134
Bacterial Cellulose
The.rate.and.direction.of.the.movement.correspond.to.those.of.the.fiber.
production..The.fibers.were.reported.to.be.produced.at.a.rate.of.2.μm/min.
at.25°C.(Brown.et.al..1976)..However,.G. xylinus.produced.the.fiber.faster.on.
NOC.templates,.at.a.rate.of.4.5.μm/min.at.24°C..This.gap.is.thought.to.be.due.
to.the.strength.of.the.interaction.between.the.biosynthesized.fiber.and.the.
NOC.surface..It.is.also.indicated.that.the.NOC.surface.promoted.the.secretion.rate.of.the.fibers.
The.optimal.condition.on.the.templates.containing.the.additives.for.the.culture.medium.was.studied.in.order.to.understand.the.factors.influencing.the.
rate.of.movement.of.G. xylinus.accompanied.with.the.secretion.of.a.nanofiber.
(Tomita.and.Kondo.2009)..The.template.having.a.molecular.orientation.at.a.
higher.draw.ratio.was.more.effective.at.enhancing.the.moving.rate..Further,.
the.moving.rate.may.depend.on.the.constituents.of.the.template..The.additive,.
brils.from.self-assembling,.which.resulted.in.an.increase.in.the.rate.of.movement. on. the. agar. substrate.. In. fact,. the. Hestrin–Schramm. (1954). medium.
containing.1%.CMC.with.a.low.DP.enhanced.the.moving.rate.of.the.bacterium.cultured.on.the.template.without.orientation..Furthermore,.on.an.NOC.
template,.the.Hestrin–Schramm.medium.containing.1%.CMC.with.a.high.DP.
was.more.effective.at.increasing.in.the.moving.rate..Presumably.alignment.
of.the.CMC.molecules.onto.the.oriented.cellulose.molecules.in.the.NOC.by.
a.strong.interaction.caused.the.increase.in.the.moving.rate..From.the.results,.
the.conditions.for.increasing.the.moving.rate.are.proposed.to.employ.a.flat.
drawn.template.with.an.orientation.that.can.engage.with.other.materials.by.a.
strong.interaction..Further,.supplying.an.additive.to.the.medium,.which.prevents.self-assembly.of.secreted.cellulose.microfibrils,.is.also.effective..Thus.
understanding.how.to.prevent.self-assembly.of.the.secreted.microfibrils.on.
the.oriented.templates.could.be.the.easiest.way.to.find.an.optimal.condition.
for.enhancing.the.fiber.production..More.importantly,.the.regulated.movement.of.the.bacteria.due.to.the.ordered.surface.of.the.NOC.may.trigger.the.
development.of.a.3D.structure.of.hierarchical.architecture.from.the.nano.to.
the.micro.levels..Therefore,.we.could.regulate.the.3D.architecture.of.materials.
using.nanofiber.secreted.by.G. xylinus.as.a.building.block.
Regulated Patterns of Bacterial Movements Based on
Their Secreted Cellulose Nanofibers Interacting
Interfacially with Ordered Chitin Templates
When. active. G. xylinus. cells. are. transferred. to. the. nematic. ordered. chitin.
surface,.they.synthesize.cellulose.nanofibers.(i.e.,.cellulose.ribbons).that.are.
not.parallel.to.the.molecular.orientation.of.the.substrate,.unlike.the.secreted.