Prokaryotes ( Latin Procaryota , from ancient Greek πρό 'before' and κάρυον 'core'), or pre - nuclear - single-celled living organisms that do not (unlike eukaryotes ) have an established cell nucleus and other internal membrane organoids (such as mitochondria or the endoplasmic reticulum , with the exception of flat cisterns in photosynthesizing species, for example, in cyanobacteria ).
Paraphyletic group of organisms | |
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Prokaryotes | |
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Legacy taxonomic | |
Scientific name | |
Procaryota | |
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Naddomen Biota Domain: Prokaryotes | |
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Prokaryotes do not develop or differentiate into multicellular forms. Some bacteria grow as fibers or cell masses, but each cell in a colony is the same and capable of independent living.
In terms of biomass and number of species, prokaryotes are the most representative form of life on Earth. For example, prokaryotes in the sea account for 90% of the total weight of all organisms and more than 10 billion bacterial cells in one gram of fertile soil. About 3000 species of bacteria and archaea are known, but this number is probably less than 1% of all existing species in nature.
Classification
The name “prokaryotes” (prokaryotes) was proposed by Edward Shutton in 1925. However, in the taxonomic sense, Shatton did not define this term, that is, he did not make a taxonomic diagnosis. Despite this, in biological classifications, the proposed division of organisms into prokaryotic and eukaryotic remained until the 1990s.
Most prokaryotic cells are very small compared to eukaryotic cells. A typical bacterial cell has a size of about 1 micron , while eukaryotic cells have a large size of 10 to 100 microns. A typical prokaryotic cell is about the same size as a eukaryotic mitochondria.
This set of characteristics distinguishes them from eukaryotes (nuclear organisms), which have cell nuclei and can be both unicellular and multicellular. The difference between the structure of prokaryotes and eukaryotes is the largest among the groups of organisms. Most prokaryotes are bacteria , and these two terms were previously considered synonymous. However, the American scientist Karl Wöse proposed the separation of prokaryotes into bacteria and archaea (Bacteria and Archaea, first Eubacteria and Archaebacteria) through significant genetic differences between these groups. The system of separation of eukaryotes, bacteria and archaea is now considered recognized and is called the System of Three Domains .
For most of the 20th century, prokaryotes were considered as a single group and classified according to biochemical, morphological, and metabolic characteristics. For example, microbiologists tried to classify microorganisms depending on the shape of cells, the details of the structure of the cell wall and the substances consumed by microorganisms [1] . In 1965, it was proposed to establish the degree of kinship of different prokaryotes based on the similarity of the structure of their genes [2] . This approach, phylogenetics , is nowadays essential. At the end of the 20th century, molecular studies provided key information for understanding the evolutionary past of prokaryotes and proved the paraphyletic nature of this group of organisms. It turned out that the archaea , discovered in the 1970s, are as far from bacteria as they are from eukaryotes, and in some respects even closer to the latter (see Intron ).
Characteristic of archaea and bacteria | Peculiar to archaea and eukaryotes | Peculiar only to the archaea |
---|---|---|
No decorated nucleus and membrane organelles | No peptidoglycan (murein) | Cell wall structure (for example, some archaeal cell walls contain pseudomorein ) |
Ring chromosome | DNA linked to histones [3] [4] | Lipids containing a simple ether linkage are present in the cell membrane. |
Genes are combined into operons | Broadcast starts with methionine [5] | Flagellin structure [6] |
Similar RNA polymerase , promoters and other components of the transcriptional complex, are introns and RNA processing [6] [7] [8] | The structure of the ribosome (some signs are brought closer to the bacteria, some - with eukaryotes) | |
Polycistronic mRNA | Similar DNA replication and repair [9] | Structure and metabolism of tRNA [6] [10] |
Cell size is several orders of magnitude smaller than that of eukaryotes | Similar ATPase (type V) |
Initially, bacteria and cyanobacteria, considered as separate groups, were combined under the name of prokaryotes (or the kingdom of Drobyanka ( lat. Monera )). Then cyanobacteria were considered a group of bacteria, and the other branch of bacteria began to be identified as so-called archaebacteria (now archaea).
However, in addition to the widely recognized Wöse system, alternative systems of higher-level groups still exist.
