causally related to the overuse of antibiotics in human health care and in animal feeds, increased use of invasive devices and procedures, a greater number of susceptible hosts, and lapses in infection control practices leading to increased transmission of resistant organisms. The resistance gene sequences are integrated by recombination into several classes of naturally occurring gene expression cassettes and disseminated within the microbial population by horizontal gene transfer mechanisms: transformation, conjugation or transduction. In the hospital, widespread use of antimicrobials in the intensive care units (ICU) and for immunocompromised patients has resulted in the selection of multidrug-resistant organisms. Methicilin-resistant Staphylococci, vancomycin resistant Enterococci and extended-spectrum betalactamase(ESBL) producing Gram negative bacilli are identified as major phoblem in nosocomial infections. Recent surveillance studies have demonstrated trend towares more seriously ill patients suffering from multidrug-resistant nosocomial infections. Emergence of multiresistant bacteria and spread of resistance genes should enforce the aplication of strict prevention strategies, including changes in antibiotic treatment regimens, hygiene measures, infection prevention and control of horizontal nosocomial transmission of organisms.

  8. Horizontal gene transfer in chromalveolates

    Directory of Open Access Journals (Sweden)

    Bhattacharya Debashish

    2007-09-01

    Full Text Available Abstract Background Horizontal gene transfer (HGT, the non-genealogical transfer of genetic material between different organisms, is considered a potentially important mechanism of genome evolution in eukaryotes. Using phylogenomic analyses of expressed sequence tag (EST data generated from a clonal cell line of a free living dinoflagellate alga Karenia brevis, we investigated the impact of HGT on genome evolution in unicellular chromalveolate protists. Results We identified 16 proteins that have originated in chromalveolates through ancient HGTs before the divergence of the genera Karenia and Karlodinium and one protein that was derived through a more recent HGT. Detailed analysis of the phylogeny and distribution of identified proteins demonstrates that eight have resulted from independent HGTs in several eukaryotic lineages. Conclusion Recurring intra- and interdomain gene exchange provides an important source of genetic novelty not only in parasitic taxa as previously demonstrated but as we show here, also in free-living protists. Investigating the tempo and mode of evolution of horizontally transferred genes in protists will therefore advance our understanding of mechanisms of adaptation in eukaryotes.

  9. Horizontal versus vertical plate motions

    Directory of Open Access Journals (Sweden)

    M. Cuffaro

    2006-07-01

    Full Text Available We review both present and past motions at major plate boundaries, which have the horizontal component in average 10 to 100 times faster (10–100 mm/yr than the vertical component (0.01–1 mm/yr in all geodynamic settings. The steady faster horizontal velocity of the lithosphere with respect to the upward or downward velocities at plate boundaries supports dominating tangential forces acting on plates. This suggests a passive role of plate boundaries with respect to far field forces determining the velocity of plates. The forces acting on the lithosphere can be subdivided in coupled and uncoupled, as a function of the shear at the lithosphere base. Higher the asthenosphere viscosity, more significant should be the coupled forces, i.e., the mantle drag and the trench suction. Lower the asthenosphere viscosity, more the effects of uncoupled forces might result determinant, i.e., the ridge push, the slab pull and the tidal drag. Although a combination of all forces acting on the lithosphere is likely, the decoupling between lithosphere and mantle suggests that a torque acts on the lithosphere independently of the mantle drag. Slab pull and ridge push are candidates for generating this torque, but, unlike these boundary forces, the advantage of the tidal drag is to be a volume force, acting simultaneously on the whole plates, and being the decoupling at the lithosphere base controlled by lateral variations in viscosity of the low-velocity layer.

  10. Effects of ocean acidification on calcification of symbiont-bearing reef foraminifers

    Directory of Open Access Journals (Sweden)

    K. Fujita

    2011-08-01

    Full Text Available Ocean acidification (decreases in carbonate ion concentration and pH in response to rising atmospheric pCO2 is generally expected to reduce rates of calcification by reef calcifying organisms, with potentially severe implications for coral reef ecosystems. Large, algal symbiont-bearing benthic foraminifers, which are important primary and carbonate producers in coral reefs, produce high-Mg calcite shells, whose solubility can exceed that of aragonite produced by corals, making them the "first responder" in coral reefs to the decreasing carbonate saturation state of seawater. Here we report results of culture experiments performed to assess the effects of ongoing ocean acidification on the calcification of symbiont-bearing reef foraminifers using a high-precision pCO2 control system. Living clone individuals of three foraminiferal species (Baculogypsina sphaerulata, Calcarina gaudichaudii, and Amphisorus hemprichii were subjected to seawater at five pCO2 levels from 260 to 970 μatm. Cultured individuals were maintained for about 12 weeks in an indoor flow-through system under constant water temperature, light intensity, and photoperiod. After the experiments, the shell diameter and weight of each cultured specimen were measured. Net calcification of B. sphaerulata and C. gaudichaudii, which secrete a hyaline shell and host diatom symbionts, increased under intermediate levels of pCO2 (580 and/or 770 μatm and decreased at a higher pCO2 level (970 μatm. Net calcification of A. hemprichii, which secretes a porcelaneous shell and hosts dinoflagellate symbionts, tended to decrease at elevated pCO2. Observed different responses between hyaline and porcelaneous species are possibly caused by the relative importance of elevated pCO2, which induces CO2 fertilization effects by

  11. A novel extracellular gut symbiont in the marine worm Priapulus caudatus (Priapulida) reveals an alphaproteobacterial symbiont clade of the Ecdysozoa

    DEFF Research Database (Denmark)

    Kroer, Paul; Kjeldsen, Kasper Urup; Nyengaard, Jens Randel

    2016-01-01

    Priapulus caudatus (phylum Priapulida) is a benthic marine predatory worm with a cosmopolitan distribution. In its digestive tract we detected symbiotic bacteria that were consistently present in specimens collected over eight years from three sites at the Swedish west coast. Based on their 16S r......RNA gene sequence, these symbionts comprise a novel genus of the order Rickettsiales (Alphaproteobacteria). Electron microscopy and fluorescence in situ hybridization (FISH) identified them as extracellular, elongate bacteria closely associated with the microvilli, for which we propose the name ‘Candidatus...

  12. Loss of genes related to Nucleotide Excision Repair (NER) and implications for reductive genome evolution in symbionts of deep-sea vesicomyid clams

    Science.gov (United States)

    Shimamura, Shigeru; Kaneko, Takashi; Ozawa, Genki; Matsumoto, Mamiko Nishino; Koshiishi, Takeru; Takaki, Yoshihiro; Kato, Chiaki; Takai, Ken; Yoshida, Takao; Fujikura, Katsunori; Barry, James P.

    2017-01-01

    Intracellular thioautotrophic symbionts of deep-sea vesicomyid clams lack some DNA repair genes and are thought to be undergoing reductive genome evolution (RGE). In this study, we addressed two questions, 1) how these symbionts lost their DNA repair genes and 2) how such losses affect RGE. For the first question, we examined genes associated with nucleotide excision repair (NER; uvrA, uvrB, uvrC, uvrD, uvrD paralog [uvrDp] and mfd) in 12 symbionts of vesicomyid clams belonging to two clades (5 clade I and 7 clade II symbionts). While uvrA, uvrDp and mfd were conserved in all symbionts, uvrB and uvrC were degraded in all clade I symbionts but were apparently intact in clade II symbionts. UvrD was disrupted in two clade II symbionts. Among the intact genes in Ca. Vesicomyosocius okutanii (clade I), expressions of uvrD and mfd were detected by reverse transcription-polymerase chain reaction (RT-PCR), but those of uvrA and uvrDp were not. In contrast, all intact genes were expressed in the symbiont of Calyptogena pacifica (clade II). To assess how gene losses affect RGE (question 2), genetic distances of the examined genes in symbionts from Bathymodiolus septemdierum were shown to be larger in clade I than clade II symbionts. In addition, these genes had lower guanine+cytosine (GC) content and higher repeat sequence densities in clade I than measured in clade II. Our results suggest that NER genes are currently being lost from the extant lineages of vesicomyid clam symbionts. The loss of NER genes and mutY in these symbionts is likely to promote increases in genetic distance and repeat sequence density as well as reduced GC content in genomic genes, and may have facilitated reductive evolution of the genome. PMID:28199404

  13. Explorando nuevos horizontes en NASA

    Science.gov (United States)

    Villanueva, G. L.

    A pesar de la incesante expansión del Universo iniciada con el Big Bang 14 mil millones de años atrás, nuestro Universo se siente cada día más cercano. La inquebrantable vocación de la humanidad por descubrir nuevos horizontes ha permitido el acercamiento de civilizaciones en nuestro planeta y nos ha permitido conocer nuestro lugar en el Universo como nunca antes. En este artículo presento una breve sinopsis de nuestro trabajo que se relaciona con diversas investigaciones con implicaciones astrobiológicas, desde el origen de los ingredientes de la "sopa de la vida", hasta la evolución y composición de la atmósfera de Marte.

  14. Location of Symbionts in the Whitefly Bemisia tabaci Affects Their Densities during Host Development and Environmental Stress

    Science.gov (United States)

    Su, Qi; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Ghanim, Murad; Zhang, Youjun

    2014-01-01

    Bacterial symbionts often enhance the physiological capabilities of their arthropod hosts and enable their hosts to expand into formerly unavailable niches, thus leading to biological diversification. Many arthropods, including the worldwide invasive whitefly Bemisia tabaci, have individuals simultaneously infected with symbionts of multiple genera that occur in different locations in the host. This study examined the population dynamics of symbionts that are located in different areas within B. tabaci. While densities of Portiera and Hamiltonella (which are located in bacteriocytes) appeared to be well-regulated during host development, densities of Rickettsia (which are not located in bacteriocytes) were highly variable among individual hosts during host development. Host mating did not significantly affect symbiont densities. Infection by Tomato yellow leaf curl virus did not affect Portiera and Hamiltonella densities in either sex, but increased Rickettsia densities in females. High and low temperatures did not affect Portiera and Hamiltonella densities, but low temperature (15°C) significantly suppressed Rickettsia densities whereas high temperature (35°C) had little effect on Rickettsia densities. The results are consistent with the view that the population dynamics of bacterial symbionts in B. tabaci are regulated by symbiont location within the host and that the regulation reflects adaptation between the bacteria and insect. PMID:24632746

  15. Anthropogenic perturbation of coral reef environments near Natal, Brazil: Clues from symbiont-bearing benthic foraminifera

    Science.gov (United States)

    Eichler, P.; Vital, H.; Sen Gupta, B. K.

    2014-12-01

    Besides global stressors such as temperature rise and acidification, local anthropogenic disturbances, especially those connected with tourism, affect many Atlantic patch reefs off the Brazilian shore. Using reef-inhabiting foraminifera with algal symbionts as environmental indicators, we confirmed this problem in coastal reefs near Natal, Rio Grande do Norte. The foraminiferal community is particularly depauperate in the small reefs of Pirangi, about 25 km south of Natal (~6o S, water depth tourism. However, living Amphistegina is still rare, and the only living Amphisorus is found in seagrass habitats. In contrast, many symbiont-bearing taxa, including peneroplids (virtually absent in Pirangi and Maracajaú) exist in sizeable populations northwest of Maracajaú, in the small patch reefs of the drowned Açu river valley (~4o 50' S).

  16. Variable interaction specificity and symbiont performance in Panamanian Trachymyrmex and Sericomyrmex fungus-growing ants

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Boomsma, Jacobus Jan

    2014-01-01

    Background Cooperative benefits of mutualistic interactions are affected by genetic variation among the interacting partners, which may have consequences for interaction-specificities across guilds of sympatric species with similar mutualistic life histories. The gardens of fungus-growing (attine...... and Sericomyrmex higher attine ants in Gamboa, Panama provided the opportunity to do a quantitative study of species-level interaction-specificity. Results We genotyped the ants for Cytochrome Oxidase and their Leucoagaricus fungal cultivars for ITS rDNA. Combined with activity measurements for 12 carbohydrate...... cultivar symbiont-specificity varied from almost full symbiont sharing to one-to-one specialization, suggesting that trade-offs between enzyme activity spectra and life-history traits such as desiccation tolerance, disease susceptibility and temperature sensitivity may apply in some combinations...

  17. Horizontal acquisition of toxic alkaloid synthesis in a clade of plant associated fungi.

    Science.gov (United States)

    Marcet-Houben, Marina; Gabaldón, Toni

    2016-01-01

    Clavicipitaceae is a fungal group that comprises species that closely interact with plants as pathogens, parasites or symbionts. A key factor in these interactions is the ability of these fungi to synthesize toxic alkaloid compounds that contribute to the protection of the plant host against herbivores. Some of these compounds such as ergot alkaloids are toxic to humans and have caused important epidemics throughout history. The gene clusters encoding the proteins responsible for the synthesis of ergot alkaloids and lolines in Clavicipitaceae have been elucidated. Notably, homologs to these gene clusters can be found in distantly related species such as Aspergillus fumigatus and Penicillium expansum, which diverged from Clavicipitaceae more than 400 million years ago. We here use a phylogenetic approach to analyze the evolution of these gene clusters. We found that the gene clusters conferring the ability to synthesize ergot alkaloids and loline emerged first in Eurotiomycetes and were then likely transferred horizontally to Clavicipitaceae. Horizontal gene transfer is known to play a role in shaping the distribution of secondary metabolism clusters across distantly related fungal species. We propose that HGT events have played an important role in the capability of Clavicipitaceae to produce two key secondary metabolites that have enhanced the ability of these species to protect their plant hosts, therefore favoring their interactions.

  18. Optimization of horizontal well staggered patterns

    Institute of Scientific and Technical Information of China (English)

    Zhao Chunsen; Li Peijing; Guan Dan; Liu Qingjuan

    2008-01-01

    Staggered line-drive patterns are widely used in oilfields. In this paper, to optimize a staggered pattern of horizontal wells, a 3D problem was divided into two 2D (x-y plane and y-z plane) problems with the pseudo-3D method, conformal transformation and superposition principle. A productivity equation for a horizontal well was deduced, which can be used to optimize the well pattern. A relationship between the length of horizontal wells and the shape factor of well patterns was established. The result shows that optimized well patterns can improve oil production from horizontal wells. This provides a theoretical basis for horizontal well applications to the development of oilfieids, especially for overall development of oilfields by horizontal wells.

  19. TonB-dependent heme iron acquisition in the tsetse fly symbiont Sodalis glossinidius.

    Science.gov (United States)

    Hrusa, Gili; Farmer, William; Weiss, Brian L; Applebaum, Taylor; Roma, Jose Santinni; Szeto, Lauren; Aksoy, Serap; Runyen-Janecky, Laura J

    2015-04-01

    Sodalis glossinidius is an intra- and extracellular symbiont of the tsetse fly (Glossina sp.), which feeds exclusively on vertebrate blood. S. glossinidius resides in a wide variety of tsetse tissues and may encounter environments that differ dramatically in iron content. The Sodalis chromosome encodes a putative TonB-dependent outer membrane heme transporter (HemR) and a putative periplasmic/inner membrane ABC heme permease system (HemTUV). Because these gene products mediate iron acquisition processes by other enteric bacteria, we characterized their regulation and physiological role in the Sodalis/tsetse system. Our results show that the hemR and tonB genes are expressed by S. glossinidius in the tsetse fly. Furthermore, transcription of hemR in Sodalis is repressed in a high-iron environment by the iron-responsive transcriptional regulator Fur. Expression of the S. glossinidius hemR and hemTUV genes in an Escherichia coli strain unable to use heme as an iron source stimulated growth in the presence of heme or hemoglobin as the sole iron source. This stimulation was dependent on the presence of either the E. coli or Sodalis tonB gene. Sodalis tonB and hemR mutant strains were defective in their ability to colonize the gut of tsetse flies that lacked endogenous symbionts, while wild-type S. glossinidius proliferated in this same environment. Finally, we show that the Sodalis HemR protein is localized to the bacterial membrane and appears to bind hemin. Collectively, this study provides strong evidence that TonB-dependent, HemR-mediated iron acquisition is important for the maintenance of symbiont homeostasis in the tsetse fly, and it provides evidence for the expression of bacterial high-affinity iron acquisition genes in insect symbionts. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  20. The distribution of intra-genomically variable dinoflagellate symbionts at Lord Howe Island, Australia

    Science.gov (United States)

    Wilkinson, Shaun P.; Pontasch, Stefanie; Fisher, Paul L.; Davy, Simon K.

    2016-06-01

    The symbiotic dinoflagellates of corals and other marine invertebrates ( Symbiodinium) are essential to the development of shallow-water coral reefs. This genus contains considerable genetic diversity and a corresponding range of physiological and ecological traits. Most genetic variation arises through the accumulation of somatic mutations that arise during asexual reproduction. Yet growing evidence suggests that occasional sexual reproductive events also occur within, and perhaps between, Symbiodinium lineages, further contributing to the pool of genetic variation available for evolutionary adaptation. Intra-genomic variation can therefore arise from both sexual and asexual reproductive processes, making it difficult to discern its underlying causes and consequences. We used quantitative PCR targeting the ITS2 locus to estimate proportions of genetically homogeneous symbionts and intra-genomically variable Symbiodinium (IGV Symbiodinium) in the reef-building coral Pocillopora damicornis at Lord Howe Island, Australia. We then sampled colonies through time and at a variety of spatial scales to find out whether the distribution of these symbionts followed patterns consistent with niche partitioning. Estimated ratios of homogeneous to IGV Symbiodinium varied between colonies within sites (metres to tens of metres) and between sites separated by hundreds to thousands of metres, but remained stable within colonies through time. Symbiont ratios followed a temperature gradient, with the local thermal maximum emerging as a negative predictor for the estimated proportional abundance of IGV Symbiodinium. While this pattern may result from fine-scale spatial population structure, it is consistent with an increased susceptibility to thermal stress, suggesting that the evolutionary processes that generate IGV (such as inter-lineage recombination and the accumulation of somatic mutations at the ITS2 locus) may have important implications for the fitness of the symbiont and

  1. Host-symbiont relationships in hydrothermal vent gastropods of the genus Alviniconcha from the Southwest Pacific.

    Science.gov (United States)

    Suzuki, Yohey; Kojima, Shigeaki; Sasaki, Takenori; Suzuki, Masae; Utsumi, Takashi; Watanabe, Hiromi; Urakawa, Hidetoshi; Tsuchida, Shinji; Nunoura, Takuro; Hirayama, Hisako; Takai, Ken; Nealson, Kenneth H; Horikoshi, Koki

    2006-02-01

    Hydrothermal vent gastropods of the genus Alviniconcha are unique among metazoans in their ability to derive their nutrition from chemoautotrophic gamma- and epsilon-proteobacterial endosymbionts. Although host-symbiont relationships in Alviniconcha gastropods from the Central Indian Ridge in the Indian Ocean and the Mariana Trough in the Western Pacific have been studied extensively, host-symbiont relationships in Alviniconcha gastropods from the Southwest Pacific remain largely unknown. Phylogenetic analysis using mitochondrial cytochrome c oxidase subunit I gene sequences of host gastropods from the Manus, North Fiji, and Lau Back-Arc Basins in the Southwest Pacific has revealed a new host lineage in a Alviniconcha gastropod from the Lau Basin and the occurrence of the host lineage Alviniconcha sp. type 2 in the Manus Basin. Based on 16S rRNA gene sequences of bacterial endosymbionts, two gamma-proteobacterial lineages and one epsilon-proteobacterial lineage were identified in the present study. The carbon isotopic compositions of the biomass and fatty acids of the gastropod tissues suggest that the gamma- and epsilon-proteobacterial endosymbionts mediate the Calvin-Benson cycle and the reductive tricarboxylic acid cycle, respectively, for their chemoautotrophic growth. Coupling of the host and symbiont lineages from the three Southwest Pacific basins revealed that each of the Alviniconcha lineages harbors different bacterial endosymbionts belonging to either the gamma- or epsilon-Proteobacteria. The host specificity exhibited in symbiont selection provides support for the recognition of each of the host lineages as a distinct species. The results from the present study also suggest the possibility that Alviniconcha sp. types 1 and 2 separately inhabit hydrothermal vent sites approximately 120 m apart in the North Fiji Basin and 500 m apart in the Manus Basin.

  2. Pyrosequencing of bacterial symbionts within Axinella corrugata sponges: diversity and seasonal variability.

    Directory of Open Access Journals (Sweden)

    James R White

    Full Text Available BACKGROUND: Marine sponge species are of significant interest to many scientific fields including marine ecology, conservation biology, genetics, host-microbe symbiosis and pharmacology. One of the most intriguing aspects of the sponge "holobiont" system is the unique physiology, interaction with microbes from the marine environment and the development of a complex commensal microbial community. However, intraspecific variability and temporal stability of sponge-associated bacterial symbionts remain relatively unknown. METHODOLOGY/PRINCIPAL FINDINGS: We have characterized the bacterial symbiont community biodiversity of seven different individuals of the Caribbean reef sponge Axinella corrugata, from two different Florida reef locations during variable seasons using multiplex 454 pyrosequencing of 16 S rRNA amplicons. Over 265,512 high-quality 16 S rRNA sequences were generated and analyzed. Utilizing versatile bioinformatics methods and analytical software such as the QIIME and CloVR packages, we have identified 9,444 distinct bacterial operational taxonomic units (OTUs. Approximately 65,550 rRNA sequences (24% could not be matched to bacteria at the class level, and may therefore represent novel taxa. Differentially abundant classes between seasonal Axinella communities included Gammaproteobacteria, Flavobacteria, Alphaproteobacteria, Cyanobacteria, Acidobacter and Nitrospira. Comparisons with a proximal outgroup sponge species (Amphimedon compressa, and the growing sponge symbiont literature, indicate that this study has identified approximately 330 A. corrugata-specific symbiotic OTUs, many of which are related to the sulfur-oxidizing Ectothiorhodospiraceae. This family appeared exclusively within A. corrugata, comprising >34.5% of all sequenced amplicons. Other A. corrugata symbionts such as Deltaproteobacteria, Bdellovibrio, and Thiocystis among many others are described. CONCLUSIONS/SIGNIFICANCE: Slight shifts in several bacterial taxa

  3. Genetic Diversity of Nostoc Symbionts Endophytically Associated with Two Bryophyte Species

    OpenAIRE

    Costa, José-Luis; Paulsrud, Per; Rikkinen, Jouko; Lindblad, Peter

    2001-01-01

    The diversity of the endophytic Nostoc symbionts of two thalloid bryophytes, the hornwort Anthoceros fusiformis and the liverwort Blasia pusilla, was examined using the tRNALeu (UAA) intron sequence as a marker. The results confirmed that many different Nostoc strains are involved in both associations under natural conditions in the field. The level of Nostoc diversity within individual bryophyte thalli varied, but single DNA fragments were consistently amplified from individual symbiotic col...

  4. Bacterial Endo-Symbiont Inhabiting Tridax procumbens L. and Their Antimicrobial Potential

    OpenAIRE

    Syed Baker; Kumara Shanthamma Kavitha; Huvinakola Chinnappa Yashavantha Rao; Devaraju Rakshith; Ballagere Puttaraju Harini; Komal Kumar; Sreedharamurthy Satish

    2015-01-01

    Bacterial symbionts inhabiting Tridax procumbens L. were screened for antimicrobial potential with the aim to isolate potent bacteria bearing significant activity against test pathogens. The selected isolate was subjected to large scale fermentation to extract antimicrobial metabolite. The organic phase was reduced under vacuum pressure and crude ethyl acetate extract (10 mg/mL) was evaluated for antimicrobial activity against panel of test pathogens. The antibacterial activity was measured a...

  5. A polyketide synthase-peptide synthetase gene cluster from an uncultured bacterial symbiont of Paederus beetles

    OpenAIRE

    Piel, Jörn

    2002-01-01

    Many drug candidates from marine and terrestrial invertebrates are suspected metabolites of uncultured bacterial symbionts. The antitumor polyketides of the pederin family, isolated from beetles and sponges, are an example. Drug development from such sources is commonly hampered by low yields and the difficulty of sustaining invertebrate cultures. To obtain insight into the true producer and find alternative supplies of these rare drug candidates, the putative pederin biosynthesis genes were ...

  6. HIV Transmission

    Science.gov (United States)

    ... Abroad Treatment Basic Statistics Get Tested Find an HIV testing site near you. Enter ZIP code or city Follow HIV/AIDS CDC HIV CDC HIV/AIDS See RSS | ... on HIV Syndicated Content Website Feedback HIV/AIDS HIV Transmission Language: English (US) Español (Spanish) Recommend ...

  7. Non-native acylated homoserine lactones reveal that LuxIR quorum sensing promotes symbiont stability.

    Science.gov (United States)

    Studer, Sarah V; Schwartzman, Julia A; Ho, Jessica S; Geske, Grant D; Blackwell, Helen E; Ruby, Edward G

    2014-08-01

    Quorum sensing, a group behaviour coordinated by a diffusible pheromone signal and a cognate receptor, is typical of bacteria that form symbioses with plants and animals. LuxIR-type N-acyl L-homoserine (AHL) quorum sensing is common in Gram-negative Proteobacteria, and many members of this group have additional quorum-sensing networks. The bioluminescent symbiont Vibrio fischeri encodes two AHL signal synthases: AinS and LuxI. AinS-dependent quorum sensing converges with LuxI-dependent quorum sensing at the LuxR regulatory element. Both AinS- and LuxI-mediated signalling are required for efficient and persistent colonization of the squid host, Euprymna scolopes. The basis of the mutualism is symbiont bioluminescence, which is regulated by both LuxI- and AinS-dependent quorum sensing, and is essential for maintaining a colonization of the host. Here, we used chemical and genetic approaches to probe the dynamics of LuxI- and AinS-mediated regulation of bioluminescence during symbiosis. We demonstrate that both native AHLs and non-native AHL analogues can be used to non-invasively and specifically modulate induction of symbiotic bioluminescence via LuxI-dependent quorum sensing. Our data suggest that the first day of colonization, during which symbiont bioluminescence is induced by LuxIR, is a critical period that determines the stability of the V. fischeri population once symbiosis is established.

  8. Unraveling the role of fungal symbionts in plant abiotic stress tolerance.

    Science.gov (United States)

    Singh, Lamabam Peter; Gill, Sarvajeet Singh; Tuteja, Narendra

    2011-02-01

    Fungal symbionts have been found associated with every plant studied in natural ecosystem, where they colonize and reside entirely in the internal tissues of their host plant or partially. Fungal endophytes can express/form a range of different lifestyle/relationships with different host including symbiotic, mutualistic, commensalistic and parasitic in response to host genotype and environmental factors. In mutualistic association fungal endophyte can enhance growth, increase reproductive success and confer biotic and abiotic stress tolerance to its host plant. Since abiotic stress such as, drought, high soil salinity, heat, cold, oxidative stress, heavy metal toxicity is the common adverse environmental conditions that affect and limit crop productivity worldwide. It may be a promising alternative strategy to exploit fungal endophytes to overcome the limitations to crop production brought by abiotic stress. There is increasing interest in developing the potential biotechnological applications of fungal endophytes for improving plant stress tolerance and sustainable production of food crops. Here we have described the fungal symbioses, fungal symbionts and their role in abiotic stress tolerance. A putative mechanism of stress tolerance by symbionts has also been covered.

