''Leucosporidium frigidum'' is a
species of
yeast that belongs to the
genus of
fungi ''
Leucosporidium
''Leucosporidium'' is a genus of fungi found in the family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). T ...
'', and the
family Leucosporidiaceae
The Leucosporidiales are an order of fungi in the Microbotryomycetes class of the Basidiomycota. The order contains a single family, the Leucosporidiaceae, which in turn contains three genera and eight species. The order was circumscribed in 2003 ...
.
Growth temperature
''Leucosporidium frigidum'', together with ''
Leucosporidium gelidum'', and ''
Leucosporidium nivalis'' are classified as obligate
psychrophiles since they grow well at subzero temperatures and are unable to grow at temperatures above . ''Leucosporidiaceae frigidum'' grows at .
Rapid growth of Leucosporidiaceae occurs at , and slight increase in temperature results in growth decrease.
Its maximum growth temperature is when
glucose is used as
carbon source and when
ethanol is used.
The growth rate of ''Leucosporidium frigidum'' on glucose as
substrate
Substrate may refer to:
Physical layers
*Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached
** Substrate (locomotion), the surface over which an organism lo ...
for a given temperature is higher than that on ethanol. The cell yield of Leucosporidium is maximum at subzero temperatures.
Membrane lipid composition
There is a positive correlation between the growth temperature and the degree of
fatty-acid unsaturation of the cell
lipids of ''Leucosporidium frigidum''.
The variation in the degree of fatty acid unsaturation of the yeast indicates its ability to alter the
cellular component is fundamental to adaptation to environmental changes. The extent to such ability determines the growth temperature limits of ''Leucosporidium frigidum''. The lower limit is the point at which its
membrane lipids solidify and the upper limit is the point at which its membrane lipids melt.
Cytochrome concentration
''Leucosporidium frigidum'' shows
absorption bands at room temperature characteristic of
cytochromes ''aa3'', ''b'' and ''c''.
The concentration to the cytochromes in ''Leucosporidiaceae frigidum'' is negatively related to its membrane-lipid unsaturation rate. At the maximum growth temperatures when the degree of lipid unsaturation of the cell membrane is high, the final cell yield is less than at lower temperatures when membrane-lipid unsaturation rate is low. This indicates
glucose repression
Glucose is a simple sugar with the molecular formula . Glucose is overall the most abundant monosaccharide, a subcategory of carbohydrates. Glucose is mainly made by plants and most algae during photosynthesis from water and carbon dioxide, using ...
of cytochrome
synthesis
Synthesis or synthesize may refer to:
Science Chemistry and biochemistry
*Chemical synthesis, the execution of chemical reactions to form a more complex molecule from chemical precursors
** Organic synthesis, the chemical synthesis of organ ...
occurs at high degree of lipid unsaturation. However, a high concentration of cytochrome ''c'' is observed at the maximum growth temperatures of ''Leucosporidium frigidum''. This phenomenon may be an attempt by the cells to compensate for the decrease in cytochrome ''a+a3'' by involving alternative pathways of
electron transport.
Functions of cellular membranes
The positive correlation relationship between the growth temperature of ''Leucosporidiaceae frigidum'' and the membrane-lipid unsaturation rate, and the negative relationship between the membrane-lipid unsaturation rate and cytochrome concentration in cells indicate the
membrane structure
Membrane structures are spatial structures made out of tensioned membranes. The structural use of membranes can be divided into pneumatic structures, tensile membrane structures, and cable domes. In these three kinds of structure, membranes work ...
and composition are significant to temperature adaptation in ''Leucosposidiaceae frigidum''. Manipulation of the fatty-acid unsaturation index allows ''Leucosposidiaceae frigidum'' to alter its membrane fluidity, and function with changing temperatures.
References
{{Taxonbar, from=Q16754393
Yeasts
Fungi described in 1969