Coordinatingthe Raucous

Crowd:

Quorum Sensing Signals Affecting Microbial Social

Function

Overview

• Introduction to Quorum Sensing:

Acyl-Homoserine lactones (Acyl-HSLs)

• Occurrence, Structures and Characteristics

• Signal Synthesis and Degradation

Egland & Leadbetter

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Prototypical Acyl-HSL Mediated Quorum Sensing Systems

•Bacteria

Genes

“on”

Genes off”

Overall

Synthase(LuxI homologues) Acyl-Homoserine

Lactones (AHLs)

Regulator(LuxR homologues)

Quorum Regulated Genes

Details

Examples of Functions Regulated by Quorum Sensing:

• Light production

• Exopolysaccharide synthesis

• Extracellular enzymes synthesis: proteases, chitinases, pectinases,

elastases

• Antibiotic synthesis: carbapenem, cyanide, phenazines

• Biofilm formation

Examples of Environments from which Quorum Sensing Bacteria are

Isolated

• Marine animals: Gut tracts and light organs

• Clinical biofilms: lungs, urinary catheters

• Plant roots: nodules of legumes, crown galls

• Plant leaves: leaf wilt diseases

• Soils

Rotten Lettuce in your refrigerator? Rotten Lettuce in your refrigerator? It’s probaby due to a plant pathogen, It’s probaby due to a plant pathogen, (a (a Pseudomonas Pseudomonas or or ErwiniaErwinia species) species)

responding by quorum sensing responding by quorum sensing to acyl-HSLs. to acyl-HSLs.

Biological Quorum Signal Decay Mechanisms

Acyl-homoserine Lactone (AHL)

Acyl-homoserine (AHS)

Fatty Acid + Homoserine Lactone

+

Chemical Hydrolysis AHL Lactonase

BacillusAgrobacterium

KlebsiellaCO2

other products

AHL Acylase

Variovorax Ralstonia

Pseudomonas

Arthrobacter

ArthrobacterBurkholderia

1) ARE Acyl-HSL SIGNALS STABLE IN SOILS?

2) IS Acyl-HSL SIGNAL BIODEGRADATION RELEVANT TO QUORUM SENSING BACTERIA ?

In the laboratory as in nature:

- Bacteria can make and respond to Acyl-HSL signals.

- Bacteria can break them down and utilize them.

QUIZ! (14 pts)

1, Please name the primary generalized function of quorum sensing (QS). (2 pt)

2, What are four physiological processes are regulated by QS? (2 pts)

3, What are two completely different types of molecules that function in QS in different bacteria? (2 pts)

4, Please provide the generalized chemical structure of an acyl-homoserine lactone. (2 pt)

5, What types of bacteria make and respond to them? ( 2 pts)

6, How and why do these bacteria degrade these molecules? (2 pts)

7, What are the consequences of the loss of QS in general? (2 pt)

Bacteriology Final There are 126 pts total and 37 questions. Please write your name and number of lectures missed due to sickness on the first page of the exam.

Bacteriology Final: Short answers (29)

1.

1. Please provide 3 benefits resulting from the establishment and study of protein homologies. (3)

2. List 5 very different benefits to humans resulting from the study of bacteriology. (5)

3. What are the three best ways to control bacterial infectious diseases? (3)

4. Describe two forms of “jet propulsion” motility, and two forms of “crawling” or “twitching” motility in bacteria. (4)

5. Please list 5 unique characteristics of archaeal envelopes and their constituents that distinguish them from bacterial and eukaryotic envelopes. (5)

6. Name three conditions that are known to cause or allow bacteria and archaea to reduce the sizes of their genomes. (3)

7. You are infected with Bacillus anthracis while in the Tortuguero rain forest.Explain why you didn’t come down with anthrax until welcome week. (2)

8. What are 4 basic differences between the structures of and assembly mechanisms for flagella and pili? (4)

Bacteriology Final: Essay type (8)

9. What are the two principle modes of

energy generation observed for organoheterotrophic living organisms?

Be sure to list and describe four distinguishing features for each of these two processes.

Bacteriology Final: True/False (10)10. Prions are infectious particles that pathogenic bacteria secrete to cause disease

in the host animal organism.11. Mycolic acids in the outer membranes of Mycobacterium tuberculosis and Myco-bacterium leprae enhance resistance to antibiotics and therefore cause prolongation

of the human and animal diseases caused by these actinobacteria.12. The only human cells which are known to be immortal are germ and embryonic

cells.13. Mycoplasmas and their close relatives are the only known bacteria that do not

have peptidoglycan cell walls.14. Pili are able to transfer proteins and DNA from a male bacterium to female

bacteria.15. The presence of c-type cytochromes allows certain pili to function as nanowires,

transferring electrons from extracellular solid minerals to NAD+ or NADP+ in the bacterial cytoplasm.

