Lectures 11-15 Flashcards Preview

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Flashcards in Lectures 11-15 Deck (83):
1

5 major fungi crop pathogens

Wheat stem rust, Rice blast, Potato late blight, corn smut, Soybean rust

2

Methods for classifying Microbial Diversity - Morphological

Features,structures, required microscopy

3

Methods for classifying Microbial Diversity - Metabolic

Biochemical, required enzymology

4

Methods for classifying Microbial diversity - Ecological

Extremophiles, required locations

5

Methods for classifying Microbial Diversity - Genetic

Gene sequences, required molecular biology,DNA sequencing, genome

6

Morphological Diversity

Coccus, Rod, Spirillum, spirochete, budding, filamentous. Only useful for prokaryotic/Eukaryotic

7

Metabolic diversity

Energy source (Chemotrophy or photography). Carbon source - Heterotrophs (organic) or autotrophs (CO2)

8

Ecological Diversity

Temperature- (Hyperthermophile or psychrophile)
Salinity- (Halophile)
pH - (Acidophile or alkaliphile)
Pressure - (Barophile)

9

Genetic Diversity

DNA sequencing lead to molecular phylogenetic trees
16S rRNA was chosen to be the chronometer

10

Biofuels created by fungi

Cellulases, ligninases, trichoderma reesei, endophytic fungi

11

Types of fungi disease

Irish potato famine - Caused by phytophtora infesting (oomycete)
Dutch Elm Disease - Ophiostoma ulmi
AIDS associated deaths -Cryptococcus immitis

12

Fungi's ability to infect

Immuno-compromised humans,
Greater threat in plants
Bioterrorism

13

Fungal Features

Monophyletic group
Diverged from animals 800-900 million years
Lack sequences controlling multicellularity

14

Taxonomy

Domain - Eukarya
Kingdom - Fungi
Phylum - Mycota
Class - Mycetes
Order - Ales
Family - Aceae

15

Further fungal features

Can be dimorphic.
They are Heterotrophs
Secrete enzymes through all, absorb soluble nutrients
Fungal wall (Chitin and glucans)
Fungal membrane - Ergosterol
Mannitol,trehalose, glycogen = storage
Produce sexual and asexual spores

Plastic genomes - Dispensable chromosomes, SNPs, retro DNA.
Large metabolic flexibility

16

Opisthokonts

Posterior flagellum, true fungi,chytrids,microsporidia collar flagellated protists are these. Animals aswell.

17

Types of Fungi

Chytridiomyctoa
Zygomycota
Glomeromyctoa
Ascomycota
Basidiomycota
Microsporidia

18

Microsporidia

Intracellular pathogens (animals and insects)
14 species infect humans
Smallest of eukaryotes
Unicellular spores
Lack mitochondria, peroxisomes and centrioles
Have prokaryotic features - 70S ribosomes
Have fungi features - Nuclear division, chitin, trehalose

19

What do protists have in common?

Eukaryotes
Water-based environment
Undergo mitosis
Most require oxygen
Unicellular
Motile

20

How do protists differ?

How they obtain nutrition - Phagocytosis, photosynthesis, absorption of nutrients, symbiosis

How they move - Pseudopodia, Cilia, Flagella

21

Alveolates

Sac below plasma membranes
Unicellular
Most photosynthetic

22

Alveolates (Dinoflagellates)

Marine, golden brown chloroplasts.
Two Flagella-Equatorial groove (Thurst and spin) and longitudinal grove (Rudder)
Amoeboid forms too
Producer of Organic Matter
Photosynthetic endosymbionts -corals
Associated with toxic red tides

23

Alveolates (Apicomplexans)

Apical complex (host invasion)
Parasites
Complex life cycles and multiple hosts
eg. Plasmodium

24

Alveolates (Ciliates)

Possess hair like cilia (short flagella) complex behaviour
Complex cellular forms, contractile vacuoles, digestive vacuoles
Two types of nuclei
Most are heterotrophic

25

Stramenophiles

Two flagella unequal length, rows of tubular hairs along larger flagellum
Some lost flagellum
Some photosynthetic

26

Stramenophiles (Diatoms

Unicellular but may associate in filaments
Carotenoids give brown colour
Only male gametes possess flagella
Two-piece silica cell walls
Bilateral or Radial symmetry
Synthesis Aquatic phytoplankton

