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Sample records for symbiont bearing foraminifera

  1. 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

    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......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...

  2. Molecular evidence for Lessepsian invasion of soritids (larger symbiont bearing benthic foraminifera.

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    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.

  3. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera.

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    Joost W van Dam

    Full Text Available Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m, while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v/F(m, interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v/F(m and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1. The mixture toxicity model of Independent Action (IA described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures.

  4. Additive pressures of elevated sea surface temperatures and herbicides on symbiont-bearing foraminifera.

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    van Dam, Joost W; Negri, Andrew P; Mueller, Jochen F; Altenburger, Rolf; Uthicke, Sven

    2012-01-01

    Elevated ocean temperatures and agrochemical pollution individually threaten inshore coral reefs, but these pressures are likely to occur simultaneously. Experiments were conducted to evaluate the combined effects of elevated temperature and the photosystem II (PSII) inhibiting herbicide diuron on several types of symbiotic algae (diatom, dinoflagellate or rhodophyte) of benthic foraminifera in hospite. Diuron was shown to evoke a direct effect on photosynthetic efficiency (reduced effective PSII quantum yield ΔF/F'(m)), while elevated temperatures (>30 °C, only 2 °C above current average summer temperatures) were observed to impact photosynthesis more indirectly by causing reductions in maximum PSII quantum yield (F(v)/F(m)), interpreted as photodamage. Additionally, elevated temperatures were shown to cause bleaching through loss of chlorophyll a in foraminifera hosting either diatoms or dinoflagellates. A significant linear correlation was found between reduced F(v)/F(m) and loss of chlorophyll a. In most cases, symbionts within foraminifera proved more sensitive to thermal stress in the presence of diuron (≥ 1 µg L(-1)). The mixture toxicity model of Independent Action (IA) described the combined effects of temperature and diuron on the photosystem of species hosting diatoms or dinoflagellates convincingly and in agreement with probabilistic statistics, so a response additive joint action can be assumed. We thus demonstrate that improving water quality can improve resilience of symbiotic phototrophs to projected increases in ocean temperatures. As IA described the observed combined effects from elevated temperature and diuron stress it may therefore be employed for prediction of untested mixtures and for assessing the efficacy of management measures.

  5. Recent Invasion of the Symbiont-Bearing Foraminifera Pararotalia into the Eastern Mediterranean Facilitated by the Ongoing Warming Trend.

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    Christiane Schmidt

    Full Text Available The eastern Mediterranean is a hotspot of biological invasions. Numerous species of Indo-pacific origin have colonized the Mediterranean in recent times, including tropical symbiont-bearing foraminifera. Among these is the species Pararotalia calcariformata. Unlike other invasive foraminifera, this species was discovered only two decades ago and is restricted to the eastern Mediterranean coast. Combining ecological, genetic and physiological observations, we attempt to explain the recent invasion of this species in the Mediterranean Sea. Using morphological and genetic data, we confirm the species attribution to P. calcariformata McCulloch 1977 and identify its symbionts as a consortium of diatom species dominated by Minutocellus polymorphus. We document photosynthetic activity of its endosymbionts using Pulse Amplitude Modulated Fluorometry and test the effects of elevated temperatures on growth rates of asexual offspring. The culturing of asexual offspring for 120 days shows a 30-day period of rapid growth followed by a period of slower growth. A subsequent 48-day temperature sensitivity experiment indicates a similar developmental pathway and high growth rate at 28°C, whereas an almost complete inhibition of growth was observed at 20°C and 35°C. This indicates that the offspring of this species may have lower tolerance to cold temperatures than what would be expected for species native to the Mediterranean. We expand this hypothesis by applying a Species Distribution Model (SDM based on modern occurrences in the Mediterranean using three environmental variables: irradiance, turbidity and yearly minimum temperature. The model reproduces the observed restricted distribution and indicates that the range of the species will drastically expand westwards under future global change scenarios. We conclude that P. calcariformata established a population in the Levant because of the recent warming in the region. In line with observations from other

  6. 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....... No photoinhibition was observed up to an irradiance of 2000 pmol photons m-2 s-1. Net photosynthesis (at saturating irradiance) and dark respiration rates were 3.7-22.7 and 5.6-14.3 nmol O2 foraminifer-1 h-1, respectively. Simultaneous CO2, pH and O2 measurements at the shell surface of A. hemprichii during...... experimental light-dark cycles showed rapid concentration changes of all three variables upon light-dark or dark-light shifts. The dynamics of O2 and CO2 at the shell surface of A. hemprichii showed unequal net conversion rates of O2 and CO2 during experimental light-dark cycles. The molar O2/CO2 conversion...

  7. Combined effects of sea water acidification and copper exposure on the symbiont-bearing foraminifer Amphistegina gibbosa

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    Marques, Joseane Aparecida; de Barros Marangoni, Laura Fernandes; Bianchini, Adalto

    2017-06-01

    Coral reefs are threatened by global and local stressors such as ocean acidification and trace metal contamination. Reliable early warning monitoring tools are needed to assess and monitor coral reef health. Symbiont-bearing foraminifers ( Amphistegina gibbosa) were kept under ambient conditions (no sea water acidification and no copper addition) or exposed to combinations of different levels of sea water pH (8.1, 7.8, 7.5 and 7.2) and environmentally relevant concentrations of dissolved copper (measured: 1.0, 1.6, 2.3 and 3.2 µg L-1) in a mesocosm system. After 10- and 25-d exposure, foraminifers were analyzed for holobiont Ca2+-ATPase activity, bleaching, growth and mortality. Enzyme activity was inhibited in foraminifers exposed to pH 7.2 and 3.2 µg L-1 Cu for 25 d. Bleaching frequency was also higher at pH 7.2 combined with copper addition. There was no significant effect of sea water acidification and copper addition on mortality. However, test size was smaller in foraminifers exposed to copper, with a positive interactive effect of sea water acidification. These findings can be explained by the higher availability of free copper ions at lower water pH. This condition would increase Cu competition with Ca2+ for the binding sites on the organism, thus inhibiting Ca2+-ATPase activity and affecting the organism's overall fitness. Findings reported here suggest that key processes in A. gibbosa, such as calcification and photosynthesis, are affected by the combined effect of global (sea water acidification) and local (copper contamination) stressors. Considering the experimental conditions employed (mesocosm system, possible ocean acidification scenarios, low copper concentrations, biomarkers of ecological relevance and chronic exposure), our findings support the use of foraminifera and biomarkers analyzed in the present study as reliable tools to detect and monitor the ecological impacts of multiple stressors in coral reef environments.

  8. Oxygen isotope fractionation and algal symbiosis in benthic foraminifera from the Gulf of Elat, Israel

    International Nuclear Information System (INIS)

    Buchardt, B.; Hansen, H.J.

    1977-01-01

    In order to investigate possible isotopic fractionations due to algal symbiosis the oxygen and carbon isotope compositions of shell carbonate from symbiont-free and symbiont-bearing benthic foraminifera have been compared to that of molluscs living at the same locality. The material was collected over a depth profile in the Gulf of Elat (Aqaba), Israel, covering the interval from 4 to 125 metres. After corrections variations for temperature with depth, characteristic 18 O-depletions were observed in the foraminiferal shell carbonate when compared to the molluscs. These depletions are interpreted as 1) a constant vital effect seen in all the foraminifera studied and 2) an additional, light-dependent vital effect observed in the symbiont-bearing forms only, caused by incorporation of photosynthetic oxygen formed by the symbiotic algae. This additional vital effect emphasizes the difficulties in applying foraminifera to oxygen isotope palaeotemperature analyses. No well-defined differences in carbon isotope compositions are observed between symbiont-bearing and symbiont-free foraminifera. (author)

  9. Larger foraminifera distribution on a mesotrophic carbonate shelf in SW Sulawesi (Indonesia)

    NARCIS (Netherlands)

    Renema, W.; Troelstra, S.R.

    2001-01-01

    Larger symbiont bearing foraminifera typically live in shallow tropical seas. In this study the fauna composition of patch reefs scattered over the Spermonde Shelf (SW Sulawesi, Indonesia), a mesotrophic carbonate shelf, is examined. The foraminiferal fauna of the Spermonde Shelf is characterised by

  10. Intra-shell boron isotope ratios in the symbiont-bearing benthic foraminiferan Amphistegina lobifera: Implications for δ 11B vital effects and paleo-pH reconstructions

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    Rollion-Bard, C.; Erez, J.

    2010-03-01

    The boron isotope composition of marine carbonates is considered to be a seawater pH proxy. Nevertheless, the use of δ 11B has some limitations such as the knowledge of the fractionation factor ( α4-3) between boric acid and the borate ion and the amplitude of "vital effects" on this proxy that are not well constrained. Using secondary ion mass spectrometry (SIMS) we have examined the internal variability of the boron isotope ratio in the shallow water, symbionts bearing foraminiferan Amphistegina lobifera. Specimens were cultured at constant temperature (24 ± 0.1 °C) in seawater with pH ranging between 7.90 and 8.45. Intra-shell boron isotopes showed large variability with an upper limit value of ≈30‰. Our results suggest that the fractionation factor α4-3 of 0.97352 ( Klochko et al., 2006) is in better agreement with our experiments and with direct pH measurements in seawater vacuoles associated with the biomineralization process in these foraminifera. Despite the large variability of the skeletal pH values in each cultured specimen, it is possible to link the lowest calculated pH values to the experimental culture pH values while the upper pH limit is slightly below 9. This variability can be interpreted as follows: foraminifera variably increase the pH at the biomineralization site to about 9. This increase above ambient seawater pH leads to a range in δ 11B (Δ 11B) for each seawater pH. This Δ 11B is linearly correlated with the culture seawater pH with a slope of -13.1 per pH unit, and is independent of the fractionation factor α4-3, or the δ 11B sw through time. It may also be independent of the p KB (the dissociation constant of boric acid) value. Therefore, Δ 11B in foraminifera can potentially reconstruct paleo-pH of seawater.

  11. Ticks and tick-borne pathogens and putative symbionts of black bears (Ursus americanus floridanus) from Georgia and Florida.

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    Yabsley, Michael J; Nims, Todd N; Savage, Mason Y; Durden, Lance A

    2009-10-01

    Ticks were collected from 38 black bears (Ursus americanus floridanus) from northwestern Florida (n = 18) from 2003 to 2005 and southern Georgia (n = 20) in 2006. Five species (Amblyomma americanum, A. maculatum, Dermacentor variabilis, Ixodes scapularis, and I. affinis) were collected from Florida bears, and 4 species (A. americanum, A. maculatum, D. variabilis, I. scapularis) were collected from bears in Georgia. Ixodes scapularis was the most frequently collected tick, followed by D. variabilis, A. americanum, A. maculatum, and I. affinis. The collection of I. affinis from a Florida bear represents a new host record. A subset of ticks was screened for pathogens and putative symbionts by polymerase chain reaction (PCR). The zoonotic tick-borne pathogens Ehrlichia chaffeensis and Rickettsia parkeri were detected in 1 of 23 (4.3%) A. americanum and 1 of 12 (8.3%) A. maculatum, respectively. The putative zoonotic pathogen "Rickettsia amblyommii" was detected in 4 (17.4%) A. americanum and 1 (8.3%) A. maculatum. Other putative symbiotic rickettsiae detected included R. bellii and R. montanensis in D. variabilis, a Rickettsia cooleyi-like sp. and Rickettsia sp. Is-1 in I. scapularis, and Rickettsia TR39-like sp. in I. scapularis and A. americanum. All ticks were PCR-negative for Anaplasma phagocytophilum, Panola Mountain Ehrlichia sp., E. ewingii, Francisella tularensis, and Borrelia spp.

  12. Spatial distribution of symbiont-bearing dinoflagellates in the Indian Ocean in relation to oceanographic regimes

    DEFF Research Database (Denmark)

    Tarangkoon, Woraporn; Hansen, Gert; Hansen, Per Juel

    2010-01-01

    . Under light microscopy, some of the food vacuoles of Ornithocercus spp. resembled ectosymbionts in size, shape and colour. Transmission electron microscopy of O. magnificus and O. quadratus revealed the presence of a peduncle and many rhabdosomes; both may serve in prey capture. Also, numerous food...... vacuoles were present, but their content was generally too degraded for a proper identification of prey type. However, occasionally remnants of eukaryotes were observed, indicating that Ornithocercus spp. may feed on ciliates. Thus, our data suggest that the ectosymbiont-bearing dinoflagellates use a multi...

  13. Extremely heat tolerant photo-symbiosis in a shallow marine benthic foraminifera

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    Schmidt, C.; Titelboim, D.; Brandt, J.; Herut, B.; Abramovich, S.; Almogi-Labin, A.; Kucera, M.

    2016-08-01

    Bleaching, the loss of algal symbionts, occurs in marine photosymbiotic organisms at water temperatures minimally exceeding average summer SST (sea surface temperatures). Pre-adaptation allows organisms to persist under warmer conditions, providing the tolerance can be carried to new habitats. Here we provide evidence for the existence of such adaptation in the benthic foraminifera Pararotalia calcariformata. This species occurs at a thermally polluted site in the Mediterranean, where water temperatures reach a maxima daily average of 36 °C during the summer. To test whether this occurrence represents a widespread adaptation, we conducted manipulative experiments exposing this species from an unpolluted site to elevated temperatures (20-42 °C). It was kept in co-culture with the more thermally sensitive foraminifera Amphistegina lobifera in two experiments (20-36 °C). Reduced photosynthetic activity in A. lobifera occurred at 32 °C whereas photochemical stress in P. calcariformata was first observed during exposure to 36 °C. Pararotalia calcariformata survived all treatment conditions and grew under 36 °C. The photosymbiosis in P. calcariformata is unusually thermally tolerant. These observations imply that marine eukaryote-eukaryote photosymbiosis can respond to elevated temperatures by drawing on a pool of naturally occurring pre-adaptations. It also provides a perspective on the massive occurrence of symbiont-bearing foraminifera in the early Cenozoic hothouse climate.

  14. Benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Nigam, R.

    sensitive to the changes in ambient environment. The response of benthic foraminifera to the changes in the ambient environment is incorporated in their tests, which have high preservation potential. Therefore, the characteristics of the benthic...

  15. Distribution of foraminifera in the Cochin estuary

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Balasubramanian, T.

    monsoon seasons for prevalence of marine conditions. Further, it has been noted that texture of the sediments has a bearing on the faunal density. Also, an environmental assessment study of the deepening of the navigation channel on Foraminifera...

  16. Size-related stable isotope changes in planktic foraminifera across the "Latest Danian Event" (ODP Site 1262, Walvis Ridge)

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    Lägel, Friederike; Jehle, Sofie; Deprez, Arne; Speijer, Robert; Bornemann, André

    2015-04-01

    The Latest Danian Event (LDE, ~62.15 Ma) represents a transient carbon cycle perturbation on a global scale similar to the Paleocene-Eocene Thermal Maximum, but of a much lower magnitude. This event took place during a time interval that is characterized by major changes in the calcareous plankton communities like the appearance and diversification of the fasciculithid nannolith group and the establishment of dinoflagellate photosymbiosis within the Praemurica/Morozovella planktic foraminifera. Size-related isotope changes (d13C, d18O) of planktic foraminifera might indicate changes in the depth habitat of foraminifera with ontogeny. An increase in d13C with size may point to the existence of (dinoflagellate) photosymbionts, and are often used to identify photosymbiosis in extinct foraminifera. Size fraction data on middle Paleocene taxa are generally rare and only poorly constrained concerning their stratigraphic age. Here we present detailed isotopic data from seven samples across the LDE of seven taxa including the asymbiotic Parasubbotina variospira and various symbiont-bearing taxa of the Praemurica, Morozovella and Igorina lineages that provide new insights into the life style of these taxa. Moreover, we intend to test if photosymbiotic activity changes occur during the LDE.

  17. Paleozoic Foraminifera.

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    Ross, C A; Ross, J R

    1991-01-01

    The approximately 300 million years that make up Paleozoic time saw the evolution of eight of the fifteen recognized suborders of Foraminifera. Of the suborders present in the Paleozoic, seven are morphologically relatively simple, slowly evolving, and continued into Mesozoic and Cenozoic times to become the ancestoral lineages from which evolved several additional post-Paleozoic suborders. In contrast, an eighth Paleozoic suborder, the Fusulinina, was an abundant, ecologically dominant group that evolved from simple to highly specialized forms and had a history of rapid evolution with diverse lineages. Fusulinines became extinct at the end of the Paleozoic. Their early representatives may have given rise to three and eventually four post-Paleozoic suborders. A number of suborders in the Paleozoic have similar, supposedly independent, early evolutionary patterns with the following series of morphological steps: (1) single chambers with or without apertures depending on the amount of wall cement; (2) groups of chambers that appear to be buds or aggregations of individuals rather than true chambers; (3) a proloculus followed by a tubular second chamber that is first erect and gradually evolves into enrolled free-living individuals; (4) development of constrictions in the tubular chamber; and finally (5) evolution of true chambers. These morphological steps, which are basic organizational steps with evolutionary significance, appear in lineages with quite different test compositions and, therefore, are considered only distantly related in the present classification.

  18. Selective responses of benthic foraminifera to thermal pollution.

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    Titelboim, Danna; Almogi-Labin, Ahuva; Herut, Barak; Kucera, Michal; Schmidt, Christiane; Hyams-Kaphzan, Orit; Ovadia, Ofer; Abramovich, Sigal

    2016-04-15

    Persistent thermohaline pollution at a site along the northern coast of Israel, due to power and desalination plants, is used as a natural laboratory to evaluate the effects of rising temperature and salinity levels on benthic foraminifera living in shallow hard-bottom habitats. Biomonitoring of the disturbed area and a control station shows that elevated temperature is a more significant stressor compared to salinity, thus causing a decrease in abundance and richness. Critical temperature thresholds were observed at 30 and 35°C, the latter representing the most thermally tolerant species in the studied area Pararotalia calcariformata, which is the only symbiont-bearing species observed within the core of the heated area. Common species of the shallow hard-bottom habitats including several Lessepsian invaders are almost absent in the most exposed site indicating that excess warming will likely impede the survival of these species that currently benefit from the ongoing warming of the Eastern Mediterranean. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. How to react to shallow water hydrodynamics: The larger benthic foraminifera solution.

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    Briguglio, Antonino; Hohenegger, Johann

    2011-11-01

    Symbiont-bearing larger benthic foraminifera inhabit the photic zone to provide their endosymbiotic algae with light. Because of the hydrodynamic conditions of shallow water environments, tests of larger foraminifera can be entrained and transported by water motion. To resist water motion, these foraminifera have to build a test able to avoid transport or have to develop special mechanisms to attach themselves to substrate or to hide their test below sediment grains. For those species which resist transport by the construction of hydrodynamic convenient shapes, the calculation of hydrodynamic parameters of their test defines the energetic input they can resist and therefore the scenario where they can live in. Measuring the density, size and shape of every test, combined with experimental data, helps to define the best mathematical approach for the settling velocity and Reynolds number of every shell. The comparison between water motion at the sediment-water interface and the specimen-specific settling velocity helps to calculate the water depths at which, for a certain test type, transport, deposition and accumulation may occur. The results obtained for the investigated taxa show that the mathematical approach gives reliable results and can discriminate the hydrodynamic behaviour of different shapes. Furthermore, the study of the settling velocities, calculated for all the investigated taxa, shows that several species are capable to resist water motion and therefore they appear to be functionally adapted to the hydrodynamic condition of its specific environment. The same study is not recommended on species which resist water motion by adopting hiding or anchoring strategies to avoid the effect of water motion.

  20. Spatial Patterns in the Distribution, Diversity and Abundance of Benthic Foraminifera around Moorea (Society Archipelago, French Polynesia).

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    Fajemila, Olugbenga T; Langer, Martin R; Lipps, Jere H

    2015-01-01

    Coral reefs are now subject to global threats and influences from numerous anthropogenic sources. Foraminifera, a group of unicellular shelled organisms, are excellent indicators of water quality and reef health. Thus we studied a set of samples taken in 1992 to provide a foraminiferal baseline for future studies of environmental change. Our study provides the first island-wide analysis of shallow benthic foraminifera from around Moorea (Society Archipelago). We analyzed the composition, species richness, patterns of distribution and abundance of unstained foraminiferal assemblages from bays, fringing reefs, nearshore and back- and fore-reef environments. A total of 380 taxa of foraminifera were recorded, a number that almost doubles previous species counts. Spatial patterns of foraminiferal assemblages are characterized by numerical abundances of individual taxa, cluster groups and gradients of species richness, as documented by cluster, Fisher α, ternary plot and Principal Component Analyses (PCA). The inner bay inlets are dominated by stress-tolerant, mostly thin-shelled taxa of Bolivina, Bolivinella, Nonionoides, Elongobula, and Ammonia preferring low-oxygen and/or nutrient-rich habitats influenced by coastal factors such as fresh-water runoff and overhanging mangroves. The larger symbiont-bearing foraminifera (Borelis, Amphistegina, Heterostegina, Peneroplis) generally live in the oligotrophic, well-lit back- and fore-reef environments. Amphisteginids and peneroplids were among the few taxa found in the bay environments, probably due to their preferences for phytal substrates and tolerance to moderate levels of eutrophication. The fringing reef environments along the outer bay are characterized by Borelis schlumbergeri, Heterostegina depressa, Textularia spp. and various miliolids which represent a hotspot of diversity within the complex reef-lagoon system of Moorea. The high foraminiferal Fisher α and species richness diversity in outer bay fringing reefs

  1. Spatial Patterns in the Distribution, Diversity and Abundance of Benthic Foraminifera around Moorea (Society Archipelago, French Polynesia.

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    Olugbenga T Fajemila

    Full Text Available Coral reefs are now subject to global threats and influences from numerous anthropogenic sources. Foraminifera, a group of unicellular shelled organisms, are excellent indicators of water quality and reef health. Thus we studied a set of samples taken in 1992 to provide a foraminiferal baseline for future studies of environmental change. Our study provides the first island-wide analysis of shallow benthic foraminifera from around Moorea (Society Archipelago. We analyzed the composition, species richness, patterns of distribution and abundance of unstained foraminiferal assemblages from bays, fringing reefs, nearshore and back- and fore-reef environments. A total of 380 taxa of foraminifera were recorded, a number that almost doubles previous species counts. Spatial patterns of foraminiferal assemblages are characterized by numerical abundances of individual taxa, cluster groups and gradients of species richness, as documented by cluster, Fisher α, ternary plot and Principal Component Analyses (PCA. The inner bay inlets are dominated by stress-tolerant, mostly thin-shelled taxa of Bolivina, Bolivinella, Nonionoides, Elongobula, and Ammonia preferring low-oxygen and/or nutrient-rich habitats influenced by coastal factors such as fresh-water runoff and overhanging mangroves. The larger symbiont-bearing foraminifera (Borelis, Amphistegina, Heterostegina, Peneroplis generally live in the oligotrophic, well-lit back- and fore-reef environments. Amphisteginids and peneroplids were among the few taxa found in the bay environments, probably due to their preferences for phytal substrates and tolerance to moderate levels of eutrophication. The fringing reef environments along the outer bay are characterized by Borelis schlumbergeri, Heterostegina depressa, Textularia spp. and various miliolids which represent a hotspot of diversity within the complex reef-lagoon system of Moorea. The high foraminiferal Fisher α and species richness diversity in outer bay

  2. BENTHIC FORAMINIFERA IN SOUTH WAIGEO WATERS, RAJA AMPAT, WEST PAPUA

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    Suhartini M. Natsir

    2017-07-01

    Full Text Available Waigeo Island is one of four large islands of the Raja Ampat group, West Papua Province. This area lies in the heart of the coral triangle region as the most marine bio-diversity on Earth. Coral reef ecosystem of the Waigeo is a favorable habitat for various organisms including foraminifera. Foraminifera have been proven as useful indicator of water quality surrounding the coral reef environment since FORAM Index was formulated. It gives additional importance of foraminifera beside their common uses on micropalaeontology for petroleum industry and palaeoecology. Therefore, it is very important to obtain data of the benthic foraminifera from various coral reef environments in Indonesia, such as around Waigeo Island. Sediment samples of this study were collected from 12 sites in southern part off Waigeo Island, on July 2011. Observation on benthic foraminifera shows that the study area is dominated by symbiotic bearing benthic foraminifera, Amphistegina lessonii, belongs to Suborder Rotaliina. This occurrence increases the values of FORAM Index (FI at certain sites. Generally, the values of FI from most sites are high (FI>4 that provide a good indication for reef growth or recovery. The values of FI less than 2 are found at RJ3 and RJ4 indicate stress environment for reef growth and they are dominated by opportunistic and heterotrophic functional groups of Elphidium and Quinqueloculina.

  3. Microfacies analysis of foraminifera rich sedimentary rocks from the Desert Plateau, central Egypt.

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    Karnitschar, C.; Briguglio, A.; Hohenegger, J.

    2012-04-01

    Microfacies analysis on some samples from the Thebes Group have been carried on by means of thin sections. The study area is included in the Libyan Desert Plateau (central Egypt) at following coordinates N27° 36'30.58" E29° 44'58.34", near the biggest dune of Egypt, the Ghard Abu Muharik. Because of the round shape of the rocks and the desert patina on the surface they could easily be classified as the so called "Melonstones", which are located more southwards and mainly composed by stromatolites. On the contrary, the investigated samples show a completely different fauna and therefore have been separated from the "Melonstones". Even if shape and size are very similar and the desert patina covers all surfaces the same way the differences are impressive. To investigate the samples, two thin-sections have been prepared and analyzed at the microscope. The observed fauna is composed by: agglutinated benthic foraminifera (e.g., Dictyoconus egypticus), complex larger miliolids (e.g., Pseudolacazina cf. danatae, Fabularia sp.), alveolinids (Alveolina vredenburgi), green algae (Dasycladaceae), echinoids and corals. Because of the presence of symbionts bearing larger benthic foraminifera, which need light to feed photosymbionts, the rock was formed in a shallow water environment. With the abundant rock-building benthic foraminifera and calcareous algae the limestone shows a tendency to the packstone/wackestone facies. Based on the presence of Alveolina vredenburgi, the age of the samples can be estimate as lowermost Eocene belonging to the shallow benthic zone 5 (sensu Serra-Kiel et al., 1998). According the obtained data on stratigraphy and palaeoecology, a partial palaeoenvironmental reconstruction is possible for the Libyan Desert Plateau where outcrops are largely missing. Because of the round shape of the samples and the patina which covers them all around it can be assumed that they have been transported from longer distance. According to the geological map of the

  4. Biomineralization in Foraminifera

    Science.gov (United States)

    Nooijer, L. D.; Toyofuku, T.; Bijma, J.; Reichart, G. J.

    2014-12-01

    Foraminifera are popular tools for paleoceanograpic reconstructions since incorporation of numerous elements and fractionation of stable isotopes into their carbonate tests depend on environmental conditions. Their test chemistry is markedly different from that of inorganically precipitated CaCO3 (Figure), reflecting that calcification is a process under tight biological control. The cellular components responsible for calcification are only partly identified in foraminifera and include the involvement of organic templates, trans-membrane ion transporters and proton removal. Recent results have suggested that transmembrane H+ and Ca2+ transport is directly coupled and that a key feature of foraminiferal calcification is the intracellular conversion of bicarbonate into carbonate ions. Amongst others, this explains how some foraminifera are able to calcify in undersaturated seawater and may explain their moderate response to ocean acidification. Minor and trace metals incorporated into test carbonate reflect the processes involved in biomineralization and can thus be used to unravel the different factors and processes involved. Still, a more detailed understanding of the processes involved in foraminiferal calcification is needed to explain observed (inter-species) differences in partition coefficients for the incorporation of minor and trace metals and isotopic fractionation.

  5. Biomineralization in foraminifera

    Science.gov (United States)

    Nooijer, L. D.; Toyofuku, T.; Bijma, J.; Reichart, G. J.

    2015-12-01

    Foraminifera are popular tools in paleoceanography since incorporation of minor/ major elements and fractionation of stable isotopes into their carbonate shells depend on environmental conditions (e.g. temperature, salinity, pH). Their shell chemistry is markedly different from that of inorganically precipitated CaCO3, reflecting that calcification is a process under strong biological control. The cellular components responsible for calcification are only partly identified in foraminifera and include the involvement of organic templates, trans-membrane ion transporters and selective ion removal. Recent results suggest that transmembrane exchange of H+ for Ca2+ is directly responsible for calcification. The resulting high pH inside and lowered pH outside the foraminifer results in an efficient CO2 'trap' after which carbon dioxide is converted to carbonate prior to calcification. Amongst others, this explains how some foraminifera are able to calcify in undersaturated seawater and may explain their moderate response to ocean acidification. Minor and trace metals incorporated into test carbonate reflect the processes involved in biomineralization and can thus be used to unravel the different factors and processes involved. Still, a more detailed understanding of the processes involved in foraminiferal calcification is needed to explain observed (inter-species) differences in partition coefficients for the incorporation of minor and trace metals and isotopic fractionation.

  6. The 'Natural Laboratory', a tool for deciphering growth, lifetime and population dynamics in larger benthic foraminifera

    Science.gov (United States)

    Hohenegger, Johann

    2015-04-01

    The shells of symbiont-bearing larger benthic Foraminifera (LBF) represent the response to physiological requirements in dependence of environmental conditions. All compartments of the shell such as chambers and chamberlets accommodate the growth of the cell protoplasm and are adaptations for housing photosymbiotic algae. Investigations on the biology of LBF were predominantly based on laboratory studies. The lifetime of LBF under natural conditions is still unclear. LBF, which can build >100 chambers during their lifetime, are thought to live at least one year under natural conditions. This is supported by studies on population dynamics of eulittoral foraminifera. In species characterized by a time-restricted single reproduction period the mean size of specimens increases from small to large during lifetime simultaneously reducing individual number. This becomes more complex when two or more reproduction times are present within a one-year cycle leading to a mixture of abundant small individuals with few large specimens during the year, while keeping mean size more or less constant. This mixture is typical for most sublittoral megalospheric (gamonts or schizonts) LBF. Nothing is known on the lifetime of agamonts, the diploid asexually reproducing generation. In all hyaline LBF it is thought to be significantly longer than 1 year based on the large size and considering the mean chamber building rate of the gamont/schizonts. Observations on LBF under natural conditions have not been performed yet in the deeper sublittoral. This reflects the difficulties due to intense hydrodynamics that hinder deploying technical equipment for studies in the natural environment. Therefore, studying growth, lifetime and reproduction of sublittoral LBF under natural conditions can be performed using the so-called 'natural laboratory' in comparison with laboratory investigations. The best sampling method in the upper sublittoral from 5 to 70 m depth is by SCUBA diving. Irregular

  7. The effect of carbonate chemistry and light levels on calcification and photosynthesis in the larger benthic foraminifera Operculina ammonoides

    Science.gov (United States)

    Oron, Shai; Abramovich, Sigal; Evans, David; Erez, Jonathan

    2015-04-01

    We present data on metabolic measurements and growth experiments conducted on Operculina ammonoides, a symbiont bearing larger benthic foraminifera (LBF) of the family Nummulitidae, which is the closest living descendant of the Eocene Nummulites. The large size, the high abundance and wide distribution of Nummulitids and other LBF make them a vital archive for ancient and recent oceanic environments. LBF are also an important component of the ocean tropical and subtropical benthic ecosystem, where they have a significant contribution to primary production, and are major calcium carbonate producers. Their symbiosis, calcification physiology, and ecological response to environmental changes are poorly understood. The present study is part of an ongoing research effort focused on those topics. Calcification, respiration and symbiont photosynthesis were measured during long-term experiments that included manipulation of carbonate chemistry parameters and light levels. The experiments were done with large number of individuals (1500 in total) divided into incubation groups of 60-100. Diurnal and nocturnal data was obtained, along with cumulative incubations on a time span of a few days. The metabolic rates were estimated from measurements of dissolved oxygen, total alkalinity and pH before and after the incubations. This technique does not interfere with the experimental populations and allow a series of measurements to be performed on the same specimens. In all experiments, both for the diurnal cycles and for the long incubations, we observed significantly higher photosynthesis rates than respiration (positive O2 budget) for the holobiont. This oxygen excess has increased with light intensity, suggesting a significant growth of the symbionts within their host. Calcification was enhanced during the day compared to the night but did not increase with light intensity or with photosynthesis. In normal seawater, higher calcification rates were observed during the cumulative

  8. Ecology of planktonic foraminifera and their symbiotic algae

    International Nuclear Information System (INIS)

    Gastrich, M.D.

    1986-01-01

    Two types of symbiotic algae occurred abundantly and persistently in the cytoplasm of several species of planktonic Foraminifera over a ten year period in different tropical and subtropical areas of the North Atlantic Ocean. These planktonic Foraminifera host species consistently harbored either dinoflagellates or a newly described minute coccoid algal type. There appeared to be a specific host-symbiont relationship in these species regardless of year, season or geographic locality. The larger ovoid dinoflagellates (Pyrrhophycophyta) occur in the spinose species Globigerinoides ruber, Globigerinoides sacculifer, G. conglobatus and Orbulina universa. The smaller alga, from 1.5 to 3.5 um in diameter, occurs in one spinose species Globigerinella aequilateralis and also in the non-spinose species Globigerinita glutinata, Globoquadrina dutertrei, Globorotalia menardii, Globorotalia cristata, Globorotalia inflata, Candeina nitida, in various juvenile specimens and at all seasons except the winter months in Pulleniatina obliquiloculata and Globorotalial hirsuta. Controlled laboratory studies indicated a significant C incorporation into the host cytoplasm and inorganic calcium carbonate test of Globigerinoides ruber. During incubation for up to two hours, the 14 C uptake into the cytoplasm and test in the light was significantly greater than uptake in the dark by living specimens or by dead foraminifers. There appears to be light-enhanced uptake of 14 C into the test with dinoflagellate photosynthesis contributing to host calcification. In culture, symbiotic algae were observed to survive for the duration of the lifespan of their hosts

  9. An endemic post-CTB Pseudorhapydionina (foraminifera) from the Pyrenean palaeobioprovince

    Science.gov (United States)

    Consorti, Lorenzo; Caus, Esmeralda

    2015-04-01

    and Orbitokathina vonderschmitti, among others. All of this fauna that seems restricted to the Pyrenean palaeobioprovince are late Cretaceous GCMC newcomers. Thus, the presence of such morphotype in the deposits of the Late Cretaceous GCMC of the Pyrenean palaeobioprovincie arises the followings questions: is the Pyrenean taxon a CTB survivor? Or, are we faced with a morphological convergence? Positive answering to the first question would implicate that Pseudorhapydionina could have successfully migrated from the western Tethyan (Iberian Basin) to the Pyrenean Basin before the communication was stopped, without reaching an appropriate colonizing area, probably due to the different oceanographic conditions. But, the change of those conditions during the late Coniacian- early Santonian times, as it is demonstrated by the abundance of symbiont-bearing LBF taxa, had favored the installation of Pseudorhapydionina in the Santonian shallow-water environments. The hypothesis of a morphological convergence could be explained by the quite simple architecture of the present taxon. Notwithstanding, following the actual taxonomical classification in foraminifera, the presence of radial septula, which does not alternate with the intercameral foramina, and the absence of pillars definitively ascribed our specimens to the genus Pseudorhapydionina.

  10. Ecology and distribution of recent planktonic foraminifera in eastern part of Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Kutty, M.K.

    (0-200 m) than in the surface (0-10 m) tows. Further, latitudinal gradient of some species which have a definite bearing on hydrography of the sea, has been outlined. Relative production of planktonic foraminifera shows that it is high in the southern...

  11. Role of foraminifera in oceanographic events

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    assists in the correlation with foraminifera as indicators. The planktonic assemblages also show effects of climatic control on water masses as seen in some deep sea cores. Species like @iOrbulina universa, Neogloboquadrina pachyderma, Globorotalia...

  12. Foraminifera and changing pattern of monsoon rainfall

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    The palaeomonsoonal history can be reconstructed utilizing climatically sensitive properties of marine microorganisms; foraminifera. The results show a major boundary at 3500 years B.P. and periods of rather low precipitation approximately at 420...

  13. Evolution: Welcome to Symbiont Prison.

    Science.gov (United States)

    Kiers, E Toby; West, Stuart A

    2016-01-25

    Can egalitarian partnerships exist in nature? A new study demonstrates how protist hosts use and abuse their algal symbionts depending on their needs. While this relationship allows protists to survive in low nutrient conditions, it leaves little room for algal retaliation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. Evolution: Welcome to Symbiont Prison

    NARCIS (Netherlands)

    Kiers, E.T.; West, S.A.

    2016-01-01

    Can egalitarian partnerships exist in nature? A new study demonstrates how protist hosts use and abuse their algal symbionts depending on their needs. While this relationship allows protists to survive in low nutrient conditions, it leaves little room for algal retaliation.

  15. Insect symbionts in food webs

    Czech Academy of Sciences Publication Activity Database

    McLean, A. H. C.; Parker, B. J.; Hrček, Jan; Henry, L. M.; Godfray, H. C. J.

    2016-01-01

    Roč. 371, č. 1702 (2016), article number 20150325 ISSN 0962-8436 Institutional support: RVO:60077344 Keywords : food web * symbiont * symbiosis Subject RIV: EE - Microbiology, Virology Impact factor: 5.846, year: 2016 http://rstb.royalsocietypublishing.org/content/371/1702/20150325

  16. Benthic foraminifera in the plankton following storms: what does this mean for (palaeo)-ecological interpretations?

    Science.gov (United States)

    Hart, Malcolm; Molina, Giulia; Smart, Christopher; Widdicombe, Claire

    2017-04-01

    The Western Channel Observatory was established by the Natural Environment Research Council (NERC), with Plymouth Marine Laboratory managing the two autonomous buoys that are located to the south of Plymouth in the English Channel (Stations L4 and E1): see Smyth et al. (2015). These two locations are now monitored continually and there is regular sampling of the water column and the sea floor at both locations. At Station L4, despite being in waters with a depth of 50 m, benthic foraminifera are regularly found in the surface water plankton samples. Some of these benthic foraminifera contain algal symbionts, indicating that they may be living at the time of capture. If benthic foraminifera can be entrained in the water column, while still living, then this provides a mechanism for 'migration' that is much more rapid and efficient than the rate at which protists could migrate within, or on, the sediment surface. Recolonization by foraminifera, following disturbance, could well be facilitated by this mechanism which has only rarely been reported in the literature (e.g., Murray, 1965). It is clearly limited to depths impacted by fair weather ( 30 m) or storm wave base (80 - 100 m). Data gathered during winter 2015-2016 certainly indicate that, following storm events, the larger the number of benthic foraminifera in the plankton tows and the greater their overall size. Some of the individuals being observed appear to contain sediment, indicating that they have been picked up from the sediment surface and, despite their greater weight, have still been transported into the plankton. Using data from the nearby sea area, off-shore and within Plymouth Sound, we are trying to ascertain if the recorded assemblage is from the L4 area, or whether they have been transported out from shallower-water environments, possibly assisted by increased run-off caused by heavy rainfall (associated with the storms). Clearly, re-distribution of foraminifera in the environment might make

  17. Testing the Molecular Clock Using the Best Fossil Record: Case Studies from the Planktic Foraminifera

    Science.gov (United States)

    Steel, B. A.; Kucera, M.; Darling, K.

    2004-12-01

    Criticism of molecular clock studies often centres on inadequate calibration and a perceived lack of correlation between reproductive isolation and recognisable morphological evolution. Since many major groups (e.g. birds, mammals, reptiles) have a poor fossil record, it is often difficult to test and refute these limitations. Planktic foraminifera represent an exception to this rule. Deep-sea sediments are super-abundant in foraminifera, and large numbers of specimens and occurrences are easily garnered from Ocean Drilling Programme cores. Planktic foraminifera therefore represent an ideal model group with which to test and refine molecular clock studies. Since the 1990AƒAøAøâ_sA¬Aøâ_zAøs, genetic sequences (principally 18S r-RNA) have been extracted from living planktic foraminifera, and a large genetic library has developed. Our study attempts to contextualise and test molecular data, particularly AƒAøAøâ_sA¬Asmall amount of morphological evolution observed within the plexus. We have used morphometric methods on a large (over 2000 pooled specimens) dataset in an effort to independently test the molecular clock, using SEM-based measurement of pore metrics (for Gl. siphonifera) and a multivariate analysis of whole-test characteristics (for Gs. ruber). Comparison of results for the two species suggests interesting patterns; whilst the two cryptic sub-types of Gl. siphonifera seemingly can be traced through time and seem to respond to external oceanographic forcing, the sub-types of Gs. ruber appear to be truly cryptic, and cannot be distinguished in the fossil record beyond 0.7 Ma. This raises two important points; firstly, the molecular clock (at least for foraminifera) bears considerable scrutiny, appears to be relatively robust to substitution bias and is seemingly broadly in accordance with morphological data; and secondly, the relationship between form and function in planktic foraminifera appears to be ill-defined, raising important questions for

  18. Comparative metagenomics of Daphnia symbionts

    Directory of Open Access Journals (Sweden)

    Preston James F

    2009-04-01

    Full Text Available Abstract Background Shotgun sequences of DNA extracts from whole organisms allow a comprehensive assessment of possible symbionts. The current project makes use of four shotgun datasets from three species of the planktonic freshwater crustaceans Daphnia: one dataset from clones of D. pulex and D. pulicaria and two datasets from one clone of D. magna. We analyzed these datasets with three aims: First, we search for bacterial symbionts, which are present in all three species. Second, we search for evidence for Cyanobacteria and plastids, which had been suggested to occur as symbionts in a related Daphnia species. Third, we compare the metacommunities revealed by two different 454 pyrosequencing methods (GS 20 and GS FLX. Results In all datasets we found evidence for a large number of bacteria belonging to diverse taxa. The vast majority of these were Proteobacteria. Of those, most sequences were assigned to different genera of the Betaproteobacteria family Comamonadaceae. Other taxa represented in all datasets included the genera Flavobacterium, Rhodobacter, Chromobacterium, Methylibium, Bordetella, Burkholderia and Cupriavidus. A few taxa matched sequences only from the D. pulex and the D. pulicaria datasets: Aeromonas, Pseudomonas and Delftia. Taxa with many hits specific to a single dataset were rare. For most of the identified taxa earlier studies reported the finding of related taxa in aquatic environmental samples. We found no clear evidence for the presence of symbiotic Cyanobacteria or plastids. The apparent similarity of the symbiont communities of the three Daphnia species breaks down on a species and strain level. Communities have a similar composition at a higher taxonomic level, but the actual sequences found are divergent. The two Daphnia magna datasets obtained from two different pyrosequencing platforms revealed rather similar results. Conclusion Three clones from three species of the genus Daphnia were found to harbor a rich

  19. Automated species-level identification and segmentation of planktonic foraminifera using convolutional neural networks

    Science.gov (United States)

    Marchitto, T. M., Jr.; Mitra, R.; Zhong, B.; Ge, Q.; Kanakiya, B.; Lobaton, E.

    2017-12-01

    Identification and picking of foraminifera from sediment samples is often a laborious and repetitive task. Previous attempts to automate this process have met with limited success, but we show that recent advances in machine learning can be brought to bear on the problem. As a `proof of concept' we have developed a system that is capable of recognizing six species of extant planktonic foraminifera that are commonly used in paleoceanographic studies. Our pipeline begins with digital photographs taken under 16 different illuminations using an LED ring, which are then fused into a single 3D image. Labeled image sets were used to train various types of image classification algorithms, and performance on unlabeled image sets was measured in terms of precision (whether IDs are correct) and recall (what fraction of the target species are found). We find that Convolutional Neural Network (CNN) approaches achieve precision and recall values between 80 and 90%, which is similar precision and better recall than human expert performance using the same type of photographs. We have also trained a CNN to segment the 3D images into individual chambers and apertures, which can not only improve identification performance but also automate the measurement of foraminifera for morphometric studies. Given that there are only 35 species of extant planktonic foraminifera larger than 150 μm, we suggest that a fully automated characterization of this assemblage is attainable. This is the first step toward the realization of a foram picking robot.

  20. 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.

  1. Foraminifera size evolution through the Phanerozoic (Invited)

    Science.gov (United States)

    Ingram, K.; Tachiki, N.; Cummins, R.; Jost, A. B.; Payne, J.

    2009-12-01

    In this research project we wanted to find out how the body size of Foraminifera, small unicellular protists which most frequently live in marine environments, changed through the Phanerozoic Eon (the past 543 million years). We measured maximum test length in 2,637 different Foraminifera genera catalogued by Loeblich and Tappan (1988), and used those data to determine how their body size has evolved. We learned that Foraminiferan size correlates closely with mass extinction and major ocean anoxic events, test composition does not correlate well with body size, and that Berner’s (2006) Phanerozoic atmospheric oxygen concentration curve strongly correlates with mean test size.

  2. Rare earth element association with foraminifera

    Science.gov (United States)

    Roberts, Natalie L.; Piotrowski, Alexander M.; Elderfield, Henry; Eglinton, Timothy I.; Lomas, Michael W.

    2012-10-01

    Neodymium isotopes are becoming widely used as a palaeoceanographic tool for reconstructing the source and flow direction of water masses. A new method using planktonic foraminifera which have not been chemically cleaned has proven to be a promising means of avoiding contamination of the deep ocean palaeoceanographic signal by detrital material. However, the exact mechanism by which the Nd isotope signal from bottom waters becomes associated with planktonic foraminifera, the spatial distribution of rare earth element (REE) concentrations within the shell, and the possible mobility of REE ions during changing redox conditions, have not been fully investigated. Here we present REE concentration and Nd isotope data from mixed species of planktonic foraminifera taken from plankton tows, sediment traps and a sediment core from the NW Atlantic. We used multiple geochemical techniques to evaluate how, where and when REEs become associated with planktonic foraminifera as they settle through the water column, reside at the surface and are buried in the sediment. Analyses of foraminifera shells from plankton tows and sediment traps between 200 and 2938 m water depth indicate that only ˜20% of their associated Nd is biogenically incorporated into the calcite structure. The remaining 80% is associated with authigenic metal oxides and organic matter, which form in the water column, and remain extraneous to the carbonate structure. Remineralisation of these organic and authigenic phases releases ions back into solution and creates new binding sites, allowing the Nd isotope ratio to undergo partial equilibration with the ambient seawater, as the foraminifera fall through the water column. Analyses of fossil foraminifera shells from sediment cores show that their REE concentrations increase by up to 10-fold at the sediment-water interface, and acquire an isotopic signature of bottom water. Adsorption and complexation of REE3+ ions between the inner layers of calcite contributes

  3. Foraminifera from the Bay of Jakarta, Java

    NARCIS (Netherlands)

    Hofker, J.

    1968-01-01

    Foraminifera from the North coast of Java have been described by MILLET (1898-1904); by KEIJZER (1935). The Siboga Expedition did not sample on the Java coast; most of the species described by Millet were also collected elsewhere in the Indonesian Archipelago. Keijzer did not have the intention to

  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. Aphid Heritable Symbiont Exploits Defensive Mutualism.

    Science.gov (United States)

    Doremus, Matthew R; Oliver, Kerry M

    2017-04-15

    Insects and other animals commonly form symbioses with heritable bacteria, which can exert large influences on host biology and ecology. The pea aphid, Acyrthosiphon pisum , is a model for studying effects of infection with heritable facultative symbionts (HFS), and each of its seven common HFS species has been reported to provide resistance to biotic or abiotic stresses. However, one common HFS, called X-type, rarely occurs as a single infection in field populations and instead typically superinfects individual aphids with Hamiltonella defensa , another HFS that protects aphids against attack by parasitic wasps. Using experimental aphid lines comprised of all possible infection combinations in a uniform aphid genotype, we investigated whether the most common strain of X-type provides any of the established benefits associated with aphid HFS as a single infection or superinfection with H. defensa We found that X-type does not confer protection to any tested threats, including parasitoid wasps, fungal pathogens, or thermal stress. Instead, component fitness assays identified large costs associated with X-type infection, costs which were ameliorated in superinfected aphids. Together these findings suggest that X-type exploits the aphid/ H. defensa mutualism and is maintained primarily as a superinfection by "hitchhiking" via the mutualistic benefits provided by another HFS. Exploitative symbionts potentially restrict the functions and distributions of mutualistic symbioses with effects that extend to other community members. IMPORTANCE Maternally transmitted bacterial symbionts are widespread and can have major impacts on the biology of arthropods, including insects of medical and agricultural importance. Given that host fitness and symbiont fitness are tightly linked, inherited symbionts can spread within host populations by providing beneficial services. Many insects, however, are frequently infected with multiple heritable symbiont species, providing potential

  6. Incorporation of Mg and Sr in calcite of cultured benthic foraminifera: impact of calcium concentration and associated calcite saturation state

    Directory of Open Access Journals (Sweden)

    M. Raitzsch

    2010-03-01

    Full Text Available We investigated the effect of the calcium concentration in seawater and thereby the calcite saturation state (Ω on the magnesium and strontium incorporation into benthic foraminiferal calcite under laboratory conditions. For this purpose individuals of the shallow-water species Heterostegina depressa (precipitating high-Mg calcite, symbiont-bearing and Ammonia tepida (low-Mg calcite, symbiont-barren were cultured in media under a range of [Ca2+], but similar Mg/Ca ratios. Trace element/Ca ratios of newly formed calcite were analysed with Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS and normalized to the seawater elemental composition using the equation DTE=(TE/Cacalcite/(TE/Caseawater. The culturing study shows that DMg of A. tepida significantly decreases with increasing Ω at a gradient of −4.3×10−5 per Ω unit. The DSr value of A. tepida does not change with Ω, suggesting that fossil Sr/Ca in this species may be a potential tool to reconstruct past variations in seawater Sr/Ca. Conversely, DMg of H. depressa shows only a minor decrease with increasing Ω, while DSr increases considerably with Ω at a gradient of 0.009 per Ω unit. The different responses to seawater chemistry of the two species may be explained by a difference in the calcification pathway that is, at the same time, responsible for the variation in the total Mg incorporation between the two species. Since the Mg/Ca ratio in H. depressa is 50–100 times higher than that of A. tepida, it is suggested that the latter exhibits a mechanism that decreases the Mg/Ca ratio of the calcification fluid, while the high-Mg calcite forming species may not have this physiological tool. If the dependency of Mg incorporation on seawater [Ca2+] is also valid for deep

  7. TOF-SIMS characterization of planktonic foraminifera

    International Nuclear Information System (INIS)

    Vering, G.; Crone, C.; Bijma, J.; Arlinghaus, H.F.

    2003-01-01

    Oceanic sediment properties that are closely related to former environmental (e.g. climatic) parameters are called 'proxies'. Planktonic foraminifera are small protists which make up part of the plankton. Certain element concentrations, element ratios and isotopic ratios of their calcite shell found in the sediment can be used as proxies reflecting the state of the ocean during the life of the animal; they supply useful information for the reconstruction of environmental parameters. Time-of-flight secondary ion mass spectrometry (TOF-SIMS) was used to examine the inner and outer part of foraminiferal shells, as well as foraminiferal shells dissolved in HCl. High resolution elemental images and mass spectra were obtained from the foraminifera. The data show that TOF-SIMS is a useful technique for determining the elemental distribution and for measuring isotope ratios such as δ 11 B with high precision in a single foraminiferal shell

  8. The evolution of host-symbiont dependence

    NARCIS (Netherlands)

    Fisher, Roberta M.; Henry, Lee M.; Cornwallis, Charlie K.; Kiers, E. Toby; West, Stuart A.

    2017-01-01

    Organisms across the tree of life form symbiotic partnerships with microbes for metabolism, protection and resources. While some hosts evolve extreme dependence on their symbionts, others maintain facultative associations. Explaining this variation is fundamental to understanding when symbiosis can

  9. Stable carbon and oxygen isotope study on benthic foraminifera ...

    Indian Academy of Sciences (India)

    Ajoy K Bhaumik

    2017-07-24

    Jul 24, 2017 ... Stable isotopes of benthic foraminifera have widely been applied in micropalaeontological research to understand vital effects in foraminifera. Isotopic fractionations are mainly controlled by ontogeny, bottom/pore water chemistry, habitat preference, kinetic effect and respiration. Discontinuous abundance.

  10. Vertical distribution of living mangrove foraminifera from KwaZulu ...

    African Journals Online (AJOL)

    Previous intertidal foraminiferal studies have predominantly focused on assemblages in surface sediments (0–1 cm), with the rationale that surface assemblages reflect the modern-day environment. Foraminifera live infaunally and therefore there is a need to document the infaunal vertical distribution of living foraminifera to ...

  11. Co-niche construction between hosts and symbionts

    Indian Academy of Sciences (India)

    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 ...

  12. Co-niche construction between hosts and symbionts: ideas and ...

    Indian Academy of Sciences (India)

    2017-07-05

    Jul 5, 2017 ... 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 ...

  13. 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 ...

  14. Influence of microbial symbionts on insect pheromones.

    Science.gov (United States)

    Engl, Tobias; Kaltenpoth, Martin

    2018-03-22

    Covering: up to 2018Pheromones serve as chemical signals between individuals of the same species and play important roles for mate localization and mate choice as well as other social interactions in insects. A growing body of literature indicates that microbial symbionts can modulate their hosts' chemical profiles, mate choice decisions and social behavior. This modulation can occur by the direct biosynthesis of pheromone components or the provisioning of precursors, or through general changes in the metabolite pool of the host and its resource allocation into pheromone production. Here we review and discuss the contexts in which microbial modulation of intraspecific communication in insects occurs and emphasize cases in which microbes are known to affect the involved chemistry. The described examples for a symbiotic influence on mate attraction and mate choice, aggregation, nestmate and kin recognition highlight the context-dependent costs and benefits of these symbiotic interactions and the potential for conflict and manipulation among the interacting partners. However, despite the increasing number of studies reporting on symbiont-mediated effects on insect chemical communication, experimentally validated connections between the presence of specific symbionts, changes in the host's chemistry, and behavioral effects thereof, remain limited to very few systems, highlighting the need for increased collaborative efforts between symbiosis researchers and chemical ecologists to gain more comprehensive insights into the influence of microbial symbionts on insect pheromones.

  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. Intertidal foraminifera from Miramar-Caranzalem Shoreline, Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Birajdar, S.M.; Nigam, R.

    Quantitative analysis of foraminifera (entire and broken) revealed that Rotalina, composed of 29 species, constituted 95.18% while Miliolina, composed of 11 species, and Textulariina, with 5 species were poorly represented. Temperature, salinity...

