BIOLOGY 207: LECTURE 25
45 Cards in this Set
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Biofilms are
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Microbial life on suraces
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Types of surfaces and suitability for microbial reproduction
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Dry- generally NOT suitable for microbial reproduction
Wet- can be very suitable for microbial reproduction
in soils, lakes, streams, and all places where liquid exists (e.g. inside human body, mouth, genitourinary tract, intestine)
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Bacteria can live in how many diff states? what are they?
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___ can live in 2 different states - planktonic (dispersed in liquid)
and sessile - attached to surfaces covered by liquid
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Importance of surfaces for microbial survival and reproduction
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1. organic compounds adsorb to and accumulate on surfaces, so surfaces often contain more nutrients for microbial growth than plank tonic habitats
2. microbial cells can attach to surfaces, by attaching, microbes can remain in habitat favorable for reproduction
3. in biofilms, bacteria …
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general description of biofilm, sturcture
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a "microbial slime" forming on surfaces in aqueous environments
assemblage of surface-associated microbial cells enclosed in a matrix of extracellular polymeric substance (EPS, mostly polysaccharide)
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a bacterial biofilm can be made up of _____ (where common) are important _____
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can be made up of a single bacterial species (common in human disease)
or community of microorganisms common in environment)
important ecologically, indstrially and in human health
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biofilms and importance in what industries, description
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defense- navy effort on developing anti-fouling paints, to allow ships to move through water more easily (less fuel)
industry- lost industrial productivity, equipment damage, corrosion, cots of repair and maintenance
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biofilms + medicine/human health
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biofilms play a crtic role in hman health- lives lost and teartment costs
bacterial infections - implants, secondary infectiosn
reduced effectiveness of antiobitic therapy
reduced effectiveness of immune response
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some biofilm diseases
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gingivitis, peridontal diseas and dental carries
otitis media (acute ear infection
bacterial endocaditis
cystic fibrosis
legionnare's disease
nosocial (hospital aquired) infetions - catheters, medical implants, wound dressings, tracheal inserts
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bacteria in biofilms + antiobitics why?
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bacteria in biofilms are highly resistant to antibiotics - need high and/or long term doses of antibiotics to treat
-thickness of biofilm
-difficulty of diffusing through EPS
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Biofilms composition
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layers of "slime" composed of microbial cells and EPS in clumps, mushroom and pillar-like structures sepreated by water filled splores
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Gingivitis and periodontal/gum disease implications
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arise from poor dental hygiene i,e, plaque build up
gum disease has major effect on cardiovasicular and pulmonary health
bacteria from the plaque enter bloodstream through swollen, infected gum tisseu and can lodge in tissues of heart
bacteria from plaque enter lungs via breath and ca…
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link btwn gum disease and terminal illness
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people with gingivitis - 23 % higher risk
people with periodontal disease - 50% higher risk
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definition of human microbiome
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ecological community of commensal, symbiotic, and pathogenic microorganisms that share our body space
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sites of human body inhabited by microbes
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skin, mouth, nasal cavities, throat, stomach intestines, urogential tract
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number of microbes in and on human body
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approx 10^14 (100 trillion)
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Normal microbial residents of the human body serve as, what is this called?
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serve to block entry or growth of pathogens
non specific defense
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Normal microbial residents of the human body, where and hat purpose
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present in regions of body normally exposed to environment
skin, oral cavity, upper respiratory tract, intestinal tract, urogenital tract
benefical are important for a normal state of health
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normal microbial residents in gut tract (what do they do)
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vitamin synthesis
synthesis of enzymes (breakdown of certain carboyhydrates) and solubilzation of fats
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normal microbial residents on skin/intestine/urogenital tract + elsewhere
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preemption of living space and attachment sites that could be used by pathogens;
alteration of physiological coniditions (pH, oxygen tec.) such that growth of pathogens is inhibited
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Factors influencing non-specific defense
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age- establishment of normal resident microbes in newborn children, general vitality and vitality of immune system in elderly people
stress- fatiguem inadequate, dehydration, tension etc. predispose a person toward infetion and disease
diet - adequate protein, minerals, vitamins
e…
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damaging/weakening of non-specific defense can
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can lead to invasion of body by pathogenic bacteria, survival and growth in the body, and the initiation of disease
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Skin + microbes associated with
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___ resident on skin mostly are associated with the sweat glands and sebaceous glands of hair follicles
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secretion of skin glands are rich in
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urea, amino acids, salts, lactic acid, lipids, PH 4-6
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most resident microbes of skim are
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gram positive (staphylococcus, corynebacterium, propionibacterium)
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surface of the skin (upper layer of epidermis) is
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dry and shed continuously
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skin provides, what is skin?
