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Food microbiology- mold reproduction-spores

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Saajida Sultaana

Molds reproduce both sexually and asexually. Asexual reproduction occurs through spores, including conidiospores, arthrospores, and sporangiospores. Sexual reproduction results in oospores in aseptate molds, zygospores in zygomycetes, ascospores in ascomycetes formed in sacs called asci, and basidiospores in basidiomycetes formed on club-shaped basidia. Spores spread by air and germinate under favorable conditions to form new mold growth.

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MICROBIOLOGY QUICK LEARN FOOD MICROBIOLOGY MOLDS Saajida Sultaana Mahusook
• Molds are multicellular, filamentous fungi whose growth on foods can be readily recognized by its fuzzy or cottony appearance. Reproduction of molds • Reproduction of molds is mainly by asexual spores which are small, light, and resistant to drying. • Spores are produced in large numbers and are readily spread by air. • Sexual spores are also produced and such molds are called perfect and classified under • either Oomycete or Zygomycete if aseptate; • or Ascomycete or Basidiomycete if septate. Fungi Imperfectii (septate) have only asexual spores. Spores that settle on favorable substrates can initiate a new phase of growth and develop into a new mold under favorable conditions.
Types of asexual spores • Conidiospore ― Conidiospore or conidia are single celled, bicelled or multicelled structure born on the tip or side of aerial hyphae called conidiophore. Conidia are born singly or in chains. Examples: Penicillium, Apergillus • Arthrospore or oidia ― Arthrospores are formed by the breaking up of fungal mycelium. A spore is formed by separation followed by fragmentation of hyphae. Examples: Trichosporium, Geotrichum
• Sporangiospore ― These asexual spores are produced in a sac like structure called sporangia (singular Sporangium). Sporangium contains large numbers of haploid spores, which are released by rapture of sporangial wall and are produced at the end of special aerial hyphae called sporangiophore. Example: Rhizopus • Chlamydospore ― Hyphal cell or portion of hyphae contracts, loose water, round up and develops into thick walled chlamydospore. These are usually formed during unfavorable condition and are thick walled single celled spore, which are highly resistant to adverse condition. When favorable condition returns, each chlamydospore gives rise to a new individual mold. Examples: Ascomycetes, Basidiomycetes, Zygomycetes, Histoplasma capsulatum.
Types of sexual spores • Oospore ―These are formed in aseptate molds (Oomycetes) by the union of a small male gamete with a large female gamete within a special female structure called Oogonium. There are one or more oospores in each oogonium. Example: Downy mildews which cause late blight of potatoes. • Zygospore ― Zygospores are thick walled spores formed when two sexually compatible hyphae or gametangia of certain fungi (Zygomycetes) fuse together. In suitable condition, zygospore germinates to produce a single vertical hyphae which forms a sporangium and releases its spores. • Both oospores and zygospores are covered by tough wall and resistant to drying. • Ascospore ― It is formed by the fusion of two cells from the same mycelium or from two separate mycelia (Ascomycetes). The spores are usually single celled produced in a sac called ascus (plural; asci) containing 4-8 ascospore but the number may vary from species to species. • Basidiospore ― It is a reproductive spore produced by Basidiomycetes, which include most mushrooms, smuts, etc., Thses single celled spores are born in a club shaped structure called basidium.
Reference • Food Microbiology by Martin R. Adams and Maurice O. Moss, 3rd e. • Food Microbiology by William C. Frazier and Dannis C. Westhoff, 5th e.

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Food microbiology- mold reproduction-spores

  • 1. MICROBIOLOGY QUICK LEARN FOOD MICROBIOLOGY MOLDS Saajida Sultaana Mahusook
  • 2. • Molds are multicellular, filamentous fungi whose growth on foods can be readily recognized by its fuzzy or cottony appearance. Reproduction of molds • Reproduction of molds is mainly by asexual spores which are small, light, and resistant to drying. • Spores are produced in large numbers and are readily spread by air. • Sexual spores are also produced and such molds are called perfect and classified under • either Oomycete or Zygomycete if aseptate; • or Ascomycete or Basidiomycete if septate. Fungi Imperfectii (septate) have only asexual spores. Spores that settle on favorable substrates can initiate a new phase of growth and develop into a new mold under favorable conditions.
  • 3. Types of asexual spores • Conidiospore ― Conidiospore or conidia are single celled, bicelled or multicelled structure born on the tip or side of aerial hyphae called conidiophore. Conidia are born singly or in chains. Examples: Penicillium, Apergillus • Arthrospore or oidia ― Arthrospores are formed by the breaking up of fungal mycelium. A spore is formed by separation followed by fragmentation of hyphae. Examples: Trichosporium, Geotrichum
  • 4. • Sporangiospore ― These asexual spores are produced in a sac like structure called sporangia (singular Sporangium). Sporangium contains large numbers of haploid spores, which are released by rapture of sporangial wall and are produced at the end of special aerial hyphae called sporangiophore. Example: Rhizopus • Chlamydospore ― Hyphal cell or portion of hyphae contracts, loose water, round up and develops into thick walled chlamydospore. These are usually formed during unfavorable condition and are thick walled single celled spore, which are highly resistant to adverse condition. When favorable condition returns, each chlamydospore gives rise to a new individual mold. Examples: Ascomycetes, Basidiomycetes, Zygomycetes, Histoplasma capsulatum.
  • 5. Types of sexual spores • Oospore ―These are formed in aseptate molds (Oomycetes) by the union of a small male gamete with a large female gamete within a special female structure called Oogonium. There are one or more oospores in each oogonium. Example: Downy mildews which cause late blight of potatoes. • Zygospore ― Zygospores are thick walled spores formed when two sexually compatible hyphae or gametangia of certain fungi (Zygomycetes) fuse together. In suitable condition, zygospore germinates to produce a single vertical hyphae which forms a sporangium and releases its spores. • Both oospores and zygospores are covered by tough wall and resistant to drying. • Ascospore ― It is formed by the fusion of two cells from the same mycelium or from two separate mycelia (Ascomycetes). The spores are usually single celled produced in a sac called ascus (plural; asci) containing 4-8 ascospore but the number may vary from species to species. • Basidiospore ― It is a reproductive spore produced by Basidiomycetes, which include most mushrooms, smuts, etc., Thses single celled spores are born in a club shaped structure called basidium.
  • 6. Reference • Food Microbiology by Martin R. Adams and Maurice O. Moss, 3rd e. • Food Microbiology by William C. Frazier and Dannis C. Westhoff, 5th e.