Nephridial (excretory organ) symbionts are widespread in lumbricid earthworms and the complexity of the nephridial symbiont communities varies greatly between earthworm species. The two most common symbionts are the well-described Verminephrobacter and less well-known Flexibacter-like bacteria. Verminephrobacter are present in almost all lumbricid earthworms, they are species-specific, vertical...

Facultative or "secondary" symbionts are common in eukaryotes, particularly insects. While not essential for host survival, they often provide significant fitness benefits. It has been hypothesized that secondary symbionts form a "horizontal gene pool" shuttling adaptive genes among host lineages in an analogous manner to plasmids and other mobile genetic elements in bacteria. However, we do no...

The pink shrimp Farfantepenaeus duorarum may acquire pollutants, helminths and symbionts from their environment. Statistical associations were studied between the symbionts and helminths of F. duorarum and pollutants in sediments, water and shrimps in Campeche Sound, Mexico. The study area spatially overlapped between offshore oil platforms and natural shrimp mating grounds. Spatial autocorrela...

Highly reduced genomes of 144-416 kilobases have been described from nutrient-provisioning bacterial symbionts of several insect lineages [1-5]. Some host insects have formed stable associations with pairs of bacterial symbionts that live in specialized cells and provide them with essential nutrients; genomic data from these systems have revealed remarkable levels of metabolic complementarity b...

Symbiotic relationships with bacteria are common within the Arthropoda, with interactions that substantially influence the biology of both partners. The symbionts' spatial distribution is essential for understanding key aspects of this relationship, such as bacterial transmission, phenotype, and dynamics. In this study, fluorescence in situ hybridization was used to localize five secondary symb...

ALMOST ALL LUMBRICID EARTHWORMS (OLIGOCHAETA Lumbricidae) harbor extracellular species-specific bacterial symbionts of the genus Verminephrobacter (Betaproteobacteria) in their nephridia. The symbionts have a beneficial effect on host reproduction and likely live on their host's waste products. They are vertically transmitted and presumably associated with earthworms already at the origin of Lu...

Abstract 'Candidatus Cardinium', a recently described bacterium from the Bacteroidetes group, is involved in diverse reproduction alterations of its arthropod hosts, including cytoplasmic incompatibility, parthenogenesis and feminization. To estimate the incidence rate of Cardinium and explore the limits of its host range, 99 insect and mite species were screened, using primers designed to ampl...

Larvae of the bryozoan Bugula neritina harbor bacterial symbionts. These symbionts were identified as a novel species of gamma-proteobacterium, based on ribosomal small-subunit rRNA gene sequences. In situ hybridization with oligonucleotides specific for the symbiont confirmed the origin of the sequence. The taxonomic status "Candidatus Endobugula sertula" is proposed for the larval symbiont.

In this minireview, we address the trade-off between biological altruism (group adaptation result-ing from ability of an organism to improve fitness associate at expense its own fitness) and symbiogenesis — evolutionary pathway based on genetic integration non-related species. We as a multi-stage process, which involves for-mation superspecific hereditary systems functionally integral symbiogen...

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' (st...