The two-empire system (a system with two kingdoms) was a system of biological classification of the highest level of general use until the creation of a system with three domains. She classified life by dividing it into Prokaryotes and Eukaryotes. When the three-domain system was introduced, some biologists still preferred the two-empire system, arguing that the three-domain system overestimated the separation between archaea and bacteria. However, given the current state of knowledge and rapid progress in the field of biology, especially due to genetic analysis, this view has practically disappeared.
The Neomura clade consists of two domains : Archaea and Eukaryota [11] . was proposed by the English biologist Thomas Cavalir-Smith , the theory suggests that the group evolved from Bacteria , and one of the most important changes was the replacement of the cell wall peptidoglycan with other glycoproteins , the origin of naddomain from gram - positive bacteria ( Firmicutes and Actinobacteria ) is also confirmed by the results of comparative analysis of protein genes HSP90 family. [12] In May 2015, the results of a study suggesting the isolation of a new type of archaea, Lokiarchaeota, with the alleged genus Lokiarchaeum , were published. It was isolated on the basis of a genome collected by metagenomic analysis of samples obtained near hydrothermal sources in the Atlantic Ocean at a depth of 2.35 km. Phylogenetic analysis showed that Lokiarchaeota and eukaryotes form a monophyletic taxon. The Lokiarchaeota genome contains about 5,400 genes encoding proteins. Among them were found genes close to the genes of eukaryotes. In particular, the genes encoding proteins responsible for changing the shape of the cell membrane, determining the shape of the cell and the dynamic cytoskeleton . The results of this study confirm the so-called dual -domain, or eocyte hypothesis , according to which eukaryotes appeared as a special group inside the archaea, close to Lokiarchaeota and acquired mitochondria as a result of endosymbiosis [13] . Historically, there are five kingdoms of living organisms: animals , plants , fungi , bacteria and viruses . Since 1977, the kingdoms of protists and archaea have been added, since 1998, chromists .
All kingdoms are united into four kingdoms , or domains : bacteria , archaea , eukaryotes, and viruses . The domain of bacteria is the kingdom of bacteria , the domain of archaea is the kingdom of archaea , the domain of viruses is the kingdom of viruses , the domain of eukaryotes is all other kingdoms.
Biota |
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Description
For prokaryotic cells , the absence of a nuclear envelope is characteristic, DNA is packed without the participation of histones . The type of nutrition is osmotic and autotrophic ( photosynthesis and chemosynthesis ).
The only large circular (in some species, linear) double-stranded DNA molecule, which contains the bulk of the genetic material of the cell (the so-called nucleoid ), does not form a complex with the histone proteins (the so-called chromatin ). Bacteria , including cyanobacteria (blue-green algae), and archaea belong to prokaryotes. The descendants of prokaryotic cells are organelles of eukaryotic cells - mitochondria and plastids .
Prokaryotes divide into two taxons with the rank of a domain (kingdom):
- bacteria ( Bacteria )
- Archaea ( Archaea ) [14] .
The study of bacteria led to the discovery of horizontal gene transfer , which was described in Japan in 1959. This process is widespread among prokaryotes, as well as in some eukaryotes.
The discovery of horizontal gene transfer in prokaryotes made it necessary to take a different look at the evolution of life. Previously, evolutionary theory was based on the fact that species cannot exchange genetic information.
Prokaryotes can exchange genes with each other directly ( conjugation , transformation ) and also with the help of viruses - bacteriophages ( transduction ).
Prokaryotes have a prokaryotic cytoskeleton , although more primitive than eukaryotes. In addition to the homologs of actin and tubulin (MreB and FtsZ), the spirally located building block of the flagellum , flagellin is one of the most important cytoskeletal proteins of bacteria, because it provides the structural background of chemotaxis , the main cellular physiological response of bacteria to a chemical irritant. At least some prokaryotes also contain intracellular structures that can be considered primitive organelles. Membrane organelles (or intracellular membranes) are known in some groups of prokaryotes, such as vacuoles or membrane systems, which have particular metabolic properties, such as photosynthesis or chemolithotrophy . In addition, some species also contain micro-compartments enclosed in carbohydrates that perform various physiological functions (for example, carboxysomes or gas vacuoles). Lithotrophs can form symbiotic relationships, in which case they are called “prokaryotic symbionts.” An example of such a relationship is the symbiosis of chemolithotrophic bacteria with giant polychaete worms .
