Women in tunicate research: Pioneers of the past and their present legacy.

The search for female scientists who pioneered the research on tunicates is hindered by the tradition of reporting only the first initials of authors' names on scientific publications using only the initials of their first names. While this practice has the theoretical merit of broadening the readership by preventing the possible bias that could be caused by the gender of the author(s) in some of the readers, it rendered the identification of female researchers active in, or before, the first half of the 20th century quite challenging. Sifting through several dozen electronic records, and with the help of references and/or quotes found online, we have stitched together the information that we were able to retrieve on the life of female scientists who authored some of the earliest publications on tunicates, and we have organized them in (approximate) chronological order. We have also compiled brief synopses of the findings of scientists active in the field of tunicate biology in more recent times, and organized them by subdiscipline.

Nephromyces Encodes a Urate Metabolism Pathway and Predicted Peroxisomes, Demonstrating That These Are Not Ancient Losses of Apicomplexans.

The phylum Apicomplexa is a quintessentially parasitic lineage, whose members infect a broad range of animals. One exception to this may be the apicomplexan genus Nephromyces, which has been described as having a mutualistic relationship with its host. Here we analyze transcriptome data from Nephromyces and its parasitic sister taxon, Cardiosporidium, revealing an ancestral purine degradation pathway thought to have been lost early in apicomplexan evolution. The predicted localization of many of the purine degradation enzymes to peroxisomes, and the in silico identification of a full set of peroxisome proteins, indicates that loss of both features in other apicomplexans occurred multiple times. The degradation of purines is thought to play a key role in the unusual relationship between Nephromyces and its host. Transcriptome data confirm previous biochemical results of a functional pathway for the utilization of uric acid as a primary nitrogen source for this unusual apicomplexan.

Nephromyces, a beneficial apicomplexan symbiont in marine animals.

With malaria parasites (Plasmodium spp.), Toxoplasma, and many other species of medical and veterinary importance its iconic representatives, the protistan phylum Apicomplexa has long been defined as a group composed entirely of parasites and pathogens. We present here a report of a beneficial apicomplexan: the mutualistic marine endosymbiont Nephromyces. For more than a century, the peculiar structural and developmental features of Nephromyces, and its unusual habitat, have thwarted characterization of the phylogenetic affinities of this eukaryotic microbe. Using short-subunit ribosomal DNA (SSU rDNA) sequences as key evidence, with sequence identity confirmed by fluorescence in situ hybridization (FISH), we show that Nephromyces, originally classified as a chytrid fungus, is actually an apicomplexan. Inferences from rDNA data are further supported by the several apicomplexan-like structural features in Nephromyces, including especially the strong resemblance of Nephromyces infective stages to apicomplexan sporozoites. The striking emergence of the mutualistic Nephromyces from a quintessentially parasitic clade accentuates the promise of this organism, and the three-partner symbiosis of which it is a part, as a model for probing the factors underlying the evolution of mutualism, pathogenicity, and infectious disease.

Themes from variation: probing the commonalities of symbiotic associations.

Research on symbiosis (including antagonistic and mutualistic associations) wrestles, directly or indirectly, with the paradox: why are symbiotic associations so prevalent in the biosphere in the face of ubiquitous immune or antibiotic defenses among organisms? The symposium "Living Together: the Dynamics of Symbiotic Interactions" considered several questions: 1. How do symbiotic species partners come together? Do symbioses share similar patterns of signal recognition and response? 2. What roles do nutrients and metabolites play in symbiotic interactions, and how are metabolic exchanges affected by environmental changes? 3. In what ways do the dynamics of multispecies symbioses differ from two-species associations? 4. How do antagonistic (parasitic, pathogenic) symbioses differ from mutualistic ones? In what ways do changes in the biotic and physical environment affect the evolutionary balance of symbiotic associations? 5. What are the coevolutionary patterns of symbiotic associations? 6. Which research techniques, and strategies of experimental design, might be useful across a broad range of symbiotic associations?Two themes emerged from the symposium. First, all the participants have incorporated multiple techniques and perspectives into their work, approaches which facilitate the understanding of symbiotic dynamics at several levels of biological organization. Secondly, many of the papers addressed genetic and environmental variation in symbiotic interactions. Such approaches are useful tools for analysis of the mechanics of interspecies interactions and for characterization of the most important factors which influence them. They provide us with the tools to evaluate symbioses in a world of complexity, variation and change.