Micro

Gut microbiota

The community of microorganisms that reside in the gut, playing a crucial role in health and disease.

Germ-free mice

Mice raised in a sterile environment to study specific bacterial colonization.

C-section vs. Vaginal birth

Infants born through C-section have different microbiomes compared to those born vaginally, which are more similar to the mother's.

Commensal bacteria

Non-pathogenic bacteria that live in the gut and are beneficial to host health.

Adaptive immune response

The immune response that improves upon repeated exposure to a pathogen and is influenced by gut microbiota.

Obesity's relation to gut microbiota

Obesity has been linked to differences in gut microbiota composition between normal and genetically obese mice.

Skin microbiota

The diverse community of bacteria residing on the skin, with approximately 1 million bacteria per square centimeter.

Quorum sensing

Communication process in bacteria that uses autoinducers to coordinate behavior based on population density.

Exotoxins

Toxins secreted by pathogens that can harm host cells or tissues.

Endotoxins

Components of the outer membrane of Gram-negative bacteria that can induce inflammation.

Infection

The colonization of a host by a pathogen, which can lead to disease.

Virulence factors

Molecules that enhance the ability of a pathogen to cause disease.

Attenuation

The decrease or loss of virulence in a pathogen.

Adhesins

Molecules that enable bacteria to adhere to host cells.

Invasins

Surface molecules that facilitate the penetration of host cells or tissues.

Toxigenicity

The ability of a pathogen to produce toxins.

Superantigens

A class of antigens that cause excessive activation of T cells and a strong immune response.

Cytolytic exotoxins

Exotoxins that disrupt cell membranes leading to cell lysis and death.

Invasiveness

The ability of a pathogen to penetrate host tissues and colonize.

Extracellular matrix (ECM)

The network of proteins and molecules in tissues that supports cell adhesion and migration.

IgA protease

An enzyme produced by pathogens that degrades IgA antibodies, weakening immune defense on mucosal surfaces.

Microbiome

A functional collection of different microbes in a particular environmental system.

Human microbiome diversity

Different human microbiome sites are diverse in families of bacteria present and similar in major metabolic pathways expressed.

Gut microbiome location

Most of the gut microbiome is present in the colon and contains mostly anaerobic bacteria.

Initial colonization of the microbiome

Initial colonization of the microbiome occurs at birth.

Skin microbiota function

Bacteria that break down fats for energy are found in sebaceous areas of the skin, such as Propionibacterium.

Role of microbes in herbivores

Microbes in herbivore animals break down cellulose, hemicellulose, and lignin into glucose, which are then fermented into volatile fatty acids (VFAs).

Pathogenicity

The ability of an organism to cause harm to its host.

Virulence

The degree to which harm is inflicted on the host by a pathogen.

E. coli strain differences

Different strains of E. coli are able to induce different types of disease due to their virulence factors.

Secretion Systems

Proteins that can inject toxins into host cells.

Pathogenicity Islands

Segments of DNA that contain virulence factors.

Colonization in infection

Colonization is the step of infection where bacteria multiply, thus establishing an infection.

First Step of Root Nodule Formation

Recognition + attachment of rhizobacteria to root hair for specificity

Second Step of Root Nodule Formation

Rhizobacteria secrete Nod factors, triggering overall nodule formation

Third Step of Root Nodule Formation

Bacterium Invasion of root hair

Fourth Step of Root Nodule Formation

1. creation of infection thread by plant

2. travel to main root via infection thread

Fifth Step of Root Nodule Formation

1. Rhizobacteria become modified bacteria called Bacteroides

2. Colonization → bacteria replication and establish an infection

What are herbivores poor at digesting, and require microbacteria for?

cellulose and hemicellulose

What kind of relationship do herbivores have with the bacteria that break down cellulose?

Mutualistic

Prebiotics

typically carbohydrates that are indigestible by human hosts, but provide nutrition for fermentative gut bacteria

Probiotics

 live organisms that confer a health benefit to the host

Synbiotics

Some probiotic formulations (such as certain yogurts) contain prebiotics as well to supply both beneficial aspects in a single treatment.