Eukaryotic Microbes PDF

EUKARYOTIC MICROBES Prepared by: Maria Noviel Dominguez, MD President Ramon Magsaysay State University College of Nursing EUKARYOTIC MICROBES § ALGAE § FUNGI - Characteristics and classification - Characteristics - Medical significance...

EUKARYOTIC MICROBES Prepared by: Maria Noviel Dominguez, MD President Ramon Magsaysay State University College of Nursing EUKARYOTIC MICROBES § ALGAE § FUNGI - Characteristics and classification - Characteristics - Medical significance - Classification - Medical significance § PROTOZOA § LICHENS - Characteristics - Classification and medical § SLIME MOULDS significance ALGAE  ALGAE CHARACTERISTICS AND CLASSIFICATION: § Algae are photosynthetic, eukaryotic organisms. § All algal cells consists of cytoplasm, a cell wall (usually), a cell membrane, a nucleus, plastids, ribosomes, mitochondria, and golgi bodies. -Some have a pellicle, a stigma, and/or flagella. § Range in size from unicellular microorganisms to large, multi-cellular. § May be arranged in colonies or strands. ALGAE § Algae produce energy by photosynthesis. -Some may use organic nutrients. § Most algal cell walls contain cellulose. § Depending on their photosynthetic pigments, algae are classified as green, golden, brown, or red algae. ALGAE üAlgae are an important source of food, iodine, fertilizers, emulsifiers, stabilizers and gelling agents for jams and culture media. Algae: Medical Significance § One genus of algae, Prototheca, is a very rare cause of human infections. § Causes protothecosis. § Algae in several other genera secrete toxic substances called phycotoxins. - Poisonous to humans, fish, and other animals. - If ingested by humans, the phycotoxins produced by the dinoflagellates the cause “Red Tides” can lead to a disease called paralytic shellfish poisoning. Algae: Protothecosis  Algae: Paralytic Shellfish Poisoning § Symptoms typically appear 30–60 minutes after ingesting toxic shellfish but can be delayed for several hours § Numbness and tingling of the face, lips, tongue, arms, and legs § Headache, nausea, vomiting, and diarrhea § Severe cases are associated with ingestion of large doses of toxin and clinical features such as ataxia, dysphagia, mental status changes, flaccid paralysis, and respiratory failure PROTOZOA PROTOZOA CHARACTERISTICS: § Protozoa are nonphotosynthetic, eucaryotic organisms. § Most protozoa are unicellular and free-living; found in soil and water. -Most protozoa are more animal-like than plant- like. -All protozoa cells possess a variety of eucaryotic structures/organelles. -Protozoa cannot make their own food; they ingest whole algae, yeasts, bacteria, and smaller protozoa for nutrients.  PROTOZOA § Protozoa do not have cell walls, but some possess a thickened cell membrane called “Pellicle”, which serves the same purpose – protection. § Some flagellates and ciliates ingest food through a primitive mouth or opening called a “Cytostome”. PROTOZOAN LIFE CYCLE 2 stages – a TROPHOZOITE and a CYST § The Trophozoite is the motile, feeding, dividing stage. § The Cyst is the nonmotile, dormant, survival stage. § Some protozoa are parasites. § Parasitic protozoa cause many human diseases, such as malaria, giardiasis, and trypanosomiasis. Protozoa are divided into groups, based on their method of LOCOMOTION: § Amebae move by means of pseudopodia “False Feet”. Example: Entamoeba histolytica, the cause of amebic dysentery. § Ciliates move by means of hairlike cilia. Example: Balantidium coli, the cause of balantidiasis. § Flagellates move by means of whiplike flagella. Example: Giardia lamblia, the cause of giardiasis. § Sporozoa have no visible means of locomotion. Example: Plasmodium spp., which cause malaria.  Protozoal Disease: Dysentery § Caused by Entamoeba histolytica § Inflammatory disorder of the intestine, especially the colon, that results in severe diarrhea containing mucus and/or blood in the feces. § Untreated, dysentery can be fatal due to massive dehydration. § Can be caused by bacteria, protozoans or parasitic worms.  Protozoal Disease: Balantidiasis § Caused by Balantidium coli § Only ciliate known to be capable of infecting humans § Swine are the primary reservoir hosts but humans can also be reservoirs § Most cases are asymptomatic. Clinical manifestations, when present, may be acute or chronic with abdominal symptoms associated diarrhea or dysentery  Protozoal Disease: Giardiasis § Pathogenic species that feed off the intestinal lining caused by Giardia lamblia (aka. G. intestinalis) § Infection results from eating food/drinking water contaminated by the organism – usually from feces. § Chronic infection may result in malnourishment, blocking absorption of food across their intestinal wall.  