Morphology of Yeasts and Molds Flashcards
1
Q
other name for pseudomycelium
A
false mycelium or sprout mycelium
2
Q
Pseudomycelium can be demonstrated when yeasts are grown under reduced ___conditions
A
oxygen
3
Q
is a chain of cells that resemble a small mycelium
A
pseudomycelium
4
Q
Yeast reproduces by ____.
A
budding
5
Q
Sometimes a bud starts forming a new bud before separating from the parent cell.
This results in the formation of branched or unbranched chains of buds, called
A
pseudomycelium
6
Q
is a vegetative structure that gives rise to arthrospore or blastospore.
A
true mycelium
7
Q
is an asexual spore (conidium) formed from a preexisting hypha.
A
arthrospore
8
Q
is still an asexual spore formed following the marked enlargement of a part of a cell before separation by a septum
A
blastospore
9
Q
Reproduction by yeasts is mainly by asexual means such as by
A
budding
fission
mycelia consisting of septate hyphae
10
Q
an outgrowth develops from the parent cell and eventually separates as a daughter cell.
A
budding
11
Q
the parent cell simply divides and develops into two identical daughter cells.
A
fission
12
Q
seexual reproduction, if it occurs, is usually by
A
ascopore
basidiospore
13
Q
some spores are ___ (imperfect), lacking sexual phase or have not yet discovered/established
A
anamorphic
14
Q
are filamentous or multicellular fungi that are commonly found as contaminants from the air, and as constituents of the normal flora in nature.
A
molds
15
Q
molds grow as filaments called
A
hyhpae
16
Q
hyphae is collectively called
A
mycelia
17
Q
vegetative structure of mold
A
thallus
18
Q
he hyphae that make up the thallus (body/vegetative structure) of the mold can be either
A
branched
unbranched
19
Q
___branching of the hyphae is uncommon, but does exist in a few species
A
dichotomous
20
Q
Dichotomous branching of the hyphae is uncommon, but does exist in a few species like in what speies
A
allomyces
galactomyces geotrichum
21
Q
Moreover, the mycelium can also be either be
A
septated
non-septated
22
Q
discernible crosswalls
A
septa
23
Q
Crosswalls have small ___ through which the cytoplasm is continuous throughout the hyphae to allow exchange of cytoplasm or organelles.
A
pores
24
Q
Crosswalls have small pores through which the cytoplasm is continuous throughout the hyphae to allow
A
exchange of cytoplasm
organelles
25
. In septated fungi, branches are often situated immediately behind a ___.
septum
26
Non-septated hypha tends to be continuous along the whole length of the filament that can be either ____ or ___
coenoycyic
multinucleated
27
Since the hypha is a structural unit, the ___ imparts color, texture, and overall appearance to the mold colony.
mycelium
28
Molds that possess melanin pigments in their cell walls are described as
dematiaceous
29
On the other hand, molds that do not produce pigments in their cell walls are described as
hyaline
30
hyaline means
transparent or transluscent
31
he mycelia can be differentiated as
submerged
aerial
fertile
32
are those that penetrate and anchor the thalli in the substrate and absorb the nutrients.
submerged mycelia
33
are those that grow above the substrate
aerial mycelia
34
are aerial mycelia that bear the reproductive structures such as conidia or sporangia
fertile mycelia
35
Fertile mycelia are aerial mycelia that bear the reproductive structures such as
conidia
sporangia
36
Molds also form various types of reproductive spores. Two kinds of asexual spores are seen in molds, the
sporangiospores
conidia
37
are spores that form within a sac called a sporangium.
sporangiospores
38
Sporangiospores are spores that form within a sac called a
sporangium
39
he sporangia are attached to stalks called
sporangiophores
40
are spores that form on specialized hyphae called conidiophores.
