Project description:Humans harbor numerous species of colonic bacteria that digest the fiber polysaccharides in commonly consumed terrestrial plants. More recently in history, regional populations have consumed edible seaweeds (macroalgae) containing unique polysaccharides. However, it remains unclear how extensively gut bacteria have adapted to digest these novel nutrients. Here, we show that the ability of gut bacteria to digest seaweed polysaccharides is considerably more pervasive than previously appreciated. Using culture-based approaches, we show that known Bacteroides genes involved in seaweed degradation have mobilized into many members of this genus. We also identify new marine bacteria-derived genes, and their corresponding mobile DNA elements, that are involved in degrading several seaweed polysaccharides. Some of these new genes reside in gut-resident, Gram-positive Firmicutes, for which phylogenetic analysis suggests an origin in the Epulopiscium gut symbionts of marine fishes. Our results are important for understanding the metabolic plasticity of the human gut microbiome, the global exchange of genes in the context of dietary selective pressures and identifying new functions that can be introduced or engineered to design and fill orthogonal niches for a future generation of engineered probiotics.
Project description:The marine world is incredibly rich in brilliant and intense colours. Photonic structures are found in many different species and provide extremely complex optical responses that cannot be achieved solely by pigments. In this study we examine the cuticular structure of the red alga Chondrus crispus (Irish Moss) using anatomical and optical approaches. We experimentally measure the optical response of the multilayer structure in the cuticle. Using finite-difference time-domain modelling, we demonstrate conclusively for the first time that the dimensions and organisation of lamellae are responsible for the blue structural colouration on the surface of the fronds. Comparison of material along the apical-basal axis of the frond demonstrates that structural colour is confined to the tips of the thalli and show definitively that a lack of structural colour elsewhere corresponds with a reduction in the number of lamellae and the regularity of their ordering. Moreover, by studying the optical response for different hydration conditions, we demonstrate that the cuticular structure is highly porous and that the presence of water plays a critical role in its ability to act as a structural light reflector.
Project description:This study aimed at identification of genetic regulations for desiccation tolerance in intertidal seaweed species Ulva lactuca most commonly experienced phenomenon of intertidal communities.