Common otolith microstructure related to key early life-history events in flatfishes identified in the larvae and juveniles of cresthead flounder Pseudopleuronectes schrenki.

Otolith microstructure of reared and wild cresthead flounder Pseudopleuronectes schrenki larvae and juveniles was used to investigate the daily periodicity of ring formation, morphological change and unique otolith structure related to important life events. By comparing microstructural features of P. schrenki with those reported for other flatfish species, it was shown that there may be microstructural features that are common to all flatfishes. In the sagittae and lapillus, a check (a distinct ring) was formed in the centre of otoliths at c. 6 days post hatching, and the daily formation of rings observed outside the check was confirmed. During metamorphosis, accessory primordia (AP) of otolith growth were formed on the outer edge of the sagittae, and the shape of the sagittae became more complex. No AP was formed on the lapilli, however, and otolith rings were concentrically formed throughout the larval and juvenile (≤51·6 mm standard length, LS ) stages. It is proposed, therefore, that lapilli are more appropriate than sagittae for analysis throughout the larval and juvenile (≤51·6 mm LS ) stages. During metamorphosis, unique rings that are relatively wide and show weak contrast are formed on lapilli (metamorphosing zone, MZ). Hence, the duration of metamorphosis, larval duration and the days of juvenile life can be estimated by the number of rings within the MZ, using rings from the check to outermost ring of the MZ, and that of rings formed outside MZ, respectively. The formation of AP on sagittae as well as the absence of AP, bilateral asymmetry and the formation of a unique structure during metamorphosis on lapilli have also been reported for other flatfishes.

Anti-herpes virus activity of Solanum steroidal glycosides.

Since some Solanum-genus plants have traditionally been used for anti-cancer and anti-herpes agents from olden times, we examined anti-herpes simplex virus type 1 (HSV-1) activity of typical steroidal glycosides with the frameworks of spirostane (including nuatigenin glycoside), furostane, solasodane, tomatidane and ergostane (including dimer) obtained from Solanum plants. Among these steroidal glycosides, the spirostanol glycosides were most effective. An inclination was observed for the potency of activity to decrease in the order of spirostane, tomatidane, ergostane, solasodane, nuatigenin type, dimer of ergostane and furostane. It was also suggested that the activity depends on the kind of oligosacchride moiety.