Oomycota
Oomycota is one of protist like fungi that can live in water or damp places and have Oospora as a producer of Spore. Spores produced by thick-walled zygote that serves as protector. In certain circumstances spores will grow into new hyphae. its characteristic features :
A. Characteristics Oomycota
1. Hyphae are not insulated
2. Reproduce asexually by forming zoospores result of fusion of male and female gametes. Zoospores is equipped with a tool in the form of two pieces swim
flagellum.
flagellum.
3. Oomycota substitution of samples and saprolegnia phytium
4. Get food from the rest of the remaining plants
5. Living in dead plant tissue
6. 580 Species that act as decomposer in aquatic
7. Life freely
8. Generative in fertilization that will form a growing zygot becoming oospora
9. The walls of cellulose
B. Structure and Body Shape
Although based on morphology and their life-style, they traditionally classified in fungi shape, a modern classification, it is classified in eukaryotic group.
This relationship is support by their number of different observation and oomycota characteristic, and also fungi. For instance, wall cell oomycota is formed by cellulose and not cittin. And in vegetative model, they have diploid nuclei, where fungi have haploid nuclei. Most oomycetes Most oomycetes produce self-motile zoospores with two flagella. One flagellum has a "whiplash" morphology, and the other a branched "tinsel" morphology. Spores of the few fungal groups which retain flagella (such as the Chytridiomycetes) have only one whiplash flagellum. Oomycota and fungi have different metabolic pathways for synthesizing lysine and have a number of enzymes which differ. The ultrastructure is also different, with oomycota having tubular mitochondrial cristae and fungi having flattened cristae. In spite of this, many species of oomycetes are still described or listed as types of fungi and may sometimes be referred to as pseudofungi, or lower fungi.
C. How to Move
Oomycete cells differ from fungi as they have walls of cellulose and hydroxyproline amino acids. They are heterotophic, both saphropytic or parasites. Oomycetes can reproduce asexually, by forming a structure called a sporangium or zoosporangium. Within these sporangia, zoospores are produced, the first primary zoospores and then secondary zoospores, which laterally flagellated. their flagella allow zoospores to move quickly through water.
D. How To Get Food
Oomycetes is saprophyte, so it get food from the remaining plants.
E. How To Breathe
F. How To Reproduce
Most of Oomycota reproduce two kind of different spore.
- Asexual Reproduction
The main spore that is produced is called by Zoospora. How to produce zoospora it is like this.
1. It will reproduce sporangium at the tip of their hyphae (filament/thread)
2. In the sporangium, will be filled by flagellated spora or zoospora.
3. When zoospora is mature, zoospora will be released from sporangium
4. When zoospora fall in the optimal environment, zoospora will grow and become new mycelium.
It is move with Chemotaxist in water surface. Some of Oomycetes reproduce asexual aerial spore that distribute by wind.
Asexual and Sexual Reproduction
2 Sexual Reproduction
They also reproduce sexual spore that is called by Oospora. It is translucent, have double wall round shape that is used to survive in environment. The process of sexual reproduction:
1. Compatible oogonia and antheridia develop on the same diploid mycelium. Meiosis apparently occurs within these gametangia.
2. The oogonia are enlarged cells in which a number of spherical eggs (oospheres) are produced. The antheridia develop from the tips of other filaments of the same individual and produce numerous male nuclei.
3. In mating, antheridia grow toward the oogonia and develop tubular processes called "fertilization tubes", which penetrate the oogonia. Male nuclei travel down the fertilization tubes to the female nuclei and fuse with them.
4. Following each nuclear fusion, a thick-walled zygote, called the oospore, is produced. On germination, the oospore develops into hyphae, which then produces a sporangium, beginning the cycle anew.
G. Habitate
Some water molds are parasites on other organisms; they may grow on the scales or eggs of fish, or on amphibians. The water mold Saprolegnia causes lesions on fish which cause problems when the water is rather stagnant, as in aquaria or fish farms, or at high population densities, such as when salmon swim upstream to spawn. Other species of Saprolegnia are parasitic on aquatic invertebrates such as rotifers, nematodes, and arthropods, and on diatoms
H. Example Species
1. Phytophthora, a group from paraphyletic genus that cause disease like late blight potato, sudden oak death and american chestnut.
2. Paraphyletic Phytium, it is more familiar from phytophthora and its individual species have many number, usually causing less damage. It parasitize other oomycta and fungi and one of phythium species, is also known to infect mammals.
3. Downy mildews, which easily identifiable by the appearance of white, brownish or olive on the lower leaf surface
4. The fourth group is white blister rusts. They are obligate biotrophs, which means that they are unable to survive without the presence of living host.
