Anthony van leeuwenhoek
Renaissance Dutch inventor, perfected the microscope and was first to see cells and microorganisms which he called "animalcules"
Today life on earth divided into 3 primary domains:
(1.)Eukarya which are eukaryotes
(2) Bacteria & Archaea which are prokaryotes
Which is referred to as archaebacteria, differ genetically & metabolically from true bacteria. Are considered to bridge a major gap in evolution between prokaryotes & eukaryotes.
Are distinguished from eukarotes, members of the domain Eukarya, most notable by lack of a nuclear membrane, which separtes the chrosomal DNA of the organisms from the cytoplasmic contents.
Also possess a variety of organelles and subcellular structures like mitochondria, the Golgi apparatus, and the endoplasmic reticulum-like that lacking in prokaryotes.
Which are eukaryotic microorganisms, can also be present in the mouth, but generally are there low number's and flourish only when there is a restriction of access to saliva or a reduction in immunological competence.
2 categories of bacteria
The procedure used to distinguish between two types of bacterial cell wall structures is called ____________________.
Which has a cell envelope made of mycolic acid and waxes, making it substantially differant from most bacteria. Instead of gram staining, mycobacteria can be stained by the Ziehl-Neelsen staining technique, which is called acid fast staining.
Species and closely related organisms are completely devoid of a cell wall, and thus,these organisms are negative in the Gram reaction even though genetically they are more closely related to a gram-positive bacteria.
technique that distinguishes two groups of bacteria because the stain reflects a basic difference in the composition of bacteria cell wall
That grow optimally at PH values around 2 (acidophiles), where others will only grow Well at PH values near 10 (alkalophiles). Some prokaryotes grow very Poorly at temperatures above 15C (psychrophiles), where is some thrive at 100C in hydrothermal vents miles below the surface of the ocean (thermophiles)
Are about 1 to 5 ¥m across the largest dimension of the cell
Coccoid or spherical, bacillary or rod-shaped, fusiform or long thin rods that taper at the ends,helical or corkscrew shaped
Bacteria posses a single plasma membrane,or cytoplasmic membrane.
Bacteria are characterized by the presence of 2 membranes, a cytoplasmic membrane and an outer membrane. Also produces - lipopolysaccharide (LPS)
The space between the cell membrane and the outer membrane in Gram-negative bacteria that is filled with periplasm
part of the outer membrane; a large complex molecule that contains lipids and carbs and consists of 3 components: Lipid A, a core polysaccharide, and an O polysaccharide
Which has been impacted in human periodontal diseases, produces an LPS that strongly stimulates bone resorption
Peptidoglycan or Murein
The material comprising the cell wall.
Cell wall lies between the inner & outer member & is held in place by covalently bound lipoprotein that anchors the wall to the outer membrane, with the protein portion bound to the wall & lipid portion buried in the outer membrane.
Are a crossed linked to various degrees, depending on the organism & growth conditions, & this cross linking gives the peptidoglycan a mesh-worklike structure that is flexable, yet strong.
Lipoteichoic Acids (LTA)
A major constituent of the outer envelope of gram-positive bacteria.LTAs are amphipathic molecules, they are composed of hydrophilic & hydrophobic constituents. Are thought to be important in conferring surface hydrophobicity to the bacteria, a trait that is strongly correlated with the ability to adhere to host tissue and saliva-coated teeth.
Teichoic acid TA
a negatively charged polysaccharide in the cell wall of gram positive bacteria
Which are produced by a wide variety of bacteria, are extracellular polymers that are loosely attached to the surface of the organisms. Generally, capsules are composed of polysaccharides.
Glucans and fructans
Are responsible for the "furry" feeling on your teeth after one consumes foodstuffs containing high concentration of sucrose. Can polysaccharide produced by oral bacteria represent a large proportion of the dry weight of dental plaques ( diet contains Sucrose).
Produced by S. Mutans cannot be digested by the enzymes of any known oral organisms or by salivary amylase, so once glucans are produced in the mouth, they must be removed by mechanical forces.
Function as extracellular storage compounds that allow the organisms to accumulate carbohydrates in a form that will not readily diffuse away from plaque.
Of many oral bacteria mediate adhesion to salivary proteins;
Appendages that allow bacteria to attach to each other and to transfer DNA
Fimbriae and pili
Often used interchangeably to refer to filamentous, or hair like structures on the surface of bacteria. They also mediatemany functions that are detrimental to the host, like induction of programmed cell death (apoptosis), stimulation of bone resorption, and facilitation of entry of the bacteria into cells of the host (invasion)
Gram -positive bacteria possess a fibillar layer. Or fuzzy coats, fuzzy appearance. Often composed of proteins that act as specific adhesin & directly mediate the binding of bacteria to host protiensor host cell. Hydrophobicity to the cell ( repel water)
Are organelles of locomotion produced by many differant species of bacteria,but only a relatively small subset of oral species produce flagella.
many flagella all over cell
Strong correlated with colonization of bacteria,
a small cavity or sac that contains materials in a eukaryotic cell; forms when part of the cell membrane surrounds the materials to be taken into the cell or transported within the cell. Gram-negative bacteria, tissue-damaging enzymes, and other virullence factors
Highly ordered proteinaceous coat that covers the surface of the bacteria. Coat on outside/protects cell
A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions. More commonly none as dormant forms of bacteria that is highly resistant to killing by physical or chemical agents heat,bleach,alcohol,proxides
The Bacteria chromosome
Bacteria have a single, covalently closed chromosome,there are some rare exceptions when the chromosomeal DNA is linear.
Adenine,(A), cytosine (C), guanine (G), and thymine (T), base
Gene exchange in bacteria
Can enhance the diversity of the population and allows the transfer of genes that can augment the virulence of organisms
Resistence to bacteria
Of certain traits that augment the virulence of the organisms
Bacteria divide by binary fission
Because one bacterium becomes two bacteria, cultures of bacteria
Environmental factor that has a major impact on microbial growth.
Actually required oxygen for growth because of organisms respire to generate energy and use oxygen as a terminal electron acceptor.
Cannot grow in the presence of oxygen, largely because they create toxic oxygen radicals through metabolism,but lack sufficient quantities of, or lack altogether, the enzymes needed to cope with oxygen radicals.
Facultative or facultatively anaerobic bacteria
(Adapt to their environment) can grow in the presence of oxygen but also grow well when oxygen is absent. Most of the abundant species in the mouth are faculative organisms, such as oral streptococci.
Some bacteria that require but can only toerate small amounts of oxygen
Organisms that have their growth enhanced by carbon dioxide
Actinobacillus actinomycetemcomitans and capnocytophaga gingivlis, both of which are associated with human periodontal disease
Has many important roles in oral bacteria, but especially critical pathway when nutrients become limited be a use it will allow oral bacteria to scavenge the trace amounts of carbohydrates that are present in the mouth between periods of food consumption.
Organisms colonizing a surface and embedded in a polymer-rich matrix," dental plaque being an archetypical example of biofilm. - is center al to understanding oral microbial ecology & oral disease development.
Which consumes lactic acid
S. Mutants & veillonella species
Strong association with dental caries.
P. Gingivalis & spirochetes
In periodontal diseases are well documented
Can also influence the composition and biological activities of the oral biofilms on teeth and soft tissue.
Leads to bacterial production of organic acides, such as lactic and acetic acids,which in turn drives the Ph of the oral biofilm down to value of 4 and below.
Produce bacteriocins known as mutacins, which are peptide antibiotics that specifically inhibit the growth of closely related species.