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Scientists Watch Single Cell Organisms Evolve Multicellular Trait in Response to Predation

Posted on February 24, 2019  Comments (2)

The scientists used the ciliate predator Paramecium tetraurelia to select for the de novo evolution of multicellularity in outcrossed populations of C. reinhardtii. They show that multicellular life cycles that evolved were passed on to future generations (the change was heritable). The evolved multicellular life cycles are stable over thousands of asexual generations in the absence of predators. Because C. reinhardtii has no multicellular ancestors, these experiments represent a novel origin of multicellularity.

De novo origins of multicellularity in response to predation

Here we show that de novo origins of simple multicellularity can evolve in response to predation. We subjected outcrossed populations of the unicellular green alga Chlamydomonas reinhardtii to selection by the filter-feeding predator Paramecium tetraurelia. Two of five experimental populations evolved multicellular structures not observed in unselected control populations within ~750 asexual generations.

The control populations remained unicellular. The populations subjected to predation evolved in different ways including one that formed stereotypic eight-celled clusters (Fig. 1A), with an apparent unicellular and tetrad life stage.

electron microscope images of multicellular colonies from evolved populations

Scanning electron micrographs of representative multicellular colonies from evolved populations. (A) Shows an amorphous cluster from population B2. Cell number varies greatly between clusters in this clone and between clones in this population. (B) Shows an eight-celled cluster from population B5. Octads were frequently observed in both populations.

an external membrane is visible around both evolved multicellular colonies, indicating that they formed clonally via repeated cell division within the cluster, rather than via aggregation.

The article also provides details on the scientific inquiry process where theory meets practical realities of observation. I think these ideas are very important and we often gloss over such details. This article was shared as an open access article and is written so that those who are interested in science but are not scientists can understand, which is a valuable. The research was funded by USA National Science Foundation, the John Templeton Foundation, the NASA Astrobiology Institute, a NASA Postdoctoral Program Fellowship and a Packard Foundation Fellowship. And the researchers work at public and private universities. Such research should all be published in an open access manner.

Related: The Amazing Reality of Genes and The History of Scientific Inquiry – Parasite Evolved from Cnidarians (Jellyfish etc.) – Why Don’t All Ant Species Replace Queens in the Colony, Since Some Do – Scientific Inquiry Leads to Using Fluoride for Healthy Teeth – Mechanical Gears Found in Jumping Insects

Virgin Births in the Animal Kingdom

Posted on December 25, 2014  Comments (1)

Spectacular and Real Virgin Births

Scientists are discovering that virgin births occur in many different species; amphibians, reptiles, cartilaginous and bony fish and birds and it happens for reasons we don’t quite understand.

Initially, a virgin birth, also known as parthenogenesis, was thought to be triggered by extreme situations; it was only documented among captive animals, for example, perhaps by the stress, or isolation. A way to continue the bloodline when all other options had gone, when there was no other choice.

Not necessarily. It now appears that some virgin females produce offspring even in the presence of males.

Another interesting area of research for scientists. The value of sex to aid a species’ success is well understood. The value of being able to produce offspring when no males are around seems obvious also. But how this all works is quite interesting and again shows how much we have to learn.

Related: Fungus-gardening Ant Species Has Given Up Sex Completely (2010) – Some Female Sharks Can Reproduce All by Themselves (2007) – Amazon Molly Fish are All Female (2008) – Bdelloid Rotifers Abandoned Sex 100 Million Years Ago (2007)

Epigenetics, Scientific Inquiry and Uncertainty

Posted on September 20, 2014  Comments (1)

Science is full of fascinating ideas. Epigenetics is one area I find particularly interesting. This previous post has a few links to learning more: DNA Passed to Descendants Changed by Your Life.

Angela Saini is one 109 people I follow on Twitter. I don’t see the point in “following” people on Twitter that you have no interest in, I only follow the small number of people that post Tweets I want to read.

