Category Archives: Life Science

Science Fair Project on Bacterial Growth on Packaged Salads

Recently we have all seen quite a few stories on – Tainted spinach: All bacteria may not come out in the wash. Last year a high school student did her science projected on the problem. Hillel Academy student first tested spinach for science fair by Stacey Dresner

“Last year I heard some rumors going around about how some people were getting sick and scientists thought that the illness was coming from these convenient packaged salads,” explained Kaili, now a ninth grader at the Hebrew High School of New England in West Hartford. “This caught my attention and I decided that I wanted to look more into the issue for my science fair project.”
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In her project, “Quantitative Analysis of Bacterial Growth on Packaged Salads and Effect on Antibiotic Resistance and Nutrient Content,” Kaili investigated several varieties of bagged salad greens.

She tested the bagged greens for bacteria content, and found “extensive growth of bacteria within 24 hours in the fresh “unwashed” samples.”

“I found the highest percents of bacteria in dark, leafy varieties such as spinach and Mediterranean” showing “a correlation between high levels of iron and high levels of bacteria.”

She washed the samples using different cleaning techniques n cleaning with sterile water, cooking with boiling water for five minutes, and using commercial cleaning rinse n water with a pinch of bleach. The only method that killed most of the bacteria was the commercial rinse. The others did not really inhibit bacterial growth.

China’s Gene Therapy Investment

We have recently added a new blog to our offerings: the Curious Cat Investing and Economics Blog. For those of you interested in those topics I hope you will give it a try.

Our favorite economics radio (pre-podcast technology) show is Marketplace from National Public Radio. Today they have a story on China’s commitment to gene therapy as a economic strategy to get in on a potentially huge market: China bounds ahead in gene therapy.

This is happening at a time of conservatism toward gene therapy in the United States. Investment in the U.S. slowed after an 18-year-old Pennsylvania boy died in a gene therapy trial seven years ago. His parents filed a lawsuit. The Food and Drug Administration put other trials on hold.
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Patients in China are less likely to file lawsuits, and Chermak says Chinese regulators are more open-minded to new treatments. They see the slowdown in the United States as an opportunity to get ahead.

At the same time, a lot of Chinese researchers who studied in the U.S. are returning home because in China, you can get much more bang for your research buck.

This is an example of the future we discuss in: Diplomacy and Science Research

Jaguars Back in the Southwest USA

photo of jaguar at night in Arizona

Gone for Decades, Jaguars Steal Back to the Southwest

Jaguars are the largest native American cat. They once roamed much of the Southwest, but when ranchers took cattle to the region in the last century, the jaguars were trapped and hunted to extinction in the United States. The last known resident female was killed in 1963 near the Grand Canyon.

Jaguars were thought to be gone from the Southwest until Warner Glenn, a cattle rancher and mountain lion hunter, saw a live one in the Peloncillos Mountains, near the New Mexico border with Mexico, on March 7, 1996.

Story and cool photo by the NY Times. Related: Big Cats in America – The Cat and a Black Bear – Cat Family Tree

Why the Frogs Are Dying

photo of blue poison frog

Why the Frogs Are Dying by Mac Margolis (photo is of a Blue Poison Frog):

A study by 75 scientists published earlier this year in the journal Nature estimated that two thirds of the 110 known species of harlequins throughout Central and South America have vanished. And that may be just the beginning.
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Scientists monitoring wildlife around the world are echoing Pounds’s research. Their conclusion: many more species will perish.

This article does a good job of discussing the interactions caused by global warming and the consequences to some animal species.

2006 Nobel Prize in Physiology or Medicine

The Nobel Prize in Physiology or Medicine 2006 goes to: Andrew Z. Fire and Craig C. Mello for their discovery of
RNA interference – gene silencing by double-stranded RNA.

This mechanism, RNA interference, is activated when RNA molecules occur as double-stranded pairs in the cell. Double-stranded RNA activates biochemical machinery which degrades those mRNA molecules that carry a genetic code identical to that of the double-stranded RNA. When such mRNA molecules disappear, the corresponding gene is silenced and no protein of the encoded type is made.

RNA interference occurs in plants, animals, and humans. It is of great importance for the regulation of gene expression, participates in defense against viral infections, and keeps jumping genes under control. RNA interference is already being widely used in basic science as a method to study the function of genes and it may lead to novel therapies in the future.

The Nobel Prize site also includes does a great job by including advanced information on this work.

Another Strike Against Cola

This is definately not the year of Cola. This summer has seen many stories on Drinking Soda and Obesity. High visability attempts to rid schools of Cola have grown. And now news that, Drinking cola may increase risk to women’s bones

A study of 2,500 people concluded that drinking the carbonated beverages was linked with low bone mineral density in three different hip sites in women, regardless of age, menopausal status, calcium and vitamin D intake and use of cigarettes or alcohol.

Similar results were seen for diet pop and less strongly for decaffeinated pop.

In men, there was no link with lower bone mineral density at the hip, and both sexes showed no link for the spine.

As with most medical studies one big conclusion from this study: more study is needed. While this may be frustrating it is still true, it is not easy to get a full picture of health effects, see: Medical Study Results Questioned. So from some results (with varying degrees of confidence) experts can give the best advice they can and seek to better understand the situation with more studies.

$10 Million X Prize for DNA Decoding

X Prize for Genomics

The $10 million X PRIZE for Genomics prize purse will be awarded to the first Team that can build a device and use it to sequence 100 human genomes within 10 days or less, with an accuracy of no more than one error in every 10,000 bases sequenced, with sequences accurately covering at least 98% of the genome, and at a recurring cost of no more than $10,000 per genome.

Monarch Travels

Fly Away Home:

The butterfly that goes from Canada to Mexico and partway back lives six to nine months, but when it mates and lays eggs, it may have gotten only as far as Texas, and breeding butterflies live only about six weeks. So a daughter born on a Texas prairie goes on to lay an egg on a South Dakota highway divider that becomes a granddaughter. That leads to a great-granddaughter born in a Winnipeg backyard. Come autumn, how does she find her way back to the same grove in Mexico that sheltered her great-grandmother?

A great question and interesting science. Students can help track the monarchs and other migrating species (bald eagles, robins, hummingbirds, whooping cranes…).

To test their ability to reorient themselves, Dr. Taylor has moved butterflies from Kansas to Washington, D.C. If he releases them right away, he said, they take off due south, as they would have where they were. But if he keeps them for a few days in mesh cages so they can see the sun rise and set, “they reset their compass heading,” he said. “The question is: How?”

Discoveries by Accident

‘Failed’ experiment produces a bacterial Trojan horse by Katie Weber. Interestingly the usefulness of Penicillin, the most popular bacteria fighting agent, was discovered by accident (and then a smart scientist learning from the accident and applying that knowledge to creating an incredibly useful medication).

As he was puzzling out why what should have been a routine procedure wouldn’t work, he made a discovery that led to the creation of a new biological tool for destroying bacterial pathogens – one that doesn’t appear to trigger antibiotic resistance.

The discovery also led to the startup of a promising new biotechnology firm that has already brought Wisconsin a dozen new, high-paying, highly skilled jobs.

This is yet another example of the power of scientists and engineers to boost the economy and society at large.

2006 Nikon Small World Photos

photo of Transgenic Nicotiana benthamiana plant

Photos (left, Transgenic Nicotiana benthamiana plant. right, Diatom – unicellular algae) from the from the 2006 Nikon Small World Photomicrography Competition. The deadline for next year is April 30, 2007.