PRELIM: INTRODUCTION TO MYCOLOGY Flashcards by Chin Lys

Mykos

fungus

How well did you know this?

Not at all

Perfectly

Logus

study

How well did you know this?

Not at all

Perfectly

Study of fungi

Mycology

How well did you know this?

Not at all

Perfectly

Branch of biology concerned with the study of fungi, including their biochemical, physical and microscopic properties, their use to humans and as well as the human diseases they can cause, such as toxin production or infection

Mycology

How well did you know this?

Not at all

Perfectly

is the study of fungi that produce pathology or disease in humans and animals including their ecology and epidemiology

MEDICAL MYCOLOGY

How well did you know this?

Not at all

Perfectly

is the study of the general characteristics, pathology & pathogenesis, and laboratory tests & methods of medically important fungi that aids in their identification and treatment

DIAGNOSTIC MYCOLOGY

How well did you know this?

Not at all

Perfectly

Fungi – exist in two forms:

Molds
Yeasts

How well did you know this?

Not at all

Perfectly

Fungi can exist as in mold form only or yeast
form only or having both forms. T OR F

How well did you know this?

Not at all

Perfectly

Eukaryotic

Fungi

How well did you know this?

Not at all

Perfectly

With membrane-bound nucleus, organelles, 60s-40s ribosomal subunits, etc.

Fungi

How well did you know this?

Not at all

Perfectly

Fungi

Contains chitin in their cell walls:

Peptidoglycan for bacteria
Cellulose for plants

How well did you know this?

Not at all

Perfectly

Contains chitin in their cell walls

Fungi

How well did you know this?

Not at all

Perfectly

Can be single-celled (yeast) or multicellular (mold )

Fungi

How well did you know this?

Not at all

Perfectly

Can reproduce sexually or asexually (produce spores)

Fungi

How well did you know this?

Not at all

Perfectly

the characteristic of fungi that differ it from plants (autotrophs); heterotrophs depend on other organisms as their source of nutrients.

Heterotrophs

How well did you know this?

Not at all

Perfectly

HETEROTROPHIC ORGANISM CAN BE:

Saprophytic
Symbiotic
Parasitic

How well did you know this?

Not at all

Perfectly

feeds on dead organic material (ex: mushrooms growing on dead trees)

Saprophytic

How well did you know this?

Not at all

Perfectly

fungi living in another organism and causes harm to the latter.

Parasitic

How well did you know this?

Not at all

Perfectly

Fungi that are responsible for breaking down and recycling dead plant and animal materials

SAPHROPHYTIC FUNGI

How well did you know this?

Not at all

Perfectly

fungi is living together with other organisms and establishes mutualism; will not particularly cause disease or any harm

Symbiotic

How well did you know this?

Not at all

Perfectly

Example: Mushroom growing on dead trees/animal bodies

SAPHROPHYTIC FUNGI

How well did you know this?

Not at all

Perfectly

SYMBIOTIC FUNGI:

MYCORRHIZA

How well did you know this?

Not at all

Perfectly

Mycorrhizae fungi germinates in soil.

SYMBIOTIC FUNGI: MYCORRHIZA

How well did you know this?

Not at all

Perfectly

Its hyphae penetrate the roots of the plant.

SYMBIOTIC FUNGI: MYCORRHIZA

How well did you know this?

Not at all

Perfectly

The plant roots provide essential nutrients for the growth of the fungi.

SYMBIOTIC FUNGI: MYCORRHIZA

In return, the large mass of fungal hyphae acts as a virtual root system for the plants, ncreasing the amount of water and nutrients that the plant may obtain from the surrounding soil.

SYMBIOTIC FUNGI: MYCORRHIZA

- depends on environment - can be yeast or mold

DIMORPHIC FUNGI

# * only ____ spp. generally recognized as causes of disease in humans

100-150 spp.

accidental hosts by spores inhalation or introduction via trauma

humans

healthy humans are relatively resistant to infection of fungi except for dimorphic fungi. T OR F

no cellulose (has hypae/roots)

fungi

has cellulose

plants

# * Fungi that attack living organisms,penetrate their outer defenses, invade them. And obtain nourishment from living cytoplasm, thereby causing disease and so metimes death of the host.

