Episodes of coral bleaching (loss of the symbiotic dinoflagellates) and coral mortality have occurred with increasing frequency over the past two decades. Although some corals recover from bleaching events, the source of the repopulating symbionts is unknown. Here we show that after bleaching, the adult octocoral Briareum sp. acquire dinoflagellate symbionts (Symbiodinium sp.) from the environm...

Many organisms harbor microbial associates that have profound impacts on host traits. The phenotypic effect of symbionts on their hosts may include changes in development, reproduction, longevity, and defense against natural enemies. Determining the consequences of associating with a microbial symbiont requires experimental comparison of hosts with and without symbionts. Then, determining the m...

Previously, analysis of 16S rDNA sequences placed a newly discovered lineage of bacterial symbionts of arthropods in the 'Bacteroidetes'. This symbiont lineage is associated with a number of diverse host reproductive manipulations, including induction of parthenogenesis in several Encarsia parasitoid wasps (Hymenoptera: Aphelinidae). In this study, electron microscopy and phylogenetic analysis ...

The ultrastructure of Chlorella-like algal endosymbionts from the Florida and English strains of green hydra was compared under different host feeding and photoperiodic regimes. Under standard conditions (host fed daily, 12-h photoperiod) the algae from the 2 strains exhibited considerable differences. The English symbionts had a pyrenoid, compact chloroplast membranes and vesiculated polyphosp...

Marine nematodes that carry sulfur-oxidizing bacteria on their cuticle (Stilbonematinae, Desmodoridae) migrate between oxidized and reduced sand layers thereby supplying their symbionts with oxygen and sulfide. These symbionts, in turn, constitute the worms' major food source. Due to the accessibility, abundance and relative simplicity of this association, stilbonematids may be useful to unders...

Some bacterial symbionts alter their hosts reproduction through various mechanisms that enhance their transmission in the host population. In addition to its obligatory symbiont Buchnera aphidicola, the pea aphid Acyrthosiphon pisum harbors several facultative symbionts influencing several aspects of host ecology. Aphids reproduce by cyclical parthenogenesis whereby clonal and sexual reproducti...

The siboglinid tubeworm Sclerolinum contortum symbiosis inhabits sulfidic sediments at deep-sea hydrocarbon seeps in the Gulf of Mexico. A single symbiont phylotype in the symbiont-housing organ is inferred from phylogenetic analyses of the 16S ribosomal ribonucleic acid (16S rRNA) gene and fluorescent in situ hybridization. The phylotype we studied here, and a previous study from an arctic hyd...

The large tropical lucinid clam Codakia orbicularis has a symbiotic relationship with intracellular, sulfide-oxidizing chemoautotrophic bacteria. The respiration strategies utilized by the symbiont were explored using integrative techniques on mechanically purified symbionts and intact clam-symbiont associations along with habitat analysis. Previous work on a related symbiont species found in t...

BACKGROUND AND AIMS The large monophyletic genus Mimosa comprises approx. 500 species, most of which are native to the New World, with Central Brazil being the main centre of radiation. All Brazilian Mimosa spp. so far examined are nodulated by rhizobia in the betaproteobacterial genus Burkholderia. Approximately 10 Mya, transoceanic dispersal resulted in the Indian subcontinent hosting up to s...

Recent research has shown that the bacterial endosymbionts of insects are abundant and diverse, and that they have numerous different effects on their hosts' biology. Here we explore how insect endosymbionts might affect the structure and dynamics of insect communities. Using the obligate and facultative symbionts of aphids as an example, we find that there are multiple ways that symbiont prese...