RING-OPENING COPOLYMERIZATION OF DL-LACTIDE AND POLY(ETHYLENE GLYCOL) INITIATED BY LANTHANUM ACETATE AND APPLICATION OF THE COPOLYMER AS MATRIX OF MICROSPHERES CONTAINING VIBRIO CHOLERA ANTIGENS

Poly-dl-lactide-poly(ethylene glycol) (PELA) triblock copolymers were synthesized with lanthanum acetate as the initiator. PELA microspheres with entrapped Vibrio Cholera antigen and outer membrane protein (OMP) were prepared by a double emulsion W/O/W based on solvent extraction methods. The obtained microspheres showed smooth and spherical surface and their size varied between 0.5 and 5.0 mu m, which are suitable for oral targeting delivery system. The distribution tests in rabbits and mice through scanning electronic micrography and fluorescence microscope indicated that microspheres have successfully reached the immunization-related tissues, such as the liver, spleen and intestinal peyer's patches, following oral administration. The PELA microspheres were also evaluated as an efficient antigen delivery system by enhancing a higher protective ratio against live Vibrios Cholera.

Mitochondrial phylogenomics provides insights into the phylogeny and evolution of spiders(Arthropoda:Araneae)

Spiders are among the most varied terrestrial predators,with highly diverse morphology,ecology,and behavior.Morphological and molecular data have greatly contributed to advances in the phylogeny and evolutionary dynamics of spiders.Here,we performed comprehensive mitochondrial phylogenomics analysis on 78 mitochondrial genomes(mitogenomes)representing 29 families;of these,23 species from eight families were newly generated.Mesothelae retained the same gene arrangement as the arthropod ancestor(Limulus polyphemus),while Opisthothelae showed extensive rearrangement,with 12 rearrangement types in transfer RNAs(tRNAs)and control region.Most spider tRNAs were extremely truncated and lacked typical dihydrouridine or TΨC arms,showing high tRNA structural diversity;in particular,trnS1 exhibited anticodon diversity across the phylogeny.The evolutionary rates of mitochondrial genes were potentially associated with gene rearrangement or truncated tRNAs.Both mitogenomic sequences and rearrangements possessed phylogenetic characteristics,providing a robust backbone for spider phylogeny,as previously reported.The monophyly of suborder,infraorder,retrolateral tibial apophysis clade,and families(except for Pisauridae)was separately supported,and high-level relationships were resolved as(Mesothelae,(Mygalomorphae,(Entelegynae,(Synspermiata,Hypochilidae)))).The phylogenetic positions of several families were also resolved(e.g.,Eresidae,Oecobiidae and Titanoecidae).Two reconstructions of ancestral web type obtained almost identical results,indicating that the common ancestor of spiders likely foraged using a silk-lined burrow.This study,the largest mitochondrial phylogenomics analysis of spiders to date,highlights the usefulness of mitogenomic data not only for providing efficient phylogenetic signals for spider phylogeny,but also for characterizing trait diversification in spider evolution.