 |
|
Study gives clues about how deadly bacterium gains foothold
December 19, 2006How a potentially deadly bacterium that could be used as a bioterrorist tool eludes being killed by the human immune system is now better understood, University of Iowa researchers report in the December issue of the Journal of Leukocyte Biology.
This bacterium, Francisella tularensis, is found naturally in the Northern Hemisphere and can be contracted through certain insect bites, contact with infected rabbits or ingesting contaminated food, water or air.
Francisella tularensis rarely infects people. However, because the bacteria has the potential to be used as a bioterrorist tool there is increased interest in understanding how it functions, said Lee-Ann Allen, Ph.D., associate professor of internal medicine and microbiology at the UI Roy J. and Lucille A. Carver College of Medicine.
"The rate of tularemia or 'rabbit fever' infection has significantly declined since the 1940s. However, the bacteria would be very deadly as an aerosolized terrorist weapon - inhaling as few as 10 bacteria could be potentially deadly," said Allen, who also is a staff researcher with the Veterans Affairs Iowa City Health Care System.
"We wanted to better understand how Francisella tularensis can overcome the body's innate immune response and cause disease. In addition, learning more about this bacterium can help us learn more about the overall human immune response to bacteria," she said.
The team focused on how Francisella tularensis evades being killed by a form of white blood cells called neutrophils. Normally, neutrophils can be quickly activated in response to infection, making them the equivalent of "first responders" for the human immune system, Allen said.
"We knew that Francisella could live inside other white blood cells called macrophages and not be killed by them," Allen said. "But little research had been done on the bacteria's survival in neutrophils.
"Early data indicated that neutrophils did not kill Francisella well. With new techniques, many of them more sensitive than in years past, we were able to look at that scenario more closely," Allen added.
The team mixed bacteria with neutrophils taken from healthy volunteers and studied the results.
"We found the neutrophils could ingest the bacteria but were not able to kill them. The Francisella somehow inhibit the ability of the neutrophils to perform two defensive functions that otherwise would kill the bacteria," Allen said.
One of the defensive functions is dependent on oxygen, and the other is oxygen-independent. Ideally, the two functions will be activated and kill the bacteria while they are trapped in a particular compartment within the neutrophils.
"The bacteria prevent these two functions from working in part by blocking the assembly of certain enzymes. After a few hours, the bacteria can escape the compartment instead of being killed, which leaves it able to replicate and cause harm,\\\
University of Iowa
"The rate of tularemia or 'rabbit fever' infection has significantly declined since the 1940s. However, the bacteria would be very deadly as an aerosolized terrorist weapon - inhaling as few as 10 bacteria could be potentially deadly," said Allen, who also is a staff researcher with the Veterans Affairs Iowa City Health Care System.
"We wanted to better understand how Francisella tularensis can overcome the body's innate immune response and cause disease. In addition, learning more about this bacterium can help us learn more about the overall human immune response to bacteria," she said.
The team focused on how Francisella tularensis evades being killed by a form of white blood cells called neutrophils. Normally, neutrophils can be quickly activated in response to infection, making them the equivalent of "first responders" for the human immune system, Allen said.
"We knew that Francisella could live inside other white blood cells called macrophages and not be killed by them," Allen said. "But little research had been done on the bacteria's survival in neutrophils.
"Early data indicated that neutrophils did not kill Francisella well. With new techniques, many of them more sensitive than in years past, we were able to look at that scenario more closely," Allen added.
The team mixed bacteria with neutrophils taken from healthy volunteers and studied the results.
"We found the neutrophils could ingest the bacteria but were not able to kill them. The Francisella somehow inhibit the ability of the neutrophils to perform two defensive functions that otherwise would kill the bacteria," Allen said.
One of the defensive functions is dependent on oxygen, and the other is oxygen-independent. Ideally, the two functions will be activated and kill the bacteria while they are trapped in a particular compartment within the neutrophils.
