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(Bio) (Health) Bacteria: Cholera

 
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PostPosted: Thu Dec 08, 2005 1:57 pm    Post subject: (Bio) (Health) Bacteria: Cholera Reply with quote






Study may lead to cholera treatments

HANOVER, N.H., Dec. 7 (UPI) -- Dartmouth scientists say the bacterium causing cholera, Vibrio cholerae, uses the same protein to colonize the human intestine as it does surviving in water.

Researcher Ronald Taylor and colleagues have demonstrated the microbe uses the GbpA protein to do both.

The researchers say they believe it's only the second example demonstrating the molecular basis that enables a microbe to cause human disease, as well as survive in a natural environment.

According to the new study, GbpA appears to help the bacterium attach both to the surfaces of gut cells and to chitin, which forms the exoskeleton of zooplankton in aquatic ecosystems.

Taylor said the identification of GbpA's role should help medical experts develop new drugs to fight cholera.

************************************************************

Questions to explore further this topic:

What is cholera?

http://www.cdc.gov/ncidod/dbmd.....lera_g.htm
http://www.emedicine.com/ped/topic382.htm

What is dehydration, what is diarrhea?

http://www.caringforkids.cps.c.....ration.htm

What are bacteria?

http://www.microbe.org/microbes/bacterium1.asp

Why is hand washing important?

http://www.microbe.org/washup/Wash_Up.asp

Are all bacteria bad?

http://www.microbe.org/microbes/friend_or_foe.asp

How big is a cell, bacterium, etc.?

http://www.cellsalive.com/howbig.htm

Can we see bacteria?

http://ebiomedia.com/gall/bacteria/index.html#

Are there other illnesses one could get from the food and water they take?

http://www.agr.state.nc.us/cyb.....Badbug.htm

How does one avoid these bad bugs?

http://www.agr.state.nc.us/cyb.....ffacts.htm

Things to know about the water that we drink:

http://www.engr.uga.edu/servic.....9-10c.html

GAMES

http://www.fooddetectives.org/


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PostPosted: Tue Dec 27, 2005 7:48 am    Post subject: Pathogen Studies Could Result in Safer Produce Reply with quote

Pathogen Studies Could Result in Safer Produce
By Jim Core
December 12, 2005
Because conventional washing methods to remove microbial contaminants from fresh fruit and vegetable produce surfaces have been found to be only marginally effective, Agricultural Research Service (ARS) scientists in Wyndmoor, Pa., want to give the produce packing and processing industries better techniques.

Bassam A. Annous, a microbiologist at the ARS Eastern Regional Research Center, Food Safety Intervention Technologies Research Unit, in Wyndmoor, and his colleagues are developing new technologies to remove or inactivate pathogens on both fresh and minimally processed produce.

Bacteria can quickly attach to the produce surfaces and form what are called biofilms that likely improve their ability to colonize and survive. A biofilm is a mass of microbes attached to a surface and to each other by bacterial polymers (complex sugars). This polymer coating may protect bacterial cells from exposure to antimicrobial compounds, such as chlorine, used to sanitize produce.

The human pathogen Salmonella is often responsible for produce-related outbreaks of foodborne illness. For example, Salmonella is difficult to remove from cantaloupe surfaces, because it attaches to inaccessible sites and forms biofilm on the cantaloupe rind surface. This allows the pathogen to avoid contact with the sanitizing solution. Surviving Salmonella cells can then be transferred from the surface of the melon into the internal tissues during cutting prior to consumption.

Annous and his colleagues recently gained new insight into biofilm formation by Salmonella on various surfaces. The ability of Salmonella cells to form biofilm on plastic or stainless steel surfaces was dependent on the production of fimbriae (hairlike structures) and cellulose that help the cells attach to and colonize surfaces.

Biofilm formation by Salmonella cells starts by attaching to the rind of cantaloupe following contamination. Once attached to the rind, Salmonella cells rapidly develop biofilm by growing and excreting polymers. This new knowledge helps explain how Salmonella survives harsh sanitizing environments.

Read more about the research in the December 2005 issue of Agricultural Research magazine.

ARS is the U.S. Department of Agriculture’s chief scientific research agency.
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PostPosted: Wed Dec 28, 2005 11:57 am    Post subject: Some Fruits & Veggies Might Make Your Sick Reply with quote

Some Fruits & Veggies Might Make Your Sick

ABC-HEALTH NEWS - We're getting the message that we've been hearing since childhood: fruits and vegetables are good for you! Americans eat more pounds of produce than ever before. But while fresh foods are a critical part of a good diet, some of them could cause some decidedly unhealthy reactions.

A few months ago, Mike Stein ate something he thought might have made him sick.
He got violently ill and figured it was it from the scallops he ate, but when he called the health department he was very surprised to find what actually caused the reaction. He said that the health department suspected it was some sort of vegetable or fruit contamination.

He was even more surprised when they told him it wasn't unusual.


In fact, according to the CDC, contaminated fruits and veggies cause more food borne illness than even meat, poultry or eggs and the problem's growing.

CDC doctor Patricia Griffin says, "When we look at all of our outbreaks, about 13 percent of those people got ill from eating a fresh fruit or vegetable, one that was consumed raw, and that's double what we saw 10, 15 years ago."

One reason for this is pre-cut produce. She says that once a fruit or vegetable has been cut, it can be a better medium for growth of bacteria.

Also, veggies now come from more places and the process is tough to track.

"For example, lettuce is harvested. It will get washed, but maybe it will be in wash water that's contaminated," says Griffin.

The biggest culprits, according to the government, are lettuce, melons, sprouts, tomatoes and green onions.

Of course, fruits and vegetables are critical parts of a balanced diet. No one suggests you avoid them, but you can follow this tip from the CDC: wash your fresh fruits and vegetables before you eat them; peel your fruits and cut out any parts that are bad.

And one more thing to keep in mind - if you do peel and cut your fruit or veggies, make sure to refrigerate them right away to slow down bacteria growth.


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PostPosted: Wed Dec 28, 2005 1:35 pm    Post subject: What you don’t know can harm you Reply with quote

What you don’t know can harm you
STAR SCIENCE By Mary Anne Q. Astilla
The Philippine STAR 12/29/2005

"Anything that can be eaten will be eaten" was the first statement Dr. Ed Padlan said during our seminar class at the UP Marine Science Institute. Our topic wasn’t about predators and prey in the vast ocean but something more familiar to us – the human body. It wasn’t a seminar course in Marine Ecology after all, but in Molecular Immunology.

