WorldWideScience

Sample records for symbiotic bacteroidales bacteria

  1. Effects of symbiotic bacteria on chemical sensitivity of Daphnia magna.

    Science.gov (United States)

    Manakul, Patcharaporn; Peerakietkhajorn, Saranya; Matsuura, Tomoaki; Kato, Yasuhiko; Watanabe, Hajime

    2017-07-01

    The crustacean zooplankton Daphnia magna has been widely used for chemical toxicity tests. Although abiotic factors have been well documented in ecotoxicological test protocols, biotic factors that may affect the sensitivity to chemical compounds remain limited. Recently, we identified symbiotic bacteria that are critical for the growth and reproduction of D. magna. The presence of symbiotic bacteria on Daphnia raised the question as to whether these bacteria have a positive or negative effect on toxicity tests. In order to evaluate the effects of symbiotic bacteria on toxicity tests, bacteria-free Daphnia were prepared, and their chemical sensitivities were compared with that of Daphnia with symbiotic bacteria based on an acute immobilization test. The Daphnia with symbiotic bacteria showed higher chemical resistance to nonylphenol, fenoxycarb, and pentachlorophenol than bacteria-free Daphnia. These results suggested potential roles of symbiotic bacteria in the chemical resistance of its host Daphnia. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Fighting malaria with engineered symbiotic bacteria from vector mosquitoes

    Science.gov (United States)

    Wang, Sibao; Ghosh, Anil K.; Bongio, Nicholas; Stebbings, Kevin A.; Lampe, David J.; Jacobs-Lorena, Marcelo

    2012-01-01

    The most vulnerable stages of Plasmodium development occur in the lumen of the mosquito midgut, a compartment shared with symbiotic bacteria. Here, we describe a strategy that uses symbiotic bacteria to deliver antimalaria effector molecules to the midgut lumen, thus rendering host mosquitoes refractory to malaria infection. The Escherichia coli hemolysin A secretion system was used to promote the secretion of a variety of anti-Plasmodium effector proteins by Pantoea agglomerans, a common mosquito symbiotic bacterium. These engineered P. agglomerans strains inhibited development of the human malaria parasite Plasmodium falciparum and rodent malaria parasite Plasmodium berghei by up to 98%. Significantly, the proportion of mosquitoes carrying parasites (prevalence) decreased by up to 84% for two of the effector molecules, scorpine, a potent antiplasmodial peptide and (EPIP)4, four copies of Plasmodium enolase–plasminogen interaction peptide that prevents plasminogen binding to the ookinete surface. We demonstrate the use of an engineered symbiotic bacterium to interfere with the development of P. falciparum in the mosquito. These findings provide the foundation for the use of genetically modified symbiotic bacteria as a powerful tool to combat malaria. PMID:22802646

  3. Recurrent evolution of gut symbiotic bacteria in pentatomid stinkbugs.

    Science.gov (United States)

    Hosokawa, Takahiro; Matsuura, Yu; Kikuchi, Yoshitomo; Fukatsu, Takema

    2016-01-01

    Diverse animals are intimately associated with microbial symbionts. How such host-symbiont associations have evolved is a fundamental biological issue. Recent studies have revealed a variety of evolutionary relationships, such as obligatory, facultative, and free-living, of gut bacterial symbiosis within the stinkbug family Pentatomidae, although the whole evolutionary picture remains elusive. Here we investigated a comprehensive assembly of Japanese pentatomid stinkbugs representing 28 genera, 35 species, and 143 populations. Polymerase chain reaction (PCR), cloning, and sequencing of bacterial 16S rRNA gene from their midgut symbiotic organ consistently detected a single bacterial species from each of the insect samples, indicating a general tendency toward monosymbiotic gut association. Bacterial sequences detected from different populations of the same species were completely or nearly identical, indicating that the majority of the gut symbiotic associations are stably maintained at the species level. Furthermore, bacterial sequences detected from different species in the same genus tended to form well-supported clades, suggesting that host-symbiont associations are often stable even at the genus level. Meanwhile, when we compared such sequences with published sequences available in DNA databases, we found a number of counter-examples to such stable host-symbiont relationships; i.e., symbionts from different host species in the same genus may be phylogenetically distant, and symbionts from the same host species may be phylogenetically diverse. Likewise, symbionts of diverse pentatomid species may be closely related to symbionts of other stinkbug families, and symbionts of diverse pentatomid species may even be allied to free-living bacteria. Molecular evolutionary analyses revealed that higher molecular evolutionary rates, higher AT nucleotide compositions, and smaller genome sizes tended to be associated with the pentatomid symbionts constituting the stable

  4. Leguminous plants: inventors of root nodules to accommodate symbiotic bacteria.

    Science.gov (United States)

    Suzaki, Takuya; Yoro, Emiko; Kawaguchi, Masayoshi

    2015-01-01

    Legumes and a few other plant species can establish a symbiotic relationship with nitrogen-fixing rhizobia, which enables them to survive in a nitrogen-deficient environment. During the course of nodulation, infection with rhizobia induces the dedifferentiation of host cells to form primordia of a symbiotic organ, the nodule, which prepares plants to accommodate rhizobia in host cells. While these nodulation processes are known to be genetically controlled by both plants and rhizobia, recent advances in studies on two model legumes, Lotus japonicus and Medicago truncatula, have provided great insight into the underlying plant-side molecular mechanism. In this chapter, we review such knowledge, with particular emphasis on two key processes of nodulation, nodule development and rhizobial invasion. Copyright © 2015 Elsevier Inc. All rights reserved.

  5. Identification of symbiotic nitrogen-fixing bacteria from three African leguminous trees in Gorongosa National Park.

    Science.gov (United States)

    Teixeira, Helena; Rodríguez-Echeverría, Susana

    2016-07-01

    The symbiosis between leguminous plants and symbiotic nitrogen-fixing bacteria is a key component of terrestrial ecosystems. Woody legumes are well represented in tropical African forests but despite their ecological and socio-economic importance, they have been little studied for this symbiosis. In this study, we examined the identity and diversity of symbiotic-nitrogen fixing bacteria associated with Acacia xanthophloea, Faidherbia albida and Albizia versicolor in the Gorongosa National Park (GNP) in Mozambique. To the best of our knowledge, this is the first report on the identity of symbiotic-nitrogen fixing bacteria in this region. 166 isolates were obtained and subjected to molecular identification. BOX-A1R PCR was used to discriminate different bacterial isolates and PCR-sequencing of 16S rDNA, and two housekeeping genes, glnII and recA, was used to identify the obtained bacteria. The gene nifH was also analyzed to assess the symbiotic capacity of the obtained bacteria. All isolates from F. albida and Al. versicolor belonged to the Bradyrhizobium genus whereas isolates from Ac. xanthophloea clustered with Mesorhizobium, Rhizobium or Ensifer strains. Soil chemical analysis revealed significant differences between the soils occupied by the three studied species. Thus, we found a clear delimitation in the rhizobial communities and soils associated with Ac. xanthophloea, F. albida and Al. versicolor, and higher rhizobial diversity for Ac. xanthophloea than previously reported. Copyright © 2016 Elsevier GmbH. All rights reserved.

  6. Symbiotic Bacteria Enable Olive Fly Larvae to Overcome Host Defenses

    International Nuclear Information System (INIS)

    Ben-Yosef, Michael; Yuval, Boaz; Pasternak, Zohar; Jurkevitch, Edouard

    2016-01-01

    Ripe fruit offer readily available nutrients for many animals, including fruit fly larvae (Diptera: Tephritidae) and their associated rot-inducing bacteria. Yet, during most of their ontogeny, fruit remain chemically defended and effectively suppress herbivores and pathogens by high levels of secondary metabolites. Olive flies (Bactrocera oleae) are uniquely able to develop in unripe olives. Unlike other frugivorous tephritids, the larvae maintain bacteria confined within their midgut caeca. We examined the interaction between larvae, their associated bacteria, and fruit chemical defence, hypothesizing that bacterial contribution to larval development is contingent on the phenology of fruit defensive chemistry. We demonstrate that larvae require their natural complement of bacteria (Candidatus Erwinia dacicola: Enterobacteriaceae) in order to develop in unripe olives. Conversely, when feeding on ripe fruit, larval development proceeds independently of these bacteria. Our experiments suggest that bacteria counteract the inhibitory effect of oleuropein—the principal phenolic glycoside in unripe olives. In light of these results, we suggest that the unique symbiosis in olive flies, compared with other frugivorous tephritids, is understood by considering the relationship between the fly, bacteria and fruit chemistry. When applied in an evolutionary context, this approach may also point out the forces which shaped symbioses across the Tephritidae. (author)

  7. An Overview on Marine Sponge-Symbiotic Bacteria as Unexhausted Sources for Natural Product Discovery

    Directory of Open Access Journals (Sweden)

    Candice M. Brinkmann

    2017-09-01

    Full Text Available Microbial symbiotic communities of marine macro-organisms carry functional metabolic profiles different to the ones found terrestrially and within surrounding marine environments. These symbiotic bacteria have increasingly been a focus of microbiologists working in marine environments due to a wide array of reported bioactive compounds of therapeutic importance resulting in various patent registrations. Revelations of symbiont-directed host specific functions and the true nature of host-symbiont interactions, combined with metagenomic advances detecting functional gene clusters, will inevitably open new avenues for identification and discovery of novel bioactive compounds of biotechnological value from marine resources. This review article provides an overview on bioactive marine symbiotic organisms with specific emphasis placed on the sponge-associated ones and invites the international scientific community to contribute towards establishment of in-depth information of the environmental parameters defining selection and acquisition of true symbionts by the host organisms.

  8. Bioactive potential of symbiotic bacteria and fungi from marine ...

    African Journals Online (AJOL)

    Marine sponges are rich in microbial biota. In this study, totally four sponges namely Callyspongia diffusa, Hyattella Cribriformis, Sigmadocia carnosa, Spongia officininalis Var ceylonensis were collected and their associated bacteria and fungi were isolated. Among the microbes isolated, Pseudomonas fluorescens and ...

  9. Exopolysaccharides produced by the symbiotic nitrogen-fixing bacteria of leguminosae

    OpenAIRE

    Bomfeti,Cleide Aparecida; Florentino,Ligiane Aparecida; Guimarães,Ana Paula; Cardoso,Patrícia Gomes; Guerreiro,Mário César; Moreira,Fatima Maria de Souza

    2011-01-01

    The process of biological nitrogen fixation (BNF), performed by symbiotic nitrogen fixing bacteria with legume species, commonly known as α and β rhizobia, provides high sustainability for the ecosystems. Its management as a biotechnology is well succeeded for improving crop yields. A remarkable example of this success is the inoculation of Brazilian soybeans with Bradyrhizobium strains. Rhizobia produce a wide diversity of chemical structures of exopolysaccharides (EPS). Although t...

  10. Olfactory attraction of Drosophila suzukii by symbiotic acetic acid bacteria

    KAUST Repository

    Mazzetto, Fabio

    2016-03-24

    Some species of acetic acid bacteria (AAB) play relevant roles in the metabolism and physiology of Drosophila spp. and in some cases convey benefits to their hosts. The pest Drosophila suzukii harbors a set of AAB similar to those of other Drosophila species. Here, we investigate the potential to exploit the ability of AAB to produce volatile substances that attract female D. suzukii. Using a two-way olfactometer bioassay, we investigate the preference of D. suzukii for strains of AAB, and using solid-phase microextraction gas chromatography–mass spectrometry we specifically characterize their volatile profiles to identify attractive and non-attractive components produced by strains from the genera Acetobacter, Gluconobacter, and Komagataeibacter. Flies had a preference for one strain of Komagataeibacter and two strains of Gluconobacter. Analyses of the volatile profiles from the preferred Gluconobacter isolates found that acetic acid is distinctively emitted even after 2 days of bacterial growth, confirming the relevance of this volatile in the profile of this isolate for attracting flies. Analyses of the volatile profile from the preferred Komagataeibacter isolate showed that a different volatile in its profile could be responsible for attracting D. suzukii. Moreover, variation in the concentration of butyric acid derivatives found in some strains may influence the preference of D. suzukii. Our results indicate that Gluconobacter and Komagataeibacter strains isolated from D. suzukii have the potential to provide substances that could be exploited to develop sustainable mass-trapping-based control approaches. © 2016 Springer-Verlag Berlin Heidelberg

  11. [Analysis of Symbiotic Genes of Leguminous Plants Nodule Bacteria Grown in the Southern Urals].

    Science.gov (United States)

    Baymiev, An Kh; Ivanova, E S; Gumenko, R S; Chubukova, O V; Baymiev, Al Kh

    2015-12-01

    Bacterial strains isolated from the nodules, tissues, and root surface of wild legumes growing in the Southern Urals related to the tribes Galegeae, Hedysareae, Genisteae, Trifolieae, and Loteae were examined for the presence in their genomes of symbiotic (sym) genes. It was found that the sym-genes are present in microorganisms isolated only from the nodules of the analyzed plants (sym+ -strains). Phylogenetic analysis of sym+ -strains on the basis of a comparative analysis of 16S rRNA gene sequences showed that sym+ -strains belong to five families of nodule bacteria: Mesorhizobium, Bradyrhizobium, Sinorhizobium, Rhizobium, and Phyllobacterium. A study the phylogeny of the sym-genes showed that the nodule bacteria of leguminous plants of the Southern Urals at the genus level are mainly characterized by a parallel evolution of symbiotic genes and the 16S rRNA gene. Thus, cases of horizontal transfer of sym genes, which sometimes leads to the formation of certain types of atypical rhizobial strains ofleguminous plants, are detected in nodule bacteria populations.

  12. Symbiotic Properties of Sinorhizobium Fredii, J-TGS50 an Indonesian Soybean Nodule Forming Bacteria

    International Nuclear Information System (INIS)

    Setiyo Hadi Waluyo

    2004-01-01

    Green House experiments were conducted to study symbiotic properties of Sinorhizobium Fredii, J-TGS50. Sinorhizobium Fredii USDA 192, USDA 201, USDA 205, USDA 206, USDA 217 and Bradyrhizobium japonicum USDA 110 were used as references. Yeast extract mannitol broth culture of the bacteria were made and used as inoculation for several local and imported soybean varieties used in this study. Plants were harvested at 20 days after inoculation. Number of nodules were counted, fresh weight of nodules and shoot were determined. S. Fredii J-TGS50 and S. Fredii USDA 192, USDA 201, USDA 205, USDA 206, USDA 217 were found different in their symbiotic properties. S. Fredii J-TGS50 formed nodules on same imported soybean. While there were no nodules obtained from the plant inoculated with S. Fredii USDA 192, USDA 201, USDA 205, USDA 206, USDA 217. S. Fredii J-TGS50 and recommended B. Japonicum USDA 110 formed nodule on several local soybean varieties. There was no differences between those two bacteria either in nodulation efficiency or in the effectiveness of the formed nodules. Results of this study can be concluded that S. Fredii, J-TGS50 is a native to Indonesian soil and it is a promising soybean nodule forming bacteria in Indonesia. Using indigenous bacteria is valuable. Since they are mostly more tolerant and adaptable than the introduced ones. An important aspect for the success of Biological Nitrogen Fixation (BNF) is insight in the structure of indigenous soybean rhizobia populations. Study on the biodiversity of soybean rhizobia was important conducted. (author)

  13. Proteomic insights into intra- and intercellular plant-bacteria symbiotic association during root nodule formation

    Directory of Open Access Journals (Sweden)

    Afshin eSalavati

    2013-02-01

    Full Text Available Over the last several decades, there have been a large number of studies done on the all aspects of legumes and bacteria which participate in nitrogen-fixing symbiosis. The analysis of legume-bacteria interaction is not just a matter of numerical complexity in terms of variants of gene products that can arise from a single gene. Bacteria regulate their quorum-sensing genes to enhance their ability to induce conjugation of plasmids and symbiotic islands, and various protein secretion mechanisms; that can stimulate a collection of chain reactions including species-specific combinations of plant-secretion isoflavonoids, complicated calcium signaling pathways and autoregulation of nodulation mechanisms. Quorum-sensing systems are introduced by the intra- and intercellular organization of gene products lead to protein–protein interactions or targeting of proteins to specific cellular structures. In this study, an attempt has been made to review significant contributions related to nodule formation and development and their impacts on cell proteome for better understanding of plant-bacterium interaction mechanism at protein level. This review would not only provide new insights into the plant-bacteria symbiosis response mechanisms but would also highlights the importance of studying changes in protein abundance inside and outside of cells in response to symbiosis. Furthermore, the application to agriculture programe of plant-bacteria interaction will be discussed.

  14. Cowpea symbiotic efficiency, pH and aluminum tolerance in nitrogen-fixing bacteria

    Directory of Open Access Journals (Sweden)

    Bruno Lima Soares

    2014-06-01

    Full Text Available Cowpea (Vigna unguiculata cultivation in northern and northeastern Brazil provides an excellent source of nutrients and carbohydrates for the poor and underprivileged. Production surplus leads to its consumption in other regions of Brazil and also as an export commodity. Its capacity to establish relationships with atmospheric nitrogen-fixing bacteria is crucial to the reduction of production costs and the environmental impact of nitrogen fertilizers. This study assessed the symbiotic efficiency of new strains of symbiotic nitrogen-fixing bacteria with cowpea and their tolerance to pH and aluminum. Twenty-seven strains of bacteria from different soils were evaluated under axenic conditions. These strains were compared to the following inoculant strains: INPA03-11B, UFLA03-84 and BR3267 and two controls that were not inoculated (with and without mineral nitrogen. Six strains and the three strains approved as inoculants were selected to increase the dry weight production of the aerial part (DWAP and were tested in pots with soil that had a high-density of nitrogen-fixing native rhizobia. In this experiment, three strains (UFLA03-164, UFLA03-153, and UFLA03-154 yielded higher DWAP values. These strains grow at pH levels of 5.0, 6.0, 6.8 and at high aluminum concentration levels, reaching 10(9 CFU mL-1. In particular UFLA03-84, UFLA03-153, and UFLA03-164 tolerate up to 20 mmol c dm-3 of Al+3. Inoculation with rhizobial strains, that had been carefully selected according to their ability to nodulate and fix N2, combined with their ability to compete in soils that are acidic and contain high levels of Al, is a cheaper and more sustainable alternative that can be made available to farmers than mineral fertilizers.

  15. A common genomic framework for a diverse assembly of plasmids in the symbiotic nitrogen fixing bacteria.

    Directory of Open Access Journals (Sweden)

    Lisa C Crossman

    2008-07-01

    Full Text Available This work centres on the genomic comparisons of two closely-related nitrogen-fixing symbiotic bacteria, Rhizobium leguminosarum biovar viciae 3841 and Rhizobium etli CFN42. These strains maintain a stable genomic core that is also common to other rhizobia species plus a very variable and significant accessory component. The chromosomes are highly syntenic, whereas plasmids are related by fewer syntenic blocks and have mosaic structures. The pairs of plasmids p42f-pRL12, p42e-pRL11 and p42b-pRL9 as well large parts of p42c with pRL10 are shown to be similar, whereas the symbiotic plasmids (p42d and pRL10 are structurally unrelated and seem to follow distinct evolutionary paths. Even though purifying selection is acting on the whole genome, the accessory component is evolving more rapidly. This component is constituted largely for proteins for transport of diverse metabolites and elements of external origin. The present analysis allows us to conclude that a heterogeneous and quickly diversifying group of plasmids co-exists in a common genomic framework.

  16. Nitrogen fixed by wheat plants as affected by nitrogen fertilizer levels and Non-symbiotic bacteria

    International Nuclear Information System (INIS)

    Soliman, S.; Aly, S.S.M.; Gadalla, A.M.; Abou Seeda, M.

    1995-01-01

    Inorganic nitrogen is required for all egyptian soils for wheat. Free living and N 2-fixing microorganisms are able associate closely related with the roots of geraminacae. Pot experiment studies were carried out to examine the response of wheat plants to inoculation with Azospirillum Brasilense and Azotobacter Chroococcum, single or in combination, under various levels of ammonium sulfate interaction between both the inoculants increased straw or grain yield as well as N-uptake by wheat plants with increasing N levels. Results showed that grains of wheat plants derived over 19,24 and 15% of its N content from the atmospheric - N 2 (Ndfa) with application of 25,50 and 75 mg N kg-1 soil in the presence of + Azospirillum + azotobacter. The final amount of N 2-fixers. The highest values of N 2-fixed were observed with mixed inoculants followed by inoculation with Azospirillum and then azotobacter. The recovery of applied ammonium sulfate-N was markedly increased by inoculation with combined inoculants, but less in uninoculated treatments. Seeds inoculated with non-symbiotic fixing bacteria could be saved about 25 kg N without much affecting the grain yield. i fig., 4 tabs

  17. Exploring functional contexts of symbiotic sustain within lichen-associated bacteria by comparative omics

    Science.gov (United States)

    Grube, Martin; Cernava, Tomislav; Soh, Jung; Fuchs, Stephan; Aschenbrenner, Ines; Lassek, Christian; Wegner, Uwe; Becher, Dörte; Riedel, Katharina; Sensen, Christoph W; Berg, Gabriele

    2015-01-01

    Symbioses represent a frequent and successful lifestyle on earth and lichens are one of their classic examples. Recently, bacterial communities were identified as stable, specific and structurally integrated partners of the lichen symbiosis, but their role has remained largely elusive in comparison to the well-known functions of the fungal and algal partners. We have explored the metabolic potentials of the microbiome using the lung lichen Lobaria pulmonaria as the model. Metagenomic and proteomic data were comparatively assessed and visualized by Voronoi treemaps. The study was complemented with molecular, microscopic and physiological assays. We have found that more than 800 bacterial species have the ability to contribute multiple aspects to the symbiotic system, including essential functions such as (i) nutrient supply, especially nitrogen, phosphorous and sulfur, (ii) resistance against biotic stress factors (that is, pathogen defense), (iii) resistance against abiotic factors, (iv) support of photosynthesis by provision of vitamin B12, (v) fungal and algal growth support by provision of hormones, (vi) detoxification of metabolites, and (vii) degradation of older parts of the lichen thallus. Our findings showed the potential of lichen-associated bacteria to interact with the fungal as well as algal partner to support health, growth and fitness of their hosts. We developed a model of the symbiosis depicting the functional multi-player network of the participants, and argue that the strategy of functional diversification in lichens supports the longevity and persistence of lichens under extreme and changing ecological conditions. PMID:25072413

  18. Mutagenic effect of UV-irradiation on Alfalfa nodule bacteria and studies on symbiotic properties of the auxotrophic mutants obtained

    International Nuclear Information System (INIS)

    Fedorov, S.N.; Butvina, O.Yu.; Simarov, B.V.

    1983-01-01

    Inactivation and mutagenous effect of UV-radiation on nodula bacteria of lucerne is studied. The effect of photoreactivation is found and optimum conditions for mutagenesis are determined. A method for fast determination of effectiveness and nitrogenous activity of Rhizobium melilati mutants is determined. Using this method symbiotic properties of obtained auxotrophic mutants are determined. The dependence between the alteration of nitrogen registering activity of mutants and their aquisition of definite types of auxotrophity, is determined

  19. Exopolysaccharides produced by the symbiotic nitrogen-fixing bacteria of leguminosae

    Directory of Open Access Journals (Sweden)

    Cleide Aparecida Bomfeti

    2011-06-01

    Full Text Available The process of biological nitrogen fixation (BNF, performed by symbiotic nitrogen fixing bacteria with legume species, commonly known as α and β rhizobia, provides high sustainability for the ecosystems. Its management as a biotechnology is well succeeded for improving crop yields. A remarkable example of this success is the inoculation of Brazilian soybeans with Bradyrhizobium strains. Rhizobia produce a wide diversity of chemical structures of exopolysaccharides (EPS. Although the role of EPS is relatively well studied in the process of BNF, their economic and environmental potential is not yet explored. These EPS are mostly species-specific heteropolysaccharides, which can vary according to the composition of sugars, their linkages in a single subunit, the repeating unit size and the degree of polymerization. Studies have showed that the EPS produced by rhizobia play an important role in the invasion process, infection threads formation, bacteroid and nodule development and plant defense response. These EPS also confer protection to these bacteria when exposed to environmental stresses. In general, strains of rhizobia that produce greater amounts of EPS are more tolerant to adverse conditions when compared with strains that produce less. Moreover, it is known that the EPS produced by microorganisms are widely used in various industrial activities. These compounds, also called biopolymers, provide a valid alternative for the commonly used in food industry through the development of products with identical properties or with better rheological characteristics, which can be used for new applications. The microbial EPS are also able to increase the adhesion of soil particles favoring the mechanical stability of aggregates, increasing levels of water retention and air flows in this environment. Due to the importance of EPS, in this review we discuss the role of these compounds in the process of BNF, in the adaptation of rhizobia to environmental

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

    Science.gov (United States)

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

    2008-12-01

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

  1. 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

  2. Differential utility of the Bacteroidales DNA and RNA markers in the tiered approach for microbial source tracking in subtropical seawater.

    Science.gov (United States)

    Liu, Rulong; Cheng, Ken H F; Wong, Klaine; Cheng, Samuel C S; Lau, Stanley C K

    2015-07-01

    Source tracking of fecal pollution is an emerging component in water quality monitoring. It may be implemented in a tiered approach involving Escherichia coli and/or Enterococcus spp. as the standard fecal indicator bacteria (FIB) and the 16S rRNA gene markers of Bacteroidales as source identifiers. The relative population dynamics of the source identifiers and the FIB may strongly influence the implementation of such approach. Currently, the relative performance of DNA and RNA as detection targets of Bacteroidales markers in the tiered approach is not known. We compared the decay of the DNA and RNA of the total (AllBac) and ruminant specific (CF128) Bacteroidales markers with those of the FIB in seawater spiked with cattle feces. Four treatments of light and oxygen availability simulating the subtropical seawater of Hong Kong were tested. All Bacteroidales markers decayed significantly slower than the FIB in all treatments. Nonetheless, the concentrations of the DNA and RNA markers and E. coli correlated significantly in normoxic seawater independent of light availability, and in hypoxic seawater only under light. In hypoxic seawater without light, the concentrations of RNA but not DNA markers correlated with that of E. coli. Generally, the correlations between Enterococcus spp. and Bacteroidales were insignificant. These results suggest that either DNA or RNA markers may complement E. coli in the tiered approach for normoxic or hypoxic seawater under light. When light is absent, either DNA or RNA markers may serve for normoxic seawater, but only the RNA markers are suitable for hypoxic seawater.

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

    Science.gov (United States)

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

  4. Metagenomic analysis reveals symbiotic relationship among bacteria in Microcystis-dominated community

    Directory of Open Access Journals (Sweden)

    Meili eXie

    2016-02-01

    Full Text Available Microcystis bloom, a cyanobacterial mass occurrence often found in eutrophicated water bodies, is one of the most serious threats to freshwater ecosystems worldwide. In nature, Microcystis forms aggregates or colonies that contain heterotrophic bacteria. The Microcystis-bacteria colonies were persistent even when they were maintained in lab culture for a long period. The relationship between Microcystis and the associated bacteria was investigated by a metagenomic approach in this study. We developed a visualization-guided method of binning for genome assembly after total colony DNA sequencing. We found that the method was effective in grouping sequences and it did not require reference genome sequence. Individual genomes of the colony bacteria were obtained and they provided valuable insights into microbial community structures. Analysis of metabolic pathways based on these genomes revealed that while all heterotrophic bacteria were dependent upon Microcystis for carbon and energy, Vitamin B12 biosynthesis, which is required for growth by Microcystis, was accomplished in a cooperative fashion among the bacteria. Our analysis also suggests that individual bacteria in the colony community contributed a complete pathway for degradation of benzoate, which is inhibitory to the cyanobacterial growth, and its ecological implication for Microcystis bloom is discussed.

  5. Molecular phylogeny of the genus Dactylopius (Hemiptera: Dactylopiidae) and identification of the symbiotic bacteria.

    Science.gov (United States)

    Ramírez-Puebla, S T; Rosenblueth, M; Chávez-Moreno, C K; de Lyra, M C Catanho Pereira; Tecante, A; Martínez-Romero, E

    2010-08-01

    Phylogenetic analyses, from polymerase chain reaction (PCR)-amplified 12S rRNA and 18S rRNA gene sequences from cochineal insects of the genus Dactylopius present in Mexico, showed that D. ceylonicus, D. confusus, and D. opuntiae are closely related. D. coccus constitutes a separate clade, and D. tomentosus is the most distantly related. Bacterial 16S rRNA sequences from all the Dactylopius species sampled showed a common β-proteobacteria, related to Azoarcus, also found in eggs and in bacteriocytes in D. coccus. We propose the name "Candidatus Dactylopiibacterium carminicum" for this endosymbiont. Other bacterial sequences recovered from the samples were close to those from soil or plant associated bacteria, like Massilia, Herbaspirillum, Acinetobacter, Mesorhizobium, and Sphingomonas, suggesting a possible horizontal transmission from Cactaceae plant sap to Dactylopius spp. during feeding. This is the first molecular analysis of Dactylopius species and of their associated bacteria.

  6. Yeast Creates a Niche for Symbiotic Lactic Acid Bacteria through Nitrogen Overflow.

    Science.gov (United States)

    Ponomarova, Olga; Gabrielli, Natalia; Sévin, Daniel C; Mülleder, Michael; Zirngibl, Katharina; Bulyha, Katsiaryna; Andrejev, Sergej; Kafkia, Eleni; Typas, Athanasios; Sauer, Uwe; Ralser, Markus; Patil, Kiran Raosaheb

    2017-10-25

    Many microorganisms live in communities and depend on metabolites secreted by fellow community members for survival. Yet our knowledge of interspecies metabolic dependencies is limited to few communities with small number of exchanged metabolites, and even less is known about cellular regulation facilitating metabolic exchange. Here we show how yeast enables growth of lactic acid bacteria through endogenous, multi-component, cross-feeding in a readily established community. In nitrogen-rich environments, Saccharomyces cerevisiae adjusts its metabolism by secreting a pool of metabolites, especially amino acids, and thereby enables survival of Lactobacillus plantarum and Lactococcus lactis. Quantity of the available nitrogen sources and the status of nitrogen catabolite repression pathways jointly modulate this niche creation. We demonstrate how nitrogen overflow by yeast benefits L. plantarum in grape juice, and contributes to emergence of mutualism with L. lactis in a medium with lactose. Our results illustrate how metabolic decisions of an individual species can benefit others. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  7. Characterization of diazotrophic bacteria non-symbiotic associated with eucalyptus (eucalyptus sp.) in Codazzi, Cesar (Colombia)

    International Nuclear Information System (INIS)

    Obando Castellanos, Dolly Melissa; Burgos Zabala, Ludy Beatriz; Rivera Botia, Diego Mauricio; Rubiano Garrido, Maria Fernanda; Divan Baldini, Vera Lucia; Bonilla Buitrago, Ruth Rebeca

    2010-01-01

    The effect of climatic seasons (rainy and dry) and the stratum sample (rhizospheric soil, roots and leaves) the population of the genera Azotobacter, Beijerinckia, Derxia, Azospirillum, Herbaspirillum, Gluconacetobacter and Burkholderia in soil rhizosphere, roots and leaves of eucalyptus (eucalyptus sp.). It also assesses their ability to produce indoles compounds as plant growth promoters and their acetylene reduction activity as an indicator of biological fixation of nitrogen. The results showed no statistically significant differences in the Duncan test (p ≤ 0.05) in the population with respect to the climate epoch, suggesting that these bacteria are able to tolerate stress conditions by different physiological mechanisms. With respect to the stratum sample isolates attempts of Herbaspirillum sp. and Azospirillum sp. significant differences in rhizospheric soil and roots. we obtained 44 isolates of which were grouped by phenotypic characterization as 14 suspected of Beijerinckia sp., 12 Azotobacter sp., 8 Derxia sp., 4 Herbaspirillum sp., 5 Azospirillum sp., 1 Gluconacetobacter sp. and 1 Burkholderia sp. due to their high potential were selected isolates C27, C26 and C25. These four strains present the best values of efficiency in vitro, exceeding production values of the reference strains used (A. chroococcum (AC1) and a. brasilense (SP7)).

  8. [Factor analysis of interactions between alfalfa nodule bacteria (Sinorhizobium meliloti) genes that regulate symbiotic nitrogen fixation].

    Science.gov (United States)

    Provorov, N A; Chuklina, E; Vorob'ev, N I; Onishchuk, O P; Simarov, B V

    2013-04-01

    Factor analysis has been conducted for the data on the interaction between the genes of the root nodule bacteria (rhizobia), which influence the efficiency of symbiosis with leguminous plants, including dctA (encoding succinate permease), dctBD (activating the dctA gene due to binding its enhancer in the presence of succinate), rpoN (activating the promoters of dctA and nitrogenase genes nifHDK), and nifA (activating the nitrogenase genes due to binding their enhancers). The analysis of the alfalfa rhizobia (Sinorhizobium meliloti) recombinants that contain additional copies ofthese genes suggested the antagonistic (epistatic) interaction between nifA and rpoN. It may be associated either with the competition for C compounds imported into the nodules between the energy production and nitrogen assimilation processes or with the competition for redox potentials between the oxidative phosphorylation and nitrogen fixation processes. Since the phenotypic effects of the studied genes depend on the activity of nitrogen export into the aerial parts of plants, we suppose that its accumulation in bacteroids impairs the activation of the nifHDK genes by the NifA protein due to its interaction with the GlnB protein (the nitrogen metabolism regulator) or with the FixLJ and ActSR proteins (the redox potential regulators).

  9. Metagenomic Survey of Potential Symbiotic Bacteria and Polyketide Synthase Genes in an Indonesian Marine Sponge

    Directory of Open Access Journals (Sweden)

    Nia M. Kurnia

    2017-01-01

    Full Text Available There has been emerging evidence that the bacteria associated with marine sponges are the key producers of many complex bioactive compounds. The as-yet uncultured candidate bacterial genus “Candidatus Entotheonella” of the marine sponge Theonella swinhoei from Japan have recently been recognized as the source of numerous pharmacologically relevant polyketides and modified peptides, as previously reported by the Piel group (Wilson et al. 2014. This work reported the presence of “Candidatus Entotheonella sp.” in the highly complex microbiome of an Indonesian marine sponge from Kapoposang Island, South Sulawesi. We further identified the Kapoposang sponge specimen used in this work as Rhabdastrella sp. based on the integrated morphological, histological, and cytochrome oxidase subunit I (COI gene analyses. To detect the polyketide biosynthetic machinery called type I polyketide synthase (PKS in this Indonesian Rhabdastrella sp., we amplified and cloned the ketosynthase-encoding DNA regions of approximately 700 bp from the uncultured sponge's microbiome. Further sequencing and analysis of several randomly chosen clones indicated that all of them are mostly likely involved in the biosynthesis of methyl-branched fatty acids. However, employing a PKS-targeting primer designed in this work led to the isolation of four positive clones. BlastX search and subsequent phylogenetic analysis showed that one of the positive clones, designed as RGK32, displayed high homology with ketosynthase domains of many type I PKS systems and may belong to the subclass cis-AT PKS group.

  10. Diversity and function of prevalent symbiotic marine bacteria in the genus Endozoicomonas

    KAUST Repository

    Neave, Matthew J.

    2016-08-24

    Endozoicomonas bacteria are emerging as extremely diverse and flexible symbionts of numerous marine hosts inhabiting oceans worldwide. Their hosts range from simple invertebrate species, such as sponges and corals, to complex vertebrates, such as fish. Although widely distributed, the functional role of Endozoicomonas within their host microenvironment is not well understood. In this review, we provide a summary of the currently recognized hosts of Endozoicomonas and their global distribution. Next, the potential functional roles of Endozoicomonas, particularly in light of recent microscopic, genomic, and genetic analyses, are discussed. These analyses suggest that Endozoicomonas typically reside in aggregates within host tissues, have a free-living stage due to their large genome sizes, show signs of host and local adaptation, participate in host-associated protein and carbohydrate transport and cycling, and harbour a high degree of genomic plasticity due to the large proportion of transposable elements residing in their genomes. This review will finish with a discussion on the methodological tools currently employed to study Endozoicomonas and host interactions and review future avenues for studying complex host-microbial symbioses.

  11. Effect of symbiotic bacteria added to the larval environment on the quality of the sterile male Mediterranean fruit fly, Ceratitis capitata

    International Nuclear Information System (INIS)

    Fekiri, Abdelwaheb; Arfaoui, Chaker

    2009-01-01

    The program of fight against Ceratite being based on the TIS becomes increasingly efficient when one controls these various factors well mainly the performances of the produced sterile males. While basing itself on the symbiotic relation between the bacteria present in the intestine of Ceratite and the latter, we have in this present adopted work at a method of breeding which could improve qualities of the male. This method consists in introducing certain beneficial bacteria in Ceratite (Pseudomonas, Citrobacter and Klebsiella) into the medium of breeding following various combinations. The effect of these bacteria was analyzed by carrying out various tests of quality control to release the parameters of quality (Productivity, Poids, Emergence and Aptitude for the flight) and the parameters of the sexual behavior (Latency time, Duration of coupling and competitiveness). (author)

  12. Effects of symbiotic bacteria and tree chemistry on the growth and reproduction of bark beetle fungal symbionts

    Science.gov (United States)

    A.S. Adams; C.R. Currie; Y. Cardoza; K.D. Klepzig; K.F. Raffa

    2009-01-01

    Bark beetles are associated with diverse assemblages of microorganisms, many of which affect their interactions with host plants and natural enemies. We tested how bacterial associates of three bark beetles with various types of host relationships affect growth and reproduction of their symbiotic fungi. Fungi were exposed to volatiles...

  13. Endophytic Bacteria Improve Plant Growth, Symbiotic Performance of Chickpea (Cicer arietinum L. and Induce Suppression of Root Rot Caused by Fusarium solani under Salt Stress

    Directory of Open Access Journals (Sweden)

    Dilfuza Egamberdieva

    2017-09-01

    Full Text Available Salinity causes disturbance in symbiotic performance of plants, and increases susceptibility of plants to soil-borne pathogens. Endophytic bacteria are an essential determinant of cross-tolerance to biotic and abiotic stresses in plants. The aim of this study was to isolate non–rhizobial endophytic bacteria from the root nodules of chickpea (Cicer arietinum L., and to assess their ability to improve plant growth and symbiotic performance, and to control root rot in chickpea under saline soil conditions. A total of 40 bacterial isolates from internal root tissues of chickpea grown in salinated soil were isolated. Four bacterial isolates, namely Bacillus cereus NUU1, Achromobacter xylosoxidans NUU2, Bacillus thuringiensis NUU3, and Bacillus subtilis NUU4 colonizing root tissue demonstrated plant beneficial traits and/or antagonistic activity against F. solani and thus were characterized in more detail. The strain B. subtilis NUU4 proved significant plant growth promotion capabilities, improved symbiotic performance of host plant with rhizobia, and promoted yield under saline soil as compared to untreated control plants under field conditions. A combined inoculation of chickpea with M. ciceri IC53 and B. subtilis NUU4 decreased H2O2 concentrations and increased proline contents compared to the un-inoculated plants indicating an alleviation of adverse effects of salt stress. Furthermore, the bacterial isolate was capable to reduce the infection rate of root rot in chickpea caused by F. solani. This is the first report of F. solani causing root rot of chickpea in a salinated soil of Uzbekistan. Our findings demonstrated that the endophytic B. subtilis strain NUU4 provides high potentials as a stimulator for plant growth and as biological control agent of chickpea root rot under saline soil conditions. These multiple relationships could provide promising practical approaches to increase the productivity of legumes under salt stress.

  14. In Vivo Isotopic Labeling of Symbiotic Bacteria Involved in Cellulose Degradation and Nitrogen Recycling within the Gut of the Forest Cockchafer (Melolontha hippocastani

    Directory of Open Access Journals (Sweden)

    Pol Alonso-Pernas

    2017-10-01

    Full Text Available The guts of insects harbor symbiotic bacterial communities. However, due to their complexity, it is challenging to relate a specific symbiotic phylotype to its corresponding function. In the present study, we focused on the forest cockchafer (Melolontha hippocastani, a phytophagous insect with a dual life cycle, consisting of a root-feeding larval stage and a leaf-feeding adult stage. By combining in vivo stable isotope probing (SIP with 13C cellulose and 15N urea as trophic links, with Illumina MiSeq (Illumina-SIP, we unraveled bacterial networks processing recalcitrant dietary components and recycling nitrogenous waste. The bacterial communities behind these processes change between larval and adult stages. In 13C cellulose-fed insects, the bacterial families Lachnospiraceae and Enterobacteriaceae were isotopically labeled in larvae and adults, respectively. In 15N urea-fed insects, the genera Burkholderia and Parabacteroides were isotopically labeled in larvae and adults, respectively. Additionally, the PICRUSt-predicted metagenome suggested a possible ability to degrade hemicellulose and to produce amino acids of, respectively, 13C cellulose- and 15N urea labeled bacteria. The incorporation of 15N from ingested urea back into the insect body was confirmed, in larvae and adults, by isotope ratio mass spectrometry (IRMS. Besides highlighting key bacterial symbionts of the gut of M. hippocastani, this study provides example on how Illumina-SIP with multiple trophic links can be used to target microorganisms embracing different roles within an environment.

  15. Vertical transmission and successive location of symbiotic bacteria during embryo development and larva formation in Corticium candelabrum (Porifera: Demospongiae)

    NARCIS (Netherlands)

    Caralt Bosch, de S.; Uriz, M.J.; Wijffels, R.H.

    2007-01-01

    This study reports on the transfer of heterotrophic bacteria from parental tissue to oocytes in the Mediterranean bacteriosponge Corticium candelabrum (Homosclerophorida) and the description of the successive locations of the microsymbionts during embryo development through transmission and scanning

  16. Stress tolerance, genetic analysis and symbiotic properties of root-nodulating bacteria isolated from Mediterranean leguminous shrubs in Central Spain.

    Science.gov (United States)

    Ruiz-Díez, Beatriz; Fajardo, Susana; Puertas-Mejía, Miguel Angel; de Felipe, María del Rosario; Fernández-Pascual, Mercedes

    2009-01-01

    Nine root-nodulating bacterial isolates were obtained from the leguminous shrubs Spartium junceum, Adenocarpus hispanicus, Cytisus purgans, Cytisus laburnuum, Retama sphaerocarpa and Colutea arborescens in areas of Central Spain. A poliphasic approach analyzing phenotypic, symbiotic and genetic properties was used to study their diversity and characterize them in relation to Mediterranean conditions. Stress tolerance assays revealed marked variations in salinity, extreme pH and cadmium tolerance compared with reference strains, with the majority showing salinity, alkalinity and Cd tolerance and three of them growing at acid pH. Variation within the 16S rRNA gene was examined by amplified 16S rDNA restriction analysis (ARDRA) and direct sequencing to show genetic diversity. Phylogeny confirmed the close relationship of four isolates with Bradyrhizobium canariense, three with Phylobacterium myrsinacearum, one with Rhizobium rhizogenes and another with Mesorhizobium huakuii. The cross inoculation tests revealed wide spectra of nodulation. This is the first report of P. myrsinacearum being able to nodulate these leguminous shrubs, and also the first time reported the association between B.canariense, R. rhizogenes and M. huakuii and C. laburnuum, C. purgans and C. arborescens, respectively. These results suggested that native rhizobia could be suitable candidates as biofertilizers and/or inoculants of leguminous shrubs with restoration or revegetation purposes in Mediterranean areas.

  17. Cool temperatures reduce antifungal activity of symbiotic bacteria of threatened amphibians--implications for disease management and patterns of decline.

    Directory of Open Access Journals (Sweden)

    Joshua H Daskin

    Full Text Available Chytridiomycosis, caused by the fungus Batrachochytrium dendrobatidis (Bd, is a widespread disease of amphibians responsible for population declines and extinctions. Some bacteria from amphibians' skins produce antimicrobial substances active against Bd. Supplementing populations of these cutaneous antifungal bacteria might help manage chytridiomycosis in wild amphibians. However, the activity of protective bacteria may depend upon environmental conditions. Biocontrol of Bd in nature thus requires knowledge of how environmental conditions affect their anti-Bd activity. For example, Bd-driven amphibian declines have often occurred at temperatures below Bd's optimum range. It is possible these declines occurred due to reduced anti-Bd activity of bacterial symbionts at cool temperatures. Better understanding of the effects of temperature on chytridiomycosis development could also improve risk evaluation for amphibian populations yet to encounter Bd. We characterized, at a range of temperatures approximating natural seasonal variation, the anti-Bd activity of bacterial symbionts from the skins of three species of rainforest tree frogs (Litoria nannotis, Litoria rheocola, and Litoria serrata. All three species declined during chytridiomycosis outbreaks in the late 1980s and early 1990s and have subsequently recovered to differing extents. We collected anti-Bd bacterial symbionts from frogs and cultured the bacteria at constant temperatures from 8 °C to 33 °C. Using a spectrophotometric assay, we monitored Bd growth in cell-free supernatants (CFSs from each temperature treatment. CFSs from 11 of 24 bacteria showed reduced anti-Bd activity in vitro when they were produced at cool temperatures similar to those encountered by the host species during population declines. Reduced anti-Bd activity of metabolites produced at low temperatures may, therefore, partially explain the association between Bd-driven declines and cool temperatures. We show that to

  18. Western Flower Thrips (Thysanoptera: Thripidae) preference for thrips-damaged leaves over fresh leaves enables uptake of symbiotic gut bacteria

    NARCIS (Netherlands)

    de Vries, E.J.; Vos, R.A.; Jacobs, G.; Breeuwer, J.A.J.

    2006-01-01

    To understand the evolution of insect gut symbionts it is important to determine how they are passed on to the next generation. We studied this process in Erwinia species bacteria that inhabit the gut of western flower thrips, Frankliniella occidentalis (Pergande) (Thysanoptera: Thripidae). This is

  19. Adjustment of host cells for accommodation of symbiotic bacteria: vacuole defunctionalization, HOPS suppression, and TIP1g retargeting in Medicago

    NARCIS (Netherlands)

    Gavrin, A.Y.; Kaiser, B.N.; Geiger, D.; Tyerman, S.D.; Wen, Z.; Bisseling, T.; Fedorova, E.E.

    2014-01-01

    In legume–rhizobia symbioses, the bacteria in infected cells are enclosed in a plant membrane, forming organelle-like compartments called symbiosomes. Symbiosomes remain as individual units and avoid fusion with lytic vacuoles of host cells. We observed changes in the vacuole volume of infected

  20. Effect of symbiotic bacteria added to the middle of the Mediterranean fruit fly larvae on the performance of sterile males

    International Nuclear Information System (INIS)

    Toukebri, Achraf; Kefi, Amal

    2009-01-01

    The program of the fight against the Mediterranean fly of fruits ''SIT'' becomes increasingly efficient when one control his various factors well mainly the performances of the sterile males within the unit. In this present work, we adopted a method of breeding which could improve quality of the sterile males intended for releasing. This method consists in introducing certain beneficial bacteria (Pseudomonas, Citrobacter and Klebsiella) into the milieu of breeding according to different combinations. The effect of these bacteria was analyzed by carrying out various tests of quality control to determin the parameters of quality (Productivity, weight, Emergence, flying aptitude) and the parameters of reproduction (latency time, Duration of coupling and competitiveness). According to the results obtained, we could observe changes on the level of the parameters of quality. The addition of Pseudomonas alone in the milieu of breeding significantly decreased the quality of the produced flies while the addition of this same bacteria in partnership with Citrobacter and Klebsiella showed a beneficial effect on their host. This is observed through the remarkable improvement of the competitiveness of the fly. Thus we can conclude that the presence of the bacteria alone or in synergy enormously affects the fitness flies and consequently their sexual competitiveness. (Author)

  1. Symbiotic bacteria (Erwinia sp.) in the gut of Frankliniella occidentalis (Thysanoptera: Thripidae) do not affect its ability to transmit tospovirus

    NARCIS (Netherlands)

    de Vries, E.J.; van de Wetering, F.; van der Hoek, M.M.; Jacobs, G.; Breeuwer, J.A.J.

    2012-01-01

    Tomato spotted wilt virus (TSWV) is one of the most harmful plant viruses and one of its most important vectors is the western flower thrips [Frankliniella occidentalis Pergande (Thysanoptera: Thripidae)]. Recently, we reported the close association of Erwinia sp. gut bacteria with this species of

  2. Antioxidant and Antibacterial Activity of the Beverage Obtained by Fermentation of Sweetened Lemon Balm (Melissa offi cinalis L. Tea with Symbiotic Consortium of Bacteria and Yeasts

    Directory of Open Access Journals (Sweden)

    Dragoljub D. Cvetković

    2014-01-01

    Full Text Available Kombucha is a fermented tea beverage which is traditionally prepared by fermenting sweetened black or green tea (Camellia sinensis L. with symbiotic consortium of bacteria and yeasts (SCOBY. In this study, lemon balm (Melissa offi cinalis L. was used as the only nitrogen source for kombucha fermentation. During the seven-day fermentation process, pH value, titratable acidity (TA, total phenolic content, phenolic compounds, and antioxidant activity against hydroxyl (˙OH and 1,1-diphenyl-2-picrylhydrazil (DPPH radicals were measured to detect the connection between the fermentation time and antioxidant and antibacterial activities of lemon balm kombucha. Antibacterial activity of fi nished beverages with optimum acidity (TA=4–4.5 g/L, the value which is confi rmed by long-time kombucha consumers, and enhanced acidity (TA=8.12 g/L was tested against eleven wild bacterial strains. The results showed that lemon balm could be successfully used as an alternative to C. sinensis L. for kombucha fermentation. Total phenolic content and antioxidant activity against DPPH radicals of lemon balm fermentation broth were higher than those of traditional kombucha. Rosmarinic acid is the main phenolic compound of the lemon balm-based kombucha that probably provides biological activity of the beverage. Judging from the EC50 values, kombucha beverages exhibited higher antioxidant activities compared with C. sinensis L. and M. offi cinalis L. infusions, which can probably be ascribed to SCOBY metabolites. Lemon balm kombucha with both optimum and enhanced acidity showed antibacterial activity, which can be primarily ascribed to acetic acid, but also to some other tea components and SCOBY metabolites.

  3. Performance evaluation of canine-associated Bacteroidales assays in a multi-laboratory comparison study

    Science.gov (United States)

    The contribution of fecal pollution from dogs in urbanized areas can be significant and is an often underestimated problem. Microbial source tracking methods (MST) utilizing quantitative PCR of dog-associated gene sequences encoding 16S rRNA of Bacteroidales are a useful tool to ...

  4. Screening for symbiotically effective and ecologically competitive ...

    African Journals Online (AJOL)

    This study was initiated to isolate and characterize chickpea rhizobia for their symbiotic effectiveness adapted to local environmental conditions. A total of seventy root nodule bacteria were isolated from different sampling sites in central and northern Ethiopia of which only 52% were rhizobia and the remaining were ...

  5. Give us the tools and we will do the job: symbiotic bacteria affect olive fly fitness in a diet-dependent fashion.

    Science.gov (United States)

    Ben-Yosef, Michael; Aharon, Yael; Jurkevitch, Edouard; Yuval, Boaz

    2010-05-22

    Olive flies (Bactrocera oleae) are intimately associated with bacteria throughout their life cycle, and both larvae and adults are morphologically adapted for housing bacteria in the digestive tract. We tested the hypothesis that these bacteria contribute to the adult fly's fitness in a diet-dependent fashion. We predicted that when dietary protein is superabundant, bacterial contribution will be minimal. Conversely, in the absence of protein, or when only non-essential amino acids are present (as in the fly's natural diet), we predicted that bacterial contribution to fitness will be significant. Accordingly, we manipulated diet and the presence of bacteria in female olive flies, and monitored fecundity--an indirect measure of fitness. Bacteria did not affect fecundity when females were fed a nutritionally poor diet of sucrose, or a protein-rich, nutritionally complete diet. However, when females were fed a diet containing non-essential amino acids as the sole source of amino nitrogen, egg production was significantly enhanced in the presence of bacteria. These results suggest that bacteria were able to compensate for the skewed amino acid composition of the diet and may be indispensable for wild adult olive flies that subsist mainly on nitrogen-poor resources such as honeydew.

  6. Give us the tools and we will do the job: symbiotic bacteria affect olive fly fitness in a diet-dependent fashion

    International Nuclear Information System (INIS)

    Ben-Yosef, M.; Yuval, B.; Aharon, Y.; Jurkevitch, E.

    2010-01-01

    Olive flies (Bactrocera oleae) are intimately associated with bacteria throughout their life cycle, and both larvae and adults are morphologically adapted for housing bacteria in the digestive tract. We tested the hypothesis that these bacteria contribute to the adult fly's fitness in a diet-dependent fashion. We predicted that when dietary protein is superabundant, bacterial contribution will be minimal. Conversely, in the absence of protein, or when only non-essential amino acids are present (as in the fly's natural diet), we predicted that bacterial contribution to fitness will be significant. Accordingly, we manipulated diet and the presence of bacteria in female olive flies, and monitored fecundity, an indirect measure of fitness. Bacteria did not affect fecundity when females were fed a nutritionally poor diet of sucrose, or a protein-rich, nutritionally complete diet. However, when females were fed a diet containing non-essential amino acids as the sole source of amino nitrogen, egg production was significantly enhanced in the presence of bacteria. These results suggest that bacteria were able to compensate for the skewed amino acid composition of the diet and may be indispensable for wild adult olive flies that subsist mainly on nitrogen-poor resources such as honeydew. (author)

  7. Effects of ascorbic acid and glucose oxidase levels on the viability of probiotic bacteria and the physical and sensory characteristics in symbiotic ice-cream

    Directory of Open Access Journals (Sweden)

    M. B. Akın

    2015-05-01

    Full Text Available In this study, the effects of addition of different amounts of ascorbic acid and glucose oxidase on the properties of symbiotic ice cream were investigated. Ice-cream containing inulin (2 % (w/w was produced by mixing fortified milk fermented with probiotic strains with the ice-cream mixes containing different ascorbic acid and glucose oxidase concentrations (0.025, 0.05, 0.1 (w/w. The cultures were grown (37 °C, 12 h in UHT skimmed milk. The fermented milk was added to the ice-cream mix up to a level of 10 % w/w. Increasing the concentration of ascorbic acid stimulated the growth of Lactobacillus acidophilus LA-5 (L. acidophilus and Bifidobacterium animalis subsp. lactis BB-12 (Bifidobacterium BB-12. On contrary, increasing the concentration of glucose oxidase negatively affected the growth of L. acidophilus and Bifidobacterium BB-12. However, both, ascorbic acid and glucose oxidase concentration had no effect on physical and sensory properties of ice cream. The results suggested that the addition of ascorbic acid stimulated the growth of L. acidophilus and Bifidobacterium BB-12 and could be recommended for ice cream production.

  8. Fixação do nitrogênio do ar pelas bactérias que vivem em simbiose com as raízes da centrosema Fixation of the atmospheric nitrogen by bacteria which live symbiotically on centrosema

    Directory of Open Access Journals (Sweden)

    J. Casado Montojos

    1963-01-01

    Full Text Available Continuando a série de trabalhos sôbre a quantidade de nitrogênio atmosférico fixada por bactérias que vivem em simbiose com raízes de leguminosas, são relatados os resultados encontrados em centrosema (Centrosema pubescens Benth. Foram utilizados vasos de Mitscherlich, com terra-roxa-misturada. A colheita das plantas foi efetuada por ocasião do florescimento. A parte aérea foi pesada para cálculo da quantidade de massa verde produzida, e, em seguida, juntamente com as raízes, sêca a 60°C até pêso constante. Determinaram-se os teores de nitrogênio na parte aérea e subterrânea das plantas, assim como da terra dos vasos. Os resultados mostraram elevada capacidade de fixação simbiótica de nitrogênio pela centrosema correspondente a cêrca de 204 quilogramas de nitrogênio por hectare.Following a series of research work with the purpose of verifying the amount of atmospheric nitrogen fixed by symbiotic bacteria, the authors report in this paper the results on their research with the leguminous plant Centrosema pubescens Benth. This experiment was conducted in Mitscherlich pots containing terra-roxa-misturada obtained from a 20 cm deep layer of soil taken from the Central Experiment Station "Theodureto de Camargo", in Campinas. The plants were cut in the blooming period, as this is the proper season for turning over green manure crops. The aerial portion of the plants was weighed so as to determine the total production of green matter and then it was dried together with the roots at 60°C. Thus, nitrogen of the total plant was determined and the same analysis was done at the end of the experiment for the soil removed from the pots. According to the results of this experiment, it was found that 204 kilograms of nitrogen per hectare were fixed, showing therefore that centrosema has a high capacity of symbiotic nitrogen fixation.

  9. Antioxidant and Antibacterial Activity of the Beverage Obtained by Fermentation of Sweetened Lemon Balm
(Melissa officinalisL.) Tea with Symbiotic Consortium 
of Bacteria and Yeasts.

    Science.gov (United States)

    Velićanski, Aleksandra S; Cvetković, Dragoljub D; Markov, Siniša L; Šaponjac, Vesna T Tumbas; Vulić, Jelena J

    2014-12-01

    Kombucha is a fermented tea beverage which is traditionally prepared by fermenting sweetened black or green tea ( Camellia sinensis L.) with symbiotic consortium of bacteria and yeasts (SCOBY). In this study, lemon balm ( Melissa officinalis L.) was used as the only nitrogen source for kombucha fermentation. During the seven-day fermentation process, pH value, titratable acidity (TA), total phenolic content, phenolic compounds, and antioxidant activity against hydroxyl ( ˙ OH) and 1,1-diphenyl-2-picrylhydrazil (DPPH) radicals were measured to detect the connection between the fermentation time and antioxidant and antibacterial activities of lemon balm kombucha. Antibacterial activity of finished beverages with optimum acidity (TA=4-4.5 g/L), the value which is confirmed by long-time kombucha consumers, and enhanced acidity (TA=8.12 g/L) was tested against eleven wild bacterial strains. The results showed that lemon balm could be successfully used as an alternative to C. sinensis L. for kombucha fermentation. Total phenolic content and antioxidant activity against DPPH radicals of lemon balm fermentation broth were higher than those of traditional kombucha. Rosmarinic acid is the main phenolic compound of the lemon balm-based kombucha that probably provides biological activity of the beverage. Judging from the EC 50 values, kombucha beverages exhibited higher antioxidant activities compared with C. sinensis L. and M. officinalis L. infusions, which can probably be ascribed to SCOBY metabolites. Lemon balm kombucha with both optimum and enhanced acidity showed antibacterial activity, which can be primarily ascribed to acetic acid, but also to some other tea components and SCOBY metabolites.

  10. Tolerância de bactérias diazotróficas simbióticas à salinidade in vitro Tolerance of diazotrophic symbiotic bacteria to salinity

    Directory of Open Access Journals (Sweden)

    Rafaela Simão Abrahão Nóbrega

    2004-08-01

    Full Text Available A busca de estirpes de bactérias diazotróficas simbióticas tolerantes à salinidade, em conjunto com a seleção de hospedeiros, tem por objetivo aumentar o desempenho da simbiose e manter a produtividade vegetal de forma sustentada em condições de estresse salino. Doze estirpes de bactérias diazotróficas de diferentes procedências foram estudadas quanto à tolerância a diferentes concentrações de NaCl em meios de cultura 79 e LB. As estirpes que apresentaram maior tolerância à salinidade (30 g L-1 em meio 79 foram: BR 6806 e BR 4007, ambas de crescimento rápido isoladas de solos do nordeste brasileiro, UFLA 03-51 e UFLA 03-65, de crescimento rápido e UFLA 03-84, de crescimento lento, sendo as três últimas oriundas da região Amazônica. Essas também estiveram entre as mais tolerantes em meio de cultura LB. A estirpe UFLA 03-84, selecionada em trabalhos prévios por sua alta eficiência para caupi (Vigna unguiculata, pode ser indicada para estudos de inoculação, visando a aumentar o rendimento dessa cultura em solos salinos. Os meios de cultura 79 e LB foram eficientes para avaliar a tolerância relativa de rizóbio a NaCl, mas o meio 79 é mais indicado, pois permite o crescimento de todas as estirpes. Pelos resultados, infere-se haver relação entre tolerância in vitro à salinidade e origem dos microssimbiontes, pois as estirpes BR 4007 e BR 6806, oriundas do Ceará, estiveram entre as mais tolerantes.Tolerance to salinity of diazotrophic bacteriaand their host species could increase plant growth and sustainability in salt stressed soils. Twelve diazotrophic bacteria strains were studied regarding their tolerance to different NaCl concentrations in 79 and LB media. More tolerant (30 g L-1 strains in 79 medium were: the fast growers BR 6806 and BR 4007, isolated from northeast Brazil, UFLA 03-51 and UFLA 03-65, and slow growing strain UFLA03-84, being these last three isolated from Amazon region. These strains were among

  11. Symbiotic relationship of Thiothrix spp. with an echinoderm

    Energy Technology Data Exchange (ETDEWEB)

    Brigmon, R.L. [Westinghouse Savannah River Co., Aiken, SC (United States); De Ridder, C. [Univ. Libre de Bruxelles, Brussels (Belgium). Lab. de Biologie Marine

    1998-09-01

    Thiothrix-like bacteria have been reported as symbionts in invertebrates from sulfide-rich habitats. Isolation of these symbiotic Thiothrix-like bacteria has failed, and the organisms have not been previously identified with certainty. The genus Thiothrix was created for ensheathed filamentous bacteria that oxidize sulfide and deposit sulfur granules internally, attach to substrates, produce gliding gonidia, and form rosettes. Immunoassay procedures were used to investigate the symbiotic relationship of Thiothrix spp. in the intestinal cecum of the spatangoid species Echinocardium cordatum. Thiothrix spp. were identified in nodule samples from E. cordatum digestive tubes based on microscopic examination, enzyme-linked immunosorbent assay, and indirect immunofluorescence. Thiothrix spp. protein made up as much as 84% of the total protein content of the nodules. This is the first identification of Thiothrix spp. internally symbiotic with marine invertebrates.

  12. Outbursts in Symbiotic Binaries

    Science.gov (United States)

    Sonneborn, George (Technical Monitor); Kenyon, Scott J.

    2004-01-01

    Two models have been proposed for the outbursts of symbiotic stars. In the thermonuclear model, outbursts begin when the hydrogen burning shell of a hot white dwarf reaches a critical mass. After a rapid increase in the luminosity and effective temperature, the white dwarf evolves at constant luminosity to lower effective temperatures, remains at optical maximum for several years, and then returns to quiescence along a white dwarf cooling curve. In disk instability models, the brightness rises when the accretion rate from the disk onto the central white dwarf abruptly increases by factors of 5-20. After a few month to several year period at maximum, both the luminosity and the effective temperature of the disk decline as the system returns to quiescence. If most symbiotic stars undergo thermonuclear eruptions, then symbiotics are probably poor candidates for type I supernovae. However, they can then provide approx. 10% of the material which stars recycle back into the interstellar medium. If disk instabilities are the dominant eruption mechanism, symbiotics are promising type Ia candidates but recycle less material into the interstellar medium.

  13. Detection and persistence of fecal Bacteroidales as water quality indicators in unchlorinated drinking water

    DEFF Research Database (Denmark)

    Saunders, Aaron Marc; Kristiansen, Anja; Lund, Marie Braad

    2009-01-01

    doi:10.1016/j.syapm.2008.11.004 The results of this study support the use of fecal Bacteroidales qPCR as a rapid method to complement traditional, culture dependent, water quality indicators in systems where drinking water is supplied without chlorination or other forms of disinfection. A SYBR...

  14. Outbursts of symbiotic novae

    International Nuclear Information System (INIS)

    Kenyon, S.J.; Truran, J.W.

    1983-01-01

    We discuss possible conditions under which thermonuclear burning episodes in the hydrogen-rich envelopes of accreting white dwarfs give rise to outbursts similar in nature to those observed in the symbiotic stars AG Peg, RT Ser, RR Tel, AS 239, V1016 Cyg, V1329 Cyg, and HM Sge. In principle, thermonuclear runaways involving low-luminosity white dwarfs accreting matter at low rates produce configurations that evolve into A--F supergiants at maximum visual light and which resemble the outbursts of RR Tel, RT Ser, and AG peg. Very weak, nondegenerage hydrogen shell flashes on white dwarfs accreting matter at high rates (M> or approx. =10 -8 M/sub sun/ yr -1 ) do not produce cool supergiants at maximum, and may explain the outbursts in V1016 Cyg, V1329 Cyg, and HM Sge. The low accretion rates demanded for systems developing strong hydrogen shell flashes on low-luminsoity white dwarfs are not compatible with observations of ''normal'' quiescent symbiotic stars. The extremely slow outbursts of symbiotic novae appear to be typical of accreting white dwarfs in wide binaries, which suggests that the outbursts of classical novae may be accelerated by the interaction of the expanding white dwarf envelope with its close binary companion

  15. Green symbiotic cloud communications

    CERN Document Server

    Mustafa, H D; Desai, Uday B; Baveja, Brij Mohan

    2017-01-01

    This book intends to change the perception of modern day telecommunications. Communication systems, usually perceived as “dumb pipes”, carrying information / data from one point to another, are evolved into intelligently communicating smart systems. The book introduces a new field of cloud communications. The concept, theory, and architecture of this new field of cloud communications are discussed. The book lays down nine design postulates that form the basis of the development of a first of its kind cloud communication paradigm entitled Green Symbiotic Cloud Communications or GSCC. The proposed design postulates are formulated in a generic way to form the backbone for development of systems and technologies of the future. The book can be used to develop courses that serve as an essential part of graduate curriculum in computer science and electrical engineering. Such courses can be independent or part of high-level research courses. The book will also be of interest to a wide range of readers including b...

  16. Nodulation outer proteins: double-edged swords of symbiotic rhizobia.

    Science.gov (United States)

    Staehelin, Christian; Krishnan, Hari B

    2015-09-15

    Rhizobia are nitrogen-fixing bacteria that establish a nodule symbiosis with legumes. Nodule formation depends on signals and surface determinants produced by both symbiotic partners. Among them, rhizobial Nops (nodulation outer proteins) play a crucial symbiotic role in many strain-host combinations. Nops are defined as proteins secreted via a rhizobial T3SS (type III secretion system). Functional T3SSs have been characterized in many rhizobial strains. Nops have been identified using various genetic, biochemical, proteomic, genomic and experimental approaches. Certain Nops represent extracellular components of the T3SS, which are visible in electron micrographs as bacterial surface appendages called T3 (type III) pili. Other Nops are T3 effector proteins that can be translocated into plant cells. Rhizobial T3 effectors manipulate cellular processes in host cells to suppress plant defence responses against rhizobia and to promote symbiosis-related processes. Accordingly, mutant strains deficient in synthesis or secretion of T3 effectors show reduced symbiotic properties on certain host plants. On the other hand, direct or indirect recognition of T3 effectors by plant cells expressing specific R (resistance) proteins can result in effector triggered defence responses that negatively affect rhizobial infection. Hence Nops are double-edged swords that may promote establishment of symbiosis with one legume (symbiotic factors) and impair symbiotic processes when bacteria are inoculated on another legume species (asymbiotic factors). In the present review, we provide an overview of our current understanding of Nops. We summarize their symbiotic effects, their biochemical properties and their possible modes of action. Finally, we discuss future perspectives in the field of T3 effector research. © 2015 Authors; published by Portland Press Limited.

  17. Bacteroidales Secreted Antimicrobial Proteins Target Surface Molecules Necessary for Gut Colonization and Mediate Competition In Vivo

    Directory of Open Access Journals (Sweden)

    Kevin G. Roelofs

    2016-08-01

    Full Text Available We recently showed that human gut Bacteroidales species secrete antimicrobial proteins (BSAPs, and we characterized in vitro the first such BSAP produced by Bacteroides fragilis. In this study, we identified a second potent BSAP produced by the ubiquitous and abundant human gut species Bacteroides uniformis. The two BSAPs contain a membrane attack complex/perforin (MACPF domain but share very little sequence similarity. We identified the target molecules of BSAP-sensitive cells and showed that each BSAP targets a different class of surface molecule: BSAP-1 targets an outer membrane protein of sensitive B. fragilis strains, and BSAP-2 targets the O-antigen glycan of lipopolysaccharide (LPS of sensitive B. uniformis strains. Species-wide genomic and phenotypic analyses of B. fragilis and B. uniformis showed that BSAP-producing strains circumvent killing by synthesizing an orthologous nontargeted surface molecule. The BSAP genes are adjacent to the gene(s encoding their target replacements, suggesting coacquisition. Using a gnotobiotic mouse competitive-colonization model, we found that the BSAP surface targets are important for colonization of the mammalian gut, thereby explaining why they are maintained in sensitive strains and why they were replaced rather than deleted in BSAP-producing strains. Using isogenic BSAP-producing, -sensitive, and -resistant strains, we show that a BSAP-producing strain outcompetes a sensitive strain but not a resistant strain in the mammalian gut. Human gut metagenomic datasets reveal that BSAP-1-sensitive strains do not cooccur with BSAP-1-producing strains in human gut microbiotas, further supporting the idea that BSAPs are important competitive factors with relevance to the strain-level composition of the human gut microbiota.

  18. Genetic and Molecular Mechanisms Underlying Symbiotic Specificity in Legume-Rhizobium Interactions

    Directory of Open Access Journals (Sweden)

    Qi Wang

    2018-03-01

    Full Text Available Legumes are able to form a symbiotic relationship with nitrogen-fixing soil bacteria called rhizobia. The result of this symbiosis is to form nodules on the plant root, within which the bacteria can convert atmospheric nitrogen into ammonia that can be used by the plant. Establishment of a successful symbiosis requires the two symbiotic partners to be compatible with each other throughout the process of symbiotic development. However, incompatibility frequently occurs, such that a bacterial strain is unable to nodulate a particular host plant or forms nodules that are incapable of fixing nitrogen. Genetic and molecular mechanisms that regulate symbiotic specificity are diverse, involving a wide range of host and bacterial genes/signals with various modes of action. In this review, we will provide an update on our current knowledge of how the recognition specificity has evolved in the context of symbiosis signaling and plant immunity.

  19. Assessment of a new Bacteroidales marker targeting North American beaver (Castor canadensis) fecal pollution by real-time PCR.

    Science.gov (United States)

    Marti, Romain; Zhang, Yun; Tien, Yuan-Ching; Lapen, David R; Topp, Edward

    2013-11-01

    In many settings wildlife can be a significant source of fecal pathogen input into surface water. The North American beaver (Castor canadensis) is a zoonotic reservoir for several human pathogens including Cryptosporidium spp. and Giardia spp. In order to specifically detect fecal pollution by beavers, we have developed and validated a beaver-specific Bacteroidales marker, designated Beapol01, based on the 16S rRNA gene. The marker is suitable for quantifying pollution using real-time PCR. The specificity and sensitivity of the marker was excellent, Beaver signal was detected in water of a mixed-activity watershed harbouring this rodent. Overall, Beapol01 will be useful for a better understanding of fecal source inputs in drainage basins inhabited by the beaver. © 2013.

  20. Microbiome change by symbiotic invasion in lichens

    Science.gov (United States)

    Maier, Stefanie; Wedin, Mats; Fernandez-Brime, Samantha; Cronholm, Bodil; Westberg, Martin; Weber, Bettina; Grube, Martin

    2016-04-01

    Biological soil crusts (BSC) seal the soil surface from erosive forces in many habitats where plants cannot compete. Lichens symbioses of fungi and algae often form significant fraction of these microbial assemblages. In addition to the fungal symbiont, many species of other fungi can inhabit the lichenic structures and interact with their hosts in different ways, ranging from commensalism to parasitism. More than 1800 species of lichenicolous (lichen-inhabiting) fungi are known to science. One example is Diploschistes muscorum, a common species in lichen-dominated BSC that infects lichens of the genus Cladonia. D. muscorum starts as a lichenicolous fungus, invading the lichen Cladonia symphycarpa and gradually develops an independent Diploschistes lichen thallus. Furthermore, bacterial groups, such as Alphaproteobacteria and Acidobacteria, have been consistently recovered from lichen thalli and evidence is rapidly accumulating that these microbes may generally play integral roles in the lichen symbiosis. Here we describe lichen microbiome dynamics as the parasitic lichen D. muscorum takes over C. symphycarpa. We used high-throughput 16S rRNA gene and photobiont-specific ITS rDNA sequencing to track bacterial and algal transitions during the infection process, and employed fluorescence in situ hybridization to localize bacteria in the Cladonia and Diploschistes lichen thalli. We sampled four transitional stages, at sites in Sweden and Germany: A) Cladonia with no visible infection, B) early infection stage defined by the first visible Diploschistes thallus, C) late-stage infection with parts of the Cladonia thallus still identifiable, and D) final stage with a fully developed Diploschistes thallus, A gradual microbiome shift occurred during the transition, but fractions of Cladonia-associated bacteria were retained during the process of symbiotic reorganization. Consistent changes observed across sites included a notable decrease in the relative abundance of

  1. Review on Association Between Corals and Their Symbiotic Microorganisms From the Ecology and Biotechnology Perspective

    Directory of Open Access Journals (Sweden)

    Zahra Amini Khoei

    2017-04-01

    Full Text Available Background: Corals have a diversity of prokaryotic communities as an internal or external symbiotic . This review will examine the association between corals and their symbiotic microorganisms from the ecology and biotechnology perspective. Material and Methods: In this study, articles were examined which indexed in Pubmed, Science Direct, Google Scholar and Scirus databases. Keywords we used included coral, symbiotic microorganisms, ecology, and biotechnology. Finally, overall of 120 articles and reports, 103 articles were evaluated by eliminating the same articles. Results: The Corals symbiotic microorganisms stay on in the ecological niches such as the surface mucus layer, tissue and their skeleton. They play role in the cycle of sulfur, nitrogen fixation, production of antimicrobial compounds and protect corals against pathogens. Many bioactive compounds which attributed to invertebrates such as sponges and corals in fact they are produced by symbiotic bacteria. Various metabolites produced by these microorganisms can be used as medicine. Five screening strategies including conventional screening, met genomics, genomics, combinatorial biosynthesis, and synthetic biology are used for marine microbial natural products discovery and development. Conclusion: According to the collected material we can be concluded that, the ecological studies about the natural association between corals and their symbiotic microorganisms were technological prerequisite for biomedical research and they make clear the road to attainment to bioactive compounds in fauna. Also, in the first step, it is recommended that modern technology and advanced screening methods used to identification of marine organisms and then to identify secondary metabolites among them.

