1) Carl Woese and Ralph Wolfe discovered that methanogenic bacteria were not related to other known bacteria based on differences in their 16S ribosomal RNA sequences. This led to the realization that archaea are a distinct third domain of life in addition to bacteria and eukaryotes.
2) 16S rRNA sequences can reveal evolutionary relationships because they contain thousands of "building blocks" that can be aligned and compared between organisms. Archaeal 16S rRNA sequences contained large "gaps" compared to bacterial sequences.
3) The Last Universal Common Ancestor (LUCA) was an early organism from which the domains of archaea and bacteria diverged based on current phylogenetic trees, and it likely lived in an oxygen
This document proposes a hypothesis for the origin of the three cellular domains of life - Archaea, Bacteria, and Eukarya. It suggests that independent transfers of DNA viruses to existing RNA cells gave rise to the three domains. Each transfer stabilized a different version of the proteins involved in translation. The existence of three different founder DNA viruses also explains why each domain has distinct DNA replication machinery. This model aims to address weaknesses in other models and explain why informational proteins differ across domains.
1. The document discusses the six kingdoms of life: Bacteria, Archaebacteria, Protist, Fungi, Plant, and Animal. It describes key characteristics of each kingdom.
2. Five methods for determining evolutionary relationships are discussed: similar structures, breeding behavior, geographic distribution, chromosome comparisons, and biochemistry. Cladistics is the classification system based on evolutionary history/phylogeny.
3. Key terms discussed include: derived trait, fan diagram, heterotroph, autotroph, chemosynthetic, photosynthetic, dichotomous key, and phylogeny. Bacteria are described as unicellular, microscopic organisms without nuclei.
Cell culture refers to growing cells outside of their natural environment in an artificial setting. Some key developments in cell culture include Wilhelm Roux demonstrating maintenance of living cells outside the body in saline buffer in 1885, and Ross Granville Harrison developing the first techniques of cell culture in vitro using frog embryonic tissue in 1907. In the 1920s, composition of salt solutions was formulated for cell cultures. The first cell line, called the "L cell line", was established by Earle in 1948 using cells from mouse tissue. Hayflick and Moorhead defined the finite lifespan of normal human cells in 1961. Cell culture remains an important tool in biomedical research today.
Photosynthetic euglenids originated through a secondary endosymbiosis where a heterotrophic euglenid engulfed a prasinophyte-like green alga and maintained it as a permanent endosymbiont. While the majority live in freshwater, a few species live in marine or brackish habitats. Molecular markers have helped resolve taxonomic confusions and establish phylogenetic relationships among photosynthetic euglenids, though the genus Euglena remains polyphyletic. Fragments of the 18S rDNA gene can be used to identify autotrophic euglenid species with over 90% efficiency.
This document discusses the origin and evolution of viruses and proposes several hypotheses. It suggests that viruses may have played an important role in accelerating evolution by facilitating horizontal gene transfer between species through viral vectors. It also proposes that the ability of genomes to emit DNA/RNA sequences or create new viruses provided an evolutionary advantage as a natural form of biological warfare against predators or competitors. Finally, it cites HIV as an example of a virus that may have evolved from simian viruses as a natural biological weapon that was able to make the jump from non-human primates to humans.
This document summarizes theories on the origin and evolution of viruses. It discusses that viruses likely arose very early in the evolution of life on Earth and may have evolved from primitive RNA replicons. Viruses can emerge through mechanisms like mutation, recombination, and reassortment involving both cellular and viral genetic material. RNA viruses in particular evolve extremely rapidly due to high mutation rates, though some viruses can exhibit periods of evolutionary stasis. Selection plays a key role in driving virus evolution.
Stalking the Fourth Domain in Metagenomic Data: Searching for, Discovering, a...Jonathan Eisen
This document describes research into using metagenomic data to search for novel lineages in the tree of life. The researchers developed methods to search for deeply branching small subunit rRNA genes in Global Ocean Sampling data, but were unable to robustly identify any novel lineages due to difficulties aligning short, distantly related sequences. They had more success identifying novel branches in the RecA and RpoB gene families. Some novel sequences likely come from unknown viruses or ancient paralogs, while others may represent truly novel cellular lineages not previously characterized. Metagenomic analysis offers potential for discovering major undiscovered branches in the tree of life.
This document is Michelle Houle's senior thesis which explores using the Ph.D.-12 peptide phage display library to identify bacteriophage that propagate faster than average. The thesis provides background on bacteriophage and phage display libraries. Houle then serially amplified the Ph.D.-12 library for 3 rounds to enrich for fast propagating phage. 48 phage clones were isolated and sequenced. Two clones were identified as fast propagators based on time course titers and both had mutations near the Shine-Dalgarno region of gene II.
This document proposes a hypothesis for the origin of the three cellular domains of life - Archaea, Bacteria, and Eukarya. It suggests that independent transfers of DNA viruses to existing RNA cells gave rise to the three domains. Each transfer stabilized a different version of the proteins involved in translation. The existence of three different founder DNA viruses also explains why each domain has distinct DNA replication machinery. This model aims to address weaknesses in other models and explain why informational proteins differ across domains.
1. The document discusses the six kingdoms of life: Bacteria, Archaebacteria, Protist, Fungi, Plant, and Animal. It describes key characteristics of each kingdom.
2. Five methods for determining evolutionary relationships are discussed: similar structures, breeding behavior, geographic distribution, chromosome comparisons, and biochemistry. Cladistics is the classification system based on evolutionary history/phylogeny.
3. Key terms discussed include: derived trait, fan diagram, heterotroph, autotroph, chemosynthetic, photosynthetic, dichotomous key, and phylogeny. Bacteria are described as unicellular, microscopic organisms without nuclei.
Cell culture refers to growing cells outside of their natural environment in an artificial setting. Some key developments in cell culture include Wilhelm Roux demonstrating maintenance of living cells outside the body in saline buffer in 1885, and Ross Granville Harrison developing the first techniques of cell culture in vitro using frog embryonic tissue in 1907. In the 1920s, composition of salt solutions was formulated for cell cultures. The first cell line, called the "L cell line", was established by Earle in 1948 using cells from mouse tissue. Hayflick and Moorhead defined the finite lifespan of normal human cells in 1961. Cell culture remains an important tool in biomedical research today.
Photosynthetic euglenids originated through a secondary endosymbiosis where a heterotrophic euglenid engulfed a prasinophyte-like green alga and maintained it as a permanent endosymbiont. While the majority live in freshwater, a few species live in marine or brackish habitats. Molecular markers have helped resolve taxonomic confusions and establish phylogenetic relationships among photosynthetic euglenids, though the genus Euglena remains polyphyletic. Fragments of the 18S rDNA gene can be used to identify autotrophic euglenid species with over 90% efficiency.
