TEST 1 MIC 206 6^th August 2008 (Revision Question)

By:                   Khairul Anwar Bin Abu Mansor

                        Faculty Of Applied Science; Universiti Teknologi MARA Malaysia

1.       Define these terms :-

a.       Teleomorph

The sexual stage in the life cycle of a fungus that has both sexual and asexual states

b.      Mycelium

Mass of hyphae constituting the body (thallus) of a fungus.

c.       Negative staining

d.      Condiophore

A simple or branched hypha arising from a somatic hypha and bearing at its tip or side one or more conidiogenous cells; previously used interchangeably with conidiogenous cell.

e.      Saprophytic fungi

f.        Woronin bodies

An electron-dense, spherical body found in the hyphae of Ascomycota and many Deutromycetes; Woronin bodies are usually concentrated near septa.

2.       List one (1) difference and one (1) smillarity between Saccharomyces cerevisiae and Penicillium italicum.

3.       List two (2) differences between the two divisions Eumycota ( True Fungi ) and Myxomycota ( Slime Moulds )

4.       List two (2) basic features of Chytridiomycetes and name one (1) Chytridiomycete

5.       State one (1) special feature of a zygomycete

It’s produce zygospore

6.       Describe with the aid of diagram the asexual reproduction of the Zygomycete, Rhizopus stolonifera (Hint! Besides the descriptions, relevant diagram with labels will also be given marks)

7.       Write short notes on the condition called histoplasmosis

8.       Name one (1) Deutromycete that is a plant pathogen and one (1) that is an animal pathogen (Note which is which)

9.       Describe the economic importance of Aspergillus

Aspergillus is able to utilize enormous varieties of substances for food as they produce a large number of enzymes.

10.   State one (1) difference between moulds and yeasts

MIC 206 – Fungi and Other Organisms Questions

By :               Khairul Anwar Bin Abu Mansor

                        Universiti Teknologi MARA Malaysia

1.       Different between Parasitism and mutualism

2.       Defination of Facultative Symbionts, Obligate Symbionts, Biotrophic Association, Necrotrophic Association

3.       How do fungi infect plant:

Through : Aerial surface, Root surface, wounds, internal tissues (endodermis, phloem, xylem)

4.       Fungi (relating to features) that help in the infection process

5.       Necrotrophic

6.       Biotrophic Attack

7.       How plants control fungal attack?

-          Biological control

-          Breeding disease resistance plant

-          Integrated control

8.       Fungi and animals
-  Fungi that attack animals

-    Fungi that line as mutual symbionts

-    Fungi as food to animals

9.       Mycoparasitism

* The Aswer will be update later

Sections.

1.       Differentiate between parasitism and mutualism

2.       Defination of Facultative symbionts, Obligate symbionts, Biotrophic  Asssciation, Necrotrophic Association

3.       How do fungi infect plants. Through : Aerial surfaces, root surfaces, wounds, internal tisues (endodermis, phloem, xylem)

4.       Fungi (relating to features) that help in the infection process.

-          Airbone pathogenic fungi

-          Root infected by fungi

5.       Necrotrophic attack

6.       Biotrophic attack

-          VAM

-          Orchidaeceous Mycorrhiza

-          Ericaceous Mycorrhiza

-          Ectomycorrhiza

-          Endophytes

7.       How plant control fungal attack

-          Biological control

-          Breeding disease resistant plants

-          Integrated control

8.       Fungi and Animal

-          Fungi that attack animals.

-          Fungi that line as mutual symbionts

-          Fungi as food to animals.

9.       Mycoparasitism

UNIVERISITI TEKNOLOGI MARA MALAYSIA

A FUNGI THAT ACT AS DECOMPOSERS

BY

Khairul Anwar Bin Abu Mansor

Student no 2006 60 6761

Diploma Microbiology, Faculty of Applied Science

Universiti Teknologi MARA Malaysia, Shah Alam

INTRODUCTION

The decomposition of organic matter is brought about by wide range of fungi and other organisms such as bacteria, nematodes, mites, springtails, etc acting in consort. The types of organism that are active in these communities can vary, but the overall course of decomposition is similar in many situations because it involves an overlapping sequence of activities of fungi with different patterns of behavior and different abilitiy to degrade particular types of substrate.

The table below shows the main behavioral grouping of decomposer fungi.