  17. Counts of Foraminifera from Selected North Atlantic Cores, LDEO

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Counts of primarily planktonic foraminifera from Dr. W.F. Ruddiman and staff at the Lamont-Doherty Earth Observatory of Columbia University are included in these...

  18. Holocene benthonic foraminifera from the shelf sediments of Kerala coast

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.

    Of the 32 species of benthic foraminifera recovered here some show definite Indo-Pacific affinity. Ecological parameters which govern this offshore region are considered. Several species show similarities with those found in the Neogene while...

  19. Unlocking the biomineralization style and affinity of Paleozoic fusulinid foraminifera.

    Science.gov (United States)

    Dubicka, Zofia; Gorzelak, Przemysław

    2017-11-09

    Fusulinids are the most diverse, abundant and geographically widespread Paleozoic foraminifera which are widely considered to possess a "homogeneously microgranular" test microstructure composed of subangular grains of several micrometers in size. However, this texture appears to be a diagenetic artifact. Here we describe well-preserved Devonian calcareous fusulinids (Nanicella) from the Holy Cross Mountains (HCM) in central Poland. Foraminifera from Poland in which the primary nature of tests have not been masked by diagenesis are composed of low magnesium calcite spherical grains up to about 100 nanometers in diameter, identical to those observed in Recent and fossil hyaline foraminifera (Rotaliida, Globothalamea). These data call the paradigm of microgranular test microstructure of Foraminifera into question, and suggest a possible phylogenetic relationship between globothalamids and some fusulinids.

  20. Planktonic foraminifera from core tops of western equatorial Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Guptha, M.V.S.

    A set of seven core tops from western equatorial Indian ocean were analysed for planktonic foraminifera, which has yielded 20 planktonic foraminiferal species. Among them Globorotalia menardii, Globigerinoides sacculifer and G. ruber constitute...

  1. Living planktonic foraminifera of the Wadge bank, Northern Indian Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Panikkar, B.M.; Kutty, M.K.

    Twenty three species of living planktonic Foraminifera belonging to 11 genera have been studied from the Wadge Bank area off southern tip of the Indian peninsula. The fauna is characterized by species such as Globigerinoides conglobatus, G...

  2. Methane seep events of the southern Joetsu Knoll since middle Pleistocene based on benthic foraminifera

    Science.gov (United States)

    Oi, T.; Akiba, F.; Matsumoto, R.; Kakuwa, Y.

    2016-12-01

    Gas hydrates were collected at several sites off Joetsu which presented anomalous seismic structures. "Gas chimneys", major host structures for shallow gas hydrates, were recognized ROV off Joetsu in eastern margin of the Japan Sea, as were a number of active methane seeps. The assemblage components and carbon isotope of benthic foraminifera, which are ubiquitous in global marine settings, can indicate methane seep environments (Akimoto et al., 1994; Bhaumik and Gupta, 2007). Preliminary work by Oi et al. (2015) documented the obvious occurrences of methane related foraminifera, Rutherfordoides sp., in three core sediments recovered from Umitaka Spur, west Oki Trough and north Mogami Trough in the eastern margin of the Japan Sea, and found them to comprise the early part of the MIS 2, calculated to 28-25ka. These records suggest that active methane seep events might occur at the same time during early MIS 2, but were confined within the last 100ka. In this study, we analyzed benthic foraminiferal fossils from drilling core J04RB (core length 122 m; one of the gas hydrate bearing sites at a southern part of the Joetsu Knoll) in order to document methane seep events during the last 500ka. Firstly, we estimated sedimentation ages from diatom biostratigraphy and identification of Aso-1 tephra. Based on diatom components, we recognized a boundary between NPD (Neogene North Pacific diatom Zonations) 12 and NPD11, estimated at 300 ka (MIS8/9; Yanagisawa and Akiba, 1998). The bottom age was estimated to almost 530-560 ka (around MIS14) especially from the alternation with warm and cold diatom zones (Akiba et al., 2014). Secondary, we could suppose the paleoenvironments from benthic foraminifera as below. 1. The rare benthic foraminifera during the cold stages (MIS8, MIS10, and MIS12) indicate anoxic bottom conditions characteristic of falling sea level, just as with MIS 2. 2. We recognized the continuous distributions of tiny methane related specimens of Rutherfordoides sp

  3. 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.

  4. Potential applications of insect symbionts in biotechnology

    OpenAIRE

    Berasategui, A.; Shukla, S.; Salem, H.; Kaltenpoth, M.

    2016-01-01

    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 biote...

  5. 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.

  6. Bearing system

    Science.gov (United States)

    Kapich, Davorin D.

    1987-01-01

    A bearing system includes backup bearings for supporting a rotating shaft upon failure of primary bearings. In the preferred embodiment, the backup bearings are rolling element bearings having their rolling elements disposed out of contact with their associated respective inner races during normal functioning of the primary bearings. Displacement detection sensors are provided for detecting displacement of the shaft upon failure of the primary bearings. Upon detection of the failure of the primary bearings, the rolling elements and inner races of the backup bearings are brought into mutual contact by axial displacement of the shaft.

  7. Benthic foraminifera as pollution indices in the marine environment of west coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Setty, M.G.A.P.; Nigam, R.

    effects monitoring through Foraminifera. In the Thana Creek area, Bombay, the magnitude of corrosive effect, lower-than-normal ornamentation, deepening of grooves and sutural thickenings, enlargement of pores, widening of apertures in Foraminifera were...

  8. The intriguing relationship between coiling direction and reproductive mode in benthic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Rao, A.S.

    Changes in coiling direction in foraminifera have been used extensively as proxy data for paleoclimates. However, most of the studies centred around planktonic foraminifera, and various causes (including reproductive mode) were suggested for coiling...

  9. Horizontal Transmission of Intracellular Insect Symbionts via Plants

    Directory of Open Access Journals (Sweden)

    Ewa Chrostek

    2017-11-01

    Full Text Available Experimental evidence is accumulating that endosymbionts of phytophagous insects may transmit horizontally via plants. Intracellular symbionts known for manipulating insect reproduction and altering fitness (Rickettsia, Cardinium, Wolbachia, and bacterial parasite of the leafhopper Euscelidius variegatus have been found to travel from infected insects into plants. Other insects, either of the same or different species can acquire the symbiont from the plant through feeding, and in some cases transfer it to their progeny. These reports prompt many questions regarding how intracellular insect symbionts are delivered to plants and how they affect them. Are symbionts passively transported along the insect-plant-insect path, or do they actively participate in the process? How widespread are these interactions? How does symbiont presence influence the plant? And what conditions are required for the new infection to establish in an insect? From an ecological, evolutionary, and applied perspective, this mode of horizontal transmission could have profound implications if occurring frequently enough or if new stable symbiont infections are established. Transmission of symbionts through plants likely represents an underappreciated means of infection, both in terms of symbiont epidemiology and the movement of symbionts to new host species.

  10. Horizontal Transmission of Intracellular Insect Symbionts via Plants.

    Science.gov (United States)

    Chrostek, Ewa; Pelz-Stelinski, Kirsten; Hurst, Gregory D D; Hughes, Grant L

    2017-01-01

    Experimental evidence is accumulating that endosymbionts of phytophagous insects may transmit horizontally via plants. Intracellular symbionts known for manipulating insect reproduction and altering fitness ( Rickettsia, Cardinium, Wolbachia , and bacterial parasite of the leafhopper Euscelidius variegatus ) have been found to travel from infected insects into plants. Other insects, either of the same or different species can acquire the symbiont from the plant through feeding, and in some cases transfer it to their progeny. These reports prompt many questions regarding how intracellular insect symbionts are delivered to plants and how they affect them. Are symbionts passively transported along the insect-plant-insect path, or do they actively participate in the process? How widespread are these interactions? How does symbiont presence influence the plant? And what conditions are required for the new infection to establish in an insect? From an ecological, evolutionary, and applied perspective, this mode of horizontal transmission could have profound implications if occurring frequently enough or if new stable symbiont infections are established. Transmission of symbionts through plants likely represents an underappreciated means of infection, both in terms of symbiont epidemiology and the movement of symbionts to new host species.

  11. Adjustment of the deuterium measurement technique in foraminifera

    International Nuclear Information System (INIS)

    Zdanevitch, Isabelle

    1985-01-01

    Foraminifera are sea unicellular animals with a calcitic skeleton. The isotopic rate of this carbonate depends on the isotopic composition of seawater and on the temperature of the water in which foraminifera was living. This research thesis reports the study of sea water D/H rate in the case of hydrogenated materials. Four different hydrogenated compounds bonded to calcite have been extracted and separated. The analysis of this isotopic rate is performed in a continuous way during degassing by directly introducing hydrogen in the source of a mass spectrometer [fr

  12. Zoological exploration of the continental shelf of Surinam: The foraminifera of the shelf of Surinam and the Guyanas

    NARCIS (Netherlands)

    Hofker, J.

    1983-01-01

    INDEX Introduction.................................................................................................................................... P. 5 List of samples studied for Foraminifera .................................................................................... P. 7 Alphabetic

  13. 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.

  14. 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...

  15. 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...

  16. Foraminifera as bioindicators in coral reef assessment and monitoring: The foram index

    Science.gov (United States)

    Hallock, P.; Lidz, B.H.; Cockey-Burkhard, E. M.; Donnelly, K.B.

    2003-01-01

    Coral reef communities are threatened worldwide. Resource managers urgently need indicators of the biological condition of reef environments that can relate data acquired through remote-sensing, water-quality and benthic-community monitoring to stress responses in reef organisms. The "FORAM" (Foraminifera in Reef Assessment and Monitoring) Index (FI) is based on 30 years of research on reef sediments and reef-dwelling larger foraminifers. These shelled protists are ideal indicator organisms because: ??? Foraminifers are widely used as environmental and paleoenvironmental indicators in many contexts; ??? Reef-building, zooxanthellate corals and foraminifers with algal symbionts have similar water-quality requirements; ??? The relatively short life spans of foraminifers as compared with long-lived colonial corals facilitate differentiation between long-term water-quality decline and episodic stress events; ??? Foraminifers are relatively small and abundant, permitting statistically significant sample sizes to be collected quickly and relatively inexpensively, ideally as a component of comprehensive monitoring programs; and ??? Collection of foraminifers has minimal impact on reef resources. USEPA guidelines for ecological indicators are used to evaluate the FI. Data required are foraminiferal assemblages from surface sediments of reef-associated environments. The FI provides resource managers with a simple procedure for determining the suitability of benthic environments for communities dominated by algal symbiotic organisms. The FI can be applied independently, or incorporated into existing or planned monitoring efforts. The simple calculations require limited computer capabilities and therefore can be applied readily to reef-associated environments worldwide. In addition, the foraminiferal shells collected can be subjected to morphometric and geochemical analyses in areas of suspected heavy-metal pollution, and the data sets for the index can be used with other

  17. Benthic foraminifera from the Adriatic Sea : principles of phenotypic variation

    NARCIS (Netherlands)

    Jorissen, F.J.

    1988-01-01

    The distribution and morphology of the benthic foraminifera in the Adriatic Sea appear to be strongly dependent on two primary controlling environmental parameters, oxygen concentration and food availability. These factors are both governed by the runoff from the Po and other Italian rivers, and

  18. Stable carbon and oxygen isotope study on benthic foraminifera ...

    Indian Academy of Sciences (India)

    The present study is pursued on isotopic values of different pairs of benthic foraminifera from the Krishna–Godavari basin and Peru offshore to understand habitat-wise isotopic variation and ... Department of Applied Geology, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand 826 004, India.

  19. Rare and remarkable Foraminifera of the Caribbean Sea

    NARCIS (Netherlands)

    Hofker, J.

    1979-01-01

    When studying samples from the Virgin Islands area, some new Foraminifera were found, together with other species of which little was known about their internal structure and taxonomic status. Most specimens came from samples W of St. Croix, collected by Th. Mortensen at about 17.5°N 64°W, depths

  20. Ecological partitioning and diversity in tropical planktonic foraminifera

    Directory of Open Access Journals (Sweden)

    Seears Heidi A

    2012-04-01

    Full Text Available Abstract Background Ecological processes are increasingly being viewed as an important mode of diversification in the marine environment, where the high dispersal potential of pelagic organisms, and a lack of absolute barriers to gene flow may limit the occurrence of allopatric speciation through vicariance. Here we focus on the potential role of ecological partitioning in the diversification of a widely distributed group of marine protists, the planktonic foraminifera. Sampling was conducted in the tropical Arabian Sea, during the southwest (summer monsoon, when pronounced environmental conditions result in a strong disparity in temperature, salinity and productivity between distinct northern and southern water masses. Results We uncovered extensive genetic diversity within the Arabian Sea planktonic foraminifera, identifying 13 morphospecies, represented by 20 distinct SSU rRNA genetic types. Several morphospecies/genetic types displayed non-random biogeographical distributions, partitioning between the northern and southern water masses, giving a strong indication of independent ecological adaptations. Conclusions We propose sea-surface primary productivity as the main factor driving the geographical segregation of Arabian Sea planktonic foraminifera, during the SW monsoon, with variations in symbiotic associations possibly playing a role in the specific ecological adaptations observed. Our findings suggest that ecological partitioning could be contributing to the high levels of 'cryptic' genetic diversity observed within the planktonic foraminifera, and support the view that ecological processes may play a key role in the diversification of marine pelagic organisms.

  1. Magnetic Bearing

    OpenAIRE

    Anbuselvan. T; Vinothkumar. K; Sai Vikash. M

    2013-01-01

    The use of bearings is essential to all types of machines, especially in marine aspects they provide the function of supporting heavier component in a desired position. These bearings have contact with the rotating part and causes surface wear which can be controlled by lubrication. Researches have raised the standards of performance for rotating equipment by providing robust, cost effective, easy to implement magnetic bearing solutions. Use of magnetic bearings in ships can be more advantag...

  2. Acetic Acid Bacteria as Symbionts of Insects

    KAUST Repository

    Crotti, Elena

    2016-06-14

    Acetic acid bacteria (AAB) are being increasingly described as associating with different insect species that rely on sugar-based diets. AAB have been found in several insect orders, among them Diptera, Hemiptera, and Hymenoptera, including several vectors of plant, animal, and human diseases. AAB have been shown to associate with the epithelia of different organs of the host, they are able to move within the insect’s body and to be transmitted horizontally and vertically. Here, we review the ecology of AAB and examine their relationships with different insect models including mosquitoes, leafhoppers, and honey bees. We also discuss the potential use of AAB in symbiont-based control strategies, such as “Trojan-horse” agents, to block the transmission of vector-borne diseases.

  3. Saprotrophic fungal mycorrhizal symbionts in achlorophyllous orchids

    Science.gov (United States)

    Martos, Florent; Perry, Brian A; Padamsee, Mahajabeen; Roy, Mélanie; Pailler, Thierry

    2010-01-01

    Mycoheterotrophic plants are achlorophyllous plants that obtain carbon from their mycorrhizal fungi. They are usually considered to associate with fungi that are (1) specific of each mycoheterotrophic species and (2) mycorrhizal on surrounding green plants, which are the ultimate carbon source of the entire system. Here we review recent works revealing that some mycoheterotrophic plants are not fungal-specific, and that some mycoheterotrophic orchids associate with saprophytic fungi. A re-examination of earlier data suggests that lower specificity may be less rare than supposed in mycoheterotrophic plants. Association between mycoheterotrophic orchids and saprophytic fungi arose several times in the evolution of the two partners. We speculate that this indirectly illustrates why transition from saprotrophy to mycorrhizal status is common in fungal evolution. Moreover, some unexpected fungi occasionally encountered in plant roots should not be discounted as ‘molecular scraps’, since these facultatively biotrophic encounters may evolve into mycorrhizal symbionts in some other plants. PMID:20061806

  4. 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.

    2016-01-01

    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. PMID:26911963

  5. Journal bearing

    Science.gov (United States)

    Menke, John R.; Boeker, Gilbert F.

    1976-05-11

    1. An improved journal bearing comprising in combination a non-rotatable cylindrical bearing member having a first bearing surface, a rotatable cylindrical bearing member having a confronting second bearing surface having a plurality of bearing elements, a source of lubricant adjacent said bearing elements for supplying lubricant thereto, each bearing element consisting of a pair of elongated relatively shallowly depressed surfaces lying in a cylindrical surface co-axial with the non-depressed surface and diverging from one another in the direction of rotation and obliquely arranged with respect to the axis of rotation of said rotatable member to cause a flow of lubricant longitudinally along said depressed surfaces from their distal ends toward their proximal ends as said bearing members are rotated relative to one another, each depressed surface subtending a radial angle of less than 360.degree., and means for rotating said rotatable bearing member to cause the lubricant to flow across and along said depressed surfaces, the flow of lubricant being impeded by the non-depressed portions of said second bearing surface to cause an increase in the lubricant pressure.

  6. 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

    . Although several studies have addressed the Verminephrobacter diversity between worm species, the intra-species diversity of the symbiont population has never been investigated. To address symbiont population structure, we used a multi-locus sequence typing (MLST) approach on Verminephrobacter isolated...... 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...... across host individuals from the same population. Thus, host ecology shapes the population structure of the Verminephrobacter symbionts. The homogeneous symbiont populations in the compost worms indicate that Verminephrobacter can be transferred bi-parentally or via leaky horizontal transmission in high...

  7. Foraminiferal assemblage in the coral-bearing limestones of the Vršatec area (Pieniny Klippen Belt, Western Carpathians, Slovakia)

    Science.gov (United States)

    Morycowa, Elżbieta; Olszewska, Barbara

    2013-02-01

    The paper deals with benthic foraminifera occurring with the scleractinian corals in the Jurassic biohermal and peribiohermal coral-bearing limestones of the Vršatec area (Czorsztyn Succession, Slovak Pieniny Klippen Belt). The coral community is dominated by branching forms of the genus Thecosmilia. Co-occurring abundant benthic foraminifera belong to the species Rumanolina seiboldi, R. elevata, Paalzowella turbinella and Troglotella incrustans. The coral-bearing limestones were initially assigned to the Oxfordian on the basis of the microfacies analyses and bivalve and scleractinian faunas. In recent papers they are assigned to the Bajocian on the basis of ammonites found in the neptunic dykes and stratigraphic superimposition criteria. However, the stratigraphic distribution of the majority of the identified foraminifera indicates that like most scleractinian coral taxa they are not known earlier than in the Late Jurassic. The Late Jurassic age of these coral-bearing limestones is also suggested by an encrusting microproblematic organism Iberopora bodeuri.

  8. Parasitic wasp responses to symbiont-based defense in aphids

    Directory of Open Access Journals (Sweden)

    Oliver Kerry M

    2012-02-01

    Full Text Available Abstract Background Recent findings indicate that several insect lineages receive protection against particular natural enemies through infection with heritable symbionts, but little is yet known about whether enemies are able to discriminate and respond to symbiont-based defense. The pea aphid, Acyrthosiphon pisum, receives protection against the parasitic wasp, Aphidius ervi, when infected with the bacterial symbiont Hamiltonella defensa and its associated bacteriophage APSE (Acyrthosiphon pisum secondary endosymbiont. Internally developing parasitoid wasps, such as A. ervi, use maternal and embryonic factors to create an environment suitable for developing wasps. If more than one parasitoid egg is deposited into a single aphid host (superparasitism, then additional complements of these factors may contribute to the successful development of the single parasitoid that emerges. Results We performed experiments to determine if superparasitism is a tactic allowing wasps to overcome symbiont-mediated defense. We found that the deposition of two eggs into symbiont-protected aphids significantly increased rates of successful parasitism relative to singly parasitized aphids. We then conducted behavioral assays to determine whether A. ervi selectively superparasitizes H. defensa-infected aphids. In choice tests, we found that A. ervi tends to deposit a single egg in uninfected aphids, but two or more eggs in H. defensa-infected aphids, indicating that oviposition choices may be largely determined by infection status. Finally, we identified differences in the quantity of the trans-β-farnesene, the major component of aphid alarm pheromone, between H. defensa-infected and uninfected aphids, which may form the basis for discrimination. Conclusions Here we show that the parasitic wasp A. ervi discriminates among symbiont-infected and uninfected aphids, and changes its oviposition behavior in a way that increases the likelihood of overcoming symbiont

  9. 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

  10. 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

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

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    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.

  12. KEANEKARAGAMAN FORAMINIFERA BENTIK TELUK BALIKPAPAN, PROVINSI KALIMANTAN TIMUR

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    MASTUTI WIDIANINGSIH

    2017-12-01

    Full Text Available Balikpapan Bay is one of locations of sampling sediments for the study of benthic foraminifera. The objective of this research was to determine the diversity of benthic foraminifera at different depths at Balikpapan Bay, East Kalimantan. Samples was selected at  depth of 0-20 m, then divided into 4 depths, 0-5 m, 6-10 m, 11-15 m, and 16-20 m. A total of 1553 specimens were obtained from 66 species, 7 ordo, and 17 family. Asterorotalia trispinosa is a species with the highest of abundance, that followed by Rotalia sp.1, Rotalia sp.2, and Trichammina nana. The diversity index of each sampling point was different, 8 points have stable diversity, 11 moderate points, and 1 unstable point. This condition were influenced by depth, brightness, temperature, pH, turbidity, salinity, and DO at each sediment sampling point.

  13. The evolution of test size in the Planktic Foraminifera

    Science.gov (United States)

    Fraass, A.; Huber, B. T.; Kelly, D. C.

    2017-12-01

    Planktic foraminifera are vital tools for understanding paleoceanography, paleoclimate, and evolution. A dataset of measurements from all planktic foraminiferal species is used here to investigate how their size changes through the late Jurassic to Recent. The mean test size of planktic foraminifera increases in the Cretaceous and the Cenozoic, with substantial drops at the Aptian/Albian boundary, in the Coniacian and Santonian, with the end-Cretaceous extinction, and across the Paleocene/Eocene boundary. The Oligocene contains only a small drop in mean size, which is surprising given the substantial extinction of planktic foraminifera at that boundary. There is a qualitative connection between mean and median size and paleoceanographic events, but several key issues remain before rigorous quantitative interrogation of the dataset can be undertaken. In general, species that originate early in a family's range are smaller than those evolving later, though this is a weak relationship. Individual families do not always conform to that finding, however, and have both increasing and decreasing family age-size relationships. The 'three faunas' concept for foraminiferal evolution fails with respect to mean and median size; each diversification has a unique rate of increase and character. Lastly, through comparison with the Schmidt et al. (2004) population-level test size dataset, the size response to climate in the low-latitudes is at the species-level. In the high-latitude regions, however, the response to climate is at the population level. Thus, methods for uncovering climate responses in planktic foraminifera must be specific to the region. Taxonomic or macroevolutionary responses dominate the tropics and global signals, while the polar regions appear to have a unique, and more microevolutionary response.Schmidt, D., Thierstein, H., Bollmann, J., & Schiebel, R. (2004). Abiotic Forcing of Plankton Evolution in the Cenozoic. Science, 303(5655), 207-210.

  14. Planktic foraminifera form their shells via metastable carbonate phases

    OpenAIRE

    Jacob, D. E.; Wirth, R.; Agbaje, O. B. A.; Branson, O.; Eggins, S. M.

    2017-01-01

    The calcium carbonate shells of planktic foraminifera provide our most valuable geochemical archive of ocean surface conditions and climate spanning the last 100 million years, and play an important role in the ocean carbon cycle. These shells are preserved in marine sediments as calcite, the stable polymorph of calcium carbonate. Here, we show that shells of living planktic foraminifers Orbulina universa and Neogloboquadrina dutertrei originally form from the unstable calcium carbonate polym...

  15. Factors controlling the depth habitat of planktonic foraminifera in the subtropical eastern North Atlantic

    Science.gov (United States)

    Rebotim, Andreia; Voelker, Antje H. L.; Jonkers, Lukas; Waniek, Joanna J.; Meggers, Helge; Schiebel, Ralf; Fraile, Igaratza; Schulz, Michael; Kucera, Michal

    2017-02-01

    Planktonic foraminifera preserved in marine sediments archive the physical and chemical conditions under which they built their shells. To interpret the paleoceanographic information contained in fossil foraminifera, the recorded proxy signals have to be attributed to the habitat and life cycle characteristics of individual species. Much of our knowledge on habitat depth is based on indirect methods, which reconstruct the depth at which the largest portion of the shell has been calcified. However, habitat depth can be best studied by direct observations in stratified plankton nets. Here we present a synthesis of living planktonic foraminifera abundance data in vertically resolved plankton net hauls taken in the eastern North Atlantic during 12 oceanographic campaigns between 1995 and 2012. Live (cytoplasm-bearing) specimens were counted for each depth interval and the vertical habitat at each station was expressed as average living depth (ALD). This allows us to differentiate species showing an ALD consistently in the upper 100 m (e.g., Globigerinoides ruber white and pink), indicating a shallow habitat; species occurring from the surface to the subsurface (e.g., Globigerina bulloides, Globorotalia inflata, Globorotalia truncatulinoides); and species inhabiting the subsurface (e.g., Globorotalia scitula and Globorotalia hirsuta). For 17 species with variable ALD, we assessed whether their depth habitat at a given station could be predicted by mixed layer (ML) depth, temperature in the ML and chlorophyll a concentration in the ML. The influence of seasonal and lunar cycle on the depth habitat was also tested using periodic regression. In 11 out of the 17 tested species, ALD variation appears to have a predictable component. All of the tested parameters were significant in at least one case, with both seasonal and lunar cyclicity as well as the environmental parameters explaining up to > 50 % of the variance. Thus, G. truncatulinoides, G. hirsuta and G. scitula

  16. MIDDLE TRIASSIC FORAMINIFERA FROM THE SECEDA CORE (DOLOMITES, NORTHERN ITALY

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    FLORIAN MAURER

    2002-11-01

    Full Text Available The assemblage of foraminifera in turbidite beds in Middle Triassic basinal deposits straddling the Anisian/Ladinian boundary interval was studied in 224 thin sections. The fauna consists mainly of shallow-water inhabitants, associated with calcareous hyaline foraminifera (Lagenina of open marine environment. Due to a well established  biostratigraphy in the studied interval, the first and last appearance of some shallow water, benthic foraminifera can be assigned to the Mid Triassic ammonoid stratigraphy. The species Meandrospira dinarica Kochansky-Devidè & Pantic and Arenovidalina chialingchiagensis Ho are limited to the Reitzi ammonoid zone. The species Variostoma alta Kristan and Hoyenella gr. sinensis both do not superate the Curionii zone in age in the studied succession.  The biostratigraphic most important event occurs at the base of the Gredleri zone,  with the appearance of the family Involutinidae Bütschli, represented by the genera Lamelliconus and Aulotortus. The faunal composition is similar to those of neighbouring paleoprovinces, but generally a lower faunistical diversification compared to foraminiferal assemblages in the Anisian or Carnian is observed.   

  17. GAS BEARING

    Science.gov (United States)

    Skarstrom, C.W.

    1960-09-01

    A gas lubricated bearing for a rotating shaft is described. The assembly comprises a stationary collar having an annular member resiliently supported thereon. The collar and annular member are provided with cooperating gas passages arranged for admission of pressurized gas which supports and lubricates a bearing block fixed to the rotatable shaft. The resilient means for the annular member support the latter against movement away from the bearing block when the assembly is in operation.

  18. Thrust bearing

    Science.gov (United States)

    Anderson, W. J. (Inventor)

    1976-01-01

    A gas lubricated thrust bearing is described which employs relatively rigid inwardly cantilevered spokes carrying a relatively resilient annular member or annulus. This annulus acts as a beam on which are mounted bearing pads. The resilience of the beam mount causes the pads to accept the load and, with proper design, responds to a rotating thrust-transmitting collar by creating a gas film between the pads and the thrust collar. The bearing may be arranged for load equalization thereby avoiding the necessity of gimbal mounts or the like for the bearing. It may also be arranged to respond to rotation in one or both directions.

  19. Agglutinated foraminifera from the Ludlow (Silurian) of Ireland

    Science.gov (United States)

    Kaminski, Michael; Ferretti, Annalisa; Messori, Fabio; Papazzoni, Cesare Andrea; Sevastopulo, George

    2017-04-01

    Agglutinated foraminifera are one of the most primitive groups of foraminifera, possibly already appearing in the Cryogenian but usually rare in lower Paleozoic rocks. Their mean standing diversity slowly increased during Cambrian and Ordovician times, reaching a stable value of about 50 genera in the mid-Silurian which remained fairly constant up to the Triassic. An assemblage of agglutinated foraminifera was unexpectedly found in conodont residue from material collected in the Dingle Peninsula, County Kerry, southwestern Ireland. This material comes from rare calcareous occurrences in volcanoclastics previously known for their rich trilobite and conodont assemblages. The limestones are trilobite-crinoidal silty wackestone to packstone, with local brachiopod concentrations, documenting brachiopod-trilobite-crinoidal dominated communities of shallow and well-ventilated water that might have periodically colonized the bottom intercalating with volcanic events and then successively redeposited in deeper waters. The conodont fauna indicates an early Ludlow (Gorstian-earliest Ludfordian) age (Kaminski et al., 2016). The foraminiferal assemblage has limited potential for stratigraphical correlation as long-range taxa are present, but it represents the first record from the Silurian of Ireland. The assemblage is dominated by tubothalamids (Rectoammodiscus and rare Sansabaina), with less abundant monothalamids (Psammosiphonella and Psammosphaera). The assemblage displays low diversity compared with other assemblages described from the British Isles (Kircher & Brasier, 1989). At the species level, this assemblage is identical to those described previously from the Silurian of North America but with lower diversity. Only Rectoammodiscus diai had apparently a wider geographic distribution, including not only the central USA (Oklahoma and Kansas) but also the Welsh Borderlands and Senegal. The affinities with the assemblages reported at several localities in the central

  20. Polar Bears

    Science.gov (United States)

    Amstrup, Steven C.; Douglas, David C.; Reynolds, Patricia E.; Rhode, E.B.

    2002-01-01

    Polar bears (Ursus maritimus) are hunted throughout most of their range. In addition to hunting polar bears of the Beaufort Sea region are exposed to mineral and petroleum extraction and related human activities such as shipping road-building, and seismic testing (Stirling 1990).Little was known at the start of this project about how polar bears move about in their environment, and although it was understood that many bears travel across political borders, the boundaries of populations had not been delineated (Amstrup 1986, Amstrup et al. 1986, Amstrup and DeMaster 1988, Garner et al. 1994, Amstrup 1995, Amstrup et al. 1995, Amstrup 2000).As human populations increase and demands for polar bears and other arctic resources escalate, managers must know the sizes and distributions of the polar bear populations. Resource managers also need reliable estimates of breeding rates, reproductive intervals, litter sizes, and survival of young and adults.Our objectives for this research were 1) to determine the seasonal and annual movements of polar bears in the Beaufort Sea, 2) to define the boundaries of the population(s) using this region, 3) to determine the size and status of the Beaufort Sea polar bear population, and 4) to establish reproduction and survival rates (Amstrup 2000).

  1. Quality or quantity: is nutrient transfer driven more by symbiont identity and productivity than by symbiont abundance?

    Science.gov (United States)

    Freeman, Christopher J; Thacker, Robert W; Baker, David M; Fogel, Marilyn L

    2013-06-01

    By forming symbiotic interactions with microbes, many animals and plants gain access to the products of novel metabolic pathways. We investigated the transfer of symbiont-derived carbon and nitrogen to the sponges Aplysina cauliformis, Aplysina fulva, Chondrilla caribensis, Neopetrosia subtriangularis and Xestospongia bocatorensis, all of which host abundant microbial populations, and Niphates erecta, which hosts a sparse symbiont community. We incubated sponges in light and dark bottles containing seawater spiked with (13)C- and (15)N-enriched inorganic compounds and then measured (13)C and (15)N enrichment in the microbial (nutrient assimilation) and sponge (nutrient transfer) fractions. Surprisingly, although most sponges hosting abundant microbial communities were more enriched in (13)C than N. erecta, only N. subtriangularis was more enriched in (15)N than N. erecta. Although photosymbiont abundance varied substantially across species, (13)C and (15)N enrichment was not significantly correlated with photosymbiont abundance. Enrichment was significantly correlated with the ratio of gross productivity to respiration (P:R), which varied across host species and symbiont phylotype. Because irradiance impacts P:R ratios, we also incubated A. cauliformis in (13)C-enriched seawater under different irradiances to determine whether symbiont carbon fixation and transfer are dependent on irradiance. Carbon fixation and transfer to the sponge host occurred in all treatments, but was greatest at higher irradiances and was significantly correlated with P:R ratios. Taken together, these results demonstrate that nutrient transfer from microbial symbionts to host sponges is influenced more by host-symbiont identities and P:R ratios than by symbiont abundance.

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

    Science.gov (United States)

    Ngugi, David Kamanda; Miyake, Sou; Cahill, Matt; Vinu, Manikandan; Hackmann, Timothy J; Blom, Jochen; Tietbohl, Matthew D; Berumen, Michael L; Stingl, Ulrich

    2017-09-05

    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, " Candidatus Epulopiscium" and related giant bacteria. These symbionts lack cellulases but encode a distinctive and lineage-specific array of mostly intracellular carbohydrases concurrent with the unique and tractable dietary resources of their hosts. Importantly, enzymes initiating the breakdown of the abundant and complex algal polysaccharides also originate from these symbionts. These are also highly transcribed and peak according to the diel lifestyle of their host, further supporting their importance and host-symbiont cospeciation. Because of their distinctive genomic blueprint, we propose the classification of these giant bacteria into three candidate genera. Collectively, our findings show that the acquisition of metabolically distinct " Epulopiscium " symbionts in hosts feeding on compositionally varied algal diets is a key niche-partitioning driver in the nutritional ecology of herbivorous surgeonfishes.

  3. Host-Symbiont Interactions for Potentially Managing Heteropteran Pests

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    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.

  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. Bipolar gene flow in deep-sea benthic foraminifera

    DEFF Research Database (Denmark)

    Pawlowski, J.; Fahrni, J.; Lecroq, B.

    2007-01-01

    Despite its often featureless appearance, the deep-ocean floor includes some of the most diverse habitats on Earth. However, the accurate assessment of global deep-sea diversity is impeded by a paucity of data on the geographical ranges of bottom-dwelling species, particularly at the genetic level....... Here, we present molecular evidence for exceptionally wide distribution of benthic foraminifera, which constitute the major part of deep-sea meiofauna. Our analyses of nuclear ribosomal RNA genes revealed high genetic similarity between Arctic and Antarctic populations of three common deep...

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

    Directory of Open Access Journals (Sweden)

    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

  7. Long‑term ungulate exclusion reduces fungal symbiont prevalence in native grasslands

    Science.gov (United States)

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

    2016-01-01

    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 <100 %, few studies investigate the ecological drivers of variation in symbiont prevalence. In plants, inherited fungal endophytes can...

  8. Benthic Foraminifera from the Capricorn Group, Great Barrier Reef, Australia.

    Science.gov (United States)

    Mamo, Briony L

    2016-12-23

    Effective reef management and monitoring has become increasingly important as anthropogenic processes impact upon natural ecosystems. One locality that is under direct threat due to human activities is the Australian Great Barrier Reef (GBR). Marine foraminifera represent an abundant and readily applicable tool that can be used in reef studies to investigate a variety of ecological parameters and assist in understanding reef dynamics and influence management protocols. The first step is to establish a baseline knowledge of taxonomic composition within the region to facilitate comparative studies and monitor how assemblages change in order to maximise effective management. A detailed taxonomic assessment is provided of 133 species of benthic foraminifera in 76 genera from Heron Island, One Tree Island, Wistari and Sykes Reefs, which form the core of the Capricorn Group (CG) at the southern end of the GBR. Of these 133 species, 46% belong to the order Miliolida, 34% to Rotaliida, 7% to Textulariida, 5% to Lagenida, 3% to Lituolida, 3% to Spirillinida, 1% to Loftusiida and 1% to Robertinida. Samples were collected from a variety of shallow shelf reef environments including reef flat, lagoonal and channel environments. Seventy species, representing the most abundant forms, are formally described with detailed distribution data for the remaining 63 species supplied.

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

    Science.gov (United States)

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

    2006-01-01

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

  10. Antibiotics, primary symbionts and wing polyphenism in three aphid species.

    Science.gov (United States)

    Hardie, Jim; Leckstein, Peter

    2007-08-01

    The possible role of the primary Buchnera symbionts in wing polyphenism is examined in three aphid species. Presumptive winged aphids were fed on antibiotic-treated beans to destroy these symbionts. As previously reported, this leads to inhibited growth and low/zero fecundity. When such treatment is applied to the short-day-induced gynoparae (the winged autumn migrant) of the black bean aphid, Aphis fabae, it also causes many insects to develop as wingless or winged/wingless intermediate adult forms (apterisation). However, whilst antibiotic treatment of crowd-induced, long-day winged forms of the pea aphid, Acyrthosiphon pisum (a green and a pink clone) and the vetch aphid, Megoura viciae has similar effects on size and fecundity, it does not affect wing development. Food deprivation also promotes apterisation in A. fabae gynoparae but not in the crowd-induced winged morphs of the other two species. Thus, it appears that apterisation in A. fabae is not a direct effect of antibiotic treatment or a novel role for symbionts but is most likely related to impaired nutrition induced by the loss of the symbiont population.

  11. 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...

  12. 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...

  13. Symbiont Dependent Thermal Bleaching Susceptiblity in Two Reef ...

    African Journals Online (AJOL)

    Symbiont Dependent Thermal Bleaching Susceptiblity in Two Reef-building Corals, Stylophora pistillata and Platygyra ryukyuensis . ... Symbiodinium ITS2 types exhibit diverse photo-physiological responses to thermal stress, and may partially explain the variable bleaching susceptibilities of some hermatypic coral species.

  14. Automatic Picking of Foraminifera: Design of the Foraminifera Image Recognition and Sorting Tool (FIRST) Prototype and Results of the Image Classification Scheme

    Science.gov (United States)

    de Garidel-Thoron, T.; Marchant, R.; Soto, E.; Gally, Y.; Beaufort, L.; Bolton, C. T.; Bouslama, M.; Licari, L.; Mazur, J. C.; Brutti, J. M.; Norsa, F.

    2017-12-01

    Foraminifera tests are the main proxy carriers for paleoceanographic reconstructions. Both geochemical and taxonomical studies require large numbers of tests to achieve statistical relevance. To date, the extraction of foraminifera from the sediment coarse fraction is still done by hand and thus time-consuming. Moreover, the recognition of morphotypes, ecologically relevant, requires some taxonomical skills not easily taught. The automatic recognition and extraction of foraminifera would largely help paleoceanographers to overcome these issues. Recent advances in automatic image classification using machine learning opens the way to automatic extraction of foraminifera. Here we detail progress on the design of an automatic picking machine as part of the FIRST project. The machine handles 30 pre-sieved samples (100-1000µm), separating them into individual particles (including foraminifera) and imaging each in pseudo-3D. The particles are classified and specimens of interest are sorted either for Individual Foraminifera Analyses (44 per slide) and/or for classical multiple analyses (8 morphological classes per slide, up to 1000 individuals per hole). The classification is based on machine learning using Convolutional Neural Networks (CNNs), similar to the approach used in the coccolithophorid imaging system SYRACO. To prove its feasibility, we built two training image datasets of modern planktonic foraminifera containing approximately 2000 and 5000 images each, corresponding to 15 & 25 morphological classes. Using a CNN with a residual topology (ResNet) we achieve over 95% correct classification for each dataset. We tested the network on 160,000 images from 45 depths of a sediment core from the Pacific ocean, for which we have human counts. The current algorithm is able to reproduce the downcore variability in both Globigerinoides ruber and the fragmentation index (r2 = 0.58 and 0.88 respectively). The FIRST prototype yields some promising results for high

  15. Pigments Characterization and Molecular Identification of Bacterial Symbionts of Brown Algae Padinasp. Collected from Karimunjawa Island

    Directory of Open Access Journals (Sweden)

    Damar Bayu Murti

    2016-06-01

    Full Text Available The search for carotenoids in nature has been extensively studied because of their applications in foods. One treasure of the biopigment source is symbiotic-microorganisms with marine biota. The advantages of symbiont bacteria are easy to culture and sensitize pigments. The use of symbiont bacteria helps to conserve fish, coral reefs, seagrass, and seaweed. Therefore, the bacteria keeps their existence in their ecosystems. In this study, bacterial symbionts were successfully isolated from brown algae Padina sp. The bacterial symbionts had yellow pigment associated with carotenoids. The pigments were characterized using High Performance Liquid Chromatography (HPLC with a Photo Diode Array (PDA detector. The carotenoid pigments in the bacterial symbionts were identified as dinoxanthin, lutein and neoxanthin. Molecular identification by using a 16S rRNA gene sequence method, reveals that the bacterial symbionts were closely related to Bacillus marisflavi with a homology of 99%. Keywords :carotenoid pigments, brown algae, Padina, bacterial symbionts, 16S rRNA

  16. Hydrodynamic bearings

    CERN Document Server

    Bonneau, Dominique; Souchet, Dominique

    2014-01-01

    This Series provides the necessary elements to the development and validation of numerical prediction models for hydrodynamic bearings. This book describes the rheological models and the equations of lubrication. It also presents the numerical approaches used to solve the above equations by finite differences, finite volumes and finite elements methods.

  17. Benthic foraminifera of the Panamanian Province: distribution and origins.

    Science.gov (United States)

    Crouch, R.W.; Poag, C.W.

    1987-01-01

    Two hundred twenty-nine species of benthic foraminifera have been identified from 96 stations representing 33 localities on the eastern Pacific inner continental shelf, ranging from southern Peru to northern Baja California. Their distributions mark nearshore provincial boundaries that are nearly identical with those previously documented from the distribution of ostracodes and molluscs. Thirteen species are characteristic of the Panamanian Province, one is characteristic of the Chilean-Peruvian Province, and one is characteristic of the newly proposed Sonoran Subprovince. Seventeen species (7%) appear to be endemic to the eastern Pacific. Fifty-eight (25%) of the species recognized are disjunct from population centers in the western Pacific, 134 species (59%) are disjunct from modern assemblages of the Atlanto-Carribean region, and 40 species (17%) are disjunct from both the western Pacific and the Atlanto-Caribbean. The distribution of the remaining 57 species (25%) is poorly documented; we classify them as of unknown origin. -Authors

  18. Planktic foraminifera form their shells via metastable carbonate phases.

    Science.gov (United States)

    Jacob, D E; Wirth, R; Agbaje, O B A; Branson, O; Eggins, S M

    2017-11-02

    The calcium carbonate shells of planktic foraminifera provide our most valuable geochemical archive of ocean surface conditions and climate spanning the last 100 million years, and play an important role in the ocean carbon cycle. These shells are preserved in marine sediments as calcite, the stable polymorph of calcium carbonate. Here, we show that shells of living planktic foraminifers Orbulina universa and Neogloboquadrina dutertrei originally form from the unstable calcium carbonate polymorph vaterite, implying a non-classical crystallisation pathway involving metastable phases that transform ultimately to calcite. The current understanding of how planktic foraminifer shells record climate, and how they will fare in a future high-CO 2 world is underpinned by analogy to the precipitation and dissolution of inorganic calcite. Our findings require a re-evaluation of this paradigm to consider the formation and transformation of metastable phases, which could exert an influence on the geochemistry and solubility of the biomineral calcite.

  19. Relationship between benthic foraminifera and sediment in the estuarine complex of Goa

    Digital Repository Service at National Institute of Oceanography (India)

    Dalal, S.G.

    Two indices of community association were used to elucidate the relationship between changes in species composition of benthic foraminifera and changes in the grain size composition of the sediment in estuarine complex of Goa. The degree...

  20. Benthic foraminifera show some resilience to ocean acidification in the northern Gulf of California, Mexico.

    Science.gov (United States)

    Pettit, L R; Hart, M B; Medina-Sánchez, A N; Smart, C W; Rodolfo-Metalpa, R; Hall-Spencer, J M; Prol-Ledesma, R M

    2013-08-30

    Extensive CO2 vents have been discovered in the Wagner Basin, northern Gulf of California, where they create large areas with lowered seawater pH. Such areas are suitable for investigations of long-term biological effects of ocean acidification and effects of CO2 leakage from subsea carbon capture storage. Here, we show responses of benthic foraminifera to seawater pH gradients at 74-207m water depth. Living (rose Bengal stained) benthic foraminifera included Nonionella basispinata, Epistominella bradyana and Bulimina marginata. Studies on foraminifera at CO2 vents in the Mediterranean and off Papua New Guinea have shown dramatic long-term effects of acidified seawater. We found living calcareous benthic foraminifera in low pH conditions in the northern Gulf of California, although there was an impoverished species assemblage and evidence of post-mortem test dissolution. Copyright © 2013 Elsevier Ltd. All rights reserved.

  1. An experimental mesocosm study of microhabitat preferences and mobility in benthic foraminifera: Preliminary results.

    NARCIS (Netherlands)

    Ernst, S.R.; Duijnstee, Ivo; Jannink, N.T.; van der Zwaan, Bert

    2001-01-01

    Three small microcosm experiments were carried out to study the microhabitat preferences and mobility of benthic foraminifera from the northern Adriatic Sea. Following initial homogenization, the foraminiferal assemblages developed a clear microhabitat partitioning in the microcosms within 20 days.

  2. Secondary calcification of planktic foraminifera from the Indian sector of Southern ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Mohan, R.; Shetye, S.; Tiwari, M.; AnilKumar, N.

    This study focused on planktic foraminifera in plankton tows and surface sediments from the western Indian sector of Southern Ocean in order to evaluate the potential foraminiferal secondary calcification and/or dissolution in the sediment...

  3. Sediment traps as a new tool for estimation of longevity of planktonic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.

    Sediment trap technique provides time series data of sinking particles (faunal and sediment) from surface to bottom of the sea. Besides many other applications, data can also be used to estimate life span of planktonic foraminifera. Based on rearing...

  4. Does carbonate ion control planktonic foraminifera shell calcification in upwelling regions?

    Digital Repository Service at National Institute of Oceanography (India)

    Naik, S.S.; Godad, S.P.; Naidu, P.D.

    Planktonic foraminifera shell weights have been recognized as possible proxy for surface water carbonate ion concentration [CO sup(=) sub(3)] and atmospheric CO sub(2). However, to utilize this proxy, it is important to understand whether shell...

  5. Proloculus size variation in Recent benthic foraminifera: Implications for paleoclimatic studies

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Rao, A.S.

    Ratios of dimorphic (microspheric/megalospheric) forms of Foraminifera are affected by temperature and hence are useful in paleoclimatic studies. In some cases, however, it is not possible to distinguish between the dimorphic forms and, therefore...

  6. Distribution of foraminifera in the lagoons of certain Islands of the Lakshadweep Archipelago, Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Sivadas, P.; Narayanan, B.; Jayalakshmy, K.V.; Kutty, M.K.

    A total of 107 foraminiferal species belonging to 29 families and 48 genera have been identified from the lagoonal sediments of Agatti, Kavaratti, Suhelipar, and Minicoy atolls of Lakshadweep. The fauna is dominated by calcareous Foraminifera...

  7. Oxygen isotopic analyses of individual planktic foraminifera species: Implications for seasonality in the western Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Niitsuma, N.; Naik, S.S.

    The variation of stable isotopes between individual shells of planktic foraminifera of a given species and size may provide short-term seasonal insight on Paleoceanography. In this context, oxygen isotope analyses of individual Globigerinoides...

  8. Planktonic foraminifera from a quaternary deep sea core from the southern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Naidu, P.D.; Rao, P.S.; Pattan, J.N.

    An investigation on planktonic foraminifera and calcium carbonate content of a box core collected at a depth of 2556 m from the southern part of the Arabian sea indicates faunal changes depicting Quaternary climatic fluctuations. Based on the study...

  9. Response of foraminifera to a reverse osmosis briny discharge

    Science.gov (United States)

    Small, Richard Eustace Aiken

    Reverse osmosis water treatment plants are becoming the preferred means of generating potable water for many eastern North Carolina communities. At these facilities, reject brine solutions---sometimes containing up to 10 times the initial concentration of dissolved solids---are created and often discharged into estuarine waters. Several state and federal agencies have expressed concern over the potential ecological impacts this wastewater could have on these sensitive environments. Monitoring of a brine discharge site in Currituck County, North Carolina revealed significantly higher conductivity values within ~50 m of the point source. One group of organisms that have proven useful in other studies for monitoring impact of anthropogenic pollution in estuaries is Foraminifera. Foraminifera are abundant microorganisms that are widespread in most marginal-marine and marine environments; nevertheless, individual taxa are highly selective of their habitat. Nearly all species build shells (tests) that are preserved in coastal sediments, allowing for reconstruction of previous marine conditions. Species abundance data was collected from surface and sub-surface samples taken in the area surrounding the brine point source. Two taxa (Ammobaculites spp. and Ammotium sp.) accounted for 98.5% of all normalized specimens. Abundance is significantly less in the sub-surface samples (Student's t-test, p<0.0001), likely due to taphonomic effects. Abundance does not appear correlated with discharge of the wastewater; instead, natural parameters appear to affect abundance in an assemblage to a greater degree. Species distribution is similar in surface and sub-surface samples. Foraminiferal diversity is significantly less near the discharge based on one sample collected within 5 m of the discharge site; samples at greater distances do not appear affected. Loss of diversity within a few meters of the discharge site is consistent with previous studies, but more data would be needed to

  10. 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

  11. Functional equivalence and evolutionary convergence in complex communities of microbial sponge symbionts.

    Science.gov (United States)

    Fan, Lu; Reynolds, David; Liu, Michael; Stark, Manuel; Kjelleberg, Staffan; Webster, Nicole S; Thomas, Torsten

    2012-07-03

    Microorganisms often form symbiotic relationships with eukaryotes, and the complexity of these relationships can range from those with one single dominant symbiont to associations with hundreds of symbiont species. Microbial symbionts occupying equivalent niches in different eukaryotic hosts may share functional aspects, and convergent genome evolution has been reported for simple symbiont systems in insects. However, for complex symbiont communities, it is largely unknown how prevalent functional equivalence is and whether equivalent functions are conducted by evolutionarily convergent mechanisms. Sponges represent an evolutionarily divergent group of species with common physiological and ecological traits. They also host complex communities of microbial symbionts and thus are the ideal model to test whether functional equivalence and evolutionary convergence exist in complex symbiont communities across phylogenetically divergent hosts. Here we use a sampling design to determine the phylogenetic and functional profiles of microbial communities associated with six sponge species. We identify common functions in the six microbiomes, demonstrating the existence of functional equivalence. These core functions are consistent with our current understanding of the biological and ecological roles of sponge-associated microorganisms and also provide insight into symbiont functions. Importantly, core functions also are provided in each sponge species by analogous enzymes and biosynthetic pathways. Moreover, the abundance of elements involved in horizontal gene transfer suggests their key roles in the genomic evolution of symbionts. Our data thus demonstrate evolutionary convergence in complex symbiont communities and reveal the details and mechanisms that underpin the process.

  12. Relationship between abundance and morphology of benthic foraminifera Epistominella exigua: Palaeoclimatic implications

    Digital Repository Service at National Institute of Oceanography (India)

    Saraswat, R.; Deopujari, A.; Nigam, R.; Henriques, P.J.

    foraminiferal species vary with ambient conditions and are used as paleoclimatic proxy (Thiede, 1971; Prell, 1984; Nigam and Rao, 1987; 1989; Anderson and Prell, 1993; Nigam and Khare, 1999; Peeters et al., 2002; Žarić et al., 2005; Saraswat et al., 2005a...; 2005b). The abundance and morphology of benthic foraminifera is closely associated with the reproduction which depends on the ambient environmental conditions. Therefore, the changes in abundance and morphology of the benthic foraminifera should...

  13. Pre-monsoon living planktonic foraminifera from the Southeastern Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.; Naidu, P.D.; Muralinath, A.S.

    with hexamethylene tetramine. ! In the laboratory, all the planktonic foraminiferal specimens > 200 microns were separated by hand picking for identification and estimation of their relative abundance. . The area of investigation (Fig. lA) is influenced by both... and distribution of Planktonic foraminifera (No, of specimens x 1000). RESULTS AND DISCUSSION A total of 28 species of planktonic foraminifera were encountered in this investigation representing the planktonic foraminiferal assemblage during the month of May 1985...

  14. Bearing structures

    International Nuclear Information System (INIS)

    Lee, A.S.; Preece, G.E.

    1988-01-01

    A hydrostatic bearing for the lower end of the vertical shaft of a sodium pump comprises a support shell encircling the shaft and a bush located between the shell and shaft. Liquid sodium is fed from the pump outlet to the bush/shaft and bush/shell interfaces to provide hydrostatic support. The bush outer surface and the shell inner surface are of complementary part-spherical shape and the bush floats relative to the shaft so that the bush can align itself with the shaft axis. Monitoring of the relative rotational speed of the bush with respect to the shaft (such rotation being induced by the viscous drag forces present) is also performed for the purposes of detecting abnormal operation of the bearing or partial seizure, at least one magnet is rotatable with the bush, and a magnetic sensor provides an output having a frequency related to the speed of the bush. (author)

  15. Camshaft bearing arrangement

    Energy Technology Data Exchange (ETDEWEB)

    Aoi, K.; Ozawa, T.

    1986-06-10

    A bearing arrangement is described for the camshaft of an internal combustion engine or the like which camshaft is formed along its length in axial order with a first bearing surface, a first cam lobe, a second bearing surface, a second cam lobe, a third bearing surface, a third cam lobe and a fourth bearing surface, the improvement comprising first bearing means extending around substantially the full circumference of the first bearing surface and journaling the first bearing surface, second bearing means extending around substantially less than the circumference of the second bearing surface and journaling the second bearing surface, third bearing means extending around substantially less than the circumference of the third bearing surface and journaling the third bearing surface, and fourth bearing means extending around substantially the full circumference of the fourth bearing surface and journaling the first bearing surface.