  9. Depth specialization in mesophotic corals (Leptoseris spp.) and associated algal symbionts in Hawai'i.

    Science.gov (United States)

    Pochon, X; Forsman, Z H; Spalding, H L; Padilla-Gamiño, J L; Smith, C M; Gates, R D

    2015-02-01

    Corals at the lower limits of mesophotic habitats are likely to have unique photosynthetic adaptations that allow them to persist and dominate in these extreme low light ecosystems. We examined the host-symbiont relationships from the dominant coral genus Leptoseris in mesophotic environments from Hawai'i collected by submersibles across a depth gradient of 65-125 m. Coral and Symbiodinium genotypes were compared with three distinct molecular markers including coral (COX1-1-rRNA intron) and Symbiodinium (COI) mitochondrial markers and nuclear ITS2. The phylogenetic reconstruction clearly resolved five Leptoseris species, including one species (Leptoseris hawaiiensis) exclusively found in deeper habitats (115-125 m). The Symbiodinium mitochondrial marker resolved three unambiguous haplotypes in clade C, which were found at significantly different frequencies between host species and depths, with one haplotype exclusively found at the lower mesophotic extremes (95-125 m). These patterns of host-symbiont depth specialization indicate that there are limits to connectivity between upper and lower mesophotic zones, suggesting that niche specialization plays a critical role in host-symbiont evolution at mesophotic extremes.

  10. Impacts of Antibiotic and Bacteriophage Treatments on the Gut-Symbiont-Associated Blissus insularis (Hemiptera: Blissidae

    Directory of Open Access Journals (Sweden)

    Yao Xu

    2016-11-01

    Full Text Available The Southern chinch bug, Blissus insularis, possesses specialized midgut crypts that harbor dense populations of the exocellular symbiont Burkholderia. Oral administration of antibiotics suppressed the gut symbionts in B. insularis and negatively impacted insect host fitness, as reflected by retarded development, smaller body size, and higher susceptibility to an insecticide, bifenthrin. Considering that the antibiotics probably had non-lethal but toxic effects on host fitness, attempts were conducted to reduce gut symbionts using bacteriophage treatment. Soil-lytic phages active against the cultures of specific Burkholderia ribotypes were successfully isolated using a soil enrichment protocol. Characterization of the BiBurk16MC_R phage determined its specificity to the Bi16MC_R_vitro ribotype and placed it within the family Podoviridae. Oral administration of phages to fifth-instar B. insularis, inoculated with Bi16MC_R_vitro as neonates had no deleterious effects on host fitness. However, the ingested phages failed to impact the crypt-associated Burkholderia. The observed inactivity of the phage was likely due to the blockage of the connection between the anterior and posterior midgut regions. These findings suggest that the initial colonization by Burkholderia programs the ontogeny of the midgut, providing a sheltered residence protected from microbial antagonists.

  11. Gene expression in gut symbiotic organ of stinkbug affected by extracellular bacterial symbiont.

    Directory of Open Access Journals (Sweden)

    Ryo Futahashi

    Full Text Available The bean bug Riptortus pedestris possesses a specialized symbiotic organ in a posterior region of the midgut, where numerous crypts harbor extracellular betaproteobacterial symbionts of the genus Burkholderia. Second instar nymphs orally acquire the symbiont from the environment, and the symbiont infection benefits the host by facilitating growth and by occasionally conferring insecticide resistance. Here we performed comparative transcriptomic analyses of insect genes expressed in symbiotic and non-symbiotic regions of the midgut dissected from Burkholderia-infected and uninfected R. pedestris. Expression sequence tag analysis of cDNA libraries and quantitative reverse transcription PCR identified a number of insect genes expressed in symbiosis- or aposymbiosis-associated patterns. For example, genes up-regulated in symbiotic relative to aposymbiotic individuals, including many cysteine-rich secreted protein genes and many cathepsin protease genes, are likely to play a role in regulating the symbiosis. Conversely, genes up-regulated in aposymbiotic relative to symbiotic individuals, including a chicken-type lysozyme gene and a defensin-like protein gene, are possibly involved in regulation of non-symbiotic bacterial infections. Our study presents the first transcriptomic data on gut symbiotic organ of a stinkbug, which provides initial clues to understanding of molecular mechanisms underlying the insect-bacterium gut symbiosis and sheds light on several intriguing commonalities between endocellular and extracellular symbiotic associations.

  12. Identification and characterization of a novel porin family highlights a major difference in the outer membrane of chlamydial symbionts and pathogens.

    Directory of Open Access Journals (Sweden)

    Karin Aistleitner

    Full Text Available The Chlamydiae constitute an evolutionary well separated group of intracellular bacteria comprising important pathogens of humans as well as symbionts of protozoa. The amoeba symbiont Protochlamydia amoebophila lacks a homologue of the most abundant outer membrane protein of the Chlamydiaceae, the major outer membrane protein MOMP, highlighting a major difference between environmental chlamydiae and their pathogenic counterparts. We recently identified a novel family of putative porins encoded in the genome of P. amoebophila by in silico analysis. Two of these Protochlamydiaouter membrane proteins, PomS (pc1489 and PomT (pc1077, are highly abundant in outer membrane preparations of this organism. Here we show that all four members of this putative porin family are toxic when expressed in the heterologous host Escherichia coli. Immunofluorescence analysis using antibodies against heterologously expressed PomT and PomS purified directly from elementary bodies, respectively, demonstrated the location of both proteins in the outer membrane of P. amoebophila. The location of the most abundant protein PomS was further confirmed by immuno-transmission electron microscopy. We could show that pomS is transcribed, and the corresponding protein is present in the outer membrane throughout the complete developmental cycle, suggesting an essential role for P. amoebophila. Lipid bilayer measurements demonstrated that PomS functions as a porin with anion-selectivity and a pore size similar to the Chlamydiaceae MOMP. Taken together, our results suggest that PomS, possibly in concert with PomT and other members of this porin family, is the functional equivalent of MOMP in P. amoebophila. This work contributes to our understanding of the adaptations of symbiotic and pathogenic chlamydiae to their different eukaryotic hosts.

  13. Beneficial effect of Verminephrobacter nephridial symbionts on the fitness of the earthworm Aporrectodea tuberculata

    DEFF Research Database (Denmark)

    Lund, Marie Braad; Holmstrup, Martin; Lomstein, Bente Aagaard

    2010-01-01

    , the symbionts have been hypothesized to enhance nitrogen retention in the earthworms. The effect of Verminephrobacter on the life-history traits of the earthworm Aporrectodea tuberculata (Eisen) was investigated by comparing growth, development, and fecundity of worms with and without symbionts, given high...... (cowdung) and low (straw) nutrient diets. There were no difference in worm growth and number of cocoons produced by symbiotic and aposymbiotic worms. Worms with Verminephrobacter symbionts reached sexual maturity earlier and had higher cocoon hatching success than worms cured from their symbionts when...... grown on the low nutrient diet. Thus, the Verminephrobacter nephridial symbionts do have a beneficial effect on their earthworm host. Cocoons with and without symbionts did not significantly differ in total organic carbon (TOC), total nitrogen (TN), or total hydrolysable amino acid (THAA) content, which...

  14. The origin of the chemical profiles of fungal symbionts and their significance for nestmate recognition in Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Richard, Freddie-Jeanne; Poulsen, Michael; Hefetz, Abraham

    2007-01-01

    and evaluated the quantitative variation of the 47 compounds in a multivariate analysis. Colony-specific chemical profiles of fungal symbionts were highly distinct and significantly different between the two ant species. We also estimated the relative genetic distances between the fungal symbionts using...... in chemical profiles could be explained by genetic differences between the fungal symbionts. However, there was no significant effect of ant species in partial analyses because genetic differences between symbionts tend to coincide with being reared by different ant species. However, compound groups differed...... significantly with amides, aldehydes, and methyl esters contributing to the correlations, but acetates, alkanes, and formates being unrelated to genetic variation among symbionts. We show experimentally that workers that are previously exposed to and fed with the fungal symbiont of another colony are met...

  15. Conjugating effects of symbionts and environmental factors on gene expression in deep-sea hydrothermal vent mussels

    Directory of Open Access Journals (Sweden)

    Corre Erwan

    2011-10-01

    Full Text Available Abstract Background The deep-sea hydrothermal vent mussel Bathymodiolus azoricus harbors thiotrophic and methanotrophic symbiotic bacteria in its gills. While the symbiotic relationship between this hydrothermal mussel and these chemoautotrophic bacteria has been described, the molecular processes involved in the cross-talking between symbionts and host, in the maintenance of the symbiois, in the influence of environmental parameters on gene expression, and in transcriptome variation across individuals remain poorly understood. In an attempt to understand how, and to what extent, this double symbiosis affects host gene expression, we used a transcriptomic approach to identify genes potentially regulated by symbiont characteristics, environmental conditions or both. This study was done on mussels from two contrasting populations. Results Subtractive libraries allowed the identification of about 1000 genes putatively regulated by symbiosis and/or environmental factors. Microarray analysis showed that 120 genes (3.5% of all genes were differentially expressed between the Menez Gwen (MG and Rainbow (Rb vent fields. The total number of regulated genes in mussels harboring a high versus a low symbiont content did not differ significantly. With regard to the impact of symbiont content, only 1% of all genes were regulated by thiotrophic (SOX and methanotrophic (MOX bacteria content in MG mussels whereas 5.6% were regulated in mussels collected at Rb. MOX symbionts also impacted a higher proportion of genes than SOX in both vent fields. When host transcriptome expression was analyzed with respect to symbiont gene expression, it was related to symbiont quantity in each field. Conclusions Our study has produced a preliminary description of a transcriptomic response in a hydrothermal vent mussel host of both thiotrophic and methanotrophic symbiotic bacteria. This model can help to identify genes involved in the maintenance of symbiosis or regulated by

  16. Growth and Transfer of Monolithic Horizontal ZnO Nanowire Superstructures onto Flexible Substrates

    KAUST Repository

    Xu, Sheng

    2010-04-28

    A method of fabricating horizontally aligned ZnO nanowire (NW) arrays with full control over the width and length is demonstrated. A cross-sectional view of the NWs by transmission electron microscopy shows a "mushroom-like" structure. Novel monolithic multisegment superstructures are fabricated by making use of the lateral overgrowth. Ultralong horizontal ZnO NWs of an aspect ratio on the order often thousand are also demonstrated. These horizontal NWs are lifted off and transferred onto a flexible polymer substrate, which may have many great applications in horizontal ZnO NW-based nanosensor arrays, light-emitting diodes, optical gratings, integrated circuit interconnects, and high-output-power alternating-current nanogenerators. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA.

  17. Phylogenetic relationships of chemoautotrophic bacterial symbionts of Solemya velum say (Mollusca: Bivalvia) determined by 16S rRNA gene sequence analysis.

    OpenAIRE

    Eisen, J. A.; Smith, S W; Cavanaugh, Colleen Marie

    1992-01-01

    The protobranch bivalve Solemya velum Say (Mollusca: Bivalvia) houses chemoautotrophic symbionts intracellularly within its gills. These symbionts were characterized through sequencing of polymerase chain reaction-amplified 16S rRNA coding regions and hybridization of an Escherichia coli gene probe to S. velum genomic DNA restriction fragments. The symbionts appeared to have only one copy of the 16S rRNA gene. The lack of variability in the 16S sequence and hybridization patterns within and b...

  18. Widespread horizontal transfer of retrotransposons.

    Science.gov (United States)

    Walsh, Ali Morton; Kortschak, R Daniel; Gardner, Michael G; Bertozzi, Terry; Adelson, David L

    2013-01-15

    In higher organisms such as vertebrates, it is generally believed that lateral transfer of genetic information does not readily occur, with the exception of retroviral infection. However, horizontal transfer (HT) of protein coding repetitive elements is the simplest way to explain the patchy distribution of BovB, a long interspersed element (LINE) about 3.2 kb long, that has been found in ruminants, marsupials, squamates, monotremes, and African mammals. BovB sequences are a major component of some of these genomes. Here we show that HT of BovB is significantly more widespread than believed, and we demonstrate the existence of two plausible arthropod vectors, specifically reptile ticks. A phylogenetic tree built from BovB sequences from species in all of these groups does not conform to expected evolutionary relationships of the species, and our analysis indicates that at least nine HT events are required to explain the observed topology. Our results provide compelling evidence for HT of genetic material that has transformed vertebrate genomes.

  19. On the Hydraulics of Flowing Horizontal Wells

    Science.gov (United States)

    Bian, A.; Zhan, H.

    2003-12-01

    A flowing horizontal well is a special type of horizontal well that does not have pumping/injecting facility. The discharge rate of a flowing horizontal well is controlled by the hydraulic gradient between the aquifer and the well and it generally varies with time if the hydraulic head of the aquifer is transient. This type of well has been used in landslide control, mining dewatering, water table control, underground water transportation through a horizontal tunnel, agricultural water drainage, and other applications. Flowing horizontal wells have quite different hydrodynamic characteristics from horizontal wells with fixed pumping or injecting rates because their discharge rates are functions of the aquifer hydraulic heads (Zhan et al, 2001; Zhan and Zlotnik, 2002). Hydraulics of flowing horizontal wells have rarely been studied although the hydraulics of flowing vertical wells have been extensively investigated before. The purpose of this paper is to obtain analytical solutions of groundwater flow to a flowing horizontal-well in a confined aquifer, in a water table aquifer without precipitation, and in a water table aquifer with precipitation. The functions of the flowing horizontal well discharge rates versus time will be obtained under above mentioned different aquifer conditions. The relationships of the aquifer hydraulic heads versus the discharge rates of the well will be investigated. The rate of water table decline due to the dewatering of the well will also be computed, and this solution is particularly useful for landslide control and mining dewatering. The theoretical solutions will be compared with results of experiments that will be conducted in the hydrological laboratory at Texas A&M University. Reference: Zhan, H., Wang, L.V., and Park, E, On the horizontal well pumping tests in the anisotropic confined aquifers, J. hydrol., 252, 37-50, 2001. Zhan, H., and Zlotnik, V. A., Groundwater flow to a horizontal or slanted well in an unconfined aquifer

  20. Comparative Profiling of coral symbiont communities from the Caribbean, Indo-Pacific, and Arabian Seas

    KAUST Repository

    Arif, Chatchanit

    2014-12-01

    Coral reef ecosystems are in rapid decline due to global and local anthropogenic factors. Being among the most diverse ecosystems on Earth, a loss will decrease species diversity, and remove food source for people along the coast. The coral together with its symbionts (i.e. Symbiodinium, bacteria, and other microorganisms) is called the ‘coral holobiont’. The coral host offers its associated symbionts suitable habitats and nutrients, while Symbiodinium and coral-associated bacteria provide the host with photosynthates and vital nutrients. Association of corals with certain types of Symbiodinium and bacteria confer coral stress tolerance, and lack or loss of these symbionts coincides with diseased or bleached corals. However, a detailed understanding of the coral holobiont diversity and structure in regard to diseases and health states or across global scales is missing. This dissertation addressed coral-associated symbiont diversity, specifically of Symbiodinium and bacteria, in various coral species from different geographic locations and different health states. The main aims were (1) to expand the scope of existing technologies, (2) to establish a standardized framework to facilitate comparison of symbiont assemblages over coral species and sites, (3) to assess Symbiodinium diversity in the Arabian Seas, and (4) to elucidate whether coral health states have conserved bacterial footprints. In summary, a next generation sequencing pipeline for Symbiodinium diversity typing of the ITS2 marker is developed and applied to describe Symbiodinium diversity in corals around the Arabian Peninsula. The data show that corals in the Arabian Seas are dominated by a single Symbiodinium type, but harbor a rich variety of types in low abundant. Further, association with different Symbiodinium types is structured according to geographic locations. In addition, the application of 16S rRNA gene microarrays to investigate how differences in microbiome structure relate to

  1. A journey into the wild of the cnidarian model system Aiptasia and its symbionts

    KAUST Repository

    Voolstra, Christian R.

    2013-08-27

    The existence of coral reef ecosystems relies critically on the mutualistic relationship between calcifying cnidarians and photosynthetic, dinoflagellate endosymbionts in the genus Symbiodinium. Reef-corals have declined globally due to anthropogenic stressors, for example, rising sea-surface temperatures and pollution that often disrupt these symbiotic relationships (known as coral bleaching), exacerbating mass mortality and the spread of disease. This threatens one of the most biodiverse marine ecosystems providing habitats to millions of species and supporting an estimated 500 million people globally (Hoegh-Guldberg et al. 2007). Our understanding of cnidarian-dinoflagellate symbioses has improved notably with the recent application of genomic and transcriptomic tools (e.g. Voolstra et al. 2009; Bayer et al. 2012; Davy et al. 2012), but a model system that allows for easy manipulation in a laboratory environment is needed to decipher underlying cellular mechanisms important to the functioning of these symbioses. To this end, the sea anemone Aiptasia, otherwise known as a \\'pest\\' to aquarium hobbyists, is emerging as such a model system (Schoenberg & Trench 1980; Sunagawa et al. 2009; Lehnert et al. 2012). Aiptasia is easy to grow in culture and, in contrast to its stony relatives, can be maintained aposymbiotically (i.e. dinoflagellate free) with regular feeding. However, we lack basic information on the natural distribution and genetic diversity of these anemones and their endosymbiotic dinoflagellates. These data are essential for placing the significance of this model system into an ecological context. In this issue of Molecular Ecology, Thornhill et al. (2013) are the first to present genetic evidence on the global distribution, diversity and population structure of Aiptasia and its associated Symbiodinium spp. By integrating analyses of the host and symbiont, this research concludes that the current Aitpasia taxonomy probably needs revision and that two

  2. Horizontal Directional Drilling (HDD) Technology and Applications

    Institute of Scientific and Technical Information of China (English)

    J. G. Cai; X. N. Wang

    2004-01-01

    @@ 1 What is Horizontal Directional Drilling? Horizontal Directional Drilling, accurately steered drilling, has become state -of- the -art drilling technique in the world. Specially- designed directionsteerable corebarrel and accurate direction measurement tool are available for the use together with wire line core drilling machine. That makes it feasible to extract cores and to measure the drill travel line &length while drilling in a curve.

  3. Infectious speciation revisited: impact of symbiont-depletion on female fitness and mating behavior of Drosophila paulistorum.

    Directory of Open Access Journals (Sweden)

    Wolfgang J Miller

    2010-12-01

    Full Text Available The neotropical Drosophila paulistorum superspecies, consisting of at least six geographically overlapping but reproductively isolated semispecies, has been the object of extensive research since at least 1955, when it was initially trapped mid-evolution in flagrant statu nascendi. In this classic system females express strong premating isolation patterns against mates belonging to any other semispecies, and yet uncharacterized microbial reproductive tract symbionts were described triggering hybrid inviability and male sterility. Based on theoretical models and limited experimental data, prime candidates fostering symbiont-driven speciation in arthropods are intracellular bacteria belonging to the genus Wolbachia. They are maternally inherited symbionts of many arthropods capable of manipulating host reproductive biology for their own benefits. However, it is an ongoing debate as to whether or not reproductive symbionts are capable of driving host speciation in nature and if so, to what extent. Here we have reevaluated this classic case of infectious speciation by means of present day molecular approaches and artificial symbiont depletion experiments. We have isolated the α-proteobacteria Wolbachia as the maternally transmitted core endosymbionts of all D. paulistorum semispecies that have coevolved towards obligate mutualism with their respective native hosts. In hybrids, however, these mutualists transform into pathogens by overreplication causing embryonic inviability and male sterility. We show that experimental reduction in native Wolbachia titer causes alterations in sex ratio, fecundity, and mate discrimination. Our results indicate that formerly designated Mycoplasma-like organisms are most likely Wolbachia that have evolved by becoming essential mutualistic symbionts in their respective natural hosts; they have the potential to trigger pre- and postmating isolation. Furthermore, in light of our new findings, we revisit the concept of

  4. Robot Vibrations Caused by Torque Ripples in Power Transmission Mechanisms

    OpenAIRE

    小島, 宏行; 田口, 和哉; 辻, 浩明

    1989-01-01

    When an industrial robot with a power transmission mechanism such as a harmonic drive gear is operated, vibrations resulting from the torque ripple of the power transmission mechanism are frequently generated. However, few studies on robot vibration characteristics owing to torque ripples have been reported. In this paper, the vibrations of a horizontal two-link robot are investigated with consideration given to the torque ripple and the nonlinearity of the power transmission mechanism. In th...

  5. Intra-firm Horizontal Knowledge Transfer Management

    Institute of Scientific and Technical Information of China (English)

    WANG Yaowu; WANG Yanhang

    2009-01-01

    Knowledge transfer is widely emphasized as a strategic issue for firm competition. A model for intra-firm horizontal knowledge transfer is proposed to model horizontal knowledge transfer to solve some demerits in current knowledge transfer researches. The concept model of intra-firm horizontal knowledge transfer was described and a framework was provided to define the main components of thetransfer process. Horizontal knowledge transfer is that knowledge is transferred from the source to the same hierarchical level recipients as the target. Horizontal knowledge transfer constitutes a strategic area of knowledge management research. However, little is known about the circumstances under which one particular mechanism is the most appropriate. To address these issues, some significant conclusions are drawn concerning knowledge transfer mechanisms in a real-world setting.

  6. Horizontal Canal Benign Positional Vertigo

    Directory of Open Access Journals (Sweden)

    Mohtaram Najafi

    1998-03-01

    Full Text Available Benign paroxysmal positional vertigo (BPPV is a syndrome characterized by transient episodes of vertigo in association with rapid changes in head position in Dix-Halpike Maneuver. This kind of vertigo is thought to be caused by migration of otoconial debris into canals other than the posterior canal, such as the anterior or lateral canals. It is also theoretically possible for many aberrant patterns of BPPV to occur from an interaction of debris in several canals, location of debris within the canal, and central adaptation patterns to lesions. The symptoms of BPPV are much more consistent with free-moving densities (canaliths in the posterior SCC rather than fixed densities attached to the cupula. While the head is upright, the particles sit in the PSC at the most gravity-dependent position. The best method to induce and see vertigo and nystagmus in BPPV of the lateral semicircular canal is to rotate head 90°while patient is in the supine position, nystagmus would appear in the unaffected side weaker but longer than the affected side. canal paresis has been described in one third of the patients with BPPV. Adaptation which is one of the remarkable features of BPPV in PSC is rarely seen in LSC. Rotations of 270° or 360° around the yaw axis (the so-called barbecue maneuver toward the unaffected ear are popular methods for the treatment of geotropic HC-BPPV. These maneuvers consist of sequential head turning of 90° toward the healthy side while supine. With these maneuvers, the free-floating otoconial debris migrates in the ampullofugal direction, finally entering the utricle through the nonampullated end of the horizontal canal. This kind of vertigo recovers spontaneously more rapidly and suddenly.

  7. Unexpected co-occurrence of six bacterial symbionts in the gills of the cold seep mussel Idas sp. (Bivalvia: Mytilidae).

    Science.gov (United States)

    Duperron, Sébastien; Halary, Sébastien; Lorion, Julien; Sibuet, Myriam; Gaill, Françoise

    2008-02-01

    Bathymodioline mussels occur in chemosynthesis-based ecosystems such as cold seeps, hydrothermal vents and organic debris worldwide. Their key adaptation to these environments is their association with bacterial endosymbionts which ensure a chemosynthetic primary production based on the oxidation of reduced compounds such as methane and sulfide. We herein report a multiple symbiosis involving six distinct bacterial 16S rRNA phylotypes, including two belonging to groups not yet reported as symbionts in mytilids, in a small Idas mussel found on carbonate crusts in a cold seep area located north to the Nile deep-sea fan (Eastern Mediterranean). Symbionts co-occur within hosts bacteriocytes based on fluorescence in situ hybridizations, and sequencing of functional genes suggests they have the potential to perform autotrophy, and sulfide and methane oxidation. Previous studies indicated the presence of only one or two symbiont 16S rRNA phylotypes in bathymodioline mussels. Together with the recent discovery of four bacterial symbionts in the large seep species Bathymodiolus heckerae, this study shows that symbiont diversity has probably been underestimated, and questions whether the common ancestor of bathymodioline mussels was associated with multiple bacteria.

  8. Optimizing of Culture Conditionin Horizontal Rotating Bioreactor

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    1 IntroductionBioreactor is the most important equipment in tissue engineering. It can mimic the micro-environment of cell growth in vitro. At present, horizontal rotating bioreactor is the most advanced equipment for cell culture in the world. 2 Rotating bioreactors2.1 Working principleThere are two kinds of horizontal rotating bioreactor: HARV(high aspect ratio vessel) and RCCS (rotary cell culture system). It is drived by step motor with horizontal rotation, the culture medium and cell is filled between ...

  9. Horizontal gene transfer and bacterial diversity

    Indian Academy of Sciences (India)

    Chitra Dutta; Archana Pan

    2002-02-01

    Bacterial genomes are extremely dynamic and mosaic in nature. A substantial amount of genetic information is inserted into or deleted from such genomes through the process of horizontal transfer. Through the introduction of novel physiological traits from distantly related organisms, horizontal gene transfer often causes drastic changes in the ecological and pathogenic character of bacterial species and thereby promotes microbial diversification and speciation. This review discusses how the recent influx of complete chromosomal sequences of various microorganisms has allowed for a quantitative assessment of the scope, rate and impact of horizontally transmitted information on microbial evolution.

  10. Large shift in symbiont assemblage in the invasive red turpentine beetle.

    Science.gov (United States)

    Taerum, Stephen J; Duong, Tuan A; de Beer, Z Wilhelm; Gillette, Nancy; Sun, Jiang-Hua; Owen, Donald R; Wingfield, Michael J

    2013-01-01

    Changes in symbiont assemblages can affect the success and impact of invasive species, and may provide knowledge regarding the invasion histories of their vectors. Bark beetle symbioses are ideal systems to study changes in symbiont assemblages resulting from invasions. The red turpentine beetle (Dendroctonus valens) is a bark beetle species that recently invaded China from its native range in North America. It is associated with ophiostomatalean fungi in both locations, although the fungi have previously been well-surveyed only in China. We surveyed the ophiostomatalean fungi associated with D. valens in eastern and western North America, and identified the fungal species using multi-gene phylogenies. From the 307 collected isolates (147 in eastern North America and 160 in western North America), we identified 20 species: 11 in eastern North America and 13 in western North America. Four species were shared between eastern North America and western North America, one species (Ophiostoma floccosum) was shared between western North America and China, and three species (Grosmannia koreana, Leptographium procerum, and Ophiostoma abietinum) were shared between eastern North America and China. Ophiostoma floccosum and O. abietinum have worldwide distributions, and were rarely isolated from D. valens. However, G. koreana and L. procerum are primarily limited to Asia and North America respectively. Leptographium procerum, which is thought to be native to North America, represented >45% of the symbionts of D. valens in eastern North America and China, suggesting D. valens may have been introduced to China from eastern North America. These results are surprising, as previous population genetics studies on D. valens based on the cytochrome oxidase I gene have suggested that the insect was introduced into China from western North America.

  11. Molecular evidence for Lessepsian invasion of soritids (larger symbiont bearing benthic foraminifera.

    Directory of Open Access Journals (Sweden)

    Gily Merkado

    Full Text Available The Mediterranean Sea is considered as one of the hotspots of marine bioinvasions, largely due to the influx of tropical species migrating through the Suez Canal, so-called Lessepsian migrants. Several cases of Lessepsian migration have been documented recently, however, little is known about the ecological characteristics of the migrating species and their aptitude to colonize the new areas. This study focused on Red Sea soritids, larger symbiont-bearing benthic foraminifera (LBF that are indicative of tropical and subtropical environments and were recently found in the Israeli coast of the Eastern Mediterranean. We combined molecular phylogenetic analyses of soritids and their algal symbionts as well as network analysis of Sorites orbiculus Forskål to compare populations from the Gulf of Elat (northern Red Sea and from a known hotspot in Shikmona (northern Israel that consists of a single population of S. orbiculus. Our phylogenetic analyses show that all specimens found in Shikmona are genetically identical to a population of S. orbiculus living on a similar shallow water pebbles habitat in the Gulf of Elat. Our analyses also show that the symbionts found in Shikmona and Elat soritids belong to the Symbiodinium clade F5, which is common in the Red Sea and also present in the Indian Ocean and Caribbean Sea. Our study therefore provides the first genetic and ecological evidences that indicate that modern population of soritids found on the Mediterranean coast of Israel is probably Lessepsian, and is less likely the descendant of a native ancient Mediterranean species.

  12. Dark production of extracellular superoxide by the coral Porites astreoides and representative symbionts

    Directory of Open Access Journals (Sweden)

    Tong Zhang

    2016-11-01

    Full Text Available The reactive oxygen species (ROS superoxide has been implicated in both beneficial and detrimental processes in coral biology, ranging from pathogenic disease resistance to coral bleaching. Despite the critical role of ROS in coral health, there is a distinct lack of ROS measurements and thus an incomplete understanding of underpinning ROS sources and production mechanisms within coral systems. Here, we quantified in situ extracellular superoxide concentrations at the surfaces of aquaria-hosted Porites astreoides during a diel cycle. High concentrations of superoxide (~10’s of nM were present at coral surfaces, and these levels did not change significantly as a function of time of day. These results indicate that the coral holobiont produces extracellular superoxide in the dark, independent of photosynthesis. As a short-lived anion at physiological pH, superoxide has a limited ability to cross intact biological membranes. Further, removing surface mucus layers from the P. astreoides colonies did not impact external superoxide concentrations. We therefore attribute external superoxide derived from the coral holobiont under these conditions to the activity of the coral host epithelium, rather than mucus-derived epibionts or internal sources such as endosymbionts (e.g., Symbiodinium. However, endosymbionts likely contribute to internal ROS levels via extracellular superoxide production. Indeed, common coral symbionts, including multiple strains of Symbiodinium (clades A to D and the bacterium Endozoicomonas montiporae LMG 24815, produced extracellular superoxide in the dark and at low light levels. Further, representative P. astreoides symbionts, Symbiodinium CCMP2456 (clade A and E. montiporae, produced similar concentrations of superoxide alone and in combination with each other, in the dark and low light, and regardless of time of day. Overall, these results indicate that healthy, non-stressed P. astreoides and representative symbionts produce

  13. Endophytic life strategies decoded by genome and transcriptome analyses of the mutualistic root symbiont Piriformospora indica.

    Directory of Open Access Journals (Sweden)

    Alga Zuccaro

    2011-10-01

    Full Text Available Recent sequencing projects have provided deep insight into fungal lifestyle-associated genomic adaptations. Here we report on the 25 Mb genome of the mutualistic root symbiont Piriformospora indica (Sebacinales, Basidiomycota and provide a global characterization of fungal transcriptional responses associated with the colonization of living and dead barley roots. Extensive comparative analysis of the P. indica genome with other Basidiomycota and Ascomycota fungi that have diverse lifestyle strategies identified features typically associated with both, biotrophism and saprotrophism. The tightly controlled expression of the lifestyle-associated gene sets during the onset of the symbiosis, revealed by microarray analysis, argues for a biphasic root colonization strategy of P. indica. This is supported by a cytological study that shows an early biotrophic growth followed by a cell death-associated phase. About 10% of the fungal genes induced during the biotrophic colonization encoded putative small secreted proteins (SSP, including several lectin-like proteins and members of a P. indica-specific gene family (DELD with a conserved novel seven-amino acids motif at the C-terminus. Similar to effectors found in other filamentous organisms, the occurrence of the DELDs correlated with the presence of transposable elements in gene-poor repeat-rich regions of the genome. This is the first in depth genomic study describing a mutualistic symbiont with a biphasic lifestyle. Our findings provide a significant advance in understanding development of biotrophic plant symbionts and suggest a series of incremental shifts along the continuum from saprotrophy towards biotrophy in the evolution of mycorrhizal association from decomposer fungi.

  14. Large shift in symbiont assemblage in the invasive red turpentine beetle.

    Directory of Open Access Journals (Sweden)

    Stephen J Taerum

    Full Text Available Changes in symbiont assemblages can affect the success and impact of invasive species, and may provide knowledge regarding the invasion histories of their vectors. Bark beetle symbioses are ideal systems to study changes in symbiont assemblages resulting from invasions. The red turpentine beetle (Dendroctonus valens is a bark beetle species that recently invaded China from its native range in North America. It is associated with ophiostomatalean fungi in both locations, although the fungi have previously been well-surveyed only in China. We surveyed the ophiostomatalean fungi associated with D. valens in eastern and western North America, and identified the fungal species using multi-gene phylogenies. From the 307 collected isolates (147 in eastern North America and 160 in western North America, we identified 20 species: 11 in eastern North America and 13 in western North America. Four species were shared between eastern North America and western North America, one species (Ophiostoma floccosum was shared between western North America and China, and three species (Grosmannia koreana, Leptographium procerum, and Ophiostoma abietinum were shared between eastern North America and China. Ophiostoma floccosum and O. abietinum have worldwide distributions, and were rarely isolated from D. valens. However, G. koreana and L. procerum are primarily limited to Asia and North America respectively. Leptographium procerum, which is thought to be native to North America, represented >45% of the symbionts of D. valens in eastern North America and China, suggesting D. valens may have been introduced to China from eastern North America. These results are surprising, as previous population genetics studies on D. valens based on the cytochrome oxidase I gene have suggested that the insect was introduced into China from western North America.

  15. Horizontal cooperation in transport and logistics

    NARCIS (Netherlands)

    Cruijssen, F.C.A.M.

    2006-01-01

    This thesis deals with horizontal cooperation in transport and logistics. It contains a comprehensive discussion of the available academic literature on this topic, many practical examples, and an empirical investigation of opportunities and impediments. Furthermore, three enabling concepts for

  16. In situ photobiology of corals over large depth ranges: A multivariate analysis on the roles of environment, host, and algal symbiont

    NARCIS (Netherlands)

    Frade, P.R.; Bongaerts, P.; Winkelhagen, A.J.S.; Tonk, L.; Bak, R.P.M.

    2008-01-01

    We applied a multivariate analysis to investigate the roles of host and symbiont on the in situ physiological response of genus Madracis holobionts towards light. Across a large depth gradient (5-40 m) and for four Madracis species and three symbiont genotypes, we assessed several variables by

  17. Draft Genome Sequence of Rhizobium mesoamericanum STM3625, a Nitrogen-Fixing Symbiont of Mimosa pudica Isolated in French Guiana (South America).

    Science.gov (United States)

    Moulin, Lionel; Mornico, Damien; Melkonian, Rémy; Klonowska, Agnieszka

    2013-01-01

    Rhizobium mesoamericanum STM3625 is a Mimosa pudica symbiont isolated in French Guiana. This strain serves as a model bacterium for comparison of adaptation to mutualism (symbiotic traits, bacterial genetic programs for plant infection) between alpha and beta rhizobial symbionts of Mimosa pudica.

  18. The pink shrimp Farfantepenaeus duorarum, its symbionts and helminths as bioindicators of chemical pollution in Campeche Sound, Mexico.

    Science.gov (United States)

    Vidal-Martínez, V M; Aguirre-Macedo, M L; Del Rio-Rodríguez, R; Gold-Bouchot, G; Rendón-von Osten, J; Miranda-Rosas, G A

    2006-06-01

    The pink shrimp Farfantepenaeus duorarum may acquire pollutants, helminths and symbionts from their environment. Statistical associations were studied between the symbionts and helminths of F. duorarum and pollutants in sediments, water and shrimps in Campeche Sound, Mexico. The study area spatially overlapped between offshore oil platforms and natural shrimp mating grounds. Spatial autocorrelation of data was controlled with spatial analysis using distance indices (SADIE) which identifies parasite or pollutant patches (high levels) and gaps (low levels), expressing them as clustering indices compared at each point to produce a measure of spatial association. Symbionts included the peritrich ciliates Epistylis sp. and Zoothamnium penaei and all symbionts were pooled. Helminths included Hysterothylacium sp., Opecoeloides fimbriatus, Prochristianella penaei and an unidentified cestode. Thirty-five pollutants were identified, including polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), pesticides and heavy metals. The PAHs (2-3 ring) in water, unresolved complex mixture (UCM), Ni and V in sediments, and Zn, Cr and heptachlor in shrimps were significantly clustered. The remaining pollutants were randomly distributed in the study area. Juvenile shrimps acquired pesticides, PAHs (2-3 rings) and Zn, while adults acquired PAHs (4-5 rings), Cu and V. Results suggest natural PAH spillovers, and continental runoff of dichlorodiphenyltrichloroethane (DDT), PCBs and PAHs (2-3 ring). There were no significant associations between pollutants and helminths. However, there were significant negative associations of pesticides, UCM and PCBs with symbiont numbers after controlling shrimp size and spatial autocorrelation. Shrimps and their symbionts appear to be promising bioindicators of organic chemical pollution in Campeche Sound.

  19. Evaluation of extremely small horizontal emittance

    Directory of Open Access Journals (Sweden)

    T. Okugi

    1999-02-01

    Full Text Available The KEK Accelerator Test Facility (KEK-ATF was constructed to develop technologies for producing a low-emittance beam which will be required by future linear colliders. The KEK-ATF consists of an injector linac, a damping ring, and a beam extraction line. The basic optical structure of the damping ring is a FOBO lattice, which reduces the horizontal dispersion at the center of the bending magnets and, as a consequence, can produce an extremely small emittance beam. To verify the performance of such a unique, low-emittance lattice, it is crucial to measure the horizontal emittance. The horizontal emittance was measured using wire scanners in the beam extraction line. Since the horizontal beam position was not stable, we established a method to correct the measured beam size for position fluctuation (“jitter” and we succeeded in the observation of the so far smallest horizontal emittance in any accelerator. The measured horizontal emittance was 1.37±0.03nm at a beam energy of 1.285 GeV and a bunch population of \\(3–5\\×10^{9}, in agreement with the design value of 1.27–1.34 nm at the beam energy and the bunch population.

  20. Change in algal symbiont communities after bleaching, not prior heat exposure, increases heat tolerance of reef corals.

    Science.gov (United States)

    Silverstein, Rachel N; Cunning, Ross; Baker, Andrew C

    2015-01-01

    Mutualistic organisms can be particularly susceptible to climate change stress, as their survivorship is often limited by the most vulnerable partner. However, symbiotic plasticity can also help organisms in changing environments by expanding their realized niche space. Coral-algal (Symbiodinium spp.) symbiosis exemplifies this dichotomy: the partnership is highly susceptible to 'bleaching' (stress-induced symbiosis breakdown), but stress-tolerant symbionts can also sometimes mitigate bleaching. Here, we investigate the role of diverse and mutable symbiotic partnerships in increasing corals' ability to thrive in high temperature conditions. We conducted repeat bleaching and recovery experiments on the coral Montastraea cavernosa, and used quantitative PCR and chlorophyll fluorometry to assess the structure and function of Symbiodinium communities within coral hosts. During an initial heat exposure (32 °C for 10 days), corals hosting only stress-sensitive symbionts (Symbiodinium C3) bleached, but recovered (at either 24 °C or 29 °C) with predominantly (>90%) stress-tolerant symbionts (Symbiodinium D1a), which were not detected before bleaching (either due to absence or extreme low abundance). When a second heat stress (also 32 °C for 10 days) was applied 3 months later, corals that previously bleached and were now dominated by D1a Symbiodinium experienced less photodamage and symbiont loss compared to control corals that had not been previously bleached, and were therefore still dominated by Symbiodinium C3. Additional corals that were initially bleached without heat by a herbicide (DCMU, at 24 °C) also recovered predominantly with D1a symbionts, and similarly lost fewer symbionts during subsequent thermal stress. Increased thermotolerance was also not observed in C3-dominated corals that were acclimated for 3 months to warmer temperatures (29 °C) before heat stress. These findings indicate that increased thermotolerance post-bleaching resulted from

  1. Ecoepidemiologia e Controle da Leishmaniose Visceral no município de Belo Horizonte (Minas Gerais, Brasil)

    OpenAIRE

    Fabiana Oliveira Lara e Silva

    2015-01-01

    Este estudo foi realizado em Belo Horizonte (Minas Gerais, Brasil), área endêmica para Leishmaniose visceral (LV), onde a doença vem se expandindo rapidamente, com 1.612 casos registrados nos últimos 10 anos. Nossa pesquisa avaliou o perfil epidemiológico em duas Áreas de abrangência (AA) dos Centros de Saúde (CS) Miramar e Salgado Filho do município de Belo Horizonte, com transmissão recente de LV, buscando compreender a tríade envolvida na transmissão: parasito-vetor-reservatório. ...

  2. Phylogenetic relationships of chemoautotrophic bacterial symbionts of Solemya velum say (Mollusca: Bivalvia) determined by 16S rRNA gene sequence analysis.

    Science.gov (United States)

    Eisen, J A; Smith, S W; Cavanaugh, C M

    1992-05-01

    The protobranch bivalve Solemya velum Say (Mollusca: Bivalvia) houses chemoautotrophic symbionts intracellularly within its gills. These symbionts were characterized through sequencing of polymerase chain reaction-amplified 16S rRNA coding regions and hybridization of an Escherichia coli gene probe to S. velum genomic DNA restriction fragments. The symbionts appeared to have only one copy of the 16S rRNA gene. The lack of variability in the 16S sequence and hybridization patterns within and between individual S. velum organisms suggested that one species of symbiont is dominant within and specific for this host species. Phylogenetic analysis of the 16S sequences of the symbionts indicates that they lie within the chemoautotrophic cluster of the gamma subdivision of the eubacterial group Proteobacteria.

  3. DNA adenine methylation of sams1 gene in symbiont-bearing Amoeba proteus.

    Science.gov (United States)

    Jeon, Taeck J

    2008-10-01

    The expression of amoeba sams genes is switched from sams1 to sams2 when amoebae are infected with Legionella jeonii. To elucidate the mechanism for the inactivation of host sams1 gene by endosymbiotic bacteria, methylation states of the sams1 gene of D and xD amoebae was compared in this study. The sams1 gene of amoebae was methylated at an internal adenine residue of GATC site in symbiont-bearing xD amoebae but not in symbiont-free D amoebae, suggesting that the modification might have caused the inactivation of sams1 in xD amoebae. The sams1 gene of xD amoebae was inactivated at the transcriptional level. Analysis of DNA showed that adenine residues in L. jeonii sams were also methylated, implying that L. jeonii bacteria belong to a Dam methylase-positive strain. In addition, both SAM and Met appeared to act as negative regulators for the expression of sams1 whereas the expression of sams2 was not affected in amoebae.

  4. Conditional Reduction of Predation Risk Associated with a Facultative Symbiont in an Insect.

    Directory of Open Access Journals (Sweden)

    Sarah Polin

    Full Text Available Symbionts are widespread among eukaryotes and their impacts on the ecology and evolution of their hosts are meaningful. Most insects harbour obligate and facultative symbiotic bacteria that can influence their phenotype. In the pea aphid Acyrthosiphon pisum, an astounding symbiotic-mediated phenotype has been recently observed: when infected with the symbiotic bacteria Rickettsiella viridis, young red aphid larvae become greener at adulthood and even darker green when co-infected with Rickettsiella viridis and Hamiltonella defensa. As body colour affects the susceptibility towards natural enemies in aphids, the influence of the colour change due to these facultative symbionts on the host survival in presence of predators was tested. Our results suggested that the Rickettsiella viridis infection may impact positively host survival by reducing predation risk. Due to results from uninfected aphids (i.e., more green ones attacked, the main assumption is that this symbiotic infection would deter the predatory ladybird feeding by reducing the profitability of their hosts rather than decreasing host detection through body colour change. Aphids co-infected with Rickettsiella viridis and Hamiltonella defensa were, however, more exposed to predation suggesting an ecological cost associated with multiple infections. The underlying mechanisms and ecological consequences of these symbiotic effects are discussed.

  5. Prevalence and distribution of three protozoan symbionts in blue crab (Callinectes sapidus) populations across Louisiana, USA.

    Science.gov (United States)

    Rogers, Holly A; Taylor, Sabrina S; Hawke, John P; Anderson Lively, Julie A

    2015-05-11

    Louisiana has one of the largest blue crab (Callinectes sapidus) fisheries in the USA, but little is known about blue crab diseases, parasites, and symbionts in this area. In 2013-2014, large juvenile and adult blue crabs were collected at 4 diverse sites to determine the prevalence of the protozoan symbionts associated with black gill disease (Lagenophrys callinectes), buckshot crabs (Urosporidium crescens), and bitter crab disease (Hematodinium perezi). A high aggregate prevalence of L. callinectes (93.2%) was identified across all seasons at all 4 collection sites regardless of salinity. A moderately low aggregate prevalence of U. crescens (22.4%) was identified across all seasons and sites. Prevalence of U. crescens depended on site salinity, with only 10% of infections detected at sites with callinectes and U. crescens are commensal parasites of blue crabs, infections can result in unmarketable and unappealing meat. In the Louisiana fishery, H. perezi has been blamed circumstantially for adult mortalities in the low salinity nearshore fishing grounds. Despite this, H. perezi was not detected in any of the large crabs sampled, even from the low salinity sites. The prevalence data reported here for these 3 protozoans are the first to include blue crabs sampled seasonally at multiple locations along the Louisiana coast over the period of a year.

  6. Building the crops of tomorrow: advantages of symbiont-based approaches to improving abiotic stress tolerance

    Directory of Open Access Journals (Sweden)

    Devin eColeman-Derr

    2014-06-01

    Full Text Available The exponential growth in world population is feeding a steadily increasing global need for arable farmland, a resource that is already in high demand. This trend has led to increased farming on subprime arid and semi-arid lands, where limited availability of water and a host of environmental stresses often severely reduce crop productivity. The conventional approach to mitigating the abiotic stresses associated with arid climes is to breed for stress-tolerant cultivars, a time and labor intensive venture that often neglects the complex ecological context of the soil environment in which the crop is grown. In recent years, studies have attempted to identify microbial symbionts capable of conferring the same stress-tolerance to their plant hosts, and new developments in genomic technologies have greatly facilitated such research. Here, we highlight many of the advantages of these symbiont-based approaches and argue in favor of the broader recognition of crop species as ecological niches for a diverse community of microorganisms that function in concert with their plant hosts and each other to thrive under fluctuating environmental conditions.

  7. Independent Effects of a Herbivore's Bacterial Symbionts on Its Performance and Induced Plant Defences.

    Science.gov (United States)

    Staudacher, Heike; Schimmel, Bernardus C J; Lamers, Mart M; Wybouw, Nicky; Groot, Astrid T; Kant, Merijn R

    2017-01-18

    It is well known that microbial pathogens and herbivores elicit defence responses in plants. Moreover, microorganisms associated with herbivores, such as bacteria or viruses, can modulate the plant's response to herbivores. Herbivorous spider mites can harbour different species of bacterial symbionts and exert a broad range of effects on host-plant defences. Hence, we tested the extent to which such symbionts affect the plant's defences induced by their mite host and assessed if this translates into changes in plant resistance. We assessed the bacterial communities of two strains of the common mite pest Tetranychus urticae. We found that these strains harboured distinct symbiotic bacteria and removed these using antibiotics. Subsequently, we tested to which extent mites with and without symbiotic bacteria induce plant defences in terms of phytohormone accumulation and defence gene expression, and assessed mite oviposition and survival as a measure for plant resistance. We observed that the absence/presence of these bacteria altered distinct plant defence parameters and affected mite performance but we did not find indications for a causal link between the two. We argue that although bacteria-related effects on host-induced plant defences may occur, these do not necessarily affect plant resistance concomitantly.

  8. Characterization of the symbiont Rickettsia in the mirid bug Nesidiocoris tenuis (Reuter) (Heteroptera: Miridae).

    Science.gov (United States)

    Caspi-Fluger, A; Inbar, M; Steinberg, S; Friedmann, Y; Freund, M; Mozes-Daube, N; Zchori-Fein, E

    2014-12-01

    Nesidiocoris tenuis (Reuter) (Heteroptera: Miridae) is an omnivorous insect used for biological control. Augmentative release and conservation of N. tenuis have been used for pest control in tomato crops. Intracellular bacterial symbionts of arthropods are common in nature and have diverse effects on their hosts; in some cases they can dramatically affect biological control. Fingerprinting methods showed that the symbiotic complex associated with N. tenuis includes Wolbachia and Rickettsia. Rickettsia of N. tenuis was further characterized by sequencing the 16S rRNA and gltA bacterial genes, measuring its amount in different developmental stages of the insect by real-time polymerase chain reaction, and localizing the bacteria in the insect's body by fluorescence in situ hybridization. The Rickettsia in N. tenuis exhibited 99 and 96% similarity of both sequenced genes to Rickettsia bellii and Rickettsia reported from Bemisia tabaci, respectively. The highest amount of Rickettsia was measured in the 5th instar and adult, and the symbionts could be detected in the host gut and ovaries. Although the role played by Rickettsia in the biology of N. tenuis is currently unknown, their high amount in the adults and localization in the gut suggest that they may have a nutritional role in this insect.

  9. Bacteriocins with a broader antimicrobial spectrum prevail in enterococcal symbionts isolated from the hoopoe's uropygial gland.

    Science.gov (United States)

    Ruiz-Rodríguez, Magdalena; Martínez-Bueno, Manuel; Martín-Vivaldi, Manuel; Valdivia, Eva; Soler, Juan J

    2013-09-01

    The use of compounds produced by symbiotic bacteria against pathogens in animals is one of the most exciting discoveries in ecological immunology. The study of those antibiotic metabolites will enable an understanding of the defensive strategies against pathogenic infections. Here, we explore the role of bacteriocins explaining the antimicrobial properties of symbiotic bacteria isolated from the uropygial gland of the hoopoe (Upupa epops). The antagonistic activity of 187 strains was assayed against eight indicator bacteria, and the presence of six bacteriocin genes was detected in the genomic DNA. The presence of bacteriocin genes correlated with the antimicrobial activity of isolates. The most frequently detected bacteriocin genes were those encoding for the MR10 and AS-48 enterocins, which confer the highest inhibition capacity. All the isolates belonged to the genus Enterococcus, with E. faecalis as the most abundant species, with the broadest antimicrobial spectrum and the highest antagonistic activity. The vast majority of E. faecalis strains carried the genes of MR10 and AS-48 in their genome. Therefore, we suggest that fitness-related benefits for hoopoes associated with harbouring the most bactericidal symbionts cause the highest frequency of strains carrying MR10 and AS-48 genes. The study of mechanisms associated with the acquisition and selection of bacterial symbionts by hoopoes is necessary, however, to reach further conclusions.

  10. THE ROLE OF BACTERIAL SYMBIONTS IN AMINO ACID COMPOSITION OF BLACK BEAN APHIDS

    Institute of Scientific and Technical Information of China (English)

    MingGan; De-ChengDing; Xue-xiaMiao

    2003-01-01

    To evaluate the role of bacterial symbionts ( Buchnera spp. ) in the black bean aphids ( Aphis craccivora Koch), the aphids were treated with the antibiotic, rifampicin, to eliminate their intracellular symbiotic bacteria. Analysis of protein and amino acid concentration in 7-day-old of aposymbiotic aphids showed that the total protein content per mg fresh weight was significantly reduced by 29 %, but free amino acid titers were increased by 17% . The ratio of the essential amino acids was in general only around 20% essential amino acids in phloem sap of broad bean, whereas it was 44% and 37% in symbiotic and aposymbiotic aphids, respectively,suggesting that the composition of the free amino acids was unbalanced. For example, the essential amino acid,threonine represented 21. 6% of essential amino acids in symbiotic aphids, but it was only 16.7% in aposymbiotic aphids. Likewise, two nonessential amino acids, tyrosine and serine, represented 8.9% and 5.6% of total amino acids in symbiontic aphids, respectively, but they enhanced to 21.1% and 13.6% in aposymbiotic aphids. It seems likely that the elevated free amino acid concentration in aposymbiotic aphids was caused by the limited protein anabolism as the result of the unbalanced amino acid composition.

  11. Building the crops of tomorrow: advantages of symbiont-based approaches to improving abiotic stress tolerance

    Energy Technology Data Exchange (ETDEWEB)

    Coleman-Derr, Devin [USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States); Tringe, Susannah G. [USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States)

    2014-06-06

    The exponential growth in world population is feeding a steadily increasing global need for arable farmland, a resource that is already in high demand. This trend has led to increased farming on subprime arid and semi-arid lands, where limited availability of water and a host of environmental stresses often severely reduce crop productivity. The conventional approach to mitigating the abiotic stresses associated with arid climes is to breed for stress-tolerant cultivars, a time and labor intensive venture that often neglects the complex ecological context of the soil environment in which the crop is grown. In recent years, studies have attempted to identify microbial symbionts capable of conferring the same stress-tolerance to their plant hosts, and new developments in genomic technologies have greatly facilitated such research. Here in this paper, we highlight many of the advantages of these symbiont-based approaches and argue in favor of the broader recognition of crop species as ecological niches for a diverse community of microorganisms that function in concert with their plant hosts and each other to thrive under fluctuating environmental conditions

  12. Response of the bacterial symbiont Holospora caryophila to different growth conditions of its host.

    Science.gov (United States)

    Castelli, Michele; Lanzoni, Olivia; Fokin, Sergei I; Schrallhammer, Martina; Petroni, Giulio

    2015-02-01

    Previous studies on bacterial symbionts of ciliates have shown that some symbionts can be maintained relatively well under standard laboratory conditions whereas others are frequently lost, especially when the host is cultivated at a high division rate. In this study, the variation in infection level by the endosymbiont Holospora caryophila within its host population Paramecium octaurelia was investigated in response to three alimentary treatments and a subsequent starvation phase. The response of the ciliates was determined as a nearly exponential growth rate with different slopes in each treatment, proportional to the amount of food received. The initial infection level was higher than 90%. After 24 days of exponential host's growth, the prevalence remained stable at approximately 90% in all treatments, even after a subsequent starvation phase of 20 days. However, at intermediate time-points in both the feeding and the starvation phase, fluctuations in the presence of the intracellular bacteria were observed. These results show that H. caryophila is able to maintain its infection under the tested range of host growth conditions, also due to the possibility of an effective re-infection in case of partial loss.