It is quite amusing how we can go on with our daily tasks and not notice and feel the "battle" going on inside us. In connection with the first statement I quoted from my professor, it is unfortunate that we are, in a way, food – a source of nutrition and essential for the survival of a wide array of microorganisms. But fortunately enough, our body has defense mechanisms to overcome this attack by preventing the entry or containing the spread of these foreign materials collectively called antigens, once they are able to find their way inside our cells or in the body in general. The immune system, composed of humoral and cellular components, is responsible for our survival despite the ubiquitous presence of bacteria and other pathogens (disease-causing agents). This brings to mind an experiment in our Microbiology class back in college wherein we prepared sterilized agar culture media in petri dishes. We exposed one to the open air, others were made to come in contact with the doorknob, to a money bill, and lastly, with our own hands. It was a total revelation of the presence of bacteria everywhere when several different bacterial colonies were seen in all plates after incubation. It is unimaginable how many of those kinds we will have to come in contact with during our lifetime. It’s a relief to learn what our immune system can do. The humoral arm of the immune system involves antibodies that circulate in the body fluids and specifically recognize antigens such as bacterial and viral components. There are approximately 108 different B cells in one’s body each producing antibodies with different specificities at any given time. Antibodies cross-link with the antigens and form an immune complex that is engulfed by macrophages (a cellular component). Aside from the macrophages, the cellular arm is composed of cytotoxic T lymphocytes (CTLs), and T-helper cells. CTLs target and kill cells expressing fragments of the antigen on its surface. T helper cells direct antibody- and cell-mediated immune responses through the secretion of molecules called cytokines that have important effects on B cells, CTLs and other immune cells. However, despite the sophistication and complexity of our immune system, having been a product of evolution for quite a long time, our body may still lose control and succumb to invaders. Most, if not all, pathogens are continuously evolving by the process of mutation to be able to crack down the defenses of their host, develop a new mode of transmission, and expand their host choices.

Let’s take, for example, the Human Immunodeficiency Virus or HIV, the retrovirus that causes AIDS. The retrovirus’ genetic material is in the form of RNA instead of the usual DNA but it possesses an enzyme called reverse transcriptase that converts RNA to DNA. This allows the retrovirus to use the genetic machinery of the host cell for its own replication. Our immune system initially has the ability to contain HIV infection, as it is able to produce antibodies directed to the HIV. But after some time, the immune system is subverted and the person becomes susceptible to diseases caused by other pathogens, which normally would have been easily regulated by the immune system. The latter signals the onset of AIDS. The progression from HIV infection to AIDS tends to vary between individuals and the HIV strain. How is HIV able to get away from the offense launched against it? It is tempting to believe that there is such a thing as "viral intelligence" as Dr. Padlan would usually refer to it. It is interesting to note that this highly evolved virus seems to be using a very ancient tactic – a successful approach used in the Trojan war of ancient Greece – the Trojan Horse. Integrating the existing data on retroviral biology, researchers from the John Hopkins University composed of Dr. Stephen Gould, Amy Booth and James Hildreth came up with a model of retroviral biogenesis and transmission and called it the Trojan Exosome Hypothesis. An article bearing the same title was published in the Sept. 16, 2003 issue of the Proceedings of the National Academy of Sciences (PNAS).

Exosomes are small membrane bound molecules that are released into the external environment, which fuse with membranes of neighboring cells to deliver membrane and cytoplasmic proteins from one cell to another. Inter-cellular signaling by exosome exchange is important in many physiological processes, including lymphocyte activation and the development of immunological tolerance

Previous models of retroviral transmission assumed that the binding and fusion of retroviruses, such as HIV, to host cells are completely dependent on the retroviral envelope proteins. This is not the case, however, as retroviruses can have many types of host cell molecules and are capable of receptor- and envelope-independent infections. The Trojan Hypothesis states that the retrovirus taps the pre-existing, non-viral pathway of exosome biogenesis and exosome uptake for the formation of retroviral particles and transmission, respectively. As the cells involved in the process of immune surveillance and signaling circulate throughout the body, they are exposed to numerous exosomes, which may be loaded with retroviral particles. As it replicates predominantly in the immune cell population, it is able to evade attack launched by the immune system and at the same time disrupt the host’s response to the infection, thereby enabling continuous replenishment of the virus population.

Despite the tremendous efforts in HIV and human immune system research, an ideal vaccine has not yet been made. This difficulty lies in the HIV’s extraordinarily high mutation rate. This also allows the virus to evolve resistance to the drugs used for treatment. And this is further aggravated by the fact that HIV exploits the immune system designed to stop it and other infections. It is by increasing our knowledge of how the HIV and the components of our immune system interact at the molecular level that an effective approach to combat HIV infection and AIDS may be developed. As Sun Tzu stated in his book The Art of War, "If you know the enemy and you know yourself you need not fear the results of a hundred battles." * * *
Mary Anne Q. Astilla completed her BS Marine Biology degree at the University of San Carlos, Cebu City. She is currently an M.S. Marine Science student majoring in Marine Biotechnology at the University of the Philippines-Marine Science Institute. E-mail her at m_astilla@yahoo.com
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PostPosted: Sat Mar 04, 2006 12:36 pm    Post subject: New Method for Identifying Microbes Reply with quote

New Method for Identifying Microbes
Brookhaven National Laboratory
Genomic “tags” quickly catalog species, distinguish pathogens from harmless relatives
March 3, 2006

UPTON, NY -- Scientists at the U.S. Department of Energy’s Brookhaven National Laboratory have developed a new, high-throughput technique for identifying the many species of microorganisms living in an unknown “microbial community.” The method, described in the March 2006 issue of Applied Environmental Microbiology, has many applications — from assessing the microbes present in environmental samples and identifying species useful for cleaning up contamination to identifying pathogens and distinguishing harmless bacteria from potential bioterror weapons.

“Microbial communities are enormously diverse and complex, with hundreds of species per milliliter of water or thousands per gram of soil,” said Brookhaven biologist Daniel (Niels) van der Lelie, lead author of the study. “Elucidating this complexity is essential if we want to fully understand the roles microbes play in global cycles, make use of their enormous metabolic capabilities, or easily identify potential threats to human health.”