PARASITIC FUNGI

________infiltrating their bodies and minds Cordyceps spore can manipulate the Bullet ant then erupts from the ant’s head

Bullet Ants with spores from (parasitic fungus)

# * 2 FORMS OF FUNGi:

- yeast - mold

UNICELLULAR Grow at body temperature (37 C)

YEAST

Moist, creamy, opaque, pasty colonies

YEAST

MULTICELLULAR Grow best at room temperature (22-25 C)

MOLD

Fluffy, cotonny, woolly, powdery colonies

MOLD

Unicellular

YEAST

Oval, Spherical

YEAST

Oval, Spherical

YEAST

Parasitic

YEAST

Facultative anaerobe

YEAST

Multicellular

MOLD

Filamentous

MOLD

Room Temp

MOLD

Saphrophytic

MOLD

Aerobic

MOLD

multicellular with tubualr, filamentous hyphae (branches)

MOLD

any organic environment having a moist/humid atmosphere and not exposed to harsh weather conditions

MOLD

production of sexual or axesual, airborne spores

MOLD

threadlike, come in a wide variety of colors and hues

MOLD

mostly unicellular and existing individually or with buds growing on them

YEAST

mostly occur naturally in oceans

YEAST

budding or binary fission

YEAST

round or oval-shaped, dull colored and mostly monochromatic

YEAST

Unicellular circular, spherical or oval-shaped forms of fungi

YEAST

# * Colonies are moist, pasty, creamy and opaque

YEAST

Yeasts are less colorful compared to molds, some yeast colonies can be pigmented

YEAST

May be mistaken as bacterial colonies

YEAST

Yeast colonies should be biochemically differentiated from bacterial colonies

YEAST

YEAST Optimum temperature:

near body temperature (37 C)

Parasitic

YEAST

form of fungi that can develop disease in human

Parasitic

Appears to be “multicellular” but just undergoing process of Budding.

BUDDING

Most of the clinical specimen processed in the laboratory are in YEAST form. T OR F

Multicellular

MOLDS

Mold Colonies appearing to be Filamentous or Cotton

MOLDS

Branching form

MOLDS

“Hyphae”

Branches

MOLDS Optimum temperature for growth:

Room temperature (35- 37 C)

Saprophytic

MOLDS

called such because they can survive outside the human body; can rely on dead plants/animals as source of nutrients

Saprophytic

Ability that fungi can exist in the form of both mold and yeast.

DIMORPHISM

This is usually brought about by change in temperature

DIMORPHISM

EXAMPLE OF DIMORPHISM

Histoplasma Blastomyces Coccidioides (not thermally dimorphic) Paracoccidiodes Sporothrix (Subcutaneous) Penicillium

SPOROTHRIX SCHENCKI

Acquired via: accidental pricking of the skin by the rose thorn

SPOROTHRIX SCHENCKI

Skin nodule ( subcutaneous tissue) bipsy will demonstrate yeast cell

SPOROTHRIX SCHENCKI

optimum temperature of growth for saprophytes (mold) is ____ and _______ for parasite fungi (yeast)

20-30 C; 30-37 C

The standard temperature for incubation of fungi is ____ and cultures should be incubated in a humidified environment for ____. While Bacterial cultures require incubation temperature of _____

30ºC 21 days 37 degree Celsius

grow best at pH of **4-6**; average of 5.0

Fungi

are more resistant to osmotic pressure than bacteria

Fungi

requires less nitrogen and moisture than bacteria

Fungi

can be aerobic or anaerobic

Fungi

are capable of metabolizing complex carbohydrates such as **lignin** in wood.

Fungi

# * what percent is **lignin** in woods?

15-25%

are aerobic

Molds

are facultative anaerobes

Yeasts

# * HARMFUL EFFECTS OF FUNGI

1. ALLERGY 2. MYCOSES 3. MYCOTOXICOSES

Spores are potent triggers of allergic reactions

ALLERGY

Mold spores get into your nose and can cause allergy symptoms.

ALLERGY

Mold form of a fungi with asexual spores at the tip released on the air new fungi.

ALLERGY

- Some spores of molds can trigger allergic reactions (Allergic rhinitis or asthma attacks)

ALLERGY

a direct fungal infection of animals, including humans

MYCOSES

Fungi causing infection in any parts of the body.

