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

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 InquiryParasite Evolved from Cnidarians (Jellyfish etc.)Why Don’t All Ant Species Replace Queens in the Colony, Since Some DoScientific Inquiry Leads to Using Fluoride for Healthy TeethMechanical Gears Found in Jumping Insects

Widespread Misuse by Those Who Use Antibiotics Infrequently Leads to Resistance

Widespread, occasional use of antibiotics in USA linked with resistance

The increasing prevalence of antibiotic resistance in the U.S. appears more closely linked with their occasional use by many people than by their repeated use among smaller numbers of people, according to a large new study from Harvard T.H. Chan School of Public Health.

The study also found that antibiotic use varies across the nation, and that in areas where particular antibiotics are used more frequently, resistance to those antibiotics is higher.

“We know that efforts to reduce inappropriate use of antibiotics are critical to addressing the problem of antibiotic resistance.

“Our results show that most antibiotic use is occasional—by people taking just one antibiotic course in a year—and that this occasional use is more closely linked with antibiotic resistance than intense, repeated use.”

The problems created by misuse of antibiotics are significant and continuing. The consequences are long term and diffuse. The lack of immediate and damaging impacts makes the continued misuse seem to have little consequence. However, the consequences are dire but not immediate.

In this way it is similar to the problems caused by pumping huge amounts of green house gases into the atmosphere and causing massive climate changes (though delayed by several decades). As a society we really have to get better at changing our behavior when the long term consequences are dire and clear.

It is good to learn from these efforts to understand the most significant aspects of our continued misuse of antibiotics in order to prioritize where we focus our improvement efforts.

Related: What Happens If the Overuse of Antibiotics Leads to Them No Longer Working? (2011)Our Dangerous Antibiotic Practices Carry Great Risks (2012)80% of the Antibiotics in the USA are Used in Agriculture and AquacultureCDC Urges Increased Effort to Reduce Drug-Resistant Infections (2006)Antibiotics Breed Superbugs Faster Than Expected (2010)

Hope Exists to Reverse Bee Colonies Collapse if We Take Action

photo of a bee on a flower

photo by Justin Hunter

The bee colony collapse disorder has been ongoing for more than 10 years and while some scientific understanding has been gained the complexity of the problem continues to stifle progress. The first post I wrote on this blog about colony collapse disorder was published in 2006.

As early as 2007 a virus was found to be one likely factor in bee colony collapse disorder. But progress has been slow especially since likely solutions were fought by those profiting from existing conditions (widespread use of powerful pesticides). In 2012, I wrote another post for this Curious Cat Science blog: Study of the Colony Collapse Disorder Continues as Bee Colonies Continue to Disappear.

Scientist unveils blueprint to save bees

Stefanie Christmann of the International Center for Agricultural Research in Dry Areas will present the results of a new study that shows substantial gains in income and biodiversity from devoting a quarter of cropland to flowering economic crops such as spices, oil seeds, medicinal and forage plants.

The UN conference is already debating new guidelines on pollinators that will recommend reducing and gradually phasing out the use of existing pesticides, but Christmann’s research suggests this can be done without financial pain or a loss of production.

The need for a change is increasingly evident. More than 80% of food crops require pollination but the populations of insects that do most of this work have collapsed. In Germany, this fall is by up to 75% over the past 25 years. Puerto Rico has seen an even sharper decline. Numbers are not available in most countries, but almost all report an alarming decline.

Related: Another Bee Study Finds CCD is Likely Due to Combination of Factors Including Pesticides (2013)The Study of Bee Colony Collapses Continues (2007)Europe Bans Certain Pesticides, USA Just Keeps Looking, Bees Keep Dying (2013)Apple Farmers Use Pigs Instead of Pesticides

Animations of Motor Proteins Moving Material Inside Cells

Very cool. This next video gives a bit more information on how these amazing parts of our cells move material around inside or cells.

This stuff is so interesting. I wish this type of interesting material and informative animations was what my biology education was like in k-12 instead of the boring stuff my classes were instead. I hope students today have better science classes than I did.

It is amazing how such mechanisms evolved to “walk” along transportation microtubules inside our cells.

