Bioluminescence, a phenomenon observed widely in organisms ranging from bacteria to metazoans, has a significant impact on the behaviour and ecology of organisms. Among bioluminescent organisms, Polycirrus, which has unique emission wavelengths, has received attention, and advanced studies such as RNA-Seq have been conducted, but they are limited to a few cases. In addition, accurate species identification is difficult due to lack of taxonomic organization. In this study, we conducted comprehensive taxonomic survey of Japanese Polycirrus based on multiple specimens from different locations and described as three new species: Polycirrus onibi sp. nov., P. ikeguchii sp. nov. and P. aoandon sp. nov. The three species can be distinguished from the known species based on the following characters: (i) arrangement of mid-ventral groove, (ii) arrangement of notochaetigerous segments, (iii) type of neurochaetae uncini, and (iv) arrangement of nephridial papillae. By linking the bioluminescence phenomenon with taxonomic knowledge, we established a foundation for future bioluminescent research development. We also provide a brief phylogenetic tree based on cytochrome c oxidase subunit I (COI) sequences to discuss the evolution of bioluminescence and the direction of future research.
This study promotes the use of nanobiochar (NBC) as an environmentally friendly substitute to conventional fillers to improve various properties of biopolymers such as their mechanical strength, thermal stability and crystallization properties. TGA analysis showed a slight increase in onset thermal degradation temperature of the composites by up to 5 °C with the addition of 4 wt% NBC. Non-isothermal DSC analysis determined that the addition of NBC into PHBHHx increases the crystallization temperature and degree of crystallinity of PHBHHx while isothermal DSC analysis demonstrated higher crystallization rate in PHBHHx/NBC composited by up to 54%. PHBHHx incorporated with NBC also exhibited superior tensile strength and modulus versus neat PHBHHx. Increase in mechanical strength was further proven via DMA where PHBHHx/NBC composites maintained higher storage modulus at higher temperatures when compared to neat PHBHHx. PHBHHx/NBC also exhibited no cytotoxicity effect against HaCat cells. This study demonstrates the ability of biochar to act as both nucleating agents and reinforcing agents in biodegradable polymers such as PHBHHx, which could be suitable for packaging application.