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

Directory of Open Access Journals (Sweden)

de Beer Z Wilhelm

2007-07-01

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

Horizontal transfer of facultative endosymbionts is limited by host relatedness.

Science.gov (United States)

Łukasik, Piotr; Guo, Huifang; van Asch, Margriet; Henry, Lee M; Godfray, H Charles J; Ferrari, Julia

2015-10-01

Heritable microbial symbionts can have important effects on many aspects of their hosts' biology. Acquisition of a novel symbiont strain can provide fitness benefits to the host, with significant ecological and evolutionary consequences. We measured barriers to horizontal transmission by artificially transferring facultative symbionts from the grain aphid, Sitobion avenae, and five other aphid species into two clonal genotypes of S. avenae. We found the symbiont Hamiltonella defensa establishes infections more easily following a transfer from the same host species and that such infections are more stable. Infection success was also higher when the introduced symbiont strain was more closely related to the strain that was originally present in the host (but which had previously been removed). There were no differences among successfully established symbiont strains in their effect on aphid fecundity. Hamiltonella defensa did not confer protection against parasitoids in our S. avenae clones, although it often does in other aphid hosts. However, strains of the symbiont Regiella insecticola originating from two host species protected grain aphids against the pathogenic fungus Pandora neoaphidis. This study helps describe the extent to which facultative symbionts can act as a pool of adaptations that can be sampled by their eukaryote hosts. © 2015 The Author(s). Evolution © 2015 The Society for the Study of Evolution.

Why Do Corals Bleach? Conflict and Conflict Mediation in a Host/Symbiont Community.

Science.gov (United States)

Blackstone, Neil W; Golladay, Jeff M

2018-06-26

Coral bleaching has attracted considerable study, yet one central question remains unanswered: given that corals and their Symbiodinium symbionts have co-evolved for millions of years, why does this clearly maladaptive process occur? Bleaching may result from evolutionary conflict between the host corals and their symbionts. Selection at the level of the individual symbiont favors using the products of photosynthesis for selfish replication, while selection at the higher level favors using these products for growth of the entire host/symbiont community. To hold the selfish lower-level units in check, mechanisms of conflict mediation must evolve. Fundamental features of photosynthesis have been co-opted into conflict mediation so that symbionts that fail to export these products produce high levels of reactive oxygen species and undergo programmed cell death. These mechanisms function very well under most environmental conditions, but under conditions particularly detrimental to photosynthesis, it is these mechanisms of conflict mediation that trigger bleaching. © 2018 WILEY Periodicals, Inc.

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

Directory of Open Access Journals (Sweden)

Damar Bayu Murti

2016-06-01

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

Identification of Spiroplasma insolitum symbionts in Anopheles gambiae [version 1; referees: 2 approved, 1 not approved

Directory of Open Access Journals (Sweden)

Sharon T. Chepkemoi

2017-09-01

Full Text Available Background: Insect symbionts have the potential to block the transmission of vector-borne diseases by their hosts. The advancement of a symbiont-based transmission blocking strategy for malaria requires the identification and study of Anopheles symbionts. Methods: High throughput 16S amplicon sequencing was used to profile the bacteria associated with Anopheles gambiae sensu lato and identify potential symbionts. The polymerase chain reaction (PCR with specific primers were subsequently used to monitor symbiont prevalence in field populations, as well as symbiont transmission patterns. Results: We report the discovery of the bacterial symbiont, Spiroplasma, in Anopheles gambiae in Kenya. We determine that geographically dispersed Anopheles gambiae populations in Kenya are infected with Spiroplasma at low prevalence levels. Molecular phylogenetics indicates that this Anopheles gambiae associated Spiroplasma is a member of the insolitum clade. We demonstrate that this symbiont is stably maternally transmitted across at least two generations and does not significantly affect the fecundity or egg to adult survival of its host. Conclusions: In diverse insect species, Spiroplasma has been found to render their host resistant to infection by pathogens. The identification of a maternally transmitted strain of Spiroplasma in Anopheles gambiae may therefore open new lines of investigation for the development of symbiont-based strategies for blocking malaria transmission.

Understanding regulation of the host-mediated gut symbiont population and the symbiont-mediated host immunity in the Riptortus-Burkholderia symbiosis system.

Science.gov (United States)

Kim, Jiyeun Kate; Lee, Jun Beom; Jang, Ho Am; Han, Yeon Soo; Fukatsu, Takema; Lee, Bok Luel

2016-11-01

Valuable insect models have tremendously contributed to our understanding of innate immunity and symbiosis. Bean bug, Riptortus pedestris, is a useful insect symbiosis model due to harboring cultivable monospecific gut symbiont, genus Burkholderia. Bean bug is a hemimetabolous insect whose immunity is not well-understood. However, we recently identified three major antimicrobial peptides of Riptortus and examined the relationship between gut symbiosis and host immunity. We found that the presence of Burkholderia gut symbiont positively affects Riptortus immunity. From studying host regulation mechanisms of symbiont population, we revealed that the symbiotic Burkholderia cells are much more susceptible to Riptortus immune responses than the cultured cells. We further elucidated that the immune-susceptibility of the Burkholderia gut symbionts is due to the drastic change of bacterial cell envelope. Finally, we show that the immune-susceptible Burkholderia symbionts are able to prosper in host owing to the suppression of immune responses of the symbiotic midgut. Copyright © 2016 Elsevier Ltd. All rights reserved.

Measuring concept relatedness using language models

NARCIS (Netherlands)

Trieschnigg, D.; Meij, E.; de Rijke, M.; Kraaij, W.; Myang, S.-H.; Oard, D.W.; Sebastiani, F.; Chua, T.-S.; Leong, M.-K.

2008-01-01

Over the years, the notion of concept relatedness has attracted considerable attention. A variety of approaches, based on ontology structure, information content, association, or context have been proposed to indicate the relatedness of abstract ideas. We propose a method based on the cross entropy

Benchmarking Relatedness Inference Methods with Genome-Wide Data from Thousands of Relatives.

Science.gov (United States)

Ramstetter, Monica D; Dyer, Thomas D; Lehman, Donna M; Curran, Joanne E; Duggirala, Ravindranath; Blangero, John; Mezey, Jason G; Williams, Amy L

2017-09-01

Inferring relatedness from genomic data is an essential component of genetic association studies, population genetics, forensics, and genealogy. While numerous methods exist for inferring relatedness, thorough evaluation of these approaches in real data has been lacking. Here, we report an assessment of 12 state-of-the-art pairwise relatedness inference methods using a data set with 2485 individuals contained in several large pedigrees that span up to six generations. We find that all methods have high accuracy (92-99%) when detecting first- and second-degree relationships, but their accuracy dwindles to 76% of relative pairs. Overall, the most accurate methods are Estimation of Recent Shared Ancestry (ERSA) and approaches that compute total IBD sharing using the output from GERMLINE and Refined IBD to infer relatedness. Combining information from the most accurate methods provides little accuracy improvement, indicating that novel approaches, such as new methods that leverage relatedness signals from multiple samples, are needed to achieve a sizeable jump in performance. Copyright © 2017 Ramstetter et al.

Diversity and Phylogenetic Analyses of Bacterial Symbionts in Three Whitefly Species from Southeast Europe

Science.gov (United States)

Skaljac, Marisa; Zanic, Katja; Puizina, Jasna; Lepen Pleic, Ivana; Ghanim, Murad

2017-01-01

Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood), and Siphoninus phillyreae (Haliday) are whitefly species that harm agricultural crops in many regions of the world. These insects live in close association with bacterial symbionts that affect host fitness and adaptation to the environment. In the current study, we surveyed the infection of whitefly populations in Southeast Europe by various bacterial symbionts and performed phylogenetic analyses on the different symbionts detected. Arsenophonus and Hamiltonella were the most prevalent symbionts in all three whitefly species. Rickettsia was found to infect mainly B. tabaci, while Wolbachia mainly infected both B. tabaci and S. phillyreae. Furthermore, Cardinium was rarely found in the investigated whitefly populations, while Fritschea was never found in any of the whitefly species tested. Phylogenetic analyses revealed a diversity of several symbionts (e.g., Hamiltonella, Arsenophonus, Rickettsia), which appeared in several clades. Reproductively isolated B. tabaci and T. vaporariorum shared the same (or highly similar) Hamiltonella and Arsenophonus, while these symbionts were distinctive in S. phillyreae. Interestingly, Arsenophonus from S. phillyreae did not cluster with any of the reported sequences, which could indicate the presence of Arsenophonus, not previously associated with whiteflies. In this study, symbionts (Wolbachia, Rickettsia, and Cardinium) known to infect a wide range of insects each clustered in the same clades independently of the whitefly species. These results indicate horizontal transmission of bacterial symbionts between reproductively isolated whitefly species, a mechanism that can establish new infections that did not previously exist in whiteflies. PMID:29053633

Diversity and Phylogenetic Analyses of Bacterial Symbionts in Three Whitefly Species from Southeast Europe

Directory of Open Access Journals (Sweden)

Marisa Skaljac

2017-10-01

Full Text Available Bemisia tabaci (Gennadius, Trialeurodes vaporariorum (Westwood, and Siphoninus phillyreae (Haliday are whitefly species that harm agricultural crops in many regions of the world. These insects live in close association with bacterial symbionts that affect host fitness and adaptation to the environment. In the current study, we surveyed the infection of whitefly populations in Southeast Europe by various bacterial symbionts and performed phylogenetic analyses on the different symbionts detected. Arsenophonus and Hamiltonella were the most prevalent symbionts in all three whitefly species. Rickettsia was found to infect mainly B. tabaci, while Wolbachia mainly infected both B. tabaci and S. phillyreae. Furthermore, Cardinium was rarely found in the investigated whitefly populations, while Fritschea was never found in any of the whitefly species tested. Phylogenetic analyses revealed a diversity of several symbionts (e.g., Hamiltonella, Arsenophonus, Rickettsia, which appeared in several clades. Reproductively isolated B. tabaci and T. vaporariorum shared the same (or highly similar Hamiltonella and Arsenophonus, while these symbionts were distinctive in S. phillyreae. Interestingly, Arsenophonus from S. phillyreae did not cluster with any of the reported sequences, which could indicate the presence of Arsenophonus, not previously associated with whiteflies. In this study, symbionts (Wolbachia, Rickettsia, and Cardinium known to infect a wide range of insects each clustered in the same clades independently of the whitefly species. These results indicate horizontal transmission of bacterial symbionts between reproductively isolated whitefly species, a mechanism that can establish new infections that did not previously exist in whiteflies.

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.

Potential applications of insect symbionts in biotechnology.

Science.gov (United States)

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

2016-02-01

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

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

Science.gov (United States)

Fujita, K.; Hikami, M.; Suzuki, A.; Kuroyanagi, A.; Sakai, K.; Kawahata, H.; Nojiri, Y.

2011-08-01

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

Peers and teachers as sources of relatedness perceptions, motivation, and affective responses in physical education.

Science.gov (United States)

Cox, Anne; Duncheon, Nicole; McDavid, Lindley

2009-12-01

Research has demonstrated the importance of relatedness perceptions to self-determined motivation in physical education. Therefore, studies have begun to examine the social factors contributing to feelings of relatedness. The purpose of this study was to examine teacher (perceived emotional support) and peer (acceptance, friendship quality) relationship variables to feelings of relatedness, motivation, and affective responses in junior high physical education students (N = 411). Results revealed that perceived relatedness mediated the relationship between variables and self-determined motivation and related directly to the amount of enjoyment and worry students experienced. These findings demonstrate that relationships with both teachers and peers are important for students' relatedness perceptions, motivation, enjoyment, and worry in physical education.

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

DEFF Research Database (Denmark)

Kumala, Lars; Hentschel, Ute; Bayer, Kristina

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

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

Directory of Open Access Journals (Sweden)

Pages Sylvie

2006-09-01

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

Horizontal transmission of the insect symbiont Rickettsia is plant-mediated

Science.gov (United States)

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

2012-01-01

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

Tracking transmission of apicomplexan symbionts in diverse Caribbean corals.

Directory of Open Access Journals (Sweden)

Nathan L Kirk

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

Tracking transmission of apicomplexan symbionts in diverse Caribbean corals.

Science.gov (United States)

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

2013-01-01

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

Quantification of bacterial and archaeal symbionts in high and low microbial abundance sponges using real-time PCR

KAUST Repository

Bayer, Kristina

2014-07-09

In spite of considerable insights into the microbial diversity of marine sponges, quantitative information on microbial abundances and community composition remains scarce. Here, we established qPCR assays for the specific quantification of four bacterial phyla of representative sponge symbionts as well as the kingdoms Eubacteria and Archaea. We could show that the 16S rRNA gene numbers of Archaea, Chloroflexi, and the candidate phylum Poribacteria were 4-6 orders of magnitude higher in high microbial abundance (HMA) than in low microbial abundance (LMA) sponges and that actinobacterial 16S rRNA gene numbers were 1-2 orders higher in HMA over LMA sponges, while those for Cyanobacteria were stable between HMA and LMA sponges. Fluorescence in situ hybridization of Aplysina aerophoba tissue sections confirmed the numerical dominance of Chloroflexi, which was followed by Poribacteria. Archaeal and actinobacterial cells were detected in much lower numbers. By use of fluorescence-activated cell sorting as a primer- and probe-independent approach, the dominance of Chloroflexi, Proteobacteria, and Poribacteria in A. aerophoba was confirmed. Our study provides new quantitative insights into the microbiology of sponges and contributes to a better understanding of the HMA/LMA dichotomy. The authors quantified sponge symbionts in eight sponge species from three different locations by real time PCR targetting 16S rRNA genes. Additionally, FISH was performed and diversity and abundance of singularized microbial symbionts from Aplysina aerophoba was determined for a comprehensive quantification work. © 2014 Federation of European Microbiological Societies.

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

Directory of Open Access Journals (Sweden)

Helen E Dunbar

2007-05-01

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

Symbiont modulates expression of specific gene categories in Angomonas deanei

Directory of Open Access Journals (Sweden)

Luciana Loureiro Penha

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

Aphid facultative symbionts reduce survival of the predatory lady beetle Hippodamia convergens

Science.gov (United States)

2014-01-01

Background Non-essential facultative endosymbionts can provide their hosts with protection from parasites, pathogens, and predators. For example, two facultative bacterial symbionts of the pea aphid (Acyrthosiphon pisum), Serratia symbiotica and Hamiltonella defensa, protect their hosts from parasitism by two species of parasitoid wasp. Previous studies have not explored whether facultative symbionts also play a defensive role against predation in this system. We tested whether feeding on aphids harboring different facultative symbionts affected the fitness of an aphid predator, the lady beetle Hippodamia convergens. Results While these aphid faculative symbionts did not deter lady beetle feeding, they did decrease survival of lady beetle larvae. Lady beetle larvae fed a diet of aphids with facultative symbionts had significantly reduced survival from egg hatching to pupation and therefore had reduced survival to adult emergence. Additionally, lady beetle adults fed aphids with facultative symbionts were significantly heavier than those fed facultative symbiont-free aphids, though development time was not significantly different. Conclusions Aphids reproduce clonally and are often found in large groups. Thus, aphid symbionts, by reducing the fitness of the aphid predator H. convergens, may indirectly defend their hosts’ clonal descendants against predation. These findings highlight the often far-reaching effects that symbionts can have in ecological systems. PMID:24555501

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

Science.gov (United States)

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

2014-06-01

Herbivorous insects frequently harbor bacterial symbionts that affect their ecology and evolution. Aphids host the obligatory endosymbiont Buchnera, which is required for reproduction, together with facultative symbionts whose frequencies vary across aphid populations. These maternally transmitted secondary symbionts have been particularly studied in the pea aphid, Acyrthosiphon pisum, which harbors at least 8 distinct bacterial species (not counting Buchnera) having environmentally dependent effects on host fitness. In particular, these symbiont species are associated with pea aphid populations feeding on specific plants. Although they are maternally inherited, these bacteria are occasionally transferred across insect lineages. One mechanism of such nonmaternal transfer is paternal transmission to the progeny during sexual reproduction. To date, transmission of secondary symbionts during sexual reproduction of aphids has been investigated in only a handful of aphid lineages and 3 symbiont species. To better characterize this process, we investigated inheritance patterns of 7 symbiont species during sexual reproduction of pea aphids through a crossing experiment involving 49 clones belonging to 9 host-specialized biotypes, and 117 crosses. Symbiont species in the progeny were detected with diagnostic qualitative PCR at the fundatrix stage hatching from eggs and in later parthenogenetic generations. We found no confirmed case of paternal transmission of symbionts to the progeny, and we observed that maternal transmission of a particular symbiont species (Serratia symbiotica) was quite inefficient. We discuss these observations in respect to the ecology of the pea aphid. © 2013 Institute of Zoology, Chinese Academy of Sciences.

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

KAUST Repository

Ziegler, Maren; Roder, Cornelia; Bü chel, C; Voolstra, Christian R.

2015-01-01

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

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

KAUST Repository

Ziegler, Maren

2015-08-06

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

Parasitic wasp responses to symbiont-based defense in aphids

Directory of Open Access Journals (Sweden)

Oliver Kerry M

2012-02-01

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

Industry Relatedness and Post-Acquisition Innovative Performance

DEFF Research Database (Denmark)

Cefis, Elena; Marsili, Orietta; Rigamonti, Damiana

2015-01-01

This paper examines how characteristics of acquiring and acquired firms influence the curvilinear (inverted U-shaped) relationship between relatedness and post-acquisition innovative performance. Using a relatedness index based on industry co-occurrence in a sample of 1,736 Dutch acquisitions, we...... find that acquirer's internal R&D and acquisition experience, and the small size of acquired firms, help to reach a balance between exploration of novelty and exploitation of synergies in unrelated acquisitions, and to achieve higher post-acquisition performance. However, while the acquirer's R......&D increases flexibility in the acquisition process in presence of deviations from the optimal level of relatedness, acquisition experience may enhance rigidities....

Relatedness, conflict, and the evolution of eusociality.

Directory of Open Access Journals (Sweden)

Xiaoyun Liao

2015-03-01

Full Text Available The evolution of sterile worker castes in eusocial insects was a major problem in evolutionary theory until Hamilton developed a method called inclusive fitness. He used it to show that sterile castes could evolve via kin selection, in which a gene for altruistic sterility is favored when the altruism sufficiently benefits relatives carrying the gene. Inclusive fitness theory is well supported empirically and has been applied to many other areas, but a recent paper argued that the general method of inclusive fitness was wrong and advocated an alternative population genetic method. The claim of these authors was bolstered by a new model of the evolution of eusociality with novel conclusions that appeared to overturn some major results from inclusive fitness. Here we report an expanded examination of this kind of model for the evolution of eusociality and show that all three of its apparently novel conclusions are essentially false. Contrary to their claims, genetic relatedness is important and causal, workers are agents that can evolve to be in conflict with the queen, and eusociality is not so difficult to evolve. The misleading conclusions all resulted not from incorrect math but from overgeneralizing from narrow assumptions or parameter values. For example, all of their models implicitly assumed high relatedness, but modifying the model to allow lower relatedness shows that relatedness is essential and causal in the evolution of eusociality. Their modeling strategy, properly applied, actually confirms major insights of inclusive fitness studies of kin selection. This broad agreement of different models shows that social evolution theory, rather than being in turmoil, is supported by multiple theoretical approaches. It also suggests that extensive prior work using inclusive fitness, from microbial interactions to human evolution, should be considered robust unless shown otherwise.

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

Directory of Open Access Journals (Sweden)

Zhou Xuguo

2009-10-01

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

Co-invading symbiotic mutualists of Medicago polymorpha retain high ancestral diversity and contain diverse accessory genomes.

Science.gov (United States)

Porter, Stephanie S; Faber-Hammond, Joshua J; Friesen, Maren L

2018-01-01

Exotic, invasive plants and animals can wreak havoc on ecosystems by displacing natives and altering environmental conditions. However, much less is known about the identities or evolutionary dynamics of the symbiotic microbes that accompany invasive species. Most leguminous plants rely upon symbiotic rhizobium bacteria to fix nitrogen and are incapable of colonizing areas devoid of compatible rhizobia. We compare the genomes of symbiotic rhizobia in a portion of the legume's invaded range with those of the rhizobium symbionts from across the legume's native range. We show that in an area of California the legume Medicago polymorpha has invaded, its Ensifer medicae symbionts: (i) exhibit genome-wide patterns of relatedness that together with historical evidence support host-symbiont co-invasion from Europe into California, (ii) exhibit population genomic patterns consistent with the introduction of the majority of deep diversity from the native range, rather than a genetic bottleneck during colonization of California and (iii) harbor a large set of accessory genes uniquely enriched in binding functions, which could play a role in habitat invasion. Examining microbial symbiont genome dynamics during biological invasions is critical for assessing host-symbiont co-invasions whereby microbial symbiont range expansion underlies plant and animal invasions. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

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

KAUST Repository

Wolfowicz, Iliona

2016-09-01

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

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

KAUST Repository

Wolfowicz, Iliona; Baumgarten, Sebastian; Voss, Philipp A.; Hambleton, Elizabeth A.; Voolstra, Christian R.; Hatta, Masayuki; Guse, Annika

2016-01-01

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

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

KAUST Repository

Gao, Zhao-Ming

2014-04-01

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

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

KAUST Repository

Gao, Zhao-Ming; Wang, Yong; Tian, Ren-Mao; Wong, Yue Him; Batang, Zenon B.; Al-Suwailem, Abdulaziz M.; Bajic, Vladimir B.; Qian, Pei-Yuan

2014-01-01

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

The Cascading Development of Autonomy and Relatedness From Adolescence to Adulthood

Science.gov (United States)

Oudekerk, Barbara A.; Allen, Joseph P.; Hessel, Elenda T.; Molloy, Lauren E.

2014-01-01

We tested a developmental cascade model of autonomy and relatedness in the progression from parent to friend to romantic relationships across ages 13, 18, and 21. Participants included 184 adolescents (53% female, 58% Caucasian, 29% African American) recruited from a public middle school in Virginia. Parental psychological control at age 13 undermined the development of autonomy and relatedness, predicting relative decreases in autonomy and relatedness with friends between ages 13 and 18 and lower levels of autonomy and relatedness with partners at age 18. These cascade effects extended into adult friendships and romantic relationships, with autonomy and relatedness with romantic partners at age 18 being a strong predictor of autonomy and relatedness with both friends and partners at age 21. PMID:25345623

Symbiont dynamics during thermal acclimation using cnidarian-dinoflagellate model holobionts.

Science.gov (United States)

Núñez-Pons, Laura; Bertocci, Iacopo; Baghdasarian, Garen

2017-09-01

Warming oceans menace reef ecosystems by disrupting symbiosis between cnidarians and Symbiodinium zooxanthellae, thus triggering bleach episodes. Temperature fluctuations promote adjustments in physiological variables and symbiont composition, which can cause stress responses, but can also yield adaptation if fitter host-symbiont homeostasis are achieved. To understand such processes manipulative studies are required, but many reef-building cnidarians pose limitations to experimental prospects. We exposed Exaiptasia anemones to Gradual Thermal Stress (GTS) and Heat Shock (HS) exposures and monitored chlorophyll and symbiont dynamics to test the phenotypic plasticity of these photosynthetic holobionts. GTS enhanced chlorophyll concentrations and decreased Symbiodinium proliferation. A recovery period after GTS returned chlorophyll to lower concentrations and symbiont divisions to higher rates. HS triggered a stress response characterized by intense symbiont declines through degradation and expulsion, algal compensatory proliferation, and chlorophyll accumulation. Anemones pre-exposed to GTS displayed more acute signs of symbiont paucity after HS, demonstrating that recurrent stress does not always induce bleaching-resistance. Our study is the first documenting Symbiodinium C and D, along with the predominant Clade B1 in Exaiptasia anemones. C subclades found in outdoor specimens faded under laboratory exposures. Clade D emerged after HS treatments, and especially after GTS pre-exposure. This highlights the thermotolerance of D subclades found in E. pallida and shows that bleaching-recovery can involve shifts of background symbiont phylotypes. This study enlightens the capability of Exaiptasia anemones to acclimate to gradually increased temperatures, and explores into how thermal history influences in subsequent stress tolerance in symbiotic cnidarians. Copyright © 2017 Elsevier Ltd. All rights reserved.

On the impact of relatedness on SNP association analysis.

Science.gov (United States)

Gross, Arnd; Tönjes, Anke; Scholz, Markus

2017-12-06

When testing for SNP (single nucleotide polymorphism) associations in related individuals, observations are not independent. Simple linear regression assuming independent normally distributed residuals results in an increased type I error and the power of the test is also affected in a more complicate manner. Inflation of type I error is often successfully corrected by genomic control. However, this reduces the power of the test when relatedness is of concern. In the present paper, we derive explicit formulae to investigate how heritability and strength of relatedness contribute to variance inflation of the effect estimate of the linear model. Further, we study the consequences of variance inflation on hypothesis testing and compare the results with those of genomic control correction. We apply the developed theory to the publicly available HapMap trio data (N=129), the Sorbs (a self-contained population with N=977 characterised by a cryptic relatedness structure) and synthetic family studies with different sample sizes (ranging from N=129 to N=999) and different degrees of relatedness. We derive explicit and easily to apply approximation formulae to estimate the impact of relatedness on the variance of the effect estimate of the linear regression model. Variance inflation increases with increasing heritability. Relatedness structure also impacts the degree of variance inflation as shown for example family structures. Variance inflation is smallest for HapMap trios, followed by a synthetic family study corresponding to the trio data but with larger sample size than HapMap. Next strongest inflation is observed for the Sorbs, and finally, for a synthetic family study with a more extreme relatedness structure but with similar sample size as the Sorbs. Type I error increases rapidly with increasing inflation. However, for smaller significance levels, power increases with increasing inflation while the opposite holds for larger significance levels. When genomic control

The cascading development of autonomy and relatedness from adolescence to adulthood.

Science.gov (United States)

Oudekerk, Barbara A; Allen, Joseph P; Hessel, Elenda T; Molloy, Lauren E

2015-01-01

A developmental cascade model of autonomy and relatedness in the progression from parent to friend to romantic relationships across ages 13, 18, and 21 was examined among 184 adolescents (53% female, 58% Caucasian, 29% African American) recruited from a public middle school in Virginia. Parental psychological control at age 13 undermined the development of autonomy and relatedness, predicting relative decreases in autonomy and relatedness with friends between ages 13 and 18 and lower levels of autonomy and relatedness with partners at age 18. These cascade effects extended into adult friendships and romantic relationships, with autonomy and relatedness with romantic partners at age 18 being a strong predictor of autonomy and relatedness with both friends and partners at age 21. © 2014 The Authors. Child Development © 2014 Society for Research in Child Development, Inc.

Horizontal transfer of facultative endosymbionts is limited by host relatedness

NARCIS (Netherlands)

Lukasik, P.; Guo, H.; van Asch, M.; Henry, L.; Godfray, H.C.J.; Ferrari, J.

2015-01-01

Heritable microbial symbionts can have important effects on many aspects of their hosts' biology. Acquisition of a novel symbiont strain can provide fitness benefits to the host, with significant ecological and evolutionary consequences. We measured barriers to horizontal transmission by

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

Directory of Open Access Journals (Sweden)

K. Fujita

2011-08-01

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

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

Science.gov (United States)

2010-01-01

Background Whiteflies are cosmopolitan phloem-feeding pests that cause serious damage to many crops worldwide due to direct feeding and vectoring of many plant viruses. The sweetpotato whitefly Bemisia tabaci (Gennadius) and the greenhouse whitefly Trialeurodes vaporariorum (Westwood) are two of the most widespread and damaging whitefly species. To complete their unbalanced diet, whiteflies harbor the obligatory bacterium Portiera aleyrodidarum. B. tabaci further harbors a diverse array of secondary symbionts, including Hamiltonella, Arsenophonus, Cardinium, Wolbachia, Rickettsia and Fritschea. T. vaporariorum is only known to harbor P. aleyrodidarum and Arsenophonus. We conducted a study to survey the distribution of whitefly species in Croatia, their infection status by secondary symbionts, and the spatial distribution of these symbionts in the developmental stages of the two whitefly species. Results T. vaporariorum was found to be the predominant whitefly species across Croatia, while only the Q biotype of B. tabaci was found across the coastal part of the country. Arsenophonus and Hamiltonella were detected in collected T. vaporariorum populations, however, not all populations harbored both symbionts, and both symbionts showed 100% infection rate in some of the populations. Only the Q biotype of B. tabaci was found in the populations tested and they harbored Hamiltonella, Rickettsia, Wolbachia and Cardinium, while Arsenophonus and Fritschea were not detected in any B. tabaci populations. None of the detected symbionts appeared in all populations tested, and multiple infections were detected in some of the populations. All endosymbionts tested were localized inside the bacteriocyte in both species, but only Rickettsia and Cardinium in B. tabaci showed additional localization outside the bacteriocyte. Conclusions Our study revealed unique co-infection patterns by secondary symbionts in B. tabaci and T. vaporariorum. Co-sharing of the bacteriocyte by the primary

Effects of among-offspring relatedness on the origins and evolution of parental care and filial cannibalism.

Science.gov (United States)

Bonsall, M B; Klug, H

2011-06-01

Parental care is expected to increase the likelihood of offspring survival at the cost of investment in future reproductive success. However, alternative parental behaviours, such as filial cannibalism, can decrease current reproductive success and consequently individual fitness. We evaluate the role of among-offspring relatedness on the evolution of parental care and filial cannibalism. Building on our previous work, we show how the evolution of care is influenced by the effect of among-offspring relatedness on both the strength of competition and filial cannibalism. When there is a positive relationship between among-offspring competition and relatedness, parental care will be favoured when among-offspring relatedness is relatively low, and the maintenance of both care and no-care strategies is expected. If the relationship between among-offspring competition and relatedness is negative, parental care is most strongly favoured when broods contain highly related offspring. Further, we highlight the range of conditions over which the level of this among-offspring relatedness can affect the co-occurrence of different care/no care and cannibalism/no cannibalism strategies. Coexistence of multiple strategies is independent of the effects of among-offspring relatedness on cannibalism but more likely when among-offspring relatedness and competition are positively associated. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.

Does biological relatedness affect child survival?

Directory of Open Access Journals (Sweden)

2003-05-01

Full Text Available Objective: We studied child survival in Rakai, Uganda where many children are fostered out or orphaned. Methods: Biological relatedness is measured as the average of the Wright's coefficients between each household member and the child. Instrumental variables for fostering include proportion of adult males in household, age and gender of household head. Control variables include SES, religion, polygyny, household size, child age, child birth size, and child HIV status. Results: Presence of both parents in the household increased the odds of survival by 28%. After controlling for the endogeneity of child placement decisions in a multivariate model we found that lower biological relatedness of a child was associated with statistically significant reductions in child survival. The effects of biological relatedness on child survival tend to be stronger for both HIV- and HIV+ children of HIV+ mothers. Conclusions: Reductions in the numbers of close relatives caring for children of HIV+ mothers reduce child survival.

Juvenile corals can acquire more carbon from high-performance algal symbionts

Science.gov (United States)

Cantin, N. E.; van Oppen, M. J. H.; Willis, B. L.; Mieog, J. C.; Negri, A. P.

2009-06-01

Algal endosymbionts of the genus Symbiodinium play a key role in the nutrition of reef building corals and strongly affect the thermal tolerance and growth rate of the animal host. This study reports that 14C photosynthate incorporation into juvenile coral tissues was doubled in Acropora millepora harbouring Symbiodinium C1 compared with juveniles from common parentage harbouring Symbiodinium D in a laboratory experiment. Rapid light curves performed on the same corals revealed that the relative electron transport rate of photosystem II (rETRMAX) was 87% greater in Symbiodinium C1 than in Symbiodinium D in hospite. The greater relative electron transport through photosystem II of Symbiodinium C1 is positively correlated with increased carbon delivery to the host under the applied experimental conditions ( r 2 = 0.91). This may translate into a competitive advantage for juveniles harbouring Symbiodinium C1 under certain field conditions, since rapid early growth typically limits mortality. Both symbiont types exhibited severe reductions in 14C incorporation during a 10-h exposure to the electron transport blocking herbicide diuron (DCMU), confirming the link between electron transport through PSII and photosynthate incorporation within the host tissue. These findings advance the current understanding of symbiotic relationships between corals and their symbionts, providing evidence that enhanced growth rates of juvenile corals may result from greater translocation of photosynthates from Symbiodinium C1.

Meta-analysis reveals host-dependent nitrogen recycling as a mechanism of symbiont control in Aiptasia

KAUST Repository

Cui, Guoxin

2018-02-22

The metabolic symbiosis with photosynthetic algae of the genus Symbiodinium allows corals to thrive in the oligotrophic environments of tropical seas. Many aspects of this relationship have been investigated using transcriptomic analyses in the emerging model organism Aiptasia. However, previous studies identified thousands of putatively symbiosis-related genes, making it difficult to disentangle symbiosis-induced responses from undesired experimental parameters. Using a meta-analysis approach, we identified a core set of 731 high-confidence symbiosis-associated genes that reveal host-dependent recycling of waste ammonium and amino acid synthesis as central processes in this relationship. Combining transcriptomic and metabolomic analyses, we show that symbiont-derived carbon enables host recycling of ammonium into nonessential amino acids. We propose that this provides a regulatory mechanism to control symbiont growth through a carbon-dependent negative feedback of nitrogen availability to the symbiont. The dependence of this mechanism on symbiont-derived carbon highlights the susceptibility of this symbiosis to changes in carbon translocation, as imposed by environmental stress.

Standard methods for research on apis mellifera gut symbionts

Science.gov (United States)

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

An Approach to Measuring Semantic Relatedness of Geographic Terminologies Using a Thesaurus and Lexical Database Sources

Directory of Open Access Journals (Sweden)

Zugang Chen

2018-03-01

Full Text Available In geographic information science, semantic relatedness is important for Geographic Information Retrieval (GIR, Linked Geospatial Data, geoparsing, and geo-semantics. But computing the semantic similarity/relatedness of geographic terminology is still an urgent issue to tackle. The thesaurus is a ubiquitous and sophisticated knowledge representation tool existing in various domains. In this article, we combined the generic lexical database (WordNet or HowNet with the Thesaurus for Geographic Science and proposed a thesaurus–lexical relatedness measure (TLRM to compute the semantic relatedness of geographic terminology. This measure quantified the relationship between terminologies, interlinked the discrete term trees by using the generic lexical database, and realized the semantic relatedness computation of any two terminologies in the thesaurus. The TLRM was evaluated on a new relatedness baseline, namely, the Geo-Terminology Relatedness Dataset (GTRD which was built by us, and the TLRM obtained a relatively high cognitive plausibility. Finally, we applied the TLRM on a geospatial data sharing portal to support data retrieval. The application results of the 30 most frequently used queries of the portal demonstrated that using TLRM could improve the recall of geospatial data retrieval in most situations and rank the retrieval results by the matching scores between the query of users and the geospatial dataset.

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

Science.gov (United States)

Borges, Renee M

2017-07-01

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

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

Science.gov (United States)

2018-01-01

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

Accumulation of radionuclides by lichen symbionts

Energy Technology Data Exchange (ETDEWEB)

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

1983-01-01

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

Is prospective memory enhanced by cue-action semantic relatedness and enactment at encoding?

Science.gov (United States)

Pereira, Antonina; Ellis, Judi; Freeman, Jayne

2012-09-01

Benefits and costs on prospective memory performance, of enactment at encoding and a semantic association between a cue-action word pair, were investigated in two experiments. Findings revealed superior performance for both younger and older adults following enactment, in contrast to verbal encoding, and when cue-action semantic relatedness was high. Although younger adults outperformed older adults, age did not moderate benefits of cue-action relatedness or enactment. Findings from a second experiment revealed that the inclusion of an instruction to perform a prospective memory task led to increments in response latency to items from the ongoing activity in which that task was embedded, relative to latencies when the ongoing task only was performed. However, this task interference 'cost' did not differ as a function of either cue-action relatedness or enactment. We argue that the high number of cue-action pairs employed here influenced meta-cognitive consciousness, hence determining attention allocation, in all experimental conditions. Copyright © 2012 Elsevier Inc. All rights reserved.

Italian Adaptation of the "Autonomy and Relatedness Coding System"

Directory of Open Access Journals (Sweden)

Sonia Ingoglia

2013-08-01

Full Text Available The study examined the applicability of the observational technique developed by Allen and colleagues (Allen, Hauser, Bell, & O’Connor, 1994; Allen, Hauser, et al., 2003 to investigate the issues of autonomy and relatedness in parent-adolescent relationship in the Italian context. Thirty-five mother-adolescent dyads participated to a task in which they discussed a family issue about which they disagree. Adolescents were also administered a self-report measure assessing their relationship with mothers. Mothers reported significantly higher levels of promoting and inhibiting autonomy, and promoting relatedness behaviors than their children. Results also suggested a partial behavioral reciprocity within the dyads, regarding promoting and inhibiting relatedness, and inhibiting autonomy. Finally, mothers’ inhibiting autonomy behaviors positively correlated to teens’ perception of their relationship as conflicting; adolescents’ inhibiting and promoting autonomy and inhibiting relatedness behaviors positively correlated to open confrontation, rejection and coolness, while promoting relatedness behaviors negatively correlated to open confrontation, rejection and coolness. The results suggest that, for Italian mothers, behaviors linked to autonomy seem to be associated with being involved in a more negative relationship with their children, even if not characterized by open hostility, while for Italian adolescents, behaviors linked to autonomy seem to be associated with threatening the closeness of the relationship. Globally, the findings suggest that the application of this observational procedure may help our understanding of youth autonomy and relatedness development in Italy, but they leave unanswered questions regarding its appropriate adaptation and the role played by cultural differences.

The facilitation effect of associative and semantic relatedness in word recognition

Directory of Open Access Journals (Sweden)

Jakić Milena

2011-01-01

Full Text Available In this study we addressed three issues concerning semantic and associative relatedness between two words and how they prime each other. The first issue is whether there is a priming effect of semantic relatedness over and above the effect of associative relatedness. The second issue is how difference in semantic overlap between two words affects priming. In order to specify the semantic overlap we introduce five relation types that differ in number of common semantic components. Three relation types (synonyms, antonyms and hyponyms represent semantic relatedness while two relation types represent associative relatedness, with negligible or no semantic relatedness. Finally, the third issue addressed in this study is whether there is a symmetric priming effect if we swap the position of prime and target, i.e. whether the direction of relatedness between two words affects priming. In two lexical decision experiments we presented five types of word pairs. In both experiments we obtained stronger facilitation for pairs that were both semantically and associatively related. Closer inspection showed that larger semantic overlap between words is paralleled by greater facilitation effect. The effects did not change when prime and target swap their position, indicating that the observed facilitation effects are symmetrical. This outcome complies with predictions of distributed models of memory.

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

Directory of Open Access Journals (Sweden)

Jennifer L Kovacs

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

Relatedness and social organization of coypus in the Argentinean pampas

Science.gov (United States)

Tunez, J.I.; Guichon, M.L.; Centron, D.; Henderson, A.P.; Callahan, C.; Cassini, M.H.

2009-01-01

Behavioural and trapping studies of the social organization of coypus have suggested the occurrence of kin groups and a polygynous mating system. We used 16 microsatellite markers to analyse parentage and relatedness relationships in two populations (J??uregui and Villa Ruiz) in the Argentinean Pampas. At J??uregui, a dominant male monopolized most paternities, leading to a high variance in reproductive success between males and a high level of polygyny. At Villa Ruiz, variance in reproductive success was low among resident males and males were the fathers of zero to four offspring each. For females, no significant differences were found. Two different social groups in each study site were used to assess genetic relatedness within and between groups. These groups were neighbouring at J??uregui but not at Villa Ruiz. At Villa Ruiz, coypus were significantly more related within than between groups, suggesting that behavioural groups were also genetic ones, and adult females were more related within than between groups, as should be expected for kin groups. This relationship was not found at J??uregui. Our results provide support to previous studies based on behavioural and trapping data, which indicate that coypus form social groups and have a polygynous mating system. However, we found differences in social organization between the two populations. This is the first study to determine parentage and/or relatedness in coypus. ?? 2008 The Authors.

Change in algal symbiont communities after bleaching, not prior heat exposure, increases heat tolerance of reef corals.

Science.gov (United States)

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

2015-01-01

Mutualistic organisms can be particularly susceptible to climate change stress, as their survivorship is often limited by the most vulnerable partner. However, symbiotic plasticity can also help organisms in changing environments by expanding their realized niche space. Coral-algal (Symbiodinium spp.) symbiosis exemplifies this dichotomy: the partnership is highly susceptible to 'bleaching' (stress-induced symbiosis breakdown), but stress-tolerant symbionts can also sometimes mitigate bleaching. Here, we investigate the role of diverse and mutable symbiotic partnerships in increasing corals' ability to thrive in high temperature conditions. We conducted repeat bleaching and recovery experiments on the coral Montastraea cavernosa, and used quantitative PCR and chlorophyll fluorometry to assess the structure and function of Symbiodinium communities within coral hosts. During an initial heat exposure (32 °C for 10 days), corals hosting only stress-sensitive symbionts (Symbiodinium C3) bleached, but recovered (at either 24 °C or 29 °C) with predominantly (>90%) stress-tolerant symbionts (Symbiodinium D1a), which were not detected before bleaching (either due to absence or extreme low abundance). When a second heat stress (also 32 °C for 10 days) was applied 3 months later, corals that previously bleached and were now dominated by D1a Symbiodinium experienced less photodamage and symbiont loss compared to control corals that had not been previously bleached, and were therefore still dominated by Symbiodinium C3. Additional corals that were initially bleached without heat by a herbicide (DCMU, at 24 °C) also recovered predominantly with D1a symbionts, and similarly lost fewer symbionts during subsequent thermal stress. Increased thermotolerance was also not observed in C3-dominated corals that were acclimated for 3 months to warmer temperatures (29 °C) before heat stress. These findings indicate that increased thermotolerance post-bleaching resulted from

Specific Midgut Region Controlling the Symbiont Population in an Insect-Microbe Gut Symbiotic Association

Science.gov (United States)

Kim, Jiyeun Kate; Kim, Na Hyang; Jang, Ho Am; Kikuchi, Yoshitomo; Kim, Chan-Hee

2013-01-01

Many insects possess symbiotic bacteria that affect the biology of the host. The level of the symbiont population in the host is a pivotal factor that modulates the biological outcome of the symbiotic association. Hence, the symbiont population should be maintained at a proper level by the host's control mechanisms. Several mechanisms for controlling intracellular symbionts of insects have been reported, while mechanisms for controlling extracellular gut symbionts of insects are poorly understood. The bean bug Riptortus pedestris harbors a betaproteobacterial extracellular symbiont of the genus Burkholderia in the midgut symbiotic organ designated the M4 region. We found that the M4B region, which is directly connected to the M4 region, also harbors Burkholderia symbiont cells, but the symbionts therein are mostly dead. A series of experiments demonstrated that the M4B region exhibits antimicrobial activity, and the antimicrobial activity is specifically potent against the Burkholderia symbiont but not the cultured Burkholderia and other bacteria. The antimicrobial activity of the M4B region was detected in symbiotic host insects, reaching its highest point at the fifth instar, but not in aposymbiotic host insects, which suggests the possibility of symbiont-mediated induction of the antimicrobial activity. This antimicrobial activity was not associated with upregulation of antimicrobial peptides of the host. Based on these results, we propose that the M4B region is a specialized gut region of R. pedestris that plays a critical role in controlling the population of the Burkholderia gut symbiont. The molecular basis of the antimicrobial activity is of great interest and deserves future study. PMID:24038695

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

Science.gov (United States)

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

2013-08-01

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

Psychological autonomy and hierarchical relatedness as organizers of developmental pathways

OpenAIRE

Keller, Heidi

2016-01-01

The definition of self and others can be regarded as embodying the two dimensions of autonomy and relatedness. Autonomy and relatedness are two basic human needs and cultural constructs at the same time. This implies that they may be differently defined yet remain equally important. The respective understanding of autonomy and relatedness is socialized during the everyday experiences of daily life routines from birth on. In this paper, two developmental pathways are portrayed that emphasize d...

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

KAUST Repository

Chen, Jit Ern; Cui, Guoxin; Wang, Xin; Liew, Yi Jin; Aranda, Manuel

2017-01-01

Rising sea surface temperature is the main cause of global coral reef decline. Abnormally high temperatures trigger the breakdown of the symbiotic association between corals and their photosynthetic symbionts in the genus Symbiodinium. Higher

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

Science.gov (United States)

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

2017-09-26

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

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

DEFF Research Database (Denmark)

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

2009-01-01

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

Unraveling the role of fungal symbionts in plant abiotic stress tolerance

Science.gov (United States)

Singh, Lamabam Peter

2011-01-01

Fungal symbionts have been found to be associated with every plant studied in the natural ecosystem, where they colonize and reside entirely or partially in the internal tissues of their host plant. Fungal endophytes can express/form a range of different lifestyle/relationships with different host including symbiotic, mutualistic, commensalistic and parasitic in response to host genotype and environmental factors. In mutualistic association fungal endophyte can enhance growth, increase reproductive success and confer biotic and abiotic stress tolerance to its host plant. Since abiotic stress such as, drought, high soil salinity, heat, cold, oxidative stress and heavy metal toxicity is the common adverse environmental conditions that affect and limit crop productivity worldwide. It may be a promising alternative strategy to exploit fungal endophytes to overcome the limitations to crop production brought by abiotic stress. There is an increasing interest in developing the potential biotechnological applications of fungal endophytes for improving plant stress tolerance and sustainable production of food crops. Here we have described the fungal symbioses, fungal symbionts and their role in abiotic stress tolerance. A putative mechanism of stress tolerance by symbionts has also been covered. PMID:21512319

Evolution: Welcome to Symbiont Prison

NARCIS (Netherlands)

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

2016-01-01

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

Insect symbionts in food webs

Czech Academy of Sciences Publication Activity Database

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

2016-01-01

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

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

Science.gov (United States)

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

2018-03-01

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

Preferences of newborn mice for odours indicating closer genetic relatedness: is experience necessary?

Science.gov (United States)

Todrank, Josephine; Busquet, Nicolas; Baudoin, Claude; Heth, Giora

2005-10-07

Evidence from studies with adult rodents indicates that individual recognition enables distinctions between familiar individuals irrespective of relatedness (but including close kin) and a separate mechanism enables discriminations based on genetic relatedness without prior familiarity. For example, adult mice could assess the extent of their genetic relatedness to unfamiliar individuals using perceptual similarities between their individual odours. The ontogeny of this genetic relatedness assessment mechanism, however, had not been investigated. Here, in two-choice tests, newborn mice differentially preferred odours of more genetically similar lactating females (paternal aunts to unrelated conspecific and conspecific to heterospecific) even without prior direct exposure to adults with the tested genotypes. The results provide a direct demonstration of genetic relatedness assessment abilities in newborns and show that experience with parental odours is not necessary for genetic relatedness distinctions. Future studies will be necessary to determine whether exposure to odours of other foetuses in the womb or littermates shortly after birth affects this genetic relatedness assessment process.

Farming termites determine the genetic population structure of Termitomyces fungal symbionts

DEFF Research Database (Denmark)

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

2011-01-01

Symbiotic interactions between macrotermitine termites and their fungal symbionts have a moderate degree of specificity. Consistent with horizontal symbiont transmission, host switching has been frequent over evolutionary time so that single termite species can often be associated with several fu...

Genetic relatedness of low solitary nests of Apis dorsata from Marang, Terengganu, Malaysia.

Directory of Open Access Journals (Sweden)

Najmeh Sahebzadeh

Full Text Available Knowledge on the population of genetic structure and ecological behaviour of Apis dorsata from Peninsular Malaysia is needed for effective management and conservation of this species since unsustainable whole solitary low nest cutting for product harvesting is the current common practice here. The analysis of 15 single locus DNA microsatellite markers on samples from 20 solitary nests of A. dorsata showed that while these markers were polymorphic, high intracolonial relatedness existed. Furthermore, in general, slightly negative values of intercolony relatedness (R among the nests of A. dorsata were found. However, positive values of mean intercolony relatedness were observed between 54 pairs of nests out of 190 possible combinations. The R values among nest pairs 3-4 and 3-5 was higher than 0.50 showing that their queens were half siblings, whereas nest pair 19-20 showed relatedness of 0.95 indicating that the same queen was sampled. The results that we obtained could not conclusively support the hypothesis of this study that the honey hunters in Marang district of Malaysia repeatedly harvest the same nest located at a different site and at a different time during the same honey harvesting season. However, our finding of an appreciable level of intercolonial relatedness between several pairs of nests in this pioneer study indicated that a comprehensive study with a larger sample size of solitary nests found throughout the region would be necessary to provide concrete proof for this novel idea.

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

NARCIS (Netherlands)

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

2007-01-01

1. Fungus-growing termites live in an obligate mutualistic symbiosis with Termitomyces fungi. The functions of the fungal symbiont have been hypothesised to differ between species and to range from highly specific roles of providing plant-degrading enzymes complementary to termite gut enzymes, to

Burkholderia Species Are the Most Common and Preferred Nodulating Symbionts of the Piptadenia Group (Tribe Mimoseae)

Science.gov (United States)

Bournaud, Caroline; de Faria, Sergio Miana; dos Santos, José Miguel Ferreira; Tisseyre, Pierre; Silva, Michele; Chaintreuil, Clémence; Gross, Eduardo; James, Euan K.; Prin, Yves; Moulin, Lionel

2013-01-01

Burkholderia legume symbionts (also called α-rhizobia) are ancient in origin and are the main nitrogen-fixing symbionts of species belonging to the large genus Mimosa in Brazil. We investigated the extent of the affinity between Burkholderia and species in the tribe Mimoseae by studying symbionts of the genera Piptadenia (P.), Parapiptadenia (Pp.), Pseudopiptadenia (Ps.), Pityrocarpa (Py.), Anadenanthera (A.) and Microlobius (Mi.), all of which are native to Brazil and are phylogenetically close to Mimosa, and which together with Mimosa comprise the “Piptadenia group”. We characterized 196 strains sampled from 18 species from 17 locations in Brazil using two neutral markers and two symbiotic genes in order to assess their species affiliations and the evolution of their symbiosis genes. We found that Burkholderia are common and highly diversified symbionts of species in the Piptadenia group, comprising nine Burkholderia species, of which three are new ones and one was never reported as symbiotic (B. phenoliruptrix). However, α-rhizobia were also detected and were occasionally dominant on a few species. A strong sampling site effect on the rhizobial nature of symbionts was detected, with the symbiont pattern of the same legume species changing drastically from location to location, even switching from β to α-rhizobia. Coinoculation assays showed a strong affinity of all the Piptadenia group species towards Burkholderia genotypes, with the exception of Mi. foetidus. Phylogenetic analyses of neutral and symbiotic markers showed that symbiosis genes in Burkholderia from the Piptadenia group have evolved mainly through vertical transfer, but also by horizontal transfer in two species. PMID:23691052

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

Directory of Open Access Journals (Sweden)

Elad Chiel

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

Psychological autonomy and hierarchical relatedness as organizers of developmental pathways.

Science.gov (United States)

Keller, Heidi

2016-01-19

The definition of self and others can be regarded as embodying the two dimensions of autonomy and relatedness. Autonomy and relatedness are two basic human needs and cultural constructs at the same time. This implies that they may be differently defined yet remain equally important. The respective understanding of autonomy and relatedness is socialized during the everyday experiences of daily life routines from birth on. In this paper, two developmental pathways are portrayed that emphasize different conceptions of autonomy and relatedness that are adaptive in two different environmental contexts with very different affordances and constraints. Western middle-class children are socialized towards psychological autonomy, i.e. the primacy of own intentions, wishes, individual preferences and emotions affording a definition of relatedness as psychological negotiable construct. Non-Western subsistence farmer children are socialized towards hierarchical relatedness, i.e. positioning oneself into the hierarchical structure of a communal system affording a definition of autonomy as action oriented, based on responsibility and obligations. Infancy can be regarded as a cultural lens through which to study the different socialization agendas. Parenting strategies that aim at supporting these different socialization goals in German and Euro-American parents on the one hand and Nso farmers from North Western Cameroon on the other hand are described. It is concluded that different pathways need to be considered in order to understand human psychology from a global perspective. © 2015 The Author(s).

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

NARCIS (Netherlands)

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

2006-01-01

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

Insights into deep-sea adaptations and host-symbiont interactions: A comparative transcriptome study on Bathymodiolus mussels and their coastal relatives.

Science.gov (United States)

Zheng, Ping; Wang, Minxiao; Li, Chaolun; Sun, Xiaoqing; Wang, Xiaocheng; Sun, Yan; Sun, Song

2017-10-01

Mussels (Bivalve: Mytilidae) have adapted to various habitats, from fresh water to the deep sea. To understand their adaptive characteristics in different habitats, particularly in the bathymodiolin mussels in deep-sea chemosynthetic ecosystems, we conducted a comparative transcriptomic analysis between deep-sea bathymodiolin mussels and their shallow-water relatives. A number of gene families related to stress responses were shared across all mussels, without specific or significantly expanded families in deep-sea species, indicating that all mussels are capable of adapting to diverse harsh environments, but that different members of the same gene family may be preferentially utilized by different species. One of the most extraordinary trait of bathymodiolin mussels is their endosymbiosis. Lineage-specific and positively selected TLRs and highly expressed C1QDC proteins were identified in the gills of the bathymodiolins, suggesting their possible functions in symbiont recognition. However, pattern recognition receptors of the bathymodiolins were globally reduced, facilitating the invasion and maintenance of the symbionts obtained by either endocytosis or phagocytosis. Additionally, various transporters were positively selected or more highly expressed in the deep-sea mussels, indicating a means by which necessary materials could be provided for the symbionts. Key genes supporting lysosomal activity were also positively selected or more highly expressed in the deep-sea mussels, suggesting that nutrition fixed by the symbionts can be absorbed in a "farming" way wherein the symbionts are digested by lysosomes. Regulation of key physiological processes including lysosome activity, apoptosis and immune reactions is needed to maintain a stable host-symbiont relationship, but the mechanisms are still unclear. © 2017 The Authors. Molecular Ecology Published by John Wiley & Sons Ltd.

Surfing the vegetal pole in a small population: extracellular vertical transmission of an 'intracellular' deep-sea clam symbiont.

Science.gov (United States)

Ikuta, Tetsuro; Igawa, Kanae; Tame, Akihiro; Kuroiwa, Tsuneyoshi; Kuroiwa, Haruko; Aoki, Yui; Takaki, Yoshihiro; Nagai, Yukiko; Ozawa, Genki; Yamamoto, Masahiro; Deguchi, Ryusaku; Fujikura, Katsunori; Maruyama, Tadashi; Yoshida, Takao

2016-05-01

Symbiont transmission is a key event for understanding the processes underlying symbiotic associations and their evolution. However, our understanding of the mechanisms of symbiont transmission remains still fragmentary. The deep-sea clam Calyptogena okutanii harbours obligate sulfur-oxidizing intracellular symbiotic bacteria in the gill epithelial cells. In this study, we determined the localization of their symbiont associating with the spawned eggs, and the population size of the symbiont transmitted via the eggs. We show that the symbionts are located on the outer surface of the egg plasma membrane at the vegetal pole, and that each egg carries approximately 400 symbiont cells, each of which contains close to 10 genomic copies. The very small population size of the symbiont transmitted via the eggs might narrow the bottleneck and increase genetic drift, while polyploidy and its transient extracellular lifestyle might slow the rate of genome reduction. Additionally, the extracellular localization of the symbiont on the egg surface may increase the chance of symbiont exchange. This new type of extracellular transovarial transmission provides insights into complex interactions between the host and symbiont, development of both host and symbiont, as well as the population dynamics underlying genetic drift and genome evolution in microorganisms.

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

Directory of Open Access Journals (Sweden)

Roo Vandegrift

2015-11-01

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

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

Directory of Open Access Journals (Sweden)

Bin Hirota

2017-09-01

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

Host-Polarized Cell Growth in Animal Symbionts.

Science.gov (United States)

Pende, Nika; Wang, Jinglan; Weber, Philipp M; Verheul, Jolanda; Kuru, Erkin; Rittmann, Simon K-M R; Leisch, Nikolaus; VanNieuwenhze, Michael S; Brun, Yves V; den Blaauwen, Tanneke; Bulgheresi, Silvia

2018-04-02

To determine the fundamentals of cell growth, we must extend cell biological studies to non-model organisms. Here, we investigated the growth modes of the only two rods known to widen instead of elongating, Candidatus Thiosymbion oneisti and Thiosymbion hypermnestrae. These bacteria are attached by one pole to the surface of their respective nematode hosts. By incubating live Ca. T. oneisti and T. hypermnestrae with a peptidoglycan metabolic probe, we observed that the insertion of new cell wall starts at the poles and proceeds inward, concomitantly with FtsZ-based membrane constriction. Remarkably, in Ca. T. hypermnestrae, the proximal, animal-attached pole grows before the distal, free pole, indicating that the peptidoglycan synthesis machinery is host oriented. Immunostaining of the symbionts with an antibody against the actin homolog MreB revealed that it was arranged medially-that is, parallel to the cell long axis-throughout the symbiont life cycle. Given that depolymerization of MreB abolished newly synthesized peptidoglycan insertion and impaired divisome assembly, we conclude that MreB function is required for symbiont widening and division. In conclusion, our data invoke a reassessment of the localization and function of the bacterial actin homolog. Copyright © 2018 The Author(s). Published by Elsevier Ltd.. All rights reserved.

Fiber, food, fuel, and fungal symbionts.

Science.gov (United States)

Ruehle, J L; Marx, D H

1979-10-26

Virtually all plants of economic importance form mycorrhizae. These absorbing organs of higher plants result from a symbiotic union of beneficial soil fungi and feeder roots. In forestry, the manipulation of fungal symbionts ecologically adapted to the planting site can increase survival and growth of forest trees, particularly on adverse sites. Vesicular-arbuscular mycorrhizae, which occur not only on many trees but also on most cultivated crops, are undoubtedly more important to world food crops. Imperatives for mycorrhizal research in forestry and agriculture are (i) the development of mass inoculum of mycorrhizal fungi, (ii) the interdisciplinary coordination with soil management, plant breeding, cultivation practices, and pest control to ensure maximum survival and development of fungal symbionts in the soil, and (iii) the institution of nursery and field tests to determine the circumstances in which mycorrhizae benefit plant growth in forestry and agri-ecosystems.

Metagenomic Analysis of Microbial Symbionts in a Gutless Worm

Energy Technology Data Exchange (ETDEWEB)

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

2006-05-01

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

Autonomy and Relatedness in Inner-City Families of Substance Abusing Adolescents.

