Posts about scientific inquiry

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

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

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

The Challenge of Protecting Us from Evolving Bacterial Threats

I have long been concerned about the practices we continue to use increasing the risks of “superbugs.” I have written about this many times, including: The Overuse of Antibiotics Carries Large Long Term Risks (2005)Are you ready for a world without antibiotics? (2010), Antibiotics Breed Superbugs Faster Than Expected (2010), Entirely New Antibiotic (platensimycin) Developed (2006), Our Poor Antibiotic Practices Have Sped the Evolution of Resistance to Our Last-Resort Antibiotic (2015).

I do also believe the wonderful breakthroughs we make when we invest in science and engineering have made our lives much better and have the potential to continue to do so in many ways, including in dealing with the risks of superbugs. But this is something that requires great effort by many smart people and a great deal of money. It will only happen if we put in the effort.

Winning war against ‘superbugs’

hey won this particular battle, or at least gained some critical intelligence, not by designing a new antibiotic, but by interfering with the metabolism of the bacterial “bugs” — E. coli in this case — and rendering them weaker in the face of existing antibiotics

ROS, or “reactive oxygen species,” include molecules like superoxide and hydrogen peroxide that are natural byproducts of normal metabolic activity. Bacteria usually cope just fine with them, but too many can cause serious damage or even kill the cell. In fact, Collins’ team revealed a few years ago the true antibiotic modus operandi: they kill bacteria in part by ramping up ROS production.

We need to continue to pursue many paths to protecting us from rapidly evolving bacterial risks. Many promising research results will fail to produce usable solutions. We need to try many promising ideas to find useful tools and strategies to protect human health.

How Eratosthenes Estimated the Circumference of the Earth Over 2,000 Years Ago

In this video Carl Sagan explains how Greek astronomer Eratosthenes, in 200 BC, was able to deduce and calculate the earth was a sphere about 40,000 km in circumference.

It is wonderful to see how a bit of thought and curiosity have lead mankind to learn so much.

Related: How do Plants Grow Into the Sunlight?Why is it Colder at Higher Elevations?Great Webcast Explaining the Digestive SystemBiology: How Wounds to Our Skin Heal

Medicinal Plants

Another great webcast from SciShow. In this webcast Hank Green discusses how we have used plants to treat us and improve our health.

In the webcast, Hank also does a good job touching a bit on the scientific inquiry process (which is something I find interesting and I think is very important for people living in society today to understand).

Related: Youyou Tu, The First Chinese Woman to Win a Nobel PrizeRubber TreesPhotosynthesis: Science Explained

Webcasts on the Human Microbiome

The human microbiome is a very interesting aspect of our health and biology.

The 99% figure they quote is mainly silly. It might be technically accurate, but it is much more misleading than accurate (if it is accurate). We have more non-human cells than human but those cells are much smaller and we are overwhelmingly made up of human cells by weight (95+%).

The complexity of healthy bodies is far from understood. It is interesting to watch our understanding of the balancing act going on inside of us. Many foreign “invaders” are critical to our health.

Related: People are Superorganisms With Microbiomes of Thousands of SpeciesPeople Have More Bacterial Cells than Human CellsFighting Superbugs with Superhero BugsWe Have Thousands of Viruses In Us All the Time

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Scientific Inquiry Leads to Using Fluoride for Healthy Teeth

This webcast, from the wonderful SciShow, explores how we discovered fluoride helps prevent tooth decay and how we then used that knowledge and finally discovered why it worked.

I love stories of how we learn for observing what is happening. We don’t always need to innovate by thinking up creative new ideas. If we are observant we can pick up anomalies and then examine the situation to find possible explanations and then experiment to see if those explanations prove true.

When working this way we often are seeing correlation and then trying to figure out which part of the correlation is an actual cause. So in this dental example, a dentist noticed his patients had bad brown stains on their teeth than others populations did.

After investigation the natural fluoridation of the water in Colorado Springs, Colorado, USA seemed like it might be an explanation (though they didn’t understand the chemistry that would cause that result). They also explored the sense that the discolored teeth were resistant to decay.

Even without knowing why it is possible to test if the conditions are the cause. Scientists discovered by reducing the level of fluoridation in the water the ugly brown stains could be eliminated (these stains took a long time to develop and didn’t develop in adults). Eventually scientists ran an experiment in Grand Rapids, Michigan and found fluoridation of the water achieved amazing results for dental health. The practice of fluoridation was then adopted widely and resulted in greatly improved dental health.

In 1901, Frederick McKay, a recent dental school graduate, opened a dental practice in Colorado Springs, Colorado. He was interested in what he saw and sought out other dentists to explore the situation with him but had little success. In 1909, he found some success when renowned dental researcher Dr. G.V. Black collaborate with him.
Dr. H. Trendley Dean, head of the Dental Hygiene Unit at the National Institute of Health built on their work when he began investigating the epidemiology of fluorosis in 1931. It wasn’t until 1945 that the Grand Rapids test started. Science can take a long time to move forward.

Only later did scientists unravel why this worked. The fluoride reacts to create a stronger enamel than if the fluoride is not present. Which results in the enamal being less easily dissolved by bacteria.
Health tip: use a dental stimudent (dental picks) or floss your teeth to maintain healthy gums and prevent tooth decay. It makes a big difference.

Related: Why does orange juice taste so bad after brushing your teeth?Microbiologist Develops Mouthwash That Targets Only Harmful Cavity Causing BacteriaUsing Nanocomposites to Improve Dental Filling PerformanceFinding a Dentist in Chiang Mai, ThailandFalse Teeth For CatsWhy Does Hair Turn Grey as We Age?

Yacouba Sawadogo – The Man Who Stopped the Desert

Quote from the video

Yacouba single-handedly had more impact on the soil conservation in the Sahel than than all the national and international researchers combined.

Dr. Chris Reij, Vrije University of Amsterdam.

As is normally the case making improvements in the real world is challenging and visionaries often face setbacks. Even when they have success that success is threatened by those that want to take the rewards but ignore the lessons. The clip above is a excerpt from the documentary film on his efforts.

Meet Yacouba Sawadogo – The Man Who Stopped the Desert

The simple old farmer’s re-forestation and soil conservation techniques are so effective they’ve helped turn the tide in the fight against the desertification of the harsh lands in northern Burkina Faso.

Over-farming, over-grazing and over population have, over the years, resulted in heavy soil erosion and drying in this landlocked West African nation.

Zai is a very simple and low-cost farming technique. Using a shovel or an axe, small holes are dug into the hard ground and filled with compost. Seeds of trees, millet or sorghum are planted in the compost. The holes catch water during the rainy season, so they are able to retain moisture and nutrients during the dry season.

According to the rules of Zai, Yacouba would prepare the lands in the dry season – exactly the opposite of the local practice. Other farmers and land chiefs laughed at him, but soon realized that he is a genius. In just 20 years, he converted a completely barren area into a thriving 30-acre forest with over 60 species of trees.

Yacouba has chosen not to keep his secrets to himself. Instead, he hosts a workshop at his farm, teaching visitors and bringing people together in a spirit of friendship. “I want the training program to be the starting point for many fruitful exchanges across the region

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