27

Stramenophiles (Golden or Brown algae)

Marine
Multicellular filaments or fronts
Sessile or planktonic forms
Giant kelps
Fucoxanthin gives colour

28

Stramenophiles (Oomycota)

Water moulds
Saprobes and biotrophs
Cellulose cell wall

29

Haptophytes

Coccolithophores, chalk deposits
2 unequal flagella, both smooth
Have Haptonema, similar to flagellum but microtubules arranged differently
Red algal derived secondary endosymbionts

30

Rhizaria

Long, thin pseudopodia
Unicellular
Aquatic or soil living
Contribute to geological formations

31

Rhizaria (Cercozoans)

Aquatic or soil, green algal secondary endosymbionts
Predatory amoeboid and flagellates that feed by pilose pseudopods
Form silicaceous shell structures
Feeding from one end by no cytostome

32

Rhizaria (Foraminiferans)

Plantonic or sessile
External, spiral shells of calcium carbonate
Branching pseudopods, from sticking reticulate net
Limestone

33

Rhizaria (Radiolarins)

Marine heterotrophs
Silica
Thin, stiff pseudopods reinforced by microtubules
Radial symmetry
Largest Unicells

34

Excavates

Ancient
Lack mitochondria
Pathogens

35

Excavates (Diplomonads)

Unicellular, no mitochondria but contain mitsomes
2 nuclei of equal size
Multiple flagella

36

Excavates (Parabasilids)

Parabasal body
Have hydrogensomes
Genomes lack introns, genome 2x size of humans

37

Excavates (Heterloboseans)

Amoeboid, but unrelated to loosens. Do Primary Amoebaod Menginicepthalitis

38

Excavates (Euglenoids)

Primary flagellate with unique crystalline rod,
Rudimentary secondary flagellum
Mitochondria have distinct disk cristae
Cell shape determined by spiralling strips of protein
some photosynthetic

39

Excavates (Kinetoplastids)

Unicellular with two flagella
Mitochondria contain kinetoplast
Vector -borne pathogens

40

Amoebozoans

Closely related to opiisthokonts
Pseudopods for movement and feeding

41

Amoebozoans (Loboseans)

Naked or testate forms
Predators
Heterotrophic, phagocytosis
Free living
Disease causing

42

Amoebozoans (Plasmodial slime moulds)

Nuclear division without cytokinesis leads to coenocytic cells or plasmodia
Mass cytoplasmic streaming used for movement
Sclerotium resting structure
Stalked or branched fruiting structures

43

Amoebozoans (Cellular slime moulds)

Single celled haploid myxamoebae
Under nutrient starvation, they swarm to form pseudoplasmodium (Multicellular)
Slugs migrate
Produce a stalk and sporangium

44

Two types of growth

Isometric or polarised growth

45

Basic units of growth

Coenocytic or aseptic hyphae
Septate hyphae

46

How do they grow?

Hyphae contain microtubules, connecting compartments.
Hyphal tips are polarised, they change direction and show autotropism

47

Septa

Complete septa (Imperforate)
Regulated septa (Perforate)
Simple perforate in Ascomycota contain Woronin body
Septa in Basidiomycota are protected by a cap known as parenthosome- septa are dolipores.

Septa permit compartmentalisation and differentiation

48

Fungal cell wall

Made of Mannoproteins, chitin.

Maintenance of cell shape
Stabilisation of osmotic conditions
protection against physical stress
scaffold for proteins and enzymes

49

What drives Hyphal extension?

1) Turgor pressure
2) Vesicle supply centre or spitzenkorper

50

Hyphae can fuse (Anastomose)

Tip to tip
Tip to side
Self or non self
Sex (Clamp connections)
Conidial anastomosis tubes
Leads to fungal mycelium

51

Phases of mycelia growth

Lag phase, exponential, linear and deceleration

52

Limitations of mycelia growth

Resource unit restricted, fungi show heterogenous growth under restricted conditions

53

Different type of hyphae

Generative - Bear clamp connections or spores
Skeletal - long, unbranched thick of thin hyphae
Binding - Thick walled hyphae that branch

Fruitbody with Only generative has monomitic hyphal system.
Skeletal and binding are empty of cell contents (make it hard)

54

Other types or mycelial

Sclerotia -survival
Mycelial cords - Foraging
Rhizomorphs - foraging and translocation

