Seasonal dynamics of the fish parasite Neoplagioporus ayu (Digenea) in its definitive host, Plecoglossus altivelis, in the Chikugo River, Kyushu, Japan

Seasonal dynamics of the fish parasite Neoplagioporus ayu (Digenea; Opecoelidae; Plagioporinae) in its definitive host, the ayu Plecoglossus altivelis, in the Chikugo River, Kyushu, Japan, was examined. Natural ayu are amphidromous. In the upper Chikugo River, ayu fry raised in hatcheries are released into the river every spring because the migration of ayu is completely blocked by a dam that has no fish-pass channel. Ayu collected in April 2003 (within 1 month after release) harbored no N. ayu, but the prevalence of N. ayu rose to about 80% in May. The prevalence, abundance, and maturity of N. ayu were maintained at high levels from June to September. These finding indicate that the life cycle of N. ayu is completed in a freshwater area, although its intermediate hosts have not yet been identified despite the intense examination of invertebrates.     

Promoting effect of wood vinegar compounds on fruit-body formation ofPleurotus ostreatus

The promoting effect of wood vinegar compounds on the fruiting ofPleurotus ostreatus (Japanese name, Hiratake) was investigated. Not only crude wood vinegar but its components, 3,5-dimethylphenol, 2-methoxyphenol, butanoic acid and 1-pentanol, had the ability to promote fruit-body formation on liquid medium. For use of these promoters industrially, a test for practical cultivation was carried out using a commercial sawdust medium. The addition of 100 µg/ml butanoic acid and 100 µg/ml 2-methoxyphenol into the sawdust medium after removal of the surface mycelial layer (kinkaki in Japanese) produced 29 and 23% higher yields of fruit-bodies than the control cultures (137.2 g/bottle), respectively. The addition of the crude wood vinegar as a medium component into sawdust substrates in the concentration range of 0.1–6% increased yields of fruit-bodies by 21–42% over the control.