This document discusses the origin and evolution of viruses and proposes several hypotheses. It suggests that viruses may have played an important role in accelerating evolution by facilitating horizontal gene transfer between species through viral vectors. It also proposes that the ability of genomes to emit DNA/RNA sequences or create new viruses provided an evolutionary advantage as a natural form of biological warfare against predators or competitors. Finally, it cites HIV as an example of a virus that may have evolved from simian viruses as a natural biological weapon that was able to make the jump from non-human primates to humans.
This document summarizes theories on the origin and evolution of viruses. It discusses that viruses likely arose very early in the evolution of life on Earth and may have evolved from primitive RNA replicons. Viruses can emerge through mechanisms like mutation, recombination, and reassortment involving both cellular and viral genetic material. RNA viruses in particular evolve extremely rapidly due to high mutation rates, though some viruses can exhibit periods of evolutionary stasis. Selection plays a key role in driving virus evolution.
Stalking the Fourth Domain in Metagenomic Data: Searching for, Discovering, a...Jonathan Eisen
This document describes research into using metagenomic data to search for novel lineages in the tree of life. The researchers developed methods to search for deeply branching small subunit rRNA genes in Global Ocean Sampling data, but were unable to robustly identify any novel lineages due to difficulties aligning short, distantly related sequences. They had more success identifying novel branches in the RecA and RpoB gene families. Some novel sequences likely come from unknown viruses or ancient paralogs, while others may represent truly novel cellular lineages not previously characterized. Metagenomic analysis offers potential for discovering major undiscovered branches in the tree of life.
This document is Michelle Houle's senior thesis which explores using the Ph.D.-12 peptide phage display library to identify bacteriophage that propagate faster than average. The thesis provides background on bacteriophage and phage display libraries. Houle then serially amplified the Ph.D.-12 library for 3 rounds to enrich for fast propagating phage. 48 phage clones were isolated and sequenced. Two clones were identified as fast propagators based on time course titers and both had mutations near the Shine-Dalgarno region of gene II.
SARS2 CoVID-19 is so far the latest endemic that has hit the humanity. This presentation is a sincere approach to understand about this class of viruses and the methods that can be used to prevent their further upgradation or genetic modification.
Bacterial virus (Bacteriophage).
Structure of bacteriophage.
Where we can find phage?
Families of bacteriophage.
Life cycle of bacteriophage.
Potential uses of bacteriophage.
Bacteriophage vs. antibiotics.
Factors affecting phage therapy.
1. Bacteriophages are viruses that infect bacteria and were independently discovered in 1915 and 1917. They represent the majority of life forms with an estimated population of 1031.
2. T-phages like T4 and T7 are commonly studied bacteriophages that infect E. coli. They have icosahedral heads and tails used to attach to and inject viral DNA into host cells.
3. The first observations of potential bacteriophages were reported in 1896 but they were more definitively discovered by Frederick Twort in 1915 and Felix d'Herelle in 1917, who coined the term bacteriophage and showed they could be used to treat infections.
Bacteriophages are viruses that infect and replicate inside bacteria. They were first observed in 1917 by Twort and d'Herelle who noticed that bacterial cultures could be dissolved by adding filtrate from sewage. Bacteriophages have complex structures when viewed under electron microscopes and there are over 5000 types classified into 13 families. They carry only the genetic information needed for replication and use the host cell's machinery. Bacteriophages can induce lysogenic conversion by integrating their DNA into the host chromosome, which may enhance the host's virulence by allowing it to produce toxins. They have potential medical applications as alternatives to antibiotics.
Bacteriophages offer an alternative to antibiotics for treating bacterial infections. Bacteriophages are viruses that infect and replicate within bacteria. They have a lytic cycle where they ultimately kill the bacteria or a lysogenic cycle where they integrate into the bacterial genome. Bacteriophages were first discovered in the early 1900s and were used to treat bacterial infections before widespread antibiotic use. They target specific bacteria and can potentially adapt to overcome bacterial resistance. Producing bacteriophages at scale for therapeutic use requires growing bacteria, infecting them with phages, separating and purifying the phages. More research is still needed but bacteriophages show promise as a precision treatment for bacterial infections in the face of growing
The document summarizes research characterizing the toll-interacting protein (TOLLIP) gene in the black abalone (Haliotis cracherodii). The researcher obtained partial TOLLIP sequence information for black abalone and identified other toll-like receptor genes. Quantitative PCR analysis found no significant difference in TOLLIP expression levels between control and bacterium-exposed black abalone digestive gland and gill tissues. Future work will further explore the toll-like receptor pathway and compare laboratory results to field data.
Nothing in Microbiology makes Sense except in the Light of EvolutionMark Pallen
Professor Mark Pallen's Inaugural Lecture at Warwick Medical School, University of Warwick, April 15th 2014.
Storified version of lecture: https://storify.com/mjpallen/palleninaugural
Bacteriophages are viruses that infect bacteria. They were discovered in the early 20th century and come in diverse structural forms. Bacteriophages have a nucleic acid core surrounded by a protein coat. They undergo either a lytic cycle that results in host cell lysis or a lysogenic cycle where the phage DNA integrates into the host chromosome. The lysogenic cycle can confer new properties on the host bacteria through lysogenic conversion. Bacteriophages play important roles in bacterial evolution, epidemiology, and have applications in genetic engineering and controlling bacterial growth.
The document provides a history of molecular biology, describing how it emerged from the union of biochemistry, genetics, microbiology, and virology in the 1930s. It summarizes several major discoveries and events, including identifying DNA as the genetic material in 1944, determining the double helix structure of DNA in 1953, cracking the genetic code in the 1960s, and using new technologies like X-ray crystallography to study macromolecules. The document traces how molecular biology aims to explain life at the molecular level starting from nucleic acids and proteins.
The study of Gregor Mandel put the basis for the advancement in science. Then discovery of nucleic acid allowed researchers to see things in different perspective. Later Kary Mullis provided with the major break through by inventing PCR.
Bacillus subtilis is a ubiquitous, gram-positive bacterium that forms rod-shaped endospores allowing it to survive extreme environmental conditions. It is estimated to produce 60% of commercially available enzymes and is one of the best characterized bacteria, serving as a model organism. B. subtilis has a genome of around 4,100 genes and is widely used in genetic studies and industrial applications due to its ability to secrete proteins and metabolites.
