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Halobacteria

Published on Nov 18, 2015

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PRESENTATION OUTLINE

HALOBACTERIA

BY: CAMILLE, ALANNA, AND ELEANOR
Photo by oouinouin

HABITAT

  • Environments with salt, moisture, and large amounts of organic material are available
  • These include salt production facilities, salt mines, the Dead Sea, and the Great Salt Lake
  • Require at least a 2M NaCl solution to grow
  • Grow best in 4 to 5M NaCl solutions
  • Live mainly in harsh environments
Photo by szeke

CELL WALL

  • Surrounded by a single bilayer membrane
  • That is surrounded by an S-layer made from cell-surface glycoprotein
  • There's an excess amount of acidic amino acids in the proteins
  • This accounts for electrostatic shielding of -charges at a low concentration

MODE OF LIVING/SHAPE

  • Live in colonies
  • Rod shaped

SIZE

  • Genome size of 2Mb
  • There is 1 chromosome and 2 plasmids

MOBILITY

  • Uses flagella and gas vesicles to move
  • Swim towards green light, but away from damaging UV light
  • Can swim forward and backward in straight lines
  • Have the ability to reorient themselves
  • Use a process called chemotaxis to move towards a desired chemical

How do they obtain carbon/energy?
-Can't fix carbon from CO2
-Have 4 retinal proteins involved in light energy conversions and signal transduction
-3 ways to obtain energy

1) FERMENTATION OF ARGININE

  • Halobacteria generates ATP by its Arginine fermentation pathway

2) Photosynthesis
-bacteriorhodopsin, a light-driven proton pump, creates a proton gradient
-ATP synthase uses the energy of the proton gradient to drive ATP synthesis

3) Oxidation of various metabolites
-Oxidizes pyruvate which is channeled into the tricarboxylic acid cycle
-Halobacteria contains all 5 major complexes of the respiratory chain
-obligate aerobic

A RANGE OF DIFFERENCES

  • Optimal growth temp- 37-42 degrees Celsius
  • Need 2M NaCl solution to grow
  • Grow best in 4 to 5M NaCl solution
  • Sea water has .6M NaCl

EVOLUTIONARY RELATIONSHIPS

  • Halobacteria is more closely related to eubacteria than archaebacteria
  • Membrane transport systems have evolved for ionic movements
  • Cohesive forces are weak in their proteins, prevents aggregation in salt
  • Halobacteria can only thrive in high salt concentrations
  • The less oxygen in an environment, the more colorful they'll be

BIOLOGICAL IMPLICATIONS FOR CATEGORIZING

  • Their habitats
  • Ex) halophiles because survive in high salinity
  • Genomes

Physiological implications for categorizing
-for prokaryotes, it depends on if there is peptidoglycan in their cell walls

Definition of the biological species concept
-a population whose members have the potential to interbreed in nature and produce viable, fertile offspring, however they cannot do the same with other populations

WHY DOES THIS NOT APPLY?

  • Prokaryotes reproduce asexually
  • They do not interbreed

Remember those cell walls I built?
Well, baby they're tumbling down
And they didn't even put up a fight
They didn't even make a sound
I found a way to let oxygen in
But, I never really had a doubt
Standing in the UV radiation of your halo
I got my salt now

It's like I've been awakened
Every rule I had you breakin'
It's the risk that I'm takin'
I ain't never gonna shut you out

Everywhere I'm looking now
I'm surrounded by your high NaCl solution
Baby, I can see your halobacteria
You know they're saving the revolution
You're everything I need and more
It's written all over your evolution
Baby, I can feel your halobacteria
Pray it won't fade away


I can feel your halo, bacter, ia
I can see your halo, bacter, ia
I can feel your halo, bacter, ia
I can see your halo, halo..bacteria
Halo, ooh ooh..

Halobacteria Haiku

It's amazing how
Halobacteria like
Such salty places