Life Science – Curious Cat Science and Engineering Blog

Molecular Motor Proteins

curiouscat — Mon, 27 Jan 2020 17:01:52 +0000

Webcast on amazing processes inside cells by Ron Vale.

Molecular motor proteins are fascinating enzymes that power much of the movement performed by living organisms. The webcast provides an overview of the motors that move along cytoskeletal tracks (kinesin and dynein which move along microtubules and myosin which moves along actin). The talk first describes the broad spectrum of biological roles that kinesin, dynein and myosin play in cells. The talk then discusses how these nanoscale proteins convert energy from ATP hydrolysis into unidirectional motion and force production, and compares common principles of kinesin and myosin. The talk concludes by discussing the role of motor proteins in disease and how drugs that modulate motor protein activity can treat human disease.

Ron Vale is a Professor of Cellular and Molecular Pharmacology at the University of California, San Francisco and an Investigator of the Howard Hughes Medical Institute. He is also the founder of the iBiology project.

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.

Animations of Motor Proteins Moving Material Inside Cells

curiouscat — Sat, 23 Dec 2017 16:00:36 +0000

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.

Cats Protect Newborns From Developing Asthma

curiouscat — Sat, 11 Nov 2017 15:30:16 +0000

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.

Mia and her wonderful cat Pippa, the cat alerts Mia’s family if their diabetic daughter is in danger (the cat can sense dangerous blood sugar levels).

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.

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

curiouscat — Sat, 02 Sep 2017 15:40:54 +0000

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.

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.

Insect Architecture

curiouscat — Wed, 26 Apr 2017 19:55:12 +0000

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.