Chapter 13 Part 1

Question 1

What does the term holobiont mean?

Answer 1

A human plus all of its resident microbiota

Question 2

What are the Various types of symbiotic microbes found in humans?

Answer 2

Bacteria
Archaea
Fungi
Viruses
Mites
Protozoa

Question 3

What are the common terms for the symbiotic microbes found in humans?

Answer 3

Natural biota
Natural flora
Resident biota
Human microbiome

Question 4

What are two of the biggest reasons microbiology is rapidly changing?

Answer 4

Technology and Awareness

Question 5

What are the biggest factors in the change of technology?

Answer 5

Vast improvements in DNA sequencing coupled with improvements in computer technologies.

Significant reductions in the cost

Question 6

What was the primary focus, on the study of microbes, during the 1800s and 1900s?

Answer 6

From the late 1800s and throughout the 1900s Doctors, microbiologists, pathologists, virologists, epidemiologists, and more spent decades culturing microbes found on the human body and studying pathogens isolated from the sick and dying.

The made enormous progress in pathology, saved countless lives, and ushered in a new era called “The Golden Age of Microbiology”

Question 7

What was the previous belief on the ratio of microbes to human cells?

Answer 7

10:1

Question 8

What is the ratio of between human cells and microbes believed to be currently?

Answer 8

1:1

Question 9

What is the HMP?

Answer 9

The Human Microbiome Project

Question 10

What are the goals of the HMP?

Answer 10

1) Collect genetic sequences from microbes on the human body
2) Determine which microbes are present on the human body
3) Determine what role these microbes play in health and disease

Question 11

How many protein encoding genes are found in human cells?

Answer 11

22,000

Question 12

How many encoding genes are in the microbiome?

Answer 12

8 million

Question 13

How many more encoding genes are there more of in the microbiome compared to human genome?

Answer 13

300x

Question 14

Results from the HMP

Answer 14

1) human cells contain approximately 22,000 protein-encoding genes
2) microbes are now being recognized to exist in body locations previously thought to be sterile
3) all healthy people harbor potentially dangerous pathogens in low numbers
4) vast quantities of viruses are found in healthy individuals
5) gut bacteria may influence your overall health

Question 15

Why are most microbes unable to colonize the human body?

Answer 15

Most microbes are removed or destroyed by the host’s defenses long before colonization

Question 16

How much does the normal biota differ in subjects studied, according to the HMP?

Answer 16

It varies significantly

Question 17

What remains constant per subject studied?

Answer 17

Protein profiles remain constant

Question 18

What is microbial antagonism?

Answer 18

The inhibitory effect that normal biota have on other “invading” microbes

Question 19

What are the two mechanisms by which microbial antagonism works?

Answer 19

1) Blocking body sites that could be established by invaders

2) Releasing chemicals that are harmful to invading microbes

Question 20

Explain how the “normal biota” May become harmful

Answer 20

They can actually be harmful in large numbers

Question 21

How does the microbiota differ in babies born via natural birth vs cesarean section?

Answer 21

Vaginal births provide higher levels of natural Bifidobacterium

Cesarean sections tend to provide more bacteria from the skin

Question 22

What are the potential consequences of the mode of birth?

Answer 22

Natural births expose babies to the natural microbes our bodies are accustomed to, “correctly shaping” the immune system

Cesarean sections appear to do the opposite, exposing the developing immune system to microbes that trigger inappropriate immune development

Question 23

What are the means of normalizing the post-cesarean gut microbiota according to Dr. Mark Sloan?

Answer 23

1) Probiotics- administering healthful probiotic bacteria to correct an imbalanced microbiota
2) Direct Transfer if Maternal Secretions- placing maternal vaginal and rectal material into the newborn’s mouth
3) Fecal transplantation- direct transfer of fecal material from healthy adults