Special Features
Characteristic features of prokaryotes:
- lack of a well-defined kernel;
- the presence of flagella , plasmids and gas vacuoles ;
- the presence of structures in which photosynthesis occurs;
- forms of reproduction: asexual method, there is a pseudo-sexual process (as a result of which there is only an exchange of genetic information, without increasing the number of cells);
- the size of the ribosome is 70S (according to the sedimentation coefficient, there are other types of ribosomes, as well as subparticles and biopolymers that make up the ribosome );
- the DNA molecule is laid in the form of a loop, complexed by some histone proteins, forming a nucleoid . The bulk of DNA (95%) is actively transcribed at any given time [15] .
Classification of organisms by type of metabolism
All living organisms can be divided into eight main groups depending on the used: energy source, carbon source and electron donor (oxidizable substrate) [16] .
- As an energy source, living organisms can use: the energy of light ( photo ) or the energy of chemical bonds ( chemo ). Additionally, the term paratrof is used to describe parasitic organisms using the energy resources of the host cell.
- As an electron donor (reducing agent), living organisms can use: inorganic substances ( litho ) or organic substances ( organ ).
- As a carbon source, living organisms use: carbon dioxide ( auto ) or organic matter ( hetero ). Sometimes the terms auto and heterotroph are used in relation to other elements that are part of biological molecules in reduced form (for example, nitrogen , sulfur ). In this case, “autotrophic for nitrogen” organisms are species that use oxidized inorganic compounds as a nitrogen source (for example, plants; they can carry out the reduction of nitrates ). And “heterotrophic for nitrogen” are organisms incapable of reducing the oxidized forms of nitrogen and using organic compounds as its source (for example, animals for which amino acids are the source of nitrogen).
The name of the type of metabolism is formed by adding the corresponding roots and adding -trof- at the end of the root. The table shows the possible types of metabolism with examples [17] :
A source energy | Electron donor | Carbon source | Type of metabolism | Examples |
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sunlight A photo- | Organic matter -organo- | Organic matter -heterotroph | Photo organo heterotrophs | Purple nonsulfur bacteria , Halobacteria , Some cyanobacteria . |
Carbon dioxide -autotroph | Photo organo autotrophs | A rare type of metabolism associated with the oxidation of non-digestible substances. Characteristic of some purple bacteria . | ||
Inorganic substances -bit- * | Organic matter -heterotroph | Photo litho heterotrophs | Some cyanobacteria , purple and green bacteria , also heliobacteria . | |
Carbon dioxide -autotroph | Photo litho autotrophs | Higher plants , Algae , Cyanobacteria , Purple sulfur bacteria , Green bacteria . | ||
Energy chemical connections Chemo | Organic matter -organo- | Organic matter -heterotroph | Chemo organo heterotrophs | Animals , Fungi , Most decomposers microorganisms . |
Carbon dioxide -autotroph | Hemo organo autotrophs | Oxidation of hard-to-absorb substances, such as optional methylotrophs , which oxidize formic acid. | ||
Inorganic substances -bit- * | Organic matter -heterotroph | Chemo litho heterotrophs | Methane-forming archaea, Hydrogen bacteria . | |
Carbon dioxide -autotroph | Chemo litho autotrophs | Iron bacteria , Hydrogen bacteria , Nitrifying bacteria , Serobacteria . |
- Some authors use -hydro when water acts as an electron donor.
It is evident from the table that the metabolic possibilities of prokaryotes are much more diverse than eukaryotes, which are characterized by photolithoautotrophic and chemoorganoheterotrophic type of metabolism.
It should be noted that some types of microorganisms can, depending on the environmental conditions (lighting, availability of organic substances, etc.) and the physiological state, carry out the metabolism of a different type. This combination of several types of metabolism is described as mixotrophy .
Morphology and size
Prokaryotic cells have various forms; four main forms of bacteria:
- Cocci - Spherical
- Bacilli - rod-shaped
- Spirochete - spiral
- Vibrio - resembles a comma
- Archeon Haloquadratum has flat square cells.
