Tissue distribution of neutral deoxyribonuclease (DNase) activity in the mussel Mytilus galloprovincialis

From shells to sequences: A proof-of-concept study for on-site analysis of hemolymphatic circulating cell-free DNA from sentinel mussels using Nanopore technology

Blue mussels are often abundant and widely distributed in polar marine coastal ecosystems. Because of their wide distribution, ecological importance, and relatively stationary lifestyle, bivalves have long been considered suitable indicators of ecosystem health and changes. Monitoring the population dynamics of blue mussels can provide information on the overall biodiversity, species interactions, and ecosystem functioning. In the present work, we combined the concept of liquid biopsy (LB), an emerging concept in medicine based on the sequencing of free circulating DNA, with the Oxford Nanopore Technologies (ONT) platform using a portable laboratory in a remote area. Our results demonstrate that this platform is ideally suited for sequencing hemolymphatic circulating cell-free DNA (ccfDNA) fragments found in blue mussels. The percentage of non-self ccfDNA accounted for >50 % of ccfDNA at certain sampling Sites, allowing the quick, on-site acquisition of a global view of the biodiversity of a coastal marine ecosystem. These ccfDNA fragments originated from viruses, bacteria, plants, arthropods, algae, and multiple Chordata. Aside from non-self ccfDNA, we found DNA fragments from all 14 blue mussel chromosomes, as well as those originating from the mitochondrial genomes. However, the distribution of nuclear and mitochondrial DNA was significantly different between Sites. Similarly, analyses between various sampling Sites showed that the biodiversity varied significantly within microhabitats. Our work shows that the ONT platform is well-suited for LB in sentinel blue mussels in remote and challenging conditions, enabling faster fieldwork for conservation strategies and resource management in diverse settings.

Preparation of konjac glucomannan hydrogels as DNA-controlled release matrix

In this study, hydrogels for DNA-controlled release was prepared with konjac glucomannan (KGM), a water-soluble non-ionic polysaccharide, by means of deacetylated reaction and physically cross-linking method under mild conditions. The properties of the KGM hydrogels were analyzed by FTIR spectra and scanning electron microscopy (SEM). The integrality of the released DNA was investigated by circular dichroism (CD). The DNA release kinetics was performed using the DNA-loaded KGM gels in buffer solutions of pH 7.4 at 37+/-0.5 degrees C. Peppas model and Higuchi model were used to analysis the DNA release mechanism; the data indicated that the DNA release can be controlled by changing the preparation conditions and the structure parameters of the gels. This study suggested that the KGM hydrogels have a potential use for advanced controlled release.