Bacteriophage therapy of infections diseases.Dmitri Popov
This document discusses the use of bacteriophages to treat various bacterial infections caused by E. coli, Salmonella, Shigella, Staphylococcus, and Streptococcus. It provides information on the classification and pathogenic characteristics of these bacteria. Bacteriophages target specific bacteria and can be used as alternatives to antibiotics to treat infections and prevent the spread of disease. The document focuses on using bacteriophages therapeutically and for prophylaxis against various foodborne illnesses and infections.
Bacteriophage, or phages, are viruses that infect bacteria. They have potential medical applications as alternatives to antibiotics. Some companies are studying phages to treat infections caused by bacteria like Staphylococcus aureus and Salmonella. Phages can either undergo a lytic cycle, where they multiply within the host and cause it to lyse, or a lysogenic cycle where they integrate into the host genome and remain dormant. The lysogenic cycle provides a model for how some animal viruses cause transformation of cells.
This document discusses the principles and history of biotechnology. It describes how Herbert Boyer and Stanley Cohen combined DNA splicing with plasmid insertion in bacteria in the 1970s, laying the foundations for the discipline of biotechnology. The document then explains some of the key techniques in biotechnology like genetic engineering, restriction enzymes, cloning vectors, and recombinant DNA technology. It provides examples of how these techniques allow scientists to isolate and introduce desirable genes into organisms.
The document summarizes the key scientific discoveries that established DNA as the genetic material:
1) Experiments in the early 1900s by Morgan, Griffith, and Avery et al. provided early evidence that DNA carries hereditary information and can alter phenotypes.
2) Further experiments in the 1940s-1950s by Chargaff, Hershey and Chase, and Watson and Crick revealed that DNA has a consistent base ratio, is the transforming principle, and forms a double helix structure.
3) The 1958 experiment by Meselson and Stahl, considered "the most beautiful experiment in biology," verified that DNA replication is semi-conservative through labeling DNA with different nitrogen isotopes.
Bacteriophages & Its classification, cycles, therapy, and applicationsZoqiaTariq
These slides are covering multiple aspects of Bacteriophages including History
Classification
Replication
Plaque Assay
Transduction
Phage Therapy and pahge types.
1. Frederick Griffith conducted an experiment in 1928 that showed a "transforming principle" in bacteria, demonstrating that genetic information could be transferred between bacterial strains.
2. He found that mice injected with a mixture of dead, heat-killed bacteria and live bacteria died, and the bacteria in their blood showed a transformation from the normally harmless strain to the deadly strain.
3. This established that some kind of genetic information was being transferred, pioneering the discovery of DNA as the mechanism of inheritance over 30 years later.
Viruses exist in two forms - living and non-living. They can infect virtually any organism and replicate only in certain cell types, known as their host range. Bacteriophages are viruses that infect and parasitize only bacteria. They were discovered in 1915 and 1917 and are referred to as "phages". Phages exist widely in nature and can be isolated from sewage. They have diverse structures and genetics. Phages attack bacteria through either a lytic cycle where they kill the host, or a lysogenic cycle where they integrate into the host genome. During lysogeny, phage genes can be expressed and alter the host cell, sometimes changing it from harmless to pathogenic like certain cholera-causing
El documento presenta los resultados de un laboratorio sobre titulaciones ácido-base. En la primera titulación se midió el pH al agregar volúmenes de 1 ml de HCl 0.1 N a una solución de NaOH 0.1 N, registrando cambios en el pH. Luego, en la segunda titulación se repitió el proceso pero usando KH2PO4 0.1 N y NaOH 0.1 N. Finalmente, los resultados experimentales se compararon con cálculos teóricos.
Este documento resume los conceptos fundamentales de la genética clínica. Explica que la genética clínica estudia y brinda asesoramiento sobre alteraciones genéticas y enfermedades no genéticas del recién nacido. Describe los defectos congénitos, su epidemiología, etiología y formas de diagnóstico. Finalmente, resume diferentes desórdenes y síndromes genéticos como la trisomía 21 y su herencia, así como la herencia multifactorial y el papel de la genética en enfermedades complejas.
SARS2 CoVID-19 is so far the latest endemic that has hit the humanity. This presentation is a sincere approach to understand about this class of viruses and the methods that can be used to prevent their further upgradation or genetic modification.
Bacterial virus (Bacteriophage).
Structure of bacteriophage.
Where we can find phage?
Families of bacteriophage.
Life cycle of bacteriophage.
Potential uses of bacteriophage.
Bacteriophage vs. antibiotics.
Factors affecting phage therapy.
1. Bacteriophages are viruses that infect bacteria and were independently discovered in 1915 and 1917. They represent the majority of life forms with an estimated population of 1031.
2. T-phages like T4 and T7 are commonly studied bacteriophages that infect E. coli. They have icosahedral heads and tails used to attach to and inject viral DNA into host cells.
3. The first observations of potential bacteriophages were reported in 1896 but they were more definitively discovered by Frederick Twort in 1915 and Felix d'Herelle in 1917, who coined the term bacteriophage and showed they could be used to treat infections.
Bacteriophages are viruses that infect and replicate inside bacteria. They were first observed in 1917 by Twort and d'Herelle who noticed that bacterial cultures could be dissolved by adding filtrate from sewage. Bacteriophages have complex structures when viewed under electron microscopes and there are over 5000 types classified into 13 families. They carry only the genetic information needed for replication and use the host cell's machinery. Bacteriophages can induce lysogenic conversion by integrating their DNA into the host chromosome, which may enhance the host's virulence by allowing it to produce toxins. They have potential medical applications as alternatives to antibiotics.
Bacteriophages offer an alternative to antibiotics for treating bacterial infections. Bacteriophages are viruses that infect and replicate within bacteria. They have a lytic cycle where they ultimately kill the bacteria or a lysogenic cycle where they integrate into the bacterial genome. Bacteriophages were first discovered in the early 1900s and were used to treat bacterial infections before widespread antibiotic use. They target specific bacteria and can potentially adapt to overcome bacterial resistance. Producing bacteriophages at scale for therapeutic use requires growing bacteria, infecting them with phages, separating and purifying the phages. More research is still needed but bacteriophages show promise as a precision treatment for bacterial infections in the face of growing
The document summarizes research characterizing the toll-interacting protein (TOLLIP) gene in the black abalone (Haliotis cracherodii). The researcher obtained partial TOLLIP sequence information for black abalone and identified other toll-like receptor genes. Quantitative PCR analysis found no significant difference in TOLLIP expression levels between control and bacterium-exposed black abalone digestive gland and gill tissues. Future work will further explore the toll-like receptor pathway and compare laboratory results to field data.
