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Copyright © 2014 Sinauer Associates, Inc. Cover photograph © Alex Mustard/naturepl.com. This document may not be modified or distributed (either electronically or on paper) without the permission of the publisher, with the following exception: Individual users may enter their own notes into this document and may print it for their own personal use.

The Origin and Diversification of Eukaryotes

0207

27.1 A Hypothetical Sequence for the Evolution of the Eukaryotic Cell (Page 550)

Cell wall DNA

The protective cell wall was lost.

1

Infolding of the

2

plasma membrane added surface area without increasing the cell’s volume.

Cytoskeleton (microfilament and microtubules) formed.

34

Internal membranes studded with ribosomes formed.

As regions of the infolded plasma membrane enclosed the cell’s DNA, a precursor of a

5

nucleus formed.
Microtubules from the cytoskeleton formed the eukaryotic flagellum, enabling propulsion.

6

Early digestive vacuoles evolved into lysosomes using enzymes from the early endoplasmic reticulum.

789

Mitochondria formed through endosymbiosis with a proteobacterium.

Endosymbiosis with cyanobacteria led to the development of chloroplasts.

Flagellum

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Chloroplast Mitochondrion

Nucleus

2

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chapter 27 the origin and Diversification of eukaryotes

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(A) Primary endosymbiosis

Eukaryote
Cyanobacterium

Cyanobacterium outer membrane

Peptidoglycan Cyanobacterium inner membrane

Host cell nucleus
Chloroplast

Peptidoglycan has been lost except in glaucophytes.

Chloroplastcontaining eukaryotic cell

(B) Secondary endosymbiosis

Host eukaryotic cell

Host membrane (from endocytosis) encloses the engulfed cell.

A trace of the engulfed cell’s nucleus is retained in some groups.

The engulfed cell’s plasma membrane (white) has been lost in euglenids and dinoflagellates.

27.2 Endosymbiotic Events in the Evolution of Chloroplasts

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Alveolates
Stramenopiles
Rhizaria Excavates Plantae Chs. 28 and 29
Amoebozoans
Fungi
Ch. 30

Ophisthokonts

Choanoflagellates
Animals
Chs. 31–33

Precambrian

  • Paleozoic
  • Mesozoic

Cenozoic

to 4.5 bya

  • 1.5
  • 1.4
  • 1.3
  • 1.2
  • 1.1
  • 1.0
  • 0.9
  • 0.8
  • 0.7
  • 0.6
  • 0.5
  • 0.4
  • 0.3
  • 0.2
  • 0.1
  • 0

Billions of years ago

27.3 Precambrian Divergence of Major Eukaryote Groups (Page 553)

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Dinoflagellates Apicomplexans
Ciliates

Stramenopiles
Rhizaria

In-Text Art (Page 553)

Peridinium sp.

Equatorial groove

Longitudinal groove

27.4 A Dinoflagellate (Page 554)

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chapter 27 the origin and Diversification of eukaryotes

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  • (A) Paramecium sp.
  • (B) Didinium nasutum
  • (C) Euplotes sp.

10 µm

27.5 Diversity among the Ciliates (Page 554)

  • 7 µm
  • 25 µm

  • Rows of fused cilia
  • Oral groove

  • Cilia
  • Bands of cilia

The macronucleus controls the cell’s activities.
Micronuclei function in genetic recombination.

Contractile vacuole

Alveoli
Cilia
Digestive vacuole

Oral groove

Trichocyst Fibrils
Anal pore
Pellicle
Alveolus

Cilium

27.6 Anatomy of Paramecium (Page 555)

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chapter 27 the origin and Diversification of eukaryotes

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INVESTIGATINGLIFE

27.7 The Role of Vacuoles in Ciliate Digestion

HYPOTHESIS The digestive vacuoles of Paramecium produce an acidic environment that allows the organism to digest food particles.

