How Mold Grows and What Mold Needs to Live
Fungus Behavior in a Mold-Infested World – Fungus Hyphae and Spores
Apr 5, 2009
They come in an assortment of colors and sizes. They spread and grow quietly and with stealth. They can be sniffed out – they are odoriferous and permeate the air with molecules that reveal mold presence, even when unseen. An old house reminds one of the odors of the past, when air conditioners and dehumidifiers were unknown. Back then only a ceiling fan cooled and pushed the house air from place to place .
Moldy Answers to What Is Mold, Why Is Mold, and Where Is Mold
A mold is a filamentous fungus. A filamentous fungus, or mold, is a simple living organism that has a true nucleus, cytoplasm and absorbs (assimilates actually) water-dissolved nutrients: sugars, amino acids, salts. The mold grows by extension of filaments called hyphae. The hyphae form a large mass (mycelium) that looks like a tiny rug or carpet . That mycelial mass or carpet of hyphae produces spores as it turns from white or light gray to a peppery black, or orange, or red, or blue-green, or any of dozens of shades and variations. Thousands to several million spores are produced within hours.
Fungus Spores Have Two Main Functions
The spores of a fungus are important to its continued survival. Spores are responsible for the:
- spread (dissemination) of the mold. Spores are light, have tough walls and can be lofted by wind curents or breezes and carried great distances. Human, animal and inanimate contact causes molds to stick and be carried to other places, or to stay attached and grow in place. Moldy shoes and clothes are quite common evidence of spore germination and fungus growth; and
- survival of the fungus during dry conditions. The single nucleus contains all the information needed to make a whole new fungus. Note: Bacterial endospores are produced internally and are far more resistant to harsh conditions such as heat, dessication and chemicals.
Important Characteristics of Molds
Molds:
- grow in moist places. Molds love rain, high humidity, plumbing, wet rags and just about any wet surface. They grow on wet wood, window sills, plant pots, baths, showers, toilet bowls, sinks, concrete, rain gutters, clothes, and even glass windows and camera lenses. Any moist or wet surface will do. Ask any flood or hurricane victim if they know about mold and one look back from them is more than an answer.
- need oxygen or air, similar to most organisms.
- grow on simple and complex nutrient sources. Sugars, starches, proteins are all used.
- are major decomposers of wood, leaves, dead animals and plants; bacteria do likewise.
- are used to make tempeh, cheeses, soy sauce and antibiotics.
The character of molds is to grow quickly where there is moisture, air and food. Molds can grow just about anywhere considering that they have such very simple needs. If there is sufficient moisture they will grow on paper, cardboard and wall board or masonite. There are lots of basements and crawlspaces that are improperly or unvented and they are ideal for mold growth.
Mold Grows on Paper, Glass and Many Materials
Two questions come to mind. How do you eat paper? How do you grow on glass or tile? Many mold have cellulases, enzymes that break down paper to glucose, the universal sugar for energy and other metabolic functions such as building more fungus. Cellulase is released beyond the walls of the fungus and begins to digest the food (cellulose). Cellulose dissolves to sugar and that sugar can get back into the fungus. The paper is being digested outside the fungus!
Tiles, glass, porcelain may seem a little strange, but fungi can stick to surfaces and assimilate many nutrients that dissolve in water: amino acids, sugars, fatty acids, ammonia, nitrates and minerals. If the fungus is growing, then there is enough to eat in that environment.
Mold Control
Mold can be controlled by drying, dehumidification, mold inhibitors and fungicides.
Sources
Campbell, N.A., L.G. Mitchell, and J.B. Reece. 2000. Biology, Concepts and Connections. Addison Wesley Longman, Inc. , San Francisco. 809pp
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