Study Questions: Student Presentations:

 

Kojic Acid - Pummi Singh 11/19/13

 

How do the Aspergillus flavus and Aspergillus oryzae strains that produce kojic acid differ?  Why is A. oryzae considered safe for industry?

 

Aspergillus oryzae is an important industrial fungus.   What are some of the natural products it produces, and what are products that genetically-modified strains produce?

 

How is kojic acid used in the cosmetics industry? How specifically is it thought to work?

 

How else is kojic acid used in industry?

 

Although kojic acid has been implicated as a mutagen, why is this not a general concern for its current uses?

 

Claviceps purpurea – its Impact on History –Patricia Espinosa 12/3/13

 

Claviceps purpurea is a plant parasite on cereal grains.  

 

How does it impact rye production?  How does it enter plants and how does it affect the quality of rye harvests?

 

What is its major impact on humans?

 

What different efforts are made to control or limit the disease?

 

Does C. purpurea produce one major secondary metabolite that causes disease?  Explain.

 

Although ingestion of C. purpurea contaminated products, like bread made from infected rye seed flour, can have serious and deadly consequences, how is it possible that ergot products are used medicinally?

 

What important product from Claviceps was responsible for a significant movement in the 1960Õs?  Was this product responsible for the toxicity of ergot-contaminated rye products?

 

Rhizopus microsporus –Burkholderia rhizoxinica Symbiotic Association and Rhizoxin Production – Nomatter Chingandu 12/3/13

 

R. microsporus is an important plant pathogen in Asia.  How does it cause disease?
What phylum is it from?

 

What two critical factors does the endosymbiont Burkholderia rhizoxinica provide to R. microsporus that allows it to be a rice pathogen? 

What is the mechanism of action of rhizoxin? How does rhizoxin affect cell growth?

 

Unlike many bacterial endosymbionts, Burkholderia rhizoxinica does not require its host for growth/survival. What does the bacterium get from the interaction with R. microsporus?

 

Ectomycorrhizae - Noah Mark 12/3/13-12/5/13

 

What is the rhizosphere?

 

How are mycorrhizae different from other plant fungus associations, for example that of Claviceps purpurea or Rhizopus microsporus?

 

Are ectomycorrhizal fungi associated with most plant roots? Are they associated with a particular type of plant?

 

Are there more species of ectomycorrhizal fungi or endomycorrhizal fungi (you may need to go back to an old lecture to figure this out!)?

 

How do ectomycorrhizal fungi differ from endomycorrhizal fungi in terms of the phylum they are from and whether they can be grown in the lab?

 

How do mycorrhizal fungi benefit from their interactions with their host and how do the hosts benefit?

 

How do Ectomycorrhizal fungi differ from most other fungi in the Basidiomycota in terms of their ability to digest particular substrates?

 

 

Fusarium Diseases – Nancy Schoenhofer 12/5/13

 

How are Fusarium graminearum- infected plants recognized? (what are the symptoms?)

What are the signs of F. graminearum infection?

 

What disease is caused by F. oxysporum f. sp. cubense? What does Òf. sp.Ó mean?

How does this disease affect the infected plants?   Why does it affect the plants in this way?

 

 

Industrial use of fungi in citric acid production – Ana Avelar 12/5/13

 

From what was citric acid first isolated?  When did this occur? 

Most citric acid is isolated from Aspergillus niger. Was this the fungus from which it was originally isolated and commercially produced?

 

For what purposes is citric acid used commercially? 

 

Is citric acid a chemical found in most organisms or is it uniquely found in fungi? Explain.

 

How is citric acid produced?

 

Is citric acid the only useful industrial product produced when A. niger is grown for production?  Explain.

 

Insect-Fungal Associations – Chantelle Khambholja 12/5-12/10/13

 

What are the differences between commensal, mutualistic and parasitic relationships between insects and fungi? 

 

What is a mycophagous relationship between a fungus and an insect?  Is this a common or somewhat rare relationship?

 

Cordyceps are said to be insect parasites.  Why?  How do they interact with their insect hosts?

 

Are these fungi thought to be regionally localized or widespread?

 

How do ants respond to infection of their colony by Ophiocordyceps unilateralis?

 

Why has there been a great demand for Ophiocordyceps sinensis infected caterpillar mummies?

 

Beauvaria bassiana is used commercially as an insect biocontrol agent. Is it a narrow host agent, or a broad host agent?
How, where and when was it originally identified?

 

White Nose Syndrome – Melanie Burros 12/10/13

The fungus that causes white nose syndrome is said to be psychrophilic.  What does this mean, and why does that make it particularly damaging to infected bats?

 

Is white nose syndrome an old disease in the US?  Explain. 

 

Is WNS considered a minor or major disease of bats? Explain.

 

Is Geomyces destructans (Pseudogymnoascus destructans) a respiratory pathogen? Explain.

 

How do bats get infected by P. destructans? Is this the same mode of infection, or different for Coccidioides (from Medical Mycology lecture)?

 

Clinical Mycology – Candi Grado – 12/10/13

 When a clinician tries to determine what might have caused a disease in a patient, why is it important to know:

            a.  the travel history of the patient?
            b.  the immune status of the patient?

 

 

What does the clinician look at to try to determine what organism might have caused the infection?

 

In examining human specimens, like sputum, what is the purpose of KOH in preparing the sample?

 

What are the advantages and disadvantages to molecular diagnosis of fungi isolated from patients with a disease?

 

 

Fungiculture Ant Gardeners – John McMullen


What is the purpose of harvesting leaves by leaf cutter ants?  How do the ants use the leaves?

 

In ant-fungus interactions where the ants farm the fungus, are all interactions the same? Explain.

 

How do the fungi in the leaf cutter ant- fungus interactions differ in growth and spore dispersal from other related fungi?

 

What are the benefits to the ants from farming fungi?  Are there benefits to the fungus?

 

How are the fungi that are involved in the leaf cutter ant-fungus interaction different and unique from related fungi, in terms of their nutritional abilities?