slide1 l.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Microbial Diversity Gram-Negative Strategies for Survival PowerPoint Presentation
Download Presentation
Microbial Diversity Gram-Negative Strategies for Survival

Loading in 2 Seconds...

play fullscreen
1 / 30

Microbial Diversity Gram-Negative Strategies for Survival - PowerPoint PPT Presentation


  • 192 Views
  • Uploaded on

Microbial Diversity Gram-Negative Strategies for Survival. Nitrosomonas vs. Pseudomonas Specialist vs. Jack-of-all-Trades. Nitrosomonas europaea Gram-negative, chemoautotroph Specializes in ammonia oxidation. These bacteria are important in

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Microbial Diversity Gram-Negative Strategies for Survival' - jean


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

Microbial Diversity

Gram-Negative Strategies for Survival

Nitrosomonas vs. Pseudomonas

Specialist vs. Jack-of-all-Trades

slide2

Nitrosomonas europaea

  • Gram-negative, chemoautotroph
  • Specializes in ammonia oxidation. These bacteria are important in
  • the treatment of industrial and sewage waste in the first step of
  • oxidizing ammonia to nitrate.
  • NH3 NO2 NO3
  • Found in soil, freshwater, sewage, the walls of buildings and on the
  • surface of monuments especially in polluted areas where air contains
  • high levels of nitrogen compounds.
  • Problematic because can reduce availability of nitrogen to plants and
  • hence limit CO2 fixation.Also may contribute significantly to the global
  • production of nitrous oxide.
  • N. europaea strain Schmidt Stan Watson is now completely sequenced.
  • 2715 predicted genes, 2.80 x 106 bp
  • overall G+C content = 50.8%
slide3

Pseudomonas aeruginosa

  • Gram-negative, chemoheterotroph
  • Versatile
  • Found in soil, marshes, coastal marine habitats,
  • on plants and animals
  • Problematic for cystic fibrosis, burn victims,
  • cancer, ICU patients
  • P. aeruginosa PAO1 is now completely sequenced.
  • - 5570 predicted genes
  • - 6.3 x 106 bp (largest sequenced genome to date)
  • - overall G+C content = 66.6%
  • - isolated regions with lower G+C content may be result of recent
  • horizontal gene transfer
  • - > 500 genes are transcriptional regulators or environmental
  • sensors. Has more than twice the number of two-component
  • regulators than E. coli or B. subtilis.
slide4

Question??

Which of these microbes would you choose as a candidate for potential new natural products or activities?

Nitrosomonas vs. Pseudomonas

slide7

Sequence map of Pseudomonas aeruginosa PAO1

phe genes

rhl genes

We can use these maps to gather information on genes of interest.

slide9

1223072

3792289

3889743

slide10

16s rDNA tree of biosurfactant-producing bacteria

Sulfolobus

Acinetobacter

P. putida

P. aeruginosa

Burkholderia

Halomicrobium

Stenotrophomonas

Alcanivorax

Agrobacterium

Marinobacter

Klebsiella

Serratia

Acidithiobacillus

Actinoplanes

Arthrobacter

Halobacterium

Microbacterium

Sp PCOB-2

Corynebacterium

Gordonia

Flavobacterium sp36

Rhodococcus

Nocardia

Streptococcus

Lactobacillus

Brevibacillus

Mycobacterium

0.1

B. subtilis

B. licheniformis

B. megaterium

slide11

A Problem:

  • Despite the fact that we appreciate the great diversity represented by the eubacterial kingdom, we currently have no way to translate this into interpreting associated activities.
  • Therefore, discovery of new natural products is inhibited:
  • we do not have adequate discovery tools
  • - we cannot interpret new gene sequences
  • - we do not have the capability to isolate unique
  • molecules from the environment at the levels normally
  • produced.
  • Yet the potential for new and economically important discoveries is extremely high.
  • An example…………
slide12

Pseudomonas in bioremediation

Pseudomonas aeruginosa makes a surfactant molecule, rhamnolipid:

O

C-CH2-CH - CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH3

-O

O

Ca2+

O=C

CH2

O

HO

CH3

O-CH- CH2 - CH2 - CH2 - CH2 - CH2 - CH2 - CH3

OH OR

Rhamnolipid monomer

Micelle formation at >CMC concentrations

CMC = 0.1 mM (50mg/L)

5 nm diameter

slide13

Synthetic Surfactant Industry Trivia

  • Estimated business of over $9 billion/yr
  • Cost: $1 to 5/kg
  • There is a Surfactant Science Series containing
  • > 50 volumes
slide14

Surfactant Industry

  • Agriculture
  • Cosmetics
  • Textile processing
  • Detergents (industry, home)
  • Building and construction (paving and concrete additive)
  • Metal Processing (e.g., ore concentration, rust removal)
  • Polymers (emulsion stabilizers, plasticizers)
  • Paint and protective coatings
  • Paper (resin removal, washing)
  • Petroleum production and products
  • Leather processing
  • Pharmaceuticals
  • Food (fat emulsifier, sugar processing, solubilization of
  • flavor oils)
slide15

Rhamnolipid Applications

  • Production of fine chemicals
  • Bioremediation
      • biodegradation of organics
      • biodegradation in the presence of toxic metals
      • removal of organics by flushing
      • removal of metals by flushing
  • Biological control
  • Antibiotic facilitator
slide16

Literature reports show variable effects

  • of surfactants on biodegradation
  • Aiba et al. (1969) synthetic surfactant -
  • Aronstein and Alexander (1992) synthetic surfactant +
  • Breuil and Kushner (1980) synthetic surfactant +/-
  • Churchill et al. (1995) synthetic surfactant +
  • biosurfactant +
  • Falatko and Novak (1992) biosurfactant +/-
  • Graves and Leavitt (1991) synthetic surfactant -
  • Jain et al. (1992) biosurfactant +
  • Oberbremer et al. (1990) biosurfactant +
  • Providenti et al. (1995) biosurfactant +/-
  • Thiem (1994) synthetic surfactant +/-
  • Whitworth et al. (1973) synthetic surfactant +
  • Zhang and Miller (1994;1995) biosurfactant +/-
slide17

1. Bioremediation of organic contaminants

  • Rates are constrained by low bioavailability
  • sorption
  • low aqueous solubility
  • aging
  • Biosurfactants increase bioavailability
  • solubilization
  • alteration of cell surface properties
slide18

The reason for variable results is that surfactants are usually added at high concentration (>> CMC), wherein they can:

be toxic to degrading cells

serve as a

preferred

carbon

source

Brazito soil

slide20

What are biosurfactant effects on cell surface?

  • Biosurfactant removes LPS from outer membrane of Gram-negative cells
  • Cell surface becomes more hydrophobic
slide24

Conclusion

Biosurfactants may be most effective at low concentration for remediation of organic contaminants.

slide25

2. Facilitating antibiotic activity

  • Antibiotic resistance is a serious and widespread problem. There are several reasons for antibiotic resistance. One that is particularly important for hydrophobic antibiotics is that cells do not take up the antibiotic.
  • Can rhamnolipid be used to facilitate the uptake of hydrophobic antibiotics?
slide27

Effect of rhamnolipid on dye (DMP) uptake

DMP = 2-(4-dimethylaminostyryl) 1-ethylpyridinium

slide29

Conclusions

These results suggest that asmall amphipathic molecule, like rhamnolipid, could be used in combination with an antibiotic as a therapy to decrease antibiotic dosage and increase antibiotic efficacy in a patient with a gram-negative infection.

slide30

Question:

How will we develop the tools necessary for systematic discovery of new natural products and other activities?