  13. Acetobacter tropicalis is a major symbiont of the olive fruit fly (Bactrocera oleae).

    Science.gov (United States)

    Kounatidis, Ilias; Crotti, Elena; Sapountzis, Panagiotis; Sacchi, Luciano; Rizzi, Aurora; Chouaia, Bessem; Bandi, Claudio; Alma, Alberto; Daffonchio, Daniele; Mavragani-Tsipidou, Penelope; Bourtzis, Kostas

    2009-05-01

    Following cultivation-dependent and -independent techniques, we investigated the microbiota associated with Bactrocera oleae, one of the major agricultural pests in olive-producing countries. Bacterial 16S rRNA gene libraries and ultrastructural analyses revealed the presence of several bacterial taxa associated with this insect, among which Acetobacter tropicalis was predominant. The recent increased detection of acetic acid bacteria as symbionts of other insect model organisms, such as Anopheles stephensi (G. Favia et al., Proc. Natl. Acad. Sci. USA 104:9047-9051, 2007) or Drosophila melanogaster (C. R. Cox and M. S. Gilmore, Infect. Immun. 75:1565-1576, 2007), prompted us to investigate the association established between A. tropicalis and B. oleae. Using an A. tropicalis-specific PCR assay, the symbiont was detected in all insects tested originating from laboratory stocks or field-collected from different locations in Greece. This acetic acid bacterium was successfully established in cell-free medium, and typing analyses, carried out on a collection of isolates, revealed that different A. tropicalis strains are present in fly populations. The capability to colonize and lodge in the digestive system of both larvae and adults and in Malpighian tubules of adults was demonstrated by using a strain labeled with a green fluorescent protein.

  14. Complete Genome Sequence of the Soybean Symbiont Bradyrhizobium japonicum Strain USDA6T

    Directory of Open Access Journals (Sweden)

    Nobukazu Uchiike

    2011-10-01

    Full Text Available The complete nucleotide sequence of the genome of the soybean symbiont Bradyrhizobium japonicum strain USDA6T was determined. The genome of USDA6T is a single circular chromosome of 9,207,384 bp. The genome size is similar to that of the genome of another soybean symbiont, B. japonicum USDA110 (9,105,828 bp. Comparison of the whole-genome sequences of USDA6T and USDA110 showed colinearity of major regions in the two genomes, although a large inversion exists between them. A significantly high level of sequence conservation was detected in three regions on each genome. The gene constitution and nucleotide sequence features in these three regions indicate that they may have been derived from a symbiosis island. An ancestral, large symbiosis island, approximately 860 kb in total size, appears to have been split into these three regions by unknown large-scale genome rearrangements. The two integration events responsible for this appear to have taken place independently, but through comparable mechanisms, in both genomes.

  15. Molecular identification of symbionts from the pulmonate snail Biomphalaria glabrata in Brazil.

    Science.gov (United States)

    Hertel, Lynn A; Barbosa, Contança S; Santos, Ricardo A A L; Loker, Eric S

    2004-08-01

    The icthyosporean, Capsaspora owczarzaki, a known predator of Schistosoma mansoni sporocysts in vitro, is more prevalent in laboratory-reared strains of the intermediate snail host, Biomphalaria glabrata resistant to S. mansoni, than from the susceptible M line strain. We examined whether B. glabrata resistant to the NIH-PR-1 strain of S. mansoni from 2 regions in Brazil were also host to C. owczarzaki. Symbiont presence was examined using hemolymph culturing and nested polymerase chain reaction of snail genomic DNA with primers designed to specifically amplify sequences from relatives of the Icthyosporea. All B. glabrata of the resistant Salvador strain from the laboratory of Dr. Lobato Paraense in Rio de Janeiro, Brazil (n = 46) tested negative for symbionts. Three of 18 semiresistant 10-R2 B. glabrata from the laboratory of Dr. Barbosa in Recife, Brazil tested positive for C. owczarzaki. Another icthyosporean, Anurofeca sp., was identified from 1, 10-R2 snail and from 2 of 12 field-collected B. glabrata from Praia do Forte Orange, Ilha de Itamaracá. Snails from 2 other sites, Hotel Colibri, Pontezinha and Praia do Sossego, Ilha de Itamaracá, were negative for Anurofeca. Two genera of ciliates were also identified. Paruroleptus sp. was found in 4, 10-R2 snails and Trichodina sp. was identified in 2 field-collected snails from Praia do Forte Orange and Praia do Sossego.

  16. Burkholderia and Cupriavidus spp. are the preferred symbionts of Mimosa spp. in southern China.

    Science.gov (United States)

    Liu, XiaoYun; Wei, Shuang; Wang, Fang; James, Euan K; Guo, XiaoYe; Zagar, Catherine; Xia, Liu Gui; Dong, Xin; Wang, Yi Peng

    2012-05-01

    Rhizobia were isolated from invasive Mimosa spp. (M. diplotricha and M. pudica) in Dehong district of the province of Yunnan in subtropical southern China. Almost all of the 98 isolates were β-rhizobia in the genera Burkholderia and Cupriavidus. These strains were analysed for their distribution characteristics together with strains from a previous study from Sishuangbanna. The proportion of nodules containing each β-rhizobial genus varied between Mimosa species, with Cupriavidus being predominant in M. diplotricha nodules (63.3% compared to 36.7% occupation with Burkholderia), but with M. pudica showing a slight preference for Burkholderia over Cupriavidus, with them occupying 56.5% and 43.5% of nodules, respectively. The symbiosis-essential genes nodA and nifH were present in all the Burkholderia and Cupriavidus strains tested, and their phylogenies indicated that these Mimosa symbionts share symbiotic genes with native South American rhizobia. The evolutionary discrepancies among 16S rRNA genes, nodA and nifH of Mimosa spp. symbionts, suggests that the nod and nif genes of β-rhizobia evolved independently. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  17. Gastrointestinal symbionts of chimpanzees in Cantanhez National Park, Guinea-Bissau with respect to habitat fragmentation.

    Science.gov (United States)

    Sá, Rui M; Petrášová, Jana; Pomajbíková, Kateřina; Profousová, Ilona; Petrželková, Klára J; Sousa, Cláudia; Cable, Joanne; Bruford, Michael W; Modrý, David

    2013-10-01

    One of the major factors threatening chimpanzees (Pan troglodytes verus) in Guinea-Bissau is habitat fragmentation. Such fragmentation may cause changes in symbiont dynamics resulting in increased susceptibility to infection, changes in host specificity and virulence. We monitored gastrointestinal symbiotic fauna of three chimpanzee subpopulations living within Cantanhez National Park (CNP) in Guinea Bissau in the areas with different levels of anthropogenic fragmentation. Using standard coproscopical methods (merthiolate-iodine formalin concentration and Sheather's flotation) we examined 102 fecal samples and identified at least 13 different symbiotic genera (Troglodytella abrassarti, Troglocorys cava, Blastocystis spp., Entamoeba spp., Iodamoeba butschlii, Giardia intestinalis, Chilomastix mesnili, Bertiella sp., Probstmayria gombensis, unidentified strongylids, Strongyloides stercoralis, Strongyloides fuelleborni, and Trichuris sp.). The symbiotic fauna of the CNP chimpanzees is comparable to that reported for other wild chimpanzee populations, although CNP chimpanzees have a higher prevalence of Trichuris sp. Symbiont richness was higher in chimpanzee subpopulations living in fragmented forests compared to the community inhabiting continuous forest area. We reported significantly higher prevalence of G. intestinalis in chimpanzees from fragmented areas, which could be attributed to increased contact with humans and livestock. © 2013 Wiley Periodicals, Inc.

  18. Hybridization in endophyte symbionts alters host response to moisture and nutrient treatments.

    Science.gov (United States)

    Hamilton, Cyd E; Dowling, Thomas E; Faeth, Stanley H

    2010-05-01

    When a host organism is infected by a symbiont, the resulting symbiotum has a phenotype distinct from uninfected hosts. Genotypic interactions between the partners may increase phenotypic variation of the host at the population level. Neotyphodium is an asexual, vertically transmitted endophytic symbiont of grasses often existing in hybrid form. Hybridization in Neotyphodium rapidly increases the symbiotum's genomic content and is likely to increase the phenotypic variation of the host. This phenotypic variation is predicted to enhance host performance, especially in stressful environments. We tested this hypothesis by comparing the growth, survival, and resource allocation of hybrid and nonhybrid infected host plants exposed to controlled variation in soil moisture and nutrients. Infection by a hybrid endophyte did not fit our predictions of comparatively higher root and total biomass production under low moisture/low nutrient treatments. Regardless of whether the host was infected by a hybrid or nonhybrid endophyte, both produced significantly higher root/total biomass when both nutrient and moisture were high compared to limited nutrient/moisture treatments. However, infection by hybrid Neotyphodium did result in significantly higher total biomass and host survival compared to nonhybrid infected hosts, regardless of treatment. Endophyte hybridization alters host strategies in response to stress by increasing survival in depauperate habitats and thus, potentially increasing the relative long-term host fitness.

  19. Independent Effects of a Herbivore’s Bacterial Symbionts on Its Performance and Induced Plant Defences

    Science.gov (United States)

    Staudacher, Heike; Schimmel, Bernardus C. J.; Lamers, Mart M.; Wybouw, Nicky; Groot, Astrid T.; Kant, Merijn R.

    2017-01-01

    It is well known that microbial pathogens and herbivores elicit defence responses in plants. Moreover, microorganisms associated with herbivores, such as bacteria or viruses, can modulate the plant’s response to herbivores. Herbivorous spider mites can harbour different species of bacterial symbionts and exert a broad range of effects on host-plant defences. Hence, we tested the extent to which such symbionts affect the plant’s defences induced by their mite host and assessed if this translates into changes in plant resistance. We assessed the bacterial communities of two strains of the common mite pest Tetranychus urticae. We found that these strains harboured distinct symbiotic bacteria and removed these using antibiotics. Subsequently, we tested to which extent mites with and without symbiotic bacteria induce plant defences in terms of phytohormone accumulation and defence gene expression, and assessed mite oviposition and survival as a measure for plant resistance. We observed that the absence/presence of these bacteria altered distinct plant defence parameters and affected mite performance but we did not find indications for a causal link between the two. We argue that although bacteria-related effects on host-induced plant defences may occur, these do not necessarily affect plant resistance concomitantly. PMID:28106771

  20. Horizontal roof gap of backfill hydraulic support

    Institute of Scientific and Technical Information of China (English)

    张强; 张吉雄; 邰阳; 方坤; 殷伟

    2015-01-01

    For the backfill hydraulic support as the key equipment for achieving integration of backfilling and coal mining simultaneously in the practical process, its characteristics will directly influence the backfill body’s compression ratio. Horizontal roof gap, as a key parameter of backfilling characteristics, may impact the backfilling effect from the aspects of control of roof subsidence in advance, support stress, backfilling process and the support design. Firstly, the reason why horizontal roof gap exists was analyzed and its definition, causes and connotation were introduced, then adopting the Pro/E 3D simulation software, three typical 3D entity models of backfill hydraulic supports were built, based on the influence of horizontal roof gap on backfilling effect, and influence rules of four factors, i.e. support height, suspension height, suspension angle and tamping angle, were emphatically analyzed on horizontal roof gap. The results indicate that, the four factors all have significant impacts on horizontal roof gap, but show differences in influence trend and degree, showing negative linear correlation, positive linear correlation, positive semi-parabolic correlation and negative semi-parabolic correlation, respectively. Four legs type is the most adaptive to the four factors, while six legs (II) type has the poorest adaptability, and the horizontal roof gap is small under large support height, small suspension height, small suspension angle and large tamping angle situation. By means of optimizing structure components and their positional relation and suspension height of backfill scrape conveyor in the process of support design and through controlling working face deployment, roof subsidence in advance, mining height and backfilling during engineering application, the horizontal roof gap is optimized. The research results can be served as theoretical basis for support design and guidance for backfill support to have better performance in backfilling.

  1. Horizontal alveolar bone loss: A periodontal orphan

    Directory of Open Access Journals (Sweden)

    Jayakumar A

    2010-01-01

    Full Text Available Background: Attempts to successfully regenerate lost alveolar bone have always been a clinician′s dream. Angular defects, at least, have a fairer chance, but the same cannot be said about horizontal bone loss. The purpose of the present study was to evaluate the prevalence of horizontal alveolar bone loss and vertical bone defects in periodontal patients; and later, to correlate it with the treatment modalities available in the literature for horizontal and vertical bone defects. Materials and Methods: The study was conducted in two parts. Part I was the radiographic evaluation of 150 orthopantomographs (OPGs (of patients diagnosed with chronic periodontitis and seeking periodontal care, which were digitized and read using the AutoCAD 2006 software. All the periodontitis-affected teeth were categorized as teeth with vertical defects (if the defect angle was ≤45° and defect depth was ≥3 mm or as having horizontal bone loss. Part II of the study comprised search of the literature on treatment modalities for horizontal and vertical bone loss in four selected periodontal journals. Results: Out of the 150 OPGs studied, 54 (36% OPGs showed one or more vertical defects. Totally, 3,371 teeth were studied, out of which horizontal bone loss was found in 3,107 (92.2% teeth, and vertical defects were found only in 264 (7.8% of the teeth, which was statistically significant (P<.001. Search of the selected journals revealed 477 papers have addressed the treatment modalities for vertical and horizontal types of bone loss specifically. Out of the 477 papers, 461 (96.3% have addressed vertical bone loss, and 18 (3.7% have addressed treatment options for horizontal bone loss. Two papers have addressed both types of bone loss and are included in both categories. Conclusion: Horizontal bone loss is more prevalent than vertical bone loss but has been sidelined by researchers as very few papers have been published on the subject of regenerative treatment

  2. Polygalacturonase from Sitophilus oryzae: Possible horizontal transfer of a pectinase gene from fungi to weevils

    Directory of Open Access Journals (Sweden)

    Zhicheng Shen

    2003-08-01

    Full Text Available Endo-polygalacturonase, one of the group of enzymes known collectively as pectinases, is widely distributed in bacteria, plants and fungi. The enzyme has also been found in several weevil species and a few other insects, such as aphids, but not in Drosophila melanogaster, Anopheles gambiae, or Caenorhabditis elegans or, as far as is known, in any more primitive animal species. What, then, is the genetic origin of the polygalacturonases in weevils? Since some weevil species harbor symbiotic microorganisms, it has been suggested, reasonably, that the symbionts' genomes of both aphids and weevils, rather than the insects' genomes, could encode polygalacturonase. We report here the cloning of a cDNA that encodes endo-polygalacturonase in the rice weevil, Sitophilus oryzae (L., and investigations based on the cloned cDNA. Our results, which include analysis of genes in antibiotic-treated rice weevils, indicate that the enzyme is, in fact, encoded by the insect genome. Given the apparent absence of the gene in much of the rest of the animal kingdom, it is therefore likely that the rice weevil polygalacturonase gene was incorporated into the weevil's genome by horizontal transfer, possibly from a fungus.

  3. Genome Sequence of Bradyrhizobium viridifuturi Strain SEMIA 690T, a Nitrogen-Fixing Symbiont of Centrosema pubescens

    Science.gov (United States)

    Helene, Luisa Caroline Ferraz; Gomes, Douglas Fabiano; Delamuta, Jakeline Renata Marçon; Ribeiro, Renan Augusto; Souza, Renata Carolini; Almeida, Luiz Gonzaga Paula; Vasconcelos, Ana Tereza Ribeiro

    2015-01-01

    SEMIA 690T is a nitrogen-fixing symbiont of Centrosema pubescens, and comprises the recently described species Bradyrhizobium viridifuturi. Its draft genome indicates that it belongs to the Bradyrhizobium elkanii superclade. SEMIA 690T carries two copies of the regulatory nodD gene, and the nod and nif operons resemble those of Bradyrhizobium diazoefficiens. PMID:26679590

  4. Intracellular levels of the viral symbiont CPV in Cryptosporidium parvum correlate with fecundity of the parasite in dairy calves

    Science.gov (United States)

    Previous reports have cited differences in clinical signs and oocyst output among strains of Cryptosporidium parvum. The purpose of this study was to determine if levels of the C. parvum intracellular viral symbiont CPV correlated with observed clinical and parasitological differences. Calves infe...

  5. Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia : Mollusca)

    NARCIS (Netherlands)

    Cavanaugh, Colleen M.; Abbott, Marilyn S.; Veenhuis, Marten

    1988-01-01

    The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP2Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large

  6. Fusarium symbionts of an ambrosia beetle (Euwallacea sp.) in southern Florida are pathogens of avocado, Persea americana

    Science.gov (United States)

    Fusarium dieback, a destructive disease of avocado (Persea americana), was reported in California and Israel in 2012. It is associated with an ambrosia beetle, Euwallacea sp., and damage caused by an unnamed symbiont of the beetle in Clade 3 of the Fusarium solani species complex (FSSC) designated p...

  7. Draft Genome Sequence of "Candidatus Hepatoplasma crinochetorum" Ps, a Bacterial Symbiont in the Hepatopancreas of the Terrestrial Isopod Porcellio scaber.

    Science.gov (United States)

    Collingro, Astrid; Kostanjšek, Rok; Toenshoff, Elena R; Schulz, Frederik; Schuster, Lisa; Domann, Daryl; Horn, Matthias

    2015-08-13

    "Candidatus Hepatoplasma crinochetorum" Ps is an extracellular symbiont residing in the hepatopancreas of the terrestrial isopod Porcellio scaber. Its genome is highly similar to that of the close relative "Ca. Hepatoplasma crinochetorum" Av from Armadillidium vulgare. However, instead of a clustered regularly interspaced short palindromic repeat (CRISPR)-Cas system, it encodes a type I restriction modification system.

  8. Algal symbiont type affects gene expression in juveniles of the coral Acropora tenuis exposed to thermal stress.

    Science.gov (United States)

    Yuyama, Ikuko; Harii, Saki; Hidaka, Michio

    2012-05-01

    Reef-building corals harbor symbiotic dinoflagellates, Symbiodinium spp., which are currently divided into several clades. The responses of corals associated with different Symbiodinium clades to thermal stress are not well understood, especially at a gene expression level. Juveniles of the coral Acropora tenuis inoculated with different algal types (clade A or D) were exposed to thermal stress and the expression levels of four putative stress-responsive genes, including genes coding green and red fluorescent proteins, an oxidative stress-responsive protein, and an ascorbic acid transporter, were analyzed by quantitative real-time PCR. The expression levels of the four genes decreased at high temperatures if juveniles were associated with clade A symbionts but increased if the symbionts were in clade D. The intensity of green fluorescence increased with temperature in clade D symbionts harboring juveniles, but not in juveniles associated with clade A symbionts. The present results suggest that genotypes of endosymbiotic algae affect the thermal stress responses of the coral juveniles.

  9. Bacterial symbiont sharing in Megalomyrmex social parasites and their fungus-growing ant hosts

    DEFF Research Database (Denmark)

    Liberti, Joanito; Sapountzis, Panagiotis; Hansen, Lars H.;

    2015-01-01

    intensities and are distantly related. We used tag-encoded FLX 454 pyrosequencing and diagnostic PCR to map bacterial symbiont diversity across the Megalomyrmex phylogenetic tree, which also contains free-living generalist predators. We show that social parasites and hosts share a subset of bacterial...

  10. Intraspecific Variation in Microbial Symbiont Communities of the Sun Sponge, Hymeniacidon heliophila, from Intertidal and Subtidal Habitats.

    Science.gov (United States)

    Weigel, Brooke L; Erwin, Patrick M

    2015-11-13

    Sponges host diverse and complex communities of microbial symbionts that display a high degree of host specificity. The microbiomes of conspecific sponges are relatively constant, even across distant locations, yet few studies have directly examined the influence of abiotic factors on intraspecific variation in sponge microbial community structure. The contrast between intertidal and subtidal environments is an ideal system to assess the effect of environmental variation on sponge-microbe symbioses, producing two drastically different environments on a small spatial scale. Here, we characterized the microbial communities of individual intertidal and subtidal Hymeniacidon heliophila sponges, ambient seawater, and sediment from a North Carolina oyster reef habitat by partial (Illumina sequencing) and nearly full-length (clone libraries) 16S rRNA gene sequence analyses. Clone library sequences were compared to H. heliophila symbiont communities from the Gulf of Mexico and Brazil, revealing strong host specificity of dominant symbiont taxa across expansive geographic distances. Sediment and seawater samples yielded clearly distinct microbial communities from those found in H. heliophila. Despite the close proximity of the sponges sampled, significant differences between subtidal and intertidal sponges in the diversity, structure, and composition of their microbial communities were detected. Differences were driven by changes in the relative abundance of a few dominant microbial symbiont taxa, as well as the presence or absence of numerous rare microbial taxa. These findings suggest that extreme abiotic fluctuations, such as periodic air exposure in intertidal habitats, can drive intraspecific differences in complex host-microbe symbioses.

  11. Characterizing the host and symbiont proteomes in the association between the Bobtail squid, Euprymna scolopes, and the bacterium, Vibrio fischeri.

    Directory of Open Access Journals (Sweden)

    Tyler R Schleicher

    Full Text Available The beneficial symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium, Vibrio fischeri, provides a unique opportunity to study host/microbe interactions within a natural microenvironment. Colonization of the squid light organ by V. fischeri begins a lifelong association with a regulated daily rhythm. Each morning the host expels an exudate from the light organ consisting of 95% of the symbiont population in addition to host hemocytes and shed epithelial cells. We analyzed the host and symbiont proteomes of adult squid exudate and surrounding light organ epithelial tissue using 1D- and 2D-polyacrylamide gel electrophoresis and multidimensional protein identification technology (MudPIT in an effort to understand the contribution of both partners to the maintenance of this association. These proteomic analyses putatively identified 1581 unique proteins, 870 proteins originating from the symbiont and 711 from the host. Identified host proteins indicate a role of the innate immune system and reactive oxygen species (ROS in regulating the symbiosis. Symbiont proteins detected enhance our understanding of the role of quorum sensing, two-component signaling, motility, and detoxification of ROS and reactive nitrogen species (RNS inside the light organ. This study offers the first proteomic analysis of the symbiotic microenvironment of the adult light organ and provides the identification of proteins important to the regulation of this beneficial association.

  12. Burkholderia phymatum is a highly effective nitrogen-fixing symbiont of Mimosa spp. and fixes nitrogen ex planta.

    Science.gov (United States)

    Elliott, Geoffrey N; Chen, Wen-Ming; Chou, Jui-Hsing; Wang, Hui-Chun; Sheu, Shih-Yi; Perin, Liamara; Reis, Veronica M; Moulin, Lionel; Simon, Marcelo F; Bontemps, Cyril; Sutherland, Joan M; Bessi, Rosana; de Faria, Sergio M; Trinick, Michael J; Prescott, Alan R; Sprent, Janet I; James, Euan K

    2007-01-01

    * The ability of Burkholderia phymatum STM815 to effectively nodulate Mimosa spp., and to fix nitrogen ex planta, was compared with that of the known Mimosa symbiont Cupriavidus taiwanensis LMG19424. * Both strains were equally effective symbionts of M. pudica, but nodules formed by STM815 had greater nitrogenase activity. STM815 was shown to have a broader host range across the genus Mimosa than LMG19424, nodulating 30 out of 31 species, 21 of these effectively. LMG19424 effectively nodulated only nine species. GFP-marked variants were used to visualise symbiont presence within nodules. * STM815 gave significant acetylene reduction assay (ARA) activity in semisolid JMV medium ex planta, but no ARA activity was detected with LMG19424. 16S rDNA sequences of two isolates originally from Mimosa nodules in Papua New Guinea (NGR114 and NGR195A) identified them as Burkholderia phymatum also, with nodA, nodC and nifH genes of NGR195A identical to those of STM815. * B. phymatum is therefore an effective Mimosa symbiont with a broad host range, and is the first reported beta-rhizobial strain to fix nitrogen in free-living culture.

  13. Diffuser Augmented Horizontal Axis Tidal Current Turbines

    Directory of Open Access Journals (Sweden)

    Nasir Mehmood

    2012-09-01

    Full Text Available The renewal energy technologies are increasingly popular to ensure future energy sustenance and address environmental issues. The tides are enormous and consistent untapped resource of renewable energy. The growing interest in exploring tidal energy has compelling reasons such as security and diversity of supply, intermittent but predictable and limited social and environmental impacts. The tidal energy industry is undergoing an increasing shift towards diffuser augmented turbines. The reason is the higher power output of diffuser augmented turbines compared to conventional open turbines. The purpose of this study is to present a comprehensive review of diffuser augmented horizontal axis tidal current turbines. The components, relative advantages, limitations and design parameters of diffuser augmented horizontal axis tidal current turbines are presented in detail. CFD simulation of NACA 0016 airfoil is carried out to explore its potential for designing a diffuser. The core issues associated with diffuser augmented horizontal axis tidal current turbines are also discussed.

  14. HORIZONTAL WELL DRILL-IN FLUIDS

    Directory of Open Access Journals (Sweden)

    Nediljka Gaurina-Međimurec

    1998-12-01

    Full Text Available Main objective of horizontal driling is to place a drain-hole for a long distance within the pay zone to enhance productivity or injectivity. In drilling horizontal wells, more serious problems appear than in drilling vertical wells. These problems are: poor hole cleaning, excessive torque and drag, hole filling, pipe stucking, wellbore instability, loss of circulation, formation damage, poor cement job, and difficulties at logging jobs. From that reason, successful drilling and production of horizontal well depends largely on the fluid used during drilling and completion phases. Several new fluids, that fulfill some or all of required properties (hole cleaning, cutting suspension, good lubrication, and relative low formation damage, are presented in this paper.

  15. Horizontal stirring in the global ocean

    CERN Document Server

    Hernández-Carrasco, I; Hernández-García, E; Turiel, A

    2011-01-01

    Horizontal mixing and the distribution of coherent structures in the global ocean are analyzed using Finite-Size Lyapunov Exponents (FSLE), computed for the surface velocity field derived from the Ocean general circulation model For the Earth Simulator (OFES). FSLEs measure horizontal stirring and dispersion; additionally, the transport barriers which organize the oceanic flow can roughly be identified with the ridges of the FSLE field. We have performed a detailed statistical study, particularizing for the behaviour of the two hemispheres and different ocean basins. The computed Probability Distributions Functions (PDFs) of FSLE are broad and asymmetric. Horizontal mixing is generally more active in the northern hemisphere than in the southern one. Nevertheless the Southern Ocean is the most active ocean, and the Pacific the less active one. A striking result is that the main currents can be classified in two 'activity classes': Western Boundary Currents, which have broad PDFs with large FSLE values, and Eas...