  16. Planktonic foraminifera in the Arctic: potentials and issues regarding modern and quaternary populations

    Energy Technology Data Exchange (ETDEWEB)

    Eynaud, Frederique, E-mail: f.eynaud@epoc.u-bordeaux1.fr [Universite Bordeaux I, Laboratoire EPOC (Environnements et Paleoenvironnements OCeaniques), UMR CNRS 5805, Avenue des facultes, 33405 Talence cedex - France (France)

    2011-05-15

    Calcareous microfossils are widely used by paleoceanographers to investigate past sea-surface hydrology. Among these microfossils, planktonic foraminifera are probably the most extensively used tool (e.g. [1] for a review), as they are easy to extract from the sediment and can also be used for coupled geochemical (e.g; {delta}{sup 18}O, {delta}{sup 13}C, Mg/Ca) and paleo-ecological investigations. Planktonic foraminifera are marine protists, which build a calcareous shell made of several chambers which reflect in their chemistry the properties of the ambient water-masses. Planktonic foraminifera are known to thrive in various habitats, distributed not only along a latitudinal gradient, but also along different water-depth intervals within surface waters (0-1000 m). Regarding their biogeographical distribution, planktonic foraminifera assemblages therefore mirror different water-masses properties, such as temperature, salinity and nutrient content of the surface water in which they live. The investigation of the specific composition of a fossil assemblage (relative abundances) is therefore a way to empirically obtain (paleo)information on past variations of sea-surface hydrological parameters. This paper focuses on the planktonic foraminifera record from the Arctic domain. This polar region records peculiar sea-surface conditions, with the influence of nearly perennial sea-ice cover development. This has strong impact on living foraminifera populations and on the preservation of their shells in the underlying sediments.

  17. Recent benthic foraminifera from the Caribbean continental slope and shelf off west of Colombia

    Science.gov (United States)

    Fiorini, Flavia

    2015-07-01

    A quantitative benthic foraminiferal analysis was conducted on 30 sea-floor sediment samples distributed along the continental slope and shelf in Fuerte Area (Colombian Caribbean), between 39 and 2469 m water depth. The aims of the research were to provide data on the distribution of southwestern Caribbean Recent benthic foraminifera, to estimate changes in the foraminiferal distribution related to the bathymetry and the characteristics of the substrate, to define a data-bank on distribution of recent tropical benthic foraminifera from the southwestern Caribbean, to provide reference on foraminiferal distribution that can be used in bathymetric reconstructions of ancient environments. Three different assemblages corresponding to three different environments were identified by cluster analysis. Assemblage A, characterized by variable percentages of porcellaneous, hyaline and agglutinated benthic foraminifera indicative of shelf environments. Assemblage B, dominated by calcareous hyaline foraminifera mainly composed of infaunal foraminifera corresponding to upper bathyal, marine conditions. Assemblage C, composed by agglutinated and calcareous hyaline foraminifera characteristic of normal deep-water marine environments.

  18. Symbiont acquisition as neoseme: origin of species and higher taxa

    Science.gov (United States)

    Bermudes, D.; Margulis, L.

    1987-01-01

    We examine the hypothesis that, in the origin of species and higher taxa of eukaryotes, symbiont acquisition followed by partner integration has been equivalent to neoseme appearance leading to speciation. The formation of stable symbiotic associations involves partner-surface recognition, behavioral and metabolic interaction, and, in some cases, gene product (RNA, protein) and genic (RNA, DNA) integration. This analysis is applied here to examples of neosemes that define specific taxa and to neosemes in plants, fungi, and animals that involve the appearance of new types of tissue. If this hypothesis is correct--if the origin of major genetic variation leading to speciation and even higher taxa may occur through symbiont acquisition and integration--then the analysis of "origins of species and higher taxa" becomes analogous to the study of microbial community ecology.

  19. Comparative Genomic Analysis of Holospora spp., Intranuclear Symbionts of Paramecia

    Directory of Open Access Journals (Sweden)

    Sofya K. Garushyants

    2018-04-01

    Full Text Available While most endosymbiotic bacteria are transmitted only vertically, Holospora spp., an alphaproteobacterium from the Rickettsiales order, can desert its host and invade a new one. All bacteria from the genus Holospora are intranuclear symbionts of ciliates Paramecium spp. with strict species and nuclear specificity. Comparative metabolic reconstruction based on the newly sequenced genome of Holospora curviuscula, a macronuclear symbiont of Paramecium bursaria, and known genomes of other Holospora species shows that even though all Holospora spp. can persist outside the host, they cannot synthesize most of the essential small molecules, such as amino acids, and lack some central energy metabolic pathways, including glycolysis and the citric acid cycle. As the main energy source, Holospora spp. likely rely on nucleotides pirated from the host. Holospora-specific genes absent from other Rickettsiales are possibly involved in the lifestyle switch from the infectious to the reproductive form and in cell invasion.

  20. 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. © 2012 The Author(s) Journal of Eukaryotic Microbiology © 2012 International Society of Protistologists.

  1. 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

  2. Phylogenetic affinity of arbuscular mycorrhizal symbionts in Psilotum nudum.

    Science.gov (United States)

    Winther, Jennifer L; Friedman, William E

    2009-09-01

    Many lineages of land plants (from lycopsids to angiosperms) have non-photosynthetic life cycle phases that involve obligate mycoheterotrophic arbuscular mycorrhizal (AM) associations where the plant host gains organic carbon through glomalean symbionts. Our goal was to isolate and phylogenetically identify the AM fungi associated with both the autotrophic and underground mycoheterotrophic life cycle phases of Psilotum nudum. Phylogenetic analyses recovered 11 fungal phylotypes in four diverse clades of Glomus A that form AM associations with P. nudum mycoheterotrophic gametophytes and autotrophic sporophytes, and angiosperm roots found in the same greenhouse pots. The correspondence of identities of AM symbionts in P. nudum sporophytes, gametophytes and neighboring angiosperms provides compelling evidence that photosynthetic heterospecific and conspecific plants can serve as the ultimate sources of fixed carbon for mycoheterotrophic gametophytes of P. nudum, and that the transfer of carbon occurs via shared fungal networks. Moreover, broader phylogenetic analyses suggest greenhouse Psilotum populations, like field-surveyed populations of mycoheterotrophic plants, form AM associations with restricted clades of Glomus A. The phylogenetic affinities and distribution of Glomus A symbionts indicate that P. nudum greenhouse populations have the potential to be exploited as an experimental system to further study the physiology, ecology and evolution of mycoheterotrophic AM associations.

  3. 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. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  4. On the accumulation of radionuclids by lichen symbionts

    International Nuclear Information System (INIS)

    Nifontova, M.G.; Kulikov, N.V.

    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 ( 90 Sr and 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-seaweek 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 137 Cs sorption by seaweeds and tells on the total content of radiocesium in plant thallus

  5. 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.

  6. Cellular tropism, population dynamics, host range and taxonomic status of an aphid secondary symbiont, SMLS (Sitobion miscanthi L type symbiont.

    Directory of Open Access Journals (Sweden)

    Tong Li

    Full Text Available SMLS (Sitobion miscanthi L type symbiont is a newly reported aphid secondary symbiont. Phylogenetic evidence from molecular markers indicates that SMLS belongs to the Rickettsiaceae and has a sibling relationship with Orientia tsutsugamushi. A comparative analysis of coxA nucleotide sequences further supports recognition of SMLS as a new genus in the Rickettsiaceae. In situ hybridization reveals that SMLS is housed in both sheath cells and secondary bacteriocytes and it is also detected in aphid hemolymph. The population dynamics of SMLS differ from those of Buchnera aphidicola and titer levels of SMLS increase in older aphids. A survey of 13 other aphids reveals that SMLS only occurs in wheat-associated species.

  7. Cellular Tropism, Population Dynamics, Host Range and Taxonomic Status of an Aphid Secondary Symbiont, SMLS (Sitobion miscanthi L Type Symbiont)

    Science.gov (United States)

    Li, Tong; Xiao, Jin-Hua; Xu, Zhao-Huan; Murphy, Robert W.; Huang, Da-Wei

    2011-01-01

    SMLS (Sitobion miscanthi L type symbiont) is a newly reported aphid secondary symbiont. Phylogenetic evidence from molecular markers indicates that SMLS belongs to the Rickettsiaceae and has a sibling relationship with Orientia tsutsugamushi. A comparative analysis of coxA nucleotide sequences further supports recognition of SMLS as a new genus in the Rickettsiaceae. In situ hybridization reveals that SMLS is housed in both sheath cells and secondary bacteriocytes and it is also detected in aphid hemolymph. The population dynamics of SMLS differ from those of Buchnera aphidicola and titer levels of SMLS increase in older aphids. A survey of 13 other aphids reveals that SMLS only occurs in wheat-associated species. PMID:21789197

  8. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles

    OpenAIRE

    Kovacs, Jennifer L.; Wolf, Candice; Voisin, Den?; Wolf, Seth

    2017-01-01

    Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness e...

  9. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles.

    Directory of Open Access Journals (Sweden)

    Jennifer L Kovacs

    Full Text Available Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness effects for the larvae of two species of aphidophagous lady beetles that consumed aphids with facultative symbionts. In both species, larvae that consumed aphids with secondary symbionts were significantly less likely to survive to adulthood. In this study we tested whether adult Harmonia axyridis and Hippodamia convergens lady beetles avoided aphids with symbionts in a series of choice experiments. Adults of both lady beetle species were as likely to choose aphids with symbionts as those without, despite the potential negative fitness effects associated with consuming aphids with facultative symbionts. This may suggest that under natural conditions aphid secondary symbionts are not a significant source of selection for predatory lady beetles.

  10. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles

    Science.gov (United States)

    Wolf, Candice; Voisin, Dené; Wolf, Seth

    2017-01-01

    Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness effects for the larvae of two species of aphidophagous lady beetles that consumed aphids with facultative symbionts. In both species, larvae that consumed aphids with secondary symbionts were significantly less likely to survive to adulthood. In this study we tested whether adult Harmonia axyridis and Hippodamia convergens lady beetles avoided aphids with symbionts in a series of choice experiments. Adults of both lady beetle species were as likely to choose aphids with symbionts as those without, despite the potential negative fitness effects associated with consuming aphids with facultative symbionts. This may suggest that under natural conditions aphid secondary symbionts are not a significant source of selection for predatory lady beetles. PMID:28880922

  11. 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...... and the original symbiont, and by the ant species the novel symbiont came from. The colony founding stage may thus provide an efficient but transient window for horizontal transmission, in which the fungus is unable to actively defend its partnership position before the host feeds on it, so that host fecal...

  12. Aphid secondary symbionts do not affect prey attractiveness to two species of predatory lady beetles.

    Science.gov (United States)

    Kovacs, Jennifer L; Wolf, Candice; Voisin, Dené; Wolf, Seth

    2017-01-01

    Heritable symbionts have been found to mediate interactions between host species and their natural enemies in a variety of organisms. Aphids, their facultative symbionts, and their potential fitness effects have been particularly well-studied. For example, the aphid facultative symbiont Regiella can protect its host from infection from a fungal pathogen, and aphids with Hamiltonella are less likely to be parasitized by parasitic wasps. Recent work has also found there to be negative fitness effects for the larvae of two species of aphidophagous lady beetles that consumed aphids with facultative symbionts. In both species, larvae that consumed aphids with secondary symbionts were significantly less likely to survive to adulthood. In this study we tested whether adult Harmonia axyridis and Hippodamia convergens lady beetles avoided aphids with symbionts in a series of choice experiments. Adults of both lady beetle species were as likely to choose aphids with symbionts as those without, despite the potential negative fitness effects associated with consuming aphids with facultative symbionts. This may suggest that under natural conditions aphid secondary symbionts are not a significant source of selection for predatory lady beetles.

  13. Biparental transmission of Verminephrobacter symbionts in the earthworm Aporrectodea tuberculata (Lumbricidae).

    Science.gov (United States)

    Paz, Laura-Carlota; Schramm, Andreas; Lund, Marie Braad

    2017-05-01

    Most lumbricid earthworms harbor species-specific Verminephrobacter symbionts in their excretory organs (nephridia). These symbionts are vertically transmitted via the cocoon, where they colonize the embryos. Despite cospeciation for >100 million years with their hosts, Verminephrobacter lack genome reduction and AT bias typical of evolutionary old, vertically transmitted symbionts, caused by recurring bottlenecks. We hypothesized that biparental symbiont transmission into the cocoon enabled genetic mixing and relieved the bottleneck, and tested biparental transmission experimentally for V. aporrectodeae subsp. tuberculata, the specific symbiont of the earthworm Aporrectodea tuberculata, for which aposymbiotic worm lines are available. Virgin symbiotic and aposymbiotic adult worms were tagged, mated in pairs, separated before the start of cocoon production and their offspring assessed for Verminephrobacter. Specific PCR detected the symbionts in 41.5% of 188 juveniles produced by 20 aposymbiotic worms; fluorescence in situ hybridization showed a patchy but successful colonization of their nephridia. Symbionts were present in the mucus but absent in feed, soil, and spermatophora/nephridia of the aposymbiotic partner, suggesting symbiont transfer via mucus during mating. These results are consistent with the hypothesis that genome evolution in Verminephrobacter is distinct from other vertical-ly transmitted symbionts due to genetic mixing during transmission, partially facilitated by biparental transmission. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  14. A Novel, Extremely Elongated, and Endocellular Bacterial Symbiont Supports Cuticle Formation of a Grain Pest Beetle.

    Science.gov (United States)

    Hirota, Bin; Okude, Genta; Anbutsu, Hisashi; Futahashi, Ryo; Moriyama, Minoru; Meng, Xian-Ying; Nikoh, Naruo; Koga, Ryuichi; Fukatsu, Takema

    2017-09-26

    The saw-toothed grain beetle, Oryzaephilus surinamensis (Silvanidae), is a cosmopolitan stored-product pest. Early studies on O. surinamensis in the 1930s described the presence of peculiar bacteriomes harboring endosymbiotic bacteria in the abdomen. Since then, however, the microbiological nature of the symbiont has been elusive. Here we investigated the endosymbiotic system of O. surinamensis in detail. In the abdomen of adults, pupae, and larvae, four oval bacteriomes were consistently identified, whose cytoplasm was full of extremely elongated tubular bacterial cells several micrometers wide and several hundred micrometers long. Molecular phylogenetic analysis identified the symbiont as a member of the Bacteroidetes , in which the symbiont was the most closely related to the endosymbiont of a grain pest beetle, Rhyzopertha dominica (Bostrichidae). The symbiont was detected in developing embryos, corroborating vertical symbiont transmission through host generations. The symbiont gene showed AT-biased nucleotide composition and accelerated molecular evolution, plausibly reflecting degenerative evolution of the symbiont genome. When the symbiont infection was experimentally removed, the aposymbiotic insects grew and reproduced normally, but exhibited a slightly but significantly more reddish cuticle and lighter body mass. These results indicate that the symbiont of O. surinamensis is not essential for the host's growth and reproduction but contributes to the host's cuticle formation. Symbiont genome sequencing and detailed comparison of fitness parameters between symbiotic and aposymbiotic insects under various environmental conditions will provide further insights into the symbiont's biological roles for the stored-product pest. IMPORTANCE Some beetles notorious as stored-product pests possess well-developed symbiotic organs called bacteriomes for harboring specific symbiotic bacteria, although their biological roles have been poorly understood. Here we report

  15. Distribution of benthic foraminifera along the Iranian Coast

    Science.gov (United States)

    Amao, Abduljamiu; Kaminski, Michael

    2017-04-01

    This study focuses on the distribution of benthic foraminifera along the Iranian coast of the Gulf from the northeast close to Shatt Al-Arab/Arvand Rud to the southeast near the Strait of Hormuz where it connects to the Indian Ocean. The Gulf is a naturally stressed environment due to extremes of salinity, temperatures and anthropogenic influences such as rapid urbanization projects, maritime transport, large numbers of desalination plants and oil platforms. These activities over time continue to compound the already stressed environment. Historical records on foraminiferal diversity and distribution in the Gulf commonly underestimate its benthic foraminiferal composition and diversity. Thirty-two samples collected from depths ranging between 20 to 45 m were analyzed for total foraminiferal assemblages. A total of 224 benthic foraminiferal species and subspecies belonging to 63 genera, 34 families, 22 superfamilies and 6 orders were recognized. The assemblages are dominated by hyaline taxa (45.3%) and porcelaneous foraminiferal (35.3%), while agglutinated foraminiferal groups are comprise a lower proportion (19.4%). The ten most abundant genera include Asterorotalia (13.3%), Quinqueloculina (12.4%), Bolivina (9.8%), Nonion (8.6%), Ammonia (5.5%), Textularia (5.4%), Elphidium (5.2%), Cibicides (3.9%), Challengerella (3.6%) and Hanzawaia (3.4%). The most common species are Nonion sp. 1 (5.45%), Asterorotalia dentata (5.03%), Quinqueloculina sp. 1 (4.8%), Nonion sp. 2 (4.5%), Rotalinoides cf. R. gaimardii (3.3%), Asterorotalia sp. 3 (3.2%), Quinqueloculina sp. 8 (3.1%), Bolivina cf. B. persiensis (3.0%), Bolivina cf. B. striatula (2.9%), and Ammonia sp. 1 (2.9%). We speculate that feeding strategy, e.g., herbivore (Nonion, Ammonia, Elphidium and Asterorotalia), the proportion of finer sediments (mud), availability of nutrients and presence of oxygen are factors controlling the diversity and distribution of benthic foraminifera in the Gulf. Due to the importance of

  16. Benthic foraminifera as indicators of pollution in high latitude marine environments

    Science.gov (United States)

    Dijkstra, N.; Junttila, J.; Husum, K.; Carroll, J.; Klitgaard-Kristensen, D.; Hald, M.

    2012-04-01

    An increasing number of studies demonstrate the potential of benthic foraminifera to characterize ecological status. However, the use of benthic foraminifera as bio-indicators has previously not been tested in high latitudes. This research contributes to the development of foraminifera as a bio-monitoring technique for the Arctic region, as industrial activities in this region will increase in the coming years. Surface sediments (0-1 cm) from sites close to gas fields in the SW Barents Sea were studied. In addition, to elucidate the range from less to very affected, surface sediments from the harbor of the town of Hammerfest (70° N) were studied. At least 300 living benthic foraminifera from the size fraction 100 µm-1 mm were counted and identified at species level. Pollution levels (heavy metals and persistent organic pollutants) and sediment properties (grainsize and TOC) were also analyzed. Pollution levels at the sea floor in the SW Barents Sea are of background to good level (level I-II) according to the definitions by the Water Framework Directorate (WFD). Benthic foraminiferal assemblages are influenced by natural environmental parameters such as water mass properties, water depth, nutrient availability, bottom current strength, and grain size. Surface sediments from the Hammerfest harbor are of moderate environmental status (WFD level II-III) based on heavy metal concentrations and of bad environmental status (WFD IV-V) based on persistent organic pollutant concentrations. Opportunistic benthic foraminifera are dominating the assemblages. The most polluted areas in the harbor are barren for foraminifera or have high amounts of deformed shells. In both environments the foraminiferal diversity of the samples, does not correspond to expected environmental status based on the pollution levels of the sediments. Environmental status classes, based on benthic foraminifera instead of macrofauna, would allow rapid analyses of the environmental impact of pollution.

  17. Ecological tolerances of Miocene larger benthic foraminifera from Indonesia

    Science.gov (United States)

    Novak, Vibor; Renema, Willem

    2018-01-01

    To provide a comprehensive palaeoenvironmental reconstruction based on larger benthic foraminifera (LBF), a quantitative analysis of their assemblage composition is needed. Besides microfacies analysis which includes environmental preferences of foraminiferal taxa, statistical analyses should also be employed. Therefore, detrended correspondence analysis and cluster analysis were performed on relative abundance data of identified LBF assemblages deposited in mixed carbonate-siliciclastic (MCS) systems and blue-water (BW) settings. Studied MCS system localities include ten sections from the central part of the Kutai Basin in East Kalimantan, ranging from late Burdigalian to Serravallian age. The BW samples were collected from eleven sections of the Bulu Formation on Central Java, dated as Serravallian. Results from detrended correspondence analysis reveal significant differences between these two environmental settings. Cluster analysis produced five clusters of samples; clusters 1 and 2 comprise dominantly MCS samples, clusters 3 and 4 with dominance of BW samples, and cluster 5 showing a mixed composition with both MCS and BW samples. The results of cluster analysis were afterwards subjected to indicator species analysis resulting in the interpretation that generated three groups among LBF taxa: typical assemblage indicators, regularly occurring taxa and rare taxa. By interpreting the results of detrended correspondence analysis, cluster analysis and indicator species analysis, along with environmental preferences of identified LBF taxa, a palaeoenvironmental model is proposed for the distribution of LBF in Miocene MCS systems and adjacent BW settings of Indonesia.

  18. Oceanographic controls on the diversity and extinction of planktonic foraminifera.

    Science.gov (United States)

    Peters, Shanan E; Kelly, Daniel C; Fraass, Andrew J

    2013-01-17

    Understanding the links between long-term biological evolution, the ocean-atmosphere system and plate tectonics is a central goal of Earth science. Although environmental perturbations of many different kinds are known to have affected long-term biological evolution, particularly during major mass extinction events, the relative importance of physical environmental factors versus biological interactions in governing rates of extinction and origination through geological time remains unknown. Here we use macrostratigraphic data from the Atlantic Ocean basin to show that changes in global species diversity and rates of extinction among planktonic foraminifera have been linked to tectonically and climatically forced changes in ocean circulation and chemistry from the Jurassic period to the present. Transient environmental perturbations, such as those that occurred after the asteroid impact at the end of the Cretaceous period approximately 66 million years ago, and the Eocene/Oligocene greenhouse-icehouse transition approximately 34 million years ago, are superimposed on this general long-term relationship. Rates of species origination, by contrast, are not correlated with corresponding macrostratigraphic quantities, indicating that physiochemical changes in the ocean-atmosphere system affect evolution principally by driving the synchronous extinction of lineages that originated owing to more protracted and complex interactions between biological and environmental factors.

  19. Recent benthic foraminifera assemblages from mangrove swamp and channels of Abu Dhabi (UAE)

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.; Odeh, Weaam A. S. Al; Paul, Andreas; Song, Jianfeng; Freeman, Mark; Michel, Françoise

    2017-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Persian/Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations from mangrove swamps and channels located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of benthic foraminifera in different sedimentary facies in the mangal and in the surrounding natural environments of the upper and lower intertidal area (mud flats and channels). A 100 m transect across a natural channel in a mangal on the eastern side of Abu Dhabi Island was sampled in detail for sedimentological and foraminiferal analysis. Forty-seven samples were collected at 2 meter intervals along the transect in a number of different sedimentary facies including; fine sediment in areas exposed during low tide and close to mangrove trees (Avicennia marina), fine sediment rich in leaf material, coarse sediment in channels, and coarse sediments with a shell lag. At each sampling location environmental parameters were recorded, including water depth, salinity, temperature and pH. Samples collected for foraminiferal analysis were stained in rose Bengal in order to identify living specimens. Samples collected on the mud flat at the margin of the channel show a living foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Cribroelphidium, Triloculina, Quinqueloculina, Sigmoilinita, Spiroloculina, Peneroplis and Spirolina. Samples collected in the lower (wet) intertidal area close to Avicennia marina roots, presented a low-diversity assemblage mostly comprising small-sized opportunistic foraminifera of the genera Ammonia and Cribroelphidium along with rare Triloculina and

  20. The Physiology of Microbial Symbionts in Fungus-Farming Termites

    DEFF Research Database (Denmark)

    Rodrigues da Costa, Rafael

    with their symbionts are main decomposer of organic matter in Africa, and this is reflect of a metabolic complementarity to decompose plant biomass in the genome of the three organisms involved in this symbiosis. Many of the physiological aspects of this symbiosis remain obscure, and here I focus on physiology...... termites where this is either absent or minimal, and this indicates evolutionary adaptations to dietary intakes displayed by different termite species. In addition to these two physiological aspects of this tripartite symbiosis, we questioned the physiological mechanisms displayed by Termitomyces...

  1. Dynamic energy budgets in syntrophic symbiotic relationships between heterotrophic hosts and photoautotrophic symbionts.

    NARCIS (Netherlands)

    Muller, E.B.; Kooijman, S.A.L.M.; Edmunds, P.J.; Doyle, F.J.; Nisbet, R.M.

    2009-01-01

    In this paper we develop and investigate a dynamic energy budget (DEB) model describing the syntrophic symbiotic relationship between a heterotrophic host and an internal photoautotrophic symbiont. The model specifies the flows of matter and energy among host, symbiont and environment with minimal

  2. 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

    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...

  3. Metatranscriptomics reveal differences in in situ energy and nitrogen metabolism among hydrothermal vent snail symbionts.

    Science.gov (United States)

    Sanders, J G; Beinart, R A; Stewart, F J; Delong, E F; Girguis, P R

    2013-08-01

    Despite the ubiquity of chemoautotrophic symbioses at hydrothermal vents, our understanding of the influence of environmental chemistry on symbiont metabolism is limited. Transcriptomic analyses are useful for linking physiological poise to environmental conditions, but recovering samples from the deep sea is challenging, as the long recovery times can change expression profiles before preservation. Here, we present a novel, in situ RNA sampling and preservation device, which we used to compare the symbiont metatranscriptomes associated with Alviniconcha, a genus of vent snail, in which specific host-symbiont combinations are predictably distributed across a regional geochemical gradient. Metatranscriptomes of these symbionts reveal key differences in energy and nitrogen metabolism relating to both environmental chemistry (that is, the relative expression of genes) and symbiont phylogeny (that is, the specific pathways employed). Unexpectedly, dramatic differences in expression of transposases and flagellar genes suggest that different symbiont types may also have distinct life histories. These data further our understanding of these symbionts' metabolic capabilities and their expression in situ, and suggest an important role for symbionts in mediating their hosts' interaction with regional-scale differences in geochemistry.

  4. A specific mix of generalists: bacterial symbionts in Mediterranean Ircinia spp.

    Science.gov (United States)

    Erwin, Patrick M; López-Legentil, Susanna; González-Pech, Raúl; Turon, Xavier

    2012-03-01

    Microbial symbionts form abundant and diverse components of marine sponge holobionts, yet the ecological and evolutionary factors that dictate their community structure are unresolved. Here, we characterized the bacterial symbiont communities of three sympatric host species in the genus Ircinia from the NW Mediterranean Sea, using electron microscopy and replicated 16S rRNA gene sequence clone libraries. All Ircinia host species harbored abundant and phylogenetically diverse symbiont consortia, comprised primarily of sequences related to other sponge-derived microorganisms. Community-level analyses of bacterial symbionts revealed host species-specific genetic differentiation and structuring of Ircinia-associated microbiota. Phylogenetic analyses of host sponges showed a close evolutionary relationship between Ircinia fasciculata and Ircinia variabilis, the two host species exhibiting more similar symbiont communities. In addition, several bacterial operational taxonomic units were shared between I. variabilis and Ircinia oros, the two host species inhabiting semi-sciophilous communities in more cryptic benthic habitats, and absent in I. fasciculata, which occurs in exposed, high-irradiance habitats. The generalist nature of individual symbionts and host-specific structure of entire communities suggest that: (1) a 'specific mix of generalists' framework applies to bacterial symbionts in Ircinia hosts and (2) factors specific to each host species contribute to the distinct symbiont mix observed in Ircinia hosts. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  5. 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

  6. Heat Stress Affects Facultative Symbiont-Mediated Protection from a Parasitoid Wasp.

    Science.gov (United States)

    Heyworth, Eleanor R; Ferrari, Julia

    2016-01-01

    Many insects carry facultative bacterial symbionts, which provide benefits including resistance to natural enemies and abiotic stresses. Little is known about how these beneficial phenotypes are affected when biotic or abiotic threats occur simultaneously. The pea aphid (Acyrthosiphon pisum) can host several well-characterized symbiont species. The symbiont known as X-type can protect against both parasitoid wasps and heat stress. Here, we used three pea aphid genotypes that were naturally infected with X-type and the symbiont Spiroplasma sp. We compared aphids coinfected with these two symbionts with those cured from X-type and infected with only Spiroplasma to investigate the ability of X-type to confer benefits to the host when two threats are experienced simultaneously. Our aim is to explore how robust symbiont protection may be outside a benign laboratory environment. Aphids were subjected to heat shock either before or after attack by parasitoid wasps. Under a benign temperature regime, the aphids carrying X-type tended to be better protected from the parasitoid than those cured. When the aphids experienced a heat shock before being parasitized aphids carrying X-type were more susceptible than those cured. Regardless of infection with the symbiont, the aphids benefitted from being heat shocked after parasitization. The results demonstrate how resistance to parasitoid wasps can be strongly environment-dependent and that a beneficial phenotype conferred by a symbiont under controlled conditions in the laboratory does not necessarily equate to a consistently useful effect in natural populations.

  7. Early diagenetic overprint in Caribbean sediment cores and its effect on the geochemical composition of planktonic foraminifera

    Directory of Open Access Journals (Sweden)

    M. Regenberg

    2007-11-01

    Full Text Available Early diagenetic features are noticed in the vicinity of carbonate platforms. Planktonic foraminifera of two tropical Atlantic deep-sea sediment cores show the strict relation between micro-scale euhydral crystallites of inorganic precipitates, higher oxygen isotope values and Mg/Ca ratios, and lower Sr/Ca ratios than expected for their pelagic environment in the time interval of ~100 000–550 000 calendar years before present. Laser ablation Mg/Ca (Sr/Ca of crystallite-bearing foraminiferal chamber walls revealed 4–6 times elevated (2–3 times depleted ratios, when ablating the diagenetic overgrowth. Crystalline overgrowth in proportion of 10–20% are estimated to cause the observed geochemical alteration. The extent of foraminiferal Mg/Ca alteration, moreover, seems to be controlled by the composition of the bulk sediment, especially the content of high-magnesium calcite. Anomalous ratios of >6 mmol/mol only occur, when high-magnesium calcite has dissolved within the sediment. The older parts (back to ~800 kyrs of the records are characterized by similar trends of Mg/Ca and Sr/Ca. We discuss possible scenarios to accommodate the obtained geochemical information.

  8. Middle Miocene benthic foraminifera from the Al Khums area, northwestern Libya

    Science.gov (United States)

    El Baz, Sherif M.; Al Furjany, Ahmed

    2018-02-01

    The present study deals with the benthic foraminifera from three sections cropping out in the Al Khums area, northwestern Libya. Lithostratigraphically, these outcrops belong to the Al Khums Formation, which is locally subdivided into two informal members: An Naggazah and Ras Al Mannubiyah. Detailed investigation of the foraminiferal content led to the recognition of 27 species belonging to 16 genera and 13 families. The absence of index planktonic foraminifera does not enable the recognition of any planktonic biozone within the Al Khums Formation. The presence of the larger benthic foraminifera Borelis melo melo enables the assignment of a Middle Miocene age to this rock unit. The studied sections characterized by the common occurrence of benthic foraminiferal species living in a shallow neritic environment. This conclusion is corroborated by the co-occurrence of large oysters, corals and algae.

  9. Benthic Foraminifera in the Changing Ecosystem of Long Island Sound

    Science.gov (United States)

    Thaler, B.; Thomas, E.; Varekamp, J. C.

    2004-05-01

    Long Island Sound (LIS) is an estuary in a heavily urbanized region; Long Island lies to its South, New York City (NYC) to its West and Connecticut to its North. The Connecticut River contributes >70% of the fresh water influx. LIS has a narrow opening to the West (into East River), but exchange with the ocean occurs dominantly at its eastern end, resulting in an east-west gradient in salinity. An east-west gradient is also present in indicators of anthropogenic contamination in the surface sediments (e.g., trace metals) because western LIS is close to the major source of anthropogenic input (NYC). In addition, bottom currents focus fine-grained, contaminant-loaded sediments there. Since the early 1970's western LIS and parts of central LIS have suffered summer hypoxia, probably as a result of increased algal growth caused by anthropogenic nitrogen input. Benthic foraminifera are eukaryote heterotrophic organisms with a calcareous or agglutinated test. We investigated changes in their populations over time in about 2m-long gravity cores in westernmost (WLIS75GGC1; 73o 40'W, 40o 52'N, 19m waterdepth) and coastal central LIS (B1GGC1; 73o 4'W, 41o 10'N, 8m water depth), to document environmental changes over the last millennium, including the time of European settlement and the industrial revolution and population increase. An age model was derived from metal pollution records and 14C dating. Before European settlement, the low-diversity benthic faunas in core B1GGC1, at a depth within the zone of light penetration, were dominated by Elphidium excavatum, a species feeding on living diatoms. In western LIS (below the zone of light penetration) this species was less abundant and Elphidium incertum and Buccella frigida were common. In both cores, the absolute abundance of benthic foraminifera and the relative abundance of Elphidium excavatum increased in the early 1800's, coinciding with a time of rapid increase in human population around LIS and slightly before an

  10. A Novel, Extremely Elongated, and Endocellular Bacterial Symbiont Supports Cuticle Formation of a Grain Pest Beetle

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    Bin Hirota

    2017-09-01

    Full Text Available The saw-toothed grain beetle, Oryzaephilus surinamensis (Silvanidae, is a cosmopolitan stored-product pest. Early studies on O. surinamensis in the 1930s described the presence of peculiar bacteriomes harboring endosymbiotic bacteria in the abdomen. Since then, however, the microbiological nature of the symbiont has been elusive. Here we investigated the endosymbiotic system of O. surinamensis in detail. In the abdomen of adults, pupae, and larvae, four oval bacteriomes were consistently identified, whose cytoplasm was full of extremely elongated tubular bacterial cells several micrometers wide and several hundred micrometers long. Molecular phylogenetic analysis identified the symbiont as a member of the Bacteroidetes, in which the symbiont was the most closely related to the endosymbiont of a grain pest beetle, Rhyzopertha dominica (Bostrichidae. The symbiont was detected in developing embryos, corroborating vertical symbiont transmission through host generations. The symbiont gene showed AT-biased nucleotide composition and accelerated molecular evolution, plausibly reflecting degenerative evolution of the symbiont genome. When the symbiont infection was experimentally removed, the aposymbiotic insects grew and reproduced normally, but exhibited a slightly but significantly more reddish cuticle and lighter body mass. These results indicate that the symbiont of O. surinamensis is not essential for the host’s growth and reproduction but contributes to the host’s cuticle formation. Symbiont genome sequencing and detailed comparison of fitness parameters between symbiotic and aposymbiotic insects under various environmental conditions will provide further insights into the symbiont’s biological roles for the stored-product pest.

  11. Worldwide populations of the aphid Aphis craccivora are infected with diverse facultative bacterial symbionts.

    Science.gov (United States)

    Brady, Cristina M; Asplen, Mark K; Desneux, Nicolas; Heimpel, George E; Hopper, Keith R; Linnen, Catherine R; Oliver, Kerry M; Wulff, Jason A; White, Jennifer A

    2014-01-01

    Facultative bacterial endosymbionts can play an important role in the evolutionary trajectory of their hosts. Aphids (Hemiptera: Aphididae) are infected with a wide variety of facultative endosymbionts that can confer ecologically relevant traits, which in turn may drive microevolutionary processes in a dynamic selective environment. However, relatively little is known about how symbiont diversity is structured in most aphid species. Here, we investigate facultative symbiont species richness and prevalence among world-wide populations of the cowpea aphid, Aphis craccivora Koch. We surveyed 44 populations of A. craccivora, and detected 11 strains of facultative symbiotic bacteria, representing six genera. There were two significant associations between facultative symbiont and aphid food plant: the symbiont Arsenophonus was found at high prevalence in A. craccivora populations collected from Robinia sp. (locust), whereas the symbiont Hamiltonella was almost exclusively found in A. craccivora populations from Medicago sativa (alfalfa). Aphids collected from these two food plants also had divergent mitochondrial haplotypes, potentially indicating the formation of specialized aphid lineages associated with food plant (host-associated differentiation). The role of facultative symbionts in this process remains to be determined. Overall, observed facultative symbiont prevalence in A. craccivora was lower than that of some other well-studied aphids (e.g., Aphis fabae and Acyrthosiphon pisum), possibly as a consequence of A. craccivora's almost purely parthenogenetic life history. Finally, most (70 %) of the surveyed populations were polymorphic for facultative symbiont infection, indicating that even when symbiont prevalence is relatively low, symbiont-associated phenotypic variation may allow population-level evolutionary responses to local selection.

  12. 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

  13. 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

    2009-01-01

    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 lineages. The symbionts

  14. Passive magnetic bearing configurations

    Science.gov (United States)

    Post, Richard F [Walnut Creek, CA

    2011-01-25

    A journal bearing provides vertical and radial stability to a rotor of a passive magnetic bearing system when the rotor is not rotating and when it is rotating. In the passive magnetic bearing system, the rotor has a vertical axis of rotation. Without the journal bearing, the rotor is vertically and radially unstable when stationary, and is vertically stable and radially unstable when rotating.

  15. Interspecific competition between entomopathogenic nematodes (Steinernema is modified by their bacterial symbionts (Xenorhabdus

    Directory of Open Access Journals (Sweden)

    Pages Sylvie

    2006-09-01

    Full Text Available Abstract Background Symbioses between invertebrates and prokaryotes are biological systems of particular interest in order to study the evolution of mutualism. The symbioses between the entomopathogenic nematodes Steinernema and their bacterial symbiont Xenorhabdus are very tractable model systems. Previous studies demonstrated (i a highly specialized relationship between each strain of nematodes and its naturally associated bacterial strain and (ii that mutualism plays a role in several important life history traits of each partner such as access to insect host resources, dispersal and protection against various biotic and abiotic factors. The goal of the present study was to address the question of the impact of Xenorhabdus symbionts on the progression and outcome of interspecific competition between individuals belonging to different Steinernema species. For this, we monitored experimental interspecific competition between (i two nematode species: S. carpocapsae and S. scapterisci and (ii their respective symbionts: X. nematophila and X. innexi within an experimental insect-host (Galleria mellonella. Three conditions of competition between nematodes were tested: (i infection of insects with aposymbiotic IJs (i.e. without symbiont of both species (ii infection of insects with aposymbiotic IJs of both species in presence of variable proportion of their two Xenorhabdus symbionts and (iii infection of insects with symbiotic IJs (i.e. naturally associated with their symbionts of both species. Results We found that both the progression and the outcome of interspecific competition between entomopathogenic nematodes were influenced by their bacterial symbionts. Thus, the results obtained with aposymbiotic nematodes were totally opposite to those obtained with symbiotic nematodes. Moreover, the experimental introduction of different ratios of Xenorhabdus symbionts in the insect-host during competition between Steinernema modified the proportion of

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

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    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.

  17. 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

  18. Primates, Lice and Bacteria: Speciation and Genome Evolution in the Symbionts of Hominid Lice.

    Science.gov (United States)

    Boyd, Bret M; Allen, Julie M; Nguyen, Nam-Phuong; Vachaspati, Pranjal; Quicksall, Zachary S; Warnow, Tandy; Mugisha, Lawrence; Johnson, Kevin P; Reed, David L

    2017-07-01

    Insects with restricted diets rely on symbiotic bacteria to provide essential metabolites missing in their diet. The blood-sucking lice are obligate, host-specific parasites of mammals and are themselves host to symbiotic bacteria. In human lice, these bacterial symbionts supply the lice with B-vitamins. Here, we sequenced the genomes of symbiotic and heritable bacterial of human, chimpanzee, gorilla, and monkey lice and used phylogenomics to investigate their evolutionary relationships. We find that these symbionts have a phylogenetic history reflecting the louse phylogeny, a finding contrary to previous reports of symbiont replacement. Examination of the highly reduced symbiont genomes (0.53-0.57 Mb) reveals much of the genomes are dedicated to vitamin synthesis. This is unchanged in the smallest symbiont genome and one that appears to have been reorganized. Specifically, symbionts from human lice, chimpanzee lice, and gorilla lice carry a small plasmid that encodes synthesis of vitamin B5, a vitamin critical to the bacteria-louse symbiosis. This plasmid is absent in an old world monkey louse symbiont, where this pathway is on its primary chromosome. This suggests the unique genomic configuration brought about by the plasmid is not essential for symbiosis, but once obtained, it has persisted for up to 25 My. We also find evidence that human, chimpanzee, and gorilla louse endosymbionts have lost a pathway for synthesis of vitamin B1, whereas the monkey louse symbiont has retained this pathway. It is unclear whether these changes are adaptive, but they may point to evolutionary responses of louse symbionts to shifts in primate biology. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

  19. Effect of carbonate ion concentration and irradiance on calcification in planktonic foraminifera

    DEFF Research Database (Denmark)

    Lombard, Fabien; da Rocha, R. E.; Bijma, J.

    2010-01-01

    rates of these two species are projected to be 6 to 13% lower than the present conditions, while the final shell weights are reduced by 20 to 27% for O. universa and by 4 to 6% for G. sacculifer. These results indicate that ocean acidification would impact on calcite production by foraminifera and may...

  20. Living planktonic foraminifera during the late summer monsoon period in the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Guptha, M.V.S.; Mohan, R.; Muralinath, A.S.

    with deepening of the mixed layer, since this species preferentially dwells in nutrient-rich upwelling waters. The population density of planktonic foraminifera ranges between 31 and 185 specimens per 10@u-3@@m@u3@@. The low absolute numbers of planktonic...

  1. Invertebrate shells (mollusca, foraminifera) as pollution indicators, Red Sea Coast, Egypt

    Science.gov (United States)

    Youssef, Mohamed; Madkour, Hashem; Mansour, Abbas; Alharbi, Wedad; El-Taher, Atef

    2017-09-01

    To assess the degree of pollution and its impact on the environment along the Red Sea Coast, the most abundant nine species of recent benthic foraminifera and three species of molluscan shells have been selected for the analysis of Fe, Mn, Zn, Cu, Pb, Ni, Co, and Cd concentrations. The selected foraminiferal species are: Textularia agglutinans, Amphispsorus hemprichii, Sorites marginalis, Peneroplis planatus, Borelis schlumbergeri, Amphistegina lessonii, Ammonia beccarii, Operculina gaimairdi, and Operculinella cumingii. The selected molluscan shells are: Lambis truncata and Strombus tricornis (gastropods) and Tridacana gigas (bivalves). The inorganic material analysis of foraminifera and molluscs from the Quseir and Safaga harbors indicates that foraminifera tests include higher concentrations of heavy metals such as Fe and Mn than molluscan shells. These results are supported by the black tests of porcelaneous foraminifera and reflect iron selectivity. The Cd and Pb concentrations in molluscan shells are high in the El Esh Area because of oil pollution at this site. The Cu, Zn, and Ni concentrations in the studied invertebrates are high at Quseir Harbor and in the El Esh Area because of the strong influence of terrigenous materials that are rich in these metals. The heavy metal contamination is mostly attributed to anthropogenic sources.

  2. The Foraminifera of the Saba Bank Expedition, 1972 (Cicar Cruises 34, 35)

    NARCIS (Netherlands)

    Hofker, J.

    1980-01-01

    INTRODUCTION Bottom samples obtained by means of a Van Veen grab during the 1972 Saba Bank Expedition (CICAR cruises 34 and 35) appeared to comprise many samples with Foraminifera. This material was kindly put at my disposal by Dr. D. van Harten of the Geological Institute of the University of

  3. Paleoecology of benthic foraminifera from the Miocene of the San Jacinto Basin, Colombia

    Science.gov (United States)

    Poveda, John Sebastian; Fiorini, Flavia; Andres Trejos, Raul; Vallejo, Diego Felipe; Pardo, Andres

    2015-04-01

    Quantitative benthic foraminifera analysis was conducted on 34 samples collected from a borehole core (393.72m deep) drilled by Colombian Hydrocarbon Agency (ANH) on 2009 in the San Jacinto basin (Northern Colombia). The aims of the research were to define a taxonomical data-bank of Miocene benthic foraminifera for this region, to use the benthic foraminifera assemblages to interpret the paleoenvironment and to identify paleoenvironmental changes. The bottom of the section was dated between lowest Burdigalian to middle Langhian (20.393-17.721 Ma) based on calcareous nannofossils bioevents: LO Helicosphaera ampliaperta, HCO Sphenolithus belemnos and LCO Sphenolithus heteromorphus. The benthic foraminifera fauna identified in the studied samples is composed for the majority of calcareous hyaline tests and is dominated by infaunal taxas. Species belonging to the genera Uvigerina and Lenticulina are commonly occurring in the studied section together with other species typical of outer-shelf upper-bathyal environment. Cibicidoides spp., abundant in the lower part of the section, abruptly decreases in abundance in the upper part. Species belonging to the opportunistic genera Bulimina and Bolivina are more abundant in the upper part of the section. Variability in the abundance of opportunistic species can be associated with tectonic disturbance on the Sinu-San Jacinto fold belt (NW of Colombia) as a result of collision of the Caribbean plate against NW of South America. The tectonics could lead a perturbation on deep ocean sedimentation and circulation.

  4. THE CORRELATION BETWEEN BENTHIC FORAMINIFERA AND SEDIMENT TYPES OF SOUTH MAKASSAR STRAIT

    Directory of Open Access Journals (Sweden)

    Sheilla Zallesa

    2017-07-01

    Full Text Available South Makassar Strait is located between Kalimantan and Sulawesi Islands that is an important oceanographic pathway connecting between the Pacific and Indian oceans. This area is a part of sedimentary basin that has specific seabed morphology and sediment characteristics, including foraminifera as a component of sediments. The purpose of this study is to determine community structure of benthic foraminifera related to sediment characteristics. This study used 20 top core sediment samples from water depth between 200 and 1500 m. There are identified 38 species of benthic foraminifera and some of them are characterized the study area: Anomalinoides colligerus, Lenticulina suborbicularis, Planulina wuellerstorfi, and Pseudonodosaria discrete. The diversity index is categorized as moderate values (1.0=H'= 3 and the average of evenness values is about 0.79. The dominance values are less than 0.5 indicate that there is no dominant species in the study area. In relation to sediment characteristics, it shows that the high abundance of benthic foraminifera occurs in sediment type of silty sand and sandy silt. Moderate abundance appears in sand following by low abundance in silt and sandy silt sediment types.

  5. Response of benthic foraminifera to phytodetritus in the eastern Arabian Sea under low oxygen conditions

    Science.gov (United States)

    Enge, Annekatrin; Wukovits, Julia; Wanek, Wolfgang; Watzka, Margarete; Witte, Ursula; Hunter, William; Heinz, Petra

    2016-04-01

    At water depths between 100 and 1500 m a permanent Oxygen Minimum Zone (OMZ) impinges on the sea floor in the eastern Arabian Sea, exposing benthic organisms to anoxic to suboxic conditions. The flux of organic matter to the sea floor is relatively high at these depths but displays seasonal variation. Deposition of relatively fresh phytodetrital material (phytoplankton remains) can occur within a short period of time after monsoon periods. Several organism groups including foraminifera are involved to different extent in the processing of phytodetritus in the OMZs of the northern Arabian Sea. A series of in situ feeding experiments were performed to study the short-term processing (metabolic processes under hypoxic stress. Variable levels and ratios of phytodetrital carbon and nitrogen indicate specific nutritional demands and storage of food-derived nitrogen in some foraminifera species under near anoxia where the mean phytodetrital nitrogen content in foraminifera was elevated. In summary, foraminifera dominate the short-term processing of phytodetritus by fauna in the OMZ core but are less important in the lower OMZ boundary region of the Indian margin as a result of biological interactions and changes in the distribution of individual foraminiferal species.

  6. A Record of Rotaloid Foraminifera from the Upper Permian-Lower ...

    African Journals Online (AJOL)

    PRABHAS PANDE

    INTRODUCTION. In the history of organic evolution, the end of Palaeozoic Era was marked by the conspicuous event of mass extinctions. Amongst foraminifera, as many as fourteen families became extinct. (Loeblich and Tappan, 1964) during the Permian Period and many new families evolved in the. Mesozoic. There is a ...

  7. A new model for biomineralization and trace-element signatures of Foraminifera tests

    NARCIS (Netherlands)

    Nehrke, G.; Keul, N.; Langer, G.; de Nooijer, L.J.; Bijma, J.; Meibom, A.

    2013-01-01

    The Mg/Ca ratio of Foraminifera calcium carbonate tests is used as proxy for seawater temperature and widely applied to reconstruct global paleo-climatic changes. However, the mechanisms involved in the carbonate biomineralization process are poorly understood. The current paradigm holds that

  8. Distribution of benthic foraminifera within oxygen minima zone, off central west coast, India

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumder, A.; Henriques, P.J.; Nigam, R.

    and analyzed to study the effect of oxygen minima zone on benthic foraminiferal habitat. Benthic foraminifera were studied upto specific level of identification. However, to get a better picture, and keeping in mind that oxygen minima zone in the Arabian Sea...

  9. Recent foraminifera along west coast of India: Restrospect, perspect and prospect

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.

    An immense quantum of work on foraminifera is being carried out in Indian waters by various research centers and universities. However, a thorough review of the foraminiferal studies from Indian waters is yet to be amde. A critical review will also...

  10. Off to new shores: Modeling the potential distribution and future range expansion of larger foraminifera

    Science.gov (United States)

    Weinmann, A. E.; Rödder, D.; Lötters, S.; Langer, M. R.

    2012-04-01

    The distribution of larger foraminifera is strongly controlled by environmental variables, especially temperature. Most of today's taxa of larger foraminifera are restricted to tropical and subtropical regions (between 30° N and 30° S) and their minimum temperature limits are governed by the 14 to 20° C isotherms. However, during times of extensive global warming (e.g. the Eocene and Miocene), larger foraminifera have been found as far North as 50° N (North America and Central Europe) as well as towards 40° S in New Zealand. It has been stated that larger foraminifera are more tolerant of rising sea surface temperatures than reef-building corals. As such they may play a more prominent role as future reef framework and carbonate producers in a steadily warming ocean. During the last century, sea surface temperatures have been rising significantly due to higher CO2 concentrations in the atmosphere. This trend is expected to continue and climate change scenarios for 2100 suggest a further increase by 1 to 6° C (IPCC Synthesis Report, 2007). We applied Species Distribution Models (SDMs) on several taxa of larger foraminifera in order to evaluate their potential distribution under current climate conditions and to predict range expansions within the next 40 years. The studied taxa include Archaias angulatus, which is regionally distributed within the Caribbean region, Calcarina spp., which occurs in the Indo-Pacific area and the true circumglobal taxon Amphistegina spp. Under present climate, Amphistegina spp. shows the widest distribution range due to its greater temperature tolerance. Both Archaias angulatus and Calcarina spp. display potential distributions that cover currently uninhabitet regions, suggesting that weak dispersal abilities are major reasons for their limited distributions. Under future climate, Archaias angulatus and Calcarina spp. show an increase in habitat suitability within their native occurrence ranges, suggesting that their tolerance for

  11. 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...

  12. 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...

  13. Grandeur Alliances: Symbiont Metabolic Integration and Obligate Arthropod Hematophagy.

    Science.gov (United States)

    Rio, Rita V M; Attardo, Geoffrey M; Weiss, Brian L

    2016-09-01

    Several arthropod taxa live exclusively on vertebrate blood. This food source lacks essential metabolites required for the maintenance of metabolic homeostasis, and as such, these arthropods have formed symbioses with nutrient-supplementing microbes that facilitate their host's 'hematophagous' feeding ecology. Herein we highlight metabolic contributions of bacterial symbionts that reside within tsetse flies, bed bugs, lice, reduviid bugs, and ticks, with specific emphasis on B vitamin and cofactor biosynthesis. Importantly, these arthropods can transmit pathogens of medical and veterinary relevance and/or cause infestations that induce psychological and dermatological distress. Microbial metabolites, and the biochemical pathways that generate them, can serve as specific targets of novel control mechanisms aimed at disrupting the metabolism of hematophagous arthropods, thus combatting pest invasion and vector-borne pathogen transmission. Copyright © 2016 Elsevier Ltd. All rights reserved.

  14. How rhizobial symbionts invade plants: the Sinorhizobium–Medicago model

    Science.gov (United States)

    Jones, Kathryn M.; Kobayashi, Hajime; Davies, Bryan W.; Taga, Michiko E.; Walker, Graham C.

    2009-01-01

    Nitrogen-fixing rhizobial bacteria and leguminous plants have evolved complex signal exchange mechanisms that allow a specific bacterial species to induce its host plant to form invasion structures through which the bacteria can enter the plant root. Once the bacteria have been endocytosed within a host-membrane-bound compartment by root cells, the bacteria differentiate into a new form that can convert atmospheric nitrogen into ammonia. Bacterial differentiation and nitrogen fixation are dependent on the microaerobic environment and other support factors provided by the plant. In return, the plant receives nitrogen from the bacteria, which allows it to grow in the absence of an external nitrogen source. Here, we review recent discoveries about the mutual recognition process that allows the model rhizobial symbiont Sinorhizobium meliloti to invade and differentiate inside its host plant alfalfa (Medicago sativa) and the model host plant barrel medic (Medicago truncatula). PMID:17632573

  15. 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,

  16. Improved gas thrust bearings

    Science.gov (United States)

    Anderson, W. J.; Etsion, I.

    1979-01-01

    Two variations of gas-lubricated thrust bearings extend substantially load-carrying range over existing gas bearings. Dual-Action Gas Thrust Bearing's load-carrying capacity is more than ninety percent greater than that of single-action bearing over range of compressibility numbers. Advantages of Cantilever-mounted Thrust Bearing are greater tolerance to dirt ingestion, good initial lift-off characteristics, and operational capability over wide temperature range.

  17. Effects of heavy metals pollution on benthic foraminifera assemblage: the Gulf of Gabes, Tunisia

    Science.gov (United States)

    Ayadi, Najla; Zghal, Ihsen; Bouzid, Jalel; Abdennaceur Ouali, Jamel

    2014-05-01

    Benthic foraminifera are amongst the most abundant protists found in huge marine and brackish water habitat. During the last few decades, many researches had been focused on using benthic foraminifera as bioindicators of marine pollution caused by industrial, domestic and agricultural waste, oil or heavy metal contamination. The aim of this research is to investigate heavy metals pollution in superficial sediments in two industrial locations at the Gulf of Gabes and to examine the reaction of benthic foraminifera towards metallic concentration. The Gulf of Gabes, located on the eastern coast of Tunisia, is regarded as an extremely vital zone and considered as one of the most important area for fishing in the country. During last years, the coastal area of this region had known an important demographic and industrial development, leading to the presence of uncontrolled discharge. Fifteen superficial sediment samples were collected along the coastline of Skhira and Ghannouch- Gabes. They have been analyzed for Al, Cd, Cr, Cu, Pb, and Zn concentrations as well as for the species composition of benthic foraminifera. Results show three levels of metallic contamination with high concentration of cadmium and zinc. Thirty five benthic foraminifera species were identified. Ammonia parkinsoniana, Ammonia beccarii, Peneroplis planatus, Triloculina trigonula and Adelosina longirostraare are the most abundant and common species. Increasing pollution results in a lower species diversity as well as population density, with the presence of a barren zone, and more frequent abnormal specimens. A complementary statistical analysis (PCA/FA and matrix correlation) shows that heavy metals are resulting from the same anthropogenic source and negative correlation between faunal parameters (density and diversity) and pollutants concentrations.