16. In the presence of increasing concentrations of an attractant, a chemoreceptor binds the compound on the outside of the cell to activate dephosphorylation and methylation of the MCP receptor.

17. Catabolism involves breaking bonds in metabolites to generate ATP via substrate level phosphorylation.

for anabolism.18. Most kinds of photoauxotrophic bacteria can use molecular oxygen (O2) as the

electron donor.19. No archaeon is known to cause a disease in an animal, plant or fungus.

Bacteriology Final: Matching (mulitple answers are possible; 3 pts per organismal type)

2

020, What macromolecules are common to the envelopes of:

a, lipopolysaccharides

b, mycolic acidsA, Gram-negative bacteria c, ether lipids

d, ester lipids e, murineB, Low G+C Gram-positive bacteria f, teichoic acids

g, L-glycerol lipidsC, High G+C Gram-positive bacteria h, D-glycerol lipids

D, Archaea i, isoprenoid lipids

Bacteriology Final: Fill in the blanks. (1 pt per blank; 7 pts total)

21, Autotrophic bacteria that live in the caves in Tabasco, Mexico that do not require fixed carbon compounds are called ______________ where the compound ______________ serves as the electron donor for respiration.

22, Two metabolic pathways that produce ATP by substrate level phosphorylationare ______________ and ________________. To make a pmf from ATP the enzyme called the_______________ is required.

23, The primary pathway that generates a pmf or an smf as the primary source of energy is called the _________________, and the proteins that generate the pmf or smf are called _________________.

Bacteriology Final: ESSAY TYPE

(ten points each)

24, Show schematically and describe how peptides are believed to have evolvedinto complex group translocators of the phosphotransferase system (PTS). Pleaseexplain what is going on according to the scheme you present.

25, Describe the mechanistic (molecular) essence of any short term memory system(such as the one that allows E. coli to chemotax up an attractant concentration and down a repellent concentration). Use this chemotaxis system to exemplify the

process, but also indicate which elements are general to all memory systems, and which are specific to this one.

26.Please describe and show schematically how the F-type ATPase (ATP synthase), present in almost all living cells, interconverts chemical and chemiosmotic energy. Be specific about the molecular mechanism.

Bacteriology Final: Multiple Choice (multiple answers possible; 2 pts each)

27.Type I (ABC) a, can secrete only proteins b,bcan secrete proteins and DNA c, can secrete proteins, lipids and carbohydrates

28. Type II (Sec) d, uses ATP to energize secretion e, uses the pmf to energize secretion f, does not use energy

29.Type III ( Fla, Path) g, can insert proteins into the membrane

30. Type IV (Conj, Vir)

Bacteriology Final: Multiple choice (2 each)

31. Transduction

32. Conjugation

33. Transformation

34. Gene Transfer Agent

A,

A, involves an infectious agentB, involves type IV secretionC, is related to an infectious agent

D, the DNA donor always diesE, the DNA donor sometimes diesF, the DNA donor never dies,

Bacteriology Final (2)35. Define quorum sensing.

36. List 4 of its biological functions.

37. Give the names of three molecular types (different molecules).

Bacteriology Final:

CONGRATULATIONS; YOU’RE DONE!

Human Impact (H.I.) on the Environment: Final Exam

42 questions; 109 pts today.OVERALL: 48 questions; 144 pts. including 6 questions worth 35 pts of take home extra credit

H. I. Final ( Multiple Choice; multiple answers per questions; three points each)

11, What are the PRIMARY contributors to green house gas production?

A, DeforestationB, Burning of fossil fuelsC, AgricultureD, Cows belching and fartingE, Growing rice for the human population

2, Use of fertilizers containing nitrates can cause:

A, increased O2 concentrations in lakes and ocean deltasB, increased fish populations in lakes and ocean deltasC, increased algal growthD, decreased O2 content of lakes and ocean deltasE, decreased fish populations in lakes and ocean deltasF, eutriphication and putrification

H. I. Final(Multiple choice and fill in the blanks; there may be more than one answer. 3 pts each)

3, About how many mammals and birds are killed in the United States per year for human consumption?

A, 10 millionsB, 100 millionsC, 1 billionD, 10 billionsE, 3 brazilians

4, In the U. S. alone, the average beef cow is slaughtered at about ___________ years of age, the average pig at ___________ years, and the average dairy cow at __________ years.

5, What were the purposes of reinstating the Global Gag Rule in 2000?

