Chapter 1
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58 terms
Terms | Definitions |
|---|---|
 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 |
| Archaea | Which is referred to as archaebacteria, differ genetically & metabolically from true bacteria. Are considered to bridge a major gap in evolution between prokaryotes & eukaryotes. |
| Prokaryotes | 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. |
| Eukaryotes | Also possess a variety of organelles and subcellular structures like mitochondria, the Golgi apparatus, and the endoplasmic reticulum-like that lacking in prokaryotes. |
| Fungi | 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 | (1.) Gran-positive (2.)Gran-negative |
| Gram staining | The procedure used to distinguish between two types of bacterial cell wall structures is called ____________________. |
| Mycobacterium tuberculosis | 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. |
| Mycoplasma | 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. |
| Gram staining | technique that distinguishes two groups of bacteria because the stain reflects a basic difference in the composition of bacteria cell wall |
| Bacteria | 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) |
| Bacteria | Are about 1 to 5 ¥m across the largest dimension of the cell |
| Bacteria`s shapes | Coccoid or spherical, bacillary or rod-shaped, fusiform or long thin rods that taper at the ends,helical or corkscrew shaped |
| Gram-positive | Bacteria posses a single plasma membrane,or cytoplasmic membrane. |
| Gram-negative | Bacteria are characterized by the presence of 2 membranes, a cytoplasmic membrane and an outer membrane. Also produces - lipopolysaccharide (LPS) |
| periplasmic space | The space between the cell membrane and the outer membrane in Gram-negative bacteria that is filled with periplasm |
| Lipopolysaccharide (LPS) | 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 |
| Phyromonas gingivalis | 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. |
| Gram-negative bacteria | 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. |
| Peptides | 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 |
| Capsules | 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). |
| Glucans | 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. |
| Fructans | Function as extracellular storage compounds that allow the organisms to accumulate carbohydrates in a form that will not readily diffuse away from plaque. |
| Fimbriae | Of many oral bacteria mediate adhesion to salivary proteins; |
| Pili | 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) |
| Fibrillar layers | 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) |
| Flagella | Are organelles of locomotion produced by many differant species of bacteria,but only a relatively small subset of oral species produce flagella. |
| pertrichous flagella | many flagella all over cell |
| Spirochetes | Strong correlated with colonization of bacteria, |
| Vesicle | 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 |
| S-layers | Highly ordered proteinaceous coat that covers the surface of the bacteria. Coat on outside/protects cell |
| Endospores | 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. |
| DNA | 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 |
| Oxygen | Environmental factor that has a major impact on microbial growth. |
| Bacteria | Actually required oxygen for growth because of organisms respire to generate energy and use oxygen as a terminal electron acceptor. |
| Anaerobes | 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. |
| Microaerophilic | Some bacteria that require but can only toerate small amounts of oxygen |
| Capnophilic | Organisms that have their growth enhanced by carbon dioxide |
| Oral capnophiles | Actinobacillus actinomycetemcomitans and capnocytophaga gingivlis, both of which are associated with human periodontal disease |
| PTS | 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. |
| Microbial biofilm | 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. |
| Veillonella parvula | Which consumes lactic acid |
| S. Mutants & veillonella species | Strong association with dental caries. |
| P. Gingivalis & spirochetes | In periodontal diseases are well documented |
| Antagonistic interactions | Can also influence the composition and biological activities of the oral biofilms on teeth and soft tissue. |
| Carbohydrates | 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. |
| S. Mutants | Produce bacteriocins known as mutacins, which are peptide antibiotics that specifically inhibit the growth of closely related species. |
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