Complete mitochondrial genome of Cultellus attenuatus and its phylogenetic implications

The complete mitochondrial genome of Cultellus attenuates, a new aquaculture species, was sequenced and compared with mitogenomes from seven species of Heterodonta bivalve mollusk in GenBank. The mitochondrial genome of C. attenuatus is 16888 bp in length and contains 36 genes, including 12 protein-coding genes, 2 ribosomal RNAs and 22 transfer RNAs, and all genes are encoded on the same strand. In comparison with C. attenuates, the mitochondrial genes of Sinonovacula constricta from the same family were not rearranged, but those of six other species from different families were rearranged to different degrees. The largest noncoding region of C. attenuatus is 1173 bp in length and has an A + T content of 68.24%, located between nad2 and trnK. The results of phylogenetic analysis show that C. attenuates and S. constricta belonging to Cultellidae cluster into one branch while two species of Solenidae (Solen grandis and Solen strictus) cluster as their sister taxa. In conclusion, we used the mitochondrial genome data to demonstrate the closest relationship between C. attenuatus and S. constricta in Heterodonta. These data not only contribute to the understanding of the phylogenetic relationship of Heterodonta but also serve as a resource for the development of genetic markers in aquaculture.

Complete mitochondrial genome of Cultellus attenuatus and its phylogenetic implications

The complete mitochondrial genome of Cultellus attenuates, a new aquaculture species, was sequenced and compared with mitogenomes from seven species of Heterodonta bivalve mollusk in the gene bank. The mitochondrial genome of C. attenuatus is 16888bp in length and contains 36 genes, including 12 protein-coding genes, 2 ribosomal RNAs and 22 transfer RNAs, and all genes are encoded on the same strand. In comparison with C. attenuates, the mitochondrial genes of the Sinonovacula constricta from the same family were not rearranged, but those of six other species from different family were rearranged to different degrees. The largest non-coding region of C. attenuatus is 1173bp in length and with the A + T content of 68.24%, located between nad2 and trnK. The results of phylogenetic analysis show that the C. attenuates and the S. constricta belonging to Cultellidae cluster into one branch while two species of Solenidae ( Solen grandis and Solen strictus) are clustering as their sister taxon. These data not only contribute to the understanding of the phylogenetic relationship of the Heterodonta, but also serve as a resource for the development of the genetic markers in aquaculture.

DNA barcoding of razor clam Solen spp. (Solinidae, Bivalva) in Indonesian beaches

Trisyani N, Rahayu DA. 2020. DNA barcoding of razor clam Solen spp. (Solinidae, Bivalva) in Indonesian beaches. Biodiversitas 21: 478-484. Solen spp. are shells with various morphological characteristics with a wide distribution of tropical and subtropical beaches, including Indonesia. The identification of Solen spp. is generally based on its morphological characteristics. This method is very problematic due to specimens share similarity in morphology and color. This study was using DNA barcode as a molecular identification tool. The bivalve COI sequence was amplified using PCR and molecular phylogenetic analysis using the Neighbor-Joining method. The amplified COI gene has a length of about 665 bp. The purpose of this study was to evaluate genetic variation and compare the phylogenetic Solen spp. in Indonesian waters. The composition of the nucleotide bases of Solen spp. the comparative species are A = 26.79%, C = 23.16%, G = 19.17% and T = 30.93%. The total nucleotide base A + T was 57.72%, while G + C was 42.33%. The results of phylogenetic analysis showed that Solen spp. Cirebon and Jambi are in one clade with Solen regularis with genetic distance 0.000 - 0.002. Solen spp. Surabaya, Bangkalan, Pamekasan, and Sumenep are in separate clades and are related to Solen grandis, Solen stricus and Solen lamarckii with genetic distance from 0.146 - 0.156. The diversity of nucleotide was 0.9780 and was divided into 12 haplotypes.

Structure and Identification of Solenin: A Novel Fibrous Protein from BivalveSolen grandisLigament

Fibrous proteins, which derived from natural sources, have been acting as templates for the production of new materials for decades, and most of them have been modified to improve mechanical performance. Insight into the structures of fibrous proteins is a key step for fabricating of bioinspired materials. Here, we revealed the microstructure of a novel fibrous protein: solenin fromSolen grandisligament and identified the protein by MALDI-TOF-TOF-MS and LC-MS-MS analyses. We found that the protein fiber has no hierarchical structure and is homologous to keratin type II cytoskeletal 1 and type I cytoskeletal 9-like, containing “SGGG,” “SYGSGGG,” “GS,” and “GSS” repeat sequences. Secondary structure analysis by FTIR shows that solenin is composed of 41.8%β-sheet, 16.2%β-turn, 26.5%α-helix, and 9.8% disordered structure. We believe that theβ-sheet structure and those repeat sequences which form “glycine loops” may give solenin excellence elastic and flexible properties to withstand tensile stress caused by repeating opening and closing of the shell valves in vivo. This paper contributes a novel fibrous protein for the protein materials world.