When Phages Attack: The War Against the Bacteria

Back in my high school days and my serious interests in micro-organisms, I pondered to myself, why don’t scientists modify bacteriophages to specifically target pathogenic bacteria. As it is, scientists today have increasingly researched this possibility as an alternative to conventional drug therapies. The use of bacteriophages to treat bacterial infection is called bacteriophage (or phage) therapy.

Bacteriophages have a high affinity towards specific receptor proteins bound on the surfaces of bacteria. This specificity allows the theoretical use of these viruses as treatment alternatives against pathogenic bacteria against human, animals, and even plants. The mechanism behind phage therapy is that the bacteria will lysis upon invasion of the bacteriophage, thus curing the disease. Because bacteriophages have a high specificity towards a specific type of bacteria, they would make excellent use since the phages would not damage other cells, unlike conventional drug therapies.

One of the issues dealing with conventional drug therapies is the penetration of biofilms. Drugs have a difficulty in being effective in the presence of a biofilm. Phage therapy doesn’t have this issue since the phages could bypass the biofilm and destroy the bacteria.

In drug therapies, bacteria can evolve to develop resistances against drugs, as in the case with MRSA. With phage therapy, the evolution of resistance to the phages theoretically should be balanced out with the evolution of the phage to continued infection of the bacteria. One study showed promising results in the use of phage therapy.

In Britain, H. W. Smith and M. B. Huggins (1982, 1983) carried out a series of studies on use of phages in systemic E. coli infections in mice and then in diarrheal disease in young calves. For example, they found that injecting 10⁶ colony-forming units of a particular pathogenic strain intramuscularly killed 10/10 of the mice, but none died if they simultaneously injected 10⁴ plaque-forming units of a phage selected against the K1 capsule antigen of that bacterial strain. This phage treatment was more effective than using such antibiotics as tetracycline, streptomycin, ampicillin or trimethoprim/sulfafurazole. Furthermore, the resistant bacteria that emerged had lost their capsule and were far less virulent.

Another possibility for phage therapy is to be used in conjunction with conventional drug therapies. Since some bacteriophages are lysogenic, these phages are able to combine their genetic material with the bacterial cell’s DNA. This insertion of genetic material may be able to code for proteins and enzymes that could weaken the bacteria’s defenses. After the weakening of the defense mechanism, conventional drug therapies would then destroy the bacteria as they normally would.

With the new research into phage therapy and the efforts put into modifications of genes, I leave you with this question. Would it not be possible to manufacture specific bacteriophages to target any bacteria in the near future?

Sources:

http://en.wikipedia.org/wiki/Phage_therapy

http://www.biotechjournal.com/Journal/feb2003/Article1text.htm

http://academic.evergreen.edu/projects/phage/phagetherapy/phagetherapy.htm

Microogranisms Saving the World

Microbiology appears in our daily lives everywhere, but the most valuable area that it is developing in is industrial biotechnology. Our mother-earth is in crisis; the amount of green house emissions is growing into an uncontrollable state and the amount of un-recyclable waste thrown away is nerve wracking. The human population consumes and consumes to a degree that in a very short time we will be left with no natural resources and a heavily polluted planet. The industrial biotechnology industry is working hard with combined efforts from nanotechnologists to find a cure to our petrochemical hungry lives.

Biotechnologists have devised a method to change foreign produced petroleum into domestically produced bio-fuels. This process began as a very clunky, slow and expensive procedure; however, it is now paving the way as a new inexpensive and environmentally friendly approach to power our vehicles. The idea for a new reusable transportation fuel was introduce with the notion that carbon from sugars in cellulose walls would be used instead of carbon from dinosaur fossils. A solution in using advanced enzymatic systems to break down the carbon skeletons from cellulosic biomass, such as crop residues, to sugars that feed yeast was introduced. The yeast produces ethanol as a metabolic product which in turn is the fuel that feeds cars. There are a couple of problems posed with this solution unfortunately. The first being, scientists needed to make it more economically viable by alternately using corn stovers or corn stocks (complex sugars) instead of corn (simple sugar) as a lower cost source. As well, technicians needed enzymes that would function in the high temperatures required for faster production of sugars. The first answer was brought with the discovery of Trichoderma reesei, a common soil fungus, that can manufacture a large amount of enzymes that break down cellulose. Like any plant enzyme, it had a natural tendency to denature, change shape, when exposed to extreme temperatures commanding it nonfunctional. So, scientists started to collect extremophiles, deep ocean micro-organisms called diatoms, which could function at these high temperatures. Diatoms build very elaborate silicon structures with intricate machinery to protect themselves in extreme environments. This posed a problem to scientists wanting to reproduce them by synthetic means. Nano-technicians stepped in and applied a new level of understanding to make reproduction feasible. Soon after, it didn’t take long for scientist to manipulate T. reesei to take the nature of diatoms. A new microbe was constructed that could withstand these high temperatures and cleave cellulose into individual sugars freeing them for ethanol production by yeast. Odd to think that one gallon of this cellulosic ethanol can replace three gallons of imported oil, which powers our motor vehicles, not at the sympathy of earth, but offered in safe emissions.