55

Production or Asexual spores

Produced by conidiation
Known as conidia, yeast (Blastoconidia)

Higher fungi product complex multicellular structures to support spore production - Fruitbodies, Ascomata, basidiomata

56

Zygomycota

Contain sporoangia

57

Ascomycota

Contain ascocarp or conidia for asexual
Sexual spores are ascus 0 contain 8 ascospores. End of it is called operculum

58

Basidiomycota

Basidiocarp, basidiospore. Contain dikxaryotic mycelium.
Have thousands o sexes

59

Homothallic

Self fertile

60

Heterothallic

Sex requires partner

61

Monokaryon

Uninucleate haploid (n)

62

Dikaryon

Binuclear haploid (n+n)

63

Homokaryon

Uni or multi nucleate haploid (n)

64

Heterokaryon

Multinuclear (n+n)

65

Clamp connections

Maintain Dikaryon. Every hyphal compartment is binucleate
Dikaryon/heterokaryons established through somatogamous mating.

66

Badidiomycota

Spore droppers. Basidospores produce on basidia.
Homobadidiomycetes they are simple
Spore discharge is passive or by Buller's drop
In heterobasidiomycetes (Jelly fungi) complex

67

Bipolar Heterothallism

one mating-type gene, with two alleles are compatible.
AxA or axa incompatible

68

Tetrapolar heterothallism

Two mating type genes with two alleles. Only combinations that differ at all 4, will be compatible.

69

Secondary Homothallism

Bipolar meterothallic species, spores can form that segregate both mating types together. Mycelium is self fertile.

70

Chytridiomycota

Found in aquatic, parasites of algae.
Found I soils as saprotrophs
Some parasitic on vascular plants and amphibians

Simple microscopic moulds with chitin walls and swimming spores
4-6 losses of flagellum,
Simple strucutres, thallus becomes sporangium (zoospores)
Important in food webs

Scynchytrium
Potato Wart Disease
Black Scab

71

Zygomycota

Multinucleate mycelium - No septa = Coenocytic
Asexual spores in sporangium
Two hyphae fuse to form zygote
Some saprotrophic.
Found on mouldy fruit and bread.
Mucor on humans (Zygomycosis)

Rhizopus Oryzae
Phycomyces Blakesleanus
Mucor Circinelloides

72

Glomeromycota

Microscopic obligate intracellular mutualistica symbionts of al root plants (Form mycorrhiza)
Formation of arbuscules in roots
large, multi-nucleate; Spores with layered walls
Non- septet hyphae

73

Ascomycota

Largest group
Filamentous fungi and some yeasts
Licensed fungi
Septate hyphae
Carry sexual spores in ascus

Penicillium, Aspergillus
Edible
Neurospora
Candia albicans, Trichophyton
Ophiostoma

74

Dikarya basidiomycota

Diverse
Septum and dolipores
Sexual reproduction by basidiospores
Asexual reproductions - Clamp connections
Plant pathogens, Mushrooms

Puccinia gramminis - Wheat steam rust
Serpula lacrymans - Dry Rot
Armillaria - Honey fungus

75

Lichens

Crustose - Crust like adhere tightly to surface that they grow on
Squamulose - Scale like parts
Foliose - Leaf life, flat sheets
Fruticose - free standing branching tubes

Fungus and photosynthetic algal or cyanobacteria
Normally with ascomycota
Bioindicators
source of antibiotics
Disperse by soredia
are resistant

76

Aconidal

Lack of a sexual stage

77

Unikonts

Originally relative of opisthokonts so
Animals
All true Fungi (No moulds -pseudofungi)
Microsporidia
Chytrids (Moulds)
Collar flagellated protists (Choanoflagellates)
Choanozoa


78

Archezo are

Protists without mitochondria

79

Giardia, Trichomonas, Entamoeba and microsporidia were once united as

Archeozoa

80

Chromalveolates include

Apicomplexans
Dinoflagellates
Ciliates
Haptophtes
Heterokonts (stramenophiles)
Cryptophytes
Chromerida

81

Excavates HAVE

A single molecular tree

82

Primal Amoebic Meningoencephalitis is

Nigeria Fowleri - Infection of brain

83

Fungi Evolution

Derived from Water Moulds
Formed aseptate filaments
Septa
Clamp connections in Basidiomycetes
Asexual spores
Asci - Sexual spores
Fruiting Body
Holobasidium
Mushroom fungi