  2. Nitrogen cycling in summer active perennial grass systems in South Australia: Non-symbiotic nitrogen fixation

    NARCIS (Netherlands)

    Gupta, V.V.S.R.; Kroker, S.J.; Hicks, M.; Davoren, W.; Descheemaeker, K.K.E.; Llewellyn, R.

    2014-01-01

    Non-symbiotic nitrogen (N2) fixation by diazotrophic bacteria is a potential source for biological N inputs in non-leguminous crops and pastures. Perennial grasses generally add larger quantities of above- and belowground plant residues to soil, and so can support higher levels of soil biological

  3. NPR1 Protein Regulates Pathogenic and Symbiotic Interactions between Rhizobium and Legumes and Non-Legumes

    OpenAIRE

    Peleg-Grossman, Smadar; Golani, Yael; Kaye, Yuval; Melamed-Book, Naomi; Levine, Alex

    2009-01-01

    BACKGROUND: Legumes are unique in their ability to establish symbiotic interaction with rhizobacteria from Rhizobium genus, which provide them with available nitrogen. Nodulation factors (NFs) produced by Rhizobium initiate legume root hair deformation and curling that entrap the bacteria, and allow it to grow inside the plant. In contrast, legumes and non-legumes activate defense responses when inoculated with pathogenic bacteria. One major defense pathway is mediated by salicylic acid (SA)....

  4. Host range, symbiotic effectiveness and nodulation competitiveness ...

    African Journals Online (AJOL)

    SERVER

    2008-04-17

    Apr 17, 2008 ... This symbiotic interaction is of agronomic and ecological importance because of its significant amount of nitrogen to the total nitrogen budget in terrestrial ecosystems (Postgate,. 1998). An important characteristic of this symbiotic interaction is host specificity, where defined species of rhizobia forms nodules ...

  5. Rhizobial exopolysaccharides: genetic control and symbiotic functions

    Directory of Open Access Journals (Sweden)

    Mazur Andrzej

    2006-02-01

    Full Text Available Abstract Specific complex interactions between soil bacteria belonging to Rhizobium, Sinorhizobium, Mesorhizobium, Phylorhizobium, Bradyrhizobium and Azorhizobium commonly known as rhizobia, and their host leguminous plants result in development of root nodules. Nodules are new organs that consist mainly of plant cells infected with bacteroids that provide the host plant with fixed nitrogen. Proper nodule development requires the synthesis and perception of signal molecules such as lipochitooligosaccharides, called Nod factors that are important for induction of nodule development. Bacterial surface polysaccharides are also crucial for establishment of successful symbiosis with legumes. Sugar polymers of rhizobia are composed of a number of different polysaccharides, such as lipopolysaccharides (LPS, capsular polysaccharides (CPS or K-antigens, neutral β-1, 2-glucans and acidic extracellular polysaccharides (EPS. Despite extensive research, the molecular function of the surface polysaccharides in symbiosis remains unclear. This review focuses on exopolysaccharides that are especially important for the invasion that leads to formation of indetermined (with persistent meristem type of nodules on legumes such as clover, vetch, peas or alfalfa. The significance of EPS synthesis in symbiotic interactions of Rhizobium leguminosarum with clover is especially noticed. Accumulating data suggest that exopolysaccharides may be involved in invasion and nodule development, bacterial release from infection threads, bacteroid development, suppression of plant defense response and protection against plant antimicrobial compounds. Rhizobial exopolysaccharides are species-specific heteropolysaccharide polymers composed of common sugars that are substituted with non-carbohydrate residues. Synthesis of repeating units of exopolysaccharide, their modification, polymerization and export to the cell surface is controlled by clusters of genes, named exo/exs, exp or

  6. Decay of Bacteroidales genetic markers in relation to traditional fecal indicators for water quality modeling of drinking water sources.

    Science.gov (United States)

    Sokolova, Ekaterina; Aström, Johan; Pettersson, Thomas J R; Bergstedt, Olof; Hermansson, Malte

    2012-01-17

    The implementation of microbial fecal source tracking (MST) methods in drinking water management is limited by the lack of knowledge on the transport and decay of host-specific genetic markers in water sources. To address these limitations, the decay and transport of human (BacH) and ruminant (BacR) fecal Bacteroidales 16S rRNA genetic markers in a drinking water source (Lake Rådasjön in Sweden) were simulated using a microbiological model coupled to a three-dimensional hydrodynamic model. The microbiological model was calibrated using data from outdoor microcosm trials performed in March, August, and November 2010 to determine the decay of BacH and BacR markers in relation to traditional fecal indicators. The microcosm trials indicated that the persistence of BacH and BacR in the microcosms was not significantly different from the persistence of traditional fecal indicators. The modeling of BacH and BacR transport within the lake illustrated that the highest levels of genetic markers at the raw water intakes were associated with human fecal sources (on-site sewers and emergency sewer overflow). This novel modeling approach improves the interpretation of MST data, especially when fecal pollution from the same host group is released into the water source from different sites in the catchment.

  7. What hydra has to say about the role and origin of symbiotic interactions.

    Science.gov (United States)

    Bosch, Thomas C G

    2012-08-01

    The Hydra holobiont involves at least three types of organisms that all share a long coevolutionary history and appear to depend on each other. Here I review how symbiotic algae and stably associated bacteria interact with the Hydra host and where in the tissue they are located. In particular I discuss the role of Toll-like receptor (TLR) signaling in maintaining Hydra's species-specific microbiota. I also discuss studies in Hydra viridis and its symbiotic Chlorella algae which indicate that the symbiotic algae are critically involved in the control of sexual differentiation in green Hydra. Finally, I review the state of "omics" in this tripartite association and the fact that the functioning of this holobiont is also a tale of several genomes.

  8. Influence of Temperature on Symbiotic Bacterium Composition in Successive Generations of Egg Parasitoid, Anagrus nilaparvatae

    Directory of Open Access Journals (Sweden)

    Wang Xin

    2016-07-01

    Full Text Available Anagrus nilaparvatae is the dominant egg parasitoid of rice planthoppers and plays an important role in biological control. Symbiotic bacteria can significantly influence the development, survival, reproduction and population differentiation of their hosts. To study the influence of temperature on symbiotic bacterial composition in the successive generations of A. nilaparvatae, A. nilaparvatae were raised under different constant temperatures of 22 °C, 25 °C, 28 °C, 31 °C and 34 °C. Polymerase chain reaction-denaturing gradient gel electrophoresis was used to investigate the diversity of symbiotic bacteria. Our results revealed that the endophytic bacteria of A. nilaparvatae were Pantoea sp., Pseudomonas sp. and some uncultured bacteria. The bacterial community composition in A. nilaparvatae significantly varied among different temperatures and generations, which might be partially caused by temperature, feeding behavior and the physical changes of hosts. However, the analysis of wsp gene showed that the Wolbachia in A. nilaparvatae belonged to group A, sub-group Mors and sub-group Dro. Sub-group Mors was absolutely dominant, and this Wolbachia composition remained stable in different temperatures and generations, except for the 3rd generation under 34 °C during which sub-group Dro became the dominant Wolbachia. The above results suggest that the continuous high temperature of 34 °C can influence the Wolbachia community composition in A. nilaparvatae.

  9. Comparative Genomics of Symbiotic Bacteria in Earthworm Nephridia

    DEFF Research Database (Denmark)

    Kjeldsen, Kasper Urup; Pinel, Nicolas; Lund, Marie Braad

    The excretory and osmoregulatory organs (nephridia) of lumbricid earthworms are densely colonized by extracellular bacterial symbionts belonging to the newly established betaproteobacterial genus Verminephrobacter. The nephridial symbiont of the earthworm Eisenia fetida was subjected to full genome...... sequencing along with two of its closest relatives; the plant pathogenic Acidovorax avena subsp. citrulli and the free-living Acidovorax sp. JS42. In addition, the genome of the nephridial symbiont of the earthworm Aporrectodea tuberculata was partially sequenced. In order to resolve the functional...

  10. Whole-Genome Sequences of Three Symbiotic Endozoicomonas Bacteria

    KAUST Repository

    Neave, Matthew J.

    2014-08-14

    Members of the genus Endozoicomonas associate with a wide range of marine organisms. Here, we report on the whole-genome sequencing, assembly, and annotation of three Endozoicomonas type strains. These data will assist in exploring interactions between Endozoicomonas organisms and their hosts, and it will aid in the assembly of genomes from uncultivated Endozoicomonas spp.

  11. The effect of soil carbon on symbiotic nitrogen fixation and symbiotic ...

    African Journals Online (AJOL)

    Soil organic carbon (SOC) is the main attribute of high-quality soil. The amount of nitrogen fixed by Rhizobium symbiotically with Trifolium repens (white clover) is ultimately determined by the quality of the soil environment. The effect of SOC on the total number of symbiotic and saprophytic rhizobia was determined.

  12. Symbiotic ß-proteobacteria beyond legumes: Burkholderia in Rubiaceae.

    Directory of Open Access Journals (Sweden)

    Brecht Verstraete

    Full Text Available Symbiotic ß-proteobacteria not only occur in root nodules of legumes but are also found in leaves of certain Rubiaceae. The discovery of bacteria in plants formerly not implicated in endosymbiosis suggests a wider occurrence of plant-microbe interactions. Several ß-proteobacteria of the genus Burkholderia are detected in close association with tropical plants. This interaction has occurred three times independently, which suggest a recent and open plant-bacteria association. The presence or absence of Burkholderia endophytes is consistent on genus level and therefore implies a predictive value for the discovery of bacteria. Only a single Burkholderia species is found in association with a given plant species. However, the endophyte species are promiscuous and can be found in association with several plant species. Most of the endophytes are part of the plant-associated beneficial and environmental group, but others are closely related to B. glathei. This soil bacteria, together with related nodulating and non-nodulating endophytes, is therefore transferred to a newly defined and larger PBE group within the genus Burkholderia.

  13. Non-symbiotic Bradyrhizobium ecotypes dominate North American forest soils.

    Science.gov (United States)

    VanInsberghe, David; Maas, Kendra R; Cardenas, Erick; Strachan, Cameron R; Hallam, Steven J; Mohn, William W

    2015-11-01

    The genus Bradyrhizobium has served as a model system for studying host-microbe symbiotic interactions and nitrogen fixation due to its importance in agricultural productivity and global nitrogen cycling. In this study, we identify a bacterial group affiliated with this genus that dominates the microbial communities of coniferous forest soils from six distinct ecozones across North America. Representative isolates from this group were obtained and characterized. Using quantitative population genomics, we show that forest soil populations of Bradyrhizobium represent ecotypes incapable of nodulating legume root hairs or fixing atmospheric nitrogen. Instead, these populations appear to be free living and have a greater potential for metabolizing aromatic carbon sources than their close symbiotic relatives. In addition, we identify fine-scaled differentiation between populations inhabiting neighboring soil layers that illustrate how diversity within Bradyrhizobium is structured by habitat similarity. These findings reconcile incongruent observations about this widely studied and important group of bacteria and highlight the value of ecological context to interpretations of microbial diversity and taxonomy. These results further suggest that the influence of this genus likely extends well beyond facilitating agriculture, especially as forest ecosystems are large and integral components of the biosphere. In addition, this study demonstrates how focusing research on economically important microorganisms can bias our understanding of the natural world.

  14. Application of leftover sample material from waterborne protozoa monitoring for the molecular detection of Bacteroidales and fecal source tracking markers

    Science.gov (United States)

    In this study, we examined the potential for detecting fecal bacteria and microbial source tracking markers in samples discarded during the concentration of Cryptosporidium and Giardia using USEPA Method 1623. Recovery rates for different fecal bacteria were determined using sp...

  15. Symbiotic Stars in X-rays

    Science.gov (United States)

    Luna, G. J. M.; Sokoloski, J. L.; Mukai, K.; Nelson, T.

    2014-01-01

    Until recently, symbiotic binary systems in which a white dwarf accretes from a red giant were thought to be mainly a soft X-ray population. Here we describe the detection with the X-ray Telescope (XRT) on the Swift satellite of 9 white dwarf symbiotics that were not previously known to be X-ray sources and one that was previously detected as a supersoft X-ray source. The 9 new X-ray detections were the result of a survey of 41 symbiotic stars, and they increase the number of symbiotic stars known to be X-ray sources by approximately 30%. Swift/XRT detected all of the new X-ray sources at energies greater than 2 keV. Their X-ray spectra are consistent with thermal emission and fall naturally into three distinct groups. The first group contains those sources with a single, highly absorbed hard component, which we identify as probably coming from an accretion-disk boundary layer. The second group is composed of those sources with a single, soft X-ray spectral component, which likely arises in a region where low-velocity shocks produce X-ray emission, i.e. a colliding-wind region. The third group consists of those sources with both hard and soft X-ray spectral components. We also find that unlike in the optical, where rapid, stochastic brightness variations from the accretion disk typically are not seen, detectable UV flickering is a common property of symbiotic stars. Supporting our physical interpretation of the two X-ray spectral components, simultaneous Swift UV photometry shows that symbiotic stars with harder X-ray emission tend to have stronger UV flickering, which is usually associated with accretion through a disk. To place these new observations in the context of previous work on X-ray emission from symbiotic stars, we modified and extended the alpha/beta/gamma classification scheme for symbiotic-star X-ray spectra that was introduced by Muerset et al. based upon observations with the ROSAT satellite, to include a new sigma classification for sources with

  16. Betaproteobacteria Limnohabitans strains increase fecundity in the crustacean Daphnia magna: symbiotic relationship between major bacterioplankton and zooplankton in freshwater ecosystem.

    Czech Academy of Sciences Publication Activity Database

    Peerakietkhajorn, S.; Kato, Y.; Kasalický, Vojtěch; Matsuura, T.; Watanabe, H.

    2016-01-01

    Roč. 18, č. 8 (2016), s. 2366-2374 ISSN 1462-2912 R&D Projects: GA ČR(CZ) GA13-00243S Institutional support: RVO:60077344 Keywords : Daphnia * symbiotic bacteria * Limnohabitans * fecundity Subject RIV: EE - Microbiology, Virology Impact factor: 5.395, year: 2016

  17. Distinct Bacterial Communities Associated with the Coral Model Aiptasia in Aposymbiotic and Symbiotic States with Symbiodinium

    OpenAIRE

    Röthig, Till; Costa, Rúben M.; Simona, Fabia; Baumgarten, Sebastian; Torres, Ana F.; Radhakrishnan, Anand; Aranda, Manuel; Voolstra, Christian R.

    2016-01-01

    Coral reefs are in decline. The basic functional unit of coral reefs is the coral metaorganism or holobiont consisting of the cnidarian host animal, symbiotic algae of the genus Symbiodinium, and a specific consortium of bacteria (among others), but research is slow due to the difficulty of working with corals. Aiptasia has proven a tractable model system to elucidate the intricacies of cnidarian-dinoflagellate symbioses, but characterization of the associated bacterial microbiome and the und...

  18. Symbiotic nitrogen-fixing bacterial populations trapped from soils under agroforestry systems in the Western Amazon

    Directory of Open Access Journals (Sweden)

    Paula Marcela Duque Jaramillo

    2013-12-01

    Full Text Available Cowpea (Vigna unguiculata is an important grain-producing legume that can forego nitrogen fertilization by establishing an efficient symbiosis with nitrogen-fixing bacteria. Although inoculating strains have already been selected for this species, little is known about the genotypic and symbiotic diversity of native rhizobia. Recently, Bradyrhizobium has been shown to be the genus most frequently trapped by cowpea in agricultural soils of the Amazon region. We investigated the genetic and symbiotic diversity of 148 bacterial strains with different phenotypic and cultural properties isolated from the nodules of the trap species cowpea, which was inoculated with samples from soils under agroforestry systems from the western Amazon. Sixty non-nodulating strains indicated a high frequency of endophytic strains in the nodules. The 88 authenticated strains had varying symbiotic efficiency. The SPAD (Soil Plant Analysis Development index (indirect measurement of chlorophyll content was more efficient at evaluating the contribution of symbiotic N2-fixation than shoot dry matter under axenic conditions. Cowpea-nodulating bacteria exhibited a high level of genetic diversity, with 68 genotypes identified by BOX-PCR. Sequencing of the 16S rRNA gene showed a predominance of the genus Bradyrhizobium, which accounted for 70 % of all strains sequenced. Other genera identified were Rhizobium, Ochrobactrum, Paenibacillus, Bosea, Bacillus, Enterobacter, and Stenotrophomonas. These results support the promiscuity of cowpea and demonstrate the high genetic and symbiotic diversity of rhizobia in soils under agroforestry systems, with some strains exhibiting potential for use as inoculants. The predominance of Bradyrhizobium in land uses with different plant communities and soil characteristics reflects the adaptation of this genus to the Amazon region.

  19. NPR1 protein regulates pathogenic and symbiotic interactions between Rhizobium and legumes and non-legumes.

    Science.gov (United States)

    Peleg-Grossman, Smadar; Golani, Yael; Kaye, Yuval; Melamed-Book, Naomi; Levine, Alex

    2009-12-21

    Legumes are unique in their ability to establish symbiotic interaction with rhizobacteria from Rhizobium genus, which provide them with available nitrogen. Nodulation factors (NFs) produced by Rhizobium initiate legume root hair deformation and curling that entrap the bacteria, and allow it to grow inside the plant. In contrast, legumes and non-legumes activate defense responses when inoculated with pathogenic bacteria. One major defense pathway is mediated by salicylic acid (SA). SA is sensed and transduced to downstream defense components by a redox-regulated protein called NPR1. We used Arabidopsis mutants in SA defense pathway to test the role of NPR1 in symbiotic interactions. Inoculation of Sinorhizobium meliloti or purified NF on Medicago truncatula or nim1/npr1 A. thaliana mutants induced root hair deformation and transcription of early and late nodulins. Application of S. meliloti or NF on M. truncatula or A. thaliana roots also induced a strong oxidative burst that lasted much longer than in plants inoculated with pathogenic or mutualistic bacteria. Transient overexpression of NPR1 in M. truncatula suppressed root hair curling, while inhibition of NPR1 expression by RNAi accelerated curling. We show that, while NPR1 has a positive effect on pathogen resistance, it has a negative effect on symbiotic interactions, by inhibiting root hair deformation and nodulin expression. Our results also show that basic plant responses to Rhizobium inoculation are conserved in legumes and non-legumes.

  20. NPR1 protein regulates pathogenic and symbiotic interactions between Rhizobium and legumes and non-legumes.

    Directory of Open Access Journals (Sweden)

    Smadar Peleg-Grossman

    Full Text Available BACKGROUND: Legumes are unique in their ability to establish symbiotic interaction with rhizobacteria from Rhizobium genus, which provide them with available nitrogen. Nodulation factors (NFs produced by Rhizobium initiate legume root hair deformation and curling that entrap the bacteria, and allow it to grow inside the plant. In contrast, legumes and non-legumes activate defense responses when inoculated with pathogenic bacteria. One major defense pathway is mediated by salicylic acid (SA. SA is sensed and transduced to downstream defense components by a redox-regulated protein called NPR1. METHODOLOGY/PRINCIPAL FINDINGS: We used Arabidopsis mutants in SA defense pathway to test the role of NPR1 in symbiotic interactions. Inoculation of Sinorhizobium meliloti or purified NF on Medicago truncatula or nim1/npr1 A. thaliana mutants induced root hair deformation and transcription of early and late nodulins. Application of S. meliloti or NF on M. truncatula or A. thaliana roots also induced a strong oxidative burst that lasted much longer than in plants inoculated with pathogenic or mutualistic bacteria. Transient overexpression of NPR1 in M. truncatula suppressed root hair curling, while inhibition of NPR1 expression by RNAi accelerated curling. CONCLUSIONS/SIGNIFICANCE: We show that, while NPR1 has a positive effect on pathogen resistance, it has a negative effect on symbiotic interactions, by inhibiting root hair deformation and nodulin expression. Our results also show that basic plant responses to Rhizobium inoculation are conserved in legumes and non-legumes.

  1. Symbiots: Conceptual Interventions Into Urban Energy Systems

    DEFF Research Database (Denmark)

    Bergström, Jenny; Mazé, Ramia; Redströmand, Johan

    2009-01-01

    Symbiots set out to examine values such as ease-of-use, comfort, and rationality assumed within conventions of ‘good design’, in order to expose issues related to energy consumption and current human- (versus eco-) centered design paradigms. Exploring re-interpretations of graphical patterns......, architectural configura- tions and electrical infrastructure typical in Swedish cities, Symbiots takes the form of a photo series in the genre of contemporary hy- per-real art photography. Painting a vivid pic- ture of alternatives to current local priorities around energy consumption, the three design concepts...

  2. Learning fair play in industrial symbiotic relations

    NARCIS (Netherlands)

    Yazan, Devrim Murat; Yazdanpanah, Vahid; Fraccascia, Luca; Mancuso, Erika; Fantin, Valentina

    2017-01-01

    In this paper, we provide practical decision support to managers in firms involved in Industrial Symbiotic Relations (ISRs) in terms of strategy development and test the hypothesis that in the long-term, playing a fair strategy for sharing obtainable ISR-related benefits is dominant. We employ

  3. A report of symbiotic Siphonostomatoida (Copepoda) infecting ...

    African Journals Online (AJOL)

    Collected copepod specimens were fixed and preserved in 70% ethanol and studied with the stereo- and light microscopes. Most of the examined hosts (38) were infected with symbiotic siphonostomatoids. Ten different species representing five families were identified. Of these, seven represent new host records while four ...

  4. Clade identification of symbiotic zooxanthellae of dominant ...

    African Journals Online (AJOL)

    Tidal pools have harsh conditions due to lack of nutrients, food and pronounced changes in physical conditions such as pH, salinity and temperature, hence the study of symbiotic zooxanthellae on coral reefs of tidal pool seems to be necessary. Samples of five coral species that include Siderastrea savignyana, ...

  5. Screening soybean genotypes for promiscuous symbiotic ...

    African Journals Online (AJOL)

    A greenhouse experiment was conducted at Makerere University Agricultural Research Institute, Kabanyolo (MUARIK) with the aim of screening of soybean germplasm for promiscuous symbiotic association with Bradyrhizobium sp. in order to identify genotypes with potential to be used as parents to initiate a breeding ...

  6. Onion thrips, Thrips tabaci, have gut bacteria that are closely related to the symbionts of the western flower thrips, Frankliniella occidentalis

    NARCIS (Netherlands)

    Vries, de E.J.; Wurff, van der A.W.G.; Jacobs, G.; Breeuwer, J.A.J.

    2008-01-01

    It has been shown that many insects have Enterobacteriaceae bacteria in their gut system. The western flower thrips, Frankliniella occidentalis Pergande [Thysanoptera: Thripidae], has a symbiotic relation with Erwinia species gut bacteria. To determine if other Thripidae species have similar

  7. Effects of aposymbiotic and symbiotic aphids on parasitoid progeny development and adult oviposition behavior within aphid instars.

    Science.gov (United States)

    Cheng, Rui-Xia; Meng, Ling; Li, Bao-Ping

    2010-04-01

    This study aims at exploring the potential relationship between aphidiine parasitoid development and the primary endosymbiont in aphids by focusing on specific aphid instars and the relative effects on parasitoid oviposition behavior and progeny development. Lysiphlebus ambiguus (Aphidiidae, Hymenoptera) is a solitary parasitoid of several species of aphids, including Aphis fabae. In this study, A. fabae was treated with antibiotic rifampicin to obtain aposymbiotic hosts and exposed to parasitism. L. ambiguus launched significantly more attacks on symbiotic L(2) (the second instar), aposymbiotic L(3) (the third instar) and L(4) (the forth instar) hosts than on the corresponding hosts at the same age. L. ambiguus also parasitized more L(1) aphids compared with adults irrespective of whether the aphid was asymbiotic or not. Pupa mortality rate of parasitoid progeny was significantly lower from aposymbiotic hosts than from the corresponding symbiotics at all stages. Female-biased parasitoid progeny was produced from aposymbiotic aphids without respect to host ages, but female progeny increased linearly with host ages at parasitism from symbiotic aphids. Body size of parasitoid progeny increased linearly with host instars at parasitism in symbiotic aphids but did not significantly change across host instars in aposymbiotic aphids. The offspring parasitoids turned out to be generally large in body size from attacking aposymbiotic aphids compared with the symbiotics. Development time of egg-to-adult of parasitoid progeny decreased with host instars in both symbiotic and aposymbiotic aphids but was generally much longer in aposymbiotic aphids than in symbiotic aphids. Our study suggests that age or body size of host aphids may not be the only cue exercised by L. ambiguus to evaluate host quality and that offspring parasitoids may be able to compensate for the nutrition stress associated with disruption of primary endosymbiotc bacteria in aposymbiotic aphids.

  8. Infection and invasion of roots by symbiotic, nitrogen-fixing rhizobia during nodulation of temperate legumes.

    Science.gov (United States)

    Gage, Daniel J

    2004-06-01

    Bacteria belonging to the genera Rhizobium, Mesorhizobium, Sinorhizobium, Bradyrhizobium, and Azorhizobium (collectively referred to as rhizobia) grow in the soil as free-living organisms but can also live as nitrogen-fixing symbionts inside root nodule cells of legume plants. The interactions between several rhizobial species and their host plants have become models for this type of nitrogen-fixing symbiosis. Temperate legumes such as alfalfa, pea, and vetch form indeterminate nodules that arise from root inner and middle cortical cells and grow out from the root via a persistent meristem. During the formation of functional indeterminate nodules, symbiotic bacteria must gain access to the interior of the host root. To get from the outside to the inside, rhizobia grow and divide in tubules called infection threads, which are composite structures derived from the two symbiotic partners. This review focuses on symbiotic infection and invasion during the formation of indeterminate nodules. It summarizes root hair growth, how root hair growth is influenced by rhizobial signaling molecules, infection of root hairs, infection thread extension down root hairs, infection thread growth into root tissue, and the plant and bacterial contributions necessary for infection thread formation and growth. The review also summarizes recent advances concerning the growth dynamics of rhizobial populations in infection threads.

  9. Distinct bacterial communities associated with the coral model Aiptasia in aposymbiotic and symbiotic states with Symbiodinium

    Directory of Open Access Journals (Sweden)

    Till Roethig

    2016-11-01

    Full Text Available Coral reefs are in decline. The basic functional unit of coral reefs is the coral metaorganism or holobiont consisting of the cnidarian host animal, symbiotic algae of the genus Symbiodinium, and a specific consortium of bacteria (among others, but research is slow due to the difficulty of working with corals. Aiptasia has proven a tractable model system to elucidate the intricacies of cnidarian-dinoflagellate symbioses, but characterization of the associated bacterial microbiome and the underlying genomic features relevant for bacterial selection and control is required to provide a complete and integrated understanding of holobiont function. In this work, we characterize and analyze the microbiome of aposymbiotic and symbiotic Aiptasia and show that bacterial associates are distinct in both conditions. We further show that key microbial associates can be cultured without their cnidarian host. Our results suggest that bacteria play an important role in the symbiosis of Aiptasia with Symbiodinium, a finding that underlines the power of the Aiptasia model system where cnidarian hosts can be analyzed in aposymbiotic and symbiotic states. The characterization of the native microbiome and the ability to retrieve culturable isolates contributes to the resources available for the Aiptasia model system. This provides an opportunity to comparatively analyze cnidarian metaorganisms as collective functional holobionts and as separated member species. We hope that this will accelerate research into understanding the intricacies of coral biology, which is urgently needed to develop strategies to mitigate the effects of environmental change.

  10. Distinct Bacterial Communities Associated with the Coral Model Aiptasia in Aposymbiotic and Symbiotic States with Symbiodinium

    KAUST Repository

    Röthig, Till

    2016-11-18

    Coral reefs are in decline. The basic functional unit of coral reefs is the coral metaorganism or holobiont consisting of the cnidarian host animal, symbiotic algae of the genus Symbiodinium, and a specific consortium of bacteria (among others), but research is slow due to the difficulty of working with corals. Aiptasia has proven to be a tractable model system to elucidate the intricacies of cnidarian-dinoflagellate symbioses, but characterization of the associated bacterial microbiome is required to provide a complete and integrated understanding of holobiont function. In this work, we characterize and analyze the microbiome of aposymbiotic and symbiotic Aiptasia and show that bacterial associates are distinct in both conditions. We further show that key microbial associates can be cultured without their cnidarian host. Our results suggest that bacteria play an important role in the symbiosis of Aiptasia with Symbiodinium, a finding that underlines the power of the Aiptasia model system where cnidarian hosts can be analyzed in aposymbiotic and symbiotic states. The characterization of the native microbiome and the ability to retrieve culturable isolates contributes to the resources available for the Aiptasia model system. This provides an opportunity to comparatively analyze cnidarian metaorganisms as collective functional holobionts and as separated member species. We hope that this will accelerate research into understanding the intricacies of coral biology, which is urgently needed to develop strategies to mitigate the effects of environmental change.

  11. The Effects of Probiotics and Symbiotics on Risk Factors for Hepatic Encephalopathy: A Systematic Review.

    Science.gov (United States)

    Viramontes Hörner, Daniela; Avery, Amanda; Stow, Ruth

    2017-04-01

    Alterations in the levels of intestinal microbiota, endotoxemia, and inflammation are novel areas of interest in the pathogenesis of hepatic encephalopathy (HE). Probiotics and symbiotics are a promising treatment option for HE due to possible beneficial effects in modulating gut microflora and might be better tolerated and more cost-effective than the traditional treatment with lactulose, rifaximin or L-ornithine-L-aspartate. A systematic search of the electronic databases PubMed, ISI Web of Science, EMBASE, and Cochrane Library was conducted for randomized controlled clinical trials in adult patients with cirrhosis, evaluating the effect of probiotics and symbiotics in changes on intestinal microflora, reduction of endotoxemia, inflammation, and ammonia, reversal of minimal hepatic encephalopathy (MHE), prevention of overt hepatic encephalopathy (OHE), and improvement of quality of life. Nineteen trials met the inclusion criteria. Probiotics and symbiotics increased beneficial microflora and decreased pathogenic bacteria and endotoxemia compared with placebo/no treatment, but no effect was observed on inflammation. Probiotics significantly reversed MHE [risk ratio, 1.53; 95% confidence interval (CI): 1.14, 2.05; P=0.005] and reduced OHE development (risk ratio, 0.62; 95% CI: 0.48, 0.80; P=0.0002) compared with placebo/no treatment. Symbiotics significantly decreased ammonia levels compared with placebo (15.24; 95% CI: -26.01, -4.47; P=0.006). Probiotics did not show any additional benefit on reversal of MHE and prevention of OHE development when compared with lactulose, rifaximin, and L-ornithine-L-aspartate. Only 5 trials considered tolerance with minimal side effects reported. Although further research is warranted, probiotics and symbiotics should be considered as an alternative therapy for the treatment and management of HE given the results reported in this systematic review.

  12. Enhanced Symbiotic Performance by Rhizobium tropici Glycogen Synthase Mutants

    Science.gov (United States)

    Marroquí, Silvia; Zorreguieta, Angeles; Santamaría, Carmen; Temprano, Francisco; Soberón, Mario; Megías, Manuel; Downie, J. Allan

    2001-01-01

    We isolated a Tn5-induced Rhizobium tropici mutant that has enhanced capacity to oxidize N,N-dimethyl-p-phenylendiamine (DMPD) and therefore has enhanced respiration via cytochrome oxidase. The mutant had increased levels of the cytochromes c1 and CycM and a small increase in the amount of cytochrome aa3. In plant tests, the mutant increased the dry weight of Phaseolus vulgaris plants by 20 to 38% compared with the control strain, thus showing significantly enhanced symbiotic performance. The predicted product of the mutated gene is homologous to glycogen synthases from several bacteria, and the mutant lacked glycogen. The DNA sequence of the adjacent gene region revealed six genes predicted to encode products homologous to the following gene products from Escherichia coli: glycogen phosphorylase (glgP), glycogen branching enzyme (glgB), ADP glucose pyrophosphorylase (glgC), glycogen synthase (glgA), phosphoglucomutase (pgm), and glycogen debranching enzyme (glgX). All six genes are transcribed in the same direction, and analysis with lacZ gene fusions suggests that the first five genes are organized in one operon, although pgm appears to have an additional promoter; glgX is transcribed independently. Surprisingly, the glgA mutant had decreased levels of high-molecular-weight exopolysaccharide after growth on glucose, but levels were normal after growth on galactose. A deletion mutant was constructed in order to generate a nonpolar mutation in glgA. This mutant had a phenotype similar to that of the Tn5 mutant, indicating that the enhanced respiration and symbiotic nitrogen fixation and decreased exopolysaccharide were due to mutation of glgA and not to a polar effect on a downstream gene. PMID:11208782

  13. Genetic Diversity and Symbiotic Efficiency of Indigenous Common Bean Rhizobia in Croatia

    Directory of Open Access Journals (Sweden)

    Ines Pohajda

    2016-01-01

    Full Text Available Nodule bacteria (rhizobia in symbiotic associations with legumes enable considerable entries of biologically fixed nitrogen into soil. Efforts are therefore made to intensify the natural process of symbiotic nitrogen fixation by legume inoculation. Studies of field populationsof rhizobia open up the possibility to preserve and probably exploit some indigenous strains with hidden symbiotic or ecological potentials. The main aim of the present study is to determine genetic diversity of common bean rhizobia isolated from different field sites in central Croatia and to evaluate their symbiotic efficiency and compatibility with host plants. The isolation procedure revealed that most soil samples contained no indigenous common bean rhizobia. The results indicate that the cropping history had a significant impact on the presence of indigenous strains. Although all isolates were found to belong to species Rhizobium leguminosarum, significant genetic diversity at the strain level was determined. Application of both random amplifi cation of polymorphic DNA (RAPD and enterobacterial repetitive intergenic consensus–polymerase chain reaction (ERIC-PCR methods resulted in similar grouping of strains. Symbiotic efficiency of indigenous rhizobia as well as their compatibility with two commonly grown bean varieties were tested in field experiments. Application of indigenous rhizobial strains as inoculants resulted in significantly different values of nodulation, seed yield as well as plant nitrogen and seed protein contents. The most abundant nodulation and the highest plant nitrogen and protein contents were determined in plants inoculated with R. leguminosarum strains S17/2 and S21/6. Although, in general, the inoculation had a positive impact on seed yield, differences depending on the applied strain were not determined. The overall results show the high degree of symbiotic efficiency of the specific indigenous strain S21/6. These results indicate different

  14. Toxic effects of arsenic on Sinorhizobium-Medicago sativa symbiotic interaction.

    Science.gov (United States)

    Pajuelo, Eloísa; Rodríguez-Llorente, Ignacio D; Dary, Mohammed; Palomares, Antonio J

    2008-07-01

    Recently, the Rhizobium-legume symbiotic interaction has been proposed as an interesting tool in bioremediation. However, little is known about the effect of most common contaminants on this process. The phytotoxic effects of arsenic on nodulation of Medicago sativa have been examined in vitro using the highly arsenic resistant and symbiotically effective Sinorhizobium sp. strain MA11. The bacteria were able to grow on plates containing As concentrations as high as 10 mM. Nevertheless, as little as 25-35 microM arsenite produced a 75% decrease in the total number of nodules, due to a 90% reduction in the number of rhizobial infections, as could be determined using the strain MA11 carrying a lacZ reporter gene. This effect was associated to root hair damage and a shorter infective root zone. However, once nodulation was established nodule development seemed to continue normally, although earlier senescence could be observed in nodules of arsenic-grown plants.

  15. Cell division and density of symbiotic Chlorella variabilis of the ciliate Paramecium bursaria is controlled by the host's nutritional conditions during early infection process.

    Science.gov (United States)

    Kodama, Yuuki; Fujishima, Masahiro

    2012-10-01

    The association of ciliate Paramecium bursaria with symbiotic Chlorella sp. is a mutualistic symbiosis. However, both the alga-free paramecia and symbiotic algae can still grow independently and can be reinfected experimentally by mixing them. Effects of the host's nutritional conditions against the symbiotic algal cell division and density were examined during early reinfection. Transmission electron microscopy revealed that algal cell division starts 24 h after mixing with alga-free P. bursaria, and that the algal mother cell wall is discarded from the perialgal vacuole membrane, which encloses symbiotic alga. Labelling of the mother cell wall with Calcofluor White Stain, a cell-wall-specific fluorochrome, was used to show whether alga had divided or not. Pulse labelling of alga-free P. bursaria cells with Calcofluor White Stain-stained algae with or without food bacteria for P. bursaria revealed that the fluorescence of Calcofluor White Stain in P. bursaria with bacteria disappeared within 3 days after mixing, significantly faster than without bacteria. Similar results were obtained both under constant light and dark conditions. This report is the first describing that the cell division and density of symbiotic algae of P. bursaria are controlled by the host's nutritional conditions during early infection. © 2012 Society for Applied Microbiology and Blackwell Publishing Ltd.

  16. Symbiotic options for the conquest of land.

    Science.gov (United States)

    Field, Katie J; Pressel, Silvia; Duckett, Jeffrey G; Rimington, William R; Bidartondo, Martin I

    2015-08-01

    The domination of the landmasses of Earth by plants starting during the Ordovician Period drastically altered the development of the biosphere and the composition of the atmosphere, with far-reaching consequences for all life ever since. It is widely thought that symbiotic soil fungi facilitated the colonization of the terrestrial environment by plants. However, recent discoveries in molecular ecology, physiology, cytology, and paleontology have brought into question the hitherto-assumed identity and biology of the fungi engaged in symbiosis with the earliest-diverging lineages of extant land plants. Here, we reconsider the existing paradigm and show that the symbiotic options available to the first plants emerging onto the land were more varied than previously thought. Copyright © 2015 Elsevier Ltd. All rights reserved.

  17. Symbiotic options for the conquest of land

    OpenAIRE

    Field, KJ; Pressel, S; Duckett, JG; Rimington, WR; Bidartondo, MI

    2015-01-01

    The domination of the landmasses of Earth by plants starting during the Ordovician Period drastically altered the development of the biosphere and the composition of the atmosphere, with far-reaching consequences for all life ever since. It is widely thought that symbiotic soil fungi facilitated the colonization of the terrestrial environment by plants. However, recent discoveries in molecular ecology, physiology, cytology, and paleontology have brought into question the hitherto-assumed iden...

  18. Physical Structure of Four Symbiotic Binaries

    Science.gov (United States)

    Kenyon, Scott J. (Principal Investigator)

    1997-01-01

    Disk accretion powers many astronomical objects, including pre-main sequence stars, interacting binary systems, and active galactic nuclei. Unfortunately, models developed to explain the behavior of disks and their surroundings - boundary layers, jets, and winds - lack much predictive power, because the physical mechanism driving disk evolution - the viscosity - is not understood. Observations of many types of accreting systems are needed to constrain the basic physics of disks and provide input for improved models. Symbiotic stars are an attractive laboratory for studying physical phenomena associated with disk accretion. These long period binaries (P(sub orb) approx. 2-3 yr) contain an evolved red giant star, a hot companion, and an ionized nebula. The secondary star usually is a white dwarf accreting material from the wind of its red giant companion. A good example of this type of symbiotic is BF Cygni: our analysis shows that disk accretion powers the nuclear burning shell of the hot white dwarf and also manages to eject material perpendicular to the orbital plane (Mikolajewska, Kenyon, and Mikolajewski 1989). The hot components in other symbiotic binaries appear powered by tidal overflow from a very evolved red giant companion. We recently completed a study of CI Cygni and demonstrated that the accreting secondary is a solar-type main sequence star, rather than a white dwarf (Kenyon et aL 1991). This project continued our study of symbiotic binary systems. Our general plan was to combine archival ultraviolet and optical spectrophotometry with high quality optical radial velocity observations to determine the variation of line and continuum sources as functions of orbital phase. We were very successful in generating orbital solutions and phasing UV+optical spectra for five systems: AG Dra, V443 Her, RW Hya, AG Peg, and AX Per. Summaries of our main results for these systems appear below. A second goal of our project was to consider general models for the

  19. Phylogenetic diversity of bacteria associated with toxic and non-toxic ...

    African Journals Online (AJOL)

    Phylogenetic diversity of bacteria associated with toxic and non-toxic strains of Alexandrium minutum. L Palacios, B Reguera, J Franco, I Marín. Abstract. Marine planktonic dinoflagellates are usually associated with bacteria, some of which seem to have a symbiotic relation with the dinoflagellate cells. The role of bacteria in ...

  20. Investigating Tactile Stimulation in Symbiotic Systems

    DEFF Research Database (Denmark)

    Orso, Valeria; Mazza, Renato; Gamberini, Luciano

    2017-01-01

    The core characteristics of tactile stimuli, i.e., recognition reliability and tolerance to ambient interference, make them an ideal candidate to be integrated into a symbiotic system. The selection of the appropriate stimulation is indeed important in order not to hinder the interaction from...... the user’s perspective. Here we present the process of selecting the most adequate tactile stimulation delivered by a tactile vest while users were engaged in an absorbing activity, namely playing a video-game. A total of 20 participants (mean age 24.78; SD= 1.57) were involved. Among the eight tactile...

  1. Symbiotic regulation of plant growth, development and reproduction

    Science.gov (United States)

    Russell J. Rodriguez; D. Carl Freeman; E. Durant McArthur; Yong Ok Kim; Regina S. Redman

    2009-01-01

    The growth and development of rice (Oryzae sativa) seedlings was shown to be regulated epigenetically by a fungal endophyte. In contrast to un-inoculated (nonsymbiotic) plants, endophyte colonized (symbiotic) plants preferentially allocated resources into root growth until root hairs were well established. During that time symbiotic roots expanded at...

  2. Eco-physiological responses and symbiotic nitrogen fixation ...

    African Journals Online (AJOL)

    Administrator

    2010-11-01

    Nov 1, 2010 ... Nitrogen nutrition of Hedysarum carnosum, a pastoral legume common in Tunisian central and southern rangelands ... Despite the fact that Na+ accumulation decreased plant growth, both nodulation and symbiotic nitrogen fixation capacity of H. ... of the symbiotic interaction as well as nodule development.

  3. Symbiotic effectiveness of acid-tolerant Bradyrhizobium strains with ...

    African Journals Online (AJOL)

    Further, symbiotic effectiveness of these strains was determined under the polyhouse conditions in sterilized soil (pH 4.5). Highest and lowest symbiotic characters, dry matter production and nitrogen improvement per plant were observed in PSR001 and NSR008 inoculated plants, respectively. All the examined isolates ...

  4. [Metabolic integration of organisms within symbiotic systems].

    Science.gov (United States)

    Provorov, N A; Dolgikh, E A

    2006-01-01

    Adaptation of organisms to coexisence in symbiotic systems is usually related to significant metabolic changes resulting in the integration of the biochemical pathways of the partners. In the symbioses between plants and nitrogen-fixing organisms, between heterotrophic and autotrophic organisms, as well as between animals and microorganisms providing the consumption of plant biomass, the systems of C- and N-metabolism, controlling the utilization of various sources of nitrogen (N2, organic and inorganic compounds, metabolic waste of the host) and carbon (CO2, plant polymers), of the partners are tightly integrated. Bilateral biochemical links between partners are typical to mutualistic symbioses (wherein biotrophic nutrition predominates, in some cases including necrotrophy of secondary origin). In antagonistic symbioses, unilateral links predominate, though active assimilation of the pathogen's secondary metabolites by the host is also possible. In most mutualistic symbioses, integrated metabolic ties have derived from trophic chains in biocenoses (syntrophic consortia, "predator-prey" systems), but not from the systems where the pathogens consume host metabolites. At the same time, molecular analysis of symbiotic interactions has shown that symbioses considerably differ from biocenoses, where the cycling of nutrients and energy implies no functional integration of the partner's genes.

  5. CIRCUMSTELLAR SHELL FORMATION IN SYMBIOTIC RECURRENT NOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Moore, Kevin; Bildsten, Lars [Department of Physics, Broida Hall, University of California, Santa Barbara, CA 93106 (United States)

    2012-12-20

    We present models of spherically symmetric recurrent nova shells interacting with circumstellar material (CSM) in a symbiotic system composed of a red giant (RG) expelling a wind and a white dwarf accreting from this material. Recurrent nova eruptions periodically eject material at high velocities ({approx}> 10{sup 3} km s{sup -1}) into the RG wind profile, creating a decelerating shock wave as CSM is swept up. High CSM densities cause the shocked wind and ejecta to have very short cooling times of days to weeks. Thus, the late-time evolution of the shell is determined by momentum conservation instead of energy conservation. We compute and show evolutionary tracks of shell deceleration, as well as post-shock structure. After sweeping up all the RG wind, the shell coasts at a velocity {approx}100 km s{sup -1}, depending on system parameters. These velocities are similar to those measured in blueshifted CSM from the symbiotic nova RS Oph, as well as a few Type Ia supernovae that show evidence of CSM, such as 2006X, 2007le, and PTF 11kx. Supernovae occurring in such systems may not show CSM interaction until the inner nova shell gets hit by the supernova ejecta, days to months after the explosion.

  6. Developing symbiotic consortia for lignocellulosic biofuel production

    Energy Technology Data Exchange (ETDEWEB)

    Zuroff, Trevor R.; Curtis, Wayne R. [Pennsylvania State Univ., University Park, PA (United States). Dept. of Chemical Engineering

    2012-02-15

    The search for petroleum alternatives has motivated intense research into biological breakdown of lignocellulose to produce liquid fuels such as ethanol. Degradation of lignocellulose for biofuel production is a difficult process which is limited by, among other factors, the recalcitrance of lignocellulose and biological toxicity of the products. Consolidated bioprocessing has been suggested as an efficient and economical method of producing low value products from lignocellulose; however, it is not clear whether this would be accomplished more efficiently with a single organism or community of organisms. This review highlights examples of mixtures of microbes in the context of conceptual models for developing symbiotic consortia for biofuel production from lignocellulose. Engineering a symbiosis within consortia is a putative means of improving both process efficiency and stability relative to monoculture. Because microbes often interact and exist attached to surfaces, quorum sensing and biofilm formation are also discussed in terms of consortia development and stability. An engineered, symbiotic culture of multiple organisms may be a means of assembling a novel combination of metabolic capabilities that can efficiently produce biofuel from lignocellulose. (orig.)

  7. Monogamy in a Hyper-Symbiotic Shrimp.

    Directory of Open Access Journals (Sweden)

    J Antonio Baeza

    Full Text Available Theory predicts that monogamy is adaptive in resource-specialist symbiotic crustaceans inhabiting relatively small and morphologically simple hosts in tropical environments where predation risk away from hosts is high. We tested this prediction in Pontonia manningi, a hyper-symbiotic shrimp that dwells in the mantle cavity of the Atlantic winged oyster Pteria colymbus that, in turn, infects gorgonians from the genus Pseudopterogorgia in the Caribbean Sea. In agreement with theory, P. manningi were found dwelling as heterosexual pairs in oysters more frequently than expected by chance alone. Males and females also inhabited the same host individual independent of the female gravid condition or of the developmental stage of brooded embryos. While the observations above argue in favor of monogamy in P. manningi, there is evidence to suggest that males of the studied species are moderately promiscuous. That females found living solitary in oysters most often brooded embryos, and that males allocated more to weaponry (major claw size than females at any given size suggest that males might be roaming among host individuals in search of and, fighting for, receptive females. All available information depicts a rather complex mating system in P. manningi: primarily monogamous but with moderately promiscuous males.

  8. Symbiotic essential amino acids provisioning in the American cockroach, Periplaneta americana (Linnaeus under various dietary conditions

    Directory of Open Access Journals (Sweden)

    Paul A. Ayayee

    2016-05-01

    Full Text Available Insect gut microbes have been shown to provide nutrients such as essential amino acids (EAAs to their hosts. How this symbiotic nutrient provisioning tracks with the host’s demand is not well understood. In this study, we investigated microbial essential amino acid (EAA provisioning in omnivorous American cockroaches (Periplaneta americana, fed low-quality (LQD and comparatively higher-quality dog food (DF diets using carbon stable isotope ratios of EAAs (δ13CEAA. We assessed non-dietary EAA input, quantified as isotopic offsets (Δ13C between cockroach (δ13CCockroach EAA and dietary (δ13CDietary EAA EAAs, and subsequently determined biosynthetic origins of non-dietary EAAs in cockroaches using 13C-fingerprinting with dietary and representative bacterial and fungal δ13CEAA. Investigation of biosynthetic origins of de novo non-dietary EAAs indicated bacterial origins of EAA in cockroach appendage samples, and a mixture of fungal and bacterial EAA origins in gut filtrate samples for both LQD and DF-fed groups. We attribute the bacteria-derived EAAs in cockroach appendages to provisioning by the fat body residing obligate endosymbiont, Blattabacterium and gut-residing bacteria. The mixed signatures of gut filtrate samples are attributed to the presence of unassimilated dietary, as well as gut microbial (bacterial and fungal EAAs. This study highlights the potential impacts of dietary quality on symbiotic EAA provisioning and the need for further studies investigating the interplay between host EAA demands, host dietary quality and symbiotic EAA provisioning in response to dietary sufficiency or deficiency.

  9. Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium "Candidatus Holospora parva".

    Directory of Open Access Journals (Sweden)

    Olivia Lanzoni

    Full Text Available Ciliated protists often form symbioses with many diverse microorganisms. In particular, symbiotic associations between ciliates and green algae, as well as between ciliates and intracellular bacteria, are rather wide-spread in nature. In this study, we describe the complex symbiotic system between a very rare ciliate, Paramecium chlorelligerum, unicellular algae inhabiting its cytoplasm, and novel bacteria colonizing the host macronucleus. Paramecium chlorelligerum, previously found only twice in Germany, was retrieved from a novel location in vicinity of St. Petersburg in Russia. Species identification was based on both classical morphological methods and analysis of the small subunit rDNA. Numerous algae occupying the cytoplasm of this ciliate were identified with ultrastructural and molecular methods as representatives of the Meyerella genus, which before was not considered among symbiotic algae. In the same locality at least fifteen other species of "green" ciliates were found, thus it is indeed a biodiversity hot-spot for such protists. A novel species of bacterial symbionts living in the macronucleus of Paramecium chlorelligerum cells was morphologically and ultrastructurally investigated in detail with the description of its life cycle and infection capabilities. The new endosymbiont was molecularly characterized following the full-cycle rRNA approach. Furthermore, phylogenetic analysis confirmed that the novel bacterium is a member of Holospora genus branching basally but sharing all characteristics of the genus except inducing connecting piece formation during the infected host nucleus division. We propose the name "Candidatus Holospora parva" for this newly described species. The described complex system raises new questions on how these microorganisms evolve and interact in symbiosis.

  10. Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium "Candidatus Holospora parva".

    Science.gov (United States)

    Lanzoni, Olivia; Fokin, Sergei I; Lebedeva, Natalia; Migunova, Alexandra; Petroni, Giulio; Potekhin, Alexey

    2016-01-01

    Ciliated protists often form symbioses with many diverse microorganisms. In particular, symbiotic associations between ciliates and green algae, as well as between ciliates and intracellular bacteria, are rather wide-spread in nature. In this study, we describe the complex symbiotic system between a very rare ciliate, Paramecium chlorelligerum, unicellular algae inhabiting its cytoplasm, and novel bacteria colonizing the host macronucleus. Paramecium chlorelligerum, previously found only twice in Germany, was retrieved from a novel location in vicinity of St. Petersburg in Russia. Species identification was based on both classical morphological methods and analysis of the small subunit rDNA. Numerous algae occupying the cytoplasm of this ciliate were identified with ultrastructural and molecular methods as representatives of the Meyerella genus, which before was not considered among symbiotic algae. In the same locality at least fifteen other species of "green" ciliates were found, thus it is indeed a biodiversity hot-spot for such protists. A novel species of bacterial symbionts living in the macronucleus of Paramecium chlorelligerum cells was morphologically and ultrastructurally investigated in detail with the description of its life cycle and infection capabilities. The new endosymbiont was molecularly characterized following the full-cycle rRNA approach. Furthermore, phylogenetic analysis confirmed that the novel bacterium is a member of Holospora genus branching basally but sharing all characteristics of the genus except inducing connecting piece formation during the infected host nucleus division. We propose the name "Candidatus Holospora parva" for this newly described species. The described complex system raises new questions on how these microorganisms evolve and interact in symbiosis.

  11. Characterization of goat milk and potentially symbiotic non-fat yogurt

    Directory of Open Access Journals (Sweden)

    Noelia Fernanda Paz

    2014-09-01

    Full Text Available Combining prebiotics and probiotic microorganisms improve quality in the formulation of foods. In this paper, the characteristics of goat milk and symbiotic yogurt were studied. Raw goat milk was analyzed and the skimming process was optimized. For the formulation of a potentially non-fat symbiotic yogurt made with skimmed goat milk, inulin, gelatin, sugar, and Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei subsp. rhamnoshus. Chemical characteristics, acceptability, and viability of lactic acid bacteria and probiotic culture were assessed. The protein and fat content of the raw milk was 2.90 and 3.56 g/100 mL, respectively. The optimum skimming process was obtained at 9,800 rpm and 4 °C for 15 minutes. The product formulated had a protein and fat content of 4.04 to 0.04 g/100 mL, good sensory properties, and acceptability of 95%. The lactic bacteria count was 9 × 10(7 CFU mL- 1, and probiotic culture count was higher than 1 × 10(6 CFU mL- 1, which guarantees their effect and capacity to survive in the digestive tract and spread in the intestine. The yogurt was stable during the 21 days of storage. Therefore, this study shows that goat milk yogurt is an adequate delivery vehicle of the probiotic culture L. casei and inulin.

  12. Pesticides reduce symbiotic efficiency of nitrogen-fixing rhizobia and host plants.

    Science.gov (United States)

    Fox, Jennifer E; Gulledge, Jay; Engelhaupt, Erika; Burow, Matthew E; McLachlan, John A

    2007-06-12

    Unprecedented agricultural intensification and increased crop yield will be necessary to feed the burgeoning world population, whose global food demand is projected to double in the next 50 years. Although grain production has doubled in the past four decades, largely because of the widespread use of synthetic nitrogenous fertilizers, pesticides, and irrigation promoted by the "Green Revolution," this rate of increased agricultural output is unsustainable because of declining crop yields and environmental impacts of modern agricultural practices. The last 20 years have seen diminishing returns in crop yield in response to increased application of fertilizers, which cannot be completely explained by current ecological models. A common strategy to reduce dependence on nitrogenous fertilizers is the production of leguminous crops, which fix atmospheric nitrogen via symbiosis with nitrogen-fixing rhizobia bacteria, in rotation with nonleguminous crops. Here we show previously undescribed in vivo evidence that a subset of organochlorine pesticides, agrichemicals, and environmental contaminants induces a symbiotic phenotype of inhibited or delayed recruitment of rhizobia bacteria to host plant roots, fewer root nodules produced, lower rates of nitrogenase activity, and a reduction in overall plant yield at time of harvest. The environmental consequences of synthetic chemicals compromising symbiotic nitrogen fixation are increased dependence on synthetic nitrogenous fertilizer, reduced soil fertility, and unsustainable long-term crop yields.

  13. Kinematics of the symbiotic system R Aqr

    Science.gov (United States)

    Navarro, S.; Corral, L. J.; Steffen, W.

    2014-04-01

    We present the results of the kinematical analysis of the symbiotic system R Aqr. We obtained high dispersion spectra with the MES spectrograph at the 2.1 m telescope of San Pedro Mártir (MEZCAL). The used filter were Ha + [NII], (λc = 6575Å, Δλ = 90Å). We analyse the [NII] λλ6583 line. When the observations are compared with previous ones by Solf (1992) we detected an important change in the projected velocities of the observed knots, supporting the idea of a precessing jet. We are working also in a 3-D kinematic model for the object using the measured velocities and the state of the model is presented.

  14. Metagenomic analysis of the pinewood nematode microbiome reveals a symbiotic relationship critical for xenobiotics degradation

    Science.gov (United States)

    Cheng, Xin-Yue; Tian, Xue-Liang; Wang, Yun-Sheng; Lin, Ren-Miao; Mao, Zhen-Chuan; Chen, Nansheng; Xie, Bing-Yan

    2013-01-01

    Our recent research revealed that pinewood nematode (PWN) possesses few genes encoding enzymes for degrading α-pinene, which is the main compound in pine resin. In this study, we examined the role of PWN microbiome in xenobiotics detoxification by metagenomic and bacteria culture analyses. Functional annotation of metagenomes illustrated that benzoate degradation and its related metabolisms may provide the main metabolic pathways for xenobiotics detoxification in the microbiome, which is obviously different from that in PWN that uses cytochrome P450 metabolism as the main pathway for detoxification. The metabolic pathway of degrading α-pinene is complete in microbiome, but incomplete in PWN genome. Experimental analysis demonstrated that most of tested cultivable bacteria can not only survive the stress of 0.4% α-pinene, but also utilize α-pinene as carbon source for their growth. Our results indicate that PWN and its microbiome have established a potentially mutualistic symbiotic relationship with complementary pathways in detoxification metabolism. PMID:23694939

  15. Distinguishing between symbiotic stars and planetary nebulae

    Science.gov (United States)

    Iłkiewicz, K.; Mikołajewska, J.

    2017-10-01

    Context. The number of known symbiotic stars (SySt) is still significantly lower than their predicted population. One of the main problems in finding the total population of SySt is the fact that their spectrum can be confused with other objects, such as planetary nebulae (PNe) or dense H II regions. This problem is reinforced by the fact that in a significant fraction of established SySt the emission lines used to distinguish them from other objects are not present. Aims: We aim at finding new diagnostic diagrams that could help separate SySt from PNe. Additionally, we examine a known sample of extragalactic PNe for candidate SySt. Methods: We employed emission line fluxes of known SySt and PNe from the literature. Results: We found that among the forbidden lines in the optical region of spectrum, only the [O III] and [N II] lines can be used as a tool for distinguishing between SySt and PNe, which is consistent with the fact that they have the highest critical densities. The most useful diagnostic that we propose is based on He I lines, which are more common and stronger in SySt than forbidden lines. All these useful diagnostic diagrams are electron density indicators that better distinguish PNe and ionized symbiotic nebulae. Moreover, we found six new candidate SySt in the Large Magellanic Cloud and one in M 81. If confirmed, the candidate in M 81 would be the farthest known SySt thus far.

  16. Symbiote transmission and maintenance of extra-genomic associations

    Directory of Open Access Journals (Sweden)

    Benjamin Minault Fitzpatrick

    2014-02-01

    Full Text Available Symbiotes can be transmitted from parents to offspring or horizontally from unrelated hosts or the environment. A key question is whether symbiote transmission is similar enough to Mendelian gene transmission to generate and maintain coevolutionary associations between host and symbiote genes. Recent papers come to opposite conclusions, with some suggesting that any horizontal transmission eliminates genetic association. These studies are hard to compare owing to arbitrary differences in modeling approach, parameter values, and assumptions about selection. I show that associations between host and symbiote genes (extra-genomic associations can be described by the same dynamic model as conventional linkage disequilibria between genes in the same genome. Thus, covariance between host and symbiote genomes depends on population history, geographic structure, selection, and co-transmission rate, just as covariance between genes within a genome. The conclusion that horizontal transmission rapidly erodes extra-genomic associations is equivalent to the conclusion that recombination rapidly erodes associations between genes within a genome. The conclusion is correct in the absence of population structure or selection. However, population structure can maintain spatial associations between host and symbiote traits, and non-additive selection (interspecific epistasis can generate covariances between host and symbiote genotypes. These results can also be applied to cultural or other nongenetic traits. This work contributes to a growing consensus that genomic, symbiotic, and gene-culture evolution can be analyzed under a common theoretical framework. In terms of coevolutionary potential, symbiotes can be viewed as lying on a continuum between the intimacy of genes and the indifference of casually co-occuring species.

  17. Phylogeny of nodulation genes and symbiotic diversity of Acacia senegal (L.) Willd. and A. seyal (Del.) Mesorhizobium strains from different regions of Senegal.

    Science.gov (United States)

    Bakhoum, Niokhor; Galiana, Antoine; Le Roux, Christine; Kane, Aboubacry; Duponnois, Robin; Ndoye, Fatou; Fall, Dioumacor; Noba, Kandioura; Sylla, Samba Ndao; Diouf, Diégane

    2015-04-01

    Acacia senegal and Acacia seyal are small, deciduous legume trees, most highly valued for nitrogen fixation and for the production of gum arabic, a commodity of international trade since ancient times. Symbiotic nitrogen fixation by legumes represents the main natural input of atmospheric N2 into ecosystems which may ultimately benefit all organisms. We analyzed the nod and nif symbiotic genes and symbiotic properties of root-nodulating bacteria isolated from A. senegal and A. seyal in Senegal. The symbiotic genes of rhizobial strains from the two Acacia species were closed to those of Mesorhizobium plurifarium and grouped separately in the phylogenetic trees. Phylogeny of rhizobial nitrogen fixation gene nifH was similar to those of nodulation genes (nodA and nodC). All A. senegal rhizobial strains showed identical nodA, nodC, and nifH gene sequences. By contrast, A. seyal rhizobial strains exhibited different symbiotic gene sequences. Efficiency tests demonstrated that inoculation of both Acacia species significantly affected nodulation, total dry weight, acetylene reduction activity (ARA), and specific acetylene reduction activity (SARA) of plants. However, these cross-inoculation tests did not show any specificity of Mesorhizobium strains toward a given Acacia host species in terms of infectivity and efficiency as stated by principal component analysis (PCA). This study demonstrates that large-scale inoculation of A. senegal and A. seyal in the framework of reafforestation programs requires a preliminary step of rhizobial strain selection for both Acacia species.

  18. Same, same but different: symbiotic bacterial associations in GBR sponges

    Directory of Open Access Journals (Sweden)

    Nicole S Webster

    2013-01-01

    Full Text Available Symbioses in marine sponges involve diverse consortia of microorganisms that contribute to the health and ecology of their hosts. The microbial communities of 13 taxonomically diverse Great Barrier Reef (GBR sponge species were assessed by DGGE and 16S rRNA gene sequencing to determine intra and inter species variation in bacterial symbiont composition. Microbial profiling revealed communities that were largely conserved within different individuals of each species with intra species similarity ranging from 65-100%. 16S rRNA gene sequencing revealed that the communities were dominated by Proteobacteria, Chloroflexi, Acidobacteria, Actinobacteria, Nitrospira and Cyanobacteria. Sponge-associated microbes were also highly host-specific with no operational taxonomic units (OTUs common to all species and the most ubiquitous OTU found in only 5 of the 13 sponge species. In total, 91% of the OTUs were restricted to a single sponge species. However, GBR sponge microbes were more closely related to other sponge-derived bacteria than they were to environmental communities with sequences falling within 50 of the 173 previously defined sponge-(or sponge-coral specific sequence clusters. These sequence clusters spanned the Acidobacteria, Actinobacteria, Proteobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Gemmatimonadetes, Nitrospira and the Planctomycetes-Verrucomicrobia-Chlamydiae superphylum. The number of sequences assigned to these sponge-specific clusters across all species ranged from 0% to 92%. No relationship between host phylogeny and symbiont communities were observed across the different sponge orders, although the highest level of similarity was detected in two closely related Xestospongia species. This study identifies the core microbial inhabitants in a range of GBR sponges thereby providing the basis for future studies on sponge symbiotic function and research aiming to predict how sponge holobionts will respond to environmental

  19. Same, same but different: symbiotic bacterial associations in GBR sponges.

    Science.gov (United States)

    Webster, N S; Luter, H M; Soo, R M; Botté, E S; Simister, R L; Abdo, D; Whalan, S

    2012-01-01

    Symbioses in marine sponges involve diverse consortia of microorganisms that contribute to the health and ecology of their hosts. The microbial communities of 13 taxonomically diverse Great Barrier Reef (GBR) sponge species were assessed by DGGE and 16S rRNA gene sequencing to determine intra and inter species variation in bacterial symbiont composition. Microbial profiling revealed communities that were largely conserved within different individuals of each species with intra species similarity ranging from 65-100%. 16S rRNA gene sequencing revealed that the communities were dominated by Proteobacteria, Chloroflexi, Acidobacteria, Actinobacteria, Nitrospira, and Cyanobacteria. Sponge-associated microbes were also highly host-specific with no operational taxonomic units (OTUs) common to all species and the most ubiquitous OTU found in only 5 of the 13 sponge species. In total, 91% of the OTUs were restricted to a single sponge species. However, GBR sponge microbes were more closely related to other sponge-derived bacteria than they were to environmental communities with sequences falling within 50 of the 173 previously defined sponge-(or sponge-coral) specific sequence clusters (SC). These SC spanned the Acidobacteria, Actinobacteria, Proteobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Gemmatimonadetes, Nitrospira, and the Planctomycetes-Verrucomicrobia-Chlamydiae superphylum. The number of sequences assigned to these sponge-specific clusters across all species ranged from 0 to 92%. No relationship between host phylogeny and symbiont communities were observed across the different sponge orders, although the highest level of similarity was detected in two closely related Xestospongia species. This study identifies the core microbial inhabitants in a range of GBR sponges thereby providing the basis for future studies on sponge symbiotic function and research aiming to predict how sponge holobionts will respond to environmental perturbation.

  20. Same, same but different: symbiotic bacterial associations in GBR sponges

    Science.gov (United States)

    Webster, N. S.; Luter, H. M.; Soo, R. M.; Botté, E. S.; Simister, R. L.; Abdo, D.; Whalan, S.

    2012-01-01

    Symbioses in marine sponges involve diverse consortia of microorganisms that contribute to the health and ecology of their hosts. The microbial communities of 13 taxonomically diverse Great Barrier Reef (GBR) sponge species were assessed by DGGE and 16S rRNA gene sequencing to determine intra and inter species variation in bacterial symbiont composition. Microbial profiling revealed communities that were largely conserved within different individuals of each species with intra species similarity ranging from 65–100%. 16S rRNA gene sequencing revealed that the communities were dominated by Proteobacteria, Chloroflexi, Acidobacteria, Actinobacteria, Nitrospira, and Cyanobacteria. Sponge-associated microbes were also highly host-specific with no operational taxonomic units (OTUs) common to all species and the most ubiquitous OTU found in only 5 of the 13 sponge species. In total, 91% of the OTUs were restricted to a single sponge species. However, GBR sponge microbes were more closely related to other sponge-derived bacteria than they were to environmental communities with sequences falling within 50 of the 173 previously defined sponge-(or sponge-coral) specific sequence clusters (SC). These SC spanned the Acidobacteria, Actinobacteria, Proteobacteria, Bacteroidetes, Chloroflexi, Cyanobacteria, Gemmatimonadetes, Nitrospira, and the Planctomycetes-Verrucomicrobia-Chlamydiae superphylum. The number of sequences assigned to these sponge-specific clusters across all species ranged from 0 to 92%. No relationship between host phylogeny and symbiont communities were observed across the different sponge orders, although the highest level of similarity was detected in two closely related Xestospongia species. This study identifies the core microbial inhabitants in a range of GBR sponges thereby providing the basis for future studies on sponge symbiotic function and research aiming to predict how sponge holobionts will respond to environmental perturbation. PMID:23346080

  1. Stress as a Normal Cue in the Symbiotic Environment.

    Science.gov (United States)

    Schwartzman, Julia A; Ruby, Edward G

    2016-05-01

    All multicellular hosts form associations with groups of microorganisms. These microbial communities can be taxonomically diverse and dynamic, and their persistence is due to robust, and sometimes coevolved, host-microbe and microbe-microbe interactions. Chemical and physical sources of stress are prominently situated in this molecular exchange, as cues for cellular responses in symbiotic microbes. Stress in the symbiotic environment may arise from three sources: host tissues, microbe-induced immune responses, or other microbes in the host environment. The responses of microbes to these stresses can be general or highly specialized, and collectively may contribute to the stability of the symbiotic system. In this review, we highlight recent work that emphasizes the role of stress as a cue in the symbiotic environment of plants and animals. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Symbiotic and phenotypic characterization of Rhizobium isolates of ...

    African Journals Online (AJOL)

    Pisum sativum L.) Fabaceae, from central and southern Ethiopia. ... and NSRlFP18 were the elite rhizobia that can be selected and further tested for their genetic and symbiotic performance in field trials for future bio-inoculant formulation.

  3. Symbiotic effectiveness of rhizobial mutualists varies in interactions with native Australian legume genera.

    Directory of Open Access Journals (Sweden)

    Peter H Thrall

    Full Text Available BACKGROUND AND OBJECTIVES: Interactions between plants and beneficial soil organisms (e.g. rhizobial bacteria, mycorrhizal fungi are models for investigating the ecological impacts of such associations in plant communities, and the evolution and maintenance of variation in mutualisms (e.g. host specificity and the level of benefits provided. With relatively few exceptions, variation in symbiotic effectiveness across wild host species is largely unexplored. METHODS: We evaluated these associations using representatives of several legume genera which commonly co-occur in natural ecosystems in south-eastern Australia and an extensive set of rhizobial strains isolated from these hosts. These strains had been previously assigned to specific phylotypes on the basis of molecular analyses. In the first of two inoculation experiments, the growth responses of each host species was evaluated with rhizobial strains isolated from that species. The second experiment assessed performance across genera and the extent of host specificity using a subset of these strains. RESULTS: While host growth responses to their own (sympatric isolates varied considerably, rhizobial phylotype was a significant predictor of symbiotic performance, indicating that bacterial species designations on the basis of molecular markers have ecological importance. Hosts responded in qualitatively different ways to sympatric and allopatric strains of rhizobia, ranging from species with a clear preference for their own strains, to those that were broad generalists, through to species that grew significantly better with allopatric strains. CONCLUSION: Theory has focused on trade-offs between the provision of benefits and symbiont competitive ability that might explain the persistence of less beneficial strains. However, differences in performance among co-occurring host species could also drive such patterns. Our results thus highlight the likely importance of plant community structure in

  4. Genetic Identification and Symbiotic Efficiency of an Indigenous Sinorhizobium meliloti Field Population

    Directory of Open Access Journals (Sweden)

    Sanja Sikora

    2003-01-01

    Full Text Available Soil bacteria Sinorhizobium meliloti are of enormous agricultural value, because of their ability to fix atmospheric nitrogen in symbiosis with an important forage crop legume – alfalfa. The main aim of this study was (i to isolate indigenous S. meliloti strains from different field sites in Croatia, (ii to assess genetic diversity and genetic relationships amongst strains of natural populations and (iii to provide information about nodulation and symbiotic efficiency of indigenous S. meliloti strains. The nine strains isolated from alfalfa nodules collected from different field sites and three reference strains were analysed. Genetic characterisation by PCR-RFLP of the 16S rDNA, rep-PCR and RAPD-PCR was applied to study the status of Sinorhizobium meliloti populations inhabiting nodules of alfalfa. The results of PCR-RFLP of the 16S rDNA revealed that all isolates belong to the S. meliloti species. Cluster analysis of rep-PCR and RAPD-PCR profiles showed significant differences among S. meliloti isolates. Both methods resulted in identical grouping of strains. Among indigenous strains two divergent groups could be determined. The biggest differences were detected among two reference strains and all field isolates. Greenhouse studies were performed for evaluation of symbiotic efficiency and compatibility of S. meliloti strains with two alfalfa cultivars. Quantitative expression of symbiotic efficiency was evaluated by measurement of nodule dry weight, content of proteins and total nitrogen in plants, dry matter and green mass yield of plants. All strains nodulated both alfalfa cultivars but with different efficiency. Significant differences in dry matter and green mass yield of alfalfa as well as protein content were determined depending on the strain used. The results indicate that three indigenous S. meliloti strains can be characterised as the most efficient of all strains used in this study.

  5. Legume-rhizobium symbiotic promiscuity and effectiveness do not affect plant invasiveness.

    Science.gov (United States)

    Keet, Jan-Hendrik; Ellis, Allan G; Hui, Cang; Le Roux, Johannes J

    2017-06-01

    The ability to fix atmospheric nitrogen is thought to play an important role in the invasion success of legumes. Interactions between legumes and nitrogen-fixing bacteria (rhizobia) span a continuum of specialization, and promiscuous legumes are thought to have higher chances of forming effective symbioses in novel ranges. Using Australian Acacia species in South Africa, it was hypothesized that widespread and highly invasive species will be more generalist in their rhizobial symbiotic requirements and more effective in fixing atmospheric nitrogen compared with localized and less invasive species. To test these hypotheses, eight localized and 11 widespread acacias were examined using next-generation sequencing data for the nodulation gene, nodC , to compare the identity, species richness, diversity and compositional similarity of rhizobia associated with these acacias. Stable isotope analysis was also used to determine levels of nitrogen obtained from the atmosphere via symbiotic nitrogen fixation. No differences were found in richness, diversity and community composition between localized and widespread acacias. Similarly, widespread and localized acacias did not differ in their ability to fix atmospheric nitrogen. However, for some species by site comparisons, significant differences in δ15N isotopic signatures were found, indicating differential symbiotic effectiveness between these species at specific localities. Overall, the results support recent findings that root nodule rhizobial diversity and community composition do not differ between acacias that vary in their invasiveness. Differential invasiveness of acacias in South Africa is probably linked to attributes such as differences in propagule pressure, reasons for (e.g. forestry vs. ornamental) and extent of, plantings in the country.