Method 1. Feed Paramecium yeast cells stained with Congo red, a dye that is red at neutral or basic pH but turns green at acidic pH.
2. Under a light microscope, observe the formation and degradation of digestive vacuoles within the Paramecium. Note time and sequence of color (i.e., acid level) changes.

Results

1 A digestive vacuole forms around yeast cells.

2 The change in color shows that the interior vacuole has become

Stained yeast cells

acidic.

Oral groove

As products of digestion move into the cytosol, the pH increases in the vacuole (the dye becomes red again).

3

Red-stained (basic) waste material is expelled.

4

CONCLUSION Some ciliates acidify digestive vacuoles to assist in the breakdown of food.

Go to BioPortal for discussion and relevant links for all

INVESTIGATINGLIFE figures.

(Page 555)

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Alveolates

Brown algae
Diatoms Oomycetes

Rhizaria

In-Text Art (Page 555)

25 µm

Diatoms display either radial (circular) symmetry...
...or bilateral (left-right) symmetry.

27.8 Diatom Diversity (Page 556)

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  • (A) Himanthalia elongata
  • (B) Postelsia palmiformis

Holdfasts

27.9 Brown Algae (Page 556)

Saprolegnia sp.

3 mm

27.10 An Oomycete (Page 557)

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chapter 27 the origin and Diversification of eukaryotes

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Alveolates
Stramenopiles

Cercozoans Foraminiferans Radiolarians

In-Text Art (Page 557)

1 mm

27.11 Building Blocks of Limestone (Page 557)

  • (A)
  • (B)

  • Astrolithium sp.
  • Hexacontium sp.

50 µm
250 µm

27.12 Radiolarians Exhibit Distinctive Pseudopods and Radial Symmetry (Page 557)

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Excavates

Diplomonads Parabasalids
Heteroloboseans
Euglenids
Kinetoplastids

In-Text Art (Page 558)

(A) Giardia sp.

2.5 µm

(B) T r ichomonas vaginalis

2.5 µm

27.13 Some Excavate Groups Lack Mitochondria (Page 558)

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Photosynthetic chloroplasts are prominent features in a typical Euglena cell.

Flagella
Nucleus

Pigment shield

Stored polysaccharides from photosynthesis
Contractile vacuole
Photoreceptor

27.14 A Photosynthetic Euglenid (Page 559)

TablE27.1

Three Pathogenic Trypanosomes

  • Trypanosoma brucei
  • Trypanosoma cruzi
  • Leishmania major

Leishmaniasis Sand fly

  • Human disease
  • Sleeping sickness

Tsetse fly
Chagas disease Assassin bugs (many species) None
Insect vector Vaccine or effective cure Strategy for survival

  • None
  • None

Changes surface recognition Causes changes in surface recognition Reduces effectiveness of macrophage

  • molecules frequently
  • molecules on host cell
  • hosts

  • Site in human body
  • Bloodstream; in final stages, Enters cells, especially muscle cells

attacks nerve tissue
Enters cells, primarily macrophages
Approximate number of deaths per year

  • 50,000
  • 45,000
  • 60,000

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chapter 27 the origin and Diversification of eukaryotes

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Amoebozoans

Loboseans
Plasmodial slime molds Cellular slime molds

In-Text Art (Page 559)

Chaos carolinensis

Pseudopods

Nebela collaris

120 µm

27.15 An Amoeba in Motion (Page 559)

Shell (test) made of sand grains

Plasma membrane of amoeba

Pseudopods of amoeba

18 µm

27.16 Life in a Glass House (Page 560)

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chapter 27 the origin and Diversification of eukaryotes

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(A)
30 mm
(B)

1.5 mm

27.17 A Plasmodial Slime Mold

(Page 560)

The sporangium of the mature fruiting structure will release spores.

Dictyostelium discoideum

Fruiting structure (various stages)

Slug
0.25 mm

27.18 A Cellular Slime Mold (Page 561)

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Macronucleus Micronucleus

1 Two paramecia conjugate; all but one micronucleus in each cell disintegrate. The remaining micronucleus undergoes meiosis.
2 Three of the four haploid micronuclei disintegrate; the remaining micronucleus undergoes mitosis.

