Reproductive farming technology in Japanese eel and chub mackerel

Japanese eel(Anguilla japonica)and chub mackerel(Scomber japonicus)are commercially valuable species in Asian aquaculture.The reduction in eel and chub mackerel resources has been a serious problem in recent years that should be addressed by reducing the catch of their natural populations to halt their decline and reach the Sustainable Development Goals.Furthermore,securing sufficient food supply by aquaculture is an important step in addressing the increasing demand for fish products in recent years.Traditionally,juveniles of the Japanese eel and chub mackerel have been captured to be raised in aquaculture.Owing to the extensive research on these species,new technologies have been developed for full-lifecycle aquaculture of Japanese eel in 2011 and chub mackerel in 2014.These technologies are expected to stop the decline of natural resources and provide a stable food supply.Recently,seed production of these species has increased owing to the development of successful broodstock management and larval rearing techniques.Fundamental information on oocyte maturation and ovulation and its application for artificial induction of sexual maturation is needed to produce good quality seeds of the Japanese eel and chub mackerel.Here,hormonal mechanisms and previously and newly developed methods for artificial seed production have been described.

Synthetically engineered microbes reveal interesting principles of cooperation

Cooperation is ubiquitous in biological sys- tems. However, if natural selection favors traits that confer an advantage to one individual over another, then helping others would be paradoxical. Nevertheless, cooperation persists and is critical in maintaining homeostasis in systems ranging from populations of bacteria to groupings of mammals. Developing an understanding of the dynamics and mechanisms by which cooperation operates is critical in understanding ecological and evolutionary relationships. Over the past decade, synthetic biology has emerged as a powerful tool to study social dynamics. By engineering rationally controlled and modulatable beha- vior into microbes, we have increased our overall under- standing of how cooperation enhances, or conversely constrains, populations. Furthermore, it has increased our understanding of how cooperation is maintained within populations, which may provide a useful framework to influence populations by altering cooperation. As many bacterial pathogens require cooperation to infect the host and survive, the principles developed using synthetic biology offer promise of developing novel tools and strategies to treat infections, which may reduce the use of antimicrobial agents. Overall, the use of engineered cooperative microbes has allowed the field to verify existing, and develop novel, theories that may govern cooperative behaviors at all levels of biology.