conidiophore
41
conidia are spores that form on specialized hyphae called
conidiophore
42
If the conidia are small, they are called
micronidia
43
Large multicellular conidia are known as
macronidia
44
There are four types of conidia
phialospore
blastoconidia
athrospore
chlamydospore
45
conidia are produced by vase-shaped cells called phialides
phialospore
46
conidia are produced from budding of preexisting conidia)
blastoconidia
47
onidia formed by separation from preexisting hyphal cells)
arthrospore
48
spores are large, thick walled, round, or irregular structures formed within or on the ends of a hypha
chlamydospore
49
___ reproduction in molds involves the union of compatible nuclei.
sexual
50
sexual spores result from a mating between two different organisms or hyphae which include the
oospore
zygospore
ascospore
basidiospore
51
produced when male gametes enter a large spherical cell called oogonium and fertilized the egg within
oospore
52
formed by union of two h protrusions from neighboring hyphae of two different strains
zygospore
53
produced enclosures, which may be oval sacs or elongated tubes called asci
ascospores
54
produced externally on club-shaped bodies called basidia
basidiospores
55
s a technique used to identify yeasts and other fungi by growing them on a plate and examining them under a microscope
dalmau plate method
56
dalmau plate method is also known as
corn meal agar (CMA) technique
57
a coverslip is placed on the inoculatd place to make a ___ condition
microaerophilic
58
are eukaryotic organisms belonging to
one big group
fungi
59
One-celled and some
types are
multicellular. Assume
complex organization
as filamentous
organisms
fungi
60
fungi Grows as colonies of
___ appearance
forming networks
called mycelia
leathery
61
Unicellular
* Non-filamentous
* Reproduction carried out by budding/fission
yeast
62
* Multicellular forming structures called hypha.
molds
63
is a fungal infection caused by an imbalance of healthy bacteria and yeast in your body.
candidiasis
64
s an antifungal metabolite produced by the fungus Penicillium brevicompactum. It was initially discovered for its antifungal properties, but later research revealed its potential as a cholesterol-lowering agen
compactin
65
compactin s an antifungal metabolite produced by the fungus ___ ___. It was initially discovered for its antifungal properties, but later research revealed its potential as a cholesterol-lowering agen
penicillum brevicompactum
66
compactin s an antifungal metabolite produced by the fungus Penicillium brevicompactum. It was initially discovered for its antifungal properties, but later research revealed its potential as a ___-lowering agen
cholesterol
67
Techniques and Tools in the Study and
Identification of yeasts and molds
Slide culture
* Dalmau plate
* Potato dextrose agar
* Sabouraud dextrose agar
* Czapek-Dox agar
* Molecular methods
68
are non-coding sections of DNA located between the conserved coding regions of ribosomal RNA (rRNA) gene
internal transcriber spacer
69
is widely used for identifying and classifying fungi because these regions exhibit significant variability, making them excellent markers for phylogenetic studie
fungal ITS sequencing
70
yeast culture
saccharomyces sp
71
stains used
5% malachite green
safranin
72
dalmau plate method
Make a single streak of a yeast culture at the ___ of a pre-poured PDA plate.
center
73
. With flame-sterilized forceps, put an autoclave-sterilized ___ ___ on top of the streak.
dalmau plate method
cover slip
74
Exhaust the air bubbles trapped underneath the cover slip by carefully ____ the
coverslip with flame-sterilized forceps.
dalmau plate method
pressing
75
dalmau plate method
s. Incubate the plate in an inverted posiAon at ___°C
for ___ h.
30oC for 48h
76
Remove the ___ of the plate and mount the plate directly on the microscope.
AlternaAvely, carefully remove the coverslip and place on a clean glass slide with a droplet
of water and observe under the microscope.
dalmau plate method
lid
77
Dalmau plate method
Observe for the presence of true or
pseudomycelia under what objectives
LPO or HPO
78
Streak the yeast for isolaAon separately on PDA plates. Incubate as indicated above
.
2. Observe colony morphology on PDA (not the Dalmau plate) every day for one __.
cultural characteristics
week
79
what cultural characteristics are observed
surface
edge
margin
color
texture
80
different surface of colony
smooth
concentric
contoured
wrinkled
81
view different surface of colony
+1
82
different edge/margin of colony
entire
lobate
filamentous
curled
undukate
83
view different margin of colony
+1
84
different consistency of colony
dry
butyrous
viscid
85
optical features of colony
transparent
opaque
transluscent
opalescent
86
elevation of colony
flat
raised
convex
umbonate
crateriform
pulvinate
87
. Prepare a wet mount by suspending a small amount of yeast from PDA plates in a drop
of ___ on a slide. Place a cover slip on top of the mount
asexual reproduction
water
88
Examine the preparaAon under __. Take note of the following features:
