What is archaea in simple words?

What do archaea do to humans?

The current picture, based on experimental studies, shows a limited range of interaction.

We discuss here a new idea and set of experiments that could shed new light on the subject. In some circumstances, the archaeal cells could have different biological processes or mechanisms that allow them to exploit their host differently. Archaeal proteins of bacterial origin could be used as a first level of the interaction, and some of the enzymes associated to these proteins could modify or hydrolyze host substrates involved in signaling pathways. These processes could modulate important pathways of the microbe-host. Here we describe what happens in this scenario and how it could be implemented in the context of the gut microflora. At the same time, with the increase in our understanding, it seems there are also more questions to be answered. The major characteristics between archaeal cells (A) and those of bacteria (B) are: (i) archaeal cells do not contain nuclei, (ii) they lack peptidoglycan, and (iii) they are anaerobic. So, what is the role of archaeal cells in animals? Is there something special about them and why they have been selected to coexist with an organism? What has happened in history? Archaea entered the eukaryotic evolutionary scale because organisms living in extreme conditions or with few nutrient sources were adapted for survival. Nevertheless, archaea are not parasites of our life.

What is archaea in simple words?

Archaea is one of the five domains of the three domains of the archaea group.

As per the knowledge so far about archaea, they are single-celled prokaryotic organisms that belong to the superphylum of domain Bacteria. They live in environments with very low or no oxygen, have genomes characterized by relatively simple organization, and are found in a diverse array of habitats ranging from hot springs and boiling vents to ancient marine sediments. Because most are aerobes, some are free-living and others live symbiotically in both aerobic and anaerobic environments. However, they lack a conventional plasma membrane and contain a cell wall comprising several layers and a large complex capsule or coat. These components, together with a narrow cytoplasmic membrane, resemble those of Gram-positive bacteria. Since the archaeon cell wall appears unique among the prokaryotes, some researchers have proposed a third domain in the domain classification, 'archaea' for archaeon, thus reducing the number of domains from three to two (Bacteria and Archaea). Some groups of archaea are more closely related to eukaryotes than to bacteria and their phylogenetic history is also well resolved with eukaryotic characters. Unlike most bacteria, archaea lack the metabolic apparatus to produce DNA-directed RNA polymerase. Despite the similarities, they have many unique features, including high temperature adaptations.

Archaea has a unique cell structure. Archaea possess a cell wall rather than a cell membrane. They are spherical or ovoid cells that vary in size from 0.1 to 3 m in diameter. The genome contains a single circular chromosome composed of one kind of molecules. The DNA in the cells of archaea is condensed, forming large nucleoids (DNA 'clumps') surrounded by abundant small structures called chromatin. The nucleus, which is enclosed in a membrane, is relatively spacious and it does not divide during the cell cycle.

The archaeal genome typically lacks many genes involved in the metabolism of nucleic acids, proteins and polysaccharides. Most genes are arranged in a compact manner on the chromosomal DNMost of the other genes encode proteins, while enzymes have been identified only in a few species.