Eukaryotic microorganisms
and viruses
-Algae-
Katarzyna A. Palińska
Geomicrobiology,
ICBM,
CvO University of Oldenburg, Germany
Email: [email protected]
Brief history of photosynthetic
organisms on earth…
3.45 bya =
Cyanobacteria appear and introduce photosynthesis
1.5 bya =
first Eukaryotes appeared
400-500 mya = plants on land
Botany = study of plants
Phycology = study of algae (Latin)
Algology = less correct (close to the study of pain)
(Greek)
alga (singular)
algae (plural)
algal (adj.)
“algaes” (wrong!)
Defining characteristics of
algae
•Photosynthesis (photoautotropic, usually), using Chl a as
primary pigment
BUT: Limited cellular differentiation compared to
terrestrial plants
•no “real” vascular system
•sex organs unicellular or if multicellular -> “naked”
“naked” reproductive structures (no sterile layer of
cells surrounding sex organs)
•In some cases: all cells capable of reproduction
•MUCH greater diversity of photosynthetic pigments
What are algae?
• several groups of relatively simple living aquatic
organisms that capture light energy through
photosynthesis, using it to convert inorganic substances
into organic matter.
• polyphyletic group = different ancestors, different
evolutionary histories
•algae group includes prokaryotes (cyanobacteria) AND
eukaryotes (green, brown, red algae) – traditional
approach
• green, red, and brown algae are now thought to be in
different kingdoms (some biologists place greens in
Plantae)
Separated from animals
• Algae produce spores (asexual reproductive
cells) as well as gametes (sexual cells).
• Animals produce only gametes.
Hierarchical system of
classification…
Level:
Kingdom
Phylum/Division
Class
Order
Family
Genus
Species
suffix:
-phyta
-phyceae
-ales
-aceae
example:
Protista
Chlorophyta
Chlorophyceae
Ulotrichales
Ulvaceae
Ulva
fenestrata
Algal taxonomy
• King Phillip Came Over For Good Spaghetti
• Keep Dishes Clean Or Family Gets Sick
Taxonomy/systematics
constantly under
revision
- depending on whom you ask, between 50,000 and
10 million different algal spp!
How to define species???
- Biological species concept?
-Morphology?
-Genetics?
ts
als
im
An
fungi
3
pl
an
1
2
EUKARYOTES
“Crown species”
Protoctista
4
Monera
5
Five Kingdoms
PROKARYOTES
5
1
4
2
3
The Cell
Prokaryotic
Eukaryotic
Autofluorescence of algal and
cyanobacterial cells
Classification of phototrophic organisms
in terms of energy and carbon sources.
Types of algal body
unicellular
foliar
colonial
tubular
Bladelike, kelp
filamentous
Leafy
axis
Bold, HC and Wynne, MJ. Introduction to the algae, Prentice-Hall, Inc.New Jersey.
Sexual reproduction of
algae and nonalgal plants
Uniting
gamets of a
unicellular
alga
Multicellular
Archegonium Antheridium
Unicellular
gametangia gametangium (liverwort)
(liverwort)
of a
filamentous
alga
Bold, HC and Wynne, MJ. Introduction to the algae, Prentice-Hall, Inc.New Jersey.
Sexual
reproduction
Isogamy (zygote)
Oogamy (oospore)
Conjugation (zygospore)
Algal life
cycles
Bold, HC and Wynne, MJ. Introduction to the algae, Prentice-Hall, Inc.New Jersey.
Cyanobacteria
S external layer (slime)
OM outer memebrane
PL peptidoglycan layer
CM cytoplasmic membrane
CW cell wall
CY cytoplasma
E cell envelope
GV gas vesicle
N nucleoplasmic region
C carboxysome
PP polyphosphate granule
CP cyanophycin granule
GG glycogen granules
TH thylakoid
PB phycobilisome
From: Margulis, L & Schwartz, K.V. 1998 Five Kingdoms. Freeman, NY
Staley, J. T. et al 1989 Bergey’s manual of Systematic bacteriology. William & Wilkins, Baltimore
Cyanobacteria - Form
diversity
‹
0.5 - 60 µm
‹
Pigments
Cayanobacterial Taxonomy:
Rippka et al. 1979
Group I
Unicellular
Gloeothece PCC 6909
Binary fission in one
plane
Binary fission in
2-3 planes
Slime
Thylakoids
Scheath
+
Chroococcus PCC 9340
Gloeobacter
+
+
+
Gloeothece
Gloeocapsa
+
-
-
Synechococcus
Cyanothece PCC 7418
Synechocystis
+
+
Chamaesiphon
Merismopedia punctata
Group II
Unicellular, division in multiple planes
Motile
baeocytes
Unmotile
baeocytes
Stanieria
Xenococcus
Motile baeocytes,
Pseudofilaments
Pleurocapsa
Stanieria PCC 7301
Pleurocapsa
Group III
Filamentous, division in one plane
Motile, sheath absent or very thin,
Spirulina
Spirulina PCC 9445
Motile, sheath absent or very thin
Oscillatoria
Oscillatoria sp.