Most prokaryotes range in size from 1 to 10 μm, but their size can vary from 0.2 μm ( Mycoplasma genitalium ) to 750 μm ( Thiomargarita namibiensis ). Prokaryotic cells are usually much smaller than eukaryotic cells. Consequently, prokaryotes have a greater ratio of surface area to volume, which provides them with a higher metabolic rate, a higher growth rate and, as a result, a shorter generation time than eukaryotes. The minimum size of the prokaryotic genome has certain theoretical limitations. In 1996, Arkady Mushegyan and Evgeny Kunin ( National Center for Biotechnology Information , USA ) suggested that the 256 orthologous genes common for the Gram - negative bacterium Haemophilus influenzae and the gram-positive Mycoplasma genitalium are a good approximation to the minimal set of genes of the bacterial cell [18] . In 2004, a group of researchers from the University of Valencia ( Spain ) proposed a set of 206 protein-coding genes obtained by analyzing several bacterial genomes [19] .
Scientists from the Craig Venter group have been creating an organism with a minimal artificially synthesized genome since 1995 [20] . In 1995, they sequenced the genome of the pathogen of the urinary system of the human Mycoplasma genitalium - the smallest among the currently known organisms capable of self-reproduction. This microorganism contains 517 genes, of which 482 encode proteins . The total genome volume is 580 thousand nucleotide pairs. By 1999 , analyzing the arrangement of transposons in the sequenced genomes, it was possible to establish that from 265 to 350 genes and more than 100 genes are of vital importance for an organism [21] . Further studies by 2005 expanded the list of vital genes [22] . A team of scientists systematically deleted genes to find the minimum set of genes necessary for life. Result: 382 genes. This work was also known as the Minimum Genome Project .
Later, prokaryotic genomes of an even smaller size were discovered, but they all belong to obligate symbiotes — organisms that are not capable of autonomous existence.
In 2003, the Nanoarchaeum equitans gene was sequenced with a size of 490,885 pairs [23] . It was also established that the non-sequenced genome of the Buchnera species has a length of about 450 thousand pairs [24] .
The smallest of the bacterial genomes so far decoded is the genome of the intracellular endosymbiont of phylacids of the Carsonella bacterium, consisting of 159,662 nucleotide pairs and containing only 182 genes encoding proteins. This genome was sequenced by Japanese researchers in 2006 [25] . In 2009, an analysis of non- cultured ARMAN cells from a mine biofilm was performed using three-dimensional cryo - electron tomography . It turned out that the size of ARMAN cells corresponds to the lower predicted limit for living cells: their volume is 0.009–0.04 μm ³. It was also found that ARMAN cells have an average of 92 ribosomes per cell, while Escherichia coli contains about 10 thousand ribosomes in the cell of Escherichia coli . Apparently, ARMAN cost a very small number of metabolites per cell, which raises the question of the minimum needs of living cells. A 3D reconstruction of ARMAN cells in natural habitat has shown that some ARMAN cells attach to other archaea from the Thermoplasmatales order . The cells of these archaea penetrate the ARMAN cell wall , reaching the cytoplasm. The nature of this interaction is unclear; perhaps there is some kind of parasitism or symbiosis . It is possible that ARMAN receive from other archaeal those metabolites that they cannot synthesize themselves [26] .
However, some prokaryotes do not rely on their small size and corresponding to such an evolutionary vector to simplify their genotype. For example, the Desulforudis audaxviator bacterium, found in water samples taken at a depth of 2.8 km underground about four micrometers in length, has survived for millions of years on chemical food sources that occur due to the radioactive decomposition of minerals in the surrounding rock. This makes it the only species that is known as one in its ecosystem. The physiology that allows it to live in these extreme conditions is a tribute to its unusually large genome, consisting of 2,157 genes instead of 1,500 in bacteria of this type.
