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Flashcards in Fungi Deck (33)
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1

Fungi

• Ubiquitous in the environment

• ___ms

• ___

• ___

• Used frequently in food and pharmacy applications

• Some are are considered ____ - but ____

• Very ___ species in human flora

• Candida albicans (___) • Oral • Gut • Vaginal • ___ unless something happens with the host

Fungi • Ubiquitous in the environment • Mushrooms • Mold • Yeast • Used frequently in food and pharmacy applications • Some are are considered microbes - but eukaryotic • Very few species in human flora • Candida albicans (yeast) • Oral • Gut • Vaginal • Commensal unless something happens with the host

2

Fungi→ Molds and Yeast

Mold and Yeast are ____

Both are microscopic ____ ___ organisms

• Molds make ___ ___

• Yeast are ___→___ in shape

Fungi→ Molds and Yeast Mold and Yeast are Microbes Both are microscopic single celled organisms • Molds make filamentous hyphae • Yeast are cellular→circular in shape

3

Helpful Fungi

• Food and Pharmacy

• Saccharomyces cerevisiae: (__ ___t) • Helps yeast rise • Yeast fermentation of sugar forms ____• Yeast break down glucose and make CO2

• They also release____ so used to make beer and wine

• Penicillin is byproduct of ____

• ____ needs fungi • Penicillium roquefortii • Penicillium camenbertii

Helpful Fungi • Food and Pharmacy • Saccharomyces cerevisiae: (Bakers yeast) • Helps yeast rise • Yeast fermentation of sugar forms CO2 • Yeast break down glucose and make CO2 • They also release ethanol so used to make beer and wine • Penicillin is byproduct of penicillium • Cheese needs fungi • Penicillium roquefortii • Penicillium camenbertii

4

Environmental Molds & Fungi

Eating dead organic matter (_____) in moist dark areas.

Environmental Molds & Fungi Eating dead organic matter (saprophytes) in moist dark areas.

5

Candida albicans – “a fungus among us”

• A resident of all ___ ___ and __ ___

• Candidiasis • “Thrush” • Mold and fungus is everyehere

• They are ____ so only eat __ ___

• Like ___, ____ areas

• Very rare to get fungal infection from ____  • If you do, you generally have a ___ ___

• Candida albicans is a ___

• Tiny granules are bacteria, longer forms are candida.

• Candida is ____

Can be in ___ form or ___ form and can switch back and forth

Candida albicans – “a fungus among us” • A resident of all mucosal surfaces and dental plaque • Candidiasis • “Thrush” • Mold and fungus is everyehere • They are sachrophytes so only eat dead material • Like moisture, dark areas • Very rare to get fungal infection from environment. • If you do, you generally have a health issue • Candida albicans is a yeast • Tiny granules are bacteria, longer forms are candida. • Candida is dymorphic. Can be in yeast form or hyphae form and can switch back and forth

6

What does “Candida albicans” mean?

• Candidas→___ • Candidate for office wears white toga

• Candid→ __ and ___

• When you grow them in lab, you have large ___e colony formed

• Albicans is from alba which also means ___

What does “Candida albicans” mean? • Candidas→White • Candidate for office wears white toga • Candid→ pure and honest • When you grow them in lab, you have large white colony formed • Albicans is from alba which also means white!

7

Fungi are eukaryotes

• Nucleus

• __ __ ___

• Transcription-translation is ____

• Membrane-bound organelles

• E____ ____ ____

• Molecular biology

• ____ _____

Idealized yeast cell

Candida is ___

All of rules that apply to our cells, apply here

DNA poly and ribosomes are similar to ours

Can’t use Ab to treat candida albican infection.

Fungi are eukaryotes • Nucleus • Membrane-bound DNA • Transcription-translation is separate • Membrane-bound organelles • Endoplasmic reticulum • Golgi • Mitochondria • Molecular biology • DNA polymerases • Ribosomes Idealized yeast cell Candida is eukaryote! All of rules that apply to our cells, apply here DNA poly and ribosomes are similar to ours Can’t use Ab to treat candida albican infection.

