Stories tagged Cells

Jul
13
2012

Evolution timeline from 1882: This caricature of Darwin's theory appeared in the 1882 Punch Almanac. The recent evolution timeline created by Kyrk and Sezen is a bit of an improvement.
Evolution timeline from 1882: This caricature of Darwin's theory appeared in the 1882 Punch Almanac. The recent evolution timeline created by Kyrk and Sezen is a bit of an improvement.Courtesy Public domain via Wikipedia
This cool evolution timeline is really fascinating and fun to mess around with. I'm guessing Charles Darwin would agree it's a vast improvement over the one that appeared in Punch Almanac in1882 when he was still alive (see image at right). This new one was created by John Kyrk, a biology-trained artist in San Francisco in collaboration with Dr. Uzay Sezen, a plant biologist from the University of Georgia. The timeline is available in several languages and would be very useful in a classroom setting when studying evolution and paleontology.

The site is interactive and follows the evolution of our universe from the Big Bang to the present. You start it by clicking and sliding the red pyramid on the right. As you scroll across the timeline, various events in the history of the Universe, Solar System and ultimately, the Earth show up on the screen. All along, links also appear that either explain concepts or show examples of them. In the upper left hand corner is a menu linking you to several corollary Flash animations by Kyrk explaining cell biology and how RNA, DNA, cells, water, and other basic elements of life (including viruses) operate. Kyrk thinks animated illustrations are very useful in teaching and remembering ideas and concepts.

All the phases of Earth’s formation and development are covered in the evolution timeline, including the Late Heavy Bombardment, Snowball Earth, Cambrian Explosion, stromatolites, photosynthesis and iron formation. Once life begins to rise up, your computer screen will run amok with Earth’s diverse species populations from the one-celled animals, trilobites and fish to amphibians, reptiles, dinosaurs and mammals – the whole shooting match. All the major extinction events are shown, too.

The site also contains a link to this YouTube video version of someone else working the timeline so you can just sit back and watch how it happens, But I recommend working the interactive page yourself. A lot more happens and is available than the video allows you to see. Note that you’ll need Flash for it to run on your computer.

I wonder how Darwin would have reacted if he were able to see his theory illustrated in this way?

SOURCES
Evolution Timeline

Mar
16
2012

The man behind the video: Drew Berry is a biomedical animator who is responsible for the fascinating scenes in Bjork's music video.
The man behind the video: Drew Berry is a biomedical animator who is responsible for the fascinating scenes in Bjork's music video.Courtesy John D. & Catherine T. MacArther Foundation
In the same vein as this Buzz post, here is another interesting blend of art and science. Bjork teams up with a biomedical animator to create a music video for her song "Hollow."

The animation is a mesmerizing, slightly creepy exercise of scale: it takes you down to the nanoscale, where you watch DNA replicate, then all the way back out to the macroscale, when you zoom out of Bjork's forehead. Interesting, indeed.

Nov
01
2011

Zombies are not real right now because it is impossible. Well, until a scientist screws up. In the movies zombies are people that get infected from a source, it is unlikely that it will happen in our lifetime, but scientifically it will be brains( how ironic ), not bronze that prevails over this threat of zombies. The virus would most likely be like the T virus in Resident Evil, but we probably will never know. What do you think??? I was reading a article from the CDC and they say that it might be possible for a zombie apocalypse to happen! How do you think you would prepare for this??? Well we don't know. We honestly don't. Scientifically we would never truly be ready. And for an Awnser I don't want, "my dad has a gun"!!! Actual science reasons here. Heck, it might be a parasite for all we know, then again, your mom or dad may get it first( that would suck! ), or your sister, or brother. We will never know until we realize that nothing is impossible in science. Scientifically I should say, ELECTRICITY would go down first! Then GAS would eventually run out. Cities would be safe most of the time, because all the people would go out to the country.

Then all the people left would be in shock, and/or, injured and extremely prejudiced, but some will still be sane, like me, I know how to keep alive in a Z.A. but some people would not, but, scientifically someone will be smart and start remaking our civilization, but who knows maybe we will all die? You never know how things will turn out. What are your comments??? I would love to hear them.
EDITED BY LIZA, 11/1/2011: Hey, Buzzketeers! Still need a post-Halloween zombie fix, like ZombieDestroyer here? Head on over to the zombies page. You'll find out about a new zombie-fighting weapon, a real-life zombie-making parasite, and a very long-running thread about whether or not a zombie apocalypse is possible. (And if you feel a need to argue zombie-fighting strategies or likelihood, take it over to that last thread and keep it science-y, y'all!)

Oct
05
2011

You are Cordially Invited

Publication Party, Public Reading, and Book Signing Event

for
FOOL ME TWICE: Fighting the Assault on Science in America
by
SHAWN LAWRENCE OTTO

Introduction by Don Shelby
Emcee Jim Lenfestey

"A gripping analysis of America's anti-science crisis."
Starred Kirkus Review
“In this incredible book, Otto explores the devaluation of science in America.”
Starred Publishers Weekly Review

You know you want to read it. Click here for more info
You know you want to read it. Click here for more infoCourtesy Shawn Lawerence Otto

Tuesday October 18, 2011 at 7PM
Target Performance Hall, Open Book
1011 Washington Avenue South, Minneapolis
(click here for directions and free parking)
This event is free and open to the public

sponsored by
the Loft Literary Center
the Science Museum of Minnesota

no reservation required, but click here to RSVP to help us plan

Beer, wine and light refreshments served
Books for sale at the event
Free book by drawing. To qualify: A) post about the event on Facebook B) tweet at the event with hashtag #FoolMeTwice and mention @ShawnOtto

May
18
2011

R/V Hespérides, docked at Aloha Tower in Honolulu, Hawai`i
R/V Hespérides, docked at Aloha Tower in Honolulu, Hawai`iCourtesy C-MORE
How would you like to be aboard a ship, circumnavigating the globe, collecting samples from the world’s ocean?

That’s exactly what Spanish oceanographers are doing on their Malaspina Expedition aboard the Research Vessel, R/V Hespérides. Scientists and crew left southern Spain in December, reached New Zealand in mid-April, and recently arrived in Hawai`i. The expedition's primary goals are to:

  • build upon the historic 1789-1794 Malaspina expedition to promote interest in marine sciences among the Spanish public, particularly the nation’s youth
  • collect oceanographic and atmospheric data -- chemical, physical and biological – that will help evaluate the impact of global change
  • explore the variety of marine life, including microbes, especially those living in the deep sea
  • CTD: As this oceanographic instrument is lowered over the side of a ship, each gray Niskin “bottle” can be electronically triggered to collect a seawater sample from a different ocean depth.
    CTD: As this oceanographic instrument is lowered over the side of a ship, each gray Niskin “bottle” can be electronically triggered to collect a seawater sample from a different ocean depth.Courtesy C-MORE
    In connection with the latter two goals, the Malaspina scientists met with their colleagues at the Center for Microbial Oceanography: Research and Education (C-MORE). The two groups of scientists are working together. "We can exchange data on the local effects, what's happening around the Hawaiian Islands, and they can tell us what's happening in the middle of the Pacific," said Dr. Dave Karl, University of Hawai`i oceanography professor and Director of C-MORE.

    The Malaspina-C-MORE partnership is the kind of cooperation that can help solve environmental problems which stretch beyond an individual nation’s borders. The R/V Hespérides has now left Honolulu on its way to Panama and Colombia. From there, the scientists expect to complete their ocean sampling through the Atlantic Ocean and return to Spain by July. Buen viaje!

May
02
2011

the ocean's 5 major gyres
the ocean's 5 major gyresCourtesy NOAA
We often talk about the ocean ecosystem. And, indeed, there is really just one, world-wide ocean, since all oceans are connected. An Indian Ocean earthquake sends tsunami waves to distant coasts. Whitecaps look as white anywhere in the world. The ocean swirls in similar patterns.

However, oceanographers do find differences from place to place. For example, let’s take a closer look at the chemistry of two swirls, or gyres as they’re more properly called. Scientists have found a micro difference between the North Atlantic Gyre and the North Pacific Gyre. The Atlantic generally has really low levels of phosphorus, measurably lower than the North Pacific Gyre.

the element phosphorus among its neighbors in the Periodic Table of the Elements
the element phosphorus among its neighbors in the Periodic Table of the ElementsCourtesy modified from Wikipedia
Phosphorus is a very important element in living things. For example, it’s a necessary ingredient in ATP (adenosine tri-phosphate), the energy molecule used by all forms of life. Phosphorus is picked up from seawater by bacteria. All other marine life depends upon these bacteria, either directly or indirectly, for P. Therefore, if you’re bacteria living in the impoverished North Atlantic Gyre, you’d better be really good at getting phosphorus.

And they are!

Oceanographers at the Center for Microbial Oceanography: Research and Education (C-MORE) at the University of Hawai`i have made an important discovery. C-MORE scientists Sallie Chisholm, based at the Massachusetts Institute of Technology and her former graduate student Maureen Coleman, now a scientist at the California Institute of Technology, have been studying two species of oceanic bacteria. Prochlorococcus is an autotrophic bacterium that photosynthesizes its own food; Pelagibacter, is a heterotrophic bacterium that consumes food molecules made by others.

Pacific HOT and Atlantic BATS Stations: Microbial samples were collected at each location.
Pacific HOT and Atlantic BATS Stations: Microbial samples were collected at each location.Courtesy C-MORE
Drs. Chisholm and Coleman took samples of these two kinds of bacteria from both the Atlantic and Pacific Ocean. The Atlantic samples were collected by the Bermuda Atlantic Time-Series (BATS) program. The Pacific samples were collected in the North Pacific Gyre (about 90 miles north of Honolulu) by the Hawai`i Ocean Time-Series (HOT) program. The scientists discovered surprising differences in the genetic code of the bacteria between the two locations:

  • First of all, the Atlantic populations of both bacterial species have more phosphorus-related genes compared to their Pacific cousins. (Picture Atlantic microbes in Superman outfits with a big "P" on their chests!)
  • Secondly, in the Atlantic, Prochlorococcus has different kinds of P-related genes compared to Pelagibacter. Perhaps this means the two microbial species have evolved over time to use different phosphorus sources, to avoid competing with one another for this limited resource.

Drs. Chisholm and Coleman have discovered important micro differences between bacteria of the same species in two oceanic gyres. Now we can better understand how these microbes are working to recycle an important nutrient beneath the whitecaps.

Reference: October 11, 2010 issue of the Proceedings of the National Academy of Sciences

Apr
13
2011

Earth, our place in space
Earth, our place in spaceCourtesy NASA
Life scientists study…well, life. They want to know everything about living things on planet Earth. One of the first things biologists want to know is who’s here. What kinds of plants and animals live in a forest? --or in a field? –or in the ocean?

If you’re an oceanographer who studies marine mammals, perhaps you’d go to sea on a ship with a good pair of binoculars and hunt for whales. As you focused your binoculars you’d be able to see different kinds of whale species. As you looked closer, for example at Humpback Whales, you'd see that each individual whale has a different black-white pattern on its tail. You might even take a biopsy, a small sample of whale flesh, and do a more detailed study of genetic differences among individual Humpbacks.

But what if you’re a microbial oceanographer? You sure can't use binocs to hunt for microbes! How can you study individual differences among tiny creatures that are only one-one-hundredth the width of a human hair? How do you hunt and capture single-celled bacteria, like Prochlorococcus, the most common bacterial species in the world’s ocean?

Invent something!

laser-based micro-fluidic system
laser-based micro-fluidic systemCourtesy C-MORE
Young scientists, Sebastien Rodrigue and Rex Malmstrom, at the Center for Microbial Oceanography: Research and Education (C-MORE) were doing research in Dr. Sallie Chisholm’s C-MORE lab at the Massachusetts Institute of Technology when they adapted a “laser-based micro-fluidic system” used commonly by medical researchers, for the study of marine bacteria. With this method they could put each individual tiny Prochlorococcus cell into its own little pool of seawater.

And then the excitement began.

Prochlorococcus
ProchlorococcusCourtesy Dr. Anne Thompson, MIT
Even in scanning microscope photographs, each Prochlorococcus looks like just another teeny, tiny balloon; we can't see any individual differences. However, Sebastien and Rex used fast and inexpensive genetic methods and discovered an extraordinary variety of individual differences among Prochlorococcus. Of course the variety among these microbes doesn't have to do with tail patterns, like whales. Prochlorococcus vary in their method of getting nutrients, like iron, out of seawater.

So what? Why do we care?

We care A LOT because microbes like Prochlorococcus are operating at the nitty gritty level of cycling not only iron, but also other elements in the ocean. Like carbon. That's right, as in carbon dioxide accumulating in our atmosphere -- and ocean -- causing climate change and associated problems. The more we understand about individual differences among oceanic microbes, the more we'll understand how they influence and respond to changes in Earth's climate.

Mar
10
2011

It seems that there has been a bit of a kerfuffle about this paper in the Journal of CosmoCyanobacteria: Could cells like these have been found in space rocks?
Cyanobacteria: Could cells like these have been found in space rocks?Courtesy Microbial Diversity, Rolf Schauder and David Graham, © 1997
logy, an online-only publication apparently known for publishing controversial points of view endorsing, among other things, the hypothesis that life began outside of the Earth. The paper in question, by NASA researcher Richard Hoover, discusses structures found in three meteorites that visually and chemically resemble bacteria. If these meteorites really contain bacteria whose origins are extraterrestrial (rather than plain old Earth bacteria that contaminated the meteorite samples), it's clear that Hoover has made the kind of discovery that will represent a revolution in scientific thinking.

But that's an awfully big "if". Critics suggest that contamination is vastly more likely (see a nice collection of comments here), and generally criticize the research, the publication, and various other facets of this story.

This whole affair can be read a number of ways: as an illustration of the rule of thumb that "extraordinary claims require extraordinary evidence"; as an example of the politics that sometimes surround scientific research and publication; or even as evidence that people have a way of seeing what they want to see given ambiguous evidence.