Science.gov (United States)

Samuolis, Jessica; Hogue, Aaron; Dauber, Sarah; Liddle, Howard A

2006-01-01

This study examined parent-adolescent autonomous-relatedness functioning in inner-city, ethnic minority families of adolescents exhibiting drug abuse and related problem behaviors. Seventy-four parent-adolescent dyads completed a structured interaction task prior to the start of treatment that was coded using an established autonomous-relatedness measure. Adolescent drug use, externalizing, and internalizing behaviors were assessed. Parents and adolescents completed assessment instruments measuring parenting style and family conflict. Confirmatory factor analysis found significant differences in the underlying dimensions of parent and adolescent autonomous-relatedness in this sample versus previous samples. It was also found that autonomous-relatedness was associated with worse adolescent symptomatology and family impairment. Results based on both self-report and observational measures contribute to the understanding of key family constructs in this population and provide insight for both researchers and the treatment community.

Could relatedness help explain why individuals lead in bottlenose dolphin groups?

Science.gov (United States)

Lewis, Jennifer S; Wartzok, Douglas; Heithaus, Michael; Krützen, Michael

2013-01-01

In many species, particular individuals consistently lead group travel. While benefits to followers often are relatively obvious, including access to resources, benefits to leaders are often less obvious. This is especially true for species that feed on patchy mobile resources where all group members may locate prey simultaneously and food intake likely decreases with increasing group size. Leaders in highly complex habitats, however, could provide access to foraging resources for less informed relatives, thereby gaining indirect benefits by helping kin. Recently, leadership has been documented in a population of bottlenose dolphins (Tursiops truncatus) where direct benefits to leaders appear unlikely. To test whether leaders could benefit indirectly we examined relatedness between leader-follower pairs and compared these levels to pairs who associated but did not have leader-follower relationship (neither ever led the other). We found the average relatedness value for leader-follower pairs was greater than expected based on chance. The same was not found when examining non leader-follower pairs. Additionally, relatedness for leader-follower pairs was positively correlated with association index values, but no correlation was found for this measure in non leader-follower pairs. Interestingly, haplotypes were not frequently shared between leader-follower pairs (25%). Together, these results suggest that bottlenose dolphin leaders have the opportunity to gain indirect benefits by leading relatives. These findings provide a potential mechanism for the maintenance of leadership in a highly dynamic fission-fusion population with few obvious direct benefits to leaders.

Could relatedness help explain why individuals lead in bottlenose dolphin groups?

Directory of Open Access Journals (Sweden)

Jennifer S Lewis

Full Text Available In many species, particular individuals consistently lead group travel. While benefits to followers often are relatively obvious, including access to resources, benefits to leaders are often less obvious. This is especially true for species that feed on patchy mobile resources where all group members may locate prey simultaneously and food intake likely decreases with increasing group size. Leaders in highly complex habitats, however, could provide access to foraging resources for less informed relatives, thereby gaining indirect benefits by helping kin. Recently, leadership has been documented in a population of bottlenose dolphins (Tursiops truncatus where direct benefits to leaders appear unlikely. To test whether leaders could benefit indirectly we examined relatedness between leader-follower pairs and compared these levels to pairs who associated but did not have leader-follower relationship (neither ever led the other. We found the average relatedness value for leader-follower pairs was greater than expected based on chance. The same was not found when examining non leader-follower pairs. Additionally, relatedness for leader-follower pairs was positively correlated with association index values, but no correlation was found for this measure in non leader-follower pairs. Interestingly, haplotypes were not frequently shared between leader-follower pairs (25%. Together, these results suggest that bottlenose dolphin leaders have the opportunity to gain indirect benefits by leading relatives. These findings provide a potential mechanism for the maintenance of leadership in a highly dynamic fission-fusion population with few obvious direct benefits to leaders.

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

Directory of Open Access Journals (Sweden)

Susanna López-Legentil

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

Live imaging of symbiosis: spatiotemporal infection dynamics of a GFP-labelled Burkholderia symbiont in the bean bug Riptortus pedestris

Science.gov (United States)

Kikuchi, Yoshitomo; Fukatsu, Takema

2014-01-01

Many insects possess endosymbiotic bacteria inside their body, wherein intimate interactions occur between the partners. While recent technological advancements have deepened our understanding of metabolic and evolutionary features of the symbiont genomes, molecular mechanisms underpinning the intimate interactions remain difficult to approach because the insect symbionts are generally uncultivable. The bean bug Riptortus pedestris is associated with the betaproteobacterial Burkholderia symbiont in a posterior region of the midgut, which develops numerous crypts harbouring the symbiont extracellularly. Distinct from other insect symbiotic systems, R. pedestris acquires the Burkholderia symbiont not by vertical transmission but from the environment every generation. By making use of the cultivability and the genetic tractability of the symbiont, we constructed a transgenic Burkholderia strain labelled with green fluorescent protein (GFP), which enabled detailed observation of spatiotemporal dynamics and the colonization process of the symbiont in freshly prepared specimens. The symbiont live imaging revealed that, at the second instar, colonization of the symbiotic midgut M4 region started around 6 h after inoculation (hai). By 24 hai, the symbiont cells appeared in the main tract and also in several crypts of the M4. By 48 hai, most of the crypts were colonized by the symbiont cells. By 72 hai, all the crypts were filled up with the symbiont cells and the symbiont localization pattern continued during the subsequent nymphal development. Quantitative PCR of the symbiont confirmed the infection dynamics quantitatively. These results highlight the stinkbug-Burkholderia gut symbiosis as an unprecedented model for comprehensive understanding of molecular mechanisms underpinning insect symbiosis. PMID:24103110

Relationship of the luminous bacterial symbiont of the Caribbean flashlight fish, Kryptophanaron alfredi (family Anomalopidae) to other luminous bacteria based on bacterial luciferase (luxA) genes.

Science.gov (United States)

Haygood, M G

1990-01-01

Flashlight fishes (family Anomalopidae) have light organs that contain luminous bacterial symbionts. Although the symbionts have not yet been successfully cultured, the luciferase genes have been cloned directly from the light organ of the Caribbean species, Kryptophanaron alfredi. The goal of this project was to evaluate the relationship of the symbiont to free-living luminous bacteria by comparison of genes coding for bacterial luciferase (lux genes). Hybridization of a lux AB probe from the Kryptophanaron alfredi symbiont to DNAs from 9 strains (8 species) of luminous bacteria showed that none of the strains tested had lux genes highly similar to the symbiont. The most similar were a group consisting of Vibrio harveyi, Vibrio splendidus and Vibrio orientalis. The nucleotide sequence of the luciferase alpha subunit gene luxA) of the Kryptophanaron alfredi symbiont was determined in order to do a more detailed comparison with published luxA sequences from Vibrio harveyi, Vibrio fischeri and Photobacterium leiognathi. The hybridization results, sequence comparisons and the mol% G + C of the Kryptophanaron alfredi symbiont luxA gene suggest that the symbiont may be considered as a new species of luminous Vibrio related to Vibrio harveyi.

Diversity and Phylogenetic Analyses of Bacterial Symbionts in Three Whitefly Species from Southeast Europe

OpenAIRE

Skaljac, Marisa; Kanakala, Surapathrudu; Zanic, Katja; Puizina, Jasna; Lepen Pleic, Ivana; Ghanim, Murad

2017-01-01

Bemisia tabaci (Gennadius), Trialeurodes vaporariorum (Westwood), and Siphoninus phillyreae (Haliday) are whitefly species that harm agricultural crops in many regions of the world. These insects live in close association with bacterial symbionts that affect host fitness and adaptation to the environment. In the current study, we surveyed the infection of whitefly populations in Southeast Europe by various bacterial symbionts and performed phylogenetic analyses on the different symbionts dete...

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

Directory of Open Access Journals (Sweden)

Tong Li

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

Mechanisms of symbiont-conferred protection against natural enemies: an ecological and evolutionary framework.

Science.gov (United States)

Gerardo, Nicole M; Parker, Benjamin J

2014-10-01

Many vertically-transmitted microbial symbionts protect their insect hosts from natural enemies, including host-targeted pathogens and parasites, and those vectored by insects to other hosts. Protection is often achieved through production of inhibiting toxins, which is not surprising given that toxin production mediates competition in many environments. Classical models of macroecological interactions, however, demonstrate that interspecific competition can be less direct, and recent research indicates that symbiont-protection can be mediated through exploitation of limiting resources, and through activation of host immune mechanisms that then suppress natural enemies. Available data, though limited, suggest that effects of symbionts on vectored pathogens and parasites, as compared to those that are host-targeted, are more likely to result from symbiont activation of the host immune system. We discuss these different mechanisms in light of their potential impact on the evolution of host physiological processes. Copyright © 2014 Elsevier Inc. All rights reserved.

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

Science.gov (United States)

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

2014-07-01

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

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

Science.gov (United States)

Susoy, V; Herrmann, M

2014-05-01

Host-symbiont systems are of particular interest to evolutionary biology because they allow testable inferences of diversification processes while also providing both a historical basis and an ecological context for studies of adaptation. Our investigations of bark beetle symbionts, predatory nematodes of the genus Micoletzkya, have revealed remarkable diversity of the group along with a high level of host specificity. Cophylogenetic analyses suggest that evolution of the nematodes was largely influenced by the evolutionary history of beetles. The diversification of the symbionts, however, could not be attributed to parallel divergence alone; our results indicate that adaptive radiation of the nematodes was shaped by preferential host shifts among closely related beetles along with codivergence. Whereas ecological and geographic isolation have played a major role in the diversification of Micoletzkya at shallow phylogenetic depths, adaptations towards related hosts have played a role in shaping cophylogenetic structure at a larger evolutionary scale. © 2014 The Authors. Journal of Evolutionary Biology © 2014 European Society For Evolutionary Biology.

Host tolerance, not symbiont tolerance, determines the distribution of coral species in relation to their environment at a Central Pacific atoll

Science.gov (United States)

Wicks, L. C.; Gardner, J. P. A.; Davy, S. K.

2012-06-01

Tolerance of environmental variables differs between corals and their dinoflagellate symbionts ( Symbiodinium spp.), controlling the holobiont's (host and symbiont combined) resilience to environmental stress. However, the ecological role that environmental variables play in holobiont distribution remains poorly understood. We compared the drivers of symbiont and coral species distributions at Palmyra Atoll, a location with a range of reef environments from low to high sediment concentrations (1-52 g dry weight m-2 day-1). We observed uniform holobiont partnerships across the atoll (e.g. Montipora spp. with Symbiodinium type C15 at all sites). Multivariate analysis revealed that field-based estimates of settling sediment predominantly explained the spatial variation of coral species among sites ( P coral rather than Symbiodinium physiology. The data highlight the importance of host tolerance to environmental stressors, which should be considered simultaneously with symbiont sensitivity when considering the impact of variations in environmental conditions on coral communities.

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

Science.gov (United States)

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

2013-12-01

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

Student Perceptions and Motivation in the Classroom: Exploring Relatedness and Value

Science.gov (United States)

Kaufman, Annette; Dodge, Tonya

2009-01-01

According to Self-Determination Theory, feelings of relatedness and value of a behavior are critical factors that affect internalization and integration. The purpose of the current study was to identify factors that influence relatedness and value in an academic setting. Specifically, the study investigated the effects of autonomy, mastery goals,…

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

NARCIS (Netherlands)

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

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

PENGELOLAAN KNOWLEDGE MANAGEMENT CAPABILITY DALAM MEMEDIASI DUKUNGAN INFORMATION TECHNOLOGY RELATEDNESS TERHADAP KINERJA PERUSAHAAN

Directory of Open Access Journals (Sweden)

Luluk Muhimatul Ifada

2011-06-01

Full Text Available The study examines whether or not and how information technology (IT relatedness influences corporate performance. This study proposes that knowledge management (KM is a critical organizational capability through which IT influences firm performance. Measurement of IT relatedness and KM capability uses a reflective second-order factor modeling approach for capturing complementarities among the four dimensions of IT relatedness (IT strategy making processes, IT vendor management processes, IT human resource management processes and IT infrastructure and for capturing complementarities among the three dimensions of KM capability (product KM capability, customer KM capability, and managerial KM capability. A survey was conducted among 93 branch managers of banking in Central Java. Structural Equation Model (SEM was used to analyze the data using the software program of SmartPLS (Partial Least Square. The findings support for the hypotheses of the study. IT relatedness of business units enhances the cross unit KM capability of the corporate. The KM capability creates and exploits cross-unit synergies from the product, customer, and managerial knowledge resources of the corporate. These synergies increase the corporate performance. IT relatedness of business units positively influences corporate performance. IT relatedness also has significant indirect effects on corporate performance through the mediation of KM capability.

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

DEFF Research Database (Denmark)

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

2006-01-01

the extracted DNA. The presence of the symbionts in the ampulla was verified by performing fluorescence in situ hybridization (FISH) on all worm species using an Acidovorax-specific probe. Earthworm and symbiont phylogeny was largely congruent, indicating that host and symbiont have indeed co-evolved since...... the initial bacterial colonization of an ancestral lumbricid worm. However, the association is complicated by the recent discovery of additional, putative symbiotic bacteria which have been detected in the ampulla of several earthworms by FISH. Identity, distribution among earthworms, and function...... within the genus Acidovorax [2], and they are transmitted vertically [3]. For these reasons, we suggest that the earthworm-Acidovorax association has evolved by co-speciation. This hypothesis was tested by a comparative study of earthworm and symbiont phylogeny. Different earthworm species were collected...

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

KAUST Repository

Ziegler, Maren

2017-12-01

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

Identity recognition in response to different levels of genetic relatedness in commercial soya bean

Science.gov (United States)

Van Acker, Rene; Rajcan, Istvan; Swanton, Clarence J.

2017-01-01

Identity recognition systems allow plants to tailor competitive phenotypes in response to the genetic relatedness of neighbours. There is limited evidence for the existence of recognition systems in crop species and whether they operate at a level that would allow for identification of different degrees of relatedness. Here, we test the responses of commercial soya bean cultivars to neighbours of varying genetic relatedness consisting of other commercial cultivars (intraspecific), its wild progenitor Glycine soja, and another leguminous species Phaseolus vulgaris (interspecific). We found, for the first time to our knowledge, that a commercial soya bean cultivar, OAC Wallace, showed identity recognition responses to neighbours at different levels of genetic relatedness. OAC Wallace showed no response when grown with other commercial soya bean cultivars (intra-specific neighbours), showed increased allocation to leaves compared with stems with wild soya beans (highly related wild progenitor species), and increased allocation to leaves compared with stems and roots with white beans (interspecific neighbours). Wild soya bean also responded to identity recognition but these responses involved changes in biomass allocation towards stems instead of leaves suggesting that identity recognition responses are species-specific and consistent with the ecology of the species. In conclusion, elucidating identity recognition in crops may provide further knowledge into mechanisms of crop competition and the relationship between crop density and yield. PMID:28280587

Does the threshold for reporting musculoskeletal pain or the probability of attributing work-relatedness vary by socioeconomic position or sex?

Science.gov (United States)

Mehlum, Ingrid Sivesind; Kristensen, Petter; Veiersted, Kaj Bo; Wærsted, Morten; Punnett, Laura

2013-08-01

To examine the effect of sex and socioeconomic position (SEP) on individuals' perceptions of pain and its work-relatedness. We compared self-reported pain in neck-shoulder or arm with clinical diagnoses and workers' judgments of work-relatedness with physicians' assessments based on specific criteria, between sexes and high- and low-SEP participants in the Oslo Health Study (n = 217). Clinical diagnoses were more frequent in low-SEP subjects than high-SEP subjects with pain and generally higher in women than in men. Pain attributed to work was more frequently assessed as work-related by the physicians in low-SEP subjects than high-SEP subjects and in men than in women of low SEP. The threshold for reporting pain seemed higher in low-SEP subjects and among women. Physicians were more likely to agree with low-SEP workers about work-relatedness.

AUTONOMY AND RELATEDNESS IN MOTHER-TEEN INTERACTIONS AS PREDICTORS OF INVOLVEMENT IN ADOLESCENT DATING AGGRESSION.

Science.gov (United States)

Niolon, Phyllis Holditch; Kuperminc, Gabriel P; Allen, Joseph P

2015-04-01

This multi-method, longitudinal study examines the negotiation of autonomy and relatedness between teens and their mothers as etiologic predictors of perpetration and victimization of dating aggression two years later. Observations of 88 mid-adolescents and their mothers discussing a topic of disagreement were coded for each individual's demonstrations of autonomy and relatedness using a validated coding system. Adolescents self-reported on perpetration and victimization of physical and psychological dating aggression two years later. We hypothesized that mother's and adolescents' behaviors supporting autonomy and relatedness would longitudinally predict lower reporting of dating aggression, and that their behaviors inhibiting autonomy and relatedness would predict higher reporting of dating aggression. Hypotheses were not supported; main findings were characterized by interactions of sex and risk status with autonomy. Maternal behaviors supporting autonomy predicted higher reports of perpetration and victimization of physical dating aggression for girls, but not for boys. Adolescent behaviors supporting autonomy predicted higher reports of perpetration of physical dating aggression for high-risk adolescents, but not for low-risk adolescents. Results indicate that autonomy is a dynamic developmental process, operating differently as a function of social contexts in predicting dating aggression. Examination of these and other developmental processes within parent-child relationships is important in predicting dating aggression, but may depend on social context.

Genomic Inbreeding and Relatedness in Wild Panda Populations.

Science.gov (United States)

Garbe, John R; Prakapenka, Dzianis; Tan, Cheng; Da, Yang

2016-01-01

Inbreeding and relatedness in wild panda populations are important parameters for panda conservation. Habitat loss and fragmentation are expected to increase inbreeding but the actual inbreeding levels in natural panda habitats were unknown. Using 150,025 SNPs and 14,926 SNPs selected from published whole-genome sequences, we estimated genomic inbreeding coefficients and relatedness of 49 pandas including 34 wild pandas sampled from six habitats. Qinling and Liangshan pandas had the highest levels of inbreeding and relatedness measured by genomic inbreeding and coancestry coefficients, whereas the inbreeding levels in Qionglai and Minshan were 28-45% of those in Qinling and Liangshan. Genomic coancestry coefficients between pandas from different habitats showed that panda populations from the four largest habitats, Minshan, Qionglai, Qinling and Liangshan, were genetically unrelated. Pandas between these four habitats on average shared 66.0-69.1% common alleles and 45.6-48.6% common genotypes, whereas pandas within each habitat shared 71.8-77.0% common alleles and 51.7-60.4% common genotypes. Pandas in the smaller populations of Qinling and Liangshan were more similarly to each other than pandas in the larger populations of Qionglai and Minshan according to three genomic similarity measures. Panda genetic differentiation between these habitats was positively related to their geographical distances. Most pandas separated by 200 kilometers or more shared no common ancestral alleles. The results provided a genomic quantification of the actual levels of inbreeding and relatedness among pandas in their natural habitats, provided genomic confirmation of the relationship between genetic diversity and geographical distances, and provided genomic evidence to the urgency of habitat protection.

Genomic Inbreeding and Relatedness in Wild Panda Populations

Science.gov (United States)

Da, Yang

2016-01-01

Inbreeding and relatedness in wild panda populations are important parameters for panda conservation. Habitat loss and fragmentation are expected to increase inbreeding but the actual inbreeding levels in natural panda habitats were unknown. Using 150,025 SNPs and 14,926 SNPs selected from published whole-genome sequences, we estimated genomic inbreeding coefficients and relatedness of 49 pandas including 34 wild pandas sampled from six habitats. Qinling and Liangshan pandas had the highest levels of inbreeding and relatedness measured by genomic inbreeding and coancestry coefficients, whereas the inbreeding levels in Qionglai and Minshan were 28–45% of those in Qinling and Liangshan. Genomic coancestry coefficients between pandas from different habitats showed that panda populations from the four largest habitats, Minshan, Qionglai, Qinling and Liangshan, were genetically unrelated. Pandas between these four habitats on average shared 66.0–69.1% common alleles and 45.6–48.6% common genotypes, whereas pandas within each habitat shared 71.8–77.0% common alleles and 51.7–60.4% common genotypes. Pandas in the smaller populations of Qinling and Liangshan were more similarly to each other than pandas in the larger populations of Qionglai and Minshan according to three genomic similarity measures. Panda genetic differentiation between these habitats was positively related to their geographical distances. Most pandas separated by 200 kilometers or more shared no common ancestral alleles. The results provided a genomic quantification of the actual levels of inbreeding and relatedness among pandas in their natural habitats, provided genomic confirmation of the relationship between genetic diversity and geographical distances, and provided genomic evidence to the urgency of habitat protection. PMID:27494031

Behavior of bacteriome symbionts during transovarial transmission and development of the Asian citrus psyllid.

Directory of Open Access Journals (Sweden)

Hiroki Dan

Full Text Available The Asian citrus psyllid Diaphorina citri Kuwayama (Hemiptera: Liviidae is a serious pest worldwide, transmitting Candidatus Liberibacter spp. (Alphaproteobacteria, the causative agents of a devastating citrus disease known as huanglongbing or greening disease. In a symbiotic organ called the bacteriome, D. citri possesses an organelle-like defensive symbiont, Candidatus Profftella armatura (Betaproteobacteria, and a nutritional symbiont, Ca. Carsonella ruddii (Gammaproteobacteria. Drastically reduced symbiont genomes and metabolic complementarity among the symbionts and D. citri indicate their mutually indispensable association. Moreover, horizontal gene transfer between the Profftella and Liberibacter lineages suggests ecological and evolutionary interactions between the bacteriome symbiont and the HLB pathogen. Using fluorescence in situ hybridization, we examined the behavior of Profftella and Carsonella during transovarial transmission and the development of D. citri. In the bacteriomes of sexually-mature female adults, symbionts transformed from an extremely elongated tubular form into spherical or short-rod forms, which migrated toward the ovary. The symbionts then formed mosaic masses, which entered at the posterior pole of the vitellogenic oocytes. After anatrepsis, Carsonella and Profftella migrated to the central and peripheral parts of the mass, respectively. Following the appearance of host nuclei, the mass cellularized, segregating Carsonella and Profftella in the central syncytium and peripheral uninucleate bacteriocytes, respectively. Subsequently, the uninucleate bacteriocytes harboring Profftella assembled at the posterior pole, while the syncytium, containing Carsonella, sat on the anterior side facing the germ band initiating katatrepsis. During dorsal closure, the syncytium was divided into uninuclear bacteriocytes, which surrounded the mass of bacteriocytes containing Profftella. Once fully surrounded, the bacteriocyte mass

Symbiosis within Symbiosis: Evolving Nitrogen-Fixing Legume Symbionts.

Science.gov (United States)

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

2016-01-01

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

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

DEFF Research Database (Denmark)

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

2009-01-01

Evolutionary theory predicts that hosts are selected to prevent mixing of genetically different symbionts when competition among lineages reduces the productivity of a mutualism. The symbionts themselves may also defend their interests: recent studies of Acromyrmex leaf-cutting ants showed that s...

High Y-chromosomal diversity and low relatedness between paternal lineages on a communal scale in the Western European Low Countries during the surname establishment.

Science.gov (United States)

Larmuseau, M H D; Boon, N; Vanderheyden, N; Van Geystelen, A; Larmuseau, H F M; Matthys, K; De Clercq, W; Decorte, R

2015-07-01

There is limited knowledge on the biological relatedness between citizens and on the demographical dynamics within villages, towns and cities in pre-17th century Western Europe. By combining Y-chromosomal genotypes, in-depth genealogies and surname data in a strict genetic genealogical approach, it is possible to provide insights into the genetic diversity and the relatedness between indigenous paternal lineages within a particular community at the time of the surname adoption. To obtain these insights, six Flemish communities were selected in this study based on the differences in geography and historical development. After rigorous selection of appropriate DNA donors, low relatedness between Y chromosomes of different surnames was found within each community, although there is co-occurrence of these surnames in each community since the start of the surname adoption between the 14th and 15th century. Next, the high communal diversity in Y-chromosomal lineages was comparable with the regional diversity across Flanders at that time. Moreover, clinal distributions of particular Y-chromosomal lineages between the communities were observed according to the clinal distributions earlier observed across the Flemish regions and Western Europe. No significant indication for genetic differences between communities with distinct historical development was found in the analysis. These genetic results provide relevant information for studies in historical sciences, archaeology, forensic genetics and genealogy.

The Interplay of Autonomy and Relatedness in Hong Kong Chinese Single Mothers

Science.gov (United States)

Choy, Winnie C. W.; Moneta, Giovanni B.

2002-01-01

The mediating effects of autonomy and relatedness on the relationship between self-esteem and life satisfaction were investigated among 49 single mothers. Among all tested variables in the dimension of relatedness, only network orientation (propensity to utilize one's available social support) was a mediator of the positive relationship between…

Developing Intrinsic Motivation: Student Perceived Autonomy, Relatedness and Competence and the Relationship to Achievement

Science.gov (United States)

Heck, DeAnn M.

2013-01-01

This mixed methods action study examines the relationship of students' three psychological needs of autonomy, relatedness and competence as presented in the Self-Determination Theory (Deci & Ryan, 1985) to the level of achievement of high school seniors at Litchfield High School. In the quantitative phase of the study, the quantitative…

A Novel Extracellular Gut Symbiont in the Marine Worm Priapulus caudatus (Priapulida) Reveals an Alphaproteobacterial Symbiont Clade of the Ecdysozoa.

Science.gov (United States)

Kroer, Paul; Kjeldsen, Kasper U; Nyengaard, Jens R; Schramm, Andreas; Funch, Peter

2016-01-01

Priapulus caudatus (phylum Priapulida) is a benthic marine predatory worm with a cosmopolitan distribution. In its digestive tract we detected symbiotic bacteria that were consistently present in specimens collected over 8 years from three sites at the Swedish west coast. Based on their 16S rRNA gene sequence, these symbionts comprise a novel genus of the order Rickettsiales (Alphaproteobacteria). Electron microscopy and fluorescence in situ hybridization (FISH) identified them as extracellular, elongate bacteria closely associated with the microvilli, for which we propose the name "Candidatus Tenuibacter priapulorum". Within Rickettsiales, they form a phylogenetically well-defined, family-level clade with uncultured symbionts of marine, terrestrial, and freshwater arthropods. Cand. Tenuibacter priapulorum expands the host range of this candidate family from Arthropoda to the entire Ecdysozoa, which may indicate an evolutionary adaptation of this bacterial group to the microvilli-lined guts of the Ecdysozoa.

AUTONOMY AND RELATEDNESS IN MOTHER-TEEN INTERACTIONS AS PREDICTORS OF INVOLVEMENT IN ADOLESCENT DATING AGGRESSION

Science.gov (United States)

Niolon, Phyllis Holditch; Kuperminc, Gabriel P.; Allen, Joseph P.

2015-01-01

Objective This multi-method, longitudinal study examines the negotiation of autonomy and relatedness between teens and their mothers as etiologic predictors of perpetration and victimization of dating aggression two years later. Method Observations of 88 mid-adolescents and their mothers discussing a topic of disagreement were coded for each individual’s demonstrations of autonomy and relatedness using a validated coding system. Adolescents self-reported on perpetration and victimization of physical and psychological dating aggression two years later. We hypothesized that mother’s and adolescents’ behaviors supporting autonomy and relatedness would longitudinally predict lower reporting of dating aggression, and that their behaviors inhibiting autonomy and relatedness would predict higher reporting of dating aggression. Results Hypotheses were not supported; main findings were characterized by interactions of sex and risk status with autonomy. Maternal behaviors supporting autonomy predicted higher reports of perpetration and victimization of physical dating aggression for girls, but not for boys. Adolescent behaviors supporting autonomy predicted higher reports of perpetration of physical dating aggression for high-risk adolescents, but not for low-risk adolescents. Conclusions Results indicate that autonomy is a dynamic developmental process, operating differently as a function of social contexts in predicting dating aggression. Examination of these and other developmental processes within parent-child relationships is important in predicting dating aggression, but may depend on social context. PMID:25914852

Autonomy and Relatedness in Inner-City Families of Substance Abusing Adolescents

OpenAIRE

Samuolis, Jessica; Hogue, Aaron; Dauber, Sarah; Liddle, Howard A.

2006-01-01

This study examined parent-adolescent autonomous-relatedness functioning in inner-city, ethnic minority families of adolescents exhibiting drug abuse and related problem behaviors. Seventy-four parent-adolescent dyads completed a structured interaction task prior to the start of treatment that was coded using an established autonomous-relatedness measure. Adolescent drug use, externalizing, and internalizing behaviors were assessed. Parents and adolescents completed assessment instruments mea...

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

Science.gov (United States)

Gonella, Elena; Pajoro, Massimo; Marzorati, Massimo; Crotti, Elena; Mandrioli, Mauro; Pontini, Marianna; Bulgari, Daniela; Negri, Ilaria; Sacchi, Luciano; Chouaia, Bessem; Daffonchio, Daniele; Alma, Alberto

2015-11-13

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

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

KAUST Repository

Gonella, Elena

2015-11-13

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

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

Directory of Open Access Journals (Sweden)

William Leggat

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

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

Directory of Open Access Journals (Sweden)

James R White

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

Examining Evidence for Autonomy and Relatedness in Urban Inuit Parenting

Science.gov (United States)

McShane, Kelly E.; Hastings, Paul D.; Smylie, Janet K.; Prince, Conrad

2013-01-01

Inuit have experienced significant lifestyle changes in the past 50 years. Most recently, urbanization has resulted in greater numbers of Inuit living in urban centres in southern Canada. Little is known about Inuit parenting, and nothing has been published on Inuit parenting in an urban context. The present study sought to address this gap by describing the parenting of Inuit living in a large Canadian city and examining emergent themes for evidence of autonomy and relatedness. In partnership with the Tungasuvvingat Inuit Family Resource Centre, 39 Inuit parents completed an interview about their parenting experiences. Based on interviews, major parenting themes included: child characteristics; parenting behaviours and beliefs; affection and love; stressors; and responsive and respectful parenting. The majority of parenting themes linked to relatedness, although there was evidence of autonomy in both parenting behaviours and child characteristics. Results are interpreted in light of the autonomy–relatedness framework and theoretical implications of findings are discussed. PMID:23946698

The Emergence of Regional Immigrant Concentrations in USA and Australia: A Spatial Relatedness Approach

Science.gov (United States)

Novotny, Josef; Hasman, Jiri

2015-01-01

This paper examines the patterns of the US and Australian immigration geography and the process of regional population diversification and the emergence of new immigrant concentrations at the regional level. It presents a new approach in the context of human migration studies, focusing on spatial relatedness between individual foreign-born groups as revealed from the analysis of their joint spatial concentrations. The approach employs a simple assumption that the more frequently the members of two population groups concentrate in the same locations the higher is the probability that these two groups can be related. Based on detailed data on the spatial distribution of foreign-born groups in US counties (2000–2010) and Australian postal areas (2006–2011) we firstly quantify the spatial relatedness between all pairs of foreign-born groups and model the aggregate patterns of US and Australian immigration systems conceptualized as the undirected networks of foreign-born groups linked by their spatial relatedness. Secondly, adopting a more dynamic perspective, we assume that immigrant groups with higher spatial relatedness to those groups already concentrated in a region are also more likely to settle in this region in future. As the ultimate goal of the paper, we examine the power of spatial relatedness measures in projecting the emergence of new immigrant concentrations in the US and Australian regions. The results corroborate that the spatial relatedness measures can serve as useful instruments in the analysis of the patterns of population structure and prediction of regional population change. More generally, this paper demonstrates that information contained in spatial patterns (relatedness in space) of population composition has yet to be fully utilized in population forecasting. PMID:25966371

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

Directory of Open Access Journals (Sweden)

Paul eKroer

2016-04-01

Full Text Available Priapulus caudatus (phylum Priapulida is a benthic marine predatory worm with a cosmopolitan distribution. In its digestive tract we detected symbiotic bacteria that were consistently present in specimens collected over eight years from three sites at the Swedish west coast. Based on their 16S rRNA gene sequence, these symbionts comprise a novel genus of the order Rickettsiales (Alphaproteobacteria. Electron microscopy and fluorescence in situ hybridization (FISH identified them as extracellular, elongate bacteria closely associated with the microvilli, for which we propose the name ‘Candidatus Tenuibacter priapulorum’. Within Rickettsiales, they form a phylogenetically well-defined, family-level clade with uncultured symbionts of marine, terrestrial, and freshwater arthropods. Cand. Tenuibacter priapulorum expands the host range of this candidate family from Arthropoda to the entire Ecdysozoa, which may indicate an evolutionary adaptation of this bacterial group to the microvilli-lined guts of the Ecdysozoa.

Determination of genetic relatedness from low-coverage human genome sequences using pedigree simulations.

Science.gov (United States)

Martin, Michael D; Jay, Flora; Castellano, Sergi; Slatkin, Montgomery

2017-08-01

We develop and evaluate methods for inferring relatedness among individuals from low-coverage DNA sequences of their genomes, with particular emphasis on sequences obtained from fossil remains. We suggest the major factors complicating the determination of relatedness among ancient individuals are sequencing depth, the number of overlapping sites, the sequencing error rate and the presence of contamination from present-day genetic sources. We develop a theoretical model that facilitates the exploration of these factors and their relative effects, via measurement of pairwise genetic distances, without calling genotypes, and determine the power to infer relatedness under various scenarios of varying sequencing depth, present-day contamination and sequencing error. The model is validated by a simulation study as well as the analysis of aligned sequences from present-day human genomes. We then apply the method to the recently published genome sequences of ancient Europeans, developing a statistical treatment to determine confidence in assigned relatedness that is, in some cases, more precise than previously reported. As the majority of ancient specimens are from animals, this method would be applicable to investigate kinship in nonhuman remains. The developed software grups (Genetic Relatedness Using Pedigree Simulations) is implemented in Python and freely available. © 2017 John Wiley & Sons Ltd.

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

Directory of Open Access Journals (Sweden)

Tomáš Chrudimský

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

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

Science.gov (United States)

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

2012-01-01

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

Tapping the biotechnological potential of insect microbial symbionts: new insecticidal porphyrins.

Science.gov (United States)

Martinez, Ana Flávia Canovas; de Almeida, Luís Gustavo; Moraes, Luiz Alberto Beraldo; Cônsoli, Fernando Luís

2017-06-27

The demand for sustainable agricultural practices and the limited progress toward newer and safer chemicals for use in pest control maintain the impetus for research and identification of new natural molecules. Natural molecules are preferable to synthetic organic molecules because they are biodegradable, have low toxicity, are often selective and can be applied at low concentrations. Microbes are one source of natural insecticides, and microbial insect symbionts have attracted attention as a source of new bioactive molecules because these microbes are exposed to various selection pressures in their association with insects. Analytical techniques must be used to isolate and characterize new compounds, and sensitive analytical tools such as mass spectrometry and high-resolution chromatography are required to identify the least-abundant molecules. We used classical fermentation techniques combined with tandem mass spectrometry to prospect for insecticidal substances produced by the ant symbiont Streptomyces caniferus. Crude extracts from this bacterium showed low biological activity (less than 10% mortality) against the larval stage of the fall armyworm Spodoptera frugiperda. Because of the complexity of the crude extract, we used fractionation-guided bioassays to investigate if the low toxicity was related to the relative abundance of the active molecule, leading to the isolation of porphyrins as active molecules. Porphyrins are a class of photoactive molecules with a broad range of bioactivity, including insecticidal. The active fraction, containing a mixture of porphyrins, induced up to 100% larval mortality (LD 50  = 37.7 μg.cm -2 ). Tandem mass-spectrometry analyses provided structural information for two new porphyrin structures. Data on the availability of porphyrins in 67 other crude extracts of ant ectosymbionts were also obtained with ion-monitoring experiments. Insect-associated bacterial symbionts are a rich source of bioactive compounds. Exploring

Environmental Transmission of the Gut Symbiont Burkholderia to Phloem-Feeding Blissus insularis.

Science.gov (United States)

Xu, Yao; Buss, Eileen A; Boucias, Drion G

2016-01-01

The plant-phloem-feeding Blissus insularis possesses specialized midgut crypts, which harbor a dense population of the exocellular bacterial symbiont Burkholderia. Most individual B. insularis harbor a single Burkholderia ribotype in their midgut crypts; however, a diverse Burkholderia community exists within a host population. To understand the mechanism underlying the consistent occurrence of various Burkholderia in B. insularis and their specific association, we investigated potential gut symbiont transmission routes. PCR amplification detected a low titer of Burkholderia in adult reproductive tracts; however, fluorescence in situ hybridization assays failed to produce detectable signals in these tracts. Furthermore, no Burkholderia-specific PCR signals were detected in eggs and neonates, suggesting that it is unlikely that B. insularis prenatally transmits gut symbionts via ovarioles. In rearing experiments, most nymphs reared on St. Augustinegrass treated with cultured Burkholderia harbored the cultured Burkholderia strains. Burkholderia was detected in the untreated host grass of B. insularis, and most nymphs reared on untreated grass harbored a Burkholderia ribotype that was closely related to a plant-associated Burkholderia strain. These findings revealed that B. insularis neonates acquired Burkholderia primarily from the environment (i.e., plants and soils), even though the possibility of acquisition via egg surface cannot be excluded. In addition, our study explains how the diverse Burkholderia symbiont community in B. insularis populations can be maintained.

A novel bacterial symbiont in the nematode Spirocerca lupi

Directory of Open Access Journals (Sweden)

Gottlieb Yuval

2012-07-01

Full Text Available Abstract Background The parasitic nematode Spirocerca lupi (Spirurida: Thelaziidae, the canine esophageal worm, is the causative agent of spirocercosis, a disease causing morbidity and mortality in dogs. Spirocerca lupi has a complex life cycle, involving an obligatory coleopteran intermediate host (vector, an optional paratenic host, and a definitive canid host. The diagnosis of spirocercosis is challenging, especially in the early disease stages, when adult worms and clinical signs are absent. Thus, alternative approaches are needed to promote early diagnosis. The interaction between nematodes and their bacterial symbionts has recently become a focus of novel treatment regimens for other helminthic diseases. Results Using 16S rDNA-based molecular methods, here we found a novel bacterial symbiont in S. lupi that is closely related to Comamonas species (Brukholderiales: Comamonadaceae of the beta-proteobacteria. Its DNA was detected in eggs, larvae and adult stages of S. lupi. Using fluorescent in situ hybridization technique, we localized Comamonas sp. to the gut epithelial cells of the nematode larvae. Specific PCR enabled the detection of this symbiont's DNA in blood obtained from dogs diagnosed with spirocercosis. Conclusions The discovery of a new Comamonas sp. in S. lupi increase the complexity of the interactions among the organisms involved in this system, and may open innovative approaches for diagnosis and control of spirocercosis in dogs.

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

DEFF Research Database (Denmark)

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

2011-01-01

Fungus-growing ants display symbiont preference in behavioral assays, both towards the fungus they cultivate for food and Actinobacteria they maintain on their cuticle for antibiotic production against parasites. These Actinobacteria, genus Pseudonocardia Henssen (Pseudonocardiacea: Actinomycetales...

The relations among relatedness needs, subjective well-being, and depression of Korean elderly.

Science.gov (United States)

Seo, SuGyun; Jeon, JeeHye; Chong, YoungSook; An, JeongShin

2015-01-01

The first part of the study examined what the relatedness needs Korean elderly have in close relationships (spouse, children, friends) are. The most salient needs were "love and care" for spouse and "contact and often meeting" for children and friends. The second part of the study assessed the relations among the difference between expectation and satisfaction of relatedness needs, subjective well-being, and depression of Korean elderly. Regression analyses showed that the difference between expectation and satisfaction of relatedness needs for spouse and children significantly predicted subjective well-being and depression. Finally, gender differences are discussed in terms of the patriarchal culture of Korean society.

Infectious speciation revisited: impact of symbiont-depletion on female fitness and mating behavior of Drosophila paulistorum.

Directory of Open Access Journals (Sweden)

Wolfgang J Miller

2010-12-01

Full Text Available The neotropical Drosophila paulistorum superspecies, consisting of at least six geographically overlapping but reproductively isolated semispecies, has been the object of extensive research since at least 1955, when it was initially trapped mid-evolution in flagrant statu nascendi. In this classic system females express strong premating isolation patterns against mates belonging to any other semispecies, and yet uncharacterized microbial reproductive tract symbionts were described triggering hybrid inviability and male sterility. Based on theoretical models and limited experimental data, prime candidates fostering symbiont-driven speciation in arthropods are intracellular bacteria belonging to the genus Wolbachia. They are maternally inherited symbionts of many arthropods capable of manipulating host reproductive biology for their own benefits. However, it is an ongoing debate as to whether or not reproductive symbionts are capable of driving host speciation in nature and if so, to what extent. Here we have reevaluated this classic case of infectious speciation by means of present day molecular approaches and artificial symbiont depletion experiments. We have isolated the α-proteobacteria Wolbachia as the maternally transmitted core endosymbionts of all D. paulistorum semispecies that have coevolved towards obligate mutualism with their respective native hosts. In hybrids, however, these mutualists transform into pathogens by overreplication causing embryonic inviability and male sterility. We show that experimental reduction in native Wolbachia titer causes alterations in sex ratio, fecundity, and mate discrimination. Our results indicate that formerly designated Mycoplasma-like organisms are most likely Wolbachia that have evolved by becoming essential mutualistic symbionts in their respective natural hosts; they have the potential to trigger pre- and postmating isolation. Furthermore, in light of our new findings, we revisit the concept of

Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia: Mollusca).

Science.gov (United States)

Cavanaugh, C M; Abbott, M S; Veenhuis, M

1988-10-01

The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP(2)Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large subunit of RbuP(2)Case from tobacco (Nicotiana tabacum) cross-reacted on immunoblots with a protein of similar molecular mass occurring in extracts of the symbiont-containing gill tissue of S. velum. No cross-reactivity was detected in symbiont-free tissue extracts. The antiserum also cross-reacted in immunoblots with proteins of Thiobacillus neapolitanus, a free-living sulfuroxidizing chemoautotroph whose RbuP(2)Case has been well characterized. In protein A-gold immunoelectron microscopy studies, this antiserum consistently labeled the symbionts but not surrounding host gill tissue, indicating that the symbionts are responsible for the RbuP(2)Case activity.

Recommender System for E-Learning Based on Semantic Relatedness of Concepts

Directory of Open Access Journals (Sweden)

Mao Ye

2015-08-01

Full Text Available Digital publishing resources contain a lot of useful and authoritative knowledge. It may be necessary to reorganize the resources by concepts and recommend the related concepts for e-learning. A recommender system is presented in this paper based on the semantic relatedness of concepts computed by texts from digital publishing resources. Firstly, concepts are extracted from encyclopedias. Information in digital publishing resources is then reorganized by concepts. Secondly, concept vectors are generated by skip-gram model and semantic relatedness between concepts is measured according to the concept vectors. As a result, the related concepts and associated information can be recommended to users by the semantic relatedness for learning or reading. History data or users’ preferences data are not needed for recommendation in a specific domain. The technique may not be language-specific. The method shows potential usability for e-learning in a specific domain.

Pacific Islanders and Amerindian relatedness according to HLA ...

African Journals Online (AJOL)

groups of populations, like the presence of South American sweet potato in earlier .... Aymara (Bolivia), Uros (Peru) and Lamas (Peru) populations were .... Redish to yellow colours mean a gradient of HLA relatedness according to geography.

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

Science.gov (United States)

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

2016-11-01

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

High intraspecific genome diversity in the model arbuscular mycorrhizal symbiont Rhizophagus irregularis.

Science.gov (United States)

Chen, Eric C H; Morin, Emmanuelle; Beaudet, Denis; Noel, Jessica; Yildirir, Gokalp; Ndikumana, Steve; Charron, Philippe; St-Onge, Camille; Giorgi, John; Krüger, Manuela; Marton, Timea; Ropars, Jeanne; Grigoriev, Igor V; Hainaut, Matthieu; Henrissat, Bernard; Roux, Christophe; Martin, Francis; Corradi, Nicolas

2018-01-22

Arbuscular mycorrhizal fungi (AMF) are known to improve plant fitness through the establishment of mycorrhizal symbioses. Genetic and phenotypic variations among closely related AMF isolates can significantly affect plant growth, but the genomic changes underlying this variability are unclear. To address this issue, we improved the genome assembly and gene annotation of the model strain Rhizophagus irregularis DAOM197198, and compared its gene content with five isolates of R. irregularis sampled in the same field. All isolates harbor striking genome variations, with large numbers of isolate-specific genes, gene family expansions, and evidence of interisolate genetic exchange. The observed variability affects all gene ontology terms and PFAM protein domains, as well as putative mycorrhiza-induced small secreted effector-like proteins and other symbiosis differentially expressed genes. High variability is also found in active transposable elements. Overall, these findings indicate a substantial divergence in the functioning capacity of isolates harvested from the same field, and thus their genetic potential for adaptation to biotic and abiotic changes. Our data also provide a first glimpse into the genome diversity that resides within natural populations of these symbionts, and open avenues for future analyses of plant-AMF interactions that link AMF genome variation with plant phenotype and fitness. © 2018 The Authors. New Phytologist © 2018 New Phytologist Trust.

The Calyptogena magnifica chemoautotrophic symbiont genome

Energy Technology Data Exchange (ETDEWEB)

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

2007-03-01

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

High Y-chromosomal diversity and low relatedness between paternal lineages on a communal scale in the Western European Low Countries during the surname establishment

OpenAIRE

Larmuseau, M H D; Boon, N; Vanderheyden, N; Van Geystelen, A; Larmuseau, H F M; Matthys, K; De Clercq, W; Decorte, R

2015-01-01

There is limited knowledge on the biological relatedness between citizens and on the demographical dynamics within villages, towns and cities in pre-17th century Western Europe. By combining Y-chromosomal genotypes, in-depth genealogies and surname data in a strict genetic genealogical approach, it is possible to provide insights into the genetic diversity and the relatedness between indigenous paternal lineages within a particular community at the time of the surname adoption. To obtain thes...

Relatedness decreases and reciprocity increases cooperation in Norway rats.

Science.gov (United States)

Schweinfurth, Manon K; Taborsky, Michael

2018-03-14

Kin selection and reciprocity are two mechanisms underlying the evolution of cooperation, but the relative importance of kinship and reciprocity for decisions to cooperate are yet unclear for most cases of cooperation. Here, we experimentally tested the relative importance of relatedness and received cooperation for decisions to help a conspecific in wild-type Norway rats ( Rattus norvegicus ). Test rats provided more food to non-kin than to siblings, and they generally donated more food to previously helpful social partners than to those that had refused help. The rats thus applied reciprocal cooperation rules irrespective of relatedness, highlighting the importance of reciprocal help for cooperative interactions among both related and unrelated conspecifics. © 2018 The Author(s).

Why wasp foundresses change nests: relatedness, dominance, and nest quality.

Directory of Open Access Journals (Sweden)

Perttu Seppä

Full Text Available The costs and benefits of different social options are best understood when individuals can be followed as they make different choices, something that can be difficult in social insects. In this detailed study, we follow overwintered females of the social wasp Polistes carolina through different nesting strategies in a stratified habitat where nest site quality varies with proximity to a foraging area, and genetic relatedness among females is known. Females may initiate nests, join nests temporarily or permanently, or abandon nests. Females can become helpers or egglayers, effectively workers or queens. What they actually do can be predicted by a combination of ecological and relatedness factors. Advantages through increased lifetime success of individuals and nests drives foundresses of the social wasp Polistes from solitary to social nest founding. We studied reproductive options of spring foundresses of P. carolina by monitoring individually-marked wasps and assessing reproductive success of each foundress by using DNA microsatellites. We examined what behavioral decisions foundresses make after relaxing a strong ecological constraint, shortage of nesting sites. We also look at the reproductive consequences of different behaviors. As in other Polistes, the most successful strategy for a foundress was to initiate a nest as early as possible and then accept others as subordinates. A common feature for many P. carolina foundresses was, however, that they reassessed their reproductive options by actively monitoring other nests at the field site and sometimes moving permanently to new nests should that offer better (inclusive fitness prospects compared to their original nests. A clear motivation for moving to new nests was high genetic relatedness; by the end of the foundress period all females were on nests with full sisters.

Why Wasp Foundresses Change Nests: Relatedness, Dominance, and Nest Quality

Science.gov (United States)

Seppä, Perttu; Queller, David C.; Strassmann, Joan E.

2012-01-01

The costs and benefits of different social options are best understood when individuals can be followed as they make different choices, something that can be difficult in social insects. In this detailed study, we follow overwintered females of the social wasp Polistes carolina through different nesting strategies in a stratified habitat where nest site quality varies with proximity to a foraging area, and genetic relatedness among females is known. Females may initiate nests, join nests temporarily or permanently, or abandon nests. Females can become helpers or egglayers, effectively workers or queens. What they actually do can be predicted by a combination of ecological and relatedness factors. Advantages through increased lifetime success of individuals and nests drives foundresses of the social wasp Polistes from solitary to social nest founding. We studied reproductive options of spring foundresses of P. carolina by monitoring individually-marked wasps and assessing reproductive success of each foundress by using DNA microsatellites. We examined what behavioral decisions foundresses make after relaxing a strong ecological constraint, shortage of nesting sites. We also look at the reproductive consequences of different behaviors. As in other Polistes, the most successful strategy for a foundress was to initiate a nest as early as possible and then accept others as subordinates. A common feature for many P. carolina foundresses was, however, that they reassessed their reproductive options by actively monitoring other nests at the field site and sometimes moving permanently to new nests should that offer better (inclusive) fitness prospects compared to their original nests. A clear motivation for moving to new nests was high genetic relatedness; by the end of the foundress period all females were on nests with full sisters. PMID:23049791

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

Science.gov (United States)

Friesen, M L; Mathias, A

2010-02-01

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

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

KAUST Repository

Chen, Jit Ern

2017-10-20

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

Distribution of individual inbreeding coefficients, relatedness and influence of stocking on native anadromous brown trout ( Salmo trutta ) population structure

DEFF Research Database (Denmark)

Ruzzante, D.E.; Hansen, Michael Møller; Meldrup, Dorte

2001-01-01

inbreeding coefficients do not differ among locations within rivers. Relatedness varies between sites within rivers indicating varied local dynamics at a very small geographical scale. Relatedness is sometimes lower than expected among an equal number of simulated individuals with randomized genotypes......, the proportion of locally assigned trout correlates with the populations' stocking histories, with rivers presently subjected to stocking (hatchery trout) showing low mean similar to0.73), and rivers where stocking was discontinued showing high (mean similar to0.84) proportions of local fish, probably reflecting...

Multibusiness firms and performance in Italy. What role does relatedness play?

Directory of Open Access Journals (Sweden)

Maurizio La Rocca

2018-05-01

Full Text Available This paper evaluates the effect of diversification strategy on corporate value for a sample of Italian companies. It accounts for both the level of diversification and relatedness components. Empirical analyses show a U-shaped curvilinear relationship between diversification and value. In contrast to the mainstream literature, our results highlight that related diversification has a negative effect, while unrelated diversification is a value-creating strategy. JEL classification: L25, M10, Keywords: Product diversification, Multi-business firm, Relatedness, Firm performance, Firm value

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

KAUST Repository

Ziegler, Maren; Arif, Chatchanit; Burt, John A.; Dobretsov, Sergey; Roder, Cornelia; Lajeunesse, Todd C.; Voolstra, Christian R.

2017-01-01

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

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

KAUST Repository

Ziegler, Maren

2017-01-02

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

Influence of CH4 and H2S availability on symbiont distribution, carbon assimilation and transfer in the dual symbiotic vent mussel Bathymodiolus azoricus

Directory of Open Access Journals (Sweden)

R. S. Santos

2008-12-01

Full Text Available High densities of mussels of the genus Bathymodiolus are present at hydrothermal vents of the Mid-Atlantic Ridge. It was previously proposed that the chemistry at vent sites would affect their sulphide- and methane-oxidizing endosymbionts' abundance. In this study, we confirmed the latter assumption using fluorescence in situ hybridization on Bathymodiolus azoricus specimens maintained in a controlled laboratory environment at atmospheric pressure with one, both or none of the chemical substrates. A high level of symbiosis plasticity was observed, methane-oxidizers occupying between 4 and 39% of total bacterial area and both symbionts developing according to the presence or absence of their substrates. Using H13CO3− in the presence of sulphide, or 13CH4, we monitored carbon assimilation by the endosymbionts and its translocation to symbiont-free mussel tissues. Carbon was incorporated from methane and sulphide-oxidized inorganic carbon at rates 3 to 10 times slower in the host muscle tissue than in the symbiont-containing gill tissue. Both symbionts thus contribute actively to B. azoricus nutrition and adapt to the availability of their substrates. Further experiments with varying substrate concentrations using the same set-up should provide useful tools to study and even model the effects of changes in hydrothermal fluids on B. azoricus' chemosynthetic nutrition.

The Physiology of Microbial Symbionts in Fungus-Farming Termites

DEFF Research Database (Denmark)

Rodrigues da Costa, Rafael

. The termites provide the fungus with optimal growth conditions (e.g., stable temperature and humidity), as well as with constant inoculation of growth substrate and protection against alien fungi. In reward, the fungus provides the termites with a protein-rich fungal biomass based diet. In addition...... with their symbionts are main decomposer of organic matter in Africa, and this is reflect of a metabolic complementarity to decompose plant biomass in the genome of the three organisms involved in this symbiosis. Many of the physiological aspects of this symbiosis remain obscure, and here I focus on physiology...... of microbial symbionts associated with fungus-growing termites. Firstly, by using a set of enzyme assays, plant biomass compositional analyses, and RNA sequencing we gained deeper understanding on what enzymes are produced and active at different times of the decomposition process. Our results show that enzyme...

Increased nature relatedness and decreased authoritarian political views after psilocybin for treatment-resistant depression.

Science.gov (United States)

Lyons, Taylor; Carhart-Harris, Robin L

2018-01-01

Previous research suggests that classical psychedelic compounds can induce lasting changes in personality traits, attitudes and beliefs in both healthy subjects and patient populations. Here we sought to investigate the effects of psilocybin on nature relatedness and libertarian-authoritarian political perspective in patients with treatment-resistant depression (TRD). This open-label pilot study with a mixed-model design studied the effects of psilocybin on measures of nature relatedness and libertarian-authoritarian political perspective in patients with moderate to severe TRD ( n=7) versus age-matched non-treated healthy control subjects ( n=7). Psilocybin was administered in two oral dosing sessions (10 mg and 25 mg) 1 week apart. Main outcome measures were collected 1 week and 7-12 months after the second dosing session. Nature relatedness and libertarian-authoritarian political perspective were assessed using the Nature Relatedness Scale (NR-6) and Political Perspective Questionnaire (PPQ-5), respectively. Nature relatedness significantly increased ( t(6)=-4.242, p=0.003) and authoritarianism significantly decreased ( t(6)=2.120, p=0.039) for the patients 1 week after the dosing sessions. At 7-12 months post-dosing, nature relatedness remained significantly increased ( t(5)=-2.707, p=0.021) and authoritarianism remained decreased at trend level ( t(5)=-1.811, p=0.065). No differences were found on either measure for the non-treated healthy control subjects. This pilot study suggests that psilocybin with psychological support might produce lasting changes in attitudes and beliefs. Although it would be premature to infer causality from this small study, the possibility of drug-induced changes in belief systems seems sufficiently intriguing and timely to deserve further investigation.

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

Science.gov (United States)

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

2012-01-01

The yellow mealworm, Tenebrio molitor, harbors a symbiont that has spores with a thick, laminated wall and infects the fat body and ventral nerve chord of adult and larval beetles. In adult males, there is heavy infection of the epithelial cells of the testes and between testes lobes with occasional penetration of the lobes. Spores are enveloped in the spermatophores when they are formed at the time of mating and transferred to the female's bursa copulatrix. Infection has not been found in the ovaries. The sequence of the nuclear small subunit rDNA indicates that the symbiont is a member of the Ichthyosporea, a class of protists near the animal-fungi divergence. © 2012 The Author(s) Journal of Eukaryotic Microbiology © 2012 International Society of Protistologists.

The Biological Nature of Geochemical Proxies: algal symbionts affect coral skeletal chemistry

Science.gov (United States)

Owens, K.; Cohen, A. L.; Shimizu, N.

2001-12-01

The strontium-calcium ratio (Sr/Ca) of reef coral skeleton is an important ocean temperature proxy that has been used to address some particularly controversial climate change issues. However, the paleothermometer has sometimes proven unreliable and there are indications that the temperature-dependence of Sr/Ca in coral aragonite is linked to the photosynthetic activity of algal symbionts (zooxanthellae) in coral tissue. We examined the effect of algal symbiosis on skeletal chemistry using Astrangia danae, a small colonial temperate scleractinian that occurs naturally with and without zooxanthellae. Live symbiotic (deep brown) and asymbiotic (white) colonies of similar size were collected in Woods Hole where water temperatures fluctuate seasonally between -2oC and 23oC. We used a microbeam technique (Secondary Ion Mass Spectrometry) and a 30 micron diameter sampling beam to construct high-resolution Sr/Ca profiles, 2500 microns long, down the growth axes of the outer calical (thecal) walls. Profiles generated from co-occuring symbiotic and asymbiotic colonies are remarkably different despite their exposure to identical water temperatures. Symbiotic coral Sr/Ca displays four large-amplitude annual cycles with high values in the winter, low values in the summer and a temperature dependence similar to that of tropical reef corals. By comparison, Sr/Ca profiles constructed from asymbiotic coral skeleton display little variability over the same time period. Asymbiont Sr/Ca is relatively insensitive to the enormous temperature changes experienced over the year; the temperature dependence is similar to that of nighttime skeletal deposits in tropical reef corals and non-biological aragonite precipitates. We propose that the large variations in skeletal Sr/Ca observed in all symbiont-hosting coral species are not related to SST variability per se but are driven primarily by large seasonal variations in skeletal calcification rate associated with symbiont photosynthesis. Our

An Intervention to Improve Teachers' Interpersonally Involving Instructional Practices in High School Physical Education: Implications for Student Relatedness Support and In-Class Experiences.

Science.gov (United States)

Sparks, Cassandra; Lonsdale, Chris; Dimmock, James; Jackson, Ben

2017-04-01

Research grounded in self-determination theory has demonstrated the important role of teachers in shaping students' physical education experiences. Utilizing a cluster-randomized controlled design, this study aimed to examine whether an interpersonally involving training program based on self-determination theory principles could enhance students' in-class experiences. With 18 teachers (males = 8, females = 10, M age  = 32.75, SD = 8.14) and a final sample of 382 students (males = 155, females = 227, M age  = 13.20, SD = 1.66), we implemented linear mixed modeling to investigate the effects on students' (a) perceived relatedness support and (b) enjoyment of physical education, tripartite efficacy beliefs (i.e., self-efficacy, other-efficacy, relation-inferred self-efficacy), self-determined motivation, and amotivation. Relative to those in the control condition, students in the treatment condition reported positive changes in teacher-provided relatedness support, enjoyment, other-efficacy, and peer-focused relation-inferred self-efficacy. These findings demonstrate support for strategies designed to aid physical education teachers' relatedness-supportive instructional behaviors.

Ancestral genetic diversity associated with the rapid spread of stress-tolerant coral symbionts in response to Holocene climate change

KAUST Repository

Hume, Benjamin C. C.

