Text Chapter 18 has a nice set of tables withcharacteristics of the major prokaryotic groups

Title

•Text

Tree of Life

Microbe(s) of the Day: Deep-branching thermophilesAquificales and Thermotogales

•They are thought to have diverged from other bacteria early (thus similar to the earliest bacteria, perhaps).

•Oxidize (eat) hydrogen, making water in the process 2H2+O2 =2H20.

•Live at high temperatures (50 to 90oC) in hot springs, hydrothermal vents, hot muds, etc.

•Aquifex and Thermatoga species have acquired MANY of their genes by horizontal gene transfer from Archea and other groups of bacteria.

•Recent work by UConn microbiologists (Ken Noll, Peter Gorgarten and their students) suggest that Thermatoga species may not be belong at the base of the bacterial tree, but with the Firmicutes instead (Bacillus, Clostridium)

Microbe(s) of the Day: Deep-branching thermophilesAquificales and Thermotogales

Thermocrinis ruber in a Yellowstone hot spring

Thermotoga maritima wwwuser.gwdg.de/%7Eappmibio/research_liebl.html

Toga

Title

•Text

Tree of Life

Microbe(s) of the Day: Cyanobacteria•Grow a single cells, clusters, filament or sheets (see morphology lecture)

•Photosynthetic bacteria (once called “blue-green algae”) that produce O2 as a product of photosynthesis. Electrons are needed for photosynthesis and they are taken from water:H2O--> 4H+ + O2. This is called “oxygenic photosynthesis”. And it was the process that originally produced O2 in Earth’s atmosphere, 2.3 billion years ago (more later in the course).

•Many can convert (fix) atmospheric N2 into NH3. This process in inactivated by O2 (think about the point above), and is therefore done when O2 is lacking, or in specialized cells called “heterocysts” where the fixation is protected from O2.

•Cyanobacteria often contain internal compartments (most prokaryotes do not)-Thylakoid: membrane in which the photosynthetic machinary is embedded-Carboxysome: a compartment in which CO2 is fixed into carbohydrates-Lipid bodies that are storage compartments for energy-rich compounds-Gas bodies that help the bacteria float at the right depth in water, in order to collect light

Microbe(s) of the Day: Cyanobacteria•Many Cyanobacteria are symbionts with higher organsms such as lichens, plants and sponges:

•Many sponge species have their own specialized Cyanobacterial symbionts that provide fixed carbon and nitrogen. Sponges are sources of many interesting compounds that have antibacterial and anti-cancer properties. Many of these are actually made by the sponges cyanobacterial symbionts.

Lobaria pulminaria (Lung lichen)

Lobaria pulminaria (Lung lichen)Cross section

A B

C

D

A. Sponges of the Dysidea group (www.pbase.com)B. Oscillatoria spongeliae (www. asturnatuar.com)C. Fish killing cyanobacterial/sponge metabolites (see Ridley_ChemBiol_2005)D. Antibacterial cyanobacterial/sponge metabolites

Title

•Text

Tree of Life

Microbe(s) of the Day:Firmicutes-endospore formers

-Gram+ organisms with low amount of G and C in their genomes (“low GCs”)-Best know are Bacillus and Clostridium species

•Bacillus can grow aerobically and anaerobically•Clostridium species are strict anaerobes

-Both types form endospores (resistant spores that form inside the bacteria)

Most famous Bacillus species:•B. subtilus: model organism for Gram+ bacteria•B. anthracis: the anthrax bacterium. Purified endospores were used in the2001 anthrax mailings•B. thuringiensis (B.t) and B. popilliae: forms crystals of a toxin which kills many insects larvae. You can buy either to sprinkle on your lawn to take care of grubs.

B. popilliae sporesfor Japanese beetlecontrol -->

Bt toxin crystalsB.t.

Microbe(s) of the Day:Firmicutes-endospore formers

-Clostridium species are club shaped during spore growth, and are best know for the diseases they cause:

C. tetani: causes tetanus by making a toxin that causes muscles to seize up (read about it here : http://en.wikipedia.org/wiki/Tetanus). C. tetani will grow in anaerobic wounds (like punctures). That’s why you get a tetanus booster shot after such injuries.

C. botulinum: causes botulism poisoning (and is the source of BoTox). Organisms grow in anaerobic, non-acidic environments. Canned goods that are non-acidic (beans) and that not heated to temps high enough to kill the organisms are often the source of outbreaks. http://en.wikipedia.org/wiki/Botulism

C. difficile: causes severe diarrhea, often when other bacteria in the intestine are killed during antibiotic treatment.

Microbe(s) of the Day: Non-spore forming Firmicutes

Microbe(s) of the Day: Non-spore forming Firmicutes

-Lactic acid bacteria: Cannot use O2 as an electron acceptor. They ferment and make a variety of acids including lactic acid. These bacteria are often used in making fermented milk products like yogurt and cheeses.

-Staphylococcus sp. are commonly found on the skin. These are salt tolerant and many of them are pathogenic. Some of the most serious infections are caused by Staphylococcus sp. that are resistant to almost all antibiotics used to treat them. These are a serious public health threat.

-Streptococcus sp. are often found in the oral cavity and can also cause serious disease including strep throat (not too serious), pneumonia, scarlet fever and sometimes severe, quickly moving, tissue damage (necrotizing fasciitis) .

Microbe(s) of the Day:Non-spore forming Firmicutes

-Mollicutes: bacteria that lack a cell wall. Best studied are the Mycoplasmas. These are small, have some of the smallest genomes known in free-living organisms (~500 genes). They need few genes because they only live in association with hosts which provide them with nutrients

•Mycoplasma species can cause disease: Mycoplasma pneumoniae: “walking pneumonia”, meningitis Mycoplasma genetalium: discovered in 1980, causes STDs

Microbe(s) of the Day: the proteobacteria ( subgroup)

All proteobacteri are Gram -

The -prots are a large, well studied and extremely diverse group. They include:

•Photoheterotrophs: bacteria that can use light for energyand organic molecule for carbon. Often called “purple bacteria”•Pigmented when photosynthesizing.•Usually photosynthesize when in anaerobic environments•Found in water and soils. •Examples: Rhodobacter, Rhodopseudomonas

These are growing or were collected where waterswere anaerobic, but still irradiated with light

Microbe(s) of the Day: the proteobacteria ( subgroup)

All proteobacteri are Gram -

The -prots are a large, well studied and extremely diverse group. They include:

•Methanotrophs: bacteria that can oxidize 1-carbon compounds such as methanol or methane. One widely spread group is the Methylobacterium genus. These are found in soil, water and are easily isolated from plant leaves.

Clover leaf pressed into a petri plate with methanol as the carbon source.Enriched for Methylobacterium sp.

www.oeb.harvard.edu/faculty/marx/model-system.htm

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day:

Microbe(s) of the Day: