MICROBIO: EUKARYOTES

Identify the specimen

Oscillatoria

cyanobacteria

blue-green

filamentous; unbranched

cylindrical cells arranged in a single row

no flagella; but gliding motility

distinctive oscillating/waving movement; nitrogen fixation

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Anabaena

cyanobacteria

blue-green

filamentous

cells in a single row resembling a string of beads

no flagella; gliding movement from slime secretion

presence of heterocysts for nitrogen fixation and akinetes

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Spirulina

cyanobacteria

blue-green

filamentous; spirally coiled

cells in a single row along the helix held together by a thin sheath

no flagella; gliding movement dependent on Ca2+ and Na+ ions

distinct pigment comes from phycocyanin

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Chlamydomonas

chlorophyta

green

spherical/ovoid

single

motile by means off two anterior flagella

has an eyespot (stigma) with photoreceptors for photosynthesis

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Eudorina

cholrophyta

green

spherical/ovoid colonies

colonies of 16 / 32 cells radially embedded within a matrix

highly motile; coordinated beating of the two flagella on each cell

each cell has a stigma; hollow colonies surrounded by a gelatinous matrix

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Pandorina

chlorophyta

green

globular/spherical colony

radial compacted mass; held together at their bases in a gelatinous mix

2 flagella on each cell to create the rolling motion of colony

each cell has an eyespot

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Gonium

chlorophyta

green

flat and spherical/curved colony

4/8/16 cells arranged in flat colonies (spherical/curved) held together by extracellular matrix

2 flagella per cell; pinwheel motion

exhibits phototaxis

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Cladophora

chlorophyta

green

branched filamentous colonies thallus

multinucleate cells arranged into uniseriate filaments

vegetative form non-motile; asexual zoospores have 4 flagella; sexual gametes have 2

forms cladophora balls; ability to grow attached or unattached freshwater and marine envi

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Chara

charophyta

green

thallus with main axis (w distinct nodes and internodes) and lateral branches

multicellular thallus

sessile organism; motile sperm

a stonewort; globules and nucules at nodes; calcification on their surfaces

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Oedogonium

chlorophyta

green

unbranched filaments

multicellular unbranched thallus

non-flagellated vegetative filaments; motile zoospore w ring of flagella

attach to substrates using a basal holdfast; apical caps (rings of old cell wall material left after cell division) indicate how many times a cell has divided

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Spirogyra

chlorophyta

green

unbranched filaments

cells attached end to end to form filament

non-motile; capable of phototaxis

helical ribbon-shaped chloroplasts spiral around large central vacuole in each cell

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Zygnema

charophyta

yellow-green; green

unbranched filaments

cell attached end-to-end to form unbranched filament

non-motile

non-flagellated, amoeboid gametes

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Vaucheria

xanthophyta

yellow-green (xanthophyll pigments)

branched, filamentous, tube-like thallus

coenocytic, aseptate thallus

sessile; motile zoospores and antherozoids

reserve food in the form of oil droplets, differing from the starch typical of other algae

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Ulorothrix

chlorophyta

green

unbranched filaments

uniseriate

non-motile; motile zoospores

girdle-shaped chloroplast; holdfast cell; cold temp

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Desmids

charophyta

green

common shapes: globular, disc-like, spindle-like, and star-shaped

typically unicellular; each cell divided into 2 semi-cells

lack flagella

distinctive mirror-image semicells divided by a median constriction or isthmus

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Scenedesmus

chlorophyta

green

cylindrical;ovoid;fusiform;lunate

aligned in a single row side by side

non-motile; no flagella

rigid, multi-layered cell wall with ornamentation (ridges, warts, spines); efficient at removing nitrogen and phosphorus from wastewater

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Pediastrum

chlorophyta

green

flat; disc-shaped circles/starlike

coloniall coenobium

nonmotile; motille spores and gametes

distinctive horn-like or bristle-like projections on its peripheral cells

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Closterium

charophyta

green

lunate/elongate; tips usually tapered

Singles

Non-motile

At the very tips of the cell, there are special vacuoles that contain vibrating crystals of barium or calcium sulfate, the function of which is currently unknown. 

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Entamoeba histolytica

Amoebozoa

Archamoebae

colorless

irregular/amoeboid (trophozoites); spherical (cysts)

single

active trophozoite stage is motile, pseudopodia (temporary projections)

Amebiasis

Prevention: Hygiene, food and water safety

Treatment: (initial) anti-parasitic drug e.g.metronidazolel → (luminal) for eliminating cysts

Life cycle:

1. Ingestion: Humans ingest mature cysts from contaminated food, water, or hands. 

2. Excystation: In the small intestine, the cyst excysts to release the motile trophozoite. 

3. Migration & Invasion: Trophozoites migrate to the large intestine, where they can invade the intestinal lining, causing amebic dysentery. 

4. Multiplication: Trophozoites multiply by binary fission, and some form cysts. 

5. Excretion: Cysts are passed in the feces, completing the cycle. 

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Balantidium coli

Ciliophora

Litostomatea

yellowish-green

ovoid/spherical

single cell

rapid movement due to trophozoite’s entire surface covered with cilia

Balantidiasis - an intestinal infection that is often asymptomatic but can manifest as diarrhea, dysentery, and abdominal pain

Strict adherence to good hygiene and proper sanitation especially in areas where pigs are raised, as they are a reservoir for the parasite. 

Treatment: Antimicrobials

Life Cycle

1. Ingestion:

   Humans become infected by ingesting the infective cysts through contaminated food or water. 

2. Excystation:

   Once in the small intestine, the cyst excysts, releasing the motile trophozoite. 

3. Colonization:

   The trophozoites then establish themselves in the mucosa of the large intestine. 

4. Replication:

   The trophozoites multiply in the large intestine. 

5. Invasion and Pathology:

   Some trophozoites can invade the colon wall, leading to ulceration and disease. 

6. Encystation:

   Trophozoites undergo encystation in the colon to produce infective cysts, which are then passed in the feces. 

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Giardia lamblia

Sarcomastigophora

Zoomastigophorea

colorless

(trophozoite) pear-shaped; (cyst) ovoid

Single (trophozoite 2 nuclei, cyst 4 nuclei)

trophozoite has flagella

Giardiasis - Diarrhea, abdominal cramps, bloating, gas, and fatty stools

Prevention: Hygiene, Water and Food Safety

Prescribed drugs

1. Ingestion: Humans ingest Giardia cysts, often from contaminated water or food.

2. Excystation: In the small intestine, exposure to digestive enzymes triggers the cysts to release motile trophozoites.

3. Trophozoite Activity: Trophozoites attach to the intestinal wall, reproduce by binary fission, and cause damage.

4. Encystation: As the parasite moves towards the colon, trophozoites transform into environmentally stable cysts.

5. Excretion: Cysts are passed in the feces, ready to infect another host

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Plasmodium vivax

Apicomplexa

Aconoidasida

colorless

Shape: 

• Sporozoites: Lancet-shaped.

• Trophozoites: Amoeboid, with an irregular, spreading cytoplasm.

• Gametocytes: Round to oval shapes.

Cell Arrangement: The parasites grow and reproduce inside red blood cells and liver cells. 

Motility: The parasites are non-motile. 

Found: transmitted by female Anopheles mosquitoes. 

Disease: P. vivax causes malaria, a febrile illness characterized by fever, chills, headaches, and digestive issues. 

Prevention:

• Mosquito control: Avoiding mosquito bites through the use of insect repellent and bed nets. 

• Antimalarial drugs: Chemoprophylaxis is used to prevent infection. 

Treatment:

• Blood stage treatment:

  Chloroquine is the standard treatment for the symptomatic malaria parasite in the blood. 

• Liver stage treatment:

  Primaquine is necessary to eradicate the dormant hypnozoite stage in the liver, which causes relapses. 

Life Cycle:

1. Mosquito to human transmission:

   An infected female Anopheles mosquito injects P. vivax sporozoites into a human host during a blood meal. 

2. Liver stage (Exoerythrocytic phase):

   Sporozoites migrate to the liver, where they multiply within liver cells (hepatocytes) and develop into liver-stage schizonts. Some may remain dormant as hypnozoites for long periods. 

3. Merozoite release:

   Rupturing schizonts release merozoites into the bloodstream. 

4. Blood stage (Erythrocytic phase):

   Merozoites infect red blood cells (specifically reticulocytes), where they develop into trophozoites, and then into schizonts. 

5. Rupture and re-infection:

   The schizonts rupture, releasing more merozoites to infect new red blood cells, repeating the cycle and causing symptoms. 

6. Gametocyte formation:

   Some parasites develop into gametocytes, which are then ingested by another mosquito during a blood meal. 

7. Mosquito sexual reproduction:

   Inside the mosquito, gametocytes undergo sexual reproduction to form sporozoites, which migrate to the salivary glands, completing the life cycle. 

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Trichomonas vaginalis

Trichomonada

Parabasalia

Colorless

pear-shaped (pyriform) or oval

single

Motility: 

• highly motile due to four anterior flagella and a posterior flagellum attached to an undulating membrane, giving it a jerky motion.

Found: 

• Resides in the lumen and mucosal surfaces of the urogenital tracts of humans, predominantly the vagina, urethra, and prostate.

Trichomoniasis, a sexually transmitted infection; foul-smelling yellow-green discharge, itching, and dysuria

Prevention: Safe sex practices, such as using condoms; Treatment of sexual partners;

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