Isolation and Biological Activity of Toxins Produced by a Japanese Strain of Pseudomonas tolaasii, the Pathogen of Bacterial Rot of Cultivated Oyster Mushroom.

Proposal of Mycetocola gen. nov. in the family Microbacteriaceae and three new species, Mycetocola saprophilus sp. nov., Mycetocola tolaasinivorans sp. nov. and Mycetocola lacteus sp. nov., isolated from cultivated mushroom, Pleurotus ostreatus.

“…Micro-organisms isolated from rotting Pleurotus ostreatus fruiting bodies were cultured on PS agar medium containing 0n5 g Ca(NO $ ) # ; 4H # O, 2 g Na # HPO % ; 12H # O, 5 g peptone, 15 g sucrose and 15 g agar in 1 l of a decoction of 300 g potato tuber slices (pH 7n0) as described by Wakimoto (1955). Ten strains were selected as tolaasins-detoxifying strains by using the potato tuber slice method (Shirata et al, 1995) (Table 1). All strains were cultured aerobically at 28 mC in a peptone\yeast extract medium (PY medium) containing 10 g peptone, 2 g yeast extract, 2 g NaCl and 2 g -glucose in 1 l H # O (pH 7n2).…”

“…Pseudomonas tolaasii Paine produces pathogenic extracellular toxins, tolaasins (Nutkins et al, 1991 ;Shirata et al, 1995), and causes brown blotch disease in economically important cultivated mushrooms Pleurotus ostreatus Kummer and Agaricus bisporus The DDBJ accession numbers for the 16S rRNA gene sequences of strains CM-01 T , CM-05 T and CM-10 T are AB012647, AB012646 and AB012648, respectively.…”

Identification of Non-Pseudomonad Bacteria from Fruit Bodies of Wild Agaricales Fungi That Detoxify Tolaasin Produced byPseudomonas tolaasii

“…1). 8,9) Bacterial strains that suppressed the occurrence of blackening were scored as tolaasin-detoxifying agents (Fig. 1).…”

“…[1][2][3] The bacterium produces tolaasin, an extracellular lipodepsipeptide toxin needed for the elicitation of the disease symptoms. [4][5][6][7][8] We previously reported that a Gram-positive bacterium, which was then not assigned to any deˆned bacterial genera, from rotted fruit bodies of cultivated P. ostreatus detoxiˆed tolaasin and suppressed disease development on P. ostreatus and A. bisporus under our laboratory assay conditions. 9) The following intensive systematic analysis showed that this bacterium was a new member of the family Microbacteriaceae, and allowed us to propose a new genus, Mycetocola, and to assign the bacterium to Mycetocola tolaasinivorans.…”

Isolation of the Bacterium Pseudomonas sp. HC1 Effective in Inactivation of Tolaasin Produced by Pseudomonas tolaasii

“…tolaasii는 tolaasin이라는 독소를 생산하여 세포 밖으 로 분비하는데, tolaasin은 아미노산 18개로 구성된 분자량 1,985 Da의 lipodepsipeptide로, N-말단이 β-hydoxyoctanoic acid와 acylation되어 있으며, C-말단의 lysine은 14번 째의 threonine과 lactone을 형성하여 환상결합을 하고 있 는 2차 대사산물임이 밝혀졌다 (Nutkins et al, 1991;Jourdan et al, 2003). 이 독소는 버섯 세포막에 유입되어 이온 통로 형성과 물질이동 및 이에 따른 세포내 삼투압의 교란 을 통한 세포막의 파괴, 조직의 괴사 등의 과정을 통하여 갈색무늬병을 일으키는 것으로 알려져 있으며 Cho and Kim, 2003) P. tolaasii가 병을 일으키는데 필요한 가장 중요한 병원성 결정 인자로 보고되었다 Nair and Fahy, 1973; (Shirata et al, 1995). 독소 저해균의 선발은 동결건조된 tolaasin powder를 30%(w/v) 로 희석하여 분리된 미생물과 1:1로 혼합하여 감자조각 위 에 50 µl씩 접종하여 25 o C 항온기에 보관하면서 갈변정도 를 조사하여 독소저해균을 선발하였다 (Murata and Magae, 1996;Tsukamoto et al, 1998).…”