Lecture 9 9/19 - Yeast and Molds

Side notes:
• Exam 1 Monday 24th in LHA
• No class next week Wednesday (26th) and Thursday (27th)
• Paper coming up.

Dr. Knipp's Maserati ------->


Audio for today's lecture available here.

• Quick Review
  
• • Bacillus subtilis – has endospores
• • Staphylococcus epidermidis – grape like structure
• • Clostridium botulinum – exotoxins
• • Escherichia coli – gram (-)
• • Corynebacterium diphtheriae – exotoxin
• • Mycoplasma pnemonea – no cell wall
• • All fungi are eukaryotic – well defined nucleus

• YEASTS - simple, unicellular, grows well in sab-dex(so do molds) because it has a lot of sugar and a low pH.
• Ex. Schizosaccharomyces octosporus – budding and fission reproduction (asexual). Has 8 spores in the ascospores
• Cryptococcus neoformans – yeast pathogen
• Some yeasts can be 2-20 micrometers
• Can be found around the soil around orchards/vinyards, where the fruit hits the ground (sugary)
• Very thick cell walls. All molds and yeasts are gram (+)
• Some undergo budding and fission which is asexual reproduction. Others form ascospores which are bag like structures.
• Candida albicans – has conidia spores
• Yeasts can only bud (asexual) and are found in deutero’s
• • Characteristics of yeasts:
• prefer 30º C
• they like sugars
• Some are pathogens ex. candida and Cryptococcus
• Sacchromyces cerivesea – baking
• Saccharomyces carlsbergensis – beer making. If you can take their yeast you can recreate their beer
• Sacchromyces lipsoides (not on yellow sheet) – wine making. If you can take their yeast you can recreate their wine.
• Yeast are a good source of B vitamens
• Possible food source – single celled proteins.
• Chocolate cherries (margies candy)
• • Dip cherry in a sugar enzyme solution and then dip it in chocalate. The gooiness comes from the sugar/enzyme/yeast mixture breaking down the sugar.
• MOLDS
• Composed of hyphae – long strands
• • Can either have cross walls or no cross walls
• • Aseptate and septate hyphi
• • If you wind the long strands you get mycelium
• • Well defined mycelli would be found in something like penicillium.
• Similar to yeasts except for the filaments
• They produce sexually and asexually (see handout)
• Asexual is most common form of reproduction
• Conidia – way that most molds actually divide
• Some molds bud and form ascospores which puts them in the category ascomycetes. Also found in basidiomycets, dueteromycetes and zygomycetes.
• If a mold can reproduce it will try to do it asexually. If it can do sexual reproduction than it is in either ascomycetes basidiomycetes or zygomycetes.
• If it forms a bag like structure it is in the ascomycetes.
• If it forms a club structure it is a basidiomycote (mushrooms)
• Zygomycetes – asexually form a big black ball.
• Ex. Rhizopus – hyphea that don’t have cross walls, aseptate.
• They are a sporangium with sporangium spores in it. They blow/spread easily
• When two hyphea’s come together they form a Zygospore which is a sexual spore
• have there own sexual spore and there own asexual spore
• Characteristics/uses of Molds
• Grow well in sugars and low pH values
• Aerobes – you need air for them to grow.
• Used to produce a lot of different industrial acids. Example: citric acid (soda, Orange juice)
• Mold Enzymes – make cloudy cider clear.
• Enzymes – mold enzymes take cider to juice
• Cheeses – molds are necessary to ripen cheeses
• Blue cheese
• Penicillium roqueforti – gives it the bluish color
• Antibiotics
• Soy sauce
• Yeasts are facilitatively anaerobic – if air is they will respire. If it is not there they will ferment.
• Clostridium – ferments, it is anaerobic.
• • Pathogens
• Candida albicans – localized
• Easily treatable → Monostat
• Cryptococcal meningitis – usually breath in air contaminated with bird feces. (systemic)
• Hard to treat
• Amphotercin B – many side effects but one of the few things that works against systemic infections.
• Molds that cause Ringworms (localized infections)
• Microsporum canis - found in dogs and cats.
• Microsporum audouini - ringworm of the scalp
  
• Epidermophyton flocossum - jock itch
  
• Trichophyton rubrum -
  
• Sporothrix schenkii – subcutaneous infection
• Molds that cause (systemic infections)
• Coccidioides immitis
• Histoplasma capsulatum
• Aspergillus fumingatus
• Pneumocystis jiroveci
• o Ringworms – Cutaneous Mycoses (“tinea” means “worm”). Easily treatable with some tough actin’ tinactin!
• • Microsporum canis – found in dogs and cats. Causes problems on the arm.
• • Tinea Capitis (microsporum, trichophyton)– in the scalp
• • Tinea Barbae (trichophyton) – ringworm in the beard
• • Tinea Corporis (microsporum, trichophyton) – of the body
• • Tinea Cruris (epidermophyton) – of the crotch, from jock straps
• • Tinea Pedis (trichophyton) – of the foot. From shower stalls
• • Tinea manuum (microsporum, trichophyton) – of the hand
• • Tinea unguium (trichophyton, epidermophyton) – of the nail