Related: Molecular Motor Proteins webcast by Ron Vale, Professor of Cellular and Molecular Pharmacology at the University of California, San Francisco (35 minutes)Looking Inside Living CellsScience Explained: Cool Video of ATP Synthase, Which Provides Usable Energy to UsExploring Eukaryotic Cells

Cats Protect Newborns From Developing Asthma

Everyone should appreciate the value of cats (as we do, honoring cats in our blog’s name); yet some people seem oblivious to the greatness of cats. In another demonstration of what we gain by associating with cats, research has shown living with cats as newborns helps protect those with a specific gene variation from developing asthma.

Cats protect newborns against asthma

The results reveal that cats remove the increased risk of developing asthma among children with a particular variation of the gene 17q21, called TT, which has the strongest impact on whether or not a child could develop asthma.

Almost one in three children in the study carried the TT gene variant, regardless of whether or not their mother had asthma.

“it looks like the effect is linked to a particular gene-variant, which goes to show just how complex the development of asthma and allergies are. It’s not only about genes and the environment, but how the two interact, and there’s so much that we still don’t know,”

The research indicates that cats reduce the risk of childhood asthma, pneumonia, and bronchiolitis in genetically susceptible subjects.

And no, dogs do not provide this protection. As with most research the scientists have new paths of inquiry to follow based on these results. Lead author Jakob Stokholm suspects that the reasons cats have this effect but dogs do not, “could be related to the bacteria that cats carry and perhaps fungi or viruses that they bring into the home”. Those questions can be the topic of further research.

Related: Cat Allergy Vaccine Created (2011)Awesome Cat CamThe History of Domestic CatsParasites in the Gut Help Develop a Healthy Immune SystemHypoallergenic Cats (2006)The Amazing Reality of Genes and The History of Scientific Inquiry

Dr. Steve Goodman’s Work as a Field Biologist in Madagascar

Dr. Steve Goodman‘s work is a legendary Field Biologist and spends 9-10 months out of the year conducting research in other countries, with a focus on Madagascar for nearly 30 years. Learn more about the future of Madagascar’s biodiversity and research.

This video is from the great Brain Scoop channel with Emily Graslie; if you are not following that channel I highly recommend doing so for people interested in science.

Related: The Michael Jordan of Field BiologyInsect ArchitectureNew Life Form Found at South African Truck StopNeil Degrasse Tyson: Scientifically Literate See a Different World

Stanford Research Scientists Discover 99% of the Microbes Inside Us are Unknown to Science

Readers of this blog know I am fascinated by the human microbiome. It is amazing how much of our biology is determined by entities within us that are not us (at least not our DNA) (bacteria, viruses etc.). This whole area of study is very new and we have quite a bit to learn. There are scientists across the globe studying this area and learning a great deal.

Stanford study indicates that more than 99% of the microbes inside us are unknown to science

Of all the non-human DNA fragments the team gathered, 99 percent of them failed to match anything in existing genetic databases the researchers examined.

The “vast majority” of it belonged to a phylum called proteobacteria, which includes, among many other species, pathogens such as E. coli and Salmonella. Previously unidentified viruses in the torque teno family, generally not associated with disease but often found in immunocompromised patients, made up the largest group of viruses.

“We’ve doubled the number of known viruses in that family through this work,” Quake said. Perhaps more important, they’ve found an entirely new group of torque teno viruses. Among the known torque teno viruses, one group infects humans and another infects animals, but many of the ones the researchers found didn’t fit in either group. “We’ve now found a whole new class of human-infecting ones that are closer to the animal class than to the previously known human ones, so quite divergent on the evolutionary scale,” he said.

Related: We are Not Us Without The Microbes Within UsWebcasts on the Human MicrobiomePeople are Superorganisms With Microbiomes of Thousands of Species (2013)We Have Thousands of Viruses In Us All the Time (2015)Tracking the Ecosystem Within Us (2007)

Insect Architecture

In this webcast The Brain Scoop takes an interesting look at the homes of eusocial animals and other insects. The video includes many interesting details including that adult weaver ants can’t produce the silk used to weave leaves together so they pick up their larva and use them like a glue stick.