Growing cultures of microbes to identify species is slow and error prone as the culture conditions often screen out important members of the community. Sequencing entire genomes, while highly specific and informative, would be too labor intensive and costly. So scientists have been searching for ways to identify key segments of genetic code that are short enough to be sequenced rapidly and can readily distinguish among species.

The Brookhaven team has developed just such a technique, which they call “single point genome signature tagging.” Using enzymes that recognize specific sequences in the genetic code, they chop the microbial genomes into small segments that contain identifier genes common to all microbial species, plus enough unique genetic information to tell the microbes apart.

In one example, the scientists cut and splice pieces of DNA to produce “tags” that contain 16 “letters” of genetic code somewhat “upstream” from the beginning of the gene that codes for a piece of the ribosome — the highly conserved “single point” reference gene. By sequencing these tags and comparing the sequenced code with databases of known bacterial genomes, the Brookhaven team determined that this specific 16-letter region contains enough unique genetic information to successfully identify all community members down to the genus level, and most to the species level as well.

“Sequencing is expensive, so the shorter the section you can sequence and still get useful information, the better,” van der Lelie said. “In fact, because these tags are so short, we ‘glue’ 10 to 30 of them together to sequence all at one time, making this a highly efficient, cost-effective technique.”

For tag sequences that can’t be matched to an already sequenced bacterial genome (of which there are only a couple hundred), the scientists can use the tag as a primer to sequence the entire attached ribosomal gene. This gene is about 1400 genetic-code-letters long, so this is a more time-consuming and expensive task. But since ribosomal genes have been sequenced and cataloged from more than 100,000 bacterial species, this “ribotyping” technique makes use of a vast database for comparison.

“If there’s still no match,” said van der Lelie, “then the tag probably identifies a brand new species, which is also very interesting!”

In another test with possible applications for identifying agents used in bioterror attacks, the technique also clearly discriminated between closely related strains of Bacillus cereus, a pathogenic soil microbe, and Bacillus anthracis, the bacterial cause of anthrax.

This technique could also help assess how microbial community composition responds to changes in the environment. Such information might help identify which combinations of species would be best suited to, say, sequestering carbon or cleaning up radiological contamination.

This study represents just one application of genome signature tagging, a technique developed at and patented by Brookhaven Lab. Brookhaven scientists have also used genome “tags” to identify the sites where regulatory proteins bind to DNA (more) . This research could greatly speed the process of unraveling the role these proteins play in turning on and off certain genes in different types of cells — as well as what might go awry in conditions like cancer.

This research was funded by the Office of Biological and Environmental Research within the U.S. Department of Energy’s Office of Science and by Brookhaven’s Laboratory Directed Research and Development funds.
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PostPosted: Thu Mar 09, 2006 11:22 am    Post subject: Researchers' new approach to defeating Gram-negative bugs Reply with quote

March 8, 2006
University of Michigan

Researchers' new approach to defeating Gram-negative bugs

ANN ARBOR, Mich.—Ronald Woodard’s team set out looking for a way to kill a stubborn type of bacteria and they succeeded—but not in the way he expected.

"We didn’t get there the way we thought we’d get there, but in the end, we were right," said Woodard, chair of medicinal chemistry at the University of Michigan College of Pharmacy.

Woodard is senior author of an article describing way he and his research team genetically modified Escherichia coli bacteria, known as a Gram-negative bug, to weaken its defenses. That article appears in the recently released inaugural issue of the American Chemical Society’s journal ACS Chemical Biology.

Some of the better-known Gram negatives are salmonella, gonorrhea, cholera and meningicoccal meningitis, along with the bacteria that caused the black plague.

After their genetic modifications, E. coli was killed with just a fraction of the antibiotic dose typically needed. It was 512 times more susceptible to Rifampin, 256 times more vulnerable to Novobiocin, and eight times more susceptible to Bacitracin, suggesting doses could be dramatically cut and still be effective, Woodard said. Antibiotics typically only effective against Gram-positive bacteria could work against Gram-negative bacteria if a compound can be designed to mimic this genetic modification, Woodard said.

Also, E. coli can typically withstand the bile salts found in the human digestive tract, but by weakening it, Woodard’s team found E. coli would die in the presence of normal levels of bile salts to which the bacteria would be exposed in the human gut.

Besides differing in how they respond to Gram’s coloring test, Gram-positive and Gram-negative bacteria look different. Gram-positive cells are smooth on the outside, while Gram-negative cells have sugars and carbohydrates on the outside in structures that look like hairs.

That exterior protection is part of what makes Gram-negative bacteria harder to kill with antibiotics, Woodard said.

Woodard’s team set out to genetically modify the cells to eliminate the key sugar to which the hair anchors on the outside of the cell.

"Unfortunately, the bug didn’t die," Woodard said. The researchers found that a "backup" gene from a different pathway also could form the anchor, so they knocked out that gene, as well. Initially the cell with both genomic knockouts did not survive without special nutritional supplements. Later, they were surprised to see that with different growth conditions, the cell began to grow again but without the hair-like structure.

The cells survived—but they looked a lot like Gram-positive cells, without all the sugars on the outside.

"We, as well as the entire scientific community, always thought Gram-positive cells could not survive without this external structure. This shows that is not true," Woodard said. Though they didn’t die, they were weakened, and that made the cells an easy target for antibiotics.

Because Woodard suspected he might be flying in the face of conventional wisdom on bacteria, he solicited second opinions from the Borstel Research Center in Germany, which does a good deal of work on Gram-negative bacteria. Scientists there were initially skeptical, he said, but eventually, Uwe Mamat and Buko Lindner from Borstel signed on to the project and became co-authors of the current paper.

Other members of the team were U-M medicinal chemistry doctoral students Timothy Meredith and Parag Aggarwal. Meredith, lead author of the publication, has since joined Harvard Medical School as a researcher.

Aggarwal, Mamat and Woodard continue to work on the approach, encouraged by the potential of developing a safer way to treat patients. They hope their research leads to combination therapies, which include compounds that could duplicate the effect caused by the genetic mutation of bacteria together with low-dose antibiotics.

"Bugs are very smart," Woodard said. "It’s not a matter of if a bug will become antibiotic resistant, but when. We have to work hard to get ahead of them."