  6. By their own devices: invasive Argentine ants have shifted diet without clear aid from symbiotic microbes.

    Science.gov (United States)

    Hu, Yi; Holway, David A; Łukasik, Piotr; Chau, Linh; Kay, Adam D; LeBrun, Edward G; Miller, Katie A; Sanders, Jon G; Suarez, Andrew V; Russell, Jacob A

    2017-03-01

    The functions and compositions of symbiotic bacterial communities often correlate with host ecology. Yet cause-effect relationships and the order of symbiont vs. host change remain unclear in the face of ancient symbioses and conserved host ecology. Several groups of ants exemplify this challenge, as their low-nitrogen diets and specialized symbioses appear conserved and ancient. To address whether nitrogen-provisioning symbionts might be important in the early stages of ant trophic shifts, we studied bacteria from the Argentine ant, Linepithema humile - an invasive species that has transitioned towards greater consumption of sugar-rich, nitrogen-poor foods in parts of its introduced range. Bacteria were present at low densities in most L. humile workers, and among those yielding quality 16S rRNA amplicon sequencing data, we found just three symbionts to be common and dominant. Two, a Lactobacillus and an Acetobacteraceae species, were shared between native and introduced populations. The other, a Rickettsia, was found only in two introduced supercolonies. Across an eight-year period of trophic reduction in one introduced population, we found no change in symbionts, arguing against a relationship between natural dietary change and microbiome composition. Overall, our findings thus argue against major changes in symbiotic bacteria in association with the invasion and trophic shift of L. humile. In addition, genome content from close relatives of the identified symbionts suggests that just one can synthesize most essential amino acids; this bacterium was only modestly abundant in introduced populations, providing little support for a major role of nitrogen-provisioning symbioses in Argentine ant's dietary shift. © 2016 John Wiley & Sons Ltd.

  7. Beneficial bacteria inhibit cachexia

    Science.gov (United States)

    Varian, Bernard J.; Goureshetti, Sravya; Poutahidis, Theofilos; Lakritz, Jessica R.; Levkovich, Tatiana; Kwok, Caitlin; Teliousis, Konstantinos; Ibrahim, Yassin M.; Mirabal, Sheyla; Erdman, Susan E.

    2016-01-01

    Muscle wasting, known as cachexia, is a debilitating condition associated with chronic inflammation such as during cancer. Beneficial microbes have been shown to optimize systemic inflammatory tone during good health; however, interactions between microbes and host immunity in the context of cachexia are incompletely understood. Here we use mouse models to test roles for bacteria in muscle wasting syndromes. We find that feeding of a human commensal microbe, Lactobacillus reuteri, to mice is sufficient to lower systemic indices of inflammation and inhibit cachexia. Further, the microbial muscle-building phenomenon extends to normal aging as wild type animals exhibited increased growth hormone levels and up-regulation of transcription factor Forkhead Box N1 [FoxN1] associated with thymus gland retention and longevity. Interestingly, mice with a defective FoxN1 gene (athymic nude) fail to inhibit sarcopenia after L. reuteri therapy, indicating a FoxN1-mediated mechanism. In conclusion, symbiotic bacteria may serve to stimulate FoxN1 and thymic functions that regulate inflammation, offering possible alternatives for cachexia prevention and novel insights into roles for microbiota in mammalian ontogeny and phylogeny. PMID:26933816

  8. 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.

  9. Toxic effects of arsenic on Sinorhizobium-Medicago sativa symbiotic interaction

    Energy Technology Data Exchange (ETDEWEB)

    Pajuelo, Eloisa [Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville (Spain); Rodriguez-Llorente, Ignacio D. [Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville (Spain)], E-mail: irodri@us.es; Dary, Mohammed; Palomares, Antonio J. [Department of Microbiology and Parasitology, Faculty of Pharmacy, University of Seville, 41012 Seville (Spain)

    2008-07-15

    Recently, the Rhizobium-legume symbiotic interaction has been proposed as an interesting tool in bioremediation. However, little is known about the effect of most common contaminants on this process. The phytotoxic effects of arsenic on nodulation of Medicago sativa have been examined in vitro using the highly arsenic resistant and symbiotically effective Sinorhizobium sp. strain MA11. The bacteria were able to grow on plates containing As concentrations as high as 10 mM. Nevertheless, as little as 25-35 {mu}M arsenite produced a 75% decrease in the total number of nodules, due to a 90% reduction in the number of rhizobial infections, as could be determined using the strain MA11 carrying a lacZ reporter gene. This effect was associated to root hair damage and a shorter infective root zone. However, once nodulation was established nodule development seemed to continue normally, although earlier senescence could be observed in nodules of arsenic-grown plants. - First steps of nodulation of alfalfa, in particular infection thread formation, are more sensitive to As than nitrogen fixation due to plant effects.

  10. Survival of Host-Associated Bacteroidales Cells and Their Relationship with Enterococcus spp., Campylobacter jejuni, Salmonella enterica Serovar Typhimurium, and Adenovirus in Freshwater Microcosms as Measured by Propidium Monoazide-Quantitative PCR

    Science.gov (United States)

    Bae, Sungwoo

    2012-01-01

    The ideal host-associated genetic fecal marker would be capable of predicting the presence of specific pathogens of concern. Flowthrough freshwater microcosms containing mixed feces and inocula of the pathogens Campylobacter jejuni, Salmonella enterica serovar Typhimurium, and adenovirus were placed at ambient temperature in the presence and absence of diurnal sunlight. The total Enterococcus DNA increased during the early periods (23 h) under sunlight exposure, even though cultivable Enterococcus and DNA in intact cells, as measured by propidium monoazide (PMA), decreased with first-order kinetics during the entire period. We found a significant difference in the decay of host-associated Bacteroidales cells between sunlight exposure and dark conditions (P value 0.05). Overall, the ratio of quantitative PCR (qPCR) cycle threshold (CT) values with and without PMA treatment was indicative of the time elapsed since inoculation of the microcosm with (i) fecal material from different animal sources based on host-associated Bacteroidales and (ii) pure cultures of bacterial pathogens. The use of both PMA-qPCR and qPCR may yield more realistic information about recent sources of fecal contamination and result in improved prediction of waterborne pathogens and assessment of health risk. PMID:22139002

  11. Outbursts In Symbiotic Binaries (FUSE 2000)

    Science.gov (United States)

    Kenyon, Scott J.; Sonneborn, George (Technical Monitor)

    2002-01-01

    During the past year, we made good progress on analysis of FUSE observations of the symbiotic binary Z And. For background, Z And is a binary system composed of a red giant and a hot component of unknown status. The orbital period is roughly 750 days. The hot component undergoes large-scale eruptions every 10-20 yr. An outburst began several years ago, triggering this FUSE opportunity. First, we obtained an excellent set of ground-based optical data in support, of the FUSE observations. We used FAST, a high throughput low resolution spectrograph on the 1.5-m telescope at Mt. Hopkins, Arizona. A 300 g/ mm grating blazed at 4750 A, a 3 in. slit, and a thinned Loral 512 x 2688 CCD gave us spectra covering 3800-7500 A at a resolution of 6 A. The wavelength solution for each spectrum has a probable error of +/- 0.5 A or better. Most of the resulting spectra have moderate signal-to-noise, S/.N approx. greater than 30 per pixel. The time coverage for these spectra is excellent. Typically, we acquired spectra every 1-2 nights during dark runs at Mt. Hopkins. These data cover most of the rise and all of the decline of the recent outburst. The spectra show a wealth of emission lines, including H I, He I, He II, [Fe V11], and the Raman scattering bands at 6830 A and 7088 A. The Raman bands and other high ionization features vary considerably throughout the outburst. These features will enable us to correlate variations in the FUSE spectra with variations in the optical spectra. Second, we began an analysis of FUSE spectra of Z And. We have carefully examined the spectra, identifying real features and defects. We have identified and measured fluxes for all strong emission lines, including the O VI doublet at 1032 A and 1038 A. These and several other strong emission lines display pronounced P Cygni absorption components indicative of outgrowing gas. We will attempt to correlate these velocities with similar profiles observed on optical spectra. The line velocities - together

  12. Comprehensive EST analysis of the symbiotic sea anemone, Anemonia viridis

    Directory of Open Access Journals (Sweden)

    Deleury Emeline

    2009-07-01

    Full Text Available Abstract Background Coral reef ecosystems are renowned for their diversity and beauty. Their immense ecological success is due to a symbiotic association between cnidarian hosts and unicellular dinoflagellate algae, known as zooxanthellae. These algae are photosynthetic and the cnidarian-zooxanthellae association is based on nutritional exchanges. Maintenance of such an intimate cellular partnership involves many crosstalks between the partners. To better characterize symbiotic relationships between a cnidarian host and its dinoflagellate symbionts, we conducted a large-scale EST study on a symbiotic sea anemone, Anemonia viridis, in which the two tissue layers (epiderm and gastroderm can be easily separated. Results A single cDNA library was constructed from symbiotic tissue of sea anemones A. viridis in various environmental conditions (both normal and stressed. We generated 39,939 high quality ESTs, which were assembled into 14,504 unique sequences (UniSeqs. Sequences were analysed and sorted according to their putative origin (animal, algal or bacterial. We identified many new repeated elements in the 3'UTR of most animal genes, suggesting that these elements potentially have a biological role, especially with respect to gene expression regulation. We identified genes of animal origin that have no homolog in the non-symbiotic starlet sea anemone Nematostella vectensis genome, but in other symbiotic cnidarians, and may therefore be involved in the symbiosis relationship in A. viridis. Comparison of protein domain occurrence in A. viridis with that in N. vectensis demonstrated an increase in abundance of some molecular functions, such as protein binding or antioxidant activity, suggesting that these functions are essential for the symbiotic state and may be specific adaptations. Conclusion This large dataset of sequences provides a valuable resource for future studies on symbiotic interactions in Cnidaria. The comparison with the closest

  13. Symbiotic in vitro seed propagation of Dendrobium: fungal and bacterial partners and their influence on plant growth and development.

    Science.gov (United States)

    Teixeira da Silva, Jaime A; Tsavkelova, Elena A; Zeng, Songjun; Ng, Tzi Bun; Parthibhan, S; Dobránszki, Judit; Cardoso, Jean Carlos; Rao, M V

    2015-07-01

    The genus Dendrobium is one of the largest genera of the Orchidaceae Juss. family, although some of its members are the most threatened today. The reason why many species face a vulnerable or endangered status is primarily because of anthropogenic interference in natural habitats and commercial overexploitation. The development and application of modern techniques and strategies directed towards in vitro propagation of orchids not only increases their number but also provides a viable means to conserve plants in an artificial environment, both in vitro and ex vitro, thus providing material for reintroduction. Dendrobium seed germination and propagation are challenging processes in vivo and in vitro, especially when the extreme specialization of these plants is considered: (1) their biotic relationships with pollinators and mycorrhizae; (2) adaptation to epiphytic or lithophytic life-styles; (3) fine-scale requirements for an optimal combination of nutrients, light, temperature, and pH. This review also aims to summarize the available data on symbiotic in vitro Dendrobium seed germination. The influence of abiotic factors as well as composition and amounts of different exogenous nutrient substances is examined. With a view to better understanding how to optimize and control in vitro symbiotic associations, a part of the review describes the strong biotic relations of Dendrobium with different associative microorganisms that form microbial communities with adult plants, and also influence symbiotic seed germination. The beneficial role of plant growth-promoting bacteria is also discussed.

  14. Characterization of a Symbiotic Coculture of Clostridium thermohydrosulfuricum YM3 and Clostridium thermocellum YM4.

    Science.gov (United States)

    Mori, Y

    1990-01-01

    Clostridium thermohydrosulfuricum YM3 and C. thermocellum YM4 were isolated from a coculture which was obtained from an enrichment culture inoculated with volcanic soil in Izu Peninsula, Japan. Strain YM3 had advantages over reported C. thermohydrosulfuricum strains in that it fermented inulin and could accumulate ethanol up to 1.3% (wt/vol). The highest ethanol yield obtained was 1.96 mol/mol of anhydroglucose unit in cellobiose. Strain YM4 had features different from those reported in C. thermocellum strains: it formed spores rarely (at a frequency of microorganism was able to grow. However, the coculture grew on cellulose without yeast extract and produced ethanol in high yield. Moreover, cell-free spent culture broth of strain YM3 could replace yeast extract in supporting the growth of strain YM4. The symbiotic relationship of the two bacteria in cellulose fermentation is probably a case of mutualism.

  15. Cues from the reef: olfactory preferences of a symbiotically luminous cardinalfish

    Science.gov (United States)

    Gould, Alison L.; Harii, Saki; Dunlap, Paul V.

    2015-06-01

    The symbiotically luminous, reef-dwelling cardinalfish, Siphamia tubifer (Perciformes: Apogonidae), exhibits daily site fidelity, homing behavior, and a preference for the long-spined urchin, Diadema setosum, as its daytime host. The fish acquires its symbiont during larval development and releases large numbers of the bacteria with its feces daily at a host urchin. To examine the role of olfaction in site fidelity and homing by S. tubifer, juvenile and adult fish were tested in a two-channel choice flume for their olfactory preferences. Neither juveniles nor adults showed a preference for seawater conditioned by D. setosum. Juvenile fish, but not adults, preferred seawater conditioned by conspecific fish versus unconditioned seawater. Both juveniles and adults preferred seawater conditioned by their luminous symbiont and also preferred home site water to foreign reef water. These results suggest that S. tubifer uses chemical cues for homing and possibly settlement and symbiont acquisition, but not for host urchin recognition.

  16. The Sinorhizobium meliloti RNA chaperone Hfq influences central carbon metabolism and the symbiotic interaction with alfalfa

    Directory of Open Access Journals (Sweden)

    Jiménez-Zurdo José I

    2010-03-01

    Full Text Available Abstract Background The bacterial Hfq protein is able to interact with diverse RNA molecules, including regulatory small non-coding RNAs (sRNAs, and thus it is recognized as a global post-transcriptional regulator of gene expression. Loss of Hfq has an extensive impact in bacterial physiology which in several animal pathogens influences virulence. Sinorhizobium meliloti is a model soil bacterium known for its ability to establish a beneficial nitrogen-fixing intracellular symbiosis with alfalfa. Despite the predicted general involvement of Hfq in the establishment of successful bacteria-eukaryote interactions, its function in S. meliloti has remained unexplored. Results Two independent S. meliloti mutants, 2011-3.4 and 1021Δhfq, were obtained by disruption and deletion of the hfq gene in the wild-type strains 2011 and 1021, respectively, both exhibiting similar growth defects as free-living bacteria. Transcriptomic profiling of 1021Δhfq revealed a general down-regulation of genes of sugar transporters and some enzymes of the central carbon metabolism, whereas transcripts specifying the uptake and metabolism of nitrogen sources (mainly amino acids were more abundant than in the wild-type strain. Proteomic analysis of the 2011-3.4 mutant independently confirmed these observations. Symbiotic tests showed that lack of Hfq led to a delayed nodulation, severely compromised bacterial competitiveness on alfalfa roots and impaired normal plant growth. Furthermore, a large proportion of nodules (55%-64% elicited by the 1021Δhfq mutant were non-fixing, with scarce content in bacteroids and signs of premature senescence of endosymbiotic bacteria. RT-PCR experiments on RNA from bacteria grown under aerobic and microoxic conditions revealed that Hfq contributes to regulation of nifA and fixK1/K2, the genes controlling nitrogen fixation, although the Hfq-mediated regulation of fixK is only aerobiosis dependent. Finally, we found that some of the recently

  17. Molecular adaptation in flowering and symbiotic recognition pathways: insights from patterns of polymorphism in the legume Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Ronfort Joëlle

    2011-08-01

    Full Text Available Abstract Background We studied patterns of molecular adaptation in the wild Mediterranean legume Medicago truncatula. We focused on two phenotypic traits that are not functionally linked: flowering time and perception of symbiotic microbes. Phenology is an important fitness component, especially for annual plants, and many instances of molecular adaptation have been reported for genes involved in flowering pathways. While perception of symbiotic microbes is also integral to adaptation in many plant species, very few reports of molecular adaptation exist for symbiotic genes. Here we used data from 57 individuals and 53 gene fragments to quantify the overall strength of both positive and purifying selection in M. truncatula and asked if footprints of positive selection can be detected at key genes of rhizobia recognition pathways. Results We examined nucleotide variation among 57 accessions from natural populations in 53 gene fragments: 5 genes involved in nitrogen-fixing bacteria recognition, 11 genes involved in flowering, and 37 genes used as control loci. We detected 1757 polymorphic sites yielding an average nucleotide diversity (pi of 0.003 per site. Non-synonymous variation is under sizable purifying selection with 90% of amino-acid changing mutations being strongly selected against. Accessions were structured in two groups consistent with geographical origins. Each of these two groups harboured an excess of rare alleles, relative to expectations of a constant-sized population, suggesting recent population expansion. Using coalescent simulations and an approximate Bayesian computation framework we detected several instances of genes departing from selective neutrality within each group and showed that the polymorphism of two nodulation and four flowering genes has probably been shaped by recent positive selection. Conclusion We quantify the intensity of purifying selection in the M. truncatula genome and show that putative footprints of

  18. Non-symbiotic hemoglobin and its relation with hypoxic stress

    Directory of Open Access Journals (Sweden)

    Alejandro Riquelme

    2015-08-01

    Full Text Available Today we know that several types of hemoglobins exist in plants. The symbiotic hemoglobins were discovered in 1939 and are only found in nodules of plants capable of symbiotically fixing atmospheric N. Another class, called non-symbiotic hemoglobin, was discovered 32 yr ago and is now thought to exist throughout the plant kingdom, being expressed in different organs and tissues. Recently the existence of another type of hemoglobin, called truncated hemoglobin, was demonstrated in plants. Although the presence of hemoglobins is widespread in the plant kingdom, their role has not yet been fully elucidated. This review discusses recent findings regarding the role of plant hemoglobins, with special emphasis on their relationship to plants adaptation to hypoxia. It also discusses the role of nitric oxide in plant cells under hypoxic conditions, since one of the functions of hemoglobin appears to be modulating nitric oxide levels in the cells.

  19. Symbiotic fungal associations in 'lower' land plants.

    Science.gov (United States)

    Read, D J; Ducket, J G; Francis, R; Ligron, R; Russell, A

    2000-06-29

    An analysis of the current state of knowledge of symbiotic fungal associations in 'lower' plants is provided. Three fungal phyla, the Zygomycota, Ascomycota and Basidiomycota, are involved in forming these associations, each producing a distinctive suite of structural features in well-defined groups of 'lower' plants. Among the 'lower' plants only mosses and Equisetum appear to lack one or other of these types of association. The salient features of the symbioses produced by each fungal group are described and the relationships between these associations and those formed by the same or related fungi in 'higher' plants are discussed. Particular consideration is given to the question of the extent to which root fungus associations in 'lower' plants are analogous to 'mycorrhizas' of 'higher' plants and the need for analysis of the functional attributes of these symbioses is stressed. Zygomycetous fungi colonize a wide range of extant lower land plants (hornworts, many hepatics, lycopods, Ophioglossales, Psilotales and Gleicheniaceae), where they often produce structures analogous to those seen in the vesicular-arbuscular (VA) mycorrhizas of higher plants, which are formed by members of the order Glomales. A preponderance of associations of this kind is in accordance with palaeohbotanical and molecular evidence indicating that glomalean fungi produced the archetypal symbioses with the first plants to emerge on to land. It is shown, probably for the first time, that glomalean fungi forming typical VA mycorrhiza with a higher plant (Plantago lanceolata) can colonize a thalloid liverwort (Pellia epiphylla), producing arbuscules and vesicles in the hepatic. The extent to which these associations, which are structurally analogous to mycorrhizas, have similar functions remains to be evaluated. Ascomycetous associations are found in a relatively small number of families of leafy liverworts. The structural features of the fungal colonization of rhizoids and underground axes of

  20. Genomic analysis reveals versatile heterotrophic capacity of a potentially symbiotic sulfur-oxidizing bacterium in sponge

    KAUST Repository

    Tian, Renmao

    2014-08-29

    Sulfur-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) play essential roles in marine sponges. However, the detailed characteristics and physiology of the bacteria are largely unknown. Here, we present and analyse the first genome of sponge-associated SOB using a recently developed metagenomic binning strategy. The loss of transposase and virulence-associated genes and the maintenance of the ancient polyphosphate glucokinase gene suggested a stabilized SOB genome that might have coevolved with the ancient host during establishment of their association. Exclusive distribution in sponge, bacterial detoxification for the host (sulfide oxidation) and the enrichment for symbiotic characteristics (genes-encoding ankyrin) in the SOB genome supported the bacterial role as an intercellular symbiont. Despite possessing complete autotrophic sulfur oxidation pathways, the bacterium developed a much more versatile capacity for carbohydrate uptake and metabolism, in comparison with its closest relatives (Thioalkalivibrio) and to other representative autotrophs from the same order (Chromatiales). The ability to perform both autotrophic and heterotrophic metabolism likely results from the unstable supply of reduced sulfur in the sponge and is considered critical for the sponge-SOB consortium. Our study provides insights into SOB of sponge-specific clade with thioautotrophic and versatile heterotrophic metabolism relevant to its roles in the micro-environment of the sponge body. © 2014 Society for Applied Microbiology and John Wiley & Sons Ltd.

  1. Effect of Subliminal Stimulation of Symbiotic Fantasies on Behavior Modification Treatment of Obesity.

    Science.gov (United States)

    And Others; Silverman, Lloyd H.

    1978-01-01

    Obese women were treated in behavior modification programs for overeating. Behavior programs were accompanied by subliminal stimulation and by symbiotic and control messages. The symbiotic condition gave evidence of enhancing weight loss. This finding supports the proposition that subliminal stimulation of symbiotic fantasies can enhance the…

  2. SYMBIOTIC STAR BLOWS BUBBLES INTO SPACE

    Science.gov (United States)

    2002-01-01

    A tempestuous relationship between an unlikely pair of stars may have created an oddly shaped, gaseous nebula that resembles an hourglass nestled within an hourglass. Images taken with Earth-based telescopes have shown the larger, hourglass-shaped nebula. But this picture, taken with NASA's Hubble Space Telescope, reveals a small, bright nebula embedded in the center of the larger one (close-up of nebula in inset). Astronomers have dubbed the entire nebula the 'Southern Crab Nebula' (He2-104), because, from ground-based telescopes, it looks like the body and legs of a crab. The nebula is several light-years long. The possible creators of these shapes cannot be seen at all in this Wide Field and Planetary Camera 2 image. It's a pair of aging stars buried in the glow of the tiny, central nebula. One of them is a red giant, a bloated star that is exhausting its nuclear fuel and is shedding its outer layers in a powerful stellar wind. Its companion is a hot, white dwarf, a stellar zombie of a burned-out star. This odd duo of a red giant and a white dwarf is called a symbiotic system. The red giant is also a Mira Variable, a pulsating red giant, that is far away from its partner. It could take as much as 100 years for the two to orbit around each other. Astronomers speculate that the interaction between these two stars may have sparked episodic outbursts of material, creating the gaseous bubbles that form the nebula. They interact by playing a celestial game of 'catch': as the red giant throws off its bulk in a powerful stellar wind, the white dwarf catches some of it. As a result, an accretion disk of material forms around the white dwarf and spirals onto its hot surface. Gas continues to build up on the surface until it sparks an eruption, blowing material into space. This explosive event may have happened twice in the 'Southern Crab.' Astronomers speculate that the hourglass-shaped nebulae represent two separate outbursts that occurred several thousand years apart

  3. Rare Freshwater Ciliate Paramecium chlorelligerum Kahl, 1935 and Its Macronuclear Symbiotic Bacterium “Candidatus Holospora parva”

    Science.gov (United States)

    Lebedeva, Natalia; Migunova, Alexandra; Petroni, Giulio

    2016-01-01

    Ciliated protists often form symbioses with many diverse microorganisms. In particular, symbiotic associations between ciliates and green algae, as well as between ciliates and intracellular bacteria, are rather wide-spread in nature. In this study, we describe the complex symbiotic system between a very rare ciliate, Paramecium chlorelligerum, unicellular algae inhabiting its cytoplasm, and novel bacteria colonizing the host macronucleus. Paramecium chlorelligerum, previously found only twice in Germany, was retrieved from a novel location in vicinity of St. Petersburg in Russia. Species identification was based on both classical morphological methods and analysis of the small subunit rDNA. Numerous algae occupying the cytoplasm of this ciliate were identified with ultrastructural and molecular methods as representatives of the Meyerella genus, which before was not considered among symbiotic algae. In the same locality at least fifteen other species of “green” ciliates were found, thus it is indeed a biodiversity hot-spot for such protists. A novel species of bacterial symbionts living in the macronucleus of Paramecium chlorelligerum cells was morphologically and ultrastructurally investigated in detail with the description of its life cycle and infection capabilities. The new endosymbiont was molecularly characterized following the full-cycle rRNA approach. Furthermore, phylogenetic analysis confirmed that the novel bacterium is a member of Holospora genus branching basally but sharing all characteristics of the genus except inducing connecting piece formation during the infected host nucleus division. We propose the name “Candidatus Holospora parva” for this newly described species. The described complex system raises new questions on how these microorganisms evolve and interact in symbiosis. PMID:27992463

  4. Interacting Winds in Eclipsing Symbiotic Systems – The Case Study ...

    Indian Academy of Sciences (India)

    The most adopted physical modeling for many symbiotic stars is that of interacting binaries: a cool giant, a hot .... envelopes the area behind the hot component; and if mw > 1, the hot wind predom- inates the cool wind. ...... Tomov, N., Tomova, M. 2001, Astrophysics and Space Science, 278, 311. Torbett, M. V., Campbell, B.

  5. Diversity of the Symbiotic Alga Symbiodinium in Tanzanian ...

    African Journals Online (AJOL)

    Abstract—With the current increase in frequency of coral bleaching events, knowledge on the genetic diversity of symbiotic algae in the genus Symbiodinium harboured by reef-building corals is important to understand how coral reefs will respond to global climate change. This study was undertaken as very little is known.

  6. Survivability of probiotics in symbiotic low fat buffalo milk yogurt ...

    African Journals Online (AJOL)

    In present study, symbiotic low fat buffalo milk yogurt prototypes (plain and blueberry) were developed using a commercial starter containing probiotics. Samples were analyzed for physicochemical and microbiological properties, and the survivability of probiotics during 10 weeks of storage. Gross composition results were: ...

  7. Interacting Winds in Eclipsing Symbiotic Systems–The Case Study ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We report the mathematical representation of the so called eccentric eclipse model, whose numerical solutions can be used to obtain the physical parameters of a quiescent eclipsing symbiotic system. Indeed the nebular region produced by the collision of the stellar winds should be shifted to the orbital ...

  8. Symbiotic Blue Green Algae (Azolla): A Potential Bio fertilizer for ...

    African Journals Online (AJOL)

    Symbiotic Blue Green Algae (Azolla): A Potential Bio fertilizer for Paddy Rice Production in Fogera Plain, Northwestern Ethiopia. ... They were maintained and multiplied in plastic containers at Adet in a greenhouse and then inoculated into concrete tanks for testing their adaptability. Both strains were well adapted to Adet ...

  9. Competitive interactions among symbiotic fungi of the southern pine beetle

    Science.gov (United States)

    Kier D. Klepzig; Richard T. Wilkens

    1997-01-01

    The southern pine beetle, a damaging pest of conifers, is intimately linked to three symbiotic fungi.Two fungi, Ceratocystiopsis ranaculosus and Entomocorticium sp. A, are transported within specialized structures (mycangia) in the beetle exoskeleton and are mutualists of the beetle.A third fungus, Ophiostoma minus, is transported externally on the beetle exoskeleton (...

  10. Symbiotic effectiveness of pea-rhizobia associations and the ...

    African Journals Online (AJOL)

    微软用户

    2011-05-02

    May 2, 2011 ... Interactions between pea (Pisum sativa L.) cultivars and Rhizobium strain affect the symbiotic relationship and ultimately both the nitrogen fixing capacity and the yield. Since Pisum sativum L. is poorly nodulated in the Loess Plateau of China where this crop is grown, the response of pea cultivars. Yannong ...

  11. Binding Cultures: A Symbiotic Vision of Francis Bebey in Agatha ...

    African Journals Online (AJOL)

    Binding Cultures: A Symbiotic Vision of Francis Bebey in Agatha Moudio's Son. Kelvin Ngong Toh. Abstract. No Abstract. LWATI: A Journal of Contemporary Research, 9(3), 126-135, 2012. Full Text: EMAIL FULL TEXT EMAIL FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · AJOL African Journals Online.

  12. Role of symbiotic nitrogen fixation in the improvement of legume ...

    African Journals Online (AJOL)

    Role of symbiotic nitrogen fixation in the improvement of legume productivity under stressed environments. R Serraj, J Adu-Gyamfi. Abstract. No Abstract. Full Text: EMAIL FREE FULL TEXT EMAIL FREE FULL TEXT · DOWNLOAD FULL TEXT DOWNLOAD FULL TEXT · http://dx.doi.org/10.4314/wajae.v6i1.45613.

  13. Optical flickering of the symbiotic star CH Cyg

    Science.gov (United States)

    Stoyanov, K. A.; Martí, J.; Zamanov, R.; Dimitrov, V. V.; Kurtenkov, A.; Sánchez-Ayaso, E.; Bujalance-Fernández, I.; Latev, G. Y.; Nikolov, G.

    2018-02-01

    Here we present quasi-simultaneous observations of the flickering of the symbiotic binary star CH Cyg in U, B and V bands. We calculate the flickering source parameters and discuss the possible reason for the flickering cessation in the period 2010-2013.

  14. The symbiotic intestinal ciliates and the evolution of their hosts

    NARCIS (Netherlands)

    Moon-van der Staay, S.Y.; Staay, G.W. van der; Michalowski, T.; Jouany, J.P.; Pristas, P.; Javorsky, P.; Kisidayova, S.; Varadyova, Z.; McEwan, N.R.; Newbold, C.J.; Alen, T. van; Graaf, R. de; Schmid, M.; Huynen, M.A.; Hackstein, J.H.

    2014-01-01

    The evolution of sophisticated differentiations of the gastro-intestinal tract enabled herbivorous mammals to digest dietary cellulose and hemicellulose with the aid of a complex anaerobic microbiota. Distinctive symbiotic ciliates, which are unique to this habitat, are the largest representatives

  15. Biodiversity and studies of marine symbiotic siphonostomatoids off ...

    African Journals Online (AJOL)

    Current knowledge of the biodiversity of the symbiotic marine siphonostomatoids from South African waters (136 species) is sparse compared to that globally (1 388 species). The difference is especially apparent when taking into account the diversity of fish (more than 2 000 species) and invertebrates (approximately 12 ...

  16. A symbiotic shell-encrusting bryozoan provides subtidal whelks with ...

    African Journals Online (AJOL)

    The subtidal whelk Burnupena papyracea co-occurs with a voracious predator, the rock lobster Jasus lalandii, in situations where other potential prey are largely eliminated. The survival of B. papyracea has been ascribed to a symbiotic bryozoan, Alcyonidium nodosum, which characteristically encrusts the shells of this ...

  17. Genomic and evolutionary comparisons of diazotrophic and pathogenic bacteria of the order Rhizobiales

    Directory of Open Access Journals (Sweden)

    Vasconcelos Ana

    2010-02-01

    Full Text Available Abstract Background Species belonging to the Rhizobiales are intriguing and extensively researched for including both bacteria with the ability to fix nitrogen when in symbiosis with leguminous plants and pathogenic bacteria to animals and plants. Similarities between the strategies adopted by pathogenic and symbiotic Rhizobiales have been described, as well as high variability related to events of horizontal gene transfer. Although it is well known that chromosomal rearrangements, mutations and horizontal gene transfer influence the dynamics of bacterial genomes, in Rhizobiales, the scenario that determine pathogenic or symbiotic lifestyle are not clear and there are very few studies of comparative genomic between these classes of prokaryotic microorganisms trying to delineate the evolutionary characterization of symbiosis and pathogenesis. Results Non-symbiotic nitrogen-fixing bacteria and bacteria involved in bioremediation closer to symbionts and pathogens in study may assist in the origin and ancestry genes and the gene flow occurring in Rhizobiales. The genomic comparisons of 19 species of Rhizobiales, including nitrogen-fixing, bioremediators and pathogens resulted in 33 common clusters to biological nitrogen fixation and pathogenesis, 15 clusters exclusive to all nitrogen-fixing bacteria and bacteria involved in bioremediation, 13 clusters found in only some nitrogen-fixing and bioremediation bacteria, 01 cluster exclusive to some symbionts, and 01 cluster found only in some pathogens analyzed. In BBH performed to all strains studied, 77 common genes were obtained, 17 of which were related to biological nitrogen fixation and pathogenesis. Phylogenetic reconstructions for Fix, Nif, Nod, Vir, and Trb showed possible horizontal gene transfer events, grouping species of different phenotypes. Conclusions The presence of symbiotic and virulence genes in both pathogens and symbionts does not seem to be the only determinant factor for lifestyle

  18. Molecular and biochemical analysis of symbiotic plant receptor kinase complexes

    Energy Technology Data Exchange (ETDEWEB)

    Cook, Douglas R; Riely, Brendan K

    2010-09-01

    DE-FG02-01ER15200 was a 36-month project, initiated on Sept 1, 2005 and extended with a one-year no cost extension to August 31, 2009. During the project period we published seven manuscripts (2 in review). Including the prior project period (2002-2005) we published 12 manuscripts in journals that include Science, PNAS, The Plant Cell, Plant Journal, Plant Physiology, and MPMI. The primary focus of this work was to further elucidate the function of the Nod factor signaling pathway that is involved in initiation of the legume-rhizobium symbiosis and in particular to explore the relationship between receptor kinase-like proteins and downstream effectors of symbiotic development. During the project period we have map-base cloned two additional players in symbiotic development, including an ERF transcription factor and an ethylene pathway gene (EIN2) that negatively regulates symbiotic signaling; we have also further characterized the subcellular distribution and function of a nuclear-localized symbiosis-specific ion channel, DMI1. The major outcome of the work has been the development of systems for exploring and validating protein-protein interactions that connect symbiotic receptor-like proteins to downstream responses. In this regard, we have developed both homologous (i.e., in planta) and heterologous (i.e., in yeast) systems to test protein interactions. Using yeast 2-hybrid screens we isolated the only known interactor of the nuclear-localized calcium-responsive kinase DMI3. We have also used yeast 2-hybrid methodology to identify interactions between symbiotic signaling proteins and certain RopGTPase/RopGEF proteins that regulate root hair polar growth. More important to the long-term goals of our work, we have established a TAP tagging system that identifies in planta interactions based on co-immuno precipitation and mass spectrometry. The validity of this approach has been shown using known interactors that either co-iummnoprecipate (i.e., remorin) or co

  19. Lack of endosymbiont release by two Lucinidae (Bivalvia) of the genus Codakia: consequences for symbiotic relationships.

    Science.gov (United States)

    Brissac, Terry; Gros, Olivier; Merçot, Hervé

    2009-02-01

    Associations between marine invertebrates and chemoautotrophic bacteria constitute a wide field for the study of symbiotic associations. In these interactions, symbiont transmission must represent the cornerstone allowing the persistence of the association throughout generations. Within Bivalvia, in families such as Solemyidae or Vesicomyidae, symbiont transmission is undoubtedly vertical. However, in Lucinidae, symbiont transmission is described in the literature as 'environmental', symbionts being acquired from the environment by the new host generations. Hence, if there is transmission, symbionts should be transmitted from adults to juveniles via the environment. Consequently, we should observe a release of the symbiont by adults. We attempted to detect such a release within two Lucinidae species of the genus Codakia. We sampled 10 Codakia orbicularis and 20 Codakia orbiculata distributed in 10 crystallizing dishes containing filtered seawater. During 1 month of investigation, we analyzed water of the dishes in order to detect any release of a symbiont using catalyzed report deposition-FISH techniques. For 140 observations realized during this period, we did not observe any release of symbionts. This suggests that the idea of host-to-host passage in Lucinidae is inaccurate. We could therefore consider that the transmission mode from generation to generation does not occur within Lucinidae, symbiosis appearing to be advantageous in this case only for the host, and constitutes an evolutionary dead-end for the bacteria.

  20. Genomes of three facultatively symbiotic Frankia sp. strainsreflect host plant biogeography

    Energy Technology Data Exchange (ETDEWEB)

    Normand, Philippe; Lapierre, Pascal; Tisa, Louis S.; Gogarten, J.Peter; Alloisio, Nicole; Bagnarol, Emilie; Bassi, Carla A.; Berry,Alison; Bickhart, Derek M.; Choisne, Nathalie; Couloux, Arnaud; Cournoyer, Benoit; Cruveiller, Stephane; Daubin, Vincent; Demange, Nadia; Francino, M. Pilar; Ggoltsman, Eugene; Huang, Ying; Kopp, Olga; Labarre,Laurent; Lapidus, Alla; Lavire, Celine; Marechal, Joelle; Martinez,Michele; Mastronunzio, Juliana E.; Mullin, Beth; Niemann, James; Pujic,Pierre; Rawnsley, Tania; Rouy, Zoe; Schenowitz, Chantal; Sellstedt,Anita; Tavares, Fernando; Tomkins, Jeffrey P.; Vallenet, David; Valverde,Claudio; Wall, Luis; Wang, Ying; Medigue, Claudine; Benson, David R.

    2006-02-01

    Filamentous actinobacteria from the genus Frankia anddiverse woody trees and shrubs together form N2-fixing actinorhizal rootnodule symbioses that are a major source of new soil nitrogen in widelydiverse biomes 1. Three major clades of Frankia sp. strains are defined;each clade is associated with a defined subset of plants from among theeight actinorhizal plant families 2,3. The evolution arytrajectoriesfollowed by the ancestors of both symbionts leading to current patternsof symbiont compatibility are unknown. Here we show that the competingprocesses of genome expansion and contraction have operated in differentgroups of Frankia strains in a manner that can be related to thespeciation of the plant hosts and their geographic distribution. Wesequenced and compared the genomes from three Frankia sp. strains havingdifferent host plant specificities. The sizes of their genomes variedfrom 5.38 Mbp for a narrow host range strain (HFPCcI3) to 7.50Mbp for amedium host range strain (ACN14a) to 9.08 Mbp for a broad host rangestrain (EAN1pec.) This size divergence is the largest yet reported forsuch closely related bacteria. Since the order of divergence of thestrains is known, the extent of gene deletion, duplication andacquisition could be estimated and was found to be inconcert with thebiogeographic history of the symbioses. Host plant isolation favoredgenome contraction, whereas host plant diversification favored genomeexpansion. The results support the idea that major genome reductions aswell as expansions can occur in facultatively symbiotic soil bacteria asthey respond to new environments in the context of theirsymbioses.

  1. Potential use of rhizobial bacteria as promoters of plant growth for ...

    African Journals Online (AJOL)

    Rhizobia form root nodules that fix nitrogen (N2) in symbiotic legumes. Extending the ability of these bacteria to fix N2 in non-legumes such as cereals would be a useful technology for increased crop yields among resource-poor farmers. Although some inoculation attempts have resulted in nodule formation in cereal plants, ...

  2. Relative symbiont input and the lichen symbiotic outcome.

    Science.gov (United States)

    Spribille, Toby

    2018-03-09

    The term symbiosis was first used in biology to describe the 'living together' of fungi and algae in lichens. For much of the 20th century, the fungal partner was assumed to be invested with the ability to produce the lichen body plan in presence of a photosynthesizing partner. However, studies of fungal evolution have uncovered discordance between lichen symbiotic outcomes and genome evolution of the fungus. At the same time, evidence has emerged that the structurally important lichen cortex contains lichen-specific, single-celled microbes, suggesting it may function like a biofilm. Together, these observations suggest we may not have a complete overview of symbiotic interactions in lichens. Understanding phenotype development and evolution in lichens will require greater insight into fungal-fungal and fungal-bacterial interplay and the physical properties of the cortex. Copyright © 2018 Elsevier Ltd. All rights reserved.

  3. Symbiotic properties of Bradyrhizobium sp. (Lupinus assayed on serradella plants

    Directory of Open Access Journals (Sweden)

    Mieczysława Deryło

    2014-01-01

    Full Text Available Physiological and symbiotic properties of Bradyrhizobium sp. (Lupinus nodule isolates were compared to the standard slow-growing Bradyrhizobium sp. (Lupinus strain USDA 3045. Lupine nodules isolates showed typical characteristics for bradyrhizobial strains and nodulated small seed legume, serradella (Ornithopus sativus, in tube test. We observed a permanent physiological segregation of the effective (Fix' and ineffective (Fix- symbiotic phenotype for all tested bradyrhizobial strains during the growth of serradella in plant tube test. The ultrastructural differences between Fix* and Fix serradella nodules were observed. Rapid and visible nodulation as well as easy assay of the reduction of acetylene make serradella a convenient system for studies of Bradyrhizobium sp. (Lupinus strains in laboratory conditions.

  4. Flickering of the symbiotic variable CH Cygni during outburst

    International Nuclear Information System (INIS)

    Slovak, M.H.; Africano, J.

    1978-01-01

    High-speed and conventional BVRI photometry are reported for the bright symbiotic variable CH Cygni (M6 IIIe), obtained during the course of a recent outburst. Unlike the quiescent symbiotic stars, the presence of flickering similar in nature to that seen in the cataclysmic variables has been confirmed during this active phase. The BVRI photometry for a sample of stars in the field is used to derive the reddening and the distance to CH Cyg. A composite energy distribution is derived from 0.35 to 11.0 μm which clearly establishes the existence of a variable, blue continuum. The lack of variability in the near infrared suggests that the blue continuum arises from a hot companion. A binary model including a subluminous hot companion accreting material from the stellar wind of an SRa variable is discussed to account for the observed photometric properties. (author)

  5. Discovery of optical flickering from the symbiotic star EF Aquilae

    Science.gov (United States)

    Zamanov, R. K.; Boeva, S.; Nikolov, Y. M.; Petrov, B.; Bachev, R.; Latev, G. Y.; Popov, V. A.; Stoyanov, K. A.; Bode, M. F.; Martí, J.; Tomov, T.; Antonova, A.

    2017-07-01

    We report optical CCD photometry of the recently identified symbiotic star EF Aql. Our observations in Johnson V and B bands clearly show the presence of stochastic light variations with an amplitude of about 0.2 mag on a time scale of minutes. The observations point toward a white dwarf (WD) as the hot component in the system. It is the 11-th object among more than 200 symbiotic stars known with detected optical flickering. Estimates of the mass accretion rate onto the WD and the mass loss rate in the wind of the Mira secondary star lead to the conclusion that less than 1 per cent of the wind is captured by the WD. Eight further candidates for the detection of flickering in similar systems are suggested.

  6. Symbiotic N fixation of several soybean varieties and mutants

    International Nuclear Information System (INIS)

    Gandanegara, S.; Hendratno, K.

    1988-01-01

    Symbiotic N fixation of several soybean varieties and mutants. Research activities comprising of three experiments were carried out to screen several soybean varieties and mutants for symbiotic N fixation potential. Depending on the medium used, plant response to strains was different. In sterile medium, Rhizobium strain USDA 136, 142 and TAL 102 showed a high nitrogen potential. In soil only Rhizobium strain USDA 110 had better performance and proved to be competitive to the native strains. Nitrogen-15 dilution method was used to screen nitrogen fixing ability of several soybean varieties and mutants. Guntur variety showed a better response to high dose of N fertilizer without disturbance in its fixing ability. This variety then was considered good to be introduced in the cropping system. (author). 8 refs

  7. Training Feedforward Neural Networks Using Symbiotic Organisms Search Algorithm.

    Science.gov (United States)

    Wu, Haizhou; Zhou, Yongquan; Luo, Qifang; Basset, Mohamed Abdel

    2016-01-01

    Symbiotic organisms search (SOS) is a new robust and powerful metaheuristic algorithm, which stimulates the symbiotic interaction strategies adopted by organisms to survive and propagate in the ecosystem. In the supervised learning area, it is a challenging task to present a satisfactory and efficient training algorithm for feedforward neural networks (FNNs). In this paper, SOS is employed as a new method for training FNNs. To investigate the performance of the aforementioned method, eight different datasets selected from the UCI machine learning repository are employed for experiment and the results are compared among seven metaheuristic algorithms. The results show that SOS performs better than other algorithms for training FNNs in terms of converging speed. It is also proven that an FNN trained by the method of SOS has better accuracy than most algorithms compared.

  8. Nutrient acquisition by symbiotic fungi governs Palaeozoic climate transition.

    Science.gov (United States)

    Mills, Benjamin J W; Batterman, Sarah A; Field, Katie J

    2018-02-05

    Fossil evidence from the Rhynie chert indicates that early land plants, which evolved in a high-CO 2 atmosphere during the Palaeozoic Era, hosted diverse fungal symbionts. It is hypothesized that the rise of early non-vascular land plants, and the later evolution of roots and vasculature, drove the long-term shift towards a high-oxygen, low CO 2 climate that eventually permitted the evolution of mammals and, ultimately, humans. However, very little is known about the productivity of the early terrestrial biosphere, which depended on the acquisition of the limiting nutrient phosphorus via fungal symbiosis. Recent laboratory experiments have shown that plant-fungal symbiotic function is specific to fungal identity, with carbon-for-phosphorus exchange being either enhanced or suppressed under superambient CO 2 By incorporating these experimental findings into a biogeochemical model, we show that the differences in these symbiotic nutrient acquisition strategies could greatly alter the plant-driven changes to climate, allowing drawdown of CO 2 to glacial levels, and altering the nature of the rise of oxygen. We conclude that an accurate depiction of plant-fungal symbiotic systems, informed by high-CO 2 experiments, is key to resolving the question of how the first terrestrial ecosystems altered our planet.This article is part of a discussion meeting issue 'The Rhynie cherts: our earliest terrestrial ecosystem revisited'. © 2017 The Authors.

  9. Formulation of a peach ice cream as potential symbiotic food

    Directory of Open Access Journals (Sweden)

    Fernando Josué VILLALVA

    Full Text Available Abstract Today’s population increasingly demands and consumes healthy products. For this reason, the food industry has been developing and marketing food with added bioactive components. The aim of this work was to formulate a peach ice cream reduced in calories with an added probiotic (Bifidobacterium lactis Bb-12 and prebiotics (inulin, and to evaluate its sensory quality and acceptability as potential symbiotic food. The moisture content was 76.47%; 7.14% protein; 0.15% fat; 6.37%; carbohydrates; 9.87% inulin; 1.22% ash; 0.201% calcium, 0.155% phosphorus and 0.168% sodium. On the first and 21th day of storage counts of B. lactis Bb – 12 was 4 x 108 CFU/mL and 1.5 x 107 CFU/mL, respectively. It was possible to formulate a peach ice cream reduced in calories, fat, and sugar and with potential symbiotic effect, by addition of B. lactis Bb – 12. A product with suitable organoleptic characteristics, creamy texture, peachy colour, taste and flavour, and no ice crystals was obtained. This ice cream would be a suitable food matrix to incorporate prebiotic and probiotic ingredients as a potential symbiotic food.

  10. Magnetic Bacteria.

    Science.gov (United States)

    Nelson, Jane Bray; Nelson, Jim

    1992-01-01

    Describes the history of Richard Blakemore's discovery of magnetotaxic organisms. Discusses possible reasons why the magnetic response in bacteria developed. Proposes research experiments integrating biology and physics in which students investigate problems using cultures of magnetotaxic organisms. (MDH)

  11. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria......, Thiomargarita namibiensis, with a diameter of 750 mum. All bacteria, including those that swim around in the environment, obtain their food molecules by molecular diffusion. Only the fastest and largest swimmers known, Thiovulum majus, are able to significantly increase their food supply by motility...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria...

  12. Big bacteria

    DEFF Research Database (Denmark)

    Schulz, HN; Jørgensen, BB

    2001-01-01

    A small number of prokaryotic species have a unique physiology or ecology related to their development of unusually large size. The biomass of bacteria varies over more than 10 orders of magnitude, from the 0.2 mum wide nanobacteria to the largest cells of the colorless sulfur bacteria...... and by actively creating an advective flow through the entire population. Diffusion limitation generally restricts the maximal size of prokaryotic cells and provides a selective advantage for mum-sized cells at the normally low substrate concentrations in the environment. The largest heterotrophic bacteria......, the 80 x 600 mum large Epulopiscium sp. from the gut of tropical fish, are presumably living in a very nutrient-rich medium. Many large bacteria contain numerous inclusions in the cells that reduce the volume of active cytoplasm. The most striking examples of competitive advantage from large cell size...

  13. Hessian fly-associated bacteria: transmission, essentiality, and composition.

    Directory of Open Access Journals (Sweden)

    Raman Bansal

    Full Text Available Plant-feeding insects have been recently found to use microbes to manipulate host plant physiology and morphology. Gall midges are one of the largest groups of insects that manipulate host plants extensively. Hessian fly (HF, Mayetiola destructor is an important pest of wheat and a model system for studying gall midges. To examine the role of bacteria in parasitism, a systematic analysis of bacteria associated with HF was performed for the first time. Diverse bacteria were found in different developmental HF stages. Fluorescent in situ hybridization detected a bacteriocyte-like structure in developing eggs. Bacterial DNA was also detected in eggs by PCR using primers targeted to different bacterial groups. These results indicated that HF hosted different types of bacteria that were maternally transmitted to the next generation. Eliminating bacteria from the insect with antibiotics resulted in high mortality of HF larvae, indicating that symbiotic bacteria are essential for the insect to survive on wheat seedlings. A preliminary survey identified various types of bacteria associated with different HF stages, including the genera Enterobacter, Pantoea, Stenotrophomonas, Pseudomonas, Bacillus, Ochrobactrum, Acinetobacter, Alcaligenes, Nitrosomonas, Arcanobacterium, Microbacterium, Paenibacillus, and Klebsiella. Similar bacteria were also found specifically in HF-infested susceptible wheat, suggesting that HF larvae had either transmitted bacteria into plant tissue or brought secondary infection of bacteria to the wheat host. The bacteria associated with wheat seedlings may play an essential role in the wheat-HF interaction.

  14. Locticacid bacteria: funcionality, polysaccharides, therapeutic potencial and applications in food

    Directory of Open Access Journals (Sweden)

    Olga Lucía Mondragón Bernal

    2008-06-01

    Full Text Available This review shows the recent acid lactic bacteria advances, their functional and therapeutic potential, synthesis of polisaccharides and their possibilities of application in the cultures of starter industry, foods and healthful-foods. There are included topics that go from the origin of the lactic acid bacteria (LAB, tipic and industrial products applications, their biological and genetic characteristics, description of a diverse number of strains, their main products of fermentation, with a greater approach in the exo-polisaccharides producing for the application in the food industry, as well as concepts and advances in functional food like the symbiotic ones, until the future perspective of researchs.

  15. Microevolution of symbiotic Bradyrhizobium populations associated with soybeans in east North America

    Science.gov (United States)

    Tang, Jie; Bromfield, E S P; Rodrigue, N; Cloutier, S; Tambong, J T

    2012-01-01

    Microevolution and origins of Bradyrhizobium populations associated with soybeans at two field sites (A and B, 280 km apart in Canada) with contrasting histories of inoculation was investigated using probabilistic analyses of six core (housekeeping) gene sequences. These analyses supported division of 220 isolates in five lineages corresponding either to B. japonicum groups 1 and 1a or to one of three novel lineages within the genus Bradyrhizobium. None of the isolates from site A and about 20% from site B (the only site with a recent inoculation history) were attributed to inoculation sources. The data suggest that most isolates were of indigenous origin based on sequence analysis of 148 isolates of soybean-nodulating bacteria from native legumes (Amphicarpaea bracteata and Desmodium canadense). Isolates from D. canadense clustered with B. japonicum group 1, whereas those from A. bracteata were placed in two novel lineages encountered at soybean field sites. One of these novel lineages predominated at soybean sites and exhibited a significant clonal expansion likely reflecting selection by the plant host. Homologous recombination events detected in the 35 sequence types from soybean sites had an effect on genetic diversification that was approximately equal to mutation. Interlineage transfer of core genes was infrequent and mostly attributable to gyrB that had a history of frequent recombination. Symbiotic gene sequences (nodC and nifH) of isolates from soybean sites and native legumes clustered in two lineages corresponding to B. japonicum and B. elkani with the inheritance of these genes appearing predominantly by vertical transmission. The data suggest that soybean-nodulating bacteria associated with native legumes represent a novel source of ecologically adapted bacteria for soybean inoculation. PMID:23301163

  16. Differences and Similarities of Soybean Defense-Related Genes Suppressed by Pathogenic and Symbiotic Bacteria

    Science.gov (United States)

    Bacterial effector proteins secreted through type III secretion systems (T3SS) play a crucial role in establishing plant and human diseases. Type III effectors have been shown to trigger defense responses when recognized by resistant plants, and to suppress defense responses in susceptible host plan...

  17. Purifying selection and molecular adaptation in the genome of Verminephrobacter, the heritable symbiotic bacteria of earthworms.

    Science.gov (United States)

    Kjeldsen, Kasper U; Bataillon, Thomas; Pinel, Nicolás; De Mita, Stéphane; Lund, Marie B; Panitz, Frank; Bendixen, Christian; Stahl, David A; Schramm, Andreas

    2012-01-01

    While genomic erosion is common among intracellular symbionts, patterns of genome evolution in heritable extracellular endosymbionts remain elusive. We study vertically transmitted extracellular endosymbionts (Verminephrobacter, Betaproteobacteria) that form a beneficial, species-specific, and evolutionarily old (60-130 Myr) association with earthworms. We assembled a draft genome of Verminephrobacter aporrectodeae and compared it with the genomes of Verminephrobacter eiseniae and two nonsymbiotic close relatives (Acidovorax). Similar to V. eiseniae, the V. aporrectodeae genome was not markedly reduced in size and showed no A-T bias. We characterized the strength of purifying selection (ω = dN/dS) and codon usage bias in 876 orthologous genes. Symbiont genomes exhibited strong purifying selection (ω = 0.09 ± 0.07), although transition to symbiosis entailed relaxation of purifying selection as evidenced by 50% higher ω values and less codon usage bias in symbiont compared with reference genomes. Relaxation was not evenly distributed among functional gene categories but was overrepresented in genes involved in signal transduction and cell envelope biogenesis. The same gene categories also harbored instances of positive selection in the Verminephrobacter clade. In total, positive selection was detected in 89 genes, including also genes involved in DNA metabolism, tRNA modification, and TonB-dependent iron uptake, potentially highlighting functions important in symbiosis. Our results suggest that the transition to symbiosis was accompanied by molecular adaptation, while purifying selection was only moderately relaxed, despite the evolutionary age and stability of the host association. We hypothesize that biparental transmission of symbionts and rare genetic mixing during transmission can prevent genome erosion in heritable symbionts.

  18. Symbiotic functioning and bradyrhizobial biodiversity of cowpea (Vigna unguiculata L. Walp. in Africa

    Directory of Open Access Journals (Sweden)

    Dakora Felix D

    2010-03-01

    Full Text Available Abstract Background Cowpea is the most important food grain legume in Sub-Saharan Africa. However, no study has so far assessed rhizobial biodiversity and/or nodule functioning in relation to strain IGS types at the continent level. In this study, 9 cowpea genotypes were planted in field experiments in Botswana, South Africa and Ghana with the aim of i trapping indigenous cowpea root-nodule bacteria (cowpea "rhizobia" in the 3 countries for isolation, molecular characterisation using PCR-RFLP analysis, and sequencing of the 16S - 23S rDNA IGS gene, ii quantifying N-fixed in the cowpea genotypes using the 15N natural abundance technique, and iii relating the levels of nodule functioning (i.e. N-fixed to the IGS types found inside nodules. Results Field measurements of N2 fixation revealed significant differences in plant growth, δ15N values, %Ndfa and amounts of N-fixed between and among the 9 cowpea genotypes in Ghana and South Africa. Following DNA analysis of 270 nodules from the 9 genotypes, 18 strain IGS types were found. Relating nodule function to the 18 IGS types revealed significant differences in IGS type N2-fixing efficiencies. Sequencing the 16S - 23S rDNA gene also revealed 4 clusters, with cluster 2 forming a distinct group that may be a new Bradyrhizobium species. Taken together, our data indicated greater biodiversity of cowpea bradyrhizobia in South Africa relative to Botswana and Ghana. Conclusions We have shown that cowpea is strongly dependant on N2 fixation for its N nutrition in both South Africa and Ghana. Strain IGS type symbiotic efficiency was assessed for the first time in this study, and a positive correlation was discernible where there was sole nodule occupancy. The differences in IGS type diversity and symbiotic efficiency probably accounts for the genotype × environment interaction that makes it difficult to select superior genotypes for use across Africa. The root-nodule bacteria nodulating cowpea in this study

  19. Use of DNA Markers for Investigating Sources of Bacteria in Contaminated Ground Water: Wooster Township, Wayne County, Ohio

    Science.gov (United States)

    Dumouchelle, Denise H.

    2006-01-01

    In 2004, a public-health nuisance was declared by the Wayne County Board of Health in the Scenic Heights Drive-Batdorf Road area of Wooster Township, Wayne County, Ohio, because of concerns about the safety of water from local wells. Repeated sampling had detected the presence of fecal-indicator bacteria and elevated nitrate concentrations. In June 2006, the U.S. Geological Survey (USGS), in cooperation with the Ohio Environmental Protection Agency (Ohio EPA), collected and analyzed samples from some of the affected wells to help investigate the possibility of human-origin bacterial contamination. Water samples from 12 wells and 5 home sewage-treatment systems (HSTS) were collected. Bromide concentrations were determined in samples from the 12 wells. Samples from 5 of the 12 wells were analyzed for wastewater compounds. Total coliform, enterococci and Escherichia coli (E. coli) bacteria concentrations were determined for samples from 8 of the 12 wells. In addition, two microbial source-tracking tools that employ DNA markers were used on samples from several wells and a composite sample of water from five septic tanks. The DNA markers from the Enterococcus faecium species and the order Bacteroidales are associated with specific sources, either human or ruminant sources. Bromide concentrations ranged from 0.04 to 0.18 milligrams per liter (mg/L). No wastewater compounds were detected at concentrations above the reporting limits. Samples from the 12 wells also were collected by Ohio EPA and analyzed for chloride and nitrate. Chloride concentrations ranged from 12.6 to 61.6 mg/L and nitrate concentrations ranged from 2.34 to 11.9 mg/L (as N). Total coliforms and enterococci were detected in samples from 8 wells, at concentrations from 2 to 200 colony-forming units per 100 milliliters (CFU/100 mL) and 0.5 to 17 CFU/100 mL, respectively. E. coli were detected in samples from three of the eight wells, at concentrations of 1 or 2 CFU/100 mL. Tests for the human

  20. Multiple I-Type Lysozymes in the Hydrothermal Vent Mussel Bathymodiolus azoricus and Their Role in Symbiotic Plasticity.

    Directory of Open Access Journals (Sweden)

    Camille Detree

    Full Text Available The aim of this study was first to identify lysozymes paralogs in the deep sea mussel Bathymodiolus azoricus then to measure their relative expression or activity in different tissue or conditions. B. azoricus is a bivalve that lives close to hydrothermal chimney in the Mid-Atlantic Ridge (MAR. They harbour in specialized gill cells two types of endosymbiont (gram-bacteria: sulphide oxidizing bacteria (SOX and methanotrophic bacteria (MOX. This association is thought to be ruled by specific mechanism or actors of regulation to deal with the presence of symbiont but these mechanisms are still poorly understood. Here, we focused on the implication of lysozyme, a bactericidal enzyme, in this endosymbiosis. The relative expression of Ba-lysozymes paralogs and the global anti-microbial activity, were measured in natural population (Lucky Strike--1700 m, Mid-Atlantic Ridge, and in in situ experimental conditions. B. azoricus individuals were moved away from the hydrothermal fluid to induce a loss of symbiont. Then after 6 days some mussels were brought back to the mussel bed to induce a re-acquisition of symbiotic bacteria. Results show the presence of 6 paralogs in B. azoricus. In absence of symbionts, 3 paralogs are up-regulated while others are not differentially expressed. Moreover the global activity of lysozyme is increasing with the loss of symbiont. All together these results suggest that lysozyme may play a crucial role in symbiont regulation.

  1. Protein-Injection Machines in Bacteria.

    Science.gov (United States)

    Galán, Jorge E; Waksman, Gabriel

    2018-03-08

    Many bacteria have evolved specialized nanomachines with the remarkable ability to inject multiple bacterially encoded effector proteins into eukaryotic or prokaryotic cells. Known as type III, type IV, and type VI secretion systems, these machines play a central role in the pathogenic or symbiotic interactions between multiple bacteria and their eukaryotic hosts, or in the establishment of bacterial communities in a diversity of environments. Here we focus on recent progress elucidating the structure and assembly pathways of these machines. As many of the interactions shaped by these machines are of medical importance, they provide an opportunity to develop novel therapeutic approaches to combat important human diseases. Copyright © 2018 Elsevier Inc. All rights reserved.

  2. Bacteria From Marine Sponges: A Source of New Drugs.

    Science.gov (United States)

    Bibi, Fehmida; Faheem, Muhammad; Azhar, Esam I; Yasir, Muhammad; Alvi, Sana A; Kamal, Mohammad A; Ullah, Ikram; Naseer, Muhammad I

    2017-01-01

    Sponges are rich source of bioactive natural products synthesized by the symbiotic bacteria belonging to different phyla. Due to a competition for space and nutrients the marine bacteria associated with sponges could produce more antibiotic substances. To explore the proactive potential of marine microbes extensive research has been done. These bioactive metabolites have some unique properties that are pharmaceutically important. For this review, we have performed a non-systematic search of the available literature though various online search engines. This review provides an insight that how majority of active metabolites have been identified from marine invertebrates of which sponges predominate. Sponges harbor abundant and diverse microorganisms, which are the sources of a range of marine bioactive metabolites. From sponges and their associated microorganisms, approximately 5,300 different natural compounds are known. Current research on sponge-microbe interaction and their active metabolites has become a focal point for many researchers. Various active metabolites derived from sponges are now known to be produced by their symbiotic microflora. In this review, we attempt to report the latest studies regarding capability of bacteria from sponges as producers of bioactive metabolite. Moreover, these sponge associated bacteria are an important source of different enzymes of industrial significance. In present review, we will address some novel approaches for discovering marine metabolites from bacteria that have the greatest potential to be used in clinical treatments. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  3. Symbiotic nitrogen fixation and nitrate uptake by the pea crop

    International Nuclear Information System (INIS)

    Jensen, E.S.

    1986-08-01

    Symbiotic nitrogen fixation and nitrate uptake by pea plants (Pisum sativum L.) were studied in field and pot experiments using the 15 N isotope dilution technique and spring barley as a non-fixing reference crop. Barley, although not ideal, seemed to be a suitable reference for pea in the 15 N-technique. Maximum N 2 fixation activity of 10 kg N fixed per ha per day was reached around the flat pod growth stage, and the activity decreased rapidly during pod-filling. The pea crop fixed between 100 and 250 kg N ha -1 , corresponding to from 45 to 80 per cent of total crop N. The amount of symbiotically fixed N 2 depended on the climatic conditions in the experimental year, the level of soil mineral N and the pea cultivar. Field-grown pea took up 60 to 70 per cent of the N-fertilizer supplied. The supply of 50 kg NO 3 -N ha -1 inhibited the N 2 fixation approximately 15 per cent. Small amounts of fertilizer N, supplied at sowing (starter-N), slightly stimulated the vegetative growth of pea, but the yields of seed dry matter and protein were not significantly influenced. In the present field experiments the environmental conditions, especially the distribution of rainfall during the growth season, seemed to be more important in determining the protein and dry matter yield of the dry pea crop, than the ability of pea to fix nitrogen symbiotically. However, fertilizer N supplied to pot-grown pea plants at the flat pod growth stage or as split applications significantly increased the yield of seed dry matter and protein. (author)

  4. Ad-hoc Symbiotic Interactive Displays through DLNA

    DEFF Research Database (Denmark)

    Bitsch, Jannick Elimar; Bouvin, Niels Olof

    2012-01-01

    - tructure means that the concept has seen little use. We design and implement a solution for using DLNA playback devices as symbiotic screens. DLNA devices are not designed to support interactive content, but to share and play media content in the home. Our work includes constructing a mechanism for real...... time generation of a video stream containing screen content, as well as a buffer starving mechanism that reduces buffer induced playback latency. The resulting system allows Android applications to use DLNA devices as a secondary screens. Latencies and update rates are such, that only applications...

  5. Microsatellite Primers in the Lichen Symbiotic Alga Trebouxia decolorans (Trebouxiophyceae

    Directory of Open Access Journals (Sweden)

    Francesco Dal Grande

    2013-03-01

    Full Text Available Premise of the study: Polymorphic microsatellite markers were developed for the symbiotic green alga Trebouxia decolorans to study fine-scale population structure and clonal diversity. Methods and Results: Using Illumina pyrosequencing, 20 microsatellite primer sets were developed for T. decolorans. The primer sets were tested on 43 individuals sampled from four subpopulations in Germany. The primers amplified di-, tri-, and tetranucleotide repeats with three to 15 alleles per locus, and the unbiased haploid diversity per locus ranged from 0.636 to 0.821. Conclusions: The identified microsatellite markers will be useful to study the genetic diversity, dispersal, and reproductive mode of this common lichen photobiont.

  6. A multi-frequency study of symbiotic stars: Pt. 1

    International Nuclear Information System (INIS)

    Ivison, R.J.; Bode, M.F.; Roberts, J.A.

    1991-01-01

    The relationship between optical line flux and 5 GHz radio flux is investigated for a sample of 17 northern sky symbiotic stars. Data were obtained near-simultaneously with the Manchester Echelle Spectrograph mounted on the Isaac Newton Telescope, La Palma and the Broad Band Interferometer at Jodrell Bank. Colour excesses, calculated from Balmer hydrogen line fluxes assuming Case B recombination ratios, are compared with other reddening estimates and also combined with extinction maps to provide improved distance estimates. Optical line fluxes are used in combination with radio fluxes to estimate physical parameters of these objects, including mass-loss rates. (author)

  7. The 1982 ultraviolet eclipse of the symbiotic binary AR Pav

    Science.gov (United States)

    Hutchings, J. B.; Cowley, A. P.; Ake, T. B.; Imhoff, C. L.

    1983-01-01

    Observations with the International Ultraviolet Explorer (IUE) of the symbiotic binary AR Pav through its 1982 eclipse show that the hot star is not eclipsed. The hot star is associated with an extended region of continuum emission which is partially eclipsed. The eclipsed radiation is hotter near to its center, with a maximum temperature of about 9000 K. The uneclipsed flux is hotter than this. UV emission lines are not measurably eclipsed and presumably arise in a much larger region than the continuum. These data provide new constraints on models of the system but also are apparently in contradiction to those based on ground-based data.

  8. On the nature of the symbiotic binary CI Cygni

    International Nuclear Information System (INIS)

    Kenyon, S.J.; Oliversen, N.A.; Mikolajewska, J.; Mikolajewski, M.; Stencel, R.E.

    1991-01-01

    An analysis of ultraviolet and optical spectroscopy is presented for the symbiotic binary CI Cyg. This system contains an M5 II asymptotic branch giant Mg of about 1.5 solar mass, transfering material at a few times 0.00001 solar mass/yr into a large accretion disk surrounding a main-sequence star with Mh of about 0.5 solar mass. A boundary layer at the inner edge of the disk photoionizes a small nebula approximately confined to the Roche volume of the accreting star. An extended, more highly ionized region forms when material ejected from the disk interacts with the red giant wind. 115 refs

  9. Symbiotic and nonsymbiotic hemoglobin genes of Casuarina glauca

    DEFF Research Database (Denmark)

    Jacobsen-Lyon, K; Jensen, Erik Østergaard; Jørgensen, Jan-Elo

    1995-01-01

    Casuarina glauca has a gene encoding hemoglobin (cashb-nonsym). This gene is expressed in a number of plant tissues. Casuarina also has a second family of hemoglobin genes (cashb-sym) expressed at a high level in the nodules that Casuarina forms in a nitrogen-fixing symbiosis with the actinomycete...... of the Casuarina gene. The finding that the nonsymbiotic Casuarina gene is also correctly expressed in L. corniculatus suggests to us that a comparable non-symbiotic hemoglobin gene will be found in legume species. Udgivelsesdato: 1995-Feb...

  10. Why bacteria matter in animal development and evolution.

    Science.gov (United States)

    Fraune, Sebastian; Bosch, Thomas C G

    2010-07-01

    While largely studied because of their harmful effects on human health, there is growing appreciation that bacteria are important partners for invertebrates and vertebrates, including man. Epithelia in metazoans do not only select their microbiota; a coevolved consortium of microbes enables both invertebrates and vertebrates to expand the range of diet supply, to shape the complex immune system and to control pathogenic bacteria. Microbes in zebrafish and mice regulate gut epithelial homeostasis. In a squid, microbes control the development of the symbiotic light organ. These discoveries point to a key role for bacteria in any metazoan existence, and imply that beneficial bacteria-host interactions should be considered an integral part of development and evolution.

  11. The value of biodiversity in legume symbiotic nitrogen fixation and nodulation for biofuel and food production.

    Science.gov (United States)

    Gresshoff, Peter M; Hayashi, Satomi; Biswas, Bandana; Mirzaei, Saeid; Indrasumunar, Arief; Reid, Dugald; Samuel, Sharon; Tollenaere, Alina; van Hameren, Bethany; Hastwell, April; Scott, Paul; Ferguson, Brett J

    2015-01-01

    Much of modern agriculture is based on immense populations of genetically identical or near-identical varieties, called cultivars. However, advancement of knowledge, and thus experimental utility, is found through biodiversity, whether naturally-found or induced by the experimenter. Globally we are confronted by ever-growing food and energy challenges. Here we demonstrate how such biodiversity from the food legume crop soybean (Glycine max L. Merr) and the bioenergy legume tree Pongamia (Millettia) pinnata is a great value. Legume plants are diverse and are represented by over 18,000 species on this planet. Some, such as soybean, pea and medics are used as food and animal feed crops. Others serve as ornamental (e.g., wisteria), timber (e.g., acacia/wattle) or biofuel (e.g., Pongamia pinnata) resources. Most legumes develop root organs (nodules) after microsymbiont induction that serve as their habitat for biological nitrogen fixation. Through this, nitrogen fertiliser demand is reduced by the efficient symbiosis between soil Rhizobium-type bacteria and the appropriate legume partner. Mechanistic research into the genetics, biochemistry and physiology of legumes is thus strategically essential for future global agriculture. Here we demonstrate how molecular plant science analysis of the genetics of an established food crop (soybean) and an emerging biofuel P. pinnata feedstock contributes to their utility by sustainable production aided by symbiotic nitrogen fixation. Crown Copyright © 2014. Published by Elsevier GmbH. All rights reserved.

  12. A nutrient-regulated, dual localization phospholipase A2 in the symbiotic fungus Tuber borchii

    Science.gov (United States)

    Soragni, Elisabetta; Bolchi, Angelo; Balestrini, Raffaella; Gambaretto, Claudio; Percudani, Riccardo; Bonfante, Paola; Ottonello, Simone

    2001-01-01

    Important morphogenetic transitions in fungi are triggered by starvation-induced changes in the expression of structural surface proteins. Here, we report that nutrient deprivation causes a strong and reversible up-regulation of TbSP1, a surface-associated, Ca2+-dependent phospholipase from the mycorrhizal fungus Tuber borchii. TbSP1 is the first phospholipase A2 to be described in fungi and identifies a novel class of phospholipid-hydrolyzing enzymes. The TbSP1 phospholipase, which is synthesized initially as a pre-protein, is processed efficiently and secreted during the mycelial phase. The mature protein, however, also localizes to the inner cell wall layer, close to the plasma membrane, in both free-living and symbiosis-engaged hyphae. It thus appears that a dual localization phospholipase A2 is involved in the adaptation of a symbiotic fungus to conditions of persistent nutritional limitation. Moreover, the fact that TbSP1-related sequences are present in Streptomyces and Neurospora, and not in wholly sequenced non-filamentous microorganisms, points to a general role for TbSP1 phospholipases A2 in the organization of multicellular filamentous structures in bacteria and fungi. PMID:11566873

  13. Genes and Gut Bacteria Involved in Luminal Butyrate Reduction Caused by Diet and Loperamide

    Directory of Open Access Journals (Sweden)

    Nakwon Hwang

    2017-11-01

    Full Text Available Unbalanced dietary habits and gut dysmotility are causative factors in metabolic and functional gut disorders, including obesity, diabetes, and constipation. Reduction in luminal butyrate synthesis is known to be associated with gut dysbioses, and studies have suggested that restoring butyrate formation in the colon may improve gut health. In contrast, shifts in different types of gut microbiota may inhibit luminal butyrate synthesis, requiring different treatments to restore colonic bacterial butyrate synthesis. We investigated the influence of high-fat diets (HFD and low-fiber diets (LFD, and loperamide (LPM administration, on key bacteria and genes involved in reduction of butyrate synthesis in mice. MiSeq-based microbiota analysis and HiSeq-based differential gene analysis indicated that different types of bacteria and genes were involved in butyrate metabolism in each treatment. Dietary modulation depleted butyrate kinase and phosphate butyryl transferase by decreasing members of the Bacteroidales and Parabacteroides. The HFD also depleted genes involved in succinate synthesis by decreasing Lactobacillus. The LFD and LPM treatments depleted genes involved in crotonoyl-CoA synthesis by decreasing Roseburia and Oscilllibacter. Taken together, our results suggest that different types of bacteria and genes were involved in gut dysbiosis, and that selected treatments may be needed depending on the cause of gut dysfunction.