Related: For Many Crops Ants Can Provide Pest Protection Superior or Equal to Chemicals at a Much Lower CostWhy Don’t All Ant Species Replace Queens in the Colony, Since Some DoSymbiotic relationship between ants and bacteriaHuge Termite Mound in Nigeria

We are Not Us Without The Microbes Within Us

I Contain Multitudes is a wonderful book by Ed Young on the microbes within us.

Time and again, bacteria and other microbes have allowed animals to transcend their basic animalness and wheedle their way into ecological nooks and crannies that would be otherwise inaccessible; to settle into lifestyles that would be otherwise intolerable; to eat what they could not otherwise stomach; to succeed against their fundamental nature. And the most extreme examples of this mutual assured success can be found in the deep oceans, where some microbes supplement their hosts to such a degree that the animals can eat the most impoverished diets of all – nothing.

This is another book exploring the wonders of biology and the complexity of the interaction between animals and microbes.

For hundreds of years, doctors have used dioxin to treat people whose hearts are failing. The drug – a modified version of a chemical from foxglove plants – makes the heart beat more strongly, slowly, and regularly. Or, at least, that’s what it usually does. In one patient out of every ten, digoxin doesnt’ work. Its downfall is a gut bacterium called Eggerthella lenta, which converts the drug to an inactive and medically useless form. Only some strains of E. lenta do this.

The complex interactions within us are constantly at work helping us and occasionally causing problems. This obviously creates enormous challenges in health care and research on human health. See related posts: Introduction to Fractional Factorial Designed Experiments, “Grapefruit Juice Bugs” – A New Term for a Surprisingly Common Type of Surprising Bugs and 200,000 People Die Every Year in Europe from Adverse Drug Effects – How Can We Improve?.

Every person aerosolized around 37 million bacteria per hour. This means that our microbiome isn’t confined to our bodies. It perpetually reaches out into our environment.

Avoiding bacteria is not feasible. Our bodies have evolved with this constant interaction with bacteria for millions of years. When we are healthy bacteria have footholds that make it difficult for other bacteria to gain a foothold (as does our immune system fighting off those bacteria it doesn’t recognize or that it recognized as something to fight).

A few pages later he discusses the problem of hospital rooms that were constantly cleaned to kill bacteria and largely sealed to reduce airflow. What happened is those bacteria the sick people had in them were the bacteria that were flourishing (the number of other bacteria to compete for space was small). Opening the windows to welcome the outside air resulted in better results.

Outdoors, the air was full of harmless microbes from plants and soils. Indoors, it contained a disproportionate number of potential pathogens, which are normally rare or absent in the outside world

Human health is a fascinating topic. It is true antibiotics have provided us great tools in the service of human health. But we have resorted to that “hammer” far too often. And the consequences of doing so is not understood. We need those scientists exploring the complex interactions we contain to continue their great work.

Related: People are Superorganisms With Microbiomes of Thousands of Species (2013)Bacteria are Always Living in Our Bodies (2014)Gut Bacteria Explored as Medical Treatment – even for Cancer

Using Scientific Knowledge to Drive Policies that Create a Better World

I have written about the problems of overfishing in the past: Add Over-Fishing to the Huge Government Debt as Examples of How We Are Consuming Beyond Our Means (2012)Fishless Future (2006)North American Fish Threatened (2008)The State of the Oceans is Not Good (2011)European Eels in Crisis After 95% Decline in Last 25 years (2009). This is not a complicated problem. If you just pay attention to the science and make wise decisions with an understanding of systems we can improve the situation.

And the USA has done so. The USA has more work to do, but by taking sensible steps based on an understanding of science we have made significant progress.

How the world can stop overfishing – A case study of U.S. fishery success

By 1996, the US had declared 86 species overfished. Fast forward twenty years, and only 29 species in US waters are classified as overfished. That’s a decrease of 66% from the peak of overfishing in the 1990s.

