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Natural hydroxyapatite (HA), derived from waste bones of several animal species, has received much attention as a material for bone grafts and fillers and has a role as a coating for metal implants because of its biocompatibility and non-toxicity. To investigate the applicability of HA derived from waste bones of novel animal sources, the biocompatibility and toxicity of a poly-l-lactic acid (PLA)-based composite containing HA derived from the backbone of the dolphin Neophocaena asiaeorientalis (HANA) were examined in Sprague-Dawley (SD) rats. HANA powder showed X-ray diffraction peak patterns that corresponded to those of standard HA. Among five composites prepared from different combinations of PLA and HANA (7:3, 6:4, 5:5, 4:6, and 3:7), a PLA/HANA composite manufactured with a 6:4 PLA:HANA ratio had high surface roughness (453 nm), 10.3 N of maximum load, and 451.9 MPa of module elasticity. After implantation in the subcutaneous region of SD rats for 8 weeks, the amount of confluent, aggregated structures of multilayered cells on the PLA/HANA implant surface was greater than that on the PLA surface, although both implants were completely covered with adhesive cells. During the implant period, the initial intact form of the PLA/HANA composite broke into small fragments with few inflammatory cells in the contact region and no indication of significant toxicity. Taken together, the results suggest that HANA may have good biocompatibility and be non-toxic as it did not induce an immune response in SD rats.

The pinnipeds, which comprise seals, sea lions, and walruses, are a remarkable group of marine animals with unique adaptations to semi-aquatic life. However, their genomes are poorly characterized. In this study, we sequenced and characterized the genomes of three pinnipeds (Phoca largha, Callorhinus ursinus, and Eumetopias jubatus), focusing on site-wise sequence changes. We detected rapidly evolving genes in pinniped lineages and substitutions unique to pinnipeds associated with amphibious sound perception. Phenotypic convergence-related sequence convergences are not common in marine mammals. For example, FASN, KCNA5, and IL17RA contain substitutions specific to pinnipeds, yet are potential candidates of phenotypic convergence (blubber, response to hypoxia, and immunity to pathogens) in all marine mammals. The outcomes of this study will provide insight into targets for future studies of convergent evolution or gene function.

Larger organisms tend to live longer, have more potentially carcinogenic cells, and undergo more cell divisions. While one might intuitively expect cancer incidence to scale with body size, this assertion does not hold over the range of different mammals. Explaining this lack of correlation, so-called ‘Peto’s paradox’ can likely increase our understanding of how cancer defense mechanisms are shaped by natural selection. Here, we study the occurrence of microsatellite in mammal genomes and observe that animals with expanded body size restrain the number of microsatellite. To take into account of higher mutation rate in the microsatellite region compared to that of genome, limiting the abundance of somatic mutations might explain how larger organisms could overcome the burden of cancer. These observations may serve as the basis to better understand how evolution has modeled protective mechanisms against cancer development.

Concentrations of trace metals (As, Cd, Cr, Cu, Pb, Hg, Se, and Zn) were determined in the livers, kidneys, muscles, intestines, and hearts of twelve long-beaked common dolphins (Delphinus capensis) from the East Sea, Korea, in 2006. All specimens were entangled in various commercial fishing nets or traps and as such are recorded as by-catch. The concentrations of Cu, Hg, Se, and Zn were much higher in the liver than in the kidney, muscle, intestine, or heart. Trace metals that accumulated in the liver were, in descending order: Zn > Hg > Cd > Se > Cu > As > Cr > Pb. In contrast, the concentration of Cd was higher in the kidney than in any other organs. The trace metals accumulated in the kidney were, in descending order: Cd > Zn > Cu > Hg > Se > As > Pb > Cr. No significant differences were found in the concentrations of As, Cr, or Pb in all the tissues examined.

Some whales caught incidentally or illegally in Korean waters have been introduced into the seafood market. Thus, the Korea Coast Guard (KCG) monitors and reports incidentally caught whales. However, species identification of some carcasses based on morphological features is difficult and often inaccurate, particular for processed whale products in the marketplace. For these reasons, we developed a DNA microarray that distinguishes 9 species of cetacean animals for quick and simple species identification. We verified genetic variations in whales and designed species-specific oligonucleotide probes by sequence analysis of mitochondrial cytochrome c oxidase subunit I. Fluorescent dye-labeled DNA targets were generated with a fluorescent dye-labeled primer and hybridized onto a DNA microarray consisting of short probes that were 29-37 nucleotides in length. A DNA microarray system using species-specific probes was successful at rapidly identifying 9 species of whales on the basis of hybridization patterns.

Data on levels and accumulation profiles of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/ Fs) and dioxin-like polychlorinated biphenyls (PCBs) in cetaceans are scarce. This paper presents data on the concentrations and accumulation features of PCDD/Fs and dioxin-like PCBs in muscle of minke whales (Balaenoptera acutorostrata) and long-beaked common dolphins (Delphinus capensis) collected from Korean coastal waters. The residue levels in cetaceans were in the order of mono-ortho PCBs> non-ortho PCBs>PCDFs>PCDDs. Total toxic equivalent (TEQ) concentrations in muscle of minke whales and common dolphins from Korea were lower than those reported for cetaceans and seals from other countries. The accumulation profiles of PCDD/Fs and dioxin-like PCBs were different between the cetacean species. Concentrations of PCDD/Fs and dioxin-like PCBs in common dolphins were significantly higher than those measured in minke whales, due to differences in the habitat and diet. The relative contribution of individual chemical groups to total TEQs was different between the cetacean species, suggesting different exposures and metabolic activity.