According to published data, the size varies from 0.58 megabase (1 megabase (Mb) - one million base pairs (bp)) in the intracellular pathogen of Mycoplasma genitalium, to more than 10 Mb in several types of cyanobacteria, with the exception of Bacillus megaterium whose genome is 30 MB. The second smallest genome ever published is Buchnera sp. APS , Acyrthosiphon pisum grain aphid endosymbiont, 641 kb in size. Recently, a research group characterized six genomes smaller than even Mycoplasma, the smallest of which is from Buchnera sp. CCE , Cinara cedri aphid endosymbiont, 0.45 MB in size. As a rule, most genomes are smaller than 5 MB. The question arises is there a connection between the size of the genome and the number of genes? The size of the prokaryotic gene is uniform, about 900–1000 bp. Therefore, it is possible to estimate the density of genes in each sequenced genome. Gene density is more or less constant, both in bacteria and in archaea. We can conclude that, at least in prokaryotes, the genomes have more genes and are also more complex than in eukaryotes. That is, the number of genes reflects the lifestyle. Thus, smaller bacteria are specialists, such as obligate parasites and endosymbionts, and larger bacteria are generalists and may even have a certain degree of development, such as sporulation (spore formation process) in Bacillus . [27]
Plasmids (small DNA molecules that are physically separate from the chromosomes and are able to replicate autonomously) are usually found in bacteria, but occasionally are also found in archaea and eukaryotes. Most often, plasmids are double-stranded ring molecules. Despite their ability to reproduce, plasmids, like viruses, are not considered as living organisms. Plasmid sizes range from less than 1 thousand to 400–600 thousand base pairs (pp). Some plasmids are contained in the cell in the amount of one or two copies, others in the amount of several dozen. Plasmids of different classes can coexist in a cell. In nature, plasmids usually contain genes that increase the adaptability of bacteria to the environment (for example, provide resistance to antibiotics). If the smallest plasmids contain less than 2 thousand base pairs, the so-called megaplasmids include hundreds of thousands of base pairs (usually up to 600 thousand). In this case, it is already difficult to draw a clear boundary between the megaplasmid and the . Some types of bacteria can simultaneously contain many different plasmids, so their total genetic material is larger than that of the bacterium itself. For example, the symbiotic soil bacterium contains 3 replicons of 3.65, 1.68, and 1.35 million bp in size. (megabases), respectively, in addition to its own chromosome (6.69 megabases) [28] .
Reproduction
Bacteria multiply in three stages. When a population of bacteria enters a very nutrient medium that provides growth, the cells must first adapt to the new environment. The first stage of development (the phase is called the lag-phase) is characterized by slow growth, when the cells first adapt and prepare for rapid growth. The next step is the logarithmic phase or exponential growth, which means that when the number is measured after an equal interval of time, the bacteria begin to multiply with the same factor or coefficient, which is amplified by the number of intervals. This happens until the nutrients run out.
After this phase, the third phase, which is called the “sleep phase,” occurs where the bacteria do not multiply.
Finally, the final growth phase is the death phase, in which the nutrient supply is exhausted and the bacteria die. Many prokaryotes living in depleted environments survive under conditions similar to permanent hibernation , thereby saving energy and reproduce incredibly slowly once in hundreds or even thousands of years. [29]
Lifespan
Organism | Group | Wednesday | Doubling time, min. |
---|---|---|---|
Escherichia coli | bacteria | glucose , salt | 17 |
Bacillus megaterium | bacteria | sucrose , salt | 25 |
Streptococcus lactis | bacteria | milk | 26 |
Staphylococcus aureus | bacteria | heart broth | 27-30 |
Lactobacillus acidophilus | bacteria | milk | 66-87 |
Myxococcus xanthus | bacteria | salt, yeast extract | 240 |
Rhizobium japonicum | bacteria | mannitol , salts, yeast extract | 344–461 |
Mycobacterium tuberculosis | bacteria | synthetic | 792-932 |
Treponema pallidum | bacteria | rabbit testicles | 1980 |
Life expectancy is not clearly defined for unicellular organisms. There are, however, several terms that can be used in this capacity.
First of all, under favorable conditions, the number of unicellular organisms increases exponentially, and the characteristic of this increase is the doubling time of the number of organisms or the time of one generation.
Another characteristic, similar to life expectancy, are the characteristics of the aging process of organisms [31] . Unicellular organisms have two types of aging - “conditional aging”, or chronological aging in the stationary phase, where it is possible to measure the average or maximum lifespan. However, data for the comparative characteristics of unicellular organisms are not available. Another type of aging is “replicative aging,” or aging of the mother cell during each separation of the daughter cell from it, which is usually measured in the number of divisions. For Saccharomyces cerevisiae, the maximum replicative age is about 25 divisions, and for the Caulobacter crescentis bacterium - about 130. For the remaining organisms, there are no data.