In, Epigenetics: genes, environment and the generation game, Angela Saini looks at the confused state of current scientific understand now. It is very difficult to tell if, and if so, to what extent, epigenetic inheritance happens in people.

Professor Azim Surani, a leading developmental biologist and geneticist at the University of Cambridge, adds that while there is good evidence that epigenetic inheritance happens in plants and worms, mammals have very different biology. Surani’s lab carried out thorough studies on how epigenetic information was erased in developing mouse embryos and found that “surprisingly little gets through” the reprogramming process.

Professor Timothy Bestor, a geneticist at Columbia University in New York, is far more damning, claiming that the entire field has been grossly overhyped. “It’s an extremely fashionable topic right now. It’s very easy to get studies on transgenerational epigenetic inheritance published,” he says, adding that all this excitement has lowered critical standards.

Related: Epigenetic Effects on DNA from Living Conditions in Childhood Persist Well Into Middle Age – Medical Study Findings too Often Fail to Provide Us Useful Knowledge – Scientific Inquiry Process Finds That Komodo Dragons Don’t have a Toxic Bite After All

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Explaining the Higgs Boson Particle Again

Posted on March 10, 2014  Comments (0)

comic illustration explaining the Higgs-boson particle

Excerpt from Piled Higher and Deeper by Jorge Cham – go see the entire illustration.

Related: 5% of the Universe is Normal Matter, What About the Other 95%? – At the Heart of All Matter – The god of small things – CERN Pressure Test Failure – Ninja Professors – Friday Fun, CERN Version

DNA Contains Gene Control Instructions

Posted on December 19, 2013  Comments (0)

Scientists discover double meaning in genetic code

Scientists have discovered a second code hiding within DNA. This second code contains information that changes how scientists read the instructions contained in DNA and interpret mutations to make sense of health and disease.
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“For over 40 years we have assumed that DNA changes affecting the genetic code solely impact how proteins are made,” said Stamatoyannopoulos. “Now we know that this basic assumption about reading the human genome missed half of the picture. These new findings highlight that DNA is an incredibly powerful information storage device, which nature has fully exploited in unexpected ways.”

The genetic code uses a 64-letter alphabet called codons. The UW team discovered that some codons, which they called duons, can have two meanings, one related to protein sequence, and one related to gene control. These two meanings seem to have evolved in concert with each other. The gene control instructions appear to help stabilize certain beneficial features of proteins and how they are made.

The discovery of duons has major implications for how scientists and physicians interpret a patient’s genome and will open new doors to the diagnosis and treatment of disease.

“The fact that the genetic code can simultaneously write two kinds of information means that many DNA changes that appear to alter protein sequences may actually cause disease by disrupting gene control programs or even both mechanisms simultaneously,” said Stamatoyannopoulos.

The wonder of DNA continues to amaze.

Related: Epigenetic Effects on DNA from Living Conditions in Childhood Persist Well Into Middle Age – DNA Passed to Descendants Changed by Your Life – DNA based Algorithmic Self-Assembly

Scientific Research Spending Cuts in the USA and Increases Overseas are Tempting Scientists to Leave the USA

Posted on August 29, 2013  Comments (1)

Unlimited Potential, Vanishing Opportunity

Globally, the United States invests more real dollars in research and development than any other country. However, in terms of percentage of gross domestic product, the United States is reducing its investment in scientific research. In fact, of the 10 countries investing the most money in scientific research, the United States is the only country that has reduced its investment in scientific research as a percentage of GDP since 2011.

The study by 16 scientific societies surveyed 3,700 scientists in the USA. As a result of the difficult research funding environment 20% of the scientists are considering going overseas to continue their research careers.

I have written about the likelihood of the USA’s leadership position in science, engineering and technology diminishing. As I stated (see links below), it seemed obvious many other countries were more committed to investing in science now than the USA was (which is different than decades ago when the USA was the country most committed). Various factors would determine how quickly others would shrink the USA’s lead including whether they could setup the infrastructure (scientific, social and economic) and how much damage the anti-science politicians elected in the USA do.

