Hypha
A hypha (plural hyphae) is a long, branching filament found primarily in fungi, but also in fungus-like bacteria such as Actinomyces and Streptomyces.
In fungi, the hyphal filaments form the feeding thallus, called the mycelium. Thallus, from the Greek thallos, means green shoot and is the actively growing vegetative form of a hypha. Hyphae are also found enveloping the gonidia in lichens, making up a large part of their structure. A typical hypha consists of a tubular wall, usually made of chitin, which surrounds, supports, and protects the cells that compose a hypha. For most fungi, a cell within a hyphal filament is separated from other cells by internal cross-walls called septa (singular septum).
Some forms of parasitic fungi have a portion of their hyphae modified to form haustoria that are able to penetrate the tissues of a host organism. Similar, yet mutualistic forms of penetrating hyphae called mycorrhizae are important in assisting nutrient and water absorption by plants.
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Types of hyphae
- aspetate
- septate: Hyphae with septa, cross-walls that divide fungal hyphae into cells. These septa have pores large anough for ribosomes, mitochondria, and even nuclei to flow from cell to cell.
- pseudohyphae
- basidiomycetous
Growth
Unlike most animal, plant and yeast cells, hyphae do not grow by ordinary cell division. Instead, hyphae extend by tip growth. As the tip extends, walls called septa form to partition each hypha into individual cells, each with its own nucleus copied from the first nucleus. Hyphae also undergo branching, which in different species may occur through bifurcation of a growing tip, or by the emergence of a new tip from the body of a hypha.
References
- Madigan, Michael; Martinko, John (editors) (2005). Brock Biology of Microorganisms, 11th ed., Prentice Hall. ISBN 0-13-144329-1.
See also
External links
Categories
Fungal morphology and anatomy