Nothing in Microbiology makes Sense except in the Light of EvolutionMark Pallen
Professor Mark Pallen's Inaugural Lecture at Warwick Medical School, University of Warwick, April 15th 2014.
Storified version of lecture: https://storify.com/mjpallen/palleninaugural
Bacteriophages are viruses that infect bacteria. They were discovered in the early 20th century and come in diverse structural forms. Bacteriophages have a nucleic acid core surrounded by a protein coat. They undergo either a lytic cycle that results in host cell lysis or a lysogenic cycle where the phage DNA integrates into the host chromosome. The lysogenic cycle can confer new properties on the host bacteria through lysogenic conversion. Bacteriophages play important roles in bacterial evolution, epidemiology, and have applications in genetic engineering and controlling bacterial growth.
The document provides a history of molecular biology, describing how it emerged from the union of biochemistry, genetics, microbiology, and virology in the 1930s. It summarizes several major discoveries and events, including identifying DNA as the genetic material in 1944, determining the double helix structure of DNA in 1953, cracking the genetic code in the 1960s, and using new technologies like X-ray crystallography to study macromolecules. The document traces how molecular biology aims to explain life at the molecular level starting from nucleic acids and proteins.
The study of Gregor Mandel put the basis for the advancement in science. Then discovery of nucleic acid allowed researchers to see things in different perspective. Later Kary Mullis provided with the major break through by inventing PCR.
Bacillus subtilis is a ubiquitous, gram-positive bacterium that forms rod-shaped endospores allowing it to survive extreme environmental conditions. It is estimated to produce 60% of commercially available enzymes and is one of the best characterized bacteria, serving as a model organism. B. subtilis has a genome of around 4,100 genes and is widely used in genetic studies and industrial applications due to its ability to secrete proteins and metabolites.
Bacteriophage therapy of infections diseases.Dmitri Popov
This document discusses the use of bacteriophages to treat various bacterial infections caused by E. coli, Salmonella, Shigella, Staphylococcus, and Streptococcus. It provides information on the classification and pathogenic characteristics of these bacteria. Bacteriophages target specific bacteria and can be used as alternatives to antibiotics to treat infections and prevent the spread of disease. The document focuses on using bacteriophages therapeutically and for prophylaxis against various foodborne illnesses and infections.
Bacteriophage, or phages, are viruses that infect bacteria. They have potential medical applications as alternatives to antibiotics. Some companies are studying phages to treat infections caused by bacteria like Staphylococcus aureus and Salmonella. Phages can either undergo a lytic cycle, where they multiply within the host and cause it to lyse, or a lysogenic cycle where they integrate into the host genome and remain dormant. The lysogenic cycle provides a model for how some animal viruses cause transformation of cells.
This document discusses the principles and history of biotechnology. It describes how Herbert Boyer and Stanley Cohen combined DNA splicing with plasmid insertion in bacteria in the 1970s, laying the foundations for the discipline of biotechnology. The document then explains some of the key techniques in biotechnology like genetic engineering, restriction enzymes, cloning vectors, and recombinant DNA technology. It provides examples of how these techniques allow scientists to isolate and introduce desirable genes into organisms.
The document summarizes the key scientific discoveries that established DNA as the genetic material:
1) Experiments in the early 1900s by Morgan, Griffith, and Avery et al. provided early evidence that DNA carries hereditary information and can alter phenotypes.
2) Further experiments in the 1940s-1950s by Chargaff, Hershey and Chase, and Watson and Crick revealed that DNA has a consistent base ratio, is the transforming principle, and forms a double helix structure.
3) The 1958 experiment by Meselson and Stahl, considered "the most beautiful experiment in biology," verified that DNA replication is semi-conservative through labeling DNA with different nitrogen isotopes.
Bacteriophages & Its classification, cycles, therapy, and applicationsZoqiaTariq
These slides are covering multiple aspects of Bacteriophages including History
Classification
Replication
Plaque Assay
Transduction
Phage Therapy and pahge types.
1. Frederick Griffith conducted an experiment in 1928 that showed a "transforming principle" in bacteria, demonstrating that genetic information could be transferred between bacterial strains.
2. He found that mice injected with a mixture of dead, heat-killed bacteria and live bacteria died, and the bacteria in their blood showed a transformation from the normally harmless strain to the deadly strain.
3. This established that some kind of genetic information was being transferred, pioneering the discovery of DNA as the mechanism of inheritance over 30 years later.
Viruses exist in two forms - living and non-living. They can infect virtually any organism and replicate only in certain cell types, known as their host range. Bacteriophages are viruses that infect and parasitize only bacteria. They were discovered in 1915 and 1917 and are referred to as "phages". Phages exist widely in nature and can be isolated from sewage. They have diverse structures and genetics. Phages attack bacteria through either a lytic cycle where they kill the host, or a lysogenic cycle where they integrate into the host genome. During lysogeny, phage genes can be expressed and alter the host cell, sometimes changing it from harmless to pathogenic like certain cholera-causing
El documento presenta los resultados de un laboratorio sobre titulaciones ácido-base. En la primera titulación se midió el pH al agregar volúmenes de 1 ml de HCl 0.1 N a una solución de NaOH 0.1 N, registrando cambios en el pH. Luego, en la segunda titulación se repitió el proceso pero usando KH2PO4 0.1 N y NaOH 0.1 N. Finalmente, los resultados experimentales se compararon con cálculos teóricos.
Este documento resume los conceptos fundamentales de la genética clínica. Explica que la genética clínica estudia y brinda asesoramiento sobre alteraciones genéticas y enfermedades no genéticas del recién nacido. Describe los defectos congénitos, su epidemiología, etiología y formas de diagnóstico. Finalmente, resume diferentes desórdenes y síndromes genéticos como la trisomía 21 y su herencia, así como la herencia multifactorial y el papel de la genética en enfermedades complejas.
