Symbiosis

Association of young Chloroscombrus chrysurus (Pisces: Carangidae) with the jellyfish Aurelia aurita

by Greg Tolley

Transport of symbiotic zooxanthellae in mesogleal canals of Zoanthus robustus?

by Rosanne Quinnell

Rodriguez-Lanetty, M., C. Scaramuzzi, R. G. Quinnell and A. W. D. Larkum, 2005. Coral Reefs Volume 24, Number 2: 195 - 196
DOI: 10.1007/s00338-004-0457-z

Mutualism variation in the nodulation response to nitrate

by Amanda Stock

Introducing Universal Symbiogenesis

by Nathalie Gontier

In: O. Pombo et al. (eds.), Special Sciences and the Unity of Science. Series: Logic, Epistemology, and the Unity of Science 24. Dordrecht Springer.
DOI 10.1007/978-94-007-2030-5 6,

Carbon availability triggers fungal nitrogen uptake and transport in arbuscular mycorrhizal symbiosis

by Gary Strahan

Carl R. Fellbaum, Emma W. Gachomo, Yugandhar Beesetty, Sulbha Choudhari, Gary D. Strahan, Philip E. Pfeffer, E. Toby Kiers and
Heike Bücking

Proceedings of the National Academy of Sciences of the United States of America. 02/2012; 109(7):2666-71.

Published online before print January 30, 2012

The arbuscular mycorrhizal (AM) symbiosis, formed between the majority of land plants and ubiquitous soil fungi of the... more The arbuscular mycorrhizal (AM) symbiosis, formed between the majority of land plants and ubiquitous soil fungi of the phylum Glomeromycota, is responsible for massive nutrient transfer and global carbon sequestration....

Biased oviposition and biased survival together help resolve a fig-wasp conflict

by Douglas Yu

Hui Wang, Jo Ridley, Derek W. Dunn, Ruiwu Wang, James M. Cook, Douglas W. Yu. Manuscript

We report evidence that helps to resolve competing explanations for stability in the classic fig-wasp mutualism. Fig... more We report evidence that helps to resolve competing explanations for stability in the classic fig-wasp mutualism. Fig trees are pollinated by wasps that lay their eggs in the tree’s ovules. Each wasp larva then develops at the expense of a fig seed. Upon maturity, the female wasps collect pollen and disperse to a new tree, continuing the cycle. Fig fitness is increased by producing both seeds and wasps, whereas short-term wasp fitness increases only with more wasps, thereby leading to a conflict of interests. We show experimentally that wasps exploit the inner layers of ovules first (biased oviposition), which is consistent with optimal-foraging theory. As oviposition increases, seeds in the middle layer are replaced on a one-to-one basis by pollinator offspring. Finally, in the outer layer of ovules, seeds disappear but are only partially replaced by pollinator offspring, which suggests high wasp mortality, perhaps due to plant defences (biased survival). We propose that selection to increase growth rate in inner ovules trades off against survivorship in outer ovules, and since there are more wasp offspring in inner ovules, biased survival is maintained. Our results suggest that both biased oviposition and biased survivorship ensure seed production in figs, thereby stabilising the mutualism. Finally, we report evidence suggesting that fig trees direct more resources to figs with more seeds, and this may help balance seed and wasp production at the level of the tree. Because an equal allocation would appear to favour the fig’s interests, the fig appears to be in control of the mutualism.

How to assemble a beneficial microbiome in three easy steps

by Douglas Yu

Istvan Scheuring and Douglas W. Yu. Manuscript.

There is great interest in explaining how beneficial microbiomes are assembled. An exemplar is the attine ants, which... more There is great interest in explaining how beneficial microbiomes are assembled. An exemplar is the attine ants, which cultivate a fungal garden for food and also host a cuticular microbiome that releases antibiotics to defend the garden from parasites. One explanation posits long-term vertical transmission of Pseudonocardia bacteria, which (somehow) continuously evolve compounds in arms-race fashion against parasites. Alternatively, attines are argued to selectively take up (somehow) multiple, non-coevolved actinobacterial genera from the soil, enabling a multi-drug strategy against parasites. We reconcile these two explanations by showing that when hosts provide high resource levels, interference competition is fuelled, and the recruitment of antibiotic-producing (and resistant) bacteria is thereby favored. This partner-choice mechanism is more likely to work if at least one actinobacterial symbiont is vertically transmitted or has a high immigration rate, providing a key role for Pseudonocardia in the attine symbiosis. Our model can also apply to the very wide range of hosts that house antibiotic-producing microbes, including vertebrates, mollusks, arthropods, corals, and plant rhizospheres.