MYCOSES

Fungi directing one specific tissue, location or organ in the body.

MYCOSES

Disease cause by the natural toxin produced by fungi

MYCOTOXICOSES

# * No presence of fungi in the affected tissue or organ. What causes the disease is the toxin produced by the fungi.

MYCOTOXICOSES

EXAMPLE OF MYCOTOXICOSES

Aspergillus flavus

can produce aflatoxin that can cause hepatocellular carcinoma (seen in both children and adults)

Aspergillus flavus

Aflatoxin, once ingested in large amount, causes in children:

o Neurological problem o Stunted growth

# * BENEFICAIL EFFECTS OF FUNGI

1. PREPARATION OF BREAD 2. ALCOHOLIC FERMENTATION 3. PREPARATION OF VACCINE 4. SOURCES OF DRUGS 5. FOOD 6. RECYCLING OF ORGANISC MATTER 7. MAINTAIN ECOLOGICAL BALANCE

Yeast cells are used in preparation of bread

PREPARATION OF BREAD

Bread = sugar + gluten + yeast cells + water

PREPARATION OF BREAD

# * Gluten forms the framework of bread

PREPARATION OF BREAD

Yeast converts the sugar into carbon dioxide

PREPARATION OF BREAD

Yeast cells are used in induce alcoholic fermentation in grape juice/ barley grain to produce wine and beer; respectively

ALCOHOLIC FERMENTATION

“Say YEAST to beer and wine”

very true

Human hepatitis B virus vaccine is prepared using antigen produced by recombinant technology in yeast (Saccharomyces)

PREPARATION OF VACCINE

Get the DNA that encodes for the surface antigen incorporate the viral DNA to the yeast cells Yeast cell will now have the capacity to produce the surface antigen. Yeast cell produce ßßby budding Extract as Vaccine

RECOMBINANT TECHNOLOGY

Penicillin sources:

Penicillium notatum

# * used against gram+ bacteria. clinically it aginst pneumonia, rheumatic fever, tonsillites, tetanus, diptheria and many other diseases

penicillin

griseofulvin sources:

Penicillium griseofulvum

used against mycosis

griseofulvin

cephalosporin sources:

Cephalosporium acremonium (a marine fungus)

used against gram+ and gram- bacteria; typhoid

cephalosporin

who discoverd Penicillin?

Alexander Flemming

Higher fungi may be eaten directly as mushrooms

FOOD

Saprophytic fungi in soil produce degradative enzymes essential for the biologic recycling of organic matter

RECYCLING OF ORGANISC MATTER

Parasitic fungi can also help regulate the number of other species to maintain ecological balance

MAINTAIN ECOLOGICAL BALANCE

Primarily a saphrophytic fungi but if the environment where it is living is low in NITROGEN = transform into parasitic fungi

Arthrobotrys conoides

using hyphae to form loops that are motion-sensitive. Whenever a nematode passes thru the loops will constrict trapping the nematode and then produce enzymes that will eventually invade the surface of the nematode and kill and digest it.

Arthrobotrys conoides

Unicellular form of fungi

YEAST

Spherical or elliptical in shape

YEAST

YEAST Reproduces by:

1. Budding – most common 2. Binary fission 3. Formation of pseudohyphae

Parent yeast cell dividing equally.

BINARY FISSION

-Daughter cell (Blastosphore or Blastoconidia) is smaller than parent yeast cell.

BUDDING

-Most common way of reproduction among yeast cell.

BUDDING

Asymmetric division of yeast cells

BUDDING

A new yeast cell (blastospore) is formed through mitotic cell division and remains attached as a bud on the old cell until it splits and becomes independent.

BUDDING

# * A yeast cell duplicates its genetic material, or deoxyribonucleic acid (DNA), and then divides into two parts (cytokinesis), with each new organism receiving one copy of DNA.