2016-04-05

Coral communities in the Persian/Arabian Gulf (PAG) withstand unusually high salinity levels and regular summer temperature maxima of up to ∼35 °C that kill conspecifics elsewhere. Due to the recent formation of the PAG and its subsequent shift to a hot climate, these corals have had only <6, 000 y to adapt to these extreme conditions and can therefore inform on how coral reefs may respond to global warming. One key to coral survival in the world\\'s warmest reefs are symbioses with a newly discovered alga, Symbiodinium thermophilum. Currently, it is unknown whether this symbiont originated elsewhere or emerged from unexpectedly fast evolution catalyzed by the extreme environment. Analyzing genetic diversity of symbiotic algae across >5, 000 km of the PAG, the Gulf of Oman, and the Red Sea coastline, we show that S. thermophilum is a member of a highly diverse, ancient group of symbionts cryptically distributed outside the PAG. We argue that the adjustment to temperature extremes by PAG corals was facilitated by the positive selection of preadapted symbionts. Our findings suggest that maintaining the largest possible pool of potentially stress-tolerant genotypes by protecting existing biodiversity is crucial to promote rapid adaptation to present-day climate change, not only for coral reefs, but for ecosystems in general.

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

DEFF Research Database (Denmark)

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

Earthworms harbor in their nephridia (excretory organs) symbiotic bacteria which densely colonize a specific part of the nephridia, called the ampulla [1]. The symbiosis is species-specific and the symbionts form their own monophyletic genus Verminephrobacter (β-proteobacteria) [2] and are vertic......,J. 1926. Z Morph Ökol Tiere, 6(3):588-624. [2] Schramm,A. et al. 2003. Environ Microbiol 5(9):804-809. [3] Davidson,S.K. & Stahl,D.A. 2006. Appl Environ Microbiol 72(1):769-775. [4] Pandazis,G. 1931. Zentralbl Bakteriol 120:440-453.......Earthworms harbor in their nephridia (excretory organs) symbiotic bacteria which densely colonize a specific part of the nephridia, called the ampulla [1]. The symbiosis is species-specific and the symbionts form their own monophyletic genus Verminephrobacter (β-proteobacteria) [2...... showed no significant differences in growth rate and fecundity between symbiotic and aposymbiotic worms. Thus the symbionts do not appear to have an effect on worm fitness, under growth conditions tested. The underlying functional and maintaining mechanisms of this symbiosis remain a conundrum. [1] Knop...

Unsatisfied relatedness, not competence or autonomy, increases trait anger through the right amygdala.

Science.gov (United States)

Wang, Yinan; Kong, Feng; Kong, Xiangzhen; Zhao, Yuanfang; Lin, Danhua; Liu, Jia

2017-10-01

Anger is a common negative emotion in social life. Behavioral research suggests that unsatisfied relatedness, autonomy, and competence are related to anger. However, it remains unclear whether these unsatisfied needs all contribute to anger or just a particular unsatisfied need is the main source of anger. In addition, little is known about the neural substrate between unsatisfied needs and anger. To address these two questions, we used voxel-based morphometry (VBM) to explore the neural substrate underlying the relation between unsatisfied needs and trait anger. Behaviorally, we found that although all three unsatisfied needs were correlated with trait anger, unsatisfied relatedness was the only factor that was uniquely related to trait anger. Neurally, the gray matter volume of the right amygdala was correlated with trait anger, which fits nicely with the role of the amygdala as a core region for processing anger. Importantly, the right amygdala mediated the total effect of unsatisfied relatedness on trait anger, even after controlling for general personality dispositions. Our results contribute to the theoretical conceptualization of anger by elucidating the unique role of unsatisfied relatedness in anger and the neural substrate underlying such relation.

Genetic relatedness of orbiviruses by RNA-RNA blot hybridization

International Nuclear Information System (INIS)

Bodkin, D.K.

1985-01-01

RNA-RNA blot hybridization was developed in order to identify type-specific genes among double-stranded (ds) RNA viruses, to assess the genetic relatedness of dsRNA viruses and to classify new strains. Viral dsRNA segments were electrophoresed through 10% polyacrylamide gels, transferred to membranes, and hybridized to [5' 32 P]-pCp labeled genomic RNA from a related strain. Hybridization was performed at 52 0 C, 50% formamide, 5X SSC. Under these conditions heterologous RNA species must share ≥ 74% sequence homology in order to form stable dsRNA hybrids. Cognate genes of nine members of the Palyam serogroup of orbiviruses were identified and their sequence relatedness to the prototype. Palyam virus, was determined. Reciprocal blot hybridizations were performed using radiolabeled genomic RNA of all members of the Palyam serogroup. Unique and variant genes were identified by lack of cross-homology or by weak homology between segments. Since genes 2 and 6 exhibited the highest degree of sequence variability, response to the vertebrate immune system may be a major cause of sequence divergence among members of a single serogroup. Changuinola serogroup isolates were compared by dot-blot hybridization, while Colorado tick fever (CTF) serogroup isolates were compared by the RNA-RNA blot hybridization procedure described for reovirus and Palyam serogroup isolates. Preliminary blot hybridization data were also obtained on the relatedness of members of different Orbivirus serogroups

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

Science.gov (United States)

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

1987-01-01

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

Neighbourhood density and genetic relatedness interact to determine fruit set and abortion rates in a continuous tropical tree population.

Science.gov (United States)

Jones, F A; Comita, L S

2008-12-07

Tropical trees may show positive density dependence in fruit set and maturation due to pollen limitation in low-density populations. However, pollen from closely related individuals in the local neighbourhood might reduce fruit set or increase fruit abortion in self-incompatible tree species. We investigated the role of neighbourhood density and genetic relatedness on individual fruit set and abortion in the neotropical tree Jacaranda copaia in a large forest plot in central Panama. Using nested neighbourhood models, we found a strong positive effect of increased conspecific density on fruit set and maturation. However, high neighbourhood genetic relatedness interacted with density to reduce total fruit set and increase the proportion of aborted fruit. Our results imply a fitness advantage for individuals growing in high densities as measured by fruit set, but realized fruit set is lowered by increased neighbourhood relatedness. We hypothesize that the mechanism involved is increased visitation by density-dependent invertebrate pollinators in high-density populations, which increases pollen quantity and carry-over and increases fruit set and maturation, coupled with self-incompatibility at early and late stages due to biparental inbreeding that lowers fruit set and increases fruit abortion. Implications for the reproductive ecology and conservation of tropical tree communities in continuous and fragmented habitats are discussed.

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

Science.gov (United States)

Luna-Ramirez, Karen; Skaljac, Marisa; Grotmann, Jens; Kirfel, Phillipp; Vilcinskas, Andreas

2017-08-24

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

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

Directory of Open Access Journals (Sweden)

Karen Luna-Ramirez

2017-08-01

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

Autism Spectrum Disorder, Intellectual Disability, and Emotional Functioning: Relatedness and Particular Impact on Challenging Behavior

NARCIS (Netherlands)

Sappok, Tanja; Sterkenburg, Paula; Bohm, Julia

2017-01-01

Aims: Persons with an intellectual disability (ID) show high rates of challenging behaviour (CB), especially in cases of co-occurring autism spectrum disorder (ASD). The aim of this retrospective study was to examine the relatedness and impact of ASD, the severity of ID, and the level of emotional

Complete Genome Sequence of the Soybean Symbiont Bradyrhizobium japonicum Strain USDA6T

Directory of Open Access Journals (Sweden)

Nobukazu Uchiike

2011-10-01

Full Text Available The complete nucleotide sequence of the genome of the soybean symbiont Bradyrhizobium japonicum strain USDA6T was determined. The genome of USDA6T is a single circular chromosome of 9,207,384 bp. The genome size is similar to that of the genome of another soybean symbiont, B. japonicum USDA110 (9,105,828 bp. Comparison of the whole-genome sequences of USDA6T and USDA110 showed colinearity of major regions in the two genomes, although a large inversion exists between them. A significantly high level of sequence conservation was detected in three regions on each genome. The gene constitution and nucleotide sequence features in these three regions indicate that they may have been derived from a symbiosis island. An ancestral, large symbiosis island, approximately 860 kb in total size, appears to have been split into these three regions by unknown large-scale genome rearrangements. The two integration events responsible for this appear to have taken place independently, but through comparable mechanisms, in both genomes.

Host-symbiont recombination versus natural selection in the response of coral-dinoflagellate symbioses to environmental disturbance.

Science.gov (United States)

LaJeunesse, Todd C; Smith, Robin; Walther, Mariana; Pinzón, Jorge; Pettay, Daniel T; McGinley, Michael; Aschaffenburg, Matthew; Medina-Rosas, Pedro; Cupul-Magaña, Amilcar L; Pérez, Andrés López; Reyes-Bonilla, Hector; Warner, Mark E

2010-10-07

Mutualisms between reef-building corals and endosymbiotic dinoflagellates are particularly sensitive to environmental stress, yet the ecosystems they construct have endured major oscillations in global climate. During the winter of 2008, an extreme cold-water event occurred in the Gulf of California that bleached corals in the genus Pocillopora harbouring a thermally 'sensitive' symbiont, designated Symbiodinium C1b-c, while colonies possessing Symbiodinium D1 were mostly unaffected. Certain bleached colonies recovered quickly while others suffered partial or complete mortality. In most colonies, no appreciable change was observed in the identity of the original symbiont, indicating that these partnerships are stable. During the initial phases of recovery, a third species of symbiont B1(Aiptasia), genetically identical to that harboured by the invasive anemone, Aiptasia sp., grew opportunistically and was visible as light-yellow patches on the branch tips of several colonies. However, this symbiont did not persist and was displaced in all cases by C1b-c several months later. Colonies with D1 were abundant at inshore habitats along the continental eastern Pacific, where seasonal turbidity is high relative to offshore islands. Environmental conditions of the central and southern coasts of Mexico were not sufficient to explain the exclusivity of D1 Pocillopora in these regions. It is possible that mass mortalities associated with major thermal disturbances during the 1997-1998 El Niño Southern Oscillation eliminated C1b-c holobionts from these locations. The differential loss of Pocillopora holobionts in response to thermal stress suggests that natural selection on existing variation can cause rapid and significant shifts in the frequency of particular coral-algal partnerships. However, coral populations may take decades to recover following episodes of severe selection, thereby raising considerable uncertainty about the long-term viability of these communities.

Host–symbiont recombination versus natural selection in the response of coral–dinoflagellate symbioses to environmental disturbance

Science.gov (United States)

LaJeunesse, Todd C.; Smith, Robin; Walther, Mariana; Pinzón, Jorge; Pettay, Daniel T.; McGinley, Michael; Aschaffenburg, Matthew; Medina-Rosas, Pedro; Cupul-Magaña, Amilcar L.; Pérez, Andrés López; Reyes-Bonilla, Hector; Warner, Mark E.

2010-01-01

Mutualisms between reef-building corals and endosymbiotic dinoflagellates are particularly sensitive to environmental stress, yet the ecosystems they construct have endured major oscillations in global climate. During the winter of 2008, an extreme cold-water event occurred in the Gulf of California that bleached corals in the genus Pocillopora harbouring a thermally ‘sensitive’ symbiont, designated Symbiodinium C1b-c, while colonies possessing Symbiodinium D1 were mostly unaffected. Certain bleached colonies recovered quickly while others suffered partial or complete mortality. In most colonies, no appreciable change was observed in the identity of the original symbiont, indicating that these partnerships are stable. During the initial phases of recovery, a third species of symbiont B1Aiptasia, genetically identical to that harboured by the invasive anemone, Aiptasia sp., grew opportunistically and was visible as light-yellow patches on the branch tips of several colonies. However, this symbiont did not persist and was displaced in all cases by C1b-c several months later. Colonies with D1 were abundant at inshore habitats along the continental eastern Pacific, where seasonal turbidity is high relative to offshore islands. Environmental conditions of the central and southern coasts of Mexico were not sufficient to explain the exclusivity of D1 Pocillopora in these regions. It is possible that mass mortalities associated with major thermal disturbances during the 1997–1998 El Niño Southern Oscillation eliminated C1b-c holobionts from these locations. The differential loss of Pocillopora holobionts in response to thermal stress suggests that natural selection on existing variation can cause rapid and significant shifts in the frequency of particular coral–algal partnerships. However, coral populations may take decades to recover following episodes of severe selection, thereby raising considerable uncertainty about the long-term viability of these communities

Characterization of a Newly Discovered Symbiont of the Whitefly Bemisia tabaci (Hemiptera: Aleyrodidae)

Science.gov (United States)

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

2013-01-01

Bemisia tabaci (Hemiptera: Aleyrodidae) is a species complex containing >28 cryptic species, some of which are important crop pests worldwide. Like many other sap-sucking insects, whiteflies harbor an obligatory symbiont, “Candidatus Portiera aleyrodidarum,” and a number of secondary symbionts. So far, six genera of secondary symbionts have been identified in B. tabaci. In this study, we report and describe the finding of an additional bacterium in the indigenous B. tabaci cryptic species China 1 (formerly known as B. tabaci biotype ZHJ3). Phylogenetic analysis based on the 16S rRNA and gltA genes showed that the bacterium belongs to the Alphaproteobacteria subdivision of the Proteobacteria and has a close relationship with human pathogens of the genus Orientia. Consequently, we temporarily named it Orientia-like organism (OLO). OLO was found in six of eight wild populations of B. tabaci China 1, with the infection rate ranging from 46.2% to 76.8%. Fluorescence in situ hybridization (FISH) of B. tabaci China 1 in nymphs and adults revealed that OLOs are confined to the bacteriome and co-occur with “Ca. Portiera aleyrodidarum.” The vertical transmission of OLO was demonstrated by detection of OLO at the anterior pole end of the oocytes through FISH. Quantitative PCR analysis of population dynamics suggested a complex interaction between “Ca. Portiera aleyrodidarum” and OLO. Based on these results, we propose “Candidatus Hemipteriphilus asiaticus” for the classification of this symbiont from B. tabaci. PMID:23144129

Coordination, Competition, and Neutrality: Autonomy and Relatedness Patterns in Girls' Interactions with Mentors and Peers

Science.gov (United States)

Patton, Christine L.; Deutsch, Nancy L.; Das, Anindita

2016-01-01

Healthy development necessitates that adolescents maintain connections with others while developing an autonomous identity. In the extant literature, however, autonomy and relatedness are often placed at odds, particularly in discussions of girls. We explore how autonomy and relatedness co-occur in girls' interactions with peers and mentors in the…

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

Directory of Open Access Journals (Sweden)

SEANA Kelyn DAVIDSON

2014-10-01

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

Effects of Teacher-to-Student Relatedness on Adolescent Male Motivation in a Weight Training Class

Science.gov (United States)

Beddoes, Zack; Prusak, Keven; Barney, David; Wilkinson, Carol

2016-01-01

The purpose of this study was to determine if the motivational profiles of male junior high weight training students differ across levels of teacher-to-student relatedness. One hundred and sixty six students participated in one of two units of instruction. Contextual motivation was measured using the Sport Motivation Scale II-Physical Education…

Measuring autonomy, competence and relatedness of users needs ...

African Journals Online (AJOL)

There is a dearth of literature on users‟ need satisfaction from the psychological (mental and emotional) aspects of the variable as it affects usage of reference sources and services hence this study to measure autonomy, competence and relatedness of users needs‟ satisfaction on use of reference sources and services ...

Host and Symbiont Jointly Control Gut Microbiota during Complete Metamorphosis

Science.gov (United States)

Johnston, Paul R.; Rolff, Jens

2015-01-01

Holometabolous insects undergo a radical anatomical re-organisation during metamorphosis. This poses a developmental challenge: the host must replace the larval gut but at the same time retain symbiotic gut microbes and avoid infection by opportunistic pathogens. By manipulating host immunity and bacterial competitive ability, we study how the host Galleria mellonella and the symbiotic bacterium Enterococcus mundtii interact to manage the composition of the microbiota during metamorphosis. Disenabling one or both symbiotic partners alters the composition of the gut microbiota, which incurs fitness costs: adult hosts with a gut microbiota dominated by pathogens such as Serratia and Staphylococcus die early. Our results reveal an interaction that guarantees the safe passage of the symbiont through metamorphosis and benefits the resulting adult host. Host-symbiont “conspiracies” as described here are almost certainly widespread in holometobolous insects including many disease vectors. PMID:26544881

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

Science.gov (United States)

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

2018-03-01

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

Understanding nutrient exchange between Azolla and its symbiont, Nostoc

OpenAIRE

Eily, Ariana

2017-01-01

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

Relatedness as driver of regional diversification : a research agenda

NARCIS (Netherlands)

Boschma, Ron

2017-01-01

Relatedness as driver of regional diversification: a research agenda. Regional Studies. The regional diversification literature claims that regions diversify in new activities related to their existing activities from which new activities draw on and combine local capabilities. The paper offers a

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

Science.gov (United States)

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

2016-06-01

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

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

DEFF Research Database (Denmark)

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

2010-01-01

grown on the low nutrient diet. Thus, the Verminephrobacter nephridial symbionts do have a beneficial effect on their earthworm host. Cocoons with and without symbionts did not significantly differ in total organic carbon (TOC), total nitrogen (TN), or total hydrolysable amino acid (THAA) content, which...

Symbiont recognition of mutualistic bacteria by Acromyrmex leaf-cutting ants

DEFF Research Database (Denmark)

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

2007-01-01

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

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.

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

Science.gov (United States)

Chen, Xiaorui; Hitchings, Matthew D.; Mendoza, José E.; Balanza, Virginia; Facey, Paul D.; Dyson, Paul J.; Bielza, Pablo; Del Sol, Ricardo

2017-01-01

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. PMID:29067021

Growth tradeoffs associated with thermotolerant symbionts in the coral Pocillopora damicornis are lost in warmer oceans

Science.gov (United States)

Cunning, R.; Gillette, P.; Capo, T.; Galvez, K.; Baker, A. C.

2015-03-01

The growth and survival of reef corals are influenced by their symbiotic algal partners ( Symbiodinium spp.), which may be flexible in space and time. Tradeoffs among partnerships exist such that corals with thermotolerant symbionts (e.g., clade D) resist bleaching but grow more slowly, making the long-term ecosystem-level impacts of different host-symbiont associations uncertain. However, much of this uncertainty is due to limited data regarding these tradeoffs and particularly how they are mediated by the environment. To address this knowledge gap, we measured growth and survival of Pocillopora damicornis with thermally sensitive (clade C) or tolerant (clade D) symbionts at three temperatures over 18-55 weeks. Warming reduced coral growth overall, but altered the tradeoffs associated with symbiont type. While clade D corals grew 35-40 % slower than clade C corals at cooler temperatures (26 °C), warming of 1.5-3 °C reduced and eliminated this growth disadvantage. These results suggest that although warmer oceans will negatively impact corals, clade D may enhance survival at no cost to growth relative to clade C. Understanding these genotype-environment interactions can help improve modeling efforts and conservation strategies for reefs under global climate change.

Rickettsia ‘In’ and ‘Out’: Two Different Localization Patterns of a Bacterial Symbiont in the Same Insect Species

Science.gov (United States)

Caspi-Fluger, Ayelet; Inbar, Moshe; Mozes-Daube, Netta; Mouton, Laurence; Hunter, Martha S.; Zchori-Fein, Einat

2011-01-01

Intracellular symbionts of arthropods have diverse influences on their hosts, and their functions generally appear to be associated with their localization within the host. The effect of localization pattern on the role of a particular symbiont cannot normally be tested since the localization pattern within hosts is generally invariant. However, in Israel, the secondary symbiont Rickettsia is unusual in that it presents two distinct localization patterns throughout development and adulthood in its whitefly host, Bemisia tabaci (B biotype). In the “scattered” pattern, Rickettsia is localized throughout the whitefly hemocoel, excluding the bacteriocytes, where the obligate symbiont Portiera aleyrodidarum and some other secondary symbionts are housed. In the “confined” pattern, Rickettsia is restricted to the bacteriocytes. We examined the effects of these patterns on Rickettsia densities, association with other symbionts (Portiera and Hamiltonella defensa inside the bacteriocytes) and on the potential for horizontal transmission to the parasitoid wasp, Eretmocerus mundus, while the wasp larvae are developing within the whitefly nymph. Sequences of four Rickettsia genes were found to be identical for both localization patterns, suggesting that they are closely related strains. However, real-time PCR analysis showed very different dynamics for the two localization types. On the first day post-adult emergence, Rickettsia densities were 21 times higher in the “confined” pattern vs. “scattered” pattern whiteflies. During adulthood, Rickettsia increased in density in the “scattered” pattern whiteflies until it reached the “confined” pattern Rickettsia density on day 21. No correlation between Rickettsia densities and Hamiltonella or Portiera densities were found for either localization pattern. Using FISH technique, we found Rickettsia in the gut of the parasitoid wasps only when they developed on whiteflies with the “scattered” pattern. The

Carbon translocation from symbiont to host depends on irradiance and food availability in the tropical coral Stylophora pistillata

Science.gov (United States)

Tremblay, P.; Grover, R.; Maguer, J. F.; Hoogenboom, M.; Ferrier-Pagès, C.

2014-03-01

Reef-building corals live in symbiosis with dinoflagellates that translocate a large proportion of their photosynthetically fixed carbon compounds to their coral host for its own metabolism. The carbon budget and translocation rate, however, vary depending on environmental conditions, coral host species, and symbiont clade. To quantify variability in carbon translocation in response to environmental conditions, this study assessed the effect of two different irradiance levels (120 and 250 μmol photons m-2 s-1) and feeding regimes (fed with Artemia salina nauplii and unfed) on the carbon budget of the tropical coral Stylophora pistillata. For this purpose, H13CO3 --enriched seawater was used to trace the conversion of photosynthetic carbon into symbiont and coral biomass and excrete particulate organic carbon. Results showed that carbon translocation (ca. 78 %) and utilization were similar under both irradiance levels for unfed colonies. In contrast, carbon utilization by fed colonies was dependent on the growth irradiance. Under low irradiance, heterotrophy was accompanied by lower carbon translocation (71 %), higher host and symbiont biomass, and higher calcification rates. Under high irradiance, heterotrophy was accompanied by higher rates of photosynthesis, respiration, and carbon translocation (90 %) as well as higher host biomass. Hence, levels of resource sharing within coral-dinoflagellate symbioses depend critically on environmental conditions.

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

Directory of Open Access Journals (Sweden)

Sofya K. Garushyants

2018-04-01

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

Social insect symbionts: evolution in homeostatic fortresses

DEFF Research Database (Denmark)

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

2008-01-01

The massive environmentally buffered nests of some social insects can contain millions of individuals and a wide variety of parasites, commensals and mutualists. We suggest that the ways in which these homeostatic fortress environments affect the evolution of social insect symbionts are relevant...... in these nests. We hypothesize that biodiversity gradients in these hotspots might be less affected by abiotic latitudinal clines than gradients in neighboring 'control' habitats. We suggest several research lines to test these ideas....

The Mediating Role of Autonomy and Relatedness on Maternal and Child Outcomes.

Science.gov (United States)

Guo, Xiamei; Slesnick, Natasha

2018-02-01

The current study examined the mediating role of both mother and child interactive behaviors, which granted or undermined autonomy and relatedness, on the bidirectional and longitudinal association between maternal depressive symptoms and child internalizing behaviors, as well as the association between maternal substance use and child externalizing behaviors. Child's sex and mother's drug of choice were explored as potential moderators of the mediation relationship. Data were collected from 183 dyads including treatment-seeking substance using mothers and their children (95 males, aged between 8 and 16 years old). Structural equation modeling analysis showed girls' internalizing and externalizing behaviors at the 3-month follow-up were negatively associated with the same behaviors at the 12-month follow-up through increased relatedness undermining behaviors from their mothers at the 6-month follow-up. Among mothers with opioids as their drug of choice (DOC), children's externalizing behaviors at the 3-month follow-up were positively associated with mothers' substance use at the 12-month follow-up through the elevated levels of mothers' relatedness undermining behaviors at the 6-month follow-up. Among mothers with alcohol as their DOC, maternal depressive symptoms at the 3-month follow-up were positively related to children's internalizing behaviors at the 12-month follow-up through reduced relatedness undermining behaviors exhibited by mothers at the 6-month follow-up. To our knowledge, this is one of the first studies to attempt to unravel these longitudinal and bidirectional influences as well as the moderated mediation pathways among families with a substance using mothers.

Consumers’ perception of relatedness in mental representations of products

NARCIS (Netherlands)

Gattol, V.

2013-01-01

The work in this thesis investigates relatedness (as perceived by consumers) in mental representations of products. Just as other objects that are part of the physical world, products are represented in consumers’ minds in the form of concepts. Concepts hold consumers’ knowledge about a product.

29 CFR 1904.5 - Determination of work-relatedness.

Science.gov (United States)

2010-07-01

... poisoning from food supplied by the employer, the case would be considered work-related. (v) The injury or... hotel, motel, or into an other temporary residence, he or she establishes a “home away from home.” You... temporary residence for their work-relatedness in the same manner as you evaluate the activities of a non...

Productivity links morphology, symbiont specificity and bleaching in the evolution of Caribbean octocoral symbioses.

Science.gov (United States)

Baker, David M; Freeman, Christopher J; Knowlton, Nancy; Thacker, Robert W; Kim, Kiho; Fogel, Marilyn L

2015-12-01

Many cnidarians host endosymbiotic dinoflagellates from the genus Symbiodinium. It is generally assumed that the symbiosis is mutualistic, where the host benefits from symbiont photosynthesis while providing protection and photosynthetic substrates. Diverse assemblages of symbiotic gorgonian octocorals can be found in hard bottom communities throughout the Caribbean. While current research has focused on the phylo- and population genetics of gorgonian symbiont types and their photo-physiology, relatively less work has focused on biogeochemical benefits conferred to the host and how these benefits vary across host species. Here we examine this symbiosis among 11 gorgonian species collected in Bocas del Toro, Panama. By coupling light and dark bottle incubations (P/R) with (13)C-bicarbonate tracers, we quantified the link between holobiont oxygen metabolism with carbon assimilation and translocation from symbiont to host. Our data show that P/R varied among species, and was correlated with colony morphology and polyp size. Sea fans and sea plumes were net autotrophs (P/R>1.5), while nine species of sea rods were net heterotrophs with most below compensation (P/R<1.0). (13)C assimilation corroborated the P/R results, and maximum δ(13)Chost values were strongly correlated with polyp size, indicating higher productivity by colonies with high polyp SA:V. A survey of gorgonian-Symbiodinium associations revealed that productive species maintain specialized, obligate symbioses and are more resistant to coral bleaching, whereas generalist and facultative associations are common among sea rods that have higher bleaching sensitivities. Overall, productivity and polyp size had strong phylogenetic signals with carbon fixation and polyp size showing evidence of trait covariance.

Gender differences in the family-relatedness of relocation decisions

NARCIS (Netherlands)

Ullrich, J.; Pluut, Helen; Büttgen, M.

2015-01-01

Using a dyadic study design, the present study draws on research into the family-relatedness of work decisions to examine the impact of the spouse's characteristics on an employee's willingness to engage in job-related relocation. With a sample of 1234 employees, the results show that spousal

Potential costs of acclimatization to a warmer climate: growth of a reef coral with heat tolerant vs. sensitive symbiont types.

Directory of Open Access Journals (Sweden)

Alison Jones

Full Text Available One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 or thermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type D zooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change.

Potential Costs of Acclimatization to a Warmer Climate: Growth of a Reef Coral with Heat Tolerant vs. Sensitive Symbiont Types

Science.gov (United States)

Jones, Alison; Berkelmans, Ray

2010-01-01

One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae) genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 or thermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type D zooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change. PMID:20454653

Potential costs of acclimatization to a warmer climate: growth of a reef coral with heat tolerant vs. sensitive symbiont types.

Science.gov (United States)

Jones, Alison; Berkelmans, Ray

2010-05-03

One of the principle ways in which reef building corals are likely to cope with a warmer climate is by changing to more thermally tolerant endosymbiotic algae (zooxanthellae) genotypes. It is highly likely that hosting a more heat-tolerant algal genotype will be accompanied by tradeoffs in the physiology of the coral. To better understand one of these tradeoffs, growth was investigated in the Indo-Pacific reef-building coral Acropora millepora in both the laboratory and the field. In the Keppel Islands in the southern Great Barrier Reef this species naturally harbors nrDNA ITS1 thermally sensitive type C2 or thermally tolerant type D zooxanthellae of the genus Symbiodinium and can change dominant type following bleaching. We show that under controlled conditions, corals with type D symbionts grow 29% slower than those with type C2 symbionts. In the field, type D colonies grew 38% slower than C2 colonies. These results demonstrate the magnitude of trade-offs likely to be experienced by this species as they acclimatize to warmer conditions by changing to more thermally tolerant type D zooxanthellae. Irrespective of symbiont genotype, corals were affected to an even greater degree by the stress of a bleaching event which reduced growth by more than 50% for up to 18 months compared to pre-bleaching rates. The processes of symbiont change and acute thermal stress are likely to act in concert on coral growth as reefs acclimatize to more stressful warmer conditions, further compromising their regeneration capacity following climate change.

A Novel Extracellular Gut Symbiont in the Marine Worm Priapulus caudatus (Priapulida) Reveals an Alphaproteobacterial Symbiont Clade of the Ecdysozoa

OpenAIRE

Kroer, Paul; Kjeldsen, Kasper U.; Nyengaard, Jens R.; Schramm, Andreas; Funch, Peter

2016-01-01

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

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

Science.gov (United States)

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

2015-09-01

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

Genetic Diversity and Phylogenetic Relationships of Coevolving Symbiont-Harboring Insect Trypanosomatids, and Their Neotropical Dispersal by Invader African Blowflies (Calliphoridae

Directory of Open Access Journals (Sweden)

Tarcilla C. Borghesan

2018-02-01

Full Text Available This study is about the inter- and intra-specific genetic diversity of trypanosomatids of the genus Angomonas, and their association with Calliphoridae (blowflies in Neotropical and Afrotropical regions. Microscopic examination of 3,900 flies of various families, mostly Calliphoridae, revealed that 31% of them harbored trypanosomatids. Small subunit rRNA (SSU rRNA barcoding showed that Angomonas predominated (46% over the other common trypanosomatids of blowflies of genera Herpetomonas and Wallacemonas. Among Angomonas spp., A. deanei was much more common than the two-other species, A. desouzai and A. ambiguus. Phylogenetic analyses based on SSU rRNA, glycosomal glyceraldehyde-3-phosphate dehydrogenase (gGAPDH and internal transcribed spacer rDNA (ITS rDNA sequences revealed a marked genetic diversity within A. deanei, which comprised four infraspecific genotypes (Dea1–Dea4, and four corresponding symbiont genotypes (Kcr1–Kcr4. Host and symbiont phylogenies were highly congruent corroborating their co-divergence, consistent with host-symbiont interdependent metabolism and symbiont reduced genomes shaped by a long coevolutionary history. We compared the diversity of Angomonas/symbionts from three genera of blowflies, Lucilia, Chrysomya and Cochliomyia. A. deanei, A. desouzai, and A. ambiguus were found in the three genera of blowflies in South America. In Africa, A. deanei and A. ambiguus were identified in Chrysomya. The absence of A. desouzai in Africa and its presence in Neotropical Cochliomyia and Lucilia suggests parasite spillback of A. desouzai into Chrysomya, which was most likely introduced four decades ago from Africa into the Neotropic. The absence of correlation between parasite diversity and geographic and genetic distances, with identical genotypes of A. deanei found in the Neotropic and Afrotropic, is consistent with disjunct distribution due to the recent human-mediated transoceanic dispersal of Angomonas by Chrysomya. This

Longitudinal Associations of Autonomy, Relatedness, and Competence with the Well-being of Nursing Home Residents.

Science.gov (United States)

Kloos, Noortje; Trompetter, Hester R; Bohlmeijer, Ernst T; Westerhof, Gerben J

2018-02-24

As proposed by the self-determination theory, satisfying nursing home residents' needs for autonomy, relatedness, and competence may improve their well-being. This is the first study to test the longitudinal relations of the satisfaction of these three basic psychological needs to the subjective well-being of nursing home residents and to determine whether a balance among the satisfaction of the three needs is important for well-being. Participants in this longitudinal survey study included 128 physically frail residents (mean age 85 years) at four Dutch nursing homes. Satisfaction of the three basic psychological needs was measured at baseline, and depressive feelings and life satisfaction 5-8 months later. Absolute differences between the three basic need satisfaction scores were summed to create a score of need satisfaction balance. All three needs were related to both well-being measures over time, although autonomy had the strongest relationships. Only autonomy and competence were uniquely associated with depressive feelings, and only autonomy was uniquely associated with life satisfaction. The need satisfaction balance score was related to well-being independent of the autonomy and relatedness scores. These results confirm that all three basic psychological needs are important for nursing home residents' well-being, with autonomy having the strongest and most consistent relationship to their well-being. Additionally, high satisfaction of one need does not compensate for low satisfaction of another. Supporting residents' needs for autonomy, relatedness, and competence should, therefore, have a central role in nursing home culture-change interventions.

Multi-omics analysis of thermal stress response in a zooxanthellate cnidarian reveals the importance of associating with thermotolerant symbionts

KAUST Repository

Cziesielski, Maha J.

2018-04-18

Corals and their endosymbiotic dinoflagellates of the genus Symbiodinium have a fragile relationship that breaks down under heat stress, an event known as bleaching. However, many coral species have adapted to high temperature environments such as the Red Sea (RS). To investigate mechanisms underlying temperature adaptation in zooxanthellate cnidarians we compared transcriptome- and proteome-wide heat stress response (24 h at 32°C) of three strains of the model organism Aiptasia pallida from regions with differing temperature profiles; North Carolina (CC7), Hawaii (H2) and the RS. Correlations between transcript and protein levels were generally low but inter-strain comparisons highlighted a common core cnidarian response to heat stress, including protein folding and oxidative stress pathways. RS anemones showed the strongest increase in antioxidant gene expression and exhibited significantly lower reactive oxygen species (ROS) levels in hospite However, comparisons of antioxidant gene and protein expression between strains did not show strong differences, indicating similar antioxidant capacity across the strains. Subsequent analysis of ROS production in isolated symbionts confirmed that the observed differences of ROS levels in hospite were symbiont-driven. Our findings indicate that RS anemones do not show increased antioxidant capacity but may have adapted to higher temperatures through association with more thermally tolerant symbionts.

Multi-omics analysis of thermal stress response in a zooxanthellate cnidarian reveals the importance of associating with thermotolerant symbionts

KAUST Repository

Cziesielski, Maha J.; Liew, Yi Jin; Cui, Guoxin; Schmidt-Roach, Sebastian; Campana, Sara; Marondedze, Claudius; Aranda, Manuel

2018-01-01

Corals and their endosymbiotic dinoflagellates of the genus Symbiodinium have a fragile relationship that breaks down under heat stress, an event known as bleaching. However, many coral species have adapted to high temperature environments such as the Red Sea (RS). To investigate mechanisms underlying temperature adaptation in zooxanthellate cnidarians we compared transcriptome- and proteome-wide heat stress response (24 h at 32°C) of three strains of the model organism Aiptasia pallida from regions with differing temperature profiles; North Carolina (CC7), Hawaii (H2) and the RS. Correlations between transcript and protein levels were generally low but inter-strain comparisons highlighted a common core cnidarian response to heat stress, including protein folding and oxidative stress pathways. RS anemones showed the strongest increase in antioxidant gene expression and exhibited significantly lower reactive oxygen species (ROS) levels in hospite However, comparisons of antioxidant gene and protein expression between strains did not show strong differences, indicating similar antioxidant capacity across the strains. Subsequent analysis of ROS production in isolated symbionts confirmed that the observed differences of ROS levels in hospite were symbiont-driven. Our findings indicate that RS anemones do not show increased antioxidant capacity but may have adapted to higher temperatures through association with more thermally tolerant symbionts.

Chemosynthetic symbionts of marine invertebrate animals are capable of nitrogen fixation

NARCIS (Netherlands)

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

2016-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

Coleman-Derr, Devin [USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States); Tringe, Susannah G. [USDOE Joint Genome Institute (JGI), Walnut Creek, CA (United States)

2014-06-06

The exponential growth in world population is feeding a steadily increasing global need for arable farmland, a resource that is already in high demand. This trend has led to increased farming on subprime arid and semi-arid lands, where limited availability of water and a host of environmental stresses often severely reduce crop productivity. The conventional approach to mitigating the abiotic stresses associated with arid climes is to breed for stress-tolerant cultivars, a time and labor intensive venture that often neglects the complex ecological context of the soil environment in which the crop is grown. In recent years, studies have attempted to identify microbial symbionts capable of conferring the same stress-tolerance to their plant hosts, and new developments in genomic technologies have greatly facilitated such research. Here in this paper, we highlight many of the advantages of these symbiont-based approaches and argue in favor of the broader recognition of crop species as ecological niches for a diverse community of microorganisms that function in concert with their plant hosts and each other to thrive under fluctuating environmental conditions

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

Directory of Open Access Journals (Sweden)

Devin eColeman-Derr

2014-06-01

Full Text Available The exponential growth in world population is feeding a steadily increasing global need for arable farmland, a resource that is already in high demand. This trend has led to increased farming on subprime arid and semi-arid lands, where limited availability of water and a host of environmental stresses often severely reduce crop productivity. The conventional approach to mitigating the abiotic stresses associated with arid climes is to breed for stress-tolerant cultivars, a time and labor intensive venture that often neglects the complex ecological context of the soil environment in which the crop is grown. In recent years, studies have attempted to identify microbial symbionts capable of conferring the same stress-tolerance to their plant hosts, and new developments in genomic technologies have greatly facilitated such research. Here, we highlight many of the advantages of these symbiont-based approaches and argue in favor of the broader recognition of crop species as ecological niches for a diverse community of microorganisms that function in concert with their plant hosts and each other to thrive under fluctuating environmental conditions.

Double-digest RAD sequencing outperforms microsatellite loci at assigning paternity and estimating relatedness: A proof of concept in a highly promiscuous bird.

Science.gov (United States)

Thrasher, Derrick J; Butcher, Bronwyn G; Campagna, Leonardo; Webster, Michael S; Lovette, Irby J

2018-02-17

Information on genetic relationships among individuals is essential to many studies of the behaviour and ecology of wild organisms. Parentage and relatedness assays based on large numbers of single nucleotide polymorphism (SNP) loci hold substantial advantages over the microsatellite markers traditionally used for these purposes. We present a double-digest restriction site-associated DNA sequencing (ddRAD-seq) analysis pipeline that, as such, simultaneously achieves the SNP discovery and genotyping steps and which is optimized to return a statistically powerful set of SNP markers (typically 150-600 after stringent filtering) from large numbers of individuals (up to 240 per run). We explore the trade-offs inherent in this approach through a set of experiments in a species with a complex social system, the variegated fairy-wren (Malurus lamberti) and further validate it in a phylogenetically broad set of other bird species. Through direct comparisons with a parallel data set from a robust panel of highly variable microsatellite markers, we show that this ddRAD-seq approach results in substantially improved power to discriminate among potential relatives and considerably more precise estimates of relatedness coefficients. The pipeline is designed to be universally applicable to all bird species (and with minor modifications to many other taxa), to be cost- and time-efficient, and to be replicable across independent runs such that genotype data from different study periods can be combined and analysed as field samples are accumulated. © 2018 John Wiley & Sons Ltd.

Definition and structure of body-relatedness from the perspective of patients with severe somatoform disorder and their therapists.

Science.gov (United States)

Kalisvaart, Hanneke; van Broeckhuysen, Saskia; Bühring, Martina; Kool, Marianne B; van Dulmen, Sandra; Geenen, Rinie

2012-01-01

How a patient is connected with one's body is core to rehabilitation of somatoform disorder but a common model to describe body-relatedness is missing. The aim of our study was to investigate the components and hierarchical structure of body-relatedness as perceived by patients with severe somatoform disorder and their therapists. Interviews with patients and therapists yielded statements about components of body-relatedness. Patients and therapists individually sorted these statements according to similarity. Hierarchical cluster analysis was applied to these sortings. Analysis of variance was used to compare the perceived importance of the statements between patients and therapists. The hierarchical structure included 71 characteristics of body-relatedness. It consisted of three levels with eight clusters at the lowest level: 1) understanding, 2) acceptance, 3) adjustment, 4) respect for the body, 5) regulation, 6) confidence, 7) self-esteem, and 8) autonomy. The cluster 'understanding' was considered most important by patients and therapists. Patients valued 'regulating the body' more than therapists. According to patients with somatoform disorders and their therapists, body-relatedness includes awareness of the body and self by understanding, accepting and adjusting to bodily signals, by respecting and regulating the body, by confiding and esteeming oneself and by being autonomous. This definition and structure of body-relatedness may help professionals to improve interdisciplinary communication, assessment, and treatment, and it may help patients to better understand their symptoms and treatment. (German language abstract, Abstract S1; Spanish language abstract, Abstract S2).

Microarray-based whole-genome hybridization as a tool for determining procaryotic species relatedness

Energy Technology Data Exchange (ETDEWEB)

Wu, L.; Liu, X.; Fields, M.W.; Thompson, D.K.; Bagwell, C.E.; Tiedje, J. M.; Hazen, T.C.; Zhou, J.

2008-01-15

The definition and delineation of microbial species are of great importance and challenge due to the extent of evolution and diversity. Whole-genome DNA-DNA hybridization is the cornerstone for defining procaryotic species relatedness, but obtaining pairwise DNA-DNA reassociation values for a comprehensive phylogenetic analysis of procaryotes is tedious and time consuming. A previously described microarray format containing whole-genomic DNA (the community genome array or CGA) was rigorously evaluated as a high-throughput alternative to the traditional DNA-DNA reassociation approach for delineating procaryotic species relationships. DNA similarities for multiple bacterial strains obtained with the CGA-based hybridization were comparable to those obtained with various traditional whole-genome hybridization methods (r=0.87, P<0.01). Significant linear relationships were also observed between the CGA-based genome similarities and those derived from small subunit (SSU) rRNA gene sequences (r=0.79, P<0.0001), gyrB sequences (r=0.95, P<0.0001) or REP- and BOX-PCR fingerprinting profiles (r=0.82, P<0.0001). The CGA hybridization-revealed species relationships in several representative genera, including Pseudomonas, Azoarcus and Shewanella, were largely congruent with previous classifications based on various conventional whole-genome DNA-DNA reassociation, SSU rRNA and/or gyrB analyses. These results suggest that CGA-based DNA-DNA hybridization could serve as a powerful, high-throughput format for determining species relatedness among microorganisms.

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

Science.gov (United States)

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

Characterization and role of p53 family members in the symbiont-induced morphogenesis of the Euprymna scolopes light organ.

Science.gov (United States)

Goodson, Michael S; Crookes-Goodson, Wendy J; Kimbell, Jennifer R; McFall-Ngai, Margaret J

2006-08-01

Within hours of hatching, the squid Euprymna scolopes forms a specific light organ symbiosis with the marine luminous bacterium Vibrio fischeri. Interactions with the symbiont result in the loss of a complex ciliated epithelium dedicated to promoting colonization of host tissue, and some or all of this loss is due to widespread, symbiont-induced apoptosis. Members of the p53 family, including p53, p63, and p73, are conserved across broad phyletic lines and p63 is thought to be the ancestral gene. These proteins have been shown to induce apoptosis and developmental morphogenesis. In this study, we characterized p63-like transcripts from mRNA isolated from the symbiotic tissues of E. scolopes and described their role in symbiont-induced morphogenesis. Using degenerate RT-PCR and RACE PCR, we identified two p63-like transcripts encoding proteins of 431 and 567 amino acids. These transcripts shared identical nucleotides where they overlapped, suggesting that they are splice variants of the same gene. Immunocytochemistry and Western blots using an antibody specific for E. scolopes suggested that the p53 family members are activated in cells of the symbiont-harvesting structures of the symbiotic light organ. We propose that once the symbiosis is initiated, a symbiont-induced signal activates p53 family members, inducing apoptosis and developmental morphogenesis of the light organ.

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

Science.gov (United States)

Futahashi, Ryo; Tanaka, Kohjiro; Tanahashi, Masahiko; Nikoh, Naruo; Kikuchi, Yoshitomo; Lee, Bok Luel; Fukatsu, Takema

2013-01-01

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.

Complete Genome Sequence of the Human Gut Symbiont Roseburia hominis

DEFF Research Database (Denmark)

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

2015-01-01

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

Single-Cell Biomolecular Analysis of Coral Algal Symbionts Reveals Opposing Metabolic Responses to Heat Stress and Expulsion

Directory of Open Access Journals (Sweden)

Katherina Petrou

2018-03-01

Full Text Available The success of corals in nutrient poor environments is largely attributed to the symbiosis between the cnidarian host and its intracellular alga. Warm water anomalies have been shown to destabilize this symbiosis, yet detailed analysis of the effect of temperature and expulsion on cell-specific carbon and nutrient allocation in the symbiont is limited. Here, we exposed colonies of the hard coral Acropora millepora to heat stress and using synchrotron-based infrared microspectroscopy measured the biomolecular profiles of individual in hospite and expelled symbiont cells at an acute state of bleaching. Our results showed symbiont metabolic profiles to be remarkably distinct with heat stress and expulsion, where the two effectors elicited opposing metabolic adjustments independent of treatment or cell type. Elevated temperature resulted in biomolecular changes reflecting cellular stress, with relative increases in free amino acids and phosphorylation of molecules and a concomitant decline in protein content, suggesting protein modification and degradation. This contrasted with the metabolic profiles of expelled symbionts, which showed relative decreases in free amino acids and phosphorylated molecules, but increases in proteins and lipids, suggesting expulsion lessens the overall effect of heat stress on the metabolic signature of the algal symbionts. Interestingly, the combined effects of expulsion and thermal stress were additive, reducing the overall shifts in all biomolecules, with the notable exception of the significant accumulation of lipids and saturated fatty acids. This first use of a single-cell metabolomics approach on the coral symbiosis provides novel insight into coral bleaching and emphasizes the importance of a single-cell approach to demark the cell-to-cell variability in the physiology of coral cellular populations.

Comparative Profiling of coral symbiont communities from the Caribbean, Indo-Pacific, and Arabian Seas

KAUST Repository

Arif, Chatchanit

2014-12-01

Coral reef ecosystems are in rapid decline due to global and local anthropogenic factors. Being among the most diverse ecosystems on Earth, a loss will decrease species diversity, and remove food source for people along the coast. The coral together with its symbionts (i.e. Symbiodinium, bacteria, and other microorganisms) is called the ‘coral holobiont’. The coral host offers its associated symbionts suitable habitats and nutrients, while Symbiodinium and coral-associated bacteria provide the host with photosynthates and vital nutrients. Association of corals with certain types of Symbiodinium and bacteria confer coral stress tolerance, and lack or loss of these symbionts coincides with diseased or bleached corals. However, a detailed understanding of the coral holobiont diversity and structure in regard to diseases and health states or across global scales is missing. This dissertation addressed coral-associated symbiont diversity, specifically of Symbiodinium and bacteria, in various coral species from different geographic locations and different health states. The main aims were (1) to expand the scope of existing technologies, (2) to establish a standardized framework to facilitate comparison of symbiont assemblages over coral species and sites, (3) to assess Symbiodinium diversity in the Arabian Seas, and (4) to elucidate whether coral health states have conserved bacterial footprints. In summary, a next generation sequencing pipeline for Symbiodinium diversity typing of the ITS2 marker is developed and applied to describe Symbiodinium diversity in corals around the Arabian Peninsula. The data show that corals in the Arabian Seas are dominated by a single Symbiodinium type, but harbor a rich variety of types in low abundant. Further, association with different Symbiodinium types is structured according to geographic locations. In addition, the application of 16S rRNA gene microarrays to investigate how differences in microbiome structure relate to

Principals and Self-Determination Theory (SDT): What Trends Are Seen in Levels of Autonomy, Competence, and Relatedness?

Science.gov (United States)

Roundy-Harter, Anne

2010-01-01

This study builds upon Deci and Ryan's (1985) Self-Determination Theory (SDT) which states that humans must meet three basic psychological needs for optimal well-being: autonomy, competence, and relatedness. The purpose of this qualitative study was to explore trends in principals' experiences in the areas of autonomy, competence, and relatedness.…

Definition and structure of body-relatedness from the perspective of patients with severe somatoform disorder and their therapists.

Directory of Open Access Journals (Sweden)

Hanneke Kalisvaart

Full Text Available BACKGROUND: How a patient is connected with one's body is core to rehabilitation of somatoform disorder but a common model to describe body-relatedness is missing. The aim of our study was to investigate the components and hierarchical structure of body-relatedness as perceived by patients with severe somatoform disorder and their therapists. METHODS: Interviews with patients and therapists yielded statements about components of body-relatedness. Patients and therapists individually sorted these statements according to similarity. Hierarchical cluster analysis was applied to these sortings. Analysis of variance was used to compare the perceived importance of the statements between patients and therapists. RESULTS: The hierarchical structure included 71 characteristics of body-relatedness. It consisted of three levels with eight clusters at the lowest level: 1 understanding, 2 acceptance, 3 adjustment, 4 respect for the body, 5 regulation, 6 confidence, 7 self-esteem, and 8 autonomy. The cluster 'understanding' was considered most important by patients and therapists. Patients valued 'regulating the body' more than therapists. CONCLUSION: According to patients with somatoform disorders and their therapists, body-relatedness includes awareness of the body and self by understanding, accepting and adjusting to bodily signals, by respecting and regulating the body, by confiding and esteeming oneself and by being autonomous. This definition and structure of body-relatedness may help professionals to improve interdisciplinary communication, assessment, and treatment, and it may help patients to better understand their symptoms and treatment. (German language abstract, Abstract S1; Spanish language abstract, Abstract S2.

Host immunostimulation and substrate utilization of the gut symbiont Akkermansia muciniphila

NARCIS (Netherlands)

Ottman, N.A.

2015-01-01

Host immunostimulation and substrate utilization of the gut symbiont Akkermansia muciniphila

Noora A. Ottman

The human gastrointestinal tract is colonized by a complex community of micro-organisms, the gut microbiota. The majority of these

A New Niche for Vibrio logei, the Predominant Light Organ Symbiont of Squids in the Genus Sepiola

OpenAIRE

Fidopiastis, Pat M.; von Boletzky, Sigurd; Ruby, Edward G.

1998-01-01

Two genera of sepiolid squids—Euprymna, found primarily in shallow, coastal waters of Hawaii and the Western Pacific, and Sepiola, the deeper-, colder-water-dwelling Mediterranean and Atlantic squids—are known to recruit luminous bacteria into light organ symbioses. The light organ symbiont of Euprymna spp. is Vibrio fischeri, but until now, the light organ symbionts of Sepiola spp. have remained inadequately identified. We used a combination of molecular and physiological characteristics to ...

Dark production of extracellular superoxide by the coral Porites astreoides and representative symbionts

Directory of Open Access Journals (Sweden)

Tong Zhang

2016-11-01

Full Text Available The reactive oxygen species (ROS superoxide has been implicated in both beneficial and detrimental processes in coral biology, ranging from pathogenic disease resistance to coral bleaching. Despite the critical role of ROS in coral health, there is a distinct lack of ROS measurements and thus an incomplete understanding of underpinning ROS sources and production mechanisms within coral systems. Here, we quantified in situ extracellular superoxide concentrations at the surfaces of aquaria-hosted Porites astreoides during a diel cycle. High concentrations of superoxide (~10’s of nM were present at coral surfaces, and these levels did not change significantly as a function of time of day. These results indicate that the coral holobiont produces extracellular superoxide in the dark, independent of photosynthesis. As a short-lived anion at physiological pH, superoxide has a limited ability to cross intact biological membranes. Further, removing surface mucus layers from the P. astreoides colonies did not impact external superoxide concentrations. We therefore attribute external superoxide derived from the coral holobiont under these conditions to the activity of the coral host epithelium, rather than mucus-derived epibionts or internal sources such as endosymbionts (e.g., Symbiodinium. However, endosymbionts likely contribute to internal ROS levels via extracellular superoxide production. Indeed, common coral symbionts, including multiple strains of Symbiodinium (clades A to D and the bacterium Endozoicomonas montiporae LMG 24815, produced extracellular superoxide in the dark and at low light levels. Further, representative P. astreoides symbionts, Symbiodinium CCMP2456 (clade A and E. montiporae, produced similar concentrations of superoxide alone and in combination with each other, in the dark and low light, and regardless of time of day. Overall, these results indicate that healthy, non-stressed P. astreoides and representative symbionts produce

Definition and structure of body-relatedness from the perspective of patients with severe somatoform disorder and their therapists.

NARCIS (Netherlands)

Kalisvaart, H.; Broeckhuysen, S. van; Bühring, M.; Kool, M.B.; Dulmen, S. van; Geenen, R.

2012-01-01

Background: How a patient is connected with one's body is core to rehabilitation of somatoform disorder but a common model to describe body-relatedness is missing. The aim of our study was to investigate the components and hierarchical structure of body-relatedness as perceived by patients with

Discrepancies in Autonomy and Relatedness Promoting Behaviors of Substance Using Mothers and Their Children: The Effects of a Family Systems Intervention.

Science.gov (United States)

Zhang, Jing; Slesnick, Natasha

2017-03-01

Parents' and children's autonomy and relatedness behaviors are associated with a wide range of child outcomes. Yet, little is known about how parents and children's autonomy and relatedness behaviors jointly influence child outcomes. The current study captured this joint influence by exploring the longitudinal trajectory of mother-child discrepancies in autonomy and relatedness behaviors and its association with child problem behaviors. The effects of a family systems intervention on the trajectory of mother-child discrepancies were also examined. The sample included 183 substance using mothers and their children (M age = 11.54 years, SD = 2.55, range 8-16; 48 % females). Both the mother and child completed an assessment at baseline, 6- and 18-month post-baseline. A person-centered analysis identified subgroups varying in mother-child discrepancy patterns in their autonomy and relatedness behaviors. The results also showed that participation in the family systems therapy was associated with decreased mother-child discrepancies, and also a synchronous increase in mother's and child's autonomy and relatedness. Additionally, increased mother-child discrepancies and mother-child dyads showing no change in autonomy and relatedness was associated with higher levels of children's problem behaviors. The findings reveal a dynamic process of mother-child discrepancies in autonomy and relatedness behaviors related to child outcomes. The findings also support the effectiveness of the family systems therapy, and highlight the importance of understanding the complexities in family interactions when explaining children's problem behaviors.

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

Science.gov (United States)

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

2017-03-01

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

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

Science.gov (United States)

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

2017-03-01

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

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

Directory of Open Access Journals (Sweden)

Karina van der Heijden

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

A new concept of relatedness and its significance to the theory of social evolution

Directory of Open Access Journals (Sweden)

M.S. Drummond

2000-03-01

Full Text Available Data on primitively social groups of Hymenoptera have been somewhat contradictory with respect to kin recognition, degree of relatedness and social evolution. This study presents a new concept of "relatedness coefficient". Called "aggregated relatedness", the hypothesis here introduced proposes that genes shared by any two individuals affect formation of family units to an extent dependent on their frequency and manner of dispersion in neighboring populations.Dados de campo de espécies de Hymenoptera primitivamente sociais têm se mostrado contraditórios quanto ao papel do reconhecimento de parentes e do grau de parentesco na evolução social. Nesse trabalho um novo conceito de "coeficiente de parentesco" foi desenvolvido. Esta nova hipótese foi chamada de "parentesco agregado". Nesse conceito, genes compartilhados por dois indivíduos quaisquer têm importância significativa na formação das unidades familiares, dependendo de suas freqüências e da forma como estão distribuídos na população circunvizinha a esta unidade familiar.

Identification and characterization of bacterial symbionts in three species of filth fly parasitoids.

Science.gov (United States)

Betelman, Kfir; Caspi-Fluger, Ayelet; Shamir, Maayan; Chiel, Elad

2017-09-01

Facultative bacterial symbionts are widespread among insects and have diverse effects on their biology. Here, we focused on bacterial symbionts of three ecologically and economically important filth flies parasitoid species-Spalangia cameroni, Spalangia endius and Muscidifurax raptor. Both Spalangia species harbored a Sodalis bacterium that is closely related to Spalangia praecaptivus (a free-living bacterium) and to Sodalis symbionts of weevils. This is the only case of Sodalis infection in the important order Hymenoptera. We also found, for the first time in this parasitoid guild, a Rickettsia infecting the two Spalangia spp., albeit in much higher prevalence in S. cameroni. Molecular and phylogenetic analyses revealed that it is closely related to Rickettsia felis and other Rickettsia species from the 'transitional' group. All three parasitoid species harbored Wolbachia. Using multi-locus sequence typing, we found that M. raptor harbors a single Wolbachia strain whereas the Spalangia spp. have multiple strains. By controlled crossings, we found that Wolbachia infection in S. endius causes incomplete cytoplasmic incompatibility and increased longevity, thereby promoting Wolbachia's spread. In contrast, no effects of Wolbachia on the reproduction and longevity of M. raptor were found. This study underscores the diversity and nature of symbiotic interactions between microbes and insects. © FEMS 2017. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

In situ photobiology of corals over large depth ranges: A multivariate analysis on the roles of environment, host, and algal symbiont

NARCIS (Netherlands)

Frade, P.R.; Bongaerts, P.; Winkelhagen, A.J.S.; Tonk, L.; Bak, R.P.M.

2008-01-01

We applied a multivariate analysis to investigate the roles of host and symbiont on the in situ physiological response of genus Madracis holobionts towards light. Across a large depth gradient (5-40 m) and for four Madracis species and three symbiont genotypes, we assessed several variables by

Prediction of social structure and genetic relatedness in colonies of the facultative polygynous stingless bee Melipona bicolor (Hymenoptera, Apidae).

Science.gov (United States)

Dos Reis, Evelyze Pinheiro; de Oliveira Campos, Lucio Antonio; Tavares, Mara Garcia

2011-04-01

Stingless bee colonies typically consist of one single-mated mother queen and her worker offspring. The stingless bee Melipona bicolor (Hymenoptera: Apidae) shows facultative polygyny, which makes this species particularly suitable for testing theoretical expectations concerning social behavior. In this study, we investigated the social structure and genetic relatedness among workers from eight natural and six manipulated colonies of M. bicolor over a period of one year. The populations of M. bicolor contained monogynous and polygynous colonies. The estimated genetic relatedness among workers from monogynous and polygynous colonies was 0.75 ± 0.12 and 0.53 ± 0.16 (mean ± SEM), respectively. Although the parental genotypes had significant effects on genetic relatedness in monogynous and polygynous colonies, polygyny markedly decreased the relatedness among nestmate workers. Our findings also demonstrate that polygyny in M. bicolor may arise from the adoption of related or unrelated queens.