3

The paramecia donate micronuclei to each other. The macronuclei disintegrate.

4

The two micronuclei in each cell—each genetically
5 The new diploid micronuclei divide mitotically, eventually giving rise to a macronucleus and the appropriate number of micronuclei. different—fuse.

27.19 Conjugation in Paramecia (Page 562)

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chapter 27 the origin and Diversification of eukaryotes

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START

Eventually, some merozoites develop into male and

8

A blood-feeding female mosquito ingests the

Plasmodium gametocytes.

1

Merozoites also invade red blood cells, grow and divide, and lyse the cells. They can reinfect the liver, producing new generations.

7

female gametocytes.

Male gamete

Within the mosquito, male and female

gametocytes develop

into gametes, which fuse.

2

Red blood cell
Female gamete

The resulting zygote

3

enters the mosquito’s gut wall and forms a cyst.

  • Events in human
  • Events in mosquito

Mosquito's gut wall

The zygote gives rise to sporozoites that invade the salivary gland.

4

Sporozoites penetrate liver cells and develop into merozoites.

6

(B)
Human liver cell
Mosquito's salivary gland

The mosquito injects sporozoites into a human’s blood when it feeds.

5
Cysts

27.20 Life Cycle of the Malarial Parasite (Page 564)

Mosquito's gut wall

170 µm

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chapter 27 the origin and Diversification of eukaryotes

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INVESTIGATINGLIFE

27.21 Can Corals Reacquire Dinoflagellate Endosymbionts Lost to Bleaching?

HYPOTHESIS Bleached corals can acquire new photosynthetic endosymbionts from their environment.

Method 1. Count numbers of Symbiodinium, a photosynthetic dinoflagellate, living symbiotically in samples of a coral (Briareum sp.).
2. Stimulate bleaching by maintaining all Briareum colonies in darkness for 12 weeks.
3. After 12 weeks of darkness, count numbers of Symbiodinium in the coral samples; then return all colonies to light.
4. In some of the bleached colonies (the experimental group), introduce Symbiodinium strain B211—dinoflagellates that contain a unique molecular marker. Do not expose the others (the control group) to strain B211. Maintain both groups in the light for 6 weeks.

Results

70

Experimental (exposed to strain B211)

60

Control (not exposed to strain B211)

50 40 30 20 10

Six weeks after return to light, both groups showed increases in number of symbionts present. DNA analysis showed that strain B211 symbionts were present in the experimental group.
After 12 weeks in dark, 0–1% of the photosynthetic endosymbionts remained.

3210

  • Pre-bleach
  • Post-bleach
  • Week 3
  • Week 6

(original state)

  • Pre-bleach
  • Post-bleach

CONCLUSION Corals can acquire new endosymbionts from their environment following bleaching.

Go to BioPortal for discussion and relevant links for all

INVESTIGATINGLIFE figures.

(Page 565)

© 2014 Sinauer Associates, Inc.

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  • Lateral Gene Transfer of Anion-Conducting Channelrhodopsins Between Green Algae and Giant Viruses

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  • Synchronous Exocytosis in Paramecium Cells. Vi. Ultrastructural Analysis of Membrane Resealing and Retrieval

    Synchronous Exocytosis in Paramecium Cells. Vi. Ultrastructural Analysis of Membrane Resealing and Retrieval

