RESUMO
Genetic diversity of oysters Crassostrea belcheri (Sowerby, 1871), C. iredalei (Faustino, 1932), Saccostrea cucullata (Born, 1778), S. forskali (Gmelin, 1791), and Striostrea (Parastriostrea) mytiloides (Lamarck, 1819) (Ostreoida, Mollusca) was analyzed by polymerase chain reaction - restriction fragment length polymorphism (PCR-RFLP) of 16S ribosomal DNA with AcsI, AluI, DdeI, DraI, RsaI, and TaqI, 18S ribosomal DNA with HinfI, and cytochrome oxidase subunit I with AcsI, DdeI and MboI. A total of 54 composite haplotypes were observed. Species-diagnostic markers were specifically found in C. belcheri, C. iredalei, and S. cucullata, but not in S. forskali and Striostrea mytiloides, which shared common composite haplotypes. Neighbor-joining trees constructed from genetic distances between pairs of composite haplotypes and species indicated large genetic differences between Crassostrea and Saccostrea (including Striostrea mytiloides), but closer relationships were observed within each genus. Four groups of unidentified oysters (Crassostrea sp. and Saccostrea sp. groups 1, 2, and 3) were also genetically analyzed. Fixed RFLP markers were found in Crassostrea sp. and Saccostrea sp. group 2, but not in Saccostrea sp. groups 1 and 3. Phylogenetic and genetic heterogeneity analyses indicated that Crassostrea sp. and Saccostrea sp. group 2 should be considered as newly unidentified oyster species in Thailand.
Assuntos
Bivalves/genética , Variação Genética , Filogenia , Polimorfismo Genético , Animais , Análise por Conglomerados , Primers do DNA , DNA Mitocondrial/genética , Geografia , Haplótipos/genética , RNA Ribossômico/genética , Mapeamento por Restrição , Especificidade da Espécie , TailândiaRESUMO
Genetic diversity of abalone in Thailand, Haliotis asinina, H. ovina, and H. varia, was analyzed by polymerase chain reaction (PCR) of 18S and 16S rDNAs, with randomly amplified polymorphic DNA (RAPD) and restriction fragment length polymorphism (RFLP). Species-specific RAPD markers were found in each abalone species. Restriction analysis of 18S (nuclear) ribosomal DNA with Alu I, Taq I, and Hae III and 16S (mitochondrial) rDNA with Bam HI, Eco RI, Hae III, and Alu I gave 12 and 13 digestion patterns, respectively. A total of 49 composite haplotypes were found. A dendogram obtained by the unweighted pair-group method with arithmetic mean, constructed from divergence between pairs of composite haplotypes, revealed reproductively isolated gene pools of these abalone and indicated that H. asinina and H. ovina are genetically closer than H. varia. When H. varia was discovered owing to small sample sizes, geographic heterogeneity analysis and FST estimate indicated clear genetic differentiation between H. ovina originating from the Andaman Sea (west) and the Gulf of Thailand (east, P<0.0001), whereas partial differentiation was observed between the Philippines and the remaining H. asinina samples (P<0.0021). The amplified 16S rDNAs of individuals representing composite haplotypes found in this study were cloned and sequenced. A neighbor-joining tree constructed from sequence divergence of 16S rDNA accurately allocated those sequences according to species origins of abalone. Species-specific PCR based on 16S rDNA polymorphism was successfully developed in H. asinina and H. varia but not in H. ovina.
Assuntos
Variação Genética , Moluscos/genética , Filogenia , Animais , Sequência de Bases , Análise por Conglomerados , DNA Ribossômico/genética , Eletroforese em Gel de Ágar , Geografia , Haplótipos/genética , Dados de Sequência Molecular , Polimorfismo de Fragmento de Restrição , Técnica de Amplificação ao Acaso de DNA Polimórfico , Alinhamento de Sequência , Análise de Sequência de DNA , TailândiaRESUMO
Molecular genetic keys for identification of 3 commercially cultured oysters (Crassostrea belcheri, Crassostrea iredalei, and Saccostrea cucullata) in Thailand were developed based on restriction analysis of 18S ribosomal DNA and cytochrome oxidase subunit I (COI). Digestion of the amplified 18S rDNA with Hinf I unambiguously differentiated Crassostrea oysters from Saccostrea oysters and Striostrea (Parastriostrea) mytiloides. In addition, species-specific restriction fragment length polymorphism patterns of C. belcheri, C. iredalei, and S. cucullata were consistently observed when the gel-eluted COI was digested with Mbo I and Dde I. Thirty composite haplotypes were observed across all individuals. Species-specific composite haplotypes were found in C. belcheri (AAAA and AAAB), C. iredalei (AABC and AABU), and S. cucullata (BBCD and BBCE), respectively. The most common composite haplotype of COI in C. belcheri (AAAA), C. iredalei (AABC), and S. cucullata (BBCD) was amplified, cloned, and sequenced. Detection of C. belcheri and C. iredalei based on polymerase chain reaction was further developed using more specific primers (HCO2198 and R372) followed by digestion of a 372-bp product with Mbo I.
Assuntos
DNA Ribossômico/genética , Complexo IV da Cadeia de Transporte de Elétrons/genética , Haplótipos/genética , Ostreidae/genética , Filogenia , Animais , Sequência de Bases , Dados de Sequência Molecular , Ostreidae/classificação , Polimorfismo de Fragmento de Restrição , Subunidades Proteicas/genética , Mapeamento por Restrição , Especificidade da Espécie , TailândiaRESUMO
Tridacnin, a glycoprotein lectin, was isolated from the symbiotic marine clam Hippopus hippopus and the structure of its major N-glycan chains determined. Tridacnin contains only N-linked glycans which were quantitatively cleaved by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. Following purification by anion-exchange HPLC, the structures of the oligosaccharides were established using a combination of electrospray ionisation mass spectrometry, 1H-NMR spectroscopy and linkage analysis. The N-glycans are primarily of the oligomannose type but, in addition, some contain a novel 6-O-Me group on the terminal mannose residue of the chain. The N-glycan chains had the following structures. [formula: see text]