Modelling the evolution of mutualistic symbioses

by Emily Jones

Friesen, M. L., and E. I. Jones. 2012. In J. van Helden, A. Toussaint, and D. Thieffry, eds. Bacterial Molecular Networks. Methods in Molecular Biology, Springer New York, 804: 481-499.

Mutualistic microbial symbioses are one of the key innovations in the evolution of biological diversity, enabling the... more Mutualistic microbial symbioses are one of the key innovations in the evolution of biological diversity, enabling the expansion of species’ niches and the production of sophisticated structures such as the eukaryotic cell. For some of the best-studied cases, we are beginning to have network models of symbiotic metabolism, but this work is in its infancy and has not been developed with an evolutionary perspective. However, theoreticians have long been interested in how these symbioses arise and persist and have applied modelling approaches from economics, evolution, ecology, and sociobology to a number of fundamental questions. We provide an overview of these questions, followed by specific modelling examples. We cover economic game theory, including the Prisoner’s Dilemma, the Snowdrift game, and biological markets. We also describe the eco-evolutionary framework of adaptive dynamics, inclusive fitness, and population genetic models. We aim to provide insight into the strengths and weaknesses of each approach and into how current evolutionary methods can benefit an understanding of the mechanistic basis of host–symbiont interactions elucidated by molecular network models.

Baeza, J.A. The symbiotic lifestyle and its evolutionary consequences: social monogamy and sex allocation in the hermaphroditic shrimp Lysmata pederseni. Naturwissenshaften 97: 729–741.

by Antonio Baeza

Baeza, J.A. and C. Piantoni. 2010. Sexual system, sex ratio and group living in the shrimp Thor amboinensis (De Man): relevance to resource-monopolization and sex-allocation theories. Biological Bulletin 219: 151–165.

by Antonio Baeza

Baeza, J.A. and M. Díaz-Valdés. 2011. The symbiotic shrimp Ascidonia flavomaculata lives solitarily in the tunicate Ascidia mentula; implications for its mating system. Invertebrate Biology 130(4):351–361.

by Antonio Baeza

Lynn Margulis, Symbiosis, Ethics

by Tim Morton

Published in Symbiosis, Living Books about Life (Open Humanities Press, 2011).

The fact of symbiosis demands a special attentiveness to ethics, since self-interest theories are in trouble. The fact of symbiosis demands a special attentiveness to ethics, since self-interest theories are in trouble.

Sedimentary nitrogen uptake and assimilation in the temperate zooxanthellate sea anemone Anthopleura aureoradiata

by Shaun Wilkinson

The sea anemone Anthopleura aureoradiata (Carlgren), which harbours symbiotic dinoflagellates (zooxan- thellae), is... more The sea anemone Anthopleura aureoradiata (Carlgren), which harbours symbiotic dinoflagellates (zooxan- thellae), is abundant on mudflats and rocky shores around New Zealand. We measured the potential for particulate nitrogen uptake from sediment by A. aureoradiata and the subsequent consequences of this uptake on the nitrogen status of its zooxanthellae. Sediment was rinsed, labelled with (15NH4)2SO4, and provided to anemones at low (0.23 gml−1) and high (1.33 gml−1) sediment loads for 6 h. Both anemone tissues and zooxanthellae became enriched with 15N. Enrichment of anemone tissues was similar at both high and low sediment loads, but the zooxanthellae became more enriched at the lower load. This was presumably because the uptake of ammonium, arising from host catabolism, by zooxanthellae is light driven and because the anemones at the lower load were able to extend their tentacles into the light while those at the higher load were not. The influence of sediment uptake on the nitrogen status of the zooxanthellae was determined by measuring the extent to which 20 μMNH4
seen in filtered seawater (FSW) alone; the ammonium enhancement ratio (AER) was expressed as [dark NH4
rate/dark FSW rate], where ‘rate’ refers to C fixation and a ratio of 1.0 or less indicates nitrogen sufficiency. When anemones were starved with and without rinsed sediment in nitrogen-free artificial seawater for 8 weeks, zooxanthellar nitrogen deficiency became apparent at 2–4 weeks and reached similar levels in both treatments (AER=~2). In contrast, anemones fed 5 times per week for 8 weeks with Artemia nauplii were nitrogen sufficient (AER=1.03). In the field, zooxanthellae from mudflat anemones were largely nitrogen sufficient (AER=1.26), while nitrogen deficient zooxanthellae were present in anemones from a rocky intertidal site (AER=2.93). These results suggest that, while there was evidence for particulate nitrogen uptake, dissolved inorganic nitrogen (especially ammonium) in interstitial pore water may be a more important source of nitrogen for the zooxanthellae in mudflat anemones, and may explain the marked difference in nitrogen status between the mudflat and rocky shore populations.