Woodard’s research is funded in part by a $2 million, five-year grant from the National Institutes of Health.
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PostPosted: Mon May 22, 2006 8:32 am    Post subject: Research highlights how bacteria produce energy Reply with quote

American Society for Microbiology
22 May 2006

Research highlights how bacteria produce energy

ORLANDO – May 22, 2006 -- The world's smallest life forms could be the answer to one of today's biggest problems: providing sustainable, renewable energy for the future. Using a variety of natural food sources, bacteria can be used to create electricity, produce alternative fuels like ethanol and even boost the output of existing oil wells, according to research being presented this week at the 106th General Meeting of the (ASM) American Society for Microbiology in Orlando, Florida.
"Microbial fuel cells show promise for conversion of organic wastes and renewable biomass to electricity, but further optimization is required for most applications," says Derek Lovley of the University of Massachusetts in Amherst. Earlier this month, Lovley announced at a meeting that he and his colleagues were able to achieve a 10-fold increase in electrical output by allowing the bacteria in microbial fuel cells to grow on biofilms on the electrodes of a fuel cell.

This week, Gemma Reguera, a researcher in Lovley's lab will present data identifying for the first time how these bacteria are able to transfer electrons through the biofilms to the electrodes.

"Cells at a distance from the anode remained viable with no decrease in the efficiency of current production as the thickness of the biofilm increased. These results are surprising because Geobacter bacteria do not produce soluble molecules or 'shuttles' that could diffuse through the biofilm and transfer electrons from cells onto the anode," says Reguera.

She and her colleagues discovered that the bacteria produce conductive protein filaments, or pili 'nanowires,' to transfer electrons. The finding that pili can extend the distance over which electrons can be transferred suggests additional avenues for genetically engineering the bacteria to further enhance power production.

Researchers from the Universidad Nacional Autonoma de Mexico announce that they have genetically engineered the bacterium Bacillus subtilis to directly ferment glucose sugar to ethanol with a high (86%) yield. This is the first step in a quest to develop bacteria that can breakdown and ferment cellulose biomass directly to ethanol.

"Currently ethanol is produced primarily from sugarcane or cornstarch, but much more biomass in the whole plant, including stems and leaves, can be converted to ethanol using clean technology," says Aida-Romero Garcia, one of the researchers on the study. The next step is to engineer the bacteria to produce the enzymes, known as cellulases, to break the stems and leaves down into the simple carbohydrates for fermentation.

Bacteria can not only produce alternative fuels, but could also aid in oil production by boosting output of existing wells. Michael McInerney and his colleagues at the University of Oklahoma will present research demonstrating the technical feasibility of using detergent-producing microorganisms to recover entrapped oil from oil reservoirs.

"Our approach is to use microorganisms that make detergent-like molecules (biosurfactants) to clean oil off of rock surfaces and mobilize oil stuck in small cavities. However, up till now, it is not clear whether microorganisms injected into an oil reservoir will be active and whether they will make enough biosurfactant to mobilize entrapped oil," says McInerney.

He and his colleagues were able to inoculate an oil reservoir with specific strains of bacteria and have these bacteria make biosurfactants in amounts needed for substantial oil recovery.

"We now know that the microorganisms will work as intended in the oil reservoir. The next important question is whether our approach will recover entrapped oil economically. We saw an increase in oil production after our test, but we need to measure oil production more precisely to be certain," says McInerney.
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PostPosted: Fri Jun 02, 2006 12:08 pm    Post subject: We are not entirely human, germ gene experts argue Reply with quote

We are not entirely human, germ gene experts argue
By Maggie Fox, Health and Science Correspondent
Reuters
Thu Jun 1, 2:13 PM ET



We may not be entirely human, gene experts said on Thursday after studying the DNA of hundreds of different kinds of bacteria in the human gut.

Bacteria are so important to key functions such as digestion and the immune system that we may be truly symbiotic organisms -- relying on one another for life itself, the scientists write in Friday's issue of the journal Science.

Their findings suggest that studying bacteria native to our bodies may provide important clues to disease, nutrition, obesity and how well drugs will work in individuals, said the team at The Institute for Genomic Research, commonly known as TIGR, in Maryland.

"We are somehow like an amalgam, a mix of bacteria and human cells. There are some estimates that say 90 percent of the cells on our body are actually bacteria," Steven Gill, a molecular biologist formerly at TIGR and now at the State University of New York in Buffalo, said in a telephone interview.

"We're entirely dependent on this microbial population for our well-being. A shift within this population, often leading to the absence or presence of beneficial microbes, can trigger defects in metabolism and development of diseases such as inflammatory bowel disease."

Scientists have long known that at least 50 percent of human feces, and often more, is made up of bacteria from the gut. Bacteria start to colonize the intestines and colon shortly after birth, and adults carry up to 100 trillion microbes, representing more than 1,000 different species.

They are not just freeloading. They help humans to digest much of what we eat, including some vitamins, sugars, and fiber. They also synthesize vitamins that people cannot.

"Humans have evolved for million of years with these bacteria. And they provide essential functions," Gill said.

GERM SURPRISE

Gill and his team sequenced the DNA in feces donated by three adults. They found a surprising amount of it came from bacteria.

They compared the gene sequences to those from known bacteria and to the human genome and found this so-called colon microbiome -- the entire sum of genetic material from microbes in the lower gut -- includes more than 60,000 genes.

That is twice as many as found in the human genome.

"Of all the DNA sequences in that material, only 1 to 5 percent of it was not bacterial," Gill said.

"We were surprised."

They also found a surprising number of Archaea, also known as archaebacteria, which are genetically distinct from bacteria but which are also one-celled organisms often found in extreme environments such as hot springs.

The donors were healthy adults. None had taken antibiotics for a year, as these drugs are known to disturb the bacteria in the body.

Gill said his team hopes now to make a comparison of the gut bacteria from different people.

"The ideal study would be to compare 20 people, 30 people from different ethnic backgrounds, different diets, drinkers, smokers, and so on, because I think there are going to be distinct differences," Gill said.

These bacteria almost certainly help break down drugs that people take and studying the effects of different populations of the microbes might provide clues to treating different people with various medications.