Unicellular organisms have a high level of dependence on environmental conditions. With a decrease in temperature, the doubling time and aging rate decrease for almost all of them. Many single-celled organisms can slow the growth rate hundreds of times, and remain frozen for decades and even longer. The presence of nutrients also affects the rate of growth and aging. In addition, many single-celled organisms, under unfavorable conditions, form spores and other inactive forms capable of existence over the years.
Colonies
Usually, a prokaryotic organism is a single cell. Sometimes the descendants of several branches remain bound in a colony. In the case of actinomycetes and many cyanobacteria, a “colony” is a cell line, between which there is a connection and even a certain distribution of functions. True multicellularity , however, is not found in prokaryotes. One of the most characteristic features of a prokaryotic cell is weak compartmentalization, that is, the absence of a multitude of internal sections that are connected through an elemental membrane system. For most prokaryotes, the cytoplasmic membrane is the only cell membrane system. However, its topology is often complex, as membrane folds penetrate deep into the cytoplasm. Cyanobacteria are the only exception to this rule. In them, the apparatus of photosynthesis is located on rows of hermetic membrane bags or thylakoids , which are similar in structure and function to chloroplast thylakoids. However, in cyanobacteria, thylakoids are included in certain organelles, but lie directly in the cytoplasm.
History of the concept
Moners
Moners - as Haeckel called the simplest single-celled organisms without a nucleus . Since the presence of the nucleus is difficult to state in many cases, initially, while microscopic examination methods were relatively imperfect, many forms of life were considered to be nuclear-free. The question of moners is of some interest in view of the fact that the initial appearance of organisms on Earth probably occurred in the form of bodies that were not yet differentiated into the nucleus and protoplasm [32] .
Currently, the term "moners" does not apply.
Evolution
A widespread current model of the evolution of the first living organisms is that these were some forms of prokaryotes that could evolve from protocells , while eukaryotes developed later in the history of life. Some authors have questioned this conclusion, arguing that the current set of prokaryotic species may have evolved from more complex eukaryotic ancestors in the simplification process.
Others claim that three areas of life emerged simultaneously, from a set of diverse cells that formed a single gene pool . This contradiction was summarized in 2005: [33]
There is no consensus among biologists regarding the position of eukaryotes in the general scheme of cell evolution . Current opinions on the origin and position of eukaryotes cover a wide range, including opinions that eukaryotes originated first in evolution and that prokaryotes originate from them, that eukaryotes arose simultaneously with eubacteria and archaebacteria and, therefore, represent the main line of origin of equal age and rank as prokaryotes, that eukaryotes arose as a result of a symbiotic event entailing the endosymbiotic origin of the nucleus, that eukaryotes originated as a result of a symbiotic event, Healing of the simultaneous endosymbiotic origin of the flagellum and nucleus, in addition to many other models that have been reviewed and summarized elsewhere.
The most ancient of the known fossilized prokaryotes were laid about 3.5 billion years ago, only about 1 billion years after the formation of the earth's crust. Eukaryotes appear only later in the fossil record and can be formed as a result of endosymbiosis of several ancestors of prokaryotes. The oldest known fossil eukaryotes are about 1.7 billion years old. However, some genetic evidence suggests that eukaryotes appeared 3 billion years ago.
While the Earth is the only place in the universe where life is known to exist, some believe that Mars has evidence of fossil or living prokaryotes. However, this possibility remains the subject of considerable debate and skepticism.
See also
- Nitrogen Fixation - The process of reducing the nitrogen molecule and incorporating it into its biomass by prokaryotic microorganisms.
- Comparison of the cell structure of bacteria, plants, animals and fungi
- Eukaryotes
- Systematics of archaea and Systematics of bacteria
- Horizontal gene transfer
Notes
- ↑ Staley JT The Bacterial species dilemma and the genomic-phylogenetic species concept (eng.) // Philos. Trans. R. Soc. Lond., B, Biol. Sci. : journal. - 2006. - Vol. 361 , no. 1475 . - P. 1899-1909 . - DOI : 10.1098 / rstb.2006.1914 . - PMID 17062409 .