El documento describe una práctica de laboratorio sobre la titulación de ácidos y bases. Los estudiantes registraron los cambios de pH y temperatura al agregar hidróxido de sodio a ácido clorhídrico y fosfato monobásico de potasio. El objetivo era afianzar conocimientos sobre pH, reacciones químicas y soluciones débiles mediante una experiencia comparada con la teoría. El informe presenta resultados en tablas y gráficos junto con un análisis teórico para llegar a conclusiones
Este documento resume varias patologías palpebrales comunes. Describe alteraciones como blefaritis, orzuelo, chalazión, entropión, ectropión y sus causas y síntomas. También cubre tumores benignos como xantelasma y malignos como carcinoma basocelular y escamoso. Explica condiciones como ptosis, lagoftalmía, y alteraciones de la motilidad y posición de los párpados. En resumen, provee una descripción general de las principales enfermedades y anomalías que pueden afectar los pár
Este documento trata sobre varias enfermedades genéticas y congénitas. Describe algunas enfermedades genéticas comunes como el síndrome de Down, la fibrosis quística y la hemofilia. También explica otros trastornos más raros como el síndrome de Angelman, la enfermedad de Tay-Sachs y el síndrome de Patau. Por último, menciona algunas enfermedades congénitas como la escápula elevada, el secuestro broncopulmonar y el síndrome de Ho Kaufman-Mcalister.
This document provides a summary of the history and key discoveries in virology. It discusses how viruses were first observed under electron microscopes in the early 20th century. Many important early discoveries included identifying that viruses caused diseases like polio, smallpox and yellow fever. Major advances included the development of the first vaccines and tissue culture techniques that allowed isolation and study of new viruses. Later work elucidated virus structure and genetics, showing they contain DNA or RNA and can mutate. This established viruses as distinct biological entities and laid the foundation for modern virology.
This document provides an introduction to life science concepts that will be covered in the module. It outlines five key learning objectives, including identifying organisms and conditions that enable their existence, explaining evolution based on evidence, describing classic experiments that model early life conditions, describing unifying themes in life science studies, and showing connections between living things. The document then provides examples of content that will be discussed to meet these objectives, such as a description of the 2009 H1N1 influenza outbreak, the process of genetic reassortment in viruses, definitions of pandemics, and examples of evolution at work.
Evolving Concept of Life Based on Emerging Pieces of Evidence.pptxRoChel18
1) The origin of life on Earth remains one of science's greatest mysteries. Various hypotheses have been proposed but none have been verified.
2) Earth formed around 4.5 billion years ago and may have developed life-supporting conditions by 4.3 billion years ago, although the oldest fossils are only 3.7 billion years old, leaving a gap.
3) Emerging evidence has led scientists to believe that life began through gradual chemical evolution from simple organic molecules to more complex polymers, RNA, and eventually the first prokaryotic cells within the hypothesized conditions of the early Earth.
During the 17th century, important developments in botany included Robert Hooke inventing the microscope in 1665, allowing close examination of plant cells. Anton van Leeuwenhoek later observed live cells under a microscope. Johannes van Helmont conducted experiments on tree water uptake. During the 18th century, Carolus Linnaeus introduced modern taxonomy and plant classification. Gregor Mendel's experiments in the 19th century laid the foundations for genetics. In the 20th century, technology advanced the study of plant structures and genetics at the cellular level, while ecology emerged as a separate discipline. Modern research continues to enhance understanding of plant functions and applications in agriculture.
Evrimin Cokusu( 생명의 기원-한국어) the collapse of evolution- The Orig...babylonboss
This document discusses the theory of evolution and the origin of life. It argues that life is too complex to have originated through natural processes alone and must have had an intelligent creator. It summarizes key points in the development of evolutionary theory from Darwin to modern times, noting that scientists have been unable to explain how the first living cell could have emerged from non-living matter through natural causes. The complex structures of cells and DNA are presented as evidence that life was designed and could not have arisen through random chance alone.
1. The document provides an overview of the history and development of biotechnology from prehistoric times to the present.
2. It discusses early applications of biotechnology in areas like brewing beer and baking bread starting in 6000 BC. Significant advances were made between 1800-1900 with discoveries like pasteurization.
3. The 1900s saw major breakthroughs in understanding genetics including Mendel's laws of heredity and the discovery of DNA's structure. This set the stage for rapid growth of biotechnology research from 1953 onwards with recombinant DNA techniques.
Darwin developed his theory of evolution by natural selection based on observations from his voyage on the HMS Beagle. He saw that different species of finches on the Galapagos Islands had adapted to have beaks suited to the food available on their particular island. This led Darwin to realize that the mechanism of natural selection - where individuals with traits better suited to the environment tend to survive and pass on those traits - over many generations could explain the diversity of life without needing to invoke design. His theory revolutionized scientific thought by providing a naturalistic explanation for both microevolution within species and macroevolution between species over immense periods of time.
This document provides an overview of the history and development of the theory of biological evolution. It describes early religious and philosophical explanations for life's diversity before discussing scientific theories. It outlines disproofs of spontaneous generation and early evolutionary thinkers like Lamarck. It then focuses on Charles Darwin and the key elements of his theory of evolution by natural selection, which he developed based on observations from his voyage on the HMS Beagle. Darwin proposed that life arises through descent with modification from common ancestors, and that natural selection acts on inherited variation between individuals in a population to drive adaptive evolution over many generations.
Thomas Kuhn argued that science proceeds through both normal science and scientific revolutions. Normal science involves incremental progress within an established theoretical framework, while scientific revolutions occur when anomalies arise that cannot be explained by the existing framework. The document discusses how molecular biology arose through a series of scientific revolutions, from Darwin's theory of evolution to the discoveries of DNA's structure and role in heredity. However, recent findings regarding prions may challenge the central paradigm of molecular biology that information flows unidirectionally from genes to proteins.
The document summarizes key concepts in the evolution of life. It discusses early theories of spontaneous generation and the Miller-Urey experiment demonstrating organic molecules can form from inorganic precursors. Modern evolutionary theory developed from Darwin's principles of variation within populations, a struggle for existence, and survival of the fittest. Evidence for evolution includes homologous and vestigial structures, transitional fossils, embryological similarities, and molecular comparisons. Present-day evolution theories have expanded on Darwin's work through ideas like punctuated equilibrium, selfish genes, and the endosymbiotic origin of eukaryotic cells. New species arise through genetic isolation of populations and their gradual differentiation over time. The appearance of human beings is traced from early homin
Forensic entomology "Past, Present and the Future"Nagwa2012
Forensic entomology is the study of insects in legal investigations. It has developed from determining time of death to identifying location and cause of death. Key developments include the use of DNA to identify insect species and detect toxins in insects to determine cause of death. However, more research is still needed to fully understand insect populations and drug effects on growth rates. Future areas of focus include identifying more insect species, studying regional ecosystems, and extracting human DNA from insects to aid identification. Increased popularity of the field is also important to drive further innovation.
This document provides a summary of the history and development of the microscope. It discusses how early Dutch lens makers invented the compound microscope in the 16th century and how Galileo and others later improved its design. It describes how Antony van Leeuwenhoek made additional improvements allowing up to 270x magnification and how he was the first to observe bacteria, blood cells, and other microorganisms. Later scientists like Robert Hooke used microscopes to observe plant and animal cells for the first time.