References:

http://www.bio.org/ind/

http://www.siu.edu/~ebl/leaflets/wang.htm

http://www.livescience.com/animals/050207_extremophiles.html

Image from:

http://www.livescience.com/animals/050207_extremophiles.html

How Far Down Does The Rabbit Hole Go?

There are a lot of vaccines present in the world today. But how many are really beneficial to us and, how many really provide what they advertise? Overall, the general public consensus on receiving a vaccination is favorable. Most of the time getting vaccinated is a good idea because it slows the development of viruses. But would you change your mind if you knew a little more about certain types of vaccines, Gardasil in particular?

First of all, lets address what Gardasil “really” prevents? This is a generic vaccination for four strains of viral oncogenes, Human Papilloma Virus (HPV), which causes cervical cancer. The vaccination covers only two of the major strains or causative oncogenes, 16 and 18. It also incorporates two minor strains of genital warts that could lead to HPV, 6 and 11. But there are over 100’s of known forms of HPV present that the vaccine does not cover. Scientists decided to vaccinate against these two prominent strains because they are the cause of 70% of cervical cancer. So where did the other 30% go? What happens if 16 and 18 evolve their glycoprotein receptors as a resistance to the new drug because it is under pressure? The vaccine is then rendered useless. Who knows how long this morphology will take because, the oncogenes have never been under this type of stress before. Then what? We discover another vaccine and another until we form a superbug. (Refer to Rochelle’s Blog posting, “Ear Infections Caused by Superbug”) Why bother if our bodies rid HPV naturally? Some women can contracted HPV and, cleared it without even knowing it because our bodies naturally clear it within two years with no symptoms. Which leads me to my next point, Gardasil will not prevent against previously contracted a strain of HPV. Have you ladies had a pap smear recently to know? Another downer to this vaccine is that there is also a 5-2% chance that Gardasil is not effective depending on the cancer that could develop; this is a very small chance but a chance none the less. My final point is that there is an indefinite time line as to how long the vaccine will be effective for. So who really knows when the vaccine will stop working? What is known, repeated inoculations over the course of 5 years for women within a small select age range from 9-26 are needed to make it effective. These are all facts that your doctor might already be able to tell you but, here is something that he/she might not know. All of these tests and stats have been conducted by Gardasil, the FDA has approved it. But the government or other authorities have not preformed their own separate testing yet. I do not doubt that Gradasil’s scientist know what they are doing but, my question is has the data been altered in some way? The only reason why I question this is because Merck, scientist that made Gardasil, produced an earlier product called Vioxx. Vioxx was supposed to reduce pain and help arthritis; however, it was taken off selves five years later because it was the cause of severe heart attacks and strokes. Merck hid the high risk of Vioxx from patients and doctors until the time of recall despite the warning from the US FDA about the marketing of Vioxx. So let me ask you this… Are you really covered?

I am sure everyone has seen the commercial that wants to make you believe that you are covered against cervical cancer. The commercial makes me think that they are more after our money than anything because it withholds very critical information about Gardasil. Gardasil even hands out free bags that contain some chocolate, fisherman’s friend, door hanger, condoms and coupon for Homesense but, there were no pamphlets that give any information about their product. Does Gardasil have something to hide this time?

What does all this have to do with Microbiology? HPV contains double stranded, circular DNA that codes for 12 genes. Two of these genes encode for proteins that make up the capsule (protein shell of virion), L1 and L2. Two code for the proteins E6 and E7 which disrupt the normal host cell cycle. The rest of the HPV genes mechanisms are unknown. In fact most of the HPV cycle is unknown because it is hard to grow viable colonies in lab. Although, studies have shown that the E6 and E7 protein translated by the host cell binds and degrade the tumor suppressor genes p53 and retinoblastoma. These tumor suppressor genes are responsible for maintaining the degree of growth and responding to growth ligands. Thus if these tumor suppressor genes are not functional it could result in the cell mutation and over growth of cells which could lead to cancer.