The advantages of being the leader in scientific and engineering research and development are huge and long term. The USA has been coasting on the advantages built up decades ago and the benefits still poor into the USA economy. However, the USA has continued to take economically damaging actions due to the anti-science politics of many who we elect. That is going to be very costly for the USA. The losses will also accelerate sharply when the long term investments others are making bear significant fruit. Once the economic impact is obvious the momentum will continue in that direction for a decade or two even if the USA finally realizes the mistake and learns to appreciate the importance of investing in science.

The good news is that many other countries are making wise investments in science. Humanity will benefit from those investments. The downside of the decisions to cut investments in science (and to actively ignore scientific knowledge) in the USA are largely to move much of the economic gains to other countries, which is regrettable for the future economy of the USA.

Related: Economic Strength Through Technology Leadership – Science, Engineering and the Future of the American Economy – Global Scientific Leadership – Competition to Create Scientific Centers of Excellence – Engineering the Future Economy – Worldwide Science and Engineering Doctoral Degree Data (2005)

People are Superorganisms With Microbiomes of Thousands of Species

Posted on February 25, 2013  Comments (6)

In a recent article in National Geographic Carl Zimmer has again done a good job of explaining the complex interaction between our bodies and the bacteria and microbes that make us sick, and keep us healthy.

The damage done by our indiscriminate use of antibiotics is not just the long term resistance that we create in bacteria (making the future more dangerous for people) that I have written about numerous times but it also endangers the person taking the anti-biotics in the short term. Sometimes the other damage is a tradeoff that should be accepted. But far too often we ignore the damage taking antibiotics too often does.

When You Swallow A Grenade

While antibiotics can discriminate between us and them, however, they can’t discriminate between them and them–between the bacteria that are making us sick and then ones we carry when we’re healthy. When we take a pill of vancomycin, it’s like swallowing a grenade. It may kill our enemy, but it kills a lot of bystanders, too.
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If you think of the human genome as all the genes it takes to run a human body, the 20,000 protein-coding genes found in our own DNA are not enough. We are a superorganism that deploys as many as 20 million genes.
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Before he started taking antibiotics, the scientists identified 41 species in a stool sample. By day 11, they only found 13. Six weeks after the antibiotics, the man was back up to 38 species. But the species he carried six weeks after the antibiotics did not represent that same kind of diversity he had before he took them. A number of major groups of bacteria were still missing.
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They found that children who took antibiotics were at greater risk of developing inflammatory bowel disease later in life. The more antibiotics they took, the greater the risk. Similar studies have found a potential link to asthma as well.

The human body contains trillions of microorganisms — outnumbering human cells by 10 to 1. Because of their small size, however, microorganisms make up only about 1% to 3% of the body’s mass, but play a vital role in human health.

Where doctors had previously isolated only a few hundred bacterial species from the body, Human Microbiome Project (HMP) researchers now calculate that more than 10,000 microbial species occupy the human ecosystem. Moreover, researchers calculate that they have identified between 81% and 99% of all microorganismal genera in healthy adults.

“Humans don’t have all the enzymes we need to digest our own diet,” said Lita Proctor, Ph.D., NHGRI’s HMP program manager. “Microbes in the gut break down many of the proteins, lipids and carbohydrates in our diet into nutrients that we can then absorb. Moreover, the microbes produce beneficial compounds, like vitamins and anti-inflammatories that our genome cannot produce.” Anti-inflammatories are compounds that regulate some of the immune system’s response to disease, such as swelling.

“Enabling disease-specific studies is the whole point of the Human Microbiome Project,” said Barbara Methé, Ph.D., of the J. Craig Venter Institute, Rockville, MD, and lead co-author of the Nature paper on the framework for current and future human microbiome research. “Now that we understand what the normal human microbiome looks like, we should be able to understand how changes in the microbiome are associated with, or even cause, illnesses.”

