Symbiosis – Microbiology Test Questions – Flashcards
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Unlock answerswhich 2 pigments are found in the skin secretion of the hippopotamus? |
norhipposudoric acid which is orange and hipposudoric aci which is red |
Which of the following is a virulence factor of Legion pneumonphilia? A. Activates apoptosis by up regulating apoptic genes B. Activates NF-kB pathway to maintain host cell survival C. Activates caspase-1 and -7 in human monocytes D. Does not promote the cleavage of Rabaptin-5 by Caspase-3 |
Answer is B |
________ are pores inserted into the plasma membrane leading to the osmotic lysis of the cell and release of the intracellular bacteria. |
Pore-forming toxin |
What hormone is secreted from adipose tissue and the stomach? |
Leptin |
Ghrelin is a hormone that stimulates what? |
food intake, reduce energy expenditure, and increases acid secretion. |
. If there is a lack of Mendelian segregation and Mendelian ratios what does this suggest in terms of microbial symbioses? |
cytoplasmic inheritance. |
What is the relationship between obesity Firmuctes and Bacteriodetes |
greater, fewer respectively |
H. pylori colonization has shown to affect expression of which two hormones associated with controlling appetite and satiety |
–leptin and ghrelin |
When is ghrelin released?- |
during fasting |
What fighting-cancer agent is found in broccoli? |
–sulforaphane |
What kind of prey do the Bdellovibrio bacteria prey upon? Do they show selectivity for certain members of their prey? How does the Bdellovibrio penetrate their prey? |
Bdellovibrio are gram negative bacteria that prey upon other gram negative bacteria. They choose young gram negative bacteria to penetrate because young gram negatives are |
· : In dietary studies with mice, it has been found that which bacterial families have contributed to a more lean mouse? |
More Bacteriodetes, less Firmicutes |
Why must there be an extension of Koch's Postulate |
Because there may not be adequate animal hosts available, not all bacteria may be culturable at that particular time, and not all members of a species are equally virulent |
· How does Listeria monocytogenes gain its motility? |
It sequesters actin from host via bacterial protein ACT-A, which simulates the normal host WASP actin binging protein |
What are Kappa particles? |
: Kappa particles are release by paramecium to kill sensitive paramecia and are resistant to its own symbiont but sensitive to others symbiont strains. |
When mice don't have toll-like receptor 5, what would happen to them? |
They would tend to have obesity. |
The Gordon lab group transplanted microbes from human feces into mice bred with no microorganisms in their guts. What were the results of this experiment? |
The mice that had the human microbiota were fed a high fat and high sugar diet, and the other mice were fed on a low fat diet. Compared to the mice fed on a low fat diet, the mice with the human microbiota had a fast change in the population of bacteria that were in their guts, and they had an increase in body fat. |
: In obese states, adipose tissue is under a constant state of metabolic stress, which leads to the activation of the stress and inflammatory response. As a result, what is produced at an increased rate? |
Macrophages |
What happens with Bifidobacteria levels increase in the gut? |
one of these) reduce inflammation, improve glucose tolerance, reduced gut leakiness allowing less LPS to translocate to serum |
What role does LPS play in the weight gain and obesity, and what are the different organs regulated? |
LPS secreted by gut epithelia affect the liver, adipose tissue, muscle, and the hypothalamus to generally cause inflammation and reduce insulin sensitivity, thus increasing the level of glucose circulating in the blood. LPS also causes an increase in LPL (lipoprotein lipase) in adipose tissue and muscle which causes triglyceride accumulation in adipocytes. |
What are the Molecular Koch Postulates? |
•1. The gene or its product should be found in strains of bacteria that cause disease and not in bacteria that are avirulent. •2. A mutation of a virulent gene should reduce its virulence, and conversely, introduction of a virulent gene into an avirulent strain should make it virulent. •3. The gene should be expressed by the bacterium during the infection process. •4. Antibodies to a gene product should be protective, or the gene product should elicit an immune response.
