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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 is informally called Fungi Imperfecti because of their ability to reproduce asexually. But we now know that many can also 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.

Figure 1: Soil Fungi (video and audio)

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