Iron Fertilization Can Enhance the Mass Production of Copepod, , for Fish Aquaculture.

Copepods are proven nutritious food sources for the mariculture/larviculture industry, however, unreliable methods for mass production of copepods are a major bottleneck. In this study, we modified a previously reported inorganic fertilization method (N: 700 μg L and P: 100 μg L) by the addition of iron (Fe: 10 μg L, using FeSO·7HO) (+Fe treatment) and compared its suitability for copepod culture () to the original method (control). The experiment was conducted outdoors in 1000 L tanks for 15 days.

The Advantages of Inorganic Fertilization for the Mass Production of Copepods as Food for Fish Larvae in Aquaculture.

Copepods are commonly used as live feed for cultured fish larvae, but the current mass production method using organic fertilizers cannot meet the market demand for copepods. We evaluated the feasibility of applying an inorganic fertilization method, which is currently in use in freshwater and marine larviculture, to the mass production of copepods. For 30 days, and with five replicates of each treatment, we made comparative daily measurements of various parameters of (1) copepod cultures fertilized with commercially available condensed fish solubles (organic fertilization) and (2) other cultures in which the concentration of inorganic phosphorus was maintained at 100 μg P L and that of inorganic nitrogen at 700 μg N L (inorganic fertilization).

Cell-Based Biosensor with Dual Signal Outputs for Simultaneous Quantification of Phenylacetic Acid and Phenylethylamine.

Despite the importance of 2-phenylacetic acid, a plant hormone in the endogenous auxin family, its biosynthesis pathway has yet to be elucidated. In this study, we developed a novel whole-cell biosensor for the simultaneous quantification of 2-phenylacetic acid (PA) and 2-phenylethylamine (PEA) through the regulation of bacterial catabolism of aromatic compounds. We used the PA regulon to enable the recognition of PA and PEA.

Determination of Gold Ions in Human Urine Using Genetically Engineered Microorganisms on a Paper Device.

This paper presents a whole-cell biosensor that operates in conjunction with a smartphone-based fluorescence diagnostic system on a paper device to monitor the concentration of gold ions in human urine. The heavy metal-tolerant bacteria Cupriavidus metallidurans was genetically engineered for use as a chassis in a red fluorescent protein (RFP)-based microbial sensor. The biosensor is highly sensitive to gold ions, with a detection limit of 110 nM.