Unique Feeding Method

Fungi lack chlorophyll, the green pigment that enables plants to make their own food. Consequently, fungi cannot synthesize their own food the way plants do. In order to feed, fungi release digestive enzymes that break down food outside their bodies. The fungus then absorbs the dissolved food through its cell walls.

Depending as they do on outside sources for food, fungi have developed various living arrangements that enhance their opportunities for food absorption. Some fungi live as parasites, feeding on living plants, animals, and even other fungi. Certain fungus parasites injure plants and animals, causing millions of dollars of damage to farm animals, crops, and trees each year. For example, the fungus Ophiostoma ulmi, which causes Dutch elm disease, has killed more than half of the elm trees in North America since it was accidentally introduced there in the 1930s.

Fungi that obtain their food by breaking down dead organisms or substances that contain organic compounds, such as starch and cellulose, are called saprobes or saprophytes. While they are invaluable decomposers of organic material, saprobes can also cause food spoilage and destroy wood products. During the American Revolution (1775-1783), more British ships were destroyed by wood-digesting saprobes than by enemy attack. Some saprobes even grow in aviation fuels, where they breakdown the fuels, destroying their usefulness.

Some fungi also form highly specialized relationships with other organisms (see Symbiosis). For example, the roots of most plants develop a mutually beneficial association with fungi to form mycorrhizae. Mycorrhizae greatly increase the nutrient-absorbing capacity of the plant root—the fungus absorbs minerals from the soil and exchanges them for organic nutrients synthesized by the plant. Fungi also form mutualistic associations with various animals. For example, leaf-cutting ants cut pieces of leaves and bring them into their underground nests, where they feed them to certain fungi. These fungi primarily live in ant nests, and the ants eat nothing but the fungi. Some termites and wood-boring beetles use fungi to break down the cellulose in wood, making the wood easier for the insects to digest. Plant parasites such as rusts invade plant cells via specialized structures called haustoria that absorb nutrients from the cell.

more info at: oralthrushandcandidaalbicans.htm