Evolution Vs Macroevolution Research PaperKatie Parker
The document discusses the theories of evolution and intelligent design as explanations for the origin of life. It provides definitions of key concepts like creation, intelligent design, and natural processes. The document also notes some of the perspectives Christians have regarding the origin of life based on accounts in the Bible, as well as examples evolutionists use regarding traits evolving through natural selection over time.
This document summarizes the contributions of several Spanish scientists:
- Santiago Ramón y Cajal discovered neurons and their connections through contiguity rather than continuity, providing evidence for the Neuron Doctrine. He also discovered axonal growth cones and interstitial cells of Cajal.
- Severo Ochoa helped close the Krebs cycle and discovered the enzyme polynucleotide phosphorylase, which allowed synthesis of RNA in vitro and helped him win the Nobel Prize in Medicine in 1959.
- Joan Oró showed that hydrogen cyanide could produce nitrogenous bases like adenine and amino acids, important in theories of the origin of life on Earth. He also pioneered the theory of
London Great Plague DNA identified for first timeDarren Pauli
Five out of 20 samples from individuals excavated from a mass burial pit from the 1665 Great Plague of London tested positive for Yersinia pestis, confirming plague as the cause of death. Isotopic analysis of the remains provided information on diet and migration, while C14 dating confirmed the mid-17th century timeframe. Archaeological and historical evidence, including accounts of overburdened burial grounds and mass pits, support the pit as a plague burial site. While names of victims could not be identified, one headstone revealed was of plague victim Mary Godfrey. There is no modern risk of plague from the remains.
Kumar bentley: computational embryology_ past, present and futureArchiLab 7
This document summarizes the history of embryology and computational embryology. It discusses key contributions from Aristotle to modern developmental biology. It also describes different types of computational embryogenies, including explicit and implicit embryogenies. The document then presents experiments that evolved predefined shapes using explicit and implicit embryogenies. The results showed that both embryogenies could define morphologies, but the implicit embryogeny did not increase in size as the problem was scaled.
Scientists Through History provides a timeline of famous scientists and their accomplishments, including:
- Aristotle established the foundations of taxonomy and defined nature's scale.
- Leonardo da Vinci studied anatomy extensively and tried to recreate bird flight.
- Antony van Leeuwenhoek invented the simple microscope and was the first to observe bacteria and other microorganisms.
- Robert Hooke coined the term "cell" after observing cork under the microscope and made other advances in physics.
- Charles Darwin developed the theory of evolution by natural selection, providing a mechanism by which species evolved over generations.
This document provides an introduction to microbiology and outlines important historical developments in the field. It discusses key figures like Antony van Leeuwenhoek, who was the first to observe microorganisms using microscopes, and Louis Pasteur, one of the founders of medical microbiology. Some of their major contributions are summarized, such as Leeuwenhoek's discovery of bacteria and Pasteur's disproving of spontaneous generation and development of pasteurization. The document also reviews the work of other scientists who helped establish microbiology as a field of study.
I: Evolution
If I have seen further it is by standing on the shoulders of Giants.
-- Sir Isaac Newton
1
Theories in Science
In the context of scientific inquiry, a theory is:
A conceptual framework supported by a large body of evidence
Broader in scope than a hypothesis. A theory ties information together and leads to specific testable hypotheses
In other words, a theory is a big deal in science, NOT a synonym for guessing
2
2
3
(This used to be a joke, but I’m not laughing anymore.)
3
Historical Overview
What can explain both the unity and diversity of life on Earth?
Organic evolution: genetically based change over time. It acts on individuals in the present, but only manifests in the population over generations.
Natural Selection: mechanism causing the match between organisms and their environment (adaptive evolution = adaptation)
4
4
Traditional views involved unchanging and perfect species inhabiting a young Earth (Old Testament, Linnaeus, etc.)
The emergence of paleontology and geology helped lay the groundwork for Darwin’s contributions
Other areas of research also influenced his thinking, including studies on human population growth
6
6
Fig. 22-2
American Revolution
French Revolution
U.S. Civil War
1900
1850
1800
1750
1795
1809
1798
1830
1831–1836
1837
1859
1837
1844
1858
The Origin of Species is published.
Wallace sends his hypothesis to Darwin.
Darwin begins his notebooks.
Darwin writes essay on descent with modification.
Darwin travels around the world on HMS Beagle.
Malthus publishes “Essay on the Principle of Population.”
Lyell publishes Principles of Geology.
Lamarck publishes his hypothesis of evolution.
Hutton proposes his theory of gradualism.
Linnaeus (classification)
Cuvier (fossils, extinction)
Malthus (population limits)
Lamarck (species can change)
Hutton (gradual geologic change)
Lyell (modern geology)
Darwin (evolution, natural selection)
Wallace (evolution, natural selection)
7
7
Younger stratum
with more recent
fossils
Layers of deposited
sediment
Older stratum
with older fossils
8
8
Several 18th century naturalists (including Erasmus Darwin) suggested life evolves as environments change
Jean-Baptiste Lamarck hypothesized that species evolve through use and disuse of body parts and subsequent inheritance of acquired characteristics
This mechanism is unsupported by evidence (e.g., even if you and your mate lost the same finger, your children would still be born with all ten), but it did refocus subsequent research
Lamarck’s Hypothesis
9
9
10
The miniature phenotype of Bonsai trees is caused by manipulations of a bonsai master, not genetics. Would the next generation still be stunted if we planted their seeds and allowed them to grow naturally?
11
12
After first studying medicine, then theology at Cambridge, Darwin took an unpaid position as naturalist for a 5-year voyage around the world
During his travels on HMS Beagle, he collected thousa ...
Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
In addition to infrastructure and capacity constraints, CAR-Ts face a very different risk-benefit dynamic in autoimmune compared to oncology, highlighting the need for tolerable therapies with low adverse event risk. CAR-NK and Treg-based therapies are also being developed in certain autoimmune disorders and may demonstrate favorable safety profiles. Several novel non-cell therapies such as bispecific antibodies, nanobodies, and RNAi drugs, may also offer future alternative competitive solutions with variable value propositions.
Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Promoting Wellbeing - Applied Social Psychology - Psychology SuperNotesPsychoTech Services
A proprietary approach developed by bringing together the best of learning theories from Psychology, design principles from the world of visualization, and pedagogical methods from over a decade of training experience, that enables you to: Learn better, faster!
