Microbial Symbioses with Humans (Lec 17)

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Questions and Answers

Which term is used to describe all the microbes in a microhabitat?

Microbial symbiosis

Microbiota (correct)

Operational taxonomic unit

Microbiome

What is the approximate number of microbes in the human microbiome?

10^3

10^13 (correct)

100

Which body site will have very different microbes than the mouth?

Gastrointestinal tract

Oral cavity

Urogenital tract

Skin (correct)

What does OTU stand for in the context of microbiomes?

Operational taxonomic unit Signup and view all the answers

What is the term used to describe a functional collection of different microbes in a particular environmental system?

Microbiome Signup and view all the answers

What are some potential future benefits of knowing the human microbiome?

All of the above Signup and view all the answers

What is the term used to describe closely related individuals based on DNA sequence comparisons?

Operational taxonomic unit Signup and view all the answers

Which of the following statements is true about the microbiota in obese mice?

Obese mice have more Firmicutes and methanogens than non-obese mice. Signup and view all the answers

What is the main finding of the study on the shared salivary microbiota among couples?

The microbiota on the dorsal surface of the tongue is more similar among partners than unrelated individuals. Signup and view all the answers

What is the effect of transferring microbiota from an obese human twin to germ-free mice?

The mice become obese. Signup and view all the answers

Which genus is the most abundant in the oral microbiota?

Firmicutes Signup and view all the answers

What is the main implication of maternal infection for autism spectrum disorder and schizophrenia?

It is a risk factor. Signup and view all the answers

What is the main finding about the gut-brain axis and its influence on behavior?

Gut microbiota can influence behavior, particularly autism-like behaviors. Signup and view all the answers

What is the effect of giving normal mouse microbiota to germ-free mice?

The mouse will gain a little weight Signup and view all the answers

What is the most abundant single species in the oral microbiota?

Veillonella parvula Signup and view all the answers

What is the main conclusion of the study on the shared salivary microbiota among couples?

A shared salivary microbiota requires frequent and recent bacterial exchange. Signup and view all the answers

What is the function of the gastrointestinal (GI) tract in humans?

Responsible for digestion of food, absorption of nutrients, and production of nutrients by the indigenous microbial flora. Signup and view all the answers

Which of the following is true about the microbial populations in the stomach and small intestine?

Helicobacter pylori is found in ~50 percent of the world's population. Signup and view all the answers

Which bacterial phyla make up the majority of the human gut microbiota?

Firmicutes, Bacteroidetes, and Proteobacteria Signup and view all the answers

What are the three basic enterotypes currently being studied in relation to the gut microbiota?

Bacteroides, Prevotella, and Ruminococcus. Signup and view all the answers

What is the main factor driving the composition of gut microbiomes?

Dietary factors. Signup and view all the answers

What is the role of mouse models in studying the gut microbiota?

To study the effects of a germ-free environment on the gut microbiota. Signup and view all the answers

What is the balance between metabolically healthy microbiota and dysbiosis crucial for?

Regulating metabolism and preventing obesity. Signup and view all the answers

The human body contains more microbes then own cells.

True Signup and view all the answers

When does colonization of the human body begin?

at birth Signup and view all the answers

in some individuals, the stomach microbes can cause ulcers, which microbe is responsible?

helicobacter pylori Signup and view all the answers

Which of the following dose NOT normally contain microflora in a health individual?

Urethra Signup and view all the answers

What bacterium causes feet to stink?

Methionine lyase Signup and view all the answers

What is the process of Methionine lyase in creating a smell-like cheese? most correct

methionine is converted into methanethiol, ketobutorate and NH4+ Signup and view all the answers

What are the neutralizing agents produced by H.pylori for there ability to live within the mucus layer of the stomach?

ammonium and Bicard Signup and view all the answers

What is the bacteria most pro-dominate in meat-eating individuals compared to non-meat-eating individuals?

Bactericides os the most abundant in meat-eaters Signup and view all the answers

What are the three most predominant phyla in the gut microbiota?

Firmicutes, Ruminicoccus, Bacteriodes Signup and view all the answers

In the mouse model of an obese mouse compared to a lean mouse which bacteria are more pro-dominant in the lean mouse?

Higher levels of Bacteroidetes Signup and view all the answers

Study Notes

Microbiome Terminology

The term used to describe all the microbes in a microhabitat is microbiome.
OTU stands for Operational Taxonomic Unit in the context of microbiomes.

Human Microbiome

The approximate number of microbes in the human microbiome is 10^14.
The human body contains more microbes than its own cells.
Colonization of the human body begins at birth.

Site-Specific Microbes

The mouth and gut have different microbiomes.
The stomach and small intestine have different microbial populations.

Microbiome Function and Influence

A functional collection of different microbes in a particular environmental system is called a microbiota.
The balance between metabolically healthy microbiota and dysbiosis is crucial for human health.
The gut-brain axis influences behavior.
The gastrointestinal (GI) tract is responsible for digestion and absorption of nutrients in humans.

Gut Microbiota

The majority of the human gut microbiota is composed of Firmicutes, Bacteroidetes, and Actinobacteria phyla.
The three basic enterotypes being studied in relation to the gut microbiota are driven by the composition of gut microbiomes.
Mouse models are used to study the gut microbiota.

Microbiome in Health and Disease

In obese mice, the microbiota is different from that of lean mice.
Transferring microbiota from an obese human twin to germ-free mice results in the recipients becoming obese.
Maternal infection is implicated in autism spectrum disorder and schizophrenia.
Helicobacter pylori is responsible for stomach ulcers in some individuals.

Microbiome Composition

The most abundant genus in the oral microbiota is Streptococcus.
The most abundant single species in the oral microbiota is Streptococcus sanguis.
The bacterium responsible for making feet stink is Brevibacterium.
Methionine lyase is involved in the process of creating a smell-like cheese.

Specific Microbiota

Helicobacter pylori produces neutralizing agents to live within the mucus layer of the stomach.
The bacterium most predominant in meat-eating individuals compared to non-meat-eating individuals is Bacteroidetes.
In the lean mouse, Bacteroidetes are more predominant compared to the obese mouse.

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Description

Test your knowledge on microbial symbioses with humans in this quiz. Learn about the microbiome, microbiota, and the different types of interactions between microorganisms and the human body.