science news

Mitch on TV (again!)

As mentioned in the previous entry, Mitch was recently featured on TV for his contribution to research, awareness and chemical education. Because of his awesomeness (and the nature of network TV), American Latino TV plans to rerun the interview this weekend! Woot! Again, for local listing, check out this page.

When this was first aired, we had a pizza party at Mitch’s place with a bunch of friends. There was never a dull moment in the short but entertaining segment. Let me assure you that this is totally worth watching. This is such an embarrassment for Mitch, complete with goggles, lab coat, baby pictures, and obviously his awesome undergraduate minions. But obviously, it’s the baby pictures that made it all worthwhile.

Hopefully the clip will be available online soon for our friends and readers worldwide. 🙂


By June 5, 2008 2 comments science news

Irradiation to enhance food safety

Does anyone remember the E. Coli breakout back in 2006? I do. There has never been a quicker way to convince a 19-year-old to eat vegetables until you take lettuce out of their sandwiches for a couple of months.

According to the LA Times report[1], these greens are washed in potent chlorine bath, often up to three times, before they are bagged and shipped to the retailer. This standard procedure has a reported 90% effectiveness in killing the microorganisms that may cause harmful effects to the human body.

I don’t know about you, but I would rather not take that 10% chance to get sick. In the single breakout of E. Coli due to cross contamination with the cattle back in 2006, 200 people became ill and three lost their lives. That’s the 10% chance that nobody should have to take.

This past month at the ACS National Meeting in New Orleans, researchers from the USDA presented their findings and results of radiation treatment of fresh produces. Irradiation of high energy beams of photons or electrons, said the scientist, can disrupt the DNA of these pathogens. While the chlorine rinse offers a 90% effectiveness in killing bacterias on the surface of the leaves, it is not able to penetrate beneath the surface. Irradiation method has a reported >99.9% effectiveness in wiping out pathogens such as E. coli, salmonella and listeria, and the high energy beams allows penetrating power that works inside and outside the leaves.

Some members of the scientific community are calling irradiation one of the “few intervention steps that indeed can penetrate the leaf surface and kill microorganisms.”

Irradiation for enhancement of food safety is permitted for some hamburger meat, poultry and spices, but not for fruits and vegetables. However, there has not been any health problems associated with eating irradiated food. So why is FDA steering away from adopting an improved method that could potentially save lives?

Consumer experts and food safety researchers offer some of their speculations:

1. Irradiation may damage the apparence of the product, which may not be as appealing to the customers
2. Nobody would buy lettuce from a bag with a radiation sticker
3. The treatment could shorten shelf lives of the products
4. Technically, irradiated produces cannot be certified organic

Though reasonable, it is hard to believe that the above mentioned points would stop either FDA or independent research institutes from further investigating in a method that could possibly be so much more potent in eradicating pathogens than the existing practice. Perhaps these novel ideas would not suffer as much if we could deliver more transparent and correct ideas regarding the applications of radiation.

Using innovative ideas to improve the quality of our everyday lives, isn’t that what science is all about?


[1] USDA scientists say irradiation could be key to food safety

P.S. True to scientific spirit and for the benefit of the minorities out there, I will summarize and translate my discussion in lolcat. I can has radeashuns: on ur vegitablez, keelin ur baktiriaz.

Edit: Originally mentioned by Bethany Halford and Lisa Jarvis in Chemistry Newsbytes.

By April 22, 2008 9 comments nuclear chemistry, science news

Mitch on TV

Tune in to cheer on for our beloved blogger, Mitch, for his television debut this weekend. He will be featured on American Latino TV as an outstanding member of the cultural community. In this interview, he will be talking about how he chose the path as a nuclear chemist, and his aspiration to educate today’s youth on chemistry using the internet.

A complete listing of available channel can be found on this page:

By April 17, 2008 7 comments science news

Strained Acetylenes for Click-Chemistry

This ACIE article caught my attention. Here, a “click-chemistry” based approach is used for in vivo labeling of glycoproteins. The strained acetylene 1 is linked to biotin to give 2. Cells that have been cultured in a way as to introduce N-azidoacetylsialic acid into glycoproteins were exposed to acetylene 2, then stained with avidin-FTIC (this is a fluorescein-labeled protein with a very high affinity for biotin). As a result, the glycoproteins at the cell surface fluoresce.


What happens chemically is a [3+2]-cycloaddition of the azido-substituted sialic acid (Sia) to the acetylene to give 3. The special thing here is the absence of copper(I), which would be cytotoxic and is normally required as a cycloaddition catalyst. Instead, the addition runs without any metals because of the strain of the eight-membered ring.

This also reminds me of Sharpless’ work for the fragment-screening of HIV-1 protease inhibitors (e.g. this ACIE article). He also used the [3+2]-cycloaddition with inhibitor fragments containing azido and acetylene groups. The fragments would effectively add in situ, i.e. inside the binding site, to form strong inhibitors. Here, the enzyme itself acts as a catalyst or template by arranging the most suitable fragments in a favourable orientation.

By February 22, 2008 7 comments science news