Unseen Forces: The Influence of Bacteria on Animal Development

Abstract

The diversity of developmental programs present in animal phyla first evolved within the world's oceans, an aquatic environment teeming with an abundance of microbial life. All stages in the life histories of these early animals became adapted to microorganisms bathing their tissues, and countless examples of animal-bacterial associations have arisen as a result. Thus far, it has been difficult for biologists to design ways of determining the extent to which these associations have influenced the biology of animals, including their developmental patterns. The following review focuses on an emerging field, the goal of which is to understand the influence of bacteria on animal developmental programs. This integrative area of research is undergoing a revolution that has resulted from advances in technology and the development of suitable animal-bacterial systems for the study of these complex associations. In this contribution, the current status of the field is reviewed and the emerging research horizons are examined.

Drosophila lifespan enhancement by exogenous bacteria

“…longevity ͉ aging ͉ axenic flies ͉ antibiotics M icroorganisms have been a major factor in shaping eukaryotic evolution (1). Because the embryonic development of most animals occurs under germ-free conditions, the establishment of a resident fauna is a dynamic process, the initial exposure at birth or hatching determining which bacteria have primary access to the host (2).…”

Vibrio pacinii sp. nov., from cultured aquatic organisms

“…Some Vibrio species may also have a beneficial effect in host organisms, either as symbionts [e.g. of squids (McFall-Ngai, 2002)] or probionts (Gomez-Gil et al, 2000). Several studies have investigated phenotypic diversity of vibrios in aquaculture environments (Vandenberghe et al, 1998.…”

Organisms or biological individuals? Combining physiological and evolutionary individuality

“…Most of them are. But being an interactor comes in degrees, and it can perfectly well happen that a given physiological individual displays a low degree of interactor-like individuality (examples include group selection in some social insects (Wilson and Sober 1989), or strong cellular selection at the 19 Contrary to a frequent assumption, horizontal associations are not necessarily more recent and less indispensable for the host than vertical associations (McFall-Ngai 2002;Ebert 2013). 20 Interestingly, Wilson and Sober (op.…”