  18. Chemosynthetic symbionts of marine invertebrate animals are capable of nitrogen fixation

    NARCIS (Netherlands)

    Petersen, J.M.; Kemper, A.; Gruber-Vodicka, H.R.; Cardini, U.; van der Geest, M.; Kleiner, M.; Bulgheresi, S.; Mußmann, M; Herbold, C.W.; Seah, B.K.B.; Antony, C.P.; Liu, D.; Belitz, A.; Weber, M.

    2016-01-01

    Chemosynthetic symbioses are partnerships between invertebrate animals and chemosynthetic bacteria. The latter are theprimary producers, providing most of the organic carbon needed for the animal host’s nutrition. We sequenced genomesof the chemosynthetic symbionts from the lucinid bivalve Loripes

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

    DEFF Research Database (Denmark)

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

    2006-01-01

    Earthworms (Annelida; Lumbricidae) harbour species-specific symbiotic bacteria in their nephridia (excretory organs) where the symbionts densely colonize a specific part of the nephridia called the ampulla [1]. The symbiosis is universal among earthworms, the symbionts form a monophyletic cluster...... 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...... 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...

  20. 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...

  1. 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

    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 Pseudonocardia, and the symbiont is primarily vertically transmitted between generations by colony...... with two non-native strains, elucidating the role of genetic distance on preference between strains and Pseudonocardia origin. Our findings suggest that ants tend to prefer bacteria more closely related to their native bacterium and that genetic similarity is probably more important than whether symbionts...

  2. Symbiont shuffling linked to differential photochemical dynamics of Symbiodinium in three Caribbean reef corals

    Science.gov (United States)

    Cunning, Ross; Silverstein, Rachel N.; Baker, Andrew C.

    2018-03-01

    Dynamic symbioses with functionally diverse dinoflagellate algae in the genus Symbiodinium may allow some reef corals to alter their phenotypes through `symbiont shuffling', or changes in symbiont community composition. In particular, corals may become more bleaching resistant by increasing the relative abundance of thermally tolerant Symbiodinium in clade D after bleaching. Despite the immediate relevance of this phenomenon to corals living in warming oceans—and to interventions aimed at boosting coral resilience—the mechanisms governing how, why, and when symbiont shuffling occurs are still poorly understood. Here, we performed controlled thermal bleaching and recovery experiments on three species of Caribbean corals hosting mixtures of D1a ( S. trenchii) and other symbionts in clades B or C. We show that the degree of symbiont shuffling is related to (1) the duration of stress exposure and (2) the difference in photochemical efficiency ( F v /F m) of co-occurring symbionts under stress (i.e., the `photochemical advantage' of one symbiont over the other). The advantage of D1a under stress was greatest in Montastraea cavernosa, intermediate in Siderastrea siderea, and lowest in Orbicella faveolata and correlated positively with the magnitude of shuffling toward D1a. In holobionts where D1a had less of an advantage over co-occurring symbionts (i.e., only slightly higher F v /F m under stress), a longer stress duration was required to elicit commensurate increases in D1a abundance. In fact, across these three coral species, 92.9% of variation in the degree of symbiont shuffling could be explained by the time-integrated photochemical advantage of D1a under heat stress. Although F v /F m is governed by numerous factors that this study is unable to resolve mechanistically, its strong empirical relationship with symbiont shuffling helps elucidate general features that govern this process in reef corals, which will help refine predictions of coral responses to

  3. 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

  4. 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.

  5. Heavy metals contamination and distribution of benthic foraminifera from the Red Sea coastal area, Jeddah, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Mohamed Youssef

    2015-07-01

    Full Text Available The distribution of benthic foraminifera was studied in two stations in the coastal area, located around Jeddah, Red Sea coast, Saudi Arabia. Thirty-three species belonging to 15 genera, 14 families and three suborders were recorded in twenty samples. Some foraminiferal tests display abnormalities in their coiling, general shape of chambers and apertures. On the other hand, concentrations of Fe, Mn, Zn, Cu, Pb, Ni, Cr, and Cd were measured in the tests of the two most common living species of benthic foraminifera (Sorites marginalis and Peneroplis planatus. Significant spatial differences in the metal concentrations of benthic foraminifera were recorded at the two sites. Benthic foraminifera yielded significantly high concentrations of Fe, Mn, Pb and Cu, which may attribute to anthropogenic activities at the studied coastal areas. The anthropogenic activities have a considerable impact, besides other factors, in the abnormalities of foraminiferal test.

  6. The isotopic signature of planktonic foraminifera from the NE Atlantic surface sediments: implications for the reconstruction of past oceanic conditions.

    NARCIS (Netherlands)

    Ganssen, G.M.; Kroon, D.

    2000-01-01

    The stable isotope compositions of the planktonic foraminifera Globigerina bulloides, Globigerinoides ruber (white and pink varieties), Globigerinoides trilobus, Globorotalia inflata and Globorotalia truncatulinoides (right- and left-coiling types) were examined as recorders of North Atlantic

  7. Effect of temperature and salinity on stable isotopic composition of shallow water benthic foraminifera: A laboratory culture study

    Digital Repository Service at National Institute of Oceanography (India)

    Kurtarkar, S.R.; Linshy, V.N.; Saraswat, R.; Nigam, R.

    Quantitative estimation of past climatic parameters from stable isotopic composition of foraminifera relies on estimating the precise relationship between stable isotopic composition of the species analyzed and the physico-chemical factors...

  8. Distribution of planktonic foraminifera in waters of the submarine coral banks in southeast Arabian Sea during winter

    Digital Repository Service at National Institute of Oceanography (India)

    Rao, K.K.; Jayalakshmy, K.V.; Balasubramanian, T.

    Twentyfive species of planktonic foraminifera are recorded from 36 plankton tows collected from waters of the submerged coral banks- Bassas de Pedro, Sesostris and Cora Divh-located at northern end of the Laccadive group of islands in southeastern...

  9. Exploration, Isolation, and Identification of Carotenoid from Bacterial Symbiont of Sponge Callyspongia vaginalis

    Directory of Open Access Journals (Sweden)

    Iqna Kamila Abfa

    2017-06-01

    Full Text Available During the past two decades research on marine bacteria has highlighted the tremendous potential of symbiotic-microorganisms as a source of bioactive secondary. One of the potential of the bacterial symbionts is producing a natural pigment, and these organisms can be used as a sustainable source of natural pigments. Carotenoid is one of the most important pigments that has important roles in physiological and molecular processes of microorganisms, as well as for human health. The objective of this study is to analyze carotenoid pigments from marine bacterial symbionts from sponge and to identify bacterial symbionts that produce carotenoid pigments. Pigment analysis was performed by a UV-VIS spectrophotometer and High Performance Liquid Chromatography (HPLC. Molecular bacterial identification was performed based on 16S rDNA sequence. The isolation of bacterial symbionts from C. vaginalison Zobell 2216E medium resulted in one bacterium, CB-SP5, positively synthesized carotenoids. By reverse phase HPLC analysis, the carotenoid pigments in the bacterial symbionts were identified as diadinoxanthin, fucoxanthin, neoxanthin, dinoxanthin, anddiadinochrome. CB-SP5 shared the highest level of 16S rDNA gene sequence similarity with Psychrobacter celer (99%.   Keywords : carotenoid, sponge, bacterial symbiont, 16S rDNA.

  10. REKONSTRUKSI BATIMETRI DAN IKLIM PURBA BERDASARKAN FORAMINIFERA DAERAH RALLA BARRU, SULAWESI SELATAN INDONESIA

    Directory of Open Access Journals (Sweden)

    Meutia Farida

    2017-10-01

    Full Text Available Daerah Ralla terletak di Kabupaten Barru Provinsi Sulawesi Selatan, tersusun atas batuan karbonat dan vulkanik. Salah satu komponen utama penyusun batuan ini adalah kandungan fosil foraminifera baik planktonik maupun bentonik yang jumlahnya melimpah. Penentuan umur dan lingkungan pengendapan purba (paleobathymetry, menggunakan foraminifera sebagai proksi iklim purba (paleoclimate yang baik. Pengambilan sampel dilakukan dengan metode Penampang Stratigrafi Terukur (Measuring Section pada singkapan napal dan batugamping dengan ketebalan mencapai 748,16 sentimeter yang terdiri dari 23 lapisan batuan. Hasil identifikasi dan determinasi fosil foraminifera menunjukkan bahwa pada sampel terdapat 46 spesies bentonik dan 28 spesies planktonik, dengan kisaran umur batuan adalah Eosen Bawah bagian atas (P9 – Eosen Tengah bagian tengah (P11, perubahan batimetri dengan siklus pengendapan inner neritic – upper bathyal - outer neritic. Jumlah spesies yang beragam dan sangat melimpah serta ukuran fosil yang besar menunjukkan nutrisi pada saat itu sangat berlimpah, dengan temperatur 0⁰– 27⁰C sebagai kondisi iklim hangat (warm water. Ralla area is located in Barru District, South Sulawesi Province which consisted of carbonate and volcanic rocks. One of the main components of these rocks is foraminifera fossils, include planktonic and bentonic which founded to be abundance. In determining the age and depositional environment (paleobathymetry, foraminifera fossils could be used as a good paleoclimate proxy. The research was conducted by Stratigraphy Measured (Measuring Section method in marl and limestone outcrop with a thickness of up to 748.16 centimeters which consists of 23 rock layers. Identification and determination of foraminifera fossils suggests that there are 46 bentonic and 28 planktonic species on samples, which are estimated the age of the rocks range from the end of lower Eocene (P9 till the middle of Middle Eocene (P11, bathymetry changes

  11. Evidence of indirect symbiont conferred protection against the predatory lady beetle Harmonia axyridis in the pea aphid.

    Science.gov (United States)

    Kovacs, Jennifer L; Wolf, Candice; Voisin, Dené; Wolf, Seth

    2017-07-11

    Defensive symbionts can provide significant fitness advantages to their hosts. Facultative symbionts can protect several species of aphid from fungal pathogens, heat shock, and parasitism by parasitoid wasps. Previous work found that two of these facultative symbionts can also indirectly protect pea aphids from predation by the lady beetle Hippocampus convergens. When aphids reproduce asexually, there is extremely high relatedness among aphid clone-mates and often very limited dispersal. Under these conditions, symbionts may indirectly protect aphid clone-mates from predation by negatively affecting the survival of a predator after the consumption of aphids harboring the same vertically transmitted facultative symbionts. In this study, we wanted to determine whether this indirect protection extended to another lady beetle species, Harmonia axyridis. We fed Ha. axyridis larvae aphids from one of four aphid sub-clonal symbiont lines which all originated from the same naturally symbiont free clonal aphid lineage. Three of the sub-clonal lines harbor different facultative symbionts that were introduced to the lines via microinjection. Therefore these sub-clonal lineages vary primarily in their symbiont composition, not their genetic background. We found that aphid facultative symbionts affected larval survival as well as pupal survival in their predator Ha. axyridis. Additionally, Ha. axyridis larvae fed aphids with the Regiella symbiont had significantly longer larval developmental times than beetle larvae fed other aphids, and females fed aphids with the Regiella symbiont as larvae weighed less as adults. These fitness effects were different from those previously found in another aphid predator Hi. convergens suggesting that the fitness effects may not be the same in different aphid predators. Overall, our findings suggest that some aphid symbionts may indirectly benefit their clonal aphid hosts by negatively impacting the development and survival of a lady beetle

  12. Experiments with needle bearings

    Science.gov (United States)

    Ferretti, Pericle

    1933-01-01

    Experiments and results are presented in testing needle bearings, especially in comparison with roller bearings. Reduction in coefficient of friction is discussed as well as experimental methods and recording devices.

  13. Acquisition of a Novel Sulfur-Oxidizing Symbiont in the Gutless Marine Worm Inanidrilus exumae

    Science.gov (United States)

    2018-01-01

    ABSTRACT Gutless phallodrilines are marine annelid worms without a mouth or gut, which live in an obligate association with multiple bacterial endosymbionts that supply them with nutrition. In this study, we discovered an unusual symbiont community in the gutless phallodriline Inanidrilus exumae that differs markedly from the microbiomes of all 22 of the other host species examined. Comparative 16S rRNA gene sequence analysis and fluorescence in situ hybridization revealed that I. exumae harbors cooccurring gamma-, alpha-, and deltaproteobacterial symbionts, while all other known host species harbor gamma- and either alpha- or deltaproteobacterial symbionts. Surprisingly, the primary chemoautotrophic sulfur oxidizer “Candidatus Thiosymbion” that occurs in all other gutless phallodriline hosts does not appear to be present in I. exumae. Instead, I. exumae harbors a bacterial endosymbiont that resembles “Ca. Thiosymbion” morphologically and metabolically but originates from a novel lineage within the class Gammaproteobacteria. This endosymbiont, named Gamma 4 symbiont here, had a 16S rRNA gene sequence that differed by at least 7% from those of other free-living and symbiotic bacteria and by 10% from that of “Ca. Thiosymbion.” Sulfur globules in the Gamma 4 symbiont cells, as well as the presence of genes characteristic for autotrophy (cbbL) and sulfur oxidation (aprA), indicate that this symbiont is a chemoautotrophic sulfur oxidizer. Our results suggest that a novel lineage of free-living bacteria was able to establish a stable and specific association with I. exumae and appears to have displaced the “Ca. Thiosymbion” symbionts originally associated with these hosts. IMPORTANCE All 22 gutless marine phallodriline species examined to date live in a highly specific association with endosymbiotic, chemoautotrophic sulfur oxidizers called “Ca. Thiosymbion.” These symbionts evolved from a single common ancestor and represent the ancestral trait for

  14. Foraminifera Population from South Africa Coast Line (Indian and Atlantic Oceans

    Directory of Open Access Journals (Sweden)

    Engin Meriç

    2014-11-01

    Full Text Available Cape Town is the second-largest city of the Republic of South Africa. Research is conducted in 3 different stations: Maori Bay, which lies in the southwest of Cape Town, and Pyramid Rock and Partridge Points which lies in the False Bay, southeast part of Cape Town. Samples are taken from young sediments at 10.00 and 20.00 m depths, and collected by scuba-diving method. The aim of the study is to investigate the living benthic foraminifera assemblages in the Atlantic Ocean, and to compare these assemblages with the southeastern part of the Atlantic Ocean, the Arabian Sea, Indian Ocean and Western Pacific assemblages. Moreover, the aim of the study is to determine whether there are any benthic foraminifera forms reaching to the Mediterranean from Pacific Ocean, Indian Ocean or Red Sea via Suez Channel.

  15. Morphological changes during the ontogeny of Velapertina indigena (Foraminifera) from the Transylvanian Basin (Romania)

    International Nuclear Information System (INIS)

    Kiss, P.; Ruman, A.; Hudackova, N.; Hermanova, Z

    2017-01-01

    Species Velapertina indigena (Luczkowska, 1955) represents common Upper Badenian planktonic foraminifera in the Western Carpathians region. Correct taxonomic determination is often precluded by the complicated ontogenetic evolution resulted into several distinguished morphological stages. In this study the inner shell structures were observed by using tomographic microscope to identify five ontogenetic stages (sensu Brummer). General morphological features of the shell, such as the chamber shape and number, the aperture position and character, the wall texture, and the chambers coiling direction were documented for each stage. The reconstructed ontogenetic model, composed of five ontogenetic stages, was correlated with the 'five stage concept' of Globigerinoides sacculifer. Our study shows potential of the tomographic microscope visualization in improvement of the correct taxonomic classification of non-adult individuals as well as the foraminifera trophic mechanisms interpretation. (authors)

  16. Characterisation of differential mixing of foraminifera and bulk carbonate in NE Atlantic sediments

    International Nuclear Information System (INIS)

    Brown, L.; Cook, G.T.; Mackenzie, A.B.; Naysmith, P.; Anderson, R.; Thomson, J.; Nixon, S.

    2000-01-01

    Radiocarbon age offsets between foraminifera and bulk carbonate samples were investigated in a sediment core from the western Rockall Plateau in the North East Atlantic. Within the surface mixed layer (SML), foraminifera (forams) ages were significantly younger than those of the bulk sediment at corresponding depths. Below the SML, no significant offset was observed between the two, which is in contrast to previous studies. The absence of an offset below the SML may be the result of advective biological mixing dominating over diffusive mixing in the SML, or the foram size fraction being below the threshold at which size selective mixing becomes active. Within the SML, the sampling strategy may bias the collection of forams towards the youngest specimens at each depth

  17. Recent benthic foraminifera and sedimentary facies distribution of the Abu Dhabi (United Arab Emirates) coastline

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen W.

    2014-05-01

    The distribution of benthic foraminifera and sedimentary facies from Recent coastline environments adjacent to the coastline of Abu Dhabi (UAE) was studied in detail with the aim to: 1) provide reliable analogs for understanding and interpreting the depositional environment of ancient shallow-marine sediments from the UAE; 2) assess any modifications in the distribution of benthic environments and sedimentary facies in an area affected by significant anthropogenic activities - particular construction and land reclamation. A total of 100 sea-floor sediment samples were collected in different shallow-marine sedimentary environments (nearshore shelf, beach-front, channels, ooid shoals, lagoon and mangals) close to the coastline of Abu Dhabi Island. Where possible, we revisited the sampling sites used in several studies conducted in the middle of last century (prior to any significant anthropogenic activities) to assess temporal changes in Recent benthic foraminifera and sedimentary facies distribution during the last 50 years. Five foraminiferal assemblages were recognized in the studied area. Species with a porcellaneous test mainly belonging to the genera Quinqueloculina, Triloculina, Spiroloculina, Sigmoilinita are common in all studied areas. Larger benthic foraminifera Peneroplis and Spirolina are particularly abundant in samples collected on seaweed. Hyaline foraminifera mostly belonging to the genera Elphidium, Ammonia, Bolivina and Rosalina are also common together with Miliolidae in the nearshore shelf and beach front. Agglutinated foraminifera (Clavulina, Textularia, Ammobaculites and Reophax) are present in low percentages. The species belonging to the genera Ammobaculites and Reophax are present only in the finest grain samples particularly in lagoons and mangal environments and have not been reported previously in the studied area. The majority of the ooid shoal sediments, the coarser sediments of the beach-front and samples collected in dredged channels

  18. Evidence of indirect symbiont conferred protection against the predatory lady beetle Harmonia axyridis in the pea aphid

    OpenAIRE

    Kovacs, Jennifer L.; Wolf, Candice; Voisin, Den?; Wolf, Seth

    2017-01-01

    Background Defensive symbionts can provide significant fitness advantages to their hosts. Facultative symbionts can protect several species of aphid from fungal pathogens, heat shock, and parasitism by parasitoid wasps. Previous work found that two of these facultative symbionts can also indirectly protect pea aphids from predation by the lady beetle Hippocampus convergens. When aphids reproduce asexually, there is extremely high relatedness among aphid clone-mates and often very limited disp...

  19. 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

  20. Endozoicomonas are specific, facultative symbionts of sea squirts

    Directory of Open Access Journals (Sweden)

    Lars Schreiber

    2016-07-01

    Full Text Available 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, A. 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% to 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.

  1. Comparative Genomics of a Parthenogenesis-Inducing Wolbachia Symbiont

    Science.gov (United States)

    Lindsey, Amelia R. I.; Werren, John H.; Richards, Stephen; Stouthamer, Richard

    2016-01-01

    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. PMID:27194801

  2. Comparative Genomics of a Parthenogenesis-Inducing Wolbachia Symbiont.

    Science.gov (United States)

    Lindsey, Amelia R I; Werren, John H; Richards, Stephen; Stouthamer, Richard

    2016-07-07

    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. Copyright © 2016 Lindsey et al.

  3. 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.

  4. 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.

  5. Combined thermal and herbicide stress in functionally diverse coral symbionts.

    Science.gov (United States)

    van Dam, J W; Uthicke, S; Beltran, V H; Mueller, J F; Negri, A P

    2015-09-01

    Most reef building corals rely on symbiotic microalgae (genus Symbiodinium) to supply a substantial proportion of their energy requirements. Functional diversity of different Symbiodinium genotypes, endorsing the host with physiological advantages, has been widely reported. Yet, the influence of genotypic specificity on the symbiont's susceptibility to contaminants or cumulative stressors is unknown. Cultured Symbiodinium of presumed thermal-tolerant clade D tested especially vulnerable to the widespread herbicide diuron, suggesting important free-living populations may be at risk in areas subjected to terrestrial runoff. Co-exposure experiments where cultured Symbiodinium were exposed to diuron over a thermal stress gradient demonstrated how fast-growing clade C1 better maintained photosynthetic capability than clade D. The mixture toxicity model of Independent Action, considering combined thermal stress and herbicide contamination, revealed response additivity for inhibition of photosynthetic yield in both tested cultures, emphasizing the need to account for cumulative stressor impacts in ecological risk assessment and resource management. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  6. Experimental evolution of a plant pathogen into a legume symbiont.

    Directory of Open Access Journals (Sweden)

    Marta Marchetti

    2010-01-01

    Full Text Available Rhizobia are phylogenetically disparate alpha- and beta-proteobacteria that have achieved the environmentally essential function of fixing atmospheric nitrogen in symbiosis with legumes. Ample evidence indicates that horizontal transfer of symbiotic plasmids/islands has played a crucial role in rhizobia evolution. However, adaptive mechanisms that allow the recipient genomes to express symbiotic traits are unknown. Here, we report on the experimental evolution of a pathogenic Ralstonia solanacearum chimera carrying the symbiotic plasmid of the rhizobium Cupriavidus taiwanensis into Mimosa nodulating and infecting symbionts. Two types of adaptive mutations in the hrpG-controlled virulence pathway of R. solanacearum were identified that are crucial for the transition from pathogenicity towards mutualism. Inactivation of the hrcV structural gene of the type III secretion system allowed nodulation and early infection to take place, whereas inactivation of the master virulence regulator hrpG allowed intracellular infection of nodule cells. Our findings predict that natural selection of adaptive changes in the legume environment following horizontal transfer has been a major driving force in rhizobia evolution and diversification and show the potential of experimental evolution to decipher the mechanisms leading to symbiosis.

  7. Combined thermal and herbicide stress in functionally diverse coral symbionts

    International Nuclear Information System (INIS)

    Dam, J.W. van; Uthicke, S.; Beltran, V.H.; Mueller, J.F.; Negri, A.P.

    2015-01-01

    Most reef building corals rely on symbiotic microalgae (genus Symbiodinium) to supply a substantial proportion of their energy requirements. Functional diversity of different Symbiodinium genotypes, endorsing the host with physiological advantages, has been widely reported. Yet, the influence of genotypic specificity on the symbiont's susceptibility to contaminants or cumulative stressors is unknown. Cultured Symbiodinium of presumed thermal-tolerant clade D tested especially vulnerable to the widespread herbicide diuron, suggesting important free-living populations may be at risk in areas subjected to terrestrial runoff. Co-exposure experiments where cultured Symbiodinium were exposed to diuron over a thermal stress gradient demonstrated how fast-growing clade C1 better maintained photosynthetic capability than clade D. The mixture toxicity model of Independent Action, considering combined thermal stress and herbicide contamination, revealed response additivity for inhibition of photosynthetic yield in both tested cultures, emphasizing the need to account for cumulative stressor impacts in ecological risk assessment and resource management. - Highlights: • Water quality influences thermal stress thresholds in different Symbiodinium types. • Photosystem of clade D tested more sensitive than C1 to a common herbicide. • Increased thermal tolerance quickly countered in presence of herbicide. • Mixture toxicity approach demonstrated response additivity for combined stressors. • Symbiotic partnership may be compromised in areas subjected to terrestrial runoff. - Thermal-tolerant Symbiodinium type D tested especially vulnerable to a common herbicide, emphasizing the significance of cumulative stressors in ecological risk management

  8. Distribution and ecology of Frankliniella occidentalis (Thysanoptera: Thripidae) bacterial symbionts.

    Science.gov (United States)

    Chanbusarakum, Lisa J; Ullman, Diane E

    2009-08-01

    Bacterial populations in Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae) collected in diverse California environments consisted of two bacterial symbionts: BFo-1 and BFo-2 (B = bacteria, Fo = Frankliniella occidentalis, numbers reflect different types). Dual infections of BFo-1 and BFo-2 were found in 50% of the thrips, 18% had neither bacterium, and 24 and 8% were infected solely with BFo-1 and BFo-2, respectively. No other bacteria consistently infected F. occidentalis. Dual infections occurred more often in male thrips and in thrips of both sexes from southern mountain and valley sites. As average collection year or month minimum temperature decreased, infections of BFo-1, alone or in dual infections, increased significantly. As yearly precipitation increased, infection with BFo-1 alone also increased. F. occidentalis color morphology did not affect bacterial infection. BFo-1 created weak biofilms at 25 and 32 degrees C; BFo-2 made strong biofilms at 25 degrees C and no biofilms at 32 degrees C. When the bacteria were grown in culture together, weak biofilms formed at both temperatures studied, although there was no way to determine what each bacterium contributed to the biofilm. BFo-1 and BFo-2 grew at similar rates at 25 and 30 degrees C. Our data show BFo-1 and BFo-2 occur in natural populations of F. occidentalis and support the hypothesis BFo have a symbiotic relationship with F. occidentalis. Regional differences in bacterial prevalence suggest bacterial infection is associated with environmental conditions, and altitude, temperature, and precipitation may be important factors.

  9. Megalodon, mako shark and planktonic foraminifera from the continental shelf off Portugal and their age

    OpenAIRE

    ANTUNES, M.; LEGOINHA, P.; BALBINO, A.

    2015-01-01

    Turbidite fragments collected by a fishing net off the central Portuguese coast (Peniche) present some fossils. The matrix is phosphatized and iron-rich with small quantities of manganese, zinc and copper. The occurrence of Megaselachus megalodon most probably excludes an age older than Middle Miocene. Its very advanced evolution stage is consistent with a Pliocene age. Based on planktonic foraminifera in depressions of cetacean skulls recovered in the same way, from the same area...

  10. Exploring the controls on element ratios in middle Eocene samples of the benthic foraminifera Oridorsalis umbonatus

    Directory of Open Access Journals (Sweden)

    C. F. Dawber

    2012-12-01

    Full Text Available Culturing studies and empirically based core top calibrations have been used to infer that elemental ratios in benthic foraminifera can be used as proxies to reconstruct past variations in bottom water temperature and saturation state (Δ [CO32−]. However the mechanisms linking elemental ratios to these parameters are poorly constrained. Here, we explore the environmental parameters influencing the incorporation of B, Li, Sr and Mg in Oridorsalis umbonatus in early Cenozoic sediments from Ocean Drilling Program Site 1209. We investigate the influence of middle Eocene variations in intermediate water Δ [CO32−] using relationships developed from core top samples. The fidelity of bottom water Δ[CO32−] reconstructions based on single element ratios is assessed by comparing the X/Ca-based reconstructions to each other and to carbon cycle proxy records (benthic foraminifera δ13C, organic carbon content, foraminifera dissolution indices, and a seawater δ18O reconstruction for Site 1209. Discrepancies in the reconstructed Δ[CO32−] values based on these different metal ratios suggest that there are still gaps in our understanding of the parameters influencing X/Ca and demonstrate that caution is required when interpreting palaeo-reconstructions that are derived from a single elemental ratio. The downcore record of O. umbonatus Mg/Ca does not exhibit any similarities with the Li/Ca, B/Ca and Sr/Ca records, suggesting that the environmental parameters influencing Mg/Ca may be different for this species, consistent with temperature as the strongest control on this elemental ratio. This hypothesis is supported by the coefficients of multiple linear regression models on published Mg/Ca data. An incomplete understanding of the controls on elemental incorporation into benthic foraminifera hinders our ability to confidently quantify changes in saturation state using single X/Ca reconstructions over a range of timescales.

  11. The distribution of benthic foraminifera in Bel Torrente submarine cave (Sardinia, Italy) and their environmental significance.

    Science.gov (United States)

    Romano, Elena; Bergamin, Luisa; Pierfranceschi, Giancarlo; Provenzani, Claudio; Marassich, Andrea

    2018-02-01

    The use of benthic foraminifera as ecological indicators in submarine caves of temperate seas have never been studied before and it represents a new approach, verified by this research. The Bel Torrente submarine cave (Gulf of Orosei, Sardinia, Italy) was surveyed by GUE (Global Underwater Explorers) scuba divers in order to georeferencing the cave before positioning the sampling stations, from the entrance to 430 m inside the cave. A total of 15 water samples were collected to investigate abiotic parameters (temperature, salinity, pH) while 15 sediment samples were collected to analyze grain size and benthic foraminifera. Benthic foraminifera, investigated for the first time in a submarine cave of temperate areas, were exclusively found from the entrance to 300 m inside the cave. Species distribution and assemblage diversity have been found to be correlated to the environmental gradient towards the inner cave, mainly due to the decreasing of temperature and salinity and the increasing of the flow energy. Water acidification seems responsible for the transition from a calcareous hyaline-dominated assemblage to an agglutinant-dominated one, occurring between 120 and 150 m from the entrance. Common taxa of the Sardinian coastal marine area are present only close to the entrance of the cave, while species found in the inner part are nearly exclusively epifaunal clinging/attached or infaunal taxa, with tolerance for wide variability of environmental parameters, such as Gavelinopsis praegeri, and opportunist infaunal taxa such as Eggerella advena. The agglutinant taxa found in the cave are conversely very rare in coastal marine assemblages of the area. This suggests a very efficient dispersal mechanism for the colonization of the caves, involving probably juvenile foraminifera at a "propagule" stage. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Predicting the global distribution of planktonic foraminifera using a dynamic ecosystem model

    Directory of Open Access Journals (Sweden)

    I. Fraile

    2008-06-01

    Full Text Available We present a new planktonic foraminifera model developed for the global ocean mixed-layer. The main purpose of the model is to explore the response of planktonic foraminifera to different boundary conditions in the geological past, and to quantify the seasonal bias in foraminifera-based paleoceanographic proxy records. This model is forced with hydrographic data and with biological information taken from an ecosystem model to predict monthly concentrations of the most common planktonic foraminifera species used in paleoceanography: N. pachyderma (sinistral and dextral varieties, G. bulloides, G. ruber (white variety and G. sacculifer. The sensitivity of each species with respect to temperature (optimal temperature and range of tolerance is derived from previous sediment-trap studies.

    Overall, the spatial distribution patterns of most of the species are in agreement with core-top data. N. pachyderma (sin. is limited to polar regions, N. pachyderma (dex. and G. bulloides are the most common species in high productivity zones, while G. ruber and G. sacculifer are more abundant in tropical and subtropical oligotrophic waters. For N. pachyderma (sin and N. pachyderma (dex., the season of maximum production coincides with that observed in sediment-trap records. Model and sediment-trap data for G. ruber and G. sacculifer show, in general, lower concentrations and less seasonal variability at all sites. A sensitivity experiment suggest that, within the temperature-tolerance range of a species, food availability may be the main parameter controlling its abundance.

  13. New and poorly known Middle Jurassic larger benthic foraminifera from the Karst Dinarides of Croatia

    OpenAIRE

    Schlagintweit, Felix; Velić, Ivo

    2011-01-01

    Some new and poorly known larger benthic foraminifera are described from Middle Jurassic (Upper Aalenian-Bajocian) shallow-water limestones of the Croatian Karst Dinarides. Cymbriaella lorigae FUGAGNOLI is reported for the first time beside its type-locality, the Upper Pliensbachian of the Southern Alps. New taxa described include Bosniella bassoulleti n. sp. and Dubrovnikella septfontainei n. gen., n. sp. (family Biokovinidae). Both Cymbriaella lorigae and Everticyclammina praevirguliana FUG...

  14. A note on the laboratory culture of benthic foraminifera collected from nearshore region off Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Nigam, R.; Khare, N.; Koli, N.Y.

    of benthic foraminifera was carried out in two phases. In phase 1 we used living organisms collected from the field as parent to be cultured under laboratory conditions using filtered sea water as media. This attempt was made to obtain the offsprings... responded to culture. (2) Food has conducive effect (3) The formation of initial chambers took less time as compared to latter chambers. Fig. 1 shows the growth of successive chambers. However, some of the parents reproduced at varying intervals...

  15. Mg isotope fractionation in biogenic carbonates of deep-sea coral, benthic foraminifera, and hermatypic coral.

    Science.gov (United States)

    Yoshimura, Toshihiro; Tanimizu, Masaharu; Inoue, Mayuri; Suzuki, Atsushi; Iwasaki, Nozomu; Kawahata, Hodaka

    2011-11-01

    High-precision Mg isotope measurements by multiple collector inductively coupled plasma mass spectrometry were applied for determinations of magnesium isotopic fractionation of biogenic calcium carbonates from seawater with a rapid Mg purification technique. The mean δ(26)Mg values of scleractinian corals, giant clam, benthic foraminifera, and calcite deep-sea corals were -0.87‰, -2.57‰, -2.34‰, and -2.43‰, suggesting preferential precipitation of light Mg isotopes to produce carbonate skeleton in biomineralization. Mg isotope fractionation in deep-sea coral, which has high Mg calcite skeleton, showed a clear temperature (T) dependence from 2.5 °C to 19.5 °C: 1,000 × ln(α) = -2.63 (±0.076) + 0.0138 (±0.0051) × T(R(2) = 0.82, p coral. Since the precipitation rates of deep-sea coral and benthic foraminifera are several orders of magnitude different, the results suggest that kinetic isotope fractionation may not be a major controlling factor for high-Mg calcite. The Mg isotope fractionation factors and the slope of temperature dependence from deep-sea corals and benthic foraminifera are similar to that for an inorganically precipitated calcite speleothem. Taking into account element partitioning and the calcification rate of biogenic CaCO(3), the similarity among inorganic minerals, deep-sea corals, and benthic foraminiferas may indicate a strong mineralogical control on Mg isotope fractionation for high-Mg calcite. On the other hand, δ(26)Mg in hermatypic corals composed of aragonite has been comparable with previous data on biogenic aragonite of coral, sclerosponges, and scaphopad, regardless of species differences of samples.

  16. Foraminifera and sedimentary facies distribution changes along the Abu Dhabi (UAE) coastline over the last 50 years

    Science.gov (United States)

    Fiorini, Flavia; Lokier, Stephen

    2013-04-01

    Changes in Recent benthic foraminifera and sedimentary facies distribution along the coastline of Abu Dhabi, United Arab Emirates (UAE) were assessed. Anthropogenic activities are modifying the morphology of the coastline causing changes to coastal sedimentary systems. During the early 1960's, prior to any major construction activities, a number of studies examined the distribution of shallow-marine foraminifera and sedimentary facies in the shallow off-shore coastal zone of Abu Dhabi providing a good overall assessment of the distribution of sedimentary facies and foraminifera prior to the anthropogenic activities. The present study revisited, the sampling sites used in the studies conducted in the 1960's. One hundred sea-floor sediment samples were collected, proximal to the coastline of Abu Dhabi Island in nearshore shelf, beach front, channels, ooid shoals and lagoonal settings. Samples were collected at a water depth of 1 to 15m in water with a temperature of 22-29˚C and a salinity of 40-46‰. The identified foraminifera consist mainly of species with a porcellaneous test belonging to the genera Quinqueloculina, Triloculina, Spiroloculina, Sigmoilinita. Larger benthic foraminifera mainly belonging to the genera Peneroplis and Spirolina are particularly abundant in samples collected on seaweed. Hyaline foraminifera mostly belonging to the genera Elphidium, Ammonia, Bolivina and Rosalina are also common together with Miliolidae in the nearshore shelf and beach front. Agglutinated foraminifera (Clavulina, Textularia, Ammobaculites and Reophax) are present in low percentages. Among the agglutinated foraminifera the species belonging to the genera Ammobaculites and Reophax are present only in the finest grain samples and have not reported previously in the studied area. The majority of the oolith shoal sediments, the coarser sediments of the beach front and samples collected in dredged channels do not contain living foraminifera and the dead assemblage is mostly

  17. 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.

  18. 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

    Tenuibacter priapulorum’. Within Rickettsiales, they form a phylogenetically well-defined, family-level clade with uncultured symbionts of marine, terrestrial, and freshwater arthropods. Cand. Tenuibacter priapulorum expands the host range of this candidate family from Arthropoda to the entire Ecdysozoa...

  19. The Response of Living Benthic Foraminifera at an Organically Polluted Locality in Eastern Bahrain

    Science.gov (United States)

    Arslan, Muhammad; Kaminski, Michael; Frontalini, Fabrizio

    2017-04-01

    This study examines the response of living benthic foraminifera at a polluted site in eastern Bahrain, with the aim to determine the effects of anthropogenic pollution on their distribution patterns and the occurrence of morphological deformities. The boat harbor in Askar (Bahrain) is subjected to pollution by nutrients, organic matter, and hydrocarbons. Foraminiferal density is found to be higher at the polluted site compared with a nearby unpolluted site, suggesting a higher amount of available food for the benthic foraminifera. Seven taxonomical groups were recognized in the organically polluted transect including Ammonia, Glabratellina, Murrayinella, Elphidium, Brizalina, miliolids, and peneroplids. By comparing the foraminiferal assemblages with a nearby unpolluted transect, the genus Murrayinella appeared to be a dominant and pervasive taxon that was able to proliferate in an organically polluted environment. Strong correlations of Murrayinella with nitrates, sulfates, TOC, and THC put forward the opportunistic behavior of this taxon. Our results contrast with previously published findings on modern foraminiferal assemblage in the Arabian Gulf, as Murrayinella is rarely reported. The population of miliolids was drastically reduced at the polluted site, which suggests that the group was adversely affected by organic pollution when compared with the unpolluted transect. This reaffirms the sensitive nature of the miliolid group of foraminifera, supporting the findings of previous studies of the effect of historical coastal eutrophication on foraminiferal assemblages in the Gulf of Mexico and Japan. Therefore, the miliolids might be considered as a pollution proxy for future biomonitoring studies in the Gulf region.

  20. Species distribution and depth habitat of recent planktic foraminifera in Fram Strait, Arctic Ocean

    Directory of Open Access Journals (Sweden)

    Theodora Pados

    2014-05-01

    Full Text Available To describe the horizontal and vertical distribution of recent planktic foraminifera in Fram Strait (Arctic, plankton samples were collected in the early summer of 2011 using a MultiNet sampler (>63 µm at 10 stations along a west–east transect at 78°50′N. Five depth intervals were sampled from the sea surface down to 500 m. Additionally, sediment surface samples from the same locations were analysed. The ratio between absolute abundances of planktic foraminifera in the open ocean, at the ice margin and in the ice-covered ocean was found to be approximately 2:4:1. The assemblage was dominated by the polar Neogloboquadrina pachyderma (sin. and the subpolar Turborotalita quinqueloba, which accounted for 76 and 15% of all tests in the warm, saline Atlantic waters and 90 and 5% in the cold and fresh Polar waters, respectively. Both species had maximum absolute abundances between 0 and 100 m water depth, however, they apparently lived shallower under the ice cover than under ice-free conditions. This indicates that the depth habitat of planktic foraminifera in the study area is predominantly controlled by food availability and not by temperature. The distribution pattern obtained by plankton tows was clearly reflected on the sediment surface and we conclude that the assemblage on the sediment surface can be used as an indicator for modern planktic foraminiferal fauna.

  1. Time-response of cultured deep-sea benthic foraminifera to different algal diets

    Science.gov (United States)

    Heinz, P.; Hemleben, Ch; Kitazato, H.

    2002-03-01

    The vertical distribution of benthic foraminifera in the surface sediment is influenced by environmental factors, mainly by food and oxygen supply. An experiment of three different time series was performed to investigate the response of deep-sea benthic foraminifera to simulated phytodetritus pulses under stable oxygen concentrations. Each series was fed constantly with one distinct algal species in equivalent amounts. The temporal reactions of the benthic foraminifera with regard to the vertical distribution in the sediment, the total number, and the species composition were observed and compared within the three series. Additionally, oxygen contents and bacterial cell numbers were measured to ensure that these factors were invariable and did not influence foraminiferal communities. The addition of algae leads to higher population densities 21 days after food was added. Higher numbers of individuals were probably caused by higher organic levels, which in turn induced reproduction. A stronger response is found after feeding with Amphiprora sp. and Pyramimonas sp., compared to Dunaliella tertiolecta. At a constant high oxygen supply, no migration to upper layers was observed after food addition, and more individuals were found in deeper layers. The laboratory results thus agree with the predictions of the TROX-model. An epifaunal microhabitat preference was shown for Adercotryma glomerata. Hippocrepina sp. was spread over the entire sediment depth with a shallow infaunal maximum. Melonis barleeanum preferred a deeper infaunal habitat. Bacterial cell concentrations were stable during the laboratory experiments and showed no significant response to higher organic fluxes.

  2. Towards radiocarbon dating of single foraminifera with a gas ion source

    Science.gov (United States)

    Wacker, L.; Lippold, J.; Molnár, M.; Schulz, H.

    2013-01-01

    Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 μg for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO2 is liberated from 150 to 1150 μg of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO2 is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 μg (50 μg C) typically gives a 12C- ion source current of 10-15 μA over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 μg Cibicides pseudoungerianus test at 14,030 ± 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.

  3. Towards radiocarbon dating of single foraminifera with a gas ion source

    International Nuclear Information System (INIS)

    Wacker, L.; Lippold, J.; Molnár, M.; Schulz, H.

    2013-01-01

    Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 μg for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO 2 is liberated from 150 to 1150 μg of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO 2 is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 μg (50 μg C) typically gives a 12 C − ion source current of 10–15 μA over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 μg Cibicides pseudoungerianus test at 14,030 ± 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.

  4. Towards radiocarbon dating of single foraminifera with a gas ion source

    Energy Technology Data Exchange (ETDEWEB)

    Wacker, L., E-mail: wacker@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Lippold, J. [Heidelberg Academy of Sciences, 69120 Heidelberg (Germany); Molnar, M. [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Institute of Nuclear Research, Hungarian Academy of Sciences, 4026 Debrecen (Hungary); Schulz, H. [Institute for Geosciencies, University of Tuebingen, 72076 Tuebingen (Germany)

    2013-01-15

    Carbonate shells from foraminifera are often analysed for radiocarbon to determine the age of deep-sea sediments or to assess radiocarbon reservoir ages. However, a single foraminiferal test typically contains only a few micrograms of carbon, while most laboratories require more than 100 {mu}g for radiocarbon dating with an accelerator mass spectrometry (AMS) system. The collection of the required amount of foraminifera for a single analyses is therefore time consuming and not always possible. Here, we present a convenient method to measure the radiocarbon content of foraminifera using an AMS system fitted with a gas ion source. CO{sub 2} is liberated from 150 to 1150 {mu}g of carbonate in septum sealed vials by acid decomposition of the carbonate. The CO{sub 2} is collected on a zeolite trap and subsequently transferred to a syringe from where it is delivered to the ion source. A sample of 400 {mu}g (50 {mu}g C) typically gives a {sup 12}C{sup -} ion source current of 10-15 {mu}A over 20 min, yielding a measurement precision of less than 7 per mil for a modern sample. Using this method, we were able to date a single 560 {mu}g Cibicides pseudoungerianus test at 14,030 {+-} 160 radiocarbon years. Only a minor modification to our existing gas handling system was required and the system is fully automatable to further reduce the effort involved for sample preparation.

  5. Foraminifera Models to Interrogate Ostensible Proxy-Model Discrepancies During Late Pliocene

    Science.gov (United States)

    Jacobs, P.; Dowsett, H. J.; de Mutsert, K.

    2017-12-01

    Planktic foraminifera faunal assemblages have been used in the reconstruction of past oceanic states (e.g. the Last Glacial Maximum, the mid-Piacenzian Warm Period). However these reconstruction efforts have typically relied on inverse modeling using transfer functions or the modern analog technique, which by design seek to translate foraminifera into one or two target oceanic variables, primarily sea surface temperature (SST). These reconstructed SST data have then been used to test the performance of climate models, and discrepancies have been attributed to shortcomings in climate model processes and/or boundary conditions. More recently forward proxy models or proxy system models have been used to leverage the multivariate nature of proxy relationships to their environment, and to "bring models into proxy space". Here we construct ecological models of key planktic foraminifera taxa, calibrated and validated with World Ocean Atlas (WO13) oceanographic data. Multiple modeling methods (e.g. multilayer perceptron neural networks, Mahalanobis distance, logistic regression, and maximum entropy) are investigated to ensure robust results. The resulting models are then driven by a Late Pliocene climate model simulation with biogeochemical as well as temperature variables. Similarities and differences with previous model-proxy comparisons (e.g. PlioMIP) are discussed.

  6. Carbon isotopic fractionation in live benthic foraminifera -comparison with inorganic precipitate studies

    International Nuclear Information System (INIS)

    Grossmann, E.L.

    1984-01-01

    Carbon and oxygen isotopic analyses have been performed on live-stained aragonitic and calcitic benthic foraminifera and dissolved inorganic carbon from the Southern California Borderland to examine carbon isotopic fractionation in foraminifera. Temperature, salinity and pH data have also been collected to permit accurate determination of the delta 13 C of bicarbonate ion and thus aragonite-HCO 3 - and calcite-HCO 3 - isotopic enrichment factors (epsilonsub(ar-b) and epsilonsub(cl-b), respectively). Only species which precipitate in 18 O equilibrium have been considered. epsilonsub (ar-b) values based on Hoeglundina elegans range from 1.9 per mille at 2.7 deg C to 1.1 per mille at 9.5 deg C. The temperature dependence of epsilonsub(ar-b) is considerably greater than the equilibrium equation would predict and may be due to a vital effect. The calcitic foraminifera Cassidulina tortuosa, Cassidulina braziliensis, and Cassidulina limbata, Bank and Terrace dwellers, have similar delta 13 C values and yield an average epsilonsub(cl-b) value of -0.2 +- 0.1 per mille between 8 deg and 10 deg C. Calcitic Uvigerina curticosta, Uvigerina peregrina, and megalospheric B, argentea, Slope and Basin dwellers, are -0.7 +- 0.1 per mille enriched relative to ambient bicarbonate for 3 to 9 deg C. (author)

  7. The trophic and metabolic pathways of foraminifera in the Arabian Sea: evidence from cellular stable isotopes

    Science.gov (United States)

    Jeffreys, R. M.; Fisher, E. H.; Gooday, A. J.; Larkin, K. E.; Billett, D. S. M.; Wolff, G. A.

    2015-03-01

    The Arabian Sea is a region of elevated productivity with the highest globally recorded fluxes of particulate organic matter (POM) to the deep ocean, providing an abundant food source for fauna at the seafloor. However, benthic communities are also strongly influenced by an intense oxygen minimum zone (OMZ), which impinges on the continental slope from 100 to 1000 m water depth. We compared the trophic ecology of foraminifera on the Oman and Pakistan margins of the Arabian Sea (140-3185 m water depth). These two margins are contrasting both in terms of the abundance of sedimentary organic matter and the intensity of the OMZ. Organic carbon concentrations of surficial sediments were higher on the Oman margin (3.32 ± 1.4%) compared to the Pakistan margin (2.45 ± 1.1%) and sedimentary organic matter (SOM) quality estimated from the Hydrogen Index was also higher on the Oman margin (300-400 mg HC mg TOC-1) compared to the Pakistan margin (responsible for the differences observed in foraminiferal isotopic composition. In addition, at the time of sampling, whole jellyfish carcasses (Crambionella orsini) and a carpet of jelly detritus were observed across the Oman margin transect. Associated chemosynthetic bacteria may have provided an organic-rich food source for foraminifera at these sites. Our data suggest that foraminifera in OMZ settings can utilise a variety of food sources and metabolic pathways to meet their energetic demands.

  8. 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.

  9. Candidatus Sodalis melophagi sp. nov.: phylogenetically independent comparative model to the tsetse fly symbiont Sodalis glossinidius.

    Directory of Open Access Journals (Sweden)

    Tomáš Chrudimský

    Full Text Available Bacteria of the genus Sodalis live in symbiosis with various groups of insects. The best known member of this group, a secondary symbiont of tsetse flies Sodalis glossinidius, has become one of the most important models in investigating establishment and evolution of insect-bacteria symbiosis. It represents a bacterium in the early/intermediate state of the transition towards symbiosis, which allows for exploring such interesting topics as: usage of secretory systems for entering the host cell, tempo of the genome modification, and metabolic interaction with a coexisting primary symbiont. In this study, we describe a new Sodalis species which could provide a useful comparative model to the tsetse symbiont. It lives in association with Melophagus ovinus, an insect related to tsetse flies, and resembles S. glossinidius in several important traits. Similar to S. glossinidius, it cohabits the host with another symbiotic bacterium, the bacteriome-harbored primary symbiont of the genus Arsenophonus. As a typical secondary symbiont, Candidatus Sodalis melophagi infects various host tissues, including bacteriome. We provide basic morphological and molecular characteristics of the symbiont and show that these traits also correspond to the early/intermediate state of the evolution towards symbiosis. Particularly, we demonstrate the ability of the bacterium to live in insect cell culture as well as in cell-free medium. We also provide basic characteristics of type three secretion system and using three reference sequences (16 S rDNA, groEL and spaPQR region we show that the bacterium branched within the genus Sodalis, but originated independently of the two previously described symbionts of hippoboscoids. We propose the name Candidatus Sodalis melophagi for this new bacterium.

  10. Candidatus Sodalis melophagi sp. nov.: phylogenetically independent comparative model to the tsetse fly symbiont Sodalis glossinidius.

    Science.gov (United States)

    Chrudimský, Tomáš; Husník, Filip; Nováková, Eva; Hypša, Václav

    2012-01-01

    Bacteria of the genus Sodalis live in symbiosis with various groups of insects. The best known member of this group, a secondary symbiont of tsetse flies Sodalis glossinidius, has become one of the most important models in investigating establishment and evolution of insect-bacteria symbiosis. It represents a bacterium in the early/intermediate state of the transition towards symbiosis, which allows for exploring such interesting topics as: usage of secretory systems for entering the host cell, tempo of the genome modification, and metabolic interaction with a coexisting primary symbiont. In this study, we describe a new Sodalis species which could provide a useful comparative model to the tsetse symbiont. It lives in association with Melophagus ovinus, an insect related to tsetse flies, and resembles S. glossinidius in several important traits. Similar to S. glossinidius, it cohabits the host with another symbiotic bacterium, the bacteriome-harbored primary symbiont of the genus Arsenophonus. As a typical secondary symbiont, Candidatus Sodalis melophagi infects various host tissues, including bacteriome. We provide basic morphological and molecular characteristics of the symbiont and show that these traits also correspond to the early/intermediate state of the evolution towards symbiosis. Particularly, we demonstrate the ability of the bacterium to live in insect cell culture as well as in cell-free medium. We also provide basic characteristics of type three secretion system and using three reference sequences (16 S rDNA, groEL and spaPQR region) we show that the bacterium branched within the genus Sodalis, but originated independently of the two previously described symbionts of hippoboscoids. We propose the name Candidatus Sodalis melophagi for this new bacterium.

  11. Teddy Bear Stories

    DEFF Research Database (Denmark)

    van Leeuwen, Theo; Caldas-Coulthardt, Carmen

    2014-01-01

    This paper presents a semiotic analysis of a key cultural artefact, the teddy bear. After introducing the iconography of the teddy bear, it analyses different kinds of stories to show how teddy bears are endowed with meaning in everyday life: stories from children's books, reminiscenses by adults...... about their childhood teddy bears, and children's accounts of what they do with teddy bears, both written for school and told 'out of school', The chapter sees teddy bears as artefacts that provide a cultural channeling for the child's need of a transitional object and argues that the meanings of teddy...... bears have traditionally centred on interpersonal relations within the nuclear family, but have recently been institutionalized and commercialized....

  12. Planktonic foraminifera-derived environmental DNA extracted from abyssal sediments preserves patterns of plankton macroecology

    Directory of Open Access Journals (Sweden)

    R. Morard

    2017-06-01

    Full Text Available Deep-sea sediments constitute a unique archive of ocean change, fueled by a permanent rain of mineral and organic remains from the surface ocean. Until now, paleo-ecological analyses of this archive have been mostly based on information from taxa leaving fossils. In theory, environmental DNA (eDNA in the sediment has the potential to provide information on non-fossilized taxa, allowing more comprehensive interpretations of the fossil record. Yet, the process controlling the transport and deposition of eDNA onto the sediment and the extent to which it preserves the features of past oceanic biota remains unknown. Planktonic foraminifera are the ideal taxa to allow an assessment of the eDNA signal modification during deposition because their fossils are well preserved in the sediment and their morphological taxonomy is documented by DNA barcodes. Specifically, we re-analyze foraminiferal-specific metabarcodes from 31 deep-sea sediment samples, which were shown to contain a small fraction of sequences from planktonic foraminifera. We confirm that the largest portion of the metabarcode originates from benthic bottom-dwelling foraminifera, representing the in situ community, but a small portion (< 10 % of the metabarcodes can be unambiguously assigned to planktonic taxa. These organisms live exclusively in the surface ocean and the recovered barcodes thus represent an allochthonous component deposited with the rain of organic remains from the surface ocean. We take advantage of the planktonic foraminifera portion of the metabarcodes to establish to what extent the structure of the surface ocean biota is preserved in sedimentary eDNA. We show that planktonic foraminifera DNA is preserved in a range of marine sediment types, the composition of the recovered eDNA metabarcode is replicable and that both the similarity structure and the diversity pattern are preserved. Our results suggest that sedimentary eDNA could preserve the ecological structure of

  13. Low Latitude Pelagic Foraminifera Found in the Hudson River: Are They Hurricane Deposits?

    Science.gov (United States)

    Monahan, K. M.; Abbott, D. H.; Hoenisch, B.; Breger, D.

