Tag Archives: Life Science

A single Liter of Seawater Can Hold More Than One Billion Microorganisms

Mat of microbes the size of Greece discovered on seafloor

mighty microbes, which constitute 50 to 90 percent of the oceans’ total biomass, according to newly released data.

These tiny creatures can join together to create some of the largest masses of life on the planet, and researchers working on the decade-long Census of Marine Life project found one such seafloor mat off the Pacific coast of South America that is roughly the size of Greece.

A single liter of seawater, once thought to contain about 100,000 microbes, can actually hold more than one billion microorganisms, the census scientists reported. But these small creatures don’t just live in the water column or on the seafloor. Large communities of microscopic animals have even been discovered more than one thousand meters beneath the seafloor. Some of these deep burrowers, such as loriciferans, are only a quarter of a millimeter long.

“Far from being a lifeless desert, the deep sea rivals such highly diverse ecosystems as tropical rainforests and coral reefs,”
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Microbes help to turn atmospheric carbon dioxide into usable carbon, completing about 95 percent of all respiration in the Earth’s oceans…

Poor Results on Evolution and Big Bang Questions Omitted From NSF Report

Evolution, Big Bang Polls Omitted From NSF Report by Yudhijit Bhattacharjee

The section, which was part of the unedited chapter on public attitudes toward science and technology, notes that 45% of Americans in 2008 answered true to the statement, “Human beings, as we know them today, developed from earlier species of animals.” The figure is similar to previous years and much lower than in Japan (78%), Europe (70%), China (69%), and South Korea (64%). The same gap exists for the response to a second statement, “The universe began with a big explosion,” with which only 33% of Americans agreed.

The USA continues to lag far behind the rest of the world in this basic science understanding. Similar to how we lag in other science and mathematical education. Nearly Half of Adults in the USA Don’t Know How Long it Takes the Earth to Circle the Sun.

Jon Miller, a science literacy researcher at Michigan State University in East Lansing who authored the survey 3 decades ago and conducted it for NSF until 2001. “Evolution and the big bang are not a matter of opinion. If a person says that the earth really is at the center of the universe, even if scientists think it is not, how in the world would you call that person scientifically literate? Part of being literate is to both understand and accept scientific constructs.”

I completely agree. People have the right to their opinions. But those opinions which are related to scientific knowledge (whether it is about evolution, the origin of the universe, cancer, the speed of light, polio vaccinations, multi-factorial designed experiments, magnetic fields, chemical catalysts, the effectiveness of antibiotics against viral infections, electricity, optics, bioaccumulation, etc.) are part of their scientific literacy. You can certainly believe antibiotics are affective against viral infections but that is an indication you are scientifically illiterate on that topic.

2006 NSF chapter that included the results
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South African Fossils Could be New Hominid Species

South African fossils could be new hominid species

The fossils of a female adult and a juvenile male – perhaps mother and son – are just under two million years old. They were uncovered in cave deposits at Malapa not far from Johannesburg.

Researchers tell the journal Science that the creatures fill an important gap between older hominids and the group of more modern species known as Homo, which includes our own kind. The team has assigned the name Australopithecus sediba to their finds.

“It’s at the point where we transition from an ape that walks on two legs to, effectively, us,” lead scientist Professor Lee Berger of the University of the Witwatersrand told BBC News.

“I think that probably everyone is aware that this period of time – that period between 1.8 and just over two million years [ago] – is one of the most poorly represented in the entire early hominid fossil record. You’re talking about a very small, very fragmentary record,” he explained.
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Their bones were laid down with the remains of other dead animals, including a sabre-toothed cat, antelope, mice and rabbits. The fact that none of the bodies appear to have been scavenged indicates that all died suddenly and were entombed rapidly.

“We think that there must have been some sort of calamity taking place at the time that caused all of these fossils to come down together into the cave where they got trapped and ultimately buried,” said team-member Professor Paul Dirks from James Cook University in Queensland, Australia.

All were preserved in the hard calcified clastic sediment that formed at the bottom of a pool of water.

Using Bacteria to Power Microscopic Machines

Scientists at the U.S. Department of Energy’s (DOE) Argonne National Laboratory and Northwestern University have discovered that common bacteria can turn microgears when suspended in a solution, providing insights for designs of bio-inspired dynamically adaptive materials for energy.

