Research – Curious Cat Science and Engineering Blog

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

curiouscat — Sun, 24 Feb 2019 15:24:11 +0000

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.

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.

Widespread Misuse by Those Who Use Antibiotics Infrequently Leads to Resistance

curiouscat — Wed, 19 Dec 2018 14:48:40 +0000

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.

Hope Exists to Reverse Bee Colonies Collapse if We Take Action

curiouscat — Fri, 23 Nov 2018 15:15:38 +0000

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.

Growing Citrus in the Snow

curiouscat — Sun, 27 May 2018 12:43:46 +0000

The system uses the constant ground temperature 2.5 meters (8 feet) below ground to heat a greenhouse. The underground-temperature on his farm is 11 degrees (52 degrees Fahrenheit). Other nearby areas range from 9 to 17 degrees (17 is near a hot spring).

Just circulating air through 64 meters (210 feet) of tubing buried 2.5 meters underground is enough to allow citrus and other plants to thrive. Selling at local farmer’s markets brings in a very high profit for farmers that can grow and sell locally.

Using the power of the sun to grow and the constant ground temperature to keep the air warm enough creates an opportunity to grow all year round. The same principles can be used to cool down indoor temperatures in very hot locations near the equator.

Due to the controlled environment growing organically is easy so that further increases the payoff for this type of farming.

The cost of the system can be as low as $25,000 if you have access to a backhoe to dig the trenches for the air pipes and can do much of the labor yourself. That is the cost of just the heating systems for a conventional greenhouse.

I really like this type of intersection of engineering and business (as well as environment and health benefits – providing healthy local food) that creates value to society by using our knowledge effectively.

Learn more at Citrus in the Snow. The Nebraska farmer (seen in the video) has been growing Citrus in Nebraska this way since 1992.

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

curiouscat — Thu, 24 Aug 2017 14:59:07 +0000

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.

Very Low Frequency Radio Waves Protect Earth

curiouscat — Sat, 05 Aug 2017 13:01:16 +0000

Very Low Frequency (VLF) radio communications signals are transmitted from ground stations at huge powers to communicate with submarines deep in the ocean. While these waves are intended for communications below the surface, they also extend out beyond our atmosphere, shrouding Earth in a VLF bubble. This bubble is even seen by spacecraft high above Earth’s surface, such as NASA’s Van Allen Probes, which study electrons and ions in the near-Earth environment.

The probes have noticed an interesting coincidence – the outward extent of the VLF bubble corresponds almost exactly to the inner edge of the Van Allen radiation belts, a layer of charged particles held in place by Earth’s magnetic fields. Dan Baker, director of the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder, coined this lower limit the “impenetrable barrier” and speculates that if there were no human VLF transmissions, the boundary would likely stretch closer to Earth. Indeed, comparisons of the modern extent of the radiation belts from Van Allen Probe data show the inner boundary to be much farther away than its recorded position in satellite data from the 1960s, when VLF transmissions were more limited.

With further study, VLF transmissions may serve as a way to remove excess radiation from the near-Earth environment. Plans are already underway to test VLF transmissions in the upper atmosphere to see if they could remove excess charged particles — which can appear during periods of intense space weather, such as when the sun erupts with giant clouds of particles and energy.

Dogs and Wolves Share a Sense of Fair Pay

curiouscat — Sat, 01 Jul 2017 15:25:27 +0000

Dogs and wolves share sense of fair play

The scientists tested similarly raised dogs and wolves that lived in packs. Two animals of each species were placed in adjacent cages, equipped with a buzzer apparatus. When the dog or wolf pressed it with their paw, both animals got a reward on some occasions. Other times, the dog or wolf doing the task got nothing while the partner did.

The key finding was that when the partner got a high value treat, the animal doing the task refused to continue with it.

Gray Wolf by Gary Kramer (USFWS), public domain

This is a similar result as that found with Capuchin monkeys that don’t like being paid less than others.

The question of social status or hierarchy also played an important role in the experiments with dogs and wolves of higher rank taking umbrage more quickly.

The human impact on dogs isn’t entirely absent though. Pet dogs are less sensitive to being treated unfairly – probably because of their experience with us!

It is fun to see these results mirror aspects of our psychology. It is fun to see how these experiments test out animal’s responses.

Using Scientific Knowledge to Drive Policies that Create a Better World

curiouscat — Sun, 02 Apr 2017 20:28:47 +0000

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

It is embarrassing that we elect people so ignorant about basic scientific thinking and concepts. We can’t afford that in the world we live in today. There are political differences that should inform debates about what policies we chose to adopt given the science facts we face. But electing people so clueless as we have done is an insult to our species. We should be ashamed of ourselves.

We need to elect leaders like those that took the steps to have the EPA clean up the incredibly polluted USA. We need to elect leaders that put the policies in place to reduce the overfishing in our waters. We need to elect leaders that care about our country and will learn what they need to from those that know the science. That we have a party in the USA that wants to move toward the recent history of Chinese pollution (and the pollution the USA was creating decades ago that lead to the creation of the EPA) is unbelievably sad.

China has learned the cost of such policies and has been taking steps to stop causing such damage to their country. And we elect people that want to go back toward a pro-pollution policy framework. It is crazy that the USA can be so scientifically ignorant that we allow such people to stay in office.

We have to change. We can’t keep putting these people in office and think it is acceptable for us, our children and our grandchildren. We need to expect much more of those we vote for.

The Amazing Reality of Genes and The History of Scientific Inquiry

curiouscat — Sat, 04 Mar 2017 14:43:02 +0000

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.