  14. Genes and Gut Bacteria Involved in Luminal Butyrate Reduction Caused by Diet and Loperamide.

    Science.gov (United States)

    Hwang, Nakwon; Eom, Taekil; Gupta, Sachin K; Jeong, Seong-Yeop; Jeong, Do-Youn; Kim, Yong Sung; Lee, Ji-Hoon; Sadowsky, Michael J; Unno, Tatsuya

    2017-11-28

    Unbalanced dietary habits and gut dysmotility are causative factors in metabolic and functional gut disorders, including obesity, diabetes, and constipation. Reduction in luminal butyrate synthesis is known to be associated with gut dysbioses, and studies have suggested that restoring butyrate formation in the colon may improve gut health. In contrast, shifts in different types of gut microbiota may inhibit luminal butyrate synthesis, requiring different treatments to restore colonic bacterial butyrate synthesis. We investigated the influence of high-fat diets (HFD) and low-fiber diets (LFD), and loperamide (LPM) administration, on key bacteria and genes involved in reduction of butyrate synthesis in mice. MiSeq-based microbiota analysis and HiSeq-based differential gene analysis indicated that different types of bacteria and genes were involved in butyrate metabolism in each treatment. Dietary modulation depleted butyrate kinase and phosphate butyryl transferase by decreasing members of the Bacteroidales and Parabacteroides . The HFD also depleted genes involved in succinate synthesis by decreasing Lactobacillus . The LFD and LPM treatments depleted genes involved in crotonoyl-CoA synthesis by decreasing Roseburia and Oscilllibacter . Taken together, our results suggest that different types of bacteria and genes were involved in gut dysbiosis, and that selected treatments may be needed depending on the cause of gut dysfunction.

  15. Nonlegume Parasponia andersonii deploys a broad rhizobium host range strategy resulting in largely variable symbiotic effectiveness

    NARCIS (Netherlands)

    Camp, op den R.H.M.; Polone, E.; Fedorova, E.; Roelofsen, W.; Squartini, A.; Camp, op den H.J.M.; Bisseling, T.; Geurts, R.

    2012-01-01

    The non-legume genus Parasponia has evolved the rhizobium symbiosis independent from legumes and has done so only recently. We aim to study the promiscuity of such newly evolved symbiotic engagement and determine the symbiotic effectiveness of infecting rhizobium species. It was found that

  16. Effect of Subliminal Stimulation of Symbiotic Fantasies on College Student Self-Disclosure in Group Counseling.

    Science.gov (United States)

    Linehan, Edward; O'Toole, James

    1982-01-01

    Studied subliminal symbiotic stimulation as a treatment aid in conjunction with counselor self-disclosures in group counseling. Results showed that subliminal exposure to MOMMY AND I ARE ONE stimulus would lead to more client self-disclosures in group counseling. Suggests impact of symbiotic stimulus can be affected by counselor behavior. (RC)

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

    Directory of Open Access Journals (Sweden)

    Ryo Futahashi

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

  18. The response of Anabaena -free Azolla and the symbiotic Azolla to ...

    African Journals Online (AJOL)

    The performance of Anabaena-free (algae free) and symbiotic types of three speeies of Azolla (A. filiculoides, A. pinnata and A. microphylla) were studied in a phytotron at two average temperatures (22 and 33 oC). The growth of both the Anabaena-free and symbiotic types were depressed at a high temperature (33 DC) to ...

  19. Foliar Chlorosis in Symbiotic Host and Nonhost Plants Induced by Rhizobium tropici Type B Strains.

    Science.gov (United States)

    O'connell, K P; Handelsman, J

    1993-07-01

    Rhizobium tropici CIAT899 induced chlorosis in the leaves of its symbiotic hosts, common bean (Phaseolus vulgaris L.), siratro (Macroptilium atropurpureum Urb.), and Leucaena leucocephala (Lam.) de Wit. Chlorosis induction by strains CIAT899 and CT9005, an exopolysaccharide-deficient mutant of CIAT899, required carbon substrate. When the bacteria were added at planting in a solution of mannitol (50 g/liter), as few as 10 cells of CIAT899 were sufficient to induce chlorosis in bean plants. All carbon sources tested, including organic acids and mono- and disaccharides, supported chlorosis induction. The addition of a carbon source did not affect the growth rate or the population density of CT9005 in the bean plant rhizosphere. Cell-free filtrates of cultures of CT9005 did not induce detectable chlorosis. All type B strains of R. tropici tested also induced chlorosis in common bean. Type A strains of R. tropici and all other species of bacteria tested did not induce chlorosis. Several lines of evidence indicated that nodulation was not required for chlorosis induction. Strain RSP900, a pSym-cured derivative of CIAT899, induced chlorosis in wild-type P. vulgaris. In addition, NOD125, a nodulation-defective line of common bean, developed chlorosis when inoculated with CIAT899, but did not develop nodules. CIAT899 consistently induced severe chlorosis in the leaves of the nonhost legumes alfalfa (Medicago sativa L.) and Berseem clover (Trifolium alexandrinum L.), and induced chlorosis in 29 to 58% of the plants tested of sunflower, cucumber, and tomato seedlings, but it did not induce chlorosis in the leaves of corn or wheat. Chlorosis induction in nonhost plants also required carbon substrate. The data are consistent with the hypothesis that R. tropici type B strains produce a chlorosis-inducing factor that affects a wide range of plant species.

  20. Symbiotic propagation of seedlings of Cyrtopodium glutiniferum Raddi (Orchidaceae

    Directory of Open Access Journals (Sweden)

    Fernanda Aparecida Rodrigues Guimarães

    2013-09-01

    Full Text Available In nature, orchid seeds obtain the nutrients necessary for germination by degrading intracellular fungal structures formed after colonization of the embryo by mycorrhizal fungi. Protocols for asymbiotic germination of orchid seeds typically use media with high concentrations of soluble carbohydrate and minerals. However, when reintroduced into the field, seedlings obtained via asymbiotic germination have lower survival rates than do seedlings obtained via symbiotic germination. Tree fern fiber, the ideal substrate for orchid seedling acclimatization, is increasingly scarce. Here, we evaluated seed germination and protocorm development of Cyrtopodium glutiniferum Raddi cultivated in asymbiotic media (Knudson C and Murashige & Skoog and in oatmeal agar (OA medium inoculated with the mycorrhizal fungus Epulorhiza sp., using non-inoculated OA medium as a control. We also evaluated the performance of tree fern fiber, pine bark, eucalyptus bark, corncob and sawdust as substrates for the acclimatization of symbiotically propagated plants. We determined germination percentages, protocorm development and growth indices at 35 and 70 days of cultivation. Relative growth rates and the effects of substrates on mycorrhizal formation were calculated after 165 days of cultivation. Germination efficiency and growth indices were best when inoculated OA medium was used. Corncob and pine bark showed the highest percentages of colonized system roots. The OA medium inoculated with Epulorhiza sp. shows potential for C. glutiniferum seedling production. Corncob and pine bark are promising substitutes for tree fern fiber as substrates for the acclimatization of orchid seedlings.

  1. Concept evaluation of nuclear fusion driven symbiotic energy systems

    International Nuclear Information System (INIS)

    Renier, J.P.; Hoffman, T.J.

    1979-01-01

    This paper analyzes systems based on D-T and semi-catalyzed D-D fusion-powered U233 breeders. Two different blanket types were used: metallic thorium pebble-bed blankets with a batch reprocessing mode and a molten salt blanket with on-line continuous or batch reprocessing. All fusion-driven blankets are assumed to have spherical geometries, with a 85% closure. Neutronics depletion calculations were performed with a revised version of the discrete ordinates code XSDRN-PM, using multigroup (100 neutron, 21 gamma-ray groups) coupled cross-section libraries. These neutronics calculations are coupled with a scenario optimization and cost analysis code. Also, the fusion burn was shaped so as to keep the blanket maximum power density below a preset value, and to improve the performance of the fusion-driven systems. The fusion-driven symbiotes are compared with LMFBR-driven energy systems. The nuclear fission breeders that were used as drivers have parameters characteristic of heterogeneous, oxide LMFBRs. They are net plutonium users - the plutonium is obtained from the discharges of LWRs - and U233 is bred in the fission breeder thorium blankets. The analyses of the symbiotic energy systems were performed at equilibrium, at maximum rate of grid expansion, and for a given nuclear power demand

  2. Symbiotic symbolization by hand and mouth in sign language.

    Science.gov (United States)

    Sandler, Wendy

    2009-04-01

    Current conceptions of human language include a gestural component in the communicative event. However, determining how the linguistic and gestural signals are distinguished, how each is structured, and how they interact still poses a challenge for the construction of a comprehensive model of language. This study attempts to advance our understanding of these issues with evidence from sign language. The study adopts McNeill's criteria for distinguishing gestures from the linguistically organized signal, and provides a brief description of the linguistic organization of sign languages. Focusing on the subcategory of iconic gestures, the paper shows that signers create iconic gestures with the mouth, an articulator that acts symbiotically with the hands to complement the linguistic description of objects and events. A new distinction between the mimetic replica and the iconic symbol accounts for the nature and distribution of iconic mouth gestures and distinguishes them from mimetic uses of the mouth. Symbiotic symbolization by hand and mouth is a salient feature of human language, regardless of whether the primary linguistic modality is oral or manual. Speakers gesture with their hands, and signers gesture with their mouths.

  3. Symbiotic symbolization by hand and mouth in sign language*

    Science.gov (United States)

    Sandler, Wendy

    2010-01-01

    Current conceptions of human language include a gestural component in the communicative event. However, determining how the linguistic and gestural signals are distinguished, how each is structured, and how they interact still poses a challenge for the construction of a comprehensive model of language. This study attempts to advance our understanding of these issues with evidence from sign language. The study adopts McNeill’s criteria for distinguishing gestures from the linguistically organized signal, and provides a brief description of the linguistic organization of sign languages. Focusing on the subcategory of iconic gestures, the paper shows that signers create iconic gestures with the mouth, an articulator that acts symbiotically with the hands to complement the linguistic description of objects and events. A new distinction between the mimetic replica and the iconic symbol accounts for the nature and distribution of iconic mouth gestures and distinguishes them from mimetic uses of the mouth. Symbiotic symbolization by hand and mouth is a salient feature of human language, regardless of whether the primary linguistic modality is oral or manual. Speakers gesture with their hands, and signers gesture with their mouths. PMID:20445832

  4. 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

  5. Adaptive symbiotic organisms search (SOS algorithm for structural design optimization

    Directory of Open Access Journals (Sweden)

    Ghanshyam G. Tejani

    2016-07-01

    Full Text Available The symbiotic organisms search (SOS algorithm is an effective metaheuristic developed in 2014, which mimics the symbiotic relationship among the living beings, such as mutualism, commensalism, and parasitism, to survive in the ecosystem. In this study, three modified versions of the SOS algorithm are proposed by introducing adaptive benefit factors in the basic SOS algorithm to improve its efficiency. The basic SOS algorithm only considers benefit factors, whereas the proposed variants of the SOS algorithm, consider effective combinations of adaptive benefit factors and benefit factors to study their competence to lay down a good balance between exploration and exploitation of the search space. The proposed algorithms are tested to suit its applications to the engineering structures subjected to dynamic excitation, which may lead to undesirable vibrations. Structure optimization problems become more challenging if the shape and size variables are taken into account along with the frequency. To check the feasibility and effectiveness of the proposed algorithms, six different planar and space trusses are subjected to experimental analysis. The results obtained using the proposed methods are compared with those obtained using other optimization methods well established in the literature. The results reveal that the adaptive SOS algorithm is more reliable and efficient than the basic SOS algorithm and other state-of-the-art algorithms.

  6. Fatty acid variations in symbiotic dinoflagellates from Okinawan corals.

    Science.gov (United States)

    Zhukova, Natalia V; Titlyanov, Eduard A

    2003-01-01

    The fatty acid composition of polar lipids and triacylglycerols was determined in different morphophysiological types of symbiotic dinoflagellates (SD) isolated from the hydrocoral Millepora intricata and the scleractinian corals Pocillopora damicornis, Seriatopora caliendrum, Seriatopora hystrix and Stylophora pistillata from a fringing reef of Sesoko Island, Okinawa, Japan. The distribution of the fatty acids among the morphophysiologically distinct types of SD reported in these corals makes it possible to readily distinguish one type of SD from the other. Moreover, differences were found both in polar lipids and triacylglycerols. The polar lipids of SD from M. intricata showed a very distinctive fatty acid profile. A combination of large proportions of 18:4 (n-3), 18:5 (n-3), 22:5 (n-6), and 22:6 (n-3) and negligible amounts of 20:4 (n-6), and 20:5 (n-3) in SD from M. intricata was particularly noteworthy. The fatty acid profiles of SD from P. damicornis and SD isolated from S. caliendrum and S. hystrix differed in the proportion of 18:4 (n-3) and 22:6 (n-3). It is suggested that fatty acids might provide useful information on possible taxonomic differences among symbiotic dinoflagellates. It is assumed that biochemical differences can reflect the genetic diversity of the morphophysiological types of SD associated with several species of hermatypic corals from this region.

  7. A single evolutionary innovation drives the deep evolution of symbiotic N2-fixation in angiosperms

    Science.gov (United States)

    Werner, Gijsbert D. A.; Cornwell, William K.; Sprent, Janet I.; Kattge, Jens; Kiers, E. Toby

    2014-01-01

    Symbiotic associations occur in every habitat on earth, but we know very little about their evolutionary histories. Current models of trait evolution cannot adequately reconstruct the deep history of symbiotic innovation, because they assume homogenous evolutionary processes across millions of years. Here we use a recently developed, heterogeneous and quantitative phylogenetic framework to study the origin of the symbiosis between angiosperms and nitrogen-fixing (N2) bacterial symbionts housed in nodules. We compile the largest database of global nodulating plant species and reconstruct the symbiosis’ evolution. We identify a single, cryptic evolutionary innovation driving symbiotic N2-fixation evolution, followed by multiple gains and losses of the symbiosis, and the subsequent emergence of ‘stable fixers’ (clades extremely unlikely to lose the symbiosis). Originating over 100 MYA, this innovation suggests deep homology in symbiotic N2-fixation. Identifying cryptic innovations on the tree of life is key to understanding the evolution of complex traits, including symbiotic partnerships. PMID:24912610

  8. Multi Groups Cooperation based Symbiotic Evolution for TSK-type Neuro-Fuzzy Systems Design.

    Science.gov (United States)

    Cheng, Yi-Chang; Hsu, Yung-Chi; Lin, Sheng-Fuu

    2010-07-01

    In this paper, a TSK-type neuro-fuzzy system with multi groups cooperation based symbiotic evolution method (TNFS-MGCSE) is proposed. The TNFS-MGCSE is developed from symbiotic evolution. The symbiotic evolution is different from traditional GAs (genetic algorithms) that each chromosome in symbiotic evolution represents a rule of fuzzy model. The MGCSE is different from the traditional symbiotic evolution; with a population in MGCSE is divided to several groups. Each group formed by a set of chromosomes represents a fuzzy rule and cooperate with other groups to generate the better chromosomes by using the proposed cooperation based crossover strategy (CCS). In this paper, the proposed TNFS-MGCSE is used to evaluate by numerical examples (Mackey-Glass chaotic time series and sunspot number forecasting). The performance of the TNFS-MGCSE achieves excellently with other existing models in the simulations.

  9. Effects of removing symbiotic green algae on the response of Hydra viridissima (Pallas 1776) to metals.

    Science.gov (United States)

    Karntanut, W; Pascoe, D

    2005-03-01

    Hydra viridissima is distinctively green due to symbiotic algae within the endodermal cells. The current investigation was designed to see if these algae influenced the response of Hydra to pollutants, by comparing the toxicity of copper, cadmium, and zinc to both symbiotic and aposymbiotic (free of their endosymbiotic algae) H. viridissima. The results demonstrated that the toxicity of the metals was generally similar for both groups of Hydra. However, at the lowest copper concentrations there was a difference between the two group of polyps, with aposymbiotic animals dying at concentrations where symbiotic Hydra survived. The lowest observed effect concentrations were 0.0068 and 0.016 mg/L for aposymbiotic and symbiotic Hydra, respectively. It is suggested that the symbiotic Hydra derive benefits from the association that enable them to better tolerate the toxicant. This work demonstrated that experimental manipulation of symbionts can help to explain their complex interactions and the ways in which they respond to pollutants.

  10. Occurrence and Localization of Phycoerythrin in Symbiotic Nostoc of Cycas revoluta and in the Free-Living Isolated Nostoc 7422.

    Science.gov (United States)

    Lindblad, P; Bergman, B

    1989-03-01

    The phycobiliprotein phycoerythrin was localized in symbiotic and free-living Nostoc of the cycad Cycas using immunocytochemistry. In symbiotic Nostoc, phycoerythrin was associated with the thylakoid membranes of vegetative cells and absent from heterocysts. Similar cellular/subcellular localization was observed between symbiotic Nostoc and the free-living Cycas isolate Nostoc 7422.

  11. Sources of fecal indicator bacteria to groundwater, Malibu Lagoon and the near-shore ocean, Malibu, California, USA

    Science.gov (United States)

    Izbicki, John A.; Swarzenski, Peter W.; Burton, Carmen A.; Van De Werfhorst, Laurie; Holden, Patricia A.; Dubinsky, Eric A.

    2012-01-01

    Onsite wastewater treatment systems (OWTS) used to treat residential and commercial sewage near Malibu, California have been implicated as a possible source of fecal indicator bacteria (FIB) to Malibu Lagoon and the near-shore ocean. For this to occur, treated wastewater must first move through groundwater before discharging to the Lagoon or ocean. In July 2009 and April 2010, δ18O and δD data showed that some samples from water-table wells contained as much as 70% wastewater; at that time FIB concentrations in those samples were generally less than the detection limit of 1 Most Probable Number (MPN) per 100 milliliters (mL). In contrast, Malibu Lagoon had total coliform, Escherichia coli, and enterococci concentrations as high as 650,000, 130,000, and 5,500 MPN per 100 mL, respectively, and as many as 12% of samples from nearby ocean beaches exceeded the U.S. Environmental Protection Agency single sample enterococci standard for marine recreational water of 104 MPN per 100 mL. Human-associated Bacteroidales, an indicator of human-fecal contamination, were not detected in water from wells, Malibu Lagoon, or the near-shore ocean. Similarly, microarray (PhyloChip) data show Bacteroidales and Fimicutes Operational Taxanomic Units (OTUs) present in OWTS were largely absent in groundwater; in contrast, 50% of Bacteroidales and Fimicutes OTUs present in the near-shore ocean were also present in gull feces. Terminal-Restriction Length Fragment Polymorphism (T-RFLP) and phospholipid fatty acid (PLFA) data showed that microbial communities in groundwater were different and less abundant than communities in OWTS, Malibu Lagoon, or the near-shore ocean. However, organic compounds indicative of wastewater (such as fecal sterols, bisphenol-A and cosmetics) were present in groundwater having a high percentage of wastewater and were present in groundwater discharging to the ocean. FIB in the near-shore ocean varied with tides, ocean swells, and waves. Movement of water from

  12. Identifying abnormalities in symbiotic development between Trifolium spp. and Rhizobium leguminosarum bv. trifolii leading to sub-optimal and ineffective nodule phenotypes

    Science.gov (United States)

    Melino, V. J.; Drew, E. A.; Ballard, R. A.; Reeve, W. G.; Thomson, G.; White, R. G.; O'Hara, G. W.

    2012-01-01

    Background and Aims Legumes overcome nitrogen limitations by entering into a mutualistic symbiosis with N2-fixing bacteria (rhizobia). Fully compatible associations (effective) between Trifolium spp. and Rhizobium leguminosarum bv. trifolii result from successful recognition of symbiotic partners in the rhizosphere, root hair infection and the formation of nodules where N2-fixing bacteroids reside. Poorly compatible associations can result in root nodule formation with minimal (sub-optimal) or no (ineffective) N2-fixation. Despite the abundance and persistence of strains in agricultural soils which are poorly compatible with the commercially grown clover species, little is known of how and why they fail symbiotically. The aims of this research were to determine the morphological aberrations occurring in sub-optimal and ineffective clover nodules and to determine whether reduced bacteroid numbers or reduced N2-fixing activity is the main cause for the Sub-optimal phenotype. Methods Symbiotic effectiveness of four Trifolium hosts with each of four R. leguminosarum bv. trifolii strains was assessed by analysis of plant yields and nitrogen content; nodule yields, abundance, morphology and internal structure; and bacteroid cytology, quantity and activity. Key Results Effective nodules (Nodule Function 83–100 %) contained four developmental zones and N2-fixing bacteroids. In contrast, Sub-optimal nodules of the same age (Nodule Function 24–57 %) carried prematurely senescing bacteroids and a small bacteroid pool resulting in reduced shoot N. Ineffective-differentiated nodules carried bacteroids aborted at stage 2 or 3 in differentiation. In contrast, bacteroids were not observed in Ineffective-vegetative nodules despite the presence of bacteria within infection threads. Conclusions Three major responses to N2-fixation incompatibility between Trifolium spp. and R. l. trifolii strains were found: failed bacterial endocytosis from infection threads into plant cortical

  13. Nitrogen acquisition in Agave tequilana from degradation of endophytic bacteria.

    Science.gov (United States)

    Beltran-Garcia, Miguel J; White, James F; Prado, Fernanda M; Prieto, Katia R; Yamaguchi, Lydia F; Torres, Monica S; Kato, Massuo J; Medeiros, Marisa H G; Di Mascio, Paolo

    2014-11-06

    Plants form symbiotic associations with endophytic bacteria within tissues of leaves, stems, and roots. It is unclear whether or how plants obtain nitrogen from these endophytic bacteria. Here we present evidence showing nitrogen flow from endophytic bacteria to plants in a process that appears to involve oxidative degradation of bacteria. In our experiments we employed Agave tequilana and its seed-transmitted endophyte Bacillus tequilensis to elucidate organic nitrogen transfer from (15)N-labeled bacteria to plants. Bacillus tequilensis cells grown in a minimal medium with (15)NH4Cl as the nitrogen source were watered onto plants growing in sand. We traced incorporation of (15)N into tryptophan, deoxynucleosides and pheophytin derived from chlorophyll a. Probes for hydrogen peroxide show its presence during degradation of bacteria in plant tissues, supporting involvement of reactive oxygen in the degradation process. In another experiment to assess nitrogen absorbed as a result of endophytic colonization of plants we demonstrated that endophytic bacteria potentially transfer more nitrogen to plants and stimulate greater biomass in plants than heat-killed bacteria that do not colonize plants but instead degrade in the soil. Findings presented here support the hypothesis that some plants under nutrient limitation may degrade and obtain nitrogen from endophytic microbes.

  14. Aerobic degradation of methyl tert-butyl ether in a closed symbiotic system containing a mixed culture of Chlorella ellipsoidea and Methylibium petroleiphilum PM1.

    Science.gov (United States)

    Zhong, Weihong; Li, Yixiao; Sun, Kedan; Jin, Jing; Li, Xuanzhen; Zhang, Fuming; Chen, Jianmeng

    2011-01-30

    The contamination of groundwater by methyl tert-butyl ether (MTBE) is one of the most serious environmental problems around the world. MTBE degradation in a closed algal-bacterial symbiotic system, containing a mixed culture of Methylibium petroleiphilum PM1 and Chlorella ellipsoidea, was investigated. The algal-bacterial symbiotic system showed increased MTBE degradation. The MTBE-degradation rate in the mixed culture (8.808 ± 0.007 mg l(-1) d(-1)) was higher than that in the pure bacterial culture (5.664 ± 0.017 mg l(-1) d(-1)). The level of dissolved oxygen was also higher in the mixed culture than that in the pure bacterial culture. However, the improved efficiency of MTBE degradation was not in proportional to the biomass of the alga. The optimal ratio of initial cell population of bacteria to algae was 100:1. An immobilized culture of mixed bacteria and algae also showed higher MTBE degradation rate than the immobilized pure bacterial culture. A mixed culture with algae and PM1 immobilized separately in different gel beads showed higher degradation rate (8.496 ± 0.636 mg l(-1) d(-1)) than that obtained with algae and PM1 immobilized in the same gel beads (5.424 ± 0.010 mg l(-1) d(-1)). Copyright © 2010 Elsevier B.V. All rights reserved.

  15. SEARCHING FOR NEW YELLOW SYMBIOTIC STARS: POSITIVE IDENTIFICATION OF StHα63

    Energy Technology Data Exchange (ETDEWEB)

    Baella, N. O. [Unidad de Astronomía, Instituto Geofísico del Perú, Lima, Per (Peru); Pereira, C. B.; Alvarez-Candal, A. [Observatório Nacional/MCTI, Rua Gen. José Cristino, 77, 20921-400, Rio de Janeiro (Brazil); Miranda, L. F., E-mail: nobar.baella@gmail.com, E-mail: claudio@on.br, E-mail: alvarez@on.br, E-mail: lfm@iaa.es [Instituto de Astrofísica de Andalucía- CSIC, C/Glorieta de la Astronomía s/n, E-18008 Granada (Spain)

    2016-04-15

    Yellow symbiotic stars are useful targets for probing whether mass transfer has happened in their binary systems. However, the number of known yellow symbiotic stars is very scarce. We report spectroscopic observations of five candidate yellow symbiotic stars that were selected by their positions in the 2MASS (J − H) versus (H − K{sub s}) diagram and which were included in some emission-line catalogs. Among the five candidates, only StHα63 is identified as a new yellow symbiotic star because of its spectrum and its position in the [TiO]{sub 1}–[TiO]{sub 2} diagram, which indicates a K4–K6 spectral type. In addition, the derived electron density (∼10{sup 8.4} cm{sup −3}) and several emission-line intensity ratios provide further support for that classification. The other four candidates are rejected as symbiotic stars because three of them actually do not show emission lines and the fourth one only Balmer emission lines. We also found that the WISE W3–W4 index clearly separates normal K-giants from yellow symbiotic stars and therefore can be used as an additional tool for selecting candidate yellow symbiotic stars.

  16. [Response of arbuscular mycorrhizal fungal lipid metabolism to symbiotic signals in mycorrhiza].

    Science.gov (United States)

    Tian, Lei; Li, Yuanjing; Tian, Chunjie

    2016-01-04

    Arbuscular mycorrhizal (AM) fungi play an important role in energy flow and nutrient cycling, besides their wide distribution in the cosystem. With a long co-evolution, AM fungi and host plant have formed a symbiotic relationship, and fungal lipid metabolism may be the key point to find the symbiotic mechanism in arbusculart mycorrhiza. Here, we reviewed the most recent progress on the interaction between AM fungal lipid metabolism and symbiotic signaling networks, especially the response of AM fungal lipid metabolism to symbiotic signals. Furthermore, we discussed the response of AM fungal lipid storage and release to symbiotic or non-symbiotic status, and the correlation between fungal lipid metabolism and nutrient transfer in mycorrhiza. In addition, we explored the feedback of the lipolysis process to molecular signals during the establishment of symbiosis, and the corresponding material conversion and energy metabolism besides the crosstalk of fungal lipid metabolism and signaling networks. This review will help understand symbiotic mechanism of arbuscular mycorrhiza fungi and further application in ecosystem.

  17. Transformation of leguminous plants to study symbiotic interactions.

    Science.gov (United States)

    Iantcheva, Anelia; Mysore, Kirankumar S; Ratet, Pascal

    2013-01-01

    Legume plants are important in agriculture because they represent an important source of protein for human and animal consumption. This high protein content results from their capacity to use atmospheric nitrogen for their nutrition as a consequence of their symbiotic interaction with rhizobia. Understanding this interaction at the molecular level is a prerequisite for its better use in agriculture and for the long term objective of its transfer to other crops. Agrobacterium-mediated transformation is a tool of choice for studying this interaction and for unraveling the function of the different genes discovered through classical genetic approaches. However, legume plants are often recalcitrant to regeneration and transformation. This paper describes the technology developments (regeneration, transformation, insertion mutagenesis) related to Agrobacterium transformations that were established in the legume plants, as well as different examples of the technology developments or gene discoveries resulting from these studies.

  18. Effects of subliminal symbiotic stimuli on anxiety reduction.

    Science.gov (United States)

    Malik, R; Krasney, M S; Aldworth, B; Ladd, H W

    1996-06-01

    The present study assessed the effectiveness of subliminal psychodynamic stimuli in reducing anxiety. 50 male and 50 female college students were tachistoscopically exposed to one of five stimuli: MOMMY AND I ARE ONE, DADDY AND I ARE ONE, I AM HAPPY WITH MYSELF, ONE, or a control stimulus MYMMO NAD I REA ENO. It was hypothesized that men would show a significant decrease in anxiety to the MOMMY stimulus, while women were expected to respond favorably to either the MOMMY or DADDY stimulus, or to both. Results showed that the subliminal stimuli did not produce differential effects on anxiety. This finding did not support previous claims for subliminal psychodynamic activation that the stimulation of symbiotic fantasy with the maternal figure produces positive behavioral effects. Despite this negative finding women's response to the MOMMY message was predicted by measures of self-perception.

  19. An update on probiotics, prebiotics and symbiotics in clinical nutrition.

    Science.gov (United States)

    Olveira, Gabriel; González-Molero, Inmaculada

    2016-11-01

    The concept of prebiotics, probiotics, and symbiotics and their use in different situations of daily clinical practice related to clinical nutrition is reviewed, as well as their role in the treatment/prevention of diarrhea (acute, induced by antibiotics, secondary to radiotherapy), inflammatory bowel disease (ulcerative colitis and pouchitis), in colonic health (constipation, irritable bowel), in liver disease (steatosis and minimum encephalopathy), and in intensive care, surgical, and liver transplantation. While their effectiveness for preventing antibiotic-induced diarrhea and pouchitis in ulcerative colitis appears to be shown, additional studies are needed to establish recommendations in most clinical settings. The risk of infection associated to use of probiotics is relatively low; however, there are selected groups of patients in whom they should be used with caution (as jejunum infusion). Copyright © 2016 SEEN. Publicado por Elsevier España, S.L.U. All rights reserved.

  20. The 1984 eclipse of the symbiotic binary SY Muscae

    Science.gov (United States)

    Kenyon, S. J.; Michalitisianos, A. G.; Lutz, J. H.; Kafatos, M.

    1985-01-01

    Data from IUE spectra obtained with the 10 x 20-arcsec aperture on May 13, 1984, and optical spectrophotometry obtained with an SIT vidicon on the 1.5-m telescope at CTIO on April 29-May 1, 1984, are reported for the symbiotic binary SY Mus. The data are found to be consistent with a model of a red-giant secondary of 60 solar radii which completely eclipses the hot primary every 627 d but only partially eclipses the 75-solar-radius He(+) region surrounding the primary. The distance to SY Mus is estimated as 1.3 kpc. It is suggested that the large Balmer decrement in eclipse, with (H-alpha)/(H-beta) = 8.3 and (H-beta)/(H-gamma) = 1.5, is associated with an electron density of about 10 to the 10th/cu cm.

  1. On the nature of the symbiotic star BF Cygni

    International Nuclear Information System (INIS)

    Mikolajewska, J.; Mikolajewski, M.; Kenyon, S.J.

    1989-01-01

    Optical and ultraviolet spectroscopy of the symbiotic binary BF Cyg obtained during 1979-1988 is discussed. This system consists of a low-mass M5 giant filling about 50 percent of its tidal volume and a hot, luminous compact object similar to the central star of a planetary nebula. The binary is embedded in an asymmetric nebula which includes a small, high-density region and an extended region of lower density. The larger nebula is formed by a slow wind ejected by the cool component and ionized by the hot star, while the more compact nebula is material expelled by the hot component in the form of a bipolar wind. The analysis indicates that disk accretion is essential to maintain the nuclear burning shell of the hot star. 84 refs

  2. Phagocytic activities of hemocytes from the deep-sea symbiotic mussels Bathymodiolus japonicus, B. platifrons, and B. septemdierum.

    Science.gov (United States)

    Tame, Akihiro; Yoshida, Takao; Ohishi, Kazue; Maruyama, Tadashi

    2015-07-01

    Deep-sea mytilid mussels harbor symbiotic bacteria in their gill epithelial cells that are horizontally or environmentally transmitted to the next generation of hosts. To understand the immune defense system in deep-sea symbiotic mussels, we examined the hemocyte populations of the symbiotic Bathymodiolus mussel species Bathymodiolus japonicus, Bathymodiolus platifrons, and Bathymodiolus septemdierum, and characterized three types of hemocytes: agranulocytes (AGs), basophilic granulocytes (BGs), and eosinophilic granulocytes (EGs). Of these, the EG cells were the largest (diameter, 8.4-10.0 μm) and had eosinophilic cytoplasm with numerous eosinophilic granules (diameter, 0.8-1.2 μm). Meanwhile, the BGs were of medium size (diameter, 6.7-8.0 μm) and contained small basophilic granules (diameter, 0.3-0.4 μm) in basophilic cytoplasm, and the AGs, the smallest of the hemocytes (diameter, 4.8-6.0 μm), had basophilic cytoplasm lacking granules. A lectin binding assay revealed that concanavalin A bound to all three hemocyte types, while wheat germ agglutinin bound exclusively to EGs and BGs. The total hemocyte population densities within the hemolymph of all three Bathymodiolus mussel species were similar (8.4-13.3 × 10(5) cells/mL), and the percentages of circulating AGs, BGs, and EGs in the hemolymph of these organisms were 44.7-48.5%, 14.3-17.6%, and 34.3-41.0%, respectively. To analyze the functional differences between these hemocytes, the phagocytic activity and post-phagocytic phagosome-lysosome fusion events were analyzed in each cell type using a fluorescent Alexa Fluor(®) 488-conjugated Escherichia coli bioparticle and a LysoTracker(®) lysosomal marker, respectively. While the AGs exhibited no phagocytic activity, both types of granulocytes were phagocytic. Of the three hemocyte types, the EGs exhibited the highest level of phagocytic activity as well as rapid phagosome-lysosome fusion, which occurred within 2 h of incubation. Meanwhile, the BGs showed

  3. The Rhizobium meliloti putA gene: its role in the establishment of the symbiotic interaction with alfalfa.

    Science.gov (United States)

    Jiménez-Zurdo, J I; García-Rodríguez, F M; Toro, N

    1997-01-01

    Little is known about the energy sources used by rhizobia during colonization, invasion and root nodule formation on leguminous plants. We have recently reported that an impaired proline metabolism in rhizobium meliloti leads to a reduced nodulation efficiency and competitiveness on alfalfa roots. In the present study we have characterized the R. meliloti proline dehydrogenase gene (putA) and addressed the question of its role in symbiosis. This rhizobial gene encodes a 1224-amino-acid-long polypeptide which is homologous to enteric bacteria, Rhodobacter capsulatus and Bradyrhizobium japonicum PutA proteins. Like the situation in these bacteria, sequence analysis identified the proline dehydrogenase (PDH) and pyrroline-5-carboxylate dehydrogenase (P5CDH) domains in the R. meliloti putA-encoded protein. Beta-galactosidase assays performed with free-living cells carrying a putA-lacZ transcriptional fusion revealed that R. meliloti putA gene expression is induced by proline, autoregulated by its encoded product, and independent of the general nitrogen regulatory system (Ntr). In addition, analysis of putA expression during the different steps of the symbiotic interaction with alfalfa showed that expression of this gene is turned on by the root exudates (RE), during root invasion and nodule formation, but not in differentiated nitrogen-fixing bacteroids. Furthermore, we show that the PutA- phenotype leads to a significant reduction of alfalfa root colonization by R. meliloti.

  4. Bradyrhizobium ottawaense sp. nov., a symbiotic nitrogen fixing bacterium from root nodules of soybeans in Canada.

    Science.gov (United States)

    Yu, Xiumei; Cloutier, Sylvie; Tambong, James T; Bromfield, Eden S P

    2014-09-01

    Sixteen strains of symbiotic bacteria from root nodules of Glycine max grown in Ottawa, Canada, were previously characterized and placed in a novel group within the genus Bradyrhizobium. To verify their taxonomic status, these strains were further characterized using a polyphasic approach. All strains possessed identical 16S rRNA gene sequences that were 99.79 % similar to the closest relative, Bradyrhizobium liaoningense LMG 18230(T). Phylogenetic analysis of concatenated atpD, glnII, recA, gyrB, rpoB and dnaK genes divided the 16 strains into three multilocus sequence types that were placed in a highly supported lineage distinct from named species of the genus Bradyrhizobium consistent with results of DNA-DNA hybridization. Based on analysis of symbiosis gene sequences (nodC and nifH), all novel strains were placed in a phylogenetic group with five species of the genus Bradyrhizobium that nodulate soybeans. The combination of phenotypic characteristics from several tests including carbon and nitrogen source utilization and antibiotic resistance could be used to differentiate representative strains from recognized species of the genus Bradyrhizobium. Novel strain OO99(T) elicits effective nodules on Glycine max, Glycine soja and Macroptilium atropurpureum, partially effective nodules on Desmodium canadense and Vigna unguiculata, and ineffective nodules on Amphicarpaea bracteata and Phaseolus vulgaris. Based on the data presented, we conclude that our strains represent a novel species for which the name Bradyrhizobium ottawaense sp. nov. is proposed, with OO99(T) ( = LMG 26739(T) = HAMBI 3284(T)) as the type strain. The DNA G+C content is 62.6 mol%. © 2014 Her Majesty the Queen in right of Canada as represented by the Minister of AAFC.

  5. Effect of phosphoglycerate mutase and fructose 1,6-bisphosphatase deficiency on symbiotic Burkholderia phymatum.

    Science.gov (United States)

    Chen, Wen-Ming; Prell, Jurgen; James, Euan K; Sheu, Der-Shyan; Sheu, Shih-Yi

    2012-04-01

    Burkholderia phymatum STM815 is a β-rhizobial strain that can effectively nodulate several species of the large legume genus Mimosa. Two Tn5-induced mutants of this strain, KM16-22 and KM51, failed to form root nodules on Mimosa pudica, but still caused root hair deformation, which is one of the early steps of rhizobial infection. Both mutants grew well in a complex medium. However, KM16-22 could not grow on minimal medium unless a sugar and a metabolic intermediate such as pyruvate were provided, and KM51 also could not grow on minimal medium unless a sugar was added. The Tn5-interrupted genes of the mutants showed strong homologies to pgm, which encodes 2,3-biphosphoglycerate-dependent phosphoglycerate mutase (dPGM), and fbp, which encodes fructose 1,6-bisphosphatase (FBPase). Both enzymes are known to be involved in obligate steps in carbohydrate metabolism. Enzyme assays confirmed that KM16-22 and KM51 had indeed lost dPGM and FBPase activity, respectively, whilst the activities of these enzymes were expressed normally in both free-living bacteria and symbiotic bacteroids of the parental strain STM815. Both mutants recovered their enzyme activity after the introduction of wild-type pgm or fbp genes, were subsequently able to use carbohydrate as a carbon source, and were able to form root nodules on M. pudica and to fix nitrogen as efficiently as the parental strain. We conclude that the enzymes dPGM and FBPase are essential for the formation of a symbiosis with the host plant.

  6. Enhanced rhizobial symbiotic capacity in an allopolyploid species of Glycine (Leguminosae).

    Science.gov (United States)

    Powell, Adrian F; Doyle, Jeff J

    2016-10-01

    Previous studies have shown that polyploidy can alter biotic interactions, and it has been suggested that these effects may contribute to the increased ability for colonization of new habitats shown by many allopolyploids. Little is known, however, about the effects of allopolyploidy, which combines hybridity and genome doubling, on symbiotic interactions with rhizobial bacteria. We examined interactions of the allopolyploid Glycine dolichocarpa (designated T2) with novel rhizobial partners, such as might occur in a context of colonization, and compared these with the responses of its diploid progenitors, G. tomentella (D3) and G. syndetika (D4). We assessed root hair response, nodule formation, nodule mass, nodule number, and plant biomass. The allopolyploid (T2) showed a greater root hair deformation response when exposed to rhizobia, compared with either diploid. T2 had a greater probability of forming nodules with NGR234 compared with diploid D4, and greater total nodule mass per nodulated plant compared with diploid D3. T2 also had greater plant biomass responses to nitrogen and when exposed to NGR234. The allopolyploid is characterized by transgressive responses to rhizobia for some variables, while also combining certain parental diploid responses such that its capacity for interactions with rhizobia appears to be greater than for either diploid progenitor. This overall enhanced nodulation capacity and the ability to make greater gains from exposure to both rhizobia and additional nitrogen indicate a greater potential of the allopolyploid to benefit from these factors both generally and in a context of colonization. © 2016 Botanical Society of America.

  7. Bradyrhizobium ottawaense sp. nov., a symbiotic nitrogen fixing bacterium from root nodules of soybeans in Canada

    Science.gov (United States)

    Yu, Xiumei; Cloutier, Sylvie; Tambong, James T.

    2014-01-01

    Sixteen strains of symbiotic bacteria from root nodules of Glycine max grown in Ottawa, Canada, were previously characterized and placed in a novel group within the genus Bradyrhizobium. To verify their taxonomic status, these strains were further characterized using a polyphasic approach. All strains possessed identical 16S rRNA gene sequences that were 99.79 % similar to the closest relative, Bradyrhizobium liaoningense LMG 18230T. Phylogenetic analysis of concatenated atpD, glnII, recA, gyrB, rpoB and dnaK genes divided the 16 strains into three multilocus sequence types that were placed in a highly supported lineage distinct from named species of the genus Bradyrhizobium consistent with results of DNA–DNA hybridization. Based on analysis of symbiosis gene sequences (nodC and nifH), all novel strains were placed in a phylogenetic group with five species of the genus Bradyrhizobium that nodulate soybeans. The combination of phenotypic characteristics from several tests including carbon and nitrogen source utilization and antibiotic resistance could be used to differentiate representative strains from recognized species of the genus Bradyrhizobium. Novel strain OO99T elicits effective nodules on Glycine max, Glycine soja and Macroptilium atropurpureum, partially effective nodules on Desmodium canadense and Vigna unguiculata, and ineffective nodules on Amphicarpaea bracteata and Phaseolus vulgaris. Based on the data presented, we conclude that our strains represent a novel species for which the name Bradyrhizobium ottawaense sp. nov. is proposed, with OO99T ( = LMG 26739T = HAMBI 3284T) as the type strain. The DNA G+C content is 62.6 mol%. PMID:24969302

  8. Bradyrhizobium subterraneum sp. nov., a symbiotic nitrogen-fixing bacterium from root nodules of groundnuts.

    Science.gov (United States)

    Grönemeyer, Jann Lasse; Chimwamurombe, Percy; Reinhold-Hurek, Barbara

    2015-10-01

    Seven strains of symbiotic bacteria from root nodules of local races of Bambara groundnut (Vigna subterranea) and peanuts (Arachis hypogaea) grown on subsistence farmers' fields in the Kavango region, Namibia, were previously characterized and identified as a novel group within the genus Bradyrhizobium. To corroborate their taxonomic status, these strains were further characterized using a polyphasic approach. All strains possessed identical 16S rRNA gene sequences with Bradyrhizobium yuanmingense CCBAU 10071T being the most closely related type strain in the 16S rRNA gene phylogenetic analysis, and Bradyrhizobium daqingense CCBAU 15774T in the ITS sequence analysis. Phylogenetic analysis of concatenated glnII-recA-rpoB-dnaK placed the strains in a highly supported lineage distinct from named species of the genus Bradyrhizobium, most closely related to Bradyrhizobium yuanmingense CCBAU 10071T. The species status was validated by results of DNA–DNA hybridization. Phylogenetic analysis of nifH genes placed the novel strains in a group with nifH of ‘Bradyrhizobium arachidis’ CCBAU 051107 that also nodulates peanuts. The combination of phenotypic characteristics from several tests including carbon source utilization and antibiotic resistance could be used to differentiate representative strains from recognized species of the genus Bradyrhizobium. Novel strain 58 2-1T induced effective nodules on V. subterranea, Vigna unguiculata and A. hypogaea, and some strains on Lablab purpureus. Based on the data presented, we conclude that our strains represent a novel species for which the name Bradyrhizobium subterraneum sp. nov. is proposed, with 58 2-1T [ = DSM 100298T = LMG 28792T = NTCCM0016T (Windhoek)] as the type strain. The DNA G+C content of strain 58 2-1T was 64.7 mol% (T m).

  9. The reduced genomes of Parcubacteria (OD1) contain signatures of a symbiotic lifestyle

    Energy Technology Data Exchange (ETDEWEB)

    Nelson, William C.; Stegen, James C.

    2015-07-21

    Candidate phylum OD1 bacteria (also referred to as Parcubacteria) have been identified in broad range of anoxic environments through community survey analysis. Although none of these species have been isolated in the laboratory, several genome sequences have been reconstructed from metagenomic sequence data and single-cell sequencing. The organisms have small (generally <1 Mb) genomes with severely reduced metabolic capabilities. We have reconstructed 8 partial to near-complete OD1 genomes from oxic groundwater samples, and compared them against existing genomic data. The conserved core gene set comprises 202 genes, or ~28% of the genomic complement. ‘Housekeeping’ genes and genes for biosynthesis of peptidoglycan and Type IV pilus production are conserved. Gene sets for biosynthesis of cofactors, amino acids, nucleotides and fatty acids are absent entirely or greatly reduced. The only aspects of energy metabolism conserved are the non-oxidative branch of the pentose-phosphate shunt and central glycolysis. These organisms also lack some activities conserved in almost all other known bacterial genomes, including signal recognition particle, pseudouridine synthase A, and FAD synthase. Pan-genome analysis indicates a broad genotypic diversity and perhaps a highly fluid gene complement, indicating historical adaptation to a wide range of growth environments and a high degree of specialization. The genomes were examined for signatures suggesting either a free-living, streamlined lifestyle or a symbiotic lifestyle. The lack of biosynthetic capabilities and DNA repair, along with the presence of potential attachment and adhesion proteins suggest the Parcubacteria are ectosymbionts or parasites of other organisms. The wide diversity of genes that potentially mediate cell-cell contact suggests a broad range of partner/prey organisms across the phylum.

  10. Transfer of DNA from Bacteria to Eukaryotes

    Directory of Open Access Journals (Sweden)

    Benoît Lacroix

    2016-07-01

    Full Text Available Historically, the members of the Agrobacterium genus have been considered the only bacterial species naturally able to transfer and integrate DNA into the genomes of their eukaryotic hosts. Yet, increasing evidence suggests that this ability to genetically transform eukaryotic host cells might be more widespread in the bacterial world. Indeed, analyses of accumulating genomic data reveal cases of horizontal gene transfer from bacteria to eukaryotes and suggest that it represents a significant force in adaptive evolution of eukaryotic species. Specifically, recent reports indicate that bacteria other than Agrobacterium, such as Bartonella henselae (a zoonotic pathogen, Rhizobium etli (a plant-symbiotic bacterium related to Agrobacterium, or even Escherichia coli, have the ability to genetically transform their host cells under laboratory conditions. This DNA transfer relies on type IV secretion systems (T4SSs, the molecular machines that transport macromolecules during conjugative plasmid transfer and also during transport of proteins and/or DNA to the eukaryotic recipient cells. In this review article, we explore the extent of possible transfer of genetic information from bacteria to eukaryotic cells as well as the evolutionary implications and potential applications of this transfer.

  11. ESTs analysis reveals putative genes involved in symbiotic seed germination in Dendrobium officinale.

    Directory of Open Access Journals (Sweden)

    Ming-Ming Zhao

    Full Text Available Dendrobiumofficinale (Orchidaceae is one of the world's most endangered plants with great medicinal value. In nature, D. officinale seeds must establish symbiotic relationships with fungi to germinate. However, the molecular events involved in the interaction between fungus and plant during this process are poorly understood. To isolate the genes involved in symbiotic germination, a suppression subtractive hybridization (SSH cDNA library of symbiotically germinated D. officinale seeds was constructed. From this library, 1437 expressed sequence tags (ESTs were clustered to 1074 Unigenes (including 902 singletons and 172 contigs, which were searched against the NCBI non-redundant (NR protein database (E-value cutoff, e(-5. Based on sequence similarity with known proteins, 579 differentially expressed genes in D. officinale were identified and classified into different functional categories by Gene Ontology (GO, Clusters of orthologous Groups of proteins (COGs and Kyoto Encyclopedia of Genes and Genomes (KEGG pathways. The expression levels of 15 selected genes emblematic of symbiotic germination were confirmed via real-time quantitative PCR. These genes were classified into various categories, including defense and stress response, metabolism, transcriptional regulation, transport process and signal transduction pathways. All transcripts were upregulated in the symbiotically germinated seeds (SGS. The functions of these genes in symbiotic germination were predicted. Furthermore, two fungus-induced calcium-dependent protein kinases (CDPKs, which were upregulated 6.76- and 26.69-fold in SGS compared with un-germinated seeds (UGS, were cloned from D. officinale and characterized for the first time. This study provides the first global overview of genes putatively involved in D. officinale symbiotic seed germination and provides a foundation for further functional research regarding symbiotic relationships in orchids.

  12. Three Replicons of Rhizobium sp. Strain NGR234 Harbor Symbiotic Gene Sequences

    Science.gov (United States)

    Flores, Margarita; Mavingui, Patrick; Girard, Lourdes; Perret, Xavier; Broughton, William J.; Martínez-Romero, Esperanza; Dávila, Guillermo; Palacios, Rafael

    1998-01-01

    Rhizobium sp. strain NGR234 contains three replicons: the symbiotic plasmid or pNGR234a, a megaplasmid (pNGR234b), and the chromosome. Symbiotic gene sequences not present in pNGR234a were analyzed by hybridization. DNA sequences homologous to the genes fixLJKNOPQGHIS were found on the chromosome, while sequences homologous to nodPQ and exoBDFLK were found on pNGR234b. PMID:9811668

  13. Optical Manipulation of Symbiotic Chlorella in Paramecium Bursaria Using a Fiber Axicon Microlens

    International Nuclear Information System (INIS)

    Taguchi, K; Hirota, S; Nakayama, H; Kunugihara, D; Mihara, Y

    2012-01-01

    In this paper, chemically etched axicon fiber was proposed for laser trapping of symbiotic chlorella from paramecium bursaria. We fabricated axicon micro lenses on a single-mode bare optical fiber by selective chemical etching technique. The laser beam from fiber axicon microlens was strongly focused and optical forces were sufficient to move a symbiotic chlorella. From experimental results, it was found that our proposed fiber axicon microlens was a promising tool for cell trapping without physical contact.

  14. Optical Manipulation of Symbiotic Chlorella in Paramecium Bursaria Using a Fiber Axicon Microlens

    Science.gov (United States)

    Taguchi, K.; Hirota, S.; Nakayama, H.; Kunugihara, D.; Mihara, Y.

    2012-03-01

    In this paper, chemically etched axicon fiber was proposed for laser trapping of symbiotic chlorella from paramecium bursaria. We fabricated axicon micro lenses on a single-mode bare optical fiber by selective chemical etching technique. The laser beam from fiber axicon microlens was strongly focused and optical forces were sufficient to move a symbiotic chlorella. From experimental results, it was found that our proposed fiber axicon microlens was a promising tool for cell trapping without physical contact.

  15. Host Preference between Symbiotic and Aposymbiotic Aphis fabae, by the Aphid Parasitoid, Lysiphlebus ambiguus

    Science.gov (United States)

    Cheng, Rui-Xia; Meng, Ling; Mills, Nickolas J; Li, Baoping

    2011-01-01

    Few empirical studies have directly explored the association between Buchnera aphidicola (Enterobacteriales: Enterobacteriaceae), the primary endosymbiont of aphids, and the life history strategies of aphid parasitoids. A series of paired-choice experiments were conducted to explore the preference of the parasitoid Lysiphlebus ambiguus Halliday (Hymenoptera: Aphididae) for symbiotic and aposymbiotic Aphis fabae Scopoli (Hemiptera: Aphididae) and the suitability of these hosts for parasitoid development. When given a choice between symbiotic and aposymbiotic aphids of the same instar, the parasitoid significantly preferred symbiotic over aposymbiotic aphids only during the later instars (L4 and adult). The suitability of aposymbiotic aphids for parasitoid development was equal to that of symbiotic aphids in terms of survivorship and sex ratio, but was significantly lower than that of symbiotic aphids for L4 and adult instars in development rate and/or female adult size. When given a choice between similar-sized symbiotic L2 and aposymbiotic L4 aphids, the parasitoid preferred the former. No significant differences in preference or host suitability were demonstrated when the parasitoid was given a choice between different instars of aposymbiotic aphids. While parasitoid lifetime fecundity increased with aphid instar at the time of oviposition, there was no significant influence of previous development from symbiotic versus aposymbiotic aphids. These results suggest that while L. ambiguus can discriminate between symbiotic and aposymbiotic A. fabae during later instars and when the aphids are of a similar size, the primary endosymbiont is not needed for successful parasitoid development; and its absence only compromises parasitoid growth reared from later instar aposymbiotic host. PMID:21870967

  16. Antimicrobial effects of hops (Humulus lupulus) beta-acid on the growth and ammonia production of caprine ruminal hyper-ammonia-producing bacteria

    Science.gov (United States)

    Goats and other ruminants require the symbiotic microbes that live in the rumen to digest fiberous plant tissues. However, some rumen microbes impede animal health and performance. The hyper-ammonia-producing bacteria (HAB) catabolize nutitionally important amino acids, and produce ammonia (NH3). ...

  17. Plant densities and modulation of symbiotic nitrogen fixation in soybean

    Directory of Open Access Journals (Sweden)

    Marcos Javier de Luca

    2014-06-01

    Full Text Available Soybean nitrogen (N demands can be supplied to a large extent via biological nitrogen fixation, but the mechanisms of source/sink regulating photosynthesis/nitrogen fixation in high yielding cultivars and current crop management arrangements need to be investigated. We investigated the modulation of symbiotic nitrogen fixation in soybean [Glycine max (L. Merrill] at different plant densities. A field trial was performed in southern Brazil with six treatments, including non-inoculated controls without and with N-fertilizer, both at a density of 320,000 plants ha−1, and plants inoculated with Bradyrhizobium elkanii at four densities, ranging from 40,000 to 320,000 plants ha−1. Differences in nodulation, biomass production, N accumulation and partition were observed at stage R5, but not at stage V4, indicating that quantitative and qualitative factors (such as sunlight infrared/red ratio assume increasing importance during the later stages of plant growth. Decreases in density in the inoculated treatments stimulated photosynthesis and nitrogen fixation per plant. Similar yields were obtained at the different plant densities, with decreases only at the very low density level of 40,000 plants ha−1, which was also the only treatment to show differences in seed protein and oil contents. Results confirm a fine tuning of the mechanisms of source/sink, photosynthesis/nitrogen fixation under lower plant densities. Higher photosynthesis and nitrogen fixation rates are capable of sustaining increased plant growth.

  18. A Survey of Symbiotic Stars in the SMC

    Science.gov (United States)

    Gomes, S.; Akras, S.; Goncalves, R. D.; Boffin, H.; Guzman-Ramirez, L.

    2016-06-01

    Symbiotic systems (SySt) are interacting binary systems with a cool giant star and a hot star, generally a white dwarf. These systems are considered as potential candidates for type Ia supernova (SN Ia) progenitors. For verifying this hypothesis the total number of these systems has to be compared with the SN Ia rate in a galaxy to probe the connection between SySt and SNe Ia. We have started a systematic survey of SySt in the Small Magellanic Cloud (SMC) via the detection of the O VI λ6825 Raman scattered line, commonly observed in SySt. From September to December 2015, eleven 6.8x6.8 arcminute fields of the SMC were observed (one of them centered on a known SySt - SMC 3), by using FORS2 (FOcal Reducer and Spectrograph) at the Very Large Telescope (VLT). From the preliminary analysis of these data we were able to recover the known SySt as well as to identify 18 new O VI Raman scattered emitters. Seven out of the 18 candidates have 2MASS data, which allow us to plot them together with 19 IPHAS Galactic disk SySt and the 8 know SySt in the SMC in the J-H vs. H-Ks diagnostic diagram.

  19. The symbiotic intestinal ciliates and the evolution of their hosts.

    Science.gov (United States)

    Moon-van der Staay, Seung Yeo; van der Staay, Georg W M; Michalowski, Tadeusz; Jouany, Jean-Pierre; Pristas, Peter; Javorský, Peter; Kišidayová, Svetlana; Varadyova, Zora; McEwan, Neil R; Newbold, C Jamie; van Alen, Theo; de Graaf, Rob; Schmid, Markus; Huynen, Martijn A; Hackstein, Johannes H P

    2014-04-01

    The evolution of sophisticated differentiations of the gastro-intestinal tract enabled herbivorous mammals to digest dietary cellulose and hemicellulose with the aid of a complex anaerobic microbiota. Distinctive symbiotic ciliates, which are unique to this habitat, are the largest representatives of this microbial community. Analyses of a total of 484 different 18S rRNA genes show that extremely complex, but related ciliate communities can occur in the rumen of cattle, sheep, goats and red deer (301 sequences). The communities in the hindgut of equids (Equus caballus, Equus quagga), and elephants (Elephas maximus, Loxodonta africanus; 162 sequences), which are clearly distinct from the ruminant ciliate biota, exhibit a much higher diversity than anticipated on the basis of their morphology. All these ciliates from the gastro-intestinal tract constitute a monophyletic group, which consists of two major taxa, i.e. Vestibuliferida and Entodiniomorphida. The ciliates from the evolutionarily older hindgut fermenters exhibit a clustering that is specific for higher taxa of their hosts, as extant species of horse and zebra on the one hand, and Africa and Indian elephant on the other hand, share related ciliates. The evolutionary younger ruminants altogether share the various entodiniomorphs and the vestibuliferids from ruminants. Copyright © 2014 Elsevier GmbH. All rights reserved.

  20. LES ARM Symbiotic Simulation and Observation (LASSO) Implementation Strategy

    Energy Technology Data Exchange (ETDEWEB)

    Gustafson Jr., WI [Pacific Northwest National Laboratory; Vogelmann, AM [Brookhaven National Laboratory

    2015-09-01

    This document illustrates the design of the Large-Eddy Simulation (LES) ARM Symbiotic Simulation and Observation (LASSO) workflow to provide a routine, high-resolution modeling capability to augment the U.S. Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Climate Research Facility’s high-density observations. LASSO will create a powerful new capability for furthering ARM’s mission to advance understanding of cloud, radiation, aerosol, and land-surface processes. The combined observational and modeling elements will enable a new level of scientific inquiry by connecting processes and context to observations and providing needed statistics for details that cannot be measured. The result will be improved process understanding that facilitates concomitant improvements in climate model parameterizations. The initial LASSO implementation will be for ARM’s Southern Great Plains site in Oklahoma and will focus on shallow convection, which is poorly simulated by climate models due in part to clouds’ typically small spatial scale compared to model grid spacing, and because the convection involves complicated interactions of microphysical and boundary layer processes.

  1. DAILY BUDGETS OF PHOTOSYNTHETICALLY FIXED CARBON IN SYMBIOTIC ZOANTHIDS.

    Science.gov (United States)

    Steen, R Grant; Muscatine, L

    1984-10-01

    We tested the hypothesis that some zoanthids are able to meet a portion of their daily respiratory carbon requirement with photosynthetic carbon from symbiotic algal cells (= zooxanthellae). A daily budget was constructed for carbon (C) photosynthetically fixed by zooxanthellae of the Bermuda zoanthids Zoanthus sociatus and Palythoa variabilis. Zooxanthellae have an average net photosynthetic C fixation of 7.48 and 15.56 µgC·polyp -1 ·day -1 for Z. sociatus and P. variabilis respectively. The C-specific growth rate (µ c ) was 0.215·day -1 for Z. sociatus and 0.152·day -1 for P. variabilis. The specific growth rate (µ) of zooxanthellae in the zoanthids was measured to be 0.011 and 0.017·day -1 for Z. sociatus and P. variabilis zooxanthellae respectively. Z. sociatus zooxanthellae translocated 95.1% of the C assimilated in photosynthesis, while P. variabilis zooxanthellae translocated 88.8% of their fixed C. As the animal tissue of a polyp of Z. sociatus required 14.75 µgC·day -1 for respiration, and one of P. variabiis required 105.54 µgC·day -1 , the contribution of zooxanthellae to animal respiration (CZAR) was 48.2% for Z. sociatus and 13.1% for P. variabilis.

  2. SYMBIOTIC STARS IN X-RAYS. III. SUZAKU OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Nuñez, N. E. [Instituto de Ciencias Astronómicas de la Tierra y del Espacio (ICATE-UNSJ, CONICET), Av. España (S) 1512, J5402DSP, San Juan (Argentina); Nelson, T. [Minnesota Institute for Astrophysics, University of Minnesota, Minneapolis, MN, 55455 (United States); Mukai, K. [CRESST and X-ray Astrophysics Laboratory, (NASA/GSFC), Greenbelt, MD 20 771, USA. (United States); Sokoloski, J. L. [Columbia Astrophysics Lab, 550 W120th St., 1027 Pupin Hall, MC 5247 Columbia University, 10027, New York (United States); Luna, G. J. M., E-mail: nnunez@icate-conicet.gov.ar [Instituto de Astronomía y Física del Espacio (IAFE, CONICET-UBA), Av. Inte. Güiraldes 2620, C1428ZAA, Buenos Aires (Argentina)

    2016-06-10

    We describe the X-ray emission as observed by Suzaku from five symbiotic stars that we selected for deep Suzaku observations after their initial detection with ROSAT, ASCA , and Swift . We find that the X-ray spectra of all five sources can be adequately fit with absorbed optically thin thermal plasma models, with either single- or multi-temperature plasmas. These models are compatible with the X-ray emission originating in the boundary layer between an accretion disk and a white dwarf. The high plasma temperatures of kT > 3 keV for all five targets were greater than expected for colliding winds. Based on these high temperatures as well as previous measurements of UV variability and UV luminosity and the large amplitude of X-ray flickering in 4 Dra, we conclude that all five sources are accretion-powered through predominantly optically thick boundary layers. Our X-ray data allow us to observe a small optically thin portion of the emission from these boundary layers. Given the time between previous observations and these observations, we find that the intrinsic X-ray flux and the intervening absorbing column can vary by factors of three or more on a timescale of years. However, the location of the absorber and the relationship between changes in accretion rate and absorption are still elusive.

  3. Journalists and public health professionals: challenges of a symbiotic relationship.

    Science.gov (United States)

    Lubens, Pauline

    2015-02-01

    Journalists and health professionals share a symbiotic relationship during a disease outbreak as both professions play an important role in informing the public's perceptions and the decisions of policy makers. Although critics in the United States have focused on US reporters and media outlets whose coverage has been sensationalist and alarmist, the discussion in this article is based on the ideal--gold standard--for US journalists. Journalists perform three primary functions during times of health crises: disseminating accurate information to the public, medical professionals, and policy makers; acting as the go-between for the public and decision makers and health and science experts; and monitoring the performance of institutions responsible for the public health response. A journalist's goal is to responsibly inform the public in order to optimize the public health goals of prevention while minimizing panic. The struggle to strike a balance between humanizing a story and protecting the dignity of patients while also capturing the severity of an epidemic is harder in the era of the 24-7 news cycle. Journalists grapple with dueling pressures: confirming that their information is correct while meeting the demand for rapid updates. Just as health care professionals triage patients, journalists triage information. The challenge going forward will be how to get ahead of the story from the onset, racing against the pace of digital dissemination of misinformation by continuing to refine the media-science relationship.

  4. Evolution of the symbiotic binary system AG Dranconis

    Science.gov (United States)

    Mikolajewska, Joanna; Kenyon, Scott J; Mikolajewski, Maciej; Garcia, Michael R.; Polidan, Ronald S.

    1995-01-01

    We present an analysis of new and archival photometric and spectroscopic observations of the symbiotic star AG Draconis. This binary has undergone several 1 - 3 mag optical and ultraviolet eruptions during the past 15 years. Our combination of optical and ultraviolet spectroscopic data allow a more complete analysis of this system than in previous papers. AG Dra is composed of a K-type bright giant M(sub g) approximately 1.5 solar mass) and a hot, compact star M(sub h approximatelly 0.4 - 0.6 solar mass) embedded in a dense, low metallicity nebula. The hot component undergoes occasional thermonuclear runaways that produce 2 - 3 mag optical/ultraviolet eruptions. During these eruptions, the hot component develops a low velocity wind that quenches x-ray emission from the underlying hot white dwarf. The photoionized nebula changes its volume by a factor of 5 throughout an eruptin cycle. The K bright giant occults low ionization emission lines during superior conjunctions at all outburst phases but does not occult high ionization lines in outburst (and perhaps quiescence). This geometry and the component masses suggest a system inclination of i approximately 30 deg - 45 deg.

  5. Major fungal lineages are derived from lichen symbiotic ancestors.

    Science.gov (United States)

    Lutzoni, F; Pagel, M; Reeb, V

    2001-06-21

    About one-fifth of all known extant fungal species form obligate symbiotic associations with green algae, cyanobacteria or with both photobionts. These symbioses, known as lichens, are one way for fungi to meet their requirement for carbohydrates. Lichens are widely believed to have arisen independently on several occasions, accounting for the high diversity and mixed occurrence of lichenized and non-lichenized (42 and 58%, respectively) fungal species within the Ascomycota. Depending on the taxonomic classification chosen, 15-18 orders of the Ascomycota include lichen-forming taxa, and 8-11 of these orders (representing about 60% of the Ascomycota species) contain both lichenized and non-lichenized species. Here we report a phylogenetic comparative analysis of the Ascomycota, a phylum that includes greater than 98% of known lichenized fungal species. Using a Bayesian phylogenetic tree sampling methodology combined with a statistical model of trait evolution, we take into account uncertainty about the phylogenetic tree and ancestral state reconstructions. Our results show that lichens evolved earlier than believed, and that gains of lichenization have been infrequent during Ascomycota evolution, but have been followed by multiple independent losses of the lichen symbiosis. As a consequence, major Ascomycota lineages of exclusively non-lichen-forming species are derived from lichen-forming ancestors. These species include taxa with important benefits and detriments to humans, such as Penicillium and Aspergillus.

  6. Identification of Metabolically Active Bacteria in the Gut of the Generalist Spodoptera littoralis via DNA Stable Isotope Probing Using 13C-Glucose

    OpenAIRE

    Shao, Yongqi; Arias-Cordero, Erika M; Boland, Wilhelm

    2013-01-01

    Guts of most insects are inhabited by complex communities of symbiotic nonpathogenic bacteria. Within such microbial communities it is possible to identify commensal or mutualistic bacteria species. The latter ones, have been observed to serve multiple functions to the insect, i.e. helping in insect reproduction1, boosting the immune response2, pheromone production3, as well as nutrition, including the synthesis of essential amino acids4, among others.    

  7. Significance and Roles of Proteus spp. Bacteria in Natural Environments.

    Science.gov (United States)

    Drzewiecka, Dominika

    2016-11-01

    Proteus spp. bacteria were first described in 1885 by Gustav Hauser, who had revealed their feature of intensive swarming growth. Currently, the genus is divided into Proteus mirabilis, Proteus vulgaris, Proteus penneri, Proteus hauseri, and three unnamed genomospecies 4, 5, and 6 and consists of 80 O-antigenic serogroups. The bacteria are known to be human opportunistic pathogens, isolated from urine, wounds, and other clinical sources. It is postulated that intestines are a reservoir of these proteolytic organisms. Many wild and domestic animals may be hosts of Proteus spp. bacteria, which are commonly known to play a role of parasites or commensals. However, interesting examples of their symbiotic relationships with higher organisms have also been described. Proteus spp. bacteria present in soil or water habitats are often regarded as indicators of fecal pollution, posing a threat of poisoning when the contaminated water or seafood is consumed. The health risk may also be connected with drug-resistant strains sourcing from intestines. Positive aspects of the bacteria presence in water and soil are connected with exceptional features displayed by autochthonic Proteus spp. strains detected in these environments. These rods acquire various metabolic abilities allowing their adaptation to different environmental conditions, such as high concentrations of heavy metals or toxic substances, which may be exploited as sources of energy and nutrition by the bacteria. The Proteus spp. abilities to tolerate or utilize polluting compounds as well as promote plant growth provide a possibility of employing these microorganisms in bioremediation and environmental protection.

  8. Bacteria associated with the bleached and cave coral Oculina patagonica.

    Science.gov (United States)

    Koren, Omry; Rosenberg, Eugene

    2008-04-01

    The relative abundance of bacteria in the mucus and tissues of Oculina patagonica taken from bleached and cave (azooxanthellae) corals was determined by analyses of the 16S rRNA genes from cloned libraries of extracted DNA and from isolated colonies. The results were compared to previously published data on healthy O. patagonica. The bacterial community of bleached, cave, and healthy corals were completely different from each other. A tight cluster (>99.5% identity) of bacteria, showing 100% identity to Acinetobacter species, dominated bleached corals, comprising 25% of the 316 clones sequenced. The dominant bacterial cluster found in cave corals, representing 29% of the 97 clones sequenced, showed 98% identity to an uncultured bacterium from the Great Barrier Reef. Vibrio splendidus was the most dominant species in healthy O. patagonica. The culturable bacteria represented 0.1-1.0% of the total bacteria (SYBR Gold staining) of the corals. The most abundant culturable bacteria in bleached, cave, and healthy corals were clusters that most closely matched Microbulbifer sp., an alpha-proteobacterium previously isolated from healthy corals and an alpha-protobacterium (AB026194), respectively. Three generalizations emerge from this study on O. patagonica: (1) More bacteria are associated with coral tissue than mucus; (2) tissue and mucus populations are different; (3) bacterial populations associated with corals change dramatically when corals lack their symbiotic zooxanthellae, either as a result of the bleaching disease or when growing in the absence of light.

  9. Operation optimization of a photo-sequencing batch reactor for wastewater treatment: Study on influencing factors and impact on symbiotic microbial ecology.

    Science.gov (United States)

    Ye, Jianfeng; Liang, Junyu; Wang, Liang; Markou, Giorgos; Jia, Qilong

    2018-03-01

    Wastewater treatment technology with better energy efficiency and recyclability is in urgent demand. Photo-Sequencing batch reactor (SBR), which introduces microalgae into conventional SBR, is considered to have more potential for resource recycling. In this study, a photo-SBR was evaluated through the manipulation of several key operational parameters, i.e., aeration strength, light supply intensity and time per cycle, and solid retention time (SRT). The algal-bacterial symbiotic system had the potential of removing COD, NH 4 + -N and TN with limited aeration, representing the advantage of energy-saving by low aeration requirement. Maintaining appropriate proportion of microalgae in the symbiotic system is critical for good system performance. Introducing microalgae into conventional SBR has obvious impact on the original microbial ecology. When the concentration of microalgae is too high (>4.60 mg Chl/L), the inhibition on certain phyla of bacteria, e.g., Bacteroidetes and Actinobacteria, would become prominent and not conducive to the stable operation. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. The Symbiotic Relationship between Scientific Workflow and Provenance (Invited)

    Science.gov (United States)

    Stephan, E.

    2010-12-01

    The purpose of this presentation is to describe the symbiotic nature of scientific workflows and provenance. We will also discuss the current trends and real world challenges facing these two distinct research areas. Although motivated differently, the needs of the international science communities are the glue that binds this relationship together. Understanding and articulating the science drivers to these communities is paramount as these technologies evolve and mature. Originally conceived for managing business processes, workflows are now becoming invaluable assets in both computational and experimental sciences. These reconfigurable, automated systems provide essential technology to perform complex analyses by coupling together geographically distributed disparate data sources and applications. As a result, workflows are capable of higher throughput in a shorter amount of time than performing the steps manually. Today many different workflow products exist; these could include Kepler and Taverna or similar products like MeDICI, developed at PNNL, that are standardized on the Business Process Execution Language (BPEL). Provenance, originating from the French term Provenir “to come from”, is used to describe the curation process of artwork as art is passed from owner to owner. The concept of provenance was adopted by digital libraries as a means to track the lineage of documents while standards such as the DublinCore began to emerge. In recent years the systems science community has increasingly expressed the need to expand the concept of provenance to formally articulate the history of scientific data. Communities such as the International Provenance and Annotation Workshop (IPAW) have formalized a provenance data model. The Open Provenance Model, and the W3C is hosting a provenance incubator group featuring the Proof Markup Language. Although both workflows and provenance have risen from different communities and operate independently, their mutual

  11. Nutritional, eco-physiological and symbiotic characteristics of ...

    African Journals Online (AJOL)

    Characterization of root nodule bacteria is used for selecting and using them as inoculants to improve legume production. To this end, faba bean (Vicia faba L.) rhizobia were isolated from nodules collected from acidic soils of Central and Southern-Western parts of Ethiopia. A total of hundred rhizobial isolates were ...

  12. Stable and sporadic symbiotic communities of coral and algal holobionts

    NARCIS (Netherlands)

    Hester, E.R.; Barott, K.L.; Nulton, J.; Vermeij, M.J.A.; Rohwer, F.L.

    2016-01-01

    Coral and algal holobionts are assemblages of macroorganisms and microorganisms, including viruses, Bacteria, Archaea, protists and fungi. Despite a decade of research, it remains unclear whether these associations are spatial-temporally stable or species-specific. We hypothesized that conflicting

  13. Plant Genes Involved in Symbiotic Sinal Perception/Signal Transduction

    DEFF Research Database (Denmark)

    Binder, A; Soyano, T; Hayashi, H

    2014-01-01

    A host genetic programme that is initiated upon recognition of specific rhizobial Nod factors governs the symbiosis of legumes with nitrogen-fixing bacteria. This programme coordinates two major developmental processes that run in parallel in legume roots: de novo cortical cell division leading...

  14. Rhizobial peptidase HrrP cleaves host-encoded signaling peptides and mediates symbiotic compatibility.

    Science.gov (United States)

    Price, Paul A; Tanner, Houston R; Dillon, Brett A; Shabab, Mohammed; Walker, Graham C; Griffitts, Joel S

    2015-12-08

    Legume-rhizobium pairs are often observed that produce symbiotic root nodules but fail to fix nitrogen. Using the Sinorhizobium meliloti and Medicago truncatula symbiotic system, we previously described several naturally occurring accessory plasmids capable of disrupting the late stages of nodule development while enhancing bacterial proliferation within the nodule. We report here that host range restriction peptidase (hrrP), a gene found on one of these plasmids, is capable of conferring both these properties. hrrP encodes an M16A family metallopeptidase whose catalytic activity is required for these symbiotic effects. The ability of hrrP to suppress nitrogen fixation is conditioned upon the genotypes of both the host plant and the hrrP-expressing rhizobial strain, suggesting its involvement in symbiotic communication. Purified HrrP protein is capable of degrading a range of nodule-specific cysteine-rich (NCR) peptides encoded by M. truncatula. NCR peptides are crucial signals used by M. truncatula for inducing and maintaining rhizobial differentiation within nodules, as demonstrated in the accompanying article [Horváth B, et al. (2015) Proc Natl Acad Sci USA, 10.1073/pnas.1500777112]. The expression pattern of hrrP and its effects on rhizobial morphology are consistent with the NCR peptide cleavage model. This work points to a symbiotic dialogue involving a complex ensemble of host-derived signaling peptides and bacterial modifier enzymes capable of adjusting signal strength, sometimes with exploitative outcomes.

