Zygomycota Mucromycotina Mucorales part 1 Terrestrial fungi
1. Fungi form a monophyletic group. Fungi -2011 No motile cells Mucorales *
http://www.mykoweb.com/articles/index.html#apm1_4 Cryptomycota
Mucorales
Mucorales Vegetative hyphae typically lack septa Under certain conditions mucors may grow as a yeast cells (e.g., anaerobic, liquid culture) Septa are associated with reproductive structures as are rhizoids Cell wall chitin and chitosan Hyphae or yeast cells contain one to many haploid nuclei Asexual reproduction by sporangia with non-motile, sporangiospores Sporangiospores germinate to form hyphae Sexual reproduction - gametangial fusion, zygospores (formed in zygosporangium), germ sporangium Chlamydospores may be formed saprobic, parasitic on plants, animals and other fungi Considerable industrial use, organic acids, etc.
Food Products - Tofu or sufu (Chinese cheese) A soft cheese-type product made from cubes of soybean curd using fermentation by Actinomucor elegans Tempeh A solid cake-like product from soybeans fermented with Rhizopus oligosporus
Cunninghamella - Members of this genus are often used in studies investigating the metabolism of drugs, because these species metabolize a wide range of drugs in manners similar to mammalian enzyme systems. Many species are also capable of oxidizing polycyclic aromatic hydrocarbons, a class of stable organic molecules that tends to persist in the environment and contains many known carcinogenic and mutagenic compounds. Mucormycosis is caused by common fungi frequently found in the soil and in decaying vegetation. Most individuals are exposed to these fungi on a daily basis -- but people with immune disorders may be more susceptible to infection. As such, it usually infects those who are immunocompromised.
In agriculture used for seed treatment and plant growth enhancer, and as a ecologically friendly biopesticide substance that boosts the innate ability of plants to defend themselves against fungal infections. Also, filtration processes, scratch free surfaces, clots blood, fat burner, etc. Chitosan is produced commercially from chitin, which is the structural element in the exoskeleton of crustaceans (crabs, shrimp, etc.) and cell walls of fungi.
Murcorales Moldy strawberries covered with Rhizopus mycelium. Vegetative hyphae often lack septa!
Hyphae of Mucorales with Spitzenkörper
Hyphal apical extension Extension of hyphal apex The mechanisms underlying the growth of fungal hyphae are based on cell pressure. Internal hydrostatic pressure (turgor) is one of the major forces driving the localized expansion at the hyphal tip which causes the characteristic filamentous shape of the hypha. Turgor and pressure have additional roles in hyphal growth, such as causing the mass flow of cytoplasm from the basal mycelial network towards the expanding hyphal tips at the colony edge.
Asexual reproduction Hyphae with haploid nuclei Sexual rerproduction
Asexual Reproduction Reproduce asexually by producing sporangiospores within a sporangium. sporangiophore hypha Macrosporangia rhizoids Sporangiospores inside sporangial wall columella microsporangia
Macrosporangia yellow pigment is β-carotene
Macrosporangia response to light and gravity gravity 10-12 hrs. light The Macrosporangia of Phycomyces blakesleeanus has been investigated for the variety and sensitivity of its responses to light, particularly the phototropism (response to blue light). Other light responses investigated in detail are the regulation of sporangiophore development and the regulation of the biosynthesis of the pigment beta-carotene. In addition, the Phycomyces sporangiophore reacts to a variety of environmental stimuli, including gravity, touch, wind, and the presence of nearby objects by changing the speed and direction of growth.
Asexual reproduction Hyphae, multiple haploid nuclei Sexual reproduction
Sexual Reproduction Sexual spores are called zygospore(s) contained within a zygosporangium A. F. Blakeslee in 1904 discovered that many of these fungi are heterothallic, that is, they require two compatible partners to produce sexual spores. Sex hormones are known to facilitate sexual reproduction among some zygomycetes. For example, hyphae of Mucor species for the + and - mating strains are known to produce trisporic acids which are volatile (+ strain yields trisporates; - strain yields trisporins) and diffuse through the air. Volatiles stimulate progametagia production and the synthesis of carotene (a precursor for trisporic acids) and trisporic acids. A positive feedback mechanism is formed between the two compatible strains leading to physical contact of progametagia and sexual reproduction. Heterothallism (Gr. heteros = different from, thallos = shoot; the condition of being self-sterile, requiring a partner for sexual reproduction) and homothallism (Gr. homos = alike, thallos = shoot; the condition of being self fertile; able to reproduce sexually without a partner) exhibited among species of Mucorales.
When compatible mycelia of Phycomyces blakesleeanus meet, individual hyphae establish intimate contact, developing finger-like outgrowths and seeming to grapple with one another. This lets them exchange chemical signals which establish that they are indeed sexually compatible. Then the two hyphae grow apart again, only to loop back, swelling as they approach each other, and finally meeting head-on. They have become gametangia, which fuse when their tips touch. Note that there isn't any sexual differentiation in size or shape here: since we can't call them male and female, we simply label the mycelia '+' and '-'
Mating system heterothallic or homothallic - + Phycomyces blakesleeanus Cunninghamella homothallica
Sexual Compatibility Regulated by trisporic acid, a sex pheromone Enhances secretion of specific precursors of trisporic acid and betacarotene Positively regulates its own synthesis by stimulating rate of precursor formation in paired cultures Induces zygophore formation Represses sporangiophore formation triporate trisporin
asexual sexual macrosporangia