Kasey E. O'Connor Week 11 Journal

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Journal Club Assignment



  1. In vivo - within a living organism [1]
  2. Diurnal - occurring during the day [2]
  3. Mannoproteins - highly antigenic yeast cell wall proteins with large numbers of mannose groups attached [3]
  4. Cuvette - a transparent container with precisely-measured dimensions for holding liquid samples to be put into a spectrophotometer [4]
  5. Transcriptome - the complement of mature messenger RNAs produced in a given cell in a given moment of its life [|5]
  6. Prototropic - strains that have the same nutritional requirements as the wild-type strain [6]
  7. sphingolipids - structural lipid of which the parent structure is sphingosine rather than glycerol synthesised in the Golgi complex [7]
  8. Orthologues - genes that can be found in two or more different species that can be traced back to the same common ancestor [8]
  9. Oleate - A salt of oleic acid, some oleates, as the oleate of mercury, are used in medicine by way of inunction [9]
  10. Assay - The determination of the amount of a particular constituent of a mixture or of the biological or pharmacological potency of a drug [10]



  • Seasonal and daily temperature changes are inevitable in the lives of microorganisms living in natural environments.
    • There are many different cellular responses among yeast cells.
    • Temperatures below the optimal environment (25-35 degrees) affect enzyme kinetics, cellular growth, respiration, and lipid composition of membranes.
  • Sudden exposure to cold triggers stress response while longer exposure leads to acclimation and eventually adaptation
  • Two distinct phases of cold shock response have been noticed through other studies
    • Early Cold Response (ECR) occurs within the first 12 hours
    • Late Cold Response (LCR) occurs after 12 hours of exposure
  • Genes associated with cold shock have been consistently observed
    • TPS1, TPS2, HSP12, HSP26, HSP42, HSP104, YRO2, and SSE2
  • Already published data about low-temperature transcriptomes have shown inconsistencies among expressed genes
  • Most published low-temperature studies on yeast have been performed in batch cultures
    • This method is poorly adapted for the study of prolonged cold exposure because the growth rate is strongly affected by the temperature
  • Chemostat cultures enable control of the growth rate
    • They provide a reproducible environment for study on gene expression in fully controlled cultures
  • The goal of the study is to investigate S. cerevisiae at suboptimal temperatures and look at the entire genome transcriptional regulation
    • Grown at 12 to 30 degrees Celsius
    • Grown in anaerobic conditions at a fixed growth rate of 0.03 h-1
    • The transcription was analyzed in both glucose and ammonium limited chemostat
    • The results of this analysis were compared to previous studies in the batch cultures

What is the main result presented in this paper? What is the importance or significance of this work? How did they treat the cells (what experiment were they doing?) What strain(s) of yeast did they use? Was the strain haploid or diploid? What media did they grow them in? Under what conditions and temperatures? What controls did they use? How many replicates did they perform per condition? What mathematical/statistical method did they use to analyze the data? What transcription factors did they talk about? Briefly state the result shown in each of the figures and tables.

Figure Presentation

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