1.Video Lesson

2.Objective

At the end of this lesson you will be able to:-

• Define archaea and fungi
• Categories archaea and fungi
• Describe the common characteristic of archaea and fungi
• Explain about useful and harmful aspects of archaea and fungi

Brainstorming questions

• Adaptations to Extreme Environments: How do unique features of Archaea, like branched hydrocarbon chains in their membranes, help them survive in extreme conditions? What specific adaptations in extreme thermophiles and halophiles should we explore further?
• Ecological Roles and Interactions: How do Archaea and fungi contribute to nutrient cycling in ecosystems? What impact do their interactions with plants and animals have on ecosystem health and stability?
• Biotechnological Applications: What innovative applications could emerge from studying the enzymes of Archaea and fungi? How can these enzymes be utilized in food production, environmental cleanup, or pharmaceuticals?

key words

• Archaea: A domain of unicellular, microscopic organisms that live as producers or decomposers, distinct from bacteria and eukaryotes.
• Prokaryotic: Lacking a membrane-bound nucleus and membrane-bound organelles.
• Methanogens: A group of archaea that generate methane, found in anaerobic environments like waterlogged soil and animal digestive tracts.
• Extreme Halophiles: Archaea that grow in highly saline environments such as salt lakes and evaporation ponds.
• Extreme Thermophiles: Archaea that thrive in extremely high temperatures, often exceeding 80°C, found near volcanic vents and hot springs.
• Crenarchaeota and Euryarchaeota: Two major phyla of archaea identified based on sequences of 16S ribosomal RNA genes.
• Peptidoglycan: A polymer that makes up the cell walls of most bacteria, but true peptidoglycan is lacking in archaea.
• Fungi: Eukaryotic, spore-bearing organisms with absorptive nutrition, lacking chlorophyll, and reproducing sexually and asexually.
• Mycology: The scientific study of fungi.
• Hyphae: Microscopic filaments that make up the body (mycelium) of a fungus.
• Chemoheterotrophic: Organisms that derive their energy from chemical reactions and carbon from organic compounds.
• Mycorrhizae: Symbiotic associations between fungi and plant roots.
• Lichens: Symbiotic associations between fungi and photosynthetic organisms like algae or cyanobacteria.
• Sporangiospores and Conidia: Types of asexual spores produced by fungi.
• Mycotoxins: Toxic compounds produced by fungi, which can cause diseases in humans and animals.
• General Concepts
• Binary Fission: A method of asexual reproduction in which a cell divides into two genetically identical cells.
• Chemolithoautotrophs: Organisms that obtain energy from inorganic compounds and carbon from carbon dioxide.
• Bioremediation: The use of organisms to remove or neutralize contaminants from a polluted area.
• Polymerase Chain Reaction (PCR): A technique used to amplify DNA sequences, utilizing the enzyme from the thermophilic archaea Thermus aquaticus.
• Saprophytic: Organisms that obtain nutrients by decomposing dead organic matter.
• Parasitic: Organisms that live on or in a host organism, deriving nutrients at the host’s expense.
• Symbiotic: Interactions between two different organisms living in close physical association, typically to the advantage of both.
• Solutes and Water Activity: The concentration of solutes in the environment affects microbial growth, as does the availability of water.
• pH: The acidity or alkalinity of the environment can influence microbial growth.
• Temperature: Microorganisms have specific temperature ranges for optimal growth.
• Oxygen Level: The availability of oxygen affects the growth of aerobic and anaerobic organisms.
• Pressure: Certain microbes can grow under high-pressure conditions.
• Radiation: Some microorganisms can withstand or are adapted to high levels of radiation.

Archaea

Similar to bacteria, specie in the Domain Archaea known as archaea’s, are unicellular, microscopic organisms that live as producers or decomposers.

Characteristics of Archaea

• They are prokaryotic.
• They single celled organisms.
• They lack membrane bound nucleus and membrane bounded organelles.
• Archaea lack true peptidoglycan in their cell walls.
• Their cell membrane lipids have branchedhydrocarbon chains
• Many are found in extreme environments.

Generally, there are three groups of archaea recognized. These are:-

• Methanogen
• Extreme halophiles
• Extreme thermophilic

This classification based on physiological characteristics of the organisms and therefore cannot be considered phylogenetic, or evolutionary

Methanogen

• they generate methane
• Strictly anaerobic organisms being isolated from anaerobic environments as waterlogged soil, lake sediments, marshes,marine sediments and gastrointestinal of animal tract.