Prediction of social structure and genetic relatedness in colonies of the facultative polygynous stingless bee Melipona bicolor (Hymenoptera, Apidae

Directory of Open Access Journals (Sweden)

Evelyze Pinheiro dos Reis

2011-01-01

Full Text Available Stingless bee colonies typically consist of one single-mated mother queen and her worker offspring. The stingless bee Melipona bicolor (Hymenoptera: Apidae shows facultative polygyny, which makes this species particularly suitable for testing theoretical expectations concerning social behavior. In this study, we investigated the social structure and genetic relatedness among workers from eight natural and six manipulated colonies of M. bicolor over a period of one year. The populations of M. bicolor contained monogynous and polygynous colonies. The estimated genetic relatedness among workers from monogynous and polygynous colonies was 0.75 ± 0.12 and 0.53 ± 0.16 (mean ± SEM, respectively. Although the parental genotypes had significant effects on genetic relatedness in monogynous and polygynous colonies, polygyny markedly decreased the relatedness among nestmate workers. Our findings also demonstrate that polygyny in M. bicolor may arise from the adoption of related or unrelated queens.

Riptortus pedestris and Burkholderia symbiont: an ideal model system for insect-microbe symbiotic associations.

Science.gov (United States)

Takeshita, Kazutaka; Kikuchi, Yoshitomo

2017-04-01

A number of insects establish symbiotic associations with beneficial microorganisms in various manners. The bean bug Riptortus pedestris and allied stink bugs possess an environmentally acquired Burkholderia symbiont in their midgut crypts. Unlike other insect endosymbionts, the Burkholderia symbiont is easily culturable and genetically manipulatable outside the host. In conjunction with the experimental advantages of the host insect, the Riptortus-Burkholderia symbiosis is an ideal model system for elucidating the molecular bases underpinning insect-microbe symbioses, which opens a new window in the research field of insect symbiosis. This review summarizes current knowledge of this system and discusses future perspectives. Copyright © 2016 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Evidence of environmental and vertical transmission of Burkholderia symbionts in the oriental chinch bug, Cavelerius saccharivorus (Heteroptera: Blissidae).

Science.gov (United States)

Itoh, Hideomi; Aita, Manabu; Nagayama, Atsushi; Meng, Xian-Ying; Kamagata, Yoichi; Navarro, Ronald; Hori, Tomoyuki; Ohgiya, Satoru; Kikuchi, Yoshitomo

2014-10-01

The vertical transmission of symbiotic microorganisms is omnipresent in insects, while the evolutionary process remains totally unclear. The oriental chinch bug, Cavelerius saccharivorus (Heteroptera: Blissidae), is a serious sugarcane pest, in which symbiotic bacteria densely populate the lumen of the numerous tubule-like midgut crypts that the chinch bug develops. Cloning and sequence analyses of the 16S rRNA genes revealed that the crypts were dominated by a specific group of bacteria belonging to the genus Burkholderia of the Betaproteobacteria. The Burkholderia sequences were distributed into three distinct clades: the Burkholderia cepacia complex (BCC), the plant-associated beneficial and environmental (PBE) group, and the stinkbug-associated beneficial and environmental group (SBE). Diagnostic PCR revealed that only one of the three groups of Burkholderia was present in ∼89% of the chinch bug field populations tested, while infections with multiple Burkholderia groups within one insect were observed in only ∼10%. Deep sequencing of the 16S rRNA gene confirmed that the Burkholderia bacteria specifically colonized the crypts and were dominated by one of three Burkholderia groups. The lack of phylogenetic congruence between the symbiont and the host population strongly suggested host-symbiont promiscuity, which is probably caused by environmental acquisition of the symbionts by some hosts. Meanwhile, inspections of eggs and hatchlings by diagnostic PCR and egg surface sterilization demonstrated that almost 30% of the hatchlings vertically acquire symbiotic Burkholderia via symbiont-contaminated egg surfaces. The mixed strategy of symbiont transmission found in the oriental chinch bug might be an intermediate stage in evolution from environmental acquisition to strict vertical transmission in insects. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

Attentional Control and the Relatedness Proportion Effect in Semantic Priming

Science.gov (United States)

Hutchison, Keith A.

2007-01-01

In 2 experiments, participants completed both an attentional control battery (OSPAN, antisaccade, and Stroop tasks) and a modified semantic priming task. The priming task measured relatedness proportion (RP) effects within subjects, with the color of the prime indicating the probability that the to-be-named target would be related. In Experiment…

Cultivating American- and Japanese-Style Relatedness through Mother-Child Conversation

Science.gov (United States)

Crane, Lauren Shapiro; Fernald, Anne

2017-01-01

This study investigated whether European American and Japanese mothers' speech to preschoolers contained exchange- and alignment-oriented structures that reflect and possibly support culture-specific models of self-other relatedness. In each country 12 mothers were observed in free play with their 3-year-olds. Maternal speech was coded for…

Expression patterns of mRNAs for methanotrophy and thiotrophy in symbionts of the hydrothermal vent mussel Bathymodiolus puteoserpentis

Science.gov (United States)

Wendeberg, Annelie; Zielinski, Frank U; Borowski, Christian; Dubilier, Nicole

2012-01-01

The hydrothermal vent mussel Bathymodiolus puteoserpentis (Mytilidae) from the Mid-Atlantic Ridge hosts symbiotic sulfur- and methane-oxidizing bacteria in its gills. In this study, we investigated the activity and distribution of these two symbionts in juvenile mussels from the Logatchev hydrothermal vent field (14°45′N Mid-Atlantic Ridge). Expression patterns of two key genes for chemosynthesis were examined: pmoA (encoding subunit A of the particulate methane monooxygenase) as an indicator for methanotrophy, and aprA (encoding the subunit A of the dissimilatory adenosine-5′-phosphosulfate reductase) as an indicator for thiotrophy. Using simultaneous fluorescence in situ hybridization (FISH) of rRNA and mRNA we observed highest mRNA FISH signals toward the ciliated epithelium where seawater enters the gills. The levels of mRNA expression differed between individual specimens collected in a single grab from the same sampling site, whereas no obvious differences in symbiont abundance or distribution were observed. We propose that the symbionts respond to the steep temporal and spatial gradients in methane, reduced sulfur compounds and oxygen by modifying gene transcription, whereas changes in symbiont abundance and distribution take much longer than regulation of mRNA expression and may only occur in response to long-term changes in vent fluid geochemistry. PMID:21734728

Representations of relatedness with parents and friends and autonomous academic motivation during the late adolescence-early adulthood period: reciprocal or unidirectional effects?

Science.gov (United States)

Guay, Frédéric; Marsh, Herbert W; Senécal, Caroline; Dowson, Martin

2008-12-01

The literature on the determinants of academic motivation indicates that social and affective processes connected to students' interpersonal relationships are central elements in understanding students' academic motivation and other school-related outcomes. The aim of this study was to answer the following questions: Does autonomous motivation drive representations of relatedness, do representations of relatedness drive autonomous motivation, or are these constructs reciprocally related over time? The sample consists of 834 adolescents aged 18 years (SD=1.88) who participated in a 3-year longitudinal study. Results from the structural equation models provided good support for the effect of representations of relatedness with parents on autonomous academic motivation but no convincing support for the effect of motivation on representations of relatedness with parents. In addition, no significant effect in either direction was found between representations of relatedness with friends and autonomous academic motivation. It might be important to inform parents that they may still have an influence on their adolescent's representations of relatedness and subsequently on his/her autonomous academic motivation even during the late adolescence-early adulthood period, a period when some parents may be tempted to believe that they can do little to motivate their offspring.

Alternative parameterizations of relatedness in whole genome association analysis of pre-weaning traits of Nelore-Angus calves

Directory of Open Access Journals (Sweden)

David G. Riley

2014-09-01

Full Text Available Gestation length, birth weight, and weaning weight of F2 Nelore-Angus calves (n = 737 with designed extensive full-sibling and half-sibling relatedness were evaluated for association with 34,957 SNP markers. In analyses of birth weight, random relatedness was modeled three ways: 1 none, 2 random animal, pedigree-based relationship matrix, or 3 random animal, genomic relationship matrix. Detected birth weight-SNP associations were 1,200, 735, and 31 for those parameterizations respectively; each additional model refinement removed associations that apparently were a result of the built-in stratification by relatedness. Subsequent analyses of gestation length and weaning weight modeled genomic relatedness; there were 40 and 26 trait-marker associations detected for those traits, respectively. Birth weight associations were on BTA14 except for a single marker on BTA5. Gestation length associations included 37 SNP on BTA21, 2 on BTA27 and one on BTA3. Weaning weight associations were on BTA14 except for a single marker on BTA10. Twenty-one SNP markers on BTA14 were detected in both birth and weaning weight analyses.

A journey into the wild of the cnidarian model system Aiptasia and its symbionts

KAUST Repository

Voolstra, Christian R.

2013-08-27

The existence of coral reef ecosystems relies critically on the mutualistic relationship between calcifying cnidarians and photosynthetic, dinoflagellate endosymbionts in the genus Symbiodinium. Reef-corals have declined globally due to anthropogenic stressors, for example, rising sea-surface temperatures and pollution that often disrupt these symbiotic relationships (known as coral bleaching), exacerbating mass mortality and the spread of disease. This threatens one of the most biodiverse marine ecosystems providing habitats to millions of species and supporting an estimated 500 million people globally (Hoegh-Guldberg et al. 2007). Our understanding of cnidarian-dinoflagellate symbioses has improved notably with the recent application of genomic and transcriptomic tools (e.g. Voolstra et al. 2009; Bayer et al. 2012; Davy et al. 2012), but a model system that allows for easy manipulation in a laboratory environment is needed to decipher underlying cellular mechanisms important to the functioning of these symbioses. To this end, the sea anemone Aiptasia, otherwise known as a \\'pest\\' to aquarium hobbyists, is emerging as such a model system (Schoenberg & Trench 1980; Sunagawa et al. 2009; Lehnert et al. 2012). Aiptasia is easy to grow in culture and, in contrast to its stony relatives, can be maintained aposymbiotically (i.e. dinoflagellate free) with regular feeding. However, we lack basic information on the natural distribution and genetic diversity of these anemones and their endosymbiotic dinoflagellates. These data are essential for placing the significance of this model system into an ecological context. In this issue of Molecular Ecology, Thornhill et al. (2013) are the first to present genetic evidence on the global distribution, diversity and population structure of Aiptasia and its associated Symbiodinium spp. By integrating analyses of the host and symbiont, this research concludes that the current Aitpasia taxonomy probably needs revision and that two

Fostering relatedness between children and virtual agents through reciprocal self-disclosure

NARCIS (Netherlands)

Burger, F.; Broekens, J.; Neerincx, M.A.

2017-01-01

A key challenge in developing companion agents for children is keeping them interested after novelty effects wear off. Self Determination Theory posits that motivation is sustained if the human feels related to another human. According to Social Penetration Theory, relatedness can be established

Work-relatedness of lung cancer by smoking and histologic type in Korea.

Science.gov (United States)

Lee, Young-Il; Lee, Sang-Gil; Kang, Dong-Mug; Kim, Jong-Eun; Kim, Young-Ki; Leem, Jong-Han; Kim, Hwan-Cheol

2014-01-01

This study investigated the distribution of causative agents related to occupational lung cancer, their relationships with work, and associations between work-relatedness and the histologic type of lung cancer. We used data from the occupational surveillance system in Korea in 2013. In addition, data from 1,404 participants diagnosed with lung cancer were collected through interviews. We included the patients' longest-held job in the analysis. Work-relatedness was categorized as "definite," "probable," "possible," "suspicious," "none," or "undetermined." Among the subjects, 69.3% were men and 30.7% were women. Regarding smoking status, current smokers were the most prevalent (35.5%), followed by non-smokers (32.3%), ex-smokers (32.2%). Regarding the causative agents of lung cancer, asbestos (1.0%) and crystalline silica (0.9%) were the most common in definite work-related cases, while non-arsenical insecticide (2.8%) was the most common in probable cases followed by diesel engine exhaust (1.9%) and asbestos (1.0%). Regarding histologic type, adenocarcinoma was the most common (41.7%), followed by squamous cell carcinoma (21.2%). Among current smokers, squamous cell carcinoma was the most common among definite and probable cases (13.4%), while non-small cell lung cancer was the least common (7.1%). Among non-smokers, squamous cell carcinoma was the most common (21.4%), while the least common was adenocarcinoma (1.6%). Approximately, 9.5% of all lung cancer cases in Korea are occupational-related lung cancer. Well-known substances associated with lung cancer, such as crystalline silica, asbestos, and diesel engine exhaust, are of particular concern. However, the histologic types of lung cancer related to smoking were inconsistent with previous studies when work-relatedness was taken into account. Future studies are required to clarify the incidence of occupational lung cancer in agricultural workers exposed to non-arsenical insecticides and the associations between

The efficacy of exergames for social relatedness in online physical education

Directory of Open Access Journals (Sweden)

Brian J. Kooiman

2015-12-01

Full Text Available Online physical education (OLPE has been viewed as an oxymoron. Physical education curriculum at all levels seeks to help learners grow socially in the way they interact and deal with diverse and challenging fellow students and settings. Students who have no contact with other students while they are at home for various reasons may not be able to learn the proper response to the challenges of social participation or benefits derived from social contact. This study looked at the efficacy of remote exergame participation between students aged 11–18 (N = 124. The results show that exergaming over the Internet can provide students with a social experience that results in increased relatedness between participants versus playing by themselves against a non-player character (NPC. This relatedness can help students access the social standards for physical education when enrolled in OLPE.

The Development of a Social Networking-Based Relatedness Intervention Among Young, First-Time Blood Donors: Pilot Study.

Science.gov (United States)

Frye, Victoria; Duffy, Louisa; France, Janis L; Kessler, Debra A; Rebosa, Mark; Shaz, Beth H; Carlson, Bruce W; France, Christopher R

2018-04-26

Increasing repeat blood donation behavior is a critical public health goal. According to self-determination theory, the process of developing internal motivation to give blood and an associated self-identity as a blood donor may be promoted by feelings of “relatedness” or a connection to other donors, which may be enhanced through social relations and interactions. The purpose of this report it to describe the development and pilot testing of a social networking-based (Facebook) intervention condition designed to increase feelings of relatedness via virtual social interaction and support. To develop the intervention condition content, images, text, polls, and video content were assembled. Ohio University college students (N=127) rated the content (82 images/text) presented by computer in random order using a scale of one to five on various dimensions of relatedness. Mean ratings were calculated and analyses of variance were conducted to assess associations among the dimensions. Based on these results, the relatedness intervention was adapted and evaluated for feasibility, acceptability, and preliminary efficacy among 24 first-time donors, aged 18 to 24 years, in a 30-day pilot trial. Paired t-tests were conducted to examine change over time in relatedness and connectedness. The intervention condition that was developed was acceptable and feasible. Results of the uncontrolled, preintervention, and postintervention evaluation revealed that feelings of individual-level relatedness increased significantly after the intervention. By promoting first-time blood donor relatedness, our goal is to enhance internal motivation for donating and the integration of the blood donor identity, thus increasing the likelihood of future repeat donation. ClinicalTrials.gov NCT02717338; https://clinicaltrials.gov/ct2/show/NCT02717338 (Archived by WebCite at http://www.webcitation.org/6ymHRBCwu) ©Victoria Frye, Louisa Duffy, Janis L France, Debra A Kessler, Mark Rebosa, Beth H Shaz

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

Directory of Open Access Journals (Sweden)

Gily Merkado

Full Text Available The Mediterranean Sea is considered as one of the hotspots of marine bioinvasions, largely due to the influx of tropical species migrating through the Suez Canal, so-called Lessepsian migrants. Several cases of Lessepsian migration have been documented recently, however, little is known about the ecological characteristics of the migrating species and their aptitude to colonize the new areas. This study focused on Red Sea soritids, larger symbiont-bearing benthic foraminifera (LBF that are indicative of tropical and subtropical environments and were recently found in the Israeli coast of the Eastern Mediterranean. We combined molecular phylogenetic analyses of soritids and their algal symbionts as well as network analysis of Sorites orbiculus Forskål to compare populations from the Gulf of Elat (northern Red Sea and from a known hotspot in Shikmona (northern Israel that consists of a single population of S. orbiculus. Our phylogenetic analyses show that all specimens found in Shikmona are genetically identical to a population of S. orbiculus living on a similar shallow water pebbles habitat in the Gulf of Elat. Our analyses also show that the symbionts found in Shikmona and Elat soritids belong to the Symbiodinium clade F5, which is common in the Red Sea and also present in the Indian Ocean and Caribbean Sea. Our study therefore provides the first genetic and ecological evidences that indicate that modern population of soritids found on the Mediterranean coast of Israel is probably Lessepsian, and is less likely the descendant of a native ancient Mediterranean species.

Down under the tunic: bacterial biodiversity hotspots and widespread ammonia-oxidizing archaea in coral reef ascidians.

Science.gov (United States)

Erwin, Patrick M; Pineda, Mari Carmen; Webster, Nicole; Turon, Xavier; López-Legentil, Susanna

2014-03-01

Ascidians are ecologically important components of marine ecosystems yet the ascidian microbiota remains largely unexplored beyond a few model species. We used 16S rRNA gene tag pyrosequencing to provide a comprehensive characterization of microbial symbionts in the tunic of 42 Great Barrier Reef ascidian samples representing 25 species. Results revealed high bacterial biodiversity (3 217 unique operational taxonomic units (OTU0.03) from 19 described and 14 candidate phyla) and the widespread occurrence of ammonia-oxidizing Thaumarchaeota in coral reef ascidians (24 of 25 host species). The ascidian microbiota was clearly differentiated from seawater microbial communities and included symbiont lineages shared with other invertebrate hosts as well as unique, ascidian-specific phylotypes. Several rare seawater microbes were markedly enriched (200-700 fold) in the ascidian tunic, suggesting that the rare biosphere of seawater may act as a conduit for horizontal symbiont transfer. However, most OTUs (71%) were rare and specific to single hosts and a significant correlation between host relatedness and symbiont community similarity was detected, indicating a high degree of host-specificity and potential role of vertical transmission in structuring these communities. We hypothesize that the complex ascidian microbiota revealed herein is maintained by the dynamic microenvironments within the ascidian tunic, offering optimal conditions for different metabolic pathways such as ample chemical substrate (ammonia-rich host waste) and physical habitat (high oxygen, low irradiance) for nitrification. Thus, ascidian hosts provide unique and fertile niches for diverse microorganisms and may represent an important and previously unrecognized habitat for nitrite/nitrate regeneration in coral reef ecosystems.

How teacher emotional support motivates students: The mediating roles of perceived peer relatedness, autonomy support, and competence

Science.gov (United States)

Ruzek, Erik A.; Hafen, Christopher A.; Allen, Joseph P.; Gregory, Anne; Mikami, Amori Yee; Pianta, Robert C.

2017-01-01

Multilevel mediation analyses test whether students' mid-year reports of classroom experiences of autonomy, relatedness with peers, and competence mediate associations between early in the school year emotionally-supportive teacher-student interactions (independently observed) and student-reported academic year changes in mastery motivation and behavioral engagement. When teachers were observed to be more emotionally-supportive in the beginning of the school year, adolescents reported academic year increases in their behavioral engagement and mastery motivation. Mid-year student reports indicated that in emotionally-supportive classrooms, adolescents experienced more developmentally-appropriate opportunities to exercise autonomy in their day-to-day activities and had more positive relationships with their peers. Analyses of the indirect effects of teacher emotional support on students' engagement and motivation indicated significant mediating effects of autonomy and peer relatedness experiences, but not competence beliefs, in this sample of 960 students (ages 11–17) in the classrooms of 68 middle and high school teachers in 12 U.S. schools. PMID:28190936

How teacher emotional support motivates students: The mediating roles of perceived peer relatedness, autonomy support, and competence.

Science.gov (United States)

Ruzek, Erik A; Hafen, Christopher A; Allen, Joseph P; Gregory, Anne; Mikami, Amori Yee; Pianta, Robert C

2016-04-01

Multilevel mediation analyses test whether students' mid-year reports of classroom experiences of autonomy, relatedness with peers, and competence mediate associations between early in the school year emotionally-supportive teacher-student interactions (independently observed) and student-reported academic year changes in mastery motivation and behavioral engagement. When teachers were observed to be more emotionally-supportive in the beginning of the school year, adolescents reported academic year increases in their behavioral engagement and mastery motivation. Mid-year student reports indicated that in emotionally-supportive classrooms, adolescents experienced more developmentally-appropriate opportunities to exercise autonomy in their day-to-day activities and had more positive relationships with their peers. Analyses of the indirect effects of teacher emotional support on students' engagement and motivation indicated significant mediating effects of autonomy and peer relatedness experiences, but not competence beliefs, in this sample of 960 students (ages 11-17) in the classrooms of 68 middle and high school teachers in 12 U.S. schools.

Phylogeographical patterns among Mediterranean sepiolid squids and their Vibrio symbionts: environment drives specificity among sympatric species.

Science.gov (United States)

Zamborsky, D J; Nishiguchi, M K

2011-01-01

Bobtail squid from the genera Sepiola and Rondeletiola (Cephalopoda: Sepiolidae) form mutualistic associations with luminous Gram-negative bacteria (Gammaproteobacteria: Vibrionaceae) from the genera Vibrio and Photobacterium. Symbiotic bacteria proliferate inside a bilobed light organ until they are actively expelled by the host into the surrounding environment on a diel basis. This event results in a dynamic symbiont population with the potential to establish the symbiosis with newly hatched sterile (axenic) juvenile sepiolids. In this study, we examined the genetic diversity found in populations of sympatric sepiolid squid species and their symbionts by the use of nested clade analysis with multiple gene analyses. Variation found in the distribution of different species of symbiotic bacteria suggests a strong influence of abiotic factors in the local environment, affecting bacterial distribution among sympatric populations of hosts. These abiotic factors include temperature differences incurred by a shallow thermocline, as well as a lack of strong coastal water movement accompanied by seasonal temperature changes in overlapping niches. Host populations are stable and do not appear to have a significant role in the formation of symbiont populations relative to their distribution across the Mediterranean Sea. Additionally, all squid species examined (Sepiola affinis, S. robusta, S. ligulata, S. intermedia, and Rondeletiola minor) are genetically distinct from one another regardless of location and demonstrate very little intraspecific variation within species. These findings suggest that physical boundaries and distance in relation to population size, and not host specificity, are important factors in limiting or defining gene flow within sympatric marine squids and their associated bacterial symbionts in the Mediterranean Sea.

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

African Journals Online (AJOL)

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

A motivation model for interaction between parent and child based on the need for relatedness

Directory of Open Access Journals (Sweden)

Masaki eOgino

2013-09-01

Full Text Available In communication between parents and children, various kinds of intrinsic and extrinsic motivations affect the emotions that encourage actions to promote more interactions. This paper presents a motivation model for the interaction between an infant and a caregiver which models relatedness, one of the most important basic psychological needs, as a variable that increases with experiences of emotion sharing. Relatedness is not only an important factor of pleasure but also a meta-factor which affects other factors such as stress and emotion mirroring. In the simulation experiment, two agents, each of which has the proposed motivation model, show emotional communication depending on the relatedness level that is similar to actual human communication. Especially, the proposed model can reproduce a finding described by the "still-face paradigm", in which an infant shows unpleasant emotion when a caregiver suddenly stops facial expressions. The proposed model is implemented in an artificial agent with a recognition system for gestures and facial expressions. The baby-like agent successfully interacts with an actual human and shows reactions comparable to the "still-face paradigm".

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

Science.gov (United States)

Ho, Jessica S.; Geske, Grant D.; Blackwell, Helen E.; Ruby, Edward G.

2014-01-01

SUMMARY Quorum sensing, a group behavior coordinated by a diffusible pheromone signal and a cognate receptor, is typical of bacteria that form symbioses with plants and animals. LuxIR-type acyl homoserine-lactone (AHL) quorum sensing is common in Gram-negative proteobacteria, and many members of this group have additional quorum-sensing networks. The bioluminescent symbiont Vibrio fischeri encodes two AHL signal synthases: AinS and LuxI. AinS-dependent quorum sensing converges with LuxI-dependent quorum sensing at the LuxR regulatory element. Both AinS- and LuxI-mediated signaling are required for efficient and persistent colonization of the squid host, Euprymna scolopes. The basis of the mutualism is symbiont bioluminescence, which is regulated by both LuxI- and AinS-dependent quorum sensing, and is essential for maintaining a colonization of the host. Here, we used chemical and genetic approaches to probe the dynamics of LuxI- and AinS-mediated regulation of bioluminescence during symbiosis. We demonstrate that both native AHLs and non-native AHL analogs can be used to non-invasively and specifically modulate induction of symbiotic bioluminescence via LuxI-dependent quorum sensing. Our data suggest that the first day of colonization, during which symbiont bioluminescence is induced by LuxIR, is a critical period that determines the stability of the V. fischeri population once symbiosis is established. PMID:24191970

Identifying the cellular mechanisms of symbiont-induced epithelial morphogenesis in the squid-Vibrio association.

Science.gov (United States)

Koropatnick, Tanya; Goodson, Michael S; Heath-Heckman, Elizabeth A C; McFall-Ngai, Margaret

2014-02-01

The symbiotic association between the Hawaiian bobtail squid Euprymna scolopes and the luminous marine bacterium Vibrio fischeri provides a unique opportunity to study epithelial morphogenesis. Shortly after hatching, the squid host harvests bacteria from the seawater using currents created by two elaborate fields of ciliated epithelia on the surface of the juvenile light organ. After light organ colonization, the symbiont population signals the gradual loss of the ciliated epithelia through apoptosis of the cells, which culminates in the complete regression of these tissues. Whereas aspects of this process have been studied at the morphological, biochemical, and molecular levels, no in-depth analysis of the cellular events has been reported. Here we describe the cellular structure of the epithelial field and present evidence that the symbiosis-induced regression occurs in two steps. Using confocal microscopic analyses, we observed an initial epithelial remodeling, which serves to disable the function of the harvesting apparatus, followed by a protracted regression involving actin rearrangements and epithelial cell extrusion. We identified a metal-dependent gelatinolytic activity in the symbiont-induced morphogenic epithelial fields, suggesting the involvement of Zn-dependent matrix metalloproteinase(s) (MMP) in light organ morphogenesis. These data show that the bacterial symbionts not only induce apoptosis of the field, but also change the form, function, and biochemistry of the cells as part of the morphogenic program.

Associations Among Psychologically Controlling Parenting, Autonomy, Relatedness, and Problem Behaviors During Emerging Adulthood.

Science.gov (United States)

Liga, Francesca; Ingoglia, Sonia; Inguglia, Cristiano; Lo Coco, Alida; Lo Cricchio, Maria Grazia; Musso, Pasquale; Cheah, Charissa; Rose, Laura; Gutow, Mindy R

2017-05-19

The present study aimed to investigate the relations among perceived parental psychological control (PPC), autonomy and relatedness, and negative outcomes during emerging adulthood in two cultural contexts: Italy and the USA. More specifically, we explored the mechanisms through which dependency-oriented PPC (DPPC) and achievement-oriented PPC (APPC) are associated with both internalizing and externalizing difficulties, focusing on the mediating role of autonomy and relatedness. Participants were 418 European-American and 359 Italian college students. Results indicated that the expressions of PPC with regard to dependency and achievement were related to emerging adults' negative outcomes through different pathways, and these effects were moderated by the cultural group. The implications of the findings for future related empirical investigations and clinical interventions were discussed.

Insight into the genomic diversity and relationship of Astragalus glycyphyllos symbionts by RAPD, ERIC-PCR, and AFLP fingerprinting.

Science.gov (United States)

Gnat, Sebastian; Małek, Wanda; Oleńska, Ewa; Trościańczyk, Aleksandra; Wdowiak-Wróbel, Sylwia; Kalita, Michał; Wójcik, Magdalena

2015-11-01

We assessed the genomic diversity and genomic relationship of 28 Astragalus glycyphyllos symbionts by three methodologies based on PCR reaction, i.e., RAPD, ERIC-PCR, and AFLP. The AFLP method with one PstI restriction enzyme and selective PstI-GC primer pair had a comparable discriminatory power as ERIC-PCR one and these fingerprinting techniques distinguished among the studied 28 A. glycyphyllos symbionts 18 and 17 genomotypes, respectively. RAPD method was less discriminatory in the genomotyping of rhizobia analyzed and it efficiently resolved nine genomotypes. The cluster analysis of RAPD, ERIC-PCR, and AFLP profiles resulted in a generally similar grouping of the test strains on generated dendrograms supporting a great potential of these DNA fingerprinting techniques for study of genomic polymorphism and evolutionary relationship of A. glycyphyllos nodulators. The RAPD, ERIC-PCR, and AFLP pattern similarity coefficients between A. glycyphyllos symbionts studied was in the ranges 8-100, 18-100, and 23-100%, respectively.

Anemone bleaching increases the metabolic demands of symbiont anemonefish.

Science.gov (United States)

Norin, Tommy; Mills, Suzanne C; Crespel, Amélie; Cortese, Daphne; Killen, Shaun S; Beldade, Ricardo

2018-04-11

Increased ocean temperatures are causing mass bleaching of anemones and corals in the tropics worldwide. While such heat-induced loss of algal symbionts (zooxanthellae) directly affects anemones and corals physiologically, this damage may also cascade on to other animal symbionts. Metabolic rate is an integrative physiological trait shown to relate to various aspects of organismal performance, behaviour and locomotor capacity, and also shows plasticity during exposure to acute and chronic stressors. As climate warming is expected to affect the physiology, behaviour and life history of animals, including ectotherms such as fish, we measured if residing in bleached versus unbleached sea anemones ( Heteractis magnifica ) affected the standard (i.e. baseline) metabolic rate and behaviour (activity) of juvenile orange-fin anemonefish ( Amphiprion chrysopterus ) . Metabolic rate was estimated from rates of oxygen uptake [Formula: see text], and the standard metabolic rate [Formula: see text] of anemonefish from bleached anemones was significantly higher by 8.2% compared with that of fish residing in unbleached anemones, possibly due to increased stress levels. Activity levels did not differ between fish from bleached and unbleached anemones. As [Formula: see text] reflects the minimum cost of living, the increased metabolic demands may contribute to the negative impacts of bleaching on important anemonefish life history and fitness traits observed previously (e.g. reduced spawning frequency and lower fecundity). © 2018 The Author(s).

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

Directory of Open Access Journals (Sweden)

Yao Xu

2016-11-01

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

The Effects of Collaborative Care of Living Animals in Biology Lessons on Students' Relatedness Toward Their Teacher Across Gender

Science.gov (United States)

Eckes, Alexander; Großmann, Nadine; Wilde, Matthias

2018-01-01

The transition from elementary school to the upper grades can lead to ambiguous feelings toward the new, male teachers. This study investigated whether collaborative animal care in biology lessons affects students' feelings of relatedness toward their biology teachers positively during the first year after the school transition. Four hundred twenty fifth graders (M age = 10.5 years, SD age = 0.6 years) of higher types of tracking participated. We designed one experimental group that involved caring for the living animals to be used in the upcoming lessons, and two control groups. The first control group included lessons with living animals, but did not include prior care of those animals, and the second incorporated neither living animals nor prior care. All groups received biology lessons with the same content. To examine the effects of caretaking, we used an adapted version of the scale "relatedness" (Ryan 1982). In both control groups, boys showed lower relatedness toward female teachers and girls toward male teachers, respectively. Collaborative mice care promoted equal relatedness across all gender combinations among teachers and students.

Individuality and relatedness in middle and late adulthood. A study of women and men in the Netherlands, East-, and West-Germany

NARCIS (Netherlands)

Bode, C.

2003-01-01

Individuality and relatedness are two comprehensive orientations during the whole life course. Scientific knowledge regarding the subjective importance and meaning of individuality and relatedness in middle and late adulthood is scarcely available. This thesis investigates the quantitative as well

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

Directory of Open Access Journals (Sweden)

Steven A Frese

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

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

NARCIS (Netherlands)

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

2009-01-01

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

Genetic relatedness and spatial associations of dusky-footed woodrats (Neotoma fuscipes)

Science.gov (United States)

Robin J. Innes; Mary Brooke McEachern; Dirk H. Van Vuren; John M. Eadie; Douglas A. Kelt; Michael L. Johnson

2012-01-01

We studied the association between space sharing and kinship in a solitary rodent, the dusky-footed woodrat (Neotoma fuscipes). Genetic relatedness was inversely correlated with geographic distance for female woodrats but not for males, a pattern consistent with female philopatry and male dispersal. However, some female neighbors were unrelated, suggesting the...

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

Directory of Open Access Journals (Sweden)

Christopher M Taylor

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

Resistance and relatedness on an evolutionary graph

Science.gov (United States)

Maciejewski, Wes

2012-01-01

When investigating evolution in structured populations, it is often convenient to consider the population as an evolutionary graph—individuals as nodes, and whom they may act with as edges. There has, in recent years, been a surge of interest in evolutionary graphs, especially in the study of the evolution of social behaviours. An inclusive fitness framework is best suited for this type of study. A central requirement for an inclusive fitness analysis is an expression for the genetic similarity between individuals residing on the graph. This has been a major hindrance for work in this area as highly technical mathematics are often required. Here, I derive a result that links genetic relatedness between haploid individuals on an evolutionary graph to the resistance between vertices on a corresponding electrical network. An example that demonstrates the potential computational advantage of this result over contemporary approaches is provided. This result offers more, however, to the study of population genetics than strictly computationally efficient methods. By establishing a link between gene transfer and electric circuit theory, conceptualizations of the latter can enhance understanding of the former. PMID:21849384

Male-male aggression peaks at intermediate relatedness in a social spider mite

NARCIS (Netherlands)

Sato, Y.; Egas, M.; Sabelis, M.W.; Mochizuki, A.

2013-01-01

Theory predicts that when individuals live in groups or colonies, male-male aggression peaks at intermediate levels of local average relatedness. Assuming that aggression is costly and directed toward nonrelatives and that competition for reproduction acts within the colony, benefits of aggressive

Standing genetic variation in host preference for mutualist microbial symbionts.

Science.gov (United States)

Simonsen, Anna K; Stinchcombe, John R

2014-12-22

Many models of mutualisms show that mutualisms are unstable if hosts lack mechanisms enabling preferential associations with mutualistic symbiotic partners over exploitative partners. Despite the theoretical importance of mutualism-stabilizing mechanisms, we have little empirical evidence to infer their evolutionary dynamics in response to exploitation by non-beneficial partners. Using a model mutualism-the interaction between legumes and nitrogen-fixing soil symbionts-we tested for quantitative genetic variation in plant responses to mutualistic and exploitative symbiotic rhizobia in controlled greenhouse conditions. We found significant broad-sense heritability in a legume host's preferential association with mutualistic over exploitative symbionts and selection to reduce frequency of associations with exploitative partners. We failed to detect evidence that selection will favour the loss of mutualism-stabilizing mechanisms in the absence of exploitation, as we found no evidence for a fitness cost to the host trait or indirect selection on genetically correlated traits. Our results show that genetic variation in the ability to preferentially reduce associations with an exploitative partner exists within mutualisms and is under selection, indicating that micro-evolutionary responses in mutualism-stabilizing traits in the face of rapidly evolving mutualistic and exploitative symbiotic bacteria can occur in natural host populations. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

The mediating role of relatedness need satisfaction in the relationship between charitable behavior and well-being: Empirical evidence from China.

Science.gov (United States)

Jiang, Jiang; Zeng, Taoran; Zhang, Chong; Wang, Rong

2016-08-03

Based on self-determination theory, the current research aimed to explore the potential mediating effect of relatedness need satisfaction on the relationship between charitable behavior and well-being in the Chinese context. Employing a cross-sectional design, participants reported data on the aforementioned variables in Study 1. The results indicated that relatedness need satisfaction mediated the positive relationship between charitable behavior and hedonic well-being and that between charitable behavior and eudaimonic well-being. Subsequently, a field experiment was conducted in Study 2. Participants rated their levels of relatedness need satisfaction and well-being after charitable donation behaviors were primed. We again observed consistent results. Specifically, charitable behavior was positively associated with both hedonic and eudaimonic well-being, and these relationships were mediated by relatedness need satisfaction. The above findings help to clarify the association between charitable behavior and people's subjective feelings (i.e., well-being), and they deepen our understanding of the underlying mechanism from the perspective of psychological needs satisfaction. © 2016 International Union of Psychological Science.

Study of Colombia North Wiwa El Encanto Amerindians HLA- genes: Pacific Islanders relatedness.

Science.gov (United States)

Arnaiz-Villena, Antonio; Palacio-Grüber, Jose; Juarez, Ignacio; Muñiz, Ester; Hernández, Ennio; Bayona, Brayan; Campos, Cristina; Nuñez, Jorge; Lopez-Nares, Adrian; Martin-Villa, Manuel; Silvera, Carlos

2018-07-01

We have studied Wiwa/Sanja Amerindians HLA-A, -B, -C, -DRB1 and DQB1 allele frequencies and extended haplotypes in 52 unrelated individuals from "El Encanto" town at Guanachaca riverside. High frequency alleles were in general present in other Amerindian populations. Also, three extended haplotypes and eight ones were respectively both "new found" and already described in Amerindians from North, Central and South America, including Lakota-Sioux, Mayas, Teeneks, Quechua and Aymaras. Analyses of HLA-A*24:02 and -C*01:02 Wiwa high frequency alleles suggested a specific relatedness with another Amerindian and Pacific Islander ethnic groups (these two particular alleles bearing in high frequencies); they include New Zealand Maoris, Taiwanese, Japanese, Papua New Guinea, and Samoans among others. This may indicate that selective forces are maintaining these two alleles high frequency within this wide American/Pacific area. Copyright © 2018. Published by Elsevier Inc.

Relatedness Need Satisfaction, Intrinsic Motivation, and Engagement in Secondary School Physical Education

Science.gov (United States)

Xiang, Ping; Agbuga, Bülent; Liu, Jiling; McBride, Ron E.

2017-01-01

Purpose: Using self-determination theory, this study examined unique contributions of relatedness need satisfaction (to both teachers and peers) to intrinsic motivation and engagement (behavioral, cognitive, and emotional) over and above those of autonomy need satisfaction and competence need satisfaction among Turkish students in secondary school…

Applying self-determination theory to the blood donation context: The blood donor competence, autonomy, and relatedness enhancement (Blood Donor CARE) trial.

Science.gov (United States)

France, Christopher R; France, Janis L; Carlson, Bruce W; Frye, Victoria; Duffy, Louisa; Kessler, Debra A; Rebosa, Mark; Shaz, Beth H

2017-02-01

The Blood Donor Competency, Autonomy, and Relatedness Enhancement (Blood Donor CARE) project was designed as a practical application of self-determination theory to encourage retention of first-time donors. Self-determination theory proposes that people are more likely to persist with behaviors that are internally-motivated, and that externally-motivated behavior can evolve and become internalized given the appropriate socio-environmental conditions. According to self-determination theory, motivation to engage in blood donation may become increasingly self-determined if the behavior satisfies fundamental human needs for competence (a sense of self-efficacy to achieve specific goals), autonomy (a sense of volitional control over one's behavior), and relatedness (a sense of connection to a larger group). The primary aim of this randomized controlled trial is to examine the effect of competence, autonomy, and/or relatedness interventions on donor retention. Using a full factorial design, first-time donors will be assigned to a control condition or one of seven intervention conditions. Donation competence, autonomy, and relatedness, along with additional constructs associated with return donation, will be assessed before and after the intervention using online surveys, and donation attempts will be tracked for one-year using blood center donor databases. We hypothesize that, compared to the control condition, the interventions will increase the likelihood of a subsequent donation attempt. We will also examine intervention-specific increases in competence, autonomy, and relatedness as potential mediators of enhanced donor retention. By promoting first-time donor competence, autonomy, and relatedness our goal is to enhance internal motivation for giving and in so doing increase the likelihood of future donation. Copyright © 2016 Elsevier Inc. All rights reserved.

Exploring the Influence of Nature Relatedness and Perceived Science Knowledge on Proenvironmental Behavior

Directory of Open Access Journals (Sweden)

Amanda Obery

2017-01-01

Full Text Available This study was undertaken to investigate the factors influencing proenvironmental behavior of individuals residing in the Northern Rocky Mountains (N = 267. Measures of relatedness to nature and perceived science knowledge were collected through a convenience sample approach using multiple avenues such as city email lists, organizational newsletters, and social media channels. Analysis of the data was conducted using both partial least squares and covariance based structural equation modeling to explore the relationships between the constructs. Additionally, qualitative definitions of proenvironmental behavior were investigated in order to address potential gaps between self-reported and observed behaviors. Quantitative findings show a renewed positive connection between science education, nature relatedness, and proenvironmental behaviors. Furthermore, qualitative findings suggest positive relationships between how publicly people are willing to share their passion for the outdoors and their willingness to engage in proenvironmental behaviors.

Local endemicity and high diversity characterise high-latitude coral- Symbiodinium partnerships

Science.gov (United States)

Wicks, L. C.; Sampayo, E.; Gardner, J. P. A.; Davy, S. K.

2010-12-01

Obligate symbiotic dinoflagellates ( Symbiodinium) residing within the tissues of most reef invertebrates are important in determining the tolerance range of their host. Coral communities living at high latitudes experience wide fluctuations in environmental conditions and thus provide an ideal system to gain insights into the range within which the symbiotic relationship can be sustained. Further, understanding whether and how symbiont communities associated with high-latitude coral reefs are different from their tropical counterparts will provide clues to the potential of corals to cope with marginal or changing conditions. However, little is known of the host and symbiont partnerships at high latitudes. Symbiodinium diversity and specificity of high-latitude coral communities were explored using denaturing gradient gel electrophoresis (PCR-DGGE) analysis of the internal transcribed spacer regions (ITS1 and ITS2) of the ribosomal DNA at Lord Howe Island (31°S; Australia), and the Kermadec Islands (29°S; New Zealand). All but one host associated with clade C Symbiodinium, the exception being a soft coral ( Capnella sp.) that contained Symbiodinium B1. Besides ‘host-generalist’ Symbiodinium types C1 and C3, approximately 72% of the Symbiodinium identified were novel C types, and zonation of symbionts in relation to environmental parameters such as depth and turbidity was evident in certain host species. The high-latitude Symbiodinium communities showed little overlap and relatively high diversity compared with communities sampled on the tropical Great Barrier Reef. Although host specificity was maintained in certain species, others shared symbionts and this potential reduction of fidelity at high-latitude locations may be the result of locally challenging and highly variable environmental conditions.

Genetic relatedness of faecal coliforms and enterococci bacteria isolated from water and sediments of the Apies River, Gauteng, South Africa.

Science.gov (United States)

Ekwanzala, Mutshiene Deogratias; Abia, Akebe Luther King; Ubomba-Jaswa, Eunice; Keshri, Jitendra; Momba, Ndombo Benteke Maggy

2017-12-01

To date, the microbiological quality of river sediments and its impact on water resources are not included in the water quality monitoring assessment. Therefore, the aim of this study was to establish genetic relatedness between faecal coliforms and enterococci isolated from the river water and riverbed sediments of Apies River to better understand the genetic similarity of microorganisms between the sediment and water phases. Indicator bacteria were subjected to a molecular study, which consisted of PCR amplification and sequence analysis of the 16S rRNA and 23S rRNA gene using specific primers for faecal coliforms and enterococci, respectively. Results revealed that the Apies River had high faecal pollution levels with enterococci showing low to moderate correlation coefficient (r 2 values ranged from 0.2605 to 0.7499) compared to the faecal coliforms which showed zero to low correlation (r 2 values ranged from 0.0027 to 0.1407) indicating that enterococci may be better indicator than faecal coliforms for detecting faecal contamination in riverbed sediments. The phylogenetic tree of faecal coliforms revealed a 98% homology among their nucleotide sequences confirming the close genetic relatedness between river water and riverbed sediment isolates. The phylogenetic tree of the enterococci showed that Enterococcus faecalis and Enterococcus faecium are the predominant species found in both river water and riverbed sediments with bootstrap values of ≥99%. A high degree of genetic relatedness between sediment and water isolates indicated a possible common ancestry and transmission pathway. We recommend the microbial monitoring of riverbed sediments as it harbours more diverse microbial community and once resuspended may cause health and environmental problems.

Fostering Students' Moderation Competence: The Interplay between Social Relatedness and Perceived Competence

Science.gov (United States)

Bürgermeister, Anika; Ringeisen, Tobias; Raufelder, Diana

2016-01-01

Using a longitudinal design, the present study examined whether two teaching concepts that varied in their capacity to foster students' self-determination affected students' sense of social relatedness and their perceived moderation competence, as well as the interplay between these two components and the students' performance during a moderation…

Stringent Expression Control of Pathogenic R-body Production in Legume Symbiont Azorhizobium caulinodans

Directory of Open Access Journals (Sweden)

Jun-ichi Matsuoka

2017-07-01

Full Text Available R bodies are insoluble large polymers consisting of small proteins encoded by reb genes and are coiled into cylindrical structures in bacterial cells. They were first discovered in Caedibacter species, which are obligate endosymbionts of paramecia. Caedibacter confers a killer trait on the host paramecia. R-body-producing symbionts are released from their host paramecia and kill symbiont-free paramecia after ingestion. The roles of R bodies have not been explained in bacteria other than Caedibacter. Azorhizobium caulinodans ORS571, a microsymbiont of the legume Sesbania rostrata, carries a reb operon containing four reb genes that are regulated by the repressor PraR. Herein, deletion of the praR gene resulted in R-body formation and death of host plant cells. The rebR gene in the reb operon encodes an activator. Three PraR binding sites and a RebR binding site are present in the promoter region of the reb operon. Expression analyses using strains with mutations within the PraR binding site and/or the RebR binding site revealed that PraR and RebR directly control the expression of the reb operon and that PraR dominantly represses reb expression. Furthermore, we found that the reb operon is highly expressed at low temperatures and that 2-oxoglutarate induces the expression of the reb operon by inhibiting PraR binding to the reb promoter. We conclude that R bodies are toxic not only in paramecium symbiosis but also in relationships between other bacteria and eukaryotic cells and that R-body formation is controlled by environmental factors.

Characterizing the host and symbiont proteomes in the association between the Bobtail squid, Euprymna scolopes, and the bacterium, Vibrio fischeri.

Directory of Open Access Journals (Sweden)

Tyler R Schleicher

Full Text Available The beneficial symbiosis between the Hawaiian bobtail squid, Euprymna scolopes, and the bioluminescent bacterium, Vibrio fischeri, provides a unique opportunity to study host/microbe interactions within a natural microenvironment. Colonization of the squid light organ by V. fischeri begins a lifelong association with a regulated daily rhythm. Each morning the host expels an exudate from the light organ consisting of 95% of the symbiont population in addition to host hemocytes and shed epithelial cells. We analyzed the host and symbiont proteomes of adult squid exudate and surrounding light organ epithelial tissue using 1D- and 2D-polyacrylamide gel electrophoresis and multidimensional protein identification technology (MudPIT in an effort to understand the contribution of both partners to the maintenance of this association. These proteomic analyses putatively identified 1581 unique proteins, 870 proteins originating from the symbiont and 711 from the host. Identified host proteins indicate a role of the innate immune system and reactive oxygen species (ROS in regulating the symbiosis. Symbiont proteins detected enhance our understanding of the role of quorum sensing, two-component signaling, motility, and detoxification of ROS and reactive nitrogen species (RNS inside the light organ. This study offers the first proteomic analysis of the symbiotic microenvironment of the adult light organ and provides the identification of proteins important to the regulation of this beneficial association.

Acetic Acid Bacteria as Symbionts of Insects

KAUST Repository

Crotti, Elena; Chouaia, Bessem; Alma, Alberto; Favia, Guido; Bandi, Claudio; Bourtzis, Kostas; Daffonchio, Daniele

2016-01-01

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

Acetic Acid Bacteria as Symbionts of Insects

KAUST Repository

Crotti, Elena

2016-06-14

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

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

NARCIS (Netherlands)

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

2006-01-01

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

Comparative Genomics of the Dual-Obligate Symbionts from the Treehopper, Entylia carinata (Hemiptera: Membracidae), Provide Insight into the Origins and Evolution of an Ancient Symbiosis.

Science.gov (United States)

Mao, Meng; Yang, Xiushuai; Poff, Kirsten; Bennett, Gordon

2017-06-01

Insect species in the Auchenorrhyncha suborder (Hemiptera) maintain ancient obligate symbioses with bacteria that provide essential amino acids (EAAs) deficient in their plant-sap diets. Molecular studies have revealed that two complementary symbiont lineages, "Candidatus Sulcia muelleri" and a betaproteobacterium ("Ca. Zinderia insecticola" in spittlebugs [Cercopoidea] and "Ca. Nasuia deltocephalinicola" in leafhoppers [Cicadellidae]) may have persisted in the suborder since its origin ∼300 Ma. However, investigation of how this pair has co-evolved on a genomic level is limited to only a few host lineages. We sequenced the complete genomes of Sulcia and a betaproteobacterium from the treehopper, Entylia carinata (Membracidae: ENCA), as the first representative from this species-rich group. It also offers the opportunity to compare symbiont evolution across a major insect group, the Membracoidea (leafhoppers + treehoppers). Genomic analyses show that the betaproteobacteria in ENCA is a member of the Nasuia lineage. Both symbionts have larger genomes (Sulcia = 218 kb and Nasuia = 144 kb) than related lineages in Deltocephalinae leafhoppers, retaining genes involved in basic cellular functions and information processing. Nasuia-ENCA further exhibits few unique gene losses, suggesting that its parent lineage in the common ancestor to the Membracoidea was already highly reduced. Sulcia-ENCA has lost the abilities to synthesize menaquinone cofactor and to complete the synthesis of the branched-chain EAAs. Both capabilities are conserved in other Sulcia lineages sequenced from across the Auchenorrhyncha. Finally, metagenomic sequencing recovered the partial genome of an Arsenophonus symbiont, although it infects only 20% of individuals indicating a facultative role. © The Author 2017. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Exploring the relevance of autonomy and relatedness for mental health in healthy and depressed women from two different cultures: when does culture matter?

Science.gov (United States)

Balkir, Nazli; Arens, Elisabeth A; Barnow, Sven

2013-08-01

It is well known that the absence of both autonomy and social support (relatedness) are two important etiologic pathways to major depressive disorder (MDD). However, cross-cultural researchers state that the implications of autonomy and relatedness for mental health vary across cultures. To test these assumptions, the current study investigated the relevance of autonomy and relatedness for mental health in healthy and depressed women from two different cultures (Germans and Turkish immigrants in Germany). One hundred and eight (108) women were evaluated for their levels of autonomy/relatedness satisfaction, for overall psychopathological complaints including depression, for affectivity and for perceived loneliness through self-report measures. Among healthy groups, relatedness satisfaction predicted better mental health in Turkish women, whereas in German women, autonomy satisfaction was the better mental health predictor. Within depressed groups however, cultural differences in mental health outcomes regarding autonomy were no longer evident. Autonomy was associated with higher levels of mental health in Turkish as well as in German patients. Our findings indicate that the relationship between autonomy and mental health is culture-specific in healthy women, but disappears in depressed women. These findings are discussed with consideration of clinical implications and an outlook regarding further research.

Growth dynamics of the threatened Caribbean staghorn coral Acropora cervicornis: influence of host genotype, symbiont identity, colony size, and environmental setting.

Science.gov (United States)

Lirman, Diego; Schopmeyer, Stephanie; Galvan, Victor; Drury, Crawford; Baker, Andrew C; Baums, Iliana B

2014-01-01

The drastic decline in the abundance of Caribbean acroporid corals (Acropora cervicornis, A. palmata) has prompted the listing of this genus as threatened as well as the development of a regional propagation and restoration program. Using in situ underwater nurseries, we documented the influence of coral genotype and symbiont identity, colony size, and propagation method on the growth and branching patterns of staghorn corals in Florida and the Dominican Republic. Individual tracking of> 1700 nursery-grown staghorn fragments and colonies from 37 distinct genotypes (identified using microsatellites) in Florida and the Dominican Republic revealed a significant positive relationship between size and growth, but a decreasing rate of productivity with increasing size. Pruning vigor (enhanced growth after fragmentation) was documented even in colonies that lost 95% of their coral tissue/skeleton, indicating that high productivity can be maintained within nurseries by sequentially fragmenting corals. A significant effect of coral genotype was documented for corals grown in a common-garden setting, with fast-growing genotypes growing up to an order of magnitude faster than slow-growing genotypes. Algal-symbiont identity established using qPCR techniques showed that clade A (likely Symbiodinium A3) was the dominant symbiont type for all coral genotypes, except for one coral genotype in the DR and two in Florida that were dominated by clade C, with A- and C-dominated genotypes having similar growth rates. The threatened Caribbean staghorn coral is capable of extremely fast growth, with annual productivity rates exceeding 5 cm of new coral produced for every cm of existing coral. This species benefits from high fragment survivorship coupled by the pruning vigor experienced by the parent colonies after fragmentation. These life-history characteristics make A. cervicornis a successful candidate nursery species and provide optimism for the potential role that active propagation

Tapping the biotechnological potential of insect microbial symbionts: new insecticidal porphyrins

OpenAIRE

Martinez, Ana Fl?via Canovas; de Almeida, Lu?s Gustavo; Moraes, Luiz Alberto Beraldo; C?nsoli, Fernando Lu?s

2017-01-01

Background The demand for sustainable agricultural practices and the limited progress toward newer and safer chemicals for use in pest control maintain the impetus for research and identification of new natural molecules. Natural molecules are preferable to synthetic organic molecules because they are biodegradable, have low toxicity, are often selective and can be applied at low concentrations. Microbes are one source of natural insecticides, and microbial insect symbionts have attracted att...

Evolutionary relatedness does not predict competition and co-occurrence in natural or experimental communities of green algae

Science.gov (United States)

Alexandrou, Markos A.; Cardinale, Bradley J.; Hall, John D.; Delwiche, Charles F.; Fritschie, Keith; Narwani, Anita; Venail, Patrick A.; Bentlage, Bastian; Pankey, M. Sabrina; Oakley, Todd H.

2015-01-01

The competition-relatedness hypothesis (CRH) predicts that the strength of competition is the strongest among closely related species and decreases as species become less related. This hypothesis is based on the assumption that common ancestry causes close relatives to share biological traits that lead to greater ecological similarity. Although intuitively appealing, the extent to which phylogeny can predict competition and co-occurrence among species has only recently been rigorously tested, with mixed results. When studies have failed to support the CRH, critics have pointed out at least three limitations: (i) the use of data poor phylogenies that provide inaccurate estimates of species relatedness, (ii) the use of inappropriate statistical models that fail to detect relationships between relatedness and species interactions amidst nonlinearities and heteroskedastic variances, and (iii) overly simplified laboratory conditions that fail to allow eco-evolutionary relationships to emerge. Here, we address these limitations and find they do not explain why evolutionary relatedness fails to predict the strength of species interactions or probabilities of coexistence among freshwater green algae. First, we construct a new data-rich, transcriptome-based phylogeny of common freshwater green algae that are commonly cultured and used for laboratory experiments. Using this new phylogeny, we re-analyse ecological data from three previously published laboratory experiments. After accounting for the possibility of nonlinearities and heterogeneity of variances across levels of relatedness, we find no relationship between phylogenetic distance and ecological traits. In addition, we show that communities of North American green algae are randomly composed with respect to their evolutionary relationships in 99% of 1077 lakes spanning the continental United States. Together, these analyses result in one of the most comprehensive case studies of how evolutionary history influences

Adolescent Autonomy-Relatedness and the Family in Cultural Context: What Is Optimal?

Science.gov (United States)

Kagitcibasi, Cigdem

2013-01-01

This review examines self-family-culture links from a cultural and global perspective utilizing Kagitcibasi's Family Change Theory and Self Theory as general frameworks. These theories have the "autonomous-related self" at their point of intersection. Autonomy and relatedness dynamics is the key to understanding the self, and family…

Adaptation to nursing home: The role of leisure activities in light of motivation and relatedness.

Science.gov (United States)

Altintas, Emin; De Benedetto, Giorgio; Gallouj, Karim

Based on the motivational sequence described in Self-Determination Theory, this study explored the relationship between relatedness, motivation, adaptation and leisure in nursing homes. We formulated the hypothesis that the variables of the study would be found in an integrative mediational sequence: Participation in leisure activities→Relatedness→Self-determined motivation→Adaptation to nursing homes. Participants (N=112, mean age=84.17) were invited to complete questionnaires assessing these variables. Results of the path analysis found an unsatisfactory fit for this model but revealed another model (Model 2) with a good fit index: Relatedness→Participation in leisure activities→Self-determined motivation→Adaptation to nursing homes→Relatedness. Model 2 fitted better than model 1: the Chi-square values were not significant, Chi 2 (df=2)=5.1, p=0.078 and other indices were satisfactory (CFI=0.930, RMSEA=0.049 and NFI=0.918). These results suggest that feeling connected and secure in the relationships with others, and integrated as an individual to the group contribute to enhance leisure practice, self-determined motivation, and finally adaptation to life environment. Consequently, the relatedness promotes leisure activities practice which represents a central adaptive behavior in nursing homes. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

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

DEFF Research Database (Denmark)

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

2001-01-01

Transport mechanisms for transfer of nitrogen from the bacteroid side across the symbiosome membrane of pea (Pisum sativum L.) root nodules were identified by the use of energised bacteroid side-out symbiosome membrane vesicles. Such membrane vesicles were used to study a mechanism with high...... was not observed. The ammonium transporter has been identified as a voltage-driven channel whereas the symbiosome membrane aspartate transporter appears to be a H+/aspartate symport. The results suggest that nitrogen transfer between the symbionts in pea root nodules involves transfer of amino acids as well...... capacity for transport of ammonium and another mechanism capable of transporting aspartate. Both transport mechanisms are voltage driven and the rate of transport relates positively to the magnitude of the imposed membrane potentials. Competition for transport between ammonium and aspartate...

DREAM3: network inference using dynamic context likelihood of relatedness and the inferelator.

Directory of Open Access Journals (Sweden)

Aviv Madar

2010-03-01

Full Text Available Many current works aiming to learn regulatory networks from systems biology data must balance model complexity with respect to data availability and quality. Methods that learn regulatory associations based on unit-less metrics, such as Mutual Information, are attractive in that they scale well and reduce the number of free parameters (model complexity per interaction to a minimum. In contrast, methods for learning regulatory networks based on explicit dynamical models are more complex and scale less gracefully, but are attractive as they may allow direct prediction of transcriptional dynamics and resolve the directionality of many regulatory interactions.We aim to investigate whether scalable information based methods (like the Context Likelihood of Relatedness method and more explicit dynamical models (like Inferelator 1.0 prove synergistic when combined. We test a pipeline where a novel modification of the Context Likelihood of Relatedness (mixed-CLR, modified to use time series data is first used to define likely regulatory interactions and then Inferelator 1.0 is used for final model selection and to build an explicit dynamical model.Our method ranked 2nd out of 22 in the DREAM3 100-gene in silico networks challenge. Mixed-CLR and Inferelator 1.0 are complementary, demonstrating a large performance gain relative to any single tested method, with precision being especially high at low recall values. Partitioning the provided data set into four groups (knock-down, knock-out, time-series, and combined revealed that using comprehensive knock-out data alone provides optimal performance. Inferelator 1.0 proved particularly powerful at resolving the directionality of regulatory interactions, i.e. "who regulates who" (approximately of identified true positives were correctly resolved. Performance drops for high in-degree genes, i.e. as the number of regulators per target gene increases, but not with out-degree, i.e. performance is not affected by

Missing Links in Middle School: Developing Use of Disciplinary Relatedness in Evaluating Internet Search Results.

