Term
| There are several virulence factor strategies which microbes can use to evade the host, name about ten of them and provide a breif description |
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Definition
1. Pili and Fimbria-allow microbe to adhere
2. nonfimbrial methods such as receptors on the microbe which can form tight bonds with the hsot
3. Antigen variation
4.Capsule Formation
5. Proteases and Hydrolytic enzymes
6. sIgA proteases
7. Biofilms
8. Iron abstinence
9. binding to M cells
10. invasins
11. toxic proteins- these can kill phagocytes and reduce oxidative burst.
12. superoxide mutase -reduces oxidative burst\
13. sidenphores, use of tranferrins lactoferrin, and other iron binding proteins.
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Term
| Briefly describe the stages which cultural bacterial cells go through? |
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Definition
| Lag phase, logaritmic, exponential stage, transition, stationary and death. During the stationary stage things like gene expression for adhesins can be occuring and during stationary stage enzymatic enzymes might be in the processes which encode for toxins and others for spreading. |
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Term
| Another way microbes can evade the host mechanism of defense is by having what kind of receptors on its cell surface? |
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Definition
| antibody-enzymatic proteins which degrade the antibody. |
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Term
| Preinfections refers to survival in external environment, however there are many setbacks. Say a few and describe the means by which microbes help themselves survive? |
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Definition
| Some setbacks that microbes face are lack of nutrition in the wild, predators, toxins and chemicals, no means of attachment like those which are found in the host. some ways to compensate are by infecting a host as a parasite and utilizing its resources instead. other ways include forming endospores to protecet them from environment. still other ways include forming biofilms and secondary metabolites. |
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Term
| What are secondary metabolites? |
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Definition
| Secondary metabolites are things that microbes produce like acid, toxins, bactericins, antibacterial peptides and things of that sort to protect themselves from other noxious substances and microbes. |
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Term
| Explain what the efflux pumps are used for? |
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Definition
| Efflux pumps are associated with antibiotic resistance. they are f0ound on the membrane and help to pump toxins out from the cytoplasm into the envionment removing antibiotics. |
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Term
| What are biofilms and give examples of two microbes which are known and are of important medical importance? |
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Definition
| Biofilms are communuties of dense multilayers organisms whcih can attach to surfaces and be resistant to bacteria. they are often times hard to treat and two examples are Legionalla and Puesodmonas Auerguinosa in burn patients. Often times legionella can still be foound in the cooling vents because of this. Another example of biofilms is dental tars. |
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Term
| What is one complication with biofilms other than antibiotics resistance? |
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Definition
| Phagocytes cannot engulf them because they are too big. |
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Term
| Movement and Chemotaxis of microbes. Explain flagellum. |
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Definition
| Flagellum consists of polymerized flagellin protein which has a hook like structure for ATP synthase and propels the microbe forward. Some species can have multiple flagellum such as Ecoli and Niserria. |
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Term
| Describe other means of motility with reference to microbial 'sensing" and other shapes of flagellum? |
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Definition
| Well, movment of microbes of ten involves sensing light, oxygen, a magnetic field or some kind of chemical. autotaxis, chemo, etc. photo. the spiral and cork-screw shape are good ones to travel through mucus and so efficient that when placed in salin solution can begin to vibrate in place. this enables them from blood to tissue in the the endothelial cells lining blood vessels. |
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Term
| Why is the bladder a good place to thrive and give a microbe that does thrive there. What must you be able to do to stay in the bladder? |
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Definition
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Term
| How must a microbe penetrate if the skin is intact? |
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Definition
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Term
| How can a microbe penetrate the muscin layer and explain what it is? Name four different methods. |
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Definition
| the Mucin layer is a complex network of polysaccharide and protein. microbes can penetrate when 1) they don't have surface carboyhydrates which bind to this layer and can therefore easily penetrate. 2) when they have good motility (flagellum) and 3)they can move antiparrell to the globlet cells whcih make up mucin. 4) they can use M cells as their portal entry |
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Term
| Why is the intestine a safe haven for H. pylori and what causes this pH change? |
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Definition
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Term
| Why is it that when we're studying the mucosal surface that it is never clearly depicted in textbooks? |
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Definition
1) anything trapped there is removed immeditely.
2) in the repiratory tract you have this beating motion that gets rid of htem. 3) it really is a complex sturucture to study |
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Term
| Describe sIgA and how that contributes to the stickeness of mucin. How does it interact with pathogens AND antigens and what mechanism does it use to present these antigens to be trapped in mucin? |
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Definition
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Term
| What is the mechanism by which anitbacterial peptides can kill a cell? What do they form and as a result what is released from the bacterial cell? |
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Definition
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Term
| What are human antibacterial peptides called and describe their nature in comparison to he negatively charged bacteria. the formation of the pores as a result can also be described as a "__________" effect. |
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Definition
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Term
| How can the capsule formation limit the entry of a defensin which is often ciruclar in shape due to it's cationic structure. |
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Definition
| It prevents its diffusion into peptidolycan layer and so no pores are formed. |
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Term
| Name to subcategores of sideophores and explain how they function after release fro mbacteiral cell? They are the best-studied mechanism by which bacterial cells can " ___-________ iron." |
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Definition
| two subcategories incldue hydroxamates and catechols. |
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Term
| Iron acquisition can also occur in a surpisingly differnt way? How? Is it required though? |
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Definition
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