Generalist dinoflagellate endosymbionts and host genotype diversity detected from mesophotic (67-100 m depths) coral Leptoseris

by Rob Toonen

Mesophotic corals (light-dependent corals in the deepest half of the photic zone at depths of 30 – 150 m) provide a... more Mesophotic corals (light-dependent corals in the deepest half of the photic zone at depths of 30 – 150 m) provide a unique opportunity to study the limits of the interactions between corals and endosymbiotic dinoflagellates in the genus Symbiodinium. We sampled Leptoseris spp. in Hawaii via manned submersibles across a depth range of 67 – 100 m. Both the host and Symbiodinium communities were genotyped, using a non-coding region of the mitochondrial ND5 intron (NAD5) and the nuclear ribosomal internal transcribed spacer region 2 (ITS2), respectively.

A hydrozoan, Zanclella bryozoophila n.gen.; n. sp. (Zancleidae), symbiotic with a bryozoan, with a discussion of the Zancleoidea

by Chad Hewitt

Boero, F., and Hewitt C.L. 1992. A hydrozoan, Zanclella bryozoophila n.gen., n.sp. (Zancleidae), symbiotic with a bryozoan, with a discussion of the Zancleoidea. Can. J. Zool. 70: 1645 - 1651

A new genus and species of hydroid, Zanclella bryozoophila, symbiotic with bryozoans is described. The colony is... more A new genus and species of hydroid, Zanclella bryozoophila, symbiotic with bryozoans is described. The colony is polymorphic and highly integrated with its bryozoan host. The gastrozooids have one or, rarely, two tentacles; dactylozooids are without tentacles. The medusa stage is reduced to liberable eumedusoids produced on the hydrorhiza, and has exumbrellar
nematocyst chambers. 'The cnidome of both stages consists of  stenoteles and macrobasic euryteles. General morphology and cnidome structure place this newly described form in the Zancleidae. A new genus is recognized on the basis of polymorphism of the hydroid and reduction of the medusa stage. The association with the bryozoan is described as commensal. Hydranths appear to feed on particles gathered by ciliary action of the bryozoan lophophore, and the hydrorhiza is surrounded by the bryozoan skeleton. The advantage of this relationship to the bryozoan is believed to be protection, effected by the nematocysts of the hydroid.

Macrosymbiotic association of the myid bivalve Cryptomya with thalassinidean shrimps: Examples from modern and Pleistocene tidal flats of Japan

by Masakazu Nara

A Single Streptomyces Symbiont Makes Multiple Antifungals to Support the Fungus Farming Ant Acromyrmex octospinosus

by Douglas Yu

Seipke R.F., Barke J., Brearley C., Hill L., Yu D.W., Goss R.J.M. & Hutchings M.I. (2011). A single Streptomyces mutualist makes multiple antifungals to support the fungus farming ant Acromyrmex octospinosus PLoS ONE, 6, e22028.

Attine ants are dependent on a cultivated fungus for food and use antibiotics produced by symbiotic Actinobacteria as... more Attine ants are dependent on a cultivated fungus for food and use antibiotics produced by symbiotic Actinobacteria as weedkillers in their fungus gardens. Actinobacterial species belonging to the genera Pseudonocardia, Streptomyces and Amycolatopsis have been isolated from attine ant nests and shown to confer protection against a range of microfungal weeds. In previous work on the higher attine Acromyrmex octospinosus we isolated a Streptomyces strain that produces candicidin, consistent with another report that attine ants use Streptomyces-produced candicidin in their fungiculture. Here we report the genome analysis of this Streptomyces strain and identify multiple antibiotic biosynthetic pathways. We demonstrate, using gene disruptions and mass spectrometry, that this single strain has the capacity to make candicidin and multiple antimycin compounds. Although antimycins have been known for .60 years we report the sequence of the biosynthetic gene cluster for the first time. Crucially, disrupting the candicidin and antimycin gene clusters in the same strain had no effect on bioactivity against a co-evolved nest pathogen called Escovopsis that has been identified in ,30% of attine ant nests. Since the Streptomyces strain has strong bioactivity against Escovopsis we conclude that it must make additional antifungal(s) to inhibit Escovopsis. However, candicidin and antimycins likely offer protection against other microfungal weeds that infect the attine fungal gardens. Thus, we propose that the selection of this biosynthetically prolific strain from the natural environment provides A. octospinosus with broad spectrum activity against Escovopsis and other microfungal weeds.