Non motile, very thick sheath
LPP A
Lyngbya sp.
Motile, sheath absent; constrictions; polar gas vesicles
Pseudanabaena
Pseudanabaena PCC9716
Motile and no-motile, with or without sheath
LPP B
Phormidium sp.
Group IV
Filamentous, with heterocysts and division in one
plane
Hormogonia
-
Heterocysts and
Akinets
Cell form
Typical genera
Heterocysts
intercalary or terminal,
Spherical or
oval
Anabaena
Akineten changeable
cylindrical
Nodularia
Heterocysts terminal,
Akineten next to
Isodiametric or
cylindrical
Cylindrospermum
heterocysts
+
Heterocysts terminal, Spherical or
Akineten several in the oval
Nostoc
row
Heterocysts
cylindrical
Scytonema
Heterocysts basal
cylindrical
Calothrix
intercalary
Group V
Filamentous, with heterocysts, division in more than one
plane
Reproduction
Heterocysts
Adult-stage
Through
breakage of the
trichome,
hormogonia or
akinets
Terminal or
intercalary
Breakage of the
trichome results
in formation of
Gloeocapsa-like
aggregates,
containing
heterocysts, from
which later
hormogonia are
created
Intercalary
Trichoms with
lateral branching
from which later
hormogonia are
created
Typical genera
Chlorogloeopsis
Stigonema
Fischerella
Prochlorales
(pro-primitive, chloros-grün)
chlorophyll a und b, Phycobiliproteins
Prochloron (Lewin 1977)
Prochlorothrix (Burger-Wiersma et al. 1986)
Prochlorococcus (Chisholm et al.1992)
(5x104 - 2x105 Zellen ml-1)
Prochlorococcus
Phylogeny
Sequencing of
several gene
fragments including:
16S rRNA, rpoC1,
psbA, glnB,
UreABCDEFG and
ITS approved the
statement that
Prochlorococcus
emerges within the
“classical”
cyanobacteria clade
No phylogenetic
uniformity in
Prochlorophytes
Close phylogenetic relation with cyanobacteria
Partensky et al. (1999)
Phylum Chlorophyta:
green algae
Sexual reproduction:
•fusion of identical
cells (isogamy)
•fertilization of a
large non-motile cell
by a smaller motile
one (oogamy).
Life Cycle of Chlamydomonas, a unicellular green algae
Phylum Chlorophyta: green algae
("chlor" - green, "phyta" - plant).
•The most closely related
to plants,
•Includes unicellular,
colonial and multicellular
forms.
•Inhabit aquatic (mostly
freshwater) and damp
terrestrial environments.
•Many of the simpler
forms are symbionts,
e.g. some lichens,
•Alternation between
haploid (asexual) and
diploid (sexual)
multicellular generations.
Phylum Bacilariophyta: the diatoms
(" a little stick plant") -
•Unicellular aquatic
forms, some of the most
abundant protistan plant
organisms in the oceans
•shells of SiO2.
•Cells comprised of two
separate valves (shells).
Diatomaceous earth—
dead diatoms settle to
seafloor, collected and
used in abrasives
Plankton—abundant food
source for marine
organisms
Reproduction: vegetative
and sexual (auxospore)
Diatoms are traditionally divided
into two orders:
Centric diatoms (Centrales),
which are radially symmetric
Pennate diatoms (Pennales),
which are bilaterally symmetric.
Phylum Phaeophyta: brown algae
("phaeo" - brown, "phyta" - plant).
Multicellular, mostly marine
Underwater forests—habitats
Most contain the pigment
fucoxanthin, responsible for
the distinctive greenishbrown color
Kelp—food, habitats for
aquatic organisms
Reproduce by means of
flagellate spores
Of commercial importance to
humans (Pectin, alginin)
Phylum Rhodophyta: red algae
("rhod" - red, "phyta" - plant).
Mostly multicellular,
marine,
Most of the coralline
algae, which secrete
calcium carbonate
and play a major role
in building coral
reefs,
Commercial
importance : Agar,
carrageen, sushi
Sexual reproduction:
non-motile larger
female and smaller
male gametes
Phylum Pyrrophyta: the dinoflagellates
Flagellate protists with two
dissimilar flagella
(longitudinal and
transverse), mostly in
marine plankton
Most are unicellular forms
About half of all are
photosynthetic
Some species, called
zooxanthellae, are
endosymbionts of marine
animals and protozoa (coral
reefs).
Colorless predators on
other protozoa, and a few
forms are parasitic (e.g.
Oodinium, Pfisteria).
Some are bioluminescent
Red tide—population explosion
of certain types of
dinoflagellates. Kills large
amounts of fish. Depletes
water of oxygen and releases
toxins into the water.
Reproduction: vegetative through
fission or sexual