Biology Lecture 11: Bacteria and Protists

Eukaryotic Microorganisms

• Bacteria and protists are prominent members of ecosystems, model systems, and industrial applications.
• Protists represent a majority of the diversity in the Eukarya domain, and some are human and plant pathogens.

Common Features of Eukaryotic Cells

• Eukaryotic cells have sexual and asexual reproduction, meiosis, and mitosis.
• They have a membrane-bound nucleus, plasma membranes (lipid bilayers), and membrane-enclosed organelles.
• Many have cell walls, and their organelles include endoplasmic reticulum (ER), Golgi apparatus, mitochondria, and ribosomes.

Protists

• Protists are a general term for eukaryotic microorganisms that don't fit into any other kingdom-level group.
• They are mostly unicellular, with over 60,000 different life forms, including algae, slime molds, and protozoa.
• Protists are important links in food chains and are found in aquatic habitats, such as plankton, radiolarians, diatoms, and foraminiferans.

Chlamydomonas

• Chlamydomonas is a unicellular green alga with a cell wall made of cellulose.
• It has oxygenic photosynthesis, is motile via two flagella, and has a stigma (eyespot) for phototaxis.

Dictyostelium

• Dictyostelium is a cellular slime mold with two types of nuclei: micronucleus and macronucleus.
• It has a life cycle that involves free-living amoeboid cells, aggregation, formation of a motile slug, and eventually, a fruiting body with spores.

Giardia

• Giardia is a protozoan parasite that causes giardiasis, a human disease.
• It has a life cycle that involves cysts, trophozoites, and attachment to the intestine, leading to severe diarrhea and fluid loss.

Naegleria fowleri

• Naegleria fowleri is a free-living, aquatic amoeba that causes primary amebic meningoencephalitis (PAM).
• It is a thermophile that can cause brain swelling and death.

Alveolata

• The Alveolata group includes protists with an apical complex, such as dinoflagellates, apicomplexans, and ciliates.
• Dinoflagellates have two flagella in grooves, are toxic, and cause "red tides."

Cryptosporidiosis

• Cryptosporidiosis is a human disease caused by Cryptosporidium, an apicomplexan parasite.
• Oocysts are transmitted in contaminated water, and the disease is a common cause of waterborne illness.

Toxoplasmosis

• Toxoplasmosis is a human disease caused by Toxoplasma, an apicomplexan parasite.
• Oocysts are found in raw or undercooked meat, and cat feces, and can infect mice and humans.

Malaria

• Malaria is caused by four species of Plasmodium, an apicomplexan parasite.
• It is transmitted by the bite of an infected female Anopheles mosquito and causes severe disease worldwide.

Control, Prevention, and Treatment

• Malaria control involves mosquito control, wetland drainage, insecticides, and netting.
• Drugs include chloroquine, which blocks the parasite's ability to degrade hemoglobin, and Malarone, which blocks e- transport and pyridine synthesis.

Eukaryotic Microorganisms

• Bacteria and protists are prominent members of ecosystems, model systems, and industrial applications.
• Protists represent a majority of the diversity in the Eukarya domain, and some are human and plant pathogens.

Common Features of Eukaryotic Cells

• Eukaryotic cells have sexual and asexual reproduction, meiosis, and mitosis.
• They have a membrane-bound nucleus, plasma membranes (lipid bilayers), and membrane-enclosed organelles.
• Many have cell walls, and their organelles include endoplasmic reticulum (ER), Golgi apparatus, mitochondria, and ribosomes.

Protists

• Protists are a general term for eukaryotic microorganisms that don't fit into any other kingdom-level group.
• They are mostly unicellular, with over 60,000 different life forms, including algae, slime molds, and protozoa.
• Protists are important links in food chains and are found in aquatic habitats, such as plankton, radiolarians, diatoms, and foraminiferans.

Chlamydomonas

• Chlamydomonas is a unicellular green alga with a cell wall made of cellulose.
• It has oxygenic photosynthesis, is motile via two flagella, and has a stigma (eyespot) for phototaxis.

Dictyostelium

• Dictyostelium is a cellular slime mold with two types of nuclei: micronucleus and macronucleus.
• It has a life cycle that involves free-living amoeboid cells, aggregation, formation of a motile slug, and eventually, a fruiting body with spores.

Giardia

• Giardia is a protozoan parasite that causes giardiasis, a human disease.
• It has a life cycle that involves cysts, trophozoites, and attachment to the intestine, leading to severe diarrhea and fluid loss.

Naegleria fowleri

• Naegleria fowleri is a free-living, aquatic amoeba that causes primary amebic meningoencephalitis (PAM).
• It is a thermophile that can cause brain swelling and death.

Alveolata

• The Alveolata group includes protists with an apical complex, such as dinoflagellates, apicomplexans, and ciliates.
• Dinoflagellates have two flagella in grooves, are toxic, and cause "red tides."

Cryptosporidiosis

• Cryptosporidiosis is a human disease caused by Cryptosporidium, an apicomplexan parasite.
• Oocysts are transmitted in contaminated water, and the disease is a common cause of waterborne illness.

Toxoplasmosis

• Toxoplasmosis is a human disease caused by Toxoplasma, an apicomplexan parasite.
• Oocysts are found in raw or undercooked meat, and cat feces, and can infect mice and humans.

Malaria

• Malaria is caused by four species of Plasmodium, an apicomplexan parasite.
• It is transmitted by the bite of an infected female Anopheles mosquito and causes severe disease worldwide.

Control, Prevention, and Treatment

• Malaria control involves mosquito control, wetland drainage, insecticides, and netting.
• Drugs include chloroquine, which blocks the parasite's ability to degrade hemoglobin, and Malarone, which blocks e- transport and pyridine synthesis.

Eukaryotic Microorganisms

• Bacteria and protists are prominent members of ecosystems, model systems, and industrial applications.
• Protists represent a majority of the diversity in the Eukarya domain, and some are human and plant pathogens.

Common Features of Eukaryotic Cells

• Eukaryotic cells have sexual and asexual reproduction, meiosis, and mitosis.
• They have a membrane-bound nucleus, plasma membranes (lipid bilayers), and membrane-enclosed organelles.
• Many have cell walls, and their organelles include endoplasmic reticulum (ER), Golgi apparatus, mitochondria, and ribosomes.

Protists

• Protists are a general term for eukaryotic microorganisms that don't fit into any other kingdom-level group.
• They are mostly unicellular, with over 60,000 different life forms, including algae, slime molds, and protozoa.
• Protists are important links in food chains and are found in aquatic habitats, such as plankton, radiolarians, diatoms, and foraminiferans.

Chlamydomonas

• Chlamydomonas is a unicellular green alga with a cell wall made of cellulose.
• It has oxygenic photosynthesis, is motile via two flagella, and has a stigma (eyespot) for phototaxis.

Dictyostelium

• Dictyostelium is a cellular slime mold with two types of nuclei: micronucleus and macronucleus.
• It has a life cycle that involves free-living amoeboid cells, aggregation, formation of a motile slug, and eventually, a fruiting body with spores.

Giardia

• Giardia is a protozoan parasite that causes giardiasis, a human disease.
• It has a life cycle that involves cysts, trophozoites, and attachment to the intestine, leading to severe diarrhea and fluid loss.

Naegleria fowleri

• Naegleria fowleri is a free-living, aquatic amoeba that causes primary amebic meningoencephalitis (PAM).
• It is a thermophile that can cause brain swelling and death.

Alveolata

• The Alveolata group includes protists with an apical complex, such as dinoflagellates, apicomplexans, and ciliates.
• Dinoflagellates have two flagella in grooves, are toxic, and cause "red tides."

Cryptosporidiosis

• Cryptosporidiosis is a human disease caused by Cryptosporidium, an apicomplexan parasite.
• Oocysts are transmitted in contaminated water, and the disease is a common cause of waterborne illness.

Toxoplasmosis

• Toxoplasmosis is a human disease caused by Toxoplasma, an apicomplexan parasite.
• Oocysts are found in raw or undercooked meat, and cat feces, and can infect mice and humans.

Malaria

• Malaria is caused by four species of Plasmodium, an apicomplexan parasite.
• It is transmitted by the bite of an infected female Anopheles mosquito and causes severe disease worldwide.

Control, Prevention, and Treatment

• Malaria control involves mosquito control, wetland drainage, insecticides, and netting.
• Drugs include chloroquine, which blocks the parasite's ability to degrade hemoglobin, and Malarone, which blocks e- transport and pyridine synthesis.

Learn about eukaryotic microorganisms, including prominent members of ecosystems, bacteria and protists, and their importance in industry and as model systems.