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Objectives: To clarify the underlying molecular mechanism of corticosterone methyl oxidase type II (CMO II) deficiency, Japanese patients newly diagnosed with CMO II deficiency were investigated. Methods: We analyzed the patients’ genomic DNA sequence on all 9 exons of the CYP11B2 gene. In addition, restriction fragment length polymorphism (RFLP) analysis and expression studies were performed. Results: The analysis showed that the patients homozygously retained a missense mutation, GGC[⁴³⁵Gly]→AGC[Ser], in the CYP11B2 gene. Expression studies indicated that the steroid 18-hydroxylase/oxidase activities of the mutant enzyme were substantially reduced. Conclusion: These results support the hypothesis that this mutation causes CMO II deficiency in the patients, and are in accordance with our theory that the partial loss of P-450_C18 activities causes CMO II deficiency.

Tetrodotoxin (TTX) is a potent toxin but it could be used in pharmaceutical field. Identification of TTX producing bacteria in pufferfish is necessary for TTX yield and the pufferfish conservation. In this study, Lagocephalus was collected from Cam Ranh Sea, a central part of Vietnam during spring season. The liver and intestine were incubated in 0.9 % NaCl for TTX detection in pufferfish. To be benefited from the isolation of new TTX producing bacteria, the liver and intestine were incubated in 6.5 % NaCl. The cultures were used to test the toxin and to isolate the bacterial community that could yield TTX. Surprisingly, Providencia rettgeri T892 in intestine could produce TTX identified by biochemical test and 16S rRNA sequencing. This strain was used to test the production of TTX, based on thin layer chromatography (TLC), mouse bioassay and high performance liquid chromatography (HPLC) analysis. The bacterium was optimized for TTX production in media prepared from the meat-washing water of Auxis thazard, Megalaspis cordyla and Decapterus maruadsi. Interestingly, the TTX obtained 0.106 mg/mL and 0.055 mg/mL in medium prepared from A. thazard and M. cordyla, respectively while there was no TTX production detected in medium prepared from D. maruadsi. This paper could contribute to warn to the human health care system about a possible TTX poisoning in some cases related to eating fishes.