The next study will focus on the bacteria in the mouth, Gill said. There are at least 800 species in the mouth and maybe more, Gill said.
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PostPosted: Mon Oct 02, 2006 1:34 pm    Post subject: Foodborne pathogens hard to remove from produce Reply with quote

University of Illinois at Urbana-Champaign
2 october 2006

Foodborne pathogens hard to remove from produce, research is ongoing

URBANA – Will you ever feel comfortable eating fresh spinach again? All raw agricultural products carry a minimal risk of contamination, said a University of Illinois scientist whose research focuses on keeping foodborne pathogens, including the strain of E. coli found recently on spinach, out of the food supply.

That won't keep Scott Martin, a U of I food science and human nutrition professor, from eating bagged greens or other produce although he can see why it gives consumers pause.

"I definitely wouldn't eat spinach from the three California counties implicated in this latest outbreak of E. coli H0157:H7, but there have been no problems with spinach grown in other parts of the country," Martin said.

Martin said that food companies have recalled the particular products implicated in the outbreak, and that the contaminated spinach had a sell-by date of September 20, so none should remain on the shelves at this time.

If his reassuring tone makes the scientist sound less than aggressive toward E. coli 0157:H7 and other foodborne pathogens, you're mistaken. Martin and fellow U of I professor Hao Feng are dedicated to discovering ways to keep these microorganisms out of the food supply.

Martin's research is focused on finding ways to eliminate the biofilms that attach to produce and cause illness. "Once the pathogenic organism gets on the product, no amount of washing will remove it. The microbes attach to the surface of produce in a sticky biofilm, and washing just isn't very effective," he said.

"Another problem with this pathogen is that it has a very low infective dose. It only takes between 10 and 100 cells to cause an infection, so it's impossible to achieve a safe level of the pathogen once it gets on the product. At this point, we need to concentrate on avoiding a crop's exposure to the pathogen as the produce is being grown," he said.

Martin said the California spinach outbreak appears to have been caused by contaminated cow manure used by organic producers. "A very low percentage of cattle are always infected by this strain of E. coli. If fresh manure from those cattle is used as fertilizer, there's an outbreak in the making."

Growers should also be careful about the water they use on the plants. "If farmers irrigate with water from a lake close to a dairy farm, that can also be a potential source of infection," Martin said.

Another technique that has excellent potential in the fight against E. coli 0157:H7 is being developed in the lab of Martin's colleague Hao Feng. Feng is developing a process that uses ultrasound and low temperatures to kill pathogenic organisms in liquid products, such as cider and apple juice. A previous outbreak of E. coli 0157:H7 occurred in these products, Martin said.

"Before that outbreak, small producers could sell cider or apple juice without pasteurizing it. Now all growers are required to pasteurize these products," he added.

The scientist said normal, wild-type strains of E. coli live in the human intestinal tract as a beneficial organism, aiding in digestion and absorption of nutrients.

"Only a few strains of E. coli are pathogenic, and E. coli 0157:H7 is a really virulent strain. In most cases, it causes bloody diarrhea and abdominal pain, and in a small percentage of victims, it colonizes the intestinal tract and produces a toxin that can cause kidney failure. It's certainly an unpleasant and potentially fatal illness," he said.

"But, if you consider the amount of produce that's grown in this country and the number of reported cases we see, your risk of contracting the illness is actually very small," he noted.

In the meantime, Martin continues to study the biofilms that pathogens use to adhere to produce, and Feng experiments with ultrasound treatments that are yielding encouraging results. The scientists believe their work will soon make the food supply safer.
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PostPosted: Tue Jan 23, 2007 7:44 am    Post subject: Study: Microwaves Kill Kitchen Germs Reply with quote

Study: Microwaves Kill Kitchen Germs

By LiveScience Staff

posted: 22 January 2007
04:50 pm ET

Sponges and kitchen scrub brushes can be loaded with disease-causing viruses and bacteria.

So microwave them, scientists say.

Researchers soaked sponges and scrubbers in a disgusting brew of raw wastewater containing fecal bacteria, viruses, protozoan parasites and bacterial spores, including Bacillus cereus spores—known for being very hard to kill with heat, chemicals and even radiation.

Zapping at full power for two minutes killed or inactivated 99 percent of living pathogens. It took 4 minutes to destroy the B. cereus spores.

For the full article:

http://www.livescience.com/hum.....owave.html

Important Note

The sponge must be wet, otherwise, it may burn inside the microwave
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PostPosted: Tue Jan 30, 2007 7:18 am    Post subject: Cholera pathogen reveals how bacteria generate energy to liv Reply with quote

Rensselaer Polytechnic Institute
29 January 2007

Cholera pathogen reveals how bacteria generate energy to live

Troy, N.Y. -- Researchers at Rensselaer Polytechnic Institute have discovered new details about how bacteria generate energy to live. In two recently published papers, the scientists add key specifics to the molecular mechanism behind the pathogen that causes cholera. The work could provide a better understanding of this pathogen, while also offering insight into how cells transform energy from the environment into the forms required to sustain life.

As a single-cell organism, Vibrio cholerae depends on resources in its immediate environment to sustain itself. Blanca Barquera, assistant professor of biology at Rensselaer and principal investigator for the project, studies an enzyme that resides in the membrane that encapsulates V. cholerae. This enzyme, known as NQR, pumps sodium ions out of the bacteria to generate a difference in concentrations between outside and inside. This gradient acts like a battery that powers essential cell functions, such as the movement of the bacterium’s tail, the flagellum.

Most cells, including human cells, use gradients of protons for this energy conservation function, but enzymes that work with sodium ions are ideal for experimental study, according to Barquera. Sodium is easier to trace and its concentration can be changed without affecting pH, which is a complication with protons. "It’s a very good system to understand this very basic mechanism charging this battery to create energy," she said.

In order to learn how the enzyme works, researchers are trying to get an idea of its three-dimensional structure. "The enzyme is like two machines together — imagine the turbine and generator of a hydroelectric dam. One is the source of energy; the other uses this energy to pump ions out of the cell," Barquera said. How the two machines are connected is one key question.

In the first paper, published in the Journal of Bacteriology, Barquera tackled the question of how the structure of the enzyme is organized with respect to the two sides of the membrane. The problem is that the enzyme is not amenable to standard methods of determining structure. Since an ion pump needs to carry ions from one side of the bacterial membrane to the other, the enzyme has to reach all the way from the water-like medium inside the cell, through the oily membrane interior, to the water-like environment outside the cell. For this reason, the enzyme is made up of water-soluble and oil-soluble components within a single entity, so it can’t hold its shape in any one solvent.