Directory of Open Access Journals (Sweden)

Frank C Keil

Full Text Available In the "digital native" generation, internet search engines are a commonly used source of information. However, adolescents may fail to recognize relevant search results when they are related in discipline to the search topic but lack other cues. Middle school students, high school students, and adults rated simulated search results for relevance to the search topic. The search results were designed to contrast deep discipline-based relationships with lexical similarity to the search topic. Results suggest that the ability to recognize disciplinary relatedness without supporting cues may continue to develop into high school. Despite frequent search engine usage, younger adolescents may require additional support to make the most of the information available to them.

Zooxanthellar symbionts shape host sponge trophic status through translocation of carbon.

Science.gov (United States)

Weisz, Jeremy B; Massaro, Andrew J; Ramsby, Blake D; Hill, Malcolm S

2010-12-01

Sponges belonging to the genus Cliona are common inhabitants of many coral reefs, and as bioeroders, they play an important role in the carbonate cycle of the reef. Several Cliona species maintain intracellular populations of dinoflagellate zooxanthellae (i.e., Symbiodinium spp.), which also form symbioses with a variety of other invertebrates and protists (e.g., corals, molluscs, foraminifera). Unlike the case of coral symbioses, however, almost nothing is known of the metabolic interaction between sponges and their zooxanthella symbionts. To assess this interaction, we performed a tracer experiment to follow C and N in the system, performed a reciprocal transplant experiment, and measured the stable carbon isotope ratio of Cliona spp. with and without zooxanthellae to study the influence of environment on the interaction. We found strong evidence of a transfer of C from zooxanthellae to their sponge hosts but no evidence of a transfer of N from sponge to zooxanthellae. We also saw significant influences of the environment on the metabolism of the sponges. Finally, we observed significant differences in carbon metabolism of sponge species with and without symbionts. These data strongly support hypotheses of metabolic integration between zooxanthellae and their sponge host and extend our understanding of basic aspects of benthic-pelagic coupling in shallow-water marine environments.

Genetic Diversity of Nostoc Symbionts Endophytically Associated with Two Bryophyte Species

OpenAIRE

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

2001-01-01

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

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

Science.gov (United States)

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

2014-01-01

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

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

Directory of Open Access Journals (Sweden)

Eunsoo Kim

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

A/r/tographic Collaboration as Radical Relatedness

Directory of Open Access Journals (Sweden)

Barbara Bickel PhD

2011-03-01

Full Text Available In this paper the authors examine a/r/tographical collaboration in a community-engaged research study investigating immigrant understandings of home and place. The study, The City of Richgate, involves a complex collaboration between community members, community organizations, educational institutions, and a research team comprising artist-educators. The study crosses border zones of cultural, ethnic, geographic, institutional, public, private, and disciplinary boundaries, reflecting the ever-changing character of postmodern reality. In this paper the authors reflect critically and theoretically on the lived experience of radical relatedness found within the complex collaboration, particularly within the a/r/tographic research team. This offers a qualitative methodology of radical collaboration applicable to many fields of inquiry in the academy, art world, and community.

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

Science.gov (United States)

Overstreet, Robin M.

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

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

Czech Academy of Sciences Publication Activity Database

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

2013-01-01

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

Bacterial Symbionts in Lepidoptera: Their Diversity, Transmission, and Impact on the Host

Directory of Open Access Journals (Sweden)

Luis R. Paniagua Voirol

2018-03-01

Full Text Available The insect’s microbiota is well acknowledged as a “hidden” player influencing essential insect traits. The gut microbiome of butterflies and moths (Lepidoptera has been shown to be highly variable between and within species, resulting in a controversy on the functional relevance of gut microbes in this insect order. Here, we aim to (i review current knowledge on the composition of gut microbial communities across Lepidoptera and (ii elucidate the drivers of the variability in the lepidopteran gut microbiome and provide an overview on (iii routes of transfer and (iv the putative functions of microbes in Lepidoptera. To find out whether Lepidopterans possess a core gut microbiome, we compared studies of the microbiome from 30 lepidopteran species. Gut bacteria of the Enterobacteriaceae, Bacillaceae, and Pseudomonadaceae families were the most widespread across species, with Pseudomonas, Bacillus, Staphylococcus, Enterobacter, and Enterococcus being the most common genera. Several studies indicate that habitat, food plant, and age of the host insect can greatly impact the gut microbiome, which contributes to digestion, detoxification, or defense against natural enemies. We mainly focus on the gut microbiome, but we also include some examples of intracellular endosymbionts. These symbionts are present across a broad range of insect taxa and are known to exert different effects on their host, mostly including nutrition and reproductive manipulation. Only two intracellular bacteria genera (Wolbachia and Spiroplasma have been reported to colonize reproductive tissues of Lepidoptera, affecting their host’s reproduction. We explore routes of transmission of both gut microbiota and intracellular symbionts and have found that these microbes may be horizontally transmitted through the host plant, but also vertically via the egg stage. More detailed knowledge about the functions and plasticity of the microbiome in Lepidoptera may provide novel leads

Sperm competitive ability and genetic relatedness in Drosophila melanogaster: similarity breeds contempt.

Science.gov (United States)

Mack, Paul D; Hammock, Brian A; Promislow, Daniel E L

2002-09-01

Offspring of close relatives often suffer severe fitness consequences. Previous studies have demonstrated that females, when given a choice, will choose to avoid mating with closely related males. But where opportunities for mate choice are limited or kin recognition is absent, precopulatory mechanisms may not work. In this case, either sex could reduce the risks of inbreeding through mechanisms that occur during or after copulation. During mating, males or females could commit fewer gametes when mating with a close relative. After mating, females could offset the effects of mating with a closely related male through cryptic choice. Few prior studies of sperm competition have examined the effect of genetic similarity, however, and what studies do exist have yielded equivocal results. In an effort to resolve this issue, we measured the outcome of sperm competition when female Drosophila melanogaster were mated to males of four different degrees of genetic relatedness and then to a standardized competitor. We provide the strongest evidence to date that sperm competitive ability is negatively correlated with relatedness, even after controlling for inbreeding depression.

Rival male relatedness does not affect ejaculate allocation as predicted by sperm competition theory.

Directory of Open Access Journals (Sweden)

Melissa L Thomas

Full Text Available When females are sexually promiscuous, the intensity of sperm competition for males depends on how many partners females mate with. To maximize fitness, males should adjust their copulatory investment in relation to this intensity. However, fitness costs associated with sperm competition may not only depend on how many males a female has mated with, but also how related rival males are. According to theoretical predictions, males should adjust their copulatory investment in response to the relatedness of their male rival, and transfer more sperm to females that have first mated with a non-sibling male than females that have mated to a related male. Here, for the first time, we empirically test this theory using the Australian field cricket Teleogryllus oceanicus. We expose male crickets to sperm competition from either a full sibling or non-sibling male, by using both the presence of a rival male and the rival male's actual competing ejaculate as cues. Contrary to predictions, we find that males do not adjust ejaculates in response to the relatedness of their male rival. Instead, males with both full-sibling and non-sibling rivals allocate sperm of similar quality to females. This lack of kin biased behaviour is independent of any potentially confounding effect of strong competition between close relatives; kin biased behaviour was absent irrespective of whether males were raised in full sibling or mixed relatedness groups.

Environmentally Active People: The Role of Autonomy, Relatedness, Competence and Self-Determined Motivation

Science.gov (United States)

Cooke, Anna N.; Fielding, Kelly S.; Louis, Winnifred R.

2016-01-01

To identify pathways to lower environmental impacts, this research examined the motivation and antecedents of motivation (autonomy, relatedness, competence), of environmentally active people. Previous research suggests that people with more self-determined motivation for pro-environmental behavior (PEB) should carry out more PEBs, and have lower…

Exploring the Influence of Nature Relatedness and Perceived Science Knowledge on Proenvironmental Behavior

Science.gov (United States)

Obery, Amanda; Bangert, Arthur

2017-01-01

This study was undertaken to investigate the factors influencing proenvironmental behavior of individuals residing in the Northern Rocky Mountains (N = 267). Measures of relatedness to nature and perceived science knowledge were collected through a convenience sample approach using multiple avenues such as city email lists, organizational…

Professional Well-Being of Practicing Physicians: The Roles of Autonomy, Competence, and Relatedness.

Science.gov (United States)

Babenko, Oksana

2018-02-02

This study investigated the roles of basic psychological needs-autonomy, competence, and relatedness-in physicians' professional well-being, specifically satisfaction with professional life, work-related engagement, and exhaustion. Using an online survey, quantitative data were collected from 57 practicing physicians. Overall, 65% of the participants were female; 49% were family medicine (FM) physicians, with the rest of the participants practicing in various non-FM specialties (e.g., internal medicine, pediatrics, surgery); and 47% were in the early-career stage (≤10 years in practice). Multivariate regression analyses indicated that of the three psychological needs, the need for relatedness had the largest unique contributions to physicians' satisfaction with professional life, work-related engagement, and exhaustion, respectively. The unique contributions of the needs for autonomy and competence were relatively small. These findings extend basic psychological needs theory to the work domain of practicing physicians in an attempt to examine underpinnings of physicians' professional well-being, a critical component of quality patient care.

The inadequacy of morphology for species and genus delineation in microbial eukaryotes: an example from the parabasalian termite symbiont coronympha.

Directory of Open Access Journals (Sweden)

James T Harper

Full Text Available BACKGROUND: For the majority of microbial eukaryotes (protists, algae, there is no clearly superior species concept that is consistently applied. In the absence of a practical biological species concept, most species and genus level delineations have historically been based on morphology, which may lead to an underestimate of the diversity of microbial eukaryotes. Indeed, a growing body of molecular evidence, such as barcoding surveys, is beginning to support the conclusion that significant cryptic species diversity exists. This underestimate of diversity appears to be due to a combination of using morphology as the sole basis for assessing diversity and our inability to culture the vast majority of microbial life. Here we have used molecular markers to assess the species delineations in two related but morphologically distinct genera of uncultivated symbionts found in the hindgut of termites. METHODOLOGY/PRINCIPAL FINDINGS: Using single-cell isolation and environmental PCR, we have used a barcoding approach to characterize the diversity of Coronympha and Metacoronympha symbionts in four species of Incisitermes termites, which were also examined using scanning electron microscopy and light microcopy. Despite the fact that these genera are significantly different in morphological complexity and structural organisation, we find they are two life history stages of the same species. At the same time, we show that the symbionts from different termite hosts show an equal or greater level of sequence diversity than do the hosts, despite the fact that the symbionts are all classified as one species. CONCLUSIONS/SIGNIFICANCE: The morphological information used to describe the diversity of these microbial symbionts is misleading at both the genus and species levels, and led to an underestimate of species level diversity as well as an overestimate of genus level diversity. The genus 'Metacoronympha' is invalid and appears to be a life history stage of

Laccase detoxification mediates the nutritional alliance between leaf-cutting ants and fungus-garden symbionts.

Science.gov (United States)

De Fine Licht, Henrik H; Schiøtt, Morten; Rogowska-Wrzesinska, Adelina; Nygaard, Sanne; Roepstorff, Peter; Boomsma, Jacobus J

2013-01-08

Leaf-cutting ants combine large-scale herbivory with fungus farming to sustain advanced societies. Their stratified colonies are major evolutionary achievements and serious agricultural pests, but the crucial adaptations that allowed this mutualism to become the prime herbivorous component of neotropical ecosystems has remained elusive. Here we show how coevolutionary adaptation of a specific enzyme in the fungal symbiont has helped leaf-cutting ants overcome plant defensive phenolic compounds. We identify nine putative laccase-coding genes in the fungal genome of Leucocoprinus gongylophorus cultivated by the leaf-cutting ant Acromyrmex echinatior. One of these laccases (LgLcc1) is highly expressed in the specialized hyphal tips (gongylidia) that the ants preferentially eat, and we confirm that these ingested laccase molecules pass through the ant guts and remain active when defecated on the leaf pulp that the ants add to their gardens. This accurate deposition ensures that laccase activity is highest where new leaf material enters the fungus garden, but where fungal mycelium is too sparse to produce extracellular enzymes in sufficient quantities to detoxify phenolic compounds. Phylogenetic analysis of LgLcc1 ortholog sequences from symbiotic and free-living fungi revealed significant positive selection in the ancestral lineage that gave rise to the gongylidia-producing symbionts of leaf-cutting ants and their non-leaf-cutting ant sister group. Our results are consistent with fungal preadaptation and subsequent modification of a particular laccase enzyme for the detoxification of secondary plant compounds during the transition to active herbivory in the ancestor of leaf-cutting ants between 8 and 12 Mya.

Draft Genomes, Phylogenetic Reconstruction, and Comparative Genomics of Two Novel Cohabiting Bacterial Symbionts Isolated from Frankliniella occidentalis.

Science.gov (United States)

Facey, Paul D; Méric, Guillaume; Hitchings, Matthew D; Pachebat, Justin A; Hegarty, Matt J; Chen, Xiaorui; Morgan, Laura V A; Hoeppner, James E; Whitten, Miranda M A; Kirk, William D J; Dyson, Paul J; Sheppard, Sam K; Del Sol, Ricardo

2015-07-15

Obligate bacterial symbionts are widespread in many invertebrates, where they are often confined to specialized host cells and are transmitted directly from mother to progeny. Increasing numbers of these bacteria are being characterized but questions remain about their population structure and evolution. Here we take a comparative genomics approach to investigate two prominent bacterial symbionts (BFo1 and BFo2) isolated from geographically separated populations of western flower thrips, Frankliniella occidentalis. Our multifaceted approach to classifying these symbionts includes concatenated multilocus sequence analysis (MLSA) phylogenies, ribosomal multilocus sequence typing (rMLST), construction of whole-genome phylogenies, and in-depth genomic comparisons. We showed that the BFo1 genome clusters more closely to species in the genus Erwinia, and is a putative close relative to Erwinia aphidicola. BFo1 is also likely to have shared a common ancestor with Erwinia pyrifoliae/Erwinia amylovora and the nonpathogenic Erwinia tasmaniensis and genetic traits similar to Erwinia billingiae. The BFo1 genome contained virulence factors found in the genus Erwinia but represented a divergent lineage. In contrast, we showed that BFo2 belongs within the Enterobacteriales but does not group closely with any currently known bacterial species. Concatenated MLSA phylogenies indicate that it may have shared a common ancestor to the Erwinia and Pantoea genera, and based on the clustering of rMLST genes, it was most closely related to Pantoea ananatis but represented a divergent lineage. We reconstructed a core genome of a putative common ancestor of Erwinia and Pantoea and compared this with the genomes of BFo bacteria. BFo2 possessed none of the virulence determinants that were omnipresent in the Erwinia and Pantoea genera. Taken together, these data are consistent with BFo2 representing a highly novel species that maybe related to known Pantoea. © The Author(s) 2015. Published by

Multibusiness firms and performance in Italy. What role does relatedness play?

OpenAIRE

Maurizio La Rocca; Tiziana La Rocca; F. Javier Sánchez Vidal

2018-01-01

This paper evaluates the effect of diversification strategy on corporate value for a sample of Italian companies. It accounts for both the level of diversification and relatedness components. Empirical analyses show a U-shaped curvilinear relationship between diversification and value. In contrast to the mainstream literature, our results highlight that related diversification has a negative effect, while unrelated diversification is a value-creating strategy. JEL classification: L25, M10, K...

Antagonistic interactions between honey bee bacterial symbionts and implications for disease

Directory of Open Access Journals (Sweden)

Armstrong Tamieka-Nicole

2006-03-01

Full Text Available Abstract Background Honey bees, Apis mellifera, face many parasites and pathogens and consequently rely on a diverse set of individual and group-level defenses to prevent disease. One route by which honey bees and other insects might combat disease is through the shielding effects of their microbial symbionts. Bees carry a diverse assemblage of bacteria, very few of which appear to be pathogenic. Here we explore the inhibitory effects of these resident bacteria against the primary bacterial pathogen of honey bees, Paenibacillus larvae. Results Here we isolate, culture, and describe by 16S rRNA and protein-coding gene sequences 61 bacterial isolates from honey bee larvae, reflecting a total of 43 distinct bacterial taxa. We culture these bacteria alongside the primary larval pathogen of honey bees, Paenibacillus larvae, and show that many of these isolates severely inhibit the growth of this pathogen. Accordingly, symbiotic bacteria including those described here are plausible natural antagonists toward this widespread pathogen. Conclusion The results suggest a tradeoff in social insect colonies between the maintenance of potentially beneficial bacterial symbionts and deterrence at the individual and colony level of pathogenic species. They also provide a novel mechanism for recently described social components behind disease resistance in insect colonies, and point toward a potential control strategy for an important bee disease.

Diversity and distribution of entomopathogenic nematodes (Nematoda: Steinernematidae, Heterorhabditidae) and their bacterial symbionts (gamma-Proteobacteria: Enterobacteriaceae) in Jordan.

Science.gov (United States)

Stock, S Patricia; Al Banna, Luma; Darwish, Rula; Katbeh, Ahmad

2008-06-01

Until now, only a few systematic surveys of entomopathogenic nematodes (EPN) have been conducted in Middle Eastern countries. Many of the recovered EPN species in this region have shown to own distinctive qualities that enable their survival in unique environments, such as high temperatures and low moisture levels tolerance. These new species and strains, with unique environmental tolerances, are more suitable for their consideration in pest management programs in xerophytic regions. With this background in mind, we recently conducted a survey of EPN in Jordan. This study records for the first time the diversity and distribution of these nematodes and their bacterial symbionts in this country. Jordan's three geographic regions: (1) the highlands, (2) Jordan valley and (3) the desert region were sampled. Within each region, natural habitats and agricultural regions characteristic to each region were considered for sampling purposes. Four EPN species including three Steinernema and one Heterorhabditis were recovered. Nematodes were identified using a combination of molecular markers and classic morphological diagnostic tools. Bacterial symbionts were identified by analysis of 16S rRNA sequences. Abiotic characteristics such as soil type, soil pH, and elevation were also recorded. We herein report the diversity of EPN species in Jordan and discuss their potential in Biocontrol and IPM programs for this country.

Toward a better understanding of the mechanisms of symbiosis: a comprehensive proteome map of a nascent insect symbiont.

Science.gov (United States)

Renoz, François; Champagne, Antoine; Degand, Hervé; Faber, Anne-Marie; Morsomme, Pierre; Foray, Vincent; Hance, Thierry

2017-01-01

Symbiotic bacteria are common in insects and can affect various aspects of their hosts' biology. Although the effects of insect symbionts have been clarified for various insect symbiosis models, due to the difficulty of cultivating them in vitro , there is still limited knowledge available on the molecular features that drive symbiosis. Serratia symbiotica is one of the most common symbionts found in aphids. The recent findings of free-living strains that are considered as nascent partners of aphids provide the opportunity to examine the molecular mechanisms that a symbiont can deploy at the early stages of the symbiosis (i.e., symbiotic factors). In this work, a proteomic approach was used to establish a comprehensive proteome map of the free-living S. symbiotica strain CWBI-2.3 T . Most of the 720 proteins identified are related to housekeeping or primary metabolism. Of these, 76 were identified as candidate proteins possibly promoting host colonization. Our results provide strong evidence that S. symbiotica CWBI-2.3 T is well-armed for invading insect host tissues, and suggest that certain molecular features usually harbored by pathogenic bacteria are no longer present. This comprehensive proteome map provides a series of candidate genes for further studies to understand the molecular cross-talk between insects and symbiotic bacteria.

Toward a better understanding of the mechanisms of symbiosis: a comprehensive proteome map of a nascent insect symbiont

Directory of Open Access Journals (Sweden)

François Renoz

2017-05-01

Full Text Available Symbiotic bacteria are common in insects and can affect various aspects of their hosts’ biology. Although the effects of insect symbionts have been clarified for various insect symbiosis models, due to the difficulty of cultivating them in vitro, there is still limited knowledge available on the molecular features that drive symbiosis. Serratia symbiotica is one of the most common symbionts found in aphids. The recent findings of free-living strains that are considered as nascent partners of aphids provide the opportunity to examine the molecular mechanisms that a symbiont can deploy at the early stages of the symbiosis (i.e., symbiotic factors. In this work, a proteomic approach was used to establish a comprehensive proteome map of the free-living S. symbiotica strain CWBI-2.3T. Most of the 720 proteins identified are related to housekeeping or primary metabolism. Of these, 76 were identified as candidate proteins possibly promoting host colonization. Our results provide strong evidence that S. symbiotica CWBI-2.3T is well-armed for invading insect host tissues, and suggest that certain molecular features usually harbored by pathogenic bacteria are no longer present. This comprehensive proteome map provides a series of candidate genes for further studies to understand the molecular cross-talk between insects and symbiotic bacteria.

The effect of relatedness on the response of Adalia bipunctata L. to oviposition deterring cues

Czech Academy of Sciences Publication Activity Database

Martini, X.; Dixon, Anthony F. G.; Hemptinne, J. L.

2013-01-01

Roč. 103, č. 1 (2013), s. 14-19 ISSN 0007-4853 Institutional support: RVO:67179843 Keywords : Coccinellidae * relatedness * kin * larval tracks * oviposition deterring pheromone Subject RIV: EH - Ecology, Behaviour Impact factor: 1.895, year: 2013

Antigenic relatedness of primate procollagens as determined by a competitive radioimmunoassay

International Nuclear Information System (INIS)

Taubman, M.B.; Goldberg, B.

1978-01-01

A radioimmunoassay specific for the nonhelical carboxy terminal portion of human type I procollagen was used to study the antigenic relatedness of primate procollagens. The assay identified reactive antigen in primate sera and in the media of primate fibroblast cultures. The displacement curves generated in the assay indicated that human and ape type I procollagens have antigenically identical carboxy terminal determinants which are partially cross-reactive with those from Old and New World monkeys. (author)

The uncultured luminous symbiont of Anomalops katoptron (Beryciformes: Anomalopidae) represents a new bacterial genus.

Science.gov (United States)

Hendry, Tory A; Dunlap, Paul V

2011-12-01

Flashlight fishes (Beryciformes: Anomalopidae) harbor luminous symbiotic bacteria in subocular light organs and use the bacterial light for predator avoidance, feeding, and communication. Despite many attempts anomalopid symbionts have not been brought into laboratory culture, which has restricted progress in understanding their phylogenetic relationships with other luminous bacteria, identification of the genes of their luminescence system, as well as the nature of their symbiotic interactions with their fish hosts. To begin addressing these issues, we used culture-independent analysis of the bacteria symbiotic with the anomalopid fish, Anomalops katoptron, to characterize the phylogeny of the bacteria and to identify the genes of their luminescence system including those involved in the regulation of luminescence. Analysis of the 16S rRNA, atpA, gapA, gyrB, pyrH, recA, rpoA, and topA genes resolved the A. katoptron symbionts as a clade nested within and deeply divergent from other members of Vibrionaceae. The bacterial luminescence (lux) genes were identified as a contiguous set (luxCDABEG), as found for the lux operons of other luminous bacteria. Phylogenetic analysis based on the lux genes confirmed the housekeeping gene phylogenetic placement. Furthermore, genes flanking the lux operon in the A. katoptron symbionts differed from those flanking lux operons of other genera of luminous bacteria. We therefore propose the candidate name Candidatus Photodesmus (Greek: photo = light, desmus = servant) katoptron for the species of bacteria symbiotic with A. katoptron. Results of a preliminary genomic analysis for genes regulating luminescence in other bacteria identified only a Vibrio harveyi-type luxR gene. These results suggest that expression of the luminescence system might be continuous in P. katoptron. Copyright © 2011 Elsevier Inc. All rights reserved.

The dominant detritus-feeding invertebrate in Arctic peat soils derives its essential amino acids from gut symbionts

DEFF Research Database (Denmark)

Larsen, Thomas; Ventura, Marc; Maraldo, Kristine

2016-01-01

insufficiencies of macronutrients such as essential amino acids (EAA). Documenting whether gut symbionts also function as partners for symbiotic EAA supplementation is important because the question of how some detritivores are able to subsist on nutritionally insufficient diets has remained unresolved. 3....... To answer this poorly understood nutritional aspect of symbiont-host interactions, we studied the enchytraeid worm, a bulk soil feeder that thrives in Arctic peatlands. In a combined field and laboratory study, we employed stable isotope fingerprinting of amino acids to identify the biosynthetic origins...... of amino acids to bacteria, fungi and plants in enchytraeids. 4. Enchytraeids collected from Arctic peatlands derived more than 80% of their EAA from bacteria. In a controlled feeding study with the enchytraeid Enchytraeus crypticus, EAA derived almost exclusively from gut bacteria when the worms fed...

Growth dynamics of the threatened Caribbean staghorn coral Acropora cervicornis: influence of host genotype, symbiont identity, colony size, and environmental setting.

Directory of Open Access Journals (Sweden)

Diego Lirman

Full Text Available BACKGROUND: The drastic decline in the abundance of Caribbean acroporid corals (Acropora cervicornis, A. palmata has prompted the listing of this genus as threatened as well as the development of a regional propagation and restoration program. Using in situ underwater nurseries, we documented the influence of coral genotype and symbiont identity, colony size, and propagation method on the growth and branching patterns of staghorn corals in Florida and the Dominican Republic. METHODOLOGY/PRINCIPAL FINDINGS: Individual tracking of> 1700 nursery-grown staghorn fragments and colonies from 37 distinct genotypes (identified using microsatellites in Florida and the Dominican Republic revealed a significant positive relationship between size and growth, but a decreasing rate of productivity with increasing size. Pruning vigor (enhanced growth after fragmentation was documented even in colonies that lost 95% of their coral tissue/skeleton, indicating that high productivity can be maintained within nurseries by sequentially fragmenting corals. A significant effect of coral genotype was documented for corals grown in a common-garden setting, with fast-growing genotypes growing up to an order of magnitude faster than slow-growing genotypes. Algal-symbiont identity established using qPCR techniques showed that clade A (likely Symbiodinium A3 was the dominant symbiont type for all coral genotypes, except for one coral genotype in the DR and two in Florida that were dominated by clade C, with A- and C-dominated genotypes having similar growth rates. CONCLUSION/SIGNIFICANCE: The threatened Caribbean staghorn coral is capable of extremely fast growth, with annual productivity rates exceeding 5 cm of new coral produced for every cm of existing coral. This species benefits from high fragment survivorship coupled by the pruning vigor experienced by the parent colonies after fragmentation. These life-history characteristics make A. cervicornis a successful candidate

Does relatedness of natives used for soil conditioning influence plant-soil feedback of exotics?

Czech Academy of Sciences Publication Activity Database

Dostál, Petr; Plačková, M.

2011-01-01

Roč. 13, č. 2 (2011), s. 331-340 ISSN 1387-3547 R&D Projects: GA AV ČR KJB600050713 Institutional research plan: CEZ:AV0Z60050516 Keywords : phylogenetic relatedness * plant invasions * soil microbiota Subject RIV: EF - Botanics Impact factor: 2.896, year: 2011

[Influence of autonomy support, social goals and relatedness on amotivation in physical education classes].

Science.gov (United States)

Moreno Murcia, Juan A; Parra Rojas, Nicolás; González-Cutre Coll, David

2008-11-01

The purpose of this study was to analyze some factors that influence amotivation in physical education classes. A sample of 399 students, of ages 14 to 16 years, was used. They completed the Perceived Autonomy Support Scale in Exercise Settings (PASSES), the Social Goal Scale-Physical Education (SGS-PE), the factor of the Basic Psychological Needs in Exercise Scale (BPNES) adapted to physical education and the amotivation> factor of the Perceived Locus of Causality Scale (PLOC). The psychometric properties of the PASSES were analyzed, as this scale had not been validated to the Spanish context. In this analysis, the scale showed appropriate validity and reliability. The results of the structural equation model indicated that social responsibility and social relationship goals positively predicted perception of relatedness, whereas the context of autonomy support did not significantly predict it. In turn, perception of relatedness negatively predicted amotivation. The findings are discussed with regard to enhancing students' positive motivation.

Wolbachia symbiont infections induce strong cytoplasmic incompatibility in the tsetse fly Glossina morsitans.

Directory of Open Access Journals (Sweden)

Uzma Alam

2011-12-01

Full Text Available Tsetse flies are vectors of the protozoan parasite African trypanosomes, which cause sleeping sickness disease in humans and nagana in livestock. Although there are no effective vaccines and efficacious drugs against this parasite, vector reduction methods have been successful in curbing the disease, especially for nagana. Potential vector control methods that do not involve use of chemicals is a genetic modification approach where flies engineered to be parasite resistant are allowed to replace their susceptible natural counterparts, and Sterile Insect technique (SIT where males sterilized by chemical means are released to suppress female fecundity. The success of genetic modification approaches requires identification of strong drive systems to spread the desirable traits and the efficacy of SIT can be enhanced by identification of natural mating incompatibility. One such drive mechanism results from the cytoplasmic incompatibility (CI phenomenon induced by the symbiont Wolbachia. CI can also be used to induce natural mating incompatibility between release males and natural populations. Although Wolbachia infections have been reported in tsetse, it has been a challenge to understand their functional biology as attempts to cure tsetse of Wolbachia infections by antibiotic treatment damages the obligate mutualistic symbiont (Wigglesworthia, without which the flies are sterile. Here, we developed aposymbiotic (symbiont-free and fertile tsetse lines by dietary provisioning of tetracycline supplemented blood meals with yeast extract, which rescues Wigglesworthia-induced sterility. Our results reveal that Wolbachia infections confer strong CI during embryogenesis in Wolbachia-free (Gmm(Apo females when mated with Wolbachia-infected (Gmm(Wt males. These results are the first demonstration of the biological significance of Wolbachia infections in tsetse. Furthermore, when incorporated into a mathematical model, our results confirm that Wolbachia can

Genetic relatedness among indigenous rice varieties in the Eastern Himalayan region based on nucleotide sequences of the Waxy gene.

Science.gov (United States)

Choudhury, Baharul I; Khan, Mohammed L; Dayanandan, Selvadurai

2014-12-29

Indigenous rice varieties in the Eastern Himalayan region of Northeast India are traditionally classified into sali, boro and jum ecotypes based on geographical locality and the season of cultivation. In this study, we used DNA sequence data from the Waxy (Wx) gene to infer the genetic relatedness among indigenous rice varieties in Northeast India and to assess the genetic distinctiveness of ecotypes. The results of all three analyses (Bayesian, Maximum Parsimony and Neighbor Joining) were congruent and revealed two genetically distinct clusters of rice varieties in the region. The large group comprised several varieties of sali and boro ecotypes, and all agronomically improved varieties. The small group consisted of only traditionally cultivated indigenous rice varieties, which included one boro, few sali and all jum varieties. The fixation index analysis revealed a very low level of differentiation between sali and boro (F(ST) = 0.005), moderate differentiation between sali and jum (F(ST) = 0.108) and high differentiation between jum and boro (F(ST) = 0.230) ecotypes. The genetic relatedness analyses revealed that sali, boro and jum ecotypes are genetically heterogeneous, and the current classification based on cultivation type is not congruent with the genetic background of rice varieties. Indigenous rice varieties chosen from genetically distinct clusters could be used in breeding programs to improve genetic gain through heterosis, while maintaining high genetic diversity.

Endophytic life strategies decoded by genome and transcriptome analyses of the mutualistic root symbiont Piriformospora indica.

Directory of Open Access Journals (Sweden)

Alga Zuccaro

2011-10-01

Full Text Available Recent sequencing projects have provided deep insight into fungal lifestyle-associated genomic adaptations. Here we report on the 25 Mb genome of the mutualistic root symbiont Piriformospora indica (Sebacinales, Basidiomycota and provide a global characterization of fungal transcriptional responses associated with the colonization of living and dead barley roots. Extensive comparative analysis of the P. indica genome with other Basidiomycota and Ascomycota fungi that have diverse lifestyle strategies identified features typically associated with both, biotrophism and saprotrophism. The tightly controlled expression of the lifestyle-associated gene sets during the onset of the symbiosis, revealed by microarray analysis, argues for a biphasic root colonization strategy of P. indica. This is supported by a cytological study that shows an early biotrophic growth followed by a cell death-associated phase. About 10% of the fungal genes induced during the biotrophic colonization encoded putative small secreted proteins (SSP, including several lectin-like proteins and members of a P. indica-specific gene family (DELD with a conserved novel seven-amino acids motif at the C-terminus. Similar to effectors found in other filamentous organisms, the occurrence of the DELDs correlated with the presence of transposable elements in gene-poor repeat-rich regions of the genome. This is the first in depth genomic study describing a mutualistic symbiont with a biphasic lifestyle. Our findings provide a significant advance in understanding development of biotrophic plant symbionts and suggest a series of incremental shifts along the continuum from saprotrophy towards biotrophy in the evolution of mycorrhizal association from decomposer fungi.

Interpersonal Relatedness and Self-Definition in Normal and Disrupted Personality Development: Retrospect and Prospect

Science.gov (United States)

Luyten, Patrick; Blatt, Sidney J.

2013-01-01

Two-polarities models of personality propose that personality development evolves through a dialectic synergistic interaction between two fundamental developmental psychological processes across the life span--the development of interpersonal relatedness on the one hand and of self-definition on the other. This article offers a broad review of…

Coral bleaching is linked to the capacity of the animal host to supply essential metals to the symbionts.

Science.gov (United States)

Ferrier-Pagès, Christine; Sauzéat, Lucie; Balter, Vincent

2018-03-23

Massive coral bleaching events result in extensive coral loss throughout the world. These events are mainly caused by seawater warming, but are exacerbated by the subsequent decrease in nutrient availability in surface waters. It has therefore been shown that nitrogen, phosphorus or iron limitation contribute to the underlying conditions by which thermal stress induces coral bleaching. Generally, information on the trophic ecology of trace elements (micronutrients) in corals, and on how they modulate the coral response to thermal stress is lacking. Here, we demonstrate for the first time that heterotrophic feeding (i.e. the capture of zooplankton prey by the coral host) and thermal stress induce significant changes in micro element concentrations and isotopic signatures of the scleractinian coral Stylophora pistillata. The results obtained first reveal that coral symbionts are the major sink for the heterotrophically acquired micronutrients and accumulate manganese, magnesium and iron from the food. These metals are involved in photosynthesis and antioxidant protection. In addition, we show that fed corals can maintain high micronutrient concentrations in the host tissue during thermal stress and do not bleach, whereas unfed corals experience a significant decrease in copper, zinc, boron, calcium and magnesium in the host tissue and bleach. In addition, the significant increase in δ 65 Cu and δ 66 Zn signature of symbionts and host tissue at high temperature suggests that these isotopic compositions are good proxy for stress in corals. Overall, present findings highlight a new way in which coral heterotrophy and micronutrient availability contribute to coral resistance to global warming and bleaching. © 2018 John Wiley & Sons Ltd.

Discordant coral-symbiont structuring: factors shaping geographical variation of Symbiodinium communities in a facultative zooxanthellate coral genus, Oculina

Science.gov (United States)

Leydet, Karine Posbic; Hellberg, Michael E.

2016-06-01

Understanding the factors that help shape the association between corals and their algal symbionts, zooxanthellae ( Symbiodinium), is necessary to better understand the functional diversity and acclimatization potential of the coral host. However, most studies focus on tropical zooxanthellate corals and their obligate algal symbionts, thus limiting our full comprehension of coral-algal symbiont associations. Here, we examine algal associations in a facultative zooxanthellate coral. We survey the Symbiodinium communities associated with Oculina corals in the western North Atlantic and the Mediterranean using one clade-level marker ( psbA coding region) and three fine-scale markers ( cp23S- rDNA, b7sym15 flanking region, and b2sym17). We ask whether Oculina spp. harbor geographically different Symbiodinium communities across their geographic range and, if so, whether the host's genetics or habitat differences are correlated with this geographical variation. We found that Oculina corals harbor different Symbiodinium communities across their geographical range. Of the habitat differences (including chlorophyll a concentration and depth), sea surface temperature is better correlated with this geographical variation than the host's genetics, a pattern most evident in the Mediterranean. Our results suggest that although facultative zooxanthellate corals may be less dependent on their algal partners compared to obligate zooxanthellate corals, the Symbiodinium communities that they harbor may nevertheless reflect acclimatization to environmental variation among habitats.

Phylogenetic Analysis of Shewanella Strains by DNA Relatedness Derived from Whole Genome Microarray DNA-DNA Hybridization and Comparisons with Other Methods

International Nuclear Information System (INIS)

Wu, Liyou; Yi, T.Y.; Van Nostrand, Joy; Zhou, Jizhong

2010-01-01

Phylogenetic analyses were done for the Shewanella strains isolated from Baltic Sea (38 strains), US DOE Hanford Uranium bioremediation site (Hanford Reach of the Columbia River (HRCR), 11 strains), Pacific Ocean and Hawaiian sediments (8 strains), and strains from other resources (16 strains) with three out group strains, Rhodopseudomonas palustris, Clostridium cellulolyticum, and Thermoanaerobacter ethanolicus X514, using DNA relatedness derived from WCGA-based DNA-DNA hybridizations, sequence similarities of 16S rRNA gene and gyrB gene, and sequence similarities of 6 loci of Shewanella genome selected from a shared gene list of the Shewanella strains with whole genome sequenced based on the average nucleotide identity of them (ANI). The phylogenetic trees based on 16S rRNA and gyrB gene sequences, and DNA relatedness derived from WCGA hybridizations of the tested Shewanella strains share exactly the same sub-clusters with very few exceptions, in which the strains were basically grouped by species. However, the phylogenetic analysis based on DNA relatedness derived from WCGA hybridizations dramatically increased the differentiation resolution at species and strains level within Shewanella genus. When the tree based on DNA relatedness derived from WCGA hybridizations was compared to the tree based on the combined sequences of the selected functional genes (6 loci), we found that the resolutions of both methods are similar, but the clustering of the tree based on DNA relatedness derived from WMGA hybridizations was clearer. These results indicate that WCGA-based DNA-DNA hybridization is an idea alternative of conventional DNA-DNA hybridization methods and it is superior to the phylogenetics methods based on sequence similarities of single genes. Detailed analysis is being performed for the re-classification of the strains examined.

Phylogenetic Analysis of Shewanella Strains by DNA Relatedness Derived from Whole Genome Microarray DNA-DNA Hybridization and Comparison with Other Methods

Energy Technology Data Exchange (ETDEWEB)

Wu, Liyou; Yi, T. Y.; Van Nostrand, Joy; Zhou, Jizhong

2010-05-17

Phylogenetic analyses were done for the Shewanella strains isolated from Baltic Sea (38 strains), US DOE Hanford Uranium bioremediation site [Hanford Reach of the Columbia River (HRCR), 11 strains], Pacific Ocean and Hawaiian sediments (8 strains), and strains from other resources (16 strains) with three out group strains, Rhodopseudomonas palustris, Clostridium cellulolyticum, and Thermoanaerobacter ethanolicus X514, using DNA relatedness derived from WCGA-based DNA-DNA hybridizations, sequence similarities of 16S rRNA gene and gyrB gene, and sequence similarities of 6 loci of Shewanella genome selected from a shared gene list of the Shewanella strains with whole genome sequenced based on the average nucleotide identity of them (ANI). The phylogenetic trees based on 16S rRNA and gyrB gene sequences, and DNA relatedness derived from WCGA hybridizations of the tested Shewanella strains share exactly the same sub-clusters with very few exceptions, in which the strains were basically grouped by species. However, the phylogenetic analysis based on DNA relatedness derived from WCGA hybridizations dramatically increased the differentiation resolution at species and strains level within Shewanella genus. When the tree based on DNA relatedness derived from WCGA hybridizations was compared to the tree based on the combined sequences of the selected functional genes (6 loci), we found that the resolutions of both methods are similar, but the clustering of the tree based on DNA relatedness derived from WMGA hybridizations was clearer. These results indicate that WCGA-based DNA-DNA hybridization is an idea alternative of conventional DNA-DNA hybridization methods and it is superior to the phylogenetics methods based on sequence similarities of single genes. Detailed analysis is being performed for the re-classification of the strains examined.

Longitudinal associations of autonomy, relatedness, and competence with the well-being of nursing home residents

NARCIS (Netherlands)

Trompetter, H.R.; Bohlmeijer, E.T.; Westerhof, G.J.; Kloos, N.

2018-01-01

Background and Objective. As proposed by the self-determination theory, satisfying nursing home residents’ needs for autonomy, relatedness, and competence may improve their well-being. This is the first study to test the longitudinal relations of the satisfaction of these three basic psychological

The Family-Relatedness of Work Decisions: A Framework and Agenda for Theory and Research

Science.gov (United States)

Greenhaus, Jeffrey H.; Powell, Gary N.

2012-01-01

Due to global trends such as the increased labor force participation of women, the growing presence of dual-earner couples and single parents in the labor force, and changing values regarding the importance of life balance, individuals' work decisions are being increasingly influenced by family considerations. However, the "family-relatedness" of…

Spallation symbiont and thorium breeding

International Nuclear Information System (INIS)

Furukawa, Kazuo

1991-01-01

The medium term world energy and environment countermeasures for 2020-2070 are not yet clearly established. The forecast of energy situation hereafter, its problems and the measures for solution are considered. World trend is removing borders, and the north-south problems are increasing the importance. The rational and clear idea with the support of concrete technology is required. The demand of energy will increase enormously at the annual rate of 2.3%. The world energy situation was forecast considering the increase of population, and it will be 115 TW at the end of the next century. The present status, problems and the countermeasures in nuclear fission energy technology are explained. The countermeasures should be based on three principles, namely Th-U-233 cycle, the utilization of molten fluoride fuel medium and the separation of molten salt breeders and molten salt reactors. Accelerator molten salt breeders, small molten salt reactors, the nuclear fuel cycle and the annihilation process for radioactive wastes are reported. The perspective that the nuclear energy system, in which the reactor safety, the measures to wastes and others are improved by the spallation-fission symbiont using thorium molten salt as the working medium, can be constructed is shown. (K.I.)

THE ROLE OF BACTERIAL SYMBIONTS IN AMINO ACID COMPOSITION OF BLACK BEAN APHIDS

Institute of Scientific and Technical Information of China (English)

MingGan; De-ChengDing; Xue-xiaMiao

2003-01-01

To evaluate the role of bacterial symbionts ( Buchnera spp. ) in the black bean aphids ( Aphis craccivora Koch), the aphids were treated with the antibiotic, rifampicin, to eliminate their intracellular symbiotic bacteria. Analysis of protein and amino acid concentration in 7-day-old of aposymbiotic aphids showed that the total protein content per mg fresh weight was significantly reduced by 29 %, but free amino acid titers were increased by 17% . The ratio of the essential amino acids was in general only around 20% essential amino acids in phloem sap of broad bean, whereas it was 44% and 37% in symbiotic and aposymbiotic aphids, respectively,suggesting that the composition of the free amino acids was unbalanced. For example, the essential amino acid,threonine represented 21. 6% of essential amino acids in symbiotic aphids, but it was only 16.7% in aposymbiotic aphids. Likewise, two nonessential amino acids, tyrosine and serine, represented 8.9% and 5.6% of total amino acids in symbiontic aphids, respectively, but they enhanced to 21.1% and 13.6% in aposymbiotic aphids. It seems likely that the elevated free amino acid concentration in aposymbiotic aphids was caused by the limited protein anabolism as the result of the unbalanced amino acid composition.

Conditional Reduction of Predation Risk Associated with a Facultative Symbiont in an Insect.

Directory of Open Access Journals (Sweden)

Sarah Polin

Full Text Available Symbionts are widespread among eukaryotes and their impacts on the ecology and evolution of their hosts are meaningful. Most insects harbour obligate and facultative symbiotic bacteria that can influence their phenotype. In the pea aphid Acyrthosiphon pisum, an astounding symbiotic-mediated phenotype has been recently observed: when infected with the symbiotic bacteria Rickettsiella viridis, young red aphid larvae become greener at adulthood and even darker green when co-infected with Rickettsiella viridis and Hamiltonella defensa. As body colour affects the susceptibility towards natural enemies in aphids, the influence of the colour change due to these facultative symbionts on the host survival in presence of predators was tested. Our results suggested that the Rickettsiella viridis infection may impact positively host survival by reducing predation risk. Due to results from uninfected aphids (i.e., more green ones attacked, the main assumption is that this symbiotic infection would deter the predatory ladybird feeding by reducing the profitability of their hosts rather than decreasing host detection through body colour change. Aphids co-infected with Rickettsiella viridis and Hamiltonella defensa were, however, more exposed to predation suggesting an ecological cost associated with multiple infections. The underlying mechanisms and ecological consequences of these symbiotic effects are discussed.

Inclusive Fitness Affects Both Prosocial and Antisocial Behavior: Target Gender and Insult Domain Moderate the Link between Genetic Relatedness and Aggression

Directory of Open Access Journals (Sweden)

Amanda N. Gesselman

2012-10-01

Full Text Available Although prior research has examined the relationship between genetic relatedness and helping behavior (Burnstein, Crandall, and Kitayama, 1994, less is known about its role in aggressive responses to insults (Fitzgerald and Ketterer, 2011. Drawing on inclusive fitness theory (Hamilton, 1964 and the Kinship, Acceptance, and Rejection Model of Altruism and Aggression (KARMAA; Webster, 2008; Webster et al., 2012, we designed a 2 (participant gender × 2 (target gender × 2 (insult: status vs. reproductive × 3 (relatedness: stranger vs. cousin vs. sibling between-person experiment in which 489 participants (a read vignettes in which a stranger, cousin, or sibling was insulted and (b reported their emotional reaction and retaliation likelihood (six-item α= .91 in response to the insult. Consistent with theory and prior research, men were significantly more aggressive than women, and people were significantly more aggressive responding to insults against kin than non-kin. These findings support theoretically-derived, dynamic, and domain-specific links among insults, gender, relatedness, and aggression.

Genomic Relatedness of Chlamydia Isolates Determined by Amplified Fragment Length Polymorphism Analysis

OpenAIRE

Meijer, Adam; Morré, Servaas A.; Van Den Brule, Adriaan J. C.; Savelkoul, Paul H. M.; Ossewaarde, Jacobus M.

1999-01-01

The genomic relatedness of 19 Chlamydia pneumoniae isolates (17 from respiratory origin and 2 from atherosclerotic origin), 21 Chlamydia trachomatis isolates (all serovars from the human biovar, an isolate from the mouse biovar, and a porcine isolate), 6 Chlamydia psittaci isolates (5 avian isolates and 1 feline isolate), and 1 Chlamydia pecorum isolate was studied by analyzing genomic amplified fragment length polymorphism (AFLP) fingerprints. The AFLP procedure was adapted from a previously...

The role of attention and relatedness in emotionally enhanced memory.

Science.gov (United States)

Talmi, Deborah; Schimmack, Ulrich; Paterson, Theone; Moscovitch, Morris

2007-02-01

Examining the positive and negative pictures separately revealed that emotionally enhanced memory (EEM) for positive pictures was mediated by attention, with no significant influence of emotional arousal, whereas the reverse was true of negative pictures. Consistent with this finding, in Experiment 2 EEM for negative pictures was found even when task emphasis was manipulated so that equivalent attention was allocated to negative and neutral pictures. The results show that attention and semantic relatedness contribute to EEM, with the extent varying with emotional valence. Negative emotion can influence memory independently of these 2 factors. (c) 2007 APA, all rights reserved.

Bacterial symbiont sharing in Megalomyrmex social parasites and their fungus-growing ant hosts

DEFF Research Database (Denmark)

Liberti, Joanito; Sapountzis, Panagiotis; Hansen, Lars H.

2015-01-01

nests such as consumption of the same fungus garden food, eating of host brood by social parasites, trophallaxis and grooming interactions between the ants, or parallel acquisition from the same nest environment. Our results imply that cohabiting ant social parasites and hosts may obtain functional...... benefits from bacterial symbiont transfer even when they are not closely related....

Memory for emotional words: The role of semantic relatedness, encoding task and affective valence.

Science.gov (United States)

Ferré, Pilar; Fraga, Isabel; Comesaña, Montserrat; Sánchez-Casas, Rosa

2015-01-01

Emotional stimuli have been repeatedly demonstrated to be better remembered than neutral ones. The aim of the present study was to test whether this advantage in memory is mainly produced by the affective content of the stimuli or it can be rather accounted for by factors such as semantic relatedness or type of encoding task. The valence of the stimuli (positive, negative and neutral words that could be either semantically related or unrelated) as well as the type of encoding task (focused on either familiarity or emotionality) was manipulated. The results revealed an advantage in memory for emotional words (either positive or negative) regardless of semantic relatedness. Importantly, this advantage was modulated by the encoding task, as it was reliable only in the task which focused on emotionality. These findings suggest that congruity with the dimension attended at encoding might contribute to the superiority in memory for emotional words, thus offering us a more complex picture of the underlying mechanisms behind the advantage for emotional information in memory.

Interpersonal relatedness and self-definition in normal and disrupted personality development: retrospect and prospect.

Science.gov (United States)

Luyten, Patrick; Blatt, Sidney J

2013-04-01

Two-polarities models of personality propose that personality development evolves through a dialectic synergistic interaction between two fundamental developmental psychological processes across the life span-the development of interpersonal relatedness on the one hand and of self-definition on the other. This article offers a broad review of extant research concerning these models, discusses their implications for psychology and psychiatry, and addresses future research perspectives deriving from these models. We first consider the implications of findings in this area for clinical research and practice. This is followed by a discussion of emerging research findings concerning the role of developmental, cross-cultural, evolutionary, and neurobiological factors influencing the development of these two fundamental personality dimensions. Taken together, this body of research suggests that theoretical formulations that focus on interpersonal relatedness and self-definition as central coordinates in personality development and psychopathology provide a comprehensive conceptual paradigm for future research in psychology and psychiatry exploring the interactions among neurobiological, psychological, and sociocultural factors in adaptive and disrupted personality development across the life span.

Microsatellite marker-based genetic analysis of relatedness between commercial and heritage turkeys (Meleagris gallopavo).

Science.gov (United States)

Kamara, D; Gyenai, K B; Geng, T; Hammade, H; Smith, E J

2007-01-01

The turkey is second only to the chicken in importance as an agriculturally important poultry species. Unlike the chicken, however, genetic studies of the turkey continue to be limited. For example, to date, many genomic investigations have been conducted to characterize genetic relationships between commercial (CO) and non-CO chicken breeds, whereas the nature of the genetic relatedness between CO and heritage turkeys remains unknown. The objective of the current research was to use microsatellites to analyze the genetic relatedness between CO and heritage domestic turkeys including Narragansett, Bourbon Red, Blue Slate, Spanish Black, and Royal Palm. Primer pairs specific for 10 previously described turkey microsatellite markers were used. The phylogenetic analysis showed that the Blue Slate, Bourbon Red, and Narragansett were genetically closely related to the CO strain, with a Nei distance of 0.30, and the Royal Palm and Spanish Black were the least related to the CO strain, with Nei distances of 0.41 and 0.40, respectively. The present work provides a foundation for the basis of using heritage turkeys to genetically improve CO populations by introgression.

Effects of semantic relatedness on age-related associative memory deficits: the role of theta oscillations.

Science.gov (United States)

Crespo-Garcia, Maite; Cantero, Jose L; Atienza, Mercedes

2012-07-16

Growing evidence suggests that age-related deficits in associative memory are alleviated when the to-be-associated items are semantically related. Here we investigate whether this beneficial effect of semantic relatedness is paralleled by spatio-temporal changes in cortical EEG dynamics during incidental encoding. Young and older adults were presented with faces at a particular spatial location preceded by a biographical cue that was either semantically related or unrelated. As expected, automatic encoding of face-location associations benefited from semantic relatedness in the two groups of age. This effect correlated with increased power of theta oscillations over medial and anterior lateral regions of the prefrontal cortex (PFC) and lateral regions of the posterior parietal cortex (PPC) in both groups. But better-performing elders also showed increased brain-behavior correlation in the theta band over the right inferior frontal gyrus (IFG) as compared to young adults. Semantic relatedness was, however, insufficient to fully eliminate age-related differences in associative memory. In line with this finding, poorer-performing elders relative to young adults showed significant reductions of theta power in the left IFG that were further predictive of behavioral impairment in the recognition task. All together, these results suggest that older adults benefit less than young adults from executive processes during encoding mainly due to neural inefficiency over regions of the left ventrolateral prefrontal cortex (VLPFC). But this associative deficit may be partially compensated for by engaging preexistent semantic knowledge, which likely leads to an efficient recruitment of attentional and integration processes supported by the left PPC and left anterior PFC respectively, together with neural compensatory mechanisms governed by the right VLPFC. Copyright © 2012 Elsevier Inc. All rights reserved.

Who Makes the Choice? Rethinking the Role of Autonomy and Relatedness in Chinese Children's Motivation

Science.gov (United States)

Bao, Xue-Hua; Lam, Shui-Fong

2008-01-01

The importance of autonomy for children's motivation in collectivistic cultures has been debated hotly. With the understanding that autonomy is not equivalent to freedom of choice, 4 studies addressed this debate by investigating how socioemotional relatedness, choice, and autonomy were related to Chinese children's motivation. Study 1 (N = 56,…

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

Science.gov (United States)

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

2016-03-29

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

Is the higher rate of parental child homicide in stepfamilies an effect of non-genetic relatedness?

Institute of Scientific and Technical Information of China (English)

Hans TEMRIN; Johanna NORDLUND; Mikael RYING; Birgitta S. TULLBERG

2011-01-01

In an evolutionary perspective individuals are expected to vary the degree of parental love and care in relation to the fitness value that a child represents. Hence, stepparents are expected to show less solicitude than genetically related parents, and this lack of genetic relatedness has been used to explain the higher frequencies of child abuse and homicide found in stepfamilies.However, other factors than non-genetic relatedness may cause this over-representation in stepfamilies. Here we use a 45-year data set of parental child homicides in Sweden to test two hypotheses related to the higher incidence in stepfamilies: 1) adults in different types of family differ in their general disposition to use violence, and 2) parents are more likely to kill stepchildren than genetically related children. Of the 152 perpetrators in biparental families there was an overrepresentation of perpetrators in stepfamilies (n=27) compared with the general population. We found support for the first hypothesis in that both general and violent crime rates were higher in stepfamilies, both in the general population and among perpetrators of child homicide. However, we found no support for the second hypothesis because of the 27 perpetrators in stepfamilies the perpetrator killed a genetically related child in 13 cases, a stepchild in 13 cases and both types of children in one case. Moreover, out of the 12 families where the perpetrator lived with both stepchildren and genetic children, there was no bias towards killing stepchildren. Thus, we found no evidence for an effect of non-genetic relatedness per se [Current Zoology 57 (3): 253-59, 2011].

Pederin-type pathways of uncultivated bacterial symbionts: analysis of o-methyltransferases and generation of a biosynthetic hybrid.

Science.gov (United States)

Zimmermann, Katrin; Engeser, Marianne; Blunt, John W; Munro, Murray H G; Piel, Jörn

2009-03-04

The complex polyketide pederin is a potent antitumor agent isolated from Paederus spp. rove beetles. We have previously isolated a set of genes from a bacterial endosymbiont that are good candidates for pederin biosynthesis. To biochemically study this pathway, we expressed three methyltransferases from the putative pederin pathway and used the partially unmethylated analogue mycalamide A from the marine sponge Mycale hentscheli as test substrate. Analysis by high-resolution MS/MS and NMR revealed that PedO regiospecifically methylates the marine compound to generate the nonnatural hybrid compound 18-O-methylmycalamide A with increased cytotoxicity. To our knowledge, this is the first biochemical evidence that invertebrates can obtain defensive complex polyketides from bacterial symbionts.

Predictors of Grandparental Investment Decisions in Contemporary Europe: Biological Relatedness and Beyond

Science.gov (United States)

Coall, David A.; Hilbrand, Sonja; Hertwig, Ralph

2014-01-01

Across human cultures, grandparents make a valued contribution to the health of their families and communities. Moreover, evidence is gathering that grandparents have a positive impact on the development of grandchildren in contemporary industrialized societies. A broad range of factors that influence the likelihood grandparents will invest in their grandchildren has been explored by disciplines as diverse as sociology, economics, psychology and evolutionary biology. To progress toward an encompassing framework, this study will include biological relatedness between grandparents and grandchildren, a factor central to some discipline's theoretical frameworks (e.g., evolutionary biology), next to a wide range of other factors in an analysis of grandparental investment in contemporary Europe. This study draws on data collected in the Survey of Health, Ageing and Retirement in Europe from 11 European countries that included 22,967 grandparent–child dyads. Grandparents reported biological relatedness, and grandparental investment was measured as the frequency of informal childcare. Biological and non-biological grandparents differed significantly in a variety of individual, familial and area-level characteristics. Furthermore, many other economic, sociological, and psychological factors also influenced grandparental investment. When they were controlled, biological grandparents, relative to non-biological grandparents, were more likely to invest heavily, looking after their grandchildren almost daily or weekly. Paradoxically, however, they were also more likely to invest nothing at all. We discuss the methodological and theoretical implications of these findings across disciplines. PMID:24416193

Predictors of grandparental investment decisions in contemporary Europe: biological relatedness and beyond.

Science.gov (United States)

Coall, David A; Hilbrand, Sonja; Hertwig, Ralph

2014-01-01

Across human cultures, grandparents make a valued contribution to the health of their families and communities. Moreover, evidence is gathering that grandparents have a positive impact on the development of grandchildren in contemporary industrialized societies. A broad range of factors that influence the likelihood grandparents will invest in their grandchildren has been explored by disciplines as diverse as sociology, economics, psychology and evolutionary biology. To progress toward an encompassing framework, this study will include biological relatedness between grandparents and grandchildren, a factor central to some discipline's theoretical frameworks (e.g., evolutionary biology), next to a wide range of other factors in an analysis of grandparental investment in contemporary Europe. This study draws on data collected in the Survey of Health, Ageing and Retirement in Europe from 11 European countries that included 22,967 grandparent-child dyads. Grandparents reported biological relatedness, and grandparental investment was measured as the frequency of informal childcare. Biological and non-biological grandparents differed significantly in a variety of individual, familial and area-level characteristics. Furthermore, many other economic, sociological, and psychological factors also influenced grandparental investment. When they were controlled, biological grandparents, relative to non-biological grandparents, were more likely to invest heavily, looking after their grandchildren almost daily or weekly. Paradoxically, however, they were also more likely to invest nothing at all. We discuss the methodological and theoretical implications of these findings across disciplines.

