Fungi- intro Flashcards
fungi roles
- recyclers
- provide us with food
- medicines
- enzymes
- model organisms
- villains of crop disease
- villains of wild life disease
food production needs to
double within the next 50 years - challenge to food security
challenges to food security include
water crisis, energy costs, land degradation, political conditions, climate change, pests and pathogens
fungi are the biggest threat to
global food security out of all microorganisms
where are pathogens moving
polewards in a warming world. also an increasing number at high latitudes
–> mean shift of 3km per year, since 1960
5 most devastating crop pathogens
wheat stem rust, rice blast, potato late bought, corn smut, soybean rust
annual loss due to these pathogens is sufficient to feed
600-4,000 million people per year
which fungal disease is the most devastating int he EJ
Zymoseptoria tritici
Zymoseptoria tritici is
fungicide resistance
fungi threaten ecosystem
resilience
Ash dieback, UK
80 million ash trees in the UK. Fungus ‘arrived’ in 2012. Over 1000 sites infected (2017). Only 2% of ash trees remain in areas of int and east anglia
medical mycoses e.g.
Trichophyton rubrum –> fungal nail disease
microbes dominant
earths biodiversity
guns can range from
single cells to enormous chains of cells that can stretch for miles.
methods of microbiology
microscopy, sterilisation, pure culture methods and molecular biology
confocal microscopy (AFM and NMR)
specificity, resolution and lice ell imagery
sterilisation and axenic culture
using autoclaves and microbiological filters
hypothesis for the origin of life
RNA world–> RNA was first form of genetics and then DNA took over because it was more stable
how many species
10+ million to a trillion species
how many known species
1.5 million
how many new species name a year
7- 10,000 new species
99% of all species that have been on earth are
extinct
how many microbes
100 billion to 1 trillion
microbes adapt to their environment resulting in
diversity
way of classifying microbial diversity (4)
morphological diversity, metabolic diversity, ecological diversity, genetic diversity
morpholigical
key advance being microscopy
metabolic diversity
biochemical and0 key advance being enzymeology
ecological diversity
e.g. extremophiles
genetic diversity
key advances- molecular biology, genome comparisons
halophile
microorganisms which can live in extremes of salinity
acidophile
microorganism which live in very acidic conditions
alkaliphile
microorganism which live in very alkaline conditions
barophile
microorganisms which live under extreme pressure
what allows for construction of molecular phylogenetic trees
alterations in DNA sequence
morphological diversity is sufficient for
distinguishing prokaryotic/eukaryotic and some obvious prokaryotic differences - metabolic differences can help to further distinguish
metabolic diversity- biochemical differences
1) energy source
2) carbon source
organic
heterotrophs
CO2
autotrophs
early models of phylogeny
2 kingdom model –> 5 kingdom model
5 kingdoms
plantae, fungi, animalia, protista, monera
why is rRNA an excellent chonometer
highly conserved and functionally constant
carl woese
sequences the 16s RNA from a broad array of microorganisms. 16s sufficient not to see many changes through evolution.
ribosomal RNA gene sequencing and phylogeny
1) ure culture and cells are lysed and dna isolated
2) gene encoding ribosomal RNA is isolated and amplified by PCR
3) amplified rRNA gene is sequenced
4) obtained sequences aligned by computer –> airways comparisons –> into tree of life
5) tree depicts differences in rRNA sequence between organisms
on the tree of life, the length of the line is proportional to
evolutionary distance
carl worse -rRNA analysis of methanogens
worse compared rRNA in bacteria and eukaryotes and produced association coefficients
according to Woese how similar and diff were euk and bacteria
0.3 similar and 0.8 diff
subunits of RNA polymerase in bacteria
4 subunits αββ’ð
subunits in eukarya RNA polymerase
101-2 subunits
what suggests archaea translation is more like eukarya than bacteria
inhibitors
order of classification
Domain Kindgom Phylum Class Order Family Genus species
fundamental differences in archael membrane
1) linkage of hydrophobic side chains
2) type of side chain
e. g. ester linkage bonds fatty acid to glycerol
- isoprene ins
ether linkage bonds side chain to
glycerol
how many subgroups in Archaea
2
2 groups of archaea
1) hyperthermophils- grow at higher temps
2) methanogens and extreme halophiles and acidophiles
archaea
16s
eukarya
18s
early branching in eukarya lack
mitochondria and other eukaryotic organelles
many early branching eukaryotes (protozoans) are
pathogenic parasite of humans (giardia, trichomonas)
though that Euk mitochondria and chloroplasts..
