Chapter 10 Flashcards
ecology
study of the interrelationships that exist between organisms and their environment
microbial ecology
study of numerous interrelationships between microbes and the world around them
relationship between humans and microbes
- most are beneficial rather than harmful
indigenous microbiota
- aka normal flora, human microbiome
- all microbes (bacteria, fungi, protozoa, viruses) that reside on and in a person
- composed of 500-1000 different species
- blood, lymph, spinal fluid, and most internal tissues/organs are free of microbes
- destruction of resident microbiota disturbs delicate balance between host and microorganism
symbiosis
- two dissimilar organisms living together in close association
- organisms are referred to as symbionts
- many microorganisms participate
types of symbiotic relationships
- neutralism
- commensalism
- mutualism
- parasitism
- change in condition can cause relationship to shift to another type
neutralism
- symbiotic relationship in which neither symbiont is affected by the relationship
commensalism
- symbiotic relationship that is beneficial to one symbiont and of no consequence to the other
- many indigenous microbiota are commensals
mutualism
- symbiotic relationship the is beneficial to both symbionts
- lichens which are composed on fungus and algae
- humans and their intestinal bacterium (e coli)
parasitism
- symbiotic relationship that is beneficial to one symbiont (parasite) and detrimental to the other (host)
- host is living organisms that harbours another living organism
- parasite may or may not cause disease
transient microbiota
- micro-organism that take up temporary residence on and in humans
where most indigenous microbiota reside
- ears
- eyes
- mouth
- upper respiratory tract
- skin
- GI tract
- genitourinary tract
indigenous microbiota of skin
- primarily bacteria and fungi about 30 different types
- most commonly staphylococcus app.
- number and variety depends on moisture, temperature, pH, salinity, chemical wastes, and other microbes
indigenous microbiota of ears
- middle and inner ear usually sterile
- outer ear and auditor canal contain same microbes as skin
indigenous microbiota of eyes
- eye is lubricated and cleaned by tears, mucus, and sebum
- few microbes are present
microbiota of respiratory tract
- upper has abundance of microbes which are mostly harmless but some are opportunistic pathogens
- carriers often present in nasal passage or throat
- lower is usually free of microbes
carriers
- pathogens that do not cause disease but can be passed to others and cause disease
- ex: diphtheria, pneumonia, meningitis, whooping cough
indigenous microbiota of oral cavity
- provides shelter for anaerobic and aerobic bacteria
- remaining food particles provide nutrients for bacteria
- most common organism found in mouth is a-hemolytic streptococci
results of careless dental hygiene
- dental caries (tooth decay)
- gingivitis (gum disease)
- periodontitis
indigenous microbiota of GI tract
- large intestine contains largest number/variety of any colonized area with 500-600 species primarily bacteria
- colon is anaerobes so it is mostly obligate, aerotolerant, and facultative anaerobes
- many are opportunistic pathogens
indigenous microbiota of genitourinary tract
- kidneys, ureter, and bladder are usually sterile
- distal urethra and external opening harbour many microbes like bacteria, yeasts, and viruses
- most frequent include chlamydia trachomatis, neisseria gonorrhoea, and mycoplasmas
- male/femal repro systems are usually sterile with exception of vagina
benefits of indigenous microbiota
- vitamin K and B12
- microbial antagonism
microbial antagonism
- microbe vs microbe
- members of indigenous microbiota that prevent other microbes from becoming established
- ex: production of antibiotics and bacteriocins (antibacterial proteins); colicin produced by e coli
opportunistic pathogens
- pathogens that hang out and wait for an opportunity/change in environment to cause infection
- balance of indigenous microbiota can be upset by antibiotics, chemotherapy, an pH changes
- ex: e coli, enterobacteriaceae, s aureus, and enterococcus spp.
biotherapeutic agents
- aka probiotics
- bacteria and yeasts used to stabilize microbial balance
- take when on antibiotics to prevent opportunistic infection
biofilms
- complex communities of assorted organisms, they are everywhere
- consist of different species of bacteria which secrete gooey polysaccharide
- bacteria grow in tiny clusters called micro colonies separated by water channels
- ex: dental plaque
medical significance of biofilms
- they form on urinary catheters and medical equipment and can causes diseases like endocarditis
- very resistant to antibiotics and disinfectants
- antibiotics can be effective against pure culture bacteria but not the same bacteria in a biofilms due to different proteins produced in biofilm than pure culture
microbes commonly associated with biofilms
- yeast (candida albicans)
- staphylococcus aureus
- enterococcus spp.
- klebsiella pneumoniae
- pseudomonas aeruginosa
synergistic infections
- aka polymicrobial infections or mixed infections
- when 2 or more organisms team up to produce a disease that neither could cause alone
- referred to as synergism
- ex: acute necrotizing ulcerative gingivitis and bacterial vaginosis
endosymbionts
bacteria found within other microorganisms
role of microbes in elemental cycle
- microorganisms play role in cycling or nutrients and elements like nitrogen, carbon, O2, sulfur, and phosphorus
- some nitrogen fixing bacteria live in a near the root nodules of legumes like alfalfa, soybeans, and peanuts
gentrifying bacteria
- include some species of pseudomonas and bacillus
soil microbes
- bacteria, fungi, algae, protozoa, viruses, and viroids
- many are decomposers
- human pathogens live in soils like clostridium spp (c retain and c botulinum) and spores of bacillus anthracis
factors determining types and amount of microbes living in soil (7)
- amount of decaying matter
- available nutrients
- moisture
- O2
- pH
- temperature
- presence of waste products of other microbes
infectious diseases of farm animal
- caused by a wide variety of pathogens
- can be transmitted to humans
- economic concern to farmers and ranchers
microbial diseases of plants
- thousands of different plant diseases
- most are caused by fungi, viruses, viroids, and bacteria
biotechnology
- technological application that uses biological systems, living organisms, or derivatives to make or modify products or processes for specific use
- variety of industries like food, beverage, food additives, and antibiotics
- many antibiotics are produced in pharm companies by fungi and bacteria like penicillin
biotechnology for food
- bread, cheese, olives, pickles, vinegar, yogurt, butter, coffee, tofu, sot sauce, beer and wine
bioremediation
- use of microbes to clean up various types of wastes, including industrial and toxic waste and environmental pollutants like herbicides and pesticides
- some microbes are genetically engineered to digest specific wastes
- ex: petroleum-digesting bacteria to clean oil spills
methanotrophs
- bacteria that normally consume methane in the environment
- used to remove highly toxic solvents like trichloroethylene and tetrachloroethylene from the soil
nitrogen cycle
1) nitrogen fixing bacteria converts nitrogen into ammonia and ammonium
2) nitrifying bacteria converts ammonium into nitrite and nitrate ions
3) plants use nitrates to build proteins, animals eat plants and they build proteins
4) ammonification: animal waste products containing nitrogen are converted to ammonia
5) ammonia converted into nitrates and nitrites
6) dentrification: nitrates converted into atmospheric nitrogen by gentrifying bacteria