    J.CellSd. 77,1-17(1985) Printed in Great Britain © Company of Biologists Limited 1985 SYNCHRONOUS EXOCYTOSIS IN PARAMECIUM CELLS. VI. ULTRASTRUCTURAL ANALYSIS OF MEMBRANE RESEALING AND RETRIEVAL H. PLATTNER*. R. PAPE, B. HAACKE, K. OLBRICHT, C. WESTPHAL AND H. KERSKEN Faculty of Biology, University ofKonstanz, P.OJi. 5560, D-7750 Konstanz, Federal Republic of Germany SUMMARY After the synchronous induction of exocytosis of secretory organelles (trichocysts) in Paramecium tetraurelia cells the process of membrane resealing and retrieval could be followed under syn- chronous conditions. The characteristic aggregates of membrane intercalated particles (MIPs) contained within the freeze-fractured cell membrane (rings and rosettes) and trichocyst membranes (annulus MIPs), in addition to collar striations on the top of trichocyst membranes, served as endogenous ultrastructural markers. This allowed us to follow the re-arrangement of membrane constituents during and after exocytosis with high temporal and spatial precision. Membrane specificity is maintained to a considerable extent (~ 99-5 %), as judged from the rare occurrence of aberrant resealing (according to freeze-fracture data) and from the rather minute shift of glycocalyx components (according to electron staining experiments) during normal membrane resealing. Coated pits are not involved in membrane retrieval (155 ghosts analysed); since the membrane regions involved in exocytotic fusion are backed by apposed materials, probably proteins, this may restrain membrane constituents from intermixing. Another factor for maintaining membrane specificity is the fact that resealing of the exocytotic opening occurs much more rapidly than in most other systems. The retrieval operates with a half-life of 3 (strain 75) to 9min (K401); the involve- ment of cortical microtubules in the retrieval can be largely excluded, since only two microtubules (of unidentified origin) were seen to approach ghost structures in 4074 cases analysed during this period of intense ghost retrieval.
  • Protist Review.Pdf

    Protist Review.Pdf

    Protists Termite mound Section 1 Introduction to Protists -!). )DEA Protists form a diverse group of organisms that are subdivided based on their method of obtaining nutrition. Termite colony Section 2 Protozoans— Animal-like Protists -!). )DEA Protozoans are animal-like, heterotrophic protists. Section 3 Algae—Plantlike Protists -!). )DEA Algae are plantlike, autotrophic protists that are the producers for aquatic ecosystems. Section 4 Termites Funguslike Protists SEM Magnification: 17؋ -!). )DEA Funguslike protists obtain their nutrition by absorbing nutrients from dead or decaying organisms. BioFacts • A protist that lives symbiotically Protists in termite gut in the gut of termites helps it LM Magnification: 65؋ digest cellulose found in wood. • The amoeba Amoeba proteus is so small that it can survive in the film of water surrounding particles of soil. • An estimated five million protists can live in one teaspoon of soil. 540 (t)Oliver Meckes/Nicole Ottawa/Photo Researchers, (c)Gerald and Buff Corsi/Visuals Unlimited, (b)Michael Abbey/Photo Researchers , (bkgd)Gerald and Buff Corsi/Visuals Unlimited Start-Up Activities Classify Protists Make this LAUNCH Lab Foldable to help you organize the characteristics of protists. What is a protist? The Kingdom Protista is similar to a drawer or closet in which you keep odds and ends that do not seem to fit any other place. The Kingdom Protista is composed of three groups of organisms that do not fit in any STEP 1 Fold a sheet of notebook paper other kingdom. In this lab, you will observe the three in half vertically. Fold the sheet into thirds. groups of protists. Procedure 1.
  • Protistology the Taxonomic Position of Klosteria Bodomorphis Gen. and Sp. Nov. (Kinetoplastida) Based on Ultra Structure And

    Protistology the Taxonomic Position of Klosteria Bodomorphis Gen. and Sp. Nov. (Kinetoplastida) Based on Ultra Structure And