    2011-12-01

    River sediment cores provide a record of past environmental changes through stacked layers of sediments. In core CD02-29A, recovered from the southern Hudson River, a significant number of tropical planktic foraminifer tests were found. Foraminifera were concentrated in sediment layers of low impedance, suggesting high carbonate content. Because modern planktic foraminifera are exclusively marine, their presence in Hudson sediments in the core was remarkable. We can think of only two mechanisms that could explain this observation: either living specimens are carried upriver with the daily tides, or storm surges carry large amounts of seawater and re-suspended marine sediment upriver. To test for the presence of living specimens in Hudson River water, plankton tow samples were collected during high tide at the Hudson Battery south of the sample site, and at Piermont Pier north of the sample site and no living foraminifera were found. In addition, oxygen isotope (δ18O) analyses reveal a marine composition but the large difference in δ18O between the two surface dwelling species Globigerinoides ruber (pink) and Globigerinoides sacculifer, picked from the same sediment layer, suggests re-suspension and mixing of marine sediment deposits. Because only planktic, tropical to subtropical foraminiferal assemblages were found, the Hudson River deposits differ from previously recorded storm deposits found on Long Island and in New Jersey. In particular, the foraminiferal assemblages contain up to 40% G. ruber (pink), suggesting a highly tropical signal from a location where abundances of G. ruber are very low. This data, in addition to the pulsed occurrence of tests in the sediment suggests that the introduction of planktic foraminifera into the Hudson River must be driven by rare events. We suggest that storm surges from rare high-intensity hurricanes most likely explain the presence of these tests in Hudson River sediments, possibly assisted by the Gulf Stream entraining

  14. 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.

  15. Orally Delivered Scorpion Antimicrobial Peptides Exhibit Activity against Pea Aphid (Acyrthosiphon pisum and Its Bacterial Symbionts

    Directory of Open Access Journals (Sweden)

    Karen Luna-Ramirez

    2017-08-01

    Full Text Available Aphids are severe agricultural pests that damage crops by feeding on phloem sap and vectoring plant pathogens. Chemical insecticides provide an important aphid control strategy, but alternative and sustainable control measures are required to avoid rapidly emerging resistance, environmental contamination, and the risk to humans and beneficial organisms. Aphids are dependent on bacterial symbionts, which enable them to survive on phloem sap lacking essential nutrients, as well as conferring environmental stress tolerance and resistance to parasites. The evolution of aphids has been accompanied by the loss of many immunity-related genes, such as those encoding antibacterial peptides, which are prevalent in other insects, probably because any harm to the bacterial symbionts would inevitably affect the aphids themselves. This suggests that antimicrobial peptides (AMPs could replace or at least complement conventional insecticides for aphid control. We fed the pea aphids (Acyrthosiphon pisum with AMPs from the venom glands of scorpions. The AMPs reduced aphid survival, delayed their reproduction, displayed in vitro activity against aphid bacterial symbionts, and reduced the number of symbionts in vivo. Remarkably, we found that some of the scorpion AMPs compromised the aphid bacteriome, a specialized organ that harbours bacterial symbionts. Our data suggest that scorpion AMPs holds the potential to be developed as bio-insecticides, and are promising candidates for the engineering of aphid-resistant crops.

  16. 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] and are vertic......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......] 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...... suggests that the symbiosis has been stably maintained over evolutionary time dating back to the last common lumbricid earthworm ancestor. How this evolutionarily stable association is maintained is unknown; symbiont-free worms can be reared in lab culture and therefore the symbionts are not essential...

  17. 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.

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

    Directory of Open Access Journals (Sweden)

    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

  19. Novel bacteriocyte-associated pleomorphic symbiont of the grain pest beetleRhyzopertha dominica(Coleoptera: Bostrichidae).

    Science.gov (United States)

    Okude, Genta; Koga, Ryuichi; Hayashi, Toshinari; Nishide, Yudai; Meng, Xian-Ying; Nikoh, Naruo; Miyanoshita, Akihiro; Fukatsu, Takema

    2017-01-01

    The lesser grain borer Rhyzopertha dominica (Coleoptera: Bostrichidae) is a stored-product pest beetle. Early histological studies dating back to 1930s have reported that R. dominica and other bostrichid species possess a pair of oval symbiotic organs, called the bacteriomes, in which the cytoplasm is densely populated by pleomorphic symbiotic bacteria of peculiar rosette-like shape. However, the microbiological nature of the symbiont has remained elusive. Here we investigated the bacterial symbiont of R. dominica using modern molecular, histological, and microscopic techniques. Whole-mount fluorescence in situ hybridization specifically targeting symbiotic bacteria consistently detected paired bacteriomes, in which the cytoplasm was full of pleomorphic bacterial cells, in the abdomen of adults, pupae and larvae, confirming previous histological descriptions. Molecular phylogenetic analysis identified the symbiont as a member of the Bacteroidetes, in which the symbiont constituted a distinct bacterial lineage allied to a variety of insect-associated endosymbiont clades, including Uzinura of diaspidid scales, Walczuchella of giant scales, Brownia of root mealybugs, Sulcia of diverse hemipterans, and Blattabacterium of roaches. The symbiont gene exhibited markedly AT-biased nucleotide composition and significantly accelerated molecular evolution, suggesting degenerative evolution of the symbiont genome. The symbiotic bacteria were detected in oocytes and embryos, confirming continuous host-symbiont association and vertical symbiont transmission in the host life cycle. We demonstrate that the symbiont of R. dominica constitutes a novel bacterial lineage in the Bacteroidetes. We propose that reductive evolution of the symbiont genome may be relevant to the amorphous morphology of the bacterial cells via disruption of genes involved in cell wall synthesis and cell division. Genomic and functional aspects of the host-symbiont relationship deserve future studies.

  20. Sodium chloride accumulation in glycophyte plants with cyanobacterial symbionts.

    Science.gov (United States)

    Green, Thomas George Allan; Sancho, Leopoldo G; Pintado, Ana; Saco, Dolores; Martín, Soledad; Arróniz-Crespo, María; Angel Casermeiro, Miguel; de la Cruz Caravaca, Maria Teresa; Cameron, Steven; Rozzi, Ricardo

    2017-11-01

    The majority of plant species are glycophytes and are not salt-tolerant and maintain low sodium levels within their tissues; if . high tissue sodium concentrations do occur, it is in response to elevated environmental salt levels. Here we report an apparently novel and taxonomically diverse grouping of plants that continuously maintain high tissue sodium contents and share the rare feature of possessing symbiotic cyanobacteria. Leaves of Gunnera magellanica in Tierra del Fuego always had sodium contents (dry weight basis) of around 4.26 g kg -1 , about 20 times greater than measured in other higher plants in the community (0.29 g kg -1 ). Potassium and chloride levels were also elevated. This was not a response to soil sodium and chloride levels as these were low at all sites. High sodium contents were also confirmed in G. magellanica from several other sites in Tierra del Fuego, in plants taken to, and cultivated in Madrid for 2 years at low soil salt conditions, and also in other free living or cultivated species of Gunnera from the UK and New Zealand. Gunnera species are the only angiosperms that possess cyanobacterial symbionts so we analysed other plants that have this rather rare symbiosis, all being glycophytes. Samples of Azolla , a floating aquatic fern, from Europe and New Zealand all had even higher sodium levels than Gunnera . Roots of the gymnosperm Cycas revoluta had lower sodium contents (2.52 ± 0.34 g kg -1 ) but still higher than the non-symbiotic glycophytes. The overaccumulation of salt even when it is at low levels in the environment appears to be linked to the possession of a cyanobacterial symbiosis although the actual functional basis is unclear.

  1. Accessing carboxylesterase diversity from termite hindgut symbionts through metagenomics.

    Science.gov (United States)

    Rashamuse, Konanani; Mabizela-Mokoena, Nobalanda; Sanyika, Tendai Walter; Mabvakure, Batsirai; Brady, Dean

    2012-01-01

    A shotgun metagenomic library was constructed from termite hindgut symbionts and subsequently screened for esterase activities. A total of 68 recombinant clones conferring esterolytic phenotypes were identified, of which the 14 most active were subcloned and sequenced. The nucleotide lengths of the esterase-encoding open reading frames (ORFs) ranged from 783 to 2,592 bp and encoded proteins with predicted molecular masses of between 28.8 and 97.5 kDa. The highest identity scores in the GenBank database, from a global amino acid alignment ranged from 39 to 83%. The identified ORFs revealed the presence of the G-X-S-X-D, G-D-S-X, and S-X-X-K sequence motifs that have been reported to harbour a catalytic serine residue in other previously reported esterase primary structures. Five of the ORFs (EstT5, EstT7, EstT9, EstT10, and EstT12) could not be classified into any of the original eight esterase families. One of the ORFs (EstT9) showed a unique primary structure consisting of an amidohydrolase-esterase fusion. Six of the 14 esterase-encoding genes were recombinantly expressed in Escherichia coli and the purified enzymes exhibited temperature optima of between 40-50°C. Substrate-profiling studies revealed that the characterised enzymes were 'true' carboxylesterases based on their preferences for short to medium chain length p-nitrophenyl ester substrates. This study has demonstrated a successful application of a metagenomic approach in accessing novel esterase-encoding genes from the gut of termites that could otherwise have been missed by classical culture enrichment approaches. Copyright © 2012 S. Karger AG, Basel.

  2. Bearings: Technology and needs

    Science.gov (United States)

    Anderson, W. J.

    1982-01-01

    A brief status report on bearing technology and present and near-term future problems that warrant research support is presented. For rolling element bearings a material with improved fracture toughness, life data in the low Lambda region, a comprehensive failure theory verified by life data and incorporated into dynamic analyses, and an improved corrosion resistant alloy are perceived as important needs. For hydrodynamic bearings better definition of cavitation boundaries and pressure distributions for squeeze film dampers, and geometry optimization for minimum power loss in turbulent film bearings are needed. For gas film bearings, foil bearing geometries that form more nearly optimum film shapes for maximum load capacity, and more effective surface protective coatings for high temperature operation are needed.

  3. Polar bears, Ursus maritimus

    Science.gov (United States)

    Rode, Karyn D.; Stirling, Ian

    2017-01-01

    Polar bears are the largest of the eight species of bears found worldwide and are covered in a pigment-free fur giving them the appearance of being white. They are the most carnivorous of bear species consuming a high-fat diet, primarily of ice-associated seals and other marine mammals. They range throughout the circumpolar Arctic to the southernmost extent of seasonal pack ice.

  4. EcoBears

    DEFF Research Database (Denmark)

    Nielsen, Nick; Pedersen, Sandra Bleuenn; Sørensen, Jens Ager

    2015-01-01

    In this paper, we introduce the EcoBears concept that aims to augment household appliances with functional and aesthetic features to promote their "use'' and "longevity of use'' to prevent their disposal. The EcoBears also aim to support the communication of environmental issues in the home setting....... We present our initial design and implementation of the EcoBears that consist of two bear modules (a mother and her cub). We also present our preliminary concept validations and lessons learned to be considered for future directions....

  5. 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.

  6. Intracellular Oceanospirillales inhabit the gills of the hydrothermal vent snail Alviniconcha with chemosynthetic, γ-Proteobacterial symbionts.

    Science.gov (United States)

    Beinart, R A; Nyholm, S V; Dubilier, N; Girguis, P R

    2014-12-01

    Associations between bacteria from the γ-Proteobacterial order Oceanospirillales and marine invertebrates are quite common. Members of the Oceanospirillales exhibit a diversity of interactions with their various hosts, ranging from the catabolism of complex compounds that benefit host growth to attacking and bursting host nuclei. Here, we describe the association between a novel Oceanospirillales phylotype and the hydrothermal vent snail Alviniconcha. Alviniconcha typically harbour chemoautotrophic γ- or ε-Proteobacterial symbionts inside their gill cells. Via fluorescence in situ hybridization and transmission electron microscopy, we observed an Oceanospirillales phylotype (named AOP for ‘Alviniconcha Oceanospirillales phylotype’) in membrane-bound vacuoles that were separate from the known γ- or ε-Proteobacterial symbionts. Using quantitative polymerase chain reaction, we surveyed 181 Alviniconcha hosting γ-Proteobacterial symbionts and 102 hosting ε-Proteobacterial symbionts, and found that the population size of AOP was always minor relative to the canonical symbionts (median 0.53% of the total quantified 16S rRNA genes). Additionally, we detected AOP more frequently in Alviniconcha hosting γ-Proteobacterial symbionts than in those hosting ε-Proteobacterial symbionts (96% and 5% of individuals respectively). The high incidence of AOP in γ-Proteobacteria hosting Alviniconcha implies that it could play a significant ecological role either as a host parasite or as an additional symbiont with unknown physiological capacities.

  7. 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.

  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. 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

  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. Fluorine lubricated bearing technology

    Science.gov (United States)

    Mallaire, F. R.

    1973-01-01

    An experimental program was conducted to evaluate and select materials for ball bearings intended for use in liquid fluorine and/or FLOX. The ability of three different ball-separator materials, each containing nickel, to form and transfer a nickel fluoride film to provide effective lubrication at the required areas of a ball bearing operating in liquid fluorine was evaluated. In addition, solid lubrication of a ball bearing operating in liquid fluorine by either a fused fluoride coating applied to all surfaces of the ball separator or by a fluoride impregnation of porous sintered material ball separators was evaluated. Less bearing wear occurred when tests were conducted in the less reactive FLOX. Bearings fabricated from any of the materials tested would have relatively short wear lives and would require frequent replacement in a reusable engine.

  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. SSU rDNA divergence in planktonic foraminifera: molecular taxonomy and biogeographic implications.

    Directory of Open Access Journals (Sweden)

    Aurore André

    Full Text Available The use of planktonic foraminifera in paleoceanography requires taxonomic consistency and precise assessment of the species biogeography. Yet, ribosomal small subunit (SSUr DNA analyses have revealed that most of the modern morpho-species of planktonic foraminifera are composed of a complex of several distinct genetic types that may correspond to cryptic or pseudo-cryptic species. These genetic types are usually delimitated using partial sequences located at the 3'end of the SSUrDNA, but typically based on empirical delimitation. Here, we first use patristic genetic distances calculated within and among genetic types of the most common morpho-species to show that intra-type and inter-type genetic distances within morpho-species may significantly overlap, suggesting that genetic types have been sometimes inconsistently defined. We further apply two quantitative and independent methods, ABGD (Automatic Barcode Gap Detection and GMYC (General Mixed Yule Coalescent to a dataset of published and newly obtained partial SSU rDNA for a more objective assessment of the species status of these genetic types. Results of these complementary approaches are highly congruent and lead to a molecular taxonomy that ranks 49 genetic types of planktonic foraminifera as genuine (pseudocryptic species. Our results advocate for a standardized sequencing procedure allowing homogenous delimitations of (pseudocryptic species. On the ground of this revised taxonomic framework, we finally provide an integrative taxonomy synthesizing geographic, ecological and morphological differentiations that can occur among the genuine (pseudocryptic species. Due to molecular, environmental or morphological data scarcities, many aspects of our proposed integrative taxonomy are not yet fully resolved. On the other hand, our study opens up the potential for a correct interpretation of environmental sequence datasets.

  14. SSU rDNA divergence in planktonic foraminifera: molecular taxonomy and biogeographic implications.

    Science.gov (United States)

    André, Aurore; Quillévéré, Frédéric; Morard, Raphaël; Ujiié, Yurika; Escarguel, Gilles; de Vargas, Colomban; de Garidel-Thoron, Thibault; Douady, Christophe J

    2014-01-01

    The use of planktonic foraminifera in paleoceanography requires taxonomic consistency and precise assessment of the species biogeography. Yet, ribosomal small subunit (SSUr) DNA analyses have revealed that most of the modern morpho-species of planktonic foraminifera are composed of a complex of several distinct genetic types that may correspond to cryptic or pseudo-cryptic species. These genetic types are usually delimitated using partial sequences located at the 3'end of the SSUrDNA, but typically based on empirical delimitation. Here, we first use patristic genetic distances calculated within and among genetic types of the most common morpho-species to show that intra-type and inter-type genetic distances within morpho-species may significantly overlap, suggesting that genetic types have been sometimes inconsistently defined. We further apply two quantitative and independent methods, ABGD (Automatic Barcode Gap Detection) and GMYC (General Mixed Yule Coalescent) to a dataset of published and newly obtained partial SSU rDNA for a more objective assessment of the species status of these genetic types. Results of these complementary approaches are highly congruent and lead to a molecular taxonomy that ranks 49 genetic types of planktonic foraminifera as genuine (pseudo)cryptic species. Our results advocate for a standardized sequencing procedure allowing homogenous delimitations of (pseudo)cryptic species. On the ground of this revised taxonomic framework, we finally provide an integrative taxonomy synthesizing geographic, ecological and morphological differentiations that can occur among the genuine (pseudo)cryptic species. Due to molecular, environmental or morphological data scarcities, many aspects of our proposed integrative taxonomy are not yet fully resolved. On the other hand, our study opens up the potential for a correct interpretation of environmental sequence datasets.

  15. Variations in phytodetritus derived carbon uptake of the intertidal foraminifera Ammonia tepida and Haynesina germanica

    Science.gov (United States)

    Wukovits, Julia; Bukenberger, Patrick; Enge, Annekatrin; Wanek, Wolfgang; Watzka, Margarete; Heinz, Petra

    2016-04-01

    Phytodetritus represents a major component of particulate organic carbon in intertidal mudflats. Estuaries and tidal currents yield an extensive amount of these particles that display a substantial nutrient source for littoral food webs. For benthic foraminifera, a group of marine protists, phytodetritus serves as the main food source. Foraminifera are considered to play a significant role in marine carbon turnover processes and show seasonally very high population densities in intertidal sediments. Therefore, it is important to gather explicit data about the specific carbon uptake behavior of intertidal foraminiferal species. In this study, laboratory feeding experiments were carried out to observe phytodetrital carbon uptake of foraminiferal specimen collected in the German Wadden Sea. Artificially produced phytodetritus was labelled with 13C to follow carbon ingestion into foraminiferal cytoplasm over time at different simulated conditions. The experiments were performed with monocultures under exclusion of other meiofauna. Chlorophyte detritus (Dunaliella tertiolecta) was fed to the two common species Ammonia tepida and Haynesina germanica. Ammonia tepida showed a significantly higher affinity to this food source than H. germanica. Testing the effect of temperature revealed a significant decrease of carbon ingestion with increasing temperature in H. germanica. Observations focusing on A. tepida showed a rising phytodetrital carbon content in the biomass of juvenile individuals in contrast to adult foraminifera. In general, carbon uptake reaches saturation levels a few hours after food supply. Furthermore, A. tepida benefits from constant availability of fresh food rather than from a high amount of phytodetritus derived from a single food pulse. Our investigations showed that the foraminiferal impact on intertidal processing of phytodetrital carbon sources is species specific, temperature related and depends on developmental stage and input dynamics

  16. Planktonic foraminifera-derived environmental DNA extracted from abyssal sediments preserves patterns of plankton macroecology

    Science.gov (United States)

    Morard, Raphaël; Lejzerowicz, Franck; Darling, Kate F.; Lecroq-Bennet, Béatrice; Winther Pedersen, Mikkel; Orlando, Ludovic; Pawlowski, Jan; Mulitza, Stefan; de Vargas, Colomban; Kucera, Michal

    2017-06-01

    Deep-sea sediments constitute a unique archive of ocean change, fueled by a permanent rain of mineral and organic remains from the surface ocean. Until now, paleo-ecological analyses of this archive have been mostly based on information from taxa leaving fossils. In theory, environmental DNA (eDNA) in the sediment has the potential to provide information on non-fossilized taxa, allowing more comprehensive interpretations of the fossil record. Yet, the process controlling the transport and deposition of eDNA onto the sediment and the extent to which it preserves the features of past oceanic biota remains unknown. Planktonic foraminifera are the ideal taxa to allow an assessment of the eDNA signal modification during deposition because their fossils are well preserved in the sediment and their morphological taxonomy is documented by DNA barcodes. Specifically, we re-analyze foraminiferal-specific metabarcodes from 31 deep-sea sediment samples, which were shown to contain a small fraction of sequences from planktonic foraminifera. We confirm that the largest portion of the metabarcode originates from benthic bottom-dwelling foraminifera, representing the in situ community, but a small portion (DNA is preserved in a range of marine sediment types, the composition of the recovered eDNA metabarcode is replicable and that both the similarity structure and the diversity pattern are preserved. Our results suggest that sedimentary eDNA could preserve the ecological structure of the entire pelagic community, including non-fossilized taxa, thus opening new avenues for paleoceanographic and paleoecological studies.

  17. 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

  18. Detecting Symbioses in Complex Communities: the Fungal Symbionts of Bark and Ambrosia Beetles Within Asian Pines.

    Science.gov (United States)

    Skelton, James; Jusino, Michelle A; Li, You; Bateman, Craig; Thai, Pham Hong; Wu, Chengxu; Lindner, Daniel L; Hulcr, Jiri

    2018-02-24

    Separating symbioses from incidental associations is a major obstacle in symbiosis research. In this survey of fungi associated with Asian bark and ambrosia beetles, we used quantitative culture and DNA barcode identification to characterize fungal communities associated with co-infesting beetle species in pines (Pinus) of China and Vietnam. To quantitatively discern likely symbioses from coincidental associations, we used multivariate analysis and multilevel pattern analysis (a type of indicator species analysis). Nearly half of the variation in fungal community composition in beetle galleries and on beetle bodies was explained by beetle species. We inferred a spectrum of ecological strategies among beetle-associated fungi: from generalist multispecies associates to highly specialized single-host symbionts that were consistently dominant within the mycangia of their hosts. Statistically significant fungal associates of ambrosia beetles were typically only found with one beetle species. In contrast, bark beetle-associated fungi were often associated with multiple beetle species. Ambrosia beetles and their galleries were frequently colonized by low-prevalence ambrosia fungi, suggesting that facultative ambrosial associations are commonplace, and ecological mechanisms such as specialization and competition may be important in these dynamic associations. The approach used here could effectively delimit symbiotic interactions in any system where symbioses are obscured by frequent incidental associations. It has multiple advantages including (1) powerful statistical tests for non-random associations among potential symbionts, (2) simultaneous evaluation of multiple co-occurring host and symbiont associations, and (3) identifying symbionts that are significantly associated with multiple host species.

  19. 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.

  20. Horizontal transmission of the insect symbiont Rickettsia is plant-mediated

    Science.gov (United States)

    Caspi-Fluger, Ayelet; Inbar, Moshe; Mozes-Daube, Netta; Katzir, Nurit; Portnoy, Vitaly; Belausov, Eduard; Hunter, Martha S.; Zchori-Fein, Einat

    2012-01-01

    Bacteria in the genus Rickettsia, best known as vertebrate pathogens vectored by blood-feeding arthropods, can also be found in phytophagous insects. The presence of closely related bacterial symbionts in evolutionarily distant arthropod hosts presupposes a means of horizontal transmission, but no mechanism for this transmission has been described. Using a combination of experiments with live insects, molecular analyses and microscopy, we found that Rickettsia were transferred from an insect host (the whitefly Bemisia tabaci) to a plant, moved inside the phloem, and could be acquired by other whiteflies. In one experiment, Rickettsia was transferred from the whitefly host to leaves of cotton, basil and black nightshade, where the bacteria were restricted to the phloem cells of the plant. In another experiment, Rickettsia-free adult whiteflies, physically segregated but sharing a cotton leaf with Rickettsia-plus individuals, acquired the Rickettsia at a high rate. Plants can serve as a reservoir for horizontal transmission of Rickettsia, a mechanism which may explain the occurrence of phylogenetically similar symbionts among unrelated phytophagous insect species. This plant-mediated transmission route may also exist in other insect–symbiont systems and, since symbionts may play a critical role in the ecology and evolution of their hosts, serve as an immediate and powerful tool for accelerated evolution. PMID:22113034

  1. 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.

  2. Sphingolipid Metabolism of a Sea Anemone Is Altered by the Presence of Dinoflagellate Symbionts.

    Science.gov (United States)

    Kitchen, Sheila A; Poole, Angela Z; Weis, Virginia M

    2017-12-01

    In host-microbe interactions, signaling lipids function in interpartner communication during both the establishment and maintenance of associations. Previous evidence suggests that sphingolipids play a role in the mutualistic cnidarian-Symbiodinium symbiosis. Exogenously applied sphingolipids have been shown to alter this partnership, though endogenous host regulation of sphingolipids by the sphingosine rheostat under different symbiotic conditions has not been characterized. The rheostat regulates levels of pro-survival sphingosine-1-phosphate (S1P) and pro-apoptotic sphingosine (Sph) through catalytic activities of sphingosine kinase (SPHK) and S1P phosphatase (SGPP). The role of the rheostat in recognition and establishment of cnidarian-Symbiodinium symbiosis was investigated in the sea anemone Aiptasia pallida by measuring gene expression, protein levels, and sphingolipid metabolites in symbiotic, aposymbiotic, and newly recolonized anemones. Comparison of two host populations showed that symbiotic animals from one population had lower SGPP gene expression and Sph lipid concentrations compared to aposymbiotic animals, while the other population had higher S1P concentrations than their aposymbiotic counterparts. In both populations, the host rheostat trended toward host cell survival in the presence of symbionts. Furthermore, upregulation of both rheostat enzymes on the first day of host recolonization by symbionts suggests a role for the rheostat in host-symbiont recognition during symbiosis onset. Collectively, these data suggest a regulatory role of sphingolipid signaling in cnidarian-Symbiodinium symbiosis and symbiont uptake.

  3. Isolation of symbionts and GC-MS analysis of lichens collected from ...

    African Journals Online (AJOL)

    In Nigeria, a good number of lichen species have been recorded and so far not much work has been done to isolate or identify the symbionts. The utility of lichen comes from a range of secondary compounds produced by them. In view of this, two lichen samples, foliose (Parmalia reticulata Taylor) and fruticose Usnea ...

  4. 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. Copyright © 2014 Elsevier Inc. All rights reserved.

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

    NARCIS (Netherlands)

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

    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

  6. 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.

  7. Parasitoid gene expression changes after adaptation to symbiont-protected hosts.

    Science.gov (United States)

    Dennis, Alice B; Patel, Vilas; Oliver, Kerry M; Vorburger, Christoph

    2017-11-01

    Reciprocal selection between aphids, their protective endosymbionts, and the parasitoid wasps that prey upon them offers an opportunity to study the basis of their coevolution. We investigated adaptation to symbiont-conferred defense by rearing the parasitoid wasp Lysiphlebus fabarum on aphids (Aphis fabae) possessing different defensive symbiont strains (Hamiltonella defensa). After ten generations of experimental evolution, wasps showed increased abilities to parasitize aphids possessing the H. defensa strain they evolved with, but not aphids possessing the other strain. We show that the two symbiont strains encode different toxins, potentially creating different targets for counter-adaptation. Phenotypic and behavioral comparisons suggest that neither life-history traits nor oviposition behavior differed among evolved parasitoid lineages. In contrast, comparative transcriptomics of adult female wasps identified a suite of differentially expressed genes among lineages, even when reared in a common, symbiont-free, aphid host. In concurrence with the specificity of each parasitoid lineages' infectivity, most differentially expressed parasitoid transcripts were also lineage-specific. These transcripts are enriched with putative venom toxins and contain highly expressed, potentially defensive viral particles. Together, these results suggest that wild populations of L. fabarum employ a complicated offensive arsenal with sufficient genetic variation for wasps to adapt rapidly and specifically to their hosts' microbial defenses. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  8. 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

  9. 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 symbiosi...

  10. 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.

  11. 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…

  12. Gastrointestinal symbionts of chimpanzees in Cantanhez National Park, Guinea-Bissau with respect to habitat fragmentation

    Czech Academy of Sciences Publication Activity Database

    Sá, R. M.; Petrášová, J.; Pomajbíková, K.; Profousová, I.; Petrželková, Klára Judita; Sousa, C.; Cable, J.; Bruford, M. W.; Modrý, David

    2013-01-01

    Roč. 75, č. 10 (2013), s. 1032-1041 ISSN 0275-2565 Institutional support: RVO:68081766 ; RVO:60077344 Keywords : Cantanhez National Park * fragmentation * Pan troglodytes verus * parasites * symbionts * Trichuris sp Subject RIV: EG - Zoology Impact factor: 2.136, year: 2013

  13. Ultra-precision bearings

    CERN Document Server

    Wardle, F

    2015-01-01

    Ultra-precision bearings can achieve extreme accuracy of rotation, making them ideal for use in numerous applications across a variety of fields, including hard disk drives, roundness measuring machines and optical scanners. Ultraprecision Bearings provides a detailed review of the different types of bearing and their properties, as well as an analysis of the factors that influence motion error, stiffness and damping. Following an introduction to basic principles of motion error, each chapter of the book is then devoted to the basic principles and properties of a specific type of bearin

  14. 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.

  15. Preferential allocation, physio-evolutionary feedbacks, and the stability and environmental patterns of mutualism between plants and their root symbionts.

    Science.gov (United States)

    Bever, James D

    2015-03-01

    The common occurrence of mutualistic interactions between plants and root symbionts is problematic. As the delivery of benefit to hosts involves costs to symbionts, symbionts that provide reduced benefit to their host are expected to increase in frequency. Plants have been shown to allocate preferentially to the most efficient symbiont and this preferential allocation may stabilize the mutualism. I construct a general model of the interactive feedbacks of host preferential allocation and the dynamics of root symbiont populations to evaluate the stability of nutritional mutualisms. Preferential allocation can promote the evolution of mutualism even when the cost to the symbiont is very large. Moreover, the physiological plasticity of preferential allocation likely leads to coexistence of beneficial and nonbeneficial symbionts. For arbuscular mycorrhizal fungi, which facilitate plant uptake of phosphorus (P), the model predicts greater P transfer from these fungi per unit carbon invested with decreasing concentrations of soil P and with increasing concentrations of atmospheric CO2 , patterns that have been observed in laboratory and field studies. This framework connects physiological plasticity in plant allocation to population processes that determine mutualism stability and, as such, represents a significant step in understanding the stability and environmental patterns in mutualism. © 2015 The Author. New Phytologist © 2015 New Phytologist Trust.

  16. Miocene benthic foraminifera from Nosy Makamby and Amparafaka, Mahajanga Basin, northwestern Madagascar

    Science.gov (United States)

    Ramihangihajason, Tolotra N.; Andrianavalona, Tsiory H.; Razafimbelo, Rachel; Rahantarisoa, Lydia; Ali, Jason R.; Samonds, Karen E.

    2014-12-01

    Madagascar is well known for its fossil deposits and hosts one of the world's most important Upper Cretaceous terrestrial faunal sites (in the Mahajanga and Morondava Basins in the west and northwest of the island). Cenozoic marine fossils are also described from Madagascar, but these have received far less attention from the paleontological community, with most of this work dating from the 19th and early 20th centuries. Our study reports a new comprehensive microfossil assemblage from a Miocene sequence on the island of Nosy Makamby. After washing, sieving and sorting (∼30 kg), twenty-five genera of foraminifera were identified including Alveolina, Ammodiscus, Ammonia, Archaias, Bolivina, Borelis, Cassidulina, Cyclammina, Cycloforina, Dentalina, Elphidium, Hauerina, Lagena, Lepidocyclina, Nodosaria, Nonion, Nonionella, Peneroplis, Pyrgo, Quinqueloculina, Rhabdammina, Spirillina, Spirolina, Spiroloculina and Triloculina. Ostracods are found in association with the foraminifera, as well as many other macroinvertebrate fossils (including bivalves, gastropods, and echinoids) in addition to vertebrate fossils. Together, the assemblage indicates that during the late Miocene, Nosy Makamby was a tropical, near-shore environment, probably similar to that seen today. Furthermore, the existence of epiphytic foraminiferans (e.g., Elphidium) suggests that sea-grass beds were likely present.

  17. Diagenetic alteration of benthic foraminifera from a methane seep site on Vestnesa Ridge (NW Svalbard)

    Science.gov (United States)

    Schneider, Andrea; Crémière, Antoine; Panieri, Giuliana; Lepland, Aivo; Knies, Jochen

    2017-05-01

    Anomalously low δ13C values in foraminiferal calcite tests are due to diagenetic alteration in methane seep sites. Our study applies diagenetically altered fossil benthic foraminiferal tests as geochemical tracers in reconstructing natural past methane seepage episodes at Vestnesa Ridge offshore NW Svalbard. We combine examinations of the test wall microstructure, mineralogical and stable carbon isotope composition of foraminifera and co-occurring authigenic carbonate nodules. We present a classification of visual and mineralogical characteristics of the exterior and interior test wall microstructure of the benthic foraminiferal species Cassidulina neoteretis having experienced different degrees of diagenetic alteration during methane seepage. Carbonate nodules comprising high-Mg calcite cement with 13-15 mol% MgCO3 have δ13C values as low as -32.3‰, which is consistent with a methane-derived origin. The visual, mineralogical and stable isotope investigations of C. neoteretis indicate a variable degree of diagenetic alteration and show δ13C values between -0.6 and -16.9‰. The negative δ13C values in benthic foraminifera are largely caused by precipitation of isotopically light methane-derived authigenic carbonate as high-Mg-calcite coatings, whose relative contribution to the bulk foraminiferal carbonate is estimated to be up to 58 wt%. Another key finding is the identification of the first seepage episode concurrent with Heinrich Event 1 (HE 1), and a second seepage episode at the onset of the Bølling-Allerød Interstadial.

  18. Parasitoids and dipteran predators exploit volatiles from microbial symbionts to locate bark beetles.

    Science.gov (United States)

    Boone, Celia K; Six, Diana L; Zheng, Yanbing; Raffa, Kenneth F

    2008-02-01

    Host location by parasitoids and dipteran predators of bark beetles is poorly understood. Unlike coleopteran predators that locate prey by orienting to prey pheromones, wasps and flies often attack life stages not present until after pheromone production ceases. Bark beetles have important microbial symbionts, which could provide sources of cues. We tested host trees, trees colonized by beetles and symbionts, and trees colonized by symbionts alone for attractiveness to hymenopteran parasitoids and dipteran predators. Field studies were conducted with Ips pini in Montana. Three pteromalid wasps were predominant. All were associated with the second and third instars of I. pini. Heydenia unica was more attracted to logs colonized by either I. pini or the fungus Ophiostoma ips than logs alone or blank controls (screen with no log). Rhopalicus pulchripennis was more attracted to logs colonized by I. pini than logs alone or blank controls. Dibrachys cavus was attracted to logs but did not distinguish whether or not they were colonized. Two dolichopodid predators were predominant. A Medetera species was more attracted to colonized than uncolonized logs and more attracted to logs than blank controls. It was also more attracted to logs colonized with the yeast Pichia scolyti than uncolonized logs, but attraction was less consistent. An unidentified dolichopodid was more attracted to logs colonized with I. pini, O. ips, and the bacteria Burkholderia sp., than to uncolonized logs. It was also attracted to uncolonized logs. Its responses were less consistent and pronounced than H. unica. These results suggest some parasitoids and dipteran predators exploit microbial symbionts of bark beetles to locate hosts. Overall, specialists showed strong attraction to fungal cues, whereas generalists were more attracted by plant volatiles. These results also show how microbial symbionts can have conflicting effects on host fitness.

  19. Root fungal symbionts interact with mammalian herbivory, soil nutrient availability and specific habitat conditions.

    Science.gov (United States)

    Ruotsalainen, Anna L; Eskelinen, Anu

    2011-07-01

    Herbivory, competition and soil fertility interactively shape plant communities and exhibit an important role in modifying conditions for host-dependent fungal symbionts. However, field studies on the combined impacts of natural herbivory, competition and soil fertility on root fungal symbionts are rare. We asked how mammalian herbivory, fertilization, liming and plant-plant competition affect the root colonization of arbuscular mycorrhizal fungi (AMF) and dark septate endophytic (DSE) fungi of the dicot herb, Solidago virgaurea. The 2-year full-factorial experiment was conducted in two contrasting habitats: non-acidic and acidic mountain tundra. We found that herbivory increased arbuscular colonization (i.e. the site of resource exchange) at fertile non-acidic sites, where vegetation was rich in species having AMF symbionts, whereas at infertile acidic sites, where plants having AMF symbiont are scarce, the response was the opposite. Herbivory of the host plant negatively affected DSE hyphal and sclerotial colonization in unfertilized plots, possibly due to reduced carbon flow from the host plant while there was no effect of herbivory in fertilized plots. DSE colonization was highest in unfertilized exclosures where soil nutrient concentrations were also lowest. Liming had a negative effect on DSE hyphal colonization, and its effect also interacted with herbivory and the habitat. Biomass removal of the neighboring plants did not affect the root colonization percent of either arbuscules or DSE. Our results show that the impacts of aboveground mammalian herbivory, soil nutrient availability and specific habitat conditions on belowground root fungal symbionts are highly dependent on each other. Arbuscule response to herbivory appeared to be regulated by specific habitat conditions possibly caused by differences in the AMF availability in the soil while DSE response was associated with availability of host-derived carbon. Our result of the relationship between

  20. Evolution and function of eukaryotic-like proteins from sponge symbionts.

    Science.gov (United States)

    Reynolds, David; Thomas, Torsten

    2016-10-01

    Sponges (Porifera) are ancient metazoans that harbour diverse microorganisms, whose symbiotic interactions are essential for the host's health and function. Although symbiosis between bacteria and sponges are ubiquitous, the molecular mechanisms that control these associations are largely unknown. Recent (meta-) genomic analyses discovered an abundance of genes encoding for eukaryotic-like proteins (ELPs) in bacterial symbionts from different sponge species. ELPs belonging to the ankyrin repeat (AR) class from a bacterial symbiont of the sponge Cymbastela concentrica were subsequently found to modulate amoebal phagocytosis. This might be a molecular mechanism, by which symbionts can control their interaction with the sponge. In this study, we investigated the evolution and function of ELPs from other classes and from symbionts found in other sponges to better understand the importance of ELPs for bacteria-eukaryote interactions. Phylogenetic analyses showed that all of the nine ELPs investigated were most closely related to proteins found either in eukaryotes or in bacteria that can live in association with eukaryotes. ELPs were then recombinantly expressed in Escherichia coli and exposed to the amoeba Acanthamoeba castellanii, which is functionally analogous to phagocytic cells in sponges. Phagocytosis assays with E. coli containing three ELP classes (AR, TPR-SEL1 and NHL) showed a significantly higher percentage of amoeba containing bacteria and average number of intracellular bacteria per amoeba when compared to negative controls. The result that various classes of ELPs found in symbionts of different sponges can modulate phagocytosis indicates that they have a broader function in mediating bacteria-sponge interactions. © 2016 John Wiley & Sons Ltd.

  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. Investigation of Bearing Technology

    National Research Council Canada - National Science Library

    Maciag, Walter

    1998-01-01

    .... They eliminate roller needles and balls in bearings. Since the GC design does not require lubrication maintenance, there is no need for the u-joint cross to contain lubrication reservoirs and distribution channels and their input fitting...

  3. DW_BEAR

    Data.gov (United States)

    Department of Homeland Security — Subset of BEAR (Bi-Weekly Examination Analysis and Reporting) data used for financial audit remediation reporting within the Coast Guard Business Intelligence (CGBI)...

  4. Gear bearing drive

    Science.gov (United States)

    Weinberg, Brian (Inventor); Mavroidis, Constantinos (Inventor); Vranish, John M. (Inventor)

    2011-01-01

    A gear bearing drive provides a compact mechanism that operates as an actuator providing torque and as a joint providing support. The drive includes a gear arrangement integrating an external rotor DC motor within a sun gear. Locking surfaces maintain the components of the drive in alignment and provide support for axial loads and moments. The gear bearing drive has a variety of applications, including as a joint in robotic arms and prosthetic limbs.

  5. Rolling bearing analysis

    CERN Document Server

    Harris, Tedric A

    2001-01-01

    One of the most well-known experts in the field brings cutting-edge research to practitioners in the new edition of this important reference. Covers the improved mathematical calculations for rolling bearing endurance developed by the American Society of Mechanical Engineers and the Society of Lubrication and Tribology Engineers. Updated with new material on Condition-Based Maintenance, new testing methods, and new bearing materials.

  6. Load responsive hydrodynamic bearing

    Science.gov (United States)

    Kalsi, Manmohan S.; Somogyi, Dezso; Dietle, Lannie L.

    2002-01-01

    A load responsive hydrodynamic bearing is provided in the form of a thrust bearing or journal bearing for supporting, guiding and lubricating a relatively rotatable member to minimize wear thereof responsive to relative rotation under severe load. In the space between spaced relatively rotatable members and in the presence of a liquid or grease lubricant, one or more continuous ring shaped integral generally circular bearing bodies each define at least one dynamic surface and a plurality of support regions. Each of the support regions defines a static surface which is oriented in generally opposed relation with the dynamic surface for contact with one of the relatively rotatable members. A plurality of flexing regions are defined by the generally circular body of the bearing and are integral with and located between adjacent support regions. Each of the flexing regions has a first beam-like element being connected by an integral flexible hinge with one of the support regions and a second beam-like element having an integral flexible hinge connection with an adjacent support region. A least one local weakening geometry of the flexing region is located intermediate the first and second beam-like elements. In response to application of load from one of the relatively rotatable elements to the bearing, the beam-like elements and the local weakening geometry become flexed, causing the dynamic surface to deform and establish a hydrodynamic geometry for wedging lubricant into the dynamic interface.

  7. Late cretaceous foraminifera, paleoenvironments, and paleoceanography of the rosario formation, San Antonio del Mar, Baja California, Mexico

    Science.gov (United States)

    Maestas, Y.; MacLeod, K.G.; Douglas, R.; Self-Trail, J.; Ward, P.D.

    2003-01-01

    The 315 m of Rosario Formation exposed at the San Antonio del Mar (SADM) section (Baja California, Mexico) contains moderately-to-well preserved benthic and planktic foraminifera, calcareous nannofossils, and molluscs. Nannofossils suggest most of the SADM section was deposited within a narrow interval of the late Campanian (CC21-CC22), whereas foraminifera and molluscs suggest a younger maximum age (younger than the Globotruncana ventricosa Zone) and allow deposition over a longer interval of time. Planktic foraminifera at SADM represent common Tethyan taxa. They are largely restricted to the lower and middle portions of the section and comprise 0-???40% of foraminiferal assemblages. Stable isotopic analyses of Rugoglobigerina rugosa yield ??18OV-PDB values from -2.27%, to -2.82%, corresponding to salinity-corrected paleotemperature estimates of 26-30??C for the Late Cretaceous eastern Pacific. These estimates are as warm as modern tropical temperatures and are similar to tropical paleotemperature estimates from ??18O analyses of exceptionally preserved Maastrichtian samples; however, they are considerably warmer than most tropical Campanian-Maastrichtian estimates. Benthic foraminifera indicate outer shelf paleodepths with a slight increase in depth or decrease in benthic oxygen levels in the upper parts of the interval studied. The change in the benthic assemblage corresponds to an ???1??? positive shift in benthic ??O18, suggesting a relationship between benthic assemblages and an inferred increase in the local intensity of upwelling.

  8. Effects of radionuclides on the recent foraminifera from the clastic sediments of the Çanakkale Strait-Turkey

    Science.gov (United States)

    Yümün, Zeki Ünal; Kam, Erol

    2017-07-01

    The radionuclides that cause radioactivity accumulate in the sediments as they descend to the seabed, similar to heavy metals. As radionuclides are present on the surface of the sediment or within the sediment, marine benthic foraminifera can be affected by the radioactive pollution. In this study, the habitat of benthic foraminifera was evaluated for radioactive pollution in the Çanakkale Strait, which constitutes the passage of the Marmara Sea and the Aegean Sea. In 2015, seven core samples and one drilling sample were taken from the shallow marine environment, which is the habitat of benthic foraminifera, in the Çanakkale Strait. Locations of the core samples were specifically selected to be pollution indicators in port areas. Gamma spectrometric analysis was used to determine the radioactivity properties of sediments. The radionuclide concentration activity values in the sediment samples obtained from the locations were Cs-137: pollution. Although the Ra-226 values obtained in the study areas remained within normal limits according to UNSCEAR values, the K-40 and Th-232 series values were observed to be high in almost all locations. The values of Cs-137 were found to be maximum 20 in Çanakkale Dere Port and they were parallel to the values in the other places. In the study, 13 genera and 20 species were identified from core and drilling samples. The number of foraminifera species and individuals obtained at locations with high pollution was very low compared to those in non-polluted zones.

  9. Seaweed fails to prevent ocean acidification impact on foraminifera along a shallow-water CO2 gradient.

    Science.gov (United States)

    Pettit, Laura R; Smart, Christopher W; Hart, Malcolm B; Milazzo, Marco; Hall-Spencer, Jason M

    2015-05-01

    Ocean acidification causes biodiversity loss, alters ecosystems, and may impact food security, as shells of small organisms dissolve easily in corrosive waters. There is a suggestion that photosynthetic organisms could mitigate ocean acidification on a local scale, through seagrass protection or seaweed cultivation, as net ecosystem organic production raises the saturation state of calcium carbonate making seawater less corrosive. Here, we used a natural gradient in calcium carbonate saturation, caused by shallow-water CO2 seeps in the Mediterranean Sea, to assess whether seaweed that is resistant to acidification (Padina pavonica) could prevent adverse effects of acidification on epiphytic foraminifera. We found a reduction in the number of species of foraminifera as calcium carbonate saturation state fell and that the assemblage shifted from one dominated by calcareous species at reference sites (pH ∼8.19) to one dominated by agglutinated foraminifera at elevated levels of CO2 (pH ∼7.71). It is expected that ocean acidification will result in changes in foraminiferal assemblage composition and agglutinated forms may become more prevalent. Although Padina did not prevent adverse effects of ocean acidification, high biomass stands of seagrass or seaweed farms might be more successful in protecting epiphytic foraminifera.

  10. Marine connections of Amazonia: Evidence from foraminifera and dinoflagellate cysts (early to middle Miocene, Colombia/Peru)

    NARCIS (Netherlands)

    Boonstra, M.; Ramos, M.I.F.; Lammertsma, E.I.; Antoine, P.-O; Hoorn, C.

    2015-01-01

    Species composition in the present-day Amazonian heartland has an imprint of past marine influence. The exact nature, timing and extent of this marine influence, however, are largely unresolved. Here we use calcareous tests of foraminifera and marine palynomorphs from Miocene sediments in

  11. Deep sea benthic foraminifera as a proxy of methane hydrates from IODP site 890B Cascadia Margin

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A. [Ministry of Petroleum, Noida (India). National Gas Hydrates Program; Gupta, A.K. [Indian Inst. of Technology, Kharagpur (India). Dept of Geology and Geophysics

    2008-07-01

    The release of methane from marine reservoirs of methane hydrates into the atmosphere has been linked to climate change through variations in benthic foraminifera signatures. This paper investigated deep sea benthic foraminifera from 174 samples taken from the north Pacific Ocean near the Cascadia Margin. The aim of the study was to develop a better understanding of benthic foraminiferal distribution in the methane-rich environment of the Cascadia Margin. Benthic foraminifera are good indicators of paleoproductivity in areas where carbon fluxes are high. Factor and cluster analyses were used to identify 6 biofacies. Ecological data from recent deep sea benthic foraminifera were used to characterize the biofacies. A benthic faunal record was used to determine oxygenation, surface productivity, and organic food supplies. Results of the study indicated that benthic assemblages showed a major shift at 2 to 3 K yrs BP and 6 to 10.5 BP coincided with the increasing amplitude of interstadial cycles, in which methane fluxes may have played a significant role. It was concluded that the dissociation of gas hydrates and the release of methane into the atmosphere may have caused an increase in the population of highly reducing environmental species.. 55 refs., 1 tab., 3 figs.

  12. Living deep-sea benthic foraminifera from the Cap de Creus Canyon (western Mediterranean): Faunal-geochemical interactions

    NARCIS (Netherlands)

    Contreras-Rosales, L.A.; Koho, K.A.; Duijnstee, I.A.P.; de Stigter, H.C.; García, R.; Koning, E.; Epping, E.

    2012-01-01

    Rose-Bengal-stained benthic foraminifera were sampled along a depth transect from the Cap de Creus Canyon and the adjacent slope. Well-stained individuals were studied in the top 5 cm of sediment and the faunal abundances and assemblages were compared against pore-water geochemistry and biochemical

  13. Recent benthic foraminifera and sedimentary facies from mangrove swamps and channels of Abu Dhabi (United Arab Emirates)

    Science.gov (United States)

    Fiorini, Flavia; Odeh, Weaam A. S. Al; Lokier, Stephen W.; Paul, Andreas

    2016-04-01

    Zonation of Recent mangrove environments can be defined using benthic foraminifera, however, little is known about foraminifera from mangrove environments of the Arabian Gulf. The objective of this study is to produce a detailed micropaleontological and sedimentological analysis to identify foraminiferal associations in several coastline environments (mangrove swamps and channels) located on the eastern side of Abu Dhabi Island (UAE). Detailed sediment sampling collection in mangal environments of Eastern Abu Dhabi was carried out to assess the distribution of living and dead benthic foraminifera in different sedimentary facies in the mangal and in the surrounding area comprising natural environments of the upper and lower intertidal area (mud flats and channels) and areas modified by anthropogenic activities (dredged channels). The fine-grain sediments collected near mangrove (Avicenna marina) roots presented a high abundance of living and dead foraminifera tests. The assemblages in these samples show very low diversity and are almost entirely constituted of small-sized opportunistic species belonging to the genera Ammonia and Elphidium. In particular: • Samples collected on the mud flat and in ponds at the margin of the channel show a foraminiferal assemblage characterised by abundant foraminifera belonging to the genera Ammonia, Elphidium, Triloculina, Quinqueloculina, Peneroplis and Spirolina. • Samples collected in the lower (wet) intertidal area close to Avicenna marina roots, presented a low-diversity assemblage mostly comprising opportunistic foraminifera of the genera Ammonia and Elphidium along with rare miliolidae. • Samples from the upper intertidal area (dry) close to Avicenna marina roots, produced an assemblage exclusively composed of small-sized opportunistic Ammonia and Elphidium, together with abundant specimens belonging to the genera Trochammina. Throchammina specimens have not been previously recorded from Recent sedimentary samples of

  14. Watchable Wildlife: The Black Bear

    Science.gov (United States)

    Lynn L. Rogers

    1992-01-01

    Black bears are the bears people most often encounter. Black bears live in forests over much of North America, unlike grizzlies that live only in Alaska, northern and western Canada, and the northern Rocky Mountains. This brochure presents the latest information on black bear life and how this species responds to an ever-increasing number of campers, hikers, and...

  15. Climate Drives Polar Bear Origins

    Science.gov (United States)

    In their provocative analysis of northern bears (“Nuclear genomic sequences reveal that polar bears are an old and distinct bear lineage,” Reports, 20 April, p. 344), F. Hailer et al. use independent nuclear loci to show that polar bears originated during the middle Pleistocene, rather than during t...

  16. Intertidal foraminifera (Protista) and carbon-nitrogen cycling: combined effects of temperature and diet quality

    Science.gov (United States)

    Wukovits, Julia; Enge, Annekatrin Julie; Oberrauch, Max; Watzka, Margarete; Wanek, Wolfgang; Heinz, Petra

    2017-04-01

    Benthic foraminifera (eukaryotic protists) are to a large extent acting as detrivores, feeding on microalgal detritus. Phytodetritus constitutes a main component of the intertidal carbon (C) and nitrogen (N) pool, thus making foraminifera important players in intertidal nutrient fluxes. These fluxes are strongly dependent on interactions between biotic and abiotic environmental factors, as e.g. the energetic value or the quality of phytodetritus that depends on environmental nutrient availability. Increased inorganic C concentrations in coastal water bodies (e.g. due to increased atmospheric CO2) can have a negative effect on the phytodetrital quality by increasing microalgal C:N ratios. Simultanous warming of the environment can cause increased metabolic rates of exposed heterotrophic organisms, like foraminifera. The combination of lower food quality and increased metabolic rates is supposed to cause cascading effects on organismic C cycling, potentially diminishing the role of detrivorous food as a C sink in marine food webs by increased discharge of excess C. In this study, the above described scenario was tested in laboratory feeding experiments on a common and abundant intertidal foraminiferal species (Haynesina germanica, collected in the German Wadden Sea). Two batches of artificially produced and dual isotope labeled (13C and 15N) chlorophyte detritus (1.5 gDW m-2) with different C:N ratios (5.5 and 7.6) and one batch of isotopically labelled diatom detritus (C:N 5.6) were fed under controlled conditions at three different temperatures. Results were extrapolated to the in situ abundance of live H. germanica individuals in the sampling area (sediment core data), to estimate the magnitude of the effect on an areal basis within the natural habitat. The study revealed significant, temperature induced variations in the carbon and nitrogen processing of H. germanica. The food source with an increased C:N ratio doubled the release of carbon from the H. germanica

  17. Deep-sea Benthic Foraminifera in the SE Atlantic across Eocene Hyperthermal Events

    Science.gov (United States)

    Thomas, E.

    2016-12-01

    Short-term episodes of global warming (hyperthermal events) were superimposed on the warming trend into the Early Eocene Climate Optimum (EECO). The Paleocene-Eocene Thermal Maximum (PETM; 56 Ma) was the most extreme, followed by Eocene Thermal Maximum-2 and -3 (ETM2: 1.8 myr, ETM3: 3.1 myr post-PETM). Hyperthermals are characterized by negative carbon isotope excursions (CIEs, emission of isotopically light carbon in the ocean-atmosphere), negative oxygen isotope excursions (global warming) and carbonate dissolution (ocean acidification). Sensitivity of biota to environmental changes due to carbon emissions can be evaluated by studying their response to hyperthermals of different magnitude. Deep-sea benthic foraminiferal records across PETM, ETM2 and -3 are available for Site 1262 (3600 m) and 1263 (1500m) on SE Atlantic Walvis Ridge. Benthic foraminifera (carbonate and agglutinated) are absent in the carbonate-free PETM clay-layer (Site 1262: 65 kyr; Site1263: 10 kyr). Deep-sea benthic foraminifera suffered extinction and diversity loss at the start of the PETM, as they did globally, with diversity recovering only partially. Stable isotope records show a larger PETM-CIE and amount of warming at Site 1263 than global average (McCarren et al., 2008), and warming was more pronounced at Site 1263 than at 1262 during ETM2 (Jennions et al., 2015) and ETM3 (Roehl et al., 2005). During ETM2 and -3, carbonate dissolution affected the sites, both remaining between CCD and lysocline. Assemblages were more severely affected (larger drop in benthic foraminiferal accumulation rates, BFAR) at the shallower site, opposite to expected if caused mainly by carbonate corrosivity. The large decrease in BFAR indicates a decline in food arrival at the sea floor, more pronounced at the shallower site, as supported by changes in relative and absolute abundance of species, and more pronounced at ETM2 than at ETM3. Greater warming at intermediate depths could have been caused by ocean

  18. Ontogenetic Changes in the Bacterial Symbiont Community of the Tropical Demosponge Amphimedon queenslandica: Metamorphosis Is a New Beginning

    OpenAIRE

    Fieth, Rebecca A.; Gauthier, Marie-Emilie A.; Bayes, Joanne; Green, Kathryn M.; Degnan, Sandie M.