mode of asexual reproduction
HPOa
89
different shape of vegetative cell of yeast
spheroidal
subglobose
ellipsoidal
ovoid
cylindrical
elongate
apiculate
90
most visible structures in a cell yeast
granules
vacuoles
91
method of aseuxal reproduction of yeast
budding
92
The primary method of asexual reproduction in yeast is called
budding
93
1. Grow culture on PDA for __days (or unAl next meeAng) at 25°C.
sexual reproduction
3-5
94
. With a flame-sterilized loop, obtain a small amount of culture from the PDA. Spread it
thinly on the glass slide with a droplet of water. Air dry and heat-fixed smear by passing
the slide three Ames on the flame of an __ lamp.
alcohol lamp
95
Cover smear with absorbent paper/paper towel to prevent accumulaAon of arAfacts.
Flood smear with ___ ___ and stain for 30 min or steam the slide on a staining
pan for 7 min. Ensure that the stain does not dry up by checking from Ame to Ame.
malachite green
96
: If steaming of the slide will be performed, do it under a fume hood fume of malachite
green is ___.
carcinogenic
97
Remove the absorbent paper/paper towel with forceps and wash thoroughly with tap
water. Remove all excess water by allowing the slide to stand in a ____ posiAon for a
few seconds
vertical
98
. Counterstain with ___ for 30-60 sec. Wash the slide and blot dry. Examine under
OIO.
safranin
99
Ascospores (or basidiospores, if present) should appear __ while the vegetaAve
cells should be __ ___.
green
pink red
100
Note: Sexual reproductioon may not be readily observed in ___ cultures. Incubate for
more than one week to confirm ability to form ascospore or basidiospore.
young
101
. Remove the cover of the plate. Invert the boMom part of the plate containing the prepoured medium. With a flame-sterilized needle, do a ___ ___ ____ of the
mold culture on the center of the PDA plates. Incubate in inverted posiAon at 30-35
degrees Celsius for 1-7 days
sequential point inoculation
102
. Remove the cover of the plate. Invert the boMom part of the plate containing the prepoured medium. With a flame-sterilized needle, do a sequenAal point inoculaAon of the
mold culture on the center of the PDA plates. Incubate in inverted posiAon at 30-35
degrees Celsius for __ days
1-7 days
103
Rhizopus sp. and Mucor sp. grow well on PDA. Store the inoculated plates with
Rhizopus sp. and Mucor sp. in the refrigerator aHer the hour of incuba?on to avoid
___.
overgrowth
104
possible identity of mold
rhizopus sp.
mucor sp.
105
. Sterilize a Petri dish containing the following: filter or paper towel as boMom lining, a
bent glass rod/toothpick, coverslip and glass slide.
what method
slide culture method
106
2. Pour ___ water on the plate unAl the filter or paper towel is property
aterile
107
Prepare an agar block by pouring a thin layer of PDA (about ___mm thick) into a sterile
plate. Slice the solidified PDA with a flame-sterilized wire approximately 1-cm square
blocks. LiX the agar block and deposit on the center of the glass slide inside the plate
prepared in step 1
3-5mm thick
108
Inoculate all four upper edges of the PDA block by touching the __ culture using
sterile wire needle and deposiAng small amounts into the block.
mold
109
With flamed-sterilized forceps, place the autoclaved ___ slip on the inoculated PDA
block.
cover
110
Remove slide culture from the plate. Wipe dry the moisture at the boMom part of the
slide and examine the agar block under ___ to ___. O
LPO to HPO
111
character of hyphae
septate
non septate
aerial or submerged
112
Character of fruiAng body
color
position
arrangement
113
nature of spore bearing hyphae
enlarged tip
branched tip
branched
114
details of spore
color
shape
septations
115
presence of vegetative structures such as
stolons
rhizoids
116
re root-like structures in mold that anchor the mold to its food source
rhizoids
117
a horizontal hypha that helps the mold spread and reproduce asexuall
stolon
118
Prepare a wet mount of the slide culture. If a semi-permanent mount is desired,
carefully liX the cover slip of the slide culture and deposit on a slide 1 to 2 drops of
lactophenol
119
Adsorb excess mounAng fluid with clean filter or Assue paper and seal the
sides of the cover slip with nail polish or ___.