BINARY FISSION

“ FALSE HYPHAE “

PSEUDOHYPAHE

Buds fail to detach producing elongated yeast cells

PSEUDOHYPAHE

- found yeast - always arise from a constricted area

pseudohyphae

- root-like structures found in molds - elongated structure arising form a non-constricted area

hyphae

Consist of branching cylindrical tubules with diameter called hyphae

MOLD

Hyphae grow to form a filamentous mass of intertwining strands called a mycelium

MOLD

MOLD COLONIES 2 PORTIONS:

* reproductive/aerial hyphae * vegetative portion

grow on the top of the agar's surface of the culture media

reproductive/aerial hyphae

contains the reproductive structures such as spores

reproductive/aerial hyphae

portion of the mycelium that anchors the mold and absorbs nutrients

vegetative portion

grows in or on a substrate and absorbs water

vegetative portion

another name of vegetative portion

thallus

# 1. can be septate or nonseptate.

HYPHAE

have dividers between the cells, called septa (singular septum).

SEPTATE

# * The septa have openings called pores between the cells, to allow the flow of cytoplasm and nutrients throughout the mycelium.

SEPTATE

Its septate and not septated.

SEPTATE

Nonseptate or Coenocytic hyphae

NONSEPTATE

- lack septum and cell membranes between the cells.

NONSEPTATE

Septa can be seen in branching points

NONSEPTATE

NONSEPTATE EXAMPLE

Zygomycetes: Mucor, Rhizopus, Absidia

Nonseptated Hyphae:

Mucor, Rhizopus, Absidia

no rhizoids

Mucor

Nodal rhizoids

Rhizopus

Internodal

Absidia

root-like structures attached to the nonseptated hyphae.

Rhizoids

Long stalk arising from nonseptated hyphae

Sporangiophore

dilated part of sporangiophore; serve as source of nutrients of the spores

Columella

sack that contains the spores

Sporangium

spores produced within a sack

Sporangiospore

Hyaline if fungal structures are colorless

HYPHAE

Highly refractile

HYPHAE

are group of fungi that produce melanin in their cell walls, giving them a characteristic brown colour when grown on agar

Dematiaceous

Agents causing Chromoblastomycosis

DEMATIACEOUS FUNGI

Group of fungi with dark colonies and pigmented fungal elements

DEMATIACEOUS FUNGI

# DEMATIACEOUS FUNGI Curvularia

Curvularia Alternaria Phialophora Exophiala

# * An extracellular layer which lies outside the cell wall and it is usually composed of polysaccharides.

CAPSULE

It protects the cell from different environmental dangers such as phagocytosis, desiccation and harmful chemicals

CAPSULE

Capsule of ________ has antiphagocytic properties and is associated with virulence.

Cryptococcus neoformans

Cryptococcus neoformans can cause ________ among immunocompromised patients

Fungal meningitis

Boundary of the cell (innermost outermost layer):

cell membrane > cell wall > Capsule

Most common cause of Fungal meningitis:

Cryptococcus neoformans

Abundant in: eucalyptus tree and pigeon droppings

Cryptococcus neoformans

Immunocompromised patient not be able to eliminate the spores

Cryptococcus neoformans

Used to identify the capsule of Cryptococcus neoformans

INDIA INK STAINING / INDIA INK WET MOUNT

is directly examined by adding one drop of India ink.

CSF

Capsule appear as a _______ against a dark background (negative staining). in india ink

clear halo

CSF centrifuged to let capsule to form sediment to be stained:

sediment

to stain everything in the slide except the capsule of Cryptococcus neoformans (+:white halo against black background)

India ink

White Capsule against a black background

Negative Staining

Used for: isolation of Cryptococcus neoformans (brown or dark brown color)

BIRD SEED AGAR

Candida albicans color:

colorless

The cell wall is a characteristic structure of fungi and is composed mainly of glucans, chitin and mannan.

CELL WALL

As the components of the fungal cell wall are not present in humans, this structure is an excellent target for antifungal therapy

CELL WALL

CELL WALL COMPOSED OF:

1. Chitin 2. Glucans 3. Mannan

forms the cross-linking

Glucans

topmost

Mannan

MOLDS FUNGAL CELL WALL MAJOR COMPONENT:

Chitin (polymers of N- acetylglucosamine)

YEAST FUNGAL CELL WALL MAJOR COMPONENT

Glucan (polymers of glucose)

Human Cell Membrane: main sterol is

Cholesterol

provides stability and flexibility to cell membrane

Fungi: Ergosterol

# * Bilayered membrane composed of several phospholipids

CELL MEMBRANE

Contain sterols which are essential for the viability of fungi

CELL MEMBRANE

Nuclei, mitochondria, ER, storage vacuoles containing hydrolytic enzymes, ions, metabolites such as amino acids

CELL MEMBRANE

Principal fungal sterol is

ergosterol

fungal cell wall is poorly stained with routine hematoxylin and eosin. T OR F?

