Screening bacterial metabolites for inhibitory effects against Batrachochytrium dendrobatidis using a spectrophotometric assay.
Dis Aquat Organ
; 103(1): 77-85, 2013 Mar 13.
Article
in En
| MEDLINE
| ID: mdl-23482387
ABSTRACT
Certain bacteria present on frog skin can prevent infection by the pathogenic fungus Batrachochytrium dendrobatidis (Bd), conferring disease resistance. Previous studies have used agar-based in vitro challenge assays to screen bacteria for Bd-inhibitory activity and to identify candidates for bacterial supplementation trials. However, agar-based assays can be difficult to set up and to replicate reliably. To overcome these difficulties, we developed a semi-quantitative spectrophotometric challenge assay technique. Cell-free supernatants were prepared from filtered bacterial cultures and added to 96-well plates in replicated wells containing Bd zoospores suspended in tryptone-gelatin hydrolysate-lactose (TGhL) broth medium. Plates were then read daily on a spectrophotometer until positive controls reached maximum growth in order to determine growth curves for Bd. We tested the technique by screening skin bacteria from the Australian green-eyed tree frog Litoria serrata. Of bacteria tested, 31% showed some degree of Bd inhibition, while some may have promoted Bd growth, a previously unknown effect. Our cell-free supernatant challenge assay technique is an effective in vitro method for screening bacterial isolates for strong Bd-inhibitory activity. It contributes to the expanding field of bioaugmentation research, which could play a significant role in mitigating the effects of chytridiomycosis on amphibians around the world.
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Ranidae
/
Bacteria
/
Chytridiomycota
/
Antifungal Agents
Type of study:
Diagnostic_studies
/
Screening_studies
Limits:
Animals
Language:
En
Journal:
Dis Aquat Organ
Journal subject:
BIOLOGIA
/
MEDICINA VETERINARIA
/
MICROBIOLOGIA
Year:
2013
Document type:
Article
Affiliation country: