Possible occurrence of intracellular bacteria in Pseudonitzschia multiseries, a causative diatom of amnesic shellfish poisoning

Abstract

Polymerase chain reaction (PCR) products were obtained when the total RNA prepared from the axenically cultured cells of Pseudo-nitzschia multiseries was amplified by using primers that were designed from the 16S ribosomal RNA (rRNA) region of a bacterium isolated from the cells of Alexandrium tamarense, although the amount of the products was low. Some sequences of the PCR products were identical to those of bacteria that were isolated from the cultured medium of the original nonaxenic culture of Pseudo-nitzschia multiseries strain. These results suggest that P. multiseries possesses intracellular bacteria that originate from the environmental water.