8

Yeasts have a cell wall

Yeast have a cell wall

• bacteria have a cell wall

• plants have a cell wall

• mammalian cells __ ___

 

Some yeast have a ____

• Candida__ __

• Cryptococcus neoformans

 

Not made of __ ___or made by___ ___s as bacteria

Candida does not have a capsule,___ or ___

Only unique for its __ ___l and composition of its ____

Candida cell wall

More like insects because has___ and ___ in it

Yeasts have a cell wall Yeast have a cell wall • bacteria have a cell wall • plants have a cell wall • mammalian cells do not Some yeast have a capsule • Candida does not • Cryptococcus neoformans Not made of same components or made by same enzymes as bacteria Candida does not have a capsule, cilia or flagella Only unique for its cell wall and composition of its membrane Candida cell wall More like insects because has chitin and glucans in it

9

Fungal Cell Wall and Membrane

___d cell wall • ___ • ____ • ___

Cell membrane • _____* instead of cholesterol 

Wall and Membrane common targets for anti-fungal drugs

• Most target the ___ though

Fungal Cell Wall and Membrane  Rigid cell wall • glucans • mannoproteins • chitin  Cell membrane • ergosterol* instead of cholesterol  Wall and Membrane common targets for anti-fungal drugs • Most target the membrane though

10

Common Anti-fungals 

Amphotericin B • Binds to _____ in fungal membranes • Disrupts membrane____ • Given by___ for systemic infections ▪____ tolerated (Ampho-terrible) • Given as____ for topical treatment • Use topically or via IV For really bad infections, do IV in hospital • AKA aphoterrible bc it can cross react with our proteins→ make you feel awful • Lozenge: drop that they can put in there mouth that they can suck on for oral infections 

Nystatin* • Binds to ____ in fungal membranes • Applied t____y as ____t or __ ___

* Oral suspension: Liquid that they swish

• Fluconazole and Miconazole* • Inhibits ___ ___ • Applied ____y as an ___ ___/___* or oral ____ • Fluconazole can also be given ____ by ____

Common Anti-fungals  Amphotericin B • Binds to ergosterol in fungal membranes • Disrupts membrane structure • Given by IV for systemic infections ▪ Poorly tolerated (Ampho-terrible) • Given as lozenge for topical treatment • Use topically or via IV For really bad infections, do IV in hospital • AKA aphoterrible bc it can cross react with our proteins→ make you feel awful • Lozenge: drop that they can put in there mouth that they can suck on for oral infections  Nystatin* • Binds to ergosterol in fungal membranes • Applied topically as ointment or oral suspension* Oral suspension: Liquid that they swish • Fluconazole and Miconazole* • Inhibits ergosterol synthesis • Applied topically as an oral gel/cream* or oral suspension • Fluconazole can also be given systemically by tablet

11

Fungal Morphology 

Fungi may exist in two morphologic forms

• ____—____

•____—develop elongated __ ___ called ___

 ▪ Mass of hyphae is a ____

▪ ___

▪ Dimorphic fungi can exist in ____morphology 

Candida albicans is ___ 

Bakers yeast- Saccharomyces 

Candida is interesting bc technically we consider a yeast. o Typical round cell with nucleus o Unicellular o ____ than bacteria 

Sometimes you can have branched fillaments called hyphae.  Candida mainly grows as ____ but can from hyphae  Called dimorphic  When in yeast form, it’s a bett___ ____r an____

Hyphal form→ more ____

Fungal Morphology  Fungi may exist in two morphologic forms • Unicellular—yeasts • Multicellular—develop elongated branched filaments called hyphae ▪ Mass of hyphae is a mycelium ▪ Molds ▪ Dimorphic fungi can exist in either morphology  Candida albicans is dimorphic  Bakers yeast- Saccharomyces  Candida is interesting bc technically we consider a yeast. o Typical round cell with nucleus o Unicellular o Bigger than bacteria  Sometimes you can have branched fillaments called hyphae.  Candida mainly grows as yeast but can from hyphae  Called dimorphic  When in yeast form, it’s a better biofilm former and colonizer  Hyphal form→ more pathogenic.

12

Types of Hyphae

• ___ Hyphae o Formed for ___. o Yeast can have ___al or ____reproduction (use hyphae like pillus in bacteria)

• ____ o Looks more like a ___. • Long branching structures o Seen when ____ and ____host tissue o Hyphae grow down into mucosal surfaces

Types of Hyphae • True Hyphae o Formed for sex. o Yeast can have assexual or sexual reproduction (use hyphae like pillus in bacteria) • Pseudohyphae o Looks more like a fungus. • Long branching structures o Seen when pathogenic and invading host tissue o Hyphae grow down into mucosal surfaces