8 Surprising Reasons To Meditate 40 Minutes A Day That Can Change Your Life.pptxHolistified Wellness
We’re talking about Vedic Meditation, a form of meditation that has been around for at least 5,000 years. Back then, the people who lived in the Indus Valley, now known as India and Pakistan, practised meditation as a fundamental part of daily life. This knowledge that has given us yoga and Ayurveda, was known as Veda, hence the name Vedic. And though there are some written records, the practice has been passed down verbally from generation to generation.
NVBDCP.pptx Nation vector borne disease control programSapna Thakur
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Local Advanced Lung Cancer: Artificial Intelligence, Synergetics, Complex Sys...Oleg Kshivets
Overall life span (LS) was 1671.7±1721.6 days and cumulative 5YS reached 62.4%, 10 years – 50.4%, 20 years – 44.6%. 94 LCP lived more than 5 years without cancer (LS=2958.6±1723.6 days), 22 – more than 10 years (LS=5571±1841.8 days). 67 LCP died because of LC (LS=471.9±344 days). AT significantly improved 5YS (68% vs. 53.7%) (P=0.028 by log-rank test). Cox modeling displayed that 5YS of LCP significantly depended on: N0-N12, T3-4, blood cell circuit, cell ratio factors (ratio between cancer cells-CC and blood cells subpopulations), LC cell dynamics, recalcification time, heparin tolerance, prothrombin index, protein, AT, procedure type (P=0.000-0.031). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and N0-12 (rank=1), thrombocytes/CC (rank=2), segmented neutrophils/CC (3), eosinophils/CC (4), erythrocytes/CC (5), healthy cells/CC (6), lymphocytes/CC (7), stick neutrophils/CC (8), leucocytes/CC (9), monocytes/CC (10). Correct prediction of 5YS was 100% by neural networks computing (error=0.000; area under ROC curve=1.0).
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2. 16 Chapter 3 My name is LUCA
I have a question regarding Mrs. Hesse. What is agar agar and how did she get the
idea to use it to solidify growth media for bacteria?
Fanny Eilshemius was born in 1850 in Laurel Hill, New Jersey (USA), the daughter
of German immigrants. While traveling through Europe, she met a medical
doctor, Walter Hesse, whom she married. Walter Hesse had a strong interest in
bacteriology. He grew bacteria on gelatin surfaces and was very disappointed that
the gelatin melted so easily. Fanny remembered a recipe she had from Dutch
friends who had lived on the island of Java. They used agar agar, a polymer
extracted from algae to solidify deserts. Agar is ideal because hot solutions contain-
ing 2 percent agar solidify at about 50°C and they only melt again upon boiling.
In addition, most bacteria do not degrade agar, so the introduction of agar pro-
voked a revolution in microbiological laboratories. Bacteria could then conven-
iently be grown on agar surfaces in Petri dishes and the properties of pure cultures,
those containing only one species, could be studied.
What about the breakthrough you mentioned?
In the 1960s a procedure for sequencing DNA fragments was worked out by the
British molecular biologist Frederick Sanger. He developed an elegant method to
shorten DNA fragments base by base and to determine whether the last base in
the fragment is T, C, G, or A (see Chapter 31 for details). This method was so
Figure 4 Colonies of a bacterium on agar
growth medium in a Petri dish. When a
minute amount of cells is streaked out
(starting at 9 o’clock on the dish), cells are so
separated that round colonies can develop
from single cells. Such a cell community then
represents a clone because it originates from
one cell. Depending on its size, a colony may
contain between 50 and 500 million cells.
(Photograph: Anne Kemmling, Goettingen,
Germany.)
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3. Chapter 3 My name is LUCA 17
ingenious that Frederick Sanger was awarded the Nobel Prize (together with
Walter Gilbert and Paul Berg), his second one–see Chapter 28 for the first one.
Progress was enormous, and it is no exaggeration to say that now more than a
billion base sequences are determined every day using this and more advanced
methods. At the University of Illinois in Urbana, the microbiologist Carl Woese
adopted Sanger’s method to learn something about the phylogenetic relationship
of bacterial species. He chose the 16S-rRNA to be sequenced. This RNA is present
in all bacteria because it is essential for the formation of the ribosomal protein
synthesis factories. A milestone in this research was reached in 1977: Carl Woese
and his coworkers published their research paper on the “molecular approach to
prokaryotic systematics.” The relatedness between bacterial species was deter-
mined on the basis of differences in the sequence of 16S-rRNA. At this point, a
sensational experiment appeared on the horizon. Ralph S. Wolfe, another eminent
microbiologist, was working next to the laboratory of Carl R. Woese. He did pio-
neering research on methane-producing microorganisms, especially on the bio-
chemistry of the pathways leading to the production of methane. Of course, Ralph
Wolfe and Carl Woese talked about their work. They decided to collaborate, but
let’s have Ralph Wolfe (Champaign-Urbana, Illinois, USA) tell us about the results
of their experiments:
“Early in his career, Woese had studied the ribosome and was convinced
that this organelle was of very ancient origin, that it had the same function
in all cells, and that variations in the nucleotide sequence in an RNA of the
ribosome could reveal evidence of very ancient events in evolution. He
chose the 16S-rRNA and developed a similarity coefficient that could be
used to compare the relatedness of two different organisms. By 1976 he
had documented the 16S-rRNAs of 60 bacteria.
The research program of Ralph Wolfe concerned the biochemistry of
methane formation by methanogenic bacteria, an area poorly studied
because of the difficulties of cultivating the organisms. Techniques were
developed for culture of cells in a pressurized atmosphere of hydrogen and
carbon dioxide. By 1976 the structure of two unusual coenzymes, coenzyme
M and Factor 420 (a unique deazaflavin), and their enzymology had been
elucidated.
The conjunction occurred with an experiment designed to examine the
16S-rRNA of methanogens. The pressurized atmosphere technique proved
ideal for containing the high level of injected radioactive phosphorus to
label the rRNA of growing cells. The two-dimensional chromatograms of
the labelled 16S-rRNA oligonucleotides from the first experiment were so
different from anything previously seen, that Woese could only conclude
that somehow the wrong RNA had been isolated. The experiment was care-
fully repeated, and this time with the same results: Woese declared, “Wolfe,
these organisms are not bacteria!” “Of course they are, Carl; they look like
bacteria.” “They are not related to anything I’ve seen.” This experiment
marked the birth of the archaea!”
