Category Archives: Life Science

Why does orange juice taste so bad after brushing your teeth?

Why does orange juice taste so bad after brushing your teeth? Ok, those that have never experienced this go try it. You will discover why I still remember learning that orange juice and toothpaste didn’t mix when I was a kid. Isn’t it great that I can stumble across answers to questions I had forgotten I asked 🙂

David Cannell is the scientific spokesperson for Questacon, “It’s because of a certain ingredient in toothpaste called sodium laurel sulfate. It actually blocks sweet sensors. All the other taste bud cells in your mouth are firing away nicely, but the receptors which pick up the sweet sensors are not working anymore. Not only does it block the sweet sensors, it enhances the sour and bitter, so you get this massive influx of sour and bitter taste coming through the mouth.”

David says tastebuds are a very interesting part of the body, “They’re the little bumps on the top of your tongue. They look like a tiny onion, if you look at it with a high powered microscope. Each tastebud, which we have about ten thousand of, has about fifty different taste cells.”

Just imagine what we will find with the better internet that China is building?

Lab on a Chip Blood Tests

Portable ‘lab on a chip’ could speed blood tests:

Within the lab on a chip, biological fluids such as blood are pumped through channels about 10 microns, or millionths of a meter, wide. (A red blood cell is about 8 microns in diameter.) Each channel has its own pumps, which direct the fluids to certain areas of the chip so they can be tested for the presence of specific molecules.

Until now, scientists have been limited to two approaches to designing labs on a chip, neither of which offer portability. The first is to mechanically force fluid through microchannels, but this requires bulky external plumbing and scales poorly with miniaturization.

The second approach is capillary electro-osmosis, where flow is driven by an electric field across the chip. Current electro-osmotic pumps require more than 100 volts of electricity, but the MIT researchers have now developed a micropump which requires only battery power (a few volts) to achieve similar flow speeds and also provides a greater degree of flow control.

Antibiotic Research

anti-microbial ‘grammar’ posits new language of healing

“In the last 40 years, there have been only two new classes of antibiotic drugs discovered and brought to the market,” said graduate student Christopher Loose, lead author of a paper on the work that appears in the Oct. 19 issue of Nature. “There is an incredible need to come up with new medicines.”
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focusing their attention on antimicrobial peptides, or short strings of amino acids. Such peptides are naturally found in multicellular organisms, where they play a role in defense against infectious bacteria.

See previous post on the paucity of new antibiotic discoveries

Complete Work of Charles Darwin Online

Complete Work of Charles Darwin Online – The University of Cambridge has done a much better job of use the web effectively than some others: Classic Botanical Illustrations Presented Poorly. The site includes 50,000 pages and 40,000 images (publications and handwritten manuscripts), including, of course, Origin of Species. Fantastic stuff.

Life Untouched by the Sun

Gold mine holds life untouched by the Sun

The first known organisms that live totally independently of the sun have been discovered deep in a South African gold mine.

The bacteria exist without the benefit of photosynthesis by harvesting the energy of natural radioactivity to create food for themselves. Similar life forms may exist on other planets, experts speculate.

The bacteria live in ancient water trapped in a crack in basalt rock, 3 to 4 kilometres down. Scientists from Princeton University in New Jersey, US, and colleagues analysed water from the fissure after it was penetrated by a narrow exploratory shaft in the Mponeng gold mine near Johannesburg, South Africa. The shaft was then closed.

I must say I was confused why this was seen as the “first” such life.

Other sulphate-eating bacteria have been found in ocean sediments, volcanoes and oil deposits. But all have either received some chemicals produced by photosynthesis, or it has not been clear whether they were trapped and dying, or flourishing.

I am still not sure the “first” claim is really accurate (from NASA site in 2001), but nevertheless this is another interesting case of extremophiles.

Related: Bacteria Living in Glacier

Cancer-Killing Virus

Scientists Say Cancer-Killing Virus Developed (site broke the link so I removed it)

South Korean scientists have said they have developed a new genetically altered strain of virus which is highly efficient in targeting and killing cancer cells. The new therapy developed by the team from Yonsei University uses a genetically-engineered form of the adenovirus, which normally causes colds.

The adenovirus was implanted with a human gene that is related to the production of relaxin, a hormone associated with pregnancy. When injected into cancerous tumors, the virus quickly multiplies in the cancer cells and kills them, the team said.

There are many more wonderful announcements than wonderful treatments. Still this is one in the long line of potentially wonderful treatments. If it turns out to be successful the whole world will benefit. That we all will benefit from such breakthroughs is why I am glad so many countries are investing in science and engineering (also see: Worldwide Science and Engineering Doctoral Degree Data).

CDC Urges Increased Effort to Reduce Drug-Resistant Infections

The US Center for Disease Control has again urged hospitals to increase efforts to reduce drug-resistant infections. In 1972, only 2 percent of these types of bacteria were drug resistant. By 2004, 63 percent of these types of bacteria had become resistant to the antibiotics commonly used to treat them, and methicillin-resistant “staph” infections, often referred to as MRSA, are a growing problem. The CDC press release. This press release is focused on reducing the transmission of such dangers bacteria to patients. Other CDC efforts focus on improving the system to reduce the production of such virulent bacteria.

I know the Pittsburgh area has done a fair amount of work in the reduction of MRSA transmission. Several white papers on their efforts are available. A great PBS documentary covers this and other health care improvements.

Inside Live Red Blood Cells

Technique reveals inner lives of red blood cells:

For the first time, researchers at MIT can see every vibration of a cell membrane, using a technique that could one day allow scientists to create three-dimensional images of the inner workings of living cells.
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Soon, the researchers hope to extend their view beyond the cell membrane into the cell, to create images of what is happening inside living cells — including how cells communicate with each other and what causes them to become cancerous.

“One of our goals is create 3D tomographic images of the internal structure of a cell,” said Michael Feld, MIT professor of physics and director of the Spectroscopy Lab. “The beauty is that with this technique, you can study dynamical processes in living cells in real time.”

Example of what that will look like: The Inner Life of a Cell – Animation – ok actually that level of detail may still be fairly far away 🙂

The World’s Smallest Genome

The World’s Smallest Genome Just Got Smaller by Joe Palca:

Scientists used to think the number was around 300, but now researchers have found a bacterium that gets by with only 182 genes. The bacteria live inside tiny insects called psyllids. Researchers posit that the bacterium is in the evolutionary process of becoming a part of the insect.

Some of the smallest bacterial genomes are in bacteria that have what is called a symbiotic relationship with a host. The bacteria make something the host needs, and the host can take care of many of the bacteria’s biological needs.
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Johnson says most scientists believe that cells of higher organisms achieved their lofty status by enslaving bacteria that gave up a few too many genes. For example, our cells have something in them called mitochondria. Mitochondria are known as the power plants inside cells.

Johnson says mitochondria were once bacteria that lost too many genes.

“Of course, these events occurred a very, very long time ago,” she says, “and what I think is extremely exciting about this new research is that we might be seeing this happen in real time.”

There is so much interesting science and so little time to absorb it.

Hawaiian Jellyfish

Video of Jellyfish find in Hawaii