Amit Frishberg

Lab: Dr. Iftach Nachman

Few facts about yeasts

• Can appear in haploid or diploid forms.

• Can grow on different types of carbon

mediums.

• Can use respiration or fermentation as

their preferred carbon consuming method.

• Have a relatively high reproduction rate.

Respiration / Fermentation

Respiration

Carbon

Glycolysis

Aerobic conditions

Fermentation

Carbon

Glycolysis

Anaerobic conditions

Ethanol

The selected method depends on the carbon medium which the yeasts use.

Can be reused by the yeasts

Experiments in the lab

• Researching the differences in the nutrient

sensing mechanism in different types of

wild type yeasts.

• Finding the genotypic differences in those

types that cause to the diverse in the

mechanism.

My project questions

• Is there a difference in the growth rate of

different types of yeasts (S. cerevisiae)?

• What are the reasons for those differences if

they’re exist?

• How do different carbon mediums effect the

growth rate of different types of yeasts?

So where did we start?

55gift from Barak CohenYPS606Oak Tree

56gift from Barak CohenYPS623Oak Tree

57gift from Barak CohenBW-1Oak Tree

58gift from Barak CohenCP-1Oak Tree

59gift from Barak CohenIN-1Oak Tree

60gift from Barak CohenT7Oak Tree

61gift from Barak CohenTN-1Oak Tree

62gift from Barak CohenNC-02Oak Tree

63gift from Barak CohenIL-01Oak Tree

64gift from Kruglyak's labCLIB192 Baker France

65gift from Kruglyak's labCLIB274_1

66gift from Kruglyak's labCLIB326_1

67gift from Kruglyak's labCLIB219_2b

68gift from Kruglyak's labCLIB272_2

69gift from Kruglyak's labCLIB382 Beer Ireland

70gift from Kruglyak's labYJM145 Clinical. AIDS patient Unites States

71gift from Kruglyak's labYJM280 Clinical. peritoneal fluid Unites States

72gift from Kruglyak's labYJM320b Clinical. blood Unites States

73gift from Kruglyak's labYJM326 Clinical. unknown Unites States

74gift from Kruglyak's labYJM413 Clinical. blood Unites States

75gift from Kruglyak's labYJM421 Clinical. ascites fluid Unites States

76gift from Kruglyak's labYJM428 Clinical. paracenteis fluid Unites States

34gift from Barak Cohen

UCD 51Vineyard

35

gift from Barak Cohen

UCD 175Vineyard

36

gift from Barak Cohen

UCD 522Vineyard

37

gift from Barak Cohen

UCD 529Vineyard

38

gift from Barak Cohen

UCD 762Vineyard

39

gift from Barak Cohen

UCD 765Vineyard

40

gift from Barak Cohen

UCD 781Vineyard

41

gift from Barak Cohen

UCD 820Vineyard

42

gift from Barak Cohen

UCD 2120Vineyard

43gift from Barak CohenM5Vineyard

44gift from Barak CohenM7Vineyard

45gift from Barak CohenM13Vineyard

46gift from Barak CohenM15Vineyard

47gift from Barak CohenM22Vineyard

48gift from Barak CohenM29Vineyard

49gift from Barak CohenM30Vineyard

50gift from Barak CohenM33Vineyard

51gift from Barak CohenM34Vineyard

52YIN1-Msn2-482yIN1 transformed with PCR product of msn2 and pSR482

53YIN1-Msn4-482yIN1 transformed with PCR product of msn4 and pSR482

54YIN1-Rim15-482

yIN1 transformed with PCR product of rim15 and pSR482

And many more…

We had more than 100 species to begin with:

Problems with the system

• The experiment was too complicated (too many

species) - it would have take us too much time.

• We wanted to focus on the most important

species in order to study them better.

• We didn’t know which medium to use for most of

our species.

Narrowing the species

• We selected 20 types of yeasts:

– Wine yeasts - 9 types (34-42).

– Oak yeasts – 9 types (55-63).

– Sk1 , sigma (lab strains)

• We wanted to compare between the well

researched wine yeasts and the oak yeasts.

Checking OD for growth rate

1. Setting the basic OD of all species to

the same level.

2. Monitoring the change in OD over time.

3. Managing the result (using excel and

mathlab) to build growth charts.

Work method

20 species in test tubes – non saturated

Raising over night (O.N)

20 species in test tubes – saturated

Dilution to a 96 cells plate

Putting inside the robot

Structure of the 96 cells plate

123456789101112

 B 57 616335SK139  A

 B555759616335SK139  B

 B555759616335SK139  C

 B554259414141sigmasigma  D

 B56424262373737sigma  E

 B5658606234363840  F

 B5658606234363840  G

 B 5860 34363840  H

Using the robot

• The robot contains 3 main parts:

1. The incubator.

2. The shaker.

3. The OD reader.

30 min incubation

1 min shake

OD check

תמונה של

הרובוט

Growth rate on Glucose rich medium (YPD)

• We assumed that both types of

yeasts will use this medium and grow

fast on it.

• We put the 96 cells plate for 24 hours

in the robot.

ResultsOD as a function of time

ResultslogOD as a function

of time

ResultsOD mean as a function

of time

ResultslogOD mean as a function

of time

Conclusions

• Both types of yeasts got to the same saturation levels.

• Both types of yeasts used fermentation as their

preferred carbon consuming method.

• Oak yeasts got out of lag phase faster than wine

yeasts.

• Oak yeasts had a faster growth rate than wine yeasts.

Growth rate on Acetate rich medium (YPA)

• We assumed that both types of yeasts will use

this medium and grow on it.

• We assumed that oak yeasts will grow faster on

it than wine yeasts.

• We put the 96 cells plate for 72 hours in the

robot.

ResultsOD as a function of time

ResultslogOD as a function

of time

ResultsOD mean as a function

of time

ResultslogOD mean as a function

of time

Conclusions

• The growth rate of both types of yeasts was much slower

than on YPD.

• Both types of yeasts used fermentation as their preferred

carbon consuming method.

• Both types of yeasts got almost to the same saturation

levels.

• Oak yeasts got out of lag phase faster than wine yeasts.

• Oak yeasts had a faster growth rate than wine yeasts.

Does cell size take part in those results?

Both types of yeasts has almost the same cell size

We observed the two types of yeasts with an electron microscope:

Oak yeastsWine yeasts

The clumpiness factor

• Both type of yeasts were capable of creating

clumps.

• The wine yeasts had a much higher clumpiness

ratio than the oak yeasts.

Oak yeasts

Wine yeasts

Future experiment

• Studying the biological mechanism that

provides the oak yeasts a faster growth

rate on those mediums.

• Continue the comparison between wine

and oak yeasts to different types of yeasts.

Thanks

Dr. Iftach Nachman

Dr. Yifat Goldshmidt