microbiome & contamination Flashcards
what is bioremediation
The clean up of oil or other toxic chemicals by microorganisms
microorganisms are used for bioremediation to
Transforming Heavy Metals (mercury)
Petroleum Biodegradation
Biodegradation of synthetic chemicals (xenobiotics)
true or false
mercury can be absorbed through the skin and could cause liver and kidney damage
true
how is mercury released into the environment
fossil fuel combustion and mining industry
atmospheric mercury is found in the form of: Hg0 – Vapour. whereas, oxidised mercuric form is Hg2+
Microorganisms – metabolize resulting in methylation - yields _________
methyl-mercury (CH3Hg+) which is a 100 X more toxic
which bacteria biotransform mercury to its non toxic form?
Pseudomonas aeruginosa
how can bioremediation of petroleum be accelerated?
adding nutrients and oxygen
what is the benefit of xenobiotics (pesticides)
prevent toxic accumulations and they eventually disappear from the soil
what is the role of polychlorinated biphenyls (PCB) xenobiotics in bioremediation
- Used as Industrial coolants or insulators
- Spills or leakage into the environment
- Eventually reaches groundwater
- Toxic, persistent and bio-accumulative
what types of biodegradable plastics are there?
- 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
define antibiotics
Chemicals produced by microorganisms that kill or inhibit growth of other microorganisms
true or false
Streptomycetes produce > 2 / 3 of clinically used antibiotics (non-synthetic)
true
Polysaccharides produced commercially used as a plasma substitute are known as
dextran
which bacteria produce dextran from sucrose?
Lactic acid bacteria (Leuconostoc)
what enzymes are often produced by streptococcal strains
streptokinase and streptodornase
what does streptokinase and streptodornase do
streptokinase, reduces blood clots
streptodornase, liquefies pus – breaks down deoxyribonucleoprotein and DNA
what type of pharmaceuticals do - Brevibacterium flavum - Corynebacterium glutamicum produce
amino acids
which microorganisms produce riboflavin (vitamin b2)?
mould: Ashbya gossipii
bacterium: Bacillus subtilis
which strains yield high amounts of cobalamin (vitamin b12)
Propionibacterium, Pseudomonas
what does Clostridium botulinum produce?
botulinum toxin, which causes severe food poisoning, paralysis, respiratory failure and death
which microorganisms produce insecticides
Bacillus thuringiensis and Bacillus sphaericus
what is the top fermenting yeast and bottom fermenting yeast
top: Saccharomyces cerevisiae
bottom: Saccharomyces carlsbergensis
“live micro-organisms which, when administered in adequate amounts, confer a health benefit on the host” are known as
probiotics
how can you reduce microbial count from water samples
- chemical treatment (chlorination/NaCl)
- membrane filtration (filter paper)
- heating (80c)
- uv irradiation (short wavelength (250 nm) - UVC
how can the operator reduce microbial count on themselves
- good hygiene
- covering when coughing and sneezing
- wearing gloves and protective garments
how can you reduce microbial count from surfaces
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
how can you reduce microbial count in air?
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
where is the normal flora located in the body
nasopharynx
small & large intestine
vagina
skin
urethra
stomach
what is the metabolic function of the gut microbiota
- 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).
what is the immune function of the microbiota
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.
define The Gut–Brain Axis
Bidirectional communication system that integrates neural, hormonal, and immunological signalling between the gut and the brain.
how does stress affect the gut microbiota?
- influences the composition of the gut microbiota
- influences the integrity of the gut epithelium and alter peristalsis, secretions, and mucin production
what is the function of mucins
- Glycoproteins that are expressed in cells
- Signal transduction
- Regulation of gene expression
- Cell proliferation
- Embryogenesis
- Cell differentiation
- Immunity
- Apoptosis
- Cancer
what is Irritable Bowel Syndrome
Crohn’s disease and ulcerative colitis) • Gut microbiota alteration linked to low-grade intestinal inflammation (inflammatory Bowel Disease)
what are the two Systemic Metabolic Diseases
obesity & diabetes type 2
true or false
Infants (1-12 months) with atopic eczema have a significantly lower bacterial diversity: Bacteroidetes and Proteobacteria
true
Proteobacteria cell walls contain lipopolysaccharides. in relation to eczema, what do lipopolysaccharides induce?
immune response
what causes pseudomembranous colitis?
antibiotic associated diarrhea, Clostridia difficile
