Molecules as documents of evolutionary history

Zuckerkandl, Emile; Pauling, Linus

doi:10.1016/0022-5193(65)90083-4

Cited by 1,108 publications

(531 citation statements)

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“…In contrast to culture methods, which rely on the identification of GI microorganisms by means of a phenotypic characterization, molecular methodologies aim to identify and categorise microorganisms by means of detecting specific molecules inside the cells (e.g., DNA or RNA) (Zuckerkandl and Pauling 1965). The 16S rRNA gene has often been used to identify bacteria because it is universally distributed and appears to have undergone a relatively slow change in base pair composition throughout evolution (Fox et al 1980).…”

Section: Molecular Methodsmentioning

confidence: 99%

Gastrointestinal microorganisms in cats and dogs: a brief review

Garcia-Mazcorro¹,

Minamoto

2013

Arch. med. vet.

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RESUMENEl tracto gastrointestinal (GI) de animales contiene diferentes tipos de microorganismos conocido como la microbiota GI. Por mucho tiempo, la microbiota GI ha generado interés porque los microorganismos GI están involucrados en múltiples procesos fisiológicos en el hospedero, así perpetuando salud o enfermedad. Estudios recientes han demostrado que la microbiota GI de gatos y perros es tan compleja como en humanos y otros animales, revelado con el uso de tecnologías de secuencia modernas y otras técnicas moleculares. La microbiota GI incluye miembros de todos los tres dominios principales de vida (Archaea, Bacterias y Eucariotas), pero las bacterias son el grupo de microorganismos más abundante y metabólicamente activo. El estómago de gatos y perros esta principalmente poblado de Helicobacter spp., el cual en perros puede representar tanto como el 98% de toda la microbiota bacteriana en el estómago. El intestino delgado contiene una microbiota más diversa, conteniendo representantes de al menos cinco diferentes filos bacterianos (principalmente Firmicutes y Bacteroidetes). El intestino grueso contiene el grupo de bacterias más abundante (~10 11 células bacterianas por gramo de contenido intestinal), diverso (al menos diez diferentes filos han sido detectados) y metabólicamente relevante en el tracto GI. La mayoría de las bacterias en el intestino grueso son anaerobios estrictos, los cuales dependen de la fermentación de sustancias no digeridas para subsistir. Aunque estudios recientes han dilucidado las complejidades de la microbiota GI en gatos y perros, más investigación todavía es necesaria para encontrar maneras de manipular exitosamente los microorganismos GI para prevenir y/o tratar enfermedades GI.Palabras clave: gastrointestinal, microbiota, gatos, perros. SUMMARYThe gastrointestinal (GI) tract of animals contains different types of microorganisms known as the GI microbiota. The GI microbiota has long been of interest because of its involvement in multiple physiological processes in the host, influencing health or disease. Recent studies have shown that the GI microbiota of cats and dogs is as complex as the one present in humans and other animals, according to state-of-the-art sequencing technologies and other molecular techniques. The GI microbiota includes members of all three main life domains (Archaea, Bacteria, and Eukaryotes), with bacteria being the most abundant and metabolically active group of microorganisms. The stomach of cats and dogs is mainly inhabited by Helicobacter spp., which in dogs may account for as much as 98% of all gastric bacterial microbiota. The small intestine harbors a more diverse microbiota as it contains representatives from at least five bacterial phyla (mainly Firmicutes and Bacteroidetes). The large intestine harbors the most abundant (~10 11 bacterial cells per gram of intestinal content), diverse (at least 10 bacterial phyla have been identified) and physiologically relevant group of bacteria in the GI tract. Most bacteria in the large intestine are strict an...

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Section: Molecular Methodsmentioning

confidence: 99%

Gastrointestinal microorganisms in cats and dogs: a brief review

Garcia-Mazcorro¹,

Minamoto

2013

Arch. med. vet.

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“…bacteriologists should concentrate instead on the more humble practical task of devising determinative keys to provide the easiest possible identification of species and genera' [5]. This pessimistic situation changed two decades later, thanks to the development of molecular phylogeny, which finds its grounds in the theoretical work of Zuckerkandl and Pauling, who proposed that the sequences of biological macromolecules (proteins and nucleic acids) contained evolutionary information [6]. The first comprehensive molecular phylogenies including macro-and microorganisms were reconstructed by Woese and Fox [7] in the late 1970s.…”

Section: Introductionmentioning

confidence: 99%

Evolution of viruses and cells: do we need a fourth domain of life to explain the origin of eukaryotes?

Moreira¹,

López‐García²

2015

Phil. Trans. R. Soc. B

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The recent discovery of diverse very large viruses, such as the mimivirus, has fostered a profusion of hypotheses positing that these viruses define a new domain of life together with the three cellular ones (Archaea, Bacteria and Eucarya). It has also been speculated that they have played a key role in the origin of eukaryotes as donors of important genes or even as the structures at the origin of the nucleus. Thanks to the increasing availability of genome sequences for these giant viruses, those hypotheses are amenable to testing via comparative genomic and phylogenetic analyses. This task is made very difficult by the high evolutionary rate of viruses, which induces phylogenetic artefacts, such as long branch attraction, when inadequate methods are applied. It can be demonstrated that phylogenetic trees supporting viruses as a fourth domain of life are artefactual. In most cases, the presence of homologues of cellular genes in viruses is best explained by recurrent horizontal gene transfer from cellular hosts to their infecting viruses and not the opposite. Today, there is no solid evidence for the existence of a viral domain of life or for a significant implication of viruses in the origin of the cellular domains.

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“…In their classical review in 1965, Zuckerkandl and Pauling discussed the fundamental properties of biological macromolecules that could potentially form the basis of molecular phylogeny (Zuckerkandl and Pauling 1965). The molecule of choice should be "universal" in physical space and "conserved" in functional and sequence spaces across all living beings, with a sequence "less prone to mutation".…”

Section: Molecular Revolution In Microbial Ecologymentioning

confidence: 99%

“…Comparative analysis of these oligonucleotide catalogues of 16S rRNA molecules further resulted in the first phylogenetic studies of prokaryotes Fox 1977, Fox, Stackebrandt et al 1980), establishing 16S rRNA as the molecule of choice for evolutionary studies. With the realization of the enormous potential in 16S rRNA studies, together with the advent of DNA sequencing methods (Sanger, Nicklen et al 1977, Smith, Sanders et al 1986), much of the focus was on determining their complete nucleotide sequences (Brosius, Palmer et al 1978, Carbon, Ebel et al 1981 because sequences would allow quantitative inferences of phylogenetic relationships (Zuckerkandl andPauling 1965, Fitch andMargoliash 1967). By that time, the principle of using 16S rRNA genes for characterization of microorganisms had gained…”

Section: Molecular Revolution In Microbial Ecologymentioning

confidence: 99%