Bacteria

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Bacteria
Archaea
Common ancestor of all species living today
Eukarya
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Are prokaryotes a monophyletic group?
Domain Eukarya
Eukaryotes
Figure 24.18
Korarchaeotes
Euryarchaeotes
Domain Archaea
Crenarchaeotes
UNIVERSAL ANCESTOR
Nanoarchaeotes
Proteobacteria
Chlamydias
Spirochetes
Domain Bacteria
Cyanobacteria
Gram-positive bacteria
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Everywhere! 500 species in mouth (300 described
and named) Total number of bacterial cells in/on
the human host out-number host cells by at least
100-fold. In the gut alone, the bacterial
population is 100 trillion and is composed of
between 500 and 1,000 different species
(http//www.nature.com/ajgsup/journal/v1/n1/pdf/
ajgsup20126a.pdf)
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8-13kmUpper Troposphere
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Microbiome of the upper troposphere Species
composition and prevalence, effects of tropical
storms, and atmospheric implications ( Science
Magazine-January 2013) airborne microorganisms
above the oceans remain essentially
uncharacterized, as most work to date is
restricted to samples taken near the Earths
surface. Here we report on the microbiome of low-
and high-altitude air masses sampled before,
during, and after two major tropical hurricanes,
Earl and Karl. Quantitative PCR and microscopy
revealed that viable bacterial cells represented
on average around 20 of the total ... The
samples from the two hurricanes were
characterized by significantly different
bacterial communities, revealing that hurricanes
aerosolize a large amount of new cells.
Nonetheless, 17 bacterial taxa, .were found in
all samples, indicating that these organisms
possess traits that allow survival in the
troposphere. The findings presented here suggest
that the microbiome is a dynamic and
underappreciated aspect of the upper troposphere
with potentially important impacts on the
hydrological cycle, clouds, and climate.
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• Extremely important!
• Some nasty
• During 14th c Black Death or Bubonic plague
  killed 25 of population..
• (other diseases tuberculosis, cholera Lymes etc
  )
• But most are beneficial..
• Mutualisms- generate nutrients that we need in
  our gut
• Nutrient cycling-decomposers..

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Archaea Thermophiles Halophiles Methanogens
https//www.uni-due.de/biofilm-centre/archaea/
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• Thermophiles..
• The current record is ..Pyrodictium occultum,
  survived 121 C (250 F) for an hour.
• Some living at 170 C (338 F) around volcanic
  vents in ocean (J. Parkes).
• Early life on Earth hyperthermophile?

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• Extreme Halophiles
• Tolerate salt concentrations exceeding 15
• Most are photosynthetic autotrophs but not using
  chlorophyll
• Use bacteriorhodopsin
• (which uses all light except for purple, making
  the cells appear purple).

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Methanogens-common in many areas Release methane
Why do we hear about methane these
days? Anaerobic In gut of cattle, termites and
humans In sewage treatment facilities
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Methanogens in Human Health and
Disease Mark Pimentel MD1, et al. (2012)1GI
Motility Program, Cedars-Sinai Medical Center,
Los Angeles, California, USA There is growing
evidence that host/microbial interactions within
the gut can have a profound impact on human
health and disease in fact, the intestinal
microflora have been shown to influence the
innate physiology, biochemistry, immunology,
maturation of the vasculature, and gene
expression in a host. Although most research has
focused on gut bacteria, current evidence
suggests that the Archaeaan ancient domain of
single-celled organismsare resident within the
gut in high numbers, and have direct and indirect
effects on the host. In particular, the
methanogens are an essential component of luminal
intestinal microbial ecosystems. Methanogens
oxidize hydrogen to produce methane and ensure
more complete fermentation of carbohydrate
substrates, leading to higher production and
adsorption of short-chain fatty acids, which may
lead to obesity. Methane, the key product of
carbohydrate fermentation by the methanogens, has
long been thought to produce no ill effects in
humans aside from gaseous distention. However,
recent evidence has linked methane production to
the pathogenesis of constipation and irritable
bowel syndrome (IBS), as well as obesity. In
particular, a significant percentage of patients
with IBS and constipation excrete methane,
suggesting an overabundance of methanogenic
archaea in their gut. Methane by itself may
influence intestinal transit and pH and
facilitate development of constipation. If
methane has a direct or indirect effect on
intestinal transit, attempting to manipulate
methanogenic flora may serve as a novel
therapeutic option. Thus, understanding
methanogens and their role in gut
function/dysfunction is vital to our
understanding of human health and disease.
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• Behavior
• Getting around..
• Flagellum or flagella
• Analogous or homologous?
• Secrete mucous (chemicals-ooze around)