paraffin
120
width of yeast
1-5um width
121
shape of yeast
egg shaped, elongated, or spherical
122
what are locomotory organelles of yeast
n/a
123
yeast is identified by ___ or ___
bud or bud scars
124
After the bud detaches from the parent cell, it leaves a mark known as a
bud scar
125
morphology of yeast
cell wall
periplasm
plasma membrane
protoplasm
nucleus
peroxisome, golgi, ER
ribosome, mitochondria
vacuoles
secretory vesicles
126
mold is a ___ fungi
filamentous
127
two parts of thallus
mycelium
spores
128
resistant, resting dormant cells are called
spores
129
spores on germination puts out "___ ___"
germ tube
130
is a small, tube-like outgrowth that extends from a germinating spore.
germ tube
131
elongate to form hyphae
germ tubes
132
network of branched htphae
mycelium
133
morphology of molds
hyphae with outer tube like cell wall
134
cavity of hyphae is called
lumen
135
cavity of hyphae (lumen) is filled with
protoplasm
136
double layered membrane between cell wall and protoplasm
plasmalemma
137
mold cell wall is made up of
matrix + microfibrils
138
growth of fungal hyphae
growth at ___ end
distal end
139
growth of fungal hyphae
division by ____ formation
cross wall formation
140
growth of fungal hyphae
____ streaming
protoplasmic streaming
140
growth of fungal hyphae
cross wall grow ___
inwards
141
growth of fungal hyphae
incomplete septum with central ___
pores
142
growth of fungal hyphae
cell division followed by ___
karyogamy
143
This step involves the fusion of these distinct nuclei from the two parent mycelia
karyogamy
144
forms of fungal hyphae
coenocytic
monokaryotic
septate dikaryotic or multinucleated cell
145
non septate cell wall
coenocytic
146
septate uninuclated cell
monokaryotic
147
molecular method of determining fungi
using PCR
148
semisynthetic growth medium, has sodium nitrate, sucrose, salts
czapek dox agar (CDA)
149
to cultivate and identify fungi
low pH
high conc. of dextrose
SDA AGAR
150
is more commonly used for a broad range of fungi, especially yeasts and molds
SDA
151
is tailored for specific fungi like Aspergillus and Penicillium.
CDA
152
Contains dextrose (glucose), peptone, and agar.
pH: Typically around 5.6, which favors fungal growth and inhibits many bacteri
Sabouraud Dextrose Agar (SDA)
153
types of fungal mycelia
submerged
reproductive
154
reproductive fungal mycelia is ___
protrude from media
155
vegatative fungal mycelia is __ in the medi
asubmerged
156
hat method minimizes disturbance
slide culture method
157
also called as CMA method
dalmau plate method
158
CMA means
cornmeal agar
159
made from potato extract aand dextrose, provides nutrients and carbohydrates, low pH
potato dextrose agar
160
shape of yeast specimen
ovoid or ellipsoidal
161
lighter, clear areas within the cells
vacuoles
162
lighter, clear areas within the cells
granules
163
yeast surface, edge, color, and texture
creamy white
smooth
entire
mucoid or creamy
164
In the picture above, there are some cells that are stained green. A sexual spore of a yeast is called
ascospore
165
read the results in worksheet
+1
166
1. What is the purpose of the cover slip in Dalmau plate?
The purpose of using a coverslip in the Dalmau plate is to depict chlamydospores and other structures. Utilizing this reduces oxygen tension, aids in focusing under a microscope, and protects the microscope's objective from contamination. Placing a coverslip ensures proper viewing of the specimen allowing the observer to see the growth pattern, hyphae, and other cellular components under a microscope.
167
2. How is Schizosaccharomyces morphologically different from Saccharomyces?
Schizosaccharomyces and Saccharomyces differ in terms of cell shape, cell wall, and mode of reproduction. Schizosaccharomyces are usually rod-shaped and reproduce by fission (S.pombe), and the cell wall contains a unique component called pseudonigeran in addition to β-glucans. Whereas Saccharomyces is spherical or oval and reproduce by budding (S.cerevisiae) and their cell wall primarily consists of β-glucans and chitin.
