5 Δεκ 2012 (πριν από 4 χρόνια και 4 μήνες)

301 εμφανίσεις


Seaweed = macroal

Green: Chlorophyta

Red: Rhodophyta

Brown: Phaeophyta

Seaweed usage:

Food: as “vegetables” in many countries

Pharmaceuticals & Neutraceuticals

novel chemical compounds

Eg. Halogen
ted monoterpenes

Ochtodes secundiramea

Red alga Callophycus serratus

10 new molecular structures: potential to kill cancer cells, bacteria, HIV

Fertilizers: seaweed extracts, humic acids, kelp meals, amino acids, fulvic acid, compost

source (macro & micro
rients, plant growth hormones), eg.
ainly brown algae

contain several
polysaccharides: alginales

Bioremediation: heavy metal contamination such as Cu & Fe

toxic effects: generalized anaesthetic
effects on cell membrane, disruption of essential enzymes
, and displacement of essential ions. Eg.

Co and Cd uptake. Powder of green and red seaweed mixed with DDT
contaminated soil

80% toxic chemical disappeared in 6 weeks.

Hydrocolloids: agar, agarose, carrageenan, allginate

industries: fo
od, ph
armaceutical, cosmetic,
textile, photography, laboratorial usage
, etc.

Pigments: for industry

Ecology: supply of O2, primary producers

Traditional Chinese medicine: eg. Digenea simplex, Caloglossa leprieurii



: 46 genera, >

100 species

for food, medicine, fertilizers, raw material in industry:
phycocolloids, mannitol, iodine, etc.


Tissue & cell culture

Genetic manipulation

economic aspect

Plant propagation


bioprocess technology: production of h
igh value chemicals in pharmace
neutraceuticals, etc.

Micropropagation techniques: cultivation, secondary metabolites prod
uction, genetic improvement,
tainable development & utilization of seaweed

Clonal propagation & Selection of strains

otential of important seaweeds, eg. Chondrus, Gigartina, Gracilaria, Kappaphycus

Mass production, mariculture:

a. mass generation of planting material for tank
bubbling and field cultivation using fragments and cell
aggregates of apical meristem,

b. freeze
thawing of apical meristem tissues enabled the production of plantlets producing rhizoids: for
cultivation in

the sea.

Mass plantlets and tetraspores from fragments and cell aggregates of meristematic and
submeristematic tissue of Palmeria palmata.

Simple vegetative propagation of thallus segments (2

3 cm long) in laboratory culture

deals with
species non

sponsive to time and protoplast culture. Selection of elite germplasm is a continous
process and a substantial amount of harvest is utilized as seed material for subsequent cultivation.

Isolation of useful mutants for cultivation

successful as genetic variant cells in thallus

lead to
develop in vitro cell culture technology

Tissue Culture

Genetic engineering of crop plants

Micropropagation using tissue culture methods

large scale propagation of clones with superior traits

l suspension allow a very large number of cells to be screened simultaneously for a desired trait in a
reasonable time frame and reproducible manner.

Note: alteration of generations (haploid and diploid)

effective in genetic improvement. Haploid tissue
nable easy detection of mutants, subsequent chromosome doubling produces fertile individual

pure breeding lines for selection and hybridization.


Involve preparation of axenic explants and their cultures on solid agar medium enriched w
ith a range of

and micronutrients, vitamins, sugar, plant growth regulators (auxins & cytokinins).

eg. Photo

advantage: enbale of continous, steady and defined production of high yields
of quality products

Type of study: callus formati
on, morphogenesis, role of plant growth in morphogenesis, role of carbon
source on callus development & growth, clonal propagation, etc.

Protoplast Biotechnology

Cells or tissues with specific cell wall treated with lytic enzymes

total removal of their
rigid and
complex polysaccharide cell walls

Enzymatic methods: seaweed exhibit a variety & complexity in their cell wall composition

combination of specific enzymes are needed to digest the cell wall.

Protoplasts research: to date 89 species, green: cell
ulase or in combination with macerozyme, brown
and red: alginase and agarase/carrageenase and cellulase

Factors affecting

Enzyme constituents, concentrations, pH, osmotic conditions and ionic strength of protoplast isolation
medium, incubation
temperature, physiological state and age of donor plant, and protoplast culture
medium and its culture conditions.

Function: seed stock for cultivation of green seaweed, stock for seedling (micro thalli): Ulva,
Monostroma, seeding and regeneration in laboa
ratory: Monostroma, Porphyra

Physiological studies: mechanism of inorganic carbon uptake in Chondrus crispus, Ulva rigida, Gracilaria
, O2 evolution rate to evaluate whether the isolated protoplasts are in the same
physiological state as cel
ls in an intact plant

Fusing protoplasts of different origins

produce novel somatic hybrids

study somatic cell genetics,
eg. Fusion of zoospores of Enteromorpha and Ulvaria

regeneration of intraspecific
parasexual hybrids

Genetic Transformation

Transient expression of the bacterial beta
glucoronidase gene (gus) in the carrageenan producing
red alga Kappaphycus alvarezii

Expressed sequence Tags (ESTs) from protoplasts and thalli

to identify the genes involved in cell wall
regeneration and stress

responses in Chondrus crispus and Laminaria digitata.

Method: using cDNA sequence

5 catagories:

a. those identical to a portion of a known gene

b. those with sequence similarity to a known gene

c. those which do not show sequence similarity but with stru
ctural similarity to one or more known

d. those which do not match anything in the database

e. those that can be deemed useless as they are either devoid or meaningful sequences or have
matched sequences of contaminating organisms

promoter selec
tion: 2 promoters have been used most often

1. NOS (nopaline synthase) from A. tumefaciens T

2. 35S from cauliflower mosaic virus (CaMV)

Promoter selection

efficiency of expression of foreign genes in transformants

Table 1. The timeline of seaweed r


Activity/Research Highlights


Discovery of hydrocolloids from seaweed, seaweed biology, research on seaweed as


First International Seaweed Symposium in Scotland



Taxonomic classificaion, biogeography and
ecophysiology of seaweeds


early 1990s

Mutant studies, seaweed cultivation and biotechnology, properties of hydrocolloids and
their applications in industries, drug discovery and bioactive compounds from seaweeds,
classical genetics

Mid 1990s

tic transformation and tissue culture, molecular phylogenetics, small
scale gene
cloning and characterization


Introduction of EST approach in large
scale study on molecular genetics


Search of a model plant for large
scale genomic study, shi
ft to multi
disciplinary research

Source: Chan
et al
. 2005(?)