Disease: Malaria § Life-threatening disease caused by Plasmodium malariae protozoan parasites transmitted through the bites of infected mosquitoes. § Symptoms include fever, chills, and flu- like illness. § Left untreated can cause coma and death if progresses to cerebral malaria. FUNGI FUNGI CHARACTERISTICS: § The study of fungi is called mycology; scientists who study fungi are called mycologists. § Fungi are found virtually everywhere. § Some fungi are harmful, some are beneficial. § Fungi represent a diverse group of eucaryotic organisms that include yeasts, moulds, and fleshy fungi (e.g., Mushrooms). § Fungi are the “garbage disposers” of nature. § Fungi are not plants – they are not photosynthetic. FUNGI § Fungal cell walls contain a polysaccharide called chitin. § Some fungi are unicellular, while others grow as filaments called hyphae. -Hyphae intertwine to form a mass called mycelium. § Some fungi have septate hyphae (the hyphae are divided into cells by cross walls or septa). § Some fungi have aseptate hyphae (the hyphae do not have septa). FUNGI REPRODUCTION § Depending on the species, fungal cells can reproduce by budding. Hyphal extension, or the formation of spores. - There are 2 general categories of spores: § Sexual Spores § Asexual Spores (also called conidia) - Some fungi produce both asexual and sexual spores. Fungal Colonies and Terms Relating to Hyphae FUNGI CLASSIFICATION: § Classification of fungi is based primarily on their mode of sexual reproduction and the type of sexual spore they produce. § Deuteromycotina or Deuteromycetes include the medically important moulds such as Aspergillus and yeast such Candida Albicans. -Fungi in this phylum have no mode of sexual reproduction or the mode of sexual reproduction is not known.  Dimorphic Fungi § A few fungi, including some pathogens, can live as either yeasts or moulds, depending on growth conditions. This phenomenon is known as dimorphism and the fungi are called dimorphic fungi. -When grown in vivo at body temperature (37 degree Celsius), dimorphic fungi grow as yeasts and produce yeast colonies. -When grown in vitro at room temperature (25 degree Celsius), dimorphic fungi exist as moulds, producing mould colonies.  Dimorphic Fungi § Dimorphic fungi that cause human diseases include: - Histoplasma Capsulatum (Histoplasmosis) - Sporothrix Schenckii (Sporotrichosis) - Coccidioides Immitis (Coccidioidomycosis) - Blastomyces Dermatitidis (Blastomycosis) YEASTS § Yeasts are eucaryotic, unicellular organisms that lack mycelia. § Individual yeast cells, also referred to as blastospores or blastoconidia, can only be observed using a microscope. § Yeasts usually reproduce by budding, but occasionally by a type of spore formation. § A string of elongated buds is known as a pseudohypha (not really a hypha). § Some yeasts produce thick-walled, spore-like structures called chlamydospores (or chlamydoconidia). Microscopic Appearance of the Yeast Candida albicans A = Chlamydospores B = Pseudohyphae C = Budding yeast cells (Blastospores) YEASTS § Yeasts are found in soil and water and on the skins of many fruits and vegetables. -Yeast have been used for centuries to make wine and beer. -Saccharomyces cerevisiae is a yeast used in baking. -Candida albicans is the yeast most frequently isolated from human clinical specimens YEASTS Bacteria Yeast § Yeast colonies may be difficult to distinguish from bacterial colonies. § -A simple wet mount can be used to differentiate yeast colonies from bacterial colonies. § Yeasts are larger than bacteria and are usually oval-shaped. § Yeasts are often observed in the process of budding. § Bacteria do not bud. MOULDS § Often spelled “molds”. § Moulds are often seen in water and soil and growing on food. § Moulds produce cytoplasmic filaments called hyphae. § Aerial Hyphae extend above the surface of whatever the mould is growing on. § Vegetative hyphae grow beneath the surface. MOULDS § Moulds have great commercial importance. -Some produce antibiotics. Examples: Penicillium and Cephalosporium -Some moulds are used to produce large quantities of enzymes that are used commercially. -The flavor of cheese like bleu cheese, Roquefort, camembert, and limburger are due to moulds that grow in them. FLESHY FUNGI § Include mushrooms, toadstools, puffballs and bracket fungi. § Consist of a network of filaments or strands (the mycelium) that grows in soil or on rotting logs. § The fruiting body that grows above the ground forms and releases spores. § Some mushrooms are edible; dome are extremely toxic.  FUNGAL INFECTIONS § Also called mycoses. § You are more likely to get a fungal infection if you have a weakened immune system § Fungi can be difficult to kill. For skin and nail infections medication applied directly to the infected area. Oral antifungal medicines available for serious infections.  