“The ability to harness and control the power of bacterial motion is an important requirement for further development of hybrid biomechanical systems driven by microorganisms,” said Argonne physicist and principal investigator Igor Aronson. “In this system, the gears are a million times more massive than the bacteria.”

A few hundred bacteria work together in order to turn the gear. When multiple gears are placed in the solution with the spokes connected as in a clock, the bacteria will turn both gears in opposite directions, causing the gears to rotate in synchrony—even for long stretches of time.

“There exists a wide gap between man-made hard materials and living tissues; biological materials, unlike steel or plastics, are ‘alive,'” Aronson said. “Our discovery demonstrates how microscopic swimming agents, such as bacteria or man-made nanorobots, in combination with hard materials, can constitute a ‘smart material’ which can dynamically alter its microstructures, repair damage, or power microdevices.”

Taste Cells in the Stomach and Intestine

Stomach’s Sweet Tooth

Taste, scientists are discovering, is a whole-body sensation. There are taste cells in the stomach, intestine and, evidence suggests, the pancreas, colon and esophagus. These sensory cells are part of an ancient battalion tasked with guiding food choices
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Newly discovered taste cells in the gut appear to send a “prepare for fuel” message to the body, a finding that may explain a link between diet soda and diabetes risk.
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The gut’s taste cells appear to be built from the same machinery as the taste cells of the tongue, the structures of which scientists have only recently nailed down. Taste cells interact with what are called “tastants” via receptors, specialized proteins that protrude from cell walls and bind to specific molecules drifting by. When a tastant binds to a receptor, it signals other molecules that, in the mouth, immediately send an “accept” or “reject” message to the brain.
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Gut taste cells appear to regulate, in part, secretion of insulin, a hormone crucial for telling body tissues whether they should tap newly arrived glucose or valuable stored fat for energy.

Engineering Mosquitoes to be Flying Vaccinators

Mosquitoes Engineered Into Flying Vaccinators by Emily Singer

Researchers in Japan have transformed mosquitoes into vaccine-carrying syringes by genetically engineering the insects to express the vaccine for leishmaniasis–a parasitic disease transmitted by the sandfly–in their saliva. According to a study in Insect Molecular Biology, mice bitten by these mosquitoes produced antibodies against the parasite. It’s not yet clear whether the immune response was strong enough to protect against infection.

“Following bites, protective immune responses are induced, just like a conventional vaccination but with no pain and no cost,” said lead researcher Shigeto Yoshida, from the Jichi Medical University in JapanYoshida, in a press release from the journal. “What’s more continuous exposure to bites will maintain high levels of protective immunity, through natural boosting, for a life time. So the insect shifts from being a pest to being beneficial.”

Researchers consider the project more of a proof of principle experiment than a viable public health option, at least for now.

Very cool.

Invisible Worlds: Fastest Thing on the Planet

Fun with Fungi.

Antibiotics Breed Superbugs Faster Than Expected

We continue to endanger ourselves by using antibiotics inappropriately. This is one of many things that happen when the public at large is ignorant about science and ignores scientific evidence. I don’t believe people want to put other people’s lives in danger. But our behavior in the face of the evidence has us doing just that. I believe because we don’t value science rather than because we don’t care about putting others (and ourselves) in danger. Antibiotics Breed Superbugs Faster Than Expected

Bacteria don’t just develop resistance to one drug at a time, but to many — and at accelerated rates. That’s because antibiotics boost bacterial production of free-radical oxygen molecules that damage bacterial DNA. Repairs to the DNA cause widespread mutations, giving bacteria more chances to randomly acquire drug-resistant traits.
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Drug resistance is a serious public health concern. According to the federal Centers for Disease Control and Prevention, 70 percent of 1.7 million infections acquired in hospitals every year are resistant to at least one drug. Those infections annually kill 99,000 Americans — more than double the number that die in car crashes.

Drugs that once destroyed almost any bacteria now kill only a few, or don’t work at all. In the case of some drugs, like Cipro, the decline is dramatic: Where in 1999 it worked against 95 percent of E. coli, it treated only 60 percent by 2006. Against lung infection-causing Acinobacter, its effectiveness fell by 70 percent in just four years.