- ↑ Zuckerkandl E., Pauling L. Molecules as documents of evolutionary history (Neop.) // J. Theor. Biol .. - 1965. - Vol . 8 , No. 2 . - p . 357-366 . - DOI : 10.1016 / 0022-5193 (65) 90083-4 . - PMID 5876245 .
- Bert Talbert PB, Henikoff S. Histone variants - epitome of the epigenome (English) // Nature Reviews Molecular Cell Biology: journal. - 2010. - Vol. 11 - P. 264-275 . - DOI : 10.1038 / nrm2861 .
- ↑ Sandman K., Reeve JN Archaeal histones fold (Eng.) // Curr. Opin. Microbiol: journal. - 2006. - Vol. 9 - P. 520-525 . - DOI : 10.1016 / j.mib.2006.08.003 .
- ↑ in bacteria, translation begins with formylmethionine
- ↑ 1 2 3 Zillig W. Comparative biochemistry of Archaea and Bacteria (Neopr.) // Curr. Opin. Gen. Dev .. - 1991. - December ( t. 1 , № 4 ). - p . 544-551 . - DOI : 10.1016 / S0959-437X (05) 80206-0 . - PMID 1822288 .
- ↑ Bell SD, Jackson SP Mechanism and regulation of archaea (Eng.) // Curr. Opin. Microbiol. : journal. - 2001. - April ( vol. 4 , no. 2 ). - P. 208-213 . - DOI : 10.1016 / S1369-5274 (00) 00190-9 . - PMID 11282478 .
- ↑ Reeve JN Archaeal chromatin and transcription (Neopr.) // Mol. Microbiol .. - 2003. - May ( vol. 48 , No. 3 ). - p . 587-598 . - PMID 12694606 .
- ↑ Kelman LM, Kelman Z. Archaea: an archetype for replication initiation studies? (English) // Mol. Microbiol. : journal. - 2003. - May ( vol. 48 , no. 3 ). - P. 605-615 . - PMID 12694608 .
- ↑ Phillips G., Chikwana VM, Maxwell A., et al. Discovery and characterization of an amidinotransferase involved in the modification of archaeal tRNA (Eng.) // J. Biol. Chem. : journal. - 2010. - April ( vol. 285 , no. 17 ). - P. 12706-12713 . - DOI : 10.1074 / jbc.M110.102236 . - PMID 20129918 .
- ↑ Cavalier-Smith T. The phagotrophic origin of eukaryotes and phylogenetic classification of Protozoa (Eng.) // Int. J. Syst. Evol. Microbiol. : journal. - 2002. - March ( vol. 52 , no. Pt 2 ). - P. 297-354 . - PMID 11931142 .
- B. Chen B., Zhong D., Monteiro A. Comparative family of genes across all kingdoms of organisms (English) // BMC Genomics: journal. - 2006. - June ( vol. 7 ). - DOI : 10.1186 / 1471-2164-7-156. .
- ↑ Spang A. , Saw JH , Jørgensen SL , Zaremba-Niedzwiedzka K. , Martijn J. , Lind AE , van Eijk R. , Schleper C. , Guy L. , Ettema TJ Complex archaea that bridge the gap between prokaryotes and eukaryotes. (English) // Nature. - 2015. - DOI : 10.1038 / nature14447 . - PMID 25945739 .
- Ese Woese CR, Kandler O., Wheelis ML; Archives , Bacteria, and Eucarya; Proc. Natl. Acad. Sci. USA. - 1990. - T. 87 . - p . 4576-4579 .
- ↑ O.-I. L. Bekish. Medical biology. - Vitebsk: Urajay, 2000.
- ↑ Microbiology: a textbook for students. higher studies. institutions / A. I. Netrusov, I. B. Kotova - Moscow: Akademiya Publishing Center, 2006. - 352 p. ISBN 5-7695-2583-5
- ↑ Microbiology: a textbook for students. biol. specialties of high schools / M.V. Gusev, L.A. Mineev - 4th ed., Sr. - M .: Publishing Center "Academy", 2003. - 464 p. ISBN 5-7695-1403-5
- ↑ Mushegian A., Koonin E. A minimal gene set for cellular life (comparison) complete bacterial genomes (Eng.) // Proceedings of the National Academy of Sciences : journal. - National Academy of Sciences , September 1996. - Vol. 93 . - P. 10268-10273 .