  16. Wolbachia symbiont infections induce strong cytoplasmic incompatibility in the tsetse fly Glossina morsitans.

    Directory of Open Access Journals (Sweden)

    Uzma Alam

    2011-12-01

    Full Text Available Tsetse flies are vectors of the protozoan parasite African trypanosomes, which cause sleeping sickness disease in humans and nagana in livestock. Although there are no effective vaccines and efficacious drugs against this parasite, vector reduction methods have been successful in curbing the disease, especially for nagana. Potential vector control methods that do not involve use of chemicals is a genetic modification approach where flies engineered to be parasite resistant are allowed to replace their susceptible natural counterparts, and Sterile Insect technique (SIT where males sterilized by chemical means are released to suppress female fecundity. The success of genetic modification approaches requires identification of strong drive systems to spread the desirable traits and the efficacy of SIT can be enhanced by identification of natural mating incompatibility. One such drive mechanism results from the cytoplasmic incompatibility (CI phenomenon induced by the symbiont Wolbachia. CI can also be used to induce natural mating incompatibility between release males and natural populations. Although Wolbachia infections have been reported in tsetse, it has been a challenge to understand their functional biology as attempts to cure tsetse of Wolbachia infections by antibiotic treatment damages the obligate mutualistic symbiont (Wigglesworthia, without which the flies are sterile. Here, we developed aposymbiotic (symbiont-free and fertile tsetse lines by dietary provisioning of tetracycline supplemented blood meals with yeast extract, which rescues Wigglesworthia-induced sterility. Our results reveal that Wolbachia infections confer strong CI during embryogenesis in Wolbachia-free (Gmm(Apo females when mated with Wolbachia-infected (Gmm(Wt males. These results are the first demonstration of the biological significance of Wolbachia infections in tsetse. Furthermore, when incorporated into a mathematical model, our results confirm that Wolbachia can

  17. Variable interaction specificity and symbiont performance in Panamanian Trachymyrmex and Sericomyrmex fungus-growing ants.

    Science.gov (United States)

    De Fine Licht, Henrik H; Boomsma, Jacobus J

    2014-12-04

    Cooperative benefits of mutualistic interactions are affected by genetic variation among the interacting partners, which may have consequences for interaction-specificities across guilds of sympatric species with similar mutualistic life histories. The gardens of fungus-growing (attine) ants produce carbohydrate active enzymes that degrade plant material collected by the ants and offer them food in exchange. The spectrum of these enzyme activities is an important symbiont service to the host but may vary among cultivar genotypes. The sympatric occurrence of several Trachymyrmex and Sericomyrmex higher attine ants in Gamboa, Panama provided the opportunity to do a quantitative study of species-level interaction-specificity. We genotyped the ants for Cytochrome Oxidase and their Leucoagaricus fungal cultivars for ITS rDNA. Combined with activity measurements for 12 carbohydrate active enzymes, these data allowed us to test whether garden enzyme activity was affected by fungal strain, farming ants or combinations of the two. We detected two cryptic ant species, raising ant species number from four to six, and we show that the 38 sampled colonies reared a total of seven fungal haplotypes that were different enough to represent separate Leucoagaricus species. The Sericomyrmex species and one of the Trachymyrmex species reared the same fungal cultivar in all sampled colonies, but the remaining four Trachymyrmex species largely shared the other cultivars. Fungal enzyme activity spectra were significantly affected by both cultivar species and farming ant species, and more so for certain ant-cultivar combinations than others. However, relative changes in activity of single enzymes only depended on cultivar genotype and not on the ant species farming a cultivar. Ant cultivar symbiont-specificity varied from almost full symbiont sharing to one-to-one specialization, suggesting that trade-offs between enzyme activity spectra and life-history traits such as desiccation

  18. El horizonte estético

    OpenAIRE

    Perniola, Mario

    2004-01-01

    La existencia de un horizonte estético depende de la coexistencia de múltiples factores de distinta naturaleza que interactúan entre ellos. No bastan las reflexiones en torno a lo bello y al arte para crear un horizonte estético. La palabra “estética” es introducida en el Settecento por la filosofía para indicar una articulación disciplinar propia que pudiera ubicarse cerca de la lógica; esta circunstancia histórica, sin embargo, no debe hacernos olvidar que la filosofía es desde su nacimient...

  19. Fourth international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    Tuomisto, H. [ed.] [IVO Group, Vantaa (Finland); Purhonen, H. [ed.] [VTT, Espoo (Finland); Kouhia, V. [ed.] [Lappeenranta Univ. of Technology (Finland)

    1997-12-31

    The general objective of the International Seminars of Horizontal Steam Generator Modelling has been the improvement in understanding of realistic thermal hydraulic behaviour of the generators when performing safety analyses for VVER reactors. The main topics presented in the fourth seminar were: thermal hydraulic experiments and analyses, primary collector integrity, feedwater distributor replacement, management of primary-to-secondary leakage accidents and new developments in the VVER safety technology. The number of participants, representing designers and manufacturers of the horizontal steam generators, plant operators, engineering companies, research organizations, universities and regulatory authorities, was 70 from 10 countries.

  20. Horizontal Roll Vortices and Crown Fires.

    Science.gov (United States)

    Haines, Donald A.

    1982-06-01

    Observational evidence from nine crown fires suggests that horizontal roll vortices are a major mechanism in crown-fire spread. Post-burn aerial photography indicates that unburned tree-crown streets are common with crown fire. Investigation of the understory of these crown streets after two fires showed uncharred tree trunks along a center line. This evidence supports a hypothesis of vortex action causing strong downward motion of air along the streets. Additionally, photographs of two ongoing crown fires show apparent horizontal roll vortices. Discussion also includes laboratory and numerical studies in fluid dynamics that may apply to crown fires.

  1. The inadequacy of morphology for species and genus delineation in microbial eukaryotes: an example from the parabasalian termite symbiont coronympha.

    Directory of Open Access Journals (Sweden)

    James T Harper

    Full Text Available BACKGROUND: For the majority of microbial eukaryotes (protists, algae, there is no clearly superior species concept that is consistently applied. In the absence of a practical biological species concept, most species and genus level delineations have historically been based on morphology, which may lead to an underestimate of the diversity of microbial eukaryotes. Indeed, a growing body of molecular evidence, such as barcoding surveys, is beginning to support the conclusion that significant cryptic species diversity exists. This underestimate of diversity appears to be due to a combination of using morphology as the sole basis for assessing diversity and our inability to culture the vast majority of microbial life. Here we have used molecular markers to assess the species delineations in two related but morphologically distinct genera of uncultivated symbionts found in the hindgut of termites. METHODOLOGY/PRINCIPAL FINDINGS: Using single-cell isolation and environmental PCR, we have used a barcoding approach to characterize the diversity of Coronympha and Metacoronympha symbionts in four species of Incisitermes termites, which were also examined using scanning electron microscopy and light microcopy. Despite the fact that these genera are significantly different in morphological complexity and structural organisation, we find they are two life history stages of the same species. At the same time, we show that the symbionts from different termite hosts show an equal or greater level of sequence diversity than do the hosts, despite the fact that the symbionts are all classified as one species. CONCLUSIONS/SIGNIFICANCE: The morphological information used to describe the diversity of these microbial symbionts is misleading at both the genus and species levels, and led to an underestimate of species level diversity as well as an overestimate of genus level diversity. The genus 'Metacoronympha' is invalid and appears to be a life history stage of

  2. A Single Host-Derived Glycan Impacts Key Regulatory Nodes of Symbiont Metabolism in a Coevolved Mutualism.

    Science.gov (United States)

    Pan, Min; Schwartzman, Julia A; Dunn, Anne K; Lu, Zuhong; Ruby, Edward G

    2015-07-14

    Most animal-microbe mutualistic associations are characterized by nutrient exchange between the partners. When the host provides the nutrients, it can gain the capacity to shape its microbial community, control the stability of the interaction, and promote its health and fitness. Using the bioluminescent squid-vibrio model, we demonstrate how a single host-derived glycan, chitin, regulates the metabolism of Vibrio fischeri at key points in the development and maintenance of the symbiosis. We first characterized the pathways for catabolism of chitin sugars by V. fischeri, demonstrating that the Ccr-dependent phosphoenolpyruvate-pyruvate phosphotransferase system (PTS) prioritizes transport of these sugars in V. fischeri by blocking the uptake of non-PTS carbohydrates, such as glycerol. Next, we found that PTS transport of chitin sugars into the bacterium shifted acetate homeostasis toward a net excretion of acetate and was sufficient to override an activation of the acetate switch by AinS-dependent quorum sensing. Finally, we showed that catabolism of chitin sugars decreases the rate of cell-specific oxygen consumption. Collectively, these three metabolic functions define a physiological shift that favors fermentative growth on chitin sugars and may support optimal symbiont luminescence, the functional basis of the squid-vibrio mutualism. Host-derived glycans have recently emerged as a link between symbiont nutrition and innate immune function. Unfortunately, the locations at which microbes typically access host-derived glycans are inaccessible to experimentation and imaging, and they take place in the context of diverse microbe-microbe interactions, creating a complex symbiotic ecology. Here we describe the metabolic state of a single microbial symbiont in a natural association with its coevolved host and, by doing so, infer key points at which a host-controlled tissue environment might regulate the physiological state of its symbionts. We show that the presence of

  3. The effect of transmission route on plant virus epidemic development and disease control.

    Science.gov (United States)

    Jeger, Michael J; Madden, Laurence V; van den Bosch, Frank

    2009-05-21

    A model for indirect vector transmission and epidemic development of plant viruses is extended to consider direct transmission through vector mating. A basic reproduction number is derived which is the sum of the R(0) values specific for three transmission routes. We analyse the model to determine the effect of direct transmission on plant disease control directed against indirect transmission. Increasing the rate of horizontal sexual transmission means that vector control rate or indirect transmission rate must be increased/decreased substantially to maintain R(0) at a value less than 1. By contrast, proportionately increasing the probability of transovarial transmission has little effect. Expressions are derived for the steady-state values of the viruliferous vector population. There is clear advantage for an insect virus in indirect transmission to plants, especially where the sexual and transovarial transmission rates are low; however information on virulence-transmissibility relationships is required to explain the evolution of a plant virus from an insect virus.

  4. Exploring the potential for actinobacteria as defensive symbionts in fungus-growing termites

    DEFF Research Database (Denmark)

    Visser, Anna A.; Nobre, Tânia; Currie, Cameron R.

    2012-01-01

    In fungus-growing termites, fungi of the subgenus Pseudoxylaria threaten colony health through substrate competition with the termite fungus (Termitomyces). The potential mechanisms with which termites suppress Pseudoxylaria have remained unknown. Here we explore if Actinobacteria potentially play...... a role as defensive symbionts against Pseudoxylaria in fungus-growing termites. We sampled for Actinobacteria from 30 fungus-growing termite colonies, spanning the three main termite genera and two geographically distant sites. Our isolations yielded 360 Actinobacteria, from which we selected subsets......-growing termites, indicating lack of specificity. Antibiotic-activity screening of 288 isolates against the fungal cultivar and competitor revealed that most of the Actinobacteria-produced molecules with antifungal activity. A more detailed bioassay on 53 isolates, to test the specificity of antibiotics, showed...

  5. Variable interaction specificity and symbiont performance in Panamanian Trachymyrmex and Sericomyrmex fungus-growing ants

    DEFF Research Database (Denmark)

    de Fine Licht, Henrik Hjarvard; Boomsma, Jacobus Jan

    2014-01-01

    ) ants produce carbohydrate active enzymes that degrade plant material collected by the ants and offer them food in exchange. The spectrum of these enzyme activities is an important symbiont service to the host but may vary among cultivar genotypes. The sympatric occurrence of several Trachymyrmex...... and Sericomyrmex higher attine ants in Gamboa, Panama provided the opportunity to do a quantitative study of species-level interaction-specificity. Results We genotyped the ants for Cytochrome Oxidase and their Leucoagaricus fungal cultivars for ITS rDNA. Combined with activity measurements for 12 carbohydrate......Background Cooperative benefits of mutualistic interactions are affected by genetic variation among the interacting partners, which may have consequences for interaction-specificities across guilds of sympatric species with similar mutualistic life histories. The gardens of fungus-growing (attine...

  6. Condition-specific RNA editing in the coral symbiont Symbiodinium microadriaticum

    KAUST Repository

    Liew, Yi Jin

    2017-03-01

    RNA editing is a rare post-transcriptional event that provides cells with an additional level of gene expression regulation. It has been implicated in various processes including adaptation, viral defence and RNA interference; however, its potential role as a mechanism in acclimatization has just recently been recognised. Here, we show that RNA editing occurs in 1.6% of all nuclear-encoded genes of Symbiodinium microadriaticum, a dinoflagellate symbiont of reef-building corals. All base-substitution edit types were present, and statistically significant motifs were associated with three edit types. Strikingly, a subset of genes exhibited condition-specific editing patterns in response to different stressors that resulted in significant increases of non-synonymous changes. We posit that this previously unrecognised mechanism extends this organism’s capability to respond to stress beyond what is encoded by the genome. This in turn may provide further acclimatization capacity to these organisms, and by extension, their coral hosts.

  7. Symbiont-derived beta-1,3-glucanases in a social insect: mutualism beyond nutrition

    Directory of Open Access Journals (Sweden)

    Rebeca B Rosengaus

    2014-11-01

    Full Text Available Termites have had a long co-evolutionary history with prokaryotic and eukaryotic gut microbes. Historically, the role of these anaerobic obligate symbionts has been attributed to the nutritional welfare of the host. We provide evidence that protozoa (and/or their associated bacteria colonizing the hindgut of the dampwood termite Zootermopsis angusticollis, synthesize multiple functional beta-1,3-glucanases, enzymes known for breaking down beta-1,3-glucans, the main component of fungal cell walls. These enzymes, we propose, may help in both digestion of ingested fungal hyphae and protection against invasion by fungal pathogens. This research points to an additional novel role for the mutualistic hindgut microbial consortia of termites, an association that may extend beyond ligno-cellulolytic activity and nitrogen fixation to include a reduction in the risks of mycosis at both the individual- and colony-levels while nesting in and feeding on microbial-rich decayed wood.

  8. Complementary symbiont contributions to plant decomposition in a fungus-farming termite

    DEFF Research Database (Denmark)

    Thomas-Poulsen, Michael; Hu, Haofu; Li, Cai

    2014-01-01

    Termites normally rely on gut symbionts to decompose organic matter but the Macrotermitinae domesticated Termitomyces fungi to produce their own food. This transition was accompanied by a shift in the composition of the gut microbiota, but the complementary roles of these bacteria in the symbiosis...... in the symbiosis, that Termitomyces has the genomic capacity to handle complex carbohydrates, and that worker gut microbes primarily contribute enzymes for final digestion of oligosaccharides. This apparent division of labor is consistent with the Macrotermes gut microbes being most important during the second...... appears to be mainly accomplished by complementary cooperation between a domesticated fungal monoculture and a specialized bacterial community. In sharp contrast, the gut microbiota of the queen had highly reduced plant decomposition potential, suggesting that mature reproductives digest fungal material...

  9. Host Matters: Medicinal Leech Digestive-Tract Symbionts and their Pathogenic Potential

    Directory of Open Access Journals (Sweden)

    Jeremiah Marden

    2016-10-01

    Full Text Available Digestive-tract microbiota exert tremendous influence over host health. Host-symbiont model systems are studied to investigate how symbioses are initiated and maintained, as well as to identify host processes affected by resident microbiota. The medicinal leech, Hirudo verbana, is an excellent model to address such questions owing to a microbiome that is consistently dominanted by two species, Aeromonas veronii and Mucinivorans hirudinis, both of which are cultivable and have sequenced genomes. This review outlines current knowledge about the dynamics of the H. verbana microbiome. We discuss in depth the factors required for A. veronii colonization and proliferation in the leech crop and summarize the current understanding of interactions between A. veronii and its annelid host. Lastly, we discuss leech usage in modern medicine and highlight how leech-therapy associated infections, often attributable to Aeromonas spp., are of growing clinical concern due in part to an increased prevalence of fluoroquinolone resistant strains.

  10. A novel test for host-symbiont codivergence indicates ancient origin of fungal endophytes in grasses

    CERN Document Server

    Schardl, Chris L; Lindstrom, Adam; Speakman, Skyler; Stromberg, Arnold; Yoshida, Ruriko

    2007-01-01

    Significant phylogenetic codivergence between plant or animal hosts ($H$) and their symbionts or parasites ($P$) indicate the importance of their interactions on evolutionary time scales. However, valid and realistic methods to test for codivergence are not fully developed. One of the systems where possible codivergence has been of interest involves the large subfamily of temperate grasses (Pooideae) and their endophytic fungi (epichloae). These widespread symbioses often help protect host plants from herbivory and stresses, and affect species diversity and food web structures. Here we introduce the MRCALink (most-recent-common-ancestor link) method and use it to investigate the possibility of grass-epichlo\\"e codivergence. MRCALink applied to ultrametric $H$ and $P$ trees identifies all corresponding nodes for pairwise comparisons of MRCA ages. The result is compared to the space of random $H$ and $P$ tree pairs estimated by a Monte Carlo method.

  11. Bacterial symbionts in agricultural systems provide a strategic source for antibiotic discovery.

    Science.gov (United States)

    Ramadhar, Timothy R; Beemelmanns, Christine; Currie, Cameron R; Clardy, Jon

    2014-01-01

    As increased antibiotic resistance erodes the efficacy of currently used drugs, the need for new candidates with therapeutic potential grows. Although the majority of antibiotics in clinical use originated from natural products, mostly from environmental actinomycetes, high rediscovery rates, among other factors, have diminished the enthusiasm for continued exploration of this historically important source. Several well-studied insect agricultural systems have bacterial symbionts that have evolved to produce small molecules that suppress environmental pathogens. These molecules represent an underexplored reservoir of potentially useful antibiotics. This report describes the multilateral symbioses common to insect agricultural systems, the general strategy used for antibiotic discovery and pertinent examples from three farming systems: fungus-farming ants, southern pine beetles (SPBs) and fungus-growing termites.

  12. The structured diversity of specialized gut symbionts of the New World army ants.

    Science.gov (United States)

    Łukasik, Piotr; Newton, Justin A; Sanders, Jon G; Hu, Yi; Moreau, Corrie S; Kronauer, Daniel J C; O'Donnell, Sean; Koga, Ryuichi; Russell, Jacob A

    2017-04-10

    Symbiotic bacteria play important roles in the biology of their arthropod hosts. Yet the microbiota of many diverse and influential groups remain understudied, resulting in a paucity of information on the fidelities and histories of these associations. Motivated by prior findings from a smaller scale, 16S rRNA-based study, we conducted a broad phylogenetic and geographical survey of microbial communities in the ecologically dominant New World army ants (Formicidae: Dorylinae). Amplicon sequencing of the 16S rRNA gene across 28 species spanning the five New World genera showed that the microbial communities of army ants consist of very few common and abundant bacterial species. The two most abundant microbes, referred to as Unclassified Firmicutes and Unclassified Entomoplasmatales, appear to be specialized army ant associates that dominate microbial communities in the gut lumen of three host genera, Eciton, Labidus, and Nomamyrmex. Both are present in other army ant genera, including those from the Old World, suggesting that army ant symbioses date back to the Cretaceous. Extensive sequencing of bacterial protein-coding genes revealed multiple strains of these symbionts co-existing within colonies, but seldom within the same individual ant. Bacterial strains formed multiple host species-specific lineages on phylogenies, which often grouped strains from distant geographic locations. These patterns deviate from those seen in other social insects and raise intriguing questions about the influence of army ant colony swarm-founding and within-colony genetic diversity on strain co-existence, and the effects of hosting a diverse suite of symbiont strains on colony ecology. This article is protected by copyright. All rights reserved.

  13. Laccase detoxification mediates the nutritional alliance between leaf-cutting ants and fungus-garden symbionts.

    Science.gov (United States)

    De Fine Licht, Henrik H; Schiøtt, Morten; Rogowska-Wrzesinska, Adelina; Nygaard, Sanne; Roepstorff, Peter; Boomsma, Jacobus J

    2013-01-08

    Leaf-cutting ants combine large-scale herbivory with fungus farming to sustain advanced societies. Their stratified colonies are major evolutionary achievements and serious agricultural pests, but the crucial adaptations that allowed this mutualism to become the prime herbivorous component of neotropical ecosystems has remained elusive. Here we show how coevolutionary adaptation of a specific enzyme in the fungal symbiont has helped leaf-cutting ants overcome plant defensive phenolic compounds. We identify nine putative laccase-coding genes in the fungal genome of Leucocoprinus gongylophorus cultivated by the leaf-cutting ant Acromyrmex echinatior. One of these laccases (LgLcc1) is highly expressed in the specialized hyphal tips (gongylidia) that the ants preferentially eat, and we confirm that these ingested laccase molecules pass through the ant guts and remain active when defecated on the leaf pulp that the ants add to their gardens. This accurate deposition ensures that laccase activity is highest where new leaf material enters the fungus garden, but where fungal mycelium is too sparse to produce extracellular enzymes in sufficient quantities to detoxify phenolic compounds. Phylogenetic analysis of LgLcc1 ortholog sequences from symbiotic and free-living fungi revealed significant positive selection in the ancestral lineage that gave rise to the gongylidia-producing symbionts of leaf-cutting ants and their non-leaf-cutting ant sister group. Our results are consistent with fungal preadaptation and subsequent modification of a particular laccase enzyme for the detoxification of secondary plant compounds during the transition to active herbivory in the ancestor of leaf-cutting ants between 8 and 12 Mya.

  14. Bacterial gut symbionts contribute to seed digestion in an omnivorous beetle.

    Directory of Open Access Journals (Sweden)

    Jonathan G Lundgren

    Full Text Available BACKGROUND: Obligate bacterial symbionts alter the diets of host animals in numerous ways, but the ecological roles of facultative bacterial residents that colonize insect guts remain unclear. Carabid beetles are a common group of beneficial insects appreciated for their ability to consume insect prey and seeds, but the contributions of microbes to diet diversification in this and similar groups of facultative granivores are largely unknown. METHODOLOGY AND PRINCIPAL FINDINGS: Using 16S rRNA gene clone libraries and terminal restriction fragment (tRF length polymorphism analyses of these genes, we examined the bacterial communities within the guts of facultatively granivorous, adult Harpalus pensylvanicus (Carabidae, fed one of five dietary treatments: 1 an untreated Field population, 2 Seeds with antibiotics (seeds were from Chenopodium album, 3 Seeds without antibiotics, 4 Prey with antibiotics (prey were Acheta domesticus eggs, and 5 Prey without antibiotics. The number of seeds and prey consumed by each beetle were recorded following treatment. Harpalus pensylvanicus possessed a fairly simple gut community of approximately 3-4 bacterial operational taxonomic units (OTU per beetle that were affiliated with the Gammaproteobacteria, Bacilli, Alphaproteobacteria, and Mollicutes. Bacterial communities of the host varied among the diet and antibiotic treatments. The field population and beetles fed seeds without antibiotics had the closest matching bacterial communities, and the communities in the beetles fed antibiotics were more closely related to each other than to those of the beetles that did not receive antibiotics. Antibiotics reduced and altered the bacterial communities found in the beetle guts. Moreover, beetles fed antibiotics ate fewer seeds, and those beetles that harbored the bacterium Enterococcus faecalis consumed more seeds on average than those lacking this symbiont. CONCLUSIONS/SIGNIFICANCE: We conclude that the relationships

  15. The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.

    Science.gov (United States)

    Goulet, Tamar L.; Shirur, Kartick P.; Ramsby, Blake D.; Iglesias-Prieto, Roberto

    2017-01-01

    Global climate change not only leads to elevated seawater temperatures but also to episodic anomalously high or low temperatures lasting for several hours to days. Scleractinian corals are detrimentally affected by thermal fluctuations, which often lead to an uncoupling of their mutualism with Symbiodinium spp. (coral bleaching) and potentially coral death. Consequently, on many Caribbean reefs scleractinian coral cover has plummeted. Conversely, gorgonian corals persist, with their abundance even increasing. How gorgonians react to thermal anomalies has been investigated utilizing limited parameters of either the gorgonian, Symbiodinium or the combined symbiosis (holobiont). We employed a holistic approach to examine the effect of an experimental five-day elevated temperature episode on parameters of the host, symbiont, and the holobiont in Eunicea tourneforti, E. flexuosa and Pseudoplexaura porosa. These gorgonian corals reacted and coped with 32°C seawater temperatures. Neither Symbiodinium genotypes nor densities differed between the ambient 29.5°C and 32°C. Chlorophyll a and c2 per Symbiodinium cell, however, were lower at 32°C leading to a reduction in chlorophyll content in the branches and an associated reduction in estimated absorbance and increase in the chlorophyll a specific absorption coefficient. The adjustments in the photochemical parameters led to changes in photochemical efficiencies, although these too showed that the gorgonians were coping. For example, the maximum excitation pressure, Qm, was significantly lower at 32°C than at 29.5°C. In addition, although per dry weight the amount of protein and lipids were lower at 32°C, the overall energy content in the tissues did not differ between the temperatures. Antioxidant activity either remained the same or increased following exposure to 32°C further reiterating a response that dealt with the stressor. Taken together, the capability of Caribbean gorgonian corals to modify symbiont, host

  16. Exploring the potential for actinobacteria as defensive symbionts in fungus-growing termites.

    Science.gov (United States)

    Visser, Anna A; Nobre, Tânia; Currie, Cameron R; Aanen, Duur K; Poulsen, Michael

    2012-05-01

    In fungus-growing termites, fungi of the subgenus Pseudoxylaria threaten colony health through substrate competition with the termite fungus (Termitomyces). The potential mechanisms with which termites suppress Pseudoxylaria have remained unknown. Here we explore if Actinobacteria potentially play a role as defensive symbionts against Pseudoxylaria in fungus-growing termites. We sampled for Actinobacteria from 30 fungus-growing termite colonies, spanning the three main termite genera and two geographically distant sites. Our isolations yielded 360 Actinobacteria, from which we selected subsets for morphological (288 isolates, grouped in 44 morphotypes) and for 16S rRNA (35 isolates, spanning the majority of morphotypes) characterisation. Actinobacteria were found throughout all sampled nests and colony parts and, phylogenetically, they are interspersed with Actinobacteria from origins other than fungus-growing termites, indicating lack of specificity. Antibiotic-activity screening of 288 isolates against the fungal cultivar and competitor revealed that most of the Actinobacteria-produced molecules with antifungal activity. A more detailed bioassay on 53 isolates, to test the specificity of antibiotics, showed that many Actinobacteria inhibit both Pseudoxylaria and Termitomyces, and that the cultivar fungus generally is more susceptible to inhibition than the competitor. This suggests that either defensive symbionts are not present in the system or that they, if present, represent a subset of the community isolated. If so, the antibiotics must be used in a targeted fashion, being applied to specific areas by the termites. We describe the first discovery of an assembly of antibiotic-producing Actinobacteria occurring in fungus-growing termite nests. However, due to the diversity found, and the lack of both phylogenetic and bioactivity specificity, further work is necessary for a better understanding of the putative role of antibiotic-producing bacteria in the fungus

  17. A Phase-Variable Surface Layer from the Gut Symbiont Bacteroides thetaiotaomicron.

    Science.gov (United States)

    Taketani, Mao; Donia, Mohamed S; Jacobson, Amy N; Lambris, John D; Fischbach, Michael A

    2015-09-29

    The capsule from Bacteroides, a common gut symbiont, has long been a model system for studying the molecular mechanisms of host-symbiont interactions. The Bacteroides capsule is thought to consist of an array of phase-variable polysaccharides that give rise to subpopulations with distinct cell surface structures. Here, we report the serendipitous discovery of a previously unknown surface structure in Bacteroides thetaiotaomicron: a surface layer composed of a protein of unknown function, BT1927. BT1927, which is expressed in a phase-variable manner by ~1:1,000 cells in a wild-type culture, forms a hexagonally tessellated surface layer. The BT1927-expressing subpopulation is profoundly resistant to complement-mediated killing, due in part to the BT1927-mediated blockade of C3b deposition. Our results show that the Bacteroides surface structure is capable of a far greater degree of structural variation than previously known, and they suggest that structural variation within a Bacteroides species is important for productive gut colonization. Many bacterial species elaborate a capsule, a structure that resides outside the cell wall and mediates microbe-microbe and microbe-host interactions. Species of Bacteroides, the most abundant genus in the human gut, produce a capsule that consists of an array of polysaccharides, some of which are known to mediate interactions with the host immune system. Here, we report the discovery of a previously unknown surface structure in Bacteroides thetaiotaomicron. We show that this protein-based structure is expressed by a subset of cells in a population and protects Bacteroides from killing by complement, a component of the innate immune system. This novel surface layer protein is conserved across many species of the genus Bacteroides, suggesting an important role in colonization and host immune modulation. Copyright © 2015 Taketani et al.

