Intrinsic factor and vitamin B12 complex-loaded poly[lactic-co-(glycolic acid)] microspheres: preparation, characterization and drug release

Transcriptome sequencing reveals phagocytosis as the main immune response in the pathogen-challenged sea urchin Strongylocentrotus intermedius

The clarification of host immune responses to causative bacteria of spotting disease in the sea urchin Strongylocentrotus intermedius is vital to preventing and controlling this disease, especially to selective breeding for disease resistance. For this purpose, sea urchins were challenged with the causative bacterium Vibrio sp. to obtain spotting diseased and undiseased samples. We conducted next-generation sequencing to assess the key genes/pathways in control (CG), diseased (DG), and undiseased (UG) groups. A total of 454.1 million clean reads were obtained and assembled into 23,899 UniGenes with an N50 of 1359 bp, with 86.11% of them matching the genome sequence of the sea urchin S. purpuratus. A total of 8415 UniGenes were mapped to the non-redundant database. Salmon expression analysis revealed 725 significantly differentially expressed genes (DEGs) among CG, DG, and UG. These DEGs were enriched into 72 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, including a core set of immune correlated pathways notably in the phagosome, vitamin digestion and absorption, Wnt signaling, and Notch signaling pathways. DG was evidently upregulated in these immune pathways and could enhance phagocytosis directly or indirectly. Thus, phagocytosis was the main coelomic cellular immune response in S. intermedius challenged by spotting disease causative bacterium. The expression patterns of 10 DEGs were confirmed via RT-qPCR, and the expression levels were consistent with the results of RNA-seq. Furthermore, 9899 SSRs were identified, and 123,692, 151,827, and 114,368 candidate SNPs were identified from CG, DG, and UG, respectively. These results provide basic information for our understanding of sea urchin antibacterial immunity.

Effect of ceramic filler content on the mechanical and thermal behaviour of poly-L-lactic acid and poly-L-lactic-co-glycolic acid composites for medical applications

One main application of resorbable poly-L-lactic acid (PLLA) and poly-L-lactic-co-glycolic acid (PLGA) based materials is in medical implants. In this study composites were made from PLLA and PLGA with hydroxyapatite (HAp) respective beta-tricalcium phosphate (beta-TCP) fillers. The filler content and particle size were varied, and the thermal properties as well as the mechanical strength of the composites were investigated. The composites were made by an extrusion compounding process giving 2-2.5 mm diameter sized profiles. The results verified that the thermal stability of the composites was reasonable during the optimized compounding conditions. Scanning electron microscopy revealed that the fillers were well dispersed in the polymer matrices. The mechanical properties were improved by the addition of the fillers. The optimum mechanical properties for the extruded profiles were obtained with the HAp fillers. The E-modulus was increased from 3.3 to 4.6 GPa by addition of filler particles (30 wt%) whereas the flexural strength was reduced from 133 to 106 MPa.