Chapter 13 Part 1 Flashcards
What does the term holobiont mean?
A human plus all of its resident microbiota
What are the Various types of symbiotic microbes found in humans?
Bacteria Archaea Fungi Viruses Mites Protozoa
What are the common terms for the symbiotic microbes found in humans?
Natural biota
Natural flora
Resident biota
Human microbiome
What are two of the biggest reasons microbiology is rapidly changing?
Technology and Awareness
What are the biggest factors in the change of technology?
Vast improvements in DNA sequencing coupled with improvements in computer technologies.
Significant reductions in the cost
What was the primary focus, on the study of microbes, during the 1800s and 1900s?
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”
What was the previous belief on the ratio of microbes to human cells?
10:1
What is the ratio of between human cells and microbes believed to be currently?
1:1
What is the HMP?
The Human Microbiome Project
What are the goals of the HMP?
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
How many protein encoding genes are found in human cells?
22,000
How many encoding genes are in the microbiome?
8 million
How many more encoding genes are there more of in the microbiome compared to human genome?
300x
Results from the HMP
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
Why are most microbes unable to colonize the human body?
Most microbes are removed or destroyed by the host’s defenses long before colonization
How much does the normal biota differ in subjects studied, according to the HMP?
It varies significantly
What remains constant per subject studied?
Protein profiles remain constant
What is microbial antagonism?
The inhibitory effect that normal biota have on other “invading” microbes
What are the two mechanisms by which microbial antagonism works?
1) Blocking body sites that could be established by invaders
2) Releasing chemicals that are harmful to invading microbes
Explain how the “normal biota” May become harmful
They can actually be harmful in large numbers
How does the microbiota differ in babies born via natural birth vs cesarean section?
Vaginal births provide higher levels of natural Bifidobacterium
Cesarean sections tend to provide more bacteria from the skin
What are the potential consequences of the mode of birth?
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
What are the means of normalizing the post-cesarean gut microbiota according to Dr. Mark Sloan?
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