13

Yeast vs Germ Tube vs Pseudohyphae

All of these are candida

•____ yeast: clonal, asexual reprotduction

• Psudohypahae: Pseudo have ___ __ ___ in between the structures

• Can also make ____ that will spread in environ

• True hyphae: form a __ ___ and are ___ continuous cell that’s not divided up

Yeast vs Germ Tube vs Pseudohyphae All of these are candida • Buddingy yeast: clonal, asexual reprotduction • Psudohypahae: Pseudo have cell wall dividers in between the structures • Can also make spores that will spread in environ • True hyphae: form a germ tube and are one continuous cell that’s not divided up

14

Cell Morphology linked to reproduction, pathogenicity

• “Budding”Yeast o ____ division

• Pseudo-hyphae o __ ___ reproduction o Tissue____

• Germ tubes / True Hyphae o____ reproduction

Cell Morphology linked to reproduction, pathogenicity • “Budding”Yeast o Asexual division • Pseudo-hyphae o Spore-forming reproduction o Tissue invasion • Germ tubes / True Hyphae o Sexual reproduction

15

Candida morphology in vivo Both hyphae make it hard to be_____

Candida morphology in vivo Both hyphae make it hard to be phagocytized

16

Candida in the Flora

• Normal flora

• ___

• ___ ___ • ___ • ____ • Ubiquitous in humans (75%)

• Opportunistic pathogens

• ___ ____ not infectious disease

• ___ ___, local conditions are key

• ___ __ ___ ____ of humans

• Multiple Candida disease states

• ___ of ____form

____ of host tissue by____e form

• Spread in ___ ___

Candida in the Flora • Normal flora • Commensal • Digestive tract • Skin • Vagina • Ubiquitous in humans (75%) • Opportunistic pathogens • Ecological changes not infectious disease • Host health, local conditions are key • most common fungal pathogen of humans • Multiple Candida disease states • Overgrowth of yeast form • Invasion of host tissue by hyphae form • Spread in blood stream

17

• At any given time, ___% of popl has candida in their flora somewhere

o At some time you may not have it and then pick it up for awhile and then it goes away.

• Changes in host make them more susceptible→ opportunistic pathogen

• Most common fungal pathogen of humans because so many of us have it in our flora.

• Can cause disease in a variety of ways o Yeast form overgrowth o Invasion of tissue in hyphal form. Try to grown down and cause local infection o Get into blood stream and cause systemic yeast infectionà SERIOUS. Hospital IV. Means they have some major health issue. Normally body can defend against Candida

• At any given time, 75% of popl has candida in their flora somewhere o At some time you may not have it and then pick it up for awhile and then it goes away. • Changes in host make them more susceptible→ opportunistic pathogen • Most common fungal pathogen of humans because so many of us have it in our flora. • Can cause disease in a variety of ways o Yeast form overgrowth o Invasion of tissue in hyphal form. Try to grown down and cause local infection o Get into blood stream and cause systemic yeast infectionà SERIOUS. Hospital IV. Means they have some major health issue. Normally body can defend against Candida

18

Candida Virulence Factors

• ____ (at least 12 ____l-type proteases) ▪ Proteases can break down___

• ___ (several) • Produces variety of lipases. • Break down __ ____ of host cells and destroy host cells

• ____ factors (20+ cell surface adhesins) ▪ Has to stick to oral surfacesà Makes adhesins ▪ Ability to stick is important. Don’t want to be+ _____ ▪

•____ formation ▪ Good at forming biofilms.

• Morphogenesis ▪ __ ___ vs ___ ___ ▪ Hyphal forms are tissue invasive ▪ Dimorphic change results in diff ___ on the surface. Immune sys may be generated to yeast form but not recognize hyphal ▪ Hyphal hard to phagocytize ▪ Hyphae produce ___ lipase than yeast→ lets it grown down into the tissue

• Can bind ___ but not be ___. This hides ___. Masking effect.

Candida Virulence Factors • Proteases (at least 12 aspartyl-type proteases) ▪ Proteases can break down SIgA. • Lipases (several) • Produces variety of lipases. • Break down cell membranes of host cells and destroy host cells • Adhesion factors (20+ cell surface adhesins) ▪ Has to stick to oral surfacesà Makes adhesins ▪ Ability to stick is important. Don’t want to be swallowed ▪ • Biofilm formation ▪ Good at forming biofilms. • Morphogenesis ▪ Yeast form vs Hyphal form ▪ Hyphal forms are tissue invasive ▪ Dimorphic change results in diff Ag on the surface. Immune sys may be generated to yeast form but not recognize hyphal ▪ Hyphal hard to phagocytize ▪ Hyphae produce more lipase than yeast→ lets it grown down into the tissue • Can bind complement but not be lysed. This hides Ag. Masking effect.