One year after President Clinton declared the New England ground fishery a federal disaster, congress met in Washington to amend and renew the 20-year-old Fishery Conservation and Management Act. The result was the Magnuson-Stevens Act, a major bipartisan commitment to end overfishing in US waters and promote fish stock recovery.

The goal of the Magnuson-Stevens Act was to create a framework for rebuilding overfished stocks in as short a time as possible. The timeframe for rebuilding a fish stock under the act is typically ten years or less.

To accomplish such a goal, scientists established fishery management plans for each overfished stock and instituted annual catch limits to control overfishing.

By the end of 2015, 89% of fisheries with annual catch limits in place had halted overfishing.

While 64% of the fish stocks managed by the Magnuson-Stevens Act are now rebuilt or recovering, success hasn’t been universal. Certain regional fisheries, such as those in the Gulf of Mexico and New England, have struggled to control overfishing under existing regulations. The act also does a poor job of protecting highly migratory species, such as tuna, swordfish, and sharks, which move freely between different regulatory areas.

We need to build on our successful use of scientific knowledge to make wise decisions and implement wise government policy. Sadly there is an alarming lack of appropriate thinking by many of those we elect to office, in the USA and around the globe. We can’t afford to elect people that don’t have an understanding of how to make wise decisions and how to ensure scientific knowledge forms the basis of policy when it should, such as: overfishing, pollution, global warming, the health care benefits vaccines provide when they are used properly, the dangers of abusing antibiotics, etc..

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The Amazing Reality of Genes and The History of Scientific Inquiry

cover of The Gene

The Gene by Siddhartha Mukherjee is a wonderful book. He does a great job of explaining the history of scientists learning about genes as well as providing understandable explanations for the current scientific understanding of genes and how they impact our lives.

As I have mentioned before, I find biology fascinating even though I found biology classes utterly boring and painful. I wish everyone could learn about biology with the insight people like Siddhartha Mukherjee provide. I realize not everyone is going to find the history and understanding of genes to be fascinating but for those who might this book is a great read. And don’t rule the idea out just because you found biology classes painful.

Life may be chemistry, but it’s a special circumstance of chemistry. Organisms exist not because of reactions that are possible, but because of reactions that are barely possible. Too much reactivity and we would spontaneously combust. Too little, and we would turn cold and die. Proteins enable these barely possible reactions, allowing us to live on the edges of chemical entropy – skating perilously, but never falling in.
– page 134

Whether it is the physics of our solar system or our biology there is a precarious band that allowed beings such as ourselves to evolve.

most genes, as Richard Dawkins describes them, are not “blueprints” but “recipes.” They do not specify parts, but processes; they are formulas, not forms. If you change a blueprint, the final product is change in a perfectly predictable manner: eliminate a widget specified in the plan, and you get a machine with a missing widget. But alteration of a recipe or formula doesn’t not change the product in a predictable manner: if you quadruple the amount of butter in a cake, the eventual effect is more complicated than just a quadruply buttered cake (try it; the whole thing collapses in an oily mess).
– page 454

The is a powerful idea. And when combined with turning genes on and off it is understandable how complex determining genetic impacts on biology and disease are. A few diseases or results (e.g. blue eyes) are nearly as simple as 1 or a few genes being altered in a specific way but most are not nearly so easy. And it isn’t like even that is so easy but with the amazing efforts scientists have made and the advanced tools those scientists created it can now seem simple to identify some such diseases.

The genetic code is universal. A gene from a blue whale can be inserted into a microscopic bacterium and it will be deciphered accurately and with near perfect fidelity. A corollary: there is nothing particularly special about human genes.
– page 480

This is something I have known and understood but it is still amazing. Genes and proteins and how they act to create the incredible diversity of life is something that is awe inspiring.

This book is a wonderful adventure for those interested in life and scientific inquiry.

Related: Epigenetics, Scientific Inquiry and UncertaintyHuman Gene Origins: 37% Bacterial, 35% Animal, 28% EukaryoticUnexpected Risks Found In Editing Genes To Prevent Inherited DisordersEpigenetic Effects on DNA from Living Conditions in Childhood Persist Well Into Middle AgeWhy Don’t All Ant Species Replace Queens in the Colony, Since Some Do

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