Can Relatedness be a Key to Employee Motivation? : A quantitative study of the linkage between the three basic needs and internalization in the workplace.

OpenAIRE

Halvarsson, Jon; Engman, Emma

2014-01-01

Workplace motivation is important for organizations in all contexts. Motivation can be both extrinsic and intrinsic, simplified meaning it derives from expectations of external rewards or comes from enjoyment of the task itself. Whether the motivation becomes extrinsic or intrinsic depends primarily on satisfaction of the basic needs, namely autonomy, competence and relatedness. With stance in the self-determination theory this thesis explored the concept of relatedness, alongside the two oth...

Genomic diversification of giant enteric symbionts reflects host dietary lifestyles

KAUST Repository

Ngugi, David

2017-08-24

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

The ties that bind: genetic relatedness predicts the fission and fusion of social groups in wild African elephants.

Science.gov (United States)

Archie, Elizabeth A; Moss, Cynthia J; Alberts, Susan C

2006-03-07

Many social animals live in stable groups. In contrast, African savannah elephants (Loxodonta africana) live in unusually fluid, fission-fusion societies. That is, 'core' social groups are composed of predictable sets of individuals; however, over the course of hours or days, these groups may temporarily divide and reunite, or they may fuse with other social groups to form much larger social units. Here, we test the hypothesis that genetic relatedness predicts patterns of group fission and fusion among wild, female African elephants. Our study of a single Kenyan population spans 236 individuals in 45 core social groups, genotyped at 11 microsatellite and one mitochondrial DNA (mtDNA) locus. We found that genetic relatedness predicted group fission; adult females remained with their first order maternal relatives when core groups fissioned temporarily. Relatedness also predicted temporary fusion between social groups; core groups were more likely to fuse with each other when the oldest females in each group were genetic relatives. Groups that shared mtDNA haplotypes were also significantly more likely to fuse than groups that did not share mtDNA. Our results suggest that associations between core social groups persist for decades after the original maternal kin have died. We discuss these results in the context of kin selection and its possible role in the evolution of elephant sociality.

A new niche for Vibrio logei, the predominant light organ symbiont of squids in the genus Sepiola.

Science.gov (United States)

Fidopiastis, P M; von Boletzky, S; Ruby, E G

1998-01-01

Two genera of sepiolid squids--Euprymna, found primarily in shallow, coastal waters of Hawaii and the Western Pacific, and Sepiola, the deeper-, colder-water-dwelling Mediterranean and Atlantic squids--are known to recruit luminous bacteria into light organ symbioses. The light organ symbiont of Euprymna spp. is Vibrio fischeri, but until now, the light organ symbionts of Sepiola spp. have remained inadequately identified. We used a combination of molecular and physiological characteristics to reveal that the light organs of Sepiola affinis and Sepiola robusta contain a mixed population of Vibrio logei and V. fischeri, with V. logei comprising between 63 and 100% of the bacteria in the light organs that we analyzed. V. logei had not previously been known to exist in such symbioses. In addition, this is the first report of two different species of luminous bacteria co-occurring within a single light organ. The luminescence of these symbiotic V. logei strains, as well as that of other isolates of V. logei tested, is reduced when they are grown at temperatures above 20 degrees C, partly due to a limitation in the synthesis of aliphatic aldehyde, a substrate of the luminescence reaction. In contrast, the luminescence of the V. fischeri symbionts is optimal above 24 degrees C and is not enhanced by aldehyde addition. Also, V. fischeri strains were markedly more successful than V. logei at colonizing the light organs of juvenile Euprymna scolopes, especially at 26 degrees C. These findings have important implications for our understanding of the ecological dynamics and evolution of cooperative, and perhaps pathogenic, associations of Vibrio spp. with their animal hosts.

Dead or Alive? Knowledge about a Sibling's Death Varies by Genetic Relatedness in a Modern Society

NARCIS (Netherlands)

Pollet, Thomas V.; Nettle, Daniel

2009-01-01

Using a large sample of non-institutionalized individuals from the Netherlands (n = 7610), we examined the influence of relatedness on an individual's knowledge about whether their sibling is alive or not. Respondents were generally less likely to know whether their sibling was alive if they were

Cohorts and Relatedness: Self-Determination Theory as an Explanation of How Learning Communities Affect Educational Outcomes

Science.gov (United States)

Beachboard, Martine Robinson; Beachboard, John C.; Li, Wenling; Adkison, Stephen R.

2011-01-01

This study examines whether feelings of relatedness constitute a substantial means by which learning communities (cohorts) improve learning outcomes in higher education. It applies Ryan and Deci's Self-Determination Theory to an analysis of the National Survey of Student Engagement. The SDT hypothesizes that environments that support perceptions…

Human Kin Investment as a Function of Genetic Relatedness and Lineage

Directory of Open Access Journals (Sweden)

Gregory D. Webster

2004-01-01

Full Text Available Two independent samples of students were asked to allocate fictional lotteries of varying dollar amounts to their blood relatives. In both studies, a reliable genetic relatedness by lineage interaction emerged, such that the genetic effect was a more positive predictor of percent of money allocated for relatives of a direct lineage (e.g., parents, grandparents than it was for peripheral relatives (e.g., siblings, aunts and uncles. In a third study, this interaction was replicated in an archival analysis of wills. The implications of accounting for differences in relatives' lineages in studies of kin investment are discussed.

Is the higher rate of parental child homicide in stepfamilies an effect of non-genetic relatedness?

Directory of Open Access Journals (Sweden)

Hans TEMRIN, Johanna NORDLUND, Mikael RYING, Birgitta S. TULLBERG

2011-06-01

Full Text Available In an evolutionary perspective individuals are expected to vary the degree of parental love and care in relation to the fitness value that a child represents. Hence, stepparents are expected to show less solicitude than genetically related parents, and this lack of genetic relatedness has been used to explain the higher frequencies of child abuse and homicide found in stepfamilies. However, other factors than non-genetic relatedness may cause this over-representation in stepfamilies. Here we use a 45-year data set of parental child homicides in Sweden to test two hypotheses related to the higher incidence in stepfamilies: 1 adults in different types of family differ in their general disposition to use violence, and 2 parents are more likely to kill stepchildren than genetically related children. Of the 152 perpetrators in biparental families there was an overrepresentation of perpetrators in stepfamilies (n=27 compared with the general population. We found support for the first hypothesis in that both general and violent crime rates were higher in stepfamilies, both in the general population and among perpetrators of child homicide. However, we found no support for the second hypothesis because of the 27 perpetrators in stepfamilies the perpetrator killed a genetically related child in 13 cases, a stepchild in 13 cases and both types of children in one case. Moreover, out of the 12 families where the perpetrator lived with both stepchildren and genetic children, there was no bias towards killing stepchildren. Thus, we found no evidence for an effect of non-genetic relatedness per se [Current Zoology 57 (3: 253–259, 2011].

Immunochemical localization of ribulose-1,5-bisphosphate carboxylase in the symbiont-containing gills of Solemya velum (Bivalvia : Mollusca)

NARCIS (Netherlands)

Cavanaugh, Colleen M.; Abbott, Marilyn S.; Veenhuis, Marten

1988-01-01

The distribution of the Calvin cycle enzyme ribulose-1,5-bisphosphate carboxylase (RbuP2Case; EC 4.1.1.39) was examined by using two immunological methods in tissues of Solemya velum, an Atlantic coast bivalve containing putative chemoautotrophic symbionts. Antibodies elicited by the purified large

The Role of Maternal Support of Competence, Autonomy and Relatedness in Children's Interests and Mastery Orientation

Science.gov (United States)

Aunola, Kaisa; Viljaranta, Jaana; Lehtinen, Erno; Nurmi, Jari-Erik

2013-01-01

The present study investigated the extent to which mothers' support for their children's sense of competence, autonomy and relatedness predicts their children's interest in math and reading, and also their mastery orientation, during the transition to primary school. One hundred fifty-two children were examined twice during their first grade year…

How Well Do Molecular and Pedigree Relatedness Correspond, in Populations with Diverse Mating Systems, and Various Types and Quantities of Molecular and Demographic Data?

Science.gov (United States)

Kopps, Anna M; Kang, Jungkoo; Sherwin, William B; Palsbøll, Per J

2015-06-30

Kinship analyses are important pillars of ecological and conservation genetic studies with potentially far-reaching implications. There is a need for power analyses that address a range of possible relationships. Nevertheless, such analyses are rarely applied, and studies that use genetic-data-based-kinship inference often ignore the influence of intrinsic population characteristics. We investigated 11 questions regarding the correct classification rate of dyads to relatedness categories (relatedness category assignments; RCA) using an individual-based model with realistic life history parameters. We investigated the effects of the number of genetic markers; marker type (microsatellite, single nucleotide polymorphism SNP, or both); minor allele frequency; typing error; mating system; and the number of overlapping generations under different demographic conditions. We found that (i) an increasing number of genetic markers increased the correct classification rate of the RCA so that up to >80% first cousins can be correctly assigned; (ii) the minimum number of genetic markers required for assignments with 80 and 95% correct classifications differed between relatedness categories, mating systems, and the number of overlapping generations; (iii) the correct classification rate was improved by adding additional relatedness categories and age and mitochondrial DNA data; and (iv) a combination of microsatellite and single-nucleotide polymorphism data increased the correct classification rate if power analyses are essential for empirical studies. Copyright © 2015 Kopps et al.

How Teacher Emotional Support Motivates Students: The Mediating Roles of Perceived Peer Relatedness, Autonomy Support, and Competence

Science.gov (United States)

Ruzek, Erik A.; Hafen, Christopher A.; Allen, Joseph P.; Gregory, Anne; Mikami, Amori Yee; Pianta, Robert C.

2016-01-01

Multilevel mediation analyses test whether students' mid-year reports of classroom experiences of autonomy, relatedness with peers, and competence mediate associations between early in the school year emotionally-supportive teacher-student interactions (independently observed) and student-reported academic year changes in mastery motivation and…

Effects of Forward and Backward Contextual Elaboration on Lexical Inferences: Evidence from a Semantic Relatedness Judgment Task

Science.gov (United States)

Hamada, Akira

2015-01-01

Three experiments examined whether the process of lexical inferences differs according to the direction of contextual elaboration using a semantic relatedness judgment task. In Experiment 1, Japanese university students read English sentences where target unknown words were semantically elaborated by prior contextual information (forward lexical…

Genetic variation, relatedness, and effective population size of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska

Science.gov (United States)

Cronin, Matthew A.; Amstrup, Steven C.; Talbot, Sandra L.; Sage, George K.; Amstrup, Kristin S.

2009-01-01

Polar bears (Ursus maritimus) are unique among bears in that they are adapted to the Arctic sea ice environment. Genetic data are useful for understanding their evolution and can contribute to management. We assessed parentage and relatedness of polar bears in the southern Beaufort Sea, Alaska, with genetic data and field observations of age, sex, and mother–offspring and sibling relationships. Genotypes at 14 microsatellite DNA loci for 226 bears indicate that genetic variation is comparable to other populations of polar bears with mean number of alleles per locus of 7.9 and observed and expected heterozygosity of 0.71. The genetic data verified 60 field-identified mother–offspring pairs and identified 10 additional mother–cub pairs and 48 father–offspring pairs. The entire sample of related and unrelated bears had a mean pairwise relatedness index (rxy) of approximately zero, parent–offspring and siblings had rxy of approximately 0.5, and 5.2% of the samples had rxy values within the range expected for parent-offspring. Effective population size (Ne= 277) and the ratio of Ne to total population size (Ne/N = 0.182) were estimated from the numbers of reproducing males and females. Ne estimates with genetic methods gave variable results. Our results verify and expand field data on reproduction by females and provide new data on reproduction by males and estimates of relatedness and Ne in a polar bear population.

Genetic variation, relatedness, and effective population size of polar bears (Ursus maritimus) in the southern Beaufort Sea, Alaska.

Science.gov (United States)

Cronin, Matthew A; Amstrup, Steven C; Talbot, Sandra L; Sage, George K; Amstrup, Kristin S

2009-01-01

Polar bears (Ursus maritimus) are unique among bears in that they are adapted to the Arctic sea ice environment. Genetic data are useful for understanding their evolution and can contribute to management. We assessed parentage and relatedness of polar bears in the southern Beaufort Sea, Alaska, with genetic data and field observations of age, sex, and mother-offspring and sibling relationships. Genotypes at 14 microsatellite DNA loci for 226 bears indicate that genetic variation is comparable to other populations of polar bears with mean number of alleles per locus of 7.9 and observed and expected heterozygosity of 0.71. The genetic data verified 60 field-identified mother-offspring pairs and identified 10 additional mother-cub pairs and 48 father-offspring pairs. The entire sample of related and unrelated bears had a mean pairwise relatedness index (r(xy)) of approximately zero, parent-offspring and siblings had r(xy) of approximately 0.5, and 5.2% of the samples had r(xy) values within the range expected for parent-offspring. Effective population size (N(e) = 277) and the ratio of N(e) to total population size (N(e)/N = 0.182) were estimated from the numbers of reproducing males and females. N(e) estimates with genetic methods gave variable results. Our results verify and expand field data on reproduction by females and provide new data on reproduction by males and estimates of relatedness and N(e) in a polar bear population.

An Accurate Method for Inferring Relatedness in Large Datasets of Unphased Genotypes via an Embedded Likelihood-Ratio Test

KAUST Repository

Rodriguez, Jesse M.; Batzoglou, Serafim; Bercovici, Sivan

2013-01-01

, accurate and efficient detection of hidden relatedness becomes a challenge. To enable disease-mapping studies of increasingly large cohorts, a fast and accurate method to detect IBD segments is required. We present PARENTE, a novel method for detecting

Is Speed of Integration really a Success Factor of Mergers and Acquisitions? : An Analysis of the Role of Internal and External Relatedness

OpenAIRE

Homburg, Christian; Bucerius, Matthias

2006-01-01

Previous research on mergers and acquisitions (M&A) has neglected the issue of speed of post merger integration (PMI) by and large. This paper argues that there are benefits and detriments associated with speed of integration. Thus, in some situations speed may be highly beneficial whereas in others it may be harmful to the success of a merger or acquisition. It is argued that the benefits and detriments of speed of integration depend on the magnitude of internal and external relatedness ...

Evidence of diversity and recombination in Arsenophonus symbionts of the Bemisia tabaci species complex

Directory of Open Access Journals (Sweden)

Mouton Laurence

2012-01-01

Full Text Available Abstract Background Maternally inherited bacterial symbionts infecting arthropods have major implications on host ecology and evolution. Among them, the genus Arsenophonus is particularly characterized by a large host spectrum and a wide range of symbiotic relationships (from mutualism to parasitism, making it a good model to study the evolution of host-symbiont associations. However, few data are available on the diversity and distribution of Arsenophonus within host lineages. Here, we propose a survey on Arsenophonus diversity in whitefly species (Hemiptera, in particular the Bemisia tabaci species complex. This polyphagous insect pest is composed of genetic groups that differ in many ecological aspects. They harbor specific bacterial communities, among them several lineages of Arsenophonus, enabling a study of the evolutionary history of these bacteria at a fine host taxonomic level, in association to host geographical range and ecology. Results Among 152 individuals, our analysis identified 19 allelic profiles and 6 phylogenetic groups, demonstrating this bacterium's high diversity. These groups, based on Arsenophonus phylogeny, correlated with B. tabaci genetic groups with two exceptions reflecting horizontal transfers. None of three genes analyzed provided evidence of intragenic recombination, but intergenic recombination events were detected. A mutation inducing a STOP codon on one gene in a strain infecting one B. tabaci genetic group was also found. Phylogenetic analyses of the three concatenated loci revealed the existence of two clades of Arsenophonus. One, composed of strains found in other Hemiptera, could be the ancestral clade in whiteflies. The other, which regroups strains found in Hymenoptera and Diptera, may have been acquired more recently by whiteflies through lateral transfers. Conclusions This analysis of the genus Arsenophonus revealed a diversity within the B. tabaci species complex which resembles that reported on the

Experimental evidence that kin discrimination in the Seychelles warbler is based on association and not on genetic relatedness

NARCIS (Netherlands)

Komdeur, J; Richardson, DS; Burke, T; Richardson, David S.

2004-01-01

In cooperative breeding systems driven by kin selection, effective kin-recognition cues are important. Recognition could be achieved by the direct assessment of the genetic relatedness of individuals or by learning through association. In the Seychelles warbler, Acrocephalus sechellensis, female

Distinct effects of the nephridial symbionts Verminephrobacter and Candidatus Nephrothrix on reproduction and maturation of its earthworm host Eisenia andrei

DEFF Research Database (Denmark)

Viana, Flavia; Paz, Laura-Carlota; Methling, Karen

2018-01-01

to these two symbionts also hosts Agromyces-like bacteria in its mixed nephridial community: while growth was identical between control, Verminephrobacter-free and aposymbiotic worms, control worms produced significantly more cocoons and offspring than both Verminephrobacter-free and aposymbiotic worms...

Robust Inference of Population Structure for Ancestry Prediction and Correction of Stratification in the Presence of Relatedness

Science.gov (United States)

Conomos, Matthew P.; Miller, Mike; Thornton, Timothy

2016-01-01

Population structure inference with genetic data has been motivated by a variety of applications in population genetics and genetic association studies. Several approaches have been proposed for the identification of genetic ancestry differences in samples where study participants are assumed to be unrelated, including principal components analysis (PCA), multi-dimensional scaling (MDS), and model-based methods for proportional ancestry estimation. Many genetic studies, however, include individuals with some degree of relatedness, and existing methods for inferring genetic ancestry fail in related samples. We present a method, PC-AiR, for robust population structure inference in the presence of known or cryptic relatedness. PC-AiR utilizes genome-screen data and an efficient algorithm to identify a diverse subset of unrelated individuals that is representative of all ancestries in the sample. The PC-AiR method directly performs PCA on the identified ancestry representative subset and then predicts components of variation for all remaining individuals based on genetic similarities. In simulation studies and in applications to real data from Phase III of the HapMap Project, we demonstrate that PC-AiR provides a substantial improvement over existing approaches for population structure inference in related samples. We also demonstrate significant efficiency gains, where a single axis of variation from PC-AiR provides better prediction of ancestry in a variety of structure settings than using ten (or more) components of variation from widely used PCA and MDS approaches. Finally, we illustrate that PC-AiR can provide improved population stratification correction over existing methods in genetic association studies with population structure and relatedness. PMID:25810074

Chemical fingerprints encode mother–offspring similarity, colony membership, relatedness, and genetic quality in fur seals

Science.gov (United States)

Stoffel, Martin A.; Caspers, Barbara A.; Forcada, Jaume; Giannakara, Athina; Baier, Markus; Eberhart-Phillips, Luke; Müller, Caroline; Hoffman, Joseph I.

2015-01-01

Chemical communication underpins virtually all aspects of vertebrate social life, yet remains poorly understood because of its highly complex mechanistic basis. We therefore used chemical fingerprinting of skin swabs and genetic analysis to explore the chemical cues that may underlie mother–offspring recognition in colonially breeding Antarctic fur seals. By sampling mother–offspring pairs from two different colonies, using a variety of statistical approaches and genotyping a large panel of microsatellite loci, we show that colony membership, mother–offspring similarity, heterozygosity, and genetic relatedness are all chemically encoded. Moreover, chemical similarity between mothers and offspring reflects a combination of genetic and environmental influences, the former partly encoded by substances resembling known pheromones. Our findings reveal the diversity of information contained within chemical fingerprints and have implications for understanding mother–offspring communication, kin recognition, and mate choice. PMID:26261311

Genetic and genomic diversity studies of Acacia symbionts in Senegal reveal new species of Mesorhizobium with a putative geographical pattern.

Science.gov (United States)

Diouf, Fatou; Diouf, Diegane; Klonowska, Agnieszka; Le Queré, Antoine; Bakhoum, Niokhor; Fall, Dioumacor; Neyra, Marc; Parrinello, Hugues; Diouf, Mayecor; Ndoye, Ibrahima; Moulin, Lionel

2015-01-01

Acacia senegal (L) Willd. and Acacia seyal Del. are highly nitrogen-fixing and moderately salt tolerant species. In this study we focused on the genetic and genomic diversity of Acacia mesorhizobia symbionts from diverse origins in Senegal and investigated possible correlations between the genetic diversity of the strains, their soil of origin, and their tolerance to salinity. We first performed a multi-locus sequence analysis on five markers gene fragments on a collection of 47 mesorhizobia strains of A. senegal and A. seyal from 8 localities. Most of the strains (60%) clustered with the M. plurifarium type strain ORS 1032T, while the others form four new clades (MSP1 to MSP4). We sequenced and assembled seven draft genomes: four in the M. plurifarium clade (ORS3356, ORS3365, STM8773 and ORS1032T), one in MSP1 (STM8789), MSP2 (ORS3359) and MSP3 (ORS3324). The average nucleotide identities between these genomes together with the MLSA analysis reveal three new species of Mesorhizobium. A great variability of salt tolerance was found among the strains with a lack of correlation between the genetic diversity of mesorhizobia, their salt tolerance and the soils samples characteristics. A putative geographical pattern of A. senegal symbionts between the dryland north part and the center of Senegal was found, reflecting adaptations to specific local conditions such as the water regime. However, the presence of salt does not seem to be an important structuring factor of Mesorhizobium species.

The presence of the Indo-Pacific symbiont-bearing foraminifer Amphistegina lobifera in Greek coastal ecosystems (Aegean Sea, Eastern Mediterranean

Directory of Open Access Journals (Sweden)

M.V. TRIANTAPHYLLOU

2009-12-01

Full Text Available During the last decades, hundreds of species of Indo-Pacific origin from the Red Sea have traversed the Suez Canal and settled in the Eastern Mediterranean. Nowadays, Amphistegina lobifera Larsen, is known to be a successful immigrant that is widely distributed in the coastal ecosystems of the Eastern Mediterranean Sea. Amphistegina is the most common epiphytic, symbiont- bearing large foraminifer. In this study we provide additional data on the presence of this species in the coastal ecosystems of Aegean Sea, Greece. The high relative abundance of A. lobifera is the result of very successful adaptation of this species to local conditions and suggests that it has become a significant part of the epiphytic foraminiferal fauna.

The Relationship between the Physical Activity Environment, Nature Relatedness, Anxiety, and the Psychological Well-being Benefits of Regular Exercisers

Directory of Open Access Journals (Sweden)

Emma Lawton

2017-06-01

Full Text Available Research from a variety of scientific fields suggests that physical activity in nature and feelings of connection to nature enhance psychological health and well-being. This study investigated the psychological health and well-being impact of the physical activity environment for those already undertaking the recommended weekly amount of physical activity. This topic is important for the design of health and well-being environments and interventions involving physical activity. Participants (N = 262 aged 18–71 years (M = 34.5, SD = 13.1 who met the UK physical activity guidelines completed the Nature Relatedness Scale, the trait section of the State Trait Inventory for Cognitive and Somatic Anxiety and the Psychological Well-Being Scale. Analysis via Multivariate ANOVA indicated that participants who engaged in outdoor physical activity reported significantly lower somatic anxiety levels and higher Nature Relatedness experience (NRexp. Significant results were not evident for wellbeing. Hierarchical regressions revealed that the psychological well-being facet of autonomy, NRexp, and outdoor physical activity predicted lower somatic anxiety, whereas indoor physical activity predicted higher somatic anxiety. Results indicate that somatic anxiety is lower for outdoor physical activity participation, and that outdoor activity, in conjunction with autonomy and NRexp, predicts lower anxiety levels. The findings extend previous work by demonstrating the impact of the physical activity environment on anxiety levels, as well as the contribution of outdoor physical activity and well-being facets to the previously established Nature Relatedness-anxiety relationship.

The Relationship between the Physical Activity Environment, Nature Relatedness, Anxiety, and the Psychological Well-being Benefits of Regular Exercisers

Science.gov (United States)

Lawton, Emma; Brymer, Eric; Clough, Peter; Denovan, Andrew

2017-01-01

Research from a variety of scientific fields suggests that physical activity in nature and feelings of connection to nature enhance psychological health and well-being. This study investigated the psychological health and well-being impact of the physical activity environment for those already undertaking the recommended weekly amount of physical activity. This topic is important for the design of health and well-being environments and interventions involving physical activity. Participants (N = 262) aged 18–71 years (M = 34.5, SD = 13.1) who met the UK physical activity guidelines completed the Nature Relatedness Scale, the trait section of the State Trait Inventory for Cognitive and Somatic Anxiety and the Psychological Well-Being Scale. Analysis via Multivariate ANOVA indicated that participants who engaged in outdoor physical activity reported significantly lower somatic anxiety levels and higher Nature Relatedness experience (NRexp). Significant results were not evident for wellbeing. Hierarchical regressions revealed that the psychological well-being facet of autonomy, NRexp, and outdoor physical activity predicted lower somatic anxiety, whereas indoor physical activity predicted higher somatic anxiety. Results indicate that somatic anxiety is lower for outdoor physical activity participation, and that outdoor activity, in conjunction with autonomy and NRexp, predicts lower anxiety levels. The findings extend previous work by demonstrating the impact of the physical activity environment on anxiety levels, as well as the contribution of outdoor physical activity and well-being facets to the previously established Nature Relatedness-anxiety relationship. PMID:28694788

Towards a molecular understanding of symbiont function: Identification of a fungal gene for the degradation of xylan in the fungus gardens of leaf-cutting ants

Directory of Open Access Journals (Sweden)

Lange Lene

2008-02-01

Full Text Available Abstract Background Leaf-cutting ants live in symbiosis with a fungus that they rear for food by providing it with live plant material. Until recently the fungus' main inferred function was to make otherwise inaccessible cell wall degradation products available to the ants, but new studies have shed doubt on this idea. To provide evidence for the cell wall degrading capacity of the attine ant symbiont, we designed PCR primers from conserved regions of known xylanase genes, to be used in PCR with genomic DNA from the symbiont as template. We also measured xylanase, cellulase and proteinase activities in the fungus gardens in order to investigate the dynamics of degradation activities. Results We cloned a xylanase gene from the mutualistic fungus of Acromyrmex echinatior, determined its protein sequence, and inserted it in a yeast expression vector to confirm its substrate specificity. Our results show that the fungus has a functional xylanase gene. We also show by lab experiments in vivo that the activity of fungal xylanase and cellulase is not evenly distributed, but concentrated in the lower layer of fungus gardens, with only modest activity in the middle layer where gongylidia are produced and intermediate activity in the newly established top layer. This vertical distribution appears to be negatively correlated with the concentration of glucose, which indicates a directly regulating role of glucose, as has been found in other fungi and has been previously suggested for the ant fungal symbiont. Conclusion The mutualistic fungus of Acromyrmex echinatior has a functional xylanase gene and is thus presumably able to at least partially degrade the cell walls of leaves. This finding supports a saprotrophic origin of the fungal symbiont. The observed distribution of enzyme activity leads us to propose that leaf-substrate degradation in fungus gardens is a multi-step process comparable to normal biodegradation of organic matter in soil ecosystems

Genomic Changes Associated with the Evolutionary Transitions of Nostoc to a Plant Symbiont

Science.gov (United States)

Liaimer, Anton; Pederson, Eric; Kim, Sea-Yong; Shapiro, Nicole; Woyke, Tanja; Altermark, Bjørn; Pawlowski, Katharina; Weyman, Philip D; Dupont, Christopher L

2018-01-01

Abstract Cyanobacteria belonging to the genus Nostoc comprise free-living strains and also facultative plant symbionts. Symbiotic strains can enter into symbiosis with taxonomically diverse range of host plants. Little is known about genomic changes associated with evolutionary transition of Nostoc from free-living to plant symbiont. Here, we compared the genomes derived from 11 symbiotic Nostoc strains isolated from different host plants and infer phylogenetic relationships between strains. Phylogenetic reconstructions of 89 Nostocales showed that symbiotic Nostoc strains with a broad host range, entering epiphytic and intracellular or extracellular endophytic interactions, form a monophyletic clade indicating a common evolutionary history. A polyphyletic origin was found for Nostoc strains which enter only extracellular symbioses, and inference of transfer events implied that this trait was likely acquired several times in the evolution of the Nostocales. Symbiotic Nostoc strains showed enriched functions in transport and metabolism of organic sulfur, chemotaxis and motility, as well as the uptake of phosphate, branched-chain amino acids, and ammonium. The genomes of the intracellular clade differ from that of other Nostoc strains, with a gain/enrichment of genes encoding proteins to generate l-methionine from sulfite and pathways for the degradation of the plant metabolites vanillin and vanillate, and of the macromolecule xylan present in plant cell walls. These compounds could function as C-sources for members of the intracellular clade. Molecular clock analysis indicated that the intracellular clade emerged ca. 600 Ma, suggesting that intracellular Nostoc symbioses predate the origin of land plants and the emergence of their extant hosts. PMID:29554291

Asaia symbionts interfere with infection by Flavescence dorée phytoplasma in leafhoppers

KAUST Repository

Gonella, Elena; Crotti, Elena; Mandrioli, Mauro; Daffonchio, Daniele; Alma, Alberto

2018-01-01

The transmission of microbial pathogens by insect vectors can be affected by the insect’s microbial symbionts, which may compete in colonizing organs, express antagonistic factors or activate host immune response. Acetic acid bacteria of the genus Asaia are symbionts of the leafhopper Scaphoideus titanus, which transmits Flavescence dorée phytoplasma. These bacteria could be used as control agents against the disease. Here, we experimentally investigated the interaction between different strains of Asaia and phytoplasma transmission in the laboratory by using the model leafhopper Euscelidius variegatus and the plant host Vicia faba. We found that uncultivable and low concentrations of Asaia phylotypes were associated with E. variegatus. When we supplied different Asaia strains isolated from other insects and exhibiting different phenotypes to E. variegatus orally, the bacteria stably colonized the leafhopper, reached relatively higher densities and could then be isolated from the host. We conducted transmission trials of Flavescence dorée phytoplasma with individuals colonized with three exogenous Asaia strains. When the phytoplasma became established in the bodies of E. variegatus, leafhoppers were able to transmit it to broad beans, with transmission rates ranging from 33 to 76% in different experiments. However, leafhoppers that were colonized by one of the Asaia strains producing an air–liquid interface biofilm exhibited significantly reduced phytoplasma acquisition, with infection rates at 5–28%, whereas they were 25–77% in control insects. Although the mechanisms regulating this interference remain to be elucidated, our results provide evidence of the potential use of Asaia as a biocontrol agent.

Asaia symbionts interfere with infection by Flavescence dorée phytoplasma in leafhoppers

KAUST Repository

Gonella, Elena

2018-03-20

The transmission of microbial pathogens by insect vectors can be affected by the insect’s microbial symbionts, which may compete in colonizing organs, express antagonistic factors or activate host immune response. Acetic acid bacteria of the genus Asaia are symbionts of the leafhopper Scaphoideus titanus, which transmits Flavescence dorée phytoplasma. These bacteria could be used as control agents against the disease. Here, we experimentally investigated the interaction between different strains of Asaia and phytoplasma transmission in the laboratory by using the model leafhopper Euscelidius variegatus and the plant host Vicia faba. We found that uncultivable and low concentrations of Asaia phylotypes were associated with E. variegatus. When we supplied different Asaia strains isolated from other insects and exhibiting different phenotypes to E. variegatus orally, the bacteria stably colonized the leafhopper, reached relatively higher densities and could then be isolated from the host. We conducted transmission trials of Flavescence dorée phytoplasma with individuals colonized with three exogenous Asaia strains. When the phytoplasma became established in the bodies of E. variegatus, leafhoppers were able to transmit it to broad beans, with transmission rates ranging from 33 to 76% in different experiments. However, leafhoppers that were colonized by one of the Asaia strains producing an air–liquid interface biofilm exhibited significantly reduced phytoplasma acquisition, with infection rates at 5–28%, whereas they were 25–77% in control insects. Although the mechanisms regulating this interference remain to be elucidated, our results provide evidence of the potential use of Asaia as a biocontrol agent.

Low levels of mitochondrial DNA and symbiont diversity in the worldwide agricultural pest, the greenhouse whitefly Trialeurodes vaporariorum (Hemiptera: Aleyrodidae).

Science.gov (United States)

Kapantaidaki, Despoina E; Ovčarenko, Irina; Fytrou, Natasa; Knott, K Emily; Bourtzis, Kostas; Tsagkarakou, Anastasia

2015-01-01

Trialeurodes vaporariorum, the greenhouse whitefly, is a cosmopolitan agricultural pest. Little is known about the genetic diversity of T. vaporariorum and the bacterial symbionts associated with this species. Here, we undertook a large phylogeographic study by investigating both the mitochondrial (mt) diversity and the infection status of 38 T. vaporariorum collections from 18 countries around the world. Genetic diversity of T. vaporariorum was studied by analyzing sequence data from the mt cytochrome oxidase I, cytochrome b, and NADH dehydrogenase subunit 5 genes. Maximum-likelihood (ML) phylogeny reconstruction delineated 2 clades characterized by limited sequence divergence: one clade comprised samples only from the Northern hemisphere whereas the other comprised samples from a broader geographical range. The presence of secondary symbionts was determined by PCR using primers specific for Hamiltonella, Rickettsia, Arsenophonus, Cardinium, Wolbachia, and Fritschea. Most individuals examined harbored at least one secondary endosymbiont, and Arsenophonus was detected in almost all male and female individuals. Wolbachia was present at a much lower frequency, and Cardinium was detected in only a few individuals from Greece. Rickettsia, Hamiltonella, and Fritschea were not found. Additionally, we set out to further analyze Arsenophonus diversity by multilocus sequence typing analysis; however, the Arsenophonus sequences did not exhibit any polymorphism. Our results revealed remarkably low diversity in both mtDNA and symbionts in this worldwide agricultural pest, contrasting sharply with that of the ecologically similar Bemisia tabaci. © The American Genetic Association 2014. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

PhaR, a Negative Regulator of PhaP, Modulates the Colonization of a Burkholderia Gut Symbiont in the Midgut of the Host Insect, Riptortus pedestris.

Science.gov (United States)

Jang, Seong Han; Jang, Ho Am; Lee, Junbeom; Kim, Jong Uk; Lee, Seung Ah; Park, Kyoung-Eun; Kim, Byung Hyun; Jo, Yong Hun; Lee, Bok Luel

2017-06-01

Five genes encoding PhaP family proteins and one phaR gene have been identified in the genome of Burkholderia symbiont strain RPE75. PhaP proteins function as the surface proteins of polyhydroxyalkanoate (PHA) granules, and the PhaR protein acts as a negative regulator of PhaP biosynthesis. Recently, we characterized one phaP gene to understand the molecular cross talk between Riptortus insects and Burkholderia gut symbionts. In this study, we constructed four other phaP gene-depleted mutants (Δ phaP1 , Δ phaP2 , Δ phaP3 , and Δ phaP4 mutants), one phaR gene-depleted mutant, and a phaR -complemented mutant (Δ phaR/phaR mutant). To address the biological roles of four phaP family genes and the phaR gene during insect-gut symbiont interaction, these Burkholderia mutants were fed to the second-instar nymphs, and colonization ability and fitness parameters were examined. In vitro , the Δ phaP3 and Δ phaR mutants cannot make a PHA granule normally in a stressful environment. Furthermore, the Δ phaR mutation decreased the colonization ability in the host midgut and negatively affected the host insect's fitness compared with wild-type Burkholderia -infected insects. However, other phaP family gene-depleted mutants colonized well in the midgut of the fifth-instar nymph insects. However, in the case of females, the colonization rate of the Δ phaP3 mutant was decreased and the host's fitness parameters were decreased compared with the wild-type-infected host, suggesting that the environment of the female midgut may be more hostile than that of the male midgut. These results demonstrate that PhaR plays an important role in the biosynthesis of PHA granules and that it is significantly related to the colonization of the Burkholderia gut symbiont in the host insects' midgut. IMPORTANCE Bacterial polyhydroxyalkanoate (PHA) biosynthesis is a complex process requiring several enzymes. The biological roles of PHA granule synthesis enzymes and the surface proteins of PHA

Genome sequence of Bradyrhizobium sp. LMTR 3, a diazotrophic symbiont of Lima bean (Phaseolus lunatus

Directory of Open Access Journals (Sweden)

Ernesto Ormeño-Orrillo

2017-09-01

Full Text Available Bradyrhizobium sp. LMTR 3 is a representative strain of one of the geno(species of diazotrophic symbionts associated with Lima bean (Phaseolus lunatus in Peru. Its 7.83 Mb genome was sequenced using the Illumina technology and found to encode a complete set of genes required for nodulation and nitrogen fixation, and additional genes putatively involved in root colonization. Its draft genome sequence and annotation have been deposited at GenBank under the accession number MAXC00000000.

Exploring the potential for actinobacteria as defensive symbionts in fungus-growing termites.

Science.gov (United States)

Visser, Anna A; Nobre, Tânia; Currie, Cameron R; Aanen, Duur K; Poulsen, Michael

2012-05-01

In fungus-growing termites, fungi of the subgenus Pseudoxylaria threaten colony health through substrate competition with the termite fungus (Termitomyces). The potential mechanisms with which termites suppress Pseudoxylaria have remained unknown. Here we explore if Actinobacteria potentially play a role as defensive symbionts against Pseudoxylaria in fungus-growing termites. We sampled for Actinobacteria from 30 fungus-growing termite colonies, spanning the three main termite genera and two geographically distant sites. Our isolations yielded 360 Actinobacteria, from which we selected subsets for morphological (288 isolates, grouped in 44 morphotypes) and for 16S rRNA (35 isolates, spanning the majority of morphotypes) characterisation. Actinobacteria were found throughout all sampled nests and colony parts and, phylogenetically, they are interspersed with Actinobacteria from origins other than fungus-growing termites, indicating lack of specificity. Antibiotic-activity screening of 288 isolates against the fungal cultivar and competitor revealed that most of the Actinobacteria-produced molecules with antifungal activity. A more detailed bioassay on 53 isolates, to test the specificity of antibiotics, showed that many Actinobacteria inhibit both Pseudoxylaria and Termitomyces, and that the cultivar fungus generally is more susceptible to inhibition than the competitor. This suggests that either defensive symbionts are not present in the system or that they, if present, represent a subset of the community isolated. If so, the antibiotics must be used in a targeted fashion, being applied to specific areas by the termites. We describe the first discovery of an assembly of antibiotic-producing Actinobacteria occurring in fungus-growing termite nests. However, due to the diversity found, and the lack of both phylogenetic and bioactivity specificity, further work is necessary for a better understanding of the putative role of antibiotic-producing bacteria in the fungus

Lifetime experience with (classic) psychedelics predicts pro-environmental behavior through an increase in nature relatedness.

Science.gov (United States)

Forstmann, Matthias; Sagioglou, Christina

2017-08-01

In a large-scale ( N = 1487) general population online study, we investigated the relationship between past experience with classic psychedelic substances (e.g. LSD, psilocybin, mescaline), nature relatedness, and ecological behavior (e.g. saving water, recycling). Using structural equation modeling we found that experience with classic psychedelics uniquely predicted self-reported engagement in pro-environmental behaviors, and that this relationship was statistically explained by people's degree of self-identification with nature. Our model controlled for experiences with other classes of psychoactive substances (cannabis, dissociatives, empathogens, popular legal drugs) as well as common personality traits that usually predict drug consumption and/or nature relatedness (openness to experience, conscientiousness, conservatism). Although correlational in nature, results suggest that lifetime experience with psychedelics in particular may indeed contribute to people's pro-environmental behavior by changing their self-construal in terms of an incorporation of the natural world, regardless of core personality traits or general propensity to consume mind-altering substances. Thereby, the present research adds to the contemporary literature on the beneficial effects of psychedelic substance use on mental wellbeing, hinting at a novel area for future research investigating their potentially positive effects on a societal level. Limitations of the present research and future directions are discussed.

Molecular analysis of immunoglobulin genes reveals frequent clonal relatedness in double monoclonal gammopathies.

Science.gov (United States)

Tschumper, R C; Dispenzieri, A; Abraham, R S; Henderson, K J; Jelinek, D F

2013-04-19

Monoclonal gammopathies (MGs) are hematological diseases characterized by high levels of a monoclonal immunoglobulin (Ig) or M-protein. Within this group are patients with more than one M-protein, referred to as double MGs (DMGs). The M-proteins in DMG patients may have different heavy chain (HC) isotypes that are associated with different light chains (LCs), or different HCs that are LC matched. In this study, we examined the clonal relatedness of the M-proteins in the latter type in a cohort of 14 DMG patients. By using PCR, we identified 7/14 DMG patients that expressed two Ig HC isotypes with identical Ig HC variable (IGHV), diversity (IGHD), joining (IGHJ), and complementarity determining region (HCDR3) sequences. Two additional DMG patients had two Ig transcripts using the same IGHV, IGHD and IGHJ genes but with slight differences in variable region or HCDR3 mutations. LC analysis confirmed that a single LC was expressed in 3/7 DMG patients with identical HC transcripts and in the two DMGs with highly similar transcripts. The PCR findings were confirmed by immunofluorescence for HC and LC expression. Clonally related HC-dissimilar/LC-matched DMGs may occur often and defines a new subtype of MG that may serve as a tool for studies of disease pathogenesis.

Molecular analysis of immunoglobulin genes reveals frequent clonal relatedness in double monoclonal gammopathies

International Nuclear Information System (INIS)

Tschumper, R C; Dispenzieri, A; Abraham, R S; Henderson, K J; Jelinek, D F

2013-01-01

Monoclonal gammopathies (MGs) are hematological diseases characterized by high levels of a monoclonal immunoglobulin (Ig) or M-protein. Within this group are patients with more than one M-protein, referred to as double MGs (DMGs). The M-proteins in DMG patients may have different heavy chain (HC) isotypes that are associated with different light chains (LCs), or different HCs that are LC matched. In this study, we examined the clonal relatedness of the M-proteins in the latter type in a cohort of 14 DMG patients. By using PCR, we identified 7/14 DMG patients that expressed two Ig HC isotypes with identical Ig HC variable (IGHV), diversity (IGHD), joining (IGHJ), and complementarity determining region (HCDR3) sequences. Two additional DMG patients had two Ig transcripts using the same IGHV, IGHD and IGHJ genes but with slight differences in variable region or HCDR3 mutations. LC analysis confirmed that a single LC was expressed in 3/7 DMG patients with identical HC transcripts and in the two DMGs with highly similar transcripts. The PCR findings were confirmed by immunofluorescence for HC and LC expression. Clonally related HC-dissimilar/LC-matched DMGs may occur often and defines a new subtype of MG that may serve as a tool for studies of disease pathogenesis

A general approach for haplotype phasing across the full spectrum of relatedness.

Directory of Open Access Journals (Sweden)

Jared O'Connell

2014-04-01

Full Text Available Many existing cohorts contain a range of relatedness between genotyped individuals, either by design or by chance. Haplotype estimation in such cohorts is a central step in many downstream analyses. Using genotypes from six cohorts from isolated populations and two cohorts from non-isolated populations, we have investigated the performance of different phasing methods designed for nominally 'unrelated' individuals. We find that SHAPEIT2 produces much lower switch error rates in all cohorts compared to other methods, including those designed specifically for isolated populations. In particular, when large amounts of IBD sharing is present, SHAPEIT2 infers close to perfect haplotypes. Based on these results we have developed a general strategy for phasing cohorts with any level of implicit or explicit relatedness between individuals. First SHAPEIT2 is run ignoring all explicit family information. We then apply a novel HMM method (duoHMM to combine the SHAPEIT2 haplotypes with any family information to infer the inheritance pattern of each meiosis at all sites across each chromosome. This allows the correction of switch errors, detection of recombination events and genotyping errors. We show that the method detects numbers of recombination events that align very well with expectations based on genetic maps, and that it infers far fewer spurious recombination events than Merlin. The method can also detect genotyping errors and infer recombination events in otherwise uninformative families, such as trios and duos. The detected recombination events can be used in association scans for recombination phenotypes. The method provides a simple and unified approach to haplotype estimation, that will be of interest to researchers in the fields of human, animal and plant genetics.

Semantic relatedness and similarity of biomedical terms: examining the effects of recency, size, and section of biomedical publications on the performance of word2vec.

Science.gov (United States)

Zhu, Yongjun; Yan, Erjia; Wang, Fei

2017-07-03

Understanding semantic relatedness and similarity between biomedical terms has a great impact on a variety of applications such as biomedical information retrieval, information extraction, and recommender systems. The objective of this study is to examine word2vec's ability in deriving semantic relatedness and similarity between biomedical terms from large publication data. Specifically, we focus on the effects of recency, size, and section of biomedical publication data on the performance of word2vec. We download abstracts of 18,777,129 articles from PubMed and 766,326 full-text articles from PubMed Central (PMC). The datasets are preprocessed and grouped into subsets by recency, size, and section. Word2vec models are trained on these subtests. Cosine similarities between biomedical terms obtained from the word2vec models are compared against reference standards. Performance of models trained on different subsets are compared to examine recency, size, and section effects. Models trained on recent datasets did not boost the performance. Models trained on larger datasets identified more pairs of biomedical terms than models trained on smaller datasets in relatedness task (from 368 at the 10% level to 494 at the 100% level) and similarity task (from 374 at the 10% level to 491 at the 100% level). The model trained on abstracts produced results that have higher correlations with the reference standards than the one trained on article bodies (i.e., 0.65 vs. 0.62 in the similarity task and 0.66 vs. 0.59 in the relatedness task). However, the latter identified more pairs of biomedical terms than the former (i.e., 344 vs. 498 in the similarity task and 339 vs. 503 in the relatedness task). Increasing the size of dataset does not always enhance the performance. Increasing the size of datasets can result in the identification of more relations of biomedical terms even though it does not guarantee better precision. As summaries of research articles, compared with article

Integrating microRNA and mRNA expression profiling in Symbiodinium microadriaticum, a dinoflagellate symbiont of reef-building corals.

KAUST Repository

Baumgarten, Sebastian

2013-10-12

Animal and plant genomes produce numerous small RNAs (smRNAs) that regulate gene expression post-transcriptionally affecting metabolism, development, and epigenetic inheritance. In order to characterize the repertoire of endogenous smRNAs and potential gene targets in dinoflagellates, we conducted smRNA and mRNA expression profiling over 9 experimental treatments of cultures from Symbiodinium microadriaticum, a photosynthetic symbiont of scleractinian corals.

Integrating microRNA and mRNA expression profiling in Symbiodinium microadriaticum, a dinoflagellate symbiont of reef-building corals.

KAUST Repository

Baumgarten, Sebastian; Bayer, Till; Aranda, Manuel; Liew, Yi Jin; Carr, Adrian; Micklem, Gos; Voolstra, Christian R.

2013-01-01

Animal and plant genomes produce numerous small RNAs (smRNAs) that regulate gene expression post-transcriptionally affecting metabolism, development, and epigenetic inheritance. In order to characterize the repertoire of endogenous smRNAs and potential gene targets in dinoflagellates, we conducted smRNA and mRNA expression profiling over 9 experimental treatments of cultures from Symbiodinium microadriaticum, a photosynthetic symbiont of scleractinian corals.

Genome-wide SNPs lead to strong signals of geographic structure and relatedness patterns in the major arbovirus vector, Aedes aegypti.

Science.gov (United States)

Rašić, Gordana; Filipović, Igor; Weeks, Andrew R; Hoffmann, Ary A

2014-04-11

Genetic markers are widely used to understand the biology and population dynamics of disease vectors, but often markers are limited in the resolution they provide. In particular, the delineation of population structure, fine scale movement and patterns of relatedness are often obscured unless numerous markers are available. To address this issue in the major arbovirus vector, the yellow fever mosquito (Aedes aegypti), we used double digest Restriction-site Associated DNA (ddRAD) sequencing for the discovery of genome-wide single nucleotide polymorphisms (SNPs). We aimed to characterize the new SNP set and to test the resolution against previously described microsatellite markers in detecting broad and fine-scale genetic patterns in Ae. aegypti. We developed bioinformatics tools that support the customization of restriction enzyme-based protocols for SNP discovery. We showed that our approach for RAD library construction achieves unbiased genome representation that reflects true evolutionary processes. In Ae. aegypti samples from three continents we identified more than 18,000 putative SNPs. They were widely distributed across the three Ae. aegypti chromosomes, with 47.9% found in intergenic regions and 17.8% in exons of over 2,300 genes. Pattern of their imputed effects in ORFs and UTRs were consistent with those found in a recent transcriptome study. We demonstrated that individual mosquitoes from Indonesia, Australia, Vietnam and Brazil can be assigned with a very high degree of confidence to their region of origin using a large SNP panel. We also showed that familial relatedness of samples from a 0.4 km2 area could be confidently established with a subset of SNPs. Using a cost-effective customized RAD sequencing approach supported by our bioinformatics tools, we characterized over 18,000 SNPs in field samples of the dengue fever mosquito Ae. aegypti. The variants were annotated and positioned onto the three Ae. aegypti chromosomes. The new SNP set provided much

Genetic and genomic diversity studies of Acacia symbionts in Senegal reveal new species of Mesorhizobium with a putative geographical pattern.

Directory of Open Access Journals (Sweden)

Fatou Diouf

Full Text Available Acacia senegal (L Willd. and Acacia seyal Del. are highly nitrogen-fixing and moderately salt tolerant species. In this study we focused on the genetic and genomic diversity of Acacia mesorhizobia symbionts from diverse origins in Senegal and investigated possible correlations between the genetic diversity of the strains, their soil of origin, and their tolerance to salinity. We first performed a multi-locus sequence analysis on five markers gene fragments on a collection of 47 mesorhizobia strains of A. senegal and A. seyal from 8 localities. Most of the strains (60% clustered with the M. plurifarium type strain ORS 1032T, while the others form four new clades (MSP1 to MSP4. We sequenced and assembled seven draft genomes: four in the M. plurifarium clade (ORS3356, ORS3365, STM8773 and ORS1032T, one in MSP1 (STM8789, MSP2 (ORS3359 and MSP3 (ORS3324. The average nucleotide identities between these genomes together with the MLSA analysis reveal three new species of Mesorhizobium. A great variability of salt tolerance was found among the strains with a lack of correlation between the genetic diversity of mesorhizobia, their salt tolerance and the soils samples characteristics. A putative geographical pattern of A. senegal symbionts between the dryland north part and the center of Senegal was found, reflecting adaptations to specific local conditions such as the water regime. However, the presence of salt does not seem to be an important structuring factor of Mesorhizobium species.

A fungal root symbiont modifies plant resistance to an insect herbivore.

Science.gov (United States)

Borowicz, Victoria A

1997-11-01

Vesicular-arbuscular mycorrhizal (VAM) fungi are common root-colonizing symbionts that affect nutrient uptake by plants and can alter plant susceptibility to herbivores. I conducted a factorial experiment to test the hypotheses that colonization by VAM fungi (1) improves soybean (Glycine max) tolerance to grazing by folivorous Mexican bean beetle (Epilachna varivestis), and (2) indirectly affects herbivores by increasing host resistance. Soybean seedlings were inoculated with the VAM fungus Glomus etunicatum or VAM-free filtrate and fertilized with high-[P] or low-[P] fertilizer. After plants had grown for 7 weeks first-instar beetle larvae were placed on bagged leaves. Growth of soybean was little affected by grazing larvae, and no effects of treatments on tolerance of soybeans to herbivores were evident. Colonization by VAM fungus doubled the size of phosphorus-stressed plants but these plants were still half the size of plants given adequate phosphorus. High-[P] fertilizer increased levels of phosphorus and soluble carbohydrates, and decreased levels of soluble proteins in leaves of grazed plants. Colonization of grazed plants by VAM fungus had no significant effect on plant soluble carbohydrates, but increased concentration of phosphorus and decreased levels of proteins in phosphorus-stressed plants to concentrations similar to those of plants given adequate phosphorus. Mexican bean beetle mass at pupation, pupation rate, and survival to eclosion were greatest for beetles reared on phosphorus-stressed, VAM-colonized plants, refuting the hypothesis that VAM colonization improves host plant resistance. VAM colonization indirectly affected performance of Mexician bean beetle larvae by improving growth and nutrition of the host plant.

The effects of elevated seawater temperatures on Caribbean gorgonian corals and their algal symbionts, Symbiodinium spp.

Directory of Open Access Journals (Sweden)

Tamar L Goulet

Full Text Available Global climate change not only leads to elevated seawater temperatures but also to episodic anomalously high or low temperatures lasting for several hours to days. Scleractinian corals are detrimentally affected by thermal fluctuations, which often lead to an uncoupling of their mutualism with Symbiodinium spp. (coral bleaching and potentially coral death. Consequently, on many Caribbean reefs scleractinian coral cover has plummeted. Conversely, gorgonian corals persist, with their abundance even increasing. How gorgonians react to thermal anomalies has been investigated utilizing limited parameters of either the gorgonian, Symbiodinium or the combined symbiosis (holobiont. We employed a holistic approach to examine the effect of an experimental five-day elevated temperature episode on parameters of the host, symbiont, and the holobiont in Eunicea tourneforti, E. flexuosa and Pseudoplexaura porosa. These gorgonian corals reacted and coped with 32°C seawater temperatures. Neither Symbiodinium genotypes nor densities differed between the ambient 29.5°C and 32°C. Chlorophyll a and c2 per Symbiodinium cell, however, were lower at 32°C leading to a reduction in chlorophyll content in the branches and an associated reduction in estimated absorbance and increase in the chlorophyll a specific absorption coefficient. The adjustments in the photochemical parameters led to changes in photochemical efficiencies, although these too showed that the gorgonians were coping. For example, the maximum excitation pressure, Qm, was significantly lower at 32°C than at 29.5°C. In addition, although per dry weight the amount of protein and lipids were lower at 32°C, the overall energy content in the tissues did not differ between the temperatures. Antioxidant activity either remained the same or increased following exposure to 32°C further reiterating a response that dealt with the stressor. Taken together, the capability of Caribbean gorgonian corals to modify

Functional and phylogenetic relatedness in temporary wetland invertebrates: current macroecological patterns and implications for future climatic change scenarios.

Science.gov (United States)

Ruhí, Albert; Boix, Dani; Gascón, Stéphanie; Sala, Jordi; Batzer, Darold P

2013-01-01

In freshwater ecosystems, species compositions are known to be determined hierarchically by large to small‑scale environmental factors, based on the biological traits of the organisms. However, in ephemeral habitats this heuristic framework remains largely untested. Although temporary wetland faunas are constrained by a local filter (i.e., desiccation), we propose its magnitude may still depend on large-scale climate characteristics. If this is true, climate should be related to the degree of functional and taxonomic relatedness of invertebrate communities inhabiting seasonal wetlands. We tested this hypothesis in two ways. First, based on 52 biological traits for invertebrates, we conducted a case study to explore functional trends among temperate seasonal wetlands differing in the harshness (i.e., dryness) of their dry season. After finding evidence of trait filtering, we addressed whether it could be generalized across a broader climatic scale. To this end, a meta-analysis (225 seasonal wetlands spread across broad climatic categories: Arid, Temperate, and Cold) allowed us to identify whether an equivalent climate-dependent pattern of trait richness was consistent between the Nearctic and the Western Palearctic. Functional overlap of invertebrates increased from mild (i.e., Temperate) to harsher climates (i.e., Arid and Cold), and phylogenetic clustering (using taxonomy as a surrogate) was highest in Arid and lowest in Temperate wetlands. We show that, (i) as has been described in streams, higher relatedness than would be expected by chance is generally observed in seasonal wetland invertebrate communities; and (ii) this relatedness is not constant but climate-dependent, with the climate under which a given seasonal wetland is located determining the functional overlap and the phylogenetic clustering of the community. Finally, using a space-for-time substitution approach we suggest our results may anticipate how the invertebrate biodiversity embedded in these

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

DEFF Research Database (Denmark)

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

2010-01-01

, and the highest species diversity and cell concentrations were found at temperatures around 20 to 30°C. The symbiont-bearing dinoflagellates were always associated with water masses with low nutrient (N-limited) and chl a concentrations. Special attention was given to the ectosymbiont-bearing dinoflagellates....... Under light microscopy, some of the food vacuoles of Ornithocercus spp. resembled ectosymbionts in size, shape and colour. Transmission electron microscopy of O. magnificus and O. quadratus revealed the presence of a peduncle and many rhabdosomes; both may serve in prey capture. Also, numerous food...

Exploring the potential for actinobacteria as defensive symbionts in fungus-growing termites

DEFF Research Database (Denmark)

Visser, Anna A.; Nobre, Tânia; Currie, Cameron R.

2012-01-01

In fungus-growing termites, fungi of the subgenus Pseudoxylaria threaten colony health through substrate competition with the termite fungus (Termitomyces). The potential mechanisms with which termites suppress Pseudoxylaria have remained unknown. Here we explore if Actinobacteria potentially play...... a role as defensive symbionts against Pseudoxylaria in fungus-growing termites. We sampled for Actinobacteria from 30 fungus-growing termite colonies, spanning the three main termite genera and two geographically distant sites. Our isolations yielded 360 Actinobacteria, from which we selected subsets...... for morphological (288 isolates, grouped in 44 morphotypes) and for 16S rRNA (35 isolates, spanning the majority of morphotypes) characterisation. Actinobacteria were found throughout all sampled nests and colony parts and, phylogenetically, they are interspersed with Actinobacteria from origins other than fungus...

Complete Genome sequence of Burkholderia phymatum STM815, a broad host range and efficient nitrogen-fixing symbiont of Mimosa species

Energy Technology Data Exchange (ETDEWEB)

Moulin, Lionel [UMR, France; Klonowska, Agnieszka [UMR, France; Caroline, Bournaud [UMR, France; Booth, Kristina [University of Massachusetts; Vriezen, Jan A.C. [University of Massachusetts; Melkonian, Remy [UMR, France; James, Euan [James Hutton Institute, Dundee, United Kingdom; Young, Peter W. [University of York, United Kingdom; Bena, Gilles [UMR, France; Hauser, Loren John [ORNL; Land, Miriam L [ORNL; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Bruce, David [Los Alamos National Laboratory (LANL); Chain, Patrick S. G. [Lawrence Livermore National Laboratory (LLNL); Copeland, A [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [U.S. Department of Energy, Joint Genome Institute; Woyke, Tanja [U.S. Department of Energy, Joint Genome Institute; Lizotte-Waniewski, Michelle [University of Massachusetts; Bristow, James [U.S. Department of Energy, Joint Genome Institute; Riley, Monica [Woods Hole Oceanographic Institution (WHOI), Woods Hole

2014-01-01

Burkholderia phymatum is a soil bacterium able to develop a nitrogen-fixing symbiosis with species of the legume genus Mimosa, and is frequently found associated specifically with Mimosa pudica. The type strain of the species, STM 815T, was isolated from a root nodule in French Guiana in 2000. The strain is an aerobic, motile, non-spore forming, Gram-negative rod, and is a highly competitive strain for nodulation compared to other Mimosa symbionts, as it also nodulates a broad range of other legume genera and species. The 8,676,562 bp genome is composed of two chromosomes (3,479,187 and 2,697,374 bp), a megaplasmid (1,904,893 bp) and a plasmid hosting the symbiotic functions (595,108 bp).

