A Novel Method for Creating Heterologous Lethal Antibiotic Producers by Screening from Combi-OGAB Library with Various Promoters in a Biosynthetic Gene Cluster.

In this study, we devised a novel method to create heterologous producers of lethal antibiotics against host bacteria. Heterologous producers cannot be created when antibiotics are toxic to host bacteria. To overcome this challenge, we developed a novel method involving construction of a combinatorial library with various promoters and screening based on the production. To realize this, we utilized Combi-OGAB (Combinatorial Ordered Gene Assembly in Bacillus subtilis), which technology can effectively construct diverse combinatorial library and accelerate screening procedures. B. subtilis and Gramicidin S were selected as the host bacterium and the targeted antibiotic, respectively. The screened producer from Combi-OGAB screening cycles achieved >30-fold productivity over the lethal level. These results suggest that our strategy has the potential to maximize the phenotypic resistance of host bacteria to create heterologous lethal antibiotic producers.

Isolation and absolute configuration determination of aliphatic sulfates as the Daphnia kairomones inducing morphological defense of a phytoplankton-part 2.

4,8-Dimethylnonyl sulfate (1) and 3-methyl-4E-decenyl sulfate (2) were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802). The absolute configuration at C4 of 1 was determined by Ohrui's method applied to alcohol 3. The absolute stereochemistry at C3 of 2 was determined by (1)H-NMR analysis of the (R)-1NMA ester of alcohol 11.

Isolation of new aliphatic sulfates and sulfamate as the Daphnia Kairomones inducing morphological change of a phytoplankton Scenedesmus gutwinskii.

New aliphatic sulfates and sulfamates were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802). Their structures were determined by spectroscopic and synthetic studies.

Isolation and absolute configuration determination of aliphatic sulfates as the Daphnia kairomones inducing morphological defense of a phytoplankton.

2,6-Dimethylheptyl sulfate (1) and 6-methyloctyl sulfate (3) were isolated from Daphnia pulex as the Daphnia kairomones that induced morphological defense of a freshwater phytoplankton Scenedesmus gutwinskii var. heterospina (NIES-802). The absolute stereochemistry at C2 of 1 was determined by (1)H-NMR analysis of the (R)-MTPA ester of alcohol 2. The absolute configuration at C6 of 3 was determined by Ohrui's method applied to alcohol 4.