Human Microbiome Metagenomics Quiz

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Questions and Answers

What is the primary purpose of metagenomics techniques?

To sequence all genomic DNA present in a sample (correct)

Identify different types of microbes on human skin

Enhance the immune response in humans

Determine antibiotic resistance in microbial communities

Which microbial phyla predominantly inhabit the skin according to the classification mentioned?

Firmicutes

Bacteroidetes

Lactobacillus

Actinobacteria (correct)

What is inferred about metabolic activities based on metagenomics?

They can be inferred from the genes present. (correct)

Only microbial diversity can be observed.

No relation exists between genes and metabolic activities.

Metabolic activities cannot be accurately determined.

How do microbial communities differ across body habitats?

Microbial communities vary by specific body sites. Signup and view all the answers

What is the significance of removing human sequences in metagenomics?

To focus on microbial diversity from environmental samples. Signup and view all the answers

Which bacteria predominate in the gut according to the described microbial distribution?

Bacteroidetes and Firmicutes Signup and view all the answers

What is one of the key questions addressed in the study of the human microbiome?

Where do these microbes originate? Signup and view all the answers

Which of the following statements best describes the change in microbial communities over time?

They can undergo modifications based on environmental factors. Signup and view all the answers

What is the primary function of Lactobacillus in the vaginal microbiome?

To produce lactic acid and maintain low pH Signup and view all the answers

Which statement about the gut microbiome is correct?

It predominantly contains the phyla Bacteroidetes and Firmicutes. Signup and view all the answers

Which bacterial family is reduced due to circumcision in the penis microbiome?

Clostridia Signup and view all the answers

What is a common feature of the oral cavity microbiome when teeth are present?

Dominated by anaerobic bacteria between teeth and in gums Signup and view all the answers

What role do the metabolic by-products of skin bacteria play?

Causing body odor through volatile fatty acids Signup and view all the answers

How do delivery methods influence microbiome acquisition?

C-section delivery reduces exposure to beneficial bacteria from the mother. Signup and view all the answers

In which environment are most skin bacteria found?

Anaerobic environments Signup and view all the answers

Which group of bacteria is predominantly associated with tooth decay?

Anaerobes Signup and view all the answers

What factors can alter the colonization succession of the gut microbiome in the first three years of life?

Type of milk and exposure to animals Signup and view all the answers

What type of life changes can lead to modifications in the microbiome?

Transition to solid food and travel Signup and view all the answers

What is observed in the dynamics of daily activity measurements in the small cohort studied?

The measurements reach an asymptote over time Signup and view all the answers

Over one year, what percentage of Subject A’s saliva microbiota samples contained the identified core operational taxonomic units (OTUs)?

95% Signup and view all the answers

What percentage of total counted bacteria does the small subset of highly abundant core taxa represent during stable periods?

99.7% Signup and view all the answers

What method was primarily used to measure the dynamics of gut and oral microbial communities?

Daily collection of stool and saliva samples Signup and view all the answers

During stable periods, what are the core OTUs characteristic of?

A small minority of the sampled microbiome Signup and view all the answers

How does exposure to antibiotics affect the gut microbiome during early life?

It can alter the colonization succession of the microbiome Signup and view all the answers

What is the process used to obtain real axenic mice?

Hysterectomy rederivation Signup and view all the answers

What does the term 'gnotobiotic' mean?

Known life with all microbes identified Signup and view all the answers

What percentage of shared bacterial species exists between axenic mice and regular mice?

30% Signup and view all the answers

What is the relationship between humans and their microbiota described as?

Holobionts Signup and view all the answers

What is one of the major questions in studying the human microbiome?

How the microbiome changes over time Signup and view all the answers

What event does the study titled 'The active human gut microbiota and its phage regulators in health and disease' aim to explore?

The role of gut microbiota in human health and disease Signup and view all the answers

What is indicated as a task for participants in the microbiome study?

Provide a stool sample and dietary questionnaire Signup and view all the answers

Which of the following is NOT a role of microbial cells in human health mentioned?

Increasing human longevity Signup and view all the answers

What is the primary focus of the study regarding infant health?

The development of the baby’s microbiome in various body habitats Signup and view all the answers

Which microorganisms are established first in the infant's microbiome?

Bifidobacteria and facultative anaerobes Signup and view all the answers

What is the predominant type of bacteria in an infant's microbiome after six months?

Obligate anaerobes Signup and view all the answers

What demographic did the study involve for analyzing microbiome development?

