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EXAMINATION & EXERCISES #3

 

FOR THE ASCOMYCOTA

(Contact)

 

[For answers please also refer to:  Alexopoulos, C. J., C. W. Mims and M. Blackwell.

1996. Introductory Mycology. John Wiley and Sons, New York.]

 

_ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _

 

Fill in all blanks; underscore all correct parenthesized sections:


1. The special cell division process by which asc8spores are delimited is called. This process was first described by

          (Micheli)  (de Bary)  (Strasburger)  (Harper)  (Raper)  (Thaxter) about (1850)  (1875)  (1900)  (1925). The

          unused cytoplasm left in an ascus after spore delimitation is called _________.

2.  Eremothecium ashbyii is an important fungus {because it is an important plant pathogen) (because it is an

          important vitamin source) (because of its scavenger activity in soil) (because it produces an important

          antibiotic.)

3. Three species of Taphrina are: T. ________, parasitic on __________; T. ____________, parasitic on

          ____________; T. __________________, parasitic on _________________.

4.  (All yeasts)  (Not all yeasts) are in the Ascomycota.

5.  Endomyces reproduces vegetatively by (sporangiospores)  (arthrospores)  (blastospores)  (ascospores.)

6. Vegetative cells of Taphrina are typically (uninucleate)  (binucleate)  (multinucleate). Chlamydospores--ie. Ascus

          initials-- in T. deformans are formed (subcuticularly)  (just under the epidermis)  (scattered among the host cells

          near the surface of the attacked host organ).

7. All fungi assigned to the Hemiascomycetes (produce many-spores asci)  (lack ascoearps) (are diploid or dicaryotic

          in their vegetative phase).  Representative genera of the Hemiascomycetes __________, __________ and

          __________.

8.  Dipodascus belongs in the order ____________.  Asci of Dipodascus have  (four)  (eight)  (many)  ascospores.

9.  Arachniotus is a member of the family, in the order __________________..

10.  An Oidium p'f imperfect stage is characteristic of (Elsinoe)  (Uncinula)  (Thielavia)  (Myriangium) 

          (Phyllactinia)  (Arachniotus)  (Sphaerotheca).

11.  Members of the genus incite plant diseases known as "spot anthracnoses."  These diseases are most prevalent in

          (the tropics)  (the temperate zones).

12.  In culture, on agar, species of Taphrina may closely resemble (Arachniotus)  (Saccharomyces)  (Endomyces)

           (Schizosaccharomyces)  (Ashbya) -- both macroscopically and microscopically.

13.  In comparing Arachniotus trisporus and Aspergillus amstelodami, it is found that: ~(both produce catenu~e conidia) (the conidia of both are colored) (the conidia of neither are colored)  (thet~asci are very different) ~(in both, the asci have a scattered arrangement)  (in both, the ascocarp has a firm and well-defined peridium) (both produce chlamydospores) (both produce racquet mycelium) (their natural habitats are similar.)

 

14.  "Aspergillosis" in birds usually involves infection by (Aspergillus niger)  (Aspergillus flavus)  {Aspergillus

          fumigatus).

15.  The following species of Penicillium incite important fruit rots: P. _____________, P _______________, and

          P. ________________

16.  Asci arise from ascogenous hyphae in (Erysiphe) (Arachniotus)  (Endomycopsis)  (Dipodascus)  (Eurotium).

17.  "Proasci" are encountered in the genus _______________.

18.  In nature, yeasts may be found (on the surface of ripe fruits)  (in the soil)  (on leaf surfaces)  (in the atmosphere).

19.  A yeast  (might)  (would not)  be expected to grow on a medium that was too acid to allow development of most

          bacteria but on which a wide variety of filamentous fungi could thrive.

20.  Saccharomyces cerevisiae  (can)  (cannot) utilize starch as a carbon source.

21.  In "haplobiontic" yeasts, cell fusion occurs immediately preceding ascus formation. An example of a haplobiontic

           yeast would be (Schizosaccharomyces octosporus)  (Saccharomyces cerevisiae).

22.  The yeast ordinarily used in baking  (is)  (is not)  a "sporogenous" yeast. The metabolic produce of the yeast that

          is concerned in the leavening of dough is ___________________.