The Development of Self-Definition and Relatedness in Emerging Adulthood and Their Role in the Development of Depressive Symptoms

Science.gov (United States)

Kopala-Sibley, Daniel C.; Zuroff, David C.; Hermanto, Nicola; Joyal-Desmarais, Keven

2016-01-01

According to Blatt (2004; Blatt & Luyten, 2009) and others (e.g., Beck, Epstein, Harrison, & Emery, 1983), establishing positive self-definition and mature relatedness to others represent core lifespan developmental tasks. In a sample of emerging adults, this study examined the effects of the quality of one close friendship and changes in…

Condition-specific RNA editing in the coral symbiont Symbiodinium microadriaticum

KAUST Repository

Liew, Yi Jin

2017-03-01

RNA editing is a rare post-transcriptional event that provides cells with an additional level of gene expression regulation. It has been implicated in various processes including adaptation, viral defence and RNA interference; however, its potential role as a mechanism in acclimatization has just recently been recognised. Here, we show that RNA editing occurs in 1.6% of all nuclear-encoded genes of Symbiodinium microadriaticum, a dinoflagellate symbiont of reef-building corals. All base-substitution edit types were present, and statistically significant motifs were associated with three edit types. Strikingly, a subset of genes exhibited condition-specific editing patterns in response to different stressors that resulted in significant increases of non-synonymous changes. We posit that this previously unrecognised mechanism extends this organism’s capability to respond to stress beyond what is encoded by the genome. This in turn may provide further acclimatization capacity to these organisms, and by extension, their coral hosts.

Condition-specific RNA editing in the coral symbiont Symbiodinium microadriaticum

KAUST Repository

Liew, Yi Jin; Li, Yong; Baumgarten, Sebastian; Voolstra, Christian R.; Aranda, Manuel

2017-01-01

RNA editing is a rare post-transcriptional event that provides cells with an additional level of gene expression regulation. It has been implicated in various processes including adaptation, viral defence and RNA interference; however, its potential role as a mechanism in acclimatization has just recently been recognised. Here, we show that RNA editing occurs in 1.6% of all nuclear-encoded genes of Symbiodinium microadriaticum, a dinoflagellate symbiont of reef-building corals. All base-substitution edit types were present, and statistically significant motifs were associated with three edit types. Strikingly, a subset of genes exhibited condition-specific editing patterns in response to different stressors that resulted in significant increases of non-synonymous changes. We posit that this previously unrecognised mechanism extends this organism’s capability to respond to stress beyond what is encoded by the genome. This in turn may provide further acclimatization capacity to these organisms, and by extension, their coral hosts.

Dead or Alive? Knowledge about a Sibling's Death Varies by Genetic Relatedness in a Modern Society

Directory of Open Access Journals (Sweden)

Thomas V. Pollet

2009-01-01

Full Text Available Using a large sample of non-institutionalized individuals from the Netherlands (n = 7610, we examined the influence of relatedness on an individual's knowledge about whether their sibling is alive or not. Respondents were generally less likely to know whether their sibling was alive if they were not fully related. The effects were stronger for differences between paternal half-siblings and full siblings than for differences between maternal half-siblings and full siblings.

Dead or Alive? Knowledge about a Sibling's Death Varies by Genetic Relatedness in a Modern Society

OpenAIRE

Pollet, Thomas; Nettle, Daniel

2009-01-01

Using a large sample of non-institutionalized individuals from the Netherlands (n = 7610), we examined the influence of relatedness on an individual's knowledge about whether their sibling is alive or not. Respondents were generally less likely to know whether their sibling was alive if they were not fully related. The effects were stronger for differences between paternal half-siblings and full siblings than for differences between maternal half-siblings and full siblings.

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

Science.gov (United States)

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

2016-02-01

The symbiotic dinoflagellate Gymnoxanthella radiolariae T. Yuasa et T. Horiguchi gen. et sp. nov. isolated from polycystine radiolarians is described herein based on light, scanning and transmission electron microscopy as well as molecular phylogenetic analyses of SSU and LSU rDNA sequences. Motile cells of G. radiolariae were obtained in culture, and appeared to be unarmored. The cells were 9.1-11.4 μm long and 5.7-9.4 μm wide, and oval to elongate oval in the ventral view. They possessed an counterclockwise horseshoe-shaped apical groove, a nuclear envelope with vesicular chambers, cingulum displacement with one cingulum width, and the nuclear fibrous connective; all of these are characteristics of Gymnodinium sensu stricto (Gymnodinium s.s.). Molecular phylogenetic analyses also indicated that G. radiolariae belongs to the clade of Gymnodinium s.s. However, in our molecular phylogenetic trees, G. radiolariae was distantly related to Gymnodinium fuscum, the type species of Gymnodinium. Based on the consistent morphological, genetic, and ecological divergence of our species with the other genera and species of Gymnodinium s.s., we considered it justified to erect a new, separate genus and species G. radiolariae gen. et sp. nov. As for the peridinioid symbiont of radiolarians, Brandtodinium has been erected as a new genus instead of Zooxanthella, but the name Zooxanthella is still valid. Brandtodinium is a junior synonym of Zooxanthella. Our results suggest that at least two dinoflagellate symbiont species, peridinioid Zooxanthella nutricula and gymnodinioid G. radiolariae, exist in radiolarians, and that they may have been mixed and reported as "Z. nutricula" since the 19th century. © 2016 Phycological Society of America.

Taxonomy and phylogeny of a new kleptoplastidal dinoflagellate, Gymnodinium myriopyrenoides sp. nov. (Gymnodiniales, Dinophyceae), and its cryptophyte symbiont.

Science.gov (United States)

Yamaguchi, Haruyo; Nakayama, Takeshi; Kai, Atsushi; Inouye, Isao

2011-10-01

A new kleptoplastidal dinoflagellate, Gymnodinium myriopyrenoides sp. nov., was described using light microscopy, electron microscopy and phylogengetic analysis based on partial LSU rDNA sequences. Cells were dorsiventrally flattened, elongate-elliptical in ventral view. There was no displacement of the cingulum encircling the anterior part of the cell. The cingulum was curved posteriorly at the terminal junction with the sulcus. The sulcus was generally narrow but expanded in the posterior end. The epicone possessed an apical groove made of one and one-half counterclockwise revolutions. Phylogenetic analysis based on LSU rDNA showed that the sequence of G. myriopyrenoides was included in the Gymnodiniales sensu stricto clade and had special affinities with the species Amphidinium poecilochroum and Gymnodinium acidotum, which also harbor kleptochloroplasts. Phylogenetic analysis based on plastid-encoded SSU rDNA and ultrastructural observations suggested that the symbionts of G. myriopyrenoides were cryptophytes of the genus Chroomonas or Hemiselmis. Organelles including the nucleus, the nucleomorph, mitochondria, Golgi bodies and large chloroplasts remained in the cytoplasm of the symbionts, but not the periplast, ejectosomes or flagellar apparatus. The symbiotic level of G. myriopyrenoides was estimated to be a relatively early stage in the unarmored kleptoplastidal dinoflagellates. Copyright © 2011 Elsevier GmbH. All rights reserved.

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

KAUST Repository

Lee, O. O.

2009-07-31

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

Influence of Multiple Infection and Relatedness on Virulence: Disease Dynamics in an Experimental Plant Population and Its Castrating Parasite

Science.gov (United States)

Buono, Lorenza; López-Villavicencio, Manuela; Shykoff, Jacqui A.; Snirc, Alodie; Giraud, Tatiana

2014-01-01

The level of parasite virulence, i.e., the decrease in host's fitness due to a pathogen, is expected to depend on several parameters, such as the type of the disease (e.g., castrating or host-killing) and the prevalence of multiple infections. Although these parameters have been extensively studied theoretically, few empirical data are available to validate theoretical predictions. Using the anther smut castrating disease on Silene latifolia caused by Microbotryum lychnidis-dioicae, we studied the dynamics of multiple infections and of different components of virulence (host death, non-recovery and percentage of castrated stems) during the entire lifespan of the host in an experimental population. We monitored the number of fungal genotypes within plants and their relatedness across five years, using microsatellite markers, as well as the rates of recovery and host death in the population. The mean relatedness among genotypes within plants remained at a high level throughout the entire host lifespan despite the dynamics of the disease, with recurrent new infections. Recovery was lower for plants with multiple infections compared to plants infected by a single genotype. As expected for castrating parasites, M. lychnidis-dioicae did not increase host mortality. Mortality varied across years but was generally lower for plants that had been diseased the preceding year. This is one of the few studies to have empirically verified theoretical expectations for castrating parasites, and to show particularly i) that castrated hosts live longer, suggesting that parasites can redirect resources normally used in reproduction to increase host lifespan, lengthening their transmission phase, and ii) that multiple infections increase virulence, here in terms of non-recovery and host castration. PMID:24892951

Fine-Scale Biogeographical Boundary Delineation and Sub-population Resolution in the Symbiodinium thermophilum Coral Symbiont Group From the Persian/Arabian Gulf and Gulf of Oman

KAUST Repository

Hume, Benjamin C. C.; D'Angelo, Cecilia; Burt, John A.; Wiedenmann, Jö rg

2018-01-01

The adaptation of tropical coral communities to the world's hottest sea, the Persian/Arabian Gulf (PAG), has recently been associated with ecological selection acting on a group of coral-associated algal symbionts, the Symbiodinium thermophilum

Bacteriocins with a broader antimicrobial spectrum prevail in enterococcal symbionts isolated from the hoopoe's uropygial gland.

Science.gov (United States)

Ruiz-Rodríguez, Magdalena; Martínez-Bueno, Manuel; Martín-Vivaldi, Manuel; Valdivia, Eva; Soler, Juan J

2013-09-01

The use of compounds produced by symbiotic bacteria against pathogens in animals is one of the most exciting discoveries in ecological immunology. The study of those antibiotic metabolites will enable an understanding of the defensive strategies against pathogenic infections. Here, we explore the role of bacteriocins explaining the antimicrobial properties of symbiotic bacteria isolated from the uropygial gland of the hoopoe (Upupa epops). The antagonistic activity of 187 strains was assayed against eight indicator bacteria, and the presence of six bacteriocin genes was detected in the genomic DNA. The presence of bacteriocin genes correlated with the antimicrobial activity of isolates. The most frequently detected bacteriocin genes were those encoding for the MR10 and AS-48 enterocins, which confer the highest inhibition capacity. All the isolates belonged to the genus Enterococcus, with E. faecalis as the most abundant species, with the broadest antimicrobial spectrum and the highest antagonistic activity. The vast majority of E. faecalis strains carried the genes of MR10 and AS-48 in their genome. Therefore, we suggest that fitness-related benefits for hoopoes associated with harbouring the most bactericidal symbionts cause the highest frequency of strains carrying MR10 and AS-48 genes. The study of mechanisms associated with the acquisition and selection of bacterial symbionts by hoopoes is necessary, however, to reach further conclusions. © 2013 Federation of European Microbiological Societies. Published by John Wiley & Sons Ltd. All rights reserved.

Elucidating the neural correlates of related false memories using a systematic measure of perceptual relatedness.

Science.gov (United States)

Turney, Indira C; Dennis, Nancy A

2017-02-01

Previous memory research has exploited the perceptual similarities between lures and targets in order to evoke false memories. Nevertheless, while some studies have attempted to use lures that are objectively more similar than others, no study has systematically controlled for perceptual overlap between target and lure items and its role in accounting for false alarm rates or the neural processes underlying such perceptual false memories. The current study looked to fill this gap in the literature by using a face-morphing program to systematically control for the amount of perceptual overlap between lures and targets. Our results converge with previous studies in finding a pattern of differences between true and false memories. Most importantly, expanding upon this work, parametric analyses showed false memory activity increases with respect to the similarity between lures and targets within bilateral middle temporal gyri and right medial prefrontal cortex (mPFC). Moreover, this pattern of activation was unique to false memories and could not be accounted for by relatedness alone. Connectivity analyses further find that activity in the mPFC and left middle temporal gyrus co-vary, suggestive of gist-based monitoring within the context of false memories. Interestingly, neither the MTL nor the fusiform face area exhibited modulation as a function of target-lure relatedness. Overall, these results provide insight into the processes underlying false memories and further enhance our understanding of the role perceptual similarity plays in supporting false memories. Copyright © 2016 Elsevier Inc. All rights reserved.

Identification of a common cyanobacterial symbiont associated with Azolla spp. through molecular and morphological characterization of free-living and symbiotic cyanobacteria.

Science.gov (United States)

Gebhardt, J S; Nierzwicki-Bauer, S A

1991-01-01

Symbiotically associated cyanobacteria from Azolla mexicana and Azolla pinnata were isolated and cultured in a free-living state. Morphological analyses revealed differences between the free-living isolates and their symbiotic counterparts, as did restriction fragment length polymorphism (RFLP) analyses with both single-copy glnA and rbcS gene probes and a multicopy psbA gene probe. RFLP analyses with Anabaena sp. strain PCC 7120 nifD excision element probes, including an xisA gene probe, detected homologous sequences in DNA extracted from the free-living isolates. Sequences homologous to these probes were not detected in DNA from the symbiotically associated cyanobacteria. These analyses indicated that the isolates were not identical to the major cyanobacterial symbiont species residing in leaf cavities of Azolla spp. Nevertheless, striking similarities between several free-living isolates were observed. In every instance, the isolate from A. pinnata displayed banding patterns virtually identical to those of free-living cultures previously isolated from Azolla caroliniana and Azolla filiculoides. These results suggest the ubiquitous presence of a culturable minor cyanobacterial symbiont in at least three species of Azolla. Images PMID:1685078

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

Science.gov (United States)

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

2017-09-08

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

Honey bees consider larval nutritional status rather than genetic relatedness when selecting larvae for emergency queen rearing.

Science.gov (United States)

Sagili, Ramesh R; Metz, Bradley N; Lucas, Hannah M; Chakrabarti, Priyadarshini; Breece, Carolyn R

2018-05-16

In honey bees and many other social insects, production of queens is a vital task, as colony fitness is dependent on queens. The factors considered by honey bee workers in selecting larvae to rear new queens during emergency queen rearing are poorly understood. Identifying these parameters is critical, both in an evolutionary and apicultural context. As female caste development in honey bees is dependent on larval diet (i.e. nutrition), we hypothesized that larval nutritional state is meticulously assessed and used by workers in selection of larvae for queen rearing. To test this hypothesis, we conducted a series of experiments manipulating the nutritional status of one day old larvae by depriving them of brood food for a four-hour period, and then allowing workers to choose larvae for rearing queens from nutritionally deprived and non-deprived larvae. We simultaneously investigated the role of genetic relatedness in selection of larvae for queen rearing. In all the experiments, significantly greater numbers of non-deprived larvae than deprived larvae were selected for queen rearing irrespective of genetic relatedness. Our results demonstrate that honey bees perceive the nutritional state of larvae and use that information when selecting larvae for rearing queens in the natural emergency queen replacement process.

Alder and the Golden Fleece: high diversity of Frankia and ectomycorrhizal fungi revealed from Alnus glutinosa subsp. barbata roots close to a Tertiary and glacial refugium

Directory of Open Access Journals (Sweden)

Melanie Roy

2017-07-01

Full Text Available Background Recent climatic history has strongly impacted plant populations, but little is known about its effect on microbes. Alders, which host few and specific symbionts, have high genetic diversity in glacial refugia. Here, we tested the prediction that communities of root symbionts survived in refugia with their host populations. We expected to detect endemic symbionts and a higher species richness in refugia as compared to recolonized areas. Methods We sampled ectomycorrhizal (EM root tips and the nitrogen-fixing actinomycete Frankia communities in eight sites colonized by Alnus glutinosa subsp. barbata close to the Caucasus in Georgia. Three sites were located in the Colchis, one major Eurasian climatic refugia for Arcto-Tertiary flora and alders, and five sites were located in the recolonized zone. Endemic symbionts and plant ITS variants were detected by comparing sequences to published data from Europe and another Tertiary refugium, the Hyrcanian forest. Species richness and community structure were compared between sites from refugia and recolonized areas for each symbionts. Results For both symbionts, most MOTUs present in Georgia had been found previously elsewhere in Europe. Three endemic Frankia strains were detected in the Colchis vs two in the recolonized zone, and the five endemic EM fungi were detected only in the recolonized zone. Frankia species richness was higher in the Colchis while the contrary was observed for EM fungi. Moreover, the genetic diversity of one alder specialist Alnicola xanthophylla was particularly high in the recolonized zone. The EM communities occurring in the Colchis and the Hyrcanian forests shared closely related endemic species. Discussion The Colchis did not have the highest alpha diversity and more endemic species, suggesting that our hypothesis based on alder biogeography may not apply to alder’s symbionts. Our study in the Caucasus brings new clues to understand symbioses biogeography and

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

Directory of Open Access Journals (Sweden)

Karin Aistleitner

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

Resting state glutamate predicts elevated pre-stimulus alpha during self-relatedness: A combined EEG-MRS study on "rest-self overlap".

Science.gov (United States)

Bai, Yu; Nakao, Takashi; Xu, Jiameng; Qin, Pengmin; Chaves, Pedro; Heinzel, Alexander; Duncan, Niall; Lane, Timothy; Yen, Nai-Shing; Tsai, Shang-Yueh; Northoff, Georg

2016-01-01

Recent studies have demonstrated neural overlap between resting state activity and self-referential processing. This "rest-self" overlap occurs especially in anterior cortical midline structures like the perigenual anterior cingulate cortex (PACC). However, the exact neurotemporal and biochemical mechanisms remain to be identified. Therefore, we conducted a combined electroencephalography (EEG)-magnetic resonance spectroscopy (MRS) study. EEG focused on pre-stimulus (e.g., prior to stimulus presentation or perception) power changes to assess the degree to which those changes can predict subjects' perception (and judgment) of subsequent stimuli as high or low self-related. MRS measured resting state concentration of glutamate, focusing on PACC. High pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power significantly correlated with both perception of stimuli judged to be highly self-related and with resting state glutamate concentrations in the PACC. In sum, our results show (i) pre-stimulus (e.g., prior to stimulus presentation or perception) alpha power and resting state glutamate concentration to mediate rest-self overlap that (ii) dispose or incline subjects to assign high degrees of self-relatedness to perceptual stimuli.

Students' Perceptions of Social Relatedness in the Classroom: The Roles of Student-Teacher Interaction Quality, Children's Aggressive Behaviors, and Peer Rejection

Science.gov (United States)

Madill, Rebecca A.; Gest, Scott D.; Rodkin, Philip C.

2011-01-01

This study contributes to the literature clarifying teaching practices in elementary classrooms that promote students' social relatedness. The focus on teaching practices reflects the need to understand malleable elements of the classroom, which can then be targeted for professional development. Specifically, this study examines whether children…

Mycorrhizal symbionts of Pisonia grandis and P. sechellarum in Seychelles: identification of mycorrhizal fungi and description of new Tomentella species.

Science.gov (United States)

Suvi, Triin; Tedersoo, Leho; Abarenkov, Kessy; Beaver, Katy; Gerlach, Justin; Kõljalg, Urmas

2010-01-01

Nyctaginaceae includes species that are predominantly non-mycorrhizal or form arbuscular or ectomycorrhiza. Root-associated fungi were studied from P. grandis and P. sechellarum roots collected respectively on the islands of Cousin and Silhouette in Seychelles. In addition fungal sporocarps were collected from the sampling area. Fungal symbionts were identified from the roots by anatomotyping and rDNA sequencing; sporocarps collected were examined microscopically and sequenced. Three distantly related ectomycorrhizal fungal species belonging to Thelephoraceae were identified from the roots of P. grandis. Sporocarps also were found for two symbionts and described as new Tomentella species. In addition Tomentella species collected from other Seychelles islands were studied and described as new species if there was no close resemblance to previously established species. P. sechellarum was determined to be an arbuscular mycorrhizal plant; three arbuscular mycorrhizal fungal species were detected from the roots. P. grandis is probably associated only with species of Thelephoraceae throughout its area. Only five Tomentella species are known to form ectomycorrhiza with P. grandis and they never have been found to be associated with another host, suggesting adaptation of these fungi to extreme environmental conditions in host's habitat.

Reciprocal immune benefit based on complementary production of antibiotics by the leech Hirudo verbana and its gut symbiont Aeromonas veronii.

Science.gov (United States)

Tasiemski, Aurélie; Massol, François; Cuvillier-Hot, Virginie; Boidin-Wichlacz, Céline; Roger, Emmanuel; Rodet, Franck; Fournier, Isabelle; Thomas, Frédéric; Salzet, Michel

2015-12-04

The medicinal leech has established a long-term mutualistic association with Aeromonas veronii, a versatile bacterium which can also display free-living waterborne and fish- or human-pathogenic lifestyles. Here, we investigated the role of antibiotics in the dynamics of interaction between the leech and its gut symbiont Aeromonas. By combining biochemical and molecular approaches, we isolated and identified for the first time the antimicrobial peptides (AMPs) produced by the leech digestive tract and by its symbiont Aeromonas. Immunohistochemistry data and PCR analyses evidenced that leech AMP genes are induced in the gut epithelial cells when Aeromonas load is low (starved animals), while repressed when Aeromonas abundance is the highest (post blood feeding). The asynchronous production of AMPs by both partners suggests that these antibiotic substances (i) provide them with reciprocal protection against invasive bacteria and (ii) contribute to the unusual simplicity of the gut microflora of the leech. This immune benefit substantially reinforces the evidence of an evolutionarily stable association between H. verbana and A. veronii. Altogether these data may provide insights into the processes making the association with an Aeromonas species in the digestive tract either deleterious or beneficial.

Genetic and antigenic relatedness of bovine herpesvirus-1 and pseudorabies virus

International Nuclear Information System (INIS)

Bush, C.E.

1985-01-01

The DNA sequence homology between the genomes of bovine herpesvirus-1 (BHV-1) and pseudorabies virus (PRV) was examined. Reciprocal cross hybridization of viral DNA labeled by nick translation to Southern blots of Kpnl, BamH1, EcoR1, and HindIII restriction endonuclease digested DNA, detected homologous sequences dispersed throughout the genomes of the two viruses. The DNA-DNA hybrids were found to be stable under high stringency wash conditions. Sequences of a 32 P-labeled PRV DNA A fragment probe were found to hybridize only to the BHV-1 HindIII G fragment. This indicated that the sequence homology detected between these two viruses was not simply due to fortuitous hybridization of guanine plus cytosine rich sequences. The homology between BHV-1 and PRV was determined by liquid reassociation. It was found that the hybridization rates between 32 P-labeled PRV DNA and unlabeled BHV-1 DNA and 32 P-labeled BHV-1 DNA and unlabeled PRV DNA corresponded to approximately 8% reassociation. The antigenic relatedness between BHV-1 and PRV was also examined. Eighty percent plaque reduction serum neutralization tests showed that BHV-1 rabbit hyperimmune antiserum neutralized BHV-1 virus at a serum neutralization titer (SNT) of 1:256 and PRV virus at an (SNT) of 1:8. PRV rabbit hyperimmune antiserum neutralized PRV virus at an SNT of 1:4 and BHV-1 virus at an SNT of 1:2

Genome Analysis and Phylogenetic Relatedness of Gallibacterium anatis Strains from Poultry

Science.gov (United States)

Johnson, Timothy J.; Danzeisen, Jessica L.; Trampel, Darrell; Nolan, Lisa K.; Seemann, Torsten; Bager, Ragnhild J.; Bojesen, Anders M.

2013-01-01

Peritonitis is the major disease problem of laying hens in commercial table egg and parent stock operations. Despite its importance, the etiology and pathogenesis of this disease have not been completely clarified. Although avian pathogenic Escherichia coli (APEC) isolates have been incriminated as the causative agent of laying hen peritonitis, Gallibacterium anatis are frequently isolated from peritonitis lesions. Despite recent studies suggesting a role for G. anatis in the pathogenesis of peritonitis, little is known about the organism’s virulence mechanisms, genomic composition and population dynamics. Here, we compared the genome sequences of three G. anatis isolates in an effort to understand its virulence mechanisms and identify novel antigenic traits. A multilocus sequence typing method was also established for G. anatis and used to characterize the genotypic relatedness of 71 isolates from commercial laying hens in Iowa and 18 international reference isolates. Genomic comparisons suggest that G. anatis is a highly diverse bacterial species, with some strains possessing previously described and potential virulence factors, but with a core genome containing several antigenic candidates. Multilocus sequence typing effectively distinguished 82 sequence types and several clonal complexes of G. anatis, and some clones seemed to predominate among G. anatis populations from commercial layers in Iowa. Biofilm formation and resistance to antimicrobial agents was also observed in several clades. Overall, the genomic diversity of G. anatis suggests that multiple lineages exist with differing pathogenic potential towards birds. PMID:23359626

Genome analysis and phylogenetic relatedness of Gallibacterium anatis strains from poultry.

Directory of Open Access Journals (Sweden)

Timothy J Johnson

Full Text Available Peritonitis is the major disease problem of laying hens in commercial table egg and parent stock operations. Despite its importance, the etiology and pathogenesis of this disease have not been completely clarified. Although avian pathogenic Escherichia coli (APEC isolates have been incriminated as the causative agent of laying hen peritonitis, Gallibacterium anatis are frequently isolated from peritonitis lesions. Despite recent studies suggesting a role for G. anatis in the pathogenesis of peritonitis, little is known about the organism's virulence mechanisms, genomic composition and population dynamics. Here, we compared the genome sequences of three G. anatis isolates in an effort to understand its virulence mechanisms and identify novel antigenic traits. A multilocus sequence typing method was also established for G. anatis and used to characterize the genotypic relatedness of 71 isolates from commercial laying hens in Iowa and 18 international reference isolates. Genomic comparisons suggest that G. anatis is a highly diverse bacterial species, with some strains possessing previously described and potential virulence factors, but with a core genome containing several antigenic candidates. Multilocus sequence typing effectively distinguished 82 sequence types and several clonal complexes of G. anatis, and some clones seemed to predominate among G. anatis populations from commercial layers in Iowa. Biofilm formation and resistance to antimicrobial agents was also observed in several clades. Overall, the genomic diversity of G. anatis suggests that multiple lineages exist with differing pathogenic potential towards birds.

Fungal Volatiles Can Act as Carbon Sources and Semiochemicals to Mediate Interspecific Interactions Among Bark Beetle-Associated Fungal Symbionts.

Directory of Open Access Journals (Sweden)

Jonathan A Cale

Full Text Available Mountain pine beetle (Dendroctonus ponderosae has killed millions of hectares of pine forests in western North America. Beetle success is dependent upon a community of symbiotic fungi comprised of Grosmannia clavigera, Ophiostoma montium, and Leptographium longiclavatum. Factors regulating the dynamics of this community during pine infection are largely unknown. However, fungal volatile organic compounds (FVOCs help shape fungal interactions in model and agricultural systems and thus may be important drivers of interactions among bark beetle-associated fungi. We investigated whether FVOCs can mediate interspecific interactions among mountain pine beetle's fungal symbionts by affecting fungal growth and reproduction. Headspace volatiles were collected and identified to determine species-specific volatile profiles. Interspecific effects of volatiles on fungal growth and conidia production were assessed by pairing physically-separated fungal cultures grown either on a carbon-poor or -rich substrate, inside a shared-headspace environment. Fungal VOC profiles differed by species and influenced the growth and/or conidia production of the other species. Further, our results showed that FVOCs can be used as carbon sources for fungi developing on carbon-poor substrates. This is the first report demonstrating that FVOCs can drive interactions among bark beetle fungal symbionts, and thus are important factors in beetle attack success.

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

Science.gov (United States)

Schmidt, Christiane; Morard, Raphael; Almogi-Labin, Ahuva; Weinmann, Anna E; Titelboim, Danna; Abramovich, Sigal; Kucera, Michal

2015-01-01

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

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

Directory of Open Access Journals (Sweden)

Christiane Schmidt

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

The Perceptions of Temporal Path Analysis of Learners' Self-Regulation on Learning Stress and Social Relationships in Junior High School

Science.gov (United States)

Chang, Hsiu-Ju

2016-01-01

This research focus on the temporal path analysis of learning stress, test anxiety, peer stress (classmate relatedness), teacher relatedness, autonomy, and self-regulative performance in junior high school. Owing to the processes of self-determination always combines several negotiations with the interactive perceptions of personal experiences and…

Taxonomic identity and physiological ecology of Chlamydomonas hedleyi sp. nov. , algal flagellate symbiont from the foraminifer Archaias angulatus

Energy Technology Data Exchange (ETDEWEB)

Lee, J J; Crockett, L J; Hagen, J; Stone, R J

1975-12-31

The fine structure of the symbiotic alga isolated from the foraminiferan Archaias angulatus (Fichtel et Moll) DeMontfort is typical of the Chlorophyceae of the volvocalean and chlorococcalean lines. Spherical non-motile cells, 10--14 ..mu..m in diameter, characterize the dominant life cycle phase. Long oval motile forms with truncated apices are present 3--5 days after transfer to fresh medium. The pyrenoids are embedded anteriorly in the singly bilobed chloroplast and are surrounded by a sheath of starch platelets. In spite of the non-motile state of cells in older cultures (which is perhaps a reflection of its normally symbiotic condition), the alga is identified as a species of the volvocalean genus Chlamydomonas and is named C. hedleyi sp. nov. The symbiont has no vitamin or organic requirements but growth is increased threefold in the presence of thiamine, and twofold in the presence of 1 ..mu..m glutamic acid, histidine and methionine. Urea was the best nitrogen source tested. Purines and pyrimidines did not serve as nitrogen sources. Chlamydomonas hedleyi grows well in a salinity range of 6- greater than 52 per thousand and a pH range of 6--8.5. 7.04 x 10/sup -7/ M carbon h/sup -1/ g/sup -1/ was fixed by the symbiont, 57 percent being released into the medium as a chromatographically homogeneous organic molecule provisionally identified as mannitol.

Phylogenetic relatedness predicts priority effects in nectar yeast communities

Science.gov (United States)

Peay, Kabir G.; Belisle, Melinda; Fukami, Tadashi

2012-01-01

Priority effects, in which the outcome of species interactions depends on the order of their arrival, are a key component of many models of community assembly. Yet, much remains unknown about how priority effects vary in strength among species in a community and what factors explain this variation. We experimented with a model natural community in laboratory microcosms that allowed us to quantify the strength of priority effects for most of the yeast species found in the floral nectar of a hummingbird-pollinated shrub at a biological preserve in northern California. We found that priority effects were widespread, with late-arriving species experiencing strong negative effects from early-arriving species. However, the magnitude of priority effects varied across species pairs. This variation was phylogenetically non-random, with priority effects stronger between closer relatives. Analysis of carbon and amino acid consumption profiles indicated that competition between closer relatives was more intense owing to higher ecological similarity, consistent with Darwin's naturalization hypothesis. These results suggest that phylogenetic relatedness between potential colonists may explain the strength of priority effects and, as a consequence, the degree to which community assembly is historically contingent. PMID:21775330

Short-chain alkanes fuel mussel and sponge Cycloclasticus symbionts from deep-sea gas and oil seeps.

Science.gov (United States)

Rubin-Blum, Maxim; Antony, Chakkiath Paul; Borowski, Christian; Sayavedra, Lizbeth; Pape, Thomas; Sahling, Heiko; Bohrmann, Gerhard; Kleiner, Manuel; Redmond, Molly C; Valentine, David L; Dubilier, Nicole

2017-06-19

Cycloclasticus bacteria are ubiquitous in oil-rich regions of the ocean and are known for their ability to degrade polycyclic aromatic hydrocarbons (PAHs). In this study, we describe Cycloclasticus that have established a symbiosis with Bathymodiolus heckerae mussels and poecilosclerid sponges from asphalt-rich, deep-sea oil seeps at Campeche Knolls in the southern Gulf of Mexico. Genomic and transcriptomic analyses revealed that, in contrast to all previously known Cycloclasticus, the symbiotic Cycloclasticus appears to lack the genes needed for PAH degradation. Instead, these symbionts use propane and other short-chain alkanes such as ethane and butane as carbon and energy sources, thus expanding the limited range of substrates known to power chemosynthetic symbioses. Analyses of short-chain alkanes in the environment of the Campeche Knolls symbioses revealed that these are present at high concentrations (in the μM to mM range). Comparative genomic analyses revealed high similarities between the genes used by the symbiotic Cycloclasticus to degrade short-chain alkanes and those of free-living Cycloclasticus that bloomed during the Deepwater Horizon oil spill. Our results indicate that the metabolic versatility of bacteria within the Cycloclasticus clade is higher than previously assumed, and highlight the expanded role of these keystone species in the degradation of marine hydrocarbons.

Clonal relatedness between lobular carcinoma in situ and synchronous malignant lesions

Science.gov (United States)

2012-01-01

Introduction Lobular carcinoma in situ (LCIS) has been accepted as a marker of risk for the development of invasive breast cancer, yet modern models of breast carcinogenesis include LCIS as a precursor of low-grade carcinomas. We provide evidence favoring a clonal origin for LCIS and synchronous estrogen receptor-positive malignant lesions of the ductal and lobular phenotype. Methods Patients with prior LCIS undergoing mastectomy were identified preoperatively from 2003 to 2008. Specimens were widely sampled, and frozen blocks were screened for LCIS and co-existing malignant lesions, and were subject to microdissection. Samples from 65 patients were hybridized to the Affymetrix SNP 6.0 array platform. Cases with both an LCIS sample and an associated ductal carcinoma in situ (DCIS) or invasive tumor sample were evaluated for patterns of somatic copy number changes to assess evidence of clonal relatedness. Results LCIS was identified in 44 of the cases, and among these a DCIS and/or invasive lesion was also identified in 21 cases. A total of 17 tumor pairs had adequate DNA/array data for analysis, including nine pairs of LCIS/invasive lobular cancer, four pairs of LCIS/DCIS, and four pairs of LCIS/invasive ductal cancer. Overall, seven pairs (41%) were judged to be clonally related; in five (29%) evidence suggested clonality but was equivocal, and five (29%) were considered independent. Clonal pairs were observed with all matched lesion types and low and high histological grades. We also show anecdotal evidence of clonality between a patient-matched triplet of LCIS, DCIS, and invasive ductal cancer. Conclusion Our results support the role of LCIS as a precursor in the development of both high-grade and low-grade ductal and lobular cancers. PMID:22776144

Typing and Evaluation of the Genetic Relatedness of Listeria monocytogenes Strains Isolated from Food Samples by the Multiple-Locus Variable number Tandem Repeat Analysis (MLVA

Directory of Open Access Journals (Sweden)

Behrooz Sadeghi kalani

2014-12-01

Full Text Available Background and Aim:Listeria monocytogenes cause listeriosis and fatal infections in humans. The aim of this study was typing and evaluation of the genetic relatedness of L. monocytogenes strains from food samples using MLVA technique. Materials and Methods: 317 food samples were collected from 2009 to 2013 in Tehran,Iran. After final diagnosis of L. monocytogenes DNA was extracted to perform of MLVA technique, and also PCR products were analyzed by Gene Tools software. The number of tandem repeats was determined by using special equation for each selected locus. Also typing of strains was done. Results: 24 samples of 317 food samples were positive for L. monocytogenes using standard laboratory techniques. A total 13 different types were determined by MLVA technique that type 2 and type 3 were the most abundant types by 6 and 4 strains, respectively. Conclusions: The results of this study showed the presence of L. monocytogenes in dairy products and meat samples, therefore all people, especially pregnant women should observe health tips when using these products. The results of typing showed that L. monocytogenes strains from different sources can have the same origin. MLVA technique is easy with high accuracy and this method can be used in typing and evaluation of the genetic relatedness of L. monocytogenes for determination the source of contamination.

Coral bleaching under thermal stress: putative involvement of host/symbiont recognition mechanisms.

Science.gov (United States)

Vidal-Dupiol, Jeremie; Adjeroud, Mehdi; Roger, Emmanuel; Foure, Laurent; Duval, David; Mone, Yves; Ferrier-Pages, Christine; Tambutte, Eric; Tambutte, Sylvie; Zoccola, Didier; Allemand, Denis; Mitta, Guillaume

2009-08-04

Coral bleaching can be defined as the loss of symbiotic zooxanthellae and/or their photosynthetic pigments from their cnidarian host. This major disturbance of reef ecosystems is principally induced by increases in water temperature. Since the beginning of the 1980s and the onset of global climate change, this phenomenon has been occurring at increasing rates and scales, and with increasing severity. Several studies have been undertaken in the last few years to better understand the cellular and molecular mechanisms of coral bleaching but the jigsaw puzzle is far from being complete, especially concerning the early events leading to symbiosis breakdown. The aim of the present study was to find molecular actors involved early in the mechanism leading to symbiosis collapse. In our experimental procedure, one set of Pocillopora damicornis nubbins was subjected to a gradual increase of water temperature from 28 degrees C to 32 degrees C over 15 days. A second control set kept at constant temperature (28 degrees C). The differentially expressed mRNA between the stressed states (sampled just before the onset of bleaching) and the non stressed states (control) were isolated by Suppression Subtractive Hybridization. Transcription rates of the most interesting genes (considering their putative function) were quantified by Q-RT-PCR, which revealed a significant decrease in transcription of two candidates six days before bleaching. RACE-PCR experiments showed that one of them (PdC-Lectin) contained a C-Type-Lectin domain specific for mannose. Immunolocalisation demonstrated that this host gene mediates molecular interactions between the host and the symbionts suggesting a putative role in zooxanthellae acquisition and/or sequestration. The second gene corresponds to a gene putatively involved in calcification processes (Pdcyst-rich). Its down-regulation could reflect a trade-off mechanism leading to the arrest of the mineralization process under stress. Under thermal stress

Satisfaction in terms of autonomy, competence and relatedness, and its importance in promoting job motivation in the Portuguese culture

OpenAIRE

Costa, Diogo Patricio Varandas da

2010-01-01

Degree of Master in Social and Organizational Psychology / PsycINFO Content Classification Code System: 3000 Social Psychology; 3660 Organizational Behavior Self-Determination Theory (SDT) argues that autonomy, competence and relatedness are three universally critical needs that, once satisfied, will promote self-determined types of motivation and more intrinscally motivated behaviours that yield positive effects on well-being. In contrast, researchers on cross-cultural differences argu...

A Hierarchical Multiple-Level Approach to the Assessment of Interpersonal Relatedness and Self-Definition: Implications for Research, Clinical Practice, and DSM Planning.

Science.gov (United States)

Luyten, Patrick; Blatt, Sidney J

2016-01-01

Extant research suggests there is considerable overlap between so-called 2-polarities models of personality development; that is, models that propose that personality development evolves through a dialectic synergistic interaction between 2 key developmental tasks across the life span-the development of self-definition on the one hand and of relatedness on the other. These models have attracted considerable research attention and play a central role in DSM planning. This article provides a researcher- and clinician-friendly guide to the assessment of these personality theories. We argue that current theoretical models focus on issues of relatedness and self-definition at different hierarchically organized levels of analysis; that is (a) at the level of broad personality features, (b) at the motivational level (i.e., the motivational processes underlying the development of these dimensions), and (c) at the level of underlying internal working models or cognitive affective schemas, and the specific interpersonal features and problems in which they are expressed. Implications for further research and DSM planning are outlined.

Pathways to social evolution: reciprocity, relatedness, and synergy.

Science.gov (United States)

Van Cleve, Jeremy; Akçay, Erol

2014-08-01

Many organisms live in populations structured by space and by class, exhibit plastic responses to their social partners, and are subject to nonadditive ecological and fitness effects. Social evolution theory has long recognized that all of these factors can lead to different selection pressures but has only recently attempted to synthesize how these factors interact. Using models for both discrete and continuous phenotypes, we show that analyzing these factors in a consistent framework reveals that they interact with one another in ways previously overlooked. Specifically, behavioral responses (reciprocity), genetic relatedness, and synergy interact in nontrivial ways that cannot be easily captured by simple summary indices of assortment. We demonstrate the importance of these interactions by showing how they have been neglected in previous synthetic models of social behavior both within and between species. These interactions also affect the level of behavioral responses that can evolve in the long run; proximate biological mechanisms are evolutionarily stable when they generate enough responsiveness relative to the level of responsiveness that exactly balances the ecological costs and benefits. Given the richness of social behavior across taxa, these interactions should be a boon for empirical research as they are likely crucial for describing the complex relationship linking ecology, demography, and social behavior. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

Content relatedness in the social web based on social explicit semantic analysis

Science.gov (United States)

Ntalianis, Klimis; Otterbacher, Jahna; Mastorakis, Nikolaos

2017-06-01

In this paper a novel content relatedness algorithm for social media content is proposed, based on the Explicit Semantic Analysis (ESA) technique. The proposed scheme takes into consideration social interactions. In particular starting from the vector space representation model, similarity is expressed by a summation of term weight products. In this paper, term weights are estimated by a social computing method, where the strength of each term is calculated by the attention the terms receives. For this reason each post is split into two parts, title and comments area, while attention is defined by the number of social interactions such as likes and shares. The overall approach is named Social Explicit Semantic Analysis. Experimental results on real data show the advantages and limitations of the proposed approach, while an initial comparison between ESA and S-ESA is very promising.

Synchronized sexuality of an algal symbiont and its dinoflagellate host, Peridinium balticum (Levander) Lemmermann.

Science.gov (United States)

Chesnick, J M; Cox, E R

1987-01-01

We report synchronized sexual reproduction between the chlorophyll c-containing algal endosymbiont and its dinoflagellate host in Peridinium balticum (Pyrrhophyta). This organism's importance lies in that it may represent an intermediate between primitive non-photosynthetic and advanced photosynthetic dinoflagellates. Fusion of the endosymbionts and their nuclei occurred concomitantly with syngamy of the host gametes. Significant morphological changes, including condensation of chromatin and crystalline rod formation, occurred in the symbiont nucleus during zygote development. These observations provide evidence that the endosymbiotic nucleus is not passive in sexual processes, as opposed to its reported passive state during mitosis. P. balticum may not only represent an intermediate in the evolution of chloroplast acquisition by dinoflagellates, but also, an intermediate in the evolution of the peridinian dinoflagellate sexual life history.

Sampling the light-organ microenvironment of Euprymna scolopes: description of a population of host cells in association with the bacterial symbiont Vibrio fischeri.

Science.gov (United States)

Nyholm, S V; McFall-Ngai, M J

1998-10-01

The symbiosis between the squid Euprymna scolopes and the luminous bacterium Vibrio fischeri has a pronounced diel rhythm, one component of which is the venting of the contents of the light organ into the surrounding seawater each day at dawn. In this study, we explored the use of this behavior to sample the microenvironment of the light-organ crypts. Intact crypt contents, which emerge from the lateral pores of the organ as a thick paste-like exudate, were collected from anesthetized host animals that had been exposed to a light cue. Microscopy revealed that the expelled material is composed of a conspicuous population of host cells in association with the bacterial symbionts, all of which are embedded in a dense acellular matrix that strongly resembles the bacteria-based biofilms described in other systems. Assays of the viability of expelled crypt cells revealed no dead bacterial symbionts and a mixture of live and dead host cells. Analyses of the ultrastructure, biochemistry, and phagocytic activity of a subset of the host cell population suggested that some of these cells are macrophage-like molluscan hemocytes.

Is dimethylsulfoniopropionate (DMSP) produced by the symbionts or the host in an anemone-zooxanthella symbiosis?

Science.gov (United States)

van Alstyne, K. L.; Dominique, V. J.; Muller-Parker, G.

2009-03-01

Many groups of tropical cnidarians including scleractinian corals, octocorals, corallimorphs, and anemones contain the tertiary sulfonium compound dimethylsulfoniopropionate (DMSP). It is not known if the compound is synthesized by the animals, their microalgal symbionts, or derived through their diet. We determined the source of the DMSP in several species of tropical and temperate anemones using three approaches: (1) conducting comparative measurements of DMSP in aposymbiotic and zooxanthellate anemones of three species that harbor zooxanthellae, and similar measurements in one species that can harbor both zooxanthellae and zoochlorellae, (2) manipulating the presence or absence of zooxanthellae by inoculating juvenile aposymbiotic anemones ( Aiptasia pallida) with their symbiont, Symbiodinium bermudense, and (3) manipulating the numbers of S. bermudense by growing aposymbiotic and zooxanthellate A. pallida in the light and the dark. DMSP was present in zooxanthellate anemones in concentrations of 3.4-15 μmol g-1 fresh mass (FM). In aposymbiotic Aiptasia spp. and Anthopleura elegantissima that lacked large numbers of zooxanthellae, concentrations ranged from being undetectable to 0.43 μmol g-1 FM. When aposymbiotic A. pallida were inoculated with zooxanthellae, concentrations of DMSP were an average of 4.24 μmol g-1 FM after 5 weeks; DMSP was undetectable in uninoculated control animals. Aposymbiotic anemones maintained in the light or the dark for 6 weeks contained no DMSP or zooxanthellae. Zooxanthellate anemones in the light contained five times as many zooxanthellae and approximately 7.5 times as much DMSP as zooxanthellate anemones maintained in the dark. Taken together, these data show that the zooxanthellae are the sole source of DMSP in A. pallida. The trends in DMSP concentrations in other species of zooxanthellate anemones suggest that this phenomenon is not limited to A. pallida but may be more generally true for other anemones or even other

Evidence of high inbreeding in a population of the endangered giant anteater, Myrmecophaga tridactyla (Myrmecophagidae), from Emas National Park, Brazil

OpenAIRE

Collevatti, Rosane G.; Leite, Kelly C.E.; Miranda, Guilherme H.B. de; Rodrigues, Flavio H.G.

2007-01-01

We report the genetic structure, relatedness and mating structure of a population of the endangered giant anteater Myrmecophaga tridactyla Linnaeus, 1758 in the Emas National Park, Brazil, based on variability at five microsatellite loci. Additionally, we addressed the hypothesis that the M. tridactyla population studied has low levels of polymorphism and high levels of inbreeding and relatedness and that animals with overlapping home range are highly related. All five microsatellite loci dis...

Towards a molecular understanding of symbiont function: identification of a fungal gene for the degradation of xylan in the fungus gardens of leaf-cutting ants

DEFF Research Database (Denmark)

Schiøtt, Morten; De Fine Licht, Henrik H; Lange, Lene

2008-01-01

-substrate degradation in fungus gardens is a multi-step process comparable to normal biodegradation of organic matter in soil ecosystems, but with the crucial difference that a single fungal symbiont realizes most of the steps that are normally provided by a series of microorganisms that colonize fallen leaves...

Relatedness, national boarders, perceptions of firms and the value of their innovations

Science.gov (United States)

Castor, Adam R.

The main goal of this dissertation is to better understand how external corporate stakeholder perceptions of relatedness affect important outcomes for companies. In pursuit of this goal, I apply the lens of category studies. Categories not only help audiences to distinguish between members of different categories, they also convey patterns of relatedness. In turn, this may have implications for understanding how audiences search, what they attend to, and how the members are ultimately valued. In the first chapter, I apply incites from social psychology to show how the nationality of audience members affects the way that they cognitively group objects into similar categories. I find that the geographic location of stock market analysts affect the degree to which they will revise their earnings estimates for a given company in the wake of an earnings miss by another firm in the same industry. Foreign analysts revise their earnings estimates downward more so than do local analysts, suggesting that foreign analysts ascribe the earnings miss more broadly and tend to lump companies located in the same country into larger groups than do local analysts. In the second chapter, I demonstrate that the structure of inter-category relationships can have consequential effects for the members of a focal category. Leveraging an experimental-like design, I study the outcomes of nanotechnology patents and the pattern of forward citations across multiple patent jurisdictions. I find that members of technology categories with many close category 'neighbors' are more broadly cited than members of categories with few category 'neighbors.' My findings highlight how category embeddedness and category system structure affect the outcomes of category members as well as the role that classification plays in the valuation of innovation. In the third chapter, I propose a novel and dynamic measure of corporate similarity that is constructed from the two-mode analyst and company coverage network

Understanding Freud's conflicted view of the object-relatedness of sexuality and its implications for contemporary psychoanalysis: A re-examination of Three Essays on the Theory of Sexuality.

Science.gov (United States)

Blass, Rachel B

2016-06-01

Through a re-examination of Three Essays on the Theory of Sexuality (1905), this paper reveals a fundamental tension in Freud's thinking on the nature of the individual and of his sexuality. In this text Freud portrays the individual and sexuality as inherently object-related and at the same time as inherently independent of such relatedness. The way in which Freud presents these contradictory ideas suggests that he was not merely undecided on object-relatedness and sexuality but rather that the contradiction was integral to this thinking. The paper offers an explanation of the meaning of this contradiction, of why it has been neglected in the analytic literature, and of some implications for contemporary psychoanalysis and its approach to sexuality. Copyright © 2016 Institute of Psychoanalysis.

Disentangling the Taxonomy of Rickettsiales and Description of Two Novel Symbionts ("Candidatus Bealeia paramacronuclearis" and "Candidatus Fokinia cryptica") Sharing the Cytoplasm of the Ciliate Protist Paramecium biaurelia.

Science.gov (United States)

Szokoli, Franziska; Castelli, Michele; Sabaneyeva, Elena; Schrallhammer, Martina; Krenek, Sascha; Doak, Thomas G; Berendonk, Thomas U; Petroni, Giulio

2016-12-15

In the past 10 years, the number of endosymbionts described within the bacterial order Rickettsiales has constantly grown. Since 2006, 18 novel Rickettsiales genera inhabiting protists, such as ciliates and amoebae, have been described. In this work, we characterize two novel bacterial endosymbionts from Paramecium collected near Bloomington, IN. Both endosymbiotic species inhabit the cytoplasm of the same host. The Gram-negative bacterium "Candidatus Bealeia paramacronuclearis" occurs in clumps and is frequently associated with the host macronucleus. With its electron-dense cytoplasm and a distinct halo surrounding the cell, it is easily distinguishable from the second smaller symbiont, "Candidatus Fokinia cryptica," whose cytoplasm is electron lucid, lacks a halo, and is always surrounded by a symbiontophorous vacuole. For molecular characterization, the small-subunit rRNA genes were sequenced and used for taxonomic assignment as well as the design of species-specific oligonucleotide probes. Phylogenetic analyses revealed that "Candidatus Bealeia paramacronuclearis" clusters with the so-called "basal" Rickettsiales, and "Candidatus Fokinia cryptica" belongs to "Candidatus Midichloriaceae." We obtained tree topologies showing a separation of Rickettsiales into at least two groups: one represented by the families Rickettsiaceae, Anaplasmataceae, and "Candidatus Midichloriaceae" (RAM clade), and the other represented by "basal Rickettsiales," including "Candidatus Bealeia paramacronuclearis." Therefore, and in accordance with recent publications, we propose to limit the order Rickettsiales to the RAM clade and to raise "basal Rickettsiales" to an independent order, Holosporales ord. nov., inside Alphaproteobacteria, which presently includes four family-level clades. Additionally, we define the family "Candidatus Hepatincolaceae" and redefine the family Holosporaceae IMPORTANCE: In this paper, we provide the characterization of two novel bacterial symbionts

Bacterial cell motility of Burkholderia gut symbiont is required to colonize the insect gut.

Science.gov (United States)

Lee, Jun Beom; Byeon, Jin Hee; Jang, Ho Am; Kim, Jiyeun Kate; Yoo, Jin Wook; Kikuchi, Yoshitomo; Lee, Bok Luel

2015-09-14

We generated a Burkholderia mutant, which is deficient of an N-acetylmuramyl-l-alanine amidase, AmiC, involved in peptidoglycan degradation. When non-motile ΔamiC mutant Burkholderia cells harboring chain form were orally administered to Riptortus insects, ΔamiC mutant cells were unable to establish symbiotic association. But, ΔamiC mutant complemented with amiC gene restored in vivo symbiotic association. ΔamiC mutant cultured in minimal medium restored their motility with single-celled morphology. When ΔamiC mutant cells harboring single-celled morphology were administered to the host insect, this mutant established normal symbiotic association, suggesting that bacterial motility is essential for the successful symbiosis between host insect and Burkholderia symbiont. Copyright © 2015 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

Eye-specification genes in the bacterial light organ of the bobtail squid Euprymna scolopes, and their expression in response to symbiont cues.

Science.gov (United States)

Peyer, Suzanne M; Pankey, M Sabrina; Oakley, Todd H; McFall-Ngai, Margaret J

2014-02-01

The squid Euprymna scolopes has evolved independent sets of tissues capable of light detection, including a complex eye and a photophore or 'light organ', which houses the luminous bacterial symbiont Vibrio fischeri. As the eye and light organ originate from different embryonic tissues, we examined whether the eye-specification genes, pax6, eya, six, and dac, are shared by these two organs, and if so, whether they are regulated in the light organ by symbiosis. We obtained sequences of the four genes with PCR, confirmed orthology with phylogenetic analysis, and determined that each was expressed in the eye and light organ. With in situ hybridization (ISH), we localized the gene transcripts in developing embryos, comparing the patterns of expression in the two organs. The four transcripts localized to similar tissues, including those associated with the visual system ∼1/4 into embryogenesis (Naef stage 18) and the light organ ∼3/4 into embryogenesis (Naef stage 26). We used ISH and quantitative real-time PCR to examine transcript expression and differential regulation in postembryonic light organs in response to the following colonization conditions: wild-type, luminescent V. fischeri; a mutant strain defective in light production; and as a control, no symbiont. In ISH experiments light organs showed down regulation of the pax6, eya, and six transcripts in response to wild-type V. fischeri. Mutant strains also induced down regulation of the pax6 and eya transcripts, but not of the six transcript. Thus, luminescence was required for down regulation of the six transcript. We discuss these results in the context of symbiont-induced light-organ development. Our study indicates that the eye-specification genes are expressed in light-interacting tissues independent of their embryonic origin and are capable of responding to bacterial cues. These results offer evidence for evolutionary tinkering or the recruitment of eye development genes for use in a light

Coral bleaching under thermal stress: putative involvement of host/symbiont recognition mechanisms

Directory of Open Access Journals (Sweden)

Tambutte Sylvie

2009-08-01

Full Text Available Abstract Background Coral bleaching can be defined as the loss of symbiotic zooxanthellae and/or their photosynthetic pigments from their cnidarian host. This major disturbance of reef ecosystems is principally induced by increases in water temperature. Since the beginning of the 1980s and the onset of global climate change, this phenomenon has been occurring at increasing rates and scales, and with increasing severity. Several studies have been undertaken in the last few years to better understand the cellular and molecular mechanisms of coral bleaching but the jigsaw puzzle is far from being complete, especially concerning the early events leading to symbiosis breakdown. The aim of the present study was to find molecular actors involved early in the mechanism leading to symbiosis collapse. Results In our experimental procedure, one set of Pocillopora damicornis nubbins was subjected to a gradual increase of water temperature from 28°C to 32°C over 15 days. A second control set kept at constant temperature (28°C. The differentially expressed mRNA between the stressed states (sampled just before the onset of bleaching and the non stressed states (control were isolated by Suppression Subtractive Hybridization. Transcription rates of the most interesting genes (considering their putative function were quantified by Q-RT-PCR, which revealed a significant decrease in transcription of two candidates six days before bleaching. RACE-PCR experiments showed that one of them (PdC-Lectin contained a C-Type-Lectin domain specific for mannose. Immunolocalisation demonstrated that this host gene mediates molecular interactions between the host and the symbionts suggesting a putative role in zooxanthellae acquisition and/or sequestration. The second gene corresponds to a gene putatively involved in calcification processes (Pdcyst-rich. Its down-regulation could reflect a trade-off mechanism leading to the arrest of the mineralization process under stress

Symbiont-derived beta-1,3-glucanases in a social insect: mutualism beyond nutrition

Directory of Open Access Journals (Sweden)

Rebeca B Rosengaus

2014-11-01

Full Text Available Termites have had a long co-evolutionary history with prokaryotic and eukaryotic gut microbes. Historically, the role of these anaerobic obligate symbionts has been attributed to the nutritional welfare of the host. We provide evidence that protozoa (and/or their associated bacteria colonizing the hindgut of the dampwood termite Zootermopsis angusticollis, synthesize multiple functional beta-1,3-glucanases, enzymes known for breaking down beta-1,3-glucans, the main component of fungal cell walls. These enzymes, we propose, may help in both digestion of ingested fungal hyphae and protection against invasion by fungal pathogens. This research points to an additional novel role for the mutualistic hindgut microbial consortia of termites, an association that may extend beyond ligno-cellulolytic activity and nitrogen fixation to include a reduction in the risks of mycosis at both the individual- and colony-levels while nesting in and feeding on microbial-rich decayed wood.

Origin of an alternative genetic code in the extremely small and GC-rich genome of a bacterial symbiont.

Directory of Open Access Journals (Sweden)

John P McCutcheon

2009-07-01

Full Text Available The genetic code relates nucleotide sequence to amino acid sequence and is shared across all organisms, with the rare exceptions of lineages in which one or a few codons have acquired novel assignments. Recoding of UGA from stop to tryptophan has evolved independently in certain reduced bacterial genomes, including those of the mycoplasmas and some mitochondria. Small genomes typically exhibit low guanine plus cytosine (GC content, and this bias in base composition has been proposed to drive UGA Stop to Tryptophan (Stop-->Trp recoding. Using a combination of genome sequencing and high-throughput proteomics, we show that an alpha-Proteobacterial symbiont of cicadas has the unprecedented combination of an extremely small genome (144 kb, a GC-biased base composition (58.4%, and a coding reassignment of UGA Stop-->Trp. Although it is not clear why this tiny genome lacks the low GC content typical of other small bacterial genomes, these observations support a role of genome reduction rather than base composition as a driver of codon reassignment.

Symbiodinium transcriptomes: genome insights into the dinoflagellate symbionts of reef-building corals.

KAUST Repository

Bayer, Till

2012-04-18

Dinoflagellates are unicellular algae that are ubiquitously abundant in aquatic environments. Species of the genus Symbiodinium form symbiotic relationships with reef-building corals and other marine invertebrates. Despite their ecologic importance, little is known about the genetics of dinoflagellates in general and Symbiodinium in particular. Here, we used 454 sequencing to generate transcriptome data from two Symbiodinium species from different clades (clade A and clade B). With more than 56,000 assembled sequences per species, these data represent the largest transcriptomic resource for dinoflagellates to date. Our results corroborate previous observations that dinoflagellates possess the complete nucleosome machinery. We found a complete set of core histones as well as several H3 variants and H2A.Z in one species. Furthermore, transcriptome analysis points toward a low number of transcription factors in Symbiodinium spp. that also differ in the distribution of DNA-binding domains relative to other eukaryotes. In particular the cold shock domain was predominant among transcription factors. Additionally, we found a high number of antioxidative genes in comparison to non-symbiotic but evolutionary related organisms. These findings might be of relevance in the context of the role that Symbiodinium spp. play as coral symbionts.Our data represent the most comprehensive dinoflagellate EST data set to date. This study provides a comprehensive resource to further analyze the genetic makeup, metabolic capacities, and gene repertoire of Symbiodinium and dinoflagellates. Overall, our findings indicate that Symbiodinium possesses some unique characteristics, in particular the transcriptional regulation in Symbiodinium may differ from the currently known mechanisms of eukaryotic gene regulation.