Using a stepwise process, Barquera attached labels at significant points along the length of the protein and then determined whether these labels appeared inside or outside the envelope of the cell membrane. The results showed that the cofactors — important parts of the enzyme’s machinery — are all located on the inner side of the membrane, which corresponds to the "intake" port of the ion pump.

The second paper was published in the Journal of Biological Chemistry. In this study, Barquera focused on structures, known as flavins, within the enzyme that carry the electric current that drives the ion pump. Using an interdisciplinary approach that combined genetic methods — to modify the enzyme structure — with an analytical technique known as Electron Paramagnetic Resonance Spectroscopy, which observes electron spin, she and her co-worker Mark Nilges at the University of Illinois analyzed the properties of the flavin molecules, and mapped these functional properties to specific points in the protein structure.

NQR is only one of several sodium pumping enzymes that Barquera plans to study. Because these enzymes are significantly different from human proteins that do similar work, some of them might be targeted by novel antibiotics. "An inhibitor or drug would be specific," she said. "You could kill the bacteria without doing anything to the human host."

But Barquera believes that the most important benefits of her research could develop in ways that cannot be foreseen: "From the basic science point of view, the more you know, the better," Barquera said. "It’s basic science that will take us to unexpected places."

One of those unexpected places in Barquera’s career has been her developing interest in the physiology and life cycle of V. cholerae itself. Much of what is known about V. cholerae is from study of the organism when it is in the body, yet the bacteria spend most of their lives outside their hosts. Study of the rest of the life cycle could be important in disease prevention.

"We have to know the enemy," Barquera said. As it stands, "We are trying to kill our enemies with very little knowledge."

###
This research was funded by grants from the National Institutes of Health.

Biotechnology and Interdisciplinary Studies at Rensselaer

At Rensselaer, faculty and students in diverse academic and research disciplines are collaborating at the intersection of the life sciences, the physical sciences, and engineering to encourage discovery and innovation. Rensselaer’s four biotechnology research constellations — biocatalysis and metabolic engineering, functional tissue engineering and regenerative medicine, biocomputation and bioinformatics, and integrative systems biology — engage a multidisciplinary mix of faculty and students focused on the application of engineering and physical and information sciences to the life sciences. Ranked among the world’s most advanced research facilities, the Center for Biotechnology and Interdisciplinary Studies at Rensselaer provides a state-of-the-art platform for collaborative research and world-class programs and symposia.

About Rensselaer

Rensselaer Polytechnic Institute, founded in 1824, is the nation’s oldest technological university. The university offers bachelor’s, master’s, and doctoral degrees in engineering, the sciences, information technology, architecture, management, and the humanities and social sciences. Institute programs serve undergraduates, graduate students, and working professionals around the world. Rensselaer faculty are known for pre-eminence in research conducted in a wide range of fields, with particular emphasis in biotechnology, nanotechnology, information technology, and the media arts and technology. The Institute is well known for its success in the transfer of technology from the laboratory to the marketplace so that new discoveries and inventions benefit human life, protect the environment, and strengthen economic development.
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PostPosted: Wed Feb 14, 2007 3:08 pm    Post subject: Microbiologists deal with very small organisms and play cruc Reply with quote

Microbiologists deal with very small organisms and play crucial roles in our lives
STAR SCIENCE By Cynthia T. Hedreyda, Ph.D.
The Philippine STAR 02/15/2007

(First of two parts)
Several years ago, the much talked about fatal cases of bloody diarrhea in the US were caused by eating Jack-in-the Box hamburgers contaminated with a bacterium called Escherichia coli strain O157. I heard then US President Bill Clinton, in a television interview, blame a virus for the death of the infected children. Even the US president got confused or was not aware that a bacterium is different from a virus. About four years ago, when I invited Professor Winnie Monsod (UP School of Economics and GMA 7) to be the keynote speaker of a national convention of Filipino microbiologists, she mentioned that she had to search the Internet for a crash course in microbiology before the convention. Last year, I was invited by former Quezon City Vice Mayor Charito Planas to be a resource person in her radio program where she introduced me as a microbiologist. She emphasized that it was the first time she had invited a microbiologist in her program and was interested to find out what microbiologists do. This was when I realized that there is an urgent need to promote the popular awareness of microbiology in the country. If outstanding and distinguished personalities like Prof. Monsod and Atty. Planas are not very familiar with basic microbiology and are not aware of what microbiologists do, then so much more for millions of Filipinos. How does one become a microbiologist? Where can we find microbiologists? What roles do they play in our community, the country, or the world in general?

Microbiology is the study of very small organisms (microorganisms) that could only be seen under the microscope. A microorganism may be made up of a tiny single cell (unicellular) like all bacteria, yeasts, and protozoa (amoeba, euglena, and paramecium). In the laboratory, several bacterial or yeast cells grouped together may be seen with the naked eye as a colony in an agar–based medium. Other species of microorganisms may be made up of more than one cell (multicellular) such as molds. Microbiology also includes the study of even smaller single entities (not cellular) called viruses, which contain nucleic acid (DNA or RNA) enclosed in a protein coat. Take note that there are useful bacteria, yeasts, and molds that are used to produce food, pharmaceutical, and industrial products. On the other hand, there are also species of bacteria, yeast, molds, protozoa and several viruses that are agents of plant, animal, and human diseases. A microbiologist, therefore, is someone who underwent formal education in microbiology or related fields and training to work with any of the above microscopic organisms and/or viruses. A microbiologist is expected to be knowledgeable in basic microbiology techniques for all microorganisms, but may have focused work and obtained expertise on just one to a few species of bacteria, yeast, mold or a particular type of virus.

A microbiologist may be a scientist in an academic and/or research institution performing basic research on a specific microorganism or group of microorganisms. Microbiology covers a wide range of topics such as microbial physiology, microbial ecology, medical microbiology, food microbiology, virology, and microbial genetics. Basic microbiology research aims to gain knowledge and information about microorganisms, without emphasis on immediate use or application. Basic microbiology research generates information about a microorganism’s structure, physiology, functions, and interactions (with members of the same species, with other species, or the environment). Basic microbiology research may be conducted to determine the ability of microorganisms to cause diseases, to arrive at species identification, to achieve characterization and to evaluate relatedness (phylogeny) and classification.

