Growth And Reproduction

Most fungi can grow in a wide range of temperatures. The ones that do well at 37 degrees are the ones that cause disease in humans. Most fungi are aerobic, there are some facultative anaerobes, but there are no true anaerobes. Fungi thrive at low pHs, so if there is a change in PH, the bacteria die off  fungal overgrowth. So basically fungi are well adapted to survive in lots of places.

Unicellular fungi grow by budding, while multicellular fungi grow by branching. In the tip of the mold the vesicle releases its contents into the space between the cell wall and the membrane and the mold elongates.

Fungal Reproduction

1. Asexual  spores differ in structure and the spores are used to differentiate species. Yeasts bud and so have no genetic recombination. Chlamydospores are similar to bacterial spores as in they are resistant and are able to survive unfavorable conditions.

2. Sexual  2 haploids combine to form a diploid. We also use these spores to differentiate species.

   1. Plasmogamy  2 haploid nuclei fuse into one cell.

   2. Karyogamy  the nuclei fuse so now it’s a diploid structure.

   3. Meiosis  has 2 haploid nuclei again.

   4. Progeny  have sexual spores again.

Fungi imperfecta are fungi without the ability to reproduce sexually. Most human pathogens are in this category. As you’ll read you’ll see that some fungi have two different names. This is because sexual reproduction was not originally seen in many human pathogens. They did some manipulating in the lab and saw sexual reproduction and so gave the fungi new names based on how they reproduced. But the old names were still in common use, so now we use both.

Category: Microbiology Notes