19

Switching morphology changes Pathogenicity Expression 

Adaptability to survive in ____ anatomic sites 

Switching of gene expression dictated by ___ ___.

Presence or absence of ____

Yeast are sensitive to presence or bacteria.

Some bact make them stay in yeast form

• ___  Yeast break down glucose so high sugar diet can lead to___ ___

____  contents:

Quantity and quality  Saliva works against yeast. Wash away. Delivers antimicrobials 

Switch from yeast to hyphae forms 

Hyphae are associated with increase in ___/)____ expression, and result in ___ ___

Switching morphology changes Pathogenicity Expression  Adaptability to survive in diverse anatomic sites  Switching of gene expression dictated by environmental changes • Presence or absence of bacteria  Yeast are sensitive to presence or bacteria. Some bact make them stay in yeast form • Diet  Yeast break down glucose so high sugar diet can lead to yeast overgrowth • Saliva contents: Quantity and quality  Saliva works against yeast. Wash away. Delivers antimicrobials  Switch from yeast to hyphae forms  Hyphae are associated with increase in protease/lipase expression, and result in tissue invasion.

20

C. albicans Biofilms 

C. albicans forms biofilms with ___ ___

 Cooperative behavior

s • __ ___  With oral Strep

• __→ Uses up O2

• __ ___

•___ ___  Produce____ol. High Farnseol will form____ e  Bw yeast and S. Gordonni. Will tell Candida to __ ____ farnesol so Candida will stay as a yeast

___ production  Contributes to biofilm slime.  Allows bacteria to colonize

C. albicans Biofilms  C. albicans forms biofilms with oral bacteria  Cooperative behaviors • Co-aggregation  With oral Strep • Environment modification→ Uses up O2 • Food web • Quorum sensing  Produce Farnesol. High Farnseol will form hyphae  Bw yeast and S. Gordonni. Will tell Candida to stop forming farnesol so Candida will stay as a yeast • EPS production  Contributes to biofilm slime.  Allows bacteria to colonize

21

Some oral Strep suppress pseudo-hyphae formation (____) while others stimulate formation (__ ___). S. Oralis encourages hyphae! Opp of S.gordonii.

Some oral Strep suppress pseudo-hyphae formation (S. gordonii) while others stimulate formation (S. oralis). S. Oralis encourages hyphae! Opp of S.gordonii.

22

A Versatile Opportunistic Pathogen

• Oral ____

____

____

____

____

____

____ rash

____ foot

A Versatile Opportunistic Pathogen • Oral candidiasis  Vaginitis  Onchomycosis  Esophagitis  Endocarditis  Keratitis  Diaper rash  Athlete’s foot

23

Oral Candidiasis 

___ ___s • Thrush

____ ____s • Denture stomatitis • HIV related

___ ___is • Corners of the mouth

___ ___ ____is • candidal leukoplakia

____ ____ ____

Oral Candidiasis  Pseudomembranous candidiasis • Thrush  Erythematous candidiasis • Denture stomatitis • HIV related  Angular cheilitis • Corners of the mouth  Chronic hyperplastic candidiasis • candidal leukoplakia  Chronic mucocutaneous candidiasis

24

Host factors in the Oral Cavity

All these oral manifestations have corresponding __ ___ bc candida is commensal

Host factors in the Oral Cavity All these oral manifestations have corresponding host factor bc candida is commensal

25

1-Pseudomembranous candidiasis  AKA____

 Creamy__ __s (pseudomembranes)

• ____l cells

• Yeast ____

• Can occur on the surface of the ___ ___ ____ ___ ____

______ wiped off to leave ___ ___underneath

• Not ___g tissue, just growing on the ____

• Common Causes of Thrush

– Newborn babies → Not emergency

- Immature ___ ___

- Immature ___ ___

- Pacifier can get contaminated

- Resolves __ ___

– Older adults →indicates an underlying issue

- Poor___ limitation

- Local __ ___ (e.g. steroid____ for asthma)

- Underlying ___ ___

1-Pseudomembranous candidiasis  AKA Thrush  Creamy-white plaques (pseudomembranes) • Mucosal cells • Yeast overgrowth • Can occur on the surface of the tongue, soft palate, cheek, gingivae or pharynx  Easily wiped off to leave red areas underneath • Not invading tissue, just growing on the surface • Common Causes of Thrush – Newborn babies → Not emergency - Immature immune system - Immature oral flora - Pacifier can get contaminated - Resolves by itself – Older adults →indicates an underlying issue - Poor nutritional limitation - Local immune suppression (e.g. steroid inhaler for asthma) - Underlying systemic disease

