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Both ZeBrafish (ZB), a recently identified DNA transposon in the zebrafish genome, and SB, a reconstructed transposon originally discovered in several fish species, are known to exhibit high transposition activity in vertebrate cells. Although a similar structural organization was observed for ZB and SB transposons, the evolutionary profiles of their homologs in various species remain unknown. In the present study, we compared their taxonomic ranges, structural arrangements, sequence identities, evolution dynamics, and horizontal transfer occurrences in vertebrates. In total, 629 ZB and 366 SB homologs were obtained and classified into four distinct clades, named ZB, ZB-like, SB, and SB-like. They displayed narrow taxonomic distributions in eukaryotes, and were mostly found in vertebrates, Actinopterygii in particular tended to be the major reservoir hosts of these transposons. Similar structural features and high sequence identities were observed for transposons and transposase, notably homologous to the SB and ZB elements. The genomic sequences that flank the ZB and SB transposons in the genomes revealed highly conserved integration profiles with strong preferential integration into AT repeats. Both SB and ZB transposons experienced horizontal transfer (HT) events, which were most common in Actinopterygii. Our current study helps to increase our understanding of the evolutionary properties and histories of SB and ZB transposon families in animals. [ABSTRACT FROM AUTHOR]

General anesthetics can cause neurological damage and long-term behavioral/cognitive impairment during fetal and early postnatal life. However, the adverse influence on embryo development induced by propofol is unclear. We used embryonic zebrafish to explore the effects of propofol on embryonic and larval growth and development, and the related apoptotic mechanism. Zebrafish embryos were immersed in propofol (1, 2, 3, 4, and 5 μg/ml) dissolved in E3 medium from 6 to 48 hours post fertilization (hpf). The survival rate, locomotion, heart rate, hatchability, deformity rate, and body length were analyzed at defined stages. Terminal deoxynucleotidyl transferase nick-end-labeling was used to detect zebrafish embryo apoptosis, and the expression levels of apoptosis-related genes were determined using quantitative real-time reverse transcription PCR and whole-mount in situ hybridization. Larvae at 48 hpf were anesthetized by immersion in E3 culture medium containing 2 μg/ml propofol, the reasonable anesthetic concentration for zebrafish embryos, which caused significant caudal fin dysplasia, light pigmentation, edema, hemorrhage, and spinal deformity, and decreased the hatchability, body length, and heart rate. The numbers of apoptotic cells in propofol-treated 12, 48 and 72 hpf embryos increased significantly, and the mRNA expression levels of intrinsic apoptosis pathway-related casp3a, casp3b, casp9, and baxb genes were upregulated, mainly in the head and tail. Propofol decreased apoptosis in the head and back of 24 hpf zebrafish, which was consistent with the mRNA expression analysis. Our findings demonstrated that zebrafish embryos and larvae exposed to propofol experienced developmental toxicity, which correlated with the intrinsic apoptosis pathway with casp3a, casp3b, casp9, and baxb as the key genes. [ABSTRACT FROM AUTHOR]