Extreme halophiles

• Grow in highly saline environments such as the Great Salt Lake, the Dead Sea, salt evaporation ponds, and the surfaces of salt-preserved foods.
• Generally obligate aerobes

Extreme thermophilic

• Also known as hyperthermophiles are found  found in high temperature (excess of 80°C) near volcanic vents and fissures that release sulfurous gases and hot vapors.
• May be obligate aerobes, facultative aerobes, or obligate anaerobes.
• It is extreme Acidophiles: (two genera, Thermoplasma and Picrophilus,) are growing in extremely acidic, hot environments.

Beneficial aspects of Archaea

These Archaea become the source of enzymes that

• Are usually added to detergents in order to help it maintain its activity even at higher temperature and ph.
• Proteases and lipases derived from alkaliphilic bacteria are being used as detergent additives to increase their stain removal ability
• Some Archaea also bear the potential for bioremediation or help in cleaning contaminated sites.
• The thermophilic Archaea, Thermus aquaticus, is an essential part of the development of molecular biology as a science. Archean has become the source of the enzyme harnessed as the basis for the amplification of the DNA in a technique called Polymerase Chain Reaction (PCR).

Physical factors that affecting microbial growths

The growth of microorganism determined by their growth environment. The major physical factors which affect microbial growth are:-

• Solutes and water activity
• PH
• Temperature
• Oxygen level
• Pressure
• Radiation

Fungi

Microbiologists use the term fungus [pl., fungi; Latin fungus, mushroom] to describe eukaryotic organisms that are spore-bearing, have absorptive nutrition, lack chlorophyll and          reproduce sexually and asexually.

Scientists who study fungi are mycologists    [Greek mykes, mushroom, and logos, study], and the scientific discipline devoted to fungi is called mycology. The study of fungal toxins and their effects is called mycotoxicology, and the diseases caused by fungi in animals are known as mycoses (s., mycosis).

General Characteristics of True Fungi

• All are eukaryotic
• Most are filamentous Composed of    individual microscopic filaments called hyphae, which exhibit apical growth and which branch to form a network of hyphae called a mycelium. Some have septate hyphae, and the  other  have  non sepatate  (coenocytic hyphae)
• They lack chlorophyll pigments and are incapable of photosynthesis.
• All are chemoheterotrophic (chemo­ organotrophic). They utilize pre-existing organic sources of carbon in their environment and the energy from chemical reactions to synthesize the organic compounds they require for growth and energy.
• Protoplasm of  a hyphae or cell is surrounded by a rigid wall composed primarily of chitin and glucagons, although the walls of some species contain cellulose.

Ecology of Fungi

Fungi have adapted to nearly every environment on Earth, but they are especially common in cool, dark, and moist areas rich in decaying matter. As saprobes, fungi play a crucial role in breaking down organic material. Many fungi form beneficial mutualistic relationships with other organisms. For example, fungi often create intricate mycorrhizal partnerships with plant roots, and some ants cultivate fungi for food. Additionally, lichens represent a symbiotic relationship between a fungus and a photosynthetic partner, typically an alga or cyanobacterium. In this relationship, the photosynthetic organism provides energy and carbohydrates from light, while the fungus offers minerals and protection.

• Zygomycota. Sporangial    fungi,   E.g. rhizopus and mucor
• Ascomycota. Ascospore producing fungi. e.g. Saccharomyces cerviciae
• Basidomycota. Basidia producing fungi. E.g. rusts & smuts

Classification of Fungi

Currently there are five major groups of fungi, although recent genomic evidence indicates that the      chytrids and zygomycetes are paraphyletic,

Chytridomycota.       Zoospore producing fungi. E.g. allomyces & water molds

Glomeromycota. E.g. mycorrhizal fungi. Called fruiting bodies, which represent the parts of sporulation 

Reproduction in fungi

Fungus can be reproduce sexually and asexually (spore)

Asexually reproduction of fungi

Asexual reproduction in fungi involves the development of specialized hyphae that produce structures at their tips. Through mitotic divisions, these structures generate thousands of genetically identical spores in a process known as sporulation. Spores form within sacs or vessels called sporangia (singular: sporangium; “angio” meaning “vessel”), and these spores are referred to as sporangiospores. Some fungi produce spores on supporting structures known as conidiophores; these exposed, dust-like spores are called conidia. Fungal spores are lightweight and can be dispersed in large quantities by the wind. Additionally, some fungi produce spores through the fragmentation of hyphae, resulting in arthrospores (where “arthro” means “joint”), which can contribute to conditions like athlete’s foot.

