What's in your spit?

Well just think of this....there are 10 times as many bacteria cells as human cells in a single human being.....your saliva is no exception...it has bacteria!

Oops! Survival of the fittest among bacteria...competition kills the weakest one!

Genetically engineered bacterium kills plants instead of helping them!

As far as the intended goals were concerned -- eliminating rotting organic waste and producing ethanol -- the genetically engineered bacterium was a success. But when a doctoral student named Michael Holmes decided to add the post-processed waste to actual living soil, something happened that no one expected. The seeds that were planted in soil mixed with the engineered Klebsiella sprouted, but then every single one of them died.

What killed them? The genetically engineered Klebsiella turned out to be highly competitive with native soil micro-organisms. Plants are only able to take nitrogen and other nourishment from the soil with the help of fungi called mycorrhizae. These fungi live in the soil and help make nutrients available to plant roots. But when the genetically engineered Klebsiella was introduced into living soils, it greatly reduced the population of mycorrhizal fungi in the soil. And without healthy mycorrhizal fungi in soils, no plants can survive.

Via: findarticles.com/

How to import Scarlett Johansson's pathogens

Yes she is famous. Yes she is a gorgeous actress. Yes she is human....SHE IS! What does that mean? That means that like any other human being, she has a bacterial flora. Nope...Scarlett's skin and mucosal secretions are NOT free of pathogens. You need a list of some of pathogenic bacteria that inhabit the upper respiratory tract? Here it is:

• Streptococcus mutans
• Candida albicans
• Streptococcus pyogenes
• Haemophilus influenzae
• Staphylococcus aureus
• Neisseria meningitidis
• Streptococcus pneumoniae
  

Because she admitted that she is recovering from a cold, apparently acquired through interacting with "The Spirit" fellow actor Samuel Jackson, her mucus-filled tissue now auctionned on eBay could contain potential pathogens. Because I am curious, I wanted to know if it was possible at all to buy Johansson's tissue and have it shipped (Free of charge according to the website) here in Canada. I made a few phone calls here and there (mostly to Health Canada) without a real answer...I was constantly referred to the Communications Officer. Then someone sent me a link that offers a few answers - Human Pathogens Import Regulations.

According to this document NO RISK GROUP 2, 3 or 4 pathogens can be imported. Just for your information, a risk group 2 pathogen is:

"A pathogen that can cause human or animal disease but is unlikely to be a serious hazard, and, while capable of causing serious infection on exposure, for which
there are effective treatments and preventive measures available and the risk of spread of infection is limited."

Every Streptococcus and Staphylococcus belongs to this group.

According to the Human Pathogens Import Regulations document:

No person shall import a human pathogen that belongs to Risk Group 2, 3 or 4 unless

(a) the importation is in accordance with a subsisting importation permit issued to that person under paragraph 7(a);

(b) prior to shipment of the human pathogen, that person notifies the supplier that the outer shipping container in which the human pathogen is transported must display clearly, on the outside surface of the container, the importation permit number and the following statement immediately preceding that number:

“Human Pathogen — Importation Permit Number:/ Agent anthropopathogène — Numéro du permis d’importation :”; and

(c) prior to shipment of the human pathogen, that person provides a copy of the importation permit to the supplier and notifies the supplier that a copy of the importation permit must accompany each shipment.

It looks like it can be very difficult to import Scarlett's snotty tissue. I feel bad that I am the bearer of such bad news....after all it's almost Christmas and that tissue could have been on a loved one list.....Happy Holidays! :o)

Dressing up for disease....

I have been saying that for a long time to my students including nursing and medical students. This article was publised on the New York Times website

"In 2004, a study from the New York Hospital Medical Center of Queens compared the ties of 40 doctors and medical students with those of 10 security guards. It found that about half the ties worn by medical personnel were a reservoir for germs, compared with just 1 in 10 of the ties taken from the security guards. The doctors’ ties harbored several pathogens, including those that can lead to staph infections or pneumonia.

Another study at a Connecticut hospital sought to gauge the role that clothing plays in the spread of methicillin-resistant Staphylococcus aureus, or MRSA. The study found that if a worker entered a room where the patient had MRSA, the bacteria would end up on the worker’s clothes about 70 percent of the time, even if the person never actually touched the patient."

Bacteria as tools....

After you watch this....go to this amazing site:
WWW.TED.com

Deadly space bugs

It is known that microgravity (MG) affects the way cells react. For example, astronauts coming back to Earth after a long time spent under very low gravity show signs of bone resorption and muscle mass loss. Bacteria react to low gravity too. In a paper published in 2002, Dr. Cheryl Nickerson and her team (see reference and link to pdf file below) discovered that the expression of many genes is in fact affected by MG (Figure on right). As can be seen, some genes are expressedm or not under normal gravity (1xg) but this expression pattern can be almost completely reversed under MG (or LSMMG - Low Shear Modeled Micro Gravity). Because gene expression seems to be influenced by microgravity, the obvious experiment was now to determine if the virulence of bacteria is increased un der MG...in other words are microbes susceptible to become "superbugs" in space? The answer, sadly, seems to be YES! In another study, to be published in PNAS, Dickerson and fisrt author James Wilson show that some virulence genes are in fact turned on by microgravity. In a mere 12 days in september, during spaceflight STS-115, Salmonella tiphymurium became more virulent. According to the authors, the shape of bacteria did not change but they seem to form a biofilm which is more difficult to eliminate by the immune system. In fact, when these "spacebugs" were fed to mice, they show a 3-times increase in virulence. Space is definitively a weird place to be...even for bacteria! Astronauts beware...bring your Purell!

