Diffrent algal gropus, Cyanobacteria, chlorophyta, Xanthophyta

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Dinoflagellates

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General Characteristics
 Most species are marine.
 Most dinoflagellates are autotrophic, but
saprophytic, symbiotic and holozoic are
found.
 are unicellular, motile and flagellates
- The presence of chlorophyll-a, and
carotenoids ( peridin and neoperidinin)
 The storage product is starch in freshwater
forms and oil in marine species.

3. Structure of dinoflagellate cell
 It consists of epicone and
hypocone.
 The epicone and hypocone are
divided into a number of
thecal plates in armored
species only
 - Dinoflagellates have two
unequal flagella: transverse
flagellum that fits into the
transverse groove of the body (
girdle or cingulum);
 and a longitudinal flagellum
that projects from the
longitudinal groove (sulcus).
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 The dinoflagellate nucleus is unlike that of either
prokaryotic or eukaryotic and are mesokaryotic.
Prokaryotic
 - the condensed state of the chromosomes, even
during interphase.
- close association of genetic material with nuclear
envelope.
- - the absence of histone (basic protein).
- Eukaryotic
- - the presence of the nucleolus, nuclear envelope,
and the DNA sequence.

5.  Asexual rep: aplanospores and
cysts.
 Cysts have a wall mor resistant
to acid and alkali (fossils of
Dinoflagellates are cysts)
 -there are two types of cysts:,
similar to the vegetative cells as
in peridinium;
 and different from vegetative
cells and covered with tubular
projections - hystrichospheres) as
in Gonyaulax.
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6.  Sexual reproduction
 is not very common in dinoflagellates and only
known in a few species. isogamous or
anisogamous
 Most dinoflagellates have haplontic life cycle.
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Dinoflagellate life cycle

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Medical and ecological significance of
dinofalgellates
 Dinofalgellates cause “red tides” that often kill
fish and/or shellfish
 Dinofalgellate toxins accumulate in shellfish or
fish, and when these are eaten by humans they
cause poisoning like paralytic shellfish poisoning
(PSP), neurotoxic shellfish poisoning (NSP),
diarrheic shellfish poisoning (DSP) and
ciguatera.
 They are marine primary producers.
 Dinoflagellates have a pivotal role in the biology
of reef-building corals.


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Phaeophyta- Brown algae
 They are macroalgae found almost exclusively in
the marine habitat
 Contain Chl. A and fucoxanthin (brown) pigments
 Cell wall - cellulose and alginic acid
 Storage material: Laminarin
 The chloroplasts have two membranes of
chloroplast E.R continuous with the outer
membrane of the nuclear envelope

10.  Order Fucales
 Fucus & Sargassum
 Habit: Parenchymatous
Thallus: holdfast, stipe, blade,
airbladders, fronds,
receptacles
 Veget. rep.: Fragmentation
 Asexual rep.: absent
 Sexual rep. Oogamy
 Gametes are formed in
conceptacles located on the
receptacles (the reproductive
branches).
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11.  Life cycle: Diplontic
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12. Medical and ecological significance
of brown algae
 food for herbivorous fish and shellfish, and human
 Algin -a stabilizer and emulsifier in making dairy
products. , a thickener in pharmaceutical and chemical
industries, such as making toothpaste, shampoo.
 In textiles, alginates are used to thicken fiber-reactive
dye pastes
 Alginates - dental impressions of teeth.
 The seaweed can also be used for sushi.
 Fucoidans which inhibits lipid accumulation and
therefore can be useful for the prevention or treatment
of obesity due to its stimulatory lipolysis.
 Fucoidans from the brown alga Sargassum exhibits
anticancer activity
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Rhodophyta- Red algae
 Most red algae are marine macroalgae
 No flgellated forms
 Main pigments: Chl.a and Phycoerythrin (red)
 Storage material: Floridian starch
 Cell wall: cellulose,
 Like Cyanobacteria, chloroplast with one
thylakoid per band (unstacked thyllakoids) and
no chloroplast E.R.

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Polysiphonia
 Habit: Branched siphonaceous
 Thallus: rhizoids, fine branched filaments or
siphons

15.  Asexual rep: Tetraspores
 Sexual Rep: oogamy and formation of carpospores.
 Life cycle in Polysiphonia has three stages (triphasic
 isomorphic gametophyte (1n) and sporophyte (2N)
generations are separated by the carposporophyte
(2N).
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17. Medical and ecological significance of red
algae
Primary producers, used as food and medicines for
centuries
They produce agar, carrageenans, and alginates
used in numerous food, pharmaceutical, cosmetic, and
industrial applications.
 Carrageenan is used for stabilizing chocolate, milk,
egg nog, ice cream, sherbets, instant puddings,
frostings, creamed soups, etc.
 Agar is used in bacteriology and mycology as a
stiffening agent in growth media.
 Agar is used as a stabilizer for emulsions, and as a
constituent of cosmetic skin preparations, ointments,
and lotions..
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18. A very important group of red algae is the
coralline algae, are used in bone-replacement
therapies.
Coralline algae were used in ancient times as
vermifuges (antiparasitic)
sulfated polysaccharides inhibit both the DNA
and RNA of viral infections and may operate
both outside and within our infected cells.
Red algae contain bromophenols, which have
Cellular Antioxidant Activity.
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