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PH1123 Microbiology > microbiome & contamination > Flashcards

microbiome & contamination Flashcards

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Biology 101 flashcards
1
Q

what is bioremediation

A

The clean up of oil or other toxic chemicals by microorganisms

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2
Q

microorganisms are used for bioremediation to

A

Transforming Heavy Metals (mercury)
Petroleum Biodegradation
Biodegradation of synthetic chemicals (xenobiotics)

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3
Q

true or false
mercury can be absorbed through the skin and could cause liver and kidney damage

A

true

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4
Q

how is mercury released into the environment

A

fossil fuel combustion and mining industry

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5
Q

atmospheric mercury is found in the form of: Hg0 – Vapour. whereas, oxidised mercuric form is Hg2+

Microorganisms – metabolize resulting in methylation - yields _________

A

methyl-mercury (CH3Hg+) which is a 100 X more toxic

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6
Q

which bacteria biotransform mercury to its non toxic form?

A

Pseudomonas aeruginosa

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7
Q

how can bioremediation of petroleum be accelerated?

A

adding nutrients and oxygen

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8
Q

what is the benefit of xenobiotics (pesticides)

A

prevent toxic accumulations and they eventually disappear from the soil

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9
Q

what is the role of polychlorinated biphenyls (PCB) xenobiotics in bioremediation

A
  • Used as Industrial coolants or insulators
  • Spills or leakage into the environment
  • Eventually reaches groundwater
  • Toxic, persistent and bio-accumulative
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10
Q

what types of biodegradable plastics are there?

A
  1. Photo-biodegradable: structure altered by sunlight (UV) - more amenable to microbial attack

2- 2. Starch-based plastic - starch used to link short fragments of a second biodegradable polymer

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11
Q

define antibiotics

A

Chemicals produced by microorganisms that kill or inhibit growth of other microorganisms

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12
Q

true or false

Streptomycetes produce > 2 / 3 of clinically used antibiotics (non-synthetic)

A

true

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13
Q

Polysaccharides produced commercially used as a plasma substitute are known as

A

dextran

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14
Q

which bacteria produce dextran from sucrose?

A

Lactic acid bacteria (Leuconostoc)

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15
Q

what enzymes are often produced by streptococcal strains

A

streptokinase and streptodornase

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16
Q

what does streptokinase and streptodornase do

A

streptokinase, reduces blood clots

streptodornase, liquefies pus – breaks down deoxyribonucleoprotein and DNA

17
Q

what type of pharmaceuticals do - Brevibacterium flavum - Corynebacterium glutamicum produce

A

amino acids

18
Q

which microorganisms produce riboflavin (vitamin b2)?

A

mould: Ashbya gossipii
bacterium: Bacillus subtilis

19
Q

which strains yield high amounts of cobalamin (vitamin b12)

A

Propionibacterium, Pseudomonas

20
Q

what does Clostridium botulinum produce?

A

botulinum toxin, which causes severe food poisoning, paralysis, respiratory failure and death

21
Q

which microorganisms produce insecticides

A

Bacillus thuringiensis and Bacillus sphaericus

22
Q

what is the top fermenting yeast and bottom fermenting yeast

A

top: Saccharomyces cerevisiae
bottom: Saccharomyces carlsbergensis

23
Q

“live micro-organisms which, when administered in adequate amounts, confer a health benefit on the host” are known as

A

probiotics

24
Q

how can you reduce microbial count from water samples

A
  • chemical treatment (chlorination/NaCl)
  • membrane filtration (filter paper)
  • heating (80c)
  • uv irradiation (short wavelength (250 nm) - UVC
25
Q

how can the operator reduce microbial count on themselves

A
  • good hygiene
  • covering when coughing and sneezing
  • wearing gloves and protective garments
26
Q

how can you reduce microbial count from surfaces

A

in buildings: proper ventilation, use of disinfectants, proper window fitting

in packaging: maintain integrity and shelf-life, delivery and limiting contamination measures

equipment: sterilization, disinfection, single use items

27
Q

how can you reduce microbial count in air?

A

filtration: High-efficiency particulate air (HEPA) filters can remove up to 99.997% of particles greater than 0.3 µm in diameter (high pressure too)

chemical disinfection

uv irradiation

28
Q

where is the normal flora located in the body

A

nasopharynx

small & large intestine

vagina

skin

urethra

stomach

29
Q

what is the metabolic function of the gut microbiota

A
  • Undertake a variety of metabolic functions
  • Provide vital biochemical pathways for the metabolism of non-digestible carbohydrates (cellulose, hemicellulose, pectins, and gums), some oligosaccharides, unabsorbed sugars, alcohols and host-derived mucins
  • Synthesis of vitamins - Enteric bacteria secrete Vitamin K and Vitamin B12
  • Stimulate the development of certain tissues (Caecum; caecum of germ-free animals is enlarged, thin-walled, and fluid-filled).
30
Q

what is the immune function of the microbiota

A

Produce antimicrobial compounds - Fatty acids and peroxides to highly specific bacteriocins.

  • Compete for nutrients and sites of attachment in the gut lining, preventing colonization by pathogens (barrier or competitive-exclusion effect)
  • Intestinal epithelium is the main interface between the immune system and the external environment.
  • Exposure to intestinal bacteria is also implicated in the prevention of allergy
  • The normal flora stimulates the production of cross-reactive antibodies.
31
Q

define The Gut–Brain Axis

A

Bidirectional communication system that integrates neural, hormonal, and immunological signalling between the gut and the brain.

32
Q

how does stress affect the gut microbiota?

A
  • influences the composition of the gut microbiota
  • influences the integrity of the gut epithelium and alter peristalsis, secretions, and mucin production
33
Q

what is the function of mucins

A
  • Glycoproteins that are expressed in cells
  • Signal transduction
  • Regulation of gene expression
  • Cell proliferation
  • Embryogenesis
  • Cell differentiation
  • Immunity
  • Apoptosis
  • Cancer
34
Q

what is Irritable Bowel Syndrome

A

Crohn’s disease and ulcerative colitis) • Gut microbiota alteration linked to low-grade intestinal inflammation (inflammatory Bowel Disease)

35
Q

what are the two Systemic Metabolic Diseases

A

obesity & diabetes type 2

36
Q

true or false

Infants (1-12 months) with atopic eczema have a significantly lower bacterial diversity: Bacteroidetes and Proteobacteria

A

true

37
Q

Proteobacteria cell walls contain lipopolysaccharides. in relation to eczema, what do lipopolysaccharides induce?

A

immune response

38
Q

what causes pseudomembranous colitis?

A

antibiotic associated diarrhea, Clostridia difficile

PH1123 Microbiology (9 decks)

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