    2016-01-01

    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 t...

  19. 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

  20. Radial Halbach Magnetic Bearings

    Science.gov (United States)

    Eichenberg, Dennis J.; Gallo, Christopher A.; Thompson, William K.

    2009-01-01

    Radial Halbach magnetic bearings have been investigated as part of an effort to develop increasingly reliable noncontact bearings for future high-speed rotary machines that may be used in such applications as aircraft, industrial, and land-vehicle power systems and in some medical and scientific instrumentation systems. Radial Halbach magnetic bearings are based on the same principle as that of axial Halbach magnetic bearings, differing in geometry as the names of these two types of bearings suggest. Both radial and axial Halbach magnetic bearings are passive in the sense that unlike most other magnetic bearings that have been developed in recent years, they effect stable magnetic levitation without need for complex active control. Axial Halbach magnetic bearings were described in Axial Halbach Magnetic Bearings (LEW-18066-1), NASA Tech Briefs, Vol. 32, No. 7 (July 2008), page 85. In the remainder of this article, the description of the principle of operation from the cited prior article is recapitulated and updated to incorporate the present radial geometry. In simplest terms, the basic principle of levitation in an axial or radial Halbach magnetic bearing is that of the repulsive electromagnetic force between (1) a moving permanent magnet and (2) an electric current induced in a stationary electrical conductor by the motion of the magnetic field. An axial or radial Halbach bearing includes multiple permanent magnets arranged in a Halbach array ("Halbach array" is defined below) in a rotor and multiple conductors in the form of wire coils in a stator, all arranged so the rotary motion produces an axial or radial repulsion that is sufficient to levitate the rotor. A basic Halbach array (see Figure 1) consists of a row of permanent magnets, each oriented so that its magnetic field is at a right angle to that of the adjacent magnet, and the right-angle turns are sequenced so as to maximize the magnitude of the magnetic flux density on one side of the row while

  1. 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

  2. Earliest record of the invasive Foraminifera Trochammina hadai in San Francisco Bay, California, USA

    Science.gov (United States)

    McGann, Mary

    2014-01-01

    In 1995, Trochammina hadai, a benthic Foraminifera prevalent in Japanese estuaries, was found in San Francisco Bay, California, USA. Subsequent field investigations determined that the species was also present in nearly all of the major ports and estuaries along the western United States. Because of its widespread colonization, it is of interest to determine when T. hadai first appeared as an invasive in the coastal regions of the North Pacific. In San Francisco Bay, the species was not found in 404 surface samples collected between 1930 and 1981. In 1983, however, a grab sediment sample from one of four sites in the southern portion of the bay contained T. hadai. This site was the most northern of the four and contained 12 specimens of the invasive, comprising 1.5% of the assemblage. This is the earliest appearance on record of T. hadai in San Francisco Bay.

  3. Sea surface salinity reconstruction as seen with foraminifera shells: Methods and cases studies

    Directory of Open Access Journals (Sweden)

    Malaizé B.

    2009-02-01

    Full Text Available Reconstruction of past salinities in surface oceans (SSS can be done by measuring the isotopic composition of foraminifera shells found in the deep sea sediments. The proportion of heavy oxygen isotopes (18O in the calcite of these shells depend on the temperature and the isotopic oxygen composition of the surrounded waters (δ18 Osw, this latter parameter depending on the water salinity. Mainly two equations allows to reconstructed past SSS, one estimating past temperature variations and the other one changes in the δ18 Osw through time. Uncertainties linked with these calculation can be important, and therefore quantitative reconstructions need to be taken with cautions. For some specific cases, uncertainties on temperature and δ18 Osw estimations can be reduced. For such cases, salinity reconstructions showing amplitude changes higher than 1 per mil can be considered as significative.

  4. Rapid deterioration of sediment surface habitats in Bellingham Bay, Washington State, as indicated by benthic foraminifera.

    Science.gov (United States)

    Nesbitt, Elizabeth A; Martin, Ruth A; Martin, David E; Apple, Jude

    2015-08-15

    Foraminiferal assemblages in sediment grab samples were utilized to evaluate the impacts of anthropogenic activities on benthic habitats in Bellingham Bay, Washington State, U.S.A. Seventy-three samples taken in 1987, 1997, 2006 and 2010 yielded 35 species of foraminifera from 28 genera. Assemblage composition and diversity data indicate a marked deterioration between 1987 and 2010, contrary to the published Chemical Index, but analogous to the situation with macrobiota. Correlation of diversity with chemical pollutants and metals did not identify any significant correlations, however, an unrelated but highly relevant study of bottom water dissolved oxygen concentrations and pH in Bellingham Bay suggests eutrophication with accompanying hypoxia and acidification may be part of the cause. Thus, the metrics of contamination alone do not adequately characterize habitat viability, and benthic foraminiferal assemblages provide insight into the health of coastal ecosystems. Published by Elsevier Ltd.

  5. 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 actinomycete bacterial mutualist (genus Pseudonocardia). Despite the potential of being infected by phylogenetically diverse strains of parasites, each ant colony maintains only a single Pseudonocardia symbiont strain, which is primarily vertically transmitted between colonies by the founding queens....... In this study, we show that Acromyrmex leaf-cutter ants are able to differentiate between their native actinomycete strain and a variety of foreign strains isolated from sympatric and allopatric Acromyrmex species, in addition to strains originating from other fungus-growing ant genera. The recognition...

  6. Rhizobium laguerreae is the main nitrogen-fixing symbiont of cultivated lentil (Lens culinaris) in Morocco.

    Science.gov (United States)

    Taha, Kaoutar; Berraho, El Bekkay; El Attar, Imane; Dekkiche, Samia; Aurag, Jamal; Béna, Gilles

    2018-03-01

    Genetic diversity and population structure of 268 Lens culinaris symbiotic rhizobia collected from 40 cultivated fields in the main lentil production regions in Morocco were estimated. Three chromosomal housekeeping genes (recA, glnII and atpD) and one common symbiotic gene (nodC) were sequenced and analyzed in order to identify the local symbionts of lentil. The molecular phylogeny of the concatenated housekeeping genes clustered more than 95% of the isolates in one main clade together with Rhizobium laguerreae species. R. laguerreae represents the main symbiont of cultivated lentil in Morocco and, for the first time, a large sample of individuals is obtained for this species. There is a significant and high genetic differentiation of bacterial populations among the four regions for their symbiotic gene, and much lower for their housekeeping genes. The reasons why R. laguerreae is so frequently recovered in our study is discussed. Copyright © 2018 Elsevier GmbH. All rights reserved.

  7. 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

    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...

  8. The influence of seawater carbonate ion concentration [CO32-] on the stable carbon isotope composition of the planktic foraminifera species Globorotalia inflata

    NARCIS (Netherlands)

    Wilke, I; Bickert, T.; Peeters, F.J.C.

    2006-01-01

    We sampled the upper water column for living planktic foraminifera along the SW-African continental margin. The species Globorotalia inflata strongly dominates the foraminiferal assemblages with an overall relative abundance of 70-90%. The shell δ

  9. The effect of heavy metal pollution on foraminifera in the Western Marmara Sea (Turkey)

    Science.gov (United States)

    Yümün, Zeki Ünal

    2017-05-01

    The aim of this study was to investigate the effects of heavy metals on foraminiferal assemblages in Holocene sediments in the western Marmara Sea. Accordingly, four drilling samples, one in Bandırma (Balıkesir/Turkey), two in Erdek Bay (Erdek-Bandırma/Turkey) and one in Tekirdağ (Turkey). Samples of cores taken from 43 different locations in the western Marmara Sea also have been examined. Changes in heavy metal concentrations were determined (spatially) in the vertical direction by means of drilling samples in the vertical direction for geochronology and in the horizontal direction by the areal distribution of the core samples, and foraminiferal assemblages were identified. In order to summarize the results of geochemical analyses, an average value defined as Pollution Index (PI) was used for the first time in this study. In this method, the pollution index value is obtained by dividing the sum of average value ratios of heavy metal measurement values by the number of measurements. The obtained index value was correlated separately with the numbers of foraminifer individuals and species. It was observed that the number of individuals and species decreased where the heavy metal measured values (MV) were higher than the pollution index and increased where the heavy metal values were lower than the pollution index. It was also observed that foraminifera were completely absent in some locations where PI was less than MV. Morphological changes were observed in Elphidium crispum, Massilina secans, and Ammonia compacta foraminifer species in the core samples taken in areas where industrial wastes are discharged into the southern parts of the Marmara Sea. No foraminifer species were observed at some locations where the heavy metal density was high (between Misakça-Denizkent, and Erdek-Balikesir). The pollution index (PI) value measured in this area was higher than the critical value, indicating that heavy metal concentrations affect the habitats of foraminifera.

  10. Surviving anoxia in marine sediments: The metabolic response of ubiquitous benthic foraminifera (Ammonia tepida)

    Science.gov (United States)

    Spangenberg, Jorge E.; Mabilleau, Guillaume; Escrig, Stéphane; Meibom, Anders; Geslin, Emmanuelle

    2017-01-01

    High input of organic carbon and/or slowly renewing bottom waters frequently create periods with low dissolved oxygen concentrations on continental shelves and in coastal areas; such events can have strong impacts on benthic ecosystems. Among the meiofauna living in these environments, benthic foraminifera are often the most tolerant to low oxygen levels. Indeed, some species are able to survive complete anoxia for weeks to months. One known mechanism for this, observed in several species, is denitrification. For other species, a state of highly reduced metabolism, essentially a state of dormancy, has been proposed but never demonstrated. Here, we combined a 4 weeks feeding experiment, using 13C-enriched diatom biofilm, with correlated TEM and NanoSIMS imaging, plus bulk analysis of concentration and stable carbon isotopic composition of total organic matter and individual fatty acids, to study metabolic differences in the intertidal species Ammonia tepida exposed to oxic and anoxic conditions. Strongly contrasting cellular-level dynamics of ingestion and transfer of the ingested biofilm components were observed between the two conditions. Under oxic conditions, within a few days, intact diatoms were ingested, degraded, and their components assimilated, in part for biosynthesis of different cellular components: 13C-labeled lipid droplets formed after a few days and were subsequently lost (partially) through respiration. In contrast, in anoxia, fewer diatoms were initially ingested and these were not assimilated or metabolized further, but remained visible within the foraminiferal cytoplasm even after 4 weeks. Under oxic conditions, compound specific 13C analyses showed substantial de novo synthesis by the foraminifera of specific polyunsaturated fatty acids (PUFAs), such as 20:4(n-6). Very limited PUFA synthesis was observed under anoxia. Together, our results show that anoxia induced a greatly reduced rate of heterotrophic metabolism in Ammonia tepida on a time

  11. Can abundance of protists be inferred from sequence data: a case study of foraminifera.

    Directory of Open Access Journals (Sweden)

    Alexandra A-T Weber

    Full Text Available Protists are key players in microbial communities, yet our understanding of their role in ecosystem functioning is seriously impeded by difficulties in identification of protistan species and their quantification. Current microscopy-based methods used for determining the abundance of protists are tedious and often show a low taxonomic resolution. Recent development of next-generation sequencing technologies offered a very powerful tool for studying the richness of protistan communities. Still, the relationship between abundance of species and number of sequences remains subjected to various technical and biological biases. Here, we test the impact of some of these biological biases on sequence abundance of SSU rRNA gene in foraminifera. First, we quantified the rDNA copy number and rRNA expression level of three species of foraminifera by qPCR. Then, we prepared five mock communities with these species, two in equal proportions and three with one species ten times more abundant. The libraries of rDNA and cDNA of the mock communities were constructed, Sanger sequenced and the sequence abundance was calculated. The initial species proportions were compared to the raw sequence proportions as well as to the sequence abundance normalized by rDNA copy number and rRNA expression level per species. Our results showed that without normalization, all sequence data differed significantly from the initial proportions. After normalization, the congruence between the number of sequences and number of specimens was much better. We conclude that without normalization, species abundance determination based on sequence data was not possible because of the effect of biological biases. Nevertheless, by taking into account the variation of rDNA copy number and rRNA expression level we were able to infer species abundance, suggesting that our approach can be successful in controlled conditions.

  12. Arrival and expansion of the invasive foraminifera Trochammina hadai Uchio in Padilla Bay, Washington

    Science.gov (United States)

    McGann, Mary; Grossman, Eric E.; Takesue, Renee K.; Penttila, Dan; Walsh, John P.; Corbett, Reide

    2012-01-01

    Trochammina hadai Uchio, a benthic foraminifera native to Japanese estuaries, was first identified as an invasive in 1995 in San Francisco Bay and later in 16 other west coast estuaries. To investigate the timing of the arrival and expansion of this invasive species in Padilla Bay, Washington, we analyzed the distribution of foraminifera in two surface samples collected in 1971, in nine surface samples collected by Scott in 1972–1973, as well as in two cores (Padilla Flats 3 and Padilla V1/V2) obtained in 2004. Trochanimina hadai, originally identified as the native Trochammina pacifica Cushman in several early foraminiferal studies, dominates the assemblage of most of the surface samples. In the Padilla V1/V2 and Padilla Flats 3 cores, the species' abundance follows a pattern of absence, first appearance, rapid expansion commonly seen shortly after the arrival of a successful biological invasion, setback, and second expansion. Using Q-mode cluster analysis, pre-expansion and expansion assemblages were identified. Pb-210 dating of these cores proved unsuccessful. However, based on T. hadai's first appearance occurring stratigraphically well above sedimentological changes in the cores that reflect deposition of sediments in the bay due to previous diversions of the Skagit River, and its dominance in the early 1970s surface samples, we conclude that the species arrived in Padilla Bay somewhere between the late 1800s and 1971. Trochammina hadai may have been introduced into the bay in the 1930s when oyster culturing began there or, at a minimum, ten years prior to its appearance in San Francisco Bay.

  13. Reconstructing Eastern Tropical Pacific productivity across Marine Isotope Stage 3 using foraminifera faunal counts

    Science.gov (United States)

    McCourty, M.; Schmidt, M. W.; Glaubke, R.; Hertzberg, J. E.; Marcantonio, F.; Bianchi, T. S.

    2017-12-01

    The El Niño-Southern Oscillation is one of Earth's largest sources of interannual climate variability that has many global environmental impacts. Furthermore, the mean state of the tropical Pacific has the potential to change in the near future due to anthropogenic warming of the planet. In order to provide an analogue for future climate states, there is a critical need to understand how the tropical Pacific evolved across abrupt warming events in Earth's recent past. While most studies have focused on the evolution of ENSO across Marine Isotope Stages (MIS) 1 and 2, the dynamics of the tropical Pacific across the abrupt climate events of MIS 3 are still highly contentious. To develop a record of past changes in upwelling intensity in the EEP, a parameter critically linked to the tropical Pacific mean state, we quantify the faunal abundances of 6 planktonic foraminifera species from piston core MV1014-02-17JC (00° 10.83'S, 85° 52.00'W; 2846 m depth) on the Carnegie Ridge from 35 - 59 kyr. The relative abundance of Globigerina bulloides, a species associated with upwelling conditions, and 5 other planktonic foraminifera suggest an increase in water column productivity during Heinrich Event 4 and across several Dansgaard-Oeschger stadial intervals. Initial results suggest that stadials in the North Atlantic are associated with more permanent La Niña-like conditions in the EEP. However, multiple lines of evidence suggest that depth intervals in our core between 43.7 - 55.7 kyr were impacted by intense dissolution due to changes in bottom water chemistry, impacting the fidelity of our faunal count records across this interval. Future work includes extending our faunal record back to 100 kyr to include Heinrich Events 6 - 8.

  14. Deglacial Western Equatorial Pacific pCO2 Reconstruction Using Boron Isotopes of Planktonic Foraminiferas

    Science.gov (United States)

    Kubota, K.; Yokoyama, Y.; Ishikawa, T.; Sagawa, T.; Ikehara, M.; Yamazaki, T.

    2017-12-01

    During the last deglaciation (ca. 19 - 11 ka), partial pressure of CO2 (pCO2) of the atmosphere increased by 80 μatm. Many paleoceanographers point out that the ocean had played an important role in atmospheric CO2 rise, since the ocean have 60 times larger capacity to store carbon compared to the atmosphere. However, evidence on where carbon was transferred from the ocean to the atmosphere is still lacking, hampering our understanding of global carbon cycles in glacial-interglacial timescales. Boron isotope of skeletons of marine calcifying organisms such as corals and foraminiferas can pin down where CO2 source/sink existed, because boron isotopes of marine calcium carbonates is dependent on seawater pH, from which pCO2 of the past seawater can be reconstructed. In previous studies using the boron isotope teqnique, Martinez-Boti et al. (2015, Nature) and Kubota et al. (2014, Scientific Reports) revealed that central and eastern parts of the equatorial Pacific acted as a CO2 source (i.e., CO2 emission) during the last deglaciation, suggesting the equatorial Pacific's contribution to atmospheric CO2 rise. However, some conflicting results have been confirmed in a marine sediment record from the western part of the equatorial Pacific (Palmer & Pearson, 2003, Science), making the conclusion elusive. In this presentation, we will show new results of Mg/Ca, oxygen isotope, and boron isotope measurements during the last 35 ka on two species of surface dwelling foraminiferas (Globigerinoides ruber and G. sacculifer) which was hand-picked separatedly from a well-dated marine sediment core recovered from the West Caroline Basin (KR05-15 PC01) (Yamazaki et al., 2008, GRL). From the new records, we will discuss how the equatorial Pacific behaved during the last deglaciation and how it related to the global carbon cycles.

  15. Symbiosis and microbiome flexibility in calcifying benthic foraminifera of the Great Barrier Reef.

    Science.gov (United States)

    Prazeres, Martina; Ainsworth, Tracy; Roberts, T Edward; Pandolfi, John M; Leggat, William

    2017-03-23

    Symbiosis is a phenomenon that allows organisms to colonise a wide range of environments and occupy a variety of ecological niches in marine environments. Large benthic foraminifera (LBF) are crucial marine calcifiers that rely on photo-endosymbionts for growth and calcification, yet the influence of environmental conditions in shaping their interactions with prokaryotic and eukaryotic associates is poorly known. Here, we used next-generation sequencing to identify eukaryotic photosynthesizing and prokaryotic microbes associated with the common LBF Amphistegina lobifera across a physio-chemical gradient on the Great Barrier Reef (GBR). We collected samples from three reef sites located in the inner-, mid- and outer-shelf regions of the northern section of the GBR. Results showed the consistent presence of Bacillaryophyta as the main eukaryotic taxa associated with A. lobifera across all reef sites analysed; however, the abundance and the diversity of prokaryotic organisms varied among reef sites. Inner-shelf specimens showed the highest diversity of prokaryote associates, with a total of 231 genotypes in their core microbiome. A total of 30 taxa were identified in the core microbiome across all reef sites. Within these taxa, Proteobacteria was the most abundant bacteria present. The presence of groups such as Actinobacteria was significantly correlated with inner-shelf populations, whereas the abundance of Bacteroidetes and Firmicutes was associated with A. lobifera collected from mid- and outer-shelf reef sites. We found that benthic foraminifera form stable and persistent symbiosis with eukaryotic partners, but flexible and site-specific associations with prokaryotic microbes that likely influence the ecological success of these crucial calcifying organisms on the GBR.

  16. 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

  17. Functional Convergence in Reduced Genomes of Bacterial Symbionts Spanning 200 My of Evolution

    OpenAIRE

    McCutcheon, John P.; Moran, Nancy A.

    2010-01-01

    The main genomic changes in the evolution of host-restricted microbial symbionts are ongoing inactivation and loss of genes combined with rapid sequence evolution and extreme structural stability; these changes reflect high levels of genetic drift due to small population sizes and strict clonality. This genomic erosion includes irreversible loss of genes in many functional categories and can include genes that underlie the nutritional contributions to hosts that are the basis of the symbiotic...

  18. Aphid symbionts and endogenous resistance traits mediate competition between rival parasitoids.

    Science.gov (United States)

    Kraft, Laura J; Kopco, James; Harmon, Jason P; Oliver, Kerry M

    2017-01-01

    Insects use endogenous mechanisms and infection with protective symbionts to thwart attacks from natural enemies. Defenses that target specific enemies, however, potentially mediate competition between rivals and thereby impact community composition. Following its introduction to North America to control pea aphids (Acyrthosiphon pisum), the parasitoid Aphidius ervi competitively displaced other parasitoids, except for the native Praon pequodorum. The pea aphid exhibits tremendous clonal variation in resistance to A. ervi, primarily through infection with the heritable bacterial symbiont Hamiltonella defensa, although some symbiont-free aphid genotypes encode endogenous resistance. Interestingly, H. defensa strains and aphid genotypes that protect against A. ervi, provide no protection against the closely related, P. pequodorum. Given the specificity of aphid defenses, we hypothesized that aphid resistance traits may contribute to the continued persistence of P. pequodorum. We conducted multiparasitism assays to determine whether aphid resistance traits mediate internal competition between these two solitary parasitoid species, but found this was not the case; P. pequodorum was the successful internal competitor across lines varying in susceptibility to A. ervi. Next, to determine whether resistance traits influence competitive interactions resulting in the stable persistence of P. pequodorum, we established replicated cages varying in the proportion of resistant aphids and recorded successful parasitism for each wasp species over time. As expected, A. ervi outcompeted P. pequodorum in cages containing only susceptible aphids. However, P. pequodorum not only persisted, but was the superior competitor in populations containing any proportion (20-100%) of resistant aphids (20-100%). Smaller scale, better replicated competition cage studies corroborated this finding, and no-competition and behavioral assays provide insight into the processes mediating competition

  19. Genetic connectivity between north and south Mid-Atlantic Ridge chemosynthetic bivalves and their symbionts.

    Directory of Open Access Journals (Sweden)

    Karina van der Heijden

    Full Text Available Transform faults are geological structures that interrupt the continuity of mid-ocean ridges and can act as dispersal barriers for hydrothermal vent organisms. In the equatorial Atlantic Ocean, it has been hypothesized that long transform faults impede gene flow between the northern and the southern Mid-Atlantic Ridge (MAR and disconnect a northern from a southern biogeographic province. To test if there is a barrier effect in the equatorial Atlantic, we examined phylogenetic relationships of chemosynthetic bivalves and their bacterial symbionts from the recently discovered southern MAR hydrothermal vents at 5°S and 9°S. We examined Bathymodiolus spp. mussels and Abyssogena southwardae clams using the mitochondrial cytochrome c oxidase subunit I (COI gene as a phylogenetic marker for the hosts and the bacterial 16S rRNA gene as a marker for the symbionts. Bathymodiolus spp. from the two southern sites were genetically divergent from the northern MAR species B. azoricus and B. puteoserpentis but all four host lineages form a monophyletic group indicating that they radiated after divergence from their northern Atlantic sister group, the B. boomerang species complex. This suggests dispersal of Bathymodiolus species from north to south across the equatorial belt. 16S rRNA genealogies of chemoautotrophic and methanotrophic symbionts of Bathymodiolus spp. were inconsistent and did not match the host COI genealogy indicating disconnected biogeography patterns. The vesicomyid clam Abyssogena southwardae from 5°S shared an identical COI haplotype with A. southwardae from the Logatchev vent field on the northern MAR and their symbionts shared identical 16S phylotypes, suggesting gene flow across the Equator. Our results indicate genetic connectivity between the northern and southern MAR and suggest that a strict dispersal barrier does not exist.

  20. Comparative sequence analysis of bacterial symbionts from the marine sponges Geodia cydonium and Ircinia muscarum

    OpenAIRE

    Zuppa, Antonio; Costantini, Susan; Costantini, Maria

    2014-01-01

    Marine sponges (Porifera) live in a symbiotic relationship with microorganisms, primarily bacteria. Recently, several studies indicated that sponges are the most prolific source of biologically-active compounds produced by symbiotic microorganisms rather than by the sponges themselves. In the present study we characterized the bacterial symbionts from two Demospongiae, Ircinia muscarum and Geodia cydonium. We amplified 16S rRNA by PCR, using specific bacterial-primers. The phylogenetic analys...

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

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    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

  2. Nocturnal Production of Endospores in Natural Populations of Epulopiscium-Like Surgeonfish Symbionts

    OpenAIRE

    Flint, Joseph F.; Drzymalski, Dan; Montgomery, W. Linn; Southam, Gordon; Angert, Esther R.

    2005-01-01

    Prior studies have described a morphologically diverse group of intestinal microorganisms associated with surgeonfish. Despite their diversity of form, 16S rRNA gene surveys and fluorescent in situ hybridizations indicate that these bacteria are low-G+C gram-positive bacteria related to Epulopiscium spp. Many of these bacteria exhibit an unusual mode of reproduction, developing multiple offspring intracellularly. Previous reports have suggested that some Epulopiscium-like symbionts produce do...

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

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    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.

  4. Facultative symbiont Hamiltonella confers benefits to Bemisia tabaci (Hemiptera: Aleyrodidae), an invasive agricultural pest worldwide.

    Science.gov (United States)

    Su, Qi; Oliver, Kerry M; Pan, Huipeng; Jiao, Xiaoguo; Liu, Baiming; Xie, Wen; Wang, Shaoli; Wu, Qingjun; Xu, Baoyun; White, Jennifer A; Zhou, Xuguo; Zhang, Youjun

    2013-12-01

    Bacterial symbionts infect most insect species, including important pests such as whitefly, Bemisia tabaci (Gennadius) (Hemiptera: Aleyrodidae), and often exert important effects on host ecology. The facultative symbiont Hamiltonella is found at high frequencies in the B. tabaci MED (type: Mediterranean-MED) in China. The prevalence of this symbiont in natural populations suggests beneficial effects of infection or manipulation of host reproduction. To date, however, no empirical studies on the biological role of Hamiltonella on the host B. tabaci have been reported. Here, we investigated the effects of Hamiltonella infection on the sex ratio and several fitness parameters in B. tabaci MED by comparing Hamiltonella-infected whiteflies with Hamiltonella-free ones. We found that Hamiltonella-infected whiteflies produced significantly more eggs, exhibited significantly higher nymphal survival, faster development times, and larger adult body size in comparison with Hamiltonella-free whiteflies, while no evidence of reproductive manipulation by Hamiltonella were found in B. tabaci MED. In conclusion, Hamiltonella infection substantially enhanced B. tabaci MED performance. This beneficial role may, at least partially, explain the high prevalence of Hamiltonella in B. tabaci MED populations and may also contribute to their effectiveness in spread of the plant pathogens tomato yellow leaf curl virus.

  5. 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.

  6. Phosphatidylinositol 3-kinase function at very early symbiont perception: a local nodulation control under stress conditions?

    Science.gov (United States)

    Robert, Germán; Muñoz, Nacira; Alvarado-Affantranger, Xochitl; Saavedra, Laura; Davidenco, Vanina; Rodríguez-Kessler, Margarita; Estrada-Navarrete, Georgina; Sánchez, Federico; Lascano, Ramiro

    2018-04-09

    Root hair curling is an early and essential morphological change required for the success of the symbiotic interaction between legumes and rhizobia. At this stage rhizobia grow as an infection thread within root hairs and are internalized into the plant cells by endocytosis, where the PI3K enzyme plays important roles. Previous observations show that stress conditions affect early stages of the symbiotic interaction, from 2 to 30 min post-inoculation, which we term as very early host responses, and affect symbiosis establishment. Herein, we demonstrated the relevance of the very early host responses for the symbiotic interaction. PI3K and the NADPH oxidase complex are found to have key roles in the microsymbiont recognition response, modulating the apoplastic and intracellular/endosomal ROS induction in root hairs. Interestingly, compared with soybean mutant plants that do not perceive the symbiont, we demonstrated that the very early symbiont perception under sublethal saline stress conditions induced root hair death. Together, these results highlight not only the importance of the very early host-responses on later stages of the symbiont interaction, but also suggest that they act as a mechanism for local control of nodulation capacity, prior to the abortion of the infection thread, preventing the allocation of resources/energy for nodule formation under unfavorable environmental conditions.

  7. Rare symbionts may contribute to the resilience of coral-algal assemblages.

    Science.gov (United States)

    Ziegler, Maren; Eguíluz, Víctor M; Duarte, Carlos M; Voolstra, Christian R

    2018-01-01

    The association between corals and photosynthetic dinoflagellates (Symbiodinium spp.) is the key to the success of reef ecosystems in highly oligotrophic environments, but it is also their Achilles' heel due to its vulnerability to local stressors and the effects of climate change. Research during the last two decades has shaped a view that coral host-Symbiodinium pairings are diverse, but largely exclusive. Deep sequencing has now revealed the existence of a rare diversity of cryptic Symbiodinium assemblages within the coral holobiont, in addition to one or a few abundant algal members. While the contribution of the most abundant resident Symbiodinium species to coral physiology is widely recognized, the significance of the rare and low abundant background Symbiodinium remains a matter of debate. In this study, we assessed how coral-Symbiodinium communities assemble and how rare and abundant components together constitute the Symbiodinium community by analyzing 892 coral samples comprising >110 000 unique Symbiodinium ITS2 marker gene sequences. Using network modeling, we show that host-Symbiodinium communities assemble in non-random 'clusters' of abundant and rare symbionts. Symbiodinium community structure follows the same principles as bacterial communities, for which the functional significance of rare members (the 'rare bacterial biosphere') has long been recognized. Importantly, the inclusion of rare Symbiodinium taxa in robustness analyses revealed a significant contribution to the stability of the host-symbiont community overall. As such, it highlights the potential functions rare symbionts may provide to environmental resilience of the coral holobiont.

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

    Science.gov (United States)

    Singh, Lamabam Peter

    2011-01-01

    Fungal symbionts have been found to be associated with every plant studied in the natural ecosystem, where they colonize and reside entirely or partially in the internal tissues of their host plant. 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 and 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 an 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. PMID:21512319

  9. Nocturnal production of endospores in natural populations of epulopiscium-like surgeonfish symbionts.

    Science.gov (United States)

    Flint, Joseph F; Drzymalski, Dan; Montgomery, W Linn; Southam, Gordon; Angert, Esther R

    2005-11-01

    Prior studies have described a morphologically diverse group of intestinal microorganisms associated with surgeonfish. Despite their diversity of form, 16S rRNA gene surveys and fluorescent in situ hybridizations indicate that these bacteria are low-G+C gram-positive bacteria related to Epulopiscium spp. Many of these bacteria exhibit an unusual mode of reproduction, developing multiple offspring intracellularly. Previous reports have suggested that some Epulopiscium-like symbionts produce dormant or phase-bright intracellular offspring. Close relatives of Epulopiscium, such as Metabacterium polyspora and Clostridium lentocellum, are endospore-forming bacteria, which raises the possibility that the phase-bright offspring are endospores. Structural evidence and the presence of dipicolinic acid demonstrate that phase-bright offspring of Epulopiscium-like bacteria are true endospores. In addition, endospores are formed as part of the normal daily life cycle of these bacteria. In the populations studied, mature endospores were seen only at night and the majority of cells in a given population produced one or two endospores per mother cell. Phylogenetic analyses confirmed the close relationship between the endospore-forming surgeonfish symbionts characterized here and previously described Epulopiscium spp. The broad distribution of endospore formation among the Epulopiscium phylogenetic group raises the possibility that sporulation is a characteristic of the group. We speculate that spore formation in Epulopiscium-like symbionts may be important for dispersal and may also enhance survival in the changing conditions of the fish intestinal tract.

  10. Verminephrobacter eiseniae gen. nov., sp. nov., a nephridial symbiont of the earthworm Eisenia foetida (Savigny).

    Science.gov (United States)

    Pinel, Nicolás; Davidson, Seana K; Stahl, David A

    2008-09-01

    A Gram-negative, flagellated, heterotrophic, catalase-negative, rod-shaped bacterium previously identified as an earthworm symbiont was isolated from nephridia of the earthworm Eisenia foetida. Comparisons of 16S rRNA gene sequences indicated its relatedness to the betaproteobacterial genus Acidovorax and the novel isolates shared 92-94% sequence similarity with recognized species of this genus. Gene sequence phylogenies revealed that the group of earthworm symbionts formed a cohesive and independent clade. The DNA G+C content was 67.0+/-0.2 mol%. Major fatty acids were C(16:0), C(16:1)omega7c and C(17:0) cyclo. While capable of growing in fully aerated media, all isolates favoured low oxygen concentrations and all required biotin or a mix of amino acids in order to grow on defined mineral media. Based on phylogenies inferred from three housekeeping gene sequences (gap, recA and rpoC), DNA-DNA hybridization values, the unique ecology and the distinct physiology of the novel strains, the new genus Verminephrobacter gen. nov. is proposed for the earthworm nephridial symbionts. The name Verminephrobacter eiseniae sp. nov. is proposed for the type species with strain EF01-2(T) (=ATCC BAA-1489(T)=DSM 19286(T)) as the type strain of the type species.

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

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    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. 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.

  13. Rare symbionts may contribute to the resilience of coral–algal assemblages

    KAUST Repository

    Ziegler, Maren

    2017-12-01

    The association between corals and photosynthetic dinoflagellates (Symbiodinium spp.) is the key to the success of reef ecosystems in highly oligotrophic environments, but it is also their Achilles‘ heel due to its vulnerability to local stressors and the effects of climate change. Research during the last two decades has shaped a view that coral host–Symbiodinium pairings are diverse, but largely exclusive. Deep sequencing has now revealed the existence of a rare diversity of cryptic Symbiodinium assemblages within the coral holobiont, in addition to one or a few abundant algal members. While the contribution of the most abundant resident Symbiodinium species to coral physiology is widely recognized, the significance of the rare and low abundant background Symbiodinium remains a matter of debate. In this study, we assessed how coral–Symbiodinium communities assemble and how rare and abundant components together constitute the Symbiodinium community by analyzing 892 coral samples comprising >110 000 unique Symbiodinium ITS2 marker gene sequences. Using network modeling, we show that host–Symbiodinium communities assemble in non-random ‘clusters‘ of abundant and rare symbionts. Symbiodinium community structure follows the same principles as bacterial communities, for which the functional significance of rare members (the ‘rare bacterial biosphere’) has long been recognized. Importantly, the inclusion of rare Symbiodinium taxa in robustness analyses revealed a significant contribution to the stability of the host–symbiont community overall. As such, it highlights the potential functions rare symbionts may provide to environmental resilience of the coral holobiont.

  14. Variability of the planktonic foraminifera community across the Eocene/Oligocene boundary, Fuente Caldera Section, Baetic Ranges (Spain)

    Science.gov (United States)

    Legarda-Lisarri, A.

    2013-12-01

    During the Eocene/Oligocene transition, in a massive extinction event that took place about 33.7 million years ago, the current high resolution study analyzes qualitatively and quantitatively the community structure of the planktonic foraminifera that were preserved in the hemipelagic sediments of the Tethys Sea. The sampled section of the Fuente Caldera column, located in the Baetic mountain ranges, spans a register of 396,551.7 years. Based in the identification of 27 species, that belong to 13 genera and 2 families of foraminifera, there have been found three biozones of Gonzalvo Zonation (Gonzalvo, 2002) in the studied stratigraphic interval: Turborotalia cocoaensis and Cribrohantkenina lazzarii Biozones (Rupelian), and Paragloborotalia increbescens (Priabonian). The planktonic foraminifera associations variability patterns are defined by paleoecologic indexes (diversity index, high and low latitude species index and planktonic and benthic foraminifera index), by geochemical proxies: δ18O and δ13C and by 'Q' Mode Factor Analysis. They prove that the deposition environment is outer platform and also, they suggest that the studied area in the Tethys Sea underwent many thermal pulses, during which some species extinct or appear. In the first extinction event the species Turborotalia cocoaensis and Turborotalia cunialensis became extinct. In the second one, Hantkenina alabamensis, Hantkenina brevispina, Cribrohantkenina lazzarii and Pseudohastigerina micra became extinct while a succession occured; Globigerina officinalis, Globoturborotalita anguliofficinalis and Tenuitellinata angustiumbilicata appeared. The cooling event that finished in the Lower Oligocene was the biggest of these pulses, which was extremely abrupt and corresponds to the Oi-1 event that was described by Miller (Miller, 1991). All this evidences that the planktonic foraminifera extinction in the Upper Eocene was a gradual and fast event, what is supported by the Factor Analysis application. Key

  15. Hybrid superconductor magnet bearings

    Science.gov (United States)

    Chu, Wei-Kan

    1995-01-01

    Hybrid superconductor magnet bearings (HSMB's) utilize high temperature superconductors (HTS's) together with permanent magnets to form a frictionless interface between relatively rotating parts. They are low mass, stable, and do not incur expenditure of energy during normal operation. There is no direct physical contact between rotor and stator, and hence there is no wear and tear. However, just as any other applications of HTS's, it requires a very cold temperature to function. Whereas this might be perceived as a disadvantage on earth, it is of no great concern in space or on the moon. To astronomers, the moon is an excellent site for an observatory, but the cold and dusty vacuum environment on the moon precludes the use of mechanical bearings on the telescope mounts. Furthermore, drive mechanisms with very fine steps, and hence bearings with extremely low friction are needed to track a star from the moon, because the moon rotates very slowly. All aspects considered, the HSMB is about the only candidate that fits in naturally. Here, we present a design for one such bearing, capable of supporting a telescope that weighs about 3 lbs on Earth.

  16. Constraining Seasonal and Vertical Distributions of Planktonic Foraminifera for Paleoclimate Reconstruction Since MIS3 at the Axial Seamount, Juan de Fuca Ridge

    Science.gov (United States)

    Chen, S. L.; Ravelo, A. C.; Clague, D. A.

    2015-12-01

    The California Current is an upwelling region with dynamic interactions between circulation, biological productivity and ecology. A 77 cm piston push core was taken from the Juan de Fuca Ridge Axial Seamount using a Remotely Operated Vehicle (ROV) (2213m, 45.55º N, 130.08º W), an active submarine volcano ~480 km off Oregon's coast. Five radiocarbon dates indicate that the sediment ranges from 42.6 ka at 77 cm to 17.6 ka at 15 cm, with an average sediment accumulation rate of 2.47 cm/ka from 77-15 cm, and an average rate of 0.85 cm/ka during the postglacial period (the core representing subtropical, subartic, and arctic fauna have been used to constrain changes in vertical and seasonal temperature since Marine Isotope Stage 3 (MIS3). Measurements of δ18O of the upwelling species Globigerina bulloides, the thermocline dwelling species Neogloboquadrina dutertrei, and the warm mixed-layer species Orbulina universa are offset from each other, reflecting vertical and seasonal variation among the planktonic foraminifera. Of the three species, G. bulloides shows the least variation in δ18O, possibly indicating that marked changes in temperature are masking changes in the δ18O of seawater due to global ice volume changes. G. bulloides and O. universa δ18O values are similar in MIS 3 and diverge with time, indicating the development of strong seasonal succession of species, since the last glacial maximum. Bulk nitrogen isotopes and nitrogen flux provide additional constraints on upwelling strength and insight into local biological productivity and nutrient dynamics. Obtaining Mg/Ca data will clarify the δ 18O interpretation except deep in the core where metal-bearing authigenic precipitates affect Mg concentrations. These climatic proxies together provide insight into how global climate change and local seamount volcanism impacts regional productivity in the California Current.

  17. Are aphid parasitoids locally adapted to the prevalence of defensive symbionts in their hosts?

    Science.gov (United States)

    Vorburger, Christoph; Rouchet, Romain

    2016-12-12

    Insect parasitoids are under strong selection to overcome their hosts' defences. In aphids, resistance to parasitoids is largely determined by the presence or absence of protective endosymbionts such as Hamiltonella defensa. Hence, parasitoids may become locally adapted to the prevalence of this endosymbiont in their host populations. To address this, we collected isofemale lines of the aphid parasitoid Lysiphlebus fabarum from 17 sites in Switzerland and France, at which we also estimated the frequency of infection with H. defensa as well as other bacterial endosymbionts in five important aphid host species. The parasitoids' ability to overcome H. defensa-mediated resistance was then quantified by estimating their parasitism success on a single aphid clone (Aphis fabae fabae) that was either uninfected or experimentally infected with one of three different isolates of H. defensa. The five aphid species (Aphis fabae fabae, A. f. cirsiiacanthoides, A. hederae, A. ruborum, A. urticata) differed strongly in the relative frequencies of infection with different bacterial endosymbionts, but there was also geographic variation in symbiont prevalence. Specifically, the frequency of infection with H. defensa ranged from 22 to 47 % when averaged across species. Parasitoids from sites with a high prevalence of H. defensa tended to be more infective on aphids possessing H. defensa, but this relationship was not significant, thus providing no conclusive evidence that L. fabarum is locally adapted to the occurrence of H. defensa. On the other hand, we observed a strong interaction between parasitoid line and H. defensa isolate on parasitism success, indicative of a high specificity of symbiont-conferred resistance. This study is the first, to our knowledge, to test for local adaptation of parasitoids to the frequency of defensive symbionts in their hosts. While it yielded useful information on the occurrence of facultative endosymbionts in several important host species of L

  18. 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

  19. 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

  20. Subcuticular bacteria from the brittle star Ophiactis balli (Echinodermata: Ophiuroidea) represent a new lineage of extracellular marine symbionts in the alpha subdivision of the class Proteobacteria.

    Science.gov (United States)

    Burnett, W J; McKenzie, J D

    1997-01-01

    Many species of echinoderms, in all five extant classes, contain subcuticular bacterial symbionts (SCB). The role of these extracellular symbionts and the nature of the relationship remain unclear. We have sequenced 16S rRNA genes from symbionts to determine their phylogenetic affinities. Symbionts of an ophiuroid, Ophiactis balli, appear closely related to bacteria within the alpha group of the class Proteobacteria, including intracellular endosymbionts and pathogens. SCB are clearly of separate origin from other documented major groups of marine symbiotic bacteria. PMID:9143108

  1. 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

  2. The importance of methane and thiosulfate in the metabolism of the bacterial symbionts of two deep-sea mussels

    Science.gov (United States)

    Fisher, C.R.; Childress, J.J.; Oremland, R.S.; Bidigare, R.R.

    1987-01-01

    Undescribed hydrocarbon-seep mussels were collected from the Louisiana Slope, Gulf of Mexico, during March 1986, and the ultrastructure of their gills was examined and compared to Bathymodiolus thermophilus, a mussel collected from the deep-sea hydrothermal vents on the Gala??pagos Rift in March 1985. These closely related mytilids both contain abundant symbiotic bacteria in their gills. However, the bacteria from the two species are distinctly different in both morphology and biochemistry, and are housed differently within the gills of the two mussels. The symbionts from the seep mussel are larger than the symbionts from B. thermophilus and, unlike the latter, contain stacked intracytoplasmic membranes. In the seep mussel three or fewer symbionts appear to be contained in each host-cell vacuole, while in B. thermophilus there are often more than twenty bacteria visible in a single section through a vacuole. The methanotrophic nature of the seep-mussel symbionts was confirmed in 14C-methane uptake experiments by the appearance of label in both CO2 and acid-stable, non-volatile, organic compounds after a 3 h incubation of isolated gill tissue. Furthermore, methane consumption was correlated with methanol dehydrogenase activity in isolated gill tissue. Activity of ribulose-1,5-biphosphate (RuBP) carboxylase and 14CO2 assimilation studies indicate the presence of either a second type of symbiont or contaminating bacteria on the gills of freshly captured seep mussels. A reevaluation of the nutrition of the symbionts in B. thermophilus indicates that while the major symbiont is not a methanotroph, its status as a sulfur-oxidizing chemoautotroph, as has been suggested previously, is far from proven. ?? 1987 Springer-Verlag.

  3. Compliant hydrodynamic fluid journal bearing

    Science.gov (United States)

    Warren, E. L. (Inventor)

    1985-01-01

    An air bearing structure is described that prevents destructive bending moments within the top foil. Welds are eliminated by mounting the top bearing foil in the bearing cartridge sleeve without using a space block. Tabs or pins at the end of the top bearing foil are restrained by slots or stops formed in the cartridge sleeve. These structural members are free to move in a direction normal to the shaft while being restrained from movement in the direction of shaft rotation.

  4. Selandian-Thanetian larger foraminifera from the lower Jafnayn Formation in the Sayq area (eastern Oman Mountains)

    International Nuclear Information System (INIS)

    Serra-Kiel, J.; Vicedo, V.; Razin, P.; Grelaud, C.

    2016-01-01

    The larger foraminifera of the lower part of the Jafnayn Formation outcropping in the Wadi Sayq, in the Paleocene series of the eastern Oman Mountains, have been studied and described in detail. The analysis have allowed us to develop a detailed systematic description of each taxa, constraining their biostratigraphic distribution and defining the associated foraminifera assemblages. The taxonomic study has permitted us to identify each morphotype precisely and describe three new taxa, namely, Ercumentina sayqensis n. gen. n. sp. Lacazinella rogeri n. sp. and Globoreticulinidae new family. The first assemblage is characterized by the presence of Coskinon sp., Dictyoconus cf. turriculus Hottinger and Drobne, Anatoliella ozalpiensis Sirel, Ercumentina sayqensis n. gen. n. sp. SerraKiel and Vicedo, Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Mandanella cf. flabelliformis Rahaghi, Azzarolina daviesi (Henson), Lockhartia retiata Sander, Dictyokathina simplex Smout and Miscellanites globularis (Rahaghi). The second assemblage is constituted by the forms Pseudofallotella persica (Hottinger and Drobne), Dictyoconus cf. turriculus Hottinger and Drobne, Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Azzarolina daviesi (Henson), Keramosphera? cf. iranica Rahaghi, Lockhartia haimei (Davies), Lockhartia retiata Sander, Sakesaria trichilata Sander, Kathina delseota Smout, Elazigina harabekayisensis Sirel, Daviesina khatiyahi Smout, and Miscellanea juliettae Leppig. The first assemblage can be considered to belong to the Shallow Bentic Zone SBZ2 (early Selandian age), and the second assemblage to the SBZ3 (late Selandian-early Thanetian age).This paper shows, for the first time in the Middle East area, a correlation between the Selandian larger foraminifera and planktonic foraminifera biozones. (Author)

  5. The morphogroups of small agglutinated foraminifera from the Devonian carbonate complex of the Prague Synform, (Barrandian area, Czech Republic)

    Czech Academy of Sciences Publication Activity Database

    Holcová, K.; Slavík, Ladislav

    2013-01-01

    Roč. 386, č. 5 (2013), s. 210-214 ISSN 0031-0182 Grant - others:Rada Programu interní podpory projektů mezinárodní spolupráce AV ČR(CZ) M100131201 Institutional support: RVO:67985831 Keywords : Barrandian area * Early Devonian * foraminifera * morphogroups Subject RIV: DB - Geology ; Mineralogy Impact factor: 2.752, year: 2013

  6. GLOMOMIDIELLA N. GEN. (FORAMINIFERA, MILIOLATA, NEODISCIDAE: A NEW GENUS FROM THE LATE GUADALUPIAN-LOPINGIAN OF HYDRA ISLAND (GREECE

    Directory of Open Access Journals (Sweden)

    DANIEL VACHARD

    2008-11-01

    Full Text Available A new genus of Foraminifera (Miliolata, Cornuspiroidea, Neodiscidae is erected from the late Guadalupian (Capitanian = Midian to Lopingian sedimentary succession of the island of Hydra (Greece. It represents an important phylogenetic form, probably at the origin of several genera (or subfamilies of the authors that became relatively widespread during the Lopingian (Late Permian. Glomomidiella n. gen. is characterized by an entirely glomospiral coiling and rudimentary pseudoseptation. 

  7. Selandian-Thanetian larger foraminifera from the lower Jafnayn Formation in the Sayq area (eastern Oman Mountains)

    Energy Technology Data Exchange (ETDEWEB)

    Serra-Kiel, J.; Vicedo, V.; Razin, P.; Grelaud, C.

    2016-07-01

    The larger foraminifera of the lower part of the Jafnayn Formation outcropping in the Wadi Sayq, in the Paleocene series of the eastern Oman Mountains, have been studied and described in detail. The analysis have allowed us to develop a detailed systematic description of each taxa, constraining their biostratigraphic distribution and defining the associated foraminifera assemblages. The taxonomic study has permitted us to identify each morphotype precisely and describe three new taxa, namely, Ercumentina sayqensis n. gen. n. sp. Lacazinella rogeri n. sp. and Globoreticulinidae new family. The first assemblage is characterized by the presence of Coskinon sp., Dictyoconus cf. turriculus Hottinger and Drobne, Anatoliella ozalpiensis Sirel, Ercumentina sayqensis n. gen. n. sp. SerraKiel and Vicedo, Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Mandanella cf. flabelliformis Rahaghi, Azzarolina daviesi (Henson), Lockhartia retiata Sander, Dictyokathina simplex Smout and Miscellanites globularis (Rahaghi). The second assemblage is constituted by the forms Pseudofallotella persica (Hottinger and Drobne), Dictyoconus cf. turriculus Hottinger and Drobne, Lacazinella rogeri n. sp. Serra-Kiel and Vicedo, Azzarolina daviesi (Henson), Keramosphera? cf. iranica Rahaghi, Lockhartia haimei (Davies), Lockhartia retiata Sander, Sakesaria trichilata Sander, Kathina delseota Smout, Elazigina harabekayisensis Sirel, Daviesina khatiyahi Smout, and Miscellanea juliettae Leppig. The first assemblage can be considered to belong to the Shallow Bentic Zone SBZ2 (early Selandian age), and the second assemblage to the SBZ3 (late Selandian-early Thanetian age).This paper shows, for the first time in the Middle East area, a correlation between the Selandian larger foraminifera and planktonic foraminifera biozones. (Author)

  8. Magnetic bearing and motor

    Science.gov (United States)

    Studer, Philip A. (Inventor)

    1983-01-01

    A magnetic bearing assembly (10) has an intermediate rotatable section (33) having an outer cylindrical member (30) coaxially suspended by a torsion wire (72) around an axially polarized cylindrical magnet (32). Axial alignment between the pole faces (40-43) of the intermediate section (33) and end surfaces (50-53) of opposed end bells (20, 22) provides a path of least reluctance across intervening air gaps (60-63) for the magnetic flux emanating from magnet (32). Radial dislocation increases the reluctance and creates a radial restoring force. Substitution of radially polarized magnets 107 fixed to a magnetically permeable cylinder (32') and insertion of pairs of armature coil windings (109-112) between the cylinder pair (33') provides an integral magnetic bearing and torsion motor (100) able to provide arcuately limited rotational drive.

  9. Passive magnetic bearing system

    Science.gov (United States)

    Post, Richard F.

    2014-09-02

    An axial stabilizer for the rotor of a magnetic bearing provides external control of stiffness through switching in external inductances. External control also allows the stabilizer to become a part of a passive/active magnetic bearing system that requires no external source of power and no position sensor. Stabilizers for displacements transverse to the axis of rotation are provided that require only a single cylindrical Halbach array in its operation, and thus are especially suited for use in high rotation speed applications, such as flywheel energy storage systems. The elimination of the need of an inner cylindrical array solves the difficult mechanical problem of supplying support against centrifugal forces for the magnets of that array. Compensation is provided for the temperature variation of the strength of the magnetic fields of the permanent magnets in the levitating magnet arrays.

  10. Government Risk-Bearing

    CERN Document Server

    1993-01-01

    The u.s. government bulks large in the nation's financial markets. The huge volume of government-issued and -sponsored debt affects the pricing and volume ofprivate debt and, consequently, resource allocation between competing alternatives. What is often not fully appreciated is the substantial influence the federal government wields overresource allocation through its provisionofcreditandrisk-bearing services to the private economy. Because peopleand firms generally seekto avoid risk, atsomeprice they are willing to pay another party to assume the risk they would otherwise face. Insurance companies are a class of private-sector firms one commonly thinks of as providing these services. As the federal government has expanded its presence in the U.S. economy during this century, it has increasingly developed programs aimed at bearing risks that the private sector either would not take on at any price, or would take on but atapricethoughtto besogreatthatmostpotentialbeneficiarieswouldnotpurchase the coverage. To...

  11. COMPOSITION OF BLACK BEAR MILK.

    Science.gov (United States)

    An analysis of black bear ( Ursus americanus Pallas) milk showed that the total solids, fat and protein were much higher and the lactose lower than...either cow or human milk. In comparison with polar bear (Thalarcotos maritimus ), the black bear milk was lower in fat, protein and total calories. (Author)

  12. Frictionless Bearing Uses Permanent Magnets

    Science.gov (United States)

    1965-01-01

    The purpose of this innovation was to develop a frictionless bearing for high speed, light load applications. The device involves the incorporation of permanent magnets in the bearing design. The repulsion of like magnetic poles provides concentric support of the inner member so that no metallic contact occurs between the bearing surfaces.

  13. Rotating plug bearing and seal

    International Nuclear Information System (INIS)

    Wade, E.E.

    1977-01-01

    Disclosed is a bearing and seal structure for nuclear reactors utilizing rotating plugs above the nuclear reactor vessel. The structure permits lubrication of bearings and seals of the rotating plugs without risk of the lubricant draining into the reactor vessel below. The structure permits lubrication by utilizing a rotating outer race bearing. 19 claims, 3 figures

  14. Biocenoses of benthic foraminifera of the Aveiro Continental Shelf (Portugal: influence of the upwelling events and other shelf processes

    Directory of Open Access Journals (Sweden)

    Maria Virgínia Alves Martins

    2017-03-01

    Full Text Available This work aims to compare the dimensions and composition of benthic foraminiferal biocenoses (living specimens during two summer sampling events. Forty-four sediment samples were collected on the Aveiro Continental Shelf (Center of Portugal (latitude of 40º30'N-40º50'N, longitude of 8º46'W-9º20'W for granulometry, total organic matter (TOM and living foraminiferal analyses. The sediment samples were collected during summers of 1994 and 1995, on stations located along transects (east-west direction and between the bathymetries of 10-200 m. During the sampling campaigns, measurements of salinity, temperature and density data were recorded in the water column. The results showed that the living assemblages were mainly found in stations located between 20-80 m depth. The abundance of living foraminifera was generally reduced at depths <20 m in the so-called “coastal deposits”, where the sediments are frequently remobilized and transported by the littoral drift. Living benthic foraminiferal densities were also reduced in stations at 80-200 m depth, despite the high sedimentary TOM contents. Results obtained in this work indicate that, in this marine setting, the most determinant factors for the dimension and composition of living foraminifera are not the sediments’ granulometry and organic matter content. In fact, the coastal dynamics, sediment stability, availability of quality food, among other factors, such as the bottom salinity oscillations and their combination, should better explain the abundance of living foraminifera and the biocenoses composition.