References:

http://www.fda.gov/cder/Offices/OODP/whatsnew/gardasil.htm

http://iafn.org/assembly/KMorgan%20Merck%20The%20Early%20and%20Long-Term%20Benefits%20of%20Preventing%20Low-Risk.pdf

http://www.bccdc.org/content.php?item=425

http://www.stanford.edu/group/virus/papova/HPV.html

http://www.adrworks.com/

Image from:

http://www.cartoonistgroup.com/store/add.php?iid=8829

Bovine Batteries,Cows as a source of electriciy?

Now I have heard everything! But I wasn't surprised to find that bacteria made this crazy concept possible. Naturally occurring bacteria in the cow's rumen, the first of the chambers in a cows stomach where microbial fermentation takes place,are to thank. These bacteria feed on cellulose which is converted into carbon dioxide, releasing electrons. A microbial fuel cell (MFC) generates electricity by acting as the electron acceptor in the bacterial metabolic process in an anaerobic environment.

Here is the basic principal of a MFC. There are two compartments that are separated by a thin membrane made of special material to allow the passage of protons. The bacteria (the rumen fluid) and substrate (the cellulose), are place in one compartment with a graphite rod. This is the anode. As the bacteria metabolises the cellulose the process releases electrons that move through the anode to the cathode compartment through a wire with a resistor. The movement of protons together with the flow of electrons across the wire creates an electrical current.

It takes two of the newest cells to produce enough electricity to recharge a AA battery. That doesn't seem like much now, but considering that cellulose is the most abundant resource on the planet this technology has promising possibilities for clean energy. And cellulose is just one type of organic matter that bacteria can convert to electricity, take for instance human waste.

Researches at Pennsylvania State University have build a microbial fuel cells that runs off of human waste water. Waste water is passed through a plastic tube that contains a graphite rod that acts as the anode and a home for the bacteria. As the bacteria feed on the waste they produce electrons that travel up the anode through wire to a cathode, producing an electrical current. The only thing is you have to keep the bacteria fed. Considering the food source, that shouldn't be a problem! This amazing device uses bacteria to treat waste water while producing energy. Could you image a sewage treatment plant that powered itself, a plant that cleans our water and powers our homes!

Refrences:

http://news.nationalgeographic.com/news/2004/03/0301_040302_sewagepower.html

http://www.sciencedaily.com/releases/2007/08/070821143612.htm

http://news.nationalgeographic.com/news/2005/09/0909_050909_cowbattery_2.html

http://www.microbialfuelcell.org/

New Laser Technology

Ultra-violet light is able to destroy micro organisms because of its low wave-length (10-400 nm) and high energy. The UV radiation is extremely harmful to cells because it causes thymine dimers to form in the DNA. The DNA replication mechanisms are unable to repair the dimers, this causes DNA replication to halt and then the cell enters apoptosis.

Traditional laser treatments are unable to discriminate between foreign cells and human cells. When this treatments are used not only destroy the virus or bacteria but human cells as well. The side effects of this kind of treatment include skin aging, damage to the DNA of human cells, and may also cause skin cancer. Another problem with this type of treatment is that it is not 100% effective.

There has been a recent discovery from the Arizona State University in which a laser that emits infrared pulses is able to discriminate between human and problem microorganism cells. This technology uses Femtosecond laser pulses, and through a process called Impulsive Stimulated Raman Scattering (ISRS), produces lethal vibrations in the protein coat of microorganisms, thereby destroying them. This laser is similar to the principles that work when high pitched noises shatter glass.

With this new technology the Femtosecond laser pulses use a process called impulsive Stimulated Raman Scattering which produced vibration in the protein coat of micro-organisms which destroys the viruses and bacteria without causing any damage to human cells. Only the bacterial or viral cells are destroyed because the protein coat of their cells are very different from the protein coat of human cells. However when selecting the wavelength and pulses of the laser you need to be careful to select one that will only damage/destroy the viral or bacterial cells and not the human cells as well. Otherwise you will still have similar problems that were caused by the UV laser radiation.

This new technology has many different applications. It can be used in hospitals to disinfect blood supplies as well as other bio materials. This would be very beneficial in a hospital setting because it would make sure that bio materials would be fully sterilized without have to worry about destroying the beneficial cells. Another hospital application would be to use it on infections such as MRSA. This technology can also be used for the treatment of blood-borne illnesses such as AIDS and hepatitis.