But despite all the criticism, I confess that anything suggesting the possibility of extraterrestrial life sets my little heart a-flutterin'. Very few ideas have the same power to catch the imagination as that of alien life: that something so impossible might actually be possible, that science fiction might have some truth, that our understanding of the universe might still be completely and profoundly overturned by something so simple as a few cells inside a space rock. Remember when NASA teased this story about a revolution in astrobiological thinking? I was on pins and needles for days, hoping that they were going to announce definitive evidence of alien life. And, admit it, when you saw this story's headline you were secretly hoping for the same thing...

Mar
07
2011

You probably know that plants "inhale" carbon dioxide and "exhale" oxygen, but did you know that plants also release water into the air when they exhale? This process is called transpiration, and it plays an important part in our planet's water cycle. I mean, just think of all the billions of plants out there, all of them transpiring 24/7--that really adds up.

Unfortunately, increasing carbon dioxide in the atmosphere has yet another impact on our ecosystems--it reduces transpiration. You see, plants have these tiny pores on the undersides of their leaves called stomata. The stomata open and close depending on the amount of carbon dioxide available in the air and how much they need of it.

It's kind of like your eye's iris--your eye needs an ideal amount of light to see, so when it's bright outside, the iris closes in. This shrinks the pupil so that it only takes in a small amount of light. In lower light, the iris opens, making the pupil larger so that it takes in more light. Like your iris, the stomata open and close to let in the right amount of carbon dioxide.

Stomata: These stomata are from an Arabidopsis plant. The top one is open, and the lower one is closed.
Stomata: These stomata are from an Arabidopsis plant. The top one is open, and the lower one is closed.Courtesy KuriPop

Unfortunately, a recent study showed that with carbon dioxide concentrations increasing quickly, plant stomata are closed longer than they were 150 years ago. There are also simply fewer stomata in leaves. While this controls the amount of carbon dioxide they're absorbing, it has the added outcome of limiting the amount of water released into the air from plants. Over time, this could add up to some significant change--but it's a little early to tell for sure what the impacts will be.

It's kind of amazing to see how changes in carbon dioxide emissions have such far-reaching impacts beyond the one we hear about every day--global warming. Luckily, we have plenty of ways to work on global warming and curtail carbon dioxide emissions, such as cement that absorbs carbon dioxide as it hardens, castles that scrub CO2 from the air, and solar power concentrators that generate 1500 times as much energy as regular solar cells, reducing our dependence on fossil fuels.

What's your favorite way to ditch carbon dioxide?

Feb
23
2011

We've written about freaky frogs on the Buzz Blog before, but some recent news may shed new light on our abnormal amphibians. Until recently, researchers thought that atrazine, an agricultural pesticide, was the sole cause of sexual deformities in frogs. Unfortunately, it's not so simple.
UT OH: What lurks in me waters?
UT OH: What lurks in me waters?Courtesy Mike Ostrowski

An ecologist at Yale University, David Skelly, sought to test assumptions about atrazine by studying the frequencies of frog deformity in different land types--agricultural, suburban, urban, and forested. Skelly expected to find the highest rates of deformities in agricultural areas, which would be consistent with atrazine being the main cause. Curiously, he found the highest rates of deformity in urban and suburban areas--places we wouldn't expect to find much atrazine. So what's going on?

It turns out that what makes atrazine so dangerous is that it mimics estrogen and binds to estrogen receptors in frog cells. Because estrogen impacts sexual development and function, so too does atrazine. But atrazine isn't the only estrogen-mimicking compound out there--there's a whole class of chemicals that mimic estrogens, including those found in birth control pills and plastics (BPA). And these chemicals are found in droves in cities and surburban areas--they're flushed into the sewage, but aren't filtered out during water treatment.
Birth control pills: Estradiol, a synthetic estrogen, helps prevent pregnancy in women. But much of it is excreted in urine and eventually makes its way into various water sources.
Birth control pills: Estradiol, a synthetic estrogen, helps prevent pregnancy in women. But much of it is excreted in urine and eventually makes its way into various water sources.Courtesy Ceridwen

So why do we care? Besides the fact that frogs are just awesome little creatures and important parts of their food webs, they have something in common with humans--estrogen receptors. The same chemicals that impact frogs can impact us. So how do we humans keep our sexual development and functioning intact?
BPA-free: This Sigg bottle is made from enameled aluminum, and it's an example of a BPA-free bottle.
BPA-free: This Sigg bottle is made from enameled aluminum, and it's an example of a BPA-free bottle.Courtesy Bucklesman

Skelly had a great idea to filter this stuff out of the water at the treatment plant, so that it won't get into our bodies from drinking water. He also suggested that regulatory changes would help so that when new chemicals are developed, they're scrutinized for unintended side effects. And of course, we can make choices that reduce our exposure, such as by buying BPA-free plastics, or using stainless steel and glass containers. And of course, increased awareness is always a good idea.

Do you take extra steps to avoid things like BPA? What are they?