Read the full NIH press release on the normal bacterial makeup of the body

Related: Tracking the Ecosystem Within Us – What Happens If the Overuse of Antibiotics Leads to Them No Longer Working? – Antibacterial Products May Do More Harm Than Good – Antibiotics Too Often Prescribed for Sinus Woes

Nobel Prize in Physiology or Medicine 2012 for Reprogramming Cells to be Pluripotent

Posted on October 17, 2012  Comments (3)

The Nobel Prize in Physiology or Medicine 2012 was awarded “for the discovery that mature cells can be reprogrammed to become pluripotent.” The prize goes jointly to Sir John B. Gurdon, Gurdon Institute in Cambridge, UK and Shinya Yamanaka, Kyoto University (he is also a senior investigator at the Gladstone Institutes in the USA).

The Nobel Prize recognizes two scientists who discovered that mature, specialised cells can be reprogrammed to become immature cells capable of developing into all tissues of the body. Their findings have revolutionised our understanding of how cells and organisms develop.

John B. Gurdon discovered (in 1962) that the specialisation of cells is reversible. In a classic experiment, he replaced the immature cell nucleus in an egg cell of a frog with the nucleus from a mature intestinal cell. This modified egg cell developed into a normal tadpole. The DNA of the mature cell still had all the information needed to develop all cells in the frog.

Shinya Yamanaka discovered more than 40 years later, in 2006, how intact mature cells in mice could be reprogrammed to become immature stem cells. Surprisingly, by introducing only a few genes, he could reprogram mature cells to become pluripotent stem cells, i.e. immature cells that are able to develop into all types of cells in the body.

These groundbreaking discoveries have completely changed our view of the development and cellular specialisation. We now understand that the mature cell does not have to be confined forever to its specialised state. Textbooks have been rewritten and new research fields have been established. By reprogramming human cells, scientists have created new opportunities to study diseases and develop methods for diagnosis and therapy.

All of us developed from fertilized egg cells. During the first days after conception, the embryo consists of immature cells, each of which is capable of developing into all the cell types that form the adult organism. Such cells are called pluripotent stem cells. With further development of the embryo, these cells give rise to nerve cells, muscle cells, liver cells and all other cell types – each of them specialised to carry out a specific task in the adult body. This journey from immature to specialised cell was previously considered to be unidirectional. It was thought that the cell changes in such a way during maturation that it would no longer be possible for it to return to an immature, pluripotent stage.

Related: 2011 Nobel Prize in Physiology or Medicine – Nobel Prize in Physiology or Medicine 2008 – 2012 Nobel Prize in Chemistry to Robert Lefkowitz and Brian Kobilka

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Should Giant Viruses Be Included on the Tree of Life?

Posted on September 14, 2012  Comments (1)

A new study of giant viruses supports the idea that viruses are ancient living organisms and not inanimate molecular remnants. The study may reshape the universal family tree, adding a fourth major branch to the three that most scientists agree represent the fundamental domains of life. But I am not sure that makes sense. The reason given for viruses not being “life” is that they cannot reproduce themselves – they hijack living cells to reproduce. The research in the past history of viruses as they evolved into current viruses is interesting but I don’t see the reason to classify current viruses as life.

The researchers used a relatively new method to peer into the distant past. Rather than comparing genetic sequences, which are unstable and change rapidly over time, they looked for evidence of past events in the three-dimensional, structural domains of proteins. These structural motifs, called folds, are relatively stable molecular fossils that Рlike the fossils of human or animal bones Рoffer clues to ancient evolutionary events, said University of Illinois crop sciences and Institute for Genomic Biology professor Gustavo Caetano-Anoll̩s, who led the analysis.

“Just like paleontologists, we look at the parts of the system and how they change over time,” Caetano-Anollés said. Some protein folds appear only in one group or in a subset of organisms, he said, while others are common to all organisms studied so far.

“We make a very basic assumption that structures that appear more often and in more groups are the most ancient structures,” he said.

Most efforts to document the relatedness of all living things have left viruses out of the equation, Caetano-Anollés said.