  15. Benthic Foraminifera and Bacterial Activity as a Proxy for Environmental Characterization in Potengi Estuary, Rio Grande do Norte, Brazil

    Directory of Open Access Journals (Sweden)

    Frederico S. da Silva

    2010-01-01

    Full Text Available The aim of this study was to identify possible zonation patterns and assess the environmental impact on the Potengi River Estuary, Rio Grande do Norte State, through the distribution of benthic foraminifera associated to bacterial activity and abiotic parameters. Six sediment samples were collected from locations that presented clear signs of pollution. The environment was predominantly anaerobic and fermentation occurred at all sites. Forty-two species of foraminifera were identified. The dominant species were Ammonia tepida and Arenoparrella mexicana, which are known to be opportunistic, and able to adapt to rapidly changing conditions. CCA analyses showed that salinity and organic matter, followed by bacterial carbon, were more strongly linked to organism distribution in the Potengi River Estuary. Dissolved oxygen concentration, temperature and total organic matter were higher at the estuary mouth than at the other sites, creating favorable conditions for foraminiferal growth and allowing the faunistic succession on the upper estuary. As foraminifera assemblages when associated to environmental parameters can be used as efficient proxies for environmental diagnosis, these results suggest that the Potengi Estuary is under great stress from the surrounding urban development.

  16. Late Neogene foraminifera from the northern Namibian continental shelf and the transition to the Benguela Upwelling System

    Science.gov (United States)

    Bergh, Eugene W.; Compton, John S.; Frenzel, Peter

    2018-05-01

    Middle Miocene to Plio-Pleistocene foraminifera provide insights into the palaeoenvironment on the northern Namibian continental shelf located at the far northern end of the present-day Benguela Upwelling System (BUS). Biostratigraphy and Strontium Isotope Stratigraphy (SIS) of the recovered basal olive-green mud unit indicate an age of 16 to 14 Ma. A sharp, erosional contact separates the basal mud from the overlying Plio-Pleistocene gravelly pelletal phosphorite sands. Grain size data, P/B ratios and benthic diversity indices indicate a change between the middle Miocene and overlying Plio-Pleistocene palaeoenvironments linked to the timing and conditions associated with the initiation of the BUS. The different lithological units and microfossil assemblages in the olive-green mud unit and the overlying pelletal phosphorite units support the late Miocene initiation of the BUS and the northwards migration of the Angola-Benguela Front. Planktic foraminifera indicate a shift from warmer surface water conditions to cooler conditions during the initiation of the BUS. Benthic palaeobathymetric ranges and P/B ratios are consistent with outer shelf water depths suggesting a deeper palaeoenvironment during the Mid-Miocene Climatic Optimum (MMCO) than today. Benthic foraminifera in the middle Miocene are dominated by large (>1 mm) taxa and adapted to oligotrophic environments before the initiation of the BUS. The benthic assemblage composition indicates that bottom water conditions changed to eutrophic conditions during the Plio-Pleistocene under intensified upwelling conditions.

  17. Marine ecology conditions at Weda Bay, North Maluku based on statistical analysis on distribution of recent foraminifera

    Directory of Open Access Journals (Sweden)

    Kurniasih Anis

    2017-01-01

    Full Text Available Analysis of foraminifera in geology,usually being used to find the age of rocks/ sediments and depositional environment. In this study, recent foraminifera was used not only to determinethe sedimentary environment,but also to estimate the ecological condition of the water through a statistical approach.Analysis was performed quantitatively in 10 surface seabed sediment samples in Weda Bay North Maluku. The analysis includes dominance (Sympson Index, diversity and evenness (Shannon Index, and the ratio of planktonic -benthic. The results were shown in the plotting diagram of M-R-T (Miliolid-Rotalid-Textularid to determine the depositional environment. Quantitative analysis was performed using Past software (paleontological version Statistic 1:29.The analysis result showed there was no domination of certain taxon with a moderate degree of evenness and stable communities and considerably a moderate diversity. The results of this analysis indicated that research area had a stable water conditions with the optimum level of carbonate content, oxygen supply, salinity, and temperature. The ratio of planktonic and benthic indicate the relative depth, which was deeper the water increased the percentage of planktonic foraminifera. Based on M-R-T diagram showed the distribution of sediment deposited on exposed carbonate (carbonate platform environment with normal saline.

  18. Influence of local habitat on the physiological responses of large benthic foraminifera to temperature and nutrient stress.

    Science.gov (United States)

    Prazeres, Martina; Uthicke, Sven; Pandolfi, John M

    2016-02-23

    Large benthic foraminifera (LBF) are important for reef sediment formation, but sensitive to elevated temperature and nutrients. However, it is possible that conspecific foraminifera living in different reef sites present divergent response to environmental shifts. We investigated how populations of Amphistegina lobifera from reef sites located along a temperature and nutrient gradient of the northern Great Barrier Reef respond and acclimate to elevated temperature and nitrate under lab-controlled conditions. Generalized linear mixed models showed that interaction between reef sites and temperature or nitrate conditions had a significant effect on survivorship, bleaching frequency and growth rates of A. lobifera. Further physiological analyses of antioxidant capacity and Ca-ATPase activity showed that populations collected from the inner-shelf sites (highest nutrient levels, largest temperature variation) were consistently able to acclimate to both parameters after 30 days. In contrast, foraminifera collected from the reef sites located in the mid- and outer-shelfs were significantly more sensitive to elevated temperatures and nitrate. Our results highlight the importance of local habitat in shaping the tolerance of LBF to changing environmental conditions; populations that live in stable environments are more sensitive to elevated temperature and nitrate, even within their fundamental tolerance range, than those that experience fluctuating conditions.

  19. Radium bearing waste disposal

    International Nuclear Information System (INIS)

    Tope, W.G.; Nixon, D.A.; Smith, M.L.; Stone, T.J.; Vogel, R.A.; Schofield, W.D.

    1995-01-01

    Fernald radium bearing ore residue waste, stored within Silos 1 and 2 (K-65) and Silo 3, will be vitrified for disposal at the Nevada Test Site (NTS). A comprehensive, parametric evaluation of waste form, packaging, and transportation alternatives was completed to identify the most cost-effective approach. The impacts of waste loading, waste form, regulatory requirements, NTS waste acceptance criteria, as-low-as-reasonably-achievable principles, and material handling costs were factored into the recommended approach

  20. The long way of planktonic Foraminifera from biostratigraphy to paleoceanography (Jean Baptiste Lamarck Medal Lecture)

    Science.gov (United States)

    Premoli Silva, Isabella

    2014-05-01

    The mid of the last century was a time of flourishing studies concerning the importance of planktonic foraminifera in precisely dating and correlating sedimentary successions after the publication of the first biostratigraphic schemes provided by the Suisse Group (i.e. Kugler, Bolli, Broennimann) from the Caribbean region and former Southern USSR (Subbotina). Soon after Bolli's Trinidad scheme was widespread, planktonic foraminiferal distribution from Upper Cretaceous to Miocene was investigated intensively for dating the Neogene stratotypes, whose identifications were mainly based on poorly age-diagnostic, facies-controlled macrofossils, and for calibrating Paleogene larger foraminiferal distributions. Since these early works planktonic foraminiferal biostratigraphy was continously ameliorated, extended in time from Early Cretaceous to Recent by several authors and from different settings and domains, reaching progressively the current higher resolution, now calibrated to calcareous nannofossil distributions. To be mentioned, the detailed biostratigraphic studies on the Gubbio section (central Italy) provided (1) the first carefull documentation of the mass extinction of Cretaceous planktonic foraminifera, the presence of tiny Cretaceous survivors, and the rapid recovery of Danian assemblages, and (2) the first calibration of the Upper Cretaceous to Eocene reversal polarity scale in which the K/Pg boundary was demonstrated to fall within the magnetic reversal C29r. A major step forward was the recovery, since 1968, of several thousand of cores from over 1000 holes drilled in all oceans by the DSDP, ODP and IODP projects. The recovery of deep-sea sediments from all latitudes opened a new research field, the paleoceanography. Based on the large knowledge acquired on modern organisms in the '60s, for the Paleogene and Cretaceous reconstructions we started from the assumption that these extinct organisms lived in the water column like their modern counterpart and were

  1. Effects of long-term starvation on a host bivalve (Codakia orbicularis, Lucinidae) and its symbiont population.

    Science.gov (United States)

    Caro, Audrey; Got, Patrice; Bouvy, Marc; Troussellier, Marc; Gros, Olivier

    2009-05-01

    The bivalve Codakia orbicularis, hosting sulfur-oxidizing gill endosymbionts, was starved (in artificial seawater filtered through a 0.22-mum-pore-size membrane) for a long-term experiment (4 months). The effects of starvation were observed using transmission electron microscopy, fluorescence in situ hybridization and catalyzed reporter deposition (CARD-FISH), and flow cytometry to monitor the anatomical and physiological modifications in the gill organization of the host and in the symbiotic population housed in bacteriocytes. The abundance of the symbiotic population decreased through starvation, with a loss of one-third of the bacterial population each month, as shown by CARD-FISH. At the same time, flow cytometry revealed significant changes in the physiology of symbiotic cells, with a decrease in cell size and modifications to the nucleic acid content, while most of the symbionts maintained a high respiratory activity (measured using the 5-cyano-2,3-ditolyl tetrazolium chloride method). Progressively, the number of symbiont subpopulations was reduced, and the subsequent multigenomic state, characteristic of this symbiont in freshly collected clams, turned into one and five equivalent genome copies for the two remaining subpopulations after 3 months. Concomitant structural modifications appeared in the gill organization. Lysosymes became visible in the bacteriocytes, while large symbionts disappeared, and bacteriocytes were gradually replaced by granule cells throughout the entire lateral zone. Those data suggested that host survival under these starvation conditions was linked to symbiont digestion as the main nutritional source.

  2. A nonnative and a native fungal plant pathogen similarly stimulate ectomycorrhizal development but are perceived differently by a fungal symbiont.

    Science.gov (United States)

    Zampieri, Elisa; Giordano, Luana; Lione, Guglielmo; Vizzini, Alfredo; Sillo, Fabiano; Balestrini, Raffaella; Gonthier, Paolo

    2017-03-01

    The effects of plant symbionts on host defence responses against pathogens have been extensively documented, but little is known about the impact of pathogens on the symbiosis and if such an impact may differ for nonnative and native pathogens. Here, this issue was addressed in a study of the model system comprising Pinus pinea, its ectomycorrhizal symbiont Tuber borchii, and the nonnative and native pathogens Heterobasidion irregulare and Heterobasidion annosum, respectively. In a 6-month inoculation experiment and using both in planta and gene expression analyses, we tested the hypothesis that H. irregulare has greater effects on the symbiosis than H. annosum. Although the two pathogens induced the same morphological reaction in the plant-symbiont complex, with mycorrhizal density increasing exponentially with pathogen colonization of the host, the number of target genes regulated in T. borchii in plants inoculated with the native pathogen (i.e. 67% of tested genes) was more than twice that in plants inoculated with the nonnative pathogen (i.e. 27% of genes). Although the two fungal pathogens did not differentially affect the amount of ectomycorrhizas, the fungal symbiont perceived their presence differently. The results may suggest that the symbiont has the ability to recognize a self/native and a nonself/nonnative pathogen, probably through host plant-mediated signal transduction. © 2016 The Authors. New Phytologist © 2016 New Phytologist Trust.

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

    Science.gov (United States)

    Rouchet, Romain; Vorburger, Christoph

    2014-06-01

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

  4. Bearing for liquid metal pump

    International Nuclear Information System (INIS)

    Dickinson, R.J.; Pennell, W.E.; Wasko, J.

    1984-01-01

    A liquid metal pump bearing support comprises a series of tangentially oriented spokes that connect the bearing cylinder to the pump internals structure. The spokes may be arranged in a plurality of planes extending from the bearing cylinder to the pump internals with the spokes in one plane being arranged alternately with those in the next plane. The bearing support structure provides the pump with sufficient lateral support for the bearing structure together with the capability of accommodating differential thermal expansion without adversely affecting pump performance

  5. Bearing, gearing, and lubrication technology

    Science.gov (United States)

    Anderson, W. J.

    1978-01-01

    Results of selected NASA research programs on rolling-element and fluid-film bearings, gears, and elastohydrodynamic lubrication are reported. Advances in rolling-element bearing material technology, which have resulted in a significant improvement in fatigue life, and which make possible new applications for rolling bearings, are discussed. Research on whirl-resistant, fluid-film bearings, suitable for very high-speed applications, is discussed. An improved method for predicting gear pitting life is reported. An improved formula for calculating the thickness of elastohydrodynamic films (the existence of which help to define the operating regime of concentrated contact mechanisms such as bearings, gears, and cams) is described.

  6. Benthic foraminifera from the Arabian Sea oxygen minimum zone: towards a paleo-oxygenation proxy.

    Science.gov (United States)

    Clemence, Caulle; Meryem, Mojtahid; Karoliina, Koho; Andy, Gooday; Gert-Jan, Reichart; Gerhard, Schmiedl; Frans, Jorissen

    2014-05-01

    Benthic foraminifera from the Arabian Sea oxygen minimum zone: towards a paleo-oxygenation proxy. C. Caulle1, M. Mojtahid1, K. Koho2,3, A. Gooday4, G. J. Reichart2,3, G. Schmiedl5, F. Jorissen1 1UMR CNRS 6112 LPG-BIAF, University of Angers, 2 bd Lavoisier, 49045 Angers Cedex 2Utrecht University, Faculty of Geosciences, Department of Earth Sciences, Budapestlaan 4, 3584 CD Utrecht, The Netherlands 3Royal Netherland Institute for Sea Research (Royal NIOZ), Landsdiep 4, 1797 SZ 't Horntje (Texel) 4Southampton Oceanography Centre, Empress Dock, European Way, Southampton SO14 3ZH, UK 5Department of Geosciences, University of Hamburg, Bundesstraße 55, 20146 Hamburg, Germany The thermohaline circulation oxygenates the deep ocean sediment and therefore enables aerobic life on the sea-floor. In the past, interruption of this deep water formation occurred several times causing hypoxic to anoxic conditions on the sea-floor leading to major ecological turnover. A better understanding of the interaction between climate and bottom water oxygenation is therefore essential in order to predict future oceanic responses. Presently, permanent (stable over decadal timescale) low-oxygen conditions occur naturally at mid-water depths in the northern Indian Ocean (Arabian Sea). Oxygen Minimum Zones (OMZ) are key areas to understand the hypoxic-anoxic events and their impact on the benthic ecosystem. In this context, a good knowledge of the ecology and life cycle adaptations of the benthic foraminiferal assemblages living in these low oxygen areas is essential. A series of multicores were recovered from three transects showing an oxygen gradient across the OMZ: the Murray Ridge, the Oman margin and the Indian margin. The stations located at the same depths showed slightly different oxygen concentrations and large differences in organic matter content. These differences are mainly related to the geographic location in the Arabian Sea. We investigated at these stations live and dead benthic

  7. Anthropogenic infilling of a Bermudian sinkhole and its impact on sedimentation and benthic foraminifera in the adjacent anchialine cave environment

    Directory of Open Access Journals (Sweden)

    Jacquelyn N. Cresswell

    2017-09-01

    Full Text Available In the mid-20th century, an inland brackish pond from Bermuda, known as Eve’s Pond, was filled with marine sediment from an adjacent coastal lagoon. At this time, an eyewitness reported “…sediment billowing out of the Green Bay Cave for days…”, which is a marine-dominated anchialine cave located proximal to the former location of Eve’s Pond (~200 m. The purpose of this study was to evaluate the potential impact of this infilling event on cave sedimentation and benthic meiofaunal communities, as proxied by the unicellular protists foraminifera that remain preserved in the sediment record. Eight sediment cores were collected from an underwater passage in Green Bay Cave in a transect towards the location where Eve’s Pond was surveyed in 1901 CE. The sediment cores were analyzed for visual and density changes (photography, X-radiography, textural variability, benthic foraminifera fauna and diversity, and radiocarbon dating. The recovered sediment cores mostly sampled a late Holocene carbonate mud facies that had been described during previous research in the cave, with benthic foraminiferal assemblages post-dating the onset of seawater circulating between the saline groundwater flooding the cave and the adjacent Harrington Sound ~1,900 years ago. However, two cores located further into the cave (cores 13 and 17 contain a carbonate sand layer with lagoon foraminifera that is anomalous with respect to the Holocene depositional history of the cave and is most likely related to the mid-20th century infilling of Eve’s Pond. Examination of these two cores showed that after the infilling event, the community of benthic foraminifera rapidly reverted to pre-impact assemblages with foraminiferal stygophiles (e.g., Spirophthalmidium emaciatum, Sigmoilina tenuis, which were not displaced by new colonizers introduced into the cave by the dredge spoils. We caution that the results cannot be extrapolated to the pelagic crustacean community, but the

  8. Bearing construction for refrigeration compresssor

    Science.gov (United States)

    Middleton, Marc G.; Nelson, Richard T.

    1988-01-01

    A hermetic refrigeration compressor has a cylinder block and a crankshaft rotatable about a vertical axis to reciprocate a piston in a cylinder on the cylinder block. A separate bearing housing is secured to the central portion of the cylinder block and extends vertically along the crankshaft, where it carries a pair of roller bearings to journal the crankshaft. The crankshaft has a radially extending flange which is journaled by a thrust-type roller bearing above the bearing housing to absorb the vertical forces on the crankshaft so that all three of the roller bearings are between the crankshaft and the bearing housing to maintain and control the close tolerances required by such bearings.

  9. 77 FR 70423 - Black Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC...

    Science.gov (United States)

    2012-11-26

    ... Bear Hydro Partners, LLC and Black Bear Development Holdings, LLC and Black Bear SO, LLC; Notice of..., 2012, Black Bear Hydro Partners, LLC, sole licensee (transferor) and Black Bear Development Holdings, LLC and Black Bear SO, LLC (transferees) filed an application for the partial the transfer of licenses...

  10. Introgressive hybridization: brown bears as vectors for polar bear alleles.

    Science.gov (United States)

    Hailer, Frank

    2015-03-01

    The dynamics and consequences of introgression can inform about numerous evolutionary processes. Biologists have therefore long been interested in hybridization. One challenge, however, lies in the identification of nonadmixed genotypes that can serve as a baseline for accurate quantification of admixture. In this issue of Molecular Ecology, Cahill et al. (2015) analyse a genomic data set of 28 polar bears, eight brown bears and one American black bear. Polar bear alleles are found to be introgressed into brown bears not only near a previously identified admixture zone on the Alaskan Admiralty, Baranof and Chichagof (ABC) Islands, but also far into the North American mainland. Elegantly contrasting admixture levels at autosomal and X chromosomal markers, Cahill and colleagues infer that male-biased dispersal has spread these introgressed alleles away from the Late Pleistocene contact zone. Compared to a previous study on the ABC Island population in which an Alaskan brown bear served as a putatively admixture-free reference, Cahill et al. (2015) utilize a newly sequenced Swedish brown bear as admixture baseline. This approach reveals that brown bears have been impacted by introgression from polar bears to a larger extent (up to 8.8% of their genome), than previously known, including the bear that had previously served as admixture baseline. No evidence for introgression of brown bear into polar bear is found, which the authors argue could be a consequence of selection. Besides adding new exciting pieces to the puzzle of polar/brown bear evolutionary history, the study by Cahill and colleagues highlights that wildlife genomics is moving from analysing single genomes towards a landscape genomics approach. © 2015 John Wiley & Sons Ltd.

  11. Candidatus Dactylopiibacterium carminicum, a Nitrogen-Fixing Symbiont of Dactylopius Cochineal Insects (Hemiptera: Coccoidea: Dactylopiidae)

    Science.gov (United States)

    Vera-Ponce de León, Arturo; Ormeño-Orrillo, Ernesto; Ramírez-Puebla, Shamayim T.; Rosenblueth, Mónica; Degli Esposti, Mauro; Martínez-Romero, Julio

    2017-01-01

    Abstract The domesticated carmine cochineal Dactylopius coccus (scale insect) has commercial value and has been used for more than 500 years for natural red pigment production. Besides the domesticated cochineal, other wild Dactylopius species such as Dactylopius opuntiae are found in the Americas, all feeding on nutrient poor sap from native cacti. To compensate nutritional deficiencies, many insects harbor symbiotic bacteria which provide essential amino acids or vitamins to their hosts. Here, we characterized a symbiont from the carmine cochineal insects, Candidatus Dactylopiibacterium carminicum (betaproteobacterium, Rhodocyclaceae family) and found it in D. coccus and in D. opuntiae ovaries by fluorescent in situ hybridization, suggesting maternal inheritance. Bacterial genomes recovered from metagenomic data derived from whole insects or tissues both from D. coccus and from D. opuntiae were around 3.6 Mb in size. Phylogenomics showed that dactylopiibacteria constituted a closely related clade neighbor to nitrogen fixing bacteria from soil or from various plants including rice and other grass endophytes. Metabolic capabilities were inferred from genomic analyses, showing a complete operon for nitrogen fixation, biosynthesis of amino acids and vitamins and putative traits of anaerobic or microoxic metabolism as well as genes for plant interaction. Dactylopiibacterium nif gene expression and acetylene reduction activity detecting nitrogen fixation were evidenced in D. coccus hemolymph and ovaries, in congruence with the endosymbiont fluorescent in situ hybridization location. Dactylopiibacterium symbionts may compensate for the nitrogen deficiency in the cochineal diet. In addition, this symbiont may provide essential amino acids, recycle uric acid, and increase the cochineal life span.

  12. Rapid evolution of symbiont-mediated resistance compromises biological control of aphids by parasitoids.

    Science.gov (United States)

    Käch, Heidi; Mathé-Hubert, Hugo; Dennis, Alice B; Vorburger, Christoph

    2018-02-01

    There is growing interest in biological control as a sustainable and environmentally friendly way to control pest insects. Aphids are among the most detrimental agricultural pests worldwide, and parasitoid wasps are frequently employed for their control. The use of asexual parasitoids may improve the effectiveness of biological control because only females kill hosts and because asexual populations have a higher growth rate than sexuals. However, asexuals may have a reduced capacity to track evolutionary change in their host populations. We used a factorial experiment to compare the ability of sexual and asexual populations of the parasitoid Lysiphlebus fabarum to control caged populations of black bean aphids ( Aphis fabae ) of high and low clonal diversity. The aphids came from a natural population, and one-third of the aphid clones harbored Hamiltonella defensa , a heritable bacterial endosymbiont that increases resistance to parasitoids. We followed aphid and parasitoid population dynamics for 3 months but found no evidence that the reproductive mode of parasitoids affected their effectiveness as biocontrol agents, independent of host clonal diversity. Parasitoids failed to control aphids in most cases, because their introduction resulted in strong selection for clones protected by H. defensa . The increasingly resistant aphid populations escaped control by parasitoids, and we even observed parasitoid extinctions in many cages. The rapid evolution of symbiont-conferred resistance in turn imposed selection on parasitoids. In cages where asexual parasitoids persisted until the end of the experiment, they became dominated by a single genotype able to overcome the protection provided by H. defensa . Thus, there was evidence for parasitoid counteradaptation, but it was generally too slow for parasitoids to regain control over aphid populations. It appears that when pest aphids possess defensive symbionts, the presence of parasitoid genotypes able to overcome

  13. Phylogenetic analysis of algal symbionts associated with four North American amphibian egg masses.

    Science.gov (United States)

    Kim, Eunsoo; Lin, Yuan; Kerney, Ryan; Blumenberg, Lili; Bishop, Cory

    2014-01-01

    Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga "Oophila amblystomatis" (Lambert ex Wille), which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the 'Oophila' clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae.

  14. Phylogenetic analysis of algal symbionts associated with four North American amphibian egg masses.

    Directory of Open Access Journals (Sweden)

    Eunsoo Kim

    Full Text Available Egg masses of the yellow-spotted salamander Ambystoma maculatum form an association with the green alga "Oophila amblystomatis" (Lambert ex Wille, which, in addition to growing within individual egg capsules, has recently been reported to invade embryonic tissues and cells. The binomial O. amblystomatis refers to the algae that occur in A. maculatum egg capsules, but it is unknown whether this population of symbionts constitutes one or several different algal taxa. Moreover, it is unknown whether egg masses across the geographic range of A. maculatum, or other amphibians, associate with one or multiple algal taxa. To address these questions, we conducted a phylogeographic study of algae sampled from egg capsules of A. maculatum, its allopatric congener A. gracile, and two frogs: Lithobates sylvatica and L. aurora. All of these North American amphibians form associations with algae in their egg capsules. We sampled algae from egg capsules of these four amphibians from localities across North America, established representative algal cultures, and amplified and sequenced a region of 18S rDNA for phylogenetic analysis. Our combined analysis shows that symbiotic algae found in egg masses of four North American amphibians are closely related to each other, and form a well-supported clade that also contains three strains of free-living chlamydomonads. We designate this group as the 'Oophila' clade, within which the symbiotic algae are further divided into four distinct subclades. Phylogenies of the host amphibians and their algal symbionts are only partially congruent, suggesting that host-switching and co-speciation both play roles in their associations. We also established conditions for isolating and rearing algal symbionts from amphibian egg capsules, which should facilitate further study of these egg mass specialist algae.

  15. 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. © 2013 Society for Applied Microbiology and John Wiley & Sons Ltd.

  16. 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

  17. Endobiotic rugosan symbionts in stromatoporoids from the Sheinwoodian (Silurian of Baltica.

    Directory of Open Access Journals (Sweden)

    Olev Vinn

    Full Text Available A paleoecological study of stromatoporoid endobionts was carried out to discern the relationships between symbiotic rugosans and their stromatoporoid hosts. The earliest endobiotic rugosan symbiont Palaeophyllum sp. in Baltica has only been found in the stromatoporoid Ecclimadictyon astrolaxum from Saaremaa, Estonia. The rugosans are vertically oriented inside the stromatoporoid skeleton. Numerous rugosans have their corallites open at the upper, external surface of stromatoporoids, but many are completely embedded within the stromatoporoids. Stromatoporoid hosts were presumably beneficial for rugosans as elevated substrates on a sea floor that offered a higher tier for feeding. Relative substrate stability in the hydrodynamically active shallow waters may have also been beneficial for the rugosans.

  18. 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...... was not observed. The ammonium transporter has been identified as a voltage-driven channel whereas the symbiosome membrane aspartate transporter appears to be a H+/aspartate symport. The results suggest that nitrogen transfer between the symbionts in pea root nodules involves transfer of amino acids as well...

  19. Antagonistic bacterial interactions help shape host-symbiont dynamics within the fungus-growing ant-microbe mutualism

    DEFF Research Database (Denmark)

    Poulsen, Michael; Erhardt, Daniel P; Molinaro, Daniel J

    2007-01-01

    is likely more complex than in intraspecific cooperative relationship, because of the potential presence of: i) multiple genotypes of microbial species associated with individual hosts, ii) multiple species of symbiotic lineages forming cooperative partner pairings, and iii) additional symbiont lineages......Conflict within mutually beneficial associations is predicted to destabilize relationships, and theoretical and empirical work exploring this has provided significant insight into the dynamics of cooperative interactions. Within mutualistic associations, the expression and regulation of conflict...... relationships between the ant host of the symbionts, as well as the pair-wise genetic distances between strains. The presence of antagonism throughout the phylogenetic diversity of Pseudonocardia symbionts indicates that these reactions likely have shaped the symbiosis from its origin. Antagonism is expected...

  20. A note on the Pavonina flabelliformis D'Orbigny (benthic foraminifera) from the Arabian Sea

    Digital Repository Service at National Institute of Oceanography (India)

    Khare, N.

    . flabelliformis in modern sediments off Karwar suggests and updates the lower depth limit to 33 metre as against reported from deeper regions in previous studies. This will have significant bearing in paleodepth studies of sedimentary strata having fossils...

  1. New species of Cenozoic benthic foraminifera from the former British Petroleum micropalaeontology collection

    Science.gov (United States)

    Fox, Lyndsey R.; Stukins, Stephen; Hill, Tom; Bailey, Haydon

    2018-01-01

    This paper describes four new Cenozoic, deep-water benthic foraminifera from the reference collections at the Natural History Museum in London. The focus is on selected calcareous taxa that are of stratigraphical and/or palaeoecological significance for academic and industrial-related activities. Alabamina heyae (urn:lsid:zoobank.org:act:1E8A66E9-1F4C-4B61-BA97-6E0ECCD0173E), Nonion cepa (urn:lsid:zoobank.org:act:9F36350A-1E49-4D69-B2CC-C83F343E2952), Uvigerina kingi (urn:lsid:zoobank.org:act:C36C89C2-2E65-4FF6-9368-C169B4591995) and Lenticulina stewarti (urn:lsid:zoobank.org:act:485AE871-CECA-44E8-ABD1-BAE2961FFD59) are described with new illustrations. Their biostratigraphic and palaeoecological significance is briefly discussed.

  2. Tolerance of benthic foraminifera to anthropogenic stressors from three sites of the Egyptian coasts

    Directory of Open Access Journals (Sweden)

    Amani Badawi

    2016-03-01

    Full Text Available Surely the coupling of natural and anthropogenic stressors combined with a lack of regulation resulted in the current threat to a large part of coastal marine biodiversity as well as coastal human societies, particularly in highly populated regions. The distribution pattern of benthic foraminifera as sensitive bio-indicator is utilized to assess human-induced impact on the coastal area, at Alexandria, Port Said and Suez cites of Egypt. Twenty-two benthic foraminiferal genera were identified and complied by principal component analysis into four factors through cluster analysis. Cross correlation of the generic composition, distribution and relative abundance of common genera in the three investigated cores revealed three different coastal environments entities. The categorized environment ranged from light human impact as Alexandria site to heavily impacted by human activities as Port Said and Suez sites. Fauna of Alexandria site reflects an increase in un-polluted water activity revealing high-energy erosive environment. The second entity involves Port Said site, which represents a highly stressed coastal environment, corresponding to high-energy transport conditions influenced by fresh water flush from local Manzala Lake via Bougaz El Gamel outlet while Suez site is influenced by marine hypersaline water coupling with intensified levels of industrial and domestic pollution, attributed to the anthropogenic impact.

  3. Larger foraminifera of the Devil's Den and Blue Hole sinkholes, Florida

    Science.gov (United States)

    Cotton, Laura J.; Eder, Wolfgang; Floyd, James

    2018-03-01

    Shallow-water carbonate deposits are well-known from the Eocene of the US Gulf Coast and Caribbean. These deposits frequently contain abundant larger benthic foraminifera (LBF). However, whilst integrated stratigraphic studies have helped to refine the timing of LBF overturning events within the Tethys and Indo-Pacific regions with respect to global bio- and chemo-stratigraphic records, little recent work has been carried out in the Americas. The American LBF assemblages are distinctly different from those of Europe and the Indo-Pacific. It is therefore essential that the American bio-province is included in studies of LBF evolution, biodiversity and climate events to understand these processes on a global scale.Here we present the LBF ranges from two previously unpublished sections spanning 35 and 29 m of the upper Eocene Ocala limestone, as the early stages of a larger project addressing the taxonomy and biostratigraphy of the LBF of Florida. The study indicates that the lower member of the Ocala limestone may be Bartonian rather than Priabonian in age, with implications for the biostratigraphy of the region. In addition, the study highlights the need for multiple sites to assess the LBF assemblages and fully constrain ranges across Florida and the US Gulf and suggests potential LBF events for future integrated stratigraphic study.

  4. Disruptive selection and bet-hedging in planktonic Foraminifera: Shell morphology as predictor of extinctions

    Directory of Open Access Journals (Sweden)

    Manuel F. G. Weinkauf

    2014-10-01

    Full Text Available Extinction is a remarkably difficult phenomenon to study under natural conditions. This is because the outcome of stress exposure and associated fitness reduction is not known until the extinction occurs and it remains unclear whether there is any phenotypic reaction of the exposed population that can be used to predict its fate. Here we take advantage of the fossil record, where the ecological outcome of stress exposure is known. Specifically, we analyze shell morphology of planktonic Foraminifera in sediment samples from the Mediterranean, during an interval preceding local extinctions. In two species representing different plankton habitats, we observe shifts in trait state and decrease in variance in association with non-terminal stress, indicating stabilizing selection. At terminal stress levels, immediately before extinction, we observe increased growth asymmetry and trait variance, indicating disruptive selection and bet-hedging. The pre-extinction populations of both species show a combination of trait states and trait variance distinct from all populations exposed to non-terminal levels of stress. This finding indicates that the phenotypic history of a population may allow the detection of threshold levels of stress, likely to lead to extinction. It is thus an alternative to population dynamics in studying and monitoring natural population ecology.

  5. Technical Note: On methodologies for determining the size-normalised weight of planktic foraminifera

    Directory of Open Access Journals (Sweden)

    C. J. Beer

    2010-07-01

    Full Text Available The size-normalised weight (SNW of planktic foraminifera, a measure of test wall thickness and density, is potentially a valuable palaeo-proxy for marine carbon chemistry. As increasing attention is given to developing this proxy it is important that methods are comparable between studies. Here, we compare SNW data generated using two different methods to account for variability in test size, namely (i the narrow (50 μm range sieve fraction method and (ii the individually measured test size method. Using specimens from the 200–250 μm sieve fraction range collected in multinet samples from the North Atlantic, we find that sieving does not constrain size sufficiently well to isolate changes in weight driven by variations in test wall thickness and density from those driven by size. We estimate that the SNW data produced as part of this study are associated with an uncertainty, or error bar, of about ±11%. Errors associated with the narrow sieve fraction method may be reduced by decreasing the size of the sieve window, by using larger tests and by increasing the number tests employed. In situations where numerous large tests are unavailable, however, substantial errors associated with this sieve method remain unavoidable. In such circumstances the individually measured test size method provides a better means for estimating SNW because, as our results show, this method isolates changes in weight driven by variations in test wall thickness and density from those driven by size.

  6. 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

  7. 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

    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...

  8. Real-time PCR reveals a high incidence of Symbiodinium clade D at low levels in four scleractinian corals across the Great Barrier Reef : implications for symbiont shuffling

    NARCIS (Netherlands)

    Mieog, J. C.; van Oppen, M. J. H.; Cantin, N. E.; Stam, W. T.; Olsen, J. L.

    Reef corals form associations with an array of genetically and physiologically distinct endosymbionts from the genus Symbiodinium. Some corals harbor different clades of symbionts simultaneously, and over time the relative abundances of these clades may change through a process called symbiont

  9. 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.

  10. Arsenophonus and Sodalis Symbionts in Louse Flies: an Analogy to the Wigglesworthia and Sodalis System in Tsetse Flies.

    Science.gov (United States)

    Nováková, Eva; Husník, Filip; Šochová, Eva; Hypša, Václav

    2015-09-01

    Symbiosis between insects and bacteria result in a variety of arrangements, genomic modifications, and metabolic interconnections. Here, we present genomic, phylogenetic, and morphological characteristics of a symbiotic system associated with Melophagus ovinus, a member of the blood-feeding family Hippoboscidae. The system comprises four unrelated bacteria representing different stages in symbiosis evolution, from typical obligate mutualists inhabiting bacteriomes to freely associated commensals and parasites. Interestingly, the whole system provides a remarkable analogy to the association between Glossina and its symbiotic bacteria. In both, the symbiotic systems are composed of an obligate symbiont and two facultative intracellular associates, Sodalis and Wolbachia. In addition, extracellular Bartonella resides in the gut of Melophagus. However, the phylogenetic origins of the two obligate mutualist symbionts differ. In Glossina, the mutualistic Wigglesworthia appears to be a relatively isolated symbiotic lineage, whereas in Melophagus, the obligate symbiont originated within the widely distributed Arsenophonus cluster. Although phylogenetically distant, the two obligate symbionts display several remarkably similar traits (e.g., transmission via the host's "milk glands" or similar pattern of genome reduction). To obtain better insight into the biology and possible role of the M. ovinus obligate symbiont, "Candidatus Arsenophonus melophagi," we performed several comparisons of its gene content based on assignments of the Cluster of Orthologous Genes (COG). Using this criterion, we show that within a set of 44 primary and secondary symbionts, "Ca. Arsenophonus melophagi" is most similar to Wigglesworthia. On the other hand, these two bacteria also display interesting differences, such as absence of flagellar genes in Arsenophonus and their presence in Wigglesworthia. This finding implies that a flagellum is not essential for bacterial transmission via milk glands

  11. 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

    exist in the fungus-growing ants where the symbiotic fungus garden may be an independent source of recognition compounds. To investigate this hypothesis, we quantified the chemical profiles of the fungal symbionts of 18 sympatric colonies of Acromyrmex echinatior and Acromyrmex octospinosus...... 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...

  12. 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...... symbionts, primarily consisting of Entomoplasmatales, Bartonellaceae, Acinetobacter, Wolbachia and Pseudonocardia and that Entomoplasmatales and Bartonellaceae can co-infect specifically associated combinations of hosts and social parasites with identical 16S rRNA genotypes. We reconstructed in more detail...

  13. Computational design of rolling bearings

    CERN Document Server

    Nguyen-Schäfer, Hung

    2016-01-01

    This book comprehensively presents the computational design of rolling bearings dealing with many interdisciplinary difficult working fields. They encompass elastohydrodynamics (EHD), Hertzian contact theory, oil-film thickness in elastohydrodynamic lubrication (EHL), bearing dynamics, tribology of surface textures, fatigue failure mechanisms, fatigue lifetimes of rolling bearings and lubricating greases, Weibull distribution, rotor balancing, and airborne noises (NVH) in the rolling bearings. Furthermore, the readers are provided with hands-on essential formulas based on the up-to-date DIN ISO norms and helpful examples for computational design of rolling bearings. The topics are intended for undergraduate and graduate students in mechanical and material engineering, research scientists, and practicing engineers who want to understand the interactions between these working fields and to know how to design the rolling bearings for automotive industry and many other industries.

  14. Recent expansion of heat-activated retrotransposons in the coral symbiont Symbiodinium microadriaticum

    KAUST Repository

    Chen, Jit Ern

    2017-10-20

    Rising sea surface temperature is the main cause of global coral reef decline. Abnormally high temperatures trigger the breakdown of the symbiotic association between corals and their photosynthetic symbionts in the genus Symbiodinium. Higher genetic variation resulting from shorter generation times has previously been proposed to provide increased adaptability to Symbiodinium compared to the host. Retrotransposition is a significant source of genetic variation in eukaryotes and some transposable elements are specifically expressed under adverse environmental conditions. We present transcriptomic and phylogenetic evidence for the existence of heat stress-activated Ty1-copia-type LTR retrotransposons in the coral symbiont Symbiodinium microadriaticum. Genome-wide analyses of emergence patterns of these elements further indicate recent expansion events in the genome of S. microadriaticum. Our findings suggest that acute temperature increases can activate specific retrotransposons in the Symbiodinium genome with potential impacts on the rate of retrotransposition and the generation of genetic variation under heat stress.The ISME Journal advance online publication, 20 October 2017; doi:10.1038/ismej.2017.179.

  15. Building the crops of tomorrow: advantages of symbiont-based approaches to improving abiotic stress tolerance.

    Science.gov (United States)

    Coleman-Derr, Devin; Tringe, Susannah G

    2014-01-01

    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.

  16. 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.

  17. Microbial symbionts of honeybees: a promising tool to improve honeybee health.

    Science.gov (United States)

    Crotti, Elena; Sansonno, Luigi; Prosdocimi, Erica M; Vacchini, Violetta; Hamdi, Chadlia; Cherif, Ameur; Gonella, Elena; Marzorati, Massimo; Balloi, Annalisa

    2013-09-25

    Among pollinators, honeybees are the most important ones and exert the essential key ecosystem service of pollination for many crops, fruit and wild plants. Indeed, several crops are strictly dependent on honeybee pollination. Since few decades, honeybees are facing large-scale losses worldwide, the causes of which are found in the interaction of several biotic and abiotic factors, such as the use of pesticides, the habitat loss, the spread of pathogens and parasites and the occurrence of climate changes. Insect symbionts are emerging as a potential tool to protect beneficial insects, ameliorating the innate immune homeostasis and contributing to the general insect wellbeing. A review about the microbial symbionts associated to honeybees is here presented. The importance of the honeybee microbial commensals for the maintenance and improvement of honeybee health is discussed. Several stressors like infestations of Varroa mites and the use of pesticides can contribute to the occurrence of dysbiosis phenomena, resulting in a perturbation of the microbiocenosis established in the honeybee body. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. Cultivation of sponges, sponge cells and symbionts: achievements and future prospects.

    Science.gov (United States)

    Schippers, Klaske J; Sipkema, Detmer; Osinga, Ronald; Smidt, Hauke; Pomponi, Shirley A; Martens, Dirk E; Wijffels, René H

    2012-01-01

    Marine sponges are a rich source of bioactive compounds with pharmaceutical potential. Since biological production is one option to supply materials for early drug development, the main challenge is to establish generic techniques for small-scale production of marine organisms. We analysed the state of the art for cultivation of whole sponges, sponge cells and sponge symbionts. To date, cultivation of whole sponges has been most successful in situ; however, optimal conditions are species specific. The establishment of sponge cell lines has been limited by the inability to obtain an axenic inoculum as well as the lack of knowledge on nutritional requirements in vitro. Approaches to overcome these bottlenecks, including transformation of sponge cells and using media based on yolk, are elaborated. Although a number of bioactive metabolite-producing microorganisms have been isolated from sponges, and it has been suggested that the source of most sponge-derived bioactive compounds is microbial symbionts, cultivation of sponge-specific microorganisms has had limited success. The current genomics revolution provides novel approaches to cultivate these microorganisms. Copyright © 2012 Elsevier Ltd. All rights reserved.

  19. 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.

  20. 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.

  1. 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.

  2. 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. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  3. 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.

  4. 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

  5. Grease lubrication in rolling bearings

    CERN Document Server

    Lugt, Piet M

    2012-01-01

    The definitive book on the science of grease lubrication for roller and needle bearings in industrial and vehicle engineering. Grease Lubrication in Rolling Bearings provides an overview of the existing knowledge on the various aspects of grease lubrication (including lubrication systems) and the state of the art models that exist today. The book reviews the physical and chemical aspects of grease lubrication, primarily directed towards lubrication of rolling bearings. The first part of the book covers grease composition, properties and rheology, including thermal

  6. Improvement of bearing support lubrication

    Directory of Open Access Journals (Sweden)

    Shehovtseva E. V.

    2016-12-01

    Full Text Available Gas turbine engine bearing supports is an important part in providing product efficiency of general and special-purpose engineering industry. Attempts are being made to increase efficiency of bearing support. Such attempts are caused by the modern tendency of the development of engineering striving for compact machines and units possessing increased reliability and durability. Researches on finding discrepancies in operation of support for this purpose have been executed. The reasons of occurrence the fatigue crumbling on external bearing races at different stages development of working surface damage have been investigated. The basic constructions of support of shaft for the aviation gas turbine engine and methods of their lubrication have been considered. Shortcomings of existing methods of lubrication of bearing supports have been marked. The upgraded construction of the module of gas turbine bearing shaft, which allows to improve conditions of lubrication and bearing cooling as a result of a uniform oil feed to the contact zones of outside bearing race and rolling elements and forced oil removal from contact zones of inside bearing race and rolling elements has been suggested. The task of improving conditions of lubrication supply to an internal holder of the bearing has been solved. The developed design allows applying unconventional methods of lubrication and cooling of a bearing support. Thus it is recommended to use process of regulation of a microrough on working surfaces bearing support during grinding-in. It will allow to improve a stage grinding-in and to increase reliability and durability of bearing support.

  7. Hydrostatic and hybrid bearing design

    CERN Document Server

    Rowe, W B

    1983-01-01

    Hydrostatic and Hybrid Bearing Design is a 15-chapter book that focuses on the bearing design and testing. This book first describes the application of hydrostatic bearings, as well as the device pressure, flow, force, power, and temperature. Subsequent chapters discuss the load and flow rate of thrust pads; circuit design, flow control, load, and stiffness; and the basis of the design procedures and selection of tolerances. The specific types of bearings, their design, dynamics, and experimental methods and testing are also shown. This book will be very valuable to students of engineering des

  8. The architecture and associated fauna of Perouvianella peruviana, an endemic larger benthic foraminifera from the Cenomanian–Turonian transition interval of central Peru

    DEFF Research Database (Denmark)

    Consorti, Lorenzo; Navarro-Ramirez, Juan Pablo; Bodin, Stéphane

    2018-01-01

    -strategist foraminifera coexisted with P. peruviana. Moreover, a first description of the soritid taxa Pseudopeneroplis oyonensis n. gen., n. sp. is provided. Interestingly,the superposition of local and global environmental patterns onto the Western Peruvian shelf water masses triggered a mass development...... of the Perouvianella population coincident with Oceanic Anoxic Event 2. Conversely, the migration of foreign complex-shelled K-strategist larger benthic foraminifera from neighboring realms was inhibited.......During the Cenomanian–Turonian transition interval, larger benthic foraminifera became extinct or suffered decreases in terms of their diversity. Anoxic/dysoxic conditions of oceanic bottom water masses and potentially seawater acidification during this pivotal time also affected ecological niches...

  9. Bioerosion by microbial euendoliths in benthic foraminifera from heavy metal-polluted coastal environments of Portovesme (south-western Sardinia, Italy

    Directory of Open Access Journals (Sweden)

    A. Cherchi

    2012-11-01

    Full Text Available A monitoring survey of the coastal area facing the industrial area of Portoscuso-Portovesme (south-western Sardinia, Italy revealed intense bioerosional processes. Benthic foraminifera collected at the same depth (about 2 m but at different distances from the pollution source show extensive microbial infestation, anomalous Mg/Ca molar ratios and high levels of heavy metals in the shell associated with a decrease in foraminifera richness, population density and biodiversity with the presence of morphologically abnormal specimens. We found that carbonate dissolution induced by euendoliths is selective, depending on the Mg content and morpho-structural types of foraminiferal taxa. This study provides evidences for a connection between heavy metal dispersion, decrease in pH of the sea-water and bioerosional processes on foraminifera.

  10. Autosizing Control Panel for Needle Bearing

    OpenAIRE

    Prof.A.R.Wadhekar,; Ms Jyoti R. Rajput

    2016-01-01

    A needle roller bearing is a bearing which uses small cylindrical rollers. Bearings are used to reduce friction of any rotating surface. Needle bearings have a large surface in contact with the bearing outer surfaces as compared to ball bearings. There is less added clearance(Diameter of the shaft and the diameter of the bearing are different) so they are much compact. The structure consists of a needle cage which contains the needle rollersthemselves and an outer race (The housin...

  11. Benthic foraminifera or Ostracoda? Comparing the accuracy of palaeoenvironmental indicators from a Pleistocene lagoon of the Romagna coastal plain (Italy)

    Science.gov (United States)

    Barbieri, Giulia; Vaiani, Stefano Claudio

    2018-01-01

    Integrated analyses of multiple groups of microfossils are frequently performed to unravel the palaeoenvironmental evolution of subsurface coastal successions, where the complex interaction among several palaeoecological factors can be detected with benthic assemblages. This work investigates the palaeoenvironmental resolution potential provided by benthic foraminifera and ostracoda within a Pleistocene lagoonal succession of the Romagna coastal plain (northern Italy). Quantitative approaches and statistical techniques have been applied to both groups in order to understand the main factors that controlled the composition of assemblages and compare the palaeoecological record provided by single fossil groups. The two faunal groups are characterized by the high dominance of opportunistic species (Ammonia tepida-Ammonia parkinsoniana and Cyprideis torosa); however, detailed palaeoecological information is inferred from less common taxa. Benthic foraminiferal assemblages are mainly determined by the frequencies of abnormal individuals and species related to high concentrations of organic matter, showing two assemblages: a stressed assemblage, consistent with a brackish-water environment subject to salinity and oxygen fluctuations, and an unstressed assemblage, which indicates more stable conditions. Despite the lower number of species, ostracoda show more significant differences in terms of species composition and ecological structure between their three assemblages, formed in response to a salinity gradient and indicative of inner, central, and outer lagoon conditions. The stratigraphic distribution of ostracod assemblages shows a general transgressive-regressive trend with minor fluctuations, whereas benthic foraminifera highlight the presence of a significant palaeoenvironmental stress. In this case, the higher abundance along the stratigraphic succession, the higher differentiation of the assemblages, and the well-defined relationship between taxa and ecological

  12. Benthic foraminifera distribution in high polluted sediments from Niterói Harbor (Guanabara Bay, Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    Claudia G. Vilela

    2004-03-01

    Full Text Available Dockyards and harbors are recognized as being important locations where sediment-associated pollutants can accumulate, which constitutes an environmental risk to aquatic life due to potential uptake and accumulation of heavy metals in the biota. The aim of this paper is to assess the concentrations and the effects of some heavy metals in the benthic foraminifera assemblage in Niterói Harbor. Low concentrations in the benthic foraminifera as well as the dominance of indicative species such as Ammonia tepida, Buliminella elegantissima and Bolivina lowmani can be associated with an environment under stress. In addition, the occurrence of test abnormalities among foraminifera may represent a useful biomarker for evaluating long-term environmental impacts in a coastal region.Estaleiros e portos são locais reconhecidamente importantes onde poluentes associados a sedimentos podem acumular, constituindo um risco ambiental para a vida aquática devido ao potencial de captação e acumulação de metais pesados na biota. O propósito deste trabalho é avaliar as concentrações e os efeitos de alguns metais pesados na assembléia de foraminíferos bentônicos no Porto de Niterói. Baixas concentrações de foraminíferos bentônicos bem como a dominância de espécies indicativas como Ammonia tepida, Buliminella elegantissima e Bolivina lowmani podem ser associadas a um ambiente sob estresse. A ocorrência de anormalidades entre os foraminíferos pode representar um útil biomarcador para avaliação de impactos ambientais de longo termo em uma região costeira.

  13. Response of benthic foraminifera to 4.2 ka cooling event in the Nakdong River delta, southeast Korea

    Science.gov (United States)

    Takata, H.; Khim, B. K.; Cheong, D.; Shin, S.

    2016-02-01

    Here we report the change of benthic foraminifera in response to 4.2 ka cooling event in the Nakdong River delta (southeastern Korea). It has been known that this cooling event caused climatic deteriorations in the world, which is closely related to the decline/development of the civilizations (e.g., Kawahata et al., 2009). This event was also correlated to one of Bond Events in the North Atlantic. Because coastal sediment depositions have been influenced by both oceanographic and terrestrial climatic changes, the study may provide us clue to understand the possible teleconnection of the cooling event between the North Atlantic and the East Asian margin. We investigated fossil benthic foraminiferal faunas and planktonic/total foraminiferal ratio (P/T ratio) at two borehole cores, ND-01 and ND-02 (landward and seaward sites, respectively). Common constituents are taxa from bay to shelf environments in the East Asian margin. Biotic response of benthic foraminifera partly changed after 4.2 ka showing that Haynesina sp. A (opportunistic species?) decreased significantly at core ND-01. In addition, P/T ratio at both core sites showed temporal decline at 4.2 ka. This suggests the decreasing influence of the seawater relative to the coastal water. Holocene fluctuations of the Tsushima Warm Current, a branch of Kuroshio, flowing off the Nakdong River delta, have been documented. The decline pattern of P/T ratio in this area is similar to that of total sulfur content in Lake Tougou-ike, southwestern Japan at 4 ka which was interpreted as the influence of the small sea-level falling (Kato et al., 2003). According to the similar stratigraphic variation patterns between our and their studies, our finding suggests that this event was not regional but related to the fluctuations of the Tsushima Warm Current. Thus, biotic response of benthic foraminifera in the Nakdong River delta recorded 4.2 ka cooling event related to temporal weakening of the Tsushima Warm Current.

  14. Mid-Oligocene climate dynamics using benthic foraminifera from the Central Eastern Pacific Ocean

    Science.gov (United States)

    Zirkel, Jessica; Herrle, Jens; Pälike, Heiko; Liebrand, Diederik; Batenburg, Sietske

    2014-05-01

    The Oligocene marks the onset of major Antarctic ice sheets and hence the first step into a "icehouse" world, which continues to the present day. To understand the evolution of the Antarctic ice sheet, it is fundamental to assess and quantify changes in the ocean circulation pattern and the intensity of Pacific equatorial upwelling (PEU) since the initiation of southern hemisphere ice caps during the Eocene-Oligocene transition. It is well known that combined variations in the eccentricity, obliquity and precession of Earth's orbit influence long-term climate fluctuations, notably the build up and decay of ice volume. To unravel the importance of orbital forcing on ice volume changes and to estimate its impact on paleoproductivity in the Central Eastern Pacific Ocean, we focused on the Oi-2b event about 26.8 Ma ago, being the most important glacial episode in the mid-Oligocene (Pälike et al., 2006). We calculated benthic foraminifer accumulation rates (BFAR) to reconstruct organic matter flux to the sea floor and hence surface water productivity. Furthermore, to assess and differentiate between changes in productivity and dissolution, a planktic foraminifera-based fragmentation index (FI) was calculated. BFAR values range between 16 and 217 NBF/cm-2/kyr (average: 65 NBF/cm-2/kyr). Increased BFAR indicate phases of higher supply of organic matter to the sea floor and thus enhanced surface water productivity. Our BFAR record indicates variable but generally lower productivity conditions during the glacial event compared to pre- and post-Oi-2b conditions. However, the transition into the Oi-2b event which is documented in heavier δ18O of Cibicidoides grimsdalei (2.1 per mil to 3.0 per mil ) and Oridorsalis umbonatus (1.7 per mil and 2.6 per mil) is characterized by a higher productivity, which is also supported by the assumption of increased productivity for the onset of Oi-2b based on Δδ13C variations of planktic and benthic foraminifera from ODP Site 1218 (Wade

  15. TEST FUSION IN ADULT FORAMINIFERA: A REVIEW WITH NEW OBSERVATIONS OF AN EARLY EOCENE NUMMULITES SPECIMEN

    Science.gov (United States)

    Ferràndez-Cañadell, Carles; Briguglio, Antonino; Hohenegger, Johann; Wöger, Julia

    2015-01-01

    In foraminifera, so-called “double tests” usually arise due to abnormal growth originating mainly from twinning, but may also be caused by irregularities in the early chambers and by regeneration after test injury that modifies the direction of growth. A fourth cause of double tests has only rarely been reported: the fusion of the tests of two adult individuals. We studied an early Eocene Nummulites double test consisting of two adult individuals that fused after an extended period of independent growth. The specimen was studied using computed tomography with micrometric resolution (micro-CT) that allowed bi- and three-dimensional visualization of the internal structure. Before fusion each individual test had 30–36 chambers, which, by comparison with growth rates in recent nummulitids, implies at least three months of independent growth. After fusion, the compound test grew in two spirals that fused after about one whorl and then continued in a single spiral. To fuse their tests, either adult individuals have to be forced to do so or the allorecognition (ability to distinguish between self and another individual) mechanisms must fail. A possible explanation for the merged Nummulites tests in this study is forced fusion in attached individuals after surviving ingestion and digestion by a metazoan. Alternatively, environmental stress could lead to a failure of allorecognition mechanisms and/or foraminiferal motility. Once fused, subsequent growth seems to be determined mainly by the relative orientation of individual tests. In any case, the frequency in which adult fusion occurs remains unknown. PMID:26166916

  16. Interpreting the role of pH on stable isotopes in large benthic foraminifera

    Science.gov (United States)

    Robbins, Lisa L.; Knorr, P.O.; Wynn, J.G.; Hallock, P.; Harries, P.

