RESUMEN
Six isolates were recovered from great scallop (Pecten maximus) broodstock in a hatchery in Bergen, Norway. The strains were thoroughly characterized by a polyphasic approach. Phylogenetic analysis based on 16S rRNA gene sequences indicated that these strains are related to the genus Sinobacterium, showing sequence similarities between 96.97 and 97.63 % with the only species of the genus, Sinobacterium caligoides. Phenotypic characterization showed that the strains are typical marine halophiles, Gram negative, aerobic chemoorganotrophs, and allowed their differentiation from the closely related taxa. The G+C content of the novel strains was 52.2 ± 1 mol% and the predominant fatty acids were C16:0, C16:1 ω7c/C16:1 ω6c and C18:1 ω7c. The value for DNA-DNA relatedness between strain 3CM4(T) and the S. caligoides type strain LMG 25705(T) was 46â %. Hybridization values between strain 3CM4(T) and the other scallop isolates ranged from 82 to 93.6 %. Based on all data collected, the six scallop strains represent a novel species of the genus Sinobacterium, for which the name Sinobacterium norvegicum sp. nov., is proposed with strain 3CM4(T) (=CECT 8267(T); =CAIM 1884(T)) as type strain.
Asunto(s)
Gammaproteobacteria/clasificación , Gammaproteobacteria/aislamiento & purificación , Pecten/microbiología , Aerobiosis , Animales , Técnicas de Tipificación Bacteriana , Composición de Base , Análisis por Conglomerados , Citosol/química , ADN Bacteriano/química , ADN Bacteriano/genética , ADN Ribosómico/química , ADN Ribosómico/genética , Ácidos Grasos/análisis , Gammaproteobacteria/genética , Gammaproteobacteria/fisiología , Microscopía Electrónica de Rastreo , Datos de Secuencia Molecular , Noruega , Hibridación de Ácido Nucleico , Filogenia , ARN Ribosómico 16S/genética , Análisis de Secuencia de ADNRESUMEN
Cell density and fatty acid (FA) content of Pavlova lutheri and Chaetoceros muelleri were analysed in a continuous algal production system (250-L bags) with reduced diameter. The cell density and FA content and composition in the algal production system were determined in replicate bags over a period of 5 weeks. The results showed that the cell density and essential FAs increased during the experiment for both species. After 5 weeks the mean cell numbers had increased to 6.0 ± 0.3 × 10(6) cells mL(-1) in the P. lutheri bags and 6.0 ± 0.4 × 10(6) cells mL(-1) in the C. muelleri bags. The content of total FAs increased significantly (p < 0.05) in all of the bags during the experiment. At the end of the experiment the mean total FA content were 2.7 ± 0.3 pg cell(-1) in the P. lutheri bags and 1.8 ± 0.1 pg cell(-1) in the C. muelleri bags. Maximum total FA content registered was 3.0 pg cell(-1) in one of the P. lutheri bags. The content of the essential FAs (ARA, EPA, DHA) increased over time in both of the species. At the end of the experiment the content of EPA (0.6 ± 0.1 pg cell(-1)) and DHA (0.3 ± 0.0 pg cell(-1)) were highest in the P. lutheri bags, while ARA (0.1 ± 0.0 pg cell(-1)) was highest in C. muelleri. EPA and DHA constituted 22% and 11%, respectively, of total FA content in P. lutheri, while ARA constituted 6% of total FA content in C. muelleri. The results from this experiment indicate that flagellates such as P. lutheri perform better in narrow bags with improved light conditions, while diatoms like C. muelleri perform better in wider bags under light limitation. Implications for bivalve hatcheries are discussed. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10811-011-9655-6) contains supplementary material, which is available to authorized users.