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4. 18 Chapter 3 My name is LUCA
This is an important contemporary testimonial. It led to the conclusion that a third
form of life exists on our planet, the archaea, in addition to the eukaryotes (animals,
plants, fungi) and the bacteria. Ralph Wolfe describes why his colleague Carl
Woese chose 16S-rRNA, then he describes his own research during which the
techniques for growing large amounts of methane-producing microorganisms
were developed. These microorganisms were used for biochemical investigations
that led to the discovery of novel “methano-vitamins” such as coenzyme M or
factor 420.
The studies in Woese’s lab involved growing the methanogenic organisms in
the presence of radioactive phosphate. The 16S-rRNA then contained radioactivity
because of the phosphate bridges present in the molecule. Fragments were iso-
lated, sequenced, and compared with the 16S-rRNAs of E. coli and other organ-
isms. When they compared the sequences obtained, differences were encountered
that could not be explained. Both Carl Woese and Ralph Wolfe were speechless.
The sequences of all the bacterial species studied before were written in essentially
the same language and contained a number of deviations, which gave insight
into the distance between two bacterial species in the phylogenetic tree. But what
the researchers now discovered was that parts of the text were deleted and parts
were written in another language, say in Hebrew. This was something unique,
and this also proved to be the case when the 16S-rRNA of other methanogenic
organisms was sequenced.
Could you please explain a bit more about these differences in the 16S-rRNAs?
Let us imagine a large mosaic, for instance, the triumphal march of Dionysos in
one of the Roman houses in Paphos (Cyprus) discovered in 1962. Like 16S-rRNA,
mosaics also consist of thousands of building blocks. If we change something in
the border surrounding the scene, this will have little effect on the general impres-
sion of the mosaic. It is the same with the sequence of the 16S-rRNA of bacteria.
Trends as well as a few variations in the sequences can be recognized, making it
possible to determine the relatedness of the organisms from which the 16S-rRNAs
were isolated. However, if Dionysos were to be replaced in the mosaic by a mytho-
logical priest, then the number and color of the mosaic tiles would be quite dif-
ferent. It is impossible to derive one figure from the other, so a common ancestor
must be postulated that gave rise to Dionysos, on the one hand, and to the priest,
on the other–an ancestor such as LUCA.
Let’s now look at the sequences of the 16S-rRNAs of Escherichia coli (1542 bases
long) and Bacillus licheniformis (1548 bases) as representatives of the bacteria and
of Methanosarcina mazei (1474 bases), Archaeoglobus fulgidus (1492 bases), and
Methanosphaera stadtmanae (1480 bases), representing the archaea. The alignment
of these sequences results in a beautiful picture (Figure 5), which was done with
the aid of a computer program that searches for maximum correspondence of the
sequences. In order to attain this sequence homology, the computer takes
sequences apart and introduces gaps. Several archaeal “gaps” are apparent, includ-
ing some large ones, but there are also a few bacterial gaps. Identical sequences
c03.indd 18c03.indd 18 9/8/2011 5:46:31 PM9/8/2011 5:46:31 PM
5. Chapter 3 My name is LUCA 19
Figure5Basesequenceofthe16SrRNAsofthreearchaea(Methanosarcina
mazei,Archaeoglobusfulgidus,andMethanosphaerastadtmanae)andtwo
bacteria(EscherichiacoliandBacilluslicheniformis).Thedepictionisbasedona
ClustalW-alignmentunderstandardconditions(W.A.Larkinetal.,Bioinformat-
ics23,2947,2007).VisualizationwasdonewithJaliewusingthestandardcolor
codefornucleotides.(C.Clampetal.,Bioinformatics20,416,2004).Gapswere
insertedintothesequencestoachievemaximalagreement.(Adaptation:Antje
Wollherr,Goettingen,Germany.)
c03.indd 19c03.indd 19 9/8/2011 5:46:31 PM9/8/2011 5:46:31 PM
6. 20 Chapter 3 My name is LUCA
can be seen around 810, 1440, and 1540. Looking at Figure 5 as a whole, the
impression is that the upper three sequences are related as well as the lower two.
These differences made history.
Carl Woese recognized the tremendous importance of his discovery. In the
case of the methanogenic organisms, he had sequenced the 16S-rRNA of an organ-
ism that phylogenetically does not have much in common with the bacteria. This
new domain of organisms was originally called archaebacteria; later the word
“bacteria” was omitted, so now we speak of archaea. The terms methanobacteria
or methane-forming archaebacteria are no longer used; instead, they are called
methanoarchaea.
When these results were published, many microbiologists opposed such views.
But there was also a lot of support, for instance by the German microbiologists
and molecular biologists Otto Kandler, Wolfram Zillig, and Karl Otto Stetter, who
later made important contributions supporting the archaeal concept. In the US,
acceptance was slow but became enthusiastic when major textbooks adopted the
concept of three domains of life.
Now we will jump from the situation in 1977 to the present and look at an actual
phylogenetic tree. It is apparent in Figure 6 that, beginning with LUCA, evolution
proceeded to the domains of Archaea and Eukarya, from which the domain of
Bacteria branched off early in evolution. Not only methane-forming bacteria
belong to the archaea but also the so-called extremophilic microorganisms, which
will be discussed in Chapter 6.
Readers not so familiar with this concept of evolution will find it difficult to
accept the idea that two of the three domains of life on our planet are devoted to
Figure 6 Phylogenetic tree of the three
domains of all living organisms, depicted
clockwise from left to right: Bacteria: Aquifex,
Bacteroides, cyanobacteria, proteobacteria,
Spirochaeta, Bacilli, green filamentous
bacteria. Archaea: Nanoarchaeum equitans
(small dots) attached to Ignicoccus hospitalis,
Thermoproteus, Pyrodictium, Methanococcus,
Methanosarcina, halophilic archaea. Eukarya:
Entamoeba, mucilaginous fungi, humans,
fungi, plants, ciliates, trichomonads,
diplomonads. LUCA (at the bottom) stands
for the Last Universal Common Ancestor.
(Diagram: Anne Kemmling, Goettingen,
Germany.)
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7. Chapter 3 My name is LUCA 21
microorganisms. The third one is reserved for plants, fungi, animals, and us. We
may not forget that bacteria and archaea, on the evolutionary time scale, were by
themselves during most of the biological evolution on Earth. One might even ask
the question why microorganisms allowed the evolution of higher organisms–an
interesting but difficult question. But still, what were the properties of LUCA? It
can be assumed that it was a bacterial- or archaeal-like organism that lived in the
absence of oxygen. LUCA was a fermenting organism or an organism that con-
verted sulfur and molecular hydrogen to hydrogen sulfide. Archaea performing
this kind of fermentation are still present on our planet. How LUCA evolved and
how our current atmosphere developed with oxygen as the indispensable element
will be outlined in the next two chapters.
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