Sexual reproduction in fungi

Economic importance of fungi

Fungi are among the economic important microrganisms. They have both beneficial and hammful aspects.

Beneficial aspect of fungi

• Fungi exist either as saprobes or parasites. it break down complex organic substrates that essential for recycling of nutrient (element).
• Edible (source of food) e.g. mushrooms (Basidiomycetes) .
• Yeasts are essential to many industrial processes involving fermentation. eg. In  making of bread, wine, and beer.
• Fungi also play a major role in the preparation of some cheeses, soy sauce, and sufu, bulla enjera etc and commercial production of organic acid citric, garlic drug(ergometrine,cortisone).
• Molds (such as Aspergillus species) are used in the production of citric, oxalic, gluconic and itaconic acid.
• A mold (Fusarium) can produce within 48 hours, 12- 15 grams of fat from a litre of 50% glucose solution.
• Fungi play a major role in the manufacture of many antibiotics (penicillin, griseofulvin) and the immunosuppressive drug cyclosporin.
• Fungi are important sources of antibiotics such as penicillin, amphotericin  adriamycin and bleomycin, etc. 8. Used for studying complex eukaryotic events, such as cancer and aging within a simple cell.

Harmful aspects of fungi

Diseas cuased

 major plant disease caused by fungus. Over 5,000 species attack economically valuable crops, garden plants, and many wild plants Fungi also cause many diseases of animals and humans.

2. Molds can cause deterioration of fabrics, leather, electrical  insulation  and  others

3. Spoil the agricultural produce, if improperly stored. These also destroy vegetables, fruits and cereals.

4. Mycotoxicoses (ingestion of toxins of fungal origin) and mycetismus (mushroom poisonmg through ingestion of fungal elements). These causes:-

• Aflatoxis:
• Ergotism
• Mushiroom poisoning(mycetism)

 Aflatoxis: Two closely related fungi, Aspergillus jlavus and A. parasiticus, produce mycotoxins called aflatoxins. The molds are found primarily in warm, humid climate  and contaminate agricultural products such as peanuts, grains, cereals, sweet potatoes, com, rice, and animal feed. Aflatoxins are deposited in

these foods and ingested by humans cause carcinogen.

Ergotism is caused by Claviceps purpurea  fungi produce powerful toxin. Claviceps purpurea grow as hyphae on kernels of rye, wheat and barely and hyphae penetrate the plant then consume the grain of the plant and the tissue of the grain became harden into purple body called sclerotium. a group of peptide derivatives called alkaloids produced in the grain i.e called Ergot. humans feed this grain became ergotism.

Mushroom poisoning, or mycetism, can occur from mushrooms that produce mycotoxins that affect the human body.

5.supperficial fungal infection:- Superficial mycoses are fungal infections of the outermost areas  of the human body: hair, fingernails, toenails, and the dead, outermost layers of the skin (the epidermis). This a complex of diseases caused  by  any  of  several  species of taxonomically related flamentous  fungi  in the genera Trichophyton, Epidermophyton, and Microsporum.

The various forms of dermatophytosis are referred to as Tineas or “ringworm.” Clinically, the tineas are classifed

• Tinea corporis (ringworm)
  • Tinea pedis (athlete’s foot)
  • Tinea capitis
  • Tinea barbae:
  • Tinea unguium (also known as onychomycosis).

Tinea corporis (ringworm):– Microsporum canis and Trichophyton mentagrophytes. Affects hairless skin. Tinea pedis (athlete’s foot):– T. rubrum, T. mentagrophytes, and Epidermophyton jloccosum. Affects mainly the lower legs. Tinea capitis: T. tonsurans and M canis.the scalp, eyebrows, and eyelashes.  Tinea barbae: T. rubrum and T.mentagrophytes. Beard ringworm. Tinea unguium (also known as onychomycosis).: T rubrum, T mentagrophytes, and E.floccosum. Affect the nails.

Mode of transmission

Superficial mycoses (Dermatomycoses) are infections that are transmitted directly by human contact with contaminate bodies

Prevention

Regular disinfection of showers and wardrobes can contribute to prevention of athlete’s foot, a very frequent infection