23.  To induce rapid multiplication of cells of Saccharomyces in a suitable medium, the culture should be (well aerated) 

           (kept under conditions of low aeration).

24.  In the presence of an abundance of free oxygen Saccharomyces cerevisiae tends to produce _______________

           and ________________as end-products of its respiration. When the oxygen supply is low, alcohol and 

          ____________are produced. The alcohol is  (ethyl alcohol) (methyl alcohol) (butyl alcohol).

25.  Many species of Taphrina produce "secondary" ascospores in their asci, with the result that there are large

          numbers of spores in the spore sacs. This  (is)  (Is not) the way Taphrina defommans behaves.

26.  In the space provided, indicate the order to which you would assign each of the following genera:


Elsinoe            ______________
Ascoidea          ______________
Meliola            ______________
Thielavia        ______________
Protomyces     ______________

 

 

27.  Classify the following as indicated:

 

Class:  _____________________________

Subclass:  __________________________

Order:  _____________________________

Genus:            Microsphaera

Class:  _____________________________

Subclass:  __________________________

Order:  _____________________________

Genus:            Hanseniospora

 

 

Class:  _____________________________

Subclass:  __________________________

Order:  _____________________________

Genus:            Cunninghamella

Class:  _____________________________

Subclass:  __________________________

Order:  _____________________________

Genus:            Aphanomyces

 

 

 

 

28.  The Ascomycota genus Taphrina is assigned to the "Hemiascomycetes"  (because it forms no conidia)  (because

          some species produce multi-spored asci)  (because no ascocarps are produced)  (because all fungi that produce

          budding yeast-like cells are assigned to this sub-class).

29.  The value of a given unit on a stage micrometer scale is absolute-- always fixed. On the other hand, a given unit on

          an ocular micro- meter scale varies in value with the lens combination employed. Does the value increase or

          decrease when you change from a low power objective to an objective of higher magnification?

 

20.  For each of the items in the left column select from the column at the right one fungus or fungal group that fits that

          item, and enter the number of the selected organism or group in the appropriate blank:

 

ญญ_______ Peach leaf curl

_______ Sooty Mold

_______ Oidium imperfect stage

_______ Cleistothecium with one ascus

_______ Inoperculate discomycete

_______ Blastospores

_______ Ascostroma resembles a perithecium

_______ Arthrospores

_______ Apple rot

_______ Parasite on mushrooms

_______ Lung infections in birds

_______ Sphaceloma imperfect stage

_______ "Damping off" of seedlings

_______ Ergot

_______ Fish disease

_______ Holocarpism

_______ Parasite on insects

_______ Skin infection in humans

_______ "Blue stain" of wood

_______ Chestnut blight

_______ Production of riboflavia

_______ Racquet mycelium

_______ Beginning of mycogenetics

_______ Rhizomycelium

_______ Phototropic sporangiophore

_______ Columella

_______ Merosporangium

_______ Wheat scab

_______ Diplanetism

_______ Downy mildew

_______ Subterranean ascocarp

_______ Multispored asci

_______ Black knot of plum

_______ Metula

_______ Aureomycin

_______ Oogonium with one oospore

_______ "Green stain" of wood

_______ Periplasm

_______ European Elm Blight

_______ Hysterothecia on wood

 

 1.  Dibotryon

 2.  Endomycopsis

 3.  Streptomyces

 4.  Chlorosplenium

 5.  Hysterographium

 6.  Ophiostoma

 7.  Phycomyces

 8.  Urophlyctis

 9.  Neurospora

10.  Ashbya

11.  Endothia

12.  Dermatophytes

13.  Podosphaera

14.  Meliola

15.  Cordyceps

16.  Elaphomyces

17.  Syncephalis

18.  Gibberella

19.  Basidiophora

20.  Olpidium

21.  Claviceps

22.  Daldinia

23.  Saprolegnia

24.  Elsinoe

25.  Basidiophora

26.  Pythium

27.  Aspergillus

28.  Pyrenophora

29.  Allomyces

30.  Neocosmospora

31.  Hypomyces

32.  Endomyces

33.  Thielavia

34.  Penicillium

35.  Taphrina

36.  Chaetomium