Exam 3 overview

1. Human microbiome:

What the human microbiome is (and what it isn’t).
Mutualist and commensal relationships in the microbiome dominate over parasitic.

The human microbiome project and the critical importance of our microbiota:
Microbiota has roles in disease (prevention and promotion based on factor produced). Also, nutrient acquisition since they break down complex macromolecules into small things to absorb. Also play a significant role in obesity. Microbiota transplant from both lean and obese humans was transplanted into mice, and even on the same diet, the mice took on the composition of the donor. This is likely due to obese microbiota having a greater ability to recover energy from food.

Also, the vaginal microbiome of pregnant women transforms to a low diversity Lactobacillus-dominated microbiota. If this transformation doesn’t happen, preterm birth may occur, which is the leading fatality in newborns.

How genes within the human gut microbiome are cataloged.
DNA from fecal samples was analyzed and contigs ere mapped, getting rid of redundant, poor quality DNA. Then common genes were found. Then all DNA from the contigs were sequenced using next gen Illumina sequencing. Then sequences were compared to a reference to positively identify.

How the microbiota is established in a newborn
Prenatal: Mothers gut microbiota, vaginal infection, and periodontitis
Birth: C-section or vaginal delivery
Infancy: Breastfeeding, antibiotics (disrupt development of microbiome), host genetics, environment

Usually by age 1-3: the toddler has an adult-like microbiota.

C-section impact: Newborn has higher colonization of hospital pathogens
Vaginal delivery: Newborn has higher colonization of good Bacteroides
Antibiotics: bad for developing microbiota as it causes disruptions
Breastmilk: Contains carbohydrates that feed microbiome; contains small amount of bacteria

Burkina Faso (rural village) toddlers: Diet high in fiber and carbs, low in animal protein —> lower rate of obesity. They have increased Bacteroidetes and lower Firmicutes. This is likely because bacteria coevolved with the polysaccharide-rich diet in BF, maximizing energy intake from plant fibers

European toddlers: Higher in animal fat and protein, lower in fiber. Associated with increased obesity with opposite bacteria present.

2. Fecal Transplants

   Fecal transplants: what they are and how they can be used to treat C. difficile infections

   Transplanting microbiota of healthy person to sick person. Can be used to treta c diff due to colonization (c. diff cannot colonize in presence of healthy transplant). Also FMTs will produce becteriocins which are toxic to c.diff.
   

   microbial colonization in fecal transplants can be tracked
   ONly a subset of donor species will be engrafted into recipient.

   you don’t have to stop at fecal transplants
   

   Probiotics: what they are

   insights into whether they are helpful following antibiotic use

   their relationship with antibiotic resistance genes

   that “designer probiotics” are the future