2_ Isolation and Enumeration of Yeast and Molds

unicellular state

Yeasts are fungi which exist predominantly or solely in a ___

indispensable

Likewise, yeasts and molds are ___microorganisms in several fermentation processes involved in making bread, beer, and wine

true mycelium or pseudomycelium

Some yeasts are capable of forming ___

Pseudomycelium

____ false mycelium or sprout mycelium) is a mycelium-like structure consisting of chains of cells formed by sequential budding (sprouting)

sequential budding (sprouting)

Pseudomycelium (false mycelium or sprout mycelium) is a mycelium-like structure consisting of chains of cells formed by ___

reduced oxygen conditions

Pseudomycelium can be demonstrated when yeasts are grown under ____.

true mycelium

A ____is a vegetative structure that gives rise to arthrospore or blastospore in some species of yeasts.

vegetative structure

A true mycelium is a ___that gives rise to arthrospore or blastospore in some species of yeasts.

arthrospore or blastospore

A true mycelium is a vegetative structure that gives rise to ___ in some species of yeasts.

arthrospore

An ___ is an asexual spore (conidium) formed from a preexisting hypha.

preexisting hypha

An arthrospore is an asexual spore (conidium) formed from a __

conidium

An arthrospore is an asexual spore (___) formed from a preexisting hypha.

blastospore

___is still an asexual spore formed following the marked enlargement of a part of a cell before separation by a septum

separation by a septum

blastospore is still an asexual spore formed following the marked enlargement of a part of a cell before ___

budding, fission, or as mycelia consisting of septate hyphae

Reproduction by yeasts is mainly by asexual means such as b

budding

an outgrowth develops from the parent cell and eventually separates as a daughter cell.

fission

In ___ the parent cell simply divides and develops into two identical daughter cells.

ascospore or basidiospore

Sexual reproduction in yeasts, if it occurs, is usually by ___ formation and some are anamorphic (imperfect), lacking sexual phase or have not yet discovered/established.

anamorphic (imperfect)

Sexual reproduction in yeasts, if it occurs, is usually by ascospore or basidiospore formation and some are____, lacking sexual phase or have not yet discovered/established.

molds

___are filamentous or multicellular fungi that are commonly found as contaminants from the air, and as constituents of the normal flora in nature

hyphae

Molds grow as filaments called ___ which are collectively called mycelia.

mycelia

grow as filaments called hyphae which are collectively called ___.

branched or unbranched

The hyphae of molds that make up the thallus (body/vegetative structure) of the mold can be either____

discernible crosswalls (septa)

Moreover, the mycelium can also be either septated or non-septated depending on the presence or absence of ____ between individual cells.

Crosswalls

___have small pores through which the cytoplasm is continuous throughout the hyphae to allow exchange of cytoplasm or organelles.

immediately behind a septum

In septated fungi, branches are often situated ___

coenocytic or multinucleated

Non-septated hypha tends to be continuous along the whole length of the filament that can be either ____

dematiaceous

Molds that possess melanin pigments in their cell walls are described as ___ resulting to dark pigmentation of the colonies.

hyaline

On the other hand, molds that do not produce pigments in their cell walls are described as ___ (transparent or translucent)

submerged, aerial, or fertile

The mycelia can be differentiated as ____ mycelia

Submerged mycelia

are those that penetrate and anchor the thalli in the substrate and absorb the 2 nutrients.

Aerial mycelia

___are those that grow above the substrate.

Fertile mycelia

___are aerial mycelia that bear the reproductive structures such as conidia or sporangia

conidia or sporangia

Fertile mycelia are aerial mycelia that bear the reproductive structures such as ___

Sporangiospores

• These spores are initially enclosed but are released when the sporangium ruptures.

• ___are spores that form within a sac called a sporangium

sporangiophores

The sporangia are attached to stalks called ___

sporangium

Sporangiospores are spores that form within a sac called a ____

conidiophores

• Are free spores not enclosed by a spore-bearing sac.

• conidia are spores that form on specialized hyphae called ___

conidia

___are spores that form on specialized hyphae called conidiophores

microconidia

If the conidia are small, they are called ____

macroconidia

Large multicellular conidia are known as _____

P.B.A.C

(phialospores, blastospores, arthrospores, chlamydospores)

There are four types of conidia:

phialospores

conidia are produced by vase-shaped cells called phialides

blastoconidia

conidia are produced from budding of preexisting conidia

arthrospores

conidia formed by separation from preexisting hyphal cells

chlamydospores

spores are large, thick walled, round, or irregular structures formed within or on the ends of a hypha

union of compatible nuclei

Sexual reproduction in molds involves the _____

O.Z.A.B

(oospores, zygospores, ascospores, basidiospores)

mold sexual spores result from a mating between two different organisms or hyphae which include the:

oospores

Mold sexual spores: produced when male gametes enter a large spherical cell called oogonium and fertilized the egg within

zygospores

Mold sexual spores: formed by union of two h protrusions from neighboring hyphae of two different strains

ascospores

Mold sexual spores: produced enclosures, which may be oval sacs or elongated tubes called asci

basidiospores

Mold sexual spores: produced externally on club-shaped bodies called basidia

FUNGI

• Heterotrophs - saprophytic, parasitic (biotrophs), and symbiotic (either commensals or mutuals).

• Can either be unicellular or multicellular.

• Possess a cell wall that is made up of chitin

Yeasts

• refers to a microscopic fungus, consisting of a single, oval cell

• Very common in the environment

• Oval in shape, and is colorless and smooth

• Converts carbohydrates to alcohol during fermentation

• Reproduces through budding

• Used in baking industry and in the production of ethanol

• Example: Saccharomyces cerevisiae and Cryptococcus neoformans

Molds

• refers to a growth form of fungus, which grows in the form of multicellular filaments called hyphae

• Found in damp, dark, or steam-filled areas

• Has a fuzzy appearance; colors can be green, orange, black, brown, purple, and pink

• Secretes hydrolytic enzymes to external food sources and absorbs nutrients

• Reproduces through either sexual or asexual spores

• Used in the production of cheese

• Example: Mucor, Penicillium, Rhizopus, and Aspergillus

PLASMOGAMY

Sexual reproduction in fungi:

• fusion of cytoplasm

KARYOGAMY

Sexual reproduction in fungi:

• the fusion of nuclei

MEIOSIS

Sexual reproduction in fungi:

• production of haploid spores (n). Sexual reproduction results in the formation of specialized spores such as zygospores, ascospores, and basidiospores