Bacteria
Archaea
Common ancestor
of all species living
today
Eukarya
Eukaryotes
Figure 24.18
Euryarchaeotes
Crenarchaeotes
UNIVERSAL
ANCESTOR
Nanoarchaeotes
Domain Archaea
Korarchaeotes
Domain
Eukarya
Are prokaryotes a
monophyletic group?
Proteobacteria
Spirochetes
Cyanobacteria
Gram-positive
bacteria
Domain Bacteria
Chlamydias
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)
8-13km=Upper Troposphere
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 Earth’s 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
Extremely important!
Some nasty…
•During 14th c Black Death or Bubonic plague killed 25%
of population..
(other diseases tuberculosis, cholera Lyme’s etc )
But most are beneficial…..
•Mutualisms- generate nutrients that we need in our gut
•Nutrient cycling-decomposers..
Archaea
Thermophiles
Halophiles
Methanogens
https://www.uni-due.de/biofilm-centre/archaea/
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?
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).
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
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 Archaea—an ancient domain of single-celled organisms—are
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 shortchain 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.
Behavior
1. Getting around..
Flagellum or flagella
Analogous or homologous?
Secrete mucous (chemicals-ooze around)
Figure 24.10
Flagellum
Filament
Hook
Motor
Cell wall
Plasma
membrane
Rod
Peptidoglycan
layer
20 nm
2. Show photo, chemo, geotaxis.
3. Endospores-packages chromosome in tough
coat (Anthrax)
4. Bacteriocinschemical “weapons” that kill or inhibit other bacteria
Galvez A, Lopez RL, Abriouel H, Valdivia E, Omar NB.
Crit Rev Biotechnol. 2008;28(2):125-52.
Area de Microbiologia, Facultad de Ciencias Experimentales, Universidad de Jaén, Jaén, Spain. agalvez@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.
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
6. Individually and in colonies-Biofilms!
Typically multispecies mats stuck to a solid surface.
Harmful in some cases (Cystic fibrosis).
Kolenbrander, P. Andersen, R. Blehert, D. Palmer, R. Microbiol Mol Biol Rev. 2002 September; 66(3):
486–505.
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.
8. Reproduction
Binary fission
No sexual reproduction
Mutation
Conjugation
share a plasmid
Transformation
Transduction
phage infection
All of these processes are…
Lateral Gene Transfer…
Also called Horizontal gene transfer…
So this is not like us…… we have vertical
transmission!
Genome
1/1000 as much DNA as eukaryotes
•One double stranded circular DNA molecule
•Additional PLASMIDS
•Replicate independently
Figure 24.12
Chromosome
Plasmids
1 m
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).
Uptake of K by plants (mg)
Even non-legumes do better in soils with some
strains of bacteria added
1.0
0.8
0.6
0.4
0.2
Seedlings growing in the lab
0
No
Strain 1 Strain 2 Strain 3
bacteria
Soil treatment
Figure 24.22
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
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)
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)
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
Random addition #4
We use these organisms-Bioremediation!
Random addition #5 Mutualism: bacterial
“headlights”
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
% of Samples
resistant
microbiology.mtsi
nai.on.ca/tibdn/dat
a/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"