For audio of this story follow this link

References:

1) James W. Wilson, Rajee Ramamurthy, Steffen Porwollik, Michael McClelland, Timothy Hammond, Pat Allen, C. Mark Ott, Duane L. Pierson, and Cheryl A. Nickerson. Microarray analysis identifies Salmonella genes belonging to the low-shear modeled microgravity regulon PNAS 2002 99: 13807-13812

2) Wilson et al. Space flight alters bacterial gene expression and virulence and reveals a role for global regulator Hfq. PNAS doi/10/1073/pnas.0707155104.

Toxins and perfumes: the death of dissidents and spies

The ex-spy is dead. Alexander Litvinenko died like a spy, almost like in a movie. An obscure poison got the best of him...but how toxic are poisons? Paracelsus once said: "everything is poison, it depends on the dosage"...some toxins are very powerful some less. Lets list a few toxins and compare them...just to have an idea.

• Botulism toxin is an exotoxin produced by Clostridium botulinum. This toxin is the MOST toxic toxin known to man. Its lethal dose is known to be around 200 pg/kg (so a human could be killed by as little as 10 ng of this toxin)...used as Botox
  
• Tetanospasmin is another highly lethal bacterial toxin. It is produced by Clostridium tetani bacteria. Ten times less powerful than botulinum toxin, it would take a dosage of 100 ng to kill a human.
• Strychnine is a plant derived toxin (from Strychnos nux-vomica tree) and is considered very toxic although it would take around 50 mg to kill a human. A problem with this toxin, the taste can be detected at very low doses
• Ricin is a toxin extracted from castor beans (Ricinus communis). Its lethal dose is 0.2mg. This toxin was used to kill Georgi Markov in London in 1978. Markov was shot in the leg and the bullet was coated with ricin.
• Sarin is a very toxic substance also known as O-Isopropyl methylphosphonofluoridate. This poison was used in a japanese subway in Tokyo in 1995 by a religious sect; Aum. The lethal dosage for sarin is around 0.5 mg (humans).
• Cyanide is a well known poison. There are various forms of this toxin so the dosage varies. Was widely used in suicides by Nazi. As a comparison, Sarin is know to be around 500 times more toxic than cyanide derivatives
• Dioxin is also a well known toxin. It was found in agent orange used as a defoliant durins the Vietnam war. Recently Viktor Yushchenko was poisoned with dioxin. The lethal dose of dioxin is around 1 mg.
• Polonium killed the ex-spy Alexander Litvinenko. Although that, weight for weight, this radioactive element is more toxic than cyanide it will take micrograms to milligrams to kill a human.
  

Are we the ORFans of the universe?

In a recent posting, the Christian Post stated: "Intelligent Design Defended by Unsolved Genetic Puzzle". This article appeared online on Nov. 17, 2006 at 2:45 PM.

In a recent conference, Dr. Paul A. Nelson (Biola University) stated that "I want to remind you that you don't need a theory of design to know that is design". In an attempt to discredit Darwin's theory of evolution by common descent, Dr. Nelson focused on ORFans, genes that seem to have no ancestral descent. In a nutshell, ORF (Open Reading Frames) are segments of DNA that code for proteins. As these genes change in evolution, a track is left. Following these tracks, through the use of computers and bioinformatics, can lead to a common ancestor. ORFans are genes that have no known common ancestor....but also, on a more technical point of view, ORFans are annotated open reading frames with no homologs in CURRENT databases. This could change with more research.

Dr. Nelson argues that humans rationality can detect intelligence without further evidence. He gave the mycoplasma example, a very simple organism that has 33% of its genes as ORFans. If I understand well, this points to the fact that the more ORFans an organism has, the higher the evidence that it originated from intelligent design.

Let me point you in another direction. Bacteriophages are bacterial viruses. These tiny creatures have the ability to inject their DNA in bacterial cells. According to Rocha and Danchin (2002) bacteriophages could be responsible for introducing A+T rich sequences into bacterial genomes (ORFans are known to be A+T rich sequences). So far, bacteriophage diversity has been poorly characterized....therefore homologs are difficult to find!

Dr. Nelson, please acknowledge that having no KNOWN homologs does NOT point in the direction of Intelligent Desing. Lets be objective here!

References:

E.P.C. Rocha and A. Danchin. 2002. Base composition bias might result from competition for metabolic resources. Trends in Genetics, 18:291-294.