  18. Differential effects of copper on three species of scleractinian corals and their algal symbionts (Symbiodinium spp.).

    Science.gov (United States)

    Bielmyer, G K; Grosell, M; Bhagooli, R; Baker, A C; Langdon, C; Gillette, P; Capo, T R

    2010-04-15

    Land-based sources of pollution have been identified as significant stressors linked to the widespread declines of coral cover in coastal reef ecosystems over the last 30 years. Metal contaminants, although noted as a concern, have not been closely monitored in these sensitive ecosystems, nor have their potential impacts on coral-algal symbioses been characterized. In this study, three species of laboratory-reared scleractinian corals, Acropora cervicornis, Pocillopora damicornis, and Montastraea faveolata each containing different algal symbionts (Symbiodinium A3, C1 and D1a, respectively) were exposed to copper (ranging from 2 to 20microg/L) for 5 weeks. At the end of the exposure period, copper had accumulated in the endosymbiotic dinoflagellate ("zooxanthellae") and animal tissue of A. cervicornis and the animal tissue of M. faveolata; however, no copper accumulation was detected in the zooxanthellae or animal tissue of P. damicornis. The three coral species exhibited significantly different sensitivities to copper, with effects occurring in A. cervicornis and P. damicornis at copper concentrations as low as 4microg/L. Copper exposure affected zooxanthellae photosynthesis in A. cervicornis and P. damicornis, and carbonic anhydrase was significantly decreased in A. cervicornis and M. faveolata. Likewise, significant decreases in skeletal growth were observed in A. cervicornis and P. damicornis after copper exposure. Based on preliminary results, no changes in Symbiodinium communities were apparent in response to increasing copper concentration. These results indicate that the relationships between physiological/toxicological endpoints and copper accumulation between coral species differ, suggesting different mechanisms of toxicity and/or susceptibility. This may be driven, in part, by differences in the algal symbiont communities of the coral species in question.

  19. Burkholderia spp. are the most competitive symbionts of Mimosa, particularly under N-limited conditions.

    Science.gov (United States)

    Elliott, Geoffrey N; Chou, Jui-Hsing; Chen, Wen-Ming; Bloemberg, Guido V; Bontemps, Cyril; Martínez-Romero, Esperanza; Velázquez, Encarna; Young, J Peter W; Sprent, Janet I; James, Euan K

    2009-04-01

    Bacteria isolated from Mimosa nodules in Taiwan, Papua New Guinea, Mexico and Puerto Rico were identified as belonging to either the alpha- or beta-proteobacteria. The beta-proteobacterial Burkholderia and Cupriavidus strains formed effective symbioses with the common invasive species Mimosa diplotricha, M. pigra and M. pudica, but the alpha-proteobacterial Rhizobium etli and R. tropici strains produced a range of symbiotic phenotypes from no nodulation through ineffective to effective nodulation, depending on Mimosa species. Competition studies were performed between three of the alpha-proteobacteria (R. etli TJ167, R. tropici NGR181 and UPRM8021) and two of the beta-rhizobial symbionts (Burkholderia mimosarum PAS44 and Cupriavidus taiwanensis LMG19424) for nodulation of these invasive Mimosa species. Under flooded conditions, B. mimosarum PAS44 out-competed LMG19424 and all three alpha-proteobacteria to the point of exclusion. This advantage was not explained by initial inoculum levels, rates of bacterial growth, rhizobia-rhizobia growth inhibition or individual nodulation rate. However, the competitive domination of PAS44 over LMG19424 was reduced in the presence of nitrate for all three plant hosts. The largest significant effect was for M. pudica, in which LMG19424 formed 57% of the nodules in the presence of 0.5 mM potassium nitrate. In this host, ammonium also had a similar, but lesser, effect. Comparable results were also found using an N-containing soil mixture, and environmental N levels are therefore suggested as a factor in the competitive success of the bacterial symbiont in vivo.

  20. A Case Study of Horizontal Teacher Evaluation.

    Science.gov (United States)

    Johnson, Trav D.

    Horizontal teacher evaluation increases understanding of teaching through the critical examination of educational goals and classroom practices. This examination includes teachers' classroom observations of one another coupled with in-depth teacher conversations or dialogue about teaching aims and practices. A qualitative case study of a…

  1. Third international seminar on horizontal steam generators

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    The Third International Seminar on Horizontal Steam Generators held on October 18-20, 1994 in Lappeenranta, consisted of six sessions dealing with the topics: thermal hydraulic experiments and analyses, primary collector integrity, management of primary-to-secondary leakage accidents, feedwater collector replacement and discussion of VVER-440 steam generator safety issues.

  2. Parametric study for horizontal steam generator modelling

    Energy Technology Data Exchange (ETDEWEB)

    Ovtcharova, I. [Energoproekt, Sofia (Bulgaria)

    1995-12-31

    In the presentation some of the calculated results of horizontal steam generator PGV - 440 modelling with RELAP5/Mod3 are described. Two nodalization schemes have been used with different components in the steam dome. A study of parameters variation on the steam generator work and calculated results is made in cases with separator and branch.

  3. Evaluation of horizontal magnification on panoramic images

    Directory of Open Access Journals (Sweden)

    Maryam Raoof

    2013-01-01

    Full Text Available Aims: This study evaluated the horizontal magnification of images taken from adults and pediatrics with PM 2002 CC Planmeca analogue machine. Materials and Methods: A series of 120 panoramic radiographs were obtained of 60 adults and 60 pediatrics. For all patients, negative impressions were used to make positive casts of the teeth. A caliper was used to measure the maximum mesiodistal length of the buccal surface of all teeth except canines on both casts and radiographs. The horizontal magnification factor was calculated for incisor, premolar, and molar regions by dividing the values obtained from the casts by the values obtained from the radiographs. Statistical Analysis: Independent t-test and one-way analysis of variance (ANOVA were used. Results: The results indicated that with regard to adults, maxillary and mandibular incisor regions, unlike the other two sessions, didn′t show significant difference of the mean magnification of horizontal dimension (P = 0.5. In pediatrics, the comparison between mean magnification factors of all subgroups showed significant difference (P < 0.0001. Despite the adults′ radiographs, the results of pediatrics′ radiographs showed significantly higher magnification than the index listed by the manufacturer of the radiographic machine used. Conclusion: The present study results point to the fact that PM 2002 CC Proline panoramic machine makes possible precise measurements on radiographs of adults′ jaws in the horizontal dimension.

  4. Fermion mass hierarchy and global horizontal symmetries

    Energy Technology Data Exchange (ETDEWEB)

    Gelmini, G.B.; Gerard, J.M.; Yanagida, T.; Zoupanos, G. (European Organization for Nuclear Research, Geneva (Switzerland))

    1984-02-02

    We present a mechanism for quark mass generation in zeroth order using induced representations rather than the minimization of the horizontal potential. Using a simplicity criterion, we derive a realistic mass matrix. We also discuss a possible application of the mechanism to various models.

  5. Horizontal gene transfer in the phytosphere

    NARCIS (Netherlands)

    Elsas, van J.D.; Turner, S.; Bailey, M.J.

    2003-01-01

    Here, the ecological aspects of gene transfer processes between bacteria in the phytosphere are examined in the context of emerging evidence for the dominant role that horizontal gene transfer (HGT) has played in the evolutionary shaping of bacterial communities. Moreover, the impact of the putative

  6. Flow mapping for ESS horizontal target

    Energy Technology Data Exchange (ETDEWEB)

    Takeda, Y.; Kikura, H.; Taishi, T. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-09-01

    Flow behaviour for ESS horizontal target is studied experimentally using two dimensional water model. A velocity field of stationary flow in reaction zone has been obtained. Three dimensional effect was also studied as a spanwise flow structure. (author) 3 figs., 3 refs.

  7. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...

  8. Teaching Activities on Horizontal Nuclear Proliferation.

    Science.gov (United States)

    Zola, John

    1990-01-01

    Provides learning activities concerning the horizontal proliferation of nuclear weapons. Includes step-by-step directions for four activities: (1) the life cycle of nuclear weapons; (2) nuclear nonproliferation: pros and cons; (3) the nuclear power/nuclear weapons connection; and (4) managing nuclear proliferation. (NL)

  9. Mud and cement for horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Zurdo, C.; Georges, C.; Martin, M.

    1986-01-01

    High-angle and horizontal well bores raise many questions concerning the characteristics of mud and cement. This paper is a summary of the authors' knowledge and work on these two subjects. For all research carried out, large or full-scale laboratory test plants were used. Cutting transport is not only a problem in horizontal conditions but hole angles of 25 to 65/sup 0/ can be even more critical when parameters such as mud rheological properties and velocities are not optimized. Drilling a long horizontal drain creates a dynamic annulus pressure unbalance. This can lead to a loss and kick situation. Two test benches were thus used to obtain a good understanding of the inefficiency of conventional plugging methods and of the difficulties of gas migration control in subhorizontal well bores. High concentrations of LCM, high rheological properties of fluids and low flow rates increase the changes of solving the first problem. The results of the second bench demonstrate the difficulties of annulus gas evacution for angles varying from 90 to 100 degrees, or from over-gauged sections in horizontal holes.

  10. Survey of Transmission Cost Allocation Methodologies for Regional Transmission Organizations

    Energy Technology Data Exchange (ETDEWEB)

    Fink, S.; Porter, K.; Mudd, C.; Rogers, J.

    2011-02-01

    The report presents transmission cost allocation methodologies for reliability transmission projects, generation interconnection, and economic transmission projects for all Regional Transmission Organizations.

  11. Transmission of wild-type and recombinant HaSNPV among larvae of Helicoverpa armigera (Lepidoptera: Noctuidae) on cotton.

    NARCIS (Netherlands)

    Georgievska, L.; Vries, R.S.M.; Gao, P.; Sun, X.; Cory, J.S.; Vlak, J.M.; Werf, van der W.

    2010-01-01

    Horizontal transmission of insect viruses is a key factor in their cycling in agro-ecosystems. Here we study the transmission of the baculovirus HaSNPV among larvae of Helicoverpa armigera (Hübner) in cotton. Transmission of three HaSNPV genotypes was studied from larvae infected with a single virus

  12. The extrasolar planet atmosphere and exosphere: Emission and transmission spectroscopy

    CERN Document Server

    Tinetti, Giovanna

    2008-01-01

    We have entered the phase of extrasolar planets characterization, probing their atmospheres for molecules, constraining their horizontal and vertical temperature profiles and estimating the contribution of clouds and hazes. We report here a short review of the current situation using ground based and space based observations, and present the transmission spectra of HD189733b in the spectral range 0.5-24 microns.

  13. Horizontal transfer of bacterial polyphosphate kinases to eukaryotes: implications for the ice age and land colonisation.

    Science.gov (United States)

    Whitehead, Michael P; Hooley, Paul; W Brown, Michael R

    2013-06-05

    Studies of online database(s) showed that convincing examples of eukaryote PPKs derived from bacteria type PPK1 and PPK2 enzymes are rare and currently confined to a few simple eukaryotes. These enzymes probably represent several separate horizontal transfer events. Retention of such sequences may be an advantage for tolerance to stresses such as desiccation or nutrient depletion for simple eukaryotes that lack more sophisticated adaptations available to multicellular organisms. We propose that the acquisition of encoding sequences for these enzymes by horizontal transfer enhanced the ability of early plants to colonise the land. The improved ability to sequester and release inorganic phosphate for carbon fixation by photosynthetic algae in the ocean may have accelerated or even triggered global glaciation events. There is some evidence for DNA sequences encoding PPKs in a wider range of eukaryotes, notably some invertebrates, though it is unclear that these represent functional genes.Polyphosphate (poly P) is found in all cells, carrying out a wide range of essential roles. Studied mainly in prokaryotes, the enzymes responsible for synthesis of poly P in eukaryotes (polyphosphate kinases PPKs) are not well understood. The best characterised enzyme from bacteria known to catalyse the formation of high molecular weight polyphosphate from ATP is PPK1 which shows some structural similarity to phospholipase D. A second bacterial PPK (PPK2) resembles thymidylate kinase. Recent reports have suggested a widespread distribution of these bacteria type enzymes in eukaryotes. On - line databases show evidence for the presence of genes encoding PPK1 in only a limited number of eukaryotes. These include the photosynthetic eukaryotes Ostreococcus tauri, O. lucimarinus, Porphyra yezoensis, Cyanidioschyzon merolae and the moss Physcomitrella patens, as well as the amoeboid symbiont Capsaspora owczarzaki and the non-photosynthetic eukaryotes Dictyostelium (3 species

  14. Determinants of Arbovirus Vertical Transmission in Mosquitoes.

    Science.gov (United States)

    Lequime, Sebastian; Paul, Richard E; Lambrechts, Louis

    2016-05-01

    Vertical transmission (VT) and horizontal transmission (HT) of pathogens refer to parental and non-parental chains of host-to-host transmission. Combining HT with VT enlarges considerably the range of ecological conditions in which a pathogen can persist, but the factors governing the relative frequency of each transmission mode are poorly understood for pathogens with mixed-mode transmission. Elucidating these factors is particularly important for understanding the epidemiology of arthropod-borne viruses (arboviruses) of public health significance. Arboviruses are primarily maintained by HT between arthropod vectors and vertebrate hosts in nature, but are occasionally transmitted vertically in the vector population from an infected female to her offspring, which is a proposed maintenance mechanism during adverse conditions for HT. Here, we review over a century of published primary literature on natural and experimental VT, which we previously assembled into large databases, to identify biological factors associated with the efficiency of arbovirus VT in mosquito vectors. Using a robust statistical framework, we highlight a suite of environmental, taxonomic, and physiological predictors of arbovirus VT. These novel insights contribute to refine our understanding of strategies employed by arboviruses to persist in the environment and cause substantial public health concern. They also provide hypotheses on the biological processes underlying the relative VT frequency for pathogens with mixed-mode transmission that can be tested empirically.

  15. Determinants of Arbovirus Vertical Transmission in Mosquitoes.

    Directory of Open Access Journals (Sweden)

    Sebastian Lequime

    2016-05-01

    Full Text Available Vertical transmission (VT and horizontal transmission (HT of pathogens refer to parental and non-parental chains of host-to-host transmission. Combining HT with VT enlarges considerably the range of ecological conditions in which a pathogen can persist, but the factors governing the relative frequency of each transmission mode are poorly understood for pathogens with mixed-mode transmission. Elucidating these factors is particularly important for understanding the epidemiology of arthropod-borne viruses (arboviruses of public health significance. Arboviruses are primarily maintained by HT between arthropod vectors and vertebrate hosts in nature, but are occasionally transmitted vertically in the vector population from an infected female to her offspring, which is a proposed maintenance mechanism during adverse conditions for HT. Here, we review over a century of published primary literature on natural and experimental VT, which we previously assembled into large databases, to identify biological factors associated with the efficiency of arbovirus VT in mosquito vectors. Using a robust statistical framework, we highlight a suite of environmental, taxonomic, and physiological predictors of arbovirus VT. These novel insights contribute to refine our understanding of strategies employed by arboviruses to persist in the environment and cause substantial public health concern. They also provide hypotheses on the biological processes underlying the relative VT frequency for pathogens with mixed-mode transmission that can be tested empirically.

  16. Murine gammaherpesvirus-68 (MHV-68) is not horizontally transmitted amongst laboratory mice by cage contact.

    Science.gov (United States)

    Aligo, Jason; Brosnan, Kerry; Walker, Mindi; Emmell, Eva; Mikkelsen, S Rochelle; Burleson, Gary R; Burleson, Florence G; Volk, Amy; Weinstock, Daniel

    2015-01-01

    Murine gammaherpesvirus-68 (MHV-68), a natural pathogen of mice, is being evaluated as a model of Epstein Barr Virus (EBV) infection for use in investigation of the effects of immunomodulatory therapy on herpesvirus pathogenesis in humans. Immunosuppressive agents are used for treatment of a variety of autoimmune diseases as well as for prevention of tissue rejection after organ transplantation and can result in recrudescence of latent herpesvirus infections. Prior to examination of MHV-68 as a suitable model for EBV, better characterization of the MHV-68 model was desirable. Characterization of the MHV-68 model involved development of assays for detecting virus and for demonstration of safety when present in murine colonies. Limited information is available in the literature regarding MHV-68 transmission, although recent reports indicate the virus is not horizontally spread in research facilities. To further determine transmission potential, immunocompetent and immunodeficient mice were infected with MHV-68 and co-habitated with naïve animals. Molecular pathology assays were developed to characterize the MHV-68 model and to determine viral transmission. Horizontal transmission of virus was not observed from infected animals to naïve cagemates after fluorescence microscopy assays and quantitative PCR (qPCR). Serologic analysis complemented these studies and was used as a method of monitoring infection amongst murine colonies. Overall, these findings demonstrate that MHV-68 infection can be controlled and monitored in murine research facilities, and the potential for unintentional infection is low.

  17. Interplay between Endophyte Prevalence, Effects and Transmission: Insights from a Natural Grass Population.

    Science.gov (United States)

    Gibert, Anaïs; Magda, Danièle; Hazard, Laurent

    2015-01-01

    Two main mechanisms are thought to affect the prevalence of endophyte-grass symbiosis in host populations: the mode of endophyte transmission, and the fitness differential between symbiotic and non-symbiotic plants. These mechanisms have mostly been studied in synthetic grass populations. If we are to improve our understanding of the ecological and evolutionary dynamics of such symbioses, we now need to determine the combinations of mechanisms actually operating in the wild, in populations shaped by evolutionary history. We used a demographic population modeling approach to identify the mechanisms operating in a natural stand of an intermediate population (i.e. 50% of plants symbiotic) of the native grass Festuca eskia. We recorded demographic data in the wild over a period of three years, with manipulation of the soil resources for half the population. We developed two stage-structured matrix population models. The first model concerned either symbiotic or non-symbiotic plants. The second model included both symbiotic and non-symbiotic plants and took endophyte transmission rates into account. According to our models, symbiotic had a significantly higher population growth rate than non-symbiotic plants, and endophyte prevalence was about 58%. Endophyte transmission rates were about 0.67 or 0.87, depending on the growth stage considered. In the presence of nutrient supplementation, population growth rates were still significantly higher for symbiotic than for non-symbiotic plants, but endophyte prevalence fell to 0%. At vertical transmission rates below 0.10-0.20, no symbiosis was observed. Our models showed that a positive benefit of the endophyte and vertical transmission rates of about 0.6 could lead to the coexistence of symbiotic and non-symbiotic F. eskia plants. The positive effect of the symbiont on host is not systematically associated with high transmission rates of the symbiont over short time scales, in particular following an environmental change.

  18. The origin of the chemical profiles of fungal symbionts and their significance for nestmate recognition in Acromyrmex leaf-cutting ants

    DEFF Research Database (Denmark)

    Richard, Freddie-Jeanne; Poulsen, Michael; Hefetz, Abraham;

    2007-01-01

    Cuticular hydrocarbon profiles are essential for nestmate recognition in insect societies, and quantitative variation in these recognition cues is both environmentally and genetically determined. Environmental cues are normally derived from food or nest material, but an exceptional situation may...... significantly with amides, aldehydes, and methyl esters contributing to the correlations, but acetates, alkanes, and formates being unrelated to genetic variation among symbionts. We show experimentally that workers that are previously exposed to and fed with the fungal symbiont of another colony are met...

  19. Characteristics of Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Li, Zhigang

    and smoke. Air flow through vertical openings has been widely investigated but little is known about the flow in the horizontal openings, especially when they are driven by buoyancy. A literature survey shows that the brine-water system and the scale model are normally used forthe research work of air flow...... through horizontal openings. Two cases of full-scale measurements of buoyancy driven natural ventilation through horizontal openings are performed: one horizontal opening and one horizontal opening combined with one vertical opening. For the case of one horizontal opening, the measurements are made...

  20. The horizontal plane appearances of scoliosis

    DEFF Research Database (Denmark)

    Illés, Tamás S.; Burkus, Máté; Somoskeőy, Szabolcs

    2017-01-01

    Purpose: A posterior-anterior vertebral vector is proposed to facilitate visualization and understanding of scoliosis. The aim of this study was to highlight the interest of using vertebral vectors, especially in the horizontal plane, in clinical practice. Methods: We used an EOS two-/three-dimen......Purpose: A posterior-anterior vertebral vector is proposed to facilitate visualization and understanding of scoliosis. The aim of this study was to highlight the interest of using vertebral vectors, especially in the horizontal plane, in clinical practice. Methods: We used an EOS two...... of scoliosis. The approach used is simple. These results are sufficient for a first visual analysis furnishing significant clinical information in all three anatomical planes. This visualization represents a reasonable compromise between mathematical purity and practical use....

  1. Kinematics of horizontal and vertical caterpillar crawling.

    Science.gov (United States)

    van Griethuijsen, Linnea I; Trimmer, Barry A

    2009-05-01

    Unlike horizontal crawling, vertical crawling involves two counteracting forces: torque rotating the body around its center of mass and gravity resisting forward movement. The influence of these forces on kinematics has been examined in the soft-bodied larval stage of Manduca sexta. We found that crawling and climbing are accomplished using the same movements, with both segment timing and proleg lift indistinguishable in horizontal and vertical locomotion. Minor differences were detected in stride length and in the delay between crawls, which led to a lower crawling speed in the vertical orientation. Although these differences were statistically significant, they were much smaller than the variation in kinematic parameters between animals. The ability of Manduca to crawl and climb using the same movements is best explained by Manduca's relatively small size, slow speed and strong, controlled, passive grip made possible by its proleg/crochets.

  2. Detecting series periodicity with horizontal visibility graphs

    CERN Document Server

    Núñez, Angel M; Valero, Eusebio; Gómez, Jose Patricio; Luque, Bartolo

    2011-01-01

    The horizontal visibility algorithm has been recently introduced as a mapping between time series and networks. The challenge lies in characterizing the structure of time series (and the processes that generated those series) using the powerful tools of graph theory. Recent works have shown that the visibility graphs inherit several degrees of correlations from their associated series, and therefore such graph theoretical characterization is in principle possible. However, both the mathematical grounding of this promising theory and its applications are on its infancy. Following this line, here we address the question of detecting hidden periodicity in series polluted with a certain amount of noise. We first put forward some generic properties of horizontal visibility graphs which allow us to define a (graph theoretical) noise reduction filter. Accordingly, we evaluate its performance for the task of calculating the period of noisy periodic signals, and compare our results with standard time domain (autocorre...

  3. Buoyancy Driven Natural Ventilation through Horizontal Openings

    DEFF Research Database (Denmark)

    Heiselberg, Per; Li, Zhigang

    2009-01-01

    An experimental study of the phenomenon of buoyancy driven natural ventilation through single-sided horizontal openings was performed in a full-scale laboratory test rig. The measurements were made for opening ratios L/D ranging from 0.027 to 4.455, where L and D are the length of the opening...... and the diameter of the opening, respectively. The basic nature of airflow through single-sided openings, including airflow rate, air velocity, temperature difference between the rooms and the dimensions of the horizontal openings, were measured. A bi-directional airflow rate was measured using the constant...... injection tracer gas technique. Smoke visualizations showed that the airflow patterns are highly transient and unstable, and that the airflow rate oscillates with time. Correlations between the Froude (Archimedes) number Fr (Ar) and the L/D ratio are presented. In some cases the measured airflow rates fit...

  4. Horizontal Bilayer for Electrical and Optical Recordings

    Directory of Open Access Journals (Sweden)

    Alf Honigmann

    2012-12-01

    Full Text Available Artificial bilayer containing reconstituted ion channels, transporters and pumps serve as a well-defined model system for electrophysiological investigations of membrane protein structure–function relationship. Appropriately constructed microchips containing horizontally oriented bilayers with easy solution access to both sides provide, in addition, the possibility to investigate these model bilayer membranes and the membrane proteins therein with high resolution fluorescence techniques up to the single-molecule level. Here, we describe a bilayer microchip system in which long-term stable horizontal free-standing and hydrogel-supported bilayers can be formed and demonstrate its prospects particularly for single-molecule fluorescence spectroscopy and high resolution fluorescence microscopy in probing the physicochemical properties like phase behavior of the bilayer-forming lipids, as well as in functional studies of membrane proteins.

  5. Gas reservoir evaluation for underbalanced horizontal drilling

    Directory of Open Access Journals (Sweden)

    Li Gao

    2014-01-01

    Full Text Available A set of surface equipment for monitoring the parameters of fluid and pressure while drilling was developed, and mathematical models for gas reservoir seepage and wellbore two-phase flow were established. Based on drilling operation parameters, well structure and monitored parameters, the wellbore pressure and the gas reservoir permeability could be predicted theoretically for underbalanced horizontal drilling. Based on the monitored gas production along the well depth, the gas reservoir type could be identified.

  6. Horizontal Symmetry: Bottom Up and Top Down

    CERN Document Server

    Lam, C S

    2011-01-01

    A group-theoretical connection between horizontal symmetry $\\G$ and fermion mixing is established, and applied to neutrino mixing. The group-theoretical approach is consistent with a dynamical theory based on $U(1)\\times \\G$, but the dynamical theory can be used to pick out the most stable mixing that purely group-theoretical considerations cannot. A symmetry common to leptons and quarks is also discussed. This higher symmetry picks $A_4$ over $S_4$ to be the preferred symmetry for leptons.

  7. Convection in horizontally shaken granular material

    OpenAIRE

    Saluena, Clara; Poeschel, Thorsten

    1998-01-01

    In horizontally shaken granular material different types of pattern formation have been reported. We want to deal with the convection instability which has been observed in experiments and which recently has been investigated numerically. Using two dimensional molecular dynamics we show that the convection pattern depends crucial on the inelastic properties of the material. The concept of restitution coefficient provides arguments for the change of the behaviour with variing inelasticity.

  8. R&D investments fostering horizontal mergers

    OpenAIRE

    Cabolis, C.; Manasakis, C.; MORENO, Diego; Petrakis, Emmanuel

    2016-01-01

    We study a homogenous good triopoly in which firms first choose their cost-reducing R&D investments and consider alternative merger proposals, and then compete à la Cournot in the ensuing industry. We identify conditions under which both horizontal mergers and non integration are sustained by Coalition-Proof Nash equilibria (CPNE). These conditions involve the effectiveness of the R&D technology, as well as the distribution of the bargaining power between the acquirer and the acquiree, which ...

