Unit 8 Flashcards

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1
Q

what is the purpose of microbes inhabiting plant tissues?

A

nutrient support for plants or pathogen protection

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2
Q

where does mutualism occur?

A

root nodules

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3
Q

what kind of plants do mutualism?

A

leguminous plants - legumes (soybeans, beans, peas)

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4
Q

what occurs for root module symbiosis?

A

association between legumes and N2 fixing bacteria

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5
Q

can legumes grow without nitrogen fertilizer?

A

yes
- reduces polluting effects of fertilizer runoff and saves money

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6
Q

what are microbes in symbiosis?

A

rhizobia

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7
Q

what do rhizobia do?

A

N2 fixing
- form large populations
- secrete rhicadhesin protein
- attach to root hairs

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8
Q

what do legumes do?

A

protect nitrogenase from oxygen

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9
Q

what is leghemoglobin?

A

oxygen buffer

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10
Q

what do the roots of leguminous plants secrete and what is the purpose?

A
  • secrete organic compounds
  • stimulate growth of diverse rhizosphere microbial community
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11
Q

what does parasitism in plants cause?

A

gal disease

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12
Q

what do Agrobacterium do?

A

form tumorous growth on diverse plants

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13
Q

Agrobacterium tumefaciens

A

crown gall disease

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14
Q

Agrobacterium rhizogenes

A

hairy root disease

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15
Q

what is Ti plasmid?

A
  • trasnferred DNA (T-DNA)
  • integrated into plant’s genome
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16
Q

what is the purpose of T-DNA?

A

genes for tumor formation and synthesis of modified amino acids called opines

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17
Q

what is the purpose of opines?

A

source of nutrients for A. tumefacien cells

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18
Q

what are modified Ti plasmids?

A

deleted disease genes
- keeps transfer genes

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19
Q

how to genes of interest get added to Ti plasmid?

A

genetic engineering

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20
Q

what are modified Ti plasmids used for?

A

construction of transgenic plants

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21
Q

mycorrhiza

A

plant + fungi interaction

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22
Q

what are the mutualisms between?

A

plant roots and fungi

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23
Q

are nutrients only transferred one way?

A

no
- both directions
- fungus transfer P and N from soil to the plant
- plant transfers carbs to fungus

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24
Q

what do microbes in mammals do?

A

help with digestion in mammalian gut

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25
Q

what do microogranisms have that help digest cellulose?

A

mammals lack enzymes to digest cellulose so they have genes that helps digestion of complex polysaccharides

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26
Q

what helps with digestion of polysaccharides?

A
  • glycoside hydrolases
  • polysaccharide lyases
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27
Q

what are ruminants?

A

herbivores that possess special digestive organs (rumen)

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28
Q

what are the dominant bacteria and archaea in rumen?

A

Firmicutes and Bacteroidetes
Methanogens

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29
Q

which microbe does not like cellulose and which animal does it not grown in?

A

Streptococcus bovis - not grow in grass-fed cows in large amounts

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30
Q

what does Streptococcus bovis love?

A

starch
- diet switched from grass to grains

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31
Q

what kind of bacteria is Streptococcus bovis?

A

lactic acid
- lactic acid acidifies rumen below normal pH
- acidification and inflammation of rumen

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32
Q

what do legume plants contain?

A

mimosine (amin-acid like)

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33
Q

what is mimosine converted to?

A

toxic compounds in rumen by existing microorganisms

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34
Q

what could Hawaii ruminants feed with?

A

legume
- they had bacteria that degraded toxic mimosine

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35
Q

what bacteria is inoculated with Hawaii ruminants?

A

Australiam ruminants
- restored ability to eat legume plants

36
Q

what is the human microbiome?

A

microbes of whole human body
- role in human health

37
Q

what did surveys of the human gut flora use?

A

16S rRNA gene sequencing and metagenomic analyses

38
Q

similarities in individuals are evident at which taxonomic level?

A

phyla

39
Q

what is found in a gut for those with low fiber diet?

A

bacteroidetes

40
Q

what do Bacteroidetes do?

A

eat intestinal mucosa which develops ulcerative colitis

41
Q

reduction of _________________ occurs

A

short chain fatty acids

42
Q

what occurs with low fiber diet?

A

butyrate levels drop
G-protein coupled signaling and histone deacetylase
- causes cancer, obesity and diseases

43
Q

how to study microbiomes?

A
  • feed people different foods
  • collect fecal matter
  • analyze samples
  • determine any changes
  • infected cultures with intestinal microbiota
  • determine how they colonize cells and type of inflammatory response
44
Q

how to solve Clostridium difficile?

A

transplant patients with fecal material form healthy person
- fecal in tablet form, use metagenomics and sequence microbiome to analyze, improvements made

45
Q

termites

A

special group of insects that established symbiotic association with protists and bacteria that degrade lignocellulose

46
Q

what occurs in insects’ gut?

A

fix N and participate in carbon metabolism

47
Q

what are dominant in insects’ gut?

