Bio-Based Ideas

After spending the last few blog posts on different aspects of dissimilatory bacteria , I want to switch the focus to a different class of organisms I have been interested in for a long time now. These are the algae. Algae comprise a large diversity of "sea weeds" and an even larger variety of single-celled organisms that mostly are capable of doing photosynthesis. They include the ordinary sea-weed, and make up a portion of the green slime found around the edges and the bottom of a pond. More exotic types of algae can live symbiotically - that is together with another organism in a mutually beneficial way. Lichens are an example of symbiotic relationship between algae and fungi. More information about the evolution and lineage of algae can be found in this wiki article . Image via Wikipedia Typically, these organisms are either not mentioned at all or only in conjunction with toxic algal blooms. But lately, algae, of course, have been in the news recently because of the p...

In the last part, we covered a important way of how bacteria communicate to each other through quorum sensing . The LuxI-LuxR system describes an interesting signaling system used by bacteria of the same species. Professor Bassler's laboratory is especially known for her work on autoinducer 2 (AI-2) system which allows for inter-species communication. The discovery of AI-2, and its fundamental workings were a true scientific detective stories with twists and turns, and its implications are still being researched today. Work on a different luminescent marine bacterium, Vibrio harveyi , revealed that regulatory apparatus for creating luminescent was more complex. It relied on two separate input signals: AI-1 and AI-2 which were recogized by two membrane spanning receptor kinases LuxQ and LuxN respectively. How AI-1 and AI-2 are involved for luminescence may be less important here except to say that both signals need to be present. While more information could be inferred about AI...

Though many talks are interesting, once in a while there comes a talk in a graduate student's life that is so inspiring in both content and presentation. Today was one of these days. I attended the the "Intersectional Seminar Series" here at USC which is a seminar series meant to bring the different separate biology programs - Molecular and Computational Biology, Marine and Environmental Biology, Integrative and Evolutionary Biology and Neurobiology -together. Today's speaker was Bonnie Bassler from Princeton, and her talk title was "Eavesdropping on Bacterial Conversations". Today's blog entry is dedicated to the rich history of ideas she discussed in her talk. I apologize in advance to the longer than usual post and the higher than usual complexity as I try to accurately report back the ideas discussed in her talk. To most lay people, the idea that simple, single-celled bacteria could use sophisticated means of communication may seem rather strange. ...

Last time, we explored how dissimilatory bacteria can be used to generate electricity in devices called Microbial Fuel Cells. In part one, I mentioned that the dissimilatory properties of bacteria like Shewanella can potentially also be used for solving part of the problem of radioactive uranium contaminations. When I mentioned this idea to my friend who is a soil scientist, I realized that I did not know how these bacteria can be used to contain uranium contamination. Curious about how exactly this works, I found a review article titled “Uranium Reduction” in the Annual Review of Microbiology written by Judy D. Wall and Lee R. Krumholz (Vol. 60: 149-166, Oct 2006). Following is a summary of what I found. Uranium is a metal with the symbol U on the periodic table. It has the atomic number 92 which means that it has 92 protons and electrons. In nature, occurs in three different forms U-238 (~ 99.238 %), U-235 (0.711 %), and U-234 (0.0058%) where each number refers to the combined num...

I can’t believe how fast time passes. I have been meaning on writing this post up for a long time now. In the last post, I just was introducing Shewanella onedeinensis and its ability to transfer electrons from a variety of organic substrates to metal oxides. Today, we shall look at one possible application for such a microbe: using bacteria to make electricity. This is done through contraptions called Microbial Fuel Cells (MFCs) but to understand MFCs we need to first understand how fuel cells work. There is going to be some detail. But the take-home message here though is: We can use certain bacteria to make electricity out of waste. A fuel cell is a device that produces electricity as long as one provides an external source of fuel and a source that accepts electrons known as oxidants. This is different from normal batteries because batteries simply release the electrical energy stored within them. They get tossed once they are used up. In the case of rechargeable batteries, e...

Today I came across a really interesting review article with the title “Towards environmental systems biology of Shewanella” that was published in the Nature Reviews journal (August 2008) . I became interested in it because the organism has some very interesting properites. Furthermore, the review article shows how interdisciplinary fields such as biology, chemistry, bioinformatics, and engineering can work together to come up with new ideas. So in the next two posts, I will describe what these little organisms are and explore a few unique potential uses. What is Shewanella spp? Shewanella spp is a genus of many related microbes that lives in many aquatic and sedimentary ecosystems under aerobic as well as anaerobic conditions where it can use many carbon sources as its food. Although the microbes have been in culture collections since the middle of the 20th century, it was not until 1988 that work on a particular member Shewanella oneidensis MR-1 lead to the recognition for mi...

As many of you have heard, Google has been very supportive concerning green energy. They have invested in several projects such as Prius Plugin Hybrids , Solar Panels on all their buildings, thermal energy, high-altitude wind energy extraction technologies, an d Engineered Geothermal Systems, with more to come (e.g. ocean-generators). If you read this blog, you are probably interested in this field and Google probably offers one of the best opportunities to work closely with these green technologies. "We are looking for a world-class team to lead this effort. We need creative and motivated entrepreneurs and technologists with expertise in a broad range of areas." (Joblist - click here) Source: http://www.google.com/corporate/green/energy/