- ↑ Rosario Gil, Francisco J. Silva, Juli Peretó, Andrés Moya. A minimal gene set for a cellular life cycle . // Microbiology and Molecular Biology Reviews : journal. - American Society for Microbiology , September 2004. - Vol. 68 , no. 3 - P. 518-537 . - DOI : 10.1128 / MMBR.68.3.518-537.2004 .
- ↑ Error in footnotes ? : Invalid
<ref>
;Venter-2010
does not have text for footnotes - Ly Clyde A. Hutchison III, Scott N. Peterson, Steven R. Gill, Robin T. Cline, Owen White, Claire M. Fraser, Hamilton O. Smith, J. Craig Venter. Global Transposon Mutagenesis and a Minimal Mycoplasma Genome (Eng.) // Science: journal. - 10 December 1999. - Vol. 286 , no. 5447 . - P. 2165-2169 . - DOI : 10.1126 / science.286.5447.2165 .
- ↑ John I. Glass, Nacyra Assad-Garcia, Nina Alperovich, Shibu Yooseph, Matthew R. Lewis, et al. Essential genes of a minimal bacterium (English) // Proceedings of the National Academy of Sciences . - National Academy of Sciences , January 10, 2006. - Vol. 103 , no. 2 - P. 425-430 . - DOI : 10.1073 / pnas.0510013103 . HTML version . Supporting Information .
- ↑ Waters, E. et al. The genome of Nanoarchaeum equitans: Insights into early parasitism (Eng.) // Proceedings of the National Academy of Sciences : journal. - National Academy of Sciences , 2003. - Vol. 100 - P. 12984-12988 . - DOI : 10.1073 / pnas.1735403100 . Html version .
- ↑ Rosario Gil, Beatriz Sabater-Muñoz, Amparo Latorre, Francisco J. Silva, Andrés Moya. Extreme genome reduction in Buchnera spp.: Toward the minimal genome needed for symbiotic life (Eng.) // Proceedings of the National Academy of Sciences : journal. - National Academy of Sciences , April 2, 2002. - Vol. 99 , no. 7 P. 4454-4458 . - DOI : 10.1073 / pnas.062067299 . Html version .
- ↑ Atsushi Nakabachi, Atsushi Yamashita, Hidehiro Toh, Hajime Ishikawa, Helen E. Dunbar, et al. The 160-Kilobase Genome of the Bacterial Endosymbiont Carsonella (eng.) // Science: journal. - 13 October 2006. - Vol. 314 , no. 5797 . - P. 267 . - DOI : 10.1126 / science.1134196 . Archived December 9, 2008. Review article: Markov A. Read the smallest genome .
- Ird Weird, ultra-small microbes turn up in acid mine drainage Neopr (May 3, 2010).
- ↑ [1]
- Int Shintani M. , Sanchez ZK , Kimbara K. Genomics of microbial plasmids: tax identification. (English) // Frontiers In Microbiology. - 2015. - Vol. 6 - P. 242—242 . - DOI : 10.3389 / fmicb.2015.00242 . - PMID 25873913 .
- ↑ Candidatus Desulforudis audaxviator
- ↑ Growth of bacterial populations . Todar's Online Textbook of Bacteriology .
- ↑ Peter Laun et al. Yeast as a model for chronolohical and reproductive aging - A comparison ( experimental ) // experimental gerontology: journal. - 2006. - Vol. 41 - P. 1208-1212 .
- ↑ Moners // Encyclopedic Dictionary of Brockhaus and Efron : 86 t. (82 t. And 4 additional.). - SPb. , 1890-1907.
- ↑ Martin, William. Woe is the Tree of Life. In Microbial Phylogeny and Evolution: Concepts and Controversies (ed. Jan Sapp). Oxford: Oxford University Press; 2005: 139.
Literature
- Sergeev V.N., Knoll E.X., Zavarzin G.A. The first three billion years of life: from prokaryotes to eukaryotes // Nature. 1996. № 6. S. 54-67.
Links
- Prokaryotes on the site "Veterinary Medicine."