BI 305 Exam 5 Chp 23, Tiny Earth, and Beer 101 Flashcards
Risks of Microbiomes
Opportunistic pathogens if some species get in the wrong place.
Benefits of Microbiomes
Stimulate the immune system.
Provide competition for pathogens.
Produce antibiotics and antibacterial peptides to fight against competition.
The gut microbiome communicates with peptides to the brain.
Send signals such as feeling satiated.
The gut microbiome generates short-chain fatty acids for human host cells to digest.
Provide nutrition, vitamins, and degrade materials that we cannot do on our own.
Importance of Microbiomes
The microbiome plays a role in obesity, allergies, liver disease, GI syndromes, and possibly even psychiatric disorders as the gut microbiome can influence the brain.
Skin Microbiome
More acidic pH=4-6.
More Gram-positive organisms live there.
Lots of lysozyme on the skin.
Acne can be caused by a bacterial infection.
Eye Microbiome
Bathed in antimicrobial lysozyme.
Only a few bacteria can live there.
Streptococcus pneumoniae and other bacteria can cause infection.
Ex: Pink eye.
Oral and Nasal Cavity Microbiome
Organisms can attach to teeth and eat at the enamel to cause cavities.
Bacteria also live in several areas of the nose, mouth, and throat and can cause infections.
Respiratory tract Microbiome
Uses the mucociliary elevator to make sure most bacteria are moved to the stomach to be degraded and so they don’t habitat the esophagus.
When this fails, you can end up with a cold or respiratory infection.
Stomach Microbiome
Low pH kills most bacteria.
Most notably Heliobacter pylori can inhabit the stomach mucous and increase the pH around it by secreting the urease enzyme.
Intestine Microbiome
Higher pH of 8 due to base secreted by the pancreas to neutralize stomach acid.
Changes in the intestinal microbiome can lead to infections (ex: Clostridium difficile) or lead to disorders such as Crohn’s and UC.
Genitourinary tract Microbiome
The urinary tract is considered sterile unless there is an infection causing a UTI.
Vagina has its own microbiome.
What is the SCFA acetate associated with?
Acetate is thought to increase obesity because it promotes inflammation, and is used for lipid synthesis.
How are microbiomes associated with obesity?
Gnotobiotic mice, mice without a microbiome, were tested.
If they got an obese fecal transplant, they gained weight.
Did not occur if they got a lean fecal transplant.
When housed together, the obese mouse started to resemble the lean mouse.
The reverse was not found.
SCFAs proportions are linked with obesity.
What is the SCFA butyrate associated with?
Butyrate is thought to decrease obesity because it inhibits inflammation, and stimulates the production of hormones that limits hunger.
What is the SCFA propionate associated with?
Propionate is thought to affect weight either way because it increases inflammation but also diverts fatty acids away from cholesterol synthesis.
Also stimulates the production of hormones to limit hunger.
What are the characteristics of the innate immune system?
No priming. Second defense after physical barriers such as skin and mucous membranes. Acts quickly. Non-specific. Responds by detection and elimination.
What are the characteristics of the adaptive immune system?
Needs priming. Slow defense. Specific Contains memory for certain pathogens by generating antibodies. Cells are not phagocytic.
What are Hematopoietic stem cells?
Hematopoietic stem cells are the precursor bone marrow cells.
They divide into myeloid stem cells and lymphoid stem cells that are still in the bone.
What are myeloid stem cells?
Myeloid stem cells differentiate into cells from the innate immune system.
What are mast cells?
High-affinity receptors for IgE, which are associated with allergic responses.
Mast cells are similar to basophils in structure but it is found in the mucosa and connective tissue.
Stationary residents in those areas.
What are myeloblast cells and what do they differentiate into?
Innate immune system cell.
Differentiates into eosinophils, basophils, and neutrophils.
What are eosinophils?
Produce toxic proteins to destroy microbes and release vasoactive agents.
Important for killing multicellular parasites like helminth worms.
What are basophils?
Produce toxic proteins to destroy microbes and release vasoactive agents.
High-affinity receptors for IgE, which is associated with allergic responses.
What are neutrophils?
Highly phagocytic. Catch bacteria in neutrophil extracellular traps (NETs). Is a spew lattice of DNA. Has anti-microbial properties. Dominant in early stages of infection.
What are monoblasts and what do they divide into?
Innate immune cells.
Divide into monocytes which divide into dendritic cells and macrophages.
What are dendritic cells?
Abundant in the epidermis of the skin, mucous membranes, thymus, and lymph nodes.
Phagocytic.
Activate adaptive immunity responses.
Antigen-presenting cells (APCs) for T cells.
What are macrophages?
Dominant in later stages of infection.
Purposes:
The first defense is innate immunity.
Antigen-presenting cells (APCs) for T cells.
What are lymphoid stem cells?
Differentiate into adaptive immune cells.
What NK cells?
NK cells kill infected host proteins who present abnormal MHC proteins by inserting toxic granzymes.
How do NK cells kill host cells?
NK cells release perforin (perforates membrane (makes a hole in the membrane)) and granzymes (proteases causing apoptosis).
NK releases granzymes to go through the hole.
What are granzymes?
From NK cells.
Granzymes are cytotoxic and convince the cell to undergo apoptosis.
Kills intracellular pathogens as well.
Granzymes damage mitochondria so cytochromes are released.
Released cytochromes activate systolic host proteases called caspases (cysteine-dependent aspartate-directed proteases) that degrade a lot of macromolecules and structures in the cell.
Why do NK cells not want to lyze the host cell?
That would release the microbes inside it.
What is anti-body-dependent cell-mediated cytotoxicity (ADCC)?
For NK cells.
NK cells can bind to the Fc region of an antibody, so when they bind to a host cell surrounded by antibodies, they kill the infected host cells.
What are T cells?
T-cells (lymphocytes) bind to these APCs and stimulate antibody production and cytotoxic cells to kill host infected cells.
Why is the beer-making process so intensive?
The process is very intensive due to having to make sure everything is sanitized.
Also, the temperature and pH have to be carefully controlled to get the right amount of sugar released that yeast can metabolize.
What is malting?
Malting=allowing grain to germinate.