A

methanogens and acetogens

48
Q

what is Hawaiian bobtail squid?

A

small marine invertebrate

49
Q

what colonizes squid?

A

Aliivibrio fischeri

50
Q

what is Aliivibrio?

A

light organs
- luciferase in bacteria that emits light upon induction with AHL quorum sensing molecules

51
Q

what is produced by squid to kill bacteria?

A

nitric oxide

52
Q

what happens after A. fischeri colonizes the light organ?

A

no levels diminish rapidly

53
Q

how does A.fischeri enter squid?

A

ciliated ducts

54
Q

biofilms

A
  • assemblages of bacterial cells attached to surface and enclosed in an adhesive matrix that is product of excretion by cells and cell death
  • matrix is mixture of polysaccharides, proteins and nucleic acids that bind cells together
55
Q

what do biofilms do?

A

trap nutrients for microbial growth and help prevent detachment of cells on dynamic surfaces

56
Q

what are biofilm highly tolerant to?

A

antibiotics and stressors

57
Q

microbes in biofilms

A
  • extracellular matrix genes for stress tolerance
  • express genes for enzymes that promote biofilms (attached) mode of life
58
Q

diguanylate cyclase

A

enzyme that creates c-di GMP (cyclic guanosine monophosphate)

59
Q

what does c-di-GMP do?

A

binds to transcriptional regulators and promotes biofilms formation

60
Q

c-di-GMP binding proteins

A
  • reduce activity of flagellar motor
  • regulate cell surface proteins required for attachment
  • mediates biosynthesis of extracellular matrix polysaccharides
61
Q

Pseudomonas aeruginosa

A
  • cystic fibrosis
  • famous biofilm former
  • AHL: intracellular inducer
62
Q

what does AHL do?

A

turns on gene DGC
- increased c-di GMP levels

63
Q

what does elevated c-di-GMP levels initiate?

A

the production of extracellular polysaccharide and decrease flagellar function

64
Q

why bacteria forms biofilms?

A
  • self-defence: biofilms microbes are resistnat to physical and chemical stressors
  • attachment to favorable niche: specific structures on biofilms help microbe to remain attached to nutrient rich surfaces
  • close association with kins: more opportunities for nutrients and genetic exchange
65
Q

mineral recovery and acid mine drainage

A
  • extract valuable metals from low-grade ores
  • ores have energy reservoirs for microbes: FeS2, metal-HS complexes
  • concentration of metal in ore is low
66
Q

what bacteria is used for metal leaching in ores?

A

Acidithiobacillus ferrooxidans
- acidophallic iron oxidizer

67
Q

what does Acidithiobacillus ferrooxidans oxidize?

A
  • arsenopyrite and release Au
  • uranium with O2 available (U4+ to U6+)
  • O2 reduced to H2O
68
Q

bioremediation

A
  • microbial cleanup of oil, toxic chemicals, or other enviro pollutants by stimulating activities’ of hydrocarbon-degrading microogranisms
69
Q

what are pollutants?

A

natural materials
xenobiotic chemicals

70
Q

what is the most successful process for cleaning up spills of crude oil or leakage of hydrocarbons from bulk storage tanks?

A

bioremedition

71
Q

what does oil-oxidizing bacteria do?

A
  • grows rapidly
  • supplies inorganic nutrients and oxygen
72
Q

what compounds can be oxidized rapidly?

A

non-volatile oil compounds

73
Q

what are not preferred microbial substrates?

A
  • branches chain and polycyclic hydrocarbons
74
Q

what happened with the accident in Mexico?

A
  • 35% of resulting hydrocarbons were comprised of low-molecular-weight components and natural gas
  • development of bacteria that can oxidize easily degraded and more recalcitrant hydrocarbon components
75
Q

what is bioremediation of pesticides?

A

oxidation via microorganisms for energy extraction

76
Q

what microbe dechlorinates pesticide aerobically?

A

Burkholderia

77
Q

what occurs dechlorination?

A

oxygenase breaks down aromatic ring and introduces compound into TCA cycle

78
Q

what are plastics examples of?

A

xenobiotics

79
Q

what microbe breaks down and consume PET as carbon and energy source?

A

Ideonella sakaiensis

80
Q

what are the wastewater treatments?

A

physical and chemical methods
microbial treatment

81
Q

what does the pretreatment of wastewater involve?

A
  • mechanical processes to remove large debris and inorganic matter in water sample
  • remove highly toxic substances
82
Q

what is the secondary treatment processes?

A
  • series of degradative and fermentative reactions carried out by various prokaryotes under anoxic conditions
  • soluble components are fermented to yield mixture of fatty acids, H2 and CO2
  • then discharged into rivers and streams
83
Q

what does potable water require?

A

further treatment to remove pathogens
- filtration, chlorination and UV

84
Q

microbially influenced corrosion

A

metal corrosion by SRB
- use sulfate as TEA and produce H2S
- H2S is corrosive
- H2 and Fe0 are donor

85
Q

what is the MIC microbe?

A

Desulfopila corrodens