archaebacterial cell membranes have a different chemical structure from those
found in eukaryotes and eubacteria (Zillig et al. 1987).
While the framework in ordinary lipids is a fatty acid chain and glycerine esters,
in archaebacteria it is an ester bond with saturated isoprenoids. Thermophile and
methane bacteria cell membranes also contain a ring-shaped tetraether structure and
closed diether tail. Tetraether lipids have a single-layer rather than a bilayer
structure. The characteristic chemical structure of archaebacterial cell membrane
limits is believed to be a specific membrane structure that has evolved to respond to
extreme conditions (such as high temperatures, high pressures, and high saline
concentrations). Research to understand liquid crystal behavior and protein interactions is still lacking, however, and a physiochemical approach is needed.
In 1977, the Japanese researcher Kunidake and others found dialkyl ammonium
chloride (which has a simplified phospholipid chemical structure) formed a similar
bilayer structure to a biomembrane. This lipid was a purely synthetic compound
that is not present in any organism, and the synthesis led to a worldwide trend of
biomembrane engineering studies using synthesized bilayers. The model chosen by
chemists from among the different synthetic candidate bilayers was a compound
from the cholesterol family, a double chain lipid typically seen in animal and plant
cell membranes.
Fuhrhop et al. succeeded in synthesizing a ring-shaped lipid similar to those
found in archaebacterial cell membranes and successfully formed a single-molecule
membrane vesicle in water. Additional modeling resulted in synthesis of a
single-chain compound with two hydrophilic groups, resulting in formation of a
single-molecule membrane. While a phase transition is believed to exist at 40 °C in
black membranes produced with terpenoid lipids from archaebacterial, no clear
phase transition temperature was observed in the single-molecule membrane
produced by Fuhrhop et al. Phase transitions typically appear in single-chain
compounds, with transition temperatures depending on chemical structure, and in
particular on the structure of aromatic portions. It still appears rather premature to
confer synthetic molecular membrane research the status of biomembrane
engineering on a par with protein or gene engineering.
In contrast, it is not at all premature to draw inspiration from the various
archaebacteria that sustain life activities in extreme conditions, and to attempt to
develop new functional membrane and liquid crystal materials. With researchers in
synthetic molecular membranes and marine biotechnology currently joining forces,
the day when marine organism-derived liquid crystals are produced and put to use
may not be far away (Shimomura 1989).
8.3.4 Developing New High-Temperature Superconductors
with Alginic Acid
Humans have long fantasized about what might lie in unknown worlds across the
sea. The medieval Age of Navigation marked a new beginning in linking that land
to the Old World; after that, the world became one. Boats were companions in
8.3 Bio Materials
253
found in eukaryotes and eubacteria (Zillig et al. 1987).
While the framework in ordinary lipids is a fatty acid chain and glycerine esters,
in archaebacteria it is an ester bond with saturated isoprenoids. Thermophile and
methane bacteria cell membranes also contain a ring-shaped tetraether structure and
closed diether tail. Tetraether lipids have a single-layer rather than a bilayer
structure. The characteristic chemical structure of archaebacterial cell membrane
limits is believed to be a specific membrane structure that has evolved to respond to
extreme conditions (such as high temperatures, high pressures, and high saline
concentrations). Research to understand liquid crystal behavior and protein interactions is still lacking, however, and a physiochemical approach is needed.
In 1977, the Japanese researcher Kunidake and others found dialkyl ammonium
chloride (which has a simplified phospholipid chemical structure) formed a similar
bilayer structure to a biomembrane. This lipid was a purely synthetic compound
that is not present in any organism, and the synthesis led to a worldwide trend of
biomembrane engineering studies using synthesized bilayers. The model chosen by
chemists from among the different synthetic candidate bilayers was a compound
from the cholesterol family, a double chain lipid typically seen in animal and plant
cell membranes.
Fuhrhop et al. succeeded in synthesizing a ring-shaped lipid similar to those
found in archaebacterial cell membranes and successfully formed a single-molecule
membrane vesicle in water. Additional modeling resulted in synthesis of a
single-chain compound with two hydrophilic groups, resulting in formation of a
single-molecule membrane. While a phase transition is believed to exist at 40 °C in
black membranes produced with terpenoid lipids from archaebacterial, no clear
phase transition temperature was observed in the single-molecule membrane
produced by Fuhrhop et al. Phase transitions typically appear in single-chain
compounds, with transition temperatures depending on chemical structure, and in
particular on the structure of aromatic portions. It still appears rather premature to
confer synthetic molecular membrane research the status of biomembrane
engineering on a par with protein or gene engineering.
In contrast, it is not at all premature to draw inspiration from the various
archaebacteria that sustain life activities in extreme conditions, and to attempt to
develop new functional membrane and liquid crystal materials. With researchers in
synthetic molecular membranes and marine biotechnology currently joining forces,
the day when marine organism-derived liquid crystals are produced and put to use
may not be far away (Shimomura 1989).
8.3.4 Developing New High-Temperature Superconductors
with Alginic Acid
Humans have long fantasized about what might lie in unknown worlds across the
sea. The medieval Age of Navigation marked a new beginning in linking that land
to the Old World; after that, the world became one. Boats were companions in
8.3 Bio Materials
253