Disease: Mycoses Fungal infections of humans are categorized as Superficial Cutaneous Subcutaneous Systemic mycoses Superficial and Cutaneous Mycoses § Superficial mycoses - are fungal infections of the outermost areas of the human body hair, nails and epidermis. § Cutaneous mycoses - are fungal infections of the living layer of the skin, the dermis. -A group of moulds collectively referred to as dermatophytes cause tinea (“ringworm”) infections. -Note that “ringworm” infections have nothing to do with worms. -The yeast, Candida albicans, can also cause cutaneous, oral, and vaginal infections.  Subcutaneous and Systemic Mycoses Subcutaneous and systemic mycoses are more severe types of fungal infections. § Subcutaneous mycoses are fungal infections of the dermis and underlying tissues. Example: Madura foot. § Systemic mycoses are fungal infections of the internal organs of the body. -Spores of some pathogenic fungi may be inhaled with dust from contaminated soil or dried bird or bat feces. They may also enter through wounds of the hands and feet.  Disease: Mycoses in Immunocompromised Individuals § Examples of deep-seated pulmonary infections include blastomycosis, coccidioidomycosis, cryptococcosis, and histoplasmosis. § Inhalation of common bread moulds like Rhizopus and Mucor spp. can cause disease and even death in immunosuppressed patients. § Diagnosis of mycoses is accomplished by culture techniques and immunodiagnostic procedures. -Yeasts are identified using a series of biochemical tests. -Moulds are identified using a combination of macroscopic and microscopic observation. Disease: Blastomycosis § What is Blastomycosis? -Caused by fungus Blastomyces dermatitidis found in soil in the eastern and central US. -Infection occurs by inhalation of spores. Once inhaled, fungus grows and may disseminate through blood to other organs. § Pulmonary Blastidiomycosis -Resolves on its own in most people. In immune compromised can cause respiratory failure. § Disseminated Blastidiomycosis -If disseminates from lungs, can result in wart-like or recessed skin lesions (cutaneous blastidiomycosis) or damage to bones (osteoarticular blastidiomycosis). AIDS patients are prone to develop meningitis from infection. Opportunistic Fungal Pathogen Species: Aspergillus fumigatus § Can cause disease aspergillosis. § Has become leading infectious cause of death in leukemia and bone marrow transplant patients. § Can result in: - allergic reaction - pulmonary mass - systemic infection - can also exacerbate asthma Opportunistic Fungal Infection § Five things increase a persons risk of experiencing opportunistic mycoses: - Invasive medical procedures - Medical therapies that weaken the immune system - Certain preexisting conditions / Immunocompromised individuals LICHENS AND SLIME MOULDS LICHENS AND SLIME MOULDS § LICHENS are observed as colored, often circular patches on tree trunks and rocks. - Composed of an alga and a fungus living in a mutualistic relationship. - Classified as protists. § SLIME MOULDS are found in soil and on rotting logs. - Have both fungal and protozoal characteristics. - Classified as protists. HELMINTHS HELMINTHS § Helminths are parasitic worms that live inside their host. Example: hook worm, whipworm, pinworm, tapeworm and round worm. § Belong to the Kingdom Animalia. § 3 Stages of Helminth Life Cycle: the egg, the larva, and the adult worm § Receive nourishment and protection while disrupting their hosts’ nutrient absorption, causing weakness and disease. § Many types of helminths love in the digestive tract of their host - intestinal parasites.  Helminth: HOOKWORMS § Two species commonly infect humans: Ancylostoma duodenale and Necator americanus. § Infect > 600 million worldwide. § Eggs in fecally-contaminated soil mature into larvae. § Larvae penetrate skin of foot (sometimes causing “ground itch”), ride the lymph system to the right side of heart, and pumped into lungs, are coughed up, and are then swallowed. § Enter digestive system, and mature into adult worms in small intestines. § Worms suck blood voraciously. Cause anemia, loss of iron & protein, and damage mucosa. Helminth: HOOKWORMS Cutaneous larva migrans  Helminth: TAPEWORMS § Parasitic nematode worm that lives in small intestine of host. § Taeniasis is the infection of humans with adult tapeworm of Taenia saginata (beef) or Taenia solium (pork). § People with taeniasis may not know they have an infection because symptoms are usually mild or absent. § T. solium tapeworm infections can lead to cysticercosis, a disease that can cause seizures, so it is important to seek treatment. Helminth: TAPEWORMS Intestinal tapeworm Thank you!