Microbiologists may also be involved in applied research using microorganisms toward the development of products and processes useful to man. Applied microbiology research may be conducted with any of the following objectives: to determine the ability of a microorganism to produce a useful product, to study the factors that favor microbial growth and efficient synthesis of the useful product, to generate a strain of microorganism with improved quality and/or quantity of product, to identify and eliminate the factors that will inhibit production, and to eradicate undesirable microorganisms that produce toxins or other unwanted products. Therefore, microbiologists may be interested in the growth and maintenance of live microbial cultures that produce desirable products or may be focused on preventing the growth of undesirable microorganisms such as those that cause undesirable flavors, food spoilage and plant and animal diseases.

There are agricultural microbiologists with formal education in agriculture but work with microorganisms that enhance plant growth or work with microorganisms that cause plant diseases. Veterinary microbiologists (veterinarians by profession) work with microorganisms that are causative agents of animal diseases. Most medical microbiologists work in hospitals and handle microorganisms that cause human diseases and may be medical technologists, physicians, or nurses by profession. Medical microbiologists are responsible for identifying microorganisms that cause human diseases, obtaining crucial information necessary to suggest the best way to eliminate the disease-causing agent. Medical microbiologists may also be tasked to determine microbial susceptibilities to drugs like antibiotics before doctors can recommend appropriate medication. Veterinary or medical microbiologists make use of killed and weakened (attenuated) disease-causing microorganisms or viruses to produce animal and human vaccines that result in protection against different infections. Food microbiologists are important in industries manufacturing different food products using microorganisms. Production of beer and wine, for instance, use the yeast Saccharomyces cerevisiae to produce the alcohol. Cheese production makes use of certain species of bacteria and fungi for cheese maturation and flavor formation. Food microbiologists may also be hired by companies involved in large-scale production of fermented products, including several traditional fermented foods like fermented vegetables (‘burong mustasa" and "kimchi") and fermented fish and shrimp ("bagoong," " alamang" and fish sauce). Other food microbiologists are responsible for ensuring food safety or absence of unwanted microbial contaminants or microbial toxins from processed food.

Environmental microbiologists are concerned with using microorganisms to degrade household, agricultural or industrial wastes which will otherwise result in polluted land areas and bodies of water, if left untreated. There are also aquatic microbiologists or marine microbiologists who work on microorganisms that infect economically important fishes, shrimps, seaweeds, corals, and other marine organisms. Industrial microbiologists are needed in several industries that rely on microbial enzymes, including companies that produce digestive aids, meat tenderizers, detergents, stain removers, and leather products. In addition to these, microbiologists are needed in companies producing microbial organic acids, dyes, antibiotics and amino acids. Microbiologists are even hired by companies making pharmaceutical and cosmetics where they are tasked to handle microorganisms that produce pharmaceutical products. Moreover, microbiologists are also responsible for quality control so that their products are free of microorganisms that may cause diseases or so that their claims of anti-microbial active ingredients are valid. Even airline companies hire microbiologists in order to ensure food safety of flight meals. In advanced countries, production of useful proteins by genetically improved microorganisms is conducted, including human insulin for diabetics, growth hormones, and anti-tumor factors.

Microbiologists may be trained to be teachers in high school or may decide to be mentors in college, responsible for educating young students on the principles of microbiology. These microbiology educators are instrumental in producing and training future microbiologists of the country. Some microbiology teachers are also involved in research and extension. There are microbiologists who have decided to be businessmen or biotechnologists, producing microbial-based products as cottage industries or at commercial scale. Still other microbiologists work in service diagnostic laboratories or work as sales representatives promoting products used in microbiology laboratories. Therefore, microbiologists are needed in schools and universities as teachers, in several biotechnology industries as entrepreneurs, in farms and aquaculture, in hospitals and diagnostic medical laboratories, and for environmental management. The demand for microbiologists is not at all dwindling through the years.

(To be concluded) * * *
Dr. Cynthia T. Hedreyda is a professor and the current director of the National Institute of Molecular Biology and Biotechnology, UP Diliman. She is an active member and former president of the Philippine Society for Microbiology Inc. (PSM, Inc. 2001-2002) and former chairwoman of PAM (2005-2006). She is actively involved in supervising student research in molecular microbiology and was recognized as PSM Outstanding Microbiologist in 2005. Dr. Hedreyda always finds time to organize and participate in scientific workshops and other activities to promote awareness of microbiology and biotechnology in the country. E-mail her at hedreyda@laguna.net.
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PostPosted: Wed Feb 21, 2007 3:20 pm    Post subject: Microbiologists deal with very small organisms and play cruc Reply with quote

Microbiologists deal with very small organisms and play crucial roles in our lives
STAR SCIENCE By Cynthia T. Hedreyda, Ph.D.
The Philippine STAR 02/22/2007

(Second of two parts)
How do you become a microbiologist? There are several possible routes to becoming a microbiologist. A direct route one may take is to obtain a Bachelor of Science degree in Microbiology or a Bachelor of Science degree in Biology with Microbiology as major. These programs, however, are only offered in about four institutions in the country. To be a more competent microbiologist, additional training and work experience with microorganisms after completing a BS degree are deemed necessary. Expertise in microbiology may also be further developed by seeking advanced degrees such as a MS and Ph.D in Microbiology here or abroad. There are also several opportunities for deserving young microbiologists to avail themselves of microbiology training abroad.

While it is true that only a few universities in the country offer BS, MS, and Ph.D in Microbiology, there are other routes to becoming a microbiologist. One may take BS Medical Technology and obtain additional training in microbiology to become a medical microbiologist. One can be a microbiologist by completing any BS degree in related fields like Agriculture, Food Science, Botany, Zoology, Chemistry, Environmental Science, etc., with microbiology as the minor and by working on microbiology after graduation. Additional microbiology training or degree will further enhance expertise in the field. Microbiologists need to undergo constant training and retooling for advanced techniques in order to get updated on new findings and procedures for the advancement of the profession. Therefore, one may have obtained education and expertise in a different field of science initially, but after training and relevant microbiology experience, one may find himself working on microorganisms and be considered a microbiologist. Constant retooling and updating are important for a microbiologist to be abreast with the fast advances in the field.