“We’ve always been looking at the Last Universal Common Ancestor by comparing cells,” he said. “We never added viruses. So we put viruses in the mix to see where these viruses came from.”

The researchers conducted a census of all the protein folds occurring in more than 1,000 organisms representing bacteria, viruses, the microbes known as archaea, and all other living things. The researchers included giant viruses because these viruses are large and complex, with genomes that rival Рand in some cases exceed Рthe genetic endowments of the simplest bacteria, Caetano-Anoll̩s said.

Related: Plants, Unikonts, Excavates and SARs – Bacteriophages: The Most Common Life-Like Form on Earth – 8 Percent of the Human Genome is Old Virus Genes – Microbes Retroviruses

Open access paper: Giant Viruses Coexisted With the Cellular Ancestors and Represent a Distinct Supergroup Along With Superkingdoms Archaea, Bacteria and Eukarya

The discovery of giant viruses with genome and physical size comparable to cellular organisms, remnants of protein translation machinery and virus-specific parasites (virophages) have raised intriguing questions about their origin. Evidence advocates for their inclusion into global phylogenomic studies and their consideration as a distinct and ancient form of life.
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Results call for a change in the way viruses are perceived. They likely represent a distinct form of life that either predated or coexisted with the last universal common ancestor (LUCA) and constitute a very crucial part of our planet’s biosphere.

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Quantum Information Theory Postulated As Source of Emergent Theory of Gravity

Posted on August 15, 2011  Comments (0)

I love the advances we have made using our understanding of science and engineering, like the internet, air conditioning and antibiotics. I also love the discussion of research where we really have only educated guesses about what the scientific inquiry process is telling us about the way things are. This research from the University of York is very interesting.

Escaping gravity’s clutches: the black hole breakout

Professor Braunstein says: “Our results didn’t need the details of a black hole’s curved space geometry. That lends support to recent proposals that space, time and even gravity itself may be emergent properties within a deeper theory. Our work subtly changes those proposals, by identifying quantum information theory as the likely candidate for the source of an emergent theory of gravity.”
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Dr Patra adds: “We cannot claim to have proven that escape from a black hole is truly possible, but that is the most straight-forward interpretation of our results. Indeed, our results suggest that quantum information theory will play a key role in a future theory combining quantum mechanics and gravity.”

It is too bad the University of York supports closed science and allows work to be withheld from the public to support outdated publishers business models. Luckily scientists often support open science and publish material openly – I have provided a link for those interested in science instead of the link the University of York gives to a publishers closed system.

Black Hole Evaporation Rates without Spacetime

Verlinde recently suggested that gravity, inertia, and even spacetime may be emergent properties of an underlying thermodynamic theory. This vision was motivated in part by Jacobson’s 1995 surprise result that the Einstein equations of gravity follow from the thermodynamic properties of event horizons. Taking a first tentative step in such a program, we derive the evaporation rate (or radiation spectrum) from black hole event horizons in a spacetime-free manner. Our result relies on a Hilbert space description of black hole evaporation, symmetries therein which follow from the inherent high dimensionality of black holes, global conservation of the no-hair quantities, and the existence of Penrose processes. Our analysis is not wedded to standard general relativity and so should apply to extended gravity theories where we find that the black hole area must be replaced by some other property in any generalized area theorem.

Related: Gravity and the Scientific Method – Gravity May Emerge from Quantum Information – Does Time Exist – Webcast of Astronaut Testing Gravity on the Moon – support open science

New Analysis of Primordial Soup Experiment Half a Century Later

Posted on March 26, 2011  Comments (0)

Open access paper: Primordial synthesis of amines and amino acids in a 1958 Miller H2S-rich spark discharge experiment

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples.

The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment.

The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments.

Related: All present-day Life on Earth Has A Single Ancestor – Life Untouched by the Sun – Amazing Designs of Life – Albert Einstein, Marylin Monroe Hybrid Image