  9. Thermal transient analysis applied to horizontal wells

    Energy Technology Data Exchange (ETDEWEB)

    Duong, A.N. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[ConocoPhillips Canada Resources Corp., Calgary, AB (Canada)

    2008-10-15

    Steam assisted gravity drainage (SAGD) is a thermal recovery process used to recover bitumen and heavy oil. This paper presented a newly developed model to estimate cooling time and formation thermal diffusivity by using a thermal transient analysis along the horizontal wellbore under a steam heating process. This radial conduction heating model provides information on the heat influx distribution along a horizontal wellbore or elongated steam chamber, and is therefore important for determining the effectiveness of the heating process in the start-up phase in SAGD. Net heat flux estimation in the target formation during start-up can be difficult to measure because of uncertainties regarding heat loss in the vertical section; steam quality along the horizontal segment; distribution of steam along the wellbore; operational conditions; and additional effects of convection heating. The newly presented model can be considered analogous to pressure transient analysis of a buildup after a constant pressure drawdown. The model is based on an assumption of an infinite-acting system. This paper also proposed a new concept of a heating ring to measure the heat storage in the heated bitumen at the time of testing. Field observations were used to demonstrate how the model can be used to save heat energy, conserve steam and enhance bitumen recovery. 18 refs., 14 figs., 2 appendices.

  10. Vertical and horizontal seismometric observations of tides

    Science.gov (United States)

    Lambotte, S.; Rivera, L.; Hinderer, J.

    2006-01-01

    Tidal signals have been largely studied with gravimeters, strainmeters and tiltmeters, but can also be retrieved from digital records of the output of long-period seismometers, such as STS-1, particularly if they are properly isolated. Horizontal components are often noisier than the vertical ones, due to sensitivity to tilt at long periods. Hence, horizontal components are often disturbed by local effects such as topography, geology and cavity effects, which imply a strain-tilt coupling. We use series of data (duration larger than 1 month) from several permanent broadband seismological stations to examine these disturbances. We search a minimal set of observable signals (tilts, horizontal and vertical displacements, strains, gravity) necessary to reconstruct the seismological record. Such analysis gives a set of coefficients (per component for each studied station), which are stable over years and then can be used systematically to correct data from these disturbances without needing heavy numerical computation. A special attention is devoted to ocean loading for stations close to oceans (e.g. Matsushiro station in Japon (MAJO)), and to pressure correction when barometric data are available. Interesting observations are made for vertical seismometric components; in particular, we found a pressure admittance between pressure and data 10 times larger than for gravimeters for periods larger than 1 day, while this admittance reaches the usual value of -3.5 nm/s 2/mbar for periods below 3 h. This observation may be due to instrumental noise, but the exact mechanism is not yet understood.

  11. The first engagement of partners in the Euprymna scolopes-Vibrio fischeri symbiosis is a two-step process initiated by a few environmental symbiont cells.

    Science.gov (United States)

    Altura, Melissa A; Heath-Heckman, Elizabeth A C; Gillette, Amani; Kremer, Natacha; Krachler, Anne-Marie; Brennan, Caitlin; Ruby, Edward G; Orth, Kim; McFall-Ngai, Margaret J

    2013-11-01

    We studied the Euprymna scolopes-Vibrio fischeri symbiosis to characterize, in vivo and in real time, the transition between the bacterial partner's free-living and symbiotic life styles. Previous studies using high inocula demonstrated that environmental V. fischeri cells aggregate during a 3 h period in host-shed mucus along the light organ's superficial ciliated epithelia. Under lower inoculum conditions, similar to the levels of symbiont cells in the environment, this interaction induces haemocyte trafficking into these tissues. Here, in experiments simulating natural conditions, microscopy revealed that at 3 h following first exposure, only ∼ 5 V. fischeri cells aggregated on the organ surface. These cells associated with host cilia and induced haemocyte trafficking. Symbiont viability was essential and mutants defective in symbiosis initiation and/or production of certain surface features, including the Mam7 protein, which is implicated in host cell attachment of V. cholerae, associated normally with host cilia. Studies with exopolysaccharide mutants, which are defective in aggregation, suggest a two-step process of V. fischeri cell engagement: association with host cilia followed by aggregation, i.e. host cell-symbiont interaction with subsequent symbiont-symbiont cell interaction. Taken together, these data provide a new model of early partner engagement, a complex model of host-symbiont interaction with exquisite sensitivity. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  12. Recovery from bleaching is mediated by threshold densities of background thermo-tolerant symbiont types in a reef-building coral.

    Science.gov (United States)

    Bay, Line K; Doyle, Jason; Logan, Murray; Berkelmans, Ray

    2016-06-01

    Sensitive molecular analyses show that most corals host a complement of Symbiodinium genotypes that includes thermo-tolerant types in low abundance. While tolerant symbiont types are hypothesized to facilitate tolerance to temperature and recovery from bleaching, empirical data on their distribution and relative abundance in corals under ambient and stress conditions are still rare. We quantified visual bleaching and mortality of coral hosts, along with relative abundance of C- and D-type Symbiodinium cells in 82 Acropora millepora colonies from three locations on the Great Barrier Reef transplanted to a central inshore site over a 13 month period. Our analyses reveal dynamic change in symbiont associations within colonies and among populations over time. Coral bleaching and declines in C- but not D-type symbionts were observed in transplanted corals. Survival and recovery of 25% of corals from one population was associated with either initial D-dominance or an increase in D-type symbionts that could be predicted by a minimum pre-stress D : C ratio of 0.003. One-third of corals from this population became D dominated at the bleached stage despite no initial detection of this symbiont type, but failed to recover and died in mid to late summer. These results provide a predictive threshold minimum density of background D-type symbionts in A. millepora, above which survival following extreme thermal stress is increased.

  13. Integrative study of a new cold-seep mussel (Mollusca: Bivalvia) associated with chemosynthetic symbionts in the Marmara Sea

    Science.gov (United States)

    Ritt, Bénédicte; Duperron, Sébastien; Lorion, Julien; Sara Lazar, Cassandre; Sarrazin, Jozée

    2012-09-01

    Recently, small Idas-like mussels have been discovered living on carbonate crusts associated with cold-seeps in the Marmara Sea. These mussels, here referred to as Idas-like nov. sp., differ morphologically and genetically from another species identified as Idas aff. modiolaeformis, living in the same type of ecosystem in the Nile Deep-Sea Fan (eastern Mediterranean Sea). A phylogenetic analysis confirms the distinction between the two species, which belong to highly divergent lineages. Carbon stable isotope values, as well as the detection of thiotroph-related bacteria in the gill tissue, support the presence of a symbiotic, thiotroph-derived nutrition. In contrast, Idas aff. modiolaeformis displays six different types of symbionts. Finally our size-frequency data suggest that the recruitment is continuous in the examined area. The present study extends the documented distribution of symbiont-bearing mussels to the Marmara Sea, and contributes to the characterisation of biological communities in this recently explored area.

  14. The dominant detritus-feeding invertebrate in Arctic peat soils derives its essential amino acids from gut symbionts

    DEFF Research Database (Denmark)

    Larsen, Thomas; Ventura, Marc; Maraldo, Kristine

    2016-01-01

    for EAA supplementation because almost all belong to clades capable of biosynthesizing EAA. 5. Our study provides the first evidence of extensive symbiotic supplementation of EAA by microbial gut symbionts and demonstrates that symbiotic bacteria in the gut lumen appear to function as partners both...... insufficiencies of macronutrients such as essential amino acids (EAA). Documenting whether gut symbionts also function as partners for symbiotic EAA supplementation is important because the question of how some detritivores are able to subsist on nutritionally insufficient diets has remained unresolved. 3...... of amino acids to bacteria, fungi and plants in enchytraeids. 4. Enchytraeids collected from Arctic peatlands derived more than 80% of their EAA from bacteria. In a controlled feeding study with the enchytraeid Enchytraeus crypticus, EAA derived almost exclusively from gut bacteria when the worms fed...

  15. Microsensor studies of photosynthesis and respiration in the larger symbiont bearing foraminifera Amphistegina lobifera, and Amphisorus hemprichii

    DEFF Research Database (Denmark)

    Köhler-Rink, S.; Kühl, Michael

    2001-01-01

    The photosynthesis and respiration of the larger foraminifera Amphistegina lobifera and Amphisorus hemprichii was studied with O2, CO2, and pH microsensors, and with a miniature gas exchange chamber. The diffusive transport of O2 and CO2 through both perforate (A. lobifera) and imperforate (A...... ratio at the shell surface of the foraminifera was ~2 in darkness and ~6 at saturating irradiance, pointing to a large internal supply of CO2 in the host-symbiont association and the use of bicarbonate as source for inorganic carbon. The carbonate chemistry in the vicinity of symbiont-bearing larger...... foraminifera is thus strongly affected by the combined action of photosynthesis, respiration and calcification, and cannot be considered in equilibrium with the surrounding sea water. This has important implications for paleoenvironmental analysis and interpretation of the stable isotope composition...

  16. Stringent Expression Control of Pathogenic R-body Production in Legume Symbiont Azorhizobium caulinodans.

    Science.gov (United States)

    Matsuoka, Jun-Ichi; Ishizuna, Fumiko; Kurumisawa, Keigo; Morohashi, Kengo; Ogawa, Tetsuhiro; Hidaka, Makoto; Saito, Katsuharu; Ezawa, Tatsuhiro; Aono, Toshihiro

    2017-07-25

    R bodies are insoluble large polymers consisting of small proteins encoded by reb genes and are coiled into cylindrical structures in bacterial cells. They were first discovered in Caedibacter species, which are obligate endosymbionts of paramecia. Caedibacter confers a killer trait on the host paramecia. R-body-producing symbionts are released from their host paramecia and kill symbiont-free paramecia after ingestion. The roles of R bodies have not been explained in bacteria other than CaedibacterAzorhizobium caulinodans ORS571, a microsymbiont of the legume Sesbania rostrata, carries a reb operon containing four reb genes that are regulated by the repressor PraR. Herein, deletion of the praR gene resulted in R-body formation and death of host plant cells. The rebR gene in the reb operon encodes an activator. Three PraR binding sites and a RebR binding site are present in the promoter region of the reb operon. Expression analyses using strains with mutations within the PraR binding site and/or the RebR binding site revealed that PraR and RebR directly control the expression of the reb operon and that PraR dominantly represses reb expression. Furthermore, we found that the reb operon is highly expressed at low temperatures and that 2-oxoglutarate induces the expression of the reb operon by inhibiting PraR binding to the reb promoter. We conclude that R bodies are toxic not only in paramecium symbiosis but also in relationships between other bacteria and eukaryotic cells and that R-body formation is controlled by environmental factors.IMPORTANCECaedibacter species, which are obligate endosymbiotic bacteria of paramecia, produce R bodies, and R-body-producing endosymbionts that are released from their hosts are pathogenic to symbiont-free paramecia. Besides Caedibacter species, R bodies have also been observed in a few free-living bacteria, but the significance of R-body production in these bacteria is still unknown. Recent advances in genome sequencing technologies

  17. Reciprocal immune benefit based on complementary production of antibiotics by the leech Hirudo verbana and its gut symbiont Aeromonas veronii

    OpenAIRE

    Aurélie Tasiemski; François Massol; Virginie Cuvillier-Hot; Céline Boidin-Wichlacz; Emmanuel Roger; Franck Rodet; Isabelle Fournier; Frédéric Thomas; Michel Salzet

    2015-01-01

    International audience; The medicinal leech has established a long-term mutualistic association with Aeromonas veronii, a versatile bacterium which can also display free-living waterborne and fish-or human-pathogenic lifestyles. Here, we investigated the role of antibiotics in the dynamics of interaction between the leech and its gut symbiont Aeromonas. By combining biochemical and molecular approaches, we isolated and identified for the first time the antimicrobial peptides (AMPs) produced b...

  18. Host–symbiont recombination versus natural selection in the response of coral–dinoflagellate symbioses to environmental disturbance

    Science.gov (United States)

    LaJeunesse, Todd C.; Smith, Robin; Walther, Mariana; Pinzón, Jorge; Pettay, Daniel T.; McGinley, Michael; Aschaffenburg, Matthew; Medina-Rosas, Pedro; Cupul-Magaña, Amilcar L.; Pérez, Andrés López; Reyes-Bonilla, Hector; Warner, Mark E.

    2010-01-01

    Mutualisms between reef-building corals and endosymbiotic dinoflagellates are particularly sensitive to environmental stress, yet the ecosystems they construct have endured major oscillations in global climate. During the winter of 2008, an extreme cold-water event occurred in the Gulf of California that bleached corals in the genus Pocillopora harbouring a thermally ‘sensitive’ symbiont, designated Symbiodinium C1b-c, while colonies possessing Symbiodinium D1 were mostly unaffected. Certain bleached colonies recovered quickly while others suffered partial or complete mortality. In most colonies, no appreciable change was observed in the identity of the original symbiont, indicating that these partnerships are stable. During the initial phases of recovery, a third species of symbiont B1Aiptasia, genetically identical to that harboured by the invasive anemone, Aiptasia sp., grew opportunistically and was visible as light-yellow patches on the branch tips of several colonies. However, this symbiont did not persist and was displaced in all cases by C1b-c several months later. Colonies with D1 were abundant at inshore habitats along the continental eastern Pacific, where seasonal turbidity is high relative to offshore islands. Environmental conditions of the central and southern coasts of Mexico were not sufficient to explain the exclusivity of D1 Pocillopora in these regions. It is possible that mass mortalities associated with major thermal disturbances during the 1997–1998 El Niño Southern Oscillation eliminated C1b-c holobionts from these locations. The differential loss of Pocillopora holobionts in response to thermal stress suggests that natural selection on existing variation can cause rapid and significant shifts in the frequency of particular coral–algal partnerships. However, coral populations may take decades to recover following episodes of severe selection, thereby raising considerable uncertainty about the long-term viability of these communities

  19. Potential costs of acclimatization to a warmer climate: growth of a reef coral with heat tolerant vs. sensitive symbiont types.

    Science.gov (United States)

    Jones, Alison; Berkelmans, Ray

    2010-05-03

    One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae) genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 or thermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type D zooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change.

  20. Potential costs of acclimatization to a warmer climate: growth of a reef coral with heat tolerant vs. sensitive symbiont types.

    Directory of Open Access Journals (Sweden)

    Alison Jones

    Full Text Available One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 or thermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type D zooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change.

  1. Detection and decay rates of prey and prey symbionts in the gut of a predator through metagenomics.

    Science.gov (United States)

    Paula, Débora P; Linard, Benjamin; Andow, David A; Sujii, Edison R; Pires, Carmen S S; Vogler, Alfried P

    2015-07-01

    DNA methods are useful to identify ingested prey items from the gut of predators, but reliable detection is hampered by low amounts of degraded DNA. PCR-based methods can retrieve minute amounts of starting material but suffer from amplification biases and cross-reactions with the predator and related species genomes. Here, we use PCR-free direct shotgun sequencing of total DNA isolated from the gut of the harlequin ladybird Harmonia axyridis at five time points after feeding on a single pea aphid Acyrthosiphon pisum. Sequence reads were matched to three reference databases: Insecta mitogenomes of 587 species, including H. axyridis sequenced here; A. pisum nuclear genome scaffolds; and scaffolds and complete genomes of 13 potential bacterial symbionts. Immediately after feeding, multicopy mtDNA of A. pisum was detected in tens of reads, while hundreds of matches to nuclear scaffolds were detected. Aphid nuclear DNA and mtDNA decayed at similar rates (0.281 and 0.11 h(-1) respectively), and the detectability periods were 32.7 and 23.1 h. Metagenomic sequencing also revealed thousands of reads of the obligate Buchnera aphidicola and facultative Regiella insecticola aphid symbionts, which showed exponential decay rates significantly faster than aphid DNA (0.694 and 0.80 h(-1) , respectively). However, the facultative aphid symbionts Hamiltonella defensa, Arsenophonus spp. and Serratia symbiotica showed an unexpected temporary increase in population size by 1-2 orders of magnitude in the predator guts before declining. Metagenomics is a powerful tool that can reveal complex relationships and the dynamics of interactions among predators, prey and their symbionts.

  2. Diversity of fatty acid composition of symbiotic dinoflagellates in corals: evidence for the transfer of host PUFAs to the symbionts.

    Science.gov (United States)

    Imbs, Andrey B; Yakovleva, Irina M; Dautova, Tatiana N; Bui, Long H; Jones, Paul

    2014-05-01

    High diversity of fatty acid (FA) composition of endosymbiotic dinoflagellates of the Symbiodinium group (zooxanthellae) isolated from different cnidarian groups has been found. To explain this diversity, FA composition of the total lipids of pure symbiont fractions (SF) and host cell tissue fractions (HF) isolated from one hydrocoral, two soft coral, and seven hard coral species inhabiting the shallow waters of the South China Sea (Vietnam) were compared. Symbiodinium phylogenetic clade designation for each SF was also determined, however, the relationship between the clade designation and FA composition of Symbiodinium was not found. The profiles of marker polyunsaturated FAs (PUFAs) of symbionts (18:4n-3, 18:5n-3, 20:5n-3) did not depend on taxonomic designation of the host and reflected only a specimen-specific diversity of the SF lipids. Several FAs such as 20:0, C24 PUFAs, 22:5n-6, and 18:2n-7 concentrated in HF lipids but were also found in SF lipids. For ten cnidarian species studied, the principal components analysis of total FAs (27 variables) of the symbiotic fractions was performed. The clear division of the symbiotic dinoflagellates according to the host systematic identity was found on a subclass level. This division was mainly caused by the FAs specific for the host lipids of each cnidarian subclasses such as hard corals, soft corals, and hydrocorals. Thus, the coral hosts affect the FA profile of their symbionts and cause the diversity of FA composition of Symbiodinium. The transfer of FAs from the coral host to their symbiotic dinoflagellates and modulation of PUFA biosynthesis in symbionts by the host are considered as possible reasons of the diversity studied.

  3. Coral bleaching under thermal stress: putative involvement of host/symbiont recognition mechanisms

    Directory of Open Access Journals (Sweden)

    Tambutte Sylvie

    2009-08-01

    Full Text Available Abstract Background Coral bleaching can be defined as the loss of symbiotic zooxanthellae and/or their photosynthetic pigments from their cnidarian host. This major disturbance of reef ecosystems is principally induced by increases in water temperature. Since the beginning of the 1980s and the onset of global climate change, this phenomenon has been occurring at increasing rates and scales, and with increasing severity. Several studies have been undertaken in the last few years to better understand the cellular and molecular mechanisms of coral bleaching but the jigsaw puzzle is far from being complete, especially concerning the early events leading to symbiosis breakdown. The aim of the present study was to find molecular actors involved early in the mechanism leading to symbiosis collapse. Results In our experimental procedure, one set of Pocillopora damicornis nubbins was subjected to a gradual increase of water temperature from 28°C to 32°C over 15 days. A second control set kept at constant temperature (28°C. The differentially expressed mRNA between the stressed states (sampled just before the onset of bleaching and the non stressed states (control were isolated by Suppression Subtractive Hybridization. Transcription rates of the most interesting genes (considering their putative function were quantified by Q-RT-PCR, which revealed a significant decrease in transcription of two candidates six days before bleaching. RACE-PCR experiments showed that one of them (PdC-Lectin contained a C-Type-Lectin domain specific for mannose. Immunolocalisation demonstrated that this host gene mediates molecular interactions between the host and the symbionts suggesting a putative role in zooxanthellae acquisition and/or sequestration. The second gene corresponds to a gene putatively involved in calcification processes (Pdcyst-rich. Its down-regulation could reflect a trade-off mechanism leading to the arrest of the mineralization process under stress

  4. Ancestral genetic diversity associated with the rapid spread of stress-tolerant coral symbionts in response to Holocene climate change.

    Science.gov (United States)

    Hume, Benjamin C C; Voolstra, Christian R; Arif, Chatchanit; D'Angelo, Cecilia; Burt, John A; Eyal, Gal; Loya, Yossi; Wiedenmann, Jörg

    2016-04-19

    Coral communities in the Persian/Arabian Gulf (PAG) withstand unusually high salinity levels and regular summer temperature maxima of up to ∼35 °C that kill conspecifics elsewhere. Due to the recent formation of the PAG and its subsequent shift to a hot climate, these corals have had only adapt to these extreme conditions and can therefore inform on how coral reefs may respond to global warming. One key to coral survival in the world's warmest reefs are symbioses with a newly discovered alga,Symbiodinium thermophilum Currently, it is unknown whether this symbiont originated elsewhere or emerged from unexpectedly fast evolution catalyzed by the extreme environment. Analyzing genetic diversity of symbiotic algae across >5,000 km of the PAG, the Gulf of Oman, and the Red Sea coastline, we show thatS. thermophilumis a member of a highly diverse, ancient group of symbionts cryptically distributed outside the PAG. We argue that the adjustment to temperature extremes by PAG corals was facilitated by the positive selection of preadapted symbionts. Our findings suggest that maintaining the largest possible pool of potentially stress-tolerant genotypes by protecting existing biodiversity is crucial to promote rapid adaptation to present-day climate change, not only for coral reefs, but for ecosystems in general.

  5. Quantification of bacterial and archaeal symbionts in high and low microbial abundance sponges using real-time PCR

    KAUST Repository

    Bayer, Kristina

    2014-07-09

    In spite of considerable insights into the microbial diversity of marine sponges, quantitative information on microbial abundances and community composition remains scarce. Here, we established qPCR assays for the specific quantification of four bacterial phyla of representative sponge symbionts as well as the kingdoms Eubacteria and Archaea. We could show that the 16S rRNA gene numbers of Archaea, Chloroflexi, and the candidate phylum Poribacteria were 4-6 orders of magnitude higher in high microbial abundance (HMA) than in low microbial abundance (LMA) sponges and that actinobacterial 16S rRNA gene numbers were 1-2 orders higher in HMA over LMA sponges, while those for Cyanobacteria were stable between HMA and LMA sponges. Fluorescence in situ hybridization of Aplysina aerophoba tissue sections confirmed the numerical dominance of Chloroflexi, which was followed by Poribacteria. Archaeal and actinobacterial cells were detected in much lower numbers. By use of fluorescence-activated cell sorting as a primer- and probe-independent approach, the dominance of Chloroflexi, Proteobacteria, and Poribacteria in A. aerophoba was confirmed. Our study provides new quantitative insights into the microbiology of sponges and contributes to a better understanding of the HMA/LMA dichotomy. The authors quantified sponge symbionts in eight sponge species from three different locations by real time PCR targetting 16S rRNA genes. Additionally, FISH was performed and diversity and abundance of singularized microbial symbionts from Aplysina aerophoba was determined for a comprehensive quantification work. © 2014 Federation of European Microbiological Societies.

  6. Carbon translocation from symbiont to host depends on irradiance and food availability in the tropical coral Stylophora pistillata

    Science.gov (United States)

    Tremblay, P.; Grover, R.; Maguer, J. F.; Hoogenboom, M.; Ferrier-Pagès, C.

    2014-03-01

    Reef-building corals live in symbiosis with dinoflagellates that translocate a large proportion of their photosynthetically fixed carbon compounds to their coral host for its own metabolism. The carbon budget and translocation rate, however, vary depending on environmental conditions, coral host species, and symbiont clade. To quantify variability in carbon translocation in response to environmental conditions, this study assessed the effect of two different irradiance levels (120 and 250 μmol photons m-2 s-1) and feeding regimes (fed with Artemia salina nauplii and unfed) on the carbon budget of the tropical coral Stylophora pistillata. For this purpose, H13CO3 --enriched seawater was used to trace the conversion of photosynthetic carbon into symbiont and coral biomass and excrete particulate organic carbon. Results showed that carbon translocation (ca. 78 %) and utilization were similar under both irradiance levels for unfed colonies. In contrast, carbon utilization by fed colonies was dependent on the growth irradiance. Under low irradiance, heterotrophy was accompanied by lower carbon translocation (71 %), higher host and symbiont biomass, and higher calcification rates. Under high irradiance, heterotrophy was accompanied by higher rates of photosynthesis, respiration, and carbon translocation (90 %) as well as higher host biomass. Hence, levels of resource sharing within coral-dinoflagellate symbioses depend critically on environmental conditions.

  7. Toward a better understanding of the mechanisms of symbiosis: a comprehensive proteome map of a nascent insect symbiont

    Directory of Open Access Journals (Sweden)

    François Renoz

    2017-05-01

    Full Text Available Symbiotic bacteria are common in insects and can affect various aspects of their hosts’ biology. Although the effects of insect symbionts have been clarified for various insect symbiosis models, due to the difficulty of cultivating them in vitro, there is still limited knowledge available on the molecular features that drive symbiosis. Serratia symbiotica is one of the most common symbionts found in aphids. The recent findings of free-living strains that are considered as nascent partners of aphids provide the opportunity to examine the molecular mechanisms that a symbiont can deploy at the early stages of the symbiosis (i.e., symbiotic factors. In this work, a proteomic approach was used to establish a comprehensive proteome map of the free-living S. symbiotica strain CWBI-2.3T. Most of the 720 proteins identified are related to housekeeping or primary metabolism. Of these, 76 were identified as candidate proteins possibly promoting host colonization. Our results provide strong evidence that S. symbiotica CWBI-2.3T is well-armed for invading insect host tissues, and suggest that certain molecular features usually harbored by pathogenic bacteria are no longer present. This comprehensive proteome map provides a series of candidate genes for further studies to understand the molecular cross-talk between insects and symbiotic bacteria.

  8. Ancestral genetic diversity associated with the rapid spread of stress-tolerant coral symbionts in response to Holocene climate change

    KAUST Repository

    Hume, Benjamin C. C.

    2016-04-05

    Coral communities in the Persian/Arabian Gulf (PAG) withstand unusually high salinity levels and regular summer temperature maxima of up to ∼35 °C that kill conspecifics elsewhere. Due to the recent formation of the PAG and its subsequent shift to a hot climate, these corals have had only <6, 000 y to adapt to these extreme conditions and can therefore inform on how coral reefs may respond to global warming. One key to coral survival in the world\\'s warmest reefs are symbioses with a newly discovered alga, Symbiodinium thermophilum. Currently, it is unknown whether this symbiont originated elsewhere or emerged from unexpectedly fast evolution catalyzed by the extreme environment. Analyzing genetic diversity of symbiotic algae across >5, 000 km of the PAG, the Gulf of Oman, and the Red Sea coastline, we show that S. thermophilum is a member of a highly diverse, ancient group of symbionts cryptically distributed outside the PAG. We argue that the adjustment to temperature extremes by PAG corals was facilitated by the positive selection of preadapted symbionts. Our findings suggest that maintaining the largest possible pool of potentially stress-tolerant genotypes by protecting existing biodiversity is crucial to promote rapid adaptation to present-day climate change, not only for coral reefs, but for ecosystems in general.

  9. Discordant coral-symbiont structuring: factors shaping geographical variation of Symbiodinium communities in a facultative zooxanthellate coral genus, Oculina

    Science.gov (United States)

    Leydet, Karine Posbic; Hellberg, Michael E.

