Faculty Opinions recommendation of Social transfer of pathogenic fungus promotes active immunisation in ant colonies.

Social Transfer of Pathogenic Fungus Promotes Active Immunisation in Ant Colonies

PLoS Biology ◽

10.1371/journal.pbio.1001300 ◽

2012 ◽

Vol 10 (4) ◽

pp. e1001300 ◽

Cited By ~ 111

Author(s):

Matthias Konrad ◽

Meghan L. Vyleta ◽

Fabian J. Theis ◽

Miriam Stock ◽

Simon Tragust ◽

...

Keyword(s):

Pathogenic Fungus ◽

Active Immunisation ◽

Ant Colonies ◽

Social Transfer

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Ammonia Production by Streptomyces Symbionts of Acromyrmex Leaf-Cutting Ants Strongly Inhibits the Fungal Pathogen Escovopsis

Microorganisms ◽

10.3390/microorganisms9081622 ◽

2021 ◽

Vol 9 (8) ◽

pp. 1622

Author(s):

Basanta Dhodary ◽

Dieter Spiteller

Keyword(s):

Fungal Pathogen ◽

Closed Loop ◽

Pathogenic Fungus ◽

Ant Colonies ◽

Strong Activity ◽

Streptomyces Sp ◽

Mutualistic Symbiosis ◽

Leaf Cutting ◽

Leucoagaricus Gongylophorus ◽

Production Of Ammonia

Leaf-cutting ants live in mutualistic symbiosis with their garden fungus Leucoagaricus gongylophorus that can be attacked by the specialized pathogenic fungus Escovopsis. Actinomyces symbionts from Acromyrmex leaf-cutting ants contribute to protect L. gongylophorus against pathogens. The symbiont Streptomyces sp. Av25_4 exhibited strong activity against Escovopsis weberi in co-cultivation assays. Experiments physically separating E. weberi and Streptomyces sp. Av25_4 allowing only exchange of volatiles revealed that Streptomyces sp. Av25_4 produces a volatile antifungal. Volatile compounds from Streptomyces sp. Av25_4 were collected by closed loop stripping. Analysis by NMR revealed that Streptomyces sp. Av25_4 overproduces ammonia (up to 8 mM) which completely inhibited the growth of E. weberi due to its strong basic pH. Additionally, other symbionts from different Acromyrmex ants inhibited E. weberi by production of ammonia. The waste of ca. one third of Acomyrmex and Atta leaf-cutting ant colonies was strongly basic due to ammonia (up to ca. 8 mM) suggesting its role in nest hygiene. Not only complex and metabolically costly secondary metabolites, such as polyketides, but simple ammonia released by symbionts of leaf-cutting ants can contribute to control the growth of Escovopsis that is sensitive to ammonia in contrast to the garden fungus L. gongylophorus.

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High-pressure freezing and freeze substitution of teliospores of the rust fungus Gymnosporangium clavipes

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100161011 ◽

1990 ◽

Vol 48 (3) ◽

pp. 692-693

Author(s):

Robert W. Roberson

Keyword(s):

High Pressure ◽

Room Temperature ◽

Pathogenic Fungus ◽

Rust Fungus ◽

Freeze Substitution ◽

Ice Crystals ◽

High Pressure Freezing ◽

Thin Walled Structures ◽

Cytological Changes ◽

Dextran Solution

The use of cryo-techniques for the preparation of biological specimens in electron microscopy has led to superior preservation of ultrastructural detail. Although these techniques have obvious advantages, a critical limitation is that only 10-40 μm thick cells and tissue layers can be frozen without the formation of distorting ice crystals. However, thicker samples (600 μm) may be frozen well by rapid freezing under high-pressure (2,100 bar). To date, most work using cryo-techniques on fungi have been confined to examining small, thin-walled structures. High-pressure freezing and freeze substitution are used here to analysis pre-germination stages of specialized, sexual spores (teliospores) of the plant pathogenic fungus Gymnosporangium clavipes C & P.Dormant teliospores were incubated in drops of water at room temperature (25°C) to break dormancy and stimulate germination. Spores were collected at approximately 30 min intervals after hydration so that early cytological changes associated with spore germination could be monitored. Prior to high-pressure freezing, the samples were incubated for 5-10 min in a 20% dextran solution for added cryoprotection during freezing. Forty to 50 spores were placed in specimen cups and holders and immediately frozen at high pressure using the Balzers HPM 010 apparatus.

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