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NSAIDS inhibit what enzyme? |
COX |
What is the role of HGF, MET, and E cadherin? |
Binding activates cellular survival and proliferation signals and induces cytoskeletal rearrangements that function in cellular motility and differentiation. |
How does Listeria monocytogenes escape from the phagosomes? |
Listeria monocytogenes secretes Phospholipases A and B (PlC A/B) and Listeriolysin O (LLO) |
What is the mechanism that Legionella pneumophila uses to prevent being degraded after being ingested (phagocytosis) into the cell? |
The microbe uses mechanisms that cause the host cell to surround the phagosome that contains the microbe with ribosomes, ER proteins and mitochondria. The mechanism takes advantage of the RalF protein as an exchange factor for ARF which is a regulator for the transport of proteins from the ER to the Golgi. The phagosome attracts the cytosol protein RalF which attracts the ARF. The ARF then attracts the ribosomes, ER proteins and mitochondria to surround it. This prevents the lysosome from being able to kill the microbe. |
What bacterial symbiont is part of a unique compound symbiotic association that includes itself, a host bacteria, a bacteriophage? |
Bdellovibrio is a bacterial symbiont that carries out its reproductive cycle in the periplasmic space of a Gram negative host bacteria like E. coli and is dependent on the host for nutrients much like a virus. Bacteriophages specific to Bdellovibrio require Bdellovibrio to be in the E.coli host before starting replication. |
How is the microbiota of obese animals different from that of lean animals? |
A2: obese animals showed a decrease in Bacteroides and increases in Firmicutes and Archaea. |
How has H. pylori evolved to regulate Apoptosis? |
Cag Secretion system forms NF-Kb. It uses by binding to MHC molecules that increases apoptosis. It also has VAC increase mitochondrial release of cytochrome C which leads to activation of Caspase 3 and apoptosis. They can also downregulate apoptosis through inhibition of NFb by prostaglandin formation through COX enzymes. |
What are the two pigments have been found in the skin secretion of the hippopotamus and the color of their skin? |
Hipposudoric acid, which is red, and norhipposudoric acid, which is orange. |
What are Wolbachia bacteria known for? |
: It transmitted from female to offspring, and may cause parthenogenesis, cytoplasmic incompatibility, feminization of offspring, or male killing of offspring.
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CagA is an example of what protein? |
CagA is an example of such a prokaryotic effector protein, translocated by adhered Helicobacter pylori into the host epithelial cell. |
What make CagA unique?
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CagA is unique, however, in that its chronic presence apparently increases the risk of long-term complications for the host, such as the development of peptic ulcers and gastric adenocarcinoma |
What are the 4 mechanisms of phagocytosis? |
Oxygen-dependent phagocytosis, Oxygen-independent phagocytosis, Nitrogen-dependent phagocytosis, and Lactic acid production.
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How is the sponge-cyanobacteria relationship mutualistic? |
Cyanobacteria provide nutrients to sponges, and sponge provides a shelter for bacteria. |
How does Listeria monocytogenes pass from one host cell to another while avoiding the immune system? |
Listeria uses ActA to polymerize actin to produce an "actin tail" that attaches to its old pole and directs its motion in one direction. This actin based motility propels Listeria into the cell membrane, causing the membrane to protrude. This protrusion, the Listeriapod, contacts neighboring cells which phagocytize and engulf the Listeria as a phagosome thereby transferring the Listeria into a new host cell without it being exposed to the extracellular environment where immune cells might detect it. |
Which receptor was studied in mice with regards to obesity, and how did this receptor recognize the presence of bacteria? |
Toll-like Receptor 5 (TLR5); this receptor "senses" bacteria by, for example, recognizing flagella |
What protein does L. moncyogenes appropriate from its host cell to become motile? |
Actin |
How does L. pneumophila inhibits apoptosis? |
by upregulating antiapoptotic genes. |
whats the role of ARF ? |
it regulates the vesicular transport between Golgi and ER. |
An increased level in which bacteria increased weight loss, |
Bacteroides |
What does proinflammatory cytokines lead to? |
It leads to insulin resistance. |
What bacteria spp. produces the effector protein Cytoxin-associated antigen A (CagA) and what are the consequences? |
CagA is injected to the host epithelial cells by adhered H.pylori. It affects the following: Actin Polymerization - cytokines secrtion - regulation of proapoptotic and antiapoptotic genes etc... |
How can Legionella pneumophila exit after replicating in the host cell? |
By producing pore forming toxins that are inserted into the plasma membrane and leading to the osmotic lysis of the cell followed by the release of the intracellular bacteria.
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FcRs induced by what allow immune complexes of HIV to infect fibroblasts? |
CMV |