Malic enzyme activity in bacteroids from soybean nodules

by Rosanne Quinnell

Copeland L, Quinnell RG, Day DA. 1989. Microbiology 135: 2005-2011
http://mic.sgmjournals.org/content/135/7/2005.short
doi: 10.1099/00221287-135-7-2005

Soluble extracts of Bradyrhizobium japonicum bacteroids from soybean root nodules showed substantial rates of NAD+ and... more Soluble extracts of Bradyrhizobium japonicum bacteroids from soybean root nodules showed substantial rates of NAD+ and NADP+ reduction which were malate and MnCl2 dependent. Pyruvate was formed stoichiometrically and the NAD- and NADP-dependent rates were additive, indicating the presence of two malic enzymes. The NADP-dependent malic enzyme had a high affinity for malate (apparent Km = 0·1 mM) and was stimulated by ammonium. The NAD-dependent malic enzyme had a lower affinity for malate (apparent Km = 1·9 mM) and was stimulated by potassium and ammonium salts. The maximum velocities of the two enzymes were similar and of comparable magnitude to the activities of tricarboxylic acid cycle enzymes in the extracts. Possible roles of the malic enzymes in the metabolism of malate and succinate in bacteroids are discussed.

Isolation of symbiosomes and the symbiosome membrane complex from the zoanthid Zoanthus robustus

by Rosanne Quinnell

Aniuska Kazandjian, Virginia A. Shepherd, Mauricio Rodriguez-Lanetty, Wiebke Nordemeier, Anthony W. D. Larkum, and Rosanne G. Quinnell (2008) Phycologia: May 2008, Vol. 47, No. 3, pp. 294-306

The zoanthid Zoanthus robustus was used as a model organism to develop procedures for isolating pure symbiosomes and... more The zoanthid Zoanthus robustus was used as a model organism to develop procedures for isolating pure symbiosomes and symbiosome membranes. The symbiosome is comprised of a zooxanthella (Symbiodinium sp.) cell that divides rarely and is separated from the host gastrodermal cytoplasm by a symbiosome multimembrane complex. Devising a method to isolate membranes at the interface between the symbiotic partners is a critical first step in characterising the molecular components involved in the metabolic trafficking necessary to sustain an effective symbiosis. After zoanthid gastrodermal cells were extracted, symbiosomes were released by mechanical disruption, recovered by centrifugation, and then purified using discontinuous sucrose gradient centrifugation. The material forming the membrane complex around symbiosomes proved highly resistant to disruption. Methods used to dissociate this interface from symbionts included (1) Triton X-100 detergent solubilisation, (2) osmotic shock with mechanical disruption, and (3) vigorous mechanical disruptions, where powerful shearing forces were used, combined with a series of sucrose density gradient centrifugation steps. The lipophilic styryl fluorochrome FM 1-43, at a concentration of 30 µM, selectively labelled the symbiosome membrane complex, both for isolated symbiosomes and those in hospite. Other cell membranes, including plasma membranes, endoplasmic reticulum, tonoplast, and organelle membranes, were not visibly labelled at this concentration. The selective labelling of the symbiosome membrane complex remained stable even after long exposure times (3 h). At 30 µM concentration, FM 1-43 also labelled symbiosome membrane fragments isolated using methods (1), (2) and (3). Method (3) proved to be the most effective in producing a fraction enriched in FM-143-labelled membrane material, which we call a symbiosome membrane complex. Transmission electron microscopy, together with confocal and conventional epifluorescence microscopy of the FM 1-43-stained preparations, was used to validate the purity of symbiosome preparations and to infer the complexity of the symbiosome membrane complex. This membrane complex has regions where the membranes contributed by the alga are appressed, and punctate regions whose function remains unclear.

Symbiotic relationship between Cerrena unicolor and the horntail Tremex fuscicornis recorded in the Czech Republic

by Sylvie Pazoutova

Czech Mycol 59:83-90 (2007)

From a specimen of Acer saccharinus collected in a Prague park, 38 females of Tremex fuscicornis (Hymenoptera,... more From a specimen of Acer saccharinus collected in a Prague park, 38 females of Tremex fuscicornis (Hymenoptera, Siricidae) were reared and sixteen isolates of a symbiotic basidiomycete were isolated from their mycangia. All isolates shared morphology and RAPD patterns. The fungus was identified using rDNA (regions ITS1, 5.8S, ITS2, and D1D2 part of the 28S rDNA) as Cerrena unicolor (Basidiomycota: Polyporales). The identification is discussed with respect to related horntail taxa and former identification attempts