"The bacteria prevent these two functions from working in part by blocking the assembly of certain enzymes. After a few hours, the bacteria can escape the compartment instead of being killed, which leaves it able to replicate and cause harm,\\\
University of Iowa
Bacterium Current Events and Bacterium News RSSInsect Resistance to Bt Crops can be Predicted, Monitored, and Managed
Since 1996, crop plants genetically modified to produce bacterial proteins that are toxic to certain insects, yet safe for people, have been planted on more than 200 million hectares worldwide.
Factors from common human bacteria may trigger multiple sclerosis
Current research suggests that a common oral bacterium may exacerbate autoimmune disease. The related report by Nichols et al, "Unique Lipids from a Common Human Bacterium Represent a New Class of TLR2 Ligands Capable of Enhancing Autoimmunity," appears in the December 2009 issue of The American Journal of Pathology.
Delft breakthrough in bioethanol production from agricultural waste
With the introduction of a single bacterial gene into yeast, researchers from Delft University of Technology in the Netherlands achieved three improvements in bioethanol production from agricultural waste material: 'More ethanol, less acetate and elimination of the major by-product glycerol' This week the invention was published in the scientific journal Applied and Environmental Microbiology.
Biologists discover bacterial defense mechanism against aggressive oxygen
Bacteria possess an ingenious mechanism for preventing oxygen from harming the building blocks of the cell.
On the Trail of a Vaccine for Lyme Disease: Yale Researchers Target Tick Saliva
A protein found in the saliva of ticks helps protect mice from developing Lyme disease, Yale researchers have discovered. The findings, published in the November 19 issue of Cell Host & Microbe, may spur development of a new vaccine against infection from Lyme disease, which is spread through tick bites.
Sweet as can be: how E. coli gets ahead
Scientists at the University of York have discovered how certain bacteria such as Escherichia coli have evolved to capture rare sugars from their environment giving them an evolutionary advantage in naturally competitive environments like the human gut.
Iowa State University researcher discovers key to vital DNA, protein interaction
A researcher at Iowa State University has discovered how a group of proteins from plant pathogenic bacteria interact with DNA in the plant cell, opening up the possibility for what the scientist calls a "cascade of advances."
New insight into predicting cholera epidemics in the Bengal Delta
Cholera, an acute diarrheal disease caused by the bacterium Vibrio cholerae, has reemerged as a global killer. Outbreaks typically occur once a year in Africa and Latin America. But in Bangladesh the epidemics occur twice a year - in the spring and again in the fall.
Iron controls patterns of nitrogen fixation in the Atlantic
Scientists including researchers from the National Oceanography Centre, Southampton and the University of Essex have discovered that interactions between iron supply, transported through the atmosphere from deserts, and large-scale oceanic circulation control the availability of a crucial nutrient, nitrogen, in the Atlantic.
There's a speed limit to the pace of evolution, Penn biologists say
Researchers at the University of Pennsylvania have developed a theoretical model that informs the understanding of evolution and determines how quickly an organism will evolve using a catalogue of "evolutionary speed limits."