    2016-01-01

    Large benthic foraminifera (LBF) are prolific producers of calcium carbonate sediments in shallow, tropical environments that are being influenced by ocean acidification (OA). Two LBF species, Amphistegina gibbosa (Order Rotaliida) with low-Mg calcite tests and Archaias angulatus (Order Miliolida) with high-Mg calcite tests, were studied to assess the effects of pH 7.6 on oxygen and carbon isotopic fractionation between test calcite and ambient seawater. The δ18O and δ13C values of terminal chambers and of whole adult tests of both species after 6 weeks were not significantly different between pH treatments of 8.0 and 7.6. However, tests of juveniles produced during the 6-week treatments showed significant differences between δ18O and δ13C values from control (pH 8.0) when compared with the treatment (pH 7.6) for both species. Although each individual's growth was photographed and measured, difficulty in distinguishing and manually extracting newly precipitated calcite from adult specimens likely confounded any differences in isotopic signals. However, juvenile specimens that resulted from asexual reproduction that occurred during the experiments did not contain old carbonate that could confound the new isotopic signals. These data reveal a potential bias in the design of OA experiments if only adults are used to investigate changes in test chemistries. Furthermore, the results reaffirm that different calcification mechanisms in these two foraminiferal orders control the fractionation of stable isotopes in the tests and will reflect decreasing pH in seawater somewhat differently. .

  17. Annual and seasonal distribution of intertidal foraminifera and stable carbon isotope geochemistry, Bandon Marsh, Oregon, USA

    Science.gov (United States)

    Milker, Yvonne; Horton, Benjamin; Vane, Christopher; Engelhart, Simon; Nelson, Alan R.; Witter, Robert C.; Khan, Nicole S.; Bridgeland, William

    2014-01-01

    We investigated the influence of inter-annual and seasonal differences on the distribution of live and dead foraminifera, and the inter-annual variability of stable carbon isotopes (d13C), total organic carbon (TOC) values and carbon to nitrogen (C/N) ratios in bulk sediments from intertidal environments of Bandon Marsh (Oregon, USA). Living and dead foraminiferal species from 10 stations were analyzed over two successive years in the summer (dry) and fall (wet) seasons. There were insignificant inter-annual and seasonal variations in the distribution of live and dead species. But there was a noticeable decrease in calcareous assemblages (Haynesina sp.) between live populations and dead assemblages, indicating that most of the calcareous tests were dissolved after burial; the agglutinated assemblages were comparable between constituents. The live populations and dead assemblages were dominated by Miliammina fusca in the tidal flat and low marsh, Jadammina macrescens, Trochammina inflata and M. fusca in the high marsh, and Trochamminita irregularis and Balticammina pseudomacrescens in the highest marsh to upland. Geochemical analyses (d13C, TOC and C/N of bulk sedimentary organic matter) show no significant influence of inter-annual variations but a significant correlation of d13C values (R = 20.820, p , 0.001), TOC values (R = 0.849, p , 0.001) and C/N ratios (R = 0.885, p , 0.001) to elevation with respect to the tidal frame. Our results suggest that foraminiferal assemblages and d13C and TOC values, as well as C/N ratios, in Bandon Marsh are useful in reconstructing paleosea-levels on the North American Pacific coast.

  18. Multiproxies (benthic foraminifera, ostracods and biopolymers approach applied to identify the environmental partitioning of the Guadiana River Estuary (Iberian Peninsula

    Directory of Open Access Journals (Sweden)

    Lazaro Luiz Mattos Laut

    2016-04-01

    Full Text Available The Guadiana River is the fourth longest river in Europe and is a natural frontier between southern Portugal and Spain. This river was historically used to transport minerals exploited in the region since the Roman Empire and therefore suffered human interventions that have been intensified after the industrial revolution. The Guadiana River has in its limits the Guadiana Valley Natural Park, which is of great value for the Conservation of Geobiodiversity. This study mainly aims to identify zones with the environmental characteristics in the estuarine area of the Guadiana River based on the distribution and ecology of microorganisms (ostracods and foraminifera associated with physicochemical parameters and sedimentological and geochemical (carbohydrate, lipid, protein, total organic carbon and total sulfur data. Fifty-five foraminifera taxa were identified along the estuary with dominance of Ammonia tepida and Miliammina fusca and 13 ostracods taxa with dominance Leptocythere lacertosa and Loxoconcha elliptica. Detrended correspondence analysis (DCA performed using biotic and abiotic variables indicated that pH, grain size, total organic carbon (TOC and lipids were the most influent factors in the distribution of these organisms. Four zones were identified in the Guadiana River estuary: i Low estuary - region with the largest marine influence with sandy sediment, higher salinity and total sulfur and mainly represented by the dominance of estuarine species of foraminifera (Ammonia tepida and Cribroelphidium vadescens and by the ostracods (Darwinula stevensoni, Semicytherura sulcata and Urocythereis oblonga; ii Intermediate estuary - region characterized by neutral pH and sandy sediment enriched in carbohydrates; this region is characterized by the presence of the ostracods species Cytherois fischeri and Neocytherideis subulata and by calcareous and agglutinated species in foraminiferal assemblages; iii Upper estuary - silt, high TOC, proteins and

  19. Taxonomy and distribution of benthic foraminifera from the sediments of Palk Strait, Tamil Nadu, east coast of India

    Digital Repository Service at National Institute of Oceanography (India)

    Gandhi, S.; Rajamanickam, G.V.; Nigam, R.

    d'Orbigny var. porrecta Brady, 1884, Challenger Expedition Reports, Zoology, v.9, pts.2, p.304, p.43, figs.4a-b. Textularia porrecta (Brady, 1884) - Yassini and Jones, 1995, p.76, pl.7, figs.104 - 110. - Rao, 1998, p.GO, pl.6, figs.4-5. Hypotype... 'Challenger' during the year 1873-1876. Soc. Econ. Paleont. Miner. Spec. Pub!. Bhalla, S.N. 1968. Recent foraminifera from Visakhapatnam beaeh sands and its relation to the known foramgeographical provinces in the Indian ocean. Bull. Nat. Inst. Sci. India...

  20. Effect of varying frontal systems on stable oxygen and carbon isotopic compositions of modern planktic foraminifera of Southern Ocean

    Digital Repository Service at National Institute of Oceanography (India)

    Tiwari, M.; Mohan, R.; Meloth, T.; Naik, S.S.; Sudhakar, M.

    were filtered, dried and individual planktic foraminifera picked. Dried sediment samples were then soaked in water and treated with sodium hexametaphos- phate (calgon powder) and hydrogen peroxide (H 2 O 2 ) to dissociate the material and oxidize... decline further and the δ 18 O of N. pachyderma attains a maximum value of 1.93‰. The carbon isotopic values are governed by the iso- topic composition of the dissolved bicarbonate (HCO – 3 ), which in turn is modulated by the productivity and mix...

  1. Bathymetric preference of four major genera of rectilinear benthic foraminifera within oxygen minimum zone in Arabian Sea off central west coast of India.

    Digital Repository Service at National Institute of Oceanography (India)

    Mazumder, A.; Nigam, R.

    species, including two species of Bolivina and a single species of Uvigerina, with the bathymetrical variation from the northern Gulf of Mexico. But there is no attempt to correlate the total population of any important genus of rectilinear foraminifera...–900. Malakoff D 1998 Death by suffocation in the Gulf of Mexico; Science 281 190–192. Mallon J, Glock N and Scho¨nfeld J 2012 The response of benthic foraminifera to low-oxygen conditions of the Peruvian oxygen minimum zone; In: ANOXIA: Evidence for eukaryote...

  2. A transgressive Santonian-Campanian boundary sequence revisited - High resolution planktonic and benthic foraminifera stratigraphy of the Schattau section, Northern Calcareous Alps.

    Science.gov (United States)

    Wolfgring, Erik; Wagreich, Michael; Summesberger, Herbert; Kroh, Andreas

    2016-04-01

    The Schattau section is part of the Austrian Gosau Group, Northern Calcareous Alps. We record a Santonian to early Campanian transgressive sequence. Previous investigations already provide a biostratigraphic framework; a multidisciplinary study to reveal the local stratigraphy and palaeoenvironmental properties: Planktonic foraminifera, calcareous nannoplankton, ammonite, echinoid and crinoid biostratigraphy data suggest a Santonian to earliest Campanian age for this section (see Wagreich et al., 2009). This work aims at a high resolution assessment of foraminiferal assemblages recorded from a time interval that has undergone significant palaeoenvironmental changes. The Santonian Hochmoos Formation, with the Sandkalkbank Member representing it's topmost subunit, is overlain by the Santonian to Campanian Bibereck Formation. While The Hochmoos Formation records a shallowing succession that finds the Sandkalkbank Member (representing very shallow conditions, sometimes sub aerial exposure) at its top. The overlying Bibereck Formation records a distinct deepening trend displaying increasingly marine, neritic to outer neritic conditions. The stratigraphically older subunits of the Schattau sections are characterised by abundant larger benthic foraminifera (Nummofallotia cretacea), miliolid foraminifera (Quinqueloculina spp, Spiroloculina fassistomata) as well as rotaliid foraminifera (Hoeglundia spp., Gavellina spp.). The Sandkalkbank member marks the end of the shallow water sequence recorded from foraminifera assemblages at the Schattau section. Up section communities are characterised by increasing share of planktonic foraminifera. Biostratigraphic marker fossils like Dicarinella asymetrica and Sigalia sp. (decoratissima?) were identified and indicate a Santonian age for the Bibereck Formation. The appearance of Globotruncanita elevata and disappearance of D. asymetrica and Sigalia sp. Suggests an early Campanian age for the topmost part of the Schattau section

  3. Application of individual foraminifera Mg/Ca and δ18O analyses for paleoceanographic reconstructions in the Bay of Bengal and other active depositional environments

    Science.gov (United States)

    Fritz-Endres, T.; Dekens, P.; Fehrenbacher, J. S.; Spero, H. J.; Stine, A.

    2017-12-01

    Paleoceanographic research traditionally focuses on regions where sediment deposition is minimally affected by transport. However, sediment fans near tectonically active regions provide an opportunity to link oceanographic climate to terrestrial processes. Sediment cores recovered during IODP Expedition 354 in the Bay of Bengal include hemipelagic sections that record the history of tectonic uplift and the development of the Indian Monsoon through the last 10 Ma. Although these cores provide a unique opportunity to link marine and terrestrial climate, the complex depositional environment requires that the source of foraminifera is carefully considered before using these proxies to reconstruct oceanographic conditions. Foraminifera in Bengal Fan sediments may have been transported via turbidity currents from the northern Bay of Bengal, where the seasonal variability of SST and SSS is larger compared to the southern Bay of Bengal. We measured single Globigerinoides sacculifer Mg/Ca and δ18O from mudline samples of IODP Site U1454 (8.4°N, 85.5°E, 3721 m water depth) near the modern active channel and Site U1449 (8.4°N, 88.7°E, 3653 m water depth) far from channel activity. We compare these sites to single G. sacculifer from the core-top sample of Site 342KL (20.6°N, 90.1°E, 1256 m water depth) located on the continental shelf. Each foraminifera lives 2-4 weeks and the distribution of 60 to 80 data points reflects the seasonal range of SST and SSS at the location where the foraminifera calcified. Measurements in foraminifera from Site U1449 (away from active channel) are statistically different from the site in the northern Bay of Bengal and more consistent with local conditions. Conversely, foraminifera from the site near the active channel reflect a combined signal of local conditions recorded from the site far from channel activity and those recorded from the continental shelf. This suggests a portion of foraminifera from the active channel site have been

  4. Fungal Symbionts of the Spruce Bark Beetle Synthesize the Beetle Aggregation Pheromone 2-Methyl-3-buten-2-ol.

    Science.gov (United States)

    Zhao, Tao; Axelsson, Karolin; Krokene, Paal; Borg-Karlson, Anna-Karin

    2015-09-01

    Tree-killing bark beetles depend on aggregation pheromones to mass-attack their host trees and overwhelm their resistance. The beetles are always associated with phytopathogenic ophiostomatoid fungi that probably assist in breaking down tree resistance, but little is known about if or how much these fungal symbionts contribute to the beetles' aggregation behavior. In this study, we determined the ability of four major fungal symbionts of the spruce bark beetle Ips typographus to produce beetle aggregation pheromones. The fungi were incubated on Norway spruce Picea abies bark, malt agar, or malt agar amended with 0.5% (13)C glucose. Volatiles present in the headspace of each fungus were analyzed for 7 days after incubation using a SPME autosampler coupled to a GC/MS. Two Grosmannia species (G. penicillata and G. europhioides) produced large amounts of 2-methyl-3-buten-2-ol (MB), the major component in the beetles' aggregation pheromone blend, when growing on spruce bark or malt agar. Grosmannia europhioides also incorporated (13)C glucose into MB, demonstrating that the fungi can synthesize MB de novo using glucose as a carbon source. This is the first clear evidence that fungal symbionts of bark beetles can produce components in the aggregation pheromone blend of their beetle vectors. This provides new insight into the possible ecological roles of fungal symbionts in bark beetle systems and may deepen our understanding of species interactions and coevolution in these important biological systems.

  5. Distinct effects of the nephridial symbionts Verminephrobacter and Candidatus Nephrothrix on reproduction and maturation of its earthworm host Eisenia andrei

    DEFF Research Database (Denmark)

    Viana, Flavia; Paz, Laura-Carlota; Methling, Karen

    2018-01-01

    evidence for a beneficial role of Ca. Nephrothrix in earthworms. Riboflavin content in cocoons and whole earthworms was unaffected by the presence or absence of nephridial symbionts, suggesting that nutritional supplementation with this vitamin does not play a major role in this symbiosis....

  6. Expression patterns of mRNAs for methanotrophy and thiotrophy in symbionts of the hydrothermal vent mussel Bathymodiolus puteoserpentis

    Science.gov (United States)

    Wendeberg, Annelie; Zielinski, Frank U; Borowski, Christian; Dubilier, Nicole

    2012-01-01

    The hydrothermal vent mussel Bathymodiolus puteoserpentis (Mytilidae) from the Mid-Atlantic Ridge hosts symbiotic sulfur- and methane-oxidizing bacteria in its gills. In this study, we investigated the activity and distribution of these two symbionts in juvenile mussels from the Logatchev hydrothermal vent field (14°45′N Mid-Atlantic Ridge). Expression patterns of two key genes for chemosynthesis were examined: pmoA (encoding subunit A of the particulate methane monooxygenase) as an indicator for methanotrophy, and aprA (encoding the subunit A of the dissimilatory adenosine-5′-phosphosulfate reductase) as an indicator for thiotrophy. Using simultaneous fluorescence in situ hybridization (FISH) of rRNA and mRNA we observed highest mRNA FISH signals toward the ciliated epithelium where seawater enters the gills. The levels of mRNA expression differed between individual specimens collected in a single grab from the same sampling site, whereas no obvious differences in symbiont abundance or distribution were observed. We propose that the symbionts respond to the steep temporal and spatial gradients in methane, reduced sulfur compounds and oxygen by modifying gene transcription, whereas changes in symbiont abundance and distribution take much longer than regulation of mRNA expression and may only occur in response to long-term changes in vent fluid geochemistry. PMID:21734728

  7. 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.

  8. Meta-analysis reveals host-dependent nitrogen recycling as a mechanism of symbiont control in Aiptasia

    KAUST Repository

    Cui, Guoxin

    2018-02-22

    The metabolic symbiosis with photosynthetic algae of the genus Symbiodinium allows corals to thrive in the oligotrophic environments of tropical seas. Many aspects of this relationship have been investigated using transcriptomic analyses in the emerging model organism Aiptasia. However, previous studies identified thousands of putatively symbiosis-related genes, making it difficult to disentangle symbiosis-induced responses from undesired experimental parameters. Using a meta-analysis approach, we identified a core set of 731 high-confidence symbiosis-associated genes that reveal host-dependent recycling of waste ammonium and amino acid synthesis as central processes in this relationship. Combining transcriptomic and metabolomic analyses, we show that symbiont-derived carbon enables host recycling of ammonium into nonessential amino acids. We propose that this provides a regulatory mechanism to control symbiont growth through a carbon-dependent negative feedback of nitrogen availability to the symbiont. The dependence of this mechanism on symbiont-derived carbon highlights the susceptibility of this symbiosis to changes in carbon translocation, as imposed by environmental stress.

  9. Permanent-Magnet Meissner Bearing

    Science.gov (United States)

    Robertson, Glen A.

    1994-01-01

    Permanent-magnet meissner bearing features inherently stable, self-centering conical configuration. Bearing made stiffer or less stiff by selection of magnets, springs, and spring adjustments. Cylindrical permanent magnets with axial magnetization stacked coaxially on rotor with alternating polarity. Typically, rare-earth magnets used. Magnets machined and fitted together to form conical outer surface.

  10. Superconducting bearings for flywheel applications

    DEFF Research Database (Denmark)

    Abrahamsen, A.B.

    2001-01-01

    A literature study on the application of superconducting bearings in energy storage flywheel systems. The physics of magnetic levitation and superconductors are presented in the first part of the report, followed by a discussion of the literature found onthe applications of superconducting bearings...

  11. What about the Javan Bear?

    NARCIS (Netherlands)

    Jentink, F.A.

    1898-01-01

    The other day I read in a dutch popular periodical a paper dealing with the different species of Bears and their geographical distribution. To my great surprise the Malayan Bear was mentioned from Java: the locality Java being quite new to me I wrote to the author of that paper and asked him some

  12. 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

  13. Nonlinear control of magnetic bearings

    Science.gov (United States)

    Pradeep, A. K.; Gurumoorthy, R.

    1994-01-01

    In this paper we present a variety of nonlinear controllers for the magnetic bearing that ensure both stability and robustness. We utilize techniques of discontinuous control to design novel control laws for the magnetic bearing. We present in particular sliding mode controllers, time optimal controllers, winding algorithm based controllers, nested switching controllers, fractional controllers, and synchronous switching controllers for the magnetic bearing. We show existence of solutions to systems governed by discontinuous control laws, and prove stability and robustness of the chosen control laws in a rigorous setting. We design sliding mode observers for the magnetic bearing and prove the convergence of the state estimates to their true values. We present simulation results of the performance of the magnetic bearing subject to the aforementioned control laws, and conclude with comments on design.

  14. Flywheel Challenge: HTS Magnetic Bearing

    International Nuclear Information System (INIS)

    Werfel, F N; Floegel-Delor, U; Riedel, T; Rothfeld, R; Wippich, D; Goebel, B

    2006-01-01

    A 200 mm cylindrical engineering prototype high temperature superconducting (HTS) was designed and fabricated. Measurements show that the 17 kg PM rotor can suspend safely 1000 kg in axial direction and 470 kg radially. The rationale for the bearing performance is to stabilize a 400 kg rotor of a new compact 5 kWh/280 kW flywheel energy storage system (COM - FESS). Measurements of the magnetic bearing force, stiffness and drag-torque are presented indicated the successful targeting a milestone in the HTS bearing technology. The influence of the PM configuration and the YBCO temperature on the bearing performance was experimentally studied, providing high-force or high-stiffness behaviour. The axial stiffness 5 kN/mm at 0.5 mm displacement is the highest value of a HTS bearing we know

  15. Inherited microbial symbionts increase herbivore abundances and alter arthropod diversity on a native grass.

    Science.gov (United States)

    Faeth, Stanley H; Shochat, Eyal

    2010-05-01

    Some microbial symbionts of plants are maternally inherited and thus functionally increase genetic and phenotypic variation within plant populations. This variation, coupled with that of the host plant and environment, may alter abundances, diversity, and trophic structure of associated plant and animal communities. Fungal endophytes in the genus Neotyphodium are vertically transmitted, asexual microbial symbionts of grasses that remain asymptomatic and rely upon their hosts for resources and transmission via seeds, often providing benefits to their hosts, including protection against herbivores. Endophyte infections may influence associated arthropod communities in agronomic grasses, but the long-term effects of endophytes and variation in host genotype and resource availability on arthropod communities in native grass populations are unknown. We conducted a long-term field experiment with four maternal genotypes of an infected (E+) native grass (Festuca arizonica) from whence the endophyte was experimentally removed (E-) and water availability was controlled, to test the effects of infection, plant genotype, and resources on abundances, biomass, diversity (richness and evenness), and trophic structure of the arthropod community. Generally, E+ grasses harbored more arthropods, including more herbivores, predators, and detritivores, suggesting that the effects of endophytes cascaded upward through trophic levels in terms of abundances, at least in early ontogeny of the host. That E+ plants harbored more herbivorous insects than E- plants suggests that infection does not increase but instead decreases resistance to herbivores, contrary to prevailing concepts of endophytes as defensive mutualists. Infection did not alter overall species richness of the arthropod community or richness of herbivores but reduced natural enemy richness, especially that of parasites, and increased richness of detritivores. Reduced richness and shifts in evenness of natural enemies on E

  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. Evidence for cascades of perturbation and adaptation in the metabolic genes of higher termite gut symbionts.

    Science.gov (United States)

    Zhang, Xinning; Leadbetter, Jared R

    2012-01-01

    Termites and their gut microbes engage in fascinating dietary mutualisms. Less is known about how these complex symbioses have evolved after first emerging in an insect ancestor over 120 million years ago. Here we examined a bacterial gene, formate dehydrogenase (fdhF), that is key to the mutualism in 8 species of "higher" termite (members of the Termitidae, the youngest and most biomass-abundant and species-rich termite family). Patterns of fdhF diversity in the gut communities of higher termites contrasted strongly with patterns in less-derived (more-primitive) insect relatives (wood-feeding "lower" termites and roaches). We observed phylogenetic evidence for (i) the sweeping loss of several clades of fdhF that may reflect extinctions of symbiotic protozoa and, importantly, bacteria dependent on them in the last common ancestor of all higher termites and (ii) a radiation of genes from the (possibly) single allele that survived. Sweeping gene loss also resulted in (iii) the elimination of an entire clade of genes encoding selenium (Se)-independent enzymes from higher termite gut communities, perhaps reflecting behavioral or morphological innovations in higher termites that relaxed preexisting environmental limitations of Se, a dietary trace element. Curiously, several higher termite gut communities may have subsequently reencountered Se limitation, reinventing genes for Se-independent proteins via convergent evolution. Lastly, the presence of a novel fdhF lineage within litter-feeding and subterranean higher (but not other) termites may indicate recent gene "invasion" events. These results imply that cascades of perturbation and adaptation by distinct evolutionary mechanisms have impacted the evolution of complex microbial communities in a highly successful lineage of insects. Since patterns of relatedness between termite hosts are broadly mirrored by the relatedness of their symbiotic gut microbiota, coevolution between hosts and gut symbionts is rightly

  18. Can Foraminifera be used to Identify Storm Deposits in Shallow-Water Tropical Reef Settings?: Examining the Impact of Cyclone Hamish on the Foraminiferal Assemblages of Heron Island, Great Barrier Reef, Australia

    Science.gov (United States)

    Strotz, L. C.; Mamo, B. L.

    2009-12-01

    Foraminifera (marine microfossils) represent a valuable tool in identifying significant storm events in the geological past. Much of the previous work in this area however, has concentrated on temperate settings and marsh deposits. Little work has focused on tropical marine settings and no studies have looked to identify distinct foraminiferal assemblages associated with cyclone events in tropical reef settings in the South-West Pacific. In April 2008, samples were collected from the reef flat surrounding Heron Island as part of a study of foraminiferal biodiversity. On March 9th 2009, Cyclone Hamish, a Category 5 cyclone and the most significant cyclone event, in terms of impact and damage, to occur in the southern Great Barrier Reef region in over 30 years, passed in close proximity to Heron Island. With a pre-cyclone baseline collected less than 1 year previous, this presented an ideal opportunity to recollect, with the aim to determining if a discernable cyclone generated deposit could be identified. A distinct difference in composition or character of the foraminiferal assemblage identified in the pre- and post-cyclone samples could be directly attributed to the cyclone and would represent a ‘fingerprint assemblage’. This would provide a mechanism for determining cyclonic activity in the sub-recent and geological past for both the Great Barrier Reef region as well as throughout the South-west Pacific. Analysis of the total foraminiferal assemblage in the two sample lots reveals little difference between the pre- and post-cyclone assemblage. In both cases, the assemblage is dominated by the same two epiphytic taxa, Calcarina hispida Brady and Baculogypsina sphaerulata (Parker and Jones). No taxa are restricted to either pre- or post-cyclone samples and the post-cyclone assemblage bears no resemblance to the assemblage recovered from samples collected in the inter-reef channels. This suggests that the cyclone is only mobilising and redepositing material on

  19. Antagonistic bacterial interactions help shape host-symbiont dynamics within the fungus-growing ant-microbe mutualism.

    Directory of Open Access Journals (Sweden)

    Michael Poulsen

    2007-09-01

    Full Text Available Conflict within mutually beneficial associations is predicted to destabilize relationships, and theoretical and empirical work exploring this has provided significant insight into the dynamics of cooperative interactions. Within mutualistic associations, the expression and regulation of conflict is likely more complex than in intraspecific cooperative relationship, because of the potential presence of: i multiple genotypes of microbial species associated with individual hosts, ii multiple species of symbiotic lineages forming cooperative partner pairings, and iii additional symbiont lineages. Here we explore complexity of conflict expression within the ancient and coevolved mutualistic association between attine ants, their fungal cultivar, and actinomycetous bacteria (Pseudonocardia. Specifically, we examine conflict between the ants and their Pseudonocardia symbionts maintained to derive antibiotics against parasitic microfungi (Escovopsis infecting the ants' fungus garden. Symbiont assays pairing isolates of Pseudonocardia spp. associated with fungus-growing ants spanning the phylogenetic diversity of the mutualism revealed that antagonism between strains is common. In contrast, antagonism was substantially less common between more closely related bacteria associated with Acromyrmex leaf-cutting ants. In both experiments, the observed variation in antagonism across pairings was primarily due to the inhibitory capabilities and susceptibility of individual strains, but also the phylogenetic relationships between the ant host of the symbionts, as well as the pair-wise genetic distances between strains. The presence of antagonism throughout the phylogenetic diversity of Pseudonocardia symbionts indicates that these reactions likely have shaped the symbiosis from its origin. Antagonism is expected to prevent novel strains from invading colonies, enforcing single-strain rearing within individual ant colonies. While this may align ant

  20. The inadequacy of morphology for species and genus delineation in microbial eukaryotes: an example from the parabasalian termite symbiont coronympha.

    Science.gov (United States)

    Harper, James T; Gile, Gillian H; James, Erick R; Carpenter, Kevin J; Keeling, Patrick J

    2009-08-11

    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. 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. 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 Coronympha, while the single recognized species of Coronympha octonaria inhabiting these four

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

    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

  3. Laccase detoxification mediates the nutritional alliance between leaf-cutting ants and fungus-garden symbionts

    DEFF Research Database (Denmark)

    De Fine Licht, Henrik; Schiøtt, Morten; Rogowska-Wrzesinska, Adelina

    2013-01-01

    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...

  4. 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...... 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...

  5. 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.

  6. Phosphorus sequestration in the form of polyphosphate by microbial symbionts in marine sponges.

    Science.gov (United States)

    Zhang, Fan; Blasiak, Leah C; Karolin, Jan O; Powell, Ryan J; Geddes, Chris D; Hill, Russell T

    2015-04-07

    Marine sponges are major habitat-forming organisms in coastal benthic communities and have an ancient origin in evolution history. Here, we report significant accumulation of polyphosphate (polyP) granules in three common sponge species of the Caribbean coral reef. The identity of the polyP granules was confirmed by energy-dispersive spectroscopy (EDS) and by the fluorescence properties of the granules. Microscopy images revealed that a large proportion of microbial cells associated with sponge hosts contained intracellular polyP granules. Cyanobacterial symbionts cultured from sponges were shown to accumulate polyP. We also amplified polyphosphate kinase (ppk) genes from sponge DNA and confirmed that the gene was expressed. Based on these findings, we propose here a potentially important phosphorus (P) sequestration pathway through symbiotic microorganisms of marine sponges. Considering the widespread sponge population and abundant microbial cells associated with them, this pathway is likely to have a significant impact on the P cycle in benthic ecosystems.

  7. Comparative sequence analysis of bacterial symbionts from the marine sponges Geodia cydonium and Ircinia muscarum.

    Science.gov (United States)

    Zuppa, Antonio; Costantini, Susan; Costantini, Maria

    2014-01-01

    Marine sponges (Porifera) live in a symbiotic relationship with microorganisms, primarily bacteria. Recently, several studies indicated that sponges are the most prolific source of biologically-active compounds produced by symbiotic microorganisms rather than by the sponges themselves. In the present study we characterized the bacterial symbionts from two Demospongiae, Ircinia muscarum and Geodia cydonium. We amplified 16S rRNA by PCR, using specific bacterial-primers. The phylogenetic analysis revealed the presence of nine bacterial clones from I. muscarum and ten from G. cydonium. In particular, I. muscarum resulted enriched in Bacillus species and G. cydonium in Proteobacterium species. Since these bacteria were able to produce secondary metabolites with potential biotechnological and biopharmaceutical applications, we hypothesized that I. muscarum and G. cydonium could be a considered as a "gold mine" of natural products.

  8. Synchronized sexuality of an algal symbiont and its dinoflagellate host, Peridinium balticum (Levander) Lemmermann.

    Science.gov (United States)

    Chesnick, J M; Cox, E R

    1987-01-01

    We report synchronized sexual reproduction between the chlorophyll c-containing algal endosymbiont and its dinoflagellate host in Peridinium balticum (Pyrrhophyta). This organism's importance lies in that it may represent an intermediate between primitive non-photosynthetic and advanced photosynthetic dinoflagellates. Fusion of the endosymbionts and their nuclei occurred concomitantly with syngamy of the host gametes. Significant morphological changes, including condensation of chromatin and crystalline rod formation, occurred in the symbiont nucleus during zygote development. These observations provide evidence that the endosymbiotic nucleus is not passive in sexual processes, as opposed to its reported passive state during mitosis. P. balticum may not only represent an intermediate in the evolution of chloroplast acquisition by dinoflagellates, but also, an intermediate in the evolution of the peridinian dinoflagellate sexual life history.

  9. 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.

  10. Phylogeny and Phylogeography of Rhizobial Symbionts Nodulating Legumes of the Tribe Genisteae

    Directory of Open Access Journals (Sweden)

    Tomasz Stępkowski

    2018-03-01

    Full Text Available The legume tribe Genisteae comprises 618, predominantly temperate species, showing an amphi-Atlantic distribution that was caused by several long-distance dispersal events. Seven out of the 16 authenticated rhizobial genera can nodulate particular Genisteae species. Bradyrhizobium predominates among rhizobia nodulating Genisteae legumes. Bradyrhizobium strains that infect Genisteae species belong to both the Bradyrhizobium japonicum and Bradyrhizobium elkanii superclades. In symbiotic gene phylogenies, Genisteae bradyrhizobia are scattered among several distinct clades, comprising strains that originate from phylogenetically distant legumes. This indicates that the capacity for nodulation of Genisteae spp. has evolved independently in various symbiotic gene clades, and that it has not been a long-multi-step process. The exception is Bradyrhizobium Clade II, which unlike other clades comprises strains that are specialized in nodulation of Genisteae, but also Loteae spp. Presumably, Clade II represents an example of long-lasting co-evolution of bradyrhizobial symbionts with their legume hosts.

  11. 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.

  12. 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

    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......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...

  13. Diversity and genomes of uncultured microbial symbionts in the termite gut.

    Science.gov (United States)

    Hongoh, Yuichi

    2010-01-01

    Termites play a key role in the global carbon cycle as decomposers. Their ability to thrive solely on dead plant matter is chiefly attributable to the activities of gut microbes, which comprise protists, bacteria, and archaea. Although the majority of the gut microbes are as yet unculturable, molecular analyses have gradually been revealing their diversity and symbiotic mechanisms. Culture-independent studies indicate that a single termite species harbors several hundred species of gut microbes unique to termites, and that the microbiota is consistent within a host termite species. To elucidate the functions of these unculturable symbionts, environmental genomics has recently been applied. Particularly, single-species-targeting metagenomics has provided a breakthrough in the understanding of symbiotic roles, such as the nitrogen fixation, of uncultured, individual microbial species. A combination of single-species-targeting metagenomics, conventional metagenomics, and metatranscriptomics should be a powerful tool to dissect this complex, multi-layered symbiotic system.

  14. Heavy metals in benthic foraminifera from the highly polluted sediments of the Naples harbour (Southern Tyrrhenian Sea, Italy).

    Science.gov (United States)

    Rumolo, Paola; Manta, Daniela Salvagio; Sprovieri, Mario; Coccioni, Rodolfo; Ferraro, Luciana; Marsella, Ennio

    2009-10-15

    A systematic investigation evaluated the concentrations of a selected number of trace elements (Cd, Co, Cu, Li, Ni, Pb, V and Zn) in carbonates of the benthic foraminifera Ammonia tepida collected from surface sediments of the highly polluted harbour of Naples. Application of cleaning procedures, combined with Scanning Electron Microscopy investigation (SEM) of the analysed shells allowed reliable quantification of the elements in the carbonate lattice. Adoption of biogenic carbonate/seawater distribution coefficients reported in the literature provided the ranges of variability of total dissolved trace elements in the studied marine environment. Very high concentrations of Zn, Cd, and Cu calculated in seawater (from 100 to 10,000 times higher than those reported for uncontaminated Mediterranean seawaters) testify to intense effects of anthropogenic impact on the harbour mainly related to the industrial and commercial activities carried out in the neighbouring area. The ensemble of the obtained results emphasizes the high potential of measurements of trace elements in the biogenic carbonates of benthic foraminifera as tracers of anthopogenic pollution of seawater and reliable proxies of potentially bioavailable forms (as free ions and/or more labile organic complexes) of seawater dissolved metals.

  15. Decalcification and survival of benthic foraminifera under the combined impacts of varying pH and salinity.

    Science.gov (United States)

    Charrieau, Laurie M; Filipsson, Helena L; Nagai, Yukiko; Kawada, Sachiko; Ljung, Karl; Kritzberg, Emma; Toyofuku, Takashi

    2018-04-03

    Coastal areas display natural large environmental variability such as frequent changes in salinity, pH, and carbonate chemistry. Anthropogenic impacts - especially ocean acidification - increase this variability, which may affect the living conditions of coastal species, particularly, calcifiers. We performed culture experiments on living benthic foraminifera to study the combined effects of lowered pH and salinity on the calcification abilities and survival of the coastal, calcitic species Ammonia sp. and Elphidium crispum. We found that in open ocean conditions (salinity ∼35) and lower pH than usual values for these species, the specimens displayed resistance to shell (test) dissolution for a longer time than in brackish conditions (salinity ∼5 to 20). However, the response was species specific as Ammonia sp. specimens survived longer than E. crispum specimens when placed in the same conditions of salinity and pH. Living, decalcified juveniles of Ammonia sp. were observed and we show that desalination is one cause for the decalcification. Finally, we highlight the ability of foraminifera to survive under Ω calc  salinity and [Ca 2+ ] as building blocks are crucial for the foraminiferal calcification process. Copyright © 2018 Elsevier Ltd. All rights reserved.

  16. Heavy metals in benthic foraminifera from the highly polluted sediments of the Naples harbour (Southern Tyrrhenian Sea, Italy)

    International Nuclear Information System (INIS)

    Rumolo, Paola; Manta, Daniela Salvagio; Sprovieri, Mario; Coccioni, Rodolfo; Ferraro, Luciana; Marsella, Ennio

    2009-01-01

    A systematic investigation evaluated the concentrations of a selected number of trace elements (Cd, Co, Cu, Li, Ni, Pb, V and Zn) in carbonates of the benthic foraminifera Ammonia tepida collected from surface sediments of the highly polluted harbour of Naples. Application of cleaning procedures, combined with Scanning Electron Microscopy investigation (SEM) of the analysed shells allowed reliable quantification of the elements in the carbonate lattice. Adoption of biogenic carbonate/seawater distribution coefficients reported in the literature provided the ranges of variability of total dissolved trace elements in the studied marine environment. Very high concentrations of Zn, Cd, and Cu calculated in seawater (from 100 to 10,000 times higher than those reported for uncontaminated Mediterranean seawaters) testify to intense effects of anthropogenic impact on the harbour mainly related to the industrial and commercial activities carried out in the neighbouring area. The ensemble of the obtained results emphasizes the high potential of measurements of trace elements in the biogenic carbonates of benthic foraminifera as tracers of anthopogenic pollution of seawater and reliable proxies of potentially bioavailable forms (as free ions and/or more labile organic complexes) of seawater dissolved metals.

  17. Possible roles of pH, temperature, and partial dissolution in determining boron concentration and isotopic composition in planktonic foraminifera

    Science.gov (United States)

    Wara, M.W.; Delaney, M.L.; Bullen, T.D.; Ravelo, A.C.

    2003-01-01

    We present the first continuous records from 0 to 5 Ma (in 0.333 m.y. integrated time steps) of paired boron/calcium (B/Ca) ratios and boron isotopes (??11B) in the planktonic foraminifera Globogerinoides sacculifer (without sacc) from a site in the western equatorial Pacific Ocean (Ocean Drilling Program Site 806). These measurements, the first made in conjunction with calcification temperature (magnesium/calcium ratios) and average shell mass measurements, indicate that pH is not the sole environmental variable controlling B in planktonic foraminiferal calcite. Our data are consistent with calcification temperature exerting a primary control on B concentration and isotopic composition in planktonic foraminifera. If so, calcification temperature must be taken into account if pH for past oceans and atmospheric pCO2 are to be estimated from B isotope measurements in foraminiferal calcite. Doing so will substantially increase the uncertainty of PH estimates. Although this work was designed as a temporal study, its results define new aspects of calibrating the ??11B paleo-pH tracer. Copyright 2003 by the American Geophysical Union.

  18. Link between light-triggered Mg-banding and chamber formation in the planktic foraminifera Neogloboquadrina dutertrei

    Science.gov (United States)

    Fehrenbacher, Jennifer S.; Russell, Ann D.; Davis, Catherine V.; Gagnon, Alexander C.; Spero, Howard J.; Cliff, John B.; Zhu, Zihua; Martin, Pamela

    2017-05-01

    The relationship between seawater temperature and the average Mg/Ca ratios in planktic foraminifera is well established, providing an essential tool for reconstructing past ocean temperatures. However, many species display alternating high and low Mg-bands within their shell walls that cannot be explained by temperature alone. Recent experiments demonstrate that intrashell Mg variability in Orbulina universa, which forms a spherical terminal shell, is paced by the diurnal light/dark cycle. Whether Mg-heterogeneity is also diurnally paced in species with more complex shell morphologies is unknown. Here we show that high Mg/Ca-calcite forms at night in cultured specimens of the multi-chambered species Neogloboquadrina dutertrei. Our results demonstrate that N. dutertrei adds a significant amount of calcite, and nearly all Mg-bands, after the final chamber forms. These results have implications for interpreting patterns of calcification in N. dutertrei and suggest that diurnal Mg-banding is an intrinsic component of biomineralization in planktic foraminifera.

  19. Distribution of foraminifera in Chincoteague Bay and the marshes of Assateague Island and the adjacent vicinity, Maryland and Virginia

    Science.gov (United States)

    Ellis, Alisha M.; Shaw, Jaimie; Osterman, Lisa E.; Smith, Christopher G.

    2017-11-28

    Scientists from the U.S. Geological Survey (USGS), St. Petersburg Coastal and Marine Science Center conducted a seasonal collection of estuarine, marsh, and sandy washover surface sediments from Chincoteague Bay, Tom’s Cove, and the surrounding Assateague Island and Delmarva Peninsula in March–April and October 2014, after Hurricane Sandy. Micropaleontology samples were collected as part of a complementary USGS Coastal and Marine Geology Program Sea-level and Storm Impacts on Estuarine Environments and Shorelines project study. For comparison with estuarine and overwash deposited foraminifera, a group of scientists from the USGS Woods Hole Coastal and Marine Science Center in Massachusetts collected samples offshore of Assateague Island on the inner continental shelf during a seafloor mapping study in the summer of 2014 and shipped select samples to the St. Petersburg Coastal and Marine Science Center. The micropaleontological subsamples analyzed for foraminifera at each site can be used to establish a foraminiferal baseline assemblage that takes into consideration the seasonal variability of the various species, regarding density and geographic extent, which are influenced by transient and stable environmental parameters. By understanding what parameters affect the various foraminiferal assemblages, researchers can delineate how alterations in salinity, temperature, or marsh-to-bay interactions, such as marsh erosion, might affect that assemblage.

  20. The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.

    Directory of Open Access Journals (Sweden)

    Tamar L Goulet

    Full Text Available 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

  1. 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

    2017-07-01

    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 geographic 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 coexisting 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 coexistence, and the effects of hosting a diverse suite of symbiont strains on colony ecology. © 2017 John Wiley & Sons Ltd.

  2. Asaia symbionts interfere with infection by Flavescence dorée phytoplasma in leafhoppers

    KAUST Repository

    Gonella, Elena

    2018-03-20

    The transmission of microbial pathogens by insect vectors can be affected by the insect’s microbial symbionts, which may compete in colonizing organs, express antagonistic factors or activate host immune response. Acetic acid bacteria of the genus Asaia are symbionts of the leafhopper Scaphoideus titanus, which transmits Flavescence dorée phytoplasma. These bacteria could be used as control agents against the disease. Here, we experimentally investigated the interaction between different strains of Asaia and phytoplasma transmission in the laboratory by using the model leafhopper Euscelidius variegatus and the plant host Vicia faba. We found that uncultivable and low concentrations of Asaia phylotypes were associated with E. variegatus. When we supplied different Asaia strains isolated from other insects and exhibiting different phenotypes to E. variegatus orally, the bacteria stably colonized the leafhopper, reached relatively higher densities and could then be isolated from the host. We conducted transmission trials of Flavescence dorée phytoplasma with individuals colonized with three exogenous Asaia strains. When the phytoplasma became established in the bodies of E. variegatus, leafhoppers were able to transmit it to broad beans, with transmission rates ranging from 33 to 76% in different experiments. However, leafhoppers that were colonized by one of the Asaia strains producing an air–liquid interface biofilm exhibited significantly reduced phytoplasma acquisition, with infection rates at 5–28%, whereas they were 25–77% in control insects. Although the mechanisms regulating this interference remain to be elucidated, our results provide evidence of the potential use of Asaia as a biocontrol agent.

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

    Directory of Open Access Journals (Sweden)

    Steven A Frese

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

  4. Fitness Impact of Obligate Intranuclear Bacterial Symbionts Depends on Host Growth Phase.

    Science.gov (United States)

    Bella, Chiara; Koehler, Lars; Grosser, Katrin; Berendonk, Thomas U; Petroni, Giulio; Schrallhammer, Martina

    2016-01-01

    According to text book definition, parasites reduce the fitness of their hosts whereas mutualists provide benefits. But biotic and abiotic factors influence symbiotic interactions, thus under certain circumstances parasites can provide benefits and mutualists can harm their host. Here we addressed the question which intrinsic biotic factors shape a symbiosis and are crucial for the outcome of the interaction between the obligate intranuclear bacterium Holospora caryophila ( Alphaproteobacteria; Rickettsiales ) and its unicellular eukaryotic host Paramecium biaurelia (Alveolata; Ciliophora). The virulence of H. caryophila , i.e., the negative fitness effect on host division and cell number, was determined by growth assays of several P. biaurelia strains. The performances of genetically identical lines either infected with H. caryophila or symbiont-free were compared. Following factors were considered as potentially influencing the outcome of the interaction: (1) host strain, (2) parasite strain, and (3) growth phases of the host. All three factors revealed a strong effect on the symbiosis. In presence of H. caryophila , the Paramecium density in the stationary growth phase decreased. Conversely, a positive effect of the bacteria during the exponential phase was observed for several host × parasite combinations resulting in an increased growth rate of infected P. biaurelia . Furthermore, the fitness impact of the tested endosymbionts on different P. biaurelia lines was not only dependent on one of the two involved strains but distinct for the specific combination. Depending on the current host growth phase, the presence of H. caryophila can be harmful or advantageous for P. biaurelia . Thus, under the tested experimental conditions, the symbionts can switch from the provision of benefits to the exploitation of host resources within the same host population and a time-span of less than 6 days.

  5. 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. © 2016 Phycological Society of America.

  6. Stringent Expression Control of Pathogenic R-body Production in Legume Symbiont Azorhizobium caulinodans

    Directory of Open Access Journals (Sweden)

    Jun-ichi Matsuoka

    2017-07-01

    Full Text Available 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 Caedibacter. Azorhizobium 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.

  7. Bacterial gut symbionts contribute to seed digestion in an omnivorous beetle.

    Directory of Open Access Journals (Sweden)

    Jonathan G Lundgren

    2010-05-01

    Full Text Available 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.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.We conclude that the relationships between the bacterium E. faecalis and this factultative granivore's ability to

  8. 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

  9. Bacterial Gut Symbionts Contribute to Seed Digestion in an Omnivorous Beetle

    Science.gov (United States)

    Lundgren, Jonathan G.; Lehman, R. Michael

    2010-01-01

    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 between the

  10. The presence of a mycangium in European Sinodendron cylindricum (Coleoptera: Lucanidae) and the associated yeast symbionts.

    Science.gov (United States)

    Tanahashi, Masahiko; Hawes, Colin J

    2016-01-01

    Part of the exoskeleton of some wood-inhabiting insects is modified to form a mycangium, which is a specialized organ used to convey fungal spores or yeasts to their offspring. Although most stag beetles (Coleoptera: Lucanidae) are known to have female-specific mycangia and associated yeast symbionts, the evolutionary origin of the mycangium in this group remains unresolved. Here, we report the presence of a mycangium and associated yeast symbionts in the European horned stag beetle Sinodendron cylindricum (L.), which belongs to an ancestral clade of the Lucanidae. The mycangium of S. cylindricum is shown to be female-specific and have the same developmental origin as that of other stag beetles. A total of five yeast strains were isolated from adult mycangia and larval gut of S. cylindricum Of these, we suggest that SICYAM1 is an undescribed yeast with taxonomic novelty, and have identified SICYLG3 as the xylose-fermenting yeast Scheffersomyces insectosa using nuclear ribosomal RNA and ITS sequences. The remaining three yeast strains, SICYAM2, SICYLG1, and SICYLG2, were assigned to the genus Sugiyamaella Yeast density in the adult mycangium was lower than that of the more evolutionarily advanced stag beetles, the European Lucanus cervus (L.) and Dorcus parallelipipedus (L.), which were also examined in this study. No living yeasts were isolated from the adult guts. However, a third instar larva of S. cylindricum harbored 10(4)-10(6) living yeasts in each gut region, which suggests that gut yeasts play an important role in these wood-feeding larvae. © The Authors 2016. Published by Oxford University Press on behalf of Entomological Society of America.

  11. DESIGN HANDBOOK ON GAS BEARINGS FOR GYROSCOPES.

    Science.gov (United States)

    consisting of a plain journal for supporting radial loads flanked by two spiral-grooved thrust bearings to support double-acting thrust loads; (3) the spiral-grooved journal bearing ; and (4) the spiral-grooved conical bearing.

  12. Hybrid Hydrostatic/Transient Roller Bearing Assembly

    Science.gov (United States)

    Justak, John F.

    1992-01-01

    Proposed bearing assembly for shaft of high-speed turbopump includes both hydrostatic and rolling-element bearings. Rolling-element bearing unloaded at high speed by centrifugal expansion of outer race and transient retainer.

  13. Two pad axially grooved hydrostatic bearing

    Science.gov (United States)

    San Andres, Luis A. (Inventor)

    1995-01-01

    A hydrostatic bearing having two axial grooves on opposite sides of the bearing for breaking the rotational symmetry in the dynamic force coefficients thus reducing the whirl frequency ratio and increasing the damping and stiffness of the hydrostatic bearing.

  14. Deformation Analysis of Fixed Bearing Inclined Plane Thrust Bearing

    Directory of Open Access Journals (Sweden)

    LI Yong--hai

    2017-02-01

    Full Text Available According to the theory of lubrication,Numerical simulation of the deformation of the thrust bearing of the fixed inclined plane was carried out,by finite element numerical analysis method and using the ANSYS software. The mathematical model of the oil film shape control equations about of the deformation and bearing is established. Analytical result showed that the force caused the tile surface generating concave deformation,and convex deformation increased with the height and the size of the load and bearing;Tile surface temperature generated convex deformation and increased with the height and the size of the temperature of bearing bush;The actual deformation of the tile surface is the superposition of the force and the thermal deformation. This conclusion can provide reference for the design and the application of thrust bearing,to reduce the tile surface,which is not conducive to the carrying capacity of the concave deformation.

  15. EFFECT OF BEARING MACROGEOMETRY ON BEARING PERFORMANCE IN ELASTOHYDRODYNAMIC LUBRICATION

    Directory of Open Access Journals (Sweden)

    Emin GÜLLÜ

    2000-01-01

    Full Text Available During manufacturing, ideal dimension and mutual positioning of machine elements proposed in project desing can be achieved only within certain range of tolerances. These tolerances, being classified in two groups, related to micro and macro geometry of machine elements, don't have to effect the functioning of these elements. So, as for all machine elements, investigation of the effects of macro and micro tolerances for journal bearings is important. In this study, we have investigated the effect of macro geometric irregularities of journal bearings on performance characteristics. In this regard, we have studied the change of bearing performance in respect to deviation from ideal circle for an elliptic shaft with small ovality rolling in circular journal bearing.

  16. Bears, Big and Little. Young Discovery Library Series.

    Science.gov (United States)

    Pfeffer, Pierre

    This book is written for children 5 through 10. Part of a series designed to develop their curiosity, fascinate them and educate them, this volume describes: (1) the eight species of bears, including black bear, brown bear, grizzly bear, spectacled bear, sun bear, sloth bear, polar bear, and giant panda; (2) geographical habitats of bears; (3)…

  17. Non-contacting "snubber bearing" for passive magnetic bearing systems

    Science.gov (United States)

    Post, Richard F

    2017-08-22

    A new non-contacting magnetic "snubber" bearing is provided for application to rotating systems such as vehicular electromechanical battery systems subject to frequent accelerations. The design is such that in the equilibrium position the drag force of the snubber is very small (milliwatts). However in a typical case, if the rotor is displaced by as little as 2 millimeters a large restoring force is generated without any physical contact between the stationary and rotating parts of the snubber bearing.

  18. Oscillatory growth in Larger Benthic Foraminifera: problems, interpretations and possible solutions.

    Science.gov (United States)

    Briguglio, Antonino; Eder, Wolfgang; Woeger, Julia; Kinoshita, Shunichi; Ferrandez-Canadell, Carles; Hohenegger, Johann

    2015-04-01

    The possibility to investigate cell growth and its oscillations through time in Larger Benthic Foraminifera (LBF) by means of Micro Computed Tomography (microCT) is a recent and well known methodology. However, the search for factors of oscillations around undisturbed growth - the latter can be modelled by theoretical growth functions (e.g. Gompertz and generalized logistic growth function) - is hampered by a number of factors which have been recently discovered and not yet published. Cycles are obtained based on a mean chamber building rate gained from specimens cultured in the laboratory because punctual data available in the literature are too incomplete to gain a more realistic growth model. The mean chamber building rate can be also modeled (e.g. Power-, Michaelis-Menten- and Bertallanffy function). The periodicity of the cycles observed in LBF is mostly concentrated around a prominent 29 to 30 days cycle. Other cycles, proportions and multiples of this dominant cycle are common, but probably should be considered as calculation effects in case of their inconsistency. The 30 days cycles are present in almost all specimens investigated, which may be a hint to a correlation between cell growth and the light intensity variation of lunar cycles, which can affect the photosynthetic activity of the endosymbionts in LBF tests. However, this correlation is challenged by a number of issues, which need to be further investigated. One of these problems is represented by the recent discovery of similar cycles in LBF tests, which have been laboratory-cultured and should therefore not show any environmental effects. A focused analysis of growth cycles observed in these laboratory tests showed that even if the periods are constant and significant at 30 days, their phases show a much broader variance compared to naturally grown specimens. Epigenetic signals and their influence on the oscillatory growth of cultivated organisms can be considered to play a major role in the

  19. Glacial-interglacial changes in the surface water characteristics of the Andaman Sea: Evidence from stable isotopic ratios of planktonic foraminifera

    Digital Repository Service at National Institute of Oceanography (India)

    Ahmad, S.M.; Patil, D.J.; Rao, P.S.; Nath, B.N.; Rao, B.R.; Rajagopalan, G.

    Stable carbon and oxygen isotopic analyses of the planktonic foraminifera (Globigerinoides ruber) from a deep sea sediment core (GC-1) in the Andaman Sea show high glacial-to-Holocene d18O amplitude of 2.1% which is consistent...

  20. Thin Dense Chrome Bearing Insertion Program

    National Research Council Canada - National Science Library

    Rhoads, Mark

    1997-01-01

    .... TDC coated bearings demonstrated improved corrosion and contamination resistance. TDC coated bearings also demonstrated acceptable performance during thermal cycle, oil-off, and induced defect conditions...