Stories tagged Cells
Earth, our place in spaceCourtesy NASALife 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 systemCourtesy C-MOREYoung 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.
ProchlorococcusCourtesy Dr. Anne Thompson, MITEven 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.
Tags : It seems that there has been a bit of a kerfuffle about this paper in the Journal of Cosmo
Cyanobacteria: Could cells like these have been found in space rocks?Courtesy Microbial Diversity, Rolf Schauder and David Graham, © 1997logy, 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...
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.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?
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?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.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.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?
ocean micro-plastic: These samples were collected from the surface water of the North Pacific Ocean by the SUPER expedition in 2008.Courtesy C-MOREWho hasn’t heard that plastic in the ocean is trouble?
- Plastic has been found clogging the stomachs of dead albatross and other ocean birds.
- Plastic ropes and traps have entangled marine life, causing more death.
- As a long-lasting chemical, plastic floating in the ocean provides long-distance rafts that may move aggressive alien marine life to new areas.
- Plastic may provide a “sticky” surface where toxins can accumulate, becoming a concentrated source of poison for marine consumers.
- A "Great Pacific Garbage Patch" has been reported to be an "island the size of Texas" floating in the North Pacific Ocean...but is this really true? Continue reading to find out!
Yep, plastic in the ocean is bad news; so let’s put scientific energy into studying and solving the problem.
manta trawl: The trawl is hoisted above the stern deck of the RV Kilo Moana.Courtesy C-MOREIn 2008 C-MORE, the Center for Microbial Oceanography: Research & Education headquartered at the University of Hawai`i, with assistance from the Algalita Marine Research Foundation, embarked on an oceanographic expedition aboard the RV Kilo Moana, which means "oceanographer" in Hawaiian. The goal of the expedition, dubbed SUPER (Survey of Underwater Plastic and Ecosystem Response Cruise), was to measure the amount of micro-plastic in the ocean. In addition, oceanographers took samples to study microbes and seawater chemistry associated with the ocean plastic. The Kilo Moana sailed right through the area known as the “Great Pacific Garbage Patch,” between Hawai`i and California.
Early results: there was no garbage patch/island. Once in a while something like a barnacle-covered plastic buoy would float past the ship, but mostly the ocean looked really clean and empty of any kind of marine debris.
manta trawl: The net is being pulled slowly through the ocean's surface water.Courtesy C-MOREBut wait! Scientists looked closer and were amazed. Every single one of the more than a dozen manta trawls, filtering the surface seawater for an hour and a half each, brought up pieces of micro-plastic! Some were as small as 0.2 millimeter, mixed among zooplankton!
Other expeditions have reported similar results (for example, Scripps Institution of Oceanography's 2009 SEAPLEX expedition and Sea Education Association's North Atlantic Expedition 2010): no Texas-size garbage patches, but plenty of plastic marine debris to worry about. The data seem to show that most of the plastic is in the form of small pieces spread throughout upper levels of water at some locations around the world's ocean. In these areas, the ocean is like a dilute soup of plastic.
Dr. White: examining the results of a manta towCourtesy C-MOREC-MORE researcher Dr. Angelicque (Angel) White, assistant professor of oceanography at Oregon State University (OSU) was a scientist on board the SUPER expedition. In recent interviews, (for example: the Corvallis Gazette-Times and Seadiscovery.com) Dr. White cautions us to view the complex plastic marine debris problem accurately. Furthermore, new results will soon be published by C-MORE about microbial diversity and activity on plastic pieces.
In the meantime, as Dr. White says, “…let’s keep working on eliminating plastics from the ocean so one day we can say the worst it ever became was a dilute soup, not islands. “
Plastic in the ocean is trouble. How can you be part of the solution?
This Wednesday evening kicks off a super-exciting four-part NOVA series about nanotechnology called Making Stuff. Each episode focuses on one general concept: stronger, smaller, cleaner, smarter. We could just squeal.
Spider Web +Courtesy National Science Foundation
I was honored to get a sneak-preview of the first episode, Making Stuff: Stronger in San Francisco in October, and found myself in some crazy conversations afterward about bioengineering and media ethics. You see, scientists have, uh, installed spider silk-making genes into goats, thereby making the goat milk spinnable into spider silk. The Making Stuff episode covers this, then ends by showing the host happily drinking a glass of milk, and we’re left wondering if it's actually the spider-silk-milk that he’s downing without a care in the world.
Baby Goat =Courtesy National Science Foundation
2020 Science, the blog of Andrew Maynard, scientist, science policy guru, and Director of the Risk Science Center at the University of Michigan School of Public Health, kindly takes the conversation beyond “ew!” to “responsible?” Andrew was also in the room for the special preview, and raised far more eloquent concerns than I (I’m sorry – I’m still stuck on the spiders…ew), and then blogged about them. And then got substantive responses, including one from Making Stuff’s producer, Chris Schmidt. All a fascinating read.
Andrew, being the smart, informed fellow that he is, pointed out that this whole spidergoat concept is old news. 
Bioengineered Spider SilkCourtesy National Science FoundationNo less icky and/or creepy I would add, but still old news. Can’t wait until the Making Stuff episode that delves into the topic on Wednesday? Take a peek at the short video put together by the National Science Foundation.
