Types
Not all the species in the gut have been identified because most cannot be cultured, and identification is difficult. Populations of species vary widely among different individuals but stay fairly constant within an individual over time, even though some alterations may occur with changes in lifestyle, diet and age. An effort to better describe the microflora of the gut and other body locations has been initiated; see Human microbiome project. In 2009, scientists from INRA (France) highlighted the existence of a small number of species shared by all individuals constituting the human intestinal microbiota phylogenetic core.
Most bacteria belong to the genera Bacteroides, Clostridium, Fusobacterium, Eubacterium, Ruminococcus, Peptococcus, Peptostreptococcus, and Bifidobacterium. Other genera, such as Escherichia and Lactobacillus, are present to a lesser extent. Species from the genus Bacteroides alone constitute about 30% of all bacteria in the gut, suggesting that this genus is especially important in the functioning of the host.
The currently known genera of fungi of the gut flora include Candida, Saccharomyces, Aspergillus, and Penicillium.
An enterotype is a classification of living organisms based on its bacteriological ecosystem in the human gut microbiome. Three human enterotypes have been discovered.
Read more about this topic: Gut Flora
Famous quotes containing the word types:
“As for types like my own, obscurely motivated by the conviction that our existence was worthless if we didn’t make a turning point of it, we were assigned to the humanities, to poetry, philosophy, painting—the nursery games of humankind, which had to be left behind when the age of science began. The humanities would be called upon to choose a wallpaper for the crypt, as the end drew near.”
—Saul Bellow (b. 1915)
“The rank and file have let their servants become their masters and dictators.... Provision should be made in all union constitutions for the recall of leaders. Big salaries should not be paid. Career hunters should be driven out, as well as leaders who use labor for political ends. These types are menaces to the advancement of labor.”
—Mother Jones (1830–1930)
“If there is nothing new on the earth, still the traveler always has a resource in the skies. They are constantly turning a new page to view. The wind sets the types on this blue ground, and the inquiring may always read a new truth there.”
—Henry David Thoreau (1817–1862)