Notes:
1) The structure of fungi:
The body of fungus is called thallus. The main body of most fungi is made up of fine, branching, usually colourless threads called hyphae. Each fungus will have vast numbers of these hyphae, all intertwining to make up a tangled web called the mycelium.
The mycelium is generally too fine to be seen by the naked eye, except where the hyphae are very closely packed together. The picture on the left was taken through a microscope.
2) There are two types of hyphae: septate hyphae and coenocytic hyphae. Septate hyphae have divider between cells and there have opening pores between the cells which allow the flow of nutrient and cytoplasm between the cells. Coenocytic hyphae form one cell with many nuclei.
3)
Fungi undergoes asexual and sexual reproduction. There are three types of asexual reproduction: Bud formation, fragmentation and sporulation.
- Bud formation
- Mitosis process
- Development of a ring of chitin around the point of budding
- enzymatic activity extrude the cell wall and cell content are forced into the progeny cell.
- At the end of mitosis, a cell plate forms and the new bud detaches.
- Fragmentation
- any mycelium that is fragmentated can grow into a new colony.
- common sub-culturing method for fungi ( hyphal fragment technique)
- cork bore taken from a colonized donor plate. Cut mycelial tips do not generate but branches can form some distance from the damage point.
- Sporulation
- the production of spores on a phase called mitosporic, or anamorphic phase
- Arthrospores are formed through segemntation and condensation of hyphae.
- Chlamydospores are spores that surrounded by thick cell wall.
- Sporangiospores are the development of spores within a sac at hyphal tip.
- Conidiospores are spores that are not enclosed in sac produced at the tips or sides of hypha.
- Blastospores are spores produced from mother cell by budding.
4) For sexual reproduction, the different mating types need to fuse to form diploid first, but once fused the nuclei undergo mitosis. The event are followed by the formation of spores, which in most cases are resting spores that can withstand adverse conditions.
5) Slime molds once placed in kingdom Fungi but now placed in kingdom Protista. slime mold resemble fungi in appearance and life style but different in cellular organisms, reproduction and life cycle. Four different phyla of slime molds are:
- Myxomycota
These slime molds are designated as myxamoeba because their morphology are similar to amoeba. They are multinucleated, lack of cell wall, and phagocytosized dead material. The life cycle of myxocetes will start with the production of spores, then the release of myxamoebae. If free water is available, myxocetes will differentiate into swarm cells. Then sexual reproduction will occur where the swarm cells will normally act as gametes. Once compatible mating strains have come into contact with one another, syngamy will occur to form the zygote. The zygote then undergo numerous mitotic divisions to form the large, multinucleate plasmodium. This class is commonly referred to as the acellular slime molds because the plasmodium stage of the lif ecycle is not composed of many cells. During favorable conditions, the plasmodium will migrate and feed for a period of time before being converted to numerous sporangia.
- Acrasiomycota
Cellular slime molds closely resemble amoebas in structure. These molds live independently until food runs out. A starving amoeba secretes the hormone cyclic AMP into the environment. Other amoebas detect the cyclic AMP as a food source and aggregate from great distances to follow the concentration gradient to the dying amoeba. The amoebas then attach to one another and become what seems to be a functioning multicellular organism. The moving slug finds a suitable habitat before forming itself into a diploid fruiting body called a sorocarp, which releases encysted amoebas or diploid macrocysts. The released amoebas live independently until food resources are depleted, then the cycle is repeated.
- Oomycota
Oomycetes are water mold and oogamous where is produces large female gametes and small male gametes. Oomycetes were once recognised as fingi due to branched filaments and decaying dead matter. However, the cell wall of chitin is not composed of chitin, but with cellulose. Some water molds are parasitic because they live on fish or plant root which damage the plant root. As in humans as well as plants and other animals, sexual reproduction in the Oomycota involves specialized reproductive structures where meiosis can occur and gametes formed. These structures are called antheridia and oogonia in the Oomycota. The male and female fuse to form zygote.
6) Deuteromycota is known as fungi imperfecti because they are fungi which do not fit into the commonly established taxonomic classifications of fungi that are based on biological species concepts or morphological characteristics of sexual structures because their sexual form of reproduction has never been observed. Their cell wall is made up of chintin and glucan. They live in terrestrial, freshwater and marine. they are saprophytes and parasites of plants.
Activity: Presentation from group Fungi and group Algae.
My own explorace:
1) Zoonosis is the disease that directly transmitted from animal to human.
2) Potato Dextrose Agar contains dextrose as a carbohydrate source, and potato infusion to supply other necessary growth requirements. Potato infusion provides a nutrient base for luxuriant growth of most fungi.
3) The lactophenol cotton blue (LPCB) wet mount preparation is the most widely used method of staining and observing fungi and is simple to prepare.
4) Mycosis is a fungal infection of animal and human. Mycosis often misdiagnosed as TB because of their clinical and radiological characteristics are almost the same.
5) Endophytes are bacteria or fungi that live within a plant for at least part of its life without causing apparent disease.
6) Fungal allergens are generally proteins, and are often enzymes released from the fungal spore during germination, although some may also be proteins located on the surface of spores.
7) Most secondary metabolites are produced after fungi have completed its initial growth phase. Therefore secondary metabolites normally produced at the end of log phase. Some secondary metabolites produced by fungi are harmful but some are beneficial. The examples of secondary metabolites are penicillin, alfatoxin and gibberellin.
8) Normal fungi can just grow in petri dish while lower taxonomic microbes must grow in broth.
Reflection:
I don't really like fungi if compared to other microorganisms because I always confused with the life cycle of fungi. Sometimes I thought I understand the life cycle of fungi, but I can't explained to others because I know I am not really understand about it. The structure of fungi sometimes also make me confused. I can't imagine how thallus, hyphae and mycelium look like so I tried to search the image of thallus, hyphae and mycelium in the internet but I really wish to see the real thallus, hyphae and mycelium.
My own explorace:
1) Zoonosis is the disease that directly transmitted from animal to human.
2) Potato Dextrose Agar contains dextrose as a carbohydrate source, and potato infusion to supply other necessary growth requirements. Potato infusion provides a nutrient base for luxuriant growth of most fungi.
3) The lactophenol cotton blue (LPCB) wet mount preparation is the most widely used method of staining and observing fungi and is simple to prepare.
4) Mycosis is a fungal infection of animal and human. Mycosis often misdiagnosed as TB because of their clinical and radiological characteristics are almost the same.
5) Endophytes are bacteria or fungi that live within a plant for at least part of its life without causing apparent disease.
6) Fungal allergens are generally proteins, and are often enzymes released from the fungal spore during germination, although some may also be proteins located on the surface of spores.
7) Most secondary metabolites are produced after fungi have completed its initial growth phase. Therefore secondary metabolites normally produced at the end of log phase. Some secondary metabolites produced by fungi are harmful but some are beneficial. The examples of secondary metabolites are penicillin, alfatoxin and gibberellin.
8) Normal fungi can just grow in petri dish while lower taxonomic microbes must grow in broth.
Reflection:
I don't really like fungi if compared to other microorganisms because I always confused with the life cycle of fungi. Sometimes I thought I understand the life cycle of fungi, but I can't explained to others because I know I am not really understand about it. The structure of fungi sometimes also make me confused. I can't imagine how thallus, hyphae and mycelium look like so I tried to search the image of thallus, hyphae and mycelium in the internet but I really wish to see the real thallus, hyphae and mycelium.
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