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2-Erythematous candidiasis 

Most ___ form of oral candidiasis 

____wearers 

Called___ ____

  ___% of denture wearers

____ infection

 Seen in HIV+ status before medication.  Early sign o___ __

 After ____ use 

Red areas of ____ size

 Any part of the____ ____

 Lesions may be___

 On tongue may have marked_____

2-Erythematous candidiasis  Most common form of oral candidiasis  Denture wearers  Called Denture stomatitis  65% of denture wearers  HIV+ infection  Seen in HIV+ status before medication.  Early sign of developing HIV  After antibiotic use  Red areas of varying size  Any part of the oral mucosa  Lesions may be painful  On tongue may have marked de-papillation

27

Denture Stomatitis 

Candida can biofilm on __ ___ • Oral prosthesis • Medical catheters 

Poor __ ___

 Poor__ ___

____n of dentures in the mouth overnight

Denture Stomatitis  Candida can biofilm on synthetic material • Oral prosthesis • Medical catheters  Poor oral hygiene  Poor denture hygiene  Retention of dentures in the mouth overnight

28

3-Chronic hyperplastic candidosis

Candida ____

 

____ lesions on the oral mucosa of the ___ or on the surface of the ___

• ____  or ____

The white patches ____ be rubbed off

 Common in__-age ___ ____

  Can be mistaken for___h. Look similar.

 Get____  (raised lesions) in surface of the mouth  Can form o___ ny soft tissue in mouth

3-Chronic hyperplastic candidosis  Candidal leukoplakia  White lesions on the oral mucosa of the cheek or on the surface of the tongue • Smooth or Nodular  The white patches cannot be rubbed off  Common in middle-aged male smokers  Can be mistaken for thrush. Look similar.  Get nodules (raised lesions) in surface of the mouth  Can form on any soft tissue in mouth

29

Candidal leukoplakia 

Can’t be wiped off because here they form the____

 Hyphae have penetrated down int ___ ___

 Epithelium is__ ___ and____

 o Surfaces become hyperplastic. o Get a lot of __ ___and divison but cells are __ __

o Build up dead cells that don’t come off.

o That appearance of nodules is from yeast hyphae and dead cells

 The cause of cell proliferation is____ r o Don’t know if yeast cause it or they just enjoy living on these dead cells. 

Candidal hyphae invade the _____ layer

 Lesions that are untreated are at risk of becoming____

____  antifungals o If you leave those lesions there, they are at increased risk of becoming cancerous. o Early sign of oral cancer. o Has to be treated. o Don’t wait to see if it goes away. o May try to___ off dead tissue or ___ remove it

Candidal leukoplakia  Can’t be wiped off because here they form the hyphae  Hyphae have penetrated down into epithelial surface  Epithelium is para-keratinized and hyperplastic o Surfaces become hyperplastic. o Get a lot of cell growth and divison but cells are not shedding o Build up dead cells that don’t come off. o That appearance of nodules is from yeast hyphae and dead cells  The cause of cell proliferation is unclear o Don’t know if yeast cause it or they just enjoy living on these dead cells.  Candidal hyphae invade the parakeratinized layer  Lesions that are untreated are at risk of becoming cancerous  Topical antifungals o If you leave those lesions there, they are at increased risk of becoming cancerous. o Early sign of oral cancer. o Has to be treated. o Don’t wait to see if it goes away. o May try to laser off dead tissue or surgically remove it

30

4-Angular cheilitis  Areas of inflammation at the____s of the mouth

 Saliva ___ in mucosal ___

 May be___y-microbial with ___ bacteria • Staphlococcus ____

 Common in • ___rs •___, ___a (difficulty swallowing) • Patients with other forms of ____ (high levels of oral Candida)

Usually____ manifestation of other oral infection

A lot of time, its saliva related. Difficulty swallowing, drooling

4-Angular cheilitis  Areas of inflammation at the angles of the mouth  Saliva trapped in mucosal folds  May be poly-microbial with skin bacteria • Staphlococcus aureus  Common in • Smokers • Elderly, dysphagia (difficulty swallowing) • Patients with other forms of candidiasis (high levels of oral Candida) Usually secondary manifestation of other oral infection A lot of time, its saliva related. Difficulty swallowing, drooling