    Protistology 3 (2), 126-135 (2003) Protistology The taxonomic position of Klosteria bodomorphis gen. and sp. nov. (Kinetoplastida) based on ultra- structure and SSU rRNA gene sequence analysis Sergey I. Nikolaev1, Alexander P. Mylnikov2, Cedric Berney3, Jose Fahrni3, Nikolai Petrov1 and Jan Pawlowski3 1 A. N. Belozersky Institute of Physico-Chemical Biology, Department of Evolutionary Biochemistry, Moscow State University, Moscow, Russia 2 Institute for Biology of Inland Water RAS, Borok, Russia 3 Department of Zoology and Animal Biology, University of Geneva, Switzerland Summary A small free-living marine bacteriotrophic flagellate Klosteria bodomorphis gen. and sp. nov. was investigated by electron microscopy and molecular methods. This protist has paraxial rods of typical bodonid structure in the flagella, mastigonemes on the anterior flagellum, two nearly parallel basal bodies and discoid mitochondrial cristae. The flagellar pocket and cytostome/cytopharynx complex are supported by two microtubular roots and reinforced microtubular band (mtr). These features confirm that K. bodomorphis is a bodonid related to Bodo. However, the presence of a layer of dense glycocalyx on the flagella and one battery of cylindrical trichocysts with reticular walls makes it more similar to Rhynchobodo/Phyllomitus, although this flagellate characterized by pankinetoplasty. Phylogenetic analysis using the SSU rRNA gene is congruent with the ultrastructural studies and strongly confirms the close relationship of K. bodomorphis to the genus Rhynchobodo within the order Kinetoplastida. Key words: Bodonidae, Klosteria bodomorphis, evolution, 18S rDNA, phylogeny Introduction of kinetoplastid and related flagellates have been reinvestigated by electron microscopy (Brugerolle et al., Free-living kinetoplastids, especially bodonids 1979; Brugerolle, 1985; Mylnikov, 1986; Mylnikov et al., (Bodonidae Hollande), are an important component of 1998; Elbrächter et al., 1996; Simpson et al., 1997; marine ecosystems.
  • Trichocysts—Paramecium’S Projectile-Like Secretory Organelles Reappraisal of Their Biogenesis, Composition, Intracellular Transport, and Possible Functions

    Trichocysts—Paramecium’S Projectile-Like Secretory Organelles Reappraisal of Their Biogenesis, Composition, Intracellular Transport, and Possible Functions

    Erschienen in: Journal of Eukaryotic Microbiology ; 64 (2017), 1. - S. 106-133 https://dx.doi.org/10.1111/jeu.12332 Trichocysts—Paramecium’s Projectile-like Secretory Organelles Reappraisal of their Biogenesis, Composition, Intracellular Transport, and Possible Functions Helmut Plattner Department of Biology, University of Konstanz, PO Box M625, 78457 Konstanz, Germany Keywords ABSTRACT Ca2+; calcium; ciliate; defense; dense core secretory vesicle; secretion; secretory This review summarizes biogenesis, composition, intracellular transport, and vesicle. possible functions of trichocysts. Trichocyst release by Paramecium is the fast- est dense core-secretory vesicle exocytosis known. This is enabled by the crys- talline nature of the trichocyst “body” whose matrix proteins (tmp), upon contact with extracellular Ca2+, undergo explosive recrystallization that propa- gates cooperatively throughout the organelle. Membrane fusion during stimu- lated trichocyst exocytosis involves Ca2+ mobilization from alveolar sacs and tightly coupled store-operated Ca2+-influx, initiated by activation of ryanodine receptor-like Ca2+-release channels. Particularly, aminoethyldextran perfectly mimics a physiological function of trichocysts, i.e. defense against predators, by vigorous, local trichocyst discharge. The tmp’s contained in the main “body” of a trichocyst are arranged in a defined pattern, resulting in crossstriation, whose period expands upon expulsion. The second part of a trichocyst, the “tip”, contains secretory lectins which diffuse upon discharge. Repulsion from predators may not be the only function of trichocysts. We consider ciliary rever- sal accompanying stimulated trichocyst exocytosis (also in mutants devoid of depolarization-activated Ca2+ channels) a second, automatically superimposed defense mechanism. A third defensive mechanism may be effectuated by the secretory lectins of the trichocyst tip; they may inhibit toxicyst exocytosis in Dileptus by crosslinking surface proteins (an effect mimicked in Paramecium by antibodies against cell surface components).