Though drug resistance is ultimately inevitable, conventional wisdom holds that antibiotics consumed at suboptimum doses hasten the process. Bugs that would have succumbed to a larger dose live to multiply, pushing the strain as a whole closer to resistance. That happens when a prescription goes unfinished, or when antibiotics used on farms enter food and water at low levels.
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Of the 35 million pounds of antibiotics consumed annually in the United States, 80 percent goes to farm animals. Much of it is used to treat diseases spread by industrial husbandry practices, or simply to accelerate growth. As a result, farms have become giant petri dishes for superbugs, especially multidrug-resistant Staphylococcus aureus, or MRSA, which kills 20,000 Americans every year – more than AIDS.

Alarming cases of farm-based MRSA and other diseases led to a proposed Congressional law restricting the use of agricultural antibiotics. That bill, supported by the American Medical Association and American Public Health Association, is opposed by farm lobbyists and remains stuck in committee.

Researchers Explain How Rotifers Thrive Despite Forgoing Sex

Bdelloid rotifers haven’t had sex for at least thirty million years. Most asexual animals are doomed to extinction. The excellent show, Science Friday, looks at the extraordinary adaptations that allow rotifers to thrive sex-free.

For millions of years, the rotifers have reproduced asexually, flying in the face of an idea known as the Red Queen Hypothesis, which states that without the advantage of sexual reproduction, more-rapidly evolving parasites and predators will eventually doom the asexual species. Now, the researchers studying the tiny organism say that its ability to dry up and blow away to greener pastures may have given the rotifers a hidden tactical edge in this evolutionary war.

The webcast provides a nice overview of the research. Every week Science Friday provides many such interesting reviews of recent scientific research.

What Are Rotifers?

Rotifers are small, mostly freshwater animals, and are amongst the smallest members of the Metazoa — that group of multicellular animals which includes humans, and whose bodies are organized into systems of organs.
Most rotifers are about 0.5mm in length or less, and their bodies have a total of around a thousand cells. This means that their organ systems are a greatly simplified distillation of the organ systems found in the bodies of the higher animals.

A typical rotifer might have a brain of perhaps fifteen cells with associated nerves and ganglia, a stomach of much the same number, an excretory system of only a dozen or so cells, and a similarly fundamental reproductive system. They have no circulatory system. It is an anomaly that despite their complexity, many rotifers are much smaller than common single-celled organisms whose world they share.
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they are able to survive long periods — even perhaps hundreds of years — in a dried or frozen state, and will resume normal behaviour when rehydrated or thawed.
Secondly, they exhibit what biologists call cell constancy — they grow in size not by cell division, but by increase in the size of the cells which they already have.

Researchers Find Switch That Allows Cancer Cells to Spread

Researchers discovered of a specific protein called disabled-2 (Dab2) that switches on the process that releases cancer cells from the original tumor and allows the cells to spread and develop into new tumors in other parts of the body.

The process called epithelial-mesenchymal transdifferientiation (EMT) has been known to play a role in releasing cells (epithelial cells) on the surface of the solid tumor and transforming them into transient mesenchymal cell: cells with the ability to start to grow a new tumor.

This is often the fatal process in breast, ovarian, pancreatic and colon-rectal cancers.

Searching to understand how the EMT process begins, Ge Jin, who has joint appointments at the Case Western Reserve University School of Dental Medicine and the Lerner Research Institute at the Cleveland Clinic, began by working backwards from EMT to find its trigger. The researchers found that a compound called transforming growth factor-ÃŸ (TGF-ÃŸ) triggers the formation of the Dab2 protein. It was this protein, Dab2, that activated the EMT process.

He discovered that when the researchers knocked out Dab2, EMT was not triggered. “This is the major piece in cancer research that has been missing,” Jin said. Most tumors are epithelial in origin and have epithelial markers on their surface. The EMT process takes place when some of those cells dislodge from the surface and undergo a transformation into a fibrous mesenchymal cell maker with the ability to migrate.

“EMT is the most important step in this process,” said Jin. He was part of a six-member research team, led by Philip Howe from the Department of Cancer Biology at the Lerner Research Institute in a National Institute of Cancer-funded study. The research group studied the biological processes that initiated the cancer spread by using cancer cells in animal models.

“If we can understand the signaling pathway for modulating EMT, then we can design drugs to delay or halt EMT cells and control tumor progression,” Jin said. Beyond cancer, Jin said. “The process we discovered may lead to understanding how other diseases progress.”