LABORATORY IDENTIFICATION OF FUNGI

 Microscopic Methods (recommended)  Cultivation (recommended)  Biochemical tests  Serologic Test

quick & simple method to visualize budding yeasts, hyphae, & pseudohyphae. Lack of contrast is a major disadvantage making it difficult to appreciate fungal elements microscopically.

Saline Mount

MICROSCOPIC METHODS WET MOUNT:

1. saline mount 2. potassium hydroxide (KOH) mount 3. calcoflour white stain 4. lactophenol cotton blue (LPCB) 5. giemsa or wright stain 6. periodic acid-schiff (PAS) 7. methenamine-silver nitrate stain

rapid & simple technique

Potassium Hydroxide (KOH) Mount

KOH acts as clearing agent:

o Dissolves keratin o Eliminates debris o Dissolves fat droplets (may appear as yeast cells)

is used for nails (highly keratinized tissue)

20% KOH

# * Although ca also result to poor contract like saline mount. Used to visualize budding yeasts, hyphae, & spherules.

Potassium Hydroxide (KOH) Mount

Can also be used to examine hair to determine whether hair is infected within the shaft (ENDOTHRIX INFECTION) or hair is infected outside the hair shaft (ECTOTHRIX INFECTION)

Potassium Hydroxide (KOH) Mount

used as a brightening agent since calcoflour white BINDS to CHITIN in the fungal cell wall which provides excellent contrast over a dark background when visualized using a fluorescent microscope.

Calcoflour White Stain

used to vIsualize fungal structure by staining chitin in the fungal cell wall color BLUE.

Lactophenol Cotton Blue (LPCB)

Also useful in staining tease preparation (wet mount) or slide cultures

Lactophenol Cotton Blue (LPCB)

# * kills other organisms (bacteria)

Phenol

preserves fungal elements

Lactic Acid

stains the chitin in the fungal cell wall blue.

Cotton Blue

Advantages: - Structures are readily seen microscopically - Has GLYCERINE component – slows down The drying of the LPCB

Lactophenol Cotton Blue (LPCB)

used to visualize intracellular Histoplasma capsulatum in blood smears, lymph nodes, lung, liver, or bone marrow. The organism appears as small, oval yeast cell staining light to dark blue.

Giemsa or Wright Stain

also stains well using this method (GIEMSA STAIN) result to “ SUNBURST APPEARANCE"

Cryptococcus neoformans

Giemsa or Wright Stain: demonstrates budding while bacteria equal circle

Candida albicans

used to stain the hypha of moulds and some yeasts. Periodic Acid oxidizes the OHin the cell wall CHO to form aldehydes which reacts with the basic fuchsin dye to form a pink-purple complex. A counterstain (fast green) can be used to provide Contrast

Periodic Acid-Schiff (PAS)

useful for screening of clinical specimens for presence of fungal elements which stains black. Fungi appear outlined in black against a pale-black ground.

Methenamine-Silver Nitrate Stain

is a modification of this method used for histological examination of specimens

GOMORI METHENAMINE-SILVER NITRATE STAIN

● Wood’s lamp (UV light) ● Emits wavelength 320–450 nm (peak 365 nm) ● The light is held over an area of skin in darkened room. ● Infected hair and skin will fluoresce when examined in the dark

FLUORESCENCE TEST

Culture media must include sources of:

1. Nitrogen 2. Nitrate 3. Amino acids 4. Carbon 5. Vitamins and minerals

Has a low pH which can inhibit growth of bacteria

SABOURAUD DEXTROSE AGAR

PRIMARY ISOLATION MEDIA:

1. sabouraud dextrose agar 2. brain heart infusion media 3. mycosel - SDA-CC

Used for isolation of most fungi

SABOURAUD DEXTROSE AGAR

# * Disadvantages ~ May not allow yeast phase of the fungi to grow ~ Too many fungi (including saprophytes) can grow on the agar ~ Histopasma capsulatum fails to grow in this medium

