Paul Magnano:Week 3 Individual Journal

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==Outline==
==Outline==
 +
===Experiment===
 +
*sacchromyces cerevisiae was grown in continuous culture, with varying ammonia input concentrations, while ammonia assiilation rates remained constant
 +
*ammonia is a preffered nitrogen source for s. cerevisiae, because it results in faster growth than other sources
 +
*in this study, cultures were grown with same flux (relationship b/w external ammonia concentration and rte of assimilation) but different inflow ammonia concentrations
 +
*Physiological parameters:
 +
**S. cerevisiae SU32 grown in continuous cultures with ammonia inflow concentrations ranging from 29 to 118mM
 +
**fixed glucose concentration of 100mM
 +
*Fig 1A
 +
**increase of ammonia concentration from 29 to 61mM resulted in increase of biomass from 4.9 to 8.2 g/liter
 +
**ammonia concentration above 61mM biomass remained at 8.2 g/liter
 +
**over trhe entire range of ammonia concentrations the ammonia flux into biomass was 1.1 mmol/gh
 +
*Fig 1B
 +
**input ammonia concentration above 44mM resulted in (c02 production/02 consumption) remained constant
 +
**with ammonia limitation (ammonia input below 44mM) c02 production and 02 consumption values differed
 +
**no changes in the residual glucose concentration were seen
 +
**no significant changes in carbon metabolism occured when the culture was switched from ammonia excess to ammonia limitation
 +
*Fig 1C
 +
**ammonia within the cells reacts with ketoglutarate to produce glutamate which is converted to glutamine
 +
**ketoglutarate concentration decreased from 10 to 5 umol/g when the ammonia concentration changed from limited to excess
 +
**glutamate concentration increased within the cell, linearly
 +
**increaing ammonia concentrations caused the concentrations of glutamate and glutamine within the cell to increase
 +
 +
===Northern Analyses===
 +
*RNA analyses were done to see if RNA levels of nitrogen regulating genes changed with increased ammonia concentrations
 +
*genes GDH1, GDH2,GLN1 were determined to study responses to ammonia levels
 +
*Fig 2
 +
**increasing ammonia levels resulted in GDH1 levels staying the same
 +
**ammonia concentrations of 29-44mM there was no GDH2, but with increase to 61mM GDH2 level increased
 +
**maximum GLN1 expression was observed at 61mM
 +
** overall it was seen that ammonia concentration both repressed GDH1 and caused the expression of GDH2
==Ten New Terms==
==Ten New Terms==

Revision as of 22:10, 30 January 2013

Contents

Outline

Experiment

  • sacchromyces cerevisiae was grown in continuous culture, with varying ammonia input concentrations, while ammonia assiilation rates remained constant
  • ammonia is a preffered nitrogen source for s. cerevisiae, because it results in faster growth than other sources
  • in this study, cultures were grown with same flux (relationship b/w external ammonia concentration and rte of assimilation) but different inflow ammonia concentrations
  • Physiological parameters:
    • S. cerevisiae SU32 grown in continuous cultures with ammonia inflow concentrations ranging from 29 to 118mM
    • fixed glucose concentration of 100mM
  • Fig 1A
    • increase of ammonia concentration from 29 to 61mM resulted in increase of biomass from 4.9 to 8.2 g/liter
    • ammonia concentration above 61mM biomass remained at 8.2 g/liter
    • over trhe entire range of ammonia concentrations the ammonia flux into biomass was 1.1 mmol/gh
  • Fig 1B
    • input ammonia concentration above 44mM resulted in (c02 production/02 consumption) remained constant
    • with ammonia limitation (ammonia input below 44mM) c02 production and 02 consumption values differed
    • no changes in the residual glucose concentration were seen
    • no significant changes in carbon metabolism occured when the culture was switched from ammonia excess to ammonia limitation
  • Fig 1C
    • ammonia within the cells reacts with ketoglutarate to produce glutamate which is converted to glutamine
    • ketoglutarate concentration decreased from 10 to 5 umol/g when the ammonia concentration changed from limited to excess
    • glutamate concentration increased within the cell, linearly
    • increaing ammonia concentrations caused the concentrations of glutamate and glutamine within the cell to increase

Northern Analyses

  • RNA analyses were done to see if RNA levels of nitrogen regulating genes changed with increased ammonia concentrations
  • genes GDH1, GDH2,GLN1 were determined to study responses to ammonia levels
  • Fig 2
    • increasing ammonia levels resulted in GDH1 levels staying the same
    • ammonia concentrations of 29-44mM there was no GDH2, but with increase to 61mM GDH2 level increased
    • maximum GLN1 expression was observed at 61mM
    • overall it was seen that ammonia concentration both repressed GDH1 and caused the expression of GDH2

Ten New Terms

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