Surveying Microbes at SeaCourtesy C-MOREThere are microbes…and then there are micro-microbes. Oceanographers on C-MORE’s BiG RAPA oceanographic expedition are finding bacteria the size of one-one-millionth of a meter in the oligotrophic (low nutrient), open-ocean of the Southeast Pacific, far from the productive waters off the coast of Chile. But that’s not all; some scientists are looking for the even smaller marine viruses in gallons of filtered seawater. Meet some of these micro-microbes in these video reports:
ProchlorococcusCourtesy Dr. Anne Thompson, MIT
- Microbe Diversity, Part 1: Prochlorococcus, the most common bacterium in the world’s oceans; nitrogen-fixing bacteria that provide a usable form of nitrogen “fertilizer” for other photosynthesizers
- Microbe Diversity, Part 2: picophytoeukaryotes with different colored pigments; viruses, which are parasites on other living things
Yes indeed, microbial oceanographers are taking home quite a collection from the South Pacific Ocean. In less than a week the good ship RV Melville will arrive at Rapa Nui (Easter Island), and scientists will step onto land for the first time in almost a month. They and their oceanographic samples will return to C-MORE laboratories around the U.S. The oceanographers are also returning with new hypotheses buzzing around in their heads. Now it’s time for them to take the next step in the Scientific Method: data analysis!
surveying microbes at seaCourtesy C-MOREDr. Dan Repeta from the Woods Hole Oceanographic Institution (WHOI) is C-MORE’s Chief Scientist on the BiG RAPA expedition, which is conducting research off the coast of Chile. Dr. Repeta and his team of scientists are sampling the underwater microbial environment using a variety of instruments, including a water collector called a CTD (see educational resource below). Two interesting results have turned up in the CTD data:
- chlorophyll -- The greatest amount of the green pigment, representing floating microscopic plants in the sea known as phytoplankton, was found about 30 meters below the sea surface. (That's where oceanographers expect the most chlorophyll. Perhaps phytoplankton living at that depth must produce more chlorophyll in order to capture the lower light intensities, just like leaves are usually darker green if they're growing on a land plant in the shade). However, a surprise awaited oceanographers at 60 meters. At that depth, they discovered an unusual “secondary, deeper chlorophyll max," something not seen many other places in the world.
- Oxygen -- This gas enters the ocean primarily at the surface, from the air and also from phytoplankton photosynthesis. Bacteria and other heterotrophs consume the O2 as they metabolize. Therefore, oxygen is expected to decrease with depth. At BiG RAPA's Station 1 oxygen not only fell; it fell all the way to near zero.
Dr. Angel White and the CTDCourtesy Eric Grabowski, C-MORE"Sea It Live" in some BiG RAPA videos. Join Dr. Angel White from Oregon State University as she demonstrates the CTD rosette. Then join Dr. Repeta for his Chief Scientist Station 1 Update .
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*Educational resource = C-MORE Science Kit Ocean Conveyor Belt's Powerpoint, "Lesson 3: Using Data to Explore Ocean Processes "
Glowing TreesCourtesy This image, which was originally posted to Flickr, was uploaded to Commons using Flickr upload bot on 09:48, 21 July 2008 (UTC) by Manoillon (talk). On that date it was licensed under the Creative Commons Attribution 2.0 Generic license.Bioluminescence. Think fireflies. Or anglerfish. Or your friendly neighborhood boulevard tree. Wha? Yep. Recently the Royal Society of Chemistry published (and gave their royal thumbs-up to) Dr. Yen-Hsun Wu’s paper in which he describes eliminating the need for energy-sapping streetlights by injecting trees with gold nanoshells.
According to inhabitat (design will save the world):
By implanting the gold nanoparticles into the leaves of the Bacopa caroliniana plants, the scientists were able to induce the chlorophyll in the leaves to produce a red emission. Under a high wavelength of ultraviolet light, the gold nanoparticles were able to produce a blue-violet fluorescence to trigger a red emission in the surrounding chlorophyll.
Popular Science is just as psyched:
This ingenious triple threat of an idea could simultaneously reduce carbon emissions, cut electricity costs and reduce light pollution, without sacrificing the safety that streetlights bring.
Creepy? Cool? You decide.
All Abooooooard! Microbes Set SailCourtesy C-MOREWell, yeah, that’s right. Microbes don’t smile, and they sure don’t command an oceanographic ship. However, there are lots of microbes in the sea; in fact, they account for most of the total marine biomass. With that in mind, there’s no question about microbes being fundamental to the functioning and health of the oceans.
UNOLS ship, the RV MelvilleCourtesy Scripps Institution of OceanographyScientists from C-MORE (Center for Microbial Oceanography: Research and Education) and the Universidad de Concepción, Chile have organized an expedition to one of the most sparsely sampled oceanic regions on the planet…the southeast Pacific Ocean. The expedition’s official name is BiG RAPA (Biogeochemical Gradients: Role in Arranging Planktonic Assemblages). It departed from Chile on November 17 on the research ship Melville and will travel almost due west, ending at Rapa Nui (Easter Island) on December 14.
BiG RAPA expedition’s multi-media, interactive Sea It Live websiteCourtesy C-MOREOceanographers will conduct studies on a microbial community that exists in a very curious environment. The Melville will travel from the nutrient-rich coastal waters off Chile into the low-nutrient area known as the South Pacific Subtropical Gyre. The SPSG is the most oligotrophic, or nutrient-poor, of all sub-tropical gyres. What kind of microbes can live in such an impoverished area? How do they do it? Join the BiG RAPA’s Sea It Live Tracker and find out!