  15. Nutritional status and systemic inflammatory activity of colorectal patients on symbiotic supplementation.

    Science.gov (United States)

    de Oliveira, Ana Lívia; Aarestrup, Fernando Monteiro

    2012-01-01

    Nutritional depletion in patients with advanced colorectal cancer, even with adequate weight, may be associated with co-morbidity factors such as: reduction of immunity, increased rate of infections, impaired cicatrization and muscle weakness. Immunomodulating diets have recently been used as a nutritional approach to cancer patients. Prebiotics, probiotics and symbiotics (a mixture of the first two) have been studied. To assess the Nutritional Status and Systemic Inflammatory Activity of colorectal patients on symbiotic supplementation. It was a progressive longitudinal study in colorectal cancer patients. All patients underwent assessment of nutritional status and subsequent serological analysis, daily use of the symbiotic supplement, anthropometric and biochemical assessment every three months Besides anthropometric data, the following blood components were measured: C-reactive protein (CRP), carcino-embryonic antigen (CEA) and albumin. The mean CRP level at baseline, before symbiotic administration, was 11 mg/dL, with a reduction to below 6 mg/dL at the end of the study. There was a beneficial effect of symbiotic supplementation, because although albumin and CEA levels were stable during the study, there was a CRP reduction in meantime.

  16. Rotation of the Mass Donors in High-mass X-ray Binaries and Symbiotic Stars

    Directory of Open Access Journals (Sweden)

    K. Stoyanov

    2015-02-01

    Full Text Available Our aim is to investigate the tidal interaction in High-mass X-ray Binaries and Symbiotic stars in order to determine in which objects the rotation of the mass donors is synchronized or pseudosynchronized with the orbital motion of the compact companion. We find that the Be/X-ray binaries are not synchronized and the orbital periods of the systems are greater than the rotational periods of the mass donors. The giant and supergiant High-mass X-ray binaries and symbiotic stars are close to synchronization. We compare the rotation of mass donors in symbiotics with the projected rotational velocities of field giants and find that the M giants in S-type symbiotics rotate on average 1.5 times faster than the field M giants. We find that the projected rotational velocity of the red giant in symbiotic star MWC 560 is v sin i= 8.2±1.5 km.s−1, and estimate its rotational period to be Prot<>/sub = 144 - 306 days. Using the theoretical predictions of tidal interaction and pseudosynchronization, we estimate the orbital eccentricity e = 0.68 − 0.82.

  17. Interlaboratory comparison of real-time pcr protocols for quantification of general fecal indicator bacteria

    Science.gov (United States)

    Shanks, O.C.; Sivaganesan, M.; Peed, L.; Kelty, C.A.; Blackwood, A.D.; Greene, M.R.; Noble, R.T.; Bushon, R.N.; Stelzer, E.A.; Kinzelman, J.; Anan'Eva, T.; Sinigalliano, C.; Wanless, D.; Griffith, J.; Cao, Y.; Weisberg, S.; Harwood, V.J.; Staley, C.; Oshima, K.H.; Varma, M.; Haugland, R.A.

    2012-01-01

    The application of quantitative real-time PCR (qPCR) technologies for the rapid identification of fecal bacteria in environmental waters is being considered for use as a national water quality metric in the United States. The transition from research tool to a standardized protocol requires information on the reproducibility and sources of variation associated with qPCR methodology across laboratories. This study examines interlaboratory variability in the measurement of enterococci and Bacteroidales concentrations from standardized, spiked, and environmental sources of DNA using the Entero1a and GenBac3 qPCR methods, respectively. Comparisons are based on data generated from eight different research facilities. Special attention was placed on the influence of the DNA isolation step and effect of simplex and multiplex amplification approaches on interlaboratory variability. Results suggest that a crude lysate is sufficient for DNA isolation unless environmental samples contain substances that can inhibit qPCR amplification. No appreciable difference was observed between simplex and multiplex amplification approaches. Overall, interlaboratory variability levels remained low (<10% coefficient of variation) regardless of qPCR protocol. ?? 2011 American Chemical Society.

  18. Water quality and sources of fecal coliform bacteria in the Meduxnekeag River, Houlton, Maine

    Science.gov (United States)

    Culbertson, Charles W.; Huntington, Thomas G.; Stoeckel, Donald M.; Caldwell, James M.; O'Donnell, Cara

    2014-01-01

    In response to bacterial contamination in the Meduxnekeag River and the desire to manage the watershed to reduce contaminant sources, the Houlton Band of Maliseet Indians (HBMI) and the U.S. Geological Survey began a cooperative effort to establish a baseline of water-quality data that can be used in future studies and to indicate potential sources of nutrient and bacterial contamination. This study was conducted during the summer of 2005 in the Meduxnekeag River Basin near Houlton, Maine. Continuously recorded specific conductance can be a good indicator for water quality. Specific conductance increased downstream from the town of Houlton, between runoff events, and decreased sharply following major runoff events. Collections of discrete samples during the summer of 2005 indicated seasonal positive concentration-discharge relations for total phosphorus and total nitrogen; these results indicate that storm runoff may mobilize and transport these nutrients from the terrestrial environment to the river. Data collected by the HBMI on fecal coliform bacteria indicated that bacterial contamination enters the Meduxnekeag River from multiple paths including tributaries and surface drains (ditches) in developed areas in Houlton, Maine. The Houlton wastewater treatment discharge was not an important source of bacterial contamination. Bacteroidales-based tests for general fecal contamination (Bac32 marker) were predominantly positive in samples that had excessive fecal contamination as indicated by Enterococci density greater than 104 colony-forming units per 100 millilters. Of the 22 samples tested for Bacteroidales-based markers of human-associated fecal contamination (HF134 and HF183), 8 were positive. Of the 22 samples tested for Bacteroidales-based markers of ruminant-associated fecal contamination (CF128 and CF193), 7 were positive. Human fecal contamination was detected consistently at two sites (surface drains in urban areas in the town of Houlton) and occasionally

  19. Responses to Elevated c-di-GMP Levels in Mutualistic and Pathogenic Plant-Interacting Bacteria

    Science.gov (United States)

    Pérez-Mendoza, Daniel; Aragón, Isabel M.; Prada-Ramírez, Harold A.; Romero-Jiménez, Lorena; Ramos, Cayo; Gallegos, María-Trinidad; Sanjuán, Juan

    2014-01-01

    Despite a recent burst of research, knowledge on c-di-GMP signaling pathways remains largely fragmentary and molecular mechanisms of regulation and even c-di-GMP targets are yet unknown for most bacteria. Besides genomics or bioinformatics, accompanying alternative approaches are necessary to reveal c-di-GMP regulation in bacteria with complex lifestyles. We have approached this study by artificially altering the c-di-GMP economy of diverse pathogenic and mutualistic plant-interacting bacteria and examining the effects on the interaction with their respective host plants. Phytopathogenic Pseudomonas and symbiotic Rhizobium strains with enhanced levels of intracellular c-di-GMP displayed common free-living responses: reduction of motility, increased production of extracellular polysaccharides and enhanced biofilm formation. Regarding the interaction with the host plants, P. savastanoi pv. savastanoi cells containing high c-di-GMP levels formed larger knots on olive plants which, however, displayed reduced necrosis. In contrast, development of disease symptoms in P. syringae-tomato or P. syringae-bean interactions did not seem significantly affected by high c-di-GMP. On the other hand, increasing c-di-GMP levels in symbiotic R. etli and R. leguminosarum strains favoured the early stages of the interaction since enhanced adhesion to plant roots, but decreased symbiotic efficiency as plant growth and nitrogen contents were reduced. Our results remark the importance of c-di-GMP economy for plant-interacting bacteria and show the usefulness of our approach to reveal particular stages during plant-bacteria associations which are sensitive to changes in c-di-GMP levels. PMID:24626229

  20. [Bioengineering of symbiotic systems: creation of new associative symbiosis with the use of lectins on the example of tobacco and colza].

    Science.gov (United States)

    Vershinina, Z P; Baĭmiev, An Kh; Blagova, D K; Kniazev, A V; Baĭmiev, Al Kh; Chemeris, A V

    2011-01-01

    "Barbate roots" in tobacco and colza transgenic on lectin gene were obtained with the use of a wild strain of Agrobacterium rhizogenes 15834 transformed with pCAMBIA1305.1 plasmid containing the full-size lectin gene (psl) from the Pisum sativum. Influence of expression oflectin gene on colonization oftransgenic roots with symbiont of pea (Rhizobium leguminosarum) was investigated. The number of adhered bacteria onto the roots transformed with lectin gene was 14-fold and 37-fold higher in comparison with the control; this confirms the interaction of R. leguminosarum with pea lectin at the surface of the transformed roots of tobacco and colza. The developed experimental approach, based on the simulation of recognition processes and early symbiotic interactions with lectins of pea plants, may, in perspective, be used for obtaining stable associations of economically valuable, nonsymbiotrophic plant species with rhizobia.

  1. Transcriptomic profiling of Burkholderia phymatum STM815, Cupriavidus taiwanensis LMG19424 and Rhizobium mesoamericanum STM3625 in response to Mimosa pudica root exudates illuminates the molecular basis of their nodulation competitiveness and symbiotic evolutionary history.

    Science.gov (United States)

    Klonowska, Agnieszka; Melkonian, Rémy; Miché, Lucie; Tisseyre, Pierre; Moulin, Lionel

    2018-01-30

    Rhizobial symbionts belong to the classes Alphaproteobacteria and Betaproteobacteria (called "alpha" and "beta"-rhizobia). Most knowledge on the genetic basis of symbiosis is based on model strains belonging to alpha-rhizobia. Mimosa pudica is a legume that offers an excellent opportunity to study the adaptation toward symbiotic nitrogen fixation in beta-rhizobia compared to alpha-rhizobia. In a previous study (Melkonian et al., Environ Microbiol 16:2099-111, 2014) we described the symbiotic competitiveness of M. pudica symbionts belonging to Burkholderia, Cupriavidus and Rhizobium species. In this article we present a comparative analysis of the transcriptomes (by RNAseq) of B. phymatum STM815 (BP), C. taiwanensis LMG19424 (CT) and R. mesoamericanum STM3625 (RM) in conditions mimicking the early steps of symbiosis (i.e. perception of root exudates). BP exhibited the strongest transcriptome shift both quantitatively and qualitatively, which mirrors its high competitiveness in the early steps of symbiosis and its ancient evolutionary history as a symbiont, while CT had a minimal response which correlates with its status as a younger symbiont (probably via acquisition of symbiotic genes from a Burkholderia ancestor) and RM had a typical response of Alphaproteobacterial rhizospheric bacteria. Interestingly, the upregulation of nodulation genes was the only common response among the three strains; the exception was an up-regulated gene encoding a putative fatty acid hydroxylase, which appears to be a novel symbiotic gene specific to Mimosa symbionts. The transcriptional response to root exudates was correlated to each strain nodulation competitiveness, with Burkholderia phymatum appearing as the best specialised symbiont of Mimosa pudica.

  2. The complex symbiotic relationships of bark beetles with microorganisms: a potential practical approach for biological control in forestry.

    Science.gov (United States)

    Popa, Valentin; Déziel, Eric; Lavallée, Robert; Bauce, Eric; Guertin, Claude

    2012-07-01

    Bark beetles, especially Dendroctonus species, are considered to be serious pests of the coniferous forests in North America. Bark beetle forest pests undergo population eruptions, causing region wide economic losses. In order to save forests, finding new and innovative environmentally friendly approaches in wood-boring insect pest management is more important than ever. Several biological control methods have been attempted over time to limit the damage and spreading of bark beetle epidemics. The use of entomopathogenic microorganisms against bark beetle populations is an attractive alternative tool for many biological control programmes in forestry. However, the effectiveness of these biological control agents is strongly affected by environmental factors, as well as by the susceptibility of the insect host. Bark beetle susceptibility to entomopathogens varies greatly between species. According to recent literature, bark beetles are engaged in symbiotic relationships with fungi and bacteria. These types of relationship are very complex and apparently involved in bark beetle defensive mechanisms against pathogens. The latest scientific discoveries in multipartite symbiosis have unravelled unexpected opportunities in bark beetle pest management, which are discussed in this article. Copyright © 2012 Society of Chemical Industry.

  3. Symbiotic nitrogen fixation in the alpine community of a lichen heath of the Northwestern Caucasus Region (the Teberda Reserve)

    Science.gov (United States)

    Makarov, M. I.; Malysheva, T. I.; Ermak, A. A.; Onipchenko, V. G.; Stepanov, A. L.; Menyailo, O. V.

    2011-12-01

    The symbiotic fixation of atmospheric nitrogen by leguminous plants in the alpine community of a lichen heath at the Teberda State Biosphere Reserve is well adapted to low soil temperature characteristic for the altitude of 2800 m a.s.l. For the determination of the N fixation by isotopic methods (the method of the natural 15N abundance and the method of isotopic 15N dilution), Trifolium polyphyllum was taken as the control plant. This plant was used as it does not form symbiosis with the nitrogen-fixing bacteria in the highlands of the Northern Caucasus Region. The contribution of the N fixation to the N nutrition of different leguminous plant species as determined by the natural 15N abundance method amounted to 28-73% at δ15N0 = 0‰ and 46-117% at δ15N0 = -1‰; for the determination of the N fixation by the method of the isotopic label's dilution, it was 34-97%. The best correlation of the results obtained by these two isotopic methods was observed for the natural fractionation of the N isotopes in the course of the N fixation in the range of -0.5 to -0.7‰. The determination of the nitrogenase activity of the roots by the acetylene method confirmed the absence of N fixation in T. polyphyllum and its different contribution to the N nutrition of different species of leguminous plants.

  4. Infrared spectroscopy of symbiotic stars and the nature of their cool components

    International Nuclear Information System (INIS)

    Kenyon, S.J.; Gallagher, J.S.

    1983-01-01

    We present low-resolution 2--4 μm spectroscopy of a small sample of symbiotic stars, in an effort to determine if the giant components of these systems fill their Roche Lobes. A [2.35]-[2.2] color index measures the strength of the CO absorption band and provides a useful discriminant of luminosity class among single M-type giants which separates normal giants from supergiants at the same spectral type. Although interpretation of symbiotic spectra is complicated somewhat by their binary nature, our results suggest the late-type components in these systems range from normal red giants to bright asymptotic giants. The possible presence of non-Roche Lobe filling, low-luminosity giants in some symbiotic stars cannot be understood within the framework of existing theories for these interesting objects, and thus may provide important information for understanding mass transfer in binary systems

  5. Diagnostic of the Symbiotic Stars Environment by Thomson, Raman and Rayleigh Scattering Processes

    Directory of Open Access Journals (Sweden)

    M. Sekeráš

    2015-02-01

    Full Text Available Symbiotic stars are long-period interacting binaries consisting of a cool giant as the donor star and a white dwarf as the acretor. Due to acretion of the material from the giant’s stellar wind, the white dwarf becomes very hot and luminous. The circumstellar material partially ionized by the hot star, represents an ideal medium for processes of scattering. To investigate the symbiotic nebula we modeled the wide wings of the resonance lines OVI λ1032 Å, λ1038 Å and HeII λ1640 Å emission line in the spectrum of AG Dra, broadened by Thomson scattering. On the other hand, Raman and Rayleigh scattering arise in the neutral part of the circumstellar matter around the giant and provide a powerful tool to probe e.g. the ionization structure of the symbiotic systems and distribution of the neutral hydrogen atoms in the giant’s wind.

  6. The diversity of citrus endophytic bacteria and their interactions with Xylella fastidiosa and host plants

    Directory of Open Access Journals (Sweden)

    João Lúcio Azevedo

    Full Text Available Abstract The bacterium Xylella fastidiosa is the causal agent of citrus variegated chlorosis (CVC and has been associated with important losses in commercial orchards of all sweet orange [Citrus sinensis (L.] cultivars. The development of this disease depends on the environmental conditions, including the endophytic microbial community associated with the host plant. Previous studies have shown that X. fastidiosa interacts with the endophytic community in xylem vessels as well as in the insect vector, resulting in a lower bacterial population and reduced CVC symptoms. The citrus endophytic bacterium Methylobacterium mesophilicum can trigger X. fastidiosa response in vitro, which results in reduced growth and induction of genes associated with energy production, stress, transport, and motility, indicating that X. fastidiosa has an adaptive response to M. mesophilicum. Although this response may result in reduced CVC symptoms, the colonization rate of the endophytic bacteria should be considered in studies that intend to use this endophyte to suppress CVC disease. Symbiotic control is a new strategy that uses symbiotic endophytes as biological control agents to antagonize or displace pathogens. Candidate endophytes for symbiotic control of CVC must occupy the xylem of host plants and attach to the precibarium of sharpshooter insects to access the pathogen. In the present review, we focus on interactions between endophytic bacteria from sweet orange plants and X. fastidiosa, especially those that may be candidates for control of CVC.

  7. The diversity of citrus endophytic bacteria and their interactions with Xylella fastidiosa and host plants

    Science.gov (United States)

    Azevedo, João Lúcio; Araújo, Welington Luiz; Lacava, Paulo Teixeira

    2016-01-01

    Abstract The bacterium Xylella fastidiosa is the causal agent of citrus variegated chlorosis (CVC) and has been associated with important losses in commercial orchards of all sweet orange [Citrus sinensis (L.)] cultivars. The development of this disease depends on the environmental conditions, including the endophytic microbial community associated with the host plant. Previous studies have shown that X. fastidiosa interacts with the endophytic community in xylem vessels as well as in the insect vector, resulting in a lower bacterial population and reduced CVC symptoms. The citrus endophytic bacterium Methylobacterium mesophilicum can trigger X. fastidiosa response in vitro, which results in reduced growth and induction of genes associated with energy production, stress, transport, and motility, indicating that X. fastidiosa has an adaptive response to M. mesophilicum. Although this response may result in reduced CVC symptoms, the colonization rate of the endophytic bacteria should be considered in studies that intend to use this endophyte to suppress CVC disease. Symbiotic control is a new strategy that uses symbiotic endophytes as biological control agents to antagonize or displace pathogens. Candidate endophytes for symbiotic control of CVC must occupy the xylem of host plants and attach to the precibarium of sharpshooter insects to access the pathogen. In the present review, we focus on interactions between endophytic bacteria from sweet orange plants and X. fastidiosa, especially those that may be candidates for control of CVC. PMID:27727362

  8. [Genetic characterization of wild leguminous nodular bacteria living in the South Urals].

    Science.gov (United States)

    Baĭmiev, An Kh; Ivanova, E S; Ptitsyn, K G; Belimov, A A; Safronova, V I; Baĭmiev, Al Kh

    2012-01-01

    Genetic diversity and phylogeny of rhizobia that nodulate 18 species of wild-growing bean plants of South Urals from 8 genera belonging to 4 tribes (Loteae, Genisteae, Galegeaev and Hedysareae) was studied. It was demonstrated that for the wild-growing plants of Galegeae and Hedysareae tribes symbiotic interaction with various strains of nodule bacteria that closely related to bacteria of Mesorhizobium sp. was typical of the plants of Genisteae tribe--to bacteria of Bradyrhizobium sp. In the nodules of Lortus ucrainicus from Loteae tribe we have found a rhizobium that is closely related to the bacteria of Mesorhizobium sp., and at Coronilla varia rhizobia strains obtained by us were close by sequence of a 16S pRNA gene to Rhizobium sp. In the nodules of some kinds of the investigated plants we found also minor species of a rhizobia, which structure is under the great influence of conditions of the host plant growth.

  9. Symbiotic Stars in X-rays. II. Faint Sources Detected with XMM-Newton and Chandra

    Science.gov (United States)

    Nunez, N. E.; Luna, G. J. M.; Pillitteri, I.; Mukai, K.

    2014-01-01

    We report the detection from four symbiotic stars that were not known to be X-ray sources. These four object show a ß-type X-ray spectrum, that is, their spectra can be modeled with an absorbed optically thin thermal emission with temperatures of a few million degrees. Photometric series obtained with the Optical Monitor on board XMM-Newton from V2416 Sgr and NSV 25735 support the proposed scenario where the X-ray emission is produced in a shock-heated region inside the symbiotic nebulae.

  10. Evaluation of the symbiotic nitrogen fixation in soybean by labelling of soil organic matter

    International Nuclear Information System (INIS)

    Ruschel, A.P.; Freitas, J.R. de; Vose, P.B.

    1982-01-01

    An experiment was carried out using the isotopic dilution method to evaluate symbiotic nitrogen fixation in soybean grown in soil labelled with 15 N enriched organic matter. Symbiotic N 2 -fixed was 71-76% of total N in the plant. Non nodulated soybean utilized 56-59% N from organic matter and 40% from soil. Roots of nodulated plants had lower NdN 2 than aereal plant parts. The advantage of using labelled organic matter as compared with 15 N-fertilizer addition in evaluating N 2 -fixation is discussed. (Author) [pt

  11. Spectroscopic observations of V443 Herculis - A symbiotic binary with a low mass white dwarf

    Science.gov (United States)

    Dobrzycka, Danuta; Kenyon, Scott J.; Mikolajewska, Joanna

    1993-01-01

    We present an analysis of new and existing photometric and spectroscopic observations of the symbiotic binary V443 Herculis. This binary system consists of a normal M5 giant and a hot compact star. These two objects have comparable luminosities: about 1500 solar for the M5 giant and about 1000 solar for the compact star. We identify three nebular regions in this binary: a small, highly ionized volume surrounding the hot component, a modestly ionized shell close to the red giant photosphere, and a less dense region of intermediate ionization encompassing both binary components. The system parameters for V443 Her suggest the hot component currently declines from a symbiotic nova eruption.

  12. Effects of humic acids on the growth of bacteria

    Science.gov (United States)

    Tikhonov, V. V.; Yakushev, A. V.; Zavgorodnyaya, Yu. A.; Byzov, B. A.; Demin, V. V.

    2010-03-01

    The influence of humic acids of different origins on the growth of bacterial cultures of different taxa isolated from the soil and the digestive tracts of earthworms ( Aporrectodea caliginosa)—habitats with contrasting conditions—was studied. More than half of the soil and intestinal isolates from the 170 tested strains grew on the humic acid of brown coal as the only carbon source. The specific growth rate of the bacteria isolated from the intestines of the earthworms was higher than that of the soil bacteria. The use of humic acids by intestinal bacteria confirms the possibility of symbiotic digestion by earthworms with the participation of bacterial symbionts. Humic acids at a concentration of 0.1 g/l stimulated the growth of the soil and intestinal bacteria strains (66 strains out of 161) on Czapek’s medium with glucose (1 g/l), probably, acting as a regulator of the cell metabolism. On the medium with the humic acid, the intestinal bacteria grew faster than the soil isolates did. The most active growth of the intestinal isolates was observed by Paenibacillus sp., Pseudomonas putida, Delftia acidovorans, Microbacterium terregens, and Aeromonas sp.; among the soil ones were the representatives of the Pseudomonas genus. A response of the bacteria to the influence of humic acids was shown at the strain level using the example of Pseudomonas representatives. The Flexom humin preparation stimulated the growth of the hydrocarbon-oxidizing Acinetobacter sp. bacteria. This effect can be used for creating a new compound with the elevated activity of bacteria that are destroyers of oil and oil products.

  13. Effect of free and symbiotic nitrogen fixing bacterial co-inoculation on seed and seedling of soybean seeds produced under deficit water condition

    Directory of Open Access Journals (Sweden)

    Hamed Hadi

    2016-04-01

    Full Text Available Effect of free and symbiotic nitrogen fixing bacteria on seed and seedling produced seeds under deficit irrigation was conducted in laboratory and field experiments in 2006. In laboratory of karaj’s Seed and Plant Research and Certificate Institute an experiment was conducted based on factorial in form of completely randomized design with four replications and in field’s of Islamic Azad University, Varamin Branch were split factorial in form of randomized completely block design with three replications. Treatments included water stress [Irrigation after 50 (Normal irrigation, 100 (Middle stress, 150 (Severe stress mm evaporation from pan class A], Cultivar [Manokin & Williams and SRF×T3 Line] and inoculation [Inoculation with Bradyrhizobium japonicum, Bradyrhizobium japonicum co-inoculated with Azotobacter chroococcum, No seed inoculation]. Results showed that drought stress decreased the uniformity and germination speed and seedling emergence. Bacteria increased leaf dry weight, stem dry weight, leaf area and seedling vigor index but had no effect on emergence. In irrigation levels inoculated treatments had higher seedling length, leaf, stem, seedling dry weight and seedling vigor. Severs stress seeds inoculated with Bradyrhizobium japonicum had higher root dry weight than control. Therefore in seeds which were produced under deficit irrigation conditions, bacteria increased seedlings vigor.

  14. Occurrence and Localization of Phycoerythrin in Symbiotic Nostoc of Cycas revoluta and in the Free-Living Isolated Nostoc 7422 1

    Science.gov (United States)

    Lindblad, Peter; Bergman, Birgitta

    1989-01-01

    The phycobiliprotein phycoerythrin was localized in symbiotic and free-living Nostoc of the cycad Cycas using immunocytochemistry. In symbiotic Nostoc, phycoerythrin was associated with the thylakoid membranes of vegetative cells and absent from heterocysts. Similar cellular/subcellular localization was observed between symbiotic Nostoc and the free-living Cycas isolate Nostoc 7422. Images Figure 1 Figure 2 Figure 3 PMID:16666621

  15. Bleach vs. Bacteria

    Science.gov (United States)

    ... Articles | Inside Life Science Home Page Bleach vs. Bacteria By Sharon Reynolds Posted April 2, 2014 Your ... hypochlorous acid to help kill invading microbes, including bacteria. Researchers funded by the National Institutes of Health ...

  16. Symbiotic Fungus of Marine Sponge Axinella sp. Producing Antibacterial Agent

    Science.gov (United States)

    Trianto, A.; Widyaningsih, S.; Radjasa, OK; Pribadi, R.

    2017-02-01

    The emerging of multidrug resistance pathogenic bacteria cause the treatment of the diseaseshave become ineffective. There for, invention of a new drug with novel mode of action is an essential for curing the disease caused by an MDR pathogen. Marine fungi is prolific source of bioactive compound that has not been well explored. This study aim to obtain the marine sponges-associated fungus that producing anti-MDR bacteria substaces. We collected the sponge from Riung water, NTT, Indonesia. The fungus was isolated with affixed method, followed with purification with streak method. The overlay and disk diffusion agar methods were applied for bioactivity test for the isolate and the extract, respectively. Molecular analysis was employed for identification of the isolate. The sponge was identified based on morphological and spicular analysis. The ovelay test showed that the isolate KN15-3 active against the MDR Staphylococcus aureus and Eschericia coli. The extract of the cultured KN15-3 was also inhibited the S. aureus and E. coli with inhibition zone 2.95 mm and 4.13 mm, respectively. Based on the molecular analysis, the fungus was identified as Aspergillus sydowii. While the sponge was identified as Axinella sp.

  17. IUE observations of the symbiotic star CH Cygni during an active phase

    International Nuclear Information System (INIS)

    Hack, M.

    1979-01-01

    The observations of CH Cygni reported here were made to determine whether a symbiotic star is a binary system composed of an M6 giant and a hot subdwarf, or whether it is a cooled star surrounded by a thick corona. (author)

  18. 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

  19. Biomimicry of symbiotic multi-species coevolution for discrete and continuous optimization in RFID networks

    Directory of Open Access Journals (Sweden)

    Na Lin

    2017-03-01

    Full Text Available In recent years, symbiosis as a rich source of potential engineering applications and computational model has attracted more and more attentions in the adaptive complex systems and evolution computing domains. Inspired by different symbiotic coevolution forms in nature, this paper proposed a series of multi-swarm particle swarm optimizers called PS2Os, which extend the single population particle swarm optimization (PSO algorithm to interacting multi-swarms model by constructing hierarchical interaction topologies and enhanced dynamical update equations. According to different symbiotic interrelationships, four versions of PS2O are initiated to mimic mutualism, commensalism, predation, and competition mechanism, respectively. In the experiments, with five benchmark problems, the proposed algorithms are proved to have considerable potential for solving complex optimization problems. The coevolutionary dynamics of symbiotic species in each PS2O version are also studied respectively to demonstrate the heterogeneity of different symbiotic interrelationships that effect on the algorithm’s performance. Then PS2O is used for solving the radio frequency identification (RFID network planning (RNP problem with a mixture of discrete and continuous variables. Simulation results show that the proposed algorithm outperforms the reference algorithms for planning RFID networks, in terms of optimization accuracy and computation robustness.

  20. Biomimicry of symbiotic multi-species coevolution for discrete and continuous optimization in RFID networks.

    Science.gov (United States)

    Lin, Na; Chen, Hanning; Jing, Shikai; Liu, Fang; Liang, Xiaodan

    2017-03-01

    In recent years, symbiosis as a rich source of potential engineering applications and computational model has attracted more and more attentions in the adaptive complex systems and evolution computing domains. Inspired by different symbiotic coevolution forms in nature, this paper proposed a series of multi-swarm particle swarm optimizers called PS 2 Os, which extend the single population particle swarm optimization (PSO) algorithm to interacting multi-swarms model by constructing hierarchical interaction topologies and enhanced dynamical update equations. According to different symbiotic interrelationships, four versions of PS 2 O are initiated to mimic mutualism, commensalism, predation, and competition mechanism, respectively. In the experiments, with five benchmark problems, the proposed algorithms are proved to have considerable potential for solving complex optimization problems. The coevolutionary dynamics of symbiotic species in each PS 2 O version are also studied respectively to demonstrate the heterogeneity of different symbiotic interrelationships that effect on the algorithm's performance. Then PS 2 O is used for solving the radio frequency identification (RFID) network planning (RNP) problem with a mixture of discrete and continuous variables. Simulation results show that the proposed algorithm outperforms the reference algorithms for planning RFID networks, in terms of optimization accuracy and computation robustness.

  1. Original article The Symbiotic Bond Questionnaire – theoretical background and psychometric qualities

    Directory of Open Access Journals (Sweden)

    Aleksandra Lewandowska-Walter

    2015-07-01

    Full Text Available Background The article describes the Symbiotic Bond Questionnaire (SBQ – the theoretical background as well as its psychometric characteristics and psychological correlates. The items were created on the basis of the definition of symbiotic personality (Johnson, 1994a. Participants and procedure For these initial survey development and cross-validation studies, the factor structure and psychometric properties of the SBQ were examined. To assess the SBQ’s reliability, the researchers conducted an exploratory factor analysis using a sample of 568 people. The analysis indicated that the Symbiotic Bond Questionnaire consists of 28 items that form four factors: Suppressing, Merging, Cognitive oversensitiveness, and Emotional sensitiveness. Results The symbiotic bond is associated with attachment styles (Suppressing and Cognitive oversensitiveness positively with insecure attachment, and Merging and Emotional sensitiveness positively with secure attachment, empathy (Suppressing and Cognitive oversensitiveness positively with personal distress, and Emotional sensitiveness positively with taking care of others and taking their point of view, differentiation of self (correlations indicate poor functioning of a person in terms of emotional and cognitive autonomy, interdependent-relational self (more relational people are more inclined to merging and emotional sensitiveness and goal-oriented activity (suppressing is negatively associated with strategic and with life enrichment orientation, and positively with avoidant orientation, while Cognitive oversensitiveness is associated with avoidant orientation and emotional sensitiveness with life enrichment orientation. Conclusions The measure is sufficiently reliable and valid. Implications and directions for future research on the measurement are considered.

  2. Effects of heartwood extractives on symbiotic protozoan communities and mortality in two termite species

    Science.gov (United States)

    Babar Hassan; Mark E. Mankowski; Grant Kirker; Sohail Ahmed

    2017-01-01

    Lower termites (Isoptera: Rhinotermitidae) are considered severe pests of wood in service, crops and plantation forests. Termites mechanically remove and digest lignocellulosic material as a food source. The ability to digest lignocellulose not only depends on their digestive physiology, but also on the symbiotic relationship between termites and their intestinal...

  3. Fabrication of living soft matter by symbiotic growth of unicellular microorganisms

    NARCIS (Netherlands)

    Das, Anupam A.K.; Bovill, James; Ayesh, Maram; Stoyanov, Simeon D.; Paunov, Vesselin N.

    2016-01-01

    We report the fabrication of living soft matter made as a result of the symbiotic relationship of two unicellular microorganisms. The material is composed of bacterial cellulose produced in situ by acetobacter (Acetobacter aceti NCIMB 8132) in the presence of photosynthetic microalgae

  4. Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns

    NARCIS (Netherlands)

    Sagrilo, E.

    2014-01-01

    Soil and plant responses to pyrogenic organic matter: carbon stability and symbiotic patterns Edvaldo Sagrilo Summary Pyrogenic organic matter (PyOM), also known as biochar, is the product of biomass combustion under low oxygen concentration. There

  5. Reproduction of a woodwasp, Urocerus japonicus (Hymenoptera: Siricidae) using no maternal symbiotic fungus

    Science.gov (United States)

    Hideshi Fukuda

    2003-01-01

    Most woodwasps (Siricidae) are symbiotically associated with the specific fungus, Amylostereum spp. Female adults inoculate the fungus during their oviposition in sapwood of the host trees (Morgan 1968). Woodwasp larvae can digest sapwood with low nutritional quality with the aid of symbiosis (Kukor and Martin 1983). In the earlier study, we...

  6. Pea mutant risnod27 as reference line for field assessment of impact of symbiotic nitrogen fixation

    Czech Academy of Sciences Publication Activity Database

    Biedermannová, E.; Novák, Karel; Vondrys, J.

    2002-01-01

    Roč. 25, č. 9 (2002), s. 2051-2066 ISSN 0190-4167 R&D Projects: GA ČR GA521/00/0937 Institutional research plan: CEZ:AV0Z5020903 Keywords : pea mutant * symbiotic nodules Subject RIV: EE - Microbiology, Virology Impact factor: 0.593, year: 2002

  7. Radio emission from the nova-like variable AC Cancri and the symbiotic variable AG Draconis

    International Nuclear Information System (INIS)

    Torbett, M.V.; Campbell, B.; Mount Wilson and Las Campanas Observatories, Pasadena, CA)

    1987-01-01

    Radio emission at 6 cm has been detected from the nova-like cataclysmic variable AC Cnc and the symbiotic variable AG Dra. The AC Cnc observation constitutes the first radio detection in this class of objects. The AG Dra source is probably resolved and appears to show asymmetric, extended structure. The radio emission can best be explained by thermal bremsstrahlung. 26 references

  8. Flora Robotica – Mixed Societies of Symbiotic Robot-Plant Bio-Hybrids

    DEFF Research Database (Denmark)

    Hamann, Heiko; Wahby, Mostafa; Schmickl, Thomas

    2015-01-01

    robotica. Our objective is to develop and to investigate closely linked symbiotic relationships between robots and natural plants and to explore the potentials of a plant-robot society able to produce architectural artifacts and living spaces. These robot-plant bio-hybrids create synergies that allow...

  9. Differential immune responses of Monochamus alternatus against symbiotic and entomopathogenic fungi.

    Science.gov (United States)

    Zhang, Wei; Meng, Jie; Ning, Jing; Qin, Peijun; Zhou, Jiao; Zou, Zhen; Wang, Yanhong; Jiang, Hong; Ahmad, Faheem; Zhao, Lilin; Sun, Jianghua

    2017-08-01

    Monochamus alternatus, the main vector beetles of invasive pinewood nematode, has established a symbiotic relationship with a native ectotrophic fungal symbiont, Sporothrix sp. 1, in China. The immune response of M. alternatus to S. sp. 1 in the coexistence of beetles and fungi is, however, unknown. Here, we report that immune responses of M. alternatus pupae to infection caused by ectotrophic symbiotic fungus S. sp. 1 and entomopathogenic fungus Beauveria bassiana differ significantly. The S. sp. 1 did not kill the beetles while B. bassiana killed all upon injection. The transcriptome results showed that the numbers of differentially expressed genes in M. alternatus infected with S. sp. 1 were 2-fold less than those infected with B. bassiana at 48 hours post infection. It was noticed that Toll and IMD pathways played a leading role in the beetle's immune system when infected by symbiotic fungus, but upon infection by entomopathogenic fungus, only the Toll pathway gets triggered actively. Furthermore, the beetles could tolerate the infection of symbiotic fungi by retracing their Toll and IMD pathways at 48 h. This study provided a comprehensive sequence resource of M. alternatus transcriptome for further study of the immune interactions between host and associated fungi.

  10. Extraction of Uranium from Seawater: Design and Testing of a Symbiotic System

    Energy Technology Data Exchange (ETDEWEB)

    Slocum, Alex [Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)

    2018-02-22

    The U.S. Department of Energy in October 2014 awarded the Massachusetts Institute of Technology (MIT) a Nuclear Energy University Program grant (DE-NE0008268) to investigate the design and testing of a symbiotic system to harvest uranium from seawater. As defined in the proposal, the goals for the project are: 1. Address the design of machines for seawater uranium mining. 2. Develop design rules for a uranium harvesting system that would be integrated into an offshore wind power tower. 3. Fabricate a 1/50th size scale prototype for bench and pool-testing to verify initial analysis and theory. 4. Design, build, and test a second 1/10th size scale prototype in the ocean for more comprehensive testing and validation. This report describes work done as part of DE-NE0008268 from 10/01/2014 to 11/30/2017 entitled, “Extraction of Uranium from Seawater: Design and Testing of a Symbiotic System.” This effort is part of the Seawater Uranium Recovery Program. This report details the publications and presentations to date on the project, an introduction to the project’s goals and background research into previous work done to achieve these goals thus far. From there, the report describes an algorithm developed during the project used to optimize the adsorption of uranium by changing mechanical parameters such as immersion time and adsorbent reuses is described. Next, a design tool developed as part of the project to determine the global feasibility of symbiotic uranium harvesting systems. Additionally, the report details work done on shell enclosures for uranium adsorption. Moving on, the results from the design, building, and testing of a 1/50th physical scale prototype of a highly feasible symbiotic uranium harvester is described. Then, the report describes the results from flume experiment used to determine the affect of enclosure shells on the uptake of uranium by the adsorbent they enclose. From there the report details the design of a Symbiotic Machine for Ocean u

  11. Interactions between non-symbiotic N2-fixing bacteria and plant roots in plant-microbial associations

    OpenAIRE

    Calvo Alegre, Olga-Cristina

    2009-01-01

    The development of biofertilizers on the basis of plant growth promoting rhizobacteria (PGPR) may be a promising approach to partially substitute costly and energy-consuming mineral fertilizers in agricultural plant production and to support agriculture in developing countries. A successful and competitive rhizosphere colonization of PGPR strains has been identified as a prerequisite for the expression of plant growth promoting effects. Apart from a wide range of external factors with an impa...

  12. Exploring the symbiotic pangenome of the nitrogen-fixing bacterium Sinorhizobium meliloti

    Energy Technology Data Exchange (ETDEWEB)

    Galardini, Marco [University of Florence; Mengoni, Alessio [University of Florence; Brilli, Matteo [Universite de Lyon, France; Pini, Francesco [University of Florence; Fioravanti, Antonella [University of Florence; Lucas, Susan [U.S. Department of Energy, Joint Genome Institute; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Cheng, Jan-Fang [U.S. Department of Energy, Joint Genome Institute; Goodwin, Lynne A. [Los Alamos National Laboratory (LANL); Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Daligault, Hajnalka E. [Los Alamos National Laboratory (LANL); Bruce, David [Los Alamos National Laboratory (LANL); Detter, J. Chris [U.S. Department of Energy, Joint Genome Institute; Tapia, Roxanne [Los Alamos National Laboratory (LANL); Han, Cliff [Los Alamos National Laboratory (LANL); Teshima, Hazuki [Los Alamos National Laboratory (LANL); Mocali, Stefano [Agrobiol & Pedol Ctr ABP, Agr Res Council, I-50121 Florence, Italy; Bazzicalupo, Marco [University of Florence; Biondi, Emanuele [University of Florence

    2011-01-01

    Background: Sinorhizobium meliloti is a model system for the studies of symbiotic nitrogen fixation. An extensive polymorphism at the genetic and phenotypic level is present in natural populations of this species, especially in relation with symbiotic promotion of plant growth. AK83 and BL225C are two nodule-isolated strains with diverse symbiotic phenotypes; BL225C is more efficient in promoting growth of the Medicago sativa plants than strain AK83. In order to investigate the genetic determinants of the phenotypic diversification of S. meliloti strains AK83 and BL225C, we sequenced the complete genomes for these two strains. Results: With sizes of 7.14 Mbp and 6.97 Mbp, respectively, the genomes of AK83 and BL225C are larger than the laboratory strain Rm1021. The core genome of Rm1021, AK83, BL225C strains included 5124 orthologous groups, while the accessory genome was composed by 2700 orthologous groups. While Rm1021 and BL225C have only three replicons (Chromosome, pSymA and pSymB), AK83 has also two plasmids, 260 and 70 Kbp long. We found 65 interesting orthologous groups of genes that were present only in the accessory genome, consequently responsible for phenotypic diversity and putatively involved in plant-bacterium interaction. Notably, the symbiosis inefficient AK83 lacked several genes required for microaerophilic growth inside nodules, while several genes for accessory functions related to competition, plant invasion and bacteroid tropism were identified only in AK83 and BL225C strains. Presence and extent of polymorphism in regulons of transcription factors involved in symbiotic interaction were also analyzed. Our results indicate that regulons are flexible, with a large number of accessory genes, suggesting that regulons polymorphism could also be a key determinant in the variability of symbiotic performances among the analyzed strains.

  13. Nitrogen-fixing bacteria in Mediterranean seagrass (Posidonia oceanica) roots

    KAUST Repository

    Garcias Bonet, Neus

    2016-03-09

    Biological nitrogen fixation by diazotrophic bacteria in seagrass rhizosphere and leaf epiphytic community is an important source of nitrogen required for plant growth. However, the presence of endophytic diazotrophs remains unclear in seagrass tissues. Here, we assess the presence, diversity and taxonomy of nitrogen-fixing bacteria within surface-sterilized roots of Posidonia oceanica. Moreover, we analyze the nitrogen isotopic signature of seagrass tissues in order to notice atmospheric nitrogen fixation. We detected nitrogen-fixing bacteria by nifH gene amplification in 13 out of the 78 roots sampled, corresponding to 9 locations out of 26 meadows. We detected two different types of bacterial nifH sequences associated with P. oceanica roots, which were closely related to sequences previously isolated from the rhizosphere of a salt marsh cord grass and a putative anaerobe. Nitrogen content of seagrass tissues showed low isotopic signatures in all the sampled meadows, pointing out the atmospheric origin of the assimilated nitrogen by seagrasses. However, this was not related with the presence of endophytic nitrogen fixers, suggesting the nitrogen fixation occurring in rhizosphere and in the epiphytic community could be an important source of nitrogen for P. oceanica. The low diversity of nitrogen-fixing bacteria reported here suggests species-specific relationships between diazotrophs and P. oceanica, revealing possible symbiotic interactions that could play a major role in nitrogen acquisition by seagrasses in oligotrophic environments where they form lush meadows.

  14. Improved Phytophthora resistance in commercial chickpea (Cicer arietinum) varieties negatively impacts symbiotic gene signalling and symbiotic potential in some varieties.

    Science.gov (United States)

    Plett, Jonathan M; Plett, Krista L; Bithell, Sean L; Mitchell, Chris; Moore, Kevin; Powell, Jeff R; Anderson, Ian C

    2016-08-01

    Breeding disease-resistant varieties is one of the most effective and economical means to combat soilborne diseases in pulse crops. Commonalities between pathogenic and mutualistic microbe colonization strategies, however, raises the concern that reduced susceptibility to pathogens may simultaneously reduce colonization by beneficial microbes. We investigate here the degree of overlap in the transcriptional response of the Phytophthora medicaginis susceptible chickpea variety 'Sonali' to the early colonization stages of either Phytophthora, rhizobial bacteria or arbuscular mycorrhizal fungi. From a total of 6476 genes differentially expressed in Sonali roots during colonization by any of the microbes tested, 10.2% were regulated in a similar manner regardless of whether it was the pathogenic oomycete or a mutualistic microbe colonizing the roots. Of these genes, 49.7% were oppositely regulated under the same conditions in the moderately Phytophthora resistant chickpea variety 'PBA HatTrick'. Chickpea varieties with improved resistance to Phytophthora also displayed lower colonization by rhizobial bacteria and mycorrhizal fungi leading to an increased reliance on N and P from soil. Together, our results suggest that marker-based breeding in crops such as chickpea should be further investigated such that plant disease resistance can be tailored to a specific pathogen without affecting mutualistic plant:microbe interactions. © 2016 John Wiley & Sons Ltd.

  15. Proteomic Analysis of the Soybean Symbiosome Identifies New Symbiotic Proteins*

    Science.gov (United States)

    Clarke, Victoria C.; Loughlin, Patrick C.; Gavrin, Aleksandr; Chen, Chi; Brear, Ella M.; Day, David A.; Smith, Penelope M.C.

    2015-01-01

    Legumes form a symbiosis with rhizobia in which the plant provides an energy source to the rhizobia bacteria that it uses to fix atmospheric nitrogen. This nitrogen is provided to the legume plant, allowing it to grow without the addition of nitrogen fertilizer. As part of the symbiosis, the bacteria in the infected cells of a new root organ, the nodule, are surrounded by a plant-derived membrane, the symbiosome membrane, which becomes the interface between the symbionts. Fractions containing the symbiosome membrane (SM) and material from the lumen of the symbiosome (peribacteroid space or PBS) were isolated from soybean root nodules and analyzed using nongel proteomic techniques. Bicarbonate stripping and chloroform-methanol extraction of isolated SM were used to reduce complexity of the samples and enrich for hydrophobic integral membrane proteins. One hundred and ninety-seven proteins were identified as components of the SM, with an additional fifteen proteins identified from peripheral membrane and PBS protein fractions. Proteins involved in a range of cellular processes such as metabolism, protein folding and degradation, membrane trafficking, and solute transport were identified. These included a number of proteins previously localized to the SM, such as aquaglyceroporin nodulin 26, sulfate transporters, remorin, and Rab7 homologs. Among the proteome were a number of putative transporters for compounds such as sulfate, calcium, hydrogen ions, peptide/dicarboxylate, and nitrate, as well as transporters for which the substrate is not easy to predict. Analysis of the promoter activity for six genes encoding putative SM proteins showed nodule specific expression, with five showing expression only in infected cells. Localization of two proteins was confirmed using GFP-fusion experiments. The data have been deposited to the ProteomeXchange with identifier PXD001132. This proteome will provide a rich resource for the study of the legume-rhizobium symbiosis. PMID

  16. Putative N2-fixing heterotrophic bacteria associated with dinoflagellate-Cyanobacteria consortia in the low-nitrogen Indian Ocean

    DEFF Research Database (Denmark)

    Farnelid, H.; Tarangkoon, Woraporn; Hansen, Gert

    2010-01-01

    , cloning, and sequencing. Cyanobacteria, heterotrophic bacteria and eukaryotic algae were recognized as symbionts of the heterotrophic dinoflagellates. nifH gene sequences were obtained from 23 of 37 (62%) specimens of dinoflagellates (Ornithocercus spp. and Amphisolenia spp.). Interestingly, only 2...... assemblages were often found in single host cells. This study provides the first insights into the nifH diversity of dinoflagellate symbionts and suggests a symbiotic co-existence of non-diazotrophic cyanobacteria and N2-fixing heterotrophic bacteria in heterotrophic dinoflagellates...

  17. Exploring the symbiotic pangenome of the nitrogen-fixing bacterium Sinorhizobium meliloti

    Directory of Open Access Journals (Sweden)

    Daligault Hajnalka

    2011-05-01

    Full Text Available Abstract Background Sinorhizobium meliloti is a model system for the studies of symbiotic nitrogen fixation. An extensive polymorphism at the genetic and phenotypic level is present in natural populations of this species, especially in relation with symbiotic promotion of plant growth. AK83 and BL225C are two nodule-isolated strains with diverse symbiotic phenotypes; BL225C is more efficient in promoting growth of the Medicago sativa plants than strain AK83. In order to investigate the genetic determinants of the phenotypic diversification of S. meliloti strains AK83 and BL225C, we sequenced the complete genomes for these two strains. Results With sizes of 7.14 Mbp and 6.97 Mbp, respectively, the genomes of AK83 and BL225C are larger than the laboratory strain Rm1021. The core genome of Rm1021, AK83, BL225C strains included 5124 orthologous groups, while the accessory genome was composed by 2700 orthologous groups. While Rm1021 and BL225C have only three replicons (Chromosome, pSymA and pSymB, AK83 has also two plasmids, 260 and 70 Kbp long. We found 65 interesting orthologous groups of genes that were present only in the accessory genome, consequently responsible for phenotypic diversity and putatively involved in plant-bacterium interaction. Notably, the symbiosis inefficient AK83 lacked several genes required for microaerophilic growth inside nodules, while several genes for accessory functions related to competition, plant invasion and bacteroid tropism were identified only in AK83 and BL225C strains. Presence and extent of polymorphism in regulons of transcription factors involved in symbiotic interaction were also analyzed. Our results indicate that regulons are flexible, with a large number of accessory genes, suggesting that regulons polymorphism could also be a key determinant in the variability of symbiotic performances among the analyzed strains. Conclusions In conclusions, the extended comparative genomics approach revealed a

  18. Stable and sporadic symbiotic communities of coral and algal holobionts

    Science.gov (United States)

    Hester, Eric R; Barott, Katie L; Nulton, Jim; Vermeij, Mark JA; Rohwer, Forest L

    2016-01-01

    Coral and algal holobionts are assemblages of macroorganisms and microorganisms, including viruses, Bacteria, Archaea, protists and fungi. Despite a decade of research, it remains unclear whether these associations are spatial–temporally stable or species-specific. We hypothesized that conflicting interpretations of the data arise from high noise associated with sporadic microbial symbionts overwhelming signatures of stable holobiont members. To test this hypothesis, the bacterial communities associated with three coral species (Acropora rosaria, Acropora hyacinthus and Porites lutea) and two algal guilds (crustose coralline algae and turf algae) from 131 samples were analyzed using a novel statistical approach termed the Abundance-Ubiquity (AU) test. The AU test determines whether a given bacterial species would be present given additional sampling effort (that is, stable) versus those species that are sporadically associated with a sample. Using the AU test, we show that coral and algal holobionts have a high-diversity group of stable symbionts. Stable symbionts are not exclusive to one species of coral or algae. No single bacterial species was ubiquitously associated with one host, showing that there is not strict heredity of the microbiome. In addition to the stable symbionts, there was a low-diversity community of sporadic symbionts whose abundance varied widely across individual holobionts of the same species. Identification of these two symbiont communities supports the holobiont model and calls into question the hologenome theory of evolution. PMID:26555246

  19. Genomics of Probiotic Bacteria

    Science.gov (United States)

    O'Flaherty, Sarah; Goh, Yong Jun; Klaenhammer, Todd R.

    Probiotic bacteria from the Lactobacillus and Bifidobacterium species belong to the Firmicutes and the Actinobacteria phylum, respectively. Lactobacilli are members of the lactic acid bacteria (LAB) group, a broadly defined family of microorganisms that ferment various hexoses into primarily lactic acid. Lactobacilli are typically low G + C gram-positive species which are phylogenetically diverse, with over 100 species documented to date. Bifidobacteria are heterofermentative, high G + C content bacteria with about 30 species of bifidobacteria described to date.

  20. 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.

  1. Genome-Wide Sensitivity Analysis of the Microsymbiont Sinorhizobium meliloti to Symbiotically Important, Defensin-Like Host Peptides

    Directory of Open Access Journals (Sweden)

    Markus F. F. Arnold

    2017-08-01

    Full Text Available The model legume species Medicago truncatula expresses more than 700 nodule-specific cysteine-rich (NCR signaling peptides that mediate the differentiation of Sinorhizobium meliloti bacteria into nitrogen-fixing bacteroids. NCR peptides are essential for a successful symbiosis in legume plants of the inverted-repeat-lacking clade (IRLC and show similarity to mammalian defensins. In addition to signaling functions, many NCR peptides exhibit antimicrobial activity in vitro and in vivo. Bacterial resistance to these antimicrobial activities is likely to be important for symbiosis. However, the mechanisms used by S. meliloti to resist antimicrobial activity of plant peptides are poorly understood. To address this, we applied a global genetic approach using transposon mutagenesis followed by high-throughput sequencing (Tn-seq to identify S. meliloti genes and pathways that increase or decrease bacterial competitiveness during exposure to the well-studied cationic NCR247 peptide and also to the unrelated model antimicrobial peptide polymyxin B. We identified 78 genes and several diverse pathways whose interruption alters S. meliloti resistance to NCR247. These genes encode the following: (i cell envelope polysaccharide biosynthesis and modification proteins, (ii inner and outer membrane proteins, (iii peptidoglycan (PG effector proteins, and (iv non-membrane-associated factors such as transcriptional regulators and ribosome-associated factors. We describe a previously uncharacterized yet highly conserved peptidase, which protects S. meliloti from NCR247 and increases competitiveness during symbiosis. Additionally, we highlight a considerable number of uncharacterized genes that provide the basis for future studies to investigate the molecular basis of symbiotic development as well as chronic pathogenic interactions.

  2. Bradyrhizobium namibiense sp. nov., a symbiotic nitrogen-fixing bacterium from root nodules of Lablab purpureus, hyacinth bean, in Namibia.

    Science.gov (United States)

    Grönemeyer, Jann Lasse; Bünger, Wiebke; Reinhold-Hurek, Barbara

    2017-10-16

    Four strains of symbiotic bacteria from root nodules of hyacinth bean (Lablab purpureus (L.) Sweet) from Namibia were previously identified as a novel group within the genus Bradyrhizobium. To confirm their taxonomic status, these strains were further characterized by taking a polyphasic approach. The type strain possessed 16S rRNA gene sequences identical to Bradyrhizobium paxllaeri LMTR 21 T and Bradyrhizobiumicense LMTR 13 T , the full-length sequences were identical to those retrieved from SAMN05230119 and SAMN05230120, respectively. However, the intergenic spacer sequences of the novel group showed identities of less than 93.1 % to described Bradyrhizobium species and were placed in a well-supported separate lineage in the phylogenetic tree. Phylogenetic analyses of six concatenated housekeeping genes, recA, glnII, gyrB, dnaK, atpD and rpoB, corroborated that the novel strains belonged to a lineage distinct from named species of the genus Bradyrhizobium, with highest sequence identities to Bradyrhizobiumjicamae and B. paxllaeri (below 93 %). The species status was validated by results of DNA-DNA hybridization and average nucleotide identity values of genome sequences. The combination of phenotypic characteristics from several tests, including carbon source utilization and antibiotic resistance, could be used to differentiate representative strains from recognized species of the genus Bradyrhizobium. Phylogenetic analysis of nodC and nifH genes placed the novel strains in a group with B. paxllaeri and B.lablabi. Novel strain 5-10 T induces effective nodules on Lablab purpureus, Vigna subterranea, Vigna unguiculata and Arachis hypogaea. Based on our results, we conclude that our strains represent a novel species for which the name Bradyrhizobium namibiense sp. nov. is proposed, with type strain 5-10 T [LMG 28789, DSM 100300, NTCCM0017 (Windhoek)].

  3. Bradyrhizobium kavangense sp. nov., a symbiotic nitrogen-fixing bacterium from root nodules of traditional Namibian pulses.

    Science.gov (United States)

    Lasse Grönemeyer, Jann; Hurek, T; Reinhold-Hurek, Barbara

    2015-12-01

    Eight strains of symbiotic bacteria from root nodules of local races of cowpea (Vigna unguiculata) and Bambara groundnut (Vigna subterranea) grown on subsistence farmers' fields in the Kavango region, Namibia, were previously characterized and identified as a novel group within the genus Bradyrhizobium. To clarify their taxonomic status, these strains were further characterized using a polyphasic approach. In phylogenetic analysis of the 16S rRNA gene sequence the novel group was most closely related to Bradyrhizobium iriomotense EK05T and Bradyrhizobium ingae BR 10250T, and to 'Bradyrhizobium arachidis' CCBAU 051107 in the ITS sequence analysis. Phylogenetic analysis of concatenated glnII-recA-rpoB-dnaK sequences placed the strains in a lineage distinct from named species of the genus Bradyrhizobium. The species status was validated by results of DNA-DNA hybridization. Phylogenetic analysis of nifH and nodC genes placed the novel strains in a group with 'B. arachidis' CCBAU 051107. The combination of phenotypic characteristics from several tests including carbon source utilization and antibiotic resistance could be used to differentiate representative strains from recognized species of the genus Bradyrhizobium. Novel strain 14-3T induces effective nodules on Vigna subterranea, Vigna unguiculata, Arachis hypogaea and Lablab purpureus. Based on the data presented, it is concluded that the strains represent a novel species of the genus Bradyrhizobium, for which the name Bradyrhizobium kavangense sp. nov. is proposed. The type strain is 14-3T [ = DSM 100299T = LMG 28790T = NTCCM 0012T (Windhoek)]. The DNA G+C content of strain 14-3T is 63.8 mol% (Tm).

  4. Lumichrome and riboflavin are two novel symbiotic signals eliciting developmental changes in both monocot and dicot plant species

    Directory of Open Access Journals (Sweden)

    Felix Dapare Dakora

    2015-09-01

    Full Text Available Lumichrome and riboflavin are novel molecules from rhizobial exudates that stimulate plant growth. Developmental changes elicited by lumichrome at very low nanomolar concentrations (5 nM include early initiation of trifoliate leaves, expansion of unifoliate and trifoliate leaves, increased stem elongation and leaf area, and consequently greater biomass accumulation in monocots and dicots. However, higher lumichrome concentration (50 nM depressed root development and reduced growth of unifoliate and second trifoliate leaves. Applying either 10 nM lumichrome, 10 nM ABA, or 10 ml of infective rhizobial cells (0.2 OD600 to roots of monocots and dicots for 44 h produced identical effects, which included decreased stomatal conductance and leaf transpiration in Bambara groundnut, soybean and maize, increased stomatal conductance and transpiration in cowpea and lupin, and elevated root respiration in maize (19% by rhizobia and 20% by lumichrome. Extracellular exudation of lumichrome, riboflavin and IAA was greater in N2-fixing rhizobia than non-fixing bacteria, indicating their role as symbiotic signals. Xylem concentration of lumichrome in cowpea and soybean was greater in plants inoculated with infective rhizobia and treated with lumichrome (61.2 µmol lumichrome.ml-1 sap, followed by uninoculated plants receiving lumichrome (41.12 µmol lumichrome.ml-1 sap, and lowest in uninoculated, lumichrome-free plants (26.8 µmol lumichrome.ml-1 sap. Overall, soybean showed greater xylem concentration of lumichrome and a correspondingly increased accumulation in leaves relative to cowpea. As a result, soybean exhibited dramatic developmental changes than cowpea. Taken together, lumichrome and riboflavin secreted by soil rhizobia function as environmental cues for sensing stress. The fact that exogenous application of ABA to plant roots caused the same effect as lumichrome on stomatal functioning suggests molecular cross-talk in plant response to environmental

  5. Balancing the organic load and light supply in symbiotic microalgal–bacterial biofilm reactors treating synthetic municipal wastewater

    NARCIS (Netherlands)

    Boelee, N.C.; Temmink, B.G.; Janssen, M.; Buisman, C.J.N.; Wijffels, R.H.

    2014-01-01

    Symbiotic microalgal–bacterial biofilms can be very attractive for municipal wastewater treatment. Microalgae remove nitrogen and phosphorus and simultaneously produce the oxygen that is required for the aerobic, heterotrophic degradation of organic pollutants. For the application of these biofilms

  6. Environmentally-related seasonal variation in symbiotic associations of heterotrophic dinoflagellates with cyanobacteria in the western Bay of Bengal

    Digital Repository Service at National Institute of Oceanography (India)

    Jyothibabu, R.; Madhu, N.V.; Maheswaran, P.A.; Devi, C.R.A.; Balasubramanian, T.; Nair, K.K.C.; Achuthankutty, C.T.

    In the western Bay of Bengal, some species of heterotrophic dinoflagellates recurrently show symbiotic associations with cyanobacteria (Synechococcus/Synechocystis). The occurrence of these associations is markedly higher during the spring...

  7. A Genomic Encyclopedia of the Root Nodule Bacteria: assessing genetic diversity through a systematic biogeographic survey.

    Science.gov (United States)

    Reeve, Wayne; Ardley, Julie; Tian, Rui; Eshragi, Leila; Yoon, Je Won; Ngamwisetkun, Pinyaruk; Seshadri, Rekha; Ivanova, Natalia N; Kyrpides, Nikos C

    2015-01-01

    Root nodule bacteria are free-living soil bacteria, belonging to diverse genera within the Alphaproteobacteria and Betaproteobacteria, that have the capacity to form nitrogen-fixing symbioses with legumes. The symbiosis is specific and is governed by signaling molecules produced from both host and bacteria. Sequencing of several model RNB genomes has provided valuable insights into the genetic basis of symbiosis. However, the small number of sequenced RNB genomes available does not currently reflect the phylogenetic diversity of RNB, or the variety of mechanisms that lead to symbiosis in different legume hosts. This prevents a broad understanding of symbiotic interactions and the factors that govern the biogeography of host-microbe symbioses. Here, we outline a proposal to expand the number of sequenced RNB strains, which aims to capture this phylogenetic and biogeographic diversity. Through the Vavilov centers of diversity (Proposal ID: 231) and GEBA-RNB (Proposal ID: 882) projects we will sequence 107 RNB strains, isolated from diverse legume hosts in various geographic locations around the world. The nominated strains belong to nine of the 16 currently validly described RNB genera. They include 13 type strains, as well as elite inoculant strains of high commercial importance. These projects will strongly support systematic sequence-based studies of RNB and contribute to our understanding of the effects of biogeography on the evolution of different species of RNB, as well as the mechanisms that determine the specificity and effectiveness of nodulation and symbiotic nitrogen fixation by RNB with diverse legume hosts.

  8. A Medicago truncatula tobacco retrotransposon insertion mutant collection with defects in nodule development and symbiotic nitrogen fixation.

    Science.gov (United States)

    Pislariu, Catalina I; Murray, Jeremy D; Wen, JiangQi; Cosson, Viviane; Muni, RajaSekhara Reddy Duvvuru; Wang, Mingyi; Benedito, Vagner A; Andriankaja, Andry; Cheng, Xiaofei; Jerez, Ivone Torres; Mondy, Samuel; Zhang, Shulan; Taylor, Mark E; Tadege, Million; Ratet, Pascal; Mysore, Kirankumar S; Chen, Rujin; Udvardi, Michael K

    2012-08-01

    A Tnt1-insertion mutant population of Medicago truncatula ecotype R108 was screened for defects in nodulation and symbiotic nitrogen fixation. Primary screening of 9,300 mutant lines yielded 317 lines with putative defects in nodule development and/or nitrogen fixation. Of these, 230 lines were rescreened, and 156 lines were confirmed with defective symbiotic nitrogen fixation. Mutants were sorted into six distinct phenotypic categories: 72 nonnodulating mutants (Nod-), 51 mutants with totally ineffective nodules (Nod+ Fix-), 17 mutants with partially ineffective nodules (Nod+ Fix+/-), 27 mutants defective in nodule emergence, elongation, and nitrogen fixation (Nod+/- Fix-), one mutant with delayed and reduced nodulation but effective in nitrogen fixation (dNod+/- Fix+), and 11 supernodulating mutants (Nod++Fix+/-). A total of 2,801 flanking sequence tags were generated from the 156 symbiotic mutant lines. Analysis of flanking sequence tags revealed 14 insertion alleles of the following known symbiotic genes: NODULE INCEPTION (NIN), DOESN'T MAKE INFECTIONS3 (DMI3/CCaMK), ERF REQUIRED FOR NODULATION, and SUPERNUMERARY NODULES (SUNN). In parallel, a polymerase chain reaction-based strategy was used to identify Tnt1 insertions in known symbiotic genes, which revealed 25 additional insertion alleles in the following genes: DMI1, DMI2, DMI3, NIN, NODULATION SIGNALING PATHWAY1 (NSP1), NSP2, SUNN, and SICKLE. Thirty-nine Nod- lines were also screened for arbuscular mycorrhizal symbiosis phenotypes, and 30 mutants exhibited defects in arbuscular mycorrhizal symbiosis. Morphological and developmental features of several new symbiotic mutants are reported. The collection of mutants described here is a source of novel alleles of known symbiotic genes and a resource for cloning novel symbiotic genes via Tnt1 tagging.

  9. Genomic analysis of the symbiotic marine crenarchaeon, Cenarchaeumsymbiosum

    Energy Technology Data Exchange (ETDEWEB)

    Hallam, Steven J.; Konstantinidis, Konstantinos T.; Brochier,Celine; Putnam, Nik; Schleper, Christa; Watanabe, Yoh-ichi; Sugahara,Junichi; Preston, Christina; de la Torre, Jose; Richardson, Paul M.; DeLong, Edward F.

    2006-06-24

    Crenarchaea are ubiquitous and abundant microbial constituents of soils, sediments, lakes and ocean waters, yet relatively little is known about their fundamental evolutionary, ecological, and physiological properties. To better describe the ubiquitous nonthermophilic Crenarchaea, we analyzed the genome sequence of one representative, the uncultivated sponge symbiont, Cenarchaeum symbiosum. C. symbiosum genotypes coinhabiting the same host partitioned into two dominant populations, corresponding to previously described a- and b-type ribosomal RNA variants. Although synthetic, overlapping a- and b-type ribotypes harbored significant genetic variability. A single tiling path comprising the dominant a-type genotype was assembled, and used to explore the biological properties of C. symbiosum and its planktonic relatives. Out of a total of 2,066 predicted open reading frames, 36% were more highly conserved with other Archaea. The remainder partitioned between bacteria (18%), eukaryotes (1.5%) and viruses (0.1%). A total of 525 open reading frames were more highly conserved with sequences derived from marine environmental genomic surveys, most probably representing orthologous genes found in free-living planktonic Crenarchaea. The remaining genes partitioned between functional RNAs (2.4%), and hypotheticals (42%) with limited homology to known functional genes. The latter category likely contains genes specifically involved in mediated archaeal-sponge symbiosis. Phylogenetic analyses placed C. symbiosum as a basal crenarchaeon, sharing specific genomic features in common with either Crenarchaea, Euryarchaea, or both. The genome sequence of C. symbiosum reflect a unique and unusual evolutionary, physiological, and ecological history, one remarkably distinct from that of any other previously known microbial lineage.

  10. Flavonoids and Strigolactones in Root Exudates as Signals in Symbiotic and Pathogenic Plant-Fungus Interactions

    Directory of Open Access Journals (Sweden)

    Horst Vierheilig

    2007-07-01

    Full Text Available Secondary plant compounds are important signals in several symbiotic and pathogenic plant-microbe interactions. The present review is limited to two groups of secondary plant compounds, flavonoids and strigolactones, which have been reported in root exudates. Data on flavonoids as signaling compounds are available from several symbiotic and pathogenic plant-microbe interactions, whereas only recently initial data on the role of strigolactones as plant signals in the arbuscular mycorrhizal symbiosis have been reported. Data from other plant-microbe interactions and strigolactones are not available yet. In the present article we are focusing on flavonoids in plant-fungalinteractions such as the arbuscular mycorrhizal (AM association and the signaling between different Fusarium species and plants. Moreover the role of strigolactones in the AM association is discussed and new data on the effect of strigolactones on fungi, apart from arbuscular mycorrhizal fungi (AMF, are provided.

  11. Symbiotic and antibiotic interactions between gut commensal microbiota and host immune system

    Directory of Open Access Journals (Sweden)

    Mantas Kazimieras Malys

    2015-01-01

    Full Text Available The human gut commensal microbiota forms a complex population of microorganisms that survive by maintaining a symbiotic relationship with the host. Amongst the metabolic benefits it brings, formation of adaptive immune system and maintenance of its homeostasis are functions that play an important role. This review discusses the integral elements of commensal microbiota that stimulate responses of different parts of the immune system and lead to health or disease. It aims to establish conditions and factors that contribute to gut commensal microbiota's transformation from symbiotic to antibiotic relationship with human. We suggest that the host-microbiota relationship has been evolved to benefit both parties and any changes that may lead to disease, are not due to unfriendly properties of the gut microbiota but due to host genetics or environmental changes such as diet or infection.

  12. Anomalously high intercombination line ratios in symbiotic stars - Extreme Bowen pumping?

    Science.gov (United States)

    Kastner, S. O.; Bhatia, A. K.; Feibelman, W. A.

    1989-01-01

    International Ultraviolet Explorer observations of the ratio of the O III intercombination lines near 1660 A are assembled, showing that the observed ratios in symbiotic stars are significantly higher than the theoretically predicted optically thin limit of 2.5. The presence of an enhancing physical process is thereby indicated. It is suggested that Bowen pumping of the lower level of the 1666.2 A line in an 'external saturation' limit, coupled with appreciable optical depth, could logically explain the high ratios. Some tentative evidence for this is presented and the relevance of far-infrared observations of the O III 51.8 and 88.3 micron lines in symbiotic sources is emphasized.

  13. [Physiological and agrochemical properties of different symbiotic genotypes of pea (Pisum sativum L.)].

    Science.gov (United States)

    Nazariuk, V M; Sidorova, K K; Shumny, V K; Kallimullina, F R; Klenova M I

    2006-01-01

    Physiological characters of symbiotic mutants of pea were studied: nodulation, activities of nitrogenase and nitrate reductase, chlorophyll content in leaves and their water-holding capacity, biomass accumulation, and nitrogen forms. The parameters reflecting the genotype state of the macrosymbiont under soil conditions considerably varied. Supernodulation mutants stood out against symbiotic pea genotypes by high contents of chlorophyll and nonprotein nitrogen compounds, high nitrogenase activity, and low nitrate reductase activity. The efficiency of the legume-rhizobium symbiosis was largely mediated by the macrosymbiont genotype. The highest atmospheric nitrogen fixation (50-80%) was observed in the parental pea varieties. Despite the highest nitrogenase activity in the nodules, the supernodulation mutants were inferior to the parental varieties by the nitrogen fixation capacity (40-60%), which was due to their low productivity.

  14. Comparative analyses of codon and amino acid usage in symbiotic island and core genome in nitrogen-fixing symbiotic bacterium Bradyrhizobium japonicum.

    Science.gov (United States)

    Das, Sabyasachi; Pan, Archana; Paul, Sandip; Dutta, Chitra

    2005-10-01

    Genes involved in the symbiotic interactions between the nitrogen-fixing endosymbiont Bradyrhizobium japonicum, and its leguminous host are mostly clustered in a symbiotic island (SI), acquired by the bacterium through a process of horizontal transfer. A comparative analysis of the codon and amino acid usage in core and SI genes/proteins of B. japonicum has been carried out in the present study. The mutational bias, translational selection, and gene length are found to be the major sources of variation in synonymous codon usage in the core genome as well as in SI, the strength of translational selection being higher in core genes than in SI. In core proteins, hydrophobicity is the main source of variation in amino acid usage, expressivity and aromaticity being the second and third important sources. But in SI proteins, aromaticity is the chief source of variation, followed by expressivity and hydrophobicity. In SI proteins, both the mean molecular weight and mean aromaticity of individual proteins exhibit significant positive correlation with gene expressivity, which violate the cost-minimization hypothesis. Investigation of nucleotide substitution patterns in B. japonicum and Mesorhizobium loti orthologous genes reveals that both synonymous and non-synonymous sites of highly expressed genes are more conserved than their lowly expressed counterparts and this conservation is more pronounced in the genes present in core genome than in SI.

  15. Whole-Genome Sequence of the Nitrogen-Fixing Symbiotic Rhizobium Mesorhizobium loti Strain TONO.

    Science.gov (United States)

    Shimoda, Yoshikazu; Hirakawa, Hideki; Sato, Shusei; Saeki, Kazuhiko; Hayashi, Makoto

    2016-10-06

    Mesorhizobium loti is the nitrogen-fixing microsymbiont for legumes of the genus Lotus Here, we report the whole-genome sequence of a Mesorhizobium loti strain, TONO, which is used as a symbiont for the model legume Lotus japonicus The whole-genome sequence of the strain TONO will be a solid platform for comparative genomics analyses and for the identification of genes responsible for the symbiotic properties of Mesorhizobium species. Copyright © 2016 Shimoda et al.