CHYTRIDS : PHYLUM CHYTRODIOMYCOTA

This phylum is the powerdul decomposers. The studied, shows that most of the thousand or so species of chytrids are saprophytes. Chytrids are microscopic and widespread, occurring in soil, bogs, fresh and marine water, and even inside plants and animals.

They are single-celled or form short chains of cells and some produce a limited hyphal mycelium buried in the substrate. The hyphae lack sepra, and are termed ceonocytic. Chytrids are considered to be the earliest line of evolution because they have retained some primitive features, such as motile zoospores similar to protists.

The special feature of chytrids is they produce the amino acid lysine by the aminoadipic acid pathway, have flat mitochondrial cristae (in aerobic species) and contain chitin microfibrils in their cell walls.

Chytridiomycota have unicellular or mycelial thalli. Cell walls are made of chitin, although one group has walls made of cellulose. Cell growth can be unicellular, or it can occur in the multicellular mycelium of aseptate hyphae. The thallus is typcially unicellular; it may also have limited hyphal growth. It is not considered mycelial. Hyphal cells are coenocytic, although this is not the case where there are reproductive structures. The ultrastructure of the zoospore is a definitve characteristic of Chytridiomycota. In the structure, ribosomes are aggregated around a nucule that is not enclosed in a nuclear cap. A nuclear cap is an extension of the nuclear membrane. Chytridiomycota have one or two flagella. .

Chytrid zoospores have a single, smooth, posterior flagellum. A second basal body, without a flagellum, is located near the functional basal body. Although hyphae are coenocytic, a septum forms to delineate the sporangium. In species where sexual reproduction has been described, “+” and “-“ strains of haploid, uniflagellate gametes are released and fuse to form the diploid zygote. The zygote undergoes meiosis as it germinates to release haploid zoospores, often after a long dormancy.

The example of the species of chytrodiomycota is Allomyces macrogynus

THE LIFE CYCLE OF THE CHYTRIDIOMYCETE

Figure 1 : The life cycle of Chytridiomycete

Asexually, Chytridiomycota reproduce through the use of zoospores. In asexual reproduction, zoospores will swim until a desireable substrate is located. The zoospore attaches itself, feeds off its host; the cytoplasm grows, meiotic divisions occur, and a cell wall forms around the original zoospore. Protoplasm increases as the cell continues to develop.

Finally, cleavage of the protoplasm occurs, which produces individual zoospores that are released through a pore. Sexual reproduction is haploid dominant. It also depends on the isomorphic alternation of generations. The haploid thallus, called the gametothallus, produces female and male gametes. These occur in pairs and are terminal and subterminal. Male gametes are orange-colored, while female gametes are colorless. In addition, female gametes are much larger than male gametes. Males are attracted to females when they produce the hormone sirenin, and females are attracted to males when they produce the hormone parisin.

The diploid thallus is called the sporothallus. The sporothallus produces two types of zoosporgia: zoosporgangium (meitosporangium) and resistant sporangium (meiosporangium). Zoosporangia produce diploid zoospores, which can function as a means of asexual reproduction. Sexual reproduction may be isogamous, anisogamous, or oogamous. One species, Allomyces macrogynus, has a sporic life cycle, something that occurs in plants but is rare to fungi. A. macrogynus is an example of an anisogamous species.

CONCLUSION

Most of the species of the fungi can be act as a decomposers. Its will change from the complex structure to the simplest structure. For example from the carbohydrate to carbon.

REFERENCES

1.       Jim Deacon (2006)  Fungal Biology, Blackwell Publishing  P:413-437.

2.       Campbell and Reece (2002) Biology 6^th Edition, Pearson Education P: 616-630

3.       I Knox, R. Bruce. (2005) Biology 3^rd Edition, MacGraw Hill Australia P: 893-915 

Heterotroph – is an organism that requires organic substrates to get its carbon for growth and development. Its kown as a consumer in the chain.

Autotorphs – use inorganic carbon dioxide or bicarbonate as sole carbon source.

All animals are heterotrophic, as well as fungi and many bacteria.

Heterotophs are unable to synthesize organiz carbon-based compounds independenly from the inorganic environment’s sources and therefore must obtain their nutrition from another heterotrophy or an autotroph.

Heterotroph – obtains its carbon form organic compounds

Autotroph – obtains nitrogen from organic compounds, but not energy.

There 2 possible subtypes of the heterotrophs

-          Photoheterotrophs – obtains energy from light and must obtain carbin in an organic form.

-          Chemoheterotroph – obtains energy from the consumption of organic molecules and and organic form of carbon