Bacterial Morphology and Motility

• Bacterial shape, configuration, and motility are key characteristics.
• Slide types include wet mount, hanging drop, and fixed.

Slide Types

• Wet mount: The organism is alive.
• Hanging drop: The organism is alive and motility can be observed.
  • A concave side faces down when placing the coverslip.
  • The coverslip has 4 dots of petroleum, one on each corner.
• Fixed: The organism is dead, sterilized with flame, and stained with Methylene Blue.

Bacterial Shape

• Bacillus (bacilli pl.): Cylindrical-shaped bacterium usually straight rod.
• Coccus (cocci pl.): Spherical or oval-shaped bacterium.
• Spirillum: Spiral shaped bacterium.
• Vibrio: Curved rod.

Bacterial Configuration

• Staphylo: Irregular, often grape-like clusters.
• Strepto: Chain arrangement.
• Diplo: Paired arrangement.

Types of Bacterial Motility

• Flagellum (flagella pl., Latin= whip): Lash-like appendage that allows for locomotion and acts as a sensory organelle.
• Pilus (pili pl., Latin= hair): One type can facilitate gliding movement.
• Axial Filament: Cork-screw type motion.
• Brownian Motion: Movement generated by random thermal energy (fast-moving atoms) colliding into an object.
• Cyanobacteria: Group of predominantly photosynthetic, usually blue-green bacteria, nitrogen fixers.

Bacteria Looked at in the Lab

• Bacillus Subtilis
• Staphylococcus epidermidis
• Rhodospirillum rubrum
• Aliivibrio fischeri

Protists

• Alveolata
• Archaeplastida
• Excavates

Alveolata

• Primarily single-celled eukaryotes.
• Synapomorphy: Alveoli -> flattened membranous sacs or vesicles packed into a continuous supporting layer under the cell membrane, typically forming a pellicle.
• Micropores are used for pinocytosis -> ingestion of liquid into a cell Extrusive organelles like trichocysts are present.
• Lifestyles range from photoautotrophy to predation and parasitism.

Apicomplexa

• A group of obligate parasites.
• Synapomorphy: Apical Complex -> Is found at the apical end of the cell during certain stages (most notably the infective stage) with a Conoid at the end (a chemical drill bit).
• Mobile gametes are the only flagellated stage.
• Moves with a glideosome ->gliding motility.

Ciliophora

• Synapomorphies: Cilia -> Hair-like projections of cytoplasm.
  • Often shorter than flagella and present in high numbers.
  • Used for swimming, crawling, attachment, feeding and sensation + undulating motion.
• Cells have two dimorphic nuclei, one for sexual reproduction and one for asexual reproduction and controlling cell function.
• Is a ubiquitous predator in freshwater.
• Utilizes trichocysts as offense and defense.

Dinoflagellata

• Synapomorphies/Unifying traits.
• 2 flagella: One longitudinal flagellum (acts as a rudder) and one transverse flagellum (undulating motion).
• Nucleus is called a Dinokarvon-> Holds a ton of DNA.
• Xanthophyll pigment: A golden-brown photosynthetic pigment.
• Thecal plates exist.
• Red tides come from this.
• Uses pallium, peduncle, and trichocysts.

Archaeplastida

• Large group including land plants, red algae, and green algae.
• Synapomorphy: Plastids, primarily chloroplasts, surrounded by 2 membranes, suggesting direct development from cyanobacteria.

Chlorophyta

• Photosynthetic Organism primarily unicellular, big exception is Volvox.
• Uses Chlorophyll a and b, energy stored as starch.
• Alga is an artificial aggregation of organisms, not a taxonomic ranking.

Charophyta

• Closely related to land plants
• Conjugating green algae without flagella.
• Includes Spirogyra that has chloroplasts in spirals with a suspended nucleus.
• Desmids have a mirror image symmetry connected by a bridge (nucleus within bridge).

Rhodophyta

• Synapomorphies: a unique pigment called phycoerythrin, uses floridean starch as energy storage.
  • Rhodolith: sedimentary structure that can withstand wave action + erosion.
  • Genicula Flexible joints to withstand currents.
• Secretes calcium carbonate.
• Lives in greater depths at primary producers.
• Without flagella at any stage.

Differences in Algae.

• Different photosynthetic Chlorophyll a + b vs. phycoerythrin
• Lack of flagella in Rhodophyta vs Chlorohyta with flagellar movement Habitat
• a. Marine environment for Rhodophyta vs. both FW and marine for green algae

Excavates

• from a cavity
• Many have a depression in the cell used as a feeding groove.
• Have two or more flagella: one is used to beat the water/generate current to filter feed.
• Is mostly heterotrophic.
• Inhabit low oxygen envirinments.

Excavates - Euglenozoa

• Excavates' phylum.
• The flagella is a unifying characteristics. Adaptations:
• Stigma- photosensory structure for position in water column
• Flagella, proteinaceous strips of pellicle, feeding rods and veins are components of genus Euglena.