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Figure 24.10
Flagellum
20 nm
Filament
Hook
Motor
Cell wall
Peptidoglycan layer
Plasma membrane
Rod
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2. Show photo, chemo, geotaxis. 3.
Endospores-packages chromosome in tough coat
(Anthrax)
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4. Bacteriocins- chemical weapons that kill or
inhibit other bacteria Galvez A, Lopez RL,
Abriouel H, Valdivia E, Omar NB. Crit Rev
Biotechnol. 200828(2)125-52. Area de
Microbiologia, Facultad de Ciencias
Experimentales, Universidad de Jaén, Jaén, Spain.
agalvez_at_ujaen.es Bacteriocins are antimicrobial
peptides or proteins produced by strains of
diverse bacterial species. The antimicrobial
activity of this group of natural substances
against foodborne pathogenic, as well as spoilage
bacteria, has raised considerable interest for
their application in food preservation.
Application of bacteriocins may help reduce the
use of chemical preservatives and/or the
intensity of heat and other physical treatments,
satisfying the demands of consumers for foods
that are fresh tasting, ready to eat, and lightly
preserved. In recent years, considerable effort
has been made to develop food applications for
many different bacteriocins and bacteriocinogenic
strains. Depending on the raw materials,
processing conditions, distribution, and
consumption, the different types of foods offer a
great variety of scenarios where food poisoning,
pathogenic, or spoilage bacteria may proliferate.
Therefore, the effectiveness of bacteriocins
requires careful testing in the food systems for
which they are intended to be applied against the
selected target bacteria. This and other issues
on application of bacteriocins in foods of dairy,
meat, seafood, and vegetable origins are
addressed in this review.
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• 5. Quorum sensing
• Release and detect chemical pheromones to gauge
  their population density
• When lots of neighbors (a quorum) a group
  behavior is triggered ..
• bioluminesce
• attack
• Bacterium that causes Cholera does this

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• 6. Individually and in colonies-Biofilms!
• Typically multispecies mats stuck to a solid
  surface.
• Harmful in some cases (Cystic fibrosis).

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Kolenbrander, P. Andersen, R. Blehert, D. Palmer,
R. Microbiol Mol Biol Rev. 2002 September 66(3)
486505. Communication among Oral Bacteria
Development of the oral microbial community
involves competition as well as cooperation among
the 500 species that compose this community.
Sequential changes in populations of bacteria
associated with tooth eruption as well as with
caries development and periodontal disease states
are known. Temporal changes in populations of
bacteria on tooth surfaces after professional
cleaning are ordered and sequential. Such
sequential changes must occur through attachment
and growth of different bacterial species. With
the attachment of each new cell type, a nascent
surface is presented for the attachment of other
kinds of bacteria, resulting in a progression of
nascent surfaces and concomitant changes in
species diversity . Such coordination indicates
communication. In the absence of communication,
these orderly changes would be random. Due to the
dynamics of growth and adherence, the bacterial
populations in the oral cavity are constantly
changing, even during the intervals between
normal daily oral hygiene treatments. It is
unlikely that the various species within oral
biofilms function as independent, discrete
constituents rather, these organisms function as
a coordinated community that uses intra- and
interspecies communication.
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• 8. Reproduction
• Binary fission
• No sexual reproduction
• Mutation
• Conjugation
• share a plasmid
• Transformation
• Transduction
• phage infection

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All of these processes are Lateral Gene
Transfer Also called Horizontal gene
transfer So this is not like us we have
vertical transmission!
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• Genome
• 1/1000 as much DNA as eukaryotes
• One double stranded circular DNA molecule
• Additional PLASMIDS
• Replicate independently

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Figure 24.12
Chromosome
Plasmids
1 ?m
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Nutrient Cycling elements move between biological
and physical parts of ecosystems Legumes add
nitrogen to the soil Rhizobium species fix
nitrogen (each legume may have its own).
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Figure 24.22
Even non-legumes do better in soils with some
strains of bacteria added
1.0
0.8
0.6
Uptake of K by plants (mg)
0.4
0.2
Seedlings growing in the lab
0
Strain 1
Strain 2
Strain 3
No bacteria
Soil treatment
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• Humans..
• Many are mutualistic
• (vitamins in gut)
• Many are commensual
• (neither hurt nor harm us)
• Others are parasitic
• (neg. effects on us-Lyme disease)
• Normal flora-keep out disease causing bacteria

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Random addition 1 Gram staining.. Purple
positive (have larger quantities of peptidoglycan
in cell wall-considered simpler) Gram negative
pink (more complex outer membrane-more dangerous
-more resistant to antibiotics)
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Random addition 2 The largest prokaryote, next
to a fruit fly-almost 1mm in diameter. Sulfur
Pearl (Thiomargarita namibiensis) from Namibia,
inhabits the sediments along the west coast of
Africa. (microbe garden website)
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Random addition 3 Bloom of cyanobacteria
MN Pollution Control Agency Severe blue-green
algal blooms typically occur on lakes with poor
water quality (high in nutrients), and look like
green paint, pea soup, or a thick green cake (see
photo gallery below for examples). HAB often
result in extremely low water clarity (less than
1 foot). There is no visual way to predict the
toxicity of an algal bloom
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Random addition 4 We use these
organisms-Bioremediation!
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Random addition 5 Mutualism bacterial
headlights
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• Random addition 6 tubeworms !
• no mouths, no stomachs, and no intestines
• bodies house billions of bacteria that feed them
• (convert hydrogen sulfide
• from the hydrothermal
• vents into molecules that
• serve as usable nutrients)
• eight feet long

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of Samples resistant microbiology.mtsinai.on.ca/
tibdn/data/figure3.jpg Goossens The Lancet
The study showed that "antibiotics will have a
tremendous effect on normal flora microbes
which will exist for at least six months"