Oysters construct extensive reef communities, providing food, protection from storms, and healthy coastlines. We still do not have a clear picture of how these animals attach to surfaces. Efforts described herein provide the first examination of adhesion at the transition from free swimming larvae to initial substrate attachment, through metamorphosis, and on to adulthood. Two different bonding systems were found to coexist. Larvae use an organic, hydrated glue that persists while the animal progresses into the juvenile phase, at which point a very different adhesive emerges. Juveniles bond with an organic-inorganic composite system, positioning the organic component for maximum adhesion by residing between the animal and substrate. Beyond understanding our marine environment, these insights may aid efforts in aquaculture, reef restoration, and adhesive design.

Parasites belonging to the Apicomplexa phylum are among the most successful pathogens known in nature. They can infect a wide range of hosts, often remain undetected by the immune system, and cause acute and chronic illness.

Animals with a chronic infection of the parasite Toxoplasma gondii are protected against lethal secondary infection with other pathogens. Our group previously determined that soluble T. gondii antigens (STAg) can mimic this protection and be used as a treatment against several lethal pathogens. Because treatments are limited for the parasite Cryptosporidium parvum , we tested STAg as a C. parvum therapeutic. We determined that STAg treatment reduced C. parvum Iowa II oocyst shedding in IFNγ-KO mice. Murine intestinal sections were then sequenced to define the IFNγ independent transcriptomic response to C. parvum infection. Gene Ontology and transcript abundance comparisons showed host immune response and metabolism changes. Transcripts for type I interferon responsive genes were more abundant in C. parvum infected mice treated with STAg. Comparisons between PBS or STAg treatments showed no significant differences in C. parvum gene expression. C. parvum transcript abundance was highest in the ileum and mucin-like glycoproteins and the GDP-fucose transporter were among the most abundant. These results will assist the field in determining both host- and parasite-directed future therapeutic targets.

The cement produced by the Eastern oyster, Crassostrea virginica, may provide blueprints for waterproof biocompatible adhesives synthesized under benign conditions. The composition of this organic−inorganic composite, and of an organic extract, was characterized by 13 C and 1 H solid-state NMR and also compared with C. virginica shell and its organic extract. Quantification of the organic fraction by 13 C and 1 H NMR spectroscopy consistently showed 3 wt % organics in cement, which was higher than the 1.2 wt % in the shell. According to 13 C NMR with spectral editing, the organic fraction of cement consisted of 73% protein, 25% polysaccharide, and 2% lipid. The organic acid-insoluble extract from the cement was mostly made up of protein remarkably rich in alanine and glycine. The unusual amino acid content matched the composition of silk-like proteins in the C. virginica or C. gigas genomes, including spidron-1-like and shelk2 previously found to be upregulated at the mantle edge. The corresponding extract from the shell contained 32% glycine and was also enriched in serine but not alanine, which was consistent with a previous wet-chemistry study. The 13 C and 1 H NMR spin−lattice relaxation in the organic component of cement and the acidinsoluble extract was 4−40 times faster than in the shell and showed pronounced nonexponentiality, indicating a high concentration of persistent radicals in the organic components of cement, in agreement with a prior EPR study. The presence of radicals in the acid-insoluble cement fraction was confirmed by observation of a paramagnetic shift anisotropy. 13 C NMR corroborated prior observations that the calcium carbonate in the shell and pseudonacre was mostly calcite, whereas cement had an enhanced aragonite fraction. Surprisingly, 1 H− 13 C NMR indicated that aragonite in cement was more distant from the organic fraction than was calcite. These results help advance our understanding of how oysters achieve adhesion within their wet environment.

polarity of the amino acid chain is influential in the induced membrane permeability of these peptides. In addition, these in-vitro studies imply the existence of a factor or a combination of factors aside from strictly membrane sterol content that determines the specificity of these antimicrobial peptides for fungal cells in-vivo. Importantly, the results of this study imply that the relative spatial position of the amino acids in histatin 5 is critical for the antifungal activity.