Amerindian mothers from rural communities Signup and view all the answers

What is a key method of data collection in this study?

Sampling of biological materials from participants Signup and view all the answers

What type of ethical approval was required for the study?

Institutional Review Board approval for sampling protocols Signup and view all the answers

At what age does the infant's microbiota transition to resemble adult-like microbiota?

At three years Signup and view all the answers

What aspect of cesarean delivery is implied to have an impact on the microbiome according to the study?

It causes a delay in the establishment of beneficial microbes Signup and view all the answers

What constitutes the human microbiome?

Eukaryotes, bacteria, archaeabacteria, viruses, and parasites. Signup and view all the answers

What is the relative number of human cells compared to microbiota cells in the human body?

Human cells are more than microbiota cells by a ratio of about 1:10. Signup and view all the answers

What does the term 'holobiome' refer to?

The combined genomes of humans and their associated microbiome. Signup and view all the answers

Which option is NOT an important question regarding the human microbiome?

How do they communicate with animals? Signup and view all the answers

What is the approximate weight of microbiota in humans?

0.2 kg. Signup and view all the answers

How many genes does the human microbiome consist of approximately?

23,000,000 genes. Signup and view all the answers

Why is it important to study the human microbiome?

To understand its effects on health and diseases. Signup and view all the answers

Which population in the human body does NOT include the microbiome?

Blood. Signup and view all the answers

What has driven the 'microbiome revolution' in research?

The increasing acknowledgment of the microbiome's importance. Signup and view all the answers

What is true about the evolution of research into the microbiome?

Research publications have surged significantly in recent decades. Signup and view all the answers

What role do microorganisms play in human health?

They can influence drug toxicity, like Tylenol. Signup and view all the answers

What is a key characteristic of symbiosis in the human microbiome?

Interactions can fall anywhere on the symbiosis spectrum. Signup and view all the answers

Which of the following statements about human genome and microbiome is correct?

The microbiome generates genes that provide functions that humans cannot. Signup and view all the answers

What type of studies are crucial for translating findings from animal models to humans regarding the microbiome?

Studies comparing microbiomics in both animals and humans. Signup and view all the answers

Study Notes

The Human Microbiome

The human microbiome is a complex ecosystem of microbes residing on and within the human body.
Humans are comprised of eukaryotes, bacteria, archaeabacteria, viruses, and parasites.
Human cells number approximately 10¹³, while the microbiota (cells) is estimated at 1-3x10¹³.
The human genome has approximately 20,000-25,000 genes. The microbiome has approximately 23,000,000 genes.
The weight of the microbiota is approximately 0.2 kg compared to a total body weight of 70kg.

Studying the Microbiome

Traditionally, culture-based methods were used to study the microbiome. Most bacterial cells are not easily cultured using current methods leading to the "Great Plate Count Anomaly".
Culture-independent methods are now used. These methods include 16S rDNA sequencing to identify species.
Deep genomic sequencing, or metagenomics, reveals the genes present. Metagenomics lets us infer metabolic activities.
mRNA sequencing (metatranscriptomics) reveals which genes are actively expressed, and therefore, metabolic activities.
Metabolomics studies the metabolites produced by the microbiome.

Microbial Communities

Microbial communities are highly site-specific.
Different body sites have different dominant bacterial phyla.
Examples include the skin, vagina, gut, and oral cavity, each with distinct microbial populations.

How Do We Acquire A Microbiome?

The fetus was previously considered sterile before birth.
A large number of microbes are acquired after birth.
Colonization patterns vary with delivery method (vaginal vs. C-section).

Microbiome Changes Over Time

The first three years of life are characterized by significant microbiome shifts.
Factors influencing the microbiome include:
the type of feeding (breast milk vs. formula)
the environment
exposures such as pets, antibiotics, and travel
lifestyle changes such as transitions to solid food.
Microbiomes tend to stabilize into adult-like profiles by age three, and change further continuously following life events.

How To Establish Causation/Interventions

In vitro, animal, and human studies help establish causation.
Each model has certain limitations.

Models Used To Study The Microbiome

Mouse models offer controlled conditions to study the microbiome and the effect of various variables.
Germ-free mice (axenic mice) are useful as control models.
Gnotobiotic mice are increasingly used by introducing specific microbes into germ-free mice.

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Description

Test your knowledge on the key concepts of metagenomics as they relate to the human microbiome. This quiz covers topics such as microbial diversity, metabolic activities, and the importance of specific microbial communities in different body habitats. Dive into the fascinating world of microbial interactions and their implications for health.