evolved from bacteria
those cells lacking mitochondria probably
lost rather than never acquired
early problems of tree of life
- is rRNA the complete story
- archaeal type gene encoding an enzyme would appear in bacteria
where does horizontal gene transfer occur more often?
prokaryotes
96% of all landplants
live in association with fungi –> mycorrhiza
fungi can grow in very toxic conditions and can remove..
metals and radioisotopes from solution
–> even uranium
Paul nurse
used the fungus fission yeast to investigate cell cycle
one-third of all AIDS associated with
death
humans and fungi
-more of a threat to immuno-comprimised and less of a threat than bacteria and viruses
plants and fungi
greater treat than nematodes, bacteria and viruses
morphology gives..
5 kingdoms: bacteria, protists, plants, fungi and animals
molecular data gives
3 domains: bacteria, archaea, eucarya
fungi are more closely related to..
animals than plants
fungal taxonomy
Domain- Eukarya Kingdom- Fungi Phylum- mycota subphylum- mycotina Class- mycoses Order- ales family- aceae Genus.. print in italics Species.. print in italics
unicellular growth
yeast
filamentous growth
tip growth of filaments hyphae giving rise to mycelium
dimorphic fungi
Blostomyces, coccidioides, histoplasma, Paracoccidioides, sporothrix
what decided whether a dimorphic fungi will take the unicellular or filamentous form
if it is grown in vitro (25 degrees) or in vivo (37)
fungi absorb
externally digested nutrients (animals engulf/ plants photosynthesise)
how do fungi absorb nutrients for growth
secrete enzymes through wall, absorb soluble nutrients through wall
fungal wall is made up of
chitina and glucans
fungal membrane
ergosterol (in animals- cholesterol)
what are storage compounds in fungus
mannitol, trehalose and glycogen
nuclei in fungi
haploid
which group shows that fungi and animals are closely related
Opisthokonts
Opisthokonts
are a broad group of eukaryotes, including both the animal and fungus kingdoms
what does opisthokonts mean
means “posterior flagellum’. All true fungi, chytrids, microsporidia, collar-flagellated protists and kingdom animalia
where are fungi thought to have diverged from
water moulds- oomycetes
fungal evolution
- fungi diverged from oomycetes
- formed aseptate filaments
- septa
- clamp connections in basidiomycetes
- asexual spores
- asci- sexual spores
- fruiting bodies
- holobasidum
- mushroom fungi
fungal phyla (6 or 7)
Chytridiomycota, Blastocladiomycota, Zygomycota, glomeromycota, ascomycota, basidiomycota, (microsporidia)
fungi and microsporidia are
closely related
microsporidia
obligate intracellular pathogens. infect animals and insects. smallest of all eukaryotes, unicellular spores.
how many microspordia species infect humans
14–> causing diarrhoea, eye, muscular, respiratory and genitourinary infections
microsporidia lack
mitochondria, peroxisomes, centrioles
which prokaryotic features does microsporidia have
70s ribosomes and sues 5.8s and 28s rRNA
fungal features of microsporidia
nuclear division, within an intact nuclear membrane, terhalose, chitin cell wall
6 main parts of the fungal kingdom
Chyridbiomycota Zygomycota Ascomycota Lichens Basidiomycota
