Allorecognition proteins in an invertebrate exhibit homophilic interactions.

Sessile colonial invertebrates-animals such as sponges, corals, bryozoans, and ascidians-can distinguish between their own tissues and those of conspecifics upon contact [1]. This ability, called allorecognition, mediates spatial competition and can prevent stem cell parasitism by ensuring that colonies only fuse with self or close kin. In every taxon studied to date, allorecognition is controlled by one or more highly polymorphic genes [2-8].

Analyzing cell physiology in C. elegans with fluorescent ratiometric reporters.

Ratiometric fluorescent reporters have recently emerged a new technique to non-invasively measure aspects of cell physiology such as redox status, calcium levels, energy production, and NADH levels. These reporters consist of either a single or pair of fluorophores along with specific modifications, such as the addition of a protein domain which binds to a metabolite of interest, thereby producing gradual alterations in fluorescence in response to changes in the measured parameter. Measurement of the changes in fluorescence produces a quantitative read-out of the cellular environment.

Characterization of the nutritional endoderm in the direct developing frog Eleutherodactylus coqui.

Unlike Xenopus laevis, Eleutherodactylus coqui develops without a tadpole. The yolk-rich vegetal region of the embryo forms a transient nutritive tissue, the nutritional endoderm (NE). The definitive endoderm (DE) in E.

Nutritional endoderm in a direct developing frog: a potential parallel to the evolution of the amniote egg.

The egg of the direct-developing frog, Eleutherodactylus coqui, has 20 x the volume as that of the model amphibian, Xenopus laevis. Increased egg size led to the origin of nutritional endoderm, a novel cell type that provides nutrition but does not differentiate into digestive tract tissues. As the E.