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provides a major barrier to invasion of the body by microbes
is a non-specific defense- a physical barrier w/ presence of normal resident microbes, presence fatty acids and lactic acid
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Human Skim Microbiome (mostly what kind of bacteria, composition)
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mostly gram positive bacteria
composition of microbial community varies w/ type of skin]
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Respiratory tract + resident microbes
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mucous membranes in respiratory tract support growth of resdient microbes
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Upper respiratory tract (what are components, relation w/ bacteria)
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sinuses, nasopharynx, pharynx, oral cavitiy, larynx
bacteria enter by air, are trapped in nasal passages and removed in nasal secretions
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Resident microbes in respiratory trat
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staphylococcus, streptococcus, normally present and some are potentially harmful, but usually do not cause illness; other resident microbes and the immune system keep them in check
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Lower respiratory tract(what are components, relation w/ bacteria)
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trachea, bronchi, lungs
essentially sterile, cilia line respiratory tract, beating upward, removing particulates and bacteria; mucociliary clearance
non-specific defense- mucous (traps microbes) cilia( remove them)
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saliva + bacteria
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saliva provides nutrients for bacteria
waters, salts, low levels of carbs, proteins, urea, ammonia, amonio acids, viamins
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lysozome, lactoperoxidase (what are they, what do they do)
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disrupts peptidoglycan of bacterial cell wall
generates singlet oxygen
enzymes are antibacterial
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Streptococcus role in dental carries
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single cells attach to tooth surface coated w/ salivary glycoproteins, grow to form microcolines held together w/ mucopolysaccharide slime
continued growth leads to plaque (biofilm) formation
filamentous forms, fusobacterium, actinomycetes, spriochates (Borrelia) and many other types jo…
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Implications of diet high in scurose
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promites bacterial plaque formation (a biofilm) and bacterial fermentation of sugar to lactic acid dissolves tooth enamel
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urogential tract + bacteria (bladder, urethra, non-specific defense)
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bladder usually sterile (no bacteria or yeast)
urethra has some gram-negative facultatively aerobic bacteria
can become opportunistic pathogens
non-specific defense- urination (flushes out microbes
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gastrointestial tract + bacteria how many?
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large numbers of bacteria are present- 10^12 to `0^14 microbial cells in the total GI tract
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stomach + bacteria (non-specific defense)
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bacteria taken in w/ food, liquids, very few survive the low pH (pH of 2, non specific defense) due to secretion of HCL acid
some kinds of gram-positive and gram-negative bacteria do colinze stomach living in low numbers
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small intestine + bacteria
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duodenum, farily acidic, genrally has a low number of bacteria like stomach
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large intestine + bacteria
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colon, facultative aerobes (e. coli), consume all available oxygen, create conditions suitable for obligate anaerobes
jejunum to ileum, pH inreases, oxygen decreases, bacetial numbers increase
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facultative aerobes and obligate aerobes concentration per gram in large intestine
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facutlative aerobes -usually less than 10^7 per gram
obligate anaerobes - up to 10^10-10^11 per gram
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Numbers of bacteria in human gastroinestinal tract (stomach, jejunu, ileum, colon)
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stomach <10^4/g
Jejunum 10^3-10^4/g
Ileum 10^8
Colon 10^11-10^12
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what diseases do Intestinal bacteria influence? how might diseases be eliminated?
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obesity, inflammatory bowel diseas, type I diabetes, cancer, and liver disease
changing the composition of the gastroinestinal microbiome or introducing beneficial members of a normal gastroinestinal microbiome might eliminate these diseases
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Microbial composition of the human colon (what is it based on, what is it mostly?)
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based on 16s rRNA gene sequences
mostly gram positive
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BIOLOGY 207: LECTURE 25