168
1. Discuss the principle of using PDA plates in studying yeast cultures.
Potato Dextrose Agar (PDA) is a medium used for the cultivation and study of yeast cultures due to its ability to provide the needed nutrients for fungal growth. For its composition, potato infusion serves as its nutrient base, while dextrose is considered as its carbohydrate source to stimulate yeast metabolism and proliferation. Additionally, PDA is often adjusted to have 3.5 pH using tartaric acid and the addition of antibiotics like chloramphenicol is used to inhibit bacterial proliferation while allowing fungi to thrive. Thus, PDA is ideal to isolate and enumerate yeast due to its capacity to aid in fungi sporulation.
169
4. Why is malachite green used in ascospore staining?
Malachite green is used in ascospore staining since it has properties that make the ascospore readily take up its pigment. Unlike vegetative cells, sexual spores can take up malachite green by applying heat to the sample. Malachite green penetrates the tough outer layer of ascospores, which are resistant to staining under normal conditions. Thus, this dye provides a good contrast between the ascospores and vegetative cells for easier microscopic examination and visualization.
170
5. What is the significance of having asexual and sexual modes of reproduction?
5. What is the significance of having asexual and sexual modes of reproduction?
171
6. What other characteristics should be used to accurately identify yeasts?
Other than using the microscope to observe its morphology (cell shape, budding patterns, presence of hyphae, color, etc.), just like what we did in this worksheet, there are other ways of accurately identifying the characteristics of yeasts. Some include; the usage of sugar fermentation tests and assimilation reactions to determine their metabolic capabilities. Another one is to possibly use Germ tube tests, wherein it is useful for identifying specific species Candida. Another is to use modified media such as chromogenic media tools like CHROMagar Candida help differentiate species based on color reactions. Additionally, the use of molecular sequencing, particularly MALDI-TOF, provides precise identification through genetic analysis.
172
7. What is the reason for inverting the bottom part of the plate during point inoculation of a mold?
Inverting the bottom part of the plate during point inoculation of the mold prevents condensation droplets from the lid from dripping onto the agar surface. Should these droplets fall onto the inoculated area, they could disrupt the growth pattern and potentially contaminate the culture. Further, when incubated in the normal position, water from the media evaporates, causing media dryness and colony mix-up.
However, there are instances where the incubation of plates is done right-side up. In the laboratory activity, the plate used for slide culture set-up is incubated with the lid facing up. The upright position ensures proper gas exchange, avoiding invasive growths on the lid. Anaerobic strains are also incubated right-side up to allow space between the dish and the lid for gas exchange, removing oxygen. In this scenario, should the dish be incubated upside down, the condensation may act as an insulator, preventing gas exchange.
173
8. What will happen if you wet the agar block in the slide culture set-up?
The slide-culture set-up allows microscopic observation of fungal structures on a small agar block. Careful control of the moisture level promotes healthy growth and sporulation of the specimen. If the agar block becomes wet in the slide culture set-up, it will be overly saturated with water, disrupting growth due to alterations in the controlled environment. An environment too wet for optimal development may lead to poor sporulation and difficult specimen observation. Excess water swells the specimen's morphology, distorting it. Many specimens require specific conditions to produce spores; therefore, excessive moisture inhibits spore formulation. Furthermore, a very wet agar may encourage the growth of unwanted bacteria, further complicating the process and observation. ________________________________________
174
9. What are the advantages of using slide culture technique over wet mount technique for studying molds?
The considerations in using slide culture to wet mounts for studying molds opens preservation of the fragile fungal structures (e.g. conidia) by direct growth on the slide different to the distortive behavior of wet mount preparation. The direct growth minimizes artifacts during sample transfer. Slide culture has a clearer visualization of undisturbed fungal morphology; thus, it is more reliable in terms of studying molds.
175
10. What other morphological characteristics should be used in identifying molds?
The standard structures studied in molds are conidia, conidiophores, metulae, vesicle, sterigma, and its mycelia. However, inferring these characteristics, hyphal features, spore producing structures, spore morphology, colony appearance, and specialized structures should be used in identifying molds as it can create accurate interpretations in deducing molds.
