Effects of HSP70 chaperones Ssa1 and Ssa2 on Ste5 scaffold and the mating mitogen-activated protein kinase (MAPK) pathway in Saccharomyces cerevisiae.

Ste5 is a prototype of scaffold proteins that regulate activation of mitogen-activated protein kinase (MAPK) cascades in all eukaryotes. Ste5 associates with many proteins including Gβγ (Ste4), Ste11 MAPKKK, Ste7 MAPKK, Fus3 and Kss1 MAPKs, Bem1, Cdc24. Here we show that Ste5 also associates with heat shock protein 70 chaperone (Hsp70) Ssa1 and that Ssa1 and its ortholog Ssa2 are together important for Ste5 function and efficient mating responses.

In vitro cultivation of early schistosomula of nasal and visceral bird schistosomes (Trichobilharzia spp., Schistosomatidae).

Cercariae of bird schistosomes (Trichobilharzia szidati and Trichobilharzia regenti) were mechanically stimulated to transform to schistosomula and kept in different cultivation media supplemented with duck red blood cells and/or homogenized nervous tissue. The development under in vitro conditions was compared with that in vivo, using the following characters: emptying of penetration glands, surface changes, food uptake, and growth of early schistosomula. The results show that the cultivation medium routinely used for human schistosomes is also suitable for mass production of early schistosomula of bird schistosomes, including the unique nasal species-T.