This video describes soil fungi, which are a diverse group of eukaryotic organisms that have rigid cell walls and lack chlorophyll. Soil fungi often make up more biomass in soil than any other microbial group. These filamentous organisms are heterotrophic, which means they consume organics as a carbon source. Fungi can produce abundant hyphae (or threads) that are able to extract nutrients and water from many locations within the soil matrix. Also, fungi are active in decomposing plant residues and animal tissues. The video shows a close-up of fungal hyphae active in decomposing an insect or macrofauna (relatively larger animal). Most fungi that grow on artificial media originate from asexual spores. This group informally is called Fungi Imperfecti because of their ability to reproduce asexually, but for many we now know they also can reproduce sexually and mycologists (those who study fungi) often classify them as Ascomycota. The asexual spores or conidia are generated by special cells called phialides. Penicillium is viewed at 40x, 100x, 500x, and 1,000x magnification. At 1,000x, the individual phialides and conidia are easy to see. A colony of Aspergillus is also shown at high magnification. Cytoplasmic streaming can be seen at 500x and 1,000x magnification within a fungal filament. This fungus does not have cross walls, or septa. A downloadable, high-resolution version of this video is available at http://www.agron.iastate.edu/~loynachan/mov/.
The insect being decomposed by fungi was isolated on a buried slide in soil and stained with rose bengal. The asexually reproducing fungi were grown at room temperature on medium containing streptomycin and rose bengal. The isolates were taken from an Iowa soil. The cytoplasmic streaming video was captured on cornmeal extract plates sprinkled with soil and was a chance occurrence of both organisms appearing in the same location on the plate. The video was captured with bright-field microscopy and captions added using Adobe Premiere.
Dindal, D. L. 1990. Soil biology guide. John Wiley and Sons, New York, NY.
Sylvia, D. M., J. J. Fuhrmann, P. G. Hartel, and D. A. Zuberer. 2005. Principles and applications of soil microbiology. Pearson Prentice Hall, Upper Saddle River, NJ.