More Bacterium Current Events and Bacterium News Articles
 |
Bacterium Starring: Alison Whitney, Benjamin Kanes, Miya Sagara, Shelly Dague, Chuck McMahon Directed By: Brett Piper Also With: Marc Cavello (Cinematographer) An isolated outpost in the wilderness becomes a battleground between humankind and morphing microscopic monster in this gross-out shocker from horror master Brett Piper. When a handful of friends stumble upon the abandoned building, they come face to face with a biological weapons experiment gone catastrophically wrong. As the flesh-hungry contagion spreads from person to person – rendering each host into a pile of infectious ooze – it begins to multiply and increase in size. A covert military force sent in to destroy the organism discovers the extent of the slithering mutation, but by then it’s too late for conventional tactics. |
 |
Rising Plague: The Global Threat from Deadly Bacteria and Our Dwindling Arsenal to Fight Them by Brad Spellberg (Author) Antibiotic-resistant microbes infect more than 2 million Americans and kill over 100,000 each year. They spread rapidly, even in such seemingly harmless places as high school locker rooms, where they infect young athletes. And throughout the world, many more people are dying from these infections. Astoundingly, at the same time that antibiotic resistant infections are skyrocketing in incidence creating a critical need for new antibiotics research and development of new antibiotics has ground to a screeching halt! In Rising Plague, Dr. Brad Spellberg an infectious diseases specialist and member of a national task force charged with attacking antibiotic resistant infections tells the story of this potentially grave public health crisis. The author shares true and very moving patient... |
 |
Disposable EARLOOP Face MASK, Filters Bacteria 3 Ply - (Box of 50) by EVERREADY FIRST AID Tie-on surgical face mask with high bacterial filtration efficiency (BFE), low breathing resistance, soft, odorless, non-irritating, comfortable superior fit, fiberglass free. |
 |
Ein-O Science BioSigns Bacteria by Tedco The hands on cell and microbiology models provide magnified and cross section details. The set includes Virus, Bacteria, Plant Cell, White Blood Cell, Red Blood Cell and Animal Cell. Ein-O's I Know Guides and storage box are included. Consider using these models with a display of your own making - featuring the intricacies of cell structure, comparing and contrasting differences, investigating functions & interactions, or describing the efforts of modern medicine... a neat Science Fair Project. Virus - This hands-on interactive model provides magnified and cross-sectioned detailing of a Virus. Animal Cell - This hands-on interactive model provides magnified and cross-sectioned detailing of an Animal Cell. White Blood Cell - This hands-on interactive model provides... |
 |
Essick Air #1970 Quart Bacteria Treatment by ESSICK AIR PRODUCTS QT, Humidifier Bacteria Treatment, Helps Fight Bacteria & Algae Build Up, Keeps Water Smelling Clean, EPA Registered, For Use In All Evaporative Console & Room Size Humidifiers. |
 |
Enzymatic Therapy Acidophilus Pearls (90 Pearls) by Enzymatic This formula provides a combination of Acidophilus and Bididiobacterium species to support the overall health of the intestinal tract. |
 |
Watersafe WS-359RC Pool & Spa Bacteria Water Test 10-pack by Watersafe A do-it-yourself Pool and Spa bacteria test strips. Revolutionary way to test your pool and spa for harmful bacteria in just 20 minutes. Contains 10 tests. Now there is a simple test that detects bacteria in swimming pools and spas in less than 20 minutes, with a simple procedure that requires no instrumentation or user training. This Bacteria Test has all the accuracy and reliability of a lab test, but in a disposable test strip. How to use Pool and Spa Bacteria Test: * Open box * Sample water * Read results - immediate visual readout, no instruments required Detection Range: * Pseudomonas, Aeromonas, E.coli, species of Salmonella, Shigella, Enterobacter, Klebsiella and many other Coliform and non-Coliform bacteria. * 10^3 cfu/ml |
 |
Professioal Lab #BA110 Pro Bacteria/WTR Kit by PROFESSIONAL LAB INC Professional Bacteria & Water Test Kit, Easy To Use, Do It Yourself Test Identifies Dangerous Bacteria In 48 Hours, Offers 2 Types Of Analytical Methods, The First Method Simply Involves Counting The Number Of Colonies That Are Growing On The Petri Dish, The Second Method Optional Requires Sending The Petri Dish To Pro-Lab For A More Detailed Analysis Which Will Identify The Bacteria Present In Your Water, EPA Approved Lab Methods, Contains Petri Dish, Bacteria Medium, Calibrated Pipette/Dropper, Information Form. |
 |
Roller Coaster by Red Bacteria Vacuum |
 |
Hydrazona, A Terrifying Bacteria Starring: Mitsunobu Kaneko, Akio It?, Sh?zabur? Date, Yumiko Katayama, Tomomi Kuwabara Also With: Salvatore Billitteri (Producer) |
| © 2009 BrightSurf.com |