References:
http://www.sciencedaily.com/releases/2007/11/071101084950.htm
http://www.plasmetic.com/skin/lasers/new-laser-technique-kills-viruses-without-touching-human-cells.html
Prescott, Harley, & Klein's Microbiology Seventh Edition (Pg 142)

Ear Infections, what you should know...

A new super bug had been discovered in kids, ear infections that resist all antibiotics allowed for children. As we have feared for sometime now bacteria are evolving and becoming more and more resistant to antibiotics.

This newly found resistant bug is Streptococcus pneumoniae, it causes sever ear infections in children and infants. The only antibiotics that have been found to treat the bacteria cause sever joint problems in the kids who have taken them. Other treatments available for children include surgery and extremely aggressive therapy.

The Streptococcus Pneumonia if left untreated can cause much more serious problems such as pneumonia, blood stream infections, and meningitis.

“We need to alert doctors across North America that the possibility exists for a super bug,” says Dr. Michael Pichicher, a Microbiology and Immunology professor at the University of Rochester.

Sadly the bug has already caused serious problems. One child has lost all hearing due to the infection; the bug was not caught early enough and should have been treated sooner. Now that we are aware of the new pathogen we need to learn to recognize and test for the mutated infection earlier. We also need to work on developing a new antibiotic safe for the use of children to kill the ear infection.

Source: Canwest News Services
Alberni Valley Times (Wed Oct 17/07)
static.howstuffworks.com/

HPV and cervical cancer.

HPV, or human papillomavirus has been making the news and been a hot topic of controversy lately. Cervical cancer is the second most common cancer among women world wide and HPV infections are present in 100% of all cervical cancer patients, coincidence? Definitely not!

HPV is the most commonly transmitted infection in the United States and over half of all sexually active American are infected at some time in their lives. There are usually no symptoms so passing it to someone else without even knowing it is fairly easy, it requires only skin on skin contact to be transmitted. I am going to assume that the stats are pretty close for Canadians as well. Not so scary considering that most HPV infections will come and go without ever causing any symptoms, our ever amazing immune systems taking care of the virus before it causes any damage. But (of course there is a but), of the 37 types of HPV that are spread through sexual contact, there are about 19 "high risk"types that can develop into cervical cancer.
(ThinPrep Pap smear with group of normal cervical cells on left and HPV-infected cells on right. The HPV-infected cells show features typical of koilocytes: enlarged (x2 or x3) nuclei and hyperchromasia)

The virus does so by producing the proteins E6 and E7 which effectively inactivates or turns off the P53 gene. Why does this matter so much? The P53 gene is a tumor suppressor gene, a transcription factor that regulate the cycle and cell apoptosis. Without it there is excessive cell division that leads to tumors and cancer.

But alas, unlike other forms of cancer there is a vaccine. Gardasil and Cervarix are two types of vaccines that work against type 16 and 18 of the virus by getting the body to produce virus-neutralizing antibodies that will prevent initial infections. That's right, just like the flu shot! Hallow virus-like particles are produces from recombinant HVP coat proteins. What? Well, DNA from the viral protein coat are inserted into another organisms genome, such as the plasmids of bacteria. This DNA is expressed and a virus-like particle is assembled that has no viral DNA and therefore cannot cause infection. This initial vaccines is expected to last for 4.5 years with repeated inoculations later.

So we have a preventative measure, but what if you already have cervical cancer or cannot get the vaccines? Like any other form of cancer early detection is the key. Regular Pap smears and visits to your doctor are a must. Edward Yeung an Iowa State University professor has developed a method of detecting a single HPV molecule. The current test being used requires 10 to 50 viral molecules. This new technology, which is not in use yet, creates chemical reagents that recognize the genetic sequence of HPV. The reagents label the genome by florescence, which are lite when passed through a laser. "Yeung said single molecule detection of the virus could help women and families decide to get vaccinated. He said vaccines administered after such early detection could still have time to stop the virus."

Preventative measures and early detection, is cervical cancer going the way of Polio and the dinosaurs? Hopefully with education and common sense we can see a decline in the women who suffer from what now seem to be a preventable disease.

Refrences:

http://www.fhcrc.org/about/pubs/center_news/2005/nov17/sart5.html

www.thetech.org/genetics/news.php?id=32

http://en.wikipedia.org/wiki/P53

http://en.wikipedia.org/wiki/HPV=vaccine

http://www.sciencedaily.com/releases/2007/10/071030164855.htm

Image from

http://en.wikipedia.org/wiki/Images:ThinPrep_Pap_smear=HPV.jpeg