Actinomycetes are a group of bacteria that look like fungi. While both actinomycetes and fungal hyphae are filamentous, the big difference between them is that actinomycetes are prokaryotic organisms, meaning they lack a nucleus, while fungal hyphae are eukaryotic organisms, meaning they have a nucleus. Another difference is that actinomycetes are typically aerobic, while fungal hyphae can be either aerobic or anaerobic. Actinomycetes are also more widespread than fungal hyphae, and are found in a variety of environments, including soil, water, and even within animal hosts. Actinomycetes are also unique in that their cell walls are composed of peptidoglycan, which gives them their distinctive filamentous shape, while fungal hyphae have cell walls composed of chitin. Finally, actinomycetes produce spores, while fungal hyphae produce conidia.