ChemInform Abstract: Burkholdines 1097 and 1229, Potent Antifungal Peptides from Burkholderia ambifaria 2.2N.

Tawfik, Kamilia A.; Jeffs, Peter W.; Bray, Brian L.; Dubay, George R.; Falkinham, Joseph O. Iii; Mesbah, Mostafa K.; Youssef, Diaa T. A.; Khalifa, Sherief; Schmidt, Eric W.

doi:10.1002/chin.201027180

Cited by 10 publications

(24 citation statements)

References 1 publication

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“…), cyclic lipopeptides (so‐called burkholdines; Tawfik et al . ), pyrrolnitrin, phenazine (Cartwright, Chilton & Benson ), 4‐quinolinones (Moon et al . ), 2‐hydroxymethyl‐chroman‐4‐one (Kang et al .…”

Section: Discussionmentioning

confidence: 99%

Distance‐dependent effects of pathogenic fungi on seedlings of a legume tree: impaired nodule formation and identification of antagonistic rhizosphere bacteria

Liu

Xie

et al. 2016

Journal of Ecology

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1. The Janzen-Connell (JC) hypothesis proposes that diversity of tree communities is promoted by species-specific enemies that suppress seedling recruitment. Pathogenic soil-borne fungi are often responsible for JC effects. However, previous ecological studies have not placed JC effects in the context of beneficial soil bacteria. Using the JC effect surrounding a subtropical legume tree (Ormosia glaberrima) as a model, we characterized tripartite interactions between seedlings, soil fungi and plant-associated bacteria. 2. Survival of seedlings grown in soil inocula collected at close distances to focal adult trees was reduced. Half of the experimental units were treated with fungicides to confirm the presence of pathogenic fungi. In a parallel experiment, nitrogen-fixing rhizobia induced fewer nodules on O. glaberrima seedlings when soil inocula were collected closer to focal adult trees. An inoculation experiment with rhizobial isolates promoted nodulation of seedlings grown in soil taken at close distances to adult trees, suggesting that rhizobial densities are suboptimal at these locations. 3. Fusarium oxysporum, a pathogen of O. glaberrima seedlings, produced exudates that inhibited growth of most bacteria isolated from nodules. Accordingly, F. oxysporum negatively affected rhizosphere colonization of rhizobia in a co-inoculation experiment. Contrariwise, certain Burkholderia isolates (from nodules and the rhizosphere) were identified that possess the ability to inhibit growth of F. oxysporum. The majority of the antagonistic bacteria were isolated from locations with fungal pathogens, suggesting competition between fungi and rhizosphere bacteria. 4. Exclusion of pathogenic fungi by application of fungicides promoted nodulation of O. glaberrima seedlings under growth-room and field conditions. 5. Synthesis. Our findings indicate that soil-borne pathogens surrounding adult trees are microbial keystone species that locally influence interactions between seedlings and plant-associated bacteria.

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Section: Discussionmentioning

confidence: 99%

Distance‐dependent effects of pathogenic fungi on seedlings of a legume tree: impaired nodule formation and identification of antagonistic rhizosphere bacteria

Liu

Xie

et al. 2016

Journal of Ecology

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“…Occidiofungin is a structurally unique antifungal peptide sharing homology to cepacidine A (21, 23) and the recently discovered burkholdines (28). Occidiofungin is the first antifungal from this group to demonstrate its physical stability and in vitro activity against a human fungal pathogen.…”

Section: Discussionmentioning

confidence: 99%

Occidiofungin's Chemical Stability and In Vitro Potency against Candida Species

Ellis

Gosai

Emrick

et al. 2012

Antimicrob Agents Chemother

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Occidiofungin is a cyclic glyco-lipopeptide produced by Burkholderia contaminans. MICs against Candida species were between 0.5 and 2.0 g/ml. Occidiofungin retains its in vitro potency in the presence of 5% and 50% human serum with a minimal lethal concentration (MLC) of 2 and 4 g/ml, respectively. Time-kill and postantifungal effect (PAFE) experiments of occidiofungin against Candida albicans were performed. The results demonstrate that occidiofungin is fungicidal. Occidiofungin was also found to be a very stable molecule. It is resistant to extreme temperatures and pH and maintains its activity following exposure to gastric proteases.

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“…Although a single purified burkholdine was not employed, to date all members of the burkholdine family produced by strain 2.2N have equal specific activity. 3,4 In the sonicated suspension used here, anti-yeast and anti-fungal activity would have been due to all related burkholdines; no synergistic activity has been demonstrated between individual burkholdines. 3,4 Killing of yeast cells as measured by decrease of colony-forming units coincided with the release of intracellular maltase and loss of viability ( Table 1).…”

Section: Discussionmentioning

confidence: 94%

“…3,4 In the sonicated suspension used here, anti-yeast and anti-fungal activity would have been due to all related burkholdines; no synergistic activity has been demonstrated between individual burkholdines. 3,4 Killing of yeast cells as measured by decrease of colony-forming units coincided with the release of intracellular maltase and loss of viability ( Table 1). The short time needed to exhibit killing, lysis, and loss of viability suggests that they reflect the primary result of burkholdine activity, not a secondary consequence of some other effect (e.g., ATP reduction).…”

Section: Discussionmentioning

confidence: 94%