MICROPARA

• Algae


  Photosynthetic, eukaryotic organisms classified in the Protista kingdom

  
• Phycology


  The study of algae

  
• Phycologist (or algologist)


  A person who studies algae
• Components of algal cells

  • Cytoplasm
  • Cell wall (usually)
  • Cell membrane
  • Nucleus
  • Plastids
  • Ribosomes
  • Mitochondria
  • Golgi bodies
• Additional components some algal cells have

  • Pellicle (a thickened cell membrane)
  • Stigma (a light-sensing organelle, also known as an eyespot)
  • Flagella
• Most algal cell walls contain cellulose, a polysaccharide not found in the cell walls of any other microorganisms
• Types of photosynthetic pigments algae possess

  • Green
  • Golden (or golden brown)
  • Brown
  • Red

  
• Algae are more plantlike than protozoa, but they lack true roots, stems, and leaves

  
• Sizes of algae


  • Tiny, unicellular, microscopic organisms (e.g., diatoms, dinoflagellates, and desmids)
  • Large, multicellular, plantlike seaweeds

  
• Algae may be arranged in colonies or strands and are found in freshwater and salt water, in wet soil, and on wet rocks

  
• Diatoms


  Tiny, usually unicellular algae that live in both freshwater and seawater and are important members of the phytoplankton

  
• Over 200 genera of living diatoms are known
• Diatomaceous earth


  Naturally occurring soft rock consisting of fossilized remains of diatoms, easily crumbled into a fine white powder
• Uses of diatomaceous earth

  • Filtration aid
  • Mild abrasive in products like metal polishes and toothpaste
• Diatoms have been investigated for use as drug delivery systems in medicine, and their potential use in nanotechnology has drawn great interest
• Dinoflagellates


  Microscopic, unicellular, flagellated, often photosynthetic algae that are important members of the phytoplankton

  
• Dinoflagellates are responsible for what are known as "red tides"
• Green algae include many different genera, all of which can be found in pond water

  
• Algae and protozoa found in pond water

  • Ameba sp.
  • Euglena sp.
  • Stentor sp.
  • Vorticella sp.
  • Volvox sp.
  • Paramecium sp.

  
• Examples of algae


  • Large seaweeds of various colors
  • Brown kelp (up to 10 m in length) found along ocean shores
  • Green scum floating on ponds
  • Slippery green material on wet rocks

  
• Uses of algae


  • Food source
  • Source of iodine and other minerals
  • Fertilizers
  • Emulsifiers for pudding
  • Stabilizers for ice cream and salad dressings
  • Gelling agent for jams
  • Nutrient media for bacterial growth
  • Source of biofuels
• Damage to water systems is frequently caused by algae clogging filters and pipes if many nutrients are present
• Protothecosis


  A very rare human infection caused by the alga Prototheca

  
• Protothecosis progression


  1. Prototheca enters wounds, especially on the feet, producing a small subcutaneous lesion that can progress to a crusty, warty-looking lesion

  2. If the organism enters the lymphatic system, it may cause a debilitating, sometimes fatal infection, especially in immunosuppressed individuals
• Algae in several genera secrete substances (phycotoxins) that are poisonous to humans, fish, and other animals
• Protozoa


  Eukaryotic organisms classified in the Protista kingdom, along with algae

  
• Protozoology


  The study of protozoa

  
• Protozoologist


  A person who studies protozoa
• Characteristics of protozoa


  • Unicellular (single-celled), ranging in length from 3 to 2,000 µm
  • Free-living organisms, found in soil and water
  • More animal-like than plantlike
• Eukaryotic structures and organelles in protozoal cells

  • Cell membranes
  • Nuclei
  • Endoplasmic reticulum
  • Mitochondria
  • Golgi bodies
  • Lysosomes
  • Centrioles
  • Food vacuoles

  
• Additional structures some protozoa possess

  • Pellicles
  • Cytostomes
  • Contractile vacuoles
  • Pseudopodia
  • Cilia
  • Flagella

  
• Protozoa have no chlorophyll and, therefore, cannot make their own food by photosynthesis
• Protozoan sources of nutrients

  • Ingesting whole algae, yeasts, bacteria, and smaller protozoans
  • Living on dead and decaying organic matter
• Some protozoa, including some flagellates and some ciliates, possess a pellicle, which serves the same purpose as a cell wall—protection
• Some flagellates and ciliates ingest food through a primitive mouth or opening, called a cytostome
• Paramecium spp.


  Common pond water ciliates that possess both a pellicle (thickened cell membrane) and a cytostome

  
• Contractile vacuole


  An organelle found in some pond water protozoa (such as amoeba and Paramecium) that pumps water out of the cell
• Stages in a typical protozoan life cycle

  • Trophozoite stage (motile, feeding, dividing stage)
  • Cyst stage (nonmotile, dormant, survival stage)
• Cysts are like bacterial spores in some ways, such as the presence of a thick outer wall
• Some protozoa are parasites that break down and absorb nutrients from the body of the host in which they live