Sonia 

G

good day, what do you mean?, how to measure growth rate or if there is any data available to compare between vibrios??.

Regards

Pablo

Sonia, I don't know about existing data on Vibrio.  However, with respect to growth rates, the answer depends on how you are measuring the growth rate - in batch culture or a chemostat.  But the units for the specific growth rate are in hr^-1, or per hour (or per unit time).

The only real way to get the specific growth rate is to use a chemostat, since you want that rate to represent the true exponential growth rate of the bacteria.  This is very difficult to achieve in batch cultures, since it is only in exponential state for a short time, making it necessary to make many measurements over the course of batch cultures to determine it.  In a chemostat, one is able to achieve steady state exponential growth and the specific growth rate can be measured more accurately.

Basically, the relationship  follows an Ahrenius equation, Xt = Xo(e^rt), where Xt = the cell density at time t, Xo = the cell density at time 0, and r = the growth rate.  If you linearize the equation by taking the natural log of both sides, you end up with 

lnXt - lnXo=rt

which, as you can work out, gives you a hr^-1 unit for r, the specific growth rate. 

Which is very useful, since you can come up with values for r with only a couple of measurements of cell density in an experiment, making comparisons between experiments with different parameters pretty straightforward.  

Note that this is not quite the same as the time of doubling for cells, because in a chemostat, not all the cells have the chance to reproduce before they are washed out.  Without deriving it all here, the relationship between the specific growth rate and the time of doubling, k, is

r = k(ln2) = 0.693(k)

Hope this helps.  As usual, a good microbiology book has all of this in it.

Mark

http://miller-lab.net/MillerLab/protocols/general-bacteriology/calculating-growth-rate/ 

you can find the answer form this link

Hi there,

Mark, the exponential growth law you give Xt = Xo(e^rt) has nothing to do with the Arrhenius equation except they are both exponential!!!

As a reminder Arrhenius equation makes the link between a rate constant k and the temperature T (k = A*e(-E/RT)) (which is not kinetics) whereas the growth rate equation gives the relation between biomass and the culture time (basically it's kinetics).

Dominique, I stand corrected.  Thanks for the note on the difference for the two equations.

Mark

Hi: This is some usefule referances for you:

http://booksite.elsevier.com/samplechapters/9780123705198/Sample_Chapters/04~Chapter_3.pdf

http://www.lamission.edu/lifesciences/lecturenote/mic20/Chap06Growth.pdf

https://math.la.asu.edu/~halsmith/bacteriagrow.pdf

http://www.umsl.edu/~microbes/introductiontobacteria.pdf

Thanks to all!! It was very usefull for my data analysis.

Pablo; I´m looking for any data available for compare among vibrios strains.

123

Hi Sonia

See the attachment 1

https://miller-lab.net/MillerLab/protocols/general-bacteriology/calculating-growth-rate/

2

http://microbiology.ukzn.ac.za/Libraries/MICR304/MEASUREMENT_AND_KINETICS_OF_MICROBIAL_GROWTH.sflb.ashx

3

http://www.microbiologyresearch.org/docserver/fulltext/micro/21/1/mic-21-1-40.pdf?expires=1491499236&id=id&accname=guest&checksum=8524C627826C773361E659BA97B3AD7F

4

http://booksite.elsevier.com/samplechapters/9780123705198/Sample_Chapters/04~Chapter_3.pdf

5

https://math.la.asu.edu/~halsmith/bacteriagrow.pdf

6

https://bionumbers.hms.harvard.edu/bionumber.aspx?id=111284

7

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1449012/

8

https://vlab.amrita.edu/?sub=3&brch=73&sim=1105&cnt=1

9

https://de.mathworks.com/matlabcentral/newsreader/view_thread/317961

10

https://books.google.com/books?isbn=0306423464

11

http://biology.stackexchange.com/questions/20364/calculation-of-the-bacterial-growth-rate-from-a-spectrophotomer-growth-curve

12

http://www.cee.mtu.edu/~nurban/classes/CE3501/Fall05/Assignments/EnvBiolPS1_05Sol.pdf

13

http://www.stewartcalculus.com/data/BIOCALCULUS/BB/BB_Chapter2/E2.2.1/Monod%201949.pdf

14

https://www.chem.ucla.edu/dept/Faculty/merchant/pdf/microbial.pdf

15

https://w3.ualg.pt/~hgalvao/mpob/methodsmicrobiolvol30_1-2/sdarticle_013.pdf

16

https://dspace.lboro.ac.uk/dspace-jspui/bitstream/2134/3478/1/Growth%20rate%20estimation%20final.pdf

Good luck

units of time -1 : sample 1 h -1, 20 min-1, specific growth rate.

It is expressed as say mg/l/h or ppm per hour (time).

Please express the time and concentration which is required by the study.

It is basically concentration per unit time.

Dear Ishan

mg/l/h express productivity units, specific growth rate units are d-1, h-1 usually, you should states any methodology for define your growth curve, ie, cell number or density, dry weight or wet weight. Specific product formation rate and specific consumption substrate rate units are d-1 or h-1

Dear Facundo,

Per unit time is the unit for maximum specific growth rate i.e. umax.

Please support your opinion by some authentic source.