Proteomic Analysis of the Spineless Cuttlefish Sepiella Japonica: Exploratory Analyses on the Phenomenon of Death after Spawning

Senescence and death occur after the spawn of female cuttlefish, which results in an immense loss of reproductive resources. To better understand the physiological mechanisms involving death after spawning in Sepiella japonica (Japanese spineless cuttlefish). We used proteomic methods to identify differentially expressed proteins (DEPs) in the optic glands of S. japonica at three distinct growth stages: pre-spawning after sexual maturity (group A); spawning (group B) and post-spawning before death (group C). About 955, 1000, and 1024 DEPs were identified for each comparative group analysis (i.e. group B vs A, group B vs C, and group C vs A). The gene ontology (GO) analysis showed that the function of DEPs was correlated with peptidase activity, metal-ion binding and structural molecule activity, and the majority of DEPs were involved in signal transduction and energy metabolism. It was also identified some aging-related pathways in the results of KEGG annotation. Based on previous studies of anti-aging effects in cephalopods, our study provides a new insights about the death of S. japonica after spawning at the protein level.

MicroRNA expression profiles of the cuttlefish (Sepiella japonica) during embryonic development

The Japanese spineless cuttlefish (Sepiella japonica) is an important economic species and model animal. Many studies suggested that microRNAs (miRNAs) play an important regulatory role in the embryonic development of this species. However, comparative miRNA profiles during embryogenesis of cuttlefish have not been reported before. Therefore, in this study, miRNA profiles were obtained from embryos of S. japonica from eye primordium formation to larval growing stage by miRNA sequencing. A total of 1528 known miRNAs and 203 novel miRNAs were identified during different development stages. Among which, 62 differentially expressed miRNAs among different development stages were identified. GO analysis indicated that the potential target genes for these differentially expressed miRNAs were involved in many GO terms including intracellular membrane-bounded organelle, cell morphogenesis, regulation of developmental process, etc. In addition, miRNA-mRNA network analysis indicated that many of the target genes of these differentially expressed miRNAs were involved in integral component of the membrane. In conclusion, our work provided a global view of miRNA expression profiles during embryonic development of S. japonica.

Multiple paternity assessed in the cuttlefish Sepiella japonica (Mollusca, Cephalopoda) using microsatellite markers

Multiple paternity was demonstrated for seven clutches of eggs and 40 offspring sampled from these clutches in the cuttlefish Sepiella japonica from Fujian Shacheng Harbor Cultivation Base (Fujian Province, China), using four microsatellite DNA markers. It was observed that female cuttlefish copulated with different males. In this study, genotyping data suggest that at least three paternal allele genotypes were present in all seven clutches indicating that at least two males were responsible for each brood. Combined with behavioral observations, this study provides evidence for sperm competition and multiple paternity in S. japonica.