    2016-06-01

    Understanding the factors that help shape the association between corals and their algal symbionts, zooxanthellae ( Symbiodinium), is necessary to better understand the functional diversity and acclimatization potential of the coral host. However, most studies focus on tropical zooxanthellate corals and their obligate algal symbionts, thus limiting our full comprehension of coral-algal symbiont associations. Here, we examine algal associations in a facultative zooxanthellate coral. We survey the Symbiodinium communities associated with Oculina corals in the western North Atlantic and the Mediterranean using one clade-level marker ( psbA coding region) and three fine-scale markers ( cp23S- rDNA, b7sym15 flanking region, and b2sym17). We ask whether Oculina spp. harbor geographically different Symbiodinium communities across their geographic range and, if so, whether the host's genetics or habitat differences are correlated with this geographical variation. We found that Oculina corals harbor different Symbiodinium communities across their geographical range. Of the habitat differences (including chlorophyll a concentration and depth), sea surface temperature is better correlated with this geographical variation than the host's genetics, a pattern most evident in the Mediterranean. Our results suggest that although facultative zooxanthellate corals may be less dependent on their algal partners compared to obligate zooxanthellate corals, the Symbiodinium communities that they harbor may nevertheless reflect acclimatization to environmental variation among habitats.

  10. Low levels of mitochondrial DNA and symbiont diversity in the worldwide agricultural pest, the greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae).

    Science.gov (United States)

    Kapantaidaki, Despoina E; Ovčarenko, Irina; Fytrou, Natasa; Knott, K Emily; Bourtzis, Kostas; Tsagkarakou, Anastasia

    2015-01-01

    Trialeurodes vaporariorum, the greenhouse whitefly, is a cosmopolitan agricultural pest. Little is known about the genetic diversity of T. vaporariorum and the bacterial symbionts associated with this species. Here, we undertook a large phylogeographic study by investigating both the mitochondrial (mt) diversity and the infection status of 38 T. vaporariorum collections from 18 countries around the world. Genetic diversity of T. vaporariorum was studied by analyzing sequence data from the mt cytochrome oxidase I, cytochrome b, and NADH dehydrogenase subunit 5 genes. Maximum-likelihood (ML) phylogeny reconstruction delineated 2 clades characterized by limited sequence divergence: one clade comprised samples only from the Northern hemisphere whereas the other comprised samples from a broader geographical range. The presence of secondary symbionts was determined by PCR using primers specific for Hamiltonella, Rickettsia, Arsenophonus, Cardinium, Wolbachia, and Fritschea. Most individuals examined harbored at least one secondary endosymbiont, and Arsenophonus was detected in almost all male and female individuals. Wolbachia was present at a much lower frequency, and Cardinium was detected in only a few individuals from Greece. Rickettsia, Hamiltonella, and Fritschea were not found. Additionally, we set out to further analyze Arsenophonus diversity by multilocus sequence typing analysis; however, the Arsenophonus sequences did not exhibit any polymorphism. Our results revealed remarkably low diversity in both mtDNA and symbionts in this worldwide agricultural pest, contrasting sharply with that of the ecologically similar Bemisia tabaci.

  11. Genetics Home Reference: horizontal gaze palsy with progressive scoliosis

    Science.gov (United States)

    ... Health Conditions HGPPS horizontal gaze palsy with progressive scoliosis Printable PDF Open All Close All Enable Javascript ... collapse boxes. Description Horizontal gaze palsy with progressive scoliosis ( HGPPS ) is a disorder that affects vision and ...

  12. Effect of water depth on the performance of intelligent computing models in predicting wave transmission of floating pipe breakwater.

    Digital Repository Service at National Institute of Oceanography (India)

    Patil, S.G.; Mandal, S.; Hegde, A.V.

    Understanding the physics of complex system plays an important role in selection of data for training intelligent computing models. Based on the physics of the wave transmission of Horizontally Interlaced Multilayer Moored Floating Pipe Breakwater...

  13. Study of the Local Horizon. (Spanish Title: Estudio del Horizonte Local.) Estudo do Horizonte Local

    Science.gov (United States)

    Ros, Rosa M.

    2009-12-01

    The study of the horizon is fundamental to easy the first observations of the students at any education center. A simple model, to be developed in each center, allows to easy the study and comprehension of the rudiments of astronomy. The constructed model is presented in turn as a simple equatorial clock, other models (horizontal and vertical) may be constructed starting from it. El estudio del horizonte es fundamental para poder facilitar las primeras observaciones de los alumnos en un centro educativo. Un simple modelo, que debe realizarse para cada centro, nos permite facilitar el estudio y la comprensión de los primeros rudimentos astronómicos. El modelo construido se presenta a su vez como un sencillo modelo de reloj ecuatorial y a partir de él se pueden construir otros modelos (horizontal y vertical). O estudo do horizonte é fundamental para facilitar as primeiras observações dos alunos num centro educativo. Um modelo simples, que deve ser feito para cada centro, permite facilitar o estudo e a compreensão dos primeiros rudimentos astronômicos. O modelo construído apresenta-se, por sua vez, como um modelo simples de relógio equatorial e a partir dele pode-se construir outros modelos (horizontal e vertical)

  14. Horizontal routes: current paths of literary criticism in Latin America

    Directory of Open Access Journals (Sweden)

    Ariadne Costa da Mata

    2013-07-01

    Full Text Available In the last decades, the tendency towards horizontality became visible, particularly (but not only in social movements. Horizontality implies a new architecture in human organizations and pushes for changes in the way knowledge is produced and organized. More than a simple erosion of frontiers between fields, horizontality means the decentralization and dissemination of power.

  15. Application of Horizontal Well Technology to Liaohe Oilfield

    Institute of Scientific and Technical Information of China (English)

    HanYun

    2008-01-01

    @@ Horizontal well technology has become one of the main technologies enabling Liaohe Oilfield to realize stable development. By the end of 2006, 296 horizontal wells of various kinds had been completed in Liaohe Oil Field,273 wells had been put into production, Among uhich 237 were horizontal wells (see Table 1).

  16. YPF uses horizontal reentry to aid thin bed production

    Energy Technology Data Exchange (ETDEWEB)

    Acosta, M.R.; Leiro, F.A.; Sesano, G.S. [Yacimientos Petroliferos Fiscales, La Paz (Bolivia); Hill, D.

    1997-01-01

    Reentry and horizontal drilling/completion techniques have proven themselves useful in exploiting thin beds. A pilot horizontal reentry contracted by Yacimiento Petroliferos Fiscales (YPF) for a marginal well in its Lomita Sur field resulted in decreased water coning and production rates four times greater than expected. Further horizontal reentries in this thin-bed field are planned.

  17. The invasive Chinese pond mussel Sinanodonta woodiana (Lea, 1834 as a host for native symbionts in European waters

    Directory of Open Access Journals (Sweden)

    Anna Cichy

    2016-01-01

    Full Text Available Biological invasions are commonly observed in both the natural habitats and those which are altered by human activities. An understanding of the mechanisms involved in the successful introduction, establishment and invasion of exotic taxa is essential in predicting of changes in biodiversity and community structure. Symbiont-mediated interactions between exotic and native hosts are of special interest due to the indirect effects on population dynamics. The aim of this study was to estimate the presence of symbionts in Chinese pond mussel Sinanodonta woodiana (Lea, 1834, an exotic species of mussel in European fresh waters. The number of 340 individuals of S. woodiana was collected from Polish water bodies, including thermally heated lakes and fish ponds with natural thermal regime. The examination of mussels revealed the presence of Rhipidocotyle campanula sporocysts and cercariae (Digenea: Bucephalidae, water mites Unionicola ypsilophora (Acari: Hydracarina, oligochaetes Chaetogaster limnaei limnaei (Oligochaeta: Naididae and chironomids Glyptotendipes sp. (Diptera: Chironomidae. The global prevalence of mussels inhabited by Ch. limnaei limnaei was 7.6%, by water mites and chironomids 3.5%, and by R. campanula cercariae 2.0%. The significant difference in the number of mussels with symbionts was identified between heated lakes and fish ponds (χ2=4.15; df=1, P=0.04, with a higher global prevalence of mussels in fish ponds (22.3% compared to heated lakes (13.7%. R. campanula or U. ypsilophora were only found in mussels collected from thermally polluted lakes or fish ponds, respectively. Chironomid larvae and oligochaetes occurred in both types of water bodies. However, Glyptotendipes sp. inhabited mussels with a higher global prevalence in fish ponds than in thermally polluted lakes, while Ch. limnaei limnaei was observed mainly in hosts from heated lakes, and only from one fish pond that were not drained. Our findings indicate that the alien

  18. Diversity and Antifungal Activity of Actinomycetes Symbiont Hard Coral Mucus of Genera Goniopora and Porites

    Directory of Open Access Journals (Sweden)

    Riyanti

    2016-12-01

    Full Text Available Screening new bioactive compounds from marine actinomycete organisms associated with corals (Goniopora and Porites can be an alternative method to discover the natural antifungal compounds. This study aims to determine the density and diversity of actinomycete symbionts based on repetitive sequence-based-polymerase chain reactions (rep-PCR and to discern the ability of antifungal activity of isolates symbiotic with hard coral mucus by using a pour plate method. A total of 143 isolates were obtained from the hard coral mucus of genera Goniopora and Porites. High genetic diversity was observed among the isolates. Ten isolates with different morphological characteristics were selected to extract its secondary metabolites and then followed by an antifungal test. The isolate with the code of SCAS324 was the one with the antifungal activity, marked by the formation of a very strong inhibition zone of 54.7±0.4 mm toward Aspergillus flavus and 49.2±2.7 mm toward Candida albicans. Antifungal screening showed that the antifungal activity of the isolate SCAS324 was three times as effective as the commercial antifungal.

  19. Antimicrobial Activity of Marine Bacterial Symbionts Retrieved from Shallow Water Hydrothermal Vents.

    Science.gov (United States)

    Eythorsdottir, Arnheidur; Omarsdottir, Sesselja; Einarsson, Hjorleifur

    2016-06-01

    Marine sponges and other sessile macro-organisms were collected at a shallow water hydrothermal site in Eyjafjörður, Iceland. Bacteria were isolated from the organisms using selective media for actinomycetes, and the isolates were screened for antimicrobial activity. A total of 111 isolates revealed antimicrobial activity displaying different antimicrobial patterns which indicates production of various compounds. Known test strains were grown in the presence of ethyl acetate extracts from one selected isolate, and a clear growth inhibition of Staphylococcus aureus was observed down to 0.1 % extract concentration in the medium. Identification of isolates shows different species of Actinobacteria with Streptomyces sp. playing the largest role, but also members of Bacilli, Alphaproteobacteria and Gammaproteobacteria. Sponges have an excellent record regarding production of bioactive compounds, often involving microbial symbionts. At the hydrothermal vents, however, the majority of active isolates originated from other invertebrates such as sea anemones or algae. The results indicate that antimicrobial assays involving isolates in full growth can detect activity not visible by other methods. The macro-organisms inhabiting the Eyjafjörður hydrothermal vent area host diverse microbial species in the phylum Actinobacteria with antimicrobial activity, and the compounds responsible for the activity will be subject to further research.

  20. 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.

  1. The MicroRNA Repertoire of Symbiodinium, the Dinoflagellate Symbiont of Reef-Building Corals

    KAUST Repository

    Baumgarten, Sebastian

    2013-07-01

    Animal and plant genomes produce numerous small RNAs (smRNAs) that regulate gene expression post-transcriptionally affecting metabolism, development, and epigenetic inheritance. In order to characterize the repertoire of endogenous microRNAs and potential gene targets, we conducted smRNA and mRNA expression profiling over nine experimental treatments of cultures from the dinoflagellate Symbiodinium sp. A1, a photosynthetic symbiont of scleractinian corals. We identified a total of 75 novel smRNAs in Symbiodinum sp. A1 that share stringent key features with functional microRNAs from other model organisms. A subset of 38 smRNAs was predicted independently over all nine treatments and their putative gene targets were identified. We found 3,187 animal-like target sites in the 3’UTRs of 12,858 mRNAs and 53 plantlike target sites in 51,917 genes. Furthermore, we identified the core RNAi protein machinery in Symbiodinium. Integration of smRNA and mRNA expression profiling identified a variety of processes that could be under microRNA control, e.g. regulation of translation, DNA modification, and chromatin silencing. Given that Symbiodinium seems to have a paucity of transcription factors and differentially expressed genes, identification and characterization of its smRNA repertoire establishes the possibility of a range of gene regulatory mechanisms in dinoflagellates acting post-transcriptionally.

  2. Inherited fungal symbionts enhance establishment of an invasive annual grass across successional habitats.

    Science.gov (United States)

    Uchitel, Andrea; Omacini, Marina; Chaneton, Enrique J

    2011-02-01

    Plants infected with vertically transmitted fungal endophytes carry their microbial symbionts with them during dispersal into new areas. Yet, whether seed-borne endophytes enhance the host plant's ability to overcome colonisation barriers and to regenerate within invaded sites remains poorly understood. We examined how symbiosis with asexual endophytic fungi (Neotyphodium) affected establishment and seed loss to predators in the invasive annual grass Lolium multiflorum (Italian ryegrass) across contrasting successional plots. Italian ryegrass seeds with high and low endophyte incidence were sown into three communities: a 1-year-old fallow field, a 15-year-old grassland, and a 24-year-old forest, which conformed to an old-field chronosequence in the eastern Inland Pampa, Argentina. We found that endophyte infection consistently increased host population recruitment and reproductive output. Endophyte presence also enhanced aerial biomass production of ryegrass in a low recruitment year but not in a high recruitment year, suggesting that symbiotic effects on growth performance are density dependent. Endophyte presence reduced seed removal by rodents, although differential predation may not account for the increased success of infected grass populations. Overall, there was no statistical evidence for an endophyte-by-site interaction, indicating that the fungal endosymbiont benefitted host establishment regardless of large differences in biotic and abiotic environment among communities. Our results imply that hereditary endophytes may increase the chances for host grass species to pass various ecological filters associated with invasion resistance across a broad range of successional habitats.

  3. Cytonuclear Epistasis Controls the Density of Symbiont Wolbachia pipientis in Nongonadal Tissues of Mosquito Culex quinquefasciatus.

    Science.gov (United States)

    Emerson, Kevin J; Glaser, Robert L

    2017-08-07

    Wolbachia pipientis, a bacterial symbiont infecting arthropods and nematodes, is vertically transmitted through the female germline and manipulates its host's reproduction to favor infected females. Wolbachia also infects somatic tissues where it can cause nonreproductive phenotypes in its host, including resistance to viral pathogens. Wolbachia-mediated phenotypes are strongly associated with the density of Wolbachia in host tissues. Little is known, however, about how Wolbachia density is regulated in native or heterologous hosts. Here, we measure the broad-sense heritability of Wolbachia density among families in field populations of the mosquito Culex pipiens, and show that densities in ovary and nongonadal tissues of females in the same family are not correlated, suggesting that Wolbachia density is determined by distinct mechanisms in the two tissues. Using introgression analysis between two different strains of the closely related species C. quinquefasciatus, we show that Wolbachia densities in ovary tissues are determined primarily by cytoplasmic genotype, while densities in nongonadal tissues are determined by both cytoplasmic and nuclear genotypes and their epistatic interactions. Quantitative-trait-locus mapping identified two major-effect quantitative-trait loci in the C. quinquefasciatus genome explaining a combined 23% of variance in Wolbachia density, specifically in nongonadal tissues. A better understanding of how Wolbachia density is regulated will provide insights into how Wolbachia density can vary spatiotemporally in insect populations, leading to changes in Wolbachia-mediated phenotypes such as viral pathogen resistance. Copyright © 2017 Emerson, Glaser.

  4. Effects of large mammalian herbivores and ant symbionts on condensed tannins of Acacia drepanolobium in Kenya.

    Science.gov (United States)

    Ward, David; Young, Truman P

    2002-05-01

    Condensed tannins have been considered to be important inducible defenses against mammalian herbivory. We tested for differences in condensed tannin defenses in Acacia drepanolobium in Kenya over two years among different large mammalian herbivore treatments [total exclusion, antelope only, and megaherbivore (elephants and giraffes) + antelope] and with four different ant symbiont species on the trees. We predicted that (1) condensed tannin concentrations would be lowest in the mammal treatment with the lowest level of herbivory (total exclusion), (2) trees occupied by mutualist ants that protect the trees most aggressively would have lower levels of tannins, and (3) if chemical defense production is costly, there would be a trade-off between tannin concentrations, growth, and mechanical defenses. Mean tannin concentrations increased from total exclusion treatments to wildlife-only treatments to megaherbivore + antelope treatments. In 1997, condensed tannin concentrations were significantly lower in trees occupied by the ant Crematogaster nigriceps, the only ant species that actively removed axillary buds. Contrary to our prediction, trees occupied by ant species that protect the trees more aggressively against mammalian herbivores did not have lower overall levels of condensed tannins. There was no consistent evidence of a trade-off between tannin concentrations and growth rate, but there was a positive correlation between mean thorn length and mean tannin concentrations across species of ant inhabitants and across herbivore treatments in 1997. Contrary to our expectation, trees had higher tannin concentrations in the upper parts of the canopy where there is little herbivory by mammals.

  5. Phylogenetic relationship of Lotus uliginosus symbionts with bradyrhizobia nodulating genistoid legumes.

    Science.gov (United States)

    Lorite, María J; Videira e Castro, Isabel; Muñoz, Socorro; Sanjuán, Juan

    2012-02-01

    Lotus species are legumes with potential for pastures in soils with low-fertility and environmental constraints. The aim of this work was to characterize bacteria that establish efficient nitrogen-fixing symbiosis with the forage species Lotus uliginosus. A total of 39 isolates were obtained from nodules of L. uliginosus naturally growing in two different locations of Portugal. Molecular identification of the isolates plus the commercial inoculant strain NZP2039 was performed by REP-PCR, 16S rRNA RFLP, and 16S rRNA, glnII and recA sequence analyses. Limited genetic diversity was found among the L. uliginosus symbionts, which showed a close phylogenetic relationship with the species Bradyrhizobium japonicum. The symbiotic nifH, nodA and nodC gene sequences were closely related with the corresponding genes of various Bradyrhizobium strains isolated from Lupinus and other genistoid legumes and therefore were phylogenetically separated from other Lotus spp. rhizobia. The L. uliginosus bradyrhizobia were able to nodulate and fix nitrogen in association with L. uliginosus, could nodulate Lotus corniculatus with generally poor nitrogen-fixing efficiency, formed nonfixing nodules in Lotus tenuis and Lupinus luteus roots and were unable to nodulate Glycine soja or Glycine max. Thus, L. uliginosus rhizobia seem closely related to B. japonicum biovar genistearum strains.

  6. Shared Ancestry of Symbionts? Sagrinae and Donaciinae (Coleoptera, Chrysomelidae Harbor Similar Bacteria

    Directory of Open Access Journals (Sweden)

    Dimitra Synefiaridou

    2012-05-01

    Full Text Available When symbioses between insects and bacteria are discussed, the origin of a given association is regularly of interest. We examined the evolution of the symbiosis between reed beetles (Coleoptera, Chrysomelidae, Donaciinae and intracellular symbionts belonging to the Enterobacteriaceae. We analyzed the partial sequence of the 16S rRNA to assess the phylogenetic relationships with bacteria we found in other beetle groups (Cerambycidae, Anobiidae, other Chrysomelidae. We discuss the ecology of each association in the context of the phylogenetic analysis. The bacteria in Sagra femorata (Chrysomelidae, Sagrinae are very closely related to those in the Donaciinae and are located in similar mycetomes. The Sagrinae build a cocoon for pupation like the Donaciinae, in which the bacteria produce the material required for the cocoon. These aspects support the close relationship between Sagrinae and Donaciinae derived in earlier studies and make a common ancestry of the symbioses likely. Using PCR primers specific for fungi, we found Candida sp. in the mycetomes of a cerambycid beetle along with the bacteria.

  7. A polyketide synthase-peptide synthetase gene cluster from an uncultured bacterial symbiont of Paederus beetles.

    Science.gov (United States)

    Piel, Jörn

    2002-10-29

    Many drug candidates from marine and terrestrial invertebrates are suspected metabolites of uncultured bacterial symbionts. The antitumor polyketides of the pederin family, isolated from beetles and sponges, are an example. Drug development from such sources is commonly hampered by low yields and the difficulty of sustaining invertebrate cultures. To obtain insight into the true producer and find alternative supplies of these rare drug candidates, the putative pederin biosynthesis genes were cloned from total DNA of Paederus fuscipes beetles, which use this compound for chemical defense. Sequence analysis of the gene cluster and adjacent regions revealed the presence of ORFs with typical bacterial architecture and homologies. The ped cluster, which is present only in beetle specimens with high pederin content, is located on a 54-kb region bordered by transposase pseudogenes and encodes a mixed modular polyketide synthase/nonribosomal peptide synthetase. Notably, none of the modules contains regions with homology to acyltransferase domains, but two copies of isolated monodomain acyltransferase genes were found at the upstream end of the cluster. In line with an involvement in pederin biosynthesis, the upstream cluster region perfectly mirrors pederin structure. The unexpected presence of additional polyketide synthase/nonribosomal peptide synthetase modules reveals surprising insights into the evolutionary relationship between pederin-type pathways in beetles and sponges.

  8. The response to nitric oxide of the nitrogen-fixing symbiont Sinorhizobium meliloti.

    Science.gov (United States)

    Meilhoc, Eliane; Cam, Yvan; Skapski, Agnès; Bruand, Claude

    2010-06-01

    Nitric oxide (NO) is crucial in animal- and plant-pathogen interactions, during which it participates in host defense response and resistance. Indications for the presence of NO during the symbiotic interaction between the model legume Medicago truncatula and its symbiont Sinorhizobium meliloti have been reported but the role of NO in symbiosis is far from being elucidated. Our objective was to understand the role or roles played by NO in symbiosis. As a first step toward this goal, we analyzed the bacterial response to NO in culture, using a transcriptomic approach. We identified approximately 100 bacterial genes whose expression is upregulated in the presence of NO. Surprisingly, most of these genes are regulated by the two-component system FixLJ, known to control the majority of rhizobial genes expressed in planta in mature nodules, or the NO-dedicated regulator NnrR. Among the genes responding to NO is hmp, encoding a putative flavohemoglobin. We report that an hmp mutant displays a higher sensitivity toward NO in culture and leads to a reduced nitrogen fixation efficiency in planta. Because flavohemoglobins are known to detoxify NO in numerous bacterial species, this result is the first indication of the importance of the bacterial NO response in symbiosis.

  9. Eco-taxonomic insights into actinomycete symbionts of termites for discovery of novel bioactive compounds.

    Science.gov (United States)

    Kurtböke, D Ipek; French, John R J; Hayes, R Andrew; Quinn, Ronald J

    2015-01-01

    Termites play a major role in foraging and degradation of plant biomass as well as cultivating bioactive microorganisms for their defense. Current advances in "omics" sciences are revealing insights into function-related presence of these symbionts, and their related biosynthetic activities and genes identified in gut symbiotic bacteria might offer a significant potential for biotechnology and biodiscovery. Actinomycetes have been the major producers of bioactive compounds with an extraordinary range of biological activities. These metabolites have been in use as anticancer agents, immune suppressants, and most notably, as antibiotics. Insect-associated actinomycetes have also been reported to produce a range of antibiotics such as dentigerumycin and mycangimycin. Advances in genomics targeting a single species of the unculturable microbial members are currently aiding an improved understanding of the symbiotic interrelationships among the gut microorganisms as well as revealing the taxonomical identity and functions of the complex multilayered symbiotic actinofloral layers. If combined with target-directed approaches, these molecular advances can provide guidance towards the design of highly selective culturing methods to generate further information related to the physiology and growth requirements of these bioactive actinomycetes associated with the termite guts. This chapter provides an overview on the termite gut symbiotic actinoflora in the light of current advances in the "omics" science, with examples of their detection and selective isolation from the guts of the Sunshine Coast regional termite Coptotermes lacteus in Queensland, Australia.

  10. Molecular details of a starch utilization pathway in the human gut symbiont Eubacterium rectale.

    Science.gov (United States)

    Cockburn, Darrell W; Orlovsky, Nicole I; Foley, Matthew H; Kwiatkowski, Kurt J; Bahr, Constance M; Maynard, Mallory; Demeler, Borries; Koropatkin, Nicole M

    2015-01-01

    Eubacterium rectale is a prominent human gut symbiont yet little is known about the molecular strategies this bacterium has developed to acquire nutrients within the competitive gut ecosystem. Starch is one of the most abundant glycans in the human diet, and E. rectale increases in vivo when the host consumes a diet rich in resistant starch, although it is not a primary degrader of this glycan. Here we present the results of a quantitative proteomics study in which we identify two glycoside hydrolase 13 family enzymes, and three ABC transporter solute-binding proteins that are abundant during growth on starch and, we hypothesize, work together at the cell surface to degrade starch and capture the released maltooligosaccharides. EUR_21100 is a multidomain cell wall anchored amylase that preferentially targets starch polysaccharides, liberating maltotetraose, whereas the membrane-associated maltogenic amylase EUR_01860 breaks down maltooligosaccharides longer than maltotriose. The three solute-binding proteins display a range of glycan-binding specificities that ensure the capture of glucose through maltoheptaose and some α1,6-branched glycans. Taken together, we describe a pathway for starch utilization by E. rectale DSM 17629 that may be conserved among other starch-degrading Clostridium cluster XIVa organisms in the human gut.

  11. Prebiotic galactooligosaccharides activate mucin and pectic galactan utilization pathways in the human gut symbiont Bacteroides thetaiotaomicron

    Science.gov (United States)

    Lammerts van Bueren, Alicia; Mulder, Marieke; Leeuwen, Sander van; Dijkhuizen, Lubbert

    2017-01-01

    Galactooligosaccharides (GOS) are prebiotic carbohydrates that impart changes in the gut bacterial composition of formula-fed infants to more closely resemble that of breast-fed infants. Consuming human milk oligosaccharides (HMOs) provides specific bacterial strains with an advantage for colonizing the infant intestine. These same effects are seen in infants after GOS consumption, however GOS are very complex mixtures and the underlying molecular mechanisms of how GOS mimic HMOs are relatively unknown. Here we studied the effects of GOS utilization on a prominent gut symbiont, Bacteroides thetaiotaomicron, which has been previously shown to consume HMOs via mucin O-glycan degradation pathways. We show that several pathways for targeting O-mucin glycans are activated in B. thetaiotaomicron by GOS, as well as the galactan utilization sytem. Characterization of the endo-galactanase from this system identified activity on various longer GOS substrates while a subset of GOS compounds were identified as potential activators of mucin glycan metabolism in B. thetaiotaomicron. Our results show that GOS functions as an inducer of mucin-glycan pathways while providing a nutrient source in the form of β-(1 → 4)-galactan. These metabolic features of GOS mixtures may serve to explain the beneficial effects that are seen for GOS supplemented infant formula. PMID:28091546

  12. Bacterial Endo-Symbiont Inhabiting Tridax procumbens L. and Their Antimicrobial Potential

    <