  16. Whole-Genome Sequence of the Nitrogen-Fixing Symbiotic Rhizobium Mesorhizobium loti Strain TONO

    Science.gov (United States)

    Hirakawa, Hideki; Sato, Shusei; Saeki, Kazuhiko; Hayashi, Makoto

    2016-01-01

    Mesorhizobium loti is the nitrogen-fixing microsymbiont for legumes of the genus Lotus. Here, we report the whole-genome sequence of a Mesorhizobium loti strain, TONO, which is used as a symbiont for the model legume Lotus japonicus. The whole-genome sequence of the strain TONO will be a solid platform for comparative genomics analyses and for the identification of genes responsible for the symbiotic properties of Mesorhizobium species. PMID:27795235

  17. A mini atlas of K-band spectra of southern symbiotic stars

    Czech Academy of Sciences Publication Activity Database

    Marchiano, P.E.; Cidale, L.S.; Arias, M.L.; Borges Fernandes, M.; Kraus, Michaela

    2015-01-01

    Roč. 57, č. 1 (2015), s. 87-89 E-ISSN 1669-9521 R&D Projects: GA ČR(CZ) GA14-21373S; GA MŠk(CZ) 7AMB14AR017 Institutional support: RVO:67985815 Keywords : binaries * symbiotic * stars Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics http://www.astronomiaargentina.org.ar/b57/2015BAAA...57...87M.pdf

  18. CHARACTERIZATION OF THE MOST LUMINOUS STAR IN M33: A SUPER SYMBIOTIC BINARY

    Energy Technology Data Exchange (ETDEWEB)

    Mikołajewska, Joanna; Iłkiewicz, Krystian [N. Copernicus Astronomical Center, Bartycka 18, PL 00-716 Warsaw (Poland); Caldwell, Nelson [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Shara, Michael M., E-mail: mikolaj@camk.edu.pl [Department of Astrophysics, American Museum of Natural History, Central Park West at 79th Street, New York, NY 10024 (United States)

    2015-01-30

    We present the first spectrum of the most luminous infrared star in M33, and use it to demonstrate that the object is almost certainly a binary composed of a massive O star and a dust-enshrouded red hypergiant. This is the most luminous symbiotic binary ever discovered. Its radial velocity is an excellent match to that of the hydrogen gas in the disk of M33, supporting our interpretation that it is a very young and massive binary star.

  19. Viability of L.casei in symbiotic carrot juice during fermentation and storage

    OpenAIRE

    Petreska Ivanovska, Tanja; Petrusevska Tozi, Lidija; Hadzieva, Jasmina; Smilkov, Katarina; Geskovski, Nikola; Mladenovska, Kristina

    2011-01-01

    Although dairy products are generally good matrices for the delivery of probiotics to humans and traditionally the most used, fruit juices are of growing interest, due to their pleasant taste profile and refreshing characteristics. However, the low survival rate of probiotics in fruit juices resulting from acid environment is of concern.In this study, carrot juice was inoculated with free probiotic cells of L. casei and symbiotic microparticles loaded with L. casei to compare the survival rat...

  20. Phisicochemical, sensory, and microbiological evaluation and development of symbiotic fermented drink

    OpenAIRE

    Dias, Mônica de Lucena Lira Aguiar; Salgado, Silvana Magalhães; Guerra, Nonete Barbosa; Livera, Alda Verônica Souza; Andrade, Samara Alvachian Cardoso; Ximenes, Graciliane Nobre da Cruz

    2013-01-01

    The goal of this study was to develop a symbiotic lacteous drink, evaluate its physicochemical and sensory characteristics, and verify the viability of Lactobacillus acidophilus in the drink. The milk serum-based drink consisted of 50% milk serum containing 10% saccharose, 25% powdered milk, 15% yacon pulp, and cultures of Lactobacillus acidophilus-La 5E and Bifidobacterium bifidum BB12. It was stored for up to 21 days under refrigeration. The milk serum-based drink was analyzed for protein, ...

  1. The effects of stimulating symbiotic fantasies on manifest pathology in schizophrenics: a revised formulation.

    Science.gov (United States)

    Mendelsohn, E M

    1981-09-01

    This study was designed as a further investigation of the ameliorative effects of stimulating a symbiotic fantasy in schizophrenics. Fifty-four adult male schizophrenic subjects were each seen individually for three experimental sessions. In each session there was exposure to a neutral subliminal stimulus followed by a baseline assessment of thought disorder and behavioral pathology. This was followed by exposure to one of three critical stimuli: a) a neutral control stimulus; b) the stimulus "mommy and I are one," designed to activate a fantasy of symbiotic gratification, and found in past studies to lead to pathology reduction; and c) "mommy and I are two," designed as a test of the specificity of oneness fantasy in producing symptomatic improvement. Each subject was exposed to the three critical simuli by counterbalanced order. Assessments of pathology were repeated after exposure to the experimental stimuli and comparisons were made with baseline measures. Results were: a) the subliminal symbiotic stimulus produced improvement on one of the measures of pathology, replicating findings from previous studies; and b) unexpectedly, the "mommy and I are two" stimulus led to pathology reduction on both dependent measures and proved significantly more ameliorative than the oneness stimulus. Associations obtained from subjects on a post hoc basis, the relationship between responses of individual subjects to the two stimuli, and the way in which order of presentation of the critical stimuli affected results supported the view that the twoness message also gratified symbiotic wishes while simultaneously providing reassurance against dangers associated with boundary loss. Results were discussed with an eye toward sharpening and refining the formulation advanced in the past to account for the ameliorative effects of the "oneness" stimulus.

  2. Anastomosis behavior differs between asymbiotic and symbiotic hyphae of Rhizophagus clarus.

    Science.gov (United States)

    Purin, Sonia; Morton, Joseph B

    2013-01-01

    The life history of arbuscular mycorrhizal fungi (AMF, Glomeromycota) consists of a short asymbiotic phase when spores germinate and a longer symbiotic phase where hyphae form a network within roots and subsequently in the rhizosphere. Hyphal anastomosis contributes to colony formation, yet this process has been studied mostly in the asymbiotic phase rather than in mycorrhizal plants because of methodological limitations. We sought to compare patterns of anastomosis during each phase of fungal growth by measuring hyphal fusions in genetically identical and different single spore isolates of Rhizophagus clarus from different environments and geographic locations. These isolates were genotyped with two anonymous markers of microsatellite-flanking regions. Anastomosis of hyphae from germinating spores was examined in axenic Petri dishes. A rhizohyphatron consisting of agar-coated glass slides bridging single or paired mycorrhizal sorghum plants allowed evaluation of anastomosis of symbiotic hyphae. Anastomosis of hyphae within a colony, defined here as a mycelium from an individual germinating spore or from mycorrhizal roots of one plant, occurred with similar frequencies (8-38%). However, anastomosis between paired colonies was observed in germinating spores from either genetically identical or different isolates, but it was never detected in symbiotic hyphae. The frequency of anastomosis in asymbiotic hyphae from paired interactions was low, occurring in fewer than 6% of hyphal contacts. These data suggest that anastomosis is relatively unconstrained when interactions occur within a colony but is confined to asymbiotic hyphae when interactions occur between paired colonies. This pattern of behavior suggests that asymbiotic and symbiotic phases of mycelium development by R. clarus may differ in function. Anastomosis in the asymbiotic phase may provide brief opportunities for gene flow between populations of this and possibly other AMF species.

  3. Diversity of Nitrogen Fixation Genes in the Symbiotic Intestinal Microflora of the Termite Reticulitermes speratus

    OpenAIRE

    Ohkuma, M.; Noda, S.; Usami, R.; Horikoshi, K.; Kudo, T.

    1996-01-01

    The diversity of nitrogen-fixing organisms in the symbiotic intestinal microflora of a lower termite, Reticulitermes speratus, was investigated without culturing the resident microorganisms. Fragments of the nifH gene, which encodes the dinitrogenase reductase, were directly amplified from the DNA of the mixed microbial population in the termite gut and were clonally isolated. The phylogenetic analysis of the nifH product amino acid sequences showed that there was a remarkable diversity of ni...

  4. Malic Enzyme Cofactor and Domain Requirements for Symbiotic N2 Fixation by Sinorhizobium meliloti▿ †

    Science.gov (United States)

    Mitsch, Michael J.; Cowie, Alison; Finan, Turlough M.

    2007-01-01

    The NAD+-dependent malic enzyme (DME) and the NADP+-dependent malic enzyme (TME) of Sinorhizobium meliloti are representatives of a distinct class of malic enzymes that contain a 440-amino-acid N-terminal region homologous to other malic enzymes and a 330-amino-acid C-terminal region with similarity to phosphotransacetylase enzymes (PTA). We have shown previously that dme mutants of S. meliloti fail to fix N2 (Fix−) in alfalfa root nodules, whereas tme mutants are unimpaired in their N2-fixing ability (Fix+). Here we report that the amount of DME protein in bacteroids is 10 times greater than that of TME. We therefore investigated whether increased TME activity in nodules would allow TME to function in place of DME. The tme gene was placed under the control of the dme promoter, and despite elevated levels of TME within bacteroids, no symbiotic nitrogen fixation occurred in dme mutant strains. Conversely, expression of dme from the tme promoter resulted in a large reduction in DME activity and symbiotic N2 fixation. Hence, TME cannot replace the symbiotic requirement for DME. In further experiments we investigated the DME PTA-like domain and showed that it is not required for N2 fixation. Thus, expression of a DME C-terminal deletion derivative or the Escherichia coli NAD+-dependent malic enzyme (sfcA), both of which lack the PTA-like region, restored wild-type N2 fixation to a dme mutant. Our results have defined the symbiotic requirements for malic enzyme and raise the possibility that a constant high ratio of NADPH + H+ to NADP in nitrogen-fixing bacteroids prevents TME from functioning in N2-fixing bacteroids. PMID:17071765

  5. Malic enzyme cofactor and domain requirements for symbiotic N2 fixation by Sinorhizobium meliloti.

    Science.gov (United States)

    Mitsch, Michael J; Cowie, Alison; Finan, Turlough M

    2007-01-01

    The NAD(+)-dependent malic enzyme (DME) and the NADP(+)-dependent malic enzyme (TME) of Sinorhizobium meliloti are representatives of a distinct class of malic enzymes that contain a 440-amino-acid N-terminal region homologous to other malic enzymes and a 330-amino-acid C-terminal region with similarity to phosphotransacetylase enzymes (PTA). We have shown previously that dme mutants of S. meliloti fail to fix N(2) (Fix(-)) in alfalfa root nodules, whereas tme mutants are unimpaired in their N(2)-fixing ability (Fix(+)). Here we report that the amount of DME protein in bacteroids is 10 times greater than that of TME. We therefore investigated whether increased TME activity in nodules would allow TME to function in place of DME. The tme gene was placed under the control of the dme promoter, and despite elevated levels of TME within bacteroids, no symbiotic nitrogen fixation occurred in dme mutant strains. Conversely, expression of dme from the tme promoter resulted in a large reduction in DME activity and symbiotic N(2) fixation. Hence, TME cannot replace the symbiotic requirement for DME. In further experiments we investigated the DME PTA-like domain and showed that it is not required for N(2) fixation. Thus, expression of a DME C-terminal deletion derivative or the Escherichia coli NAD(+)-dependent malic enzyme (sfcA), both of which lack the PTA-like region, restored wild-type N(2) fixation to a dme mutant. Our results have defined the symbiotic requirements for malic enzyme and raise the possibility that a constant high ratio of NADPH + H(+) to NADP in nitrogen-fixing bacteroids prevents TME from functioning in N(2)-fixing bacteroids.

  6. NITRITE REDUCTASE ACTIVITY OF NON-SYMBIOTIC HEMOGLOBINS FROM ARABIDOPSIS THALIANA†

    Science.gov (United States)

    Tiso, Mauro; Tejero, Jesús; Kenney, Claire; Frizzell, Sheila; Gladwin, Mark T.

    2013-01-01

    Plant non-symbiotic hemoglobins possess hexa-coordinate heme geometry similar to the heme protein neuroglobin. We recently discovered that deoxygenated neuroglobin converts nitrite to nitric oxide (NO), an important signaling molecule involved in many processes in plants. We sought to determine whether Arabidopsis thaliana non-symbiotic hemoglobins class 1 and 2 (AHb1 and AHb2) might function as nitrite reductases. We found that the reaction of nitrite with deoxygenated AHb1 and AHb2 generates NO gas and iron-nitrosyl-hemoglobin species. The bimolecular rate constants for nitrite reduction to NO are 19.8 ± 3.2 and 4.9 ± 0.2 M−1s−1, at pH = 7.4 and 25°C, respectively. We determined the pH dependence of these bimolecular rate constants and found a linear correlation with the concentration of protons, indicating the requirement for one proton in the reaction. Release of free NO gas during reaction in anoxic and hypoxic (2% oxygen) conditions was confirmed by chemiluminescence detection. These results demonstrate that deoxygenated AHb1 and AHb2 reduce nitrite to form NO via a mechanism analogous to that observed for hemoglobin, myoglobin and neuroglobin. Our findings suggest that during severe hypoxia and in the anaerobic plant roots, especially in water submerged species, non-symbiotic hemoglobins provide a viable pathway for NO generation via nitrite reduction. PMID:22620259

  7. Proteome changes in Oncidium sphacelatum (Orchidaceae) at different trophic stages of symbiotic germination.

    Science.gov (United States)

    Valadares, R B S; Perotto, S; Santos, E C; Lambais, M R

    2014-07-01

    Mutualistic symbioses between plants and fungi are a widespread phenomenon in nature. Particularly in orchids, association with symbiotic fungi is required for seed germination and seedling development. During the initial stages of symbiotic germination, before the onset of photosynthesis, orchid protocorms are fully mycoheterotrophic. The molecular mechanisms involved in orchid symbiotic germination and development are largely unknown, but it is likely that changes in plant energy metabolism and defense-related responses play a central role in these processes. We have used 2D-LC-MS/MS coupled to isobaric tagging for relative and absolute quantification to identify proteins with differential accumulation in Oncidium sphacelatum at different stages of mycorrhizal protocorm development (achlorophyllous and green protocorms) after seed inoculation with a Ceratobasidium sp. isolate. We identified and quantified 88 proteins, including proteins putatively involved in energy metabolism, cell rescue and defense, molecular signaling, and secondary metabolism. Quantitative analysis showed that the expected changes in carbon metabolism in green protocorms were accompanied by enhanced accumulation of proteins involved in the modulation of reactive oxygen species homeostasis, defense-related responses, and phytoalexins and carotenoid biosynthesis. Our results suggest profound metabolic changes in orchid protocorms during the switch from the fully mycoheterotrophic to the photosynthetic stage. Part of these changes may be also related to the obligatory nature of the interaction with the endomycorrhizal fungus.

  8. Symbiotic Sensing for Energy-Intensive Tasks in Large-Scale Mobile Sensing Applications

    Directory of Open Access Journals (Sweden)

    Duc V. Le

    2017-11-01

    Full Text Available Energy consumption is a critical performance and user experience metric when developing mobile sensing applications, especially with the significantly growing number of sensing applications in recent years. As proposed a decade ago when mobile applications were still not popular and most mobile operating systems were single-tasking, conventional sensing paradigms such as opportunistic sensing and participatory sensing do not explore the relationship among concurrent applications for energy-intensive tasks. In this paper, inspired by social relationships among living creatures in nature, we propose a symbiotic sensing paradigm that can conserve energy, while maintaining equivalent performance to existing paradigms. The key idea is that sensing applications should cooperatively perform common tasks to avoid acquiring the same resources multiple times. By doing so, this sensing paradigm executes sensing tasks with very little extra resource consumption and, consequently, extends battery life. To evaluate and compare the symbiotic sensing paradigm with the existing ones, we develop mathematical models in terms of the completion probability and estimated energy consumption. The quantitative evaluation results using various parameters obtained from real datasets indicate that symbiotic sensing performs better than opportunistic sensing and participatory sensing in large-scale sensing applications, such as road condition monitoring, air pollution monitoring, and city noise monitoring.

  9. Physiochemical Properties and Probiotic Survivability of Symbiotic Corn-Based Yogurt-Like Product.

    Science.gov (United States)

    Wang, Cuina; Zheng, Huajie; Liu, Tingting; Wang, Dawei; Guo, Mingruo

    2017-09-01

    Corn is a major grain produced in northern China. Corn-based functional food products are very limited. In this study, a symbiotic corn-based yogurt-like product was developed. Corn milk was prepared through grinding, extrusion and milling, and hydration processes. Corn extrudate was prepared under the optimized conditions of corn flour particle size yogurt-like product was: total solids (17.13 ± 0.31), protein (1.12 ± 0.03), fat (0.30 ± 0.05), carbohydrates (15.14 ± 0.19), and ash (0.16 ± 0.02), respectively. pH value of this symbiotic product decreased from 4.50 ± 0.03 to 3.88 ± 0.13 and the population of L. plantarum declined from 7.8 ± 0.09 to 7.1 ± 0.14 log CFU/mL during storage at 4 °C. SDS-PAGE analysis showed that there were no changes in protein profile during storage. Texture and consistency were also stable during the period of this study. It can be concluded that a set-type corn-based symbiotic yogurt-like product with good texture and stability was successfully developed that would be a good alternative to the dairy yogurt. © 2017 Institute of Food Technologists®.

  10. The synthesis of mycosporine-like amino acids (MAAs) by cultured, symbiotic dinoflagellates.

    Science.gov (United States)

    T Banaszak1 A; LaJeunesse; Trench

    2000-06-28

    We tested the hypothesis that there is a relation between phylotypes (phylogenetic types, as determined by restriction fragment length polymorphism (RFLP) and partial sequence analysis of the small subunit ribosomal RNA gene (SSUrDNA)) and the synthesis of mycosporine-like amino acids (MAAs) by symbiotic dinoflagellates under the influence of ultraviolet radiation (UV-B/A) and photosynthetically active radiation (PAR). We exposed 27 isolates of symbiotic dinoflagellates simultaneously to UV-B/A and PAR, and subsequently determined the MAAs present in cell extracts and in the media. The algae used included 24 isolates of Symbiodinium spp. originating from jellyfishes, sea anemones, zoanthids, scleractinians, octocorals, and bivalves, and three others in the genera Gymnodinium, Gloeodinium and Amphidinium from a jellyfish, an hydrocoral and a flatworm, respectively. In this study, all of the phylotype A Symbiodinium spp. synthesized up to three identified MAAs. None of the 11 cultured phylotypes B and C Symbiodinium spp. synthesized MAAs. The three non-Symbiodinium symbionts also synthesized up to three MAAs. The results support a conclusion that phylotype A Symbiodinium spp. have a high predilection for the synthesis of MAAs, while phylotypes B and C do not. Synthesis of MAAs by symbiotic dinoflagellates in culture does not appear to relate directly to depths or to the UV exposure regimes from which the consortia were collected.

  11. Symbiotic prokaryotic communities from different populations of the giant barrel sponge, Xestospongia muta.

    Science.gov (United States)

    Fiore, Cara L; Jarett, Jessica K; Lesser, Michael P

    2013-12-01

    The prokaryotic community composition of the ecologically dominant sponge, Xestospongia muta, and the variability of this community across in different populations of sponges from the Caribbean and Bahamas were quantified using 454 pyrosequencing of the 16S rRNA gene. The symbiotic prokaryotic communities of X. muta were significantly different than the surrounding bacterioplankton communities while an analysis of similarity (ANOSIM) of the sponge prokaryotic symbionts from three geographically distant sites showed that both symbiont and bacterioplankton populations were significantly different between locations. Comparisons of individual sponges based on the UniFrac P-test also revealed significant differences in community composition between individual sponges. The sponges harbored a variety of phylum level operational taxonomic units (OTUs) common to many sponges, including Cyanobacteria, Poribacteria, Acidobacteria, Chloroflexi, and Gemmatimonadetes, but four additional symbiotic phyla, previously not reported for this sponge, were observed. Additionally, a diverse archaeal community was also recovered from X. muta including sequences representing the phyla Euryarchaeota and Thaumarchaeota. These results have important ecological implications for the understanding of host-microbe associations, and provide a foundation for future studies addressing the functional roles these symbiotic prokaryotes have in the biology of the host sponge and the nutrient biogeochemistry of coral reefs. © 2013 The Authors. MicrobiologyOpen published by John Wiley & Sons Ltd.

  12. Far-infrared data for symbiotic stars. II. The IRAS survey observations

    International Nuclear Information System (INIS)

    Kenyon, S.J.; Fernandez-Castro, T.; Stencel, R.E.

    1988-01-01

    IRAS survey data for all known symbiotic binaries are reported. S type systems have 25 micron excesses much larger than those of single red giant stars, suggesting that these objects lose mass more rapidly than do normal giants. D type objects have far-IR colors similar to those of Mira variables, implying mass-loss rate of about 10 to the -6th solar masses/yr. The near-IR extinctions of the D types indicate that their Mira components are enshrouded in optically thick dust shells, while their hot companions lie outside the shells. If this interpretation of the data is correct, then the very red near-IR colors of D type symbiotic stars are caused by extreme amounts of dust absorption rather than dust emission. The small group of D prime objects possesses far-IR colors resembling those of compact planetary nebulae or extreme OH/IR stars. It is speculated that these binaries are not symbiotic stars at all, but contain a hot compact star and an exasymptotic branch giant which is in the process of ejecting a planetary nebula shell. 42 references

  13. Temperature-mediated local adaptation alters the symbiotic function in arbuscular mycorrhiza.

    Science.gov (United States)

    Yang, Rong; Cai, Xiaobu; Li, Xiaolin; Christie, Peter; Zhang, Junling; Gai, Jingping

    2017-07-01

    Variation in the symbiotic function of arbuscular mycorrhizal fungi (AM fungi) has been demonstrated among distinct biotic and abiotic interactions. However, there is little knowledge on how local temperature conditions influence the functional divergence of AM symbionts in alpine ecosystems. Here, we conduct a reciprocal inoculation experiment to explore the three-way interactions among plants, AM fungal inoculum and temperature at sites of contrasting elevation. Evidence of local adaptation of plant growth was found only under low temperature conditions, with no consistent local versus foreign effect found in AM fungal performance. The origin of either the plant or the inoculum relative to the temperature was important in explaining symbiotic function. Specifically, when inoculum and temperature were sympatric but allopatric to the plant, poor adaptation by the plant to the novel environment was clearly found under both temperature conditions. Further analysis found that the symbiotic function was inversely related to fungal diversity under high temperature conditions. These results suggest that local adaptation represents a powerful factor in the establishment of novel combinations of plant, inoculum and temperature, and confirms the importance of taking into account both biotic and abiotic interactions in the prediction of the response of symbionts to global environmental change. © 2017 Society for Applied Microbiology and John Wiley & Sons Ltd.

  14. Symbiotics and Aloe vera and Symphytum officinale extracts in broiler feed

    Directory of Open Access Journals (Sweden)

    Paula Rodrigues Oliveira

    2016-09-01

    Full Text Available This study aimed to test the effects of dietary Aloe vera and Symphytum officinale extracts added separately or in combination with symbiotics on the performance, nutrient utilization, serum biochemical parameters, biometrics, and intestinal histomorfometry of broilers. The experiment had a randomized block design with five treatments and six replicates of ten broilers each. Treatments were as follows: negative control and positive control (diet without and with antibiotic, respectively; 0.2% Aloe vera (AV; 0.2% Symphytum officinale (S; 0.2% functional supplement, composed of symbiotics fermented in Aloe vera and comfrey plant extracts (S+PE. At seven days of age, FI of birds fed the Aloe vera extracts diets were lower than that observed for birds consuming the diet with Symphytum officinale extract and S+PE. Broiler performance remained unaffected by treatments at others ages evaluated. At 10 to 14 days of age the lowest ADCDM ADCCP was shown in group feed NC. The highest ADCCP was observed in PC control group and in diets supplemented with Aloe vera and S+PE. Serum levels of cholesterol, triglycerides, and phosphorus were affected by addition of extracts at seven, 21, and 35 days of age. The longest duodenal villi were observed in broilers fed S+PE diets at seven days of age. Aloe vera and Symphytum officinale extracts and symbiotics can be used in broiler diets as an alternative to growth-promoting antibiotics.

  15. How honey kills bacteria

    NARCIS (Netherlands)

    Kwakman, Paulus H. S.; te Velde, Anje A.; de Boer, Leonie; Speijer, Dave; Vandenbroucke-Grauls, Christina M. J. E.; Zaat, Sebastian A. J.

    2010-01-01

    With the rise in prevalence of antibiotic-resistant bacteria, honey is increasingly valued for its antibacterial activity. To characterize all bactericidal factors in a medical-grade honey, we used a novel approach of successive neutralization of individual honey bactericidal factors. All bacteria

  16. [The influence of symbiotics in multi-organ failure: randomised trial].

    Science.gov (United States)

    López de Toro Martín-Consuegra, Ismael; Sanchez-Casado, Marcelino; Pérez-Pedrero Sánchez-Belmonte, M José; López-Reina Torrijos, Pilar; Sánchez-Rodriguez, Pilar; Raigal-Caño, Ana; Heredero-Galvez, Eva; Zubigaray, Susana Brea-; Arrese-Cosculluela, M Ángeles

    2014-08-19

    To assess whether the administration of symbiotic preparations in patients with multi-organ failure (MOF) diminishes the evolution of the failure, the inflammatory response generated, the colonization pattern and the Intensive Care Unit (ICU) infectious illness. Randomized and controlled trial. All patients with MOF were included. Neutropenia and acute pancreatitis patients were excluded. A symbiotic (Simbiotic Drink) was administered via enteral feeding during the first 7 days. Variables of interest were: Sequential Organ Failure Assessment (SOFA) score evolution, systemic concentrations of lactate, fibrinogen and D-dimer; skin and mucosa colonization and infectious disease register. Eighty-nine patients were included; 46 in the symbiotic group (SG) and 43 in the control group (CG). There were 68.5% males, with a median age of 69 years. There were no significant differences in the patients' fundamental characteristics (medical history, age, reason for admission, severity scores), nor in the length of ICU stay or in mortality. Comparing the SG with the CG, there were lower lactate levels on the second day, more fibrinogen levels on the days 5 and 7, and lower D-dimer levels on the day 7. Eight hundred and ninety-five cultures were performed for colonization assessment, with isolation of 528 microorganisms. No differences in microbiological resistance were found; there were more colonization in the SG by Candida in mucous membranes after the third day; this situation resolved after stopping symbiotic administration. Twenty-two patients suffered an infectious disease in ICU, 14 in SG (42.4%) and 19 in CG (57.6%). Although no differences were found in the microbiological pattern, there was a predominance of Candida spp. over other microorganisms (4 vs. 0 cases). The symbiotic preparation Simbiotic Drink, administered in MOF, results in differences to improve the early lactate levels and late fibrinogen/D-dimer levels as well as mucosa colonization by Candida. There

  17. Antibiotics from predatory bacteria

    Directory of Open Access Journals (Sweden)

    Juliane Korp

    2016-03-01

    Full Text Available Bacteria, which prey on other microorganisms, are commonly found in the environment. While some of these organisms act as solitary hunters, others band together in large consortia before they attack their prey. Anecdotal reports suggest that bacteria practicing such a wolfpack strategy utilize antibiotics as predatory weapons. Consistent with this hypothesis, genome sequencing revealed that these micropredators possess impressive capacities for natural product biosynthesis. Here, we will present the results from recent chemical investigations of this bacterial group, compare the biosynthetic potential with that of non-predatory bacteria and discuss the link between predation and secondary metabolism.

  18. Onion thrips, Thrips tabaci, have gut bacteria that are closely related to the symbionts of the western flower thrips, Frankliniella occidentalis.

    Science.gov (United States)

    de Vries, Egbert J; van der Wurff, André W G; Jacobs, Gerrit; Breeuwer, Johannes A J

    2008-01-01

    It has been shown that many insects have Enterobacteriaceae bacteria in their gut system. The western flower thrips, Frankliniella occidentalis Pergande [Thysanoptera: Thripidae], has a symbiotic relation with Erwinia species gut bacteria. To determine if other Thripidae species have similar bacterial symbionts, the onion thrips, Thrips tabaci, was studied because, like F. occidentalis, it is phytophagous. Contrary to F. occidentalis, T. tabaci is endemic in Europe and biotypes have been described. Bacteria were isolated from the majority of populations and biotypes of T. tabaci examined. Bacteria were present in high numbers in most individuals of the populations studied. Like F. occidentalis, T. tabaci contained one type of bacterium that clearly outnumbered all other types present in the gut. This bacterium was identified as an Erwinia species, as was also the case for F. occidentalis. However, its biochemical characteristics and 16S rDNA sequence differed from the bacteria present in F. occidentalis.

  19. Hydrogen production by nonphotosynthetic bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Huang, S.D.; Secor, C.K.; Zweig, R.M.; Ascione, R.

    1984-01-01

    H-producing nonphotosynthetic bacteria are identified and H from sewage treatment plants, H from rumen bacteria, and large-scale production of H through the genetic manipulation of H-producing nonphotosynthetic bacteria are discussed. (Refs. 36).

  20. [Darwin and bacteria].

    Science.gov (United States)

    Ledermann D, Walter

    2009-02-01

    As in 2009 the scientific world celebrates two hundreds years from the birthday of Charles Darwin and one hundred and fifty from the publication of The Origin of Species, an analysis of his complete work is performed, looking for any mention of bacteria. But it seems that the great naturahst never took knowledge about its existence, something rather improbable in a time when the discovery of bacteria shook the medical world, or he deliberately ignored them, not finding a place for such microscopic beings into his theory of evolution. But the bacteria badly affected his familiar life, killing scarlet fever one of his children and worsening to death the evolution of tuberculosis of his favourite Annie. Darwin himself could suffer the sickness of Chagas, whose etiological agent has a similar level to bacteria in the scale of evolution.

  1. Extracellular communication in bacteria

    DEFF Research Database (Denmark)

    Chhabra, S.R.; Philipp, B.; Eberl, L.

    2005-01-01

    molecules, in different Gram-positive and Gram-negative bacteria they control pathogenicity, secondary metabolite production, biofilm differentiation, DNA transfer and bioluminescence. The development of biosensors for the detection of these signal molecules has greatly facilitated their subsequent chemical...

  2. Use of nitrogen-fixing bacteria as biofertiliser for non-legumes: prospects and challenges.

    Science.gov (United States)

    Bhattacharjee, Rumpa Biswas; Singh, Aqbal; Mukhopadhyay, S N

    2008-08-01

    The potential of nitrogen-fixing (NF) bacteria to form a symbiotic relationship with leguminous plants and fix atmospheric nitrogen has been exploited in the field to meet the nitrogen requirement of the latter. This phenomenon provides an alternative to the use of the nitrogenous fertiliser whose excessive and imbalanced use over the decades has contributed to green house emission (N2O) and underground water leaching. Recently, it was observed that non-leguminous plants like rice, sugarcane, wheat and maize form an extended niche for various species of NF bacteria. These bacteria thrive within the plant, successfully colonizing roots, stems and leaves. During the association, the invading bacteria benefit the acquired host with a marked increase in plant growth, vigor and yield. With increasing population, the demand of non-leguminous plant products is growing. In this regard, the richness of NF flora within non-leguminous plants and extent of their interaction with the host definitely shows a ray of hope in developing an ecofriendly alternative to the nitrogenous fertilisers. In this review, we have discussed the association of NF bacteria with various non-leguminous plants emphasizing on their potential to promote host plant growth and yield. In addition, plant growth-promoting traits observed in these NF bacteria and their mode of interaction with the host plant have been described briefly.

  3. Tetrodotoxin-Producing Bacteria: Detection, Distribution and Migration of the Toxin in Aquatic Systems

    Directory of Open Access Journals (Sweden)

    Timur Yu. Magarlamov

    2017-05-01

    Full Text Available This review is devoted to the marine bacterial producers of tetrodotoxin (TTX, a potent non-protein neuroparalytic toxin. In addition to the issues of the ecology and distribution of TTX-producing bacteria, this review examines issues relating to toxin migration from bacteria to TTX-bearing animals. It is shown that the mechanism of TTX extraction from toxin-producing bacteria to the environment occur through cell death, passive/active toxin excretion, or spore germination of spore-forming bacteria. Data on TTX microdistribution in toxic organs of TTX-bearing animals indicate toxin migration from the digestive system to target organs through the transport system of the organism. The role of symbiotic microflora in animal toxicity is also discussed: despite low toxin production by bacterial strains in laboratory conditions, even minimal amounts of TTX produced by intestinal microflora of an animal can contribute to its toxicity. Special attention is paid to methods of TTX detection applicable to bacteria. Due to the complexity of toxin detection in TTX-producing bacteria, it is necessary to use several methods based on different methodological approaches. Issues crucial for further progress in detecting natural sources of TTX investigation are also considered.

  4. 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

  5. Treatment of antimony mine drainage: challenges and opportunities with special emphasis on mineral adsorption and sulfate reducing bacteria.

    Science.gov (United States)

    Li, Yongchao; Hu, Xiaoxian; Ren, Bozhi

    2016-01-01

    The present article summarizes antimony mine distribution, antimony mine drainage generation and environmental impacts, and critically analyses the remediation approach with special emphasis on iron oxidizing bacteria and sulfate reducing bacteria. Most recent research focuses on readily available low-cost adsorbents, such as minerals, wastes, and biosorbents. It is found that iron oxides prepared by chemical methods present superior adsorption ability for Sb(III) and Sb(V). However, this process is more costly and iron oxide activity can be inhibited by plenty of sulfate in antimony mine drainage. In the presence of sulfate reducing bacteria, sulfate can be reduced to sulfide and form Sb(2)S(3) precipitates. However, dissolved oxygen and lack of nutrient source in antimony mine drainage inhibit sulfate reducing bacteria activity. Biogenetic iron oxide minerals from iron corrosion by iron-oxidizing bacteria may prove promising for antimony adsorption, while the micro-environment generated from iron corrosion by iron oxidizing bacteria may provide better growth conditions for symbiotic sulfate reducing bacteria. Finally, based on biogenetic iron oxide adsorption and sulfate reducing bacteria followed by precipitation, the paper suggests an alternative treatment for antimony mine drainage that deserves exploration.

  6. Nutrient scavenging activity and antagonistic factors of non-photobiont lichen-associated bacteria: a review.

    Science.gov (United States)

    Sigurbjörnsdóttir, M Auður; Andrésson, Ólafur S; Vilhelmsson, Oddur

    2016-04-01

    Lichens are defined as the specific symbiotic structure comprising a fungus and a green alga and/or cyanobacterium. Up until recently, non-photobiont endothallic bacteria, while known to be present in large numbers, have generally been dismissed as functionally irrelevant cohabitants of the lichen thallus, or even environmental contaminants. Recent analyses of lichen metagenomes and innovative co-culture experiments have uncovered a functionally complex community that appears to contribute to a healthy lichen thallus in several ways. Lichen-associated bacteriomes are typically dominated by several lineages of Proteobacteria, some of which may be specific for lichen species. Recent work has implicated members of these lineages in several important ecophysiological roles. These include nutrient scavenging, including mobilization of iron and phosphate, nitrogen fixation, cellulase, xylanase and amylase activities, and oxidation of recalcitrant compounds, e.g. aromatics and aliphatics. Production of volatile organic compounds, conferring antibacterial and antifungal activity, has also been demonstrated for several lichen-associated isolates. In the present paper we review the nature of non-phototrophic endolichenic bacteria associated with lichens, and give insight into the current state of knowledge on their importance the lichen symbiotic association.

  7. Micro-particle transporting system using galvanotactically stimulated apo-symbiotic cells of Paramecium bursaria.

    Science.gov (United States)

    Furukawa, Shunsuke; Karaki, Chiaki; Kawano, Tomonori

    2009-01-01

    It is well known that Paramecium species including green paramecia (Paramecium bursaria) migrate towards the anode when exposed to an electric field in a medium. This type of a cellular movement is known as galvanotaxis. Our previous study revealed that an electric stimulus given to P bursaria is converted to a galvanotactic cellular movement by involvement of T-type calcium channel on the plasma membrane [Aonuma et al. (2007), Z. Naturforsch. 62c, 93-102]. This phenomenon has attracted the attention of bioengineers in the fields of biorobotics or micro-robotics in order to develop electrically controllable micromachineries. Here, we demonstrate the galvanotactic controls of the cellular migration of P bursaria in capillary tubes (diameter, 1-2 mm; length, 30-240 mm). Since the Paramecium cells take up particles of various sizes, we attempted to use the electrically stimulated cells of P bursaria as the vehicle for transportation of micro-particles in the capillary system. By using apo-symbiotic cells of P bursaria obtained after forced removal of symbiotic algae, the uptake of the particles could be maximized and visualized. Then, electrically controlled transportations of particle-filled apo-symbiotic P bursaria cells were manifested. The particles transported by electrically controlled cells (varying in size from nm to /m levels) included re-introduced green algae, fluorescence-labeled polystyrene beads, magnetic microspheres, emerald green fluorescent protein (EmGFP)-labeled cells of E. coli, Indian ink, and crystals of zeolite (hydrated aluminosilicate minerals with a micro-porous structure) and some metal oxides. Since the above demonstrations were successful, we concluded that P bursaria has a potential to be employed as one of the micro-biorobotic devices used in BioMEMS (biological micro-electro-mechanical systems).

  8. Using In Situ Symbiotic Seed Germination to Restore Over-collected Medicinal Orchids in Southwest China

    Directory of Open Access Journals (Sweden)

    Shi-Cheng Shao

    2017-06-01

    Full Text Available Due to increasing demand for medicinal and horticultural uses, the Orchidaceae is in urgent need of innovative and novel propagation techniques that address both market demand and conservation. Traditionally, restoration techniques have been centered on ex situ asymbiotic or symbiotic seed germination techniques that are not cost-effective, have limited genetic potential and often result in low survival rates in the field. Here, we propose a novel in situ advanced restoration-friendly program for the endangered epiphytic orchid species Dendrobium devonianum, in which a series of in situ symbiotic seed germination trials base on conspecific fungal isolates were conducted at two sites in Yunnan Province, China. We found that percentage germination varied among treatments and locations; control treatments (no inoculum did not germinate at both sites. We found that the optimal treatment, having the highest in situ seed germination rate (0.94-1.44% with no significant variation among sites, supported a warm, moist and fixed site that allowed for light penetration. When accounting for seed density, percentage germination was highest (2.78-2.35% at low densities and did not vary among locations for the treatment that supported optimal conditions. Similarly for the same treatment, seed germination ranged from 0.24 to 5.87% among seasons but also did vary among sites. This study reports on the cultivation and restoration of an endangered epiphytic orchid species by in situ symbiotic seed germination and is likely to have broad application to the horticulture and conservation of the Orchidaceae.

  9. Asparagine: an amide of particular distinction in the regulation of symbiotic nitrogen fixation of legumes.

    Science.gov (United States)

    Sulieman, Saad; Tran, Lam-Son Phan

    2013-09-01

    Symbiotic nitrogen fixation is tightly regulated by a range of fine processes at the nodule level, over which the host plant has overall control through the whole life of the plant. The operation of this control at the nodule level is not yet fully understood, but greater knowledge will ultimately lead to a better improvement of N2 fixation through the use of crop legumes and genetic engineering of crop plants for higher performance. It has been suggested that, nodule responses to the nutritional complexity of the rhizosphere environment involve a great deal of coordination of sensing and signal transduction. This regulation can be achieved through several mechanisms, including changes in carbon metabolism, oxygen supply and/or overproduction of reactive oxygen and nitrogen species. Recently, the cycling of amino acids observed between the plant and bacteroid fractions suggests a new and important regulatory mechanism involved in nodule responses. Most of the recent transcriptional findings are consistent with the earlier biochemical and physiological reports. Current research revealed unique advances for nodule metabolism, especially on the regulation of asparagine synthetase gene expression and the control of asparagine (ASN) to N2 fixing activity. A large amount of ASN is found accumulating in the root nodules of the symbiotic plants under restricted environments, such as drought, salinity and nutrient deficiency. Exceptionally, ASN phloem feeding has resulted in an increased concentration of the ASN amide in nodules followed by a remarkable decrease in nodule activity. In this review, recent progress concerning the possible role of ASN in whole-plant-based down-regulation of symbiotic N2 fixation will be reviewed.

  10. The fecal bacteria

    Science.gov (United States)

    Sadowsky, Michael J.; Whitman, Richard L.

    2011-01-01

    The Fecal Bacteria offers a balanced, integrated discussion of fecal bacteria and their presence and ecology in the intestinal tract of mammals, in the environment, and in the food supply. This volume covers their use in examining and assessing water quality in order to offer protection from illnesses related to swimming in or ingesting contaminated water, in addition to discussing their use in engineering considerations of water quality, modeling, monitoring, and regulations. Fecal bacteria are additionally used as indicators of contamination of ready-to-eat foods and fresh produce. The intestinal environment, the microbial community structure of the gut microbiota, and the physiology and genomics of this broad group of microorganisms are explored in the book. With contributions from an internationally recognized group of experts, the book integrates medicine, public health, environmental, and microbiological topics in order to provide a unique, holistic understanding of fecal bacteria. Moreover, it shows how the latest basic science and applied research findings are helping to solve problems and develop effective management strategies. For example, readers will discover how the latest tools and molecular approaches have led to our current understanding of fecal bacteria and enabled us to improve human health and water quality. The Fecal Bacteria is recommended for microbiologists, clinicians, animal scientists, engineers, environmental scientists, food safety experts, water quality managers, and students. It will help them better understand fecal bacteria and use their knowledge to protect human and environmental health. They can also apply many of the techniques and molecular tools discussed in this book to the study of a broad range of microorganisms in a variety of habitats.

  11. Exploring the potential of symbiotic fungal endophytes in cereal disease suppression

    DEFF Research Database (Denmark)

    O'Hanlon, Karen; Knorr, Kamilla; Jørgensen, Lise Nistrup

    2012-01-01

    Cereal crops are an essential source of nutrition worldwide. The incidence and severity of fungal diseases, in particular foliar diseases such as leaf spots, mildews and rusts, is a serious challenge to cereal production, and this problem is likely to escalate with the changing global climate......, and environmental and health concerns surrounding the use of chemical treatments. There is currently a demand for new disease control strategies, and one such strategy involves the use of symbiotic fungal endophytes as biological control agents against fungal pathogens in cereals. Despite the fact that biological...

  12. [Active oxygen species in pea seedlings during the interactions with symbiotic and pathogenic microorganisms].

    Science.gov (United States)

    Vasil'eva, G G; Glian'ko, A K; Mironova, N V; Putilina, T E; Luzova, G B

    2007-01-01

    The level of active oxygen species (AOS)--superoxide anion radical (O2*-) and hydrogen peroxide (H2O2)--in pea (Pisum sativum L.) cultivar Marat seedlings was studied upon their inoculation with symbiotic (Rhizobium leguminosarum bv. viceae strain CIAM 1026) and pathogenic (Pseudomonas syringae pv. pisi Sackett) microorganisms. Different patterns of the changes in AOS in pea seedlings during the interactions with the symbiont and the phytopathogen were recorded. It is assumed that O2*- and H2O2 are involved in the defense and regulatory mechanisms of the host plant.

  13. Kuwano's peculiar object is a novalike (symbiotic) binary with a red giant. Discussion of observational results

    International Nuclear Information System (INIS)

    Belyakina, T.S.; Gershberg, R.E.; Efimov, Yu.S.; Krasnobabtsev, V.I.; Pavlenko, E.P.; Petrov, P.P.; Chuvaev, K.K.; Shenavrin, V.I.

    1982-01-01

    Photometric, polarimetric and spectral observations carried out at the Crimea permit to conclude that the Kuwano object is a binary system that consists of an M-giant and of a low-luminosity star. During the 1979 flare, the absolute magnitude of the weak component has increased up to about -6sup(m), the M-giant had apparently small variations as well. A distance to the object is estimated to be 5-7 kpc, and it is located certainly out of the galactic plane. Similarities between the Kuwano object and slow novae and symbiotic stars are noted [ru

  14. Identification of symbiotically defective mutants of Lotus japonicus affected in infection thread growth

    DEFF Research Database (Denmark)

    Lombardo, Fabien; Heckmann, Anne Birgitte Lau; Miwa, Hiroki

    2006-01-01

    infection pockets in root hairs but form very few infection threads after inoculation with Mesorhizobium loti. The few infection threads that did initiate in the mutants usually did not progress further than the root hair cell. These infection-thread deficient (itd) mutants were unaffected for early...... symbiotic responses such as calcium spiking, root hair deformation, and curling, as well as for the induction of cortical cell division and the arbuscular mycorrhizal symbiosis. Complementation tests and genetic mapping indicate that itd2 is allelic to Ljsym7, whereas the itd1, itd3, and itd4 mutations...

  15. Chemical composition of water buffalo milk and its low-fat symbiotic yogurt development

    Directory of Open Access Journals (Sweden)

    Xue Han

    2012-04-01

    Full Text Available Background: Water buffalos are the second most widely available milk source in countries around the world. While typical average milk compositions are readily available, information on seasonal variation in chemical composition of buffalo milk is limited -especially in the Northeastern region of the United States. Data collected in this study can be useful for the manufacture of a wide variety of specialty dairy products such as symbiotic buffalo milk yogurt. To analyze functionality, symbiotic low fat buffalo milk yogurt prototypes (plain and blueberry were developed using a commercial starter containing probiotics. Methods: During a one-year cycle, physicochemical and mineral contents of buffalo milk were analyzed. Prototype yogurts were manufactured commercially and samples of the yogurt prototypes were analyzed for physicochemical and microbiological properties and for the survivability of probiotics during ten weeks of storage.Results: Average contents of total solids, fat, lactose, crude protein, ash, specific gravity, and conjugated linoleic acid in the milk ranged from 16.39-18.48%, 6.57-7.97%, 4.49-4.73%, 4.59-5.37%, 0.91-0.92%, 1.0317-1.0380%, and 4.4-7.6 mg/g fat, respectively. The average mineral contents of calcium, phosphorous, potassium, magnesium, sodium, and zinc in the milk were 1798.89, 1216.76, 843.72, 337.20 and 7.48 mg/kg, respectively, and remained steady throughout the year. The symbiotic low fat buffalo milk yogurts evaluated in this study contained higher amounts of protein, carbohydrates, and calcium than similar yogurts manufactured with cows’ milk. During refrigerated storage, the probiotic Lactobacillus acidophilus was viable (>1×106CFU/g for the first two weeks, while Bifidobacterium spp.Functional Foods in Health and Disease 2012, 2(4:86-106 and Lactobacillus casei remained viable during the entire ten weeks. Reducing the acidity and enhancing the flavor of the yogurts could improve the overall acceptability

  16. An ongoing, record-breaking outburst of the unique symbiotic binary MWC 560 = V694 Mon

    Science.gov (United States)

    Munari, U.; Righetti, G. L.; Dallaporta, S.; Moretti, S.; Graziani, M.; Valisa, P.

    2016-02-01

    The unique symbiotic binary MWC 560 = V694 Mon is on a steep rise in brightness, about to surpass the record level attained during the last - and much studied - outburst of 1990 (Tomov et al. 1990, Nature 346, 637), the brightest event in the historical light-curve of the object (Leibowitz and Formiggini 2014, AJ 150, 52). At that time MWC 560 attracted special interest by showing deep and broad absorptions, blue-shifted by 6000 km/s and completely detached from corresponding emission lines, as if originating in discrete blobs, ejected from the central star and rapidly accelerated to large velocities.

  17. Characterization of a symbiotic, heterocystous, N2-fixing cyanobacterium fromCycas coralloid roots.

    Science.gov (United States)

    Sharma, A; Mishra, D P; Kumar, A

    1992-09-01

    A symbiotic, heterocystous, N2-fixing blue-green alga, isolated from the coralloid roots of a xerophytic plant,Cycas revoluta, grew best in liquid medium supplemented with 4 mM NO 3 (-) . Morphologically, the isolated alga was identical to that of the natural endophyte but the cell size had decreased markedly. The alga was heterotrophic. Intact coralloid roots had nearly 4 to 5 times more nitrogenase activity compared with natural- and laboratory-grown agla but nitrate reductase was inducible in both the forms. Plasmid(s) were found in both algal forms.

  18. [Special effects of a complex probiotic containing cellulolytic bacteria Cellulomonas on actively growing rabbits].

    Science.gov (United States)

    Ushakova, N A; Laktionov, K S; Kozlova, A A; Ratnikova, I A; Gavrilova, N N

    2013-01-01

    It was shown that the association of probiotic bacteria of the genuses Bacillus and Cellulomonas form biolayers on the surface of beet marc particles. The positive effect of a fodder additive that contained the biolayer on the basis of a phytomatrix on the growth and development of young rabbits was shown. Feeding of animals with a mixed fodder that contained 0.1% preparation resulted in stimulation of digestion of all components of the food. Among other components of the mixed fodder, cellulose was digested most effectively. An increase in the biomass of symbiotic bacteria and enzymatic activity in the blindgut chymus was also observed. The positive nitrogen balance demonstrated an increase in the nitrogen content in animals and a decrease of its losses with excretion. The mechanism of response of the rabbit's organism to introduction of the complex probiotic preparation into the digestive tract is discussed.

  19. Effect of symbiotic interaction between a fructooligosaccharide and probiotic on the kinetic fermentation and chemical profile of maize blended rice beverages.

    Science.gov (United States)

    Freire, Ana Luiza; Ramos, Cintia Lacerda; Schwan, Rosane Freitas

    2017-10-01

    There is an important demand for the development of new non-dairy probiotic beverages in the functional food market. This work aimed to develop new fermented beverages from maize and rice. Lactobacillus plantarum CCMA 0743, Torulaspora delbrueckii CCMA 0235, and the commercial probiotic Lactobacillus acidophilus LACA 4, were used as a mixed starter culture. Two prebiotic concentrations, 20 and 50g/L fructooligosaccharide (FOS) were tested. The growth of L. acidophilus LACA 4 was favored by 50g/L FOS and after refrigerated storage at 4°C for 28days, its population remained above 10 7 CFU/mL. Lactic and acetic acids were the main organic acids detected, at around 3.7 and 0.5g/L, respectively. Ethanol was present at 50% of consumers liked slightly or liked extremely the beverages (scores from 6-9). Therefore, potential symbiotic cereal beverages were successfully obtained using a mix of lactic acid bacteria and yeast as a starter culture. This is an important step in the commercial production of alternative beverages from common food substrates for consumers. Copyright © 2017 Elsevier Ltd. All rights reserved.

  20. Effects of the Bradyrhizobium japonicum waaL (rfaL) Gene on Hydrophobicity, Motility, Stress Tolerance, and Symbiotic Relationship with Soybeans.

    Science.gov (United States)

    Noh, Jun-Gu; Jeon, Han-Eul; So, Jae-Seong; Chang, Woo-Suk

    2015-07-23

    We cloned and sequenced the waaL (rfaL) gene from Bradyrhizobium japonicum, which infects soybean and forms nitrogen-fixing nodules on soybean roots. waaL has been extensively studied in the lipopolysaccharide (LPS) biosynthesis of enteric bacteria, but little is known about its function in (brady)rhizobial LPS architecture. To characterize its role as O-antigen ligase in the LPS biosynthesis pathway, we constructed a waaL knock-out mutant and its complemented strain named JS015 and CS015, respectively. LPS analysis showed that an LPS structure of JS015 is deficient in O-antigen as compared to that of the wild type and complemented strain CS015, suggesting that WaaL ligates the O-antigen to lipid A-core oligosaccharide to form a complete LPS. JS015 also revealed increased cell surface hydrophobicity, but it showed decreased motility in soft agar plates. In addition to the alteration in cell surface properties, disruption of the waaL gene caused increased sensitivity of JS015 to hydrogen peroxide, osmotic pressure, and novobiocin. Specifically, plant tests revealed that JS015 failed to nodulate the host plant soybean, indicating that the rhizobial waaL gene is responsible for the establishment of a symbiotic relationship between soybean and B. japonicum.

  1. Grain yield, symbiotic N2 fixation and interspecific competition for inorganic N in pea-barley intercrops

    DEFF Research Database (Denmark)

    Jensen, E.S.

    1996-01-01

    g N-15-labeled N m(-2). The effect of intercropping on the dry matter and N yields, competition for inorganic N among the intercrop components, symbiotic fixation in pea and N transfer from pea to barley were determined. As an average of four years the grain yields were similar in monocropped pea...... only 9% of total fertilizer-N recovery in the intercrop. The amount of symbiotic N-2 fixation in the intercrop was less than expected from its composition and the fixation in monocrop. This indicates that the competition from barley had a negative effect on the fixation, perhaps via shading...... by the intercrop components, resulting in reduced competition for inorganic N, rather than a facilitative effect, in which symbiotically fixed N-2 is made available to barley....

  2. (C III lambda 1909/Si III lambda 1892) ratio as a diagnostic for planetary nebulae and symbiotic stars

    International Nuclear Information System (INIS)

    Feibelman, W.A.; Aller, L.H.; California Univ., Los Angeles)

    1987-01-01

    Suitable IUE archival material on planetary nebulae has been examined to determine the log R /F(lambda 1909 C III)/F(lambda 1892 Si III)/ as a discriminant for distinguishing planetary nebulae from symbiotic stars and related objects. The mean value of log R for 73 galactic planetaries is 1.4, while that of extragalactic planetaries appears to be slightly lower, and that for symbiotics is 0.3. The lower value of log R for symbiotics is easily understood as a consequence of their higher densities. A plot of log R versus N-epsilon indicates that 80 percent of the planetaries fall into the range of log R between 1.2 and 1.8, but some of the peculiar and bipolar nebulae fall below log R = 1.2. The corresponding N(C++)/N(Si++) ionic ratio varies over a large range. 53 references

  3. Symbiotic leghemoglobins are crucial for nitrogen fixation in legume root nodules but not for general plant growth and development

    DEFF Research Database (Denmark)

    Ott, Thomas; van Dongen, Joost T; Günther, Catrin

    2005-01-01

    Hemoglobins are ubiquitous in nature and among the best-characterized proteins. Genetics has revealed crucial roles for human hemoglobins, but similar data are lacking for plants. Plants contain symbiotic and nonsymbiotic hemoglobins; the former are thought to be important for symbiotic nitrogen...... accumulate to millimolar concentrations in the cytoplasm of infected plant cells prior to nitrogen fixation and are thought to buffer free oxygen in the nanomolar range, avoiding inactivation of oxygen-labile nitrogenase while maintaining high oxygen flux for respiration. Although widely accepted......RNAi plants grew normally when fertilized with mineral nitrogen. These data indicate roles for leghemoglobins in oxygen transport and buffering and prove for the first time that plant hemoglobins are crucial for symbiotic nitrogen fixation. Udgivelsesdato: 2005-Mar-29...

  4. Induced systemic resistance and symbiotic performance of peanut plants challenged with fungal pathogens and co-inoculated with the biocontrol agent Bacillus sp. CHEP5 and Bradyrhizobium sp. SEMIA6144.

    Science.gov (United States)

    Figueredo, María Soledad; Tonelli, María Laura; Ibáñez, Fernando; Morla, Federico; Cerioni, Guillermo; Del Carmen Tordable, María; Fabra, Adriana

    2017-04-01

    Synergism between beneficial rhizobacteria and fungal pathogens is poorly understood. Therefore, evaluation of co-inoculation of bacteria that promote plant growth by different mechanisms in pathogen challenged plants would contribute to increase the knowledge about how plants manage interactions with different microorganisms. The goals of this work were a) to elucidate, in greenhouse experiments, the effect of co-inoculation of peanut with Bradyrhizobium sp. SEMIA6144 and the biocontrol agent Bacillus sp. CHEP5 on growth and symbiotic performance of Sclerotium rolfsii challenged plants, and b) to evaluate field performance of these bacteria in co-inoculated peanut plants. The capacity of Bacillus sp. CHEP5 to induce systemic resistance against S. rolfsii was not affected by the inoculation of Bradyrhizobium sp. SEMIA6144. This microsymbiont, protected peanut plants from the S. rolfsii detrimental effect, reducing the stem wilt incidence. However, disease incidence in plants inoculated with the isogenic mutant Bradyrhizobium sp. SEMIA6144 V2 (unable to produce Nod factors) was as high as in pathogen challenged plants. Therefore, Bradyrhizobium sp. SEMIA6144 Nod factors play a role in the systemic resistance against S. rolfsii. Bacillus sp. CHEP5 enhanced Bradyrhizobium sp. SEMIA6144 root surface colonization and improved its symbiotic behavior, even in S. rolfsii challenged plants. Results of field trials confirmed the Bacillus sp. CHEP5 ability to protect against fungal pathogens and to improve the yield of extra-large peanut seeds from 2.15% (in Río Cuarto) to 16.69% (in Las Vertientes), indicating that co-inoculation of beneficial rhizobacteria could be a useful strategy for the peanut production under sustainable agriculture system. Copyright © 2017 Elsevier GmbH. All rights reserved.

  5. The symbiotic biofilm of Sinorhizobium fredii SMH12, necessary for successful colonization and symbiosis of Glycine max cv Osumi, is regulated by Quorum Sensing systems and inducing flavonoids via NodD1.

    Directory of Open Access Journals (Sweden)

    Francisco Pérez-Montaño

    Full Text Available Bacterial surface components, especially exopolysaccharides, in combination with bacterial Quorum Sensing signals are crucial for the formation of biofilms in most species studied so far. Biofilm formation allows soil bacteria to colonize their surrounding habitat and survive common environmental stresses such as desiccation and nutrient limitation. This mode of life is often essential for survival in bacteria of the genera Mesorhizobium, Sinorhizobium, Bradyrhizobium, and Rhizobium. The role of biofilm formation in symbiosis has been investigated in detail for Sinorhizobium meliloti and Bradyrhizobium japonicum. However, for S. fredii this process has not been studied. In this work we have demonstrated that biofilm formation is crucial for an optimal root colonization and symbiosis between S. fredii SMH12 and Glycine max cv Osumi. In this bacterium, nod-gene inducing flavonoids and the NodD1 protein are required for the transition of the biofilm structure from monolayer to microcolony. Quorum Sensing systems are also required for the full development of both types of biofilms. In fact, both the nodD1 mutant and the lactonase strain (the lactonase enzyme prevents AHL accumulation are defective in soybean root colonization. The impairment of the lactonase strain in its colonization ability leads to a decrease in the symbiotic parameters. Interestingly, NodD1 together with flavonoids activates certain quorum sensing systems implicit in the development of the symbiotic biofilm. Thus, S. fredii SMH12 by means of a unique key molecule, the flavonoid, efficiently forms biofilm, colonizes the legume roots and activates the synthesis of Nod factors, required for successfully symbiosis.

  6. Planktonic marine luminous bacteria: species distribution in the water column.

    Science.gov (United States)

    Ruby, E G; Greenberg, E P; Hastings, J W

    1980-02-01

    Luminous bacteria were isolated from oceanic water samples taken throughout the upper 1,000 m and ranged in density from 0.4 to 30 colony-forming units per 100 ml. Generally, two peaks in abundance were detected: one in the upper 100 m of the water column, which consisted primarily of Beneckea spp.; and a second between 250 and 1,000 m, which consisted almost entirely of Photobacterium phosphoreum. The population of P. phosphoreum remained relatively stable in abundance at one station that was visited three times over a period of 6 months. However, the abundance of luminous Beneckea spp. isolated from the upper waters fluctuated considerably; they were, as high as 30 colony-forming units per 100 ml in the spring and were not detected in the winter. Water samples from depths of 4,000 to 7,000 m contained less than 0.1 luminous colony-forming unit per 100 ml. The apparent vertical stratification of two taxa of oceanic luminous bacteria may reflect not only differences in physiology, but also depth-related, species-specific symbiotic associations.

  7. Differential accumulation of heavy metals in the sea anemone Anthopleura elegantissima as a function of symbiotic state

    Energy Technology Data Exchange (ETDEWEB)

    Mitchelmore, Carys L.; Alan Verde, E.; Ringwood, Amy H.; Weis, Virginia M

    2003-08-20

    The accumulation of metals by the North American Pacific Coast temperate sea anemone Anthopleura elegantissima, and its dinoflagellate-algal symbiont Symbiodinium muscatinei was examined following laboratory metal exposures. Both, naturally occurring symbiotic and symbiont-free (aposymbiotic) anemones were used in this study to investigate differences in metal uptake due to the symbiotic state of the animal. The effects of metal exposures on the anemone-algal symbiosis were determined using measures of algal cell density and mitotic index (MI). Anemones were exposed to either cadmium, copper, nickel or zinc chloride (0, 10, 100 {mu}g l{sup -1} for Cd, Cu and Ni; 0, 100, 1000 {mu}g l{sup -1} for Zn) for 42 days followed by a 42-day recovery period in ambient seawater. Anemones were analyzed for metal content using inductively coupled plasma mass spectroscopy (ICP-MS) at various time points during the study. Symbiotic anemones accumulated Cd, Ni and Zn to a greater extent than aposymbiotic anemones. A dramatically different pattern of Cu accumulation was observed, with aposymbiotic anemones accumulating higher levels than symbiotic anemones. Following recovery in ambient seawater, all tissue metal levels were reduced to near pre-exposure control levels in most cases. No changes in algal cell density or MI were observed in symbiotic anemone tentacle clips at any dose or time point in the Cd and Cu exposures. However, significant reductions in algal cell densities were observed in the Ni-exposed and some Zn-exposed animals, although levels returned to control values following recovery. There were no changes in mitotic index (MI) following Ni or Zn exposures. These results demonstrate that the extent of heavy metal accumulation depends upon cnidarian symbiotic state and the heavy metal in question.

  8. Mycorrhiza helper bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Deveau, Aurelie [French National Insitute for Agricultural Research (INRA); Labbe, Jessy [ORNL

    2016-10-01

    This chapter focuses on the Mycorrhiza Helper Bacteria (MHB), a generic name given to bacteria which stimulate the formation of mycorrhizal symbiosis. By extension, some bacterial strains that positively impact the functioning of mycorrhizal symbiosis are also called MHB. These bacteria have applicative interests, as they indirectly improve the health and growth of tree seedlings. MHB are not restricted to a specific type of ecosystem, but are rather generalist in the way that they associate with both herbaceous and woody mycorrhizal plants from boreal, temperate, arid and tropical ecosystems. However, understanding the molecular mechanisms and their specificities will help us to know more about the ecology of the MHB. The process of acquisition varies between fungal species; while ectomycorrhizal fungi most probably recurrently acquire them from the environment, the association between bacterial endosymbionts and Glomeromycota probably dates back to very ancient times, and has since been vertically transmitted.

  9. Forced symbiosis between Synechocystis spp. PCC 6803 and apo-symbiotic Paramecium bursaria as an experimental model for evolutionary emergence of primitive photosynthetic eukaryotes.

    Science.gov (United States)

    Ohkawa, Hiroshi; Hashimoto, Naoko; Furukawa, Shunsuke; Kadono, Takashi; Kawano, Tomonori

    2011-06-01

    Single-cell green paramecia (Paramecium bursaria) is a swimming vehicle that carries several hundred cells of endo-symbiotic green algae. Here, a novel model for endo-symbiosis, prepared by introducing and maintaining the cells of cyanobacterium (Synechocystis spp. PCC 6803) in the apo-symbiotic cells of P. bursaria is described.

  10. iTRAQ and RNA-Seq Analyses Provide New Insights into Regulation Mechanism of Symbiotic Germination of Dendrobium officinale Seeds (Orchidaceae).

    Science.gov (United States)

    Chen, Juan; Liu, Si Si; Kohler, Annegret; Yan, Bo; Luo, Hong Mei; Chen, Xiao Mei; Guo, Shun Xing

    2017-06-02

    Mycorrhizal fungi colonize orchid seeds and induce germination. This so-called symbiotic germination is a critical developmental process in the lifecycle of all orchid species. However, the molecular changes that occur during orchid seed symbiotic germination remain largely unknown. To better understand the molecular mechanism of orchid seed germination, we performed a comparative transcriptomic and proteomic analysis of the Chinese traditional medicinal orchid Dendrobium officinale to explore the change in protein expression at the different developmental stages during asymbiotic and symbiotic germination and identify the key proteins that regulate the symbiotic germination of orchid seeds. Among 2256 identified plant proteins, 308 were differentially expressed across three developmental stages during asymbiotic and symbiotic germination, and 229 were differentially expressed during symbiotic germination compared to asymbiotic development. Of these, 32 proteins were coup-regulated at both the proteomic and transcriptomic levels during symbiotic germination compared to asymbiotic germination. Our results suggest that symbiotic germination of D. officinale seeds shares a common signaling pathway with asymbiotic germination during the early germination stage. However, compared to asymbiotic germination, fungal colonization of orchid seeds appears to induce higher and earlier expression of some key proteins involved in lipid and carbohydrate metabolism and thus improves the efficiency of utilization of stored substances present in the embryo. This study provides new insight into the molecular basis of orchid seed germination.

  11. Soybean SAT1 (Symbiotic Ammonium Transporter 1) encodes a bHLH transcription factor involved in nodule growth and NH4+ transport

    NARCIS (Netherlands)

    Chiasson, D.M.; Loughlin, P.C.; Mazurkiewicz, D.; Mohammadidehcheshmeh, M.; Fedorova, E.E.; Okamoto, M.; McLean, E.; Glass, A.D.M.; Smith, S.E.; Bisseling, T.; Tyerman, S.D.; Day, D.A.; Kaiser, B.N.

    2014-01-01

    Glycine max symbiotic ammonium transporter 1 was first documented as a putative ammonium (NH4+) channel localized to the symbiosome membrane of soybean root nodules. We show that Glycine max symbiotic ammonium transporter 1 is actually a membrane-localized basic helix–loop–helix (bHLH) DNA-binding

  12. Laser-ablation electrospray ionization mass spectrometry with ion mobility separation reveals metabolites in the symbiotic interactions of soybean roots and rhizobia

    Energy Technology Data Exchange (ETDEWEB)

    Stopka, Sylwia A.; Agtuca, Beverly J.; Koppenaal, David W.; Pasa Tolic, Ljiljana; Stacey, Gary; Vertes, Akos; Anderton, Christopher R.

    2017-05-23

    Technologies enabling in situ metabolic profiling of living plant systems are invaluable for understanding physiological processes and could be used for rapid phenotypic screening (e.g., to produce plants with superior biological nitrogen fixing ability). The symbiotic interaction between legumes and nitrogen-fixing soil bacteria results in a specialized plant organ (i.e., root nodule), where the exchange of nutrients between host and endosymbiont occurs. Laser ablation electrospray ionization mass spectrometry (LAESI-MS) is a method that can be performed under ambient conditions requiring minimal sample preparation. Here, we employed LAESI-MS to explore the well-characterized symbiosis between soybean (Glycine max L. Merr.) and its compatible symbiont, Bradyrhizobium japonicum. The utilization of ion mobility separation (IMS) improved the molecular coverage, selectivity, and identification of the detected biomolecules. Specifically, incorporation of IMS resulted in an increase of 153 detected metabolites in the nodule samples. The data presented demonstrates the advantages of using LAESI-IMS-MS for the rapid analysis of intact root nodules, uninfected root segments, and free-living rhizobia. Untargeted pathway analysis revealed several metabolic processes within the nodule (e.g., zeatin, riboflavin, and purine synthesis). Compounds specific to the uninfected root and bacteria were also detected. Lastly, we performed depth-profiling of intact nodules to reveal the location of metabolites to the cortex and inside the infected region, and lateral profiling of sectioned nodules confirmed these molecular distributions. Our results established the feasibility of LAESI-IMS-MS for the analysis and spatial mapping of plant tissues, with its specific demonstration to improve our understanding of the soybean-rhizobial symbiosis.

  13. Oral Biofilms from Symbiotic to Pathogenic Interactions and Associated Disease –Connection of Periodontitis and Rheumatic Arthritis by Peptidylarginine Deiminase

    Directory of Open Access Journals (Sweden)

    Katja Kriebel

    2018-01-01

    Full Text Available A wide range of bacterial species are harbored in the oral cavity, with the resulting complex network of interactions between the microbiome and host contributing to physiological as well as pathological conditions at both local and systemic levels. Bacterial communities inhabit the oral cavity as primary niches in a symbiotic manner and form dental biofilm in a stepwise process. However, excessive formation of biofilm in combination with a corresponding deregulated immune response leads to intra-oral diseases, such as dental caries, gingivitis, and periodontitis. Moreover, oral commensal bacteria, which are classified as so-called “pathobionts” according to a now widely accepted terminology, were recently shown to be present in extra-oral lesions with distinct bacterial species found to be involved in the onset of various pathophysiological conditions, including cancer, atherosclerosis, chronic infective endocarditis, and rheumatoid arthritis. The present review focuses on oral pathobionts as commensal and healthy members of oral biofilms that can turn into initiators of disease. We will shed light on the processes involved in dental biofilm formation and also provide an overview of the interactions of P. gingivalis, as one of the most prominent oral pathobionts, with host cells, including epithelial cells, phagocytes, and dental stem cells present in dental tissues. Notably, a previously unknown interaction of P. gingivalis bacteria with human stem cells that has impact on human immune response is discussed. In addition to this very specific interaction, the present review summarizes current knowledge regarding the immunomodulatory effect of P. gingivalis and other oral pathobionts, members of the oral microbiome, that pave the way for systemic and chronic diseases, thereby showing a link between periodontitis and rheumatoid arthritis.

  14. Diversity and symbiotic effectiveness of indigenous rhizobia-nodulating Adesmia bicolor in soils of Central Argentina.

    Science.gov (United States)

    Bianco, Luciana; Angelini, Jorge; Fabra, Adriana; Malpassi, Rosana

    2013-02-01

    Native perennial legume Adesmia bicolor reveals characteristics that are key to securing persistence under grazing. Literature on the diversity and symbiotic effectiveness of indigenous rhizobia-nodulating A. bicolor in central Argentina is limited. The purpose of this study was therefore to determine phenotypic and genotypic variability as well as biological N-fixation effectiveness in rhizobia isolated from A. bicolor nodules. To this end, repetitive genomic regions were analyzed using ERIC primers. In the greenhouse, plants were grown under a (i) N-fertilized treatment, (ii) N-free control treatment, and (iii) rhizobia inoculation treatment. Dry weight and N-content were analyzed. All isolates belonged to Rhizobium genus and showed high symbiotic effectiveness. The N-content/subterranean N-content ratio in aerial and subterranean parts of inoculated plants was higher than that observed in N-fertilized plants during the vegetative stage. Results from this study demonstrate that symbiosis between native rhizobial strains and A. bicolor is very effective.

  15. Use of low enriched 15N2 for symbiotic fixation tests

    International Nuclear Information System (INIS)

    Victoria, R.L.

    1975-01-01

    Gaseous atmospheres containing 15 N 2 with low enrichment were used to test symbiotic nitrogen fixation in beans (Phaseolus vulgari, L.). The tests of fixation in nodulated roots and the tests of fixation in the whole plant, in which the plants were placed inside a specially constructed growth chamber, gave positive results and suggest that the methodology used can be very helpfull in more detailed studies on symbiotic fixation. Samples of atmospheric air were purified by absorption of O 2 and CO 2 by two methods. The purified N 2 obtained was analysed and the results were compared. Samples of bean plant material were collected in natural conditions and analysed for 15 N natural variation. Several samples were prepared for 15 N isotopic analysis by two methods. The results obtained were compared. All samples were analysed in an Atlas-Varian Ch-4 model mass spectrometer, and the results were given in delta 15 N 0 / 00 variation in relation to a standard gas

  16. Influence of environmental variation on symbiotic bacterial communities of two temperate sponges.

    Science.gov (United States)

    Cárdenas, César A; Bell, James J; Davy, Simon K; Hoggard, Michael; Taylor, Michael W

    2014-06-01

    Sponges are an important component of temperate subtidal marine ecosystems, with a range of important functional roles and extensive symbiotic relationships with microorganisms. However, much remains unknown about their relationships with these symbiotic microorganisms, and specifically, the role that these symbionts play in sponge physiology, feeding and adaptation to local environmental conditions. Changes in environmental factors may alter relationships between sponges and their symbionts, which could conceivably influence the abundance and distribution patterns of some temperate sponge species. Here, we analyzed the effect of transplantation of sponges between different habitats to test the effect of changes in environmental conditions on the stability of the bacterial communities in specimens of Tethya bergquistae and Ecionemia alata, based on pyrosequencing of amplified 16S rRNA genes. Bacterial communities differed markedly between the two host species. While some morphological changes were observed in transplanted sponges, transplantation had little overall effect on sponge-associated bacterial communities at either phylum or 97%-OTU level. Our results show the importance of host species and also the stability of sponge-associated bacterial communities under environmental variation. © 2014 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

  17. Simultaneous X-Ray and UV Spectroscopy of the Symbiotic HD 154791

    Science.gov (United States)

    Chakrabarty, Deepto

    2005-01-01

    Our program consisted of three observations of the symbiotic neutron stadred giant binary 4U 1700+24/HD154791. Using an earlier 2002 TOO observation made in response to a new transient X-ray outburst, we had previously discovered a redshifted O VII line and submitted a paper on this discovery to the journal Astronomy and Astrophysics. In these new observations, we from analysis of the 2002 TOO observation of the symbiotic neutron-star binary 4U 1700+24, made in response to detection of a new transient outburst, we discovered a redshifted Oxygen VIII line (in collaboration with A. Tiengo of UVA), and submitted a paper on this result to A&A. Analysis of the three subsequent observations has found a number of other features also due to ionized oxygen, which we have found to vary as the source transits from outburst to quiescence. A paper describing these observations is being prepared for submission to the Astrophysical Journal, led by Co-I Duncan Galloway.

  18. Evaluation of natural 15N abundance method in estimating symbiotic dinitrogen fixation by leguminous grasses

    International Nuclear Information System (INIS)

    Yao Yunyin; Cheng Ming; Ma Changlin; Wang Zhidong; Hou Jinqin; Zhang Lihong; Luo Yongyun

    1991-01-01

    Natural 15 N abundance method was used to estimate contribution of symbiotic dinitrogen fixation by leguminous grasses. With the method the expensive 15 N fertilizer did not need to be applied to the soil and the normal ecosystem was not disturbed. Collecting samples of shoots of leguminous grasses and measuring the content of 15 N in them wee all to do for estimating potential of symbiotically fixed N 2 . Isotopic fractionation associated with N 2 fixation by legumes was studied. Values for 7 cultivars of alfalfa were ranged between 1.0000 ∼ 1.0015 (δ 15 N values were -0.05 ∼ 1.47 per mille); and the values for white clover, mung bean and whitepopinac lead tree were 0.0079, 0.9983 and 1.0018 (δ 15 N values: 2.15, 1.74 and -1.81 per mille) respectively. According to the δ 15 N values of grasses tested, the potential of N 2 fixation for 6 cultivars of alfalfa was estimated. Glory and rambler had higher potential of N 2 fixation; Baoding, Aigonquin and Minto had lower potential, and Peru was the lowest.N 2 fixing activity of alfalfa varied with different periods. The peak was found between June and July. Effects of non-N 2 -fixing references and different methods on estimates of %Ndfa of leguminous grasses were also discussed

  19. Comparative study of the fungicide Benomyl toxicity on some plant growth promoting bacteria and some fungi in pure cultures

    Directory of Open Access Journals (Sweden)

    Elslahi Randa H.