A, To promote economic development through free tradeB, To prevent foreign family planning agencies from providing abortion counseling and referralsC, To diminish the incidence of AIDSD, To force standards on developing countries that were in need of financial aidE, To impose the standards of a religious minority on the world population

H. I. FinalShort answers, two OR three OR four OR five points each as indicated below

6, Name three ways Costa Rica has succeeded in conserving its rain forests. (3)

7, Please provide 4 observations that reflect the extent of current global warming. (4)

8, Regarding the Monte Verde Reserve, what are three negative consequences of eco-tourism? (3)

9, Name, define and cite the primary causes of two types of smog. (4)

10, According to Prof. Dave Woodruff, what is the # 1 cause of species extinction? Name three ways in which humans have caused this. (3)

11, The two most important things we can do to preserve biodiversity on Earth are to (1) _____________________, and (2) ______________________. (2)

12, What were 3 strategies used by the coal companies to make people question the scientific evidence concerning the occurrence of global warming? (3)

13, What were 5 strategies used FOX “News” to make viewers reject liberal views? (5)

H. I. Final14, According to Dr Tom English, what are the 5 principle causes of species extinction?(5)

TRUE/FALSE (1 pt each)

15, Over 70% of oil used by the U. S. is imported. 16, The George C. Marshall Institute used the same techniques to cause people to question (1) the harmful effects of cigarette smoking, (2) the consequences of ozone depletion, and (3) the catastrophic consequences of global warming.

17, Per unit protein, meat consumes roughly 10x the amount of fossil fuels and land , and 20x the amount of water than the production of the same amount of soy protein.

18, For the benefit of human health and the environment, and to promote an ethical life style, one should eat vegetarian diets.

19, Children who grow up in LA have 20% less lung capacity than children raised elsewhere.

20. Only 4% of corn grown in the US is used directly for human consumption.

H. I. FinalT/F cont.

21, Genetic variability correlates with species fitness. 22, Biogeochemical cycles are due more to bacterial activities than to human activities.

Essay type. (7 pts)

23. Compare and contrast China’s and Iran’s fight against overpopulation. What differences in tactics did they use? Did they achieve their goals? What do these observations imply?

Fill in the blanks ((8)

24. Our greatest failure to implement renewable energy is our ___________. To encourage the development of renewable energy, the government could and should have (1)__________, (2)____________, and (3) ____________, thus providing incentive to develop these new resources. Unfortunately, the Bush administration

has not implemented such measures mostly because of __________, ___________, __________ and ___________.

H. I. Final31. About how many insect species are believed to exist in the Costa Rican rain forests?32. How many mammalian species make their homes in the CR rain forests?33. How many bat species?34. How many primate species?35. How many rodents? (1 pt each for 31 - 38)36. How many plant species?37. How many marine mammals?38. How many eukaryotic species have been identified and classified altogether on Earth?

H. I. Final39. Why are Costa Rica’s health stats above those of the United States in spite of the tremendously greater wealth of the U. S.? Please provide 5 tangible (including societal) reasons as discussed during Dr. Fred Gifford’s and Dr. Mario Tristan’s lectures. Hint: SICKO (5)

40. What are three very important bacterial infectious diseases in Costa Rica? (3)

H. I. Final

41. (8 pts) Please explain how aerosols such as CFCs and HCFCs cause destruction of the stratospheric ozone layer. Explain the time lapses for decay and the principle of the molecular mechanism involved.

H. I. Final Please translate into English (3 pts):Spanish

43 43, Pura Vida!

44, Lo siento.

45, Soy vegetariano.

Please translate into Spanish (3 pts): Please

46, Don’t worry!

47, Have a good time!

48, Congratulations!46

H. I. Final: extra credit; take home

42. Please list and explain the importance of 5 factors that throughout history, and including the present, have inhibited formation of a unified, international, human community that could help deal with the immense global environmental problems that face our species. (10)

Take Home; extra credit 25. List 25 ways YOU personally can become more environmentally friendly. (5 pts)Please then check those you actually have recently, or honestly plan to implement in the near future into your personal life style. (5 pts)

Essay type questions

26. According to OUTFOXED, what approaches has Fox “News” used to promote the Republican REACTIONARY agenda. Please list and describe at least 5 such approaches. (5)

27. Please describe an ORIGINAL approach (ONE THAT YOU HAVE NEVER HEARD PRESENTED BY SOMEONE ELSE) that you might implement so as to decrease your own contribution to global warming. (5)

28. What observations have you made since coming to Costa Rica that have had a lasting impact on your approach(s) to environmentalism, and how do you plan to implement the change(s) you propose? (5)

29. What observations have you made in Costa Rica that have changed your view of the world we live in? (5)

30. Based on what you have learned in Costa Rica over the past 5 weeks, WHAT POLICIES CHANGES ARE MOST URGENT FOR THE MAINTENANCE OF A FUNCTIONAL HUMAN SOCIETY? Please list five. (5)

H. I. Final Congratulations! You’re done with both finals! Pura Vida, let’s celebrate!

(But only after grading)

H. I. Final