Evidence of opposing fitness effects of parental heterozygosity and relatedness in a critically endangered marine turtle?

Science.gov (United States)

Phillips, K P; Jorgensen, T H; Jolliffe, K G; Richardson, D S

2017-11-01

How individual genetic variability relates to fitness is important in understanding evolution and the processes affecting populations of conservation concern. Heterozygosity-fitness correlations (HFCs) have been widely used to study this link in wild populations, where key parameters that affect both variability and fitness, such as inbreeding, can be difficult to measure. We used estimates of parental heterozygosity and genetic similarity ('relatedness') derived from 32 microsatellite markers to explore the relationship between genetic variability and fitness in a population of the critically endangered hawksbill turtle, Eretmochelys imbricata. We found no effect of maternal MLH (multilocus heterozygosity) on clutch size or egg success rate, and no single-locus effects. However, we found effects of paternal MLH and parental relatedness on egg success rate that interacted in a way that may result in both positive and negative effects of genetic variability. Multicollinearity in these tests was within safe limits, and null simulations suggested that the effect was not an artefact of using paternal genotypes reconstructed from large samples of offspring. Our results could imply a tension between inbreeding and outbreeding depression in this system, which is biologically feasible in turtles: female-biased natal philopatry may elevate inbreeding risk and local adaptation, and both processes may be disrupted by male-biased dispersal. Although this conclusion should be treated with caution due to a lack of significant identity disequilibrium, our study shows the importance of considering both positive and negative effects when assessing how variation in genetic variability affects fitness in wild systems. © 2017 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2017 European Society For Evolutionary Biology.

Females Choose Mates Based on Genetic Relatedness in a Small Dasyurid Marsupial, the Agile Antechinus (Antechinus agilis.

Directory of Open Access Journals (Sweden)

Marissa L Parrott

Full Text Available Females in a variety of taxa mate with more than one male during a single oestrus and exhibit mate preferences for genetically compatible males, but the influence of female mate choice on siring success is not clearly understood. Whether females choose to mate with more than one male or endure forced copulations is also often unknown. Here, we examined the effects of genetic relatedness on female mate choice and siring success in a small semelparous carnivorous marsupial, the agile antechinus (Antechinus agilis, during two consecutive breeding seasons. Experimental trials were conducted in captivity over periods of 72 hours using interconnected enclosures in which female antechinus could choose to access any of four separated males, but males were only able to access females that entered their quarters. Females had access to two genetically similar and two genetically dissimilar males simultaneously and all behavioural interactions were observed and scored from continuous video recordings. Genetic similarity between mates and paternity of young was determined by microsatellite analyses. Some females chose to enter and mate with more than one male during a single oestrus period. Although females investigated all males, they spent significantly more time visiting, and mated more times with, genetically dissimilar males. Males that were genetically dissimilar to the female sired 88% of subsequent offspring. Whilst males mated readily with most females, they rejected the advances of some receptive females, indicating a previously unexpected level of male mate choice. The results show that genetic relatedness between mates has a significant influence on mate choice, breeding and siring success in the agile antechinus.

Pedigrees or markers: Which are better in estimating relatedness and inbreeding coefficient?

Science.gov (United States)

Wang, Jinliang

2016-02-01

Individual inbreeding coefficient (F) and pairwise relatedness (r) are fundamental parameters in population genetics and have important applications in diverse fields such as human medicine, forensics, plant and animal breeding, conservation and evolutionary biology. Traditionally, both parameters are calculated from pedigrees, but are now increasingly estimated from genetic marker data. Conceptually, a pedigree gives the expected F and r values, FP and rP, with the expectations being taken (hypothetically) over an infinite number of individuals with the same pedigree. In contrast, markers give the realised (actual) F and r values at the particular marker loci of the particular individuals, FM and rM. Both pedigree (FP, rP) and marker (FM, rM) estimates can be used as inferences of genomic inbreeding coefficients FG and genomic relatedness rG, which are the underlying quantities relevant to most applications (such as estimating inbreeding depression and heritability) of F and r. In the pre-genomic era, it was widely accepted that pedigrees are much better than markers in delineating FG and rG, and markers should better be used to validate, amend and construct pedigrees rather than to replace them. Is this still true in the genomic era when genome-wide dense SNPs are available? In this simulation study, I showed that genomic markers can yield much better estimates of FG and rG than pedigrees when they are numerous (say, 10(4) SNPs) under realistic situations (e.g. genome and population sizes). Pedigree estimates are especially poor for species with a small genome, where FG and rG are determined to a large extent by Mendelian segregations and may thus deviate substantially from their expectations (FP and rP). Simulations also confirmed that FM, when estimated from many SNPs, can be much more powerful than FP for detecting inbreeding depression in viability. However, I argue that pedigrees cannot be replaced completely by genomic SNPs, because the former allows for

Identification of Antipathogenic Bacterial Coral Symbionts Against Porites Ulcerative White Spots Disease

Science.gov (United States)

Sa'adah, Nor; Sabdono, Agus; Diah Permata Wijayanti, dan

2018-02-01

Coral reef ecosystems are ecosystems that are vulnerable and susceptible to damage due to the exploitation of ocean resources. One of the factors that cause coral damage is the disease that attacks the coral. Porites Ulcerative White Spots (PUWS) is a coral disease found in Indonesia and attacks the coral genera Porites allegedly caused by pathogenic microbial attacks. The purpose of this study was to identify the symbiotic bacteria on healthy coral that have antipatogenic potency against PUWS. The method used in this research was descriptive explorative. Sampling was done in Kemujan Island, Karimunjawa. Bacteria were isolated from healthy coral and coral affected by PUWS disease. Streak method was used to purify coral bacteria, while overlay and agar diffusion were used to test antipathogenic activity. Bacterial identification was carried out based on polyphasic approach. The results of this study showed that coral bacterial symbionts have antipathogenic activity against PUWS disease. The selected bacteria NM 1.2, NM 1.3 and KPSH 5. NM1.2 were closely related to Pseudoalteromonas piscicida, Pseudoalteromonas flavipulchra and Bacillus flexus, respectively.

Elevated CO{sub 2} and ozone reduce nitrogen acquisition by Pinus halepensis from its mycorrhizal symbiont

Energy Technology Data Exchange (ETDEWEB)

Kytoeviita, M.M. [Oulu Univ., Dept. of Biology, Oulu (Finland); Thiec, D. Le [Univ. Henri Poincare-Nancy, Lab. de Biologie Forestiere, Vandoeuvre-les-Nancy (France); Dizengremel, P. [Unite Ecophysiologie Forestiere-Lab. de Pollution Atmospherique, INRA-Centre de Recherches Forestieres, Champenoux (France)

2001-07-01

The effects of 700 {mu}mol mol{sup -1} CO{sub 2} and 200 nmol mol{sup -1} ozone on photosynthesis in Pinus halepensis seedlings and on N translocation from its mycorrhizal symbiont, Paxillus involutus, were studied under nutrient-poor conditions. After 79 days of exposure, ozone reduced and elevated CO{sub 2} increased net assimilation rate. However, the effect was dependent on daily accumulated exposure. No statistically significant differences in total plant mass accumulation were observed, although ozone-treated plants tended to be smaller. Changes in atmospheric gas concentrations induced changes in allocation of resources: under elevated ozone, shoots showed high priority over roots and had significantly elevated N concentrations. As a result of different shoot N concentration and net carbon assimilation rates, photosynthetic N use efficiency was significantly increased under elevated CO{sub 2} and decreased under ozone. The differences in photosynthesis were mirrored in the growth of the fungus in symbiosis with the pine seedlings. However, exposure to CO{sub 2} and ozone both reduced the symbiosis-mediated N uptake. The results suggest an increased carbon cost of symbiosis-mediated N uptake under elevated CO{sub 2} while under ozone, plant N acquisition is preferentially shifted towards increased root uptake. (au)

Breeding system and reproductive skew in a highly polygynous ant population

DEFF Research Database (Denmark)

Haag-Liautard, C.; Pedersen, Jes Søe; Ovaskainen, O.

2008-01-01

of mature queens by mark-release-recapture in 29 nests and dissected a sub-sample of queens to assess their reproductive status. We also used microsatellites to estimate relatedness within and between all classes of nestmates (queens, their mates, worker brood, queen brood and male brood). Queen number...... Factors affecting relatedness among nest members in ant colonies with high queen number are still poorly understood. In order to identify the major determinants of nest kin structure, we conducted a detailed analysis of the breeding system of the ant Formica exsecta. We estimated the number...... was very high, with an arithmetic mean of 253 per nest. Most queens (90%) were reproductively active, consistent with the genetic analyses revealing that there was only a minimal reproductive skew among nestmate queens. Despite the high queen number and low reproductive skew, almost all classes...

Interaction of arbuscular mycorrhizal symbionts with arsenic and other potentially toxic elements

International Nuclear Information System (INIS)

Khairuddin Abdul Rahim

2000-01-01

The response of arbuscular mycorrhizal (AM) symbionts to arsenic, and arsenic interactions with phosphorus and potentially toxic elements (PTEs) in soils from a former arsenic mine, the Devon Great Consols, were investigated. The objective was to determine whether AM associations ameliorate arsenic toxicity in Plantago lanceolata and Agrostis capillaris, plants commonly found at abandoned mines. An exploratory investigation indicated the richness in biodiversity of AMF that colonised plants growing at the site. Arsenic was found at high concentrations and was strongly associated with copper and iron. P. lanceolata was always colonised by AMF, while colonisation of A. capillaris was variable. There was no evidence in the field of soil pH or PTEs influencing AMF colonisation and spore density. There was no strong correlation between arsenic content in plant and available arsenic, obtained through various extraction methods. Spore germination and infectivity in the mine soils were strongly influenced by the AMF genotype and to a lesser extent by the soil environment. P. lanceolata and A. capillaris root growth was inhibited at arsenic concentrations of ≥50 μg g -1 in agar. Bioavailability experiments using mine soils and Terra-Green TM (calcined attapulgite) spiked with sodium arsenate gave no evidence that AMF-colonised plants translocated less arsenic to the shoots. Plants accumulated more arsenic in their roots than in their shoots, whether they were colonised by AMF or not. The A. capillaris genotype used in the present study translocated less of both arsenic and phosphorus to its shoots than P. lanceolata. High available phosphorus in Terra-Green TM protected plants against arsenic toxicity, at -1 As. There was evidence for inhibition by arsenic in AMF colonisation of roots. For quantifying AMF extra radical hyphae contribution to arsenic transportation from growth medium to plant using a compartmented pot system, the use of low phosphorus medium and a longer

Psycholinguistic measures for German verb pairs: Semantic transparency, semantic relatedness, verb family size, and age of reading acquisition.

Science.gov (United States)

Smolka, Eva; Eulitz, Carsten

2018-06-18

A central issue in visual and spoken word recognition is the lexical representation of complex words-in particular, whether the lexical representation of complex words depends on semantic transparency: Is a complex verb like understand lexically represented as a whole word or via its base stand, given that its meaning is not transparent from the meanings of its parts? To study this issue, a number of stimulus characteristics are of interest that are not yet available in public databases of German. This article provides semantic association ratings, lexical paraphrases, and vector-based similarity measures for German verbs, measuring (a) the semantic transparency between 1,259 complex verbs and their bases, (b) the semantic relatedness between 1,109 verb pairs with 432 different bases, and (c) the vector-based similarity measures of 846 verb pairs. Additionally, we include the verb regularity of all verbs and two counts of verb family size for 184 base verbs, as well as estimates of age of acquisition and age of reading for 200 verbs. Together with lemma and type frequencies from public lexical databases, all measures can be downloaded along with this article. Statistical analyses indicate that verb family size, morphological complexity, frequency, and verb regularity affect the semantic transparency and relatedness ratings as well as the age of acquisition estimates, indicating that these are relevant variables in psycholinguistic experiments. Although lexical paraphrases, vector-based similarity measures, and semantic association ratings may deliver complementary information, the interrater reliability of the semantic association ratings for each verb pair provides valuable information when selecting stimuli for psycholinguistic experiments.

Feeling right is feeling good: Psychological well-being and emotional fit with culture in autonomy- versus relatedness-promoting situations.

Directory of Open Access Journals (Sweden)

Jozefien eDe Leersnyder

2015-05-01

Full Text Available The current research tested the idea that it is the cultural fit of emotions, rather than certain emotions per se, that predicts psychological well-being. We reasoned that emotional fit in the domains of life that afford the realization of central cultural mandates would be particularly important to psychological well-being. We tested this hypothesis with samples from three cultural contexts that are known to differ with respect to their main cultural mandates: a European American (N = 30, a Korean (N = 80, and a Belgian sample (N = 266. Cultural fit was measured by comparing an individual’s patterns of emotions to the average cultural pattern for the same type of situation on the Emotional Patterns Questionnaire (De Leersnyder, Mesquita, & Kim, 2011. Consistent with our hypothesis, we found evidence for universality without uniformity: In each sample, psychological well-being was associated with emotional fit in the domain that was key to the cultural mandate. However, cultures varied with regard to the particular domain involved. Psychological well-being was predicted by emotional fit a in autonomy-promoting situations at work in the U.S., b in relatedness-promoting situations at home in Korea, and c in both autonomy-promoting and relatedness-promoting situations in Belgium. These findings show that the experience of culturally appropriate patterns of emotions contributes to psychological well-being. One interpretation is that experiencing appropriate emotions is itself a realization of the cultural mandates.

Feeling right is feeling good: psychological well-being and emotional fit with culture in autonomy- versus relatedness-promoting situations.

Science.gov (United States)

De Leersnyder, Jozefien; Kim, Heejung; Mesquita, Batja

2015-01-01

The current research tested the idea that it is the cultural fit of emotions, rather than certain emotions per se, that predicts psychological well-being. We reasoned that emotional fit in the domains of life that afford the realization of central cultural mandates would be particularly important to psychological well-being. We tested this hypothesis with samples from three cultural contexts that are known to differ with respect to their main cultural mandates: a European American (N = 30), a Korean (N = 80), and a Belgian sample (N = 266). Cultural fit was measured by comparing an individual's patterns of emotions to the average cultural pattern for the same type of situation on the Emotional Patterns Questionnaire (De Leersnyder et al., 2011). Consistent with our hypothesis, we found evidence for "universality without uniformity": in each sample, psychological well-being was associated with emotional fit in the domain that was key to the cultural mandate. However, cultures varied with regard to the particular domain involved. Psychological well-being was predicted by emotional fit (a) in autonomy-promoting situations at work in the U.S., (b) in relatedness-promoting situations at home in Korea, and (c) in both autonomy-promoting and relatedness-promoting situations in Belgium. These findings show that the experience of culturally appropriate patterns of emotions contributes to psychological well-being. One interpretation is that experiencing appropriate emotions is itself a realization of the cultural mandates.

Genomic prediction of complex human traits: relatedness, trait architecture and predictive meta-models

Science.gov (United States)

Spiliopoulou, Athina; Nagy, Reka; Bermingham, Mairead L.; Huffman, Jennifer E.; Hayward, Caroline; Vitart, Veronique; Rudan, Igor; Campbell, Harry; Wright, Alan F.; Wilson, James F.; Pong-Wong, Ricardo; Agakov, Felix; Navarro, Pau; Haley, Chris S.

2015-01-01

We explore the prediction of individuals' phenotypes for complex traits using genomic data. We compare several widely used prediction models, including Ridge Regression, LASSO and Elastic Nets estimated from cohort data, and polygenic risk scores constructed using published summary statistics from genome-wide association meta-analyses (GWAMA). We evaluate the interplay between relatedness, trait architecture and optimal marker density, by predicting height, body mass index (BMI) and high-density lipoprotein level (HDL) in two data cohorts, originating from Croatia and Scotland. We empirically demonstrate that dense models are better when all genetic effects are small (height and BMI) and target individuals are related to the training samples, while sparse models predict better in unrelated individuals and when some effects have moderate size (HDL). For HDL sparse models achieved good across-cohort prediction, performing similarly to the GWAMA risk score and to models trained within the same cohort, which indicates that, for predicting traits with moderately sized effects, large sample sizes and familial structure become less important, though still potentially useful. Finally, we propose a novel ensemble of whole-genome predictors with GWAMA risk scores and demonstrate that the resulting meta-model achieves higher prediction accuracy than either model on its own. We conclude that although current genomic predictors are not accurate enough for diagnostic purposes, performance can be improved without requiring access to large-scale individual-level data. Our methodologically simple meta-model is a means of performing predictive meta-analysis for optimizing genomic predictions and can be easily extended to incorporate multiple population-level summary statistics or other domain knowledge. PMID:25918167

Population structure and migration pattern of a conifer pathogen, Grosmannia clavigera, as influenced by its symbiont, the mountain pine beetle.

Science.gov (United States)

Tsui, Clement K M; Roe, Amanda D; El-Kassaby, Yousry A; Rice, Adrianne V; Alamouti, Sepideh M; Sperling, Felix A H; Cooke, Janice E K; Bohlmann, Jörg; Hamelin, Richard C

2012-01-01

We investigated the population structure of Grosmannia clavigera (Gc), a fungal symbiont of the mountain pine beetle (MPB) that plays a crucial role in the establishment and reproductive success of this pathogen. This insect-fungal complex has destroyed over 16 million ha of lodgepole pine forests in Canada, the largest MPB epidemic in recorded history. During this current epidemic, MPB has expanded its range beyond historically recorded boundaries, both northward and eastward, and has now reached the jack pine of Alberta, potentially threatening the Canadian boreal forest. To better understand the dynamics between the beetle and its fungal symbiont, we sampled 19 populations in western North America and genotyped individuals from these populations with eight microsatellite markers. The fungus displayed high haplotype diversity, with over 250 unique haplotypes observed in 335 single spore isolates. Linkage equilibria in 13 of the 19 populations suggested that the fungus reproduces sexually. Bayesian clustering and distance analyses identified four genetic clusters that corresponded to four major geographical regions, which suggested that the epidemic arose from multiple geographical sources. A genetic cluster north of the Rocky Mountains, where the MPB has recently become established, experienced a population bottleneck, probably as a result of the recent range expansion. The two genetic clusters located north and west of the Rocky Mountains contained many fungal isolates admixed from all populations, possibly due to the massive movement of MPB during the epidemic. The general agreement in north-south differentiation of MPB and G. clavigera populations points to the fungal pathogen's dependence on the movement of its insect vector. In addition, the patterns of diversity and the individual assignment tests of the fungal associate suggest that migration across the Rocky Mountains occurred via a northeastern corridor, in accordance with meteorological patterns and

Delineating the effect of semantic congruency on episodic memory: the role of integration and relatedness.

Science.gov (United States)

Bein, Oded; Livneh, Neta; Reggev, Niv; Gilead, Michael; Goshen-Gottstein, Yonatan; Maril, Anat

2015-01-01

A fundamental challenge in the study of learning and memory is to understand the role of existing knowledge in the encoding and retrieval of new episodic information. The importance of prior knowledge in memory is demonstrated in the congruency effect-the robust finding wherein participants display better memory for items that are compatible, rather than incompatible, with their pre-existing semantic knowledge. Despite its robustness, the mechanism underlying this effect is not well understood. In four studies, we provide evidence that demonstrates the privileged explanatory power of the elaboration-integration account over alternative hypotheses. Furthermore, we question the implicit assumption that the congruency effect pertains to the truthfulness/sensibility of a subject-predicate proposition, and show that congruency is a function of semantic relatedness between item and context words.

Delineating the effect of semantic congruency on episodic memory: the role of integration and relatedness.

Directory of Open Access Journals (Sweden)

Oded Bein

Full Text Available A fundamental challenge in the study of learning and memory is to understand the role of existing knowledge in the encoding and retrieval of new episodic information. The importance of prior knowledge in memory is demonstrated in the congruency effect-the robust finding wherein participants display better memory for items that are compatible, rather than incompatible, with their pre-existing semantic knowledge. Despite its robustness, the mechanism underlying this effect is not well understood. In four studies, we provide evidence that demonstrates the privileged explanatory power of the elaboration-integration account over alternative hypotheses. Furthermore, we question the implicit assumption that the congruency effect pertains to the truthfulness/sensibility of a subject-predicate proposition, and show that congruency is a function of semantic relatedness between item and context words.

Eye-specification genes in the bacterial light organ of the bobtail squid Euprymna scolopes, and their expression in response to symbiont cues

OpenAIRE

Peyer, Suzanne M.; Pankey, M. Sabrina; Oakley, Todd H.; McFall-Ngai, Margaret J.

2013-01-01

The squid Euprymna scolopes has evolved independent sets of tissues capable of light detection, including a complex eye and a photophore or ‘light organ’, which houses the luminous bacterial symbiont Vibrio fischeri. As the eye and light organ originate from different embryonic tissues, we examined whether the eye-specification genes, pax6, eya, six, and dac, are shared by these two organs, and if so, whether they are regulated in the light organ by symbiosis. We obtained sequences of the fou...

Enhancing project-oriented learning by joining communities of practice and opening spaces for relatedness

Science.gov (United States)

Pascual, R.

2010-03-01

This article describes an extension to project-oriented learning to increase social construction of knowledge and learning. The focus is on: (a) maximising opportunities for students to share their knowledge with practitioners by joining communities of practice, and (b) increasing their intrinsic motivation by creating conditions for student's relatedness. The case study considers a last year capstone course in Mechanical Engineering. The work addresses innovative practices of active learning and beyond project-oriented learning through: (a) the development of a web-based decision support system, (b) meetings between the communities of students, maintenance engineers and academics, and (c) new off-campus group instances. The author hypothesises that this multi-modal approach increases deep learning and social impact of the educational process. Surveys to the actors support a successful achievement of the educational goals. The methodology can easily be extended to further improve the learning process.

Disentangling the Taxonomy of Rickettsiales and Description of Two Novel Symbionts (“Candidatus Bealeia paramacronuclearis” and “Candidatus Fokinia cryptica”) Sharing the Cytoplasm of the Ciliate Protist Paramecium biaurelia

Science.gov (United States)

Szokoli, Franziska; Castelli, Michele; Sabaneyeva, Elena; Schrallhammer, Martina; Krenek, Sascha; Doak, Thomas G.; Berendonk, Thomas U.

2016-01-01

ABSTRACT In the past 10 years, the number of endosymbionts described within the bacterial order Rickettsiales has constantly grown. Since 2006, 18 novel Rickettsiales genera inhabiting protists, such as ciliates and amoebae, have been described. In this work, we characterize two novel bacterial endosymbionts from Paramecium collected near Bloomington, IN. Both endosymbiotic species inhabit the cytoplasm of the same host. The Gram-negative bacterium “Candidatus Bealeia paramacronuclearis” occurs in clumps and is frequently associated with the host macronucleus. With its electron-dense cytoplasm and a distinct halo surrounding the cell, it is easily distinguishable from the second smaller symbiont, “Candidatus Fokinia cryptica,” whose cytoplasm is electron lucid, lacks a halo, and is always surrounded by a symbiontophorous vacuole. For molecular characterization, the small-subunit rRNA genes were sequenced and used for taxonomic assignment as well as the design of species-specific oligonucleotide probes. Phylogenetic analyses revealed that “Candidatus Bealeia paramacronuclearis” clusters with the so-called “basal” Rickettsiales, and “Candidatus Fokinia cryptica” belongs to “Candidatus Midichloriaceae.” We obtained tree topologies showing a separation of Rickettsiales into at least two groups: one represented by the families Rickettsiaceae, Anaplasmataceae, and “Candidatus Midichloriaceae” (RAM clade), and the other represented by “basal Rickettsiales,” including “Candidatus Bealeia paramacronuclearis.” Therefore, and in accordance with recent publications, we propose to limit the order Rickettsiales to the RAM clade and to raise “basal Rickettsiales” to an independent order, Holosporales ord. nov., inside Alphaproteobacteria, which presently includes four family-level clades. Additionally, we define the family “Candidatus Hepatincolaceae” and redefine the family Holosporaceae. IMPORTANCE In this paper, we provide the

The evolution of host specialization in the vertebrate gut symbiont Lactobacillus reuteri.

Directory of Open Access Journals (Sweden)

Steven A Frese

2011-02-01

Full Text Available Recent research has provided mechanistic insight into the important contributions of the gut microbiota to vertebrate biology, but questions remain about the evolutionary processes that have shaped this symbiosis. In the present study, we showed in experiments with gnotobiotic mice that the evolution of Lactobacillus reuteri with rodents resulted in the emergence of host specialization. To identify genomic events marking adaptations to the murine host, we compared the genome of the rodent isolate L. reuteri 100-23 with that of the human isolate L. reuteri F275, and we identified hundreds of genes that were specific to each strain. In order to differentiate true host-specific genome content from strain-level differences, comparative genome hybridizations were performed to query 57 L. reuteri strains originating from six different vertebrate hosts in combination with genome sequence comparisons of nine strains encompassing five phylogenetic lineages of the species. This approach revealed that rodent strains, although showing a high degree of genomic plasticity, possessed a specific genome inventory that was rare or absent in strains from other vertebrate hosts. The distinct genome content of L. reuteri lineages reflected the niche characteristics in the gastrointestinal tracts of their respective hosts, and inactivation of seven out of eight representative rodent-specific genes in L. reuteri 100-23 resulted in impaired ecological performance in the gut of mice. The comparative genomic analyses suggested fundamentally different trends of genome evolution in rodent and human L. reuteri populations, with the former possessing a large and adaptable pan-genome while the latter being subjected to a process of reductive evolution. In conclusion, this study provided experimental evidence and a molecular basis for the evolution of host specificity in a vertebrate gut symbiont, and it identified genomic events that have shaped this process.

The evolution of host specialization in the vertebrate gut symbiont Lactobacillus reuteri.

Science.gov (United States)

Frese, Steven A; Benson, Andrew K; Tannock, Gerald W; Loach, Diane M; Kim, Jaehyoung; Zhang, Min; Oh, Phaik Lyn; Heng, Nicholas C K; Patil, Prabhu B; Juge, Nathalie; Mackenzie, Donald A; Pearson, Bruce M; Lapidus, Alla; Dalin, Eileen; Tice, Hope; Goltsman, Eugene; Land, Miriam; Hauser, Loren; Ivanova, Natalia; Kyrpides, Nikos C; Walter, Jens

2011-02-01

Recent research has provided mechanistic insight into the important contributions of the gut microbiota to vertebrate biology, but questions remain about the evolutionary processes that have shaped this symbiosis. In the present study, we showed in experiments with gnotobiotic mice that the evolution of Lactobacillus reuteri with rodents resulted in the emergence of host specialization. To identify genomic events marking adaptations to the murine host, we compared the genome of the rodent isolate L. reuteri 100-23 with that of the human isolate L. reuteri F275, and we identified hundreds of genes that were specific to each strain. In order to differentiate true host-specific genome content from strain-level differences, comparative genome hybridizations were performed to query 57 L. reuteri strains originating from six different vertebrate hosts in combination with genome sequence comparisons of nine strains encompassing five phylogenetic lineages of the species. This approach revealed that rodent strains, although showing a high degree of genomic plasticity, possessed a specific genome inventory that was rare or absent in strains from other vertebrate hosts. The distinct genome content of L. reuteri lineages reflected the niche characteristics in the gastrointestinal tracts of their respective hosts, and inactivation of seven out of eight representative rodent-specific genes in L. reuteri 100-23 resulted in impaired ecological performance in the gut of mice. The comparative genomic analyses suggested fundamentally different trends of genome evolution in rodent and human L. reuteri populations, with the former possessing a large and adaptable pan-genome while the latter being subjected to a process of reductive evolution. In conclusion, this study provided experimental evidence and a molecular basis for the evolution of host specificity in a vertebrate gut symbiont, and it identified genomic events that have shaped this process.

The Evolution of Host Specialization in the Vertebrate Gut Symbiont Lactobacillus reuteri

Energy Technology Data Exchange (ETDEWEB)

Frese, Steven A. [University of Nebraska, Lincoln; Benson, Andrew K. [University of Nebraska, Lincoln; Tannock, Gerald W. [University of Otago, Dunedin, New Zealand; Loach, Diane M. [University of Otago, Dunedin, New Zealand; Kim, Jaehyoung [University of Nebraska, Lincoln; Zhang, Min [University of Nebraska, Lincoln; Oh, Phaik Lyn [University of Nebraska, Lincoln; Heng, Nicholas C. K. [University of Otago, Dunedin, New Zealand; Patil, Prabhu [University of Nebraska, Lincoln; Juge, Nathalie [Institute of Food Research, Norwich Research Park, Norwich, United Kingdom; MacKenzie, Donald A. [Institute of Food Research, Norwich Research Park, Norwich, United Kingdom; Pearson, Bruce M. [Institute of Food Research, Norwich Research Park, Norwich, United Kingdom; Lapidus, Alla L. [U.S. Department of Energy, Joint Genome Institute; Dalin, Eileen [U.S. Department of Energy, Joint Genome Institute; Tice, Hope [U.S. Department of Energy, Joint Genome Institute; Goltsman, Eugene [U.S. Department of Energy, Joint Genome Institute; Land, Miriam L [ORNL; Hauser, Loren John [ORNL; Ivanova, N [U.S. Department of Energy, Joint Genome Institute; Kyrpides, Nikos C [U.S. Department of Energy, Joint Genome Institute; Walter, Jens [University of Nebraska, Lincoln

2011-01-01

Recent research has provided mechanistic insight into the important contributions of the gut microbiota to vertebrate biology, but questions remain about the evolutionary processes that have shaped this symbiosis. In the present study, we showed in experiments with gnotobiotic mice that the evolution of Lactobacillus reuteri with rodents resulted in the emergence of host specialization. To identify genomic events marking adaptations to the murine host, we compared the genome of the rodent isolate L. reuteri 100-23 with that of the human isolate L. reuteri F275, and we identified hundreds of genes that were specific to each strain. In order to differentiate true host-specific genome content from strain-level differences, comparative genome hybridizations were performed to query 57 L. reuteri strains originating from six different vertebrate hosts in combination with genome sequence comparisons of nine strains encompassing five phylogenetic lineages of the species. This approach revealed that rodent strains, although showing a high degree of genomic plasticity, possessed a specific genome inventory that was rare or absent in strains from other vertebrate hosts. The distinct genome content of L. reuteri lineages reflected the niche characteristics in the gastrointestinal tracts of their respective hosts, and inactivation of seven out of eight representative rodent-specific genes in L. reuteri 100-23 resulted in impaired ecological performance in the gut of mice. The comparative genomic analyses suggested fundamentally different trends of genome evolution in rodent and human L. reuteri populations, with the former possessing a large and adaptable pan-genome while the latter being subjected to a process of reductive evolution. In conclusion, this study provided experimental evidence and a molecular basis for the evolution of host specificity in a vertebrate gut symbiont, and it identified genomic events that have shaped this process.

Tsetse immune system maturation requires the presence of obligate symbionts in larvae.

Directory of Open Access Journals (Sweden)

Brian L Weiss

2011-05-01

Full Text Available Beneficial microbial symbionts serve important functions within their hosts, including dietary supplementation and maintenance of immune system homeostasis. Little is known about the mechanisms that enable these bacteria to induce specific host phenotypes during development and into adulthood. Here we used the tsetse fly, Glossina morsitans, and its obligate mutualist, Wigglesworthia glossinidia, to investigate the co-evolutionary adaptations that influence the development of host physiological processes. Wigglesworthia is maternally transmitted to tsetse's intrauterine larvae through milk gland secretions. We can produce flies that lack Wigglesworthia (Gmm(Wgm- yet retain their other symbiotic microbes. Such offspring give rise to adults that exhibit a largely normal phenotype, with the exception being that they are reproductively sterile. Our results indicate that when reared under normal environmental conditions Gmm(Wgm- adults are also immuno-compromised and highly susceptible to hemocoelic E. coli infections while age-matched wild-type individuals are refractory. Adults that lack Wigglesworthia during larval development exhibit exceptionally compromised cellular and humoral immune responses following microbial challenge, including reduced expression of genes that encode antimicrobial peptides (cecropin and attacin, hemocyte-mediated processes (thioester-containing proteins 2 and 4 and prophenoloxidase, and signal-mediating molecules (inducible nitric oxide synthase. Furthermore, Gmm(Wgm- adults harbor a reduced population of sessile and circulating hemocytes, a phenomenon that likely results from a significant decrease in larval expression of serpent and lozenge, both of which are associated with the process of early hemocyte differentiation. Our results demonstrate that Wigglesworthia must be present during the development of immature progeny in order for the immune system to function properly in adult tsetse. This phenomenon provides

Influence of cell density and phase variants of bacterial symbionts (Xenorhabdus spp.) on dauer juvenile recovery and development of biocontrol nematodes Steinernema carpocapsae and S. feltiae (Nematoda: Rhabditida).

Science.gov (United States)

Hirao, A; Ehlers, R-U

2009-08-01

The rhabditid nematodes Steinernema carpocapsae and Steinernema feltiae are used in biological control of insect pests. Mass production is done in liquid culture media pre-incubated with their bacterial symbionts Xenorhabdus nematophila and Xenorhabdus bovienii, respectively, before nematode dauer juveniles (DJs) are inoculated. As a response to food signals produced by the bacterial symbionts, the DJs exit from the developmentally arrested dauer stage (they recover development) and grow to adults, which produce DJ offspring. Variable DJ recovery after inoculation often causes process failure due to non-synchronous population development and low numbers of adult nematodes. This contribution investigated the influence of the bacterial cell density on DJ recovery and development to adults. At higher density of 10(10) bacterial cells ml(-1), a higher percentage of DJ recovery was induced, and adults occurred earlier in both Steinernema spp. than at lower density of 10(9) and 10(8) cells ml(-1). Xenorhabdus symbionts produce phase variants. Recovery in bacteria-free supernatants was lower than in supernatants containing bacterial cells for both primary and secondary phase Xenorhabdus spp. and lower in secondary than in primary phase supernatants or cell suspensions. In general, recovery was lower for Steinernema feltiae and the time at which 50% of the population had recovered after exposure to the food signal was longer (RT(50) = 17.1 h) than for Steinernema carpocapsae (RT(50) = 6.6 h). Whereas >90% S. carpocapsae DJs recovered in hemolymph serum of the lepidopteran insect Galleria mellonella, recovery of S. feltiae only reached 31%. Penetration into a host insect prior to exposure to the insect's food signal did not enhance DJ recovery. Consequences for liquid culture mass production of the nematodes and differences between species of the genera Steinernema and Heterorhabditis are discussed.

Does the Structure of Female Rhesus Macaque Coo Calls Reflect Relatedness and/or Familiarity?

Directory of Open Access Journals (Sweden)

Dana Pfefferle

Full Text Available In social animals, kin relations strongly shape the social structure of a group. In female-bonded species, maternal relatedness is likely to be mediated via familiarity, but evidence is accumulating that non-human primates are able to recognize kin that they are not familiar with and adjust their behavior accordingly. In playback experiments, female rhesus macaques showed increased interest in 'coo' calls produced by unfamiliar paternal half-sisters compared to 'coo' calls produced by unfamiliar unrelated females, suggesting that these calls should have some common structural characteristics that facilitate the discrimination of kin from non-kin. Here we analyzed 'coo' calls of 67 adult female rhesus macaques from four groups and seven matrilines living on the island of Cayo Santiago (Puerto Rico. We tested whether the call structure of closely maternal and/or paternal related females, as determined from extensive pedigree data, differed from the call structure of unrelated females, while controlling for familiarity (i.e., group-matrilineal membership and age difference of subjects. In contrast to our expectation, kinship did not predict similarities in 'coo' call structure, whereas 'coo' structure was more similar when produced by females of similar age as well as by females with higher familiarity, suggesting that experience is more decisive than genetic background. The high number of individuals in the analysis and the high accuracy of the assignment of calls to individuals render a lack of power as an unlikely explanation. Thus, based on the results of this study, kin recognition in rhesus monkeys does neither appear to be based on the assessment of self-similarity, nor on the comparison among related subjects (i.e., acoustic phenotype matching, but appears to be mediated by different or multiple cues. Furthermore, the results support the notion that frequent social interactions result in increasing acoustic similarity within largely innate

Correcting for cryptic relatedness by a regression-based genomic control method

Directory of Open Access Journals (Sweden)

Yang Yaning

2009-12-01

Full Text Available Abstract Background Genomic control (GC method is a useful tool to correct for the cryptic relatedness in population-based association studies. It was originally proposed for correcting for the variance inflation of Cochran-Armitage's additive trend test by using information from unlinked null markers, and was later generalized to be applicable to other tests with the additional requirement that the null markers are matched with the candidate marker in allele frequencies. However, matching allele frequencies limits the number of available null markers and thus limits the applicability of the GC method. On the other hand, errors in genotype/allele frequencies may cause further bias and variance inflation and thereby aggravate the effect of GC correction. Results In this paper, we propose a regression-based GC method using null markers that are not necessarily matched in allele frequencies with the candidate marker. Variation of allele frequencies of the null markers is adjusted by a regression method. Conclusion The proposed method can be readily applied to the Cochran-Armitage's trend tests other than the additive trend test, the Pearson's chi-square test and other robust efficiency tests. Simulation results show that the proposed method is effective in controlling type I error in the presence of population substructure.

The problem of sampling families rather than populations: Relatedness among individuals in samples of juvenile brown trout Salmo trutta L

DEFF Research Database (Denmark)

Hansen, Michael Møller; Eg Nielsen, Einar; Mensberg, Karen-Lise Dons

1997-01-01

In species exhibiting a nonrandom distribution of closely related individuals, sampling of a few families may lead to biased estimates of allele frequencies in populations. This problem was studied in two brown trout populations, based on analysis of mtDNA and microsatellites. In both samples mt......DNA haplotype frequencies differed significantly between age classes, and in one sample 17 out of 18 individuals less than 1 year of age shared one particular mtDNA haplotype. Estimates of relatedness showed that these individuals most likely represented only three full-sib families. Older trout exhibiting...

Combined thermal and herbicide stress in functionally diverse coral symbionts

International Nuclear Information System (INIS)

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

2015-01-01

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

C5 glycolipids of heterocystous cyanobacteria track symbiont abundance in the diatom Hemiaulus hauckii across the tropical North Atlantic

Science.gov (United States)

Bale, Nicole J.; Villareal, Tracy A.; Hopmans, Ellen C.; Brussaard, Corina P. D.; Besseling, Marc; Dorhout, Denise; Sinninghe Damsté, Jaap S.; Schouten, Stefan

2018-03-01

Diatom-diazotroph associations (DDAs) include marine heterocystous cyanobacteria found as exosymbionts and endosymbionts in multiple diatom species. Heterocysts are the site of N2 fixation and have thickened cell walls containing unique heterocyst glycolipids which maintain a low oxygen environment within the heterocyst. The endosymbiotic cyanobacterium Richelia intracellularis found in species of the diatom genus Hemiaulus and Rhizosolenia makes heterocyst glycolipids (HGs) which are composed of C30 and C32 diols and triols with pentose (C5) moieties that are distinct from limnetic cyanobacterial HGs with predominantly hexose (C6) moieties. Here we applied a method for analysis of intact polar lipids to the study of HGs in suspended particulate matter (SPM) and surface sediment from across the tropical North Atlantic. The study focused on the Amazon plume region, where DDAs are documented to form extensive surface blooms, in order to examine the utility of C5 HGs as markers for DDAs as well as their transportation to underlying sediments. C30 and C32 triols with C5 pentose moieties were detected in both marine SPM and surface sediments. We found a significant correlation between the water column concentration of these long-chain C5 HGs and DDA symbiont counts. In particular, the concentrations of both the C5 HGs (1-(O-ribose)-3,27,29-triacontanetriol (C5 HG30 triol) and 1-(O-ribose)-3,29,31-dotriacontanetriol (C5 HG32 triol)) in SPM exhibited a significant correlation with the number of Hemiaulus hauckii symbionts. This result strengthens the idea that long-chain C5 HGs can be applied as biomarkers for marine endosymbiotic heterocystous cyanobacteria. The presence of the same C5 HGs in surface sediment provides evidence that they are effectively transported to the sediment and hence have potential as biomarkers for studies of the contribution of DDAs to the paleo-marine N cycle.

Genetic Relatedness Among Shiga Toxin-Producing Escherichia coli Isolated Along the Animal Food Supply Chain and in Gastroenteritis Cases in Qatar Using Multilocus Sequence Typing.

Science.gov (United States)

Palanisamy, Srikanth; Chang, YuChen; Scaria, Joy; Penha Filho, Rafael Antonio Casarin; Peters, Kenlyn E; Doiphode, Sanjay H; Sultan, Ali; Mohammed, Hussni O

2017-06-01

Pathogenic Escherichia coli has been listed among the most important bacteria associated with foodborne illnesses around the world. We investigated the genetic relatedness among Shiga toxin-producing E. coli (STEC) isolated along the animal food supply chain and from humans diagnosed with gastroenteritis in Qatar. Samples were collected from different sources along the food supply chain and from patients admitted to the hospital with complaints of gastroenteritis. All samples were screened for the presence of E. coli O157:H7 and non-O157 STEC using a combination of bacterial enrichment and molecular detection techniques. A proportional sampling approach was used to select positive samples from each source for further multilocus sequence typing (MLST) analysis. Seven housekeeping genes described for STEC were amplified by polymerase chain reaction, sequenced, and analyzed by MLST. Isolates were characterized by allele composition, sequence type (ST) and assessed for epidemiologic relationship within and among different sources. Nei's genetic distance was calculated at the allele level between sample pools in each site downstream. E. coli O157:H7 occurred at a higher rate in slaughterhouse and retail samples than at the farm or in humans in our sampling. The ST171, an ST common to enterotoxigenic E. coli and atypical enteropathogenic E. coli, was the most common ST (15%) in the food supply chain. None of the genetic distances among the different sources was statistically significant. Enterohemorrhagic E. coli pathogenic strains are present along the supply chain at different levels and with varying relatedness. Clinical isolates were the most diverse, as expected, considering the polyclonal diversity in the human microbiota. The high occurrence of these food adulterants among the farm products suggests that implementation of sanitary measures at that level might reduce the risk of human exposure.

An RT distribution analysis of relatedness proportion effects in lexical decision and semantic categorization reveals different mechanisms.

Science.gov (United States)

de Wit, Bianca; Kinoshita, Sachiko

2015-01-01

The magnitude of the semantic priming effect is known to increase as the proportion of related prime-target pairs in an experiment increases. This relatedness proportion (RP) effect was studied in a lexical decision task at a short prime-target stimulus onset asynchrony (240 ms), which is widely assumed to preclude strategic prospective usage of the prime. The analysis of the reaction time (RT) distribution suggested that the observed RP effect reflected a modulation of a retrospective semantic matching process. The pattern of the RP effect on the RT distribution found here is contrasted to that reported in De Wit and Kinoshita's (2014) semantic categorization study, and it is concluded that the RP effect is driven by different underlying mechanisms in lexical decision and semantic categorization.

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

KAUST Repository

Ziegler, Maren

2015-02-06

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

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

KAUST Repository

Ziegler, Maren; Roder, Cornelia; Bü chel, Claudia; Voolstra, Christian R.

2015-01-01

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

Deep sequencing reveals exceptional diversity and modes of transmission for bacterial sponge symbionts.

Science.gov (United States)

Webster, Nicole S; Taylor, Michael W; Behnam, Faris; Lücker, Sebastian; Rattei, Thomas; Whalan, Stephen; Horn, Matthias; Wagner, Michael

2010-08-01

Marine sponges contain complex bacterial communities of considerable ecological and biotechnological importance, with many of these organisms postulated to be specific to sponge hosts. Testing this hypothesis in light of the recent discovery of the rare microbial biosphere, we investigated three Australian sponges by massively parallel 16S rRNA gene tag pyrosequencing. Here we show bacterial diversity that is unparalleled in an invertebrate host, with more than 250,000 sponge-derived sequence tags being assigned to 23 bacterial phyla and revealing up to 2996 operational taxonomic units (95% sequence similarity) per sponge species. Of the 33 previously described 'sponge-specific' clusters that were detected in this study, 48% were found exclusively in adults and larvae - implying vertical transmission of these groups. The remaining taxa, including 'Poribacteria', were also found at very low abundance among the 135,000 tags retrieved from surrounding seawater. Thus, members of the rare seawater biosphere may serve as seed organisms for widely occurring symbiont populations in sponges and their host association might have evolved much more recently than previously thought. © 2009 Society for Applied Microbiology and Blackwell Publishing Ltd.

Bacterial symbionts, Buchnera, and starvation on wing dimorphism in English grain aphid, Sitobion avenae (F. (Homoptera: Aphididae

Directory of Open Access Journals (Sweden)

Fangmei eZhang

2015-05-01

Full Text Available Wing dimorphism in aphids can be affected by multiple cues, including both biotic (nutrition, crowding, interspecific interactions, the presence of natural enemies, maternal and transgenerational effects, and alarm pheromone and abiotic factors (temperature, humidity, and photoperiod. The majority of the phloem-feeding aphids carry Buchnera, an obligate symbiotic proteobacteria. Buchnera has a highly reduced genome size, but encode key enzymes in the tryptophan biosynthetic pathway and is crucial for nutritional balance, development and reproduction in aphids. In this study, we investigated the impact of two nutritional-based biotic factors, symbionts and starvation, on the wing dimorphism in the English grain aphid, Sitobion avenae, a devastating insect pest of cereal crops (e.g., wheat worldwide. Elimination of Buchnera using the antibiotic rifampicin significantly reduced the formation of winged morphs, body mass and fecundity in S. avenae. Furthermore, the absence of this primary endosymbiont may disrupt the nutrient acquisition in aphids and alter transgenerational phenotypic expression. Similarly, both survival rate and the formation of winged morphs were substantially reduced after neonatal (< 24h old offspring were starved for a period of time. The combined results shed light on the impact of two nutritional-based biotic factors on the phenotypic plasticity in aphids. A better understanding of the wing dimorphism in aphids will provide the theoretical basis for the prediction and integrated management of these phloem-feeding insect pests.

The emergence of new technology-based industries: the case of fuel cells and its technological relatedness to regional knowledge bases

DEFF Research Database (Denmark)

Tanner, Anne Nygaard

2016-01-01

to emerging radical technologies that create the foundation for new industries. The article develops a new measure for technological relatedness between the knowledge base of a region and that of a radical technology based on patent classes. It demonstrates that emerging fuel cell technology develops where...... the regional knowledge base is technologically related to that of fuel cells and consequently confirms the evolutionary thesis.......Evolutionary economic geographers propose that regional diversification is a path-dependent process whereby industries grow out of pre-existing industrial structures through technologically related localised knowledge spillovers and learning. This article examines whether this also applies...

Genetic diversity and relatedness among seven red deer (Cervus elaphus populations

Directory of Open Access Journals (Sweden)

Lenka Maršálková

2014-02-01

Full Text Available Deer (Cervidae recently belongs to the most important species. The aim of presenting study was evaluation of genetic diversity and relationship within and among seven red deer populations from different origins - Czech Republic, Hungary, hybrids Hungary x New Zealand, Lithuania, New Zealand, Poland and Slovak Republic. This study was conducted to determine the levels of genetic variability and relationships among deer populations from a total of 637 animals originating from seven countries Czech Republic (50, Hungary (35, Hungary x New Zealand hybrids (67, Lithuania (26, New Zealand (82, Poland (347 and Slovak Republic (30.  We used the hair bulbs as a source of DNA.  In total, 213 alleles were observed from the 10 loci surveyed. The number of alleles per locus ranged from 11 (IOBT965 to 35 (T156, RT13. Genetic diversity and relatedness among red deer populations has been performed on a total of 637 animals. A panel of 10 microsatellite markers used in deer were optimized. On the basis of this panel of microsatellites we were investigated genetic variability and relationships by using statistical and graphical programmes. We evaluated how close populations are to each other and their genetic admixture. Molecular genetic data combined with evaluation in statistical programmes could lead to a complex view of populations. 

Sex allocation in fungus-growing ants: worker or queen control without symbiont-induced female bias

DEFF Research Database (Denmark)

Dijkstra, Michiel B.; Boomsma, Jacobus Jan

2008-01-01

The fungal cultivars of fungus-growing ants are vertically transmitted by queens but not males. Selection would therefore favor cultivars that bias the ants' sex ratio towards gynes, beyond the gyne bias that is optimal for workers and queens. We measured sex allocation in 190 colonies of six...... sympatric fungus-growing ant species. As predicted from relatedness, female bias was greater in four singly mated Sericomyrmex and Trachymyrmex species than in two multiply mated Acromyrmex species. Colonies tended to raise mainly a single sex, which could be partly explained by variation in queen number......, colony fecundity, and fungal garden volume for Acromyrmex and Sericomyrmex, but not for Trachymyrmex. Year of collection, worker number and mating frequency of Acromyrmex queens did not affect the colony sex ratios. We used a novel sensitivity analysis to compare the population sex allocation ratios...

Improving the Accuracy of Attribute Extraction using the Relatedness between Attribute Values

Science.gov (United States)

Bollegala, Danushka; Tani, Naoki; Ishizuka, Mitsuru

Extracting attribute-values related to entities from web texts is an important step in numerous web related tasks such as information retrieval, information extraction, and entity disambiguation (namesake disambiguation). For example, for a search query that contains a personal name, we can not only return documents that contain that personal name, but if we have attribute-values such as the organization for which that person works, we can also suggest documents that contain information related to that organization, thereby improving the user's search experience. Despite numerous potential applications of attribute extraction, it remains a challenging task due to the inherent noise in web data -- often a single web page contains multiple entities and attributes. We propose a graph-based approach to select the correct attribute-values from a set of candidate attribute-values extracted for a particular entity. First, we build an undirected weighted graph in which, attribute-values are represented by nodes, and the edge that connects two nodes in the graph represents the degree of relatedness between the corresponding attribute-values. Next, we find the maximum spanning tree of this graph that connects exactly one attribute-value for each attribute-type. The proposed method outperforms previously proposed attribute extraction methods on a dataset that contains 5000 web pages.

Impact of Semantic Relatedness on Associative Memory: An ERP Study

Directory of Open Access Journals (Sweden)

Pierre Desaunay

2017-06-01

Full Text Available Encoding and retrieval processes in memory for pairs of pictures are thought to be influenced by inter-item similarity and by features of individual items. Using Event-Related Potentials (ERP, we aimed to identify how these processes impact on both the early mid-frontal FN400 and the Late Positive Component (LPC potentials during associative retrieval of pictures. Twenty young adults undertook a sham task, using an incidental encoding of semantically related and unrelated pairs of drawings. At test, we conducted a recognition task in which participants were asked to identify target identical pairs of pictures, which could be semantically related or unrelated, among new and rearranged pairs. We observed semantic (related and unrelated pairs and condition effects (old, rearranged and new pairs on the early mid-frontal potential. First, a lower amplitude was shown for identical and rearranged semantically related pairs, which might reflect a retrieval process driven by semantic cues. Second, among semantically unrelated pairs, we found a larger negativity for identical pairs, compared to rearranged and new ones, suggesting additional retrieval processing that focuses on associative information. We also observed an LPC old/new effect with a mid-parietal and a right occipito-parietal topography for semantically related and unrelated old pairs, demonstrating a recollection phenomenon irrespective of the degree of association. These findings suggest that associative recognition using visual stimuli begins at early stages of retrieval, and differs according to the degree of semantic relatedness among items. However, either strategy may ultimately lead to recollection processes.

Revised systematics of Holospora-like bacteria and characterization of "Candidatus Gortzia infectiva", a novel macronuclear symbiont of Paramecium jenningsi.

Science.gov (United States)

Boscaro, Vittorio; Fokin, Sergei I; Schrallhammer, Martina; Schweikert, Michael; Petroni, Giulio

2013-01-01

The genus Holospora (Rickettsiales) includes highly infectious nuclear symbionts of the ciliate Paramecium with unique morphology and life cycle. To date, nine species have been described, but a molecular characterization is lacking for most of them. In this study, we have characterized a novel Holospora-like bacterium (HLB) living in the macronuclei of a Paramecium jenningsi population. This bacterium was morphologically and ultrastructurally investigated in detail, and its life cycle and infection capabilities were described. We also obtained its 16S rRNA gene sequence and developed a specific probe for fluorescence in situ hybridization experiments. A new taxon, "Candidatus Gortzia infectiva", was established for this HLB according to its unique characteristics and the relatively low DNA sequence similarities shared with other bacteria. The phylogeny of the order Rickettsiales based on 16S rRNA gene sequences has been inferred, adding to the available data the sequence of the novel bacterium and those of two Holospora species (Holospora obtusa and Holospora undulata) characterized for the purpose. Our phylogenetic analysis provided molecular support for the monophyly of HLBs and showed a possible pattern of evolution for some of their features. We suggested to classify inside the family Holosporaceae only HLBs, excluding other more distantly related and phenotypically different Paramecium endosymbionts.

The Plasmid Mobilome of the Model Plant-Symbiont Sinorhizobium meliloti: Coming up with New Questions and Answers.

Science.gov (United States)

Lagares, Antonio; Sanjuán, Juan; Pistorio, Mariano

2014-10-01

Rhizobia are Gram-negative Alpha- and Betaproteobacteria living in the underground which have the ability to associate with legumes for the establishment of nitrogen-fixing symbioses. Sinorhizobium meliloti in particular-the symbiont of Medicago, Melilotus, and Trigonella spp.-has for the past decades served as a model organism for investigating, at the molecular level, the biology, biochemistry, and genetics of a free-living and symbiotic soil bacterium of agricultural relevance. To date, the genomes of seven different S. meliloti strains have been fully sequenced and annotated, and several other draft genomic sequences are also available. The vast amount of plasmid DNA that S. meliloti frequently bears (up to 45% of its total genome), the conjugative ability of some of those plasmids, and the extent of the plasmid diversity has provided researchers with an extraordinary system to investigate functional and structural plasmid molecular biology within the evolutionary context surrounding a plant-associated model bacterium. Current evidence indicates that the plasmid mobilome in S. meliloti is composed of replicons varying greatly in size and having diverse conjugative systems and properties along with different evolutionary stabilities and biological roles. While plasmids carrying symbiotic functions (pSyms) are known to have high structural stability (approaching that of chromosomes), the remaining plasmid mobilome (referred to as the non-pSym, functionally cryptic, or accessory compartment) has been shown to possess remarkable diversity and to be highly active in conjugation. In light of the modern genomic and current biochemical data on the plasmids of S. meliloti, the current article revises their main structural components, their transfer and regulatory mechanisms, and their potential as vehicles in shaping the evolution of the rhizobial genome.

Luciferase genes cloned from the unculturable luminous bacteroid symbiont of the Caribbean flashlight fish, Kryptophanaron alfredi.

Science.gov (United States)

Haygood, M G; Cohn, D H

1986-01-01

Light organs of anomalopid (flashlight) fish contain luminous bacteroids that have never been cultured and, consequently, have been difficult to study. We have characterized the luciferase (lux) region of DNA extracted from light organs of the Caribbean flashlight fish Kryptophanaron alfredi by hybridization of cloned Vibrio harveyi lux genes to restriction-endonuclease-digested, light organ DNA. Comparison of the hybridization pattern of light organ DNA with that of DNA of a putative symbiotic isolate provides a method for identifying the authentic luminous symbiont regardless of its luminescence, and was used to reject one such isolate. Light organ DNA was further used to construct a cosmid clone bank and the luciferase genes were isolated. Unlike other bacterial luciferase genes, the genes were not expressed in Escherichia coli. When placed under the control of the E. coli trp promoter, the genes were transcribed but no luciferase was detected, suggesting a posttranscriptional block to expression.

Cutinase of Fusarium solani F. sp. pisi: mechanism of induction and relatedness to other Fusarium species

International Nuclear Information System (INIS)

Woloshuk, C.P.

1986-01-01

Three studies were made on the extracellular cutinase of the phytopathogenic fungus Fusarium solani f. sp. pisi. I. The production of cutinase was found to be induced in spores of F. solani f. sp. pisi, strain T-8, by cutin and cutin hydrolysate. Fractionation and analysis of the cutin hydrolysate indicated that dihydroxy-C 16 acid and trihydroxy-C 18 acid were the cutin monomers most active for inducing cutinase. Measurement of cutinase-specific RNA levels by dot-blot hybridization with a [ 32 P]-labeled cutinase cDNA showed that the cutinase gene transcripts could be detected within 15 min after addition of the inducers. The results indicated that the fungal spores have the capacity to recognize the unique monomer components of the plant cuticle and rapidly respond by the synthesis of cutinase. II. Analysis of the genomic DNA's of seven strains of F. solani f. sp. pisi indicated that both high and low cutinase-producing strains contain at least one copy of the cutinase structural gene and a homologous promoter region. The data suggest a different promoter sequence exists in these additional copies. III. Relatedness of five phytopathogenic Fusarium species to F. solani f. sp. pisi was determined by their cutinase antigenic properties and gene homologies of cutinase cDNA from F. solani f. sp. pisi. The results suggest that formae specialis of F. solani are phylogenetically identical and that F. solani is quite distinct from the other Fusarium species tested

Genetic relatedness and molecular characterization of multidrug resistant Acinetobacter baumannii isolated in central Ohio, USA

Directory of Open Access Journals (Sweden)

Tadesse Daniel

2009-06-01

Full Text Available Abstract Background Over the last decade, nosocomial infections due to Acinetobacter baumannii have been described with an increasing trend towards multidrug resistance, mostly in intensive care units. The aim of the present study was to determine the clonal relatedness of clinical isolates and to elucidate the genetic basis of imipenem resistance. Methods A. baumannii isolates (n = 83 originated from two hospital settings in central Ohio were used in this study. Pulsed-field gel electrophoresis genotyping and antimicrobial susceptibility testing for clinically relevant antimicrobials were performed. Resistance determinants were characterized by using different phenotypic (accumulation assay for efflux and genotypic (PCR, DNA sequencing, plasmid analysis and electroporation approaches. Results The isolates were predominantly multidrug resistant (>79.5% and comprised of thirteen unique pulsotypes, with genotype VII circulating in both hospitals. The presence of blaOXA-23 in 13% (11/83 and ISAba1 linked blaOXA-66 in 79.5% (66/83 of clinical isolates was associated with high level imipenem resistance. In this set of OXA producing isolates, multidrug resistance was bestowed by blaADC-25, class 1 integron-borne aminoglycoside modifying enzymes, presence of sense mutations in gyrA/parC and involvement of active efflux (with evidence for the presence of adeB efflux gene. Conclusion This study underscores the major role of carbapenem-hydrolyzing class D β-lactamases, and in particular the acquired OXA-23, in the dissemination of imipenem-resistant A. baumannii. The co-occurrence of additional resistance determinant could also be a significant threat.