    2014-03-01

    Full Text Available Six laboratory experiments were carried out to investigate the effect of the fungicide Benomyl on pure cultures of some plant growth promoting bacteria (PGPB and some fungi. The highest LD50 was recorded for Bacillus circulans and proved to be the most resistant to the fungicide, followed by Azospirillum braziliense, while Penicillium sp. was the most affected microorganism. LD50 values for the affected microorganisms were in 21-240 orders of magnitude lower in comparison with the LD50 value for Azospirillum braziliense. The results indicate a strong selectivity for Benomyl against Rhizobium meliloti and Penicillium sp. when compared to other microorganisms tested. The highest safety coefficient was recorded for Bacillus circulans followed by Azospirillum braziliense, while Rhizobium meliloti, showed the lowest safety coefficient value compared to other bacteria. The lowest toxicity index was recorded for Bacillus circulans and Azospirillum braziliense. The slope of the curves for Bacillus sp. and Rhizobium meliloti was steeper than that of the other curves, suggesting that even a slight increase of the dose of the fungicide can cause a very strong negative effect. In conclusion, Benomyl could be applied without restriction when using inocula based on growth promoting bacteria such as symbiotic nitrogen fixers (Rhizobium meliloti, non-symbiotic nitrogen fixers (Azospirillum braziliense or potassium solibilizers (Bacillus circulans, given that the fungicide is applied within the range of the recommended field dose.

  20. Marine sponge-associated bacteria as a potential source for polyhydroxyalkanoates.

    Science.gov (United States)

    Sathiyanarayanan, Ganesan; Saibaba, Ganesan; Kiran, George Seghal; Yang, Yung-Hun; Selvin, Joseph

    2017-05-01

    Marine sponges are filter feeding porous animals and usually harbor a remarkable array of microorganisms in their mesohyl tissues as transient and resident endosymbionts. The marine sponge-microbial interactions are highly complex and, in some cases, the relationships are thought to be truly symbiotic or mutualistic rather than temporary associations resulting from sponge filter-feeding activity. The marine sponge-associated bacteria are fascinating source for various biomolecules that are of potential interest to several biotechnological industries. In recent times, a particular attention has been devoted to bacterial biopolymer (polyesters) such as intracellular polyhydroxyalkanoates (PHAs) produced by sponge-associated bacteria. Bacterial PHAs act as an internal reserve for carbon and energy and also are a tremendous alternative for fossil fuel-based polymers mainly due to their eco-friendliness. In addition, PHAs are produced when the microorganisms are under stressful conditions and this biopolymer synthesis might be exhibited as one of the survival mechanisms of sponge-associated or endosymbiotic bacteria which exist in a highly competitive and stressful sponge-mesohyl microenvironment. In this review, we have emphasized the industrial prospects of marine bacteria for the commercial production of PHAs and special importance has been given to marine sponge-associated bacteria as a potential resource for PHAs.

  1. Symbiotic Networks

    NARCIS (Netherlands)

    Pieters, C.P.

    2008-01-01

    Research of evolution theory has boomed in the last decade, and has caused a significant differentiation of the classic, 'machismo' view on Darwinism, in which nature is considered to be an arena where organisms continuously struggle for survival in fierce competition. The three 'soft' forces in

  2. Antifreeze Proteins of Bacteria

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 12. Antifreeze Proteins of Bacteria. M K Chattopadhyay. General Article Volume 12 Issue 12 December 2007 pp 25-30. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/012/12/0025-0030 ...

  3. (PHB)-producing bacteria

    African Journals Online (AJOL)

    Jane

    2011-06-06

    Jun 6, 2011 ... Bioplastics are naturally occurring biodegradable polymers made from polyhydroxyalkanoates (PHA) of which poly 3-hydroxy butyric acid ... The plastic polymers accumulate intracellularly as light- refracting amorphous ... study focuses on the isolation and identification of novel species of bacteria capable ...

  4. Do Bacteria Age?

    Indian Academy of Sciences (India)

    Bacteria are thought to be examples of organisms that do not age. ... sues, organs, organ systems, organism, population, species, and .... Humans inevitably grow old through aging. All vertebrates show physical manifestations of aging somewhat similar to humans (other than white hair!). Aging is also seen in plants.

  5. Antifreeze Proteins of Bacteria

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 12; Issue 12. Antifreeze Proteins of Bacteria. M K Chattopadhyay. General Article Volume 12 Issue 12 December 2007 pp 25-30. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/012/12/0025-0030. Keywords.

  6. Antibiotic-Resistant Bacteria.

    Science.gov (United States)

    Longenecker, Nevin E.; Oppenheimer, Dan

    1982-01-01

    A study conducted by high school advanced bacteriology students appears to confirm the hypothesis that the incremental administration of antibiotics on several species of bacteria (Escherichia coli, Staphylococcus epidermis, Bacillus sublitus, Bacillus megaterium) will allow for the development of antibiotic-resistant strains. (PEB)

  7. (PHB)-producing bacteria

    African Journals Online (AJOL)

    Isolation and characterization of two novel polyhydroxybutyrate (PHB)-producing bacteria. ... subsequently studied using phenotype microarray panels which allowed the testing of the effect of more than 90 different carbon, nitrogen, sulfur and phosphorus sources as well as pH on the growth characteristics of these strains.

  8. The 26th anniversary outburst of jet-driving symbiotic binary MWC 560: results from Chandra, Swift, and optical spectroscopy

    Science.gov (United States)

    Lucy, Adrian B.; Sokoloski, J. L.; Munari, U.; Kuin, N. P. M.; Darnley, M. J.; Luna, G. J. M.; Knigge, C.; Valisa, P.; Milani, A.

    2016-03-01

    The symbiotic star MWC 560 = V694 Mon, which is believed to usually drive a jet along the line of sight (e.g., Schmid et al. 2001), is undergoing a sustained outburst (ATel #8653) rivaling its previous brightest outburst of 1990 (Tomov et al. 1990, Leibowitz and Formiggini 2015).

  9. Feather mite abundance varies but symbiotic nature of mite-host relationship does not differ between two ecologically dissimilar warblers

    Science.gov (United States)

    Alix E. Matthews; Jeffery L. Larkin; Douglas W. Raybuck; Morgan C. Slevin; Scott H. Stoleson; Than J. Boves

    2017-01-01

    Feather mites are obligatory ectosymbionts of birds that primarily feed on the oily secretions from the uropygial gland. Feather mite abundance varies within and among host species and has various effects on host condition and fitness, but there is little consensus on factors that drive variation of this symbiotic system. We tested hypotheses regarding how within-...

  10. Strigolactone Biosynthesis in Medicago truncatula and Rice Requires the Symbiotic GRAS-Type Transcription Factors NSP1 and NSP2

    NARCIS (Netherlands)

    Liu, W.; Kohlen, W.; Lillo, A.; Camp, op den R.; Ivanov, S.; Hartog, M.; Limpens, E.H.M.; Jamil, M.; Smaczniak, C.; Kaufmann, K.; Yang, W.C.; Hooiveld, G.J.E.J.; Charnikhova, T.; Bouwmeester, H.J.; Bisseling, T.; Geurts, R.

    2011-01-01

    Legume GRAS (GAI, RGA, SCR)-type transcription factors NODULATION SIGNALING PATHWAY1 (NSP1) and NSP2 are essential for rhizobium Nod factor-induced nodulation. Both proteins are considered to be Nod factor response factors regulating gene expression after symbiotic signaling. However, legume NSP1

  11. Adaptive evolution of the symbiotic gene NORK is not correlated with shifts of rhizobial specificity in the genus Medicago

    NARCIS (Netherlands)

    Mita, De S.; Santoni, S.; Ronfort, J.; Bataillon, T.

    2007-01-01

    The NODULATION RECEPTOR KINASE (NORK) gene encodes a Leucine-Rich Repeat (LRR)-containing receptor-like protein and controls the infection by symbiotic rhizobia and endomycorrhizal fungi in Legumes. The occurrence of numerous amino acid changes driven by directional selection has been reported in

  12. Genetic Factors in Rhizobium Affecting the Symbiotic Carbon Costs of N2 Fixation and Host Plant Biomass Production

    DEFF Research Database (Denmark)

    Skøt, L.; Hirsch, P. R.; Witty, J. F.

    1986-01-01

    The effect of genetic factors in Rhizobium on host plant biomass production and on the carbon costs of N2 fixation in pea root nodules was studied. Nine strains of Rhizobium leguminosarum were constructed, each containing one of three symbiotic plasmids in combination with one of three different...

  13. Uptake and specification of selenium in garlic cultivated in soil amended with symbiotic fungi (mycorrhiza) and selenate

    NARCIS (Netherlands)

    Larsen, E.H.; Lobinski, R.; Burger-Meijer, K.; Hansen, M.; Ruzik, R.; Mazurowska, L.; Rasmussen, P.H.; Sloth, J.J.; Scholten, O.E.; Kik, C.

    2006-01-01

    The scope of the work was to investigate the influence of selenate fertilisation and the addition of symbiotic fungi (mycorrhiza) to soil on selenium and selenium species concentrations in garlic. The selenium species were extracted from garlic cultivated in experimental plots by proteolytic

  14. The friendly bacteria within us Commensal bacteria of the intestine ...

    Indian Academy of Sciences (India)

    The friendly bacteria within us Commensal bacteria of the intestine: Roles in health and disease B.S. Ramakrishna Professor & Head Gastroenterology & Hepatology Christian Medical College Vellore · Slide 2 · Intestinal bacteria: the hidden organ · Slide 4 · Slide 5 · The normal bacterial flora prevents GI disease · Slide 7.

  15. The friendly bacteria within us Commensal bacteria of the intestine ...

    Indian Academy of Sciences (India)

    Short chain fatty acids (SCFA) are main source of energy for colonic epithelial cells · SCFA – role in colonic disease · SCFA prevent mucosal inflammation · Immunoregulation by gut bacteria · Balance of bacterial species in the gut · Immunosensory detection of intestinal bacteria · Pathogenic bacteria release interleukin-8 ...

  16. Manufacture of Probiotic Bacteria

    Science.gov (United States)

    Muller, J. A.; Ross, R. P.; Fitzgerald, G. F.; Stanton, C.

    Lactic acid bacteria (LAB) have been used for many years as natural biopreservatives in fermented foods. A small group of LAB are also believed to have beneficial health effects on the host, so called probiotic bacteria. Probiotics have emerged from the niche industry from Asia into European and American markets. Functional foods are one of the fastest growing markets today, with estimated growth to 20 billion dollars worldwide by 2010 (GIA, 2008). The increasing demand for probiotics and the new food markets where probiotics are introduced, challenges the industry to produce high quantities of probiotic cultures in a viable and stable form. Dried concentrated probiotic cultures are the most convenient form for incorporation into functional foods, given the ease of storage, handling and transport, especially for shelf-stable functional products. This chapter will discuss various aspects of the challenges associated with the manufacturing of probiotic cultures.

  17. Bacteria in ulcera crurum.

    Science.gov (United States)

    Kontiainen, S; Rinne, E

    1988-01-01

    Bacterial cultures derived from 432 chronic leg ulcers were analysed retrospectively to determine which bacteria are most commonly found in these ulcers. The study covered a 2-year period. Two-thirds of the patients were over 70 years of age. Staphylococcus aureus was found in nearly half of the ulcers studied, Pseudomonas sp. in one-third, pyogenic streptococci and enterococci in every fifth and Proteus sp. in every tenth. The frequency by which pyogenic streptococci were isolated was about 10 to 20 times as high as previously reported. Obligate anaerobic bacteria were also frequently isolated. The sensitivity of the isolates from the second year to antimicrobial agents likely to be chosen if systemic therapy were required is also reported. The results are discussed in relation to previous findings.

  18. Selective isolation of potentially phosphate-mobilizing, biosurfactant-producing and biodegradative bacteria associated with a sub-Arctic, terricolous lichen, Peltigera membranacea.

    Science.gov (United States)

    Sigurbjörnsdóttir, Margrét Auður; Vilhelmsson, Oddur

    2016-06-01

    Lichens are the symbiotic association of fungi and a photosynthetic partner. However, non-phototrophic bacteria are also present and thought to comprise an essential part of the lichen symbiosis, although their roles in the symbiosis are still poorly understood. In this study, we isolated and characterized 110 non-phototrophic bacterial lichen associates from thalli of the terricolous lichen Peltigera membranacea The biodegradative and other nutrient-scavenging properties studied among selected isolates were phosphate mobilization, biosurfactant production and degradation of napthalene and several biopolymers, suggesting organic and inorganic nutrient scavenging as roles for bacteria in the lichen symbiotic association. Identification by partial 16S rRNA gene sequencing revealed that the isolates comprised 18 genera within the Proteobacteria, Actinobacteria, Bacteroidetes and Firmicutes, many with high similarities with bacteria typically associated with the plant and rhizosphere environments, could suggest that plants may be important sources of terricolous lichen-associated bacteria, or vice versa. © FEMS 2016. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  19. Bacteria in ancient sediments

    International Nuclear Information System (INIS)

    Izzo, G.

    1986-01-01

    In order to ascertain the role of biological activity in ancient sediments, two microbiological studies were carried out. The first was on pleistocenic clay sediments on land, the second on deep oceanic sediments. In the present paper by direct counting the samples is demonstrated the presence of bacteria in a range of 10 5 to 10 7 . Further studies must be carried out to ascertain the activities by in situ incubation methods

  20. Bacteria colonizing paper machines

    OpenAIRE

    Ekman, Jaakko

    2011-01-01

    Bacteria growing in paper machines can cause several problems. Biofilms detaching from paper machine surfaces may lead to holes and spots in the end product or even break the paper web leading to expensive delays in production. Heat stable endospores will remain viable through the drying section of paper machine, increasing the microbial contamination of paper and board. Of the bacterial species regularly found in the end products, Bacillus cereus is the only one classified as a pathogen. Cer...

  1. Symbiotic specificity, association patterns, and function determine community responses to global changes: defining critical research areas for coral-Symbiodinium symbioses.

    Science.gov (United States)

    Fabina, Nicholas S; Putnam, Hollie M; Franklin, Erik C; Stat, Michael; Gates, Ruth D

    2013-11-01

    Climate change-driven stressors threaten the persistence of coral reefs worldwide. Symbiotic relationships between scleractinian corals and photosynthetic endosymbionts (genus Symbiodinium) are the foundation of reef ecosystems, and these associations are differentially impacted by stress. Here, we couple empirical data from the coral reefs of Moorea, French Polynesia, and a network theoretic modeling approach to evaluate how patterns in coral-Symbiodinium associations influence community stability under climate change. To introduce the effect of climate perturbations, we simulate local 'extinctions' that represent either the loss of coral species or the ability to engage in symbiotic interactions. Community stability is measured by determining the duration and number of species that persist through the simulated extinctions. Our results suggest that four factors greatly increase coral-Symbiodinium community stability in response to global changes: (i) the survival of generalist hosts and symbionts maximizes potential symbiotic unions; (ii) elevated symbiont diversity provides redundant or complementary symbiotic functions; (iii) compatible symbiotic assemblages create the potential for local recolonization; and (iv) the persistence of certain traits associate with symbiotic diversity and redundancy. Symbiodinium may facilitate coral persistence through novel environmental regimes, but this capacity is mediated by symbiotic specificity, association patterns, and the functional performance of the symbionts. Our model-based approach identifies general trends and testable hypotheses in coral-Symbiodinium community responses. Future studies should consider similar methods when community size and/or environmental complexity preclude experimental approaches. © 2013 John Wiley & Sons Ltd.

  2. Bipolar ejection by the symbiotic binary system Z And during its 2006 outburst

    Science.gov (United States)

    Tomov, N. A.; Tomova, M. T.; Bisikalo, D. V.

    2007-03-01

    High-resolution data in the region of the Hα line have been obtained at the time of light maximum and after it for the 2006 optical outburst of the symbiotic binary Z And. A blueshifted absorption component indicating an outflow velocity of about 1400 km s-1, as well as additional emission components with similar velocities, situated on the two sides of the main peak of the line, were observed during that time. It is suggested that all of them are spectral signatures of bipolar outflow, observed for the first time in the optical spectrum of this binary. The emission measure and the mass of the nebular part of the streams have been estimated approximately, reaching values of up to about 6 × 1057 cm-3 and 8 × 10-8Msolar. Based on observations collected at the National Astronomical Observatory Rozhen, Bulgaria. E-mail: tomov@astro.bas.bg

  3. Cultivar and Rhizobium Strain Effects on the Symbiotic Performance of Pea (Pisum sativum)

    DEFF Research Database (Denmark)

    Skøt, Leif

    1983-01-01

    The symbiotic performance of four pea (Pisum sativum L.) cultivars in combination with each of four strains of Rhizobium leguminosarum was studied in growth chamber experiments in order to estimate the effects of cultivars, strains and cultivar × strain interaction on the variation in dry weight, N...... content and dry weight/N ratio. At harvest 63 days after planting, cultivars accounted for 75% of the variation in dry weight, while the Rhizobium strains accounted for 63% of the variation in N-content and 70% of the variation in dry weight/N ratio. Cultivar × strain interactions were statistically...... significant, but of minor quantitative importance, accounting for 5–15% of the total variation. Rhizobium strains also influenced the partitioning of N between reproductive and vegetative plant parts and between root and shoot biomass....

  4. A D'-type symbiotic binary in the planetary nebula SMP LMC 88

    Science.gov (United States)

    Iłkiewicz, Krystian; Mikołajewska, Joanna; Miszalski, Brent; Kozłowski, Szymon; Udalski, Andrzej

    2018-05-01

    SMP LMC 88 is one of the planetary nebulae (PNe) in the Large Magellanic Cloud. We identify in its spectrum Raman scattered O VI lines at 6825 and 7083 Å. This unambiguously classifies the central object of the nebula as a symbiotic star (SySt). We identified the cold component to be a K-type giant, making this the first D'-type (yellow) SySt discovered outside the Galaxy. The photometric variability in SMP LMC 88 resembles the orbital variability of Galactic D'-type SySt with its low amplitude and sinusoidal light-curve shape. The SySt classification is also supported by the He I diagnostic diagram.

  5. Antigenic similarities and differences between symbiotic and cultured phycobionts from the lichen, Xanthoria parietina

    International Nuclear Information System (INIS)

    Bubrick, P.; Galun, M.; Ben-Yaacov, M.; Frensdorff, A.

    1982-01-01

    Lichen phycobionts are known to undergo a series of morphological, physiological, and biochemical changes as a result of lichenization. A number of modifications in the cell wall of lichen algae have also been described. Using the phycobiont of Xanthoria parietina as a study organism. The authors have shown that concanavalin A bound to the cell wall of lichen algae cultured in vitro, but not to the same algae in the symbiotic form (freshly isolated from the lichen). They have also isolated a crude protein fraction from the lichen, a component(s) of which bound to the cell wall of cultured, but not freshly isolated algae. Binding was correlated to cytochemical features present only on the cell wall of cultured algae. With the aid of a newly-developed solid-phase radioimmunoassay, the authors show that there are also detectable antigenic differences, as well as similarities, between freshly isolated and cultured phycobionts from X. parietina. (Auth.)

  6. When a repellent becomes an attractant: harmful saponins are kairomones attracting the symbiotic Harlequin crab.

    Science.gov (United States)

    Caulier, Guillaume; Flammang, Patrick; Gerbaux, Pascal; Eeckhaut, Igor

    2013-01-01

    Marine organisms have developed a high diversity of chemical defences in order to avoid predators and parasites. In sea cucumbers, saponins function as repellents and many species produce these cytotoxic secondary metabolites. Nonetheless, they are colonized by numerous symbiotic organisms amongst which the Harlequin crab, Lissocarcinus orbicularis, is one of the most familiar in the Indo-Pacific Ocean. We here identify for the first time the nature of the molecules secreted by sea cucumbers and attracting the symbionts: saponins are the kairomones recognized by the crabs and insuring the symbiosis. The success of this symbiosis would be due to the ability that crabs showed during evolution to bypass the sea cucumber chemical defences, their repellents becoming powerful attractants. This study therefore highlights the complexity of chemical communication in the marine environment.

  7. Symbiotic nitrogen fixation in an arid ecosystem measured by sup 15 N natural abundance

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, G.V. (Univ. of New Mexico, Albuquerque (USA))

    1990-05-01

    Plants dependent on nitrogen fixation have an {sup 15}N abundance similar to the atmosphere, while non-nitrogen fixing plants usually are enriched in {sup 15}N and are similar to soil nitrogen values. The natural abundance of {sup 15}N in leaf tissues and soils was determined to evaluate symbiotic nitrogen fixation by several legumes and actinorhizal species in the Sevilleta Long-term Ecological Research area in central New Mexico. Comparison of {delta}{sup 15}N values for the legume Prosopis glandulosa (mesquite) to adjacent Atriplex canascens (fourwing saltbush) indicated that P. glandulosa obtained 66% of its nitrogen by fixation. The legume Hoffmanseggia jamesii was found to be utilizing soil nitrogen. The {delta}{sup 15}N values for the actinorhizal plants, Elaeagnus angustifolia and Cercocarpus montanus, while below values for soil nitrogen, did not differ from associated non-fixing plants.

  8. PTF 11kx: a type Ia supernova with a symbiotic nova progenitor.

    Science.gov (United States)

    Dilday, B; Howell, D A; Cenko, S B; Silverman, J M; Nugent, P E; Sullivan, M; Ben-Ami, S; Bildsten, L; Bolte, M; Endl, M; Filippenko, A V; Gnat, O; Horesh, A; Hsiao, E; Kasliwal, M M; Kirkman, D; Maguire, K; Marcy, G W; Moore, K; Pan, Y; Parrent, J T; Podsiadlowski, P; Quimby, R M; Sternberg, A; Suzuki, N; Tytler, D R; Xu, D; Bloom, J S; Gal-Yam, A; Hook, I M; Kulkarni, S R; Law, N M; Ofek, E O; Polishook, D; Poznanski, D

    2012-08-24

    There is a consensus that type Ia supernovae (SNe Ia) arise from the thermonuclear explosion of white dwarf stars that accrete matter from a binary companion. However, direct observation of SN Ia progenitors is lacking, and the precise nature of the binary companion remains uncertain. A temporal series of high-resolution optical spectra of the SN Ia PTF 11kx reveals a complex circumstellar environment that provides an unprecedentedly detailed view of the progenitor system. Multiple shells of circumstellar material are detected, and the SN ejecta are seen to interact with circumstellar material starting 59 days after the explosion. These features are best described by a symbiotic nova progenitor, similar to RS Ophiuchi.

  9. Global changes in transcription orchestrate metabolic differentiation during symbiotic nitrogen fixation in Lotus japonicus

    DEFF Research Database (Denmark)

    Colebatch, Gillian; Desbrosses, Guilhem; Ott, Thomas

    2004-01-01

    from specific sets of induced genes. In addition to the expected signs of hypoxia, numerous indications were obtained that nodule cells also experience P-limitation and osmotic stress. Several potential regulators of these stress responses were identified. Metabolite profiling by gas chromatography......Research on legume nodule metabolism has contributed greatly to our knowledge of primary carbon and nitrogen metabolism in plants in general, and in symbiotic nitrogen fixation in particular. However, most previous studies focused on one or a few genes/enzymes involved in selected metabolic...... pathways in many different legume species. We utilized the tools of transcriptomics and metabolomics to obtain an unprecedented overview of the metabolic differentiation that results from nodule development in the model legume, Lotus japonicus. Using an array of more than 5000 nodule cDNA clones...

  10. The symbiotic star CI Cygni: S-process episode or accretion event

    International Nuclear Information System (INIS)

    Kenyon, S.J.; Webbink, R.F.; Gallagher, J.S.; Truran, J.W.

    1982-01-01

    Evidence that the symbiotic star C I Cygni is an eclipsing binary is reviewed. It is shown that the 's-process episode' described by Audouze et al. (1981) during its 1975 outburst arises from superposition of normal gM4 absorption features on the continuum of the hot component during eclipse ingress, and not to sudden enhancements of rare earth elements. The peculiar velocity displacements of absorption lines with different excitation potentials during this episode are identified as signatures of an optically thick accretion disk, which dominates the visible spectrum during outburst. The data presented by Audouze et al., and the shape of the light curve thus provide evidence that the outburst is accretion-powered. (orig.)

  11. Drought enhances symbiotic dinitrogen fixation and competitive ability of a temperate forest tree.

    Science.gov (United States)

    Wurzburger, Nina; Miniat, Chelcy Ford

    2014-04-01

    General circulation models project more intense and frequent droughts over the next century, but many questions remain about how terrestrial ecosystems will respond. Of particular importance, is to understand how drought will alter the species composition of regenerating temperate forests wherein symbiotic dinitrogen (N2)-fixing plants play a critical role. In experimental mesocosms we manipulated soil moisture to study the effect of drought on the physiology, growth and competitive interactions of four co-occurring North American tree species, one of which (Robinia pseudoacacia) is a symbiotic N2-fixer. We hypothesized that drought would reduce growth by decreasing stomatal conductance, hydraulic conductance and increasing the water use efficiency of species with larger diameter xylem vessel elements (Quercus rubra, R. pseudoacacia) relative to those with smaller elements (Acer rubrum and Liriodendron tulipifera). We further hypothesized that N2 fixation by R. pseudoacacia would decline with drought, reducing its competitive ability. Under drought, growth declined across all species; but, growth and physiological responses did not correspond to species' hydraulic architecture. Drought triggered an 80% increase in nodule biomass and N accrual for R. pseudoacacia, improving its growth relative to other species. These results suggest that drought intensified soil N deficiency and that R. pseudoacacia's ability to fix N2 facilitated competition with non-fixing species when both water and N were limiting. Under scenarios of moderate drought, N2 fixation may alleviate the N constraints resulting from low soil moisture and improve competitive ability of N2-fixing species, and as a result, supply more new N to the ecosystem.

  12. Thiazolidinedione-8 alters symbiotic relationship in C. albicans-S. mutans dual species biofilm

    Directory of Open Access Journals (Sweden)

    Mark eFeldman

    2016-02-01

    Full Text Available The small molecule, thiazolidinedione-8 (S-8 was shown to impair biofilm formation of various microbial pathogens, including the fungus Candida albicans and Streptococcus mutans. Previously, we have evaluated the specific molecular mode of S-8 action against C. albicans biofilm-associated pathogenicity. In this study we investigated the influence of S-8 on dual species, C. albicans-S. mutans biofilm. We show that in the presence of S-8 a reduction of the co-species biofilm formation occurred with a major effect on C. albicans. Biofilm biomass and exopolysaccharide (EPS production were significantly reduced by S-8. Moreover, the agent caused oxidative stress associated with a strong induction of reactive oxygen species (ROS and hydrogen peroxide uptake inhibition by a mixed biofilm. In addition, S-8 altered symbiotic relationship between these species by a complex mechanism. Streptococcal genes associated with quorum sensing (comDE and luxS, EPS production (gtfBCD and gbpB, as well as genes related to protection against oxidative stress (nox and sodA were markedly upregulated by S-8. In contrast, fungal genes related to hyphae formation (hwp1, adhesion (als3, hydrophobicity (csh1 and oxidative stress response (sod1, sod2 and cat1 were downregulated in the presence of S-8. In addition, ywp1 gene associated with yeast form of C. albicans was induced by S-8, which is correlated with appearance of mostly yeast cells in S-8 treated dual species biofilms. We concluded that S-8 disturbs symbiotic balance between C. albicans and S. mutans in dual species biofilm.

  13. Symbiotic intelligence: Self-organizing knowledge on distributed networks, driven by human interaction

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, N.; Joslyn, C.; Rocha, L.; Smith, S.; Kantor, M. [Los Alamos National Lab., NM (United States); Rasmussen, S. [Los Alamos National Lab., NM (United States)]|[Santa Fe Inst., NM (United States)

    1998-07-01

    This work addresses how human societies, and other diverse and distributed systems, solve collective challenges that are not approachable from the level of the individual, and how the Internet will change the way societies and organizations view problem solving. The authors apply the ideas developed in self-organizing systems to understand self-organization in informational systems. The simplest explanation as to why animals (for example, ants, wolves, and humans) are organized into societies is that these societies enhance the survival of the individuals which make up the populations. Individuals contribute to, as well as adapt to, these societies because they make life easier in one way or another, even though they may not always understand the process, either individually or collectively. Despite the lack of understanding of the how of the process, society during its existence as a species has changed significantly, from separate, small hunting tribes to a highly technological, globally integrated society. The authors combine this understanding of societal dynamics with self-organization on the Internet (the Net). The unique capability of the Net is that it combines, in a common medium, the entire human-technological system in both breadth and depth: breadth in the integration of heterogeneous systems of machines, information and people; and depth in the detailed capturing of the entire complexity of human use and creation of information. When the full diversity of societal dynamics is combined with the accuracy of communication on the Net, a phase transition is argued to occur in problem solving capability. Through conceptual examples, an experiment of collective decision making on the Net and a simulation showing the effect of noise and loss on collective decision making, the authors argue that the resulting symbiotic structure of humans and the Net will evolve as an alternative problem solving approach for groups, organizations and society. Self

  14. In silico insights into the symbiotic nitrogen fixation in Sinorhizobium meliloti via metabolic reconstruction.

    Science.gov (United States)

    Zhao, Hansheng; Li, Mao; Fang, Kechi; Chen, Wenfeng; Wang, Jing

    2012-01-01

    Sinorhizobium meliloti is a soil bacterium, known for its capability to establish symbiotic nitrogen fixation (SNF) with leguminous plants such as alfalfa. S. meliloti 1021 is the most extensively studied strain to understand the mechanism of SNF and further to study the legume-microbe interaction. In order to provide insight into the metabolic characteristics underlying the SNF mechanism of S. meliloti 1021, there is an increasing demand to reconstruct a metabolic network for the stage of SNF in S. meliloti 1021. Through an iterative reconstruction process, a metabolic network during the stage of SNF in S. meliloti 1021 was presented, named as iHZ565, which accounts for 565 genes, 503 internal reactions, and 522 metabolites. Subjected to a novelly defined objective function, the in silico predicted flux distribution was highly consistent with the in vivo evidences reported previously, which proves the robustness of the model. Based on the model, refinement of genome annotation of S. meliloti 1021 was performed and 15 genes were re-annotated properly. There were 19.8% (112) of the 565 metabolic genes included in iHZ565 predicted to be essential for efficient SNF in bacteroids under the in silico microaerobic and nutrient sharing condition. As the first metabolic network during the stage of SNF in S. meliloti 1021, the manually curated model iHZ565 provides an overview of the major metabolic properties of the SNF bioprocess in S. meliloti 1021. The predicted SNF-required essential genes will facilitate understanding of the key functions in SNF and help identify key genes and design experiments for further validation. The model iHZ565 can be used as a knowledge-based framework for better understanding the symbiotic relationship between rhizobia and legumes, ultimately, uncovering the mechanism of nitrogen fixation in bacteroids and providing new strategies to efficiently improve biological nitrogen fixation.

  15. Further data on the effects of subliminal symbiotic stimulation on schizophrenics.

    Science.gov (United States)

    Kaplan, R; Thornton, P; Silverman, L

    1985-11-01

    This investigation further examined the effects of activating unconscious symbiotic fantasies in schizophrenics. One hundred twenty-eight hospitalized schizophrenic men who qualified as "relatively differentiated" on the Adjective Rating Scale were randomly assigned to four groups. Each group was assessed for pathological thinking, pathological nonverbal behavior, and self-esteem before and after the subliminal exposure of an experimental and control stimulus. The control stimulus for all groups was the message PEOPLE ARE WALKING and the experimental stimuli were the messages MOMMY AND I ARE ONE, MOMMY IS ALWAYS WITH ME, MOMMY FEEDS ME WELL, and I CANNOT HURT MOMMY (one for each group). One half of each group was subliminally exposed to verbal messages only and one half to verbal messages accompanied by congruent pictures. The first stimulus (MOMMY AND I ARE ONE) was intended to activate unconscious symbiotic fantasies that in a number of prior studies reduced pathology in groups of relatively differentiated schizophrenics. The other stimuli were intended to activate reassuring unconscious fantasies about "mommy" that were not specifically symbiosis-related. Only the MOMMY AND I ARE ONE stimulus led to more adaptive behavior and did so on all three dependent variables. This supported the supposition, also borne out in two other studies, that it is specifically symbiosis-related gratifications that are ameliorative for schizophrenics. The above results were considerably stronger for the subgroup that was exposed to a picture accompanying the MOMMY AND I ARE ONE message. This was viewed as probably the result of the pictorial representation serving as a concretization of the more abstract verbal message and as such being more relevant to the relatively primitive mode of thinking in schizophrenia.

  16. New Developments in Actinides Burning with Symbiotic LWR-HTR-GCFR Fuel Cycles

    International Nuclear Information System (INIS)

    Bomboni, Eleonora

    2008-01-01

    The long-term radiotoxicity of the final waste is currently the main drawback of nuclear power production. Particularly, isotopes of Neptunium and Plutonium along with some long-lived fission products are dangerous for more than 100000 years. 96% of spent Light Water Reactor (LWR) fuel consists of actinides, hence it is able to produce a lot of energy by fission if recycled. Goals of Generation IV Initiative are reduction of long-term radiotoxicity of waste to be stored in geological repositories, a better exploitation of nuclear fuel resources and proliferation resistance. Actually, all these issues are intrinsically connected with each other. It is quite clear that these goals can be achieved only by combining different concepts of Gen. IV nuclear cores in a 'symbiotic' way. Light-Water Reactor - (Very) High Temperature Reactor ((V)HTR) - Fast Reactor (FR) symbiotic cycles have good capabilities from the viewpoints mentioned above. Particularly, HTR fuelled by Plutonium oxide is able to reach an ultra-high burn-up and to burn Neptunium and Plutonium effectively. In contrast, not negligible amounts of Americium and Curium build up in this core, although the total mass of Heavy Metals (HM) is reduced. Americium and Curium are characterised by an high radiological hazard as well. Nevertheless, at least Plutonium from HTR (rich in non-fissile nuclides) and, if appropriate, Americium can be used as fuel for Fast Reactors. If necessary, dedicated assemblies for Minor Actinides (MA) burning can be inserted in Fast Reactors cores. This presentation focuses on combining HTR and Gas Cooled Fast Reactor (GCFR) concepts, fuelled by spent LWR fuel and depleted uranium if need be, to obtain a net reduction of total mass and radiotoxicity of final waste. The intrinsic proliferation resistance of this cycle is highlighted as well. Additionally, some hints about possible Curium management strategies are supplied. Besides, a preliminary assessment of different chemical forms of

  17. Essential oils affect populations of some rumen bacteria in vitro as revealed by microarray (RumenBactArray analysis

    Directory of Open Access Journals (Sweden)

    Amlan Kumar Patra

    2015-04-01

    Full Text Available In a previous study origanum oil (ORO, garlic oil (GAO, and peppermint oil (PEO were shown to effectively lower methane production, decrease abundance of methanogens, and change abundances of several bacterial populations important to feed digestion in vitro. In this study, the impact of these essential oils (EOs, at 0.50 g/L, on the rumen bacterial community composition and population was further examined using the recently developed RumenBactArray. Species richness (expressed as number of operational taxonomic units, OTUs in the phylum Firmicutes, especially those in the class Clostridia, was decreased by ORO and GAO, but increased by PEO, while that in the phylum Bacteroidetes was increased by ORO and PEO. Species richness in the genus Butyrivibrio was lowered by all the EOs. Increases of Bacteroidetes OTUs mainly resulted from increases of Prevotella OTUs. Overall, 67 individual OTUs showed significant differences (P≤0.05 in relative abundance across the EO treatments. The predominant OTUs affected by EOs were diverse, including those related to Syntrophococcus sucromutans, Succiniclasticum ruminis, and Lachnobacterium bovis, and those classified to Prevotella, Clostridium, Roseburia, Pseudobutyrivibrio, Lachnospiraceae, Ruminococcaceae, Prevotellaceae, Bacteroidales, and Clostridiales. In total, 60 OTUs were found significantly (P≤0.05 correlated with feed degradability, ammonia concentration, and molar percentage of volatile fatty acids. Taken together, this study demonstrated extensive impact of EOs on rumen bacterial communities in an EO type-dependent manner, especially those in the predominant families Prevotellaceae, Lachnospiraceae and Ruminococcaceae. The information from this study may aid in understanding the effect of EOs on feed digestion and fermentation by rumen bacteria.

  18. Pepsin homologues in bacteria

    Directory of Open Access Journals (Sweden)

    Bateman Alex

    2009-09-01

    Full Text Available Abstract Background Peptidase family A1, to which pepsin belongs, had been assumed to be restricted to eukaryotes. The tertiary structure of pepsin shows two lobes with similar folds and it has been suggested that the gene has arisen from an ancient duplication and fusion event. The only sequence similarity between the lobes is restricted to the motif around the active site aspartate and a hydrophobic-hydrophobic-Gly motif. Together, these contribute to an essential structural feature known as a psi-loop. There is one such psi-loop in each lobe, and so each lobe presents an active Asp. The human immunodeficiency virus peptidase, retropepsin, from peptidase family A2 also has a similar fold but consists of one lobe only and has to dimerize to be active. All known members of family A1 show the bilobed structure, but it is unclear if the ancestor of family A1 was similar to an A2 peptidase, or if the ancestral retropepsin was derived from a half-pepsin gene. The presence of a pepsin homologue in a prokaryote might give insights into the evolution of the pepsin family. Results Homologues of the aspartic peptidase pepsin have been found in the completed genomic sequences from seven species of bacteria. The bacterial homologues, unlike those from eukaryotes, do not possess signal peptides, and would therefore be intracellular acting at neutral pH. The bacterial homologues have Thr218 replaced by Asp, a change which in renin has been shown to confer activity at neutral pH. No pepsin homologues could be detected in any archaean genome. Conclusion The peptidase family A1 is found in some species of bacteria as well as eukaryotes. The bacterial homologues fall into two groups, one from oceanic bacteria and one from plant symbionts. The bacterial homologues are all predicted to be intracellular proteins, unlike the eukaryotic enzymes. The bacterial homologues are bilobed like pepsin, implying that if no horizontal gene transfer has occurred the duplication

  19. Identification and characterization of symbiotic genes on the Rhizobium leguminosarum pre sym-plasmid

    NARCIS (Netherlands)

    Schetgens, T.M.P.

    1986-01-01

    Bacteria of the genera Rhizobium and Bradyrhizobium are unique in their quality to form nitrogen-fixing root nodules in symbiosis with leguminous plants. In fast-growing Rhizobium bacteria the genes involved in host recognition and nodule

  20. [Nod factors, chemical signal exchange between bacteria and leguminous plants in nitrogen fixing symbiosis].

    Science.gov (United States)

    Promé, J C

    1999-05-01

    The early steps of the nitrogen-fixing symbiosis between plant legumes and soil bacteria (rhizobium) are mediated by an exchange of chemical signals between the two partners. Upon gene activation by plant root secretions (flavonoids), bacteria synthesize lipochitooligomers (called Nod Factors, NFs) that induce root hair deformations, cortical cell divisions, allow bacterial entry and produce nodule organogenesis at nano to picomole concentrations. Substitutions occurring on the lipochitooligosaccharide core are essential for recognition and activity. Biosynthesis of these molecules is now fully dissected, by looking at the structural changes in NFs induced by gene mutation or gene transfers. From the biodiversity studies of NFs, it appears that their structures belong with the phylogenetic evolution of plants, rather than that of bacteria, suggesting a coevolution of symbiotic bacteria with their plant receptors. Some preliminary and indirect observations indicate that similar molecules seem to exist in non-legumes plants, in batrachians and fishes beeing possibly involved in their embryogenesis, but they are probably at at a so low concentration that all attempts to detect them directly fail up to now.

  1. Reprogrammable microbial cell-based therapeutics against antibiotic-resistant bacteria.

    Science.gov (United States)

    Hwang, In Young; Koh, Elvin; Kim, Hye Rim; Yew, Wen Shan; Chang, Matthew Wook

    2016-07-01

    The discovery of antimicrobial drugs and their subsequent use has offered an effective treatment option for bacterial infections, reducing morbidity and mortality over the past 60 years. However, the indiscriminate use of antimicrobials in the clinical, community and agricultural settings has resulted in selection for multidrug-resistant bacteria, which has led to the prediction of possible re-entrance to the pre-antibiotic era. The situation is further exacerbated by significantly reduced antimicrobial drug discovery efforts by large pharmaceutical companies, resulting in a steady decline in the number of new antimicrobial agents brought to the market in the past several decades. Consequently, there is a pressing need for new antimicrobial therapies that can be readily designed and implemented. Recently, it has become clear that the administration of broad-spectrum antibiotics can lead to collateral damage to the human commensal microbiota, which plays several key roles in host health. Advances in genetic engineering have opened the possibility of reprogramming commensal bacteria that are in symbiotic existence throughout the human body to implement antimicrobial drugs with high versatility and efficacy against pathogenic bacteria. In this review, we discuss recent advances and potentialities of engineered bacteria in providing a novel antimicrobial strategy against antibiotic resistance. Copyright © 2016 Elsevier Ltd. All rights reserved.

  2. Population Dynamic of Dendronephthya sp.-Associated Bacteria in Natural and Artificial Habitats

    Directory of Open Access Journals (Sweden)

    SUSAN SOKA

    2011-06-01

    Full Text Available Dendronephthya sp. is a soft coral that has huge distribution starting from Indopacific, Tonga, Solomon Islands to Great Barrier Reef in Australia. However, this soft corals survive only in short period after cultivation in artificial habitat (aquarium. Recent study showed that the soft coral Dendronephtya sp. has an association or symbiotic relationship with several bacteria, commonly known as coral associated bacteria (CAB. In this study, we compared the population dynamic of Dendronephthya sp.-associated bacteria in natural and artificial habitat, resulting different bacterial community profiles using terminal restriction fragment length polymorphism (T-RFLP analysis of bacterial community DNA. There were 15 main classes of bacterial population identified along with uncultured microorganism, uncultured organism, uncultured bacteria and unidentified organism. Members of Actinobacteria, Arthrobacteria, Chlorobia, Caldilineae, Δ-proteobacteria and Proteobacteria were predicted to give contributions in the survival ability of both Dendronephthya sp. The cultivation of soft corals after 2 weeks in artificial habitat increases bacterial population similarity on 2 different samples by 10%. Bacterial population similarity in artificial habitat would increase along with the longer cultivation time of soft corals.

  3. Population Dynamic of Dendronephthya sp.-Associated Bacteria in Natural and Artificial Habitats

    Directory of Open Access Journals (Sweden)

    SUSAN SOKA

    2011-06-01

    Full Text Available Dendronephthya sp. is a soft coral that has huge distribution starting from Indopacific, Tonga, Solomon Islands to Great Barrier Reef in Australia. However, this soft corals survive only in short period after cultivation in artificial habitat (aquarium. Recent study showed that the soft coral Dendronephtya sp. has an association or symbiotic relationship with several bacteria, commonly known as coral associated bacteria (CAB. In this study, we compared the population dynamic of Dendronephthya sp.-associated bacteria in natural and artificial habitat, resulting different bacterial community profiles using terminal restriction fragment length polymorphism (T-RFLP analysis of bacterial community DNA. There were 15 main classes of bacterial population identified along with uncultured microorganism, uncultured organism, uncultured bacteria and unidentified organism. Members of Actinobacteria, Arthrobacteria, Chlorobia, Caldilineae, -proteobacteria and Proteobacteria were predicted to give contributions in the survival ability of both Dendronephthya sp. The cultivation of soft corals after 2 weeks in artificial habitat increases bacterial population similarity on 2 different samples by 10%. Bacterial population similarity in artificial habitat would increase along with the longer cultivation time of soft corals.

  4. Bacteria counting method based on polyaniline/bacteria thin film.

    Science.gov (United States)

    Zhihua, Li; Xuetao, Hu; Jiyong, Shi; Xiaobo, Zou; Xiaowei, Huang; Xucheng, Zhou; Tahir, Haroon Elrasheid; Holmes, Mel; Povey, Malcolm

    2016-07-15

    A simple and rapid bacteria counting method based on polyaniline (PANI)/bacteria thin film was proposed. Since the negative effects of immobilized bacteria on the deposition of PANI on glass carbon electrode (GCE), PANI/bacteria thin films containing decreased amount of PANI would be obtained when increasing the bacteria concentration. The prepared PANI/bacteria film was characterized with cyclic voltammetry (CV) technique to provide quantitative index for the determination of the bacteria count, and electrochemical impedance spectroscopy (EIS) was also performed to further investigate the difference in the PANI/bacteria films. Good linear relationship of the peak currents of the CVs and the log total count of bacteria (Bacillus subtilis) could be established using the equation Y=-30.413X+272.560 (R(2)=0.982) over the range of 5.3×10(4) to 5.3×10(8)CFUmL(-1), which also showed acceptable stability, reproducibility and switchable ability. The proposed method was feasible for simple and rapid counting of bacteria. Copyright © 2016 Elsevier B.V. All rights reserved.

  5. Symbiotic lifestyle expression by fungal endophytes and the adaptation of plants to stress: unraveling the complexities of intimacy

    Science.gov (United States)

    Redman, Regina S.; Henson, Joan M.; Rodriguez, Russell J.

    2005-01-01

    The fossil record indicates that fungal symbionts have been associated with plants since the Ordovician period (approximately 400 million years ago), when plants first became established on land (Pirozynski and Malloch, 1975; Redecker et al., 2000; Remy et al., 1994; Simon et al., 1993). Transitioning from aquatic to terrestrial habitats likely presented plants with new stresses, including periods of desiccation. Since symbiotic fungi are known to confer drought tolerance to plants (Bacon, 1993; Read and Camp, 1986), it has been suggested that fungal symbiosis was involved with or responsible for the establishment of land plants (Pirozynski and Malloch, 1975). Symbiosis was first defined by De Bary in 1879, and since that time, all plants in natural ecosystems have been found to be colonized with fungal and bacterial symbionts. It is clear that individual plants represent symbiotic communities with microorganisms associated in or on tissues below- and aboveground.There are two major classes of fungal symbionts associated with internal plant tissues: fungal endophytes that reside entirely within plants and may be associated with roots, stems leaves, or flowers; and mycorrhizal fungi that reside only in roots but extend out into the rhizosphere. In addition, fungal endophytes may be divided into two classes: (1) a relatively small number of fastidious species that are limited to a few monocot hosts (Clay and Schardl, 2002), and (2) a large number of tractable species with broad host ranges, including both monocots and eudicots (Stone et al., 2000). While significant resources and research have been invested in mycorrhizae and class 1 endophytes, comparatively little is known about class 2 endophytes, which may represent the largest group of fungal symbionts. This is partially because the symbiotic functionalities of class 2 endophytes have only recently been elucidated and shown to be responsible for the adaptation of some plants to high-stress environments (Redman

  6. Chemical communication in bacteria

    Science.gov (United States)

    Suravajhala, Srinivasa Sandeep; Saini, Deepak; Nott, Prabhu

    Luminescence in Vibrio fischeri is a model for quorum-sensing-gene-regulation in bacteria. We study luminescence response of V. fischeri to both internal and external cues at the single cell and population level. Experiments with ES114, a wild-type strain, and ainS mutant show that luminescence induction in cultures is not always proportional to cell-density and there is always a basal level of luminescence. At any given concentration of the exogenously added signals, C6-HSL and C8-HSL, luminescence per cell reaches a maximum during the exponential phase and decreases thereafter. We hypothesize that (1) C6-HSL production and LuxR activity are not proportional to cell-density, and (2) there is a shift in equilibrium from C6-HSL to C8-HSL during the later stages of growth of the culture. RT-PCR analysis of luxI and luxR shows that the expression of these genes is maximum corresponding to the highest level of luminescence. The shift in equilibrium is shown by studying competitive binding of C6-HSL and C8-HSL to LuxR. We argue that luminescence is a unicellular behaviour, and an intensive property like per cell luminescence is more important than gross luminescence of the population in understanding response of bacteria to chemical signalling. Funding from the Department of Science and Technology, India is acknowledged.

  7. Different temperatures select distinctive acetic acid bacteria species and promotes organic acids production during Kombucha tea fermentation.

    Science.gov (United States)

    De Filippis, Francesca; Troise, Antonio Dario; Vitaglione, Paola; Ercolini, Danilo

    2018-08-01

    Kombucha is a traditional beverage produced by tea fermentation, carried out by a symbiotic consortium of bacteria and yeasts. Acetic Acid Bacteria (AAB) usually dominate the bacterial community of Kombucha, driving the fermentative process. The consumption of this beverage was often associated to beneficial effects for the health, due to its antioxidant and detoxifying properties. We characterized bacterial populations of Kombucha tea fermented at 20 or 30 °C by using culture-dependent and -independent methods and monitored the concentration of gluconic and glucuronic acids, as well as of total polyphenols. We found significant differences in the microbiota at the two temperatures. Moreover, different species of Gluconacetobacter were selected, leading to a differential abundance of gluconic and glucuronic acids. Copyright © 2018 Elsevier Ltd. All rights reserved.

  8. A Biosensor-Based Leaf Punch Assay for Glutamine Correlates to Symbiotic Nitrogen Fixation Measurements in Legumes to Permit Rapid Screening of Rhizobia Inoculants under Controlled Conditions.

    Science.gov (United States)

    Thilakarathna, Malinda S; Moroz, Nicholas; Raizada, Manish N

    2017-01-01

    Legumes are protein sources for billions of humans and livestock. These traits are enabled by symbiotic nitrogen fixation (SNF), whereby root nodule-inhabiting rhizobia bacteria convert atmospheric nitrogen (N) into usable N. Unfortunately, SNF rates in legume crops suffer from undiagnosed incompatible/suboptimal interactions between crop varieties and rhizobia strains. There are opportunities to test much large numbers of rhizobia strains if cost/labor-effective diagnostic tests become available which may especially benefit researchers in developing countries. Inside root nodules, fixed N from rhizobia is assimilated into amino acids including glutamine (Gln) for export to shoots as the major fraction (amide-exporting legumes) or as the minor fraction (ureide-exporting legumes). Here, we have developed a new leaf punch based technique to screen rhizobia inoculants for SNF activity following inoculation of both amide exporting and ureide exporting legumes. The assay is based on measuring Gln output using the GlnLux biosensor, which consists of Escherichia coli cells auxotrophic for Gln and expressing a constitutive lux operon. Subsistence farmer varieties of an amide exporter (lentil) and two ureide exporters (cowpea and soybean) were inoculated with different strains of rhizobia under controlled conditions, then extracts of single leaf punches were incubated with GlnLux cells, and light-output was measured using a 96-well luminometer. In the absence of external N and under controlled conditions, the results from the leaf punch assay correlated with 15 N-based measurements, shoot N percentage, and shoot total fixed N in all three crops. The technology is rapid, inexpensive, high-throughput, requires minimum technical expertise and very little tissue, and hence is relatively non-destructive. We compared and contrasted the benefits and limitations of this novel diagnostic assay to methods.

  9. A Biosensor-Based Leaf Punch Assay for Glutamine Correlates to Symbiotic Nitrogen Fixation Measurements in Legumes to Permit Rapid Screening of Rhizobia Inoculants under Controlled Conditions

    Directory of Open Access Journals (Sweden)

    Malinda S. Thilakarathna

    2017-10-01

    Full Text Available Legumes are protein sources for billions of humans and livestock. These traits are enabled by symbiotic nitrogen fixation (SNF, whereby root nodule-inhabiting rhizobia bacteria convert atmospheric nitrogen (N into usable N. Unfortunately, SNF rates in legume crops suffer from undiagnosed incompatible/suboptimal interactions between crop varieties and rhizobia strains. There are opportunities to test much large numbers of rhizobia strains if cost/labor-effective diagnostic tests become available which may especially benefit researchers in developing countries. Inside root nodules, fixed N from rhizobia is assimilated into amino acids including glutamine (Gln for export to shoots as the major fraction (amide-exporting legumes or as the minor fraction (ureide-exporting legumes. Here, we have developed a new leaf punch based technique to screen rhizobia inoculants for SNF activity following inoculation of both amide exporting and ureide exporting legumes. The assay is based on measuring Gln output using the GlnLux biosensor, which consists of Escherichia coli cells auxotrophic for Gln and expressing a constitutive lux operon. Subsistence farmer varieties of an amide exporter (lentil and two ureide exporters (cowpea and soybean were inoculated with different strains of rhizobia under controlled conditions, then extracts of single leaf punches were incubated with GlnLux cells, and light-output was measured using a 96-well luminometer. In the absence of external N and under controlled conditions, the results from the leaf punch assay correlated with 15N-based measurements, shoot N percentage, and shoot total fixed N in all three crops. The technology is rapid, inexpensive, high-throughput, requires minimum technical expertise and very little tissue, and hence is relatively non-destructive. We compared and contrasted the benefits and limitations of this novel diagnostic assay to methods.

  10. NAD(P)+-malic enzyme mutants of Sinorhizobium sp. strain NGR234, but not Azorhizobium caulinodans ORS571, maintain symbiotic N2 fixation capabilities.

    Science.gov (United States)

    Zhang, Ye; Aono, Toshihiro; Poole, Phillip; Finan, Turlough M

    2012-04-01

    C(4)-dicarboxylic acids appear to be metabolized via the tricarboxylic acid (TCA) cycle in N(2)-fixing bacteria (bacteroids) within legume nodules. In Sinorhizobium meliloti bacteroids from alfalfa, NAD(+)-malic enzyme (DME) is required for N(2) fixation, and this activity is thought to be required for the anaplerotic synthesis of pyruvate. In contrast, in the pea symbiont Rhizobium leguminosarum, pyruvate synthesis occurs via either DME or a pathway catalyzed by phosphoenolpyruvate carboxykinase (PCK) and pyruvate kinase (PYK). Here we report that dme mutants of the broad-host-range Sinorhizobium sp. strain NGR234 formed nodules whose level of N(2) fixation varied from 27 to 83% (plant dry weight) of the wild-type level, depending on the host plant inoculated. NGR234 bacteroids had significant PCK activity, and while single pckA and single dme mutants fixed N(2) at reduced rates, a pckA dme double mutant had no N(2)-fixing activity (Fix(-)). Thus, NGR234 bacteroids appear to synthesize pyruvate from TCA cycle intermediates via DME or PCK pathways. These NGR234 data, together with other reports, suggested that the completely Fix(-) phenotype of S. meliloti dme mutants may be specific to the alfalfa-S. meliloti symbiosis. We therefore examined the ME-like genes azc3656 and azc0119 from Azorhizobium caulinodans, as azc3656 mutants were previously shown to form Fix(-) nodules on the tropical legume Sesbania rostrata. We found that purified AZC3656 protein is an NAD(P)(+)-malic enzyme whose activity is inhibited by acetyl-coenzyme A (acetyl-CoA) and stimulated by succinate and fumarate. Thus, whereas DME is required for symbiotic N(2) fixation in A. caulinodans and S. meliloti, in other rhizobia this activity can be bypassed via another pathway(s).

  11. Assimilation (in vitro) of cholesterol by yogurt bacteria.

    Science.gov (United States)

    Dilmi-Bouras, Abdelkader

    2006-01-01

    A considerable variation is noticed between the different species studied and even between the strains of the same species, in the assimilation of cholesterol in synthetic media, in presence of different concentrations of bile salts and under anaerobiosis conditions. The obtained results show that certain strains of Streptococcus thermophilus and Lactobacillus bulgaricus resist bile salts and assimilate appreciable cholesterol quantities in their presence. The study of associations shows that only strains assimilating cholesterol in a pure state remain active when they are put in associations, but there is no additional effect. However, the symbiotic effect between Streptococcus thermophilus and Lactobacillus bulgaricus of yogurt, with regard to bile salts, is confirmed. The lactic fermenters of yogurt (Y2) reduce the levels of total cholesterol, HDL-cholesterol and LDL-cholesterol, in a well-balanced way. In all cases, the assimilated quantity of HDL-cholesterol is lower than that of LDL-cholesterol. Moreover, yogurt Y2 keeps a significant number of bacteria, superior to 10(8) cells ml(-1), and has a good taste 10 days after its production.

  12. Indigenous opportunistic bacteria inhabit mammalian gut-associated lymphoid tissues and share a mucosal antibody-mediated symbiosis.

    Science.gov (United States)

    Obata, Takashi; Goto, Yoshiyuki; Kunisawa, Jun; Sato, Shintaro; Sakamoto, Mitsuo; Setoyama, Hiromi; Matsuki, Takahiro; Nonaka, Kazuhiko; Shibata, Naoko; Gohda, Masashi; Kagiyama, Yuki; Nochi, Tomonori; Yuki, Yoshikazu; Fukuyama, Yoshiko; Mukai, Akira; Shinzaki, Shinichiro; Fujihashi, Kohtaro; Sasakawa, Chihiro; Iijima, Hideki; Goto, Masatoshi; Umesaki, Yoshinori; Benno, Yoshimi; Kiyono, Hiroshi

    2010-04-20

    The indigenous bacteria create natural cohabitation niches together with mucosal Abs in the gastrointestinal (GI) tract. Here we report that opportunistic bacteria, largely Alcaligenes species, specifically inhabit host Peyer's patches (PPs) and isolated lymphoid follicles, with the associated preferential induction of antigen-specific mucosal IgA Abs in the GI tract. Alcaligenes were identified as the dominant bacteria on the interior of PPs from naïve, specific-pathogen-free but not from germ-free mice. Oral transfer of intratissue uncultured Alcaligenes into germ-free mice resulted in the presence of Alcaligenes inside the PPs of recipients. This result was further supported by the induction of antigen-specific Ab-producing cells in the mucosal (e.g., PPs) but not systemic compartment (e.g., spleen). The preferential presence of Alcaligenes inside PPs and the associated induction of intestinal secretory IgA Abs were also observed in both monkeys and humans. Localized mucosal Ab-mediated symbiotic immune responses were supported by Alcaligenes-stimulated CD11c(+) dendritic cells (DCs) producing the Ab-enhancing cytokines TGF-beta, B-cell-activating factor belonging to the TNF family, and IL-6 in PPs. These CD11c(+) DCs did not migrate beyond the draining mesenteric lymph nodes. In the absence of antigen-specific mucosal Abs, the presence of Alcaligenes in PPs was greatly diminished. Thus, indigenous opportunistic bacteria uniquely inhabit PPs, leading to PP-DCs-initiated, local antigen-specific Ab production; this may involve the creation of an optimal symbiotic environment on the interior of the PPs.

  13. Cable Bacteria in Freshwater Sediments

    DEFF Research Database (Denmark)

    Risgaard-Petersen, Nils; Kristiansen, Michael; Frederiksen, Rasmus

    2015-01-01

    In marine sediments cathodic oxygen reduction at the sediment surface can be coupled to anodic sulfide oxidation in deeper anoxic layers through electrical currents mediated by filamentous, multicellular bacteria of the Desulfobulbaceae family, the so-called cable bacteria. Until now, cable...... bacteria have only been reported from marine environments. In this study, we demonstrate that cable bacteria also occur in freshwater sediments. In a first step, homogenized sediment collected from the freshwater stream Giber Å, Denmark, was incubated in the laboratory. After 2 weeks, pH signatures...... marine cable bacteria, with the genus Desulfobulbus as the closest cultured lineage. The results of the present study indicate that electric currents mediated by cable bacteria could be important for the biogeochemistry in many more environments than anticipated thus far and suggest a common evolutionary...

  14. Immunomodulatory properties of probiotic bacteria

    DEFF Research Database (Denmark)

    Fink, Lisbeth Nielsen

    2007-01-01

    Certain lactic acid bacteria (LAB) are part of the commensal intestinal flora and considered beneficial for health, as they compete with pathogens for adhesion sites in the intestine and ferment otherwise indigestible compounds. Another important property of these so-called probiotic bacteria...... with bacteria, and the cytokine pattern induced by specific bacteria resembled the pattern induced in MoDC, except for TNF-alpha and IL-6, which were induced in response to different bacteria in blood DC/monocytes and monocyte-derived DC. Autologous NK cells produced IFN-gamma when cultured with blood DC......, monocytes and monocyte-derived DC and IL-12-inducing bacteria, whereas only DC induced IFN-gamma production in allogeneic T cells. In vitro-generated DC is a commonly used model of tissue DC, but they differ in certain aspects from intestinal DC, which are in direct contact with the intestinal microbiota...

  15. Phenotypic switching in bacteria

    Science.gov (United States)

    Merrin, Jack

    Living matter is a non-equilibrium system in which many components work in parallel to perpetuate themselves through a fluctuating environment. Physiological states or functionalities revealed by a particular environment are called phenotypes. Transitions between phenotypes may occur either spontaneously or via interaction with the environment. Even in the same environment, genetically identical bacteria can exhibit different phenotypes of a continuous or discrete nature. In this thesis, we pursued three lines of investigation into discrete phenotypic heterogeneity in bacterial populations: the quantitative characterization of the so-called bacterial persistence, a theoretical model of phenotypic switching based on those measurements, and the design of artificial genetic networks which implement this model. Persistence is the phenotype of a subpopulation of bacteria with a reduced sensitivity to antibiotics. We developed a microfluidic apparatus, which allowed us to monitor the growth rates of individual cells while applying repeated cycles of antibiotic treatments. We were able to identify distinct phenotypes (normal and persistent) and characterize the stochastic transitions between them. We also found that phenotypic heterogeneity was present prior to any environmental cue such as antibiotic exposure. Motivated by the experiments with persisters, we formulated a theoretical model describing the dynamic behavior of several discrete phenotypes in a periodically varying environment. This theoretical framework allowed us to quantitatively predict the fitness of dynamic populations and to compare survival strategies according to environmental time-symmetries. These calculations suggested that persistence is a strategy used by bacterial populations to adapt to fluctuating environments. Knowledge of the phenotypic transition rates for persistence may provide statistical information about the typical environments of bacteria. We also describe a design of artificial

  16. Polishing of Anaerobic Secondary Effluent and Symbiotic Bioremediation of Raw Municipal Wastewater by Chlorella Vulgaris

    KAUST Repository

    Cheng, Tuoyuan

    2016-05-01

    To assess polishing of anaerobic secondary effluent and symbiotic bioremediation of primary effluent by microalgae, bench scale bubbling column reactors were operated in batch modes to test nutrients removal capacity and associated factors. Chemical oxygen demand (COD) together with oil and grease in terms of hexane extractable material (HEM) in the reactors were measured after batch cultivation tests of Chlorella Vulgaris, indicating the releasing algal metabolites were oleaginous (dissolved HEM up to 8.470 mg/L) and might hazard effluent quality. Ultrafiltration adopted as solid-liquid separation step was studied via critical flux and liquid chromatography-organic carbon detection (LC-OCD) analysis. Although nutrients removal was dominated by algal assimilation, nitrogen removal (99.6% maximum) was affected by generation time (2.49 days minimum) instead of specific nitrogen removal rate (sN, 20.72% maximum), while phosphorus removal (49.83% maximum) was related to both generation time and specific phosphorus removal rate (sP, 1.50% maximum). COD increase was affected by cell concentration (370.90 mg/L maximum), specific COD change rate (sCOD, 0.87 maximum) and shading effect. sCOD results implied algal metabolic pathway shift under nutrients stress, generally from lipid accumulation to starch accumulation when phosphorus lower than 5 mg/L, while HEM for batches with initial nitrogen of 10 mg/L implied this threshold around 8 mg/L. HEM and COD results implied algal metabolic pathway shift under nutrients stress. Anaerobic membrane bioreactor effluent polishing showed similar results to synthetic anaerobic secondary effluent with slight inhibition while 4 symbiotic bioremediation of raw municipal wastewater with microalgae and activated sludge showed competition for ammonium together with precipitation or microalgal luxury uptake of phosphorus. Critical flux was governed by algal cell concentration for ultrafiltration membrane with pore size of 30 nm, while

  17. Low variation in ribosomal DNA and internal transcribed spacers of the symbiotic fungi of leaf-cutting ants (Attini: Formicidae

    Directory of Open Access Journals (Sweden)

    Silva-Pinhati A.C.O.

    2004-01-01

    Full Text Available Leaf-cutting ants of the genera Atta and Acromyrmex (tribe Attini are symbiotic with basidiomycete fungi of the genus Leucoagaricus (tribe Leucocoprineae, which they cultivate on vegetable matter inside their nests. We determined the variation of the 28S, 18S, and 5.8S ribosomal DNA (rDNA gene loci and the rapidly evolving internal transcribed spacers 1 and 2 (ITS1 and ITS2 of 15 sympatric and allopatric fungi associated with colonies of 11 species of leafcutter ants living up to 2,600 km apart in Brazil. We found that the fungal rDNA and ITS sequences from different species of ants were identical (or nearly identical to each other, whereas 10 GenBank Leucoagaricus species showed higher ITS variation. Our findings suggest that Atta and Acromyrmex leafcutters living in geographic sites that are very distant from each other cultivate a single fungal species made up of closely related lineages of Leucoagaricus gongylophorus. We discuss the strikingly high similarity in the ITS1 and ITS2 regions of the Atta and Acromyrmex symbiotic L. gongylophorus studied by us, in contrast to the lower similarity displayed by their non-symbiotic counterparts. We suggest that the similarity of our L. gongylophorus isolates is an indication of the recent association of the fungus with these ants, and propose that both the intense lateral transmission of fungal material within leafcutter nests and the selection of more adapted fungal strains are involved in the homogenization of the symbiotic fungal stock.

  18. An exploration of the midwifery continuity of care program at one Australian University as a symbiotic clinical education model.

    Science.gov (United States)

    Sweet, Linda P; Glover, Pauline

    2013-03-01

    This discussion paper analyses a midwifery Continuity of Care program at an Australian University with the symbiotic clinical education model, to identify strengths and weakness, and identify ways in which this new pedagogical approach can be improved. In 2002 a major change in Australian midwifery curricula was the introduction of a pedagogical innovation known as the Continuity of Care experience. This innovation contributes a significant portion of clinical experience for midwifery students. It is intended as a way to give midwifery students the opportunity to provide continuity of care in partnership with women, through their pregnancy and childbirth, thus imitating a model of continuity of care and continuity of carer. A qualitative study was conducted in 2008/9 as part of an Australian Learning and Teaching Council Associate Fellowship. Evidence and findings from this project (reported elsewhere) are used in this paper to illustrate the evaluation of midwifery Continuity of Care experience program at an Australian university with the symbiotic clinical education model. Strengths of the current Continuity of Care experience are the strong focus on relationships between midwifery students and women, and early clinical exposure to professional practice. Improved facilitation through the development of stronger relationships with clinicians will improve learning, and result in improved access to authentic supported learning and increased provision of formative feedback. This paper presents a timely review of the Continuity of Care experience for midwifery student learning and highlights the potential of applying the symbiotic clinical education model to enhance learning. Applying the symbiotic clinical education framework to evidence gathered about the Continuity of Care experience in Australian midwifery education highlights strengths and weaknesses which may be used to guide curricula and pedagogical improvements. Copyright © 2011 Elsevier Ltd. All rights

  19. The bacterium Wolbachia exploits host innate immunity to establish a symbiotic relationship with the dengue vector mosquito Aedes aegypti

    OpenAIRE

    Pan, Xiaoling; Pike, Andrew; Joshi, Deepak; Bian, Guowu; McFadden, Michael J; Lu, Peng; Liang, Xiao; Zhang, Fengrui; Raikhel, Alexander S; Xi, Zhiyong

    2017-01-01

    A host’s immune system plays a central role in shaping the composition of the microbiota and, in return, resident microbes influence immune responses. Symbiotic associations of the maternally transmitted bacterium Wolbachia occur with a wide range of arthropods. It is, however, absent from the dengue and Zika vector mosquito Aedes aegypti in nature. When Wolbachia is artificially forced to form symbiosis with this new mosquito host, it boosts the basal immune response and enhances the mosquit...

  20. Cell death and degeneration in the symbiotic\\ud dinoflagellates of the coral Stylophora pistillata\\ud during bleaching

    OpenAIRE

    Franklin, Daniel J.; Hoegh-Guldberg, O.; Jones, R.J.; Berges , John A.

    2004-01-01

    Rising sea temperatures are increasing the incidences of mass coral bleaching (the dissociation\\ud of the coral–algal symbiosis) and coral mortality. In this study, the effects of bleaching\\ud (induced by elevated light and temperature) on the condition of symbiotic dinoflagellates (Symbiodinium\\ud sp.) within the tissue of the hard coral Stylophora pistillata (Esper) were assessed using a suite\\ud of techniques. Bleaching of S. pistillata was accompanied by declines in the maximum potential\\...

  1. [Chitinolytic activity of bacteria].

    Science.gov (United States)

    Saks, Elzbieta; Jankiewicz, Urszula

    2010-01-01

    Chitinolytic bacteria play an important role in degradation of chitin, one of the most abundant biopolymers in nature. These microorganisms synthesize specific enzymes, that catalyze hydrolysis of beta-1,4-glycosidic bonds in low-digestible chitin polymers, turning it into low-molecular, easy to digest compounds. During last decades many bacterial chitinolytic enzymes have been studied and characterized, mainly for their potential applications in agriculture, industry and medicine. Several chitinase classifications have been proposed, either on the base of substrate specificity or amino acid sequence similarities. X-ray crystallography and NMR spectroscopy techniques enabled the determination of three dimensional structure of some chitinases, what was helpful in explaining their catalytic mechanism. Development of biotechnology and molecular biology enables a deep research in regulation and cloning of bacterial chitinase genes.

  2. Bacteria, phages and septicemia.

    Directory of Open Access Journals (Sweden)

    Ausra Gaidelyte

    Full Text Available The use of phages is an attractive option to battle antibiotic resistant bacteria in certain bacterial infections, but the role of phage ecology in bacterial infections is obscure. Here we surveyed the phage ecology in septicemia, the most severe type of bacterial infection. We observed that the majority of the bacterial isolates from septicemia patients spontaneously secreted phages active against other isolates of the same bacterial strain, but not to the strain causing the disease. Such phages were also detected in the initial blood cultures, indicating that phages are circulating in the blood at the onset of sepsis. The fact that most of the septicemic bacterial isolates carry functional prophages suggests an active role of phages in bacterial infections. Apparently, prophages present in sepsis-causing bacterial clones play a role in clonal selection during bacterial invasion.

  3. Acoustofluidic bacteria separation

    International Nuclear Information System (INIS)

    Li, Sixing; Huang, Tony Jun; Ma, Fen; Zeng, Xiangqun; Bachman, Hunter; Cameron, Craig E

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device. (paper)

  4. Acoustofluidic bacteria separation

    Science.gov (United States)

    Li, Sixing; Ma, Fen; Bachman, Hunter; Cameron, Craig E.; Zeng, Xiangqun; Huang, Tony Jun

    2017-01-01

    Bacterial separation from human blood samples can help with the identification of pathogenic bacteria for sepsis diagnosis. In this work, we report an acoustofluidic device for label-free bacterial separation from human blood samples. In particular, we exploit the acoustic radiation force generated from a tilted-angle standing surface acoustic wave (taSSAW) field to separate Escherichia coli from human blood cells based on their size difference. Flow cytometry analysis of the E. coli separated from red blood cells shows a purity of more than 96%. Moreover, the label-free electrochemical detection of the separated E. coli displays reduced non-specific signals due to the removal of blood cells. Our acoustofluidic bacterial separation platform has advantages such as label-free separation, high biocompatibility, flexibility, low cost, miniaturization, automation, and ease of in-line integration. The platform can be incorporated with an on-chip sensor to realize a point-of-care sepsis diagnostic device.

  5. The Power at the Heart of Symbiotic Stars - Interpreting a Megasecond of X-ray and UV Observations

    Science.gov (United States)

    Sokoloski, Jennifer

    The goal of the proposed research is to find the dominant source of power -- accretion or nuclear shell burning -- for a large sample of symbiotic binary stars. Symbiotic stars are interacting binary stars in which a white dwarf accretes from the wind of a red-giant companion. For many symbiotics, clarifying the fundamental source of power is necessary for the determination of almost every one of their other key characteristics, such as the rate at which is transfered between the two stars and the mass of the accreting white dwarf. In a symbiotic binary, the hot white dwarf ionizes the surrounding wind from the red giant, which then produces high excitation emission lines. At a basic level, the ionizing flux from the hot white dwarf is the product of mass transfer from the red-giant companion. In some systems, however, much of the luminosity is due to this material being burned quasi-steadily on the surface of the WD. And since nuclear burning on at the surface of a white dwarf releases approximately 50 times more energy per nucleon than accretion, shell-burning dominates the energetics when it is present. Without a grasp of whether accretion alone or shell burning drives the optical through X-ray emission, as well as the observed outflows and eruptions, it has been difficult to extract information about typical rates of mass transfer in these binaries, the origin of the shell burning, or the interpretation of many of the observables. Now, thanks to the Swift satellite, we have found a way to move forward. We recently discovered that the source of power can be gleaned from the amplitude of rapid variations in the ultraviolet (UV) brightness, which are referred to as flickering. For this project, we will therefore use Swift observations of an existing sample of 69 symbiotic stars to determine the source of power for the majority of these targets. UV flickering reveals the source of power because white-dwarf accretion disks produce UV flickering. When shell

  6. Population genomics of the symbiotic plasmids of sympatric nitrogen-fixing Rhizobium species associated with Phaseolus vulgaris.

