Atsushi Yamaguchi

Z-Lysine (ZLys) is a lysine derivative with a benzyloxycarbonyl group linked to the ε-nitrogen. It has been genetically encoded with the UAG stop codon, using the pair of an engineered variant of pyrrolysyl-tRNA synthetase (PylRS) and tRNA(Pyl). In the present study, we designed a novel Z-lysine derivative (AmAzZLys), which is doubly functionalized with amino and azido substituents at the meta positions of the benzyl moiety, and demonstrated its applicability for creating protein conjugates. AmA

Genetic code expansion has largely relied on two types of the tRNA-aminoacyl-tRNA synthetase pairs. One involves pyrrolysyl-tRNA synthetase (PylRS), which is used to incorporate various lysine derivatives into proteins. The widely used PylRS from Methanosarcinaceae comprises two distinct domains while the bacterial molecules consist of two separate polypeptides. The recently identified PylRS from <i>Candidatus</i> Methanomethylophilus alvus (CMaPylRS) is a single-domain, one-polypeptide enzyme t

Diel and seasonal vertical distribution, life cycle and body allometry of Pleuromamma scutullata and Heterorhabdus tanneri were investigated in the Oyashio region during September 1996 through October 1997. Monthly samples were collected with 0.1 mm mesh closing nets towed through five discrete depths between the surface and 2000 m. Copepodite stages 1 through 6 of P.scutullata and 3 through 6 of H.tanneri were collected effectively with the nets. Day-night samplings during December 1996, April

Population structure and life cycle of Pseudocalanus minutus and P. newmani in Toyama Bay, southern Japan Sea, were investigated based on seasonal samples obtained by vertical hauls (0-500 m depth) of twin-type Norpac nets (0.33-mm and 0.10-mm mesh) over one full year from February 1990 through January 1991. Closing PCP nets (0.06-mm mesh) were also towed to evaluate vertical distribution patterns in September 1990, November 1991 and February 1997. P. minutus was present throughout the year. The

Indeep water, most of the calanoid copepod community consisted of cosmopolitan species, while an endemiccommunity was observed in the subarctic region. Because the food of deep-sea calanoid copepods originates fromthe surface layer, sufficient and excess flux in the eutrophic subarctic region may be responsible for maintaining the endemic species in the region.

As habitats of pelagic copepods, epipelagic oceanic environments are characterized by greater food availability but higher risks of predation. Both food supply and predation risk rapidly drop with increasing depth. We studied day/night vertical distribution patterns of copepodid stages of 6 epipelagic (Neocalanus cristatus, N. flemingeri, N. plumchrus, Eucalanus bungii, Metridia pacifica, and M. okhotensis), 2 mesopelagic (Gaetanus simplex and Pleuromamma scutullata), and 6 bathypelagic copepods