SABOURAUD DEXTROSE AGAR

Recommended for the culture of yeast phase of dimorphic fungi at 35-37 degree Celsius

BRAIN HEART INFUSION MEDIA

Made from pig heart and calf brain

BRAIN HEART INFUSION MEDIA

Antimicrobial supplements

MYCOSEL - SDA-CC

inhibit contaminating saprophytic fungi

Cycloheximide

inhibit gram bacterial growth

Chloramphenicol

Chloramphenicol can be substituted with Gentamicin or Tetracycline

MYCOSEL - SDA-CC

DIFFERENTIAL/ SPECIAL ISOLATION MEDIA:

1. potato dextrose agar (PDA) 2. corn meal tween 80 agar (CMT 80) 3. dermatophyte test medium (DTM) 4. christensen urea slant

used as a subculture medium rather than a primary isolation medium. This medium enhances the sporulation & pigmentation of fungi

Potato Dextrose Agar (PDA)

used for the demonstration of blastoconidia, pseudohyphae, arthroconidia, and chlamydospores in Candida spp. and some other yeasts

Corn Meal Tween 80 Agar (CMT 80)

used for the selective growth of dermatophytes. This medium will turn from yellow to red within 14 days incubation at room temperature if dermatphytes are growing. It should be checked once every week

Dermatophyte Test Medium (DTM)

used to detect urease production by turning the slant to pinkish purple color after 48 hours incubation.

Christensen UREA Slant

Christensen UREA Slant UREASE POSITIVE (+):

Trichosporon, Rhodotorula, & Cryptococcus

Christensen UREA Slant UREASE NRGATIVE (-):

Geotrichum, Saccharomyces, & most Candida spp

IMPORTANT BIOCHEMICAL TEST FOR THE IDENTIFICATION OF YEAST & YEAST LIKE ORGANISM

1. Carbohydrate (CHO) Fermentation 2. Carbohydrate (CHO) Assimilation 3. Nitrogen Assimilation 4. Germ Tube Test (Reynold’s Brande Phenomena)

Principle: growth and utilization of CHO under anaerobic conditions as determined by acid & gas production

Carbohydrate (CHO) Fermentation

Carbohydrate (CHO) Fermentation Indicator:

Bromcresol Purple (BCP)

Carbohydrate (CHO) Fermentation Positive Reaction:

Yellow Color for Acid production and bubbles trapped in the fermentation tube for gas production

NOTE: Observe every 48 hours for 14 days

Carbohydrate (CHO) Fermentation

Principle: the yeast ‘s ability to utilize a particular CHO is determined by using a CHO-free (nitrogen-based) agar and filter paper disks that are impregnated with various CHO. Growth around the disk indicates the yeast can utilize the CHO

Carbohydrate (CHO) Assimilation

Carbohydrate (CHO) Assimilation Positive Reaction:

growth around the disk indicates the CHO has been assimilated by the yeast

NOTE: Incubate plate for 24 hours at 300C. Plates should be re-incubated for another 24 hours and read again if the growth is insufficient.

Carbohydrate (CHO) Assimilation

Principle: Nitrate assimilation is defined simple as the utilization of a nitrogen source by a microorganism in the presence of oxygen. A positive reaction is indicated by the presence of growth or the use of a pH indicator in medium. The indicator method is a modification of the Wickerham method that was devised by Adams and Cooper

Nitrogen Assimilation

Nitrogen Assimilation Indicator:

Bromthymol Blue (BTB)

Nitrogen Assimilation Positive Reaction:

Green to Blue Slant due to alkaline pH when nitrate is assimilated.

NOTE: Incubate aerobically with loosen caps at 35-370C for 24-72 hours.

Nitrogen Assimilation

a screening procedure which is used for the identification and differentiation of Candida albicans from other yeasts.

Germ Tube Test (Reynold’s Brande Phenomena)

Principle: This test allows the detection of the Germ Tubes which are the initial stage of hyphae formation. These are the short, non septate germinating hyphae which are one half the width and three to four times the length of the yeast from which they originate. Approximately 95-97% of Candida albicans isolate develop germ tube when incubated in a proteinaceous media at 35C for 2.5-3 hour

Germ Tube Test (Reynold’s Brande Phenomena)

PRELIM: INTRODUCTION TO MYCOLOGY Flashcards

(252 cards)