Reserve dynamics & social interactions in feeding

Bas KooijmanDept theoretical biology

Vrije Universiteit AmsterdamBas@bio.vu.nl

http://www.bio.vu.nl/thb

Amsterdam2005/08/15

Evolution of DEB systems

Reserve dynamics

Polymerization inhibitionmaintenance growth

catabolism

Structural homeostasis

usualontogeny

V

E

Enzymes at interface that mobilize reserves don’t “observe” grain size or substrate conc.No dilution by growth

3/1interface EV

structure

rese

rve

Volume-surface interactions

inactive enzyme

active enzyme in binding phase

active enzyme in production phase

product

substrate

Cells can “know” their size from the rate at which concentrations of substrate & product change if transformation is by membrane-bound enzymes

Membrane-mediated transformation ratesin isomorphs decreasewith length because oftransportation distance

Protein synthesis 7.5

spec growth rate, h-1 scaled spec growth rate

RN

A/d

ry w

eigh

t, μg

.μg-1

scal

ed e

long

atio

n ra

te

Data from Koch 1970Data from Bremer & Dennis 1987

RNA = wRV MV + wRE ME

dry weight = wdV MV + wdE ME

: These gouramis are from the same nest, These gouramis are from the same nest, they have the same age and lived in the same tank they have the same age and lived in the same tankSocial interaction during feeding caused the huge size differenceSocial interaction during feeding caused the huge size differenceAge-based models for growth are bound to fail;Age-based models for growth are bound to fail; growth depends on food intake growth depends on food intake

No age, but No age, but size:size:

Trichopsis vittatus

Rules for feeding

Social interaction Feeding

time

time time

rese

rve

dens

ityre

serv

e de

nsity

leng

thle

ngth

time 1 ind

2 ind

determinexpectation