    Science.gov (United States)

    Pérez Carrascal, Olga M; VanInsberghe, David; Juárez, Soledad; Polz, Martin F; Vinuesa, Pablo; González, Víctor

    2016-09-01

    Cultivated common beans are the primary protein source for millions of people around the world who subsist on low-input agriculture, enabled by the symbiotic N2 -fixation these legumes perform in association with rhizobia. Within a single agricultural plot, multiple Rhizobium species can nodulate bean roots, but it is unclear how genetically isolated these species remain in sympatry. To better understand this issue, we sequenced and compared the genomes of 33 strains isolated from the rhizosphere and root nodules of a particular bean variety grown in the same agricultural plot. We found that the Rhizobium species we observed coexist with low genetic recombination across their core genomes. Accessory plasmids thought to be necessary for the saprophytic lifestyle in soil show similar levels of genetic isolation, but with higher rates of recombination than the chromosomes. However, the symbiotic plasmids are extremely similar, with high rates of recombination and do not appear to have co-evolved with the chromosome or accessory plasmids. Therefore, while Rhizobium species are genetically isolated units within the microbial community, a common symbiotic plasmid allows all Rhizobium species to engage in symbiosis with the same host in a single agricultural plot. © 2016 Society for Applied Microbiology and John Wiley & Sons Ltd.

  7. Using color as a proxy for symbiont density to assess health in the facultatively symbiotic northern coral, Astrangia poculata

    Science.gov (United States)

    Seballos, R.; Burmester, E. M.; Rotjan, R. D.

    2016-02-01

    Unlike most tropical corals, the northern star coral, Astrangia poculata, can survive and thrive with and without its photosynthetic endosymbionts, Symbiodinium psygmophilum. The degree of symbiosis is dependent on symbiont cell density, but the measurement of cell density is de facto destructive. We therefore explored the use of color (RGB) as a non-destructive proxy for symbiont state, building on the methods of Dimond and Carrington (2008). RGB color values, derived from a custom image analysis tool built in Matlab, were used to determine the inferred chlorophyll density of corals throughout an 8 week period. We found that non-destructive color analysis was a good metric to describe symbiotic state. To explore this method in an experimental context, we manipulated the impact of host condition (fed vs. starved) on the likelihood of wound healing in both symbiotic and aposymbiotic states. No difference was observed between either wounding or nutrition treatments, indicating that symbiotic state is likely controlled by other factors. In tropical corals, assessing the breakdown of symbiosis is an important predictor of holobiont stress, and colorimetric methods have been used to assess the extent of bleaching. Our method instead explores the spectral quality and extent of pigmentation to infer chlorophyll densities and symbiont cell densities, thereby extending the use of nondestructive methods to explore the strength of symbiosis.

  8. Host-dependent symbiotic efficiency of Rhizobium leguminosarum bv. trifolii strains isolated from nodules of Trifolium rubens.

    Science.gov (United States)

    Marek-Kozaczuk, Monika; Wdowiak-Wróbel, Sylwia; Kalita, Michał; Chernetskyy, Mykhaylo; Deryło, Kamil; Tchórzewski, Marek; Skorupska, Anna

    2017-12-01

    Trifolium rubens L., commonly known as the red feather clover, is capable of symbiotic interactions with rhizobia. Up to now, no specific symbionts of T. rubens and their symbiotic compatibility with Trifolium spp. have been described. We characterized the genomic diversity of T. rubens symbionts by analyses of plasmid profiles and BOX-PCR. The phylogeny of T. rubens isolates was inferred based on the nucleotide sequences of 16S rRNA and two core genes (atpD, recA). The nodC phylogeny allowed classification of rhizobia nodulating T. rubens as Rhizobium leguminosarum symbiovar trifolii (Rlt). The symbiotic efficiency of the Rlt isolates was determined on four clover species: T. rubens, T. pratense, T. repens and T. resupinatum. We determined that Rlt strains formed mostly inefficient symbiosis with their native host plant T. rubens and weakly effective (sub-optimal) symbiosis with T. repens and T. pratense. The same Rlt strains were fully compatible in the symbiosis with T. resupinatum. T. rubens did not exhibit strict selectivity in regard to the symbionts and rhizobia closely related to Rhizobium grahamii, Rhizobium galegae and Agrobacterium radiobacter, which did not nodulate Trifolium spp., were found amongst T. rubens nodule isolates.

  9. Ploidy-dependent changes in the epigenome of symbiotic cells correlate with specific patterns of gene expression

    KAUST Repository

    Nagymihály, Marianna

    2017-04-13

    The formation of symbiotic nodule cells in Medicago truncatula is driven by successive endoreduplication cycles and transcriptional reprogramming in different temporal waves including the activation of more than 600 cysteine-rich NCR genes expressed only in nodules. We show here that the transcriptional waves correlate with growing ploidy levels and have investigated how the epigenome changes during endoreduplication cycles. Differential DNA methylation was found in only a small subset of symbiotic nodule-specific genes, including more than half of the NCR genes, whereas in most genes DNA methylation was unaffected by the ploidy levels and was independent of the genes\\' active or repressed state. On the other hand, expression of nodule-specific genes correlated with ploidy-dependent opening of the chromatin as well as, in a subset of tested genes, with reduced H3K27me3 levels combined with enhanced H3K9ac levels. Our results suggest that endoreduplication-dependent epigenetic changes contribute to transcriptional reprogramming in the differentiation of symbiotic cells.

  10. Symbiotic fungi that are essential for plant nutrient uptake investigated with NMP

    International Nuclear Information System (INIS)

    Pallon, J.; Wallander, H.; Hammer, E.; Arteaga Marrero, N.; Auzelyte, V.; Elfman, M.; Kristiansson, P.; Nilsson, C.; Olsson, P.A.; Wegden, M.

    2007-01-01

    The nuclear microprobe (NMP) technique using PIXE for elemental analysis and STIM on/off axis for parallel mass density normalization has proven successful to investigate possible interactions between minerals and ectomycorrhizal (EM) mycelia that form symbiotic associations with forest trees. The ability for the EM to make elements biologically available from minerals and soil were compared in field studies and in laboratory experiments, and molecular analysis (PCR-RFLP) was used to identify ectomycorrhizal species from the field samplings. EM rhizomorphs associated with apatite in laboratory systems and in mesh bags incubated in forest ecosystems contained larger amounts of Ca than similar rhizomorphs connected to acid-washed sand. EM mycelium produced in mesh bags had a capacity to mobilize P from apatite-amended sand and a high concentration of K in some rhizomorphs suggests that these fungi are good accumulators of K and may have a significant role in transporting K to trees. Spores formed by arbuscular mycorrhizal (AM) fungi in laboratory cultures were compared with spores formed in saline soils in Tunisia in Northern Africa. We found lower concentrations of P and higher concentrations of Cl in the spores collected from the field than in the spores collected from laboratory cultures. For the case of laboratory cultures, the distribution of e.g. P and K was found to be clearly correlated

  11. Effect of inulin and oligofructose on the physicochemical, microbiological and sensory characteristics of symbiotic dairy beverages

    Directory of Open Access Journals (Sweden)

    Anderson Rodrigo Fornelli

    2014-12-01

    Full Text Available The aim of this study was to verify the effect of inulin and oligofructose on the physicochemical, microbiological and sensory characteristics of symbiotic dairy beverages. Four formulations were made: 1 a control (C; 2 a sample with added Lactobacillus paracasei (P; 3 a sample with added L. paracasei and inulin (PI; and 4 a sample with added L. paracasei and oligofructose (PO. The probiotic population, pH, and acidity of the products were evaluated once a week for 21 days while refrigerated (5±1°C. Possible contaminating microorganisms (coliforms, E. coli, and Salmonella spp. were investigated after three days of storage. Sensorial acceptance and purchase intention were evaluated seven days after manufacture. Dairy beverages presented with L. paracasei populations above 8.50 log CFU/mL during the whole storage period. Significantly (p<0.05 lower pH values were observed in P and PI, and higher acidity values were found in all formulations throughout storage. The dairy beverages were considered to be a promising matrix for the probiotic microorganism L. paracasei. The prebiotic additions (inulin and oligofructose did not interfere with the overall acceptance and intention to purchase the beverages.

  12. Acquisition of symbiotic dinoflagellates ( Symbiodinium) by juveniles of the coral Acropora longicyathus

    Science.gov (United States)

    Del C. Gómez-Cabrera, M.; Ortiz, J. C.; Loh, W. K. W.; Ward, S.; Hoegh-Guldberg, O.

    2008-03-01

    Scleractinian corals may acquire Symbiodinium from their parents (vertically) or from the environment (horizontally). In the present study, adult colonies of the coral Acropora longicyathus from One Tree Island (OTI) on the southern Great Barrier Reef (Australia) acquired two distinct varieties of symbiotic dinoflagellates ( Symbiodinium) from the environment. Adult colonies had either Symbiodinium from clade C (86.7%) or clade A (5.3%), or a mixture of both clades A and C (8.0% of all colonies). In contrast, all 10-day-old juveniles were associated with Symbiodinium from clade A, while 83-day-old colonies contained clades A, C and D even though they were growing at the same location. Symbiodinium from clade A were dominant in both 10- and 83-day-old juveniles (99 and 97% of all recruits, respectively), while clade D was also found in 31% of 83-day-old juveniles. Experimental manipulation also revealed that parental association (with clade A or C), or the location within the OTI reef, did not influence which clade of symbiont was acquired by juvenile corals. The differences between the genetic identity of populations of Symbiodinium resident in juveniles and adult A. longicyathus suggest that ontogenetic changes in the symbiosis may occur during the development of scleractinian corals. Whether or not these changes are due to host selective processes or differences in the physical environment associated with juvenile versus adult colonies remains to be determined.

  13. Fixating on metals: new insights into the role of metals in nodulation and symbiotic nitrogen fixation.

    Science.gov (United States)

    González-Guerrero, Manuel; Matthiadis, Anna; Sáez, Ángela; Long, Terri A

    2014-01-01

    Symbiotic nitrogen fixation is one of the most promising and immediate alternatives to the overuse of polluting nitrogen fertilizers for improving plant nutrition. At the core of this process are a number of metalloproteins that catalyze and provide energy for the conversion of atmospheric nitrogen to ammonia, eliminate free radicals produced by this process, and create the microaerobic conditions required by these reactions. In legumes, metal cofactors are provided to endosymbiotic rhizobia within root nodule cortical cells. However, low metal bioavailability is prevalent in most soils types, resulting in widespread plant metal deficiency and decreased nitrogen fixation capabilities. As a result, renewed efforts have been undertaken to identify the mechanisms governing metal delivery from soil to the rhizobia, and to determine how metals are used in the nodule and how they are recycled once the nodule is no longer functional. This effort is being aided by improved legume molecular biology tools (genome projects, mutant collections, and transformation methods), in addition to state-of-the-art metal visualization systems.

  14. Spectroscopic confirmation of the first symbiotic star in a globular cluster

    Science.gov (United States)

    Zurek, David

    2013-10-01

    We have recently discovered an 18-minute period in the ultraviolet of a star in the globular cluster NGC 1851. In the redder optical bands, this star is red and bright, while it shows a clear UV excess relative to other stars at similar positions in the HR diagram. The system is most likely a symbiotic binary, composed of a cool evolved star and a white dwarf, with an 18 minute spin period, accreting the cool star's wind. The binary would be the first such object ever found in a globular cluster, and only the third in the Galaxy where the white dwarf spin period is measured. The only viable alternatives are that the two components are a chance superposition - something with a nontrivial chance of happening in a globular cluster core. In such a case, the 18 minute period would most likely be the spin period of a magnetic white dwarf in an intermediate polar cataclysmic variable {this would be the first confirmed magnetic CV in a globular cluster}, or the orbital period of a double-degenerate AM CVn binary. Each of these three possibilities show unique {and very different} emission line spectra in the blue wavelength range. Two orbits of HST with STIS/G430L will produce a spectrum of sufficient signal-to-noise to distinguish between these 3 scenarios. The result will be an important constraint on N-body models of globular clusters.

  15. Dual effect of Mesorhizobium loti T3SS functionality on the symbiotic process.

    Science.gov (United States)

    Sánchez, Cintia; Mercante, Virginia; Babuin, María F; Lepek, Viviana C

    2012-05-01

    Mesorhizobium loti MAFF303099 has a functional type III secretory system (T3SS) involved in the nodulation process on Lotus tenuis and Lotus japonicus. Four putative M. loti T3SS effectors (Mlr6358, Mlr6331, Mlr6361, and Mlr6316) have been previously described, and it has been demonstrated that the N-terminal regions of Mlr6361 and Mlr6358 mediate the secretion via a T3SS. Here, we demonstrate the capacity of Mlr6316 and Mlr6331 N-terminal regions to direct the secretion of a translational fusion to a reporter peptide through T3SS. By using single, double, and triple mutants, we demonstrated the positive and negative participation of some of these proteins in the determination of competitiveness on Lotus spp. Low competitiveness values correlated with low nodulation efficiency for a mutant deficient in three of the putative M. loti effectors. Our data suggest that the net effect of M. loti T3SS function on symbiotic process with Lotus results from a balance between positive and negative effects. © 2012 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved.

  16. Key role of symbiotic dinitrogen fixation in tropical forest secondary succession

    Science.gov (United States)

    Batterman, Sarah A.; Hedin, Lars O.; van Breugel, Michiel; Ransijn, Johannes; Craven, Dylan J.; Hall, Jefferson S.

    2013-10-01

    Forests contribute a significant portion of the land carbon sink, but their ability to sequester CO2 may be constrained by nitrogen, a major plant-limiting nutrient. Many tropical forests possess tree species capable of fixing atmospheric dinitrogen (N2), but it is unclear whether this functional group can supply the nitrogen needed as forests recover from disturbance or previous land use, or expand in response to rising CO2 (refs 6, 8). Here we identify a powerful feedback mechanism in which N2 fixation can overcome ecosystem-scale deficiencies in nitrogen that emerge during periods of rapid biomass accumulation in tropical forests. Over a 300-year chronosequence in Panama, N2-fixing tree species accumulated carbon up to nine times faster per individual than their non-fixing neighbours (greatest difference in youngest forests), and showed species-specific differences in the amount and timing of fixation. As a result of fast growth and high fixation, fixers provided a large fraction of the nitrogen needed to support net forest growth (50,000kg carbon per hectare) in the first 12years. A key element of ecosystem functional diversity was ensured by the presence of different N2-fixing tree species across the entire forest age sequence. These findings show that symbiotic N2 fixation can have a central role in nitrogen cycling during tropical forest stand development, with potentially important implications for the ability of tropical forests to sequester CO2.

  17. A novel symbiotic organisms search algorithm for optimal power flow of power system with FACTS devices

    Directory of Open Access Journals (Sweden)

    Dharmbir Prasad

    2016-03-01

    Full Text Available In this paper, symbiotic organisms search (SOS algorithm is proposed for the solution of optimal power flow (OPF problem of power system equipped with flexible ac transmission systems (FACTS devices. Inspired by interaction between organisms in ecosystem, SOS algorithm is a recent population based algorithm which does not require any algorithm specific control parameters unlike other algorithms. The performance of the proposed SOS algorithm is tested on the modified IEEE-30 bus and IEEE-57 bus test systems incorporating two types of FACTS devices, namely, thyristor controlled series capacitor and thyristor controlled phase shifter at fixed locations. The OPF problem of the present work is formulated with four different objective functions viz. (a fuel cost minimization, (b transmission active power loss minimization, (c emission reduction and (d minimization of combined economic and environmental cost. The simulation results exhibit the potential of the proposed SOS algorithm and demonstrate its effectiveness for solving the OPF problem of power system incorporating FACTS devices over the other evolutionary optimization techniques that surfaced in the recent state-of-the-art literature.

  18. Discovery of radio emission from the symbiotic X-ray binary system GX 1+4

    Science.gov (United States)

    van den Eijnden, J.; Degenaar, N.; Russell, T. D.; Miller-Jones, J. C. A.; Wijnands, R.; Miller, J. M.; King, A. L.; Rupen, M. P.

    2018-02-01

    We report the discovery of radio emission from the accreting X-ray pulsar and symbiotic X-ray binary GX 1+4 with the Karl G. Jansky Very Large Array. This is the first radio detection of such a system, wherein a strongly magnetized neutron star accretes from the stellar wind of an M-type giant companion. We measure a 9 GHz radio flux density of 105.3 ± 7.3 μJy, but cannot place meaningful constraints on the spectral index due to a limited frequency range. We consider several emission mechanisms that could be responsible for the observed radio source. We conclude that the observed properties are consistent with shocks in the interaction of the accretion flow with the magnetosphere, a synchrotron-emitting jet, or a propeller-driven outflow. The stellar wind from the companion is unlikely to be the origin of the radio emission. If the detected radio emission originates from a jet, it would show that strong magnetic fields (≥1012 G) do not necessarily suppress jet formation.

  19. Unusual symbiotic cyanobacteria association in the genetically diverse intertidal marine sponge Hymeniacidon perlevis (Demospongiae, Halichondrida).

    Science.gov (United States)

    Alex, Anoop; Vasconcelos, Vitor; Tamagnini, Paula; Santos, Arlete; Antunes, Agostinho

    2012-01-01

    Cyanobacteria represent one of the most common members of the sponge-associated bacterial community and are abundant symbionts of coral reef ecosystems. In this study we used Transmission Electron Microscopy (TEM) and molecular techniques (16S rRNA gene marker) to characterize the spatial distribution of cyanobionts in the widely dispersed marine intertidal sponge Hymeniacidon perlevis along the coast of Portugal (Atlantic Ocean). We described new sponge associated cyanobacterial morphotypes (Xenococcus-like) and we further observed Acaryochloris sp. as a sponge symbiont, previously only reported in association with ascidians. Besides these two unique cyanobacteria, H. perlevis predominantly harbored Synechococcus sp. and uncultured marine cyanobacteria. Our study supports the hypothesis that the community of sponge cyanobionts varies irrespective of the geographical location and is likely influenced by seasonal fluctuations. The observed multiple cyanobacterial association among sponges of the same host species over a large distance may be attributed to horizontal transfer of symbionts. This may explain the absence of a co-evolutionary pattern between the sponge host and its symbionts. Finally, in spite of the short geographic sampling distance covered, we observed an unexpected high intra-specific genetic diversity in H. perlevis using the mitochondrial genes ATP6 (π = 0.00177), COI (π = 0.00241) and intergenic spacer SP1 (π = 0.00277) relative to the levels of genetic variation of marine sponges elsewhere. Our study suggests that genotypic variation among the sponge host H. perlevis and the associated symbiotic cyanobacteria diversity may be larger than previously recognized.

  20. Double genetically modified symbiotic system for improved Cu phytostabilization in legume roots.

    Science.gov (United States)

    Pérez-Palacios, Patricia; Romero-Aguilar, Asunción; Delgadillo, Julián; Doukkali, Bouchra; Caviedes, Miguel A; Rodríguez-Llorente, Ignacio D; Pajuelo, Eloísa

    2017-06-01

    Excess copper (Cu) in soils has deleterious effects on plant growth and can pose a risk to human health. In the last decade, legume-rhizobium symbioses became attractive biotechnological tools for metal phytostabilization. For this technique being useful, metal-tolerant symbionts are required, which can be generated through genetic manipulation.In this work, a double symbiotic system was engineered for Cu phytostabilization: On the one hand, composite Medicago truncatula plants expressing the metallothionein gene mt4a from Arabidopsis thaliana in roots were obtained to improve plant Cu tolerance. On the other hand, a genetically modified Ensifer medicae strain, expressing copper resistance genes copAB from Pseudomonas fluorescens driven by a nodulation promoter, nifHp, was used for plant inoculation. Our results indicated that expression of mt4a in composite plants ameliorated plant growth and nodulation and enhanced Cu tolerance. Lower levels of ROS-scavenging enzymes and of thiobarbituric acid reactive substances (TBARS), such as malondialdehyde (a marker of lipid peroxidation), suggested reduced oxidative stress. Furthermore, inoculation with the genetically modified Ensifer further improved root Cu accumulation without altering metal loading to shoots, leading to diminished values of metal translocation from roots to shoots. The double modified partnership is proposed as a suitable tool for Cu rhizo-phytostabilization.

  1. Nitrogen symbiotically fixed by cowpea and gliricidia in traditional and agroforestry systems under semiarid conditions

    Directory of Open Access Journals (Sweden)

    Júlio César Rodrigues Martins

    2015-02-01

    Full Text Available The objective of this work was to estimate the amounts of N fixed by cowpea in a traditional system and by cowpea and gliricidia in an agroforestry system in the Brazilian Northeast semiarid. The experiment was carried out in a randomized complete block design, in a split-plot arrangement, with four replicates, in the semiarid region of the state of Paraíba, Brazil. Plots consisted of agroforestry and traditional systems (no trees, and split-plots of the three crops planted between the tree rows in the agroforestry system. To estimate N fixation, plant samples were collected in the fourth growth cycle of the perennial species and in the fourth planting cycle of the annual species. In the agroforestry system with buffel grass and prickly-pear cactus, gliricidia plants symbiotically fix high proportions of N (>50% and contribute with higher N amounts (40 kg ha-1 in leaves than in the traditional system (11 kg ha-1 in grain and 18 kg ha-1 in straw. In the agroforestry system with maize and cowpea, gliricidia plants do not fix nitrogen, and N input is limited to the fixation by cowpea (2.7 kg ha-1, which is lower than in the traditional system due to its lower biomass production.

  2. Genetic diversity and symbiotic compatibility among rhizobial strains and Desmodium incanum and Lotus spp. plants

    Directory of Open Access Journals (Sweden)

    Camille E Granada

    2014-06-01

    Full Text Available This work aimed to evaluate the symbiotic compatibility and nodulation efficiency of rhizobia isolated from Desmodium incanum, Lotus corniculatus, L. subbiflorus, L. uliginosus and L. glaber plants by cross-inoculation. Twelve reference strains and 21 native isolates of rhizobia were genetically analyzed by the BOX-PCR technique, which showed a high genetic diversity among the rhizobia studied. The isolates were also characterized based on their production of indolic compounds and siderophores, as well as on their tolerance to salinity. Fifteen of the 33 rhizobia analyzed were able to produce indolic compounds, whereas 13 produced siderophores. All the tested rhizobia were sensitive to high salinity, although some were able to grow in solutions of up to 2% NaCl. Most of the native rhizobia isolated from L. uliginosus were able to induce nodulation in all plant species studied. In a greenhouse experiment using both D. incanum and L. corniculatus plants, the rhizobia isolate UFRGS Lu2 promoted the greatest plant growth. The results demonstrate that there are native rhizobia in the soils of southern Brazil that have low host specificity and are able to induce nodulation and form active nodules in several plant species.

  3. Distinct changes in soybean xylem sap proteome in response to pathogenic and symbiotic microbe interactions

    Directory of Open Access Journals (Sweden)

    Cho Un-Haing

    2009-09-01

    Full Text Available Abstract Background Plant systemic signaling characterized by the long distance transport of molecules across plant organs involves the xylem and phloem conduits. Root-microbe interactions generate systemic signals that are transported to aerial organs via the xylem sap. We analyzed the xylem sap proteome of soybean seedlings in response to pathogenic and symbiotic interactions to identify systemic signaling proteins and other differentially expressed proteins. Results We observed the increase of a serine protease and peroxidase in the xylem sap in response to Phytophthora sojae elicitor treatment. The high molecular weight fraction of soybean xylem sap was found to promote the growth of Neurospora crassa in vitro at lower concentrations and inhibit growth at higher concentrations. Sap from soybean plants treated with a P. sojae elicitor had a significantly higher inhibitory effect than sap from control soybean plants. When soybean seedlings were inoculated with the symbiont Bradyrhizobium japonicum, the abundance of a xyloglucan transendoglycosyl transferase protein increased in the xylem sap. However, RNAi-mediated silencing of the corresponding gene did not significantly affect nodulation in soybean hairy root composite plants. Conclusion Our study identified a number of sap proteins from soybean that are differentially induced in response to B. japonicum and P. sojae elicitor treatments and a majority of them were secreted proteins.

  4. Symbiotic fermentation, digesta passage, and gastrointestinal morphology in bullfrog tadpoles (Rana catesbeiana).

    Science.gov (United States)

    Pryor, Gregory S; Bjorndal, Karen A

    2005-01-01

    Relative to other herbivorous vertebrates, the nutritional ecology and digestive physiology of anuran larvae remain poorly understood. Our objective was to compare gut structure and inhabitants, digesta passage, and microbial fermentation in bullfrog tadpoles (Rana catesbeiana) to those in other herbivores. Bullfrog tadpole gastrointestinal tracts were long and voluminous, with an enlarged colon that harbored a diverse symbiotic community. The transit time for particulate markers passing through bullfrog tadpoles was 6 h, the median retention time was 8-10 h, and gut clearance was 10-14 h postingestion. Relatively high levels of short-chain fatty acids in the hindgut of tadpoles indicated active microbial fermentation in this gut region. This report represents the first account of gastrointestinal fermentation in the class Amphibia. On the basis of in vitro fermentation assays, we estimated that microbial fermentation in the hindgut provides 20% of the total daily energy requirement of bullfrog tadpoles. These tadpoles also exhibited coprophagy, a practice that provides important nutritive gains in other herbivores. The physiological and behavioral characteristics of these tadpoles are remarkably similar to those of other small-bodied, hindgut-fermenting vertebrates, suggesting convergent digestive strategies among a broad range of herbivorous taxa.

  5. Mapping the Genetic Basis of Symbiotic Variation in Legume-Rhizobium Interactions in Medicago truncatula

    Science.gov (United States)

    Gorton, Amanda J.; Heath, Katy D.; Pilet-Nayel, Marie-Laure; Baranger, Alain

    2012-01-01

    Mutualisms are known to be genetically variable, where the genotypes differ in the fitness benefits they gain from the interaction. To date, little is known about the loci that underlie such genetic variation in fitness or whether the loci influencing fitness are partner specific, and depend on the genotype of the interaction partner. In the legume-rhizobium mutualism, one set of potential candidate genes that may influence the fitness benefits of the symbiosis are the plant genes involved in the initiation of the signaling pathway between the two partners. Here we performed quantitative trait loci (QTL) mapping in Medicago truncatula in two different rhizobium strain treatments to locate regions of the genome influencing plant traits, assess whether such regions are dependent on the genotype of the rhizobial mutualist (QTL × rhizobium strain), and evaluate the contribution of sequence variation at known symbiosis signaling genes. Two of the symbiotic signaling genes, NFP and DMI3, colocalized with two QTL affecting average fruit weight and leaf number, suggesting that natural variation in nodulation genes may potentially influence plant fitness. In both rhizobium strain treatments, there were QTL that influenced multiple traits, indicative of either tight linkage between loci or pleiotropy, including one QTL with opposing effects on growth and reproduction. There was no evidence for QTL × rhizobium strain or genotype × genotype interactions, suggesting either that such interactions are due to small-effect loci or that more genotype-genotype combinations need to be tested in future mapping studies. PMID:23173081

  6. Symbiotic fungi that are essential for plant nutrient uptake investigated with NMP

    Science.gov (United States)

    Pallon, J.; Wallander, H.; Hammer, E.; Arteaga Marrero, N.; Auzelyte, V.; Elfman, M.; Kristiansson, P.; Nilsson, C.; Olsson, P. A.; Wegdén, M.

    2007-07-01

    The nuclear microprobe (NMP) technique using PIXE for elemental analysis and STIM on/off axis for parallel mass density normalization has proven successful to investigate possible interactions between minerals and ectomycorrhizal (EM) mycelia that form symbiotic associations with forest trees. The ability for the EM to make elements biologically available from minerals and soil were compared in field studies and in laboratory experiments, and molecular analysis (PCR-RFLP) was used to identify ectomycorrhizal species from the field samplings. EM rhizomorphs associated with apatite in laboratory systems and in mesh bags incubated in forest ecosystems contained larger amounts of Ca than similar rhizomorphs connected to acid-washed sand. EM mycelium produced in mesh bags had a capacity to mobilize P from apatite-amended sand and a high concentration of K in some rhizomorphs suggests that these fungi are good accumulators of K and may have a significant role in transporting K to trees. Spores formed by arbuscular mycorrhizal (AM) fungi in laboratory cultures were compared with spores formed in saline soils in Tunisia in Northern Africa. We found lower concentrations of P and higher concentrations of Cl in the spores collected from the field than in the spores collected from laboratory cultures. For the case of laboratory cultures, the distribution of e.g. P and K was found to be clearly correlated.

  7. Estimate of symbiotically fixed nitrogen in field grown soybeans using variations in 15N natural abundance

    International Nuclear Information System (INIS)

    Amarger, N.; Durr, J.C.; Bourguignon, C.; Lagacherie, B.; Mariotti, A.; Mariotti, F.

    1979-01-01

    The use of variations in natural abundance of 15 N between nitrogen fixing and non nitrogen fixing soybeans was investigated for quantitative estimate of symbiotic nitrogen fixation. Isotopic analysis of 4 varieties of inoculated and non-inoculated soybeans growing under field conditions, with and without N-fertilizer was determined. It was found that inoculated soybeans had a significantly lower 15 N content than non-inoculated ones. Estimates of the participation of fixed N to the total nitrogen content of inoculated soybeans were calculated from these differences. They were compared to estimates calculated from differences in N yield between inoculated and non-inoculated plants and to the nitrogenase activity, measured by the C 2 H 2 reduction assay over the growing season. Estimates given by the 15 N measurements were correlated with the C 2 H 2 reducing activity but not with the differences in the N yield. This shows that the isotopic composition was dependent on the amount of fixed nitrogen and consequently that the estimates of fixed nitrogen based on natural 15 N abundance should be reliable. The absence of correlation between estimates based on 15 N content and estimates based on N yield was explained by differences in the uptake of soil nitrogen between inoculated and non inoculated soybeans. (Auth.)

  8. Thicker three-dimensional tissue from a "symbiotic recycling system" combining mammalian cells and algae.

    Science.gov (United States)

    Haraguchi, Yuji; Kagawa, Yuki; Sakaguchi, Katsuhisa; Matsuura, Katsuhisa; Shimizu, Tatsuya; Okano, Teruo

    2017-01-31

    In this paper, we report an in vitro co-culture system that combines mammalian cells and algae, Chlorococcum littorale, to create a three-dimensional (3-D) tissue. While the C2C12 mouse myoblasts and rat cardiac cells consumed oxygen actively, intense oxygen production was accounted for by the algae even in the co-culture system. Although cell metabolism within thicker cardiac cell-layered tissues showed anaerobic respiration, the introduction of innovative co-cultivation partially changed the metabolism to aerobic respiration. Moreover, the amount of glucose consumption and lactate production in the cardiac tissues and the amount of ammonia in the culture media decreased significantly when co-cultivated with algae. In the cardiac tissues devoid of algae, delamination was observed histologically, and the release of creatine kinase (CK) from the tissues showed severe cardiac cell damage. On the other hand, the layered cell tissues with algae were observed to be in a good histological condition, with less than one-fifth decline in CK release. The co-cultivation with algae improved the culture condition of the thicker tissues, resulting in the formation of 160 μm-thick cardiac tissues. Thus, the present study proposes the possibility of creating an in vitro "symbiotic recycling system" composed of mammalian cells and algae.

  9. What Powers the 2006 Outburst of the Symbiotic Star BF Cygni?

    Directory of Open Access Journals (Sweden)

    A. Skopal

    2015-02-01

    Full Text Available BF Cygni is a classical symbiotic binary. Its optical light curve occasionally shows outbursts of the Z And-type, whose nature is not well understood. During the 2006 August, BF Cyg underwent the recent outburst, and continues its active phase to the present. The aim of this contribution is to determine the fundamental parameters of the hot component in the binary during the active phase. For this purpose we used a high- and low-resolution optical spectroscopy and the multicolour UBV RCIC photometry. Our photometric monitoring revealed that a high level of the star’s brightness lasts for unusually long time of > 7 years. A sharp violet-shifted absorption component and broad emission wings in the Hα profile developed during the whole active phase. From 2009, our spectra revealed a bipolar ejection from the white dwarf (WD. Modelling the spectral energy distribution (SED of the low-resolution spectra showed simultaneous presence of a warm (< 10 000 K disk-like pseudophotosphere and a strong nebular component of radiation (emission measure of ~1061 cm−3. The luminosity of the hot active object was estimated to > 5−8×103 Lʘ. Such high luminosity, sustained for the time of years, can be understood as a result of an enhanced transient accretion rate throughout a large disk, leading also to formation of collimated ejection from the WD.

  10. Phisicochemical, sensory, and microbiological evaluation and development of symbiotic fermented drink

    Directory of Open Access Journals (Sweden)

    Mônica de Lucena Lira Aguiar Dias

    2013-12-01

    Full Text Available The goal of this study was to develop a symbiotic lacteous drink, evaluate its physicochemical and sensory characteristics, and verify the viability of Lactobacillus acidophilus in the drink. The milk serum-based drink consisted of 50% milk serum containing 10% saccharose, 25% powdered milk, 15% yacon pulp, and cultures of Lactobacillus acidophilus-La 5E and Bifidobacterium bifidum BB12. It was stored for up to 21 days under refrigeration. The milk serum-based drink was analyzed for protein, ether extract, total dietary fiber, total frutans, carbohydrate content, color, pH, acidity, and contamination by coliforms, and Salmonella sp. Coliforms and Salmonella sp were not detected, and L. acidophilus and B. bifidum provided satisfactory probiotic counts up to 21 days of storage under refrigeration. Lactobacillus acidophilus resistance to gastric acids and bile salts was detected only up to seven days of storage when evaluated in vitro. Sensory analysis and purchase viability were evaluated by consumers at 0, 7, 14, and 21 days of storage. Based on the analytical results and consumer evaluation, the drink was acceptable up to seven days of storage.

  11. Genetic diversity and symbiotic compatibility among rhizobial strains and Desmodium incanum and Lotus spp. plants

    Science.gov (United States)

    Granada, Camille E.; Strochein, Marcos; Vargas, Luciano K.; Bruxel, Manuela; de Sá, Enilson Luiz Saccol; Passaglia, Luciane M.P.

    2014-01-01

    This work aimed to evaluate the symbiotic compatibility and nodulation efficiency of rhizobia isolated from Desmodium incanum, Lotus corniculatus, L. subbiflorus, L. uliginosus and L. glaber plants by cross-inoculation. Twelve reference strains and 21 native isolates of rhizobia were genetically analyzed by the BOX-PCR technique, which showed a high genetic diversity among the rhizobia studied. The isolates were also characterized based on their production of indolic compounds and siderophores, as well as on their tolerance to salinity. Fifteen of the 33 rhizobia analyzed were able to produce indolic compounds, whereas 13 produced siderophores. All the tested rhizobia were sensitive to high salinity, although some were able to grow in solutions of up to 2% NaCl. Most of the native rhizobia isolated from L. uliginosus were able to induce nodulation in all plant species studied. In a greenhouse experiment using both D. incanum and L. corniculatus plants, the rhizobia isolate UFRGS Lu2 promoted the greatest plant growth. The results demonstrate that there are native rhizobia in the soils of southern Brazil that have low host specificity and are able to induce nodulation and form active nodules in several plant species. PMID:25071405

  12. api, A novel Medicago truncatula symbiotic mutant impaired in nodule primordium invasion.

    Science.gov (United States)

    Teillet, Alice; Garcia, Joseph; de Billy, Françoise; Gherardi, Michèle; Huguet, Thierry; Barker, David G; de Carvalho-Niebel, Fernanda; Journet, Etienne-Pascal

    2008-05-01

    Genetic approaches have proved to be extremely useful in dissecting the complex nitrogen-fixing Rhizobium-legume endosymbiotic association. Here we describe a novel Medicago truncatula mutant called api, whose primary phenotype is the blockage of rhizobial infection just prior to nodule primordium invasion, leading to the formation of large infection pockets within the cortex of noninvaded root outgrowths. The mutant api originally was identified as a double symbiotic mutant associated with a new allele (nip-3) of the NIP/LATD gene, following the screening of an ethylmethane sulphonate-mutagenized population. Detailed characterization of the segregating single api mutant showed that rhizobial infection is also defective at the earlier stage of infection thread (IT) initiation in root hairs, as well as later during IT growth in the small percentage of nodules which overcome the primordium invasion block. Neither modulating ethylene biosynthesis (with L-alpha-(2-aminoethoxyvinylglycine or 1-aminocyclopropane-1-carboxylic acid) nor reducing ethylene sensitivity in a skl genetic background alters the basic api phenotype, suggesting that API function is not closely linked to ethylene metabolism or signaling. Genetic mapping places the API gene on the upper arm of the M. truncatula linkage group 4, and epistasis analyses show that API functions downstream of BIT1/ERN1 and LIN and upstream of NIP/LATD and the DNF genes.

  13. Symbiotic Navigation in Multi-Robot Systems with Remote Obstacle Knowledge Sharing.

    Science.gov (United States)

    Ravankar, Abhijeet; Ravankar, Ankit A; Kobayashi, Yukinori; Emaru, Takanori

    2017-07-05

    Large scale operational areas often require multiple service robots for coverage and task parallelism. In such scenarios, each robot keeps its individual map of the environment and serves specific areas of the map at different times. We propose a knowledge sharing mechanism for multiple robots in which one robot can inform other robots about the changes in map, like path blockage, or new static obstacles, encountered at specific areas of the map. This symbiotic information sharing allows the robots to update remote areas of the map without having to explicitly navigate those areas, and plan efficient paths. A node representation of paths is presented for seamless sharing of blocked path information. The transience of obstacles is modeled to track obstacles which might have been removed. A lazy information update scheme is presented in which only relevant information affecting the current task is updated for efficiency. The advantages of the proposed method for path planning are discussed against traditional method with experimental results in both simulation and real environments.

  14. Corals hosting symbiotic hydrozoans are less susceptible to predation and disease

    KAUST Repository

    Montano, Simone

    2017-12-20

    In spite of growing evidence that climate change may dramatically affect networks of interacting species, whether-and to what extent-ecological interactions can mediate species\\' responses to disturbances is an open question. Here we show how a largely overseen association such as that between hydrozoans and scleractinian corals could be possibly associated with a reduction in coral susceptibility to ever-increasing predator and disease outbreaks. We examined 2455 scleractinian colonies (from both Maldivian and the Saudi Arabian coral reefs) searching for non-random patterns in the occurrence of hydrozoans on corals showing signs of different health conditions (i.e. bleaching, algal overgrowth, corallivory and different coral diseases). We show that, after accounting for geographical, ecological and co-evolutionary factors, signs of disease and corallivory are significantly lower in coral colonies hosting hydrozoans than in hydrozoan-free ones. This finding has important implications for our understanding of the ecology of coral reefs, and for their conservation in the current scenario of global change, because it suggests that symbiotic hydrozoans may play an active role in protecting their scleractinian hosts from stresses induced by warming water temperatures.

  15. The Symbiotic Food System: An ‘Alternative’ Agri-Food System Already Working at Scale

    Directory of Open Access Journals (Sweden)

    Marc C. A. Wegerif

    2016-08-01

    Full Text Available This article is an analysis of the agri-food system that feeds most of the over four million residents of the fast growing city of Dar es Salaam in Tanzania. It is based on qualitative research that has traced the sources of some important foods from urban eaters back through retailers, processors and transporters to the primary producers. Particular attention is given to the functioning of the market places and how new actors enter into the food system. These reveal that more important to the system than competition are various forms of collaboration. Of particular interest is how a wide range of small-scale and interdependent actors produce the food and get it to urban eaters at a city feeding scale without large vertically- or horizontally-integrated corporate structures. This “symbiotic food system” is an existing alternative to the corporate-dominated agri-business food system; it can and does deliver at scale and in a way that better responds to the needs of people in poverty who are buying food and the interests of food producers. It is not perfect in Dar es Salaam, but the food system is working and is a model that should be built on.

  16. Development and poverty: a symbiotic relationship and its implication in Africa.

    Science.gov (United States)

    Oyeshola, Dokun

    2007-06-10

    Poverty is present everywhere but the kind in Africa is of great magnitude both in its spread and destitutive dimension. In other places any manifestation of poverty is a challenge to move forward but in Africa, the reverse is the case. Therefore the continent and international community are not happy about it, hence various programmes and strategies were put in place. Ironically there is little to show for it. For instance, about ten years before the end of millennium, the common slogan in Africa was 'water for all, food for all, education for all, health for all and so on by the year 2000'. The 'miracle' year 2000 has come and gone and water, food, education and health are not enjoyed by many citizens of the continent. Development is still illusive. In this paper I examine the issues of poverty and development in the context of deforestation/biodiversity a consequent effect of global warming being one of the major threats to humanity. Some questions are raised with a view to proffer recommendations that may move the continent forward. These are: What are the roots of poverty in Africa? Why should there be a symbiotic relationship between poverty and development in Africa? Can Africa really develop?

  17. Evolution of the symbiotic binary system AG Pegasi - The slowest classical nova eruption ever recorded

    Science.gov (United States)

    Kenyon, Scott J.; Mikolajewska, Joanna; Mikolajewski, Maciej; Polidan, Ronald S.; Slovak, Mark H.

    1993-01-01

    We present an analysis of new and existing photometric and spectroscopic observations of the ongoing eruption in the symbiotic star AG Pegasi, showing that this binary has evolved considerably since the turn of the century. Recent dramatic changes in both the UV continuum and the wind from the hot component allow a more detailed analysis than in previous papers. AG Peg is composed of a normal M3 giant and a hot, compact star embedded in a dense, ionized nebula. The hot component powers the activity observed in this system, including a dense wind and a photoionized region within the outer atmosphere of the red giant. The hot component contracted in radius at roughly constant luminosity from 1850 to 1985. Its bolometric luminosity declined by a factor of about 4 during the past 5 yr. Both the mass loss rate from the hot component and the emission activity decreased in step with the hot component's total luminosity, while photospheric radiation from the red giant companion remained essentially constant.

  18. Differential antimicrobial activity of silver nanoparticles to bacteria Bacillus subtilis and Escherichia coli, and toxicity to crop plant Zea mays and beneficial B. subtilis-inoculated Z. mays

    Energy Technology Data Exchange (ETDEWEB)

    Doody, Michael A.; Wang, Dengjun; Bais, Harsh P.; Jin, Yan, E-mail: yjin@udel.edu [University of Delaware, Department of Plant and Soil Sciences (United States)

    2016-10-15

    As silver nanoparticles (AgNPs) have become increasingly used in commercial antimicrobial agents and industrial and military products, concerns are increasing over their broad environmental and health impacts and risks because they are finding their way to the environment. This study was designed to quantify the antimicrobial activity of citrate-coated AgNPs (c-AgNPs; transmission electron microscope size of 44.9 ± 7.2 nm) to two species of bacteria, i.e., Gram-positive Bacillus subtilis and Gram-negative Escherichia coli, and toxicity to a major crop plant Zea mays and beneficial bacteria-inoculated plant (i.e., B. subtilis-inoculated Z. mays symbiont). Our results reveal that the exposure of c-AgNPs significantly inhibited bacteria growth and altered their growth kinetics. Z. mays experienced significant sublethal effects including reduced root length and biomass, and hyper-accumulation of Ag in roots. The beneficial interactions between B. subtilis and Z. mays were weakened as well because both species suffered sublethal effects. Potential mechanisms leading to the antimicrobial activity and toxicity of c-AgNPs to the bacteria, plant, and plant–bacteria symbiont examined in this study were discussed. Taken together, our findings advance the current knowledge of AgNPs antimicrobial property or toxicity to bacteria, crop plant, and beneficial plant–bacteria symbiotic interaction, which is a critical component for NPs environmental impact and risk assessment.Graphical Abstract.

  19. Differential antimicrobial activity of silver nanoparticles to bacteria Bacillus subtilis and Escherichia coli, and toxicity to crop plant Zea mays and beneficial B. subtilis-inoculated Z. mays

    Science.gov (United States)

    Doody, Michael A.; Wang, Dengjun; Bais, Harsh P.; Jin, Yan

    2016-10-01

    As silver nanoparticles (AgNPs) have become increasingly used in commercial antimicrobial agents and industrial and military products, concerns are increasing over their broad environmental and health impacts and risks because they are finding their way to the environment. This study was designed to quantify the antimicrobial activity of citrate-coated AgNPs (c-AgNPs; transmission electron microscope size of 44.9 ± 7.2 nm) to two species of bacteria, i.e., Gram-positive Bacillus subtilis and Gram-negative Escherichia coli, and toxicity to a major crop plant Zea mays and beneficial bacteria-inoculated plant (i.e., B. subtilis-inoculated Z. mays symbiont). Our results reveal that the exposure of c-AgNPs significantly inhibited bacteria growth and altered their growth kinetics. Z. mays experienced significant sublethal effects including reduced root length and biomass, and hyper-accumulation of Ag in roots. The beneficial interactions between B. subtilis and Z. mays were weakened as well because both species suffered sublethal effects. Potential mechanisms leading to the antimicrobial activity and toxicity of c-AgNPs to the bacteria, plant, and plant-bacteria symbiont examined in this study were discussed. Taken together, our findings advance the current knowledge of AgNPs antimicrobial property or toxicity to bacteria, crop plant, and beneficial plant-bacteria symbiotic interaction, which is a critical component for NPs environmental impact and risk assessment.

  20. Differential antimicrobial activity of silver nanoparticles to bacteria Bacillus subtilis and Escherichia coli, and toxicity to crop plant Zea mays and beneficial B. subtilis-inoculated Z. mays

    International Nuclear Information System (INIS)

    Doody, Michael A.; Wang, Dengjun; Bais, Harsh P.; Jin, Yan

    2016-01-01

    As silver nanoparticles (AgNPs) have become increasingly used in commercial antimicrobial agents and industrial and military products, concerns are increasing over their broad environmental and health impacts and risks because they are finding their way to the environment. This study was designed to quantify the antimicrobial activity of citrate-coated AgNPs (c-AgNPs; transmission electron microscope size of 44.9 ± 7.2 nm) to two species of bacteria, i.e., Gram-positive Bacillus subtilis and Gram-negative Escherichia coli, and toxicity to a major crop plant Zea mays and beneficial bacteria-inoculated plant (i.e., B. subtilis-inoculated Z. mays symbiont). Our results reveal that the exposure of c-AgNPs significantly inhibited bacteria growth and altered their growth kinetics. Z. mays experienced significant sublethal effects including reduced root length and biomass, and hyper-accumulation of Ag in roots. The beneficial interactions between B. subtilis and Z. mays were weakened as well because both species suffered sublethal effects. Potential mechanisms leading to the antimicrobial activity and toxicity of c-AgNPs to the bacteria, plant, and plant–bacteria symbiont examined in this study were discussed. Taken together, our findings advance the current knowledge of AgNPs antimicrobial property or toxicity to bacteria, crop plant, and beneficial plant–bacteria symbiotic interaction, which is a critical component for NPs environmental impact and risk assessment.Graphical Abstract

  1. The Symbiotic Performance of Chickpea Rhizobia Can Be Improved by Additional Copies of the clpB Chaperone Gene.

    Directory of Open Access Journals (Sweden)

    Ana Paço

    Full Text Available The ClpB chaperone is known to be involved in bacterial stress response. Moreover, recent studies suggest that this protein has also a role in the chickpea-rhizobia symbiosis. In order to improve both stress tolerance and symbiotic performance of a chickpea microsymbiont, the Mesorhizobium mediterraneum UPM-Ca36T strain was genetically transformed with pPHU231 containing an extra-copy of the clpB gene. To investigate if the clpB-transformed strain displays an improved stress tolerance, bacterial growth was evaluated under heat and acid stress conditions. In addition, the effect of the extra-copies of the clpB gene in the symbiotic performance was evaluated using plant growth assays (hydroponic and pot trials. The clpB-transformed strain is more tolerant to heat shock than the strain transformed with pPHU231, supporting the involvement of ClpB in rhizobia heat shock tolerance. Both plant growth assays showed that ClpB has an important role in chickpea-rhizobia symbiosis. The nodulation kinetics analysis showed a higher rate of nodule appearance with the clpB-transformed strain. This strain also induced a greater number of nodules and, more notably, its symbiotic effectiveness increased ~60% at pH5 and 83% at pH7, compared to the wild-type strain. Furthermore, a higher frequency of root hair curling was also observed in plants inoculated with the clpB-transformed strain, compared to the wild-type strain. The superior root hair curling induction, nodulation ability and symbiotic effectiveness of the clpB-transformed strain may be explained by an increased expression of symbiosis genes. Indeed, higher transcript levels of the nodulation genes nodA and nodC (~3 folds were detected in the clpB-transformed strain. The improvement of rhizobia by addition of extra-copies of the clpB gene may be a promising strategy to obtain strains with enhanced stress tolerance and symbiotic effectiveness, thus contributing to their success as crop inoculants

  2. Money and transmission of bacteria.

    NARCIS (Netherlands)

    Gedik, H.; Voss, T.A.; Voss, A.

    2013-01-01

    Money is one of the most frequently passed items in the world. The aim of this study was to ascertain the survival status of bacteria including Staphylococcus aureus, Escherichia coli, and Vancomycin- Resistant Enterococci (VRE) on banknotes from different countries and the transmission of bacteria

  3. Commonalities and differences of T3SSs in rhizobia and plant pathogenic bacteria

    Science.gov (United States)

    Tampakaki, Anastasia P.

    2014-01-01

    Plant pathogenic bacteria and rhizobia infect higher plants albeit the interactions with their hosts are principally distinct and lead to completely different phenotypic outcomes, either pathogenic or mutualistic, respectively. Bacterial protein delivery to plant host plays an essential role in determining the phenotypic outcome of plant-bacteria interactions. The involvement of type III secretion systems (T3SSs) in mediating animal- and plant-pathogen interactions was discovered in the mid-80's and is now recognized as a multiprotein nanomachine dedicated to trans-kingdom movement of effector proteins. The discovery of T3SS in bacteria with symbiotic lifestyles broadened its role beyond virulence. In most T3SS-positive bacterial pathogens, virulence is largely dependent on functional T3SSs, while in rhizobia the system is dispensable for nodulation and can affect positively or negatively the mutualistic associations with their hosts. This review focuses on recent comparative genome analyses in plant pathogens and rhizobia that uncovered similarities and variations among T3SSs in their genetic organization, regulatory networks and type III secreted proteins and discusses the evolutionary adaptations of T3SSs and type III secreted proteins that might account for the distinguishable phenotypes and host range characteristics of plant pathogens and symbionts. PMID:24723933

  4. Characterization and Identification of Phosphate Solubilizing Bacteria Isolate GPC3.7 from Limestone Mining Region

    Science.gov (United States)

    Fitriyanti, D.; Mubarik, N. R.; Tjahjoleksono, A.

    2017-03-01

    Phosphate (P) are one of major macronutrients needed by plants. P in the soil are present in the organic and inorganic form. The amounts of P in marginal soil can be increased with plant growth promoting rhizobacteria (PGPR). The aim of this study was to characterize and identify P solubilizing bacteria (PSB) isolate GPC3.7 that characteristically could fix N from the soil around limestone mining area. There were 44 PSB isolates found from 15 soil samples around limestone mining area, Blindis mountain, Cirebon. The solubility index of all strain were measured about 0.125 to 2.375 on Pikovskaya media. There were 22 PSB isolates were grown on N-free bromothymol blue (NfB) medium and 19 isolates were grown on Congo Red Agar (CRA) medium. Only 10 isolates were indicated as symbiotic living microorganisms whereas 12 others were categorized as N-free fixing bacteria. Isolate GPC3.7 was chosen to be further observed, based on its P solubility index, N-fixing ability and growth stability. Phosphate quantitative estimation assay of isolate GPC3.7 was unmeasured. The P soluble concentration of GPC3.7 might be lower than 1 mg/L. The colony of GPC3.7 morphologically had round shape, entire margin, raised elevation and white color. Isolate GPC3.7 was Gram negative bacteria with coccus cell shape. Based on 16S rRNA gene, GPC3.7 was closely relative to Acinetobacter baumannii.

  5. Bacteria and yeast microbiota in milk kefir grains from different Italian regions.

    Science.gov (United States)

    Garofalo, Cristiana; Osimani, Andrea; Milanović, Vesna; Aquilanti, Lucia; De Filippis, Francesca; Stellato, Giuseppina; Di Mauro, Simone; Turchetti, Benedetta; Buzzini, Pietro; Ercolini, Danilo; Clementi, Francesca

    2015-08-01

    Kefir grains are a unique symbiotic association of different microrganisms, mainly lactic acid bacteria, yeasts and occasionally acetic acid bacteria, cohabiting in a natural polysaccharide and a protein matrix. The microbial composition of kefir grains can be considered as extremely variable since it is strongly influenced by the geographical origin of the grains and by the sub-culturing method used. The aim of this study was to elucidate the bacteria and yeast species occurring in milk kefir grains collected in some Italian regions by combining the results of scanning electron microscopy analysis, viable counts on selective culture media, PCR-DGGE and pyrosequencing. The main bacterial species found was Lactobacillus kefiranofaciens while Dekkera anomala was the predominant yeast. The presence of sub-dominant species ascribed to Streptococcus thermophilus, Lactococcus lactis and Acetobacter genera was also highlighted. In addition, Lc. lactis, Enterococcus sp., Bacillus sp., Acetobacter fabarum, Acetobacter lovaniensis and Acetobacter orientalis were identified as part of the cultivable community. This work further confirms both the importance of combining culture-independent and culture-dependent approaches to study microbial diversity in food and how the combination of multiple 16S rRNA gene targets strengthens taxonomic identification using sequence-based identification approaches. Copyright © 2015 Elsevier Ltd. All rights reserved.

  6. Motile zoospores of Batrachochytrium dendrobatidis move away from antifungal metabolites produced by amphibian skin bacteria.

    Science.gov (United States)

    Lam, Brianna A; Walton, D Brian; Harris, Reid N

    2011-03-01

    Chytridiomycosis is an amphibian skin disease that threatens amphibian biodiversity worldwide. The fungal agent of chytridiomycosis is Batrachochytrium dendrobatidis. There is considerable variation in disease outcomes such that some individuals and populations co-exist with the fungus and others quickly succumb to disease. Amphibians in populations that co-exist with the B. dendrobatidis have sublethal infections on their skins. Symbiotic skin bacteria have been shown in experiments and surveys to play a role in protecting amphibians from chytridiomycosis. Little is known about the mechanisms that antifungal skin bacteria use to ameliorate the effects of B. dendrobatidis. In this study, we identified that B. dendrobatidis isolate JEL 310 zoospores display chemotaxis, in the presence of two bacterially-produced metabolites (2,4-diacetylphloroglucinol and indole-3-carboxaldehyde). In the presence of either metabolite, B. dendrobatidis zoospores move more frequently away from the metabolite. Using parameters estimated from this study, a simple stochastic model of a random walk on a lattice was evaluated. The model shows that these individual behaviors over short time-scales directly lead to population behaviors over long time-scales, such that most zoospores will escape, or not infect a tryptone substrate containing the bacterially-produced metabolite, whereas many zoospores will infect the tryptone substrate containing no metabolite. These results suggest that amphibians that have skin bacteria produce antifungal metabolites that might be able to keep B. dendrobatidis infections below the lethal threshold and thus are able to co-exist with the fungus.

  7. Using Raman spectroscopy and SERS for in situ studies of rhizosphere bacteria

    Energy Technology Data Exchange (ETDEWEB)

    Mohseni, Hooman; Agahi, Massoud H.; Razeghi, Manijeh; Polisetti, Sneha; Baig, Nameera; Bible, Amber; Morrell-Falvey, Jennifer; Doktycz, Mitchel; Bohn, Paul W.

    2015-08-21

    Bacteria colonize plant roots to form a symbiotic relationship with the plant and can play in important role in promoting plant growth. Raman spectroscopy is a useful technique to study these bacterial systems and the chemical signals they utilize to interact with the plant. We present a Raman study of Pantoea YR343 that was isolated from the rhizosphere of Populus deltoides (Eastern Cottonwood). Pantoea sp. YR343 produce yellowish carotenoid pigment that play a role in protection against UV radiation, in the anti-oxidative pathways and in membrane fluidity. Raman spectroscopy is used to non-invasively characterize the membrane bound carotenoids. The spectra collected from a mutant strain created by knocking out the crtB gene that encodes a phytoene synthase responsible for early stage of carotenoid biosynthesis, lack the carotenoid peaks. Surface Enhanced Raman Spectroscopy is being employed to detect the plant phytoharmone indoleacetic acid that is synthesized by the bacteria. This work describes our recent progress towards utilizing Raman spectroscopy as a label free, non-destructive method of studying plant-bacteria interactions in the rhizosphere.

  8. Motility of electric cable bacteria

    DEFF Research Database (Denmark)

    Bjerg, Jesper Tataru; Damgaard, Lars Riis; Holm, Simon Agner

    2016-01-01

    Cable bacteria are filamentous bacteria that electrically couple sulfide oxidation and oxygen reduction at centimeter distances, and observations in sediment environments have suggested that they are motile. By time-lapse microscopy, we found that cable bacteria used gliding motility on surfaces...... with a highly variable speed of 0.50.3 ms1 (meanstandard deviation) and time between reversals of 155108 s. They frequently moved forward in loops, and formation of twisted loops revealed helical rotation of the filaments. Cable bacteria responded to chemical gradients in their environment, and around the oxic......-anoxic interface, they curled and piled up, with straight parts connecting back to the source of sulfide. Thus, it appears that motility serves the cable bacteria in establishing and keeping optimal connections between their distant electron donor and acceptors in a dynamic sediment environment....

  9. Bioindication of mercury, arsenic and uranium in the apple snail Pomacea canaliculata (Caenogastropoda, Ampullariidae): Bioconcentration and depuration in tissues and symbiotic corpuscles.

    Science.gov (United States)

    Campoy-Diaz, Alejandra D; Arribére, María A; Guevara, Sergio Ribeiro; Vega, Israel A

    2018-04-01

    Pomacea canaliculata is a mollusk potentially useful as a biomonitor species of freshwater quality. This work explores the ability of snail tissues and symbiotic corpuscles to bioconcentrate and depurate mercury, arsenic, and uranium. Adult snails cultured in metal-free reconstituted water were exposed for eight weeks (bioaccumulation phase) to water with Hg (2 μgL -1 ), As (10 μgL -1 ), and U (30 μgL -1 ) and then returned to the reconstituted water for other additional eight weeks (depuration phase). Elemental concentrations in digestive gland, kidney, symbiotic corpuscles and particulate excreta were determined by neutron activation analysis. The glandular symbiotic occupancy was measured by morphometric analysis. After exposure, the kidney showed the highest concentration of Hg, while the digestive gland accumulated mainly As and U. The subcellular distribution in symbiotic corpuscles was ∼71%, ∼48%, and ∼11% for U, Hg, and As, respectively. Tissue depuration between weeks 8 and 16 was variable amongst elements. At week 16, the tissue depuration of U was the highest (digestive gland = 92%; kidney = 80%), while it was lower for Hg (digestive gland = 51%; kidney = 53%). At week 16, arsenic showed a differential pattern of tissue depuration (digestive gland = 23%; kidney = 88%). The symbiotic detoxification of the three elements in excreta was fast between weeks 8 and 10 and it was slower after on. At the end of the depuration, each element distributed differentially in digestive gland and symbiotic corpuscles. Our findings show that symbiotic corpuscles, digestive gland and kidney P. canaliculata are sensitive places for biomonitoring of Hg, As and U. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. METHODS FOR DETECTING BACTERIA USING POLYMER MATERIALS

    NARCIS (Netherlands)

    Van Grinsven Bart Robert, Nicolaas; Cleij, Thomas

    2017-01-01

    A method for characterizing bacteria includes passing a liquid containing an analyte comprising a first bacteria and a second bacteria over and in contact with a polymer material on a substrate. The polymer material is formulated to bind to the first bacteria, and the first bacteria binds to the

  11. Independent origins of vectored plant pathogenic bacteria from arthropod-associated Arsenophonus endosymbionts.

    Science.gov (United States)

    Bressan, Alberto; Terlizzi, Federica; Credi, Rino

    2012-04-01

    The genus Arsenophonus (Gammaproteobacteria) is comprised of intracellular symbiotic bacteria that are widespread across the arthropods. These bacteria can significantly influence the ecology and life history of their hosts. For instance, Arsenophonus nasoniae causes an excess of females in the progeny of parasitoid wasps by selectively killing the male embryos. Other Arsenophonus bacteria have been suspected to protect insect hosts from parasitoid wasps or to expand the host plant range of phytophagous sap-sucking insects. In addition, a few reports have also documented some Arsenophonus bacteria as plant pathogens. The adaptation to a plant pathogenic lifestyle seems to be promoted by the infection of sap-sucking insects in the family Cixiidae, which then transmit these bacteria to plants during the feeding process. In this study, we define the specific localization of an Arsenophonus bacterium pathogenic to sugar beet and strawberry plants within the plant hosts and the insect vector, Pentastiridius leporinus (Hemiptera: Cixiidae), using fluorescence in situ hybridization assays. Phylogenetic analysis on 16S rRNA and nucleotide coding sequences, using both maximum likelihood and Bayesian criteria, revealed that this bacterium is not a sister taxon to "Candidatus Phlomobacter fragariae," a previously characterized Arsenophonus bacterium pathogenic to strawberry plants in France and Japan. Ancestral state reconstruction analysis indicated that the adaptation to a plant pathogenic lifestyle likely evolved from an arthropod-associated lifestyle and showed that within the genus Arsenophonus, the plant pathogenic lifestyle arose independently at least twice. We also propose a novel Candidatus status, "Candidatus Arsenophonus phytopathogenicus" novel species, for the bacterium associated with sugar beet and strawberry diseases and transmitted by the planthopper P. leporinus.

  12. Exploring bacteria-induced growth and morphogenesis in the green macroalga order Ulvales (Chlorophyta

    Directory of Open Access Journals (Sweden)

    Thomas eWichard

    2015-03-01

    Full Text Available Green macroalgae, such as Ulvales, lose their typical morphology completely when grown under axenic conditions or in the absence of the appropriate microbiome. As a result, slow growing aberrant phenotypes or even callus-like morphotypes are observed in Ulvales. The cross-kingdom interactions between marine algae and microorganisms are hence not only restricted by the exchange of macronutrients, including vitamins and nutrients, but also by infochemicals such as bacterial morphogenetic compounds. The latter are a fundamental trait mediating the mutualism within the chemosphere where the organisms interact with each other via compounds in their surroundings.Approximately 60 years ago, pilot studies demonstrated that certain bacteria promote growth, whereas other bacteria induce morphogenesis; this is particularly true for the order of Ulvales. However, only slow progress was made towards the underlying mechanism due to the complexity of, for example, algal cultivation techniques, and the lack of standardized experiments in the laboratory.A breakthrough in this research was the discovery of the morphogenetic compound thallusin, which was isolated from an epiphytic bacterium and induces normal germination and restores the foliaceous morphotypes of Monostroma. Owing to the low concentration, the purification and structure elucidation of highly biologically active morphogenetic compounds is still challenging. Recently, it was found that only the combination of two specific bacteria from the Rhodobacteraceae and Flavobacteriaceae can completely recover the growth and morphogenesis of axenic Ulva mutabilis cultures forming a symbiotic tripartite community by chemical communication.This review combines literature detailing evidence of bacteria-induced morphogenesis in Ulvales. A set of standardized experimental approaches is further proposed for the preparation of axenic algal tissues, bacteria isolation, co-cultivation experiments, and the analysis of

  13. Exploring bacteria-induced growth and morphogenesis in the green macroalga order Ulvales (Chlorophyta)

    Science.gov (United States)

    Wichard, Thomas

    2015-01-01

    Green macroalgae, such as Ulvales, lose their typical morphology completely when grown under axenic conditions or in the absence of the appropriate microbiome. As a result, slow growing aberrant phenotypes or even callus-like morphotypes are observed in Ulvales. The cross-kingdom interactions between marine algae and microorganisms are hence not only restricted by the exchange of macronutrients, including vitamins and nutrients, but also by infochemicals such as bacterial morphogenetic compounds. The latter are a fundamental trait mediating the mutualism within the chemosphere where the organisms interact with each other via compounds in their surroundings. Approximately 60 years ago, pilot studies demonstrated that certain bacteria promote growth, whereas other bacteria induce morphogenesis; this is particularly true for the order of Ulvales. However, only slow progress was made towards the underlying mechanism due to the complexity of, for example, algal cultivation techniques, and the lack of standardized experiments in the laboratory. A breakthrough in this research was the discovery of the morphogenetic compound thallusin, which was isolated from an epiphytic bacterium and induces normal germination restoring the foliaceous morphotypes of Monostroma. Owing to the low concentration, the purification and structure elucidation of highly biologically active morphogenetic compounds are still challenging. Recently, it was found that only the combination of two specific bacteria from the Rhodobacteraceae and Flavobacteriaceae can completely recover the growth and morphogenesis of axenic Ulva mutabilis cultures forming a symbiotic tripartite community by chemical communication. This review combines literature detailing evidences of bacteria-induced morphogenesis in Ulvales. A set of standardized experimental approaches is further proposed for the preparation of axenic algal tissues, bacteria isolation, co-cultivation experiments, and the analysis of the chemosphere

  14. Interactions between diatoms and bacteria.

    Science.gov (United States)

    Amin, Shady A; Parker, Micaela S; Armbrust, E Virginia

    2012-09-01

    Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding higher trophic levels. Here we present an overview of how diatoms and bacteria interact and the implications of these interactions. We emphasize that heterotrophic bacteria in the oceans that are consistently associated with diatoms are confined to two phyla. These consistent bacterial associations result from encounter mechanisms that occur within a microscale environment surrounding a diatom cell. We review signaling mechanisms that occur in this microenvironment to pave the way for specific interactions. Finally, we discuss known interactions between diatoms and bacteria and exciting new directions and research opportunities in this field. Throughout the review, we emphasize new technological advances that will help in the discovery of new interactions. Deciphering the languages of diatoms and bacteria and how they interact will inform our understanding of the role these organisms have in shaping the ocean and how these interactions may change in future oceans.

  15. Interactions between Diatoms and Bacteria

    Science.gov (United States)

    Amin, Shady A.; Parker, Micaela S.

    2012-01-01

    Summary: Diatoms and bacteria have cooccurred in common habitats for hundreds of millions of years, thus fostering specific associations and interactions with global biogeochemical consequences. Diatoms are responsible for one-fifth of the photosynthesis on Earth, while bacteria remineralize a large portion of this fixed carbon in the oceans. Through their coexistence, diatoms and bacteria cycle nutrients between oxidized and reduced states, impacting bioavailability and ultimately feeding higher trophic levels. Here we present an overview of how diatoms and bacteria interact and the implications of these interactions. We emphasize that heterotrophic bacteria in the oceans that are consistently associated with diatoms are confined to two phyla. These consistent bacterial associations result from encounter mechanisms that occur within a microscale environment surrounding a diatom cell. We review signaling mechanisms that occur in this microenvironment to pave the way for specific interactions. Finally, we discuss known interactions between diatoms and bacteria and exciting new directions and research opportunities in this field. Throughout the review, we emphasize new technological advances that will help in the discovery of new interactions. Deciphering the languages of diatoms and bacteria and how they interact will inform our understanding of the role these organisms have in shaping the ocean and how these interactions may change in future oceans. PMID:22933565

  16. Symbiotic Interplay of Fungi, Algae, and Bacteria within the Lung Lichen Lobaria pulmonaria L. Hoffm. as Assessed by State-of-the-Art Metaproteomics.

    Science.gov (United States)

    Eymann, Christine; Lassek, Christian; Wegner, Uwe; Bernhardt, Jörg; Fritsch, Ole Arno; Fuchs, Stephan; Otto, Andreas; Albrecht, Dirk; Schiefelbein, Ulf; Cernava, Tomislav; Aschenbrenner, Ines; Berg, Gabriele; Grube, Martin; Riedel, Katharina

    2017-06-02

    Lichens are recognized by macroscopic structures formed by a heterotrophic fungus, the mycobiont, which hosts internal autotrophic photosynthetic algal and/or cyanobacterial partners, referred to as the photobiont. We analyzed the structure and functionality of the entire lung lichen Lobaria pulmonaria L. Hoffm. collected from two different sites by state-of-the-art metaproteomics. In addition to the green algae and the ascomycetous fungus, a lichenicolous fungus as well as a complex prokaryotic community (different from the cyanobacteria) was found, the latter dominated by methanotrophic Rhizobiales. Various partner-specific proteins could be assigned to the different lichen symbionts, for example, fungal proteins involved in vesicle transport, algal proteins functioning in photosynthesis, cyanobacterial nitrogenase and GOGAT involved in nitrogen fixation, and bacterial enzymes responsible for methanol/C1-compound metabolism as well as CO-detoxification. Structural and functional information on proteins expressed by the lichen community complemented and extended our recent symbiosis model depicting the functional multiplayer network of single holobiont partners.1 Our new metaproteome analysis strongly supports the hypothesis (i) that interactions within the self-supporting association are multifaceted and (ii) that the strategy of functional diversification within the single lichen partners may support the longevity of L. pulmonaria under certain ecological conditions.

  17. An effect of 16S rRNA intercistronic variability on coevolutionary analysis in symbiotic bacteria: Molecular phylogeny of Arsenophonus triatominarum

    Czech Academy of Sciences Publication Activity Database

    Šorfová, Pavlína; Škeříková, Andrea; Hypša, Václav

    2008-01-01

    Roč. 31, č. 2 (2008), s. 88-100 ISSN 0723-2020 R&D Projects: GA ČR GA206/04/0520; GA AV ČR IAA601410708 Institutional research plan: CEZ:AV0Z60220518 Keywords : intragenomic heterogeneity * 16S rRNA * coevolution * insect symbionts * molecular phylogeny Subject RIV: EE - Microbiology, Virology Impact factor: 2.582, year: 2008

  18. Soybean nodulation and symbiotic nitrogen fixation in response to soil compaction and mulching

    Science.gov (United States)

    Siczek, A.; Lipiec, J.

    2009-04-01

    Symbiotic nitrogen fixation by legume crops such as soybean plays a key role in supplying nitrogen for agricultural systems. In symbiotic associations with Bradyrhizobium japonicum soybean can fix up to 200 kg N ha-1 yr-1. This reduces the need for expensive and often environmentally harmful because of leaching nitrogen fertilization. However both soybean nodulation and nitrogen fixation are sensitive to soil conditions. One of the critical soil constraints is soil compaction. Increasing use of heavy equipment and intensive cropping in modern agriculture leads to excessive soil compaction. Compaction often is found as a result of field operations that have to be performed in a very short period of time and when soils are wet and more susceptible to compaction. This results in unfavourable water content, temperature, aeration, pore size distribution, strength for plant growth and microbial activity. The surface mulching can alleviate the adverse effect of the environmental factors on soil by decreasing fluctuation of soil temperature, increasing moisture by controlling evaporation from the soil surface, decreasing bulk density, preventing soil crusting. The effect of mulch on soil conditions largely depends on soil compaction and weather conditions during growing season. The positive effect of the straw mulch on soil moisture has been seen under seasons with insufficient rainfalls. However thicker layers of mulch can act as diffusion barrier, especially when the mulch is wet. Additionally, low soil temperature prevalent during early spring under mulch can impede development of nodule, nodule size and delay onset of nodulation. The aim of this study was to determine the effect of the straw mulch on nodulation and nitrogen fixation of soybean in variously compacted soil. The experimental field was 192 m2and was divided into three parts composed of 6 micro-plots with area 7 m2. Three degrees of soil compaction obtained in each field part through tractor passes were

  19. Diversity and Symbiotic Characteristics of Cowpea Bradyrhizobium Strains in Ghanaian Soils

    International Nuclear Information System (INIS)

    Fening, Joseph Opoku

    1999-08-01

    . Analysis of the 16S rRNA gene of the isolates by PCR-RFLP identified 20 different composite genotypes. Diversity among the genomic species identified was very high, reaching 80% diversity. The various methods used indicated large diversity among the isolates, but the groupings of the isolates by the various methods were inconsistent, due to the different levels of resolution by the various methods. Diversity of the isolates in symbiotic effectiveness showed that some of the isolates had high nitrogen fixing capabilities that were comparable to plants fertilized with inorganic fertilizer nitrogen. Some of the isolates even showed superiority in symbiotic effectiveness relative to the standard strain TAL 169, suggesting that the native isolates may be useful strains for cowpea inoculation. The Gus A marker gene technique was used to assess the competitive abilities of the effective and ineffective isolates. Competition between the isolates was examined at different population ratios. The results obtained indicated that competitive ability was not directly related to effectiveness of strains. Inoculation of cowpea with indigenous bradyrhizobia isolates increased the number of nodules, shoot dry weight and total nitrogen of plants. The method of inoculation was observed to influence these parameters The results indicated that response of cowpea to inoculation in the presence of native rhizobia in some soils is possible. (au)

  20. Differential expression patterns of non-symbiotic hemoglobins in sugar beet (Beta vulgaris ssp. vulgaris).

    Science.gov (United States)

    Leiva-Eriksson, Nélida; Pin, Pierre A; Kraft, Thomas; Dohm, Juliane C; Minoche, André E; Himmelbauer, Heinz; Bülow, Leif

    2014-04-01

    Biennial sugar beet (Beta vulgaris spp. vulgaris) is a Caryophyllidae that has adapted its growth cycle to the seasonal temperature and daylength variation of temperate regions. This is the first time a holistic study of the expression pattern of non-symbiotic hemoglobins (nsHbs) is being carried out in a member of this group and under two essential environmental conditions for flowering, namely vernalization and length of photoperiod. BvHb genes were identified by sequence homology searches against the latest draft of the sugar beet genome. Three nsHb genes (BvHb1.1, BvHb1.2 and BvHb2) and one truncated Hb gene (BvHb3) were found in the genome of sugar beet. Gene expression profiling of the nsHb genes was carried out by quantitative PCR in different organs and developmental stages, as well as during vernalization and under different photoperiods. BvHb1.1 and BvHb2 showed differential expression during vernalization as well as during long and short days. The high expression of BvHb2 indicates that it has an active role in the cell, maybe even taking over some BvHb1.2 functions, except during germination where BvHb1.2 together with BvHb1.1-both Class 1 nsHbs-are highly expressed. The unprecedented finding of a leader peptide at the N-terminus of BvHb1.1, for the first time in an nsHb from higher plants, together with its observed expression indicate that it may have a very specific role due to its suggested location in chloroplasts. Our findings open up new possibilities for research, breeding and engineering since Hbs could be more involved in plant development than previously was anticipated.