There are several microbiology-related professional organizations in the Philippines. The Philippine Society for Microbiology Inc. (PSM Inc.), for instance, boasts of over 3,000 members who are practicing microbiologists or are people in other fields but are very much interested in microbiology and biotechnology. To date PSM has three regional chapters: PSM Visayas, PSM Mindanao, and PSM Northern Luzon. PSM National and all three chapters hold annual scientific meetings for updating on new findings in the field. The societies also organize national and international symposia on microbiology topics. PSM hosts an international Asia-Pacific Biotechnology Congress every five years where microbiologists with different expertise from other countries are invited to participate. Other microbiology-related professional organizations with microbiologists among their members include the organization of medical technologists and an organization of health workers involved in infectious diseases. In addition to several microbiology-related societies, there is the Philippine Academy of Microbiology (PAM), an accreditation arm of PSM with Diplomates and Fellows who have qualified based on outstanding credentials in microbiology teaching, research, and extension as members. PAM has been responsible for evaluating and accreditation of Registered and Specialist Microbiologists in the country. To qualify for accreditation, one must exhibit enough knowledge on Basic Microbiology, Microbial Physiology, Microbial Ecology, Virology, Food Microbiology and Medical Microbiology by passing a comprehensive examination administered by PAM examiners.

I therefore encourage our young students to become microbiologists using any of the possible routes mentioned above. Microbiologists have the luxury of a wide range of job opportunities here and abroad. Most of all, being a microbiologist can be a very rewarding profession. Several microbial-based products have significantly contributed to agriculture and aquaculture. Advances in medicine and solutions to problems in animal and human health have relied heavily on the contributions of medical microbiology research. Microorganisms are still among the key players to address our past, present and future problems in our environment. Microbial-based industries are expected to significantly catalyze our attempts at nation-building.

Microbiologists are everywhere. Seek a microbiologist. You can easily find one because they are in schools, in farms, in the industry, and in hospitals. Talk and interact with them and learn more about microbiology and what a microbiologist can do for you. * * *
Dr. Cynthia T. Hedreyda is a professor and the current director of the National Institute of Molecular Biology and Biotechnology, UP Diliman. She is an active member and former president of the Philippine Society for Microbiology Inc. (PSM, Inc. 2001-2002) and former chairwoman of PAM (2005-2006). She is actively involved in supervising student research in molecular microbiology and was recognized as PSM Outstanding Microbiologist in 2005. Dr. Hedreyda always finds time to organize and participate in scientific workshops and other activities to promote awareness of microbiology and biotechnology in the country. E-mail her at hedreyda@laguna.net.
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PostPosted: Sat Feb 24, 2007 8:27 am    Post subject: MicrobeWorld Recognized by PR News and Association TRENDS Reply with quote

MicrobeWorld Recognized by PR News and Association TRENDS

The MicrobeWorld website and podcast have received two awards. The Association TRENDS 2006 All Media Contest presented MicrobeWorld with the Gold in the Web Site category for best design, interactivity and overall effectiveness. And, PR News’ 2006 Nonprofit PR Awards gave the MicrobeWorld Radio podcast an honorable mention in the Interactive PR/Marketing category.

http://www.microbeworld.org/
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PostPosted: Sat Mar 24, 2007 7:19 am    Post subject: 'Ancestral eve' was mother of all tooth decay Reply with quote

23-Mar-2007

New York University

'Ancestral eve' was mother of all tooth decay

NYUCD study finds humans and their oral bacteria evolved from a common African ancestor

A New York University College of Dentistry (NYUCD) research team has found the first oral bacterial evidence supporting the dispersal of modern Homo sapiens out of Africa to Asia.

The team, led by Page Caufield, a professor of cariology and comprehensive care at NYUCD, discovered that Streptoccocus mutans, a bacterium associated with dental caries, has evolved along with its human hosts in a clear line that can be traced back to a single common ancestor who lived in Africa between 100,000 and 200,000 years ago.

S. mutans is transmitted from mothers to infants, and first appears in an infant’s mouth at about two years of age. Caufield’s findings are reported in an article in the February issue of the Journal of Bacteriology.

In his analysis of the bacterium, Caufield used DNA fingerprints and other biomarkers that scientists have also employed to trace human evolution back to a single common African ancestor, known as "ancestral Eve."

"As humans migrated around the world and evolved into the different races and ethnicities we know today," Caufield said, "this oral bacterium evolved with them in a simultaneous process called coevolution."

"It is relatively easy to trace the evolution of S. mutans, since it reproduces through simple cell division," says Caufield, who gathered over 600 samples of the bacterium on six continents over the past two decades. His final analysis focused on over 60 strains of S. mutans collected from Chinese and Japanese; Africans; African-Americans and Hispanics in the United States; Caucasians in the United States, Sweden, and Australia; and Amazon Indians in Brazil and Guyana.

"By tracing the DNA lineages of these strains," Caufield said, "We have constructed an evolutionary family tree with its roots in Africa and its main branch extending to Asia. A second branch, extending from Asia back to Europe, traces the migration of a small group of Asians who founded at least one group of modern-day Caucasians."

Additional branches, tracing the coevolution of humans and bacteria from Asia into North and South America, will be drawn in the next phase of Caufield’s analysis.

###
Caufield’s coauthors were Deepak Saxena, adjunct associate professor of basic science and craniofacial biology; Yihong Li, associate professor of basic science and craniofacial biology, both at NYU College of Dentistry; and David Fitch, an associate professor in NYU’s Department of Biology.

Editor’s Note:

Founded in 1865, New York University College of Dentistry (NYUCD) is the third oldest and the largest dental school in the United States, educating more than 8 percent of all dentists. NYUCD has a significant global reach and provides a level of national and international diversity among its students that is unmatched by any other dental school.
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PostPosted: Fri Apr 06, 2007 7:07 am    Post subject: Scientists decode genome of oral pathogen Reply with quote

Scientists decode genome of oral pathogen
Virginia Commonwealth University
6 April 2007

Virginia Commonwealth University researchers have decoded the genome of a bacteria normally present in the healthy human mouth that can cause a deadly heart infection if it enters the bloodstream.

The finding enables scientists to better understand the organism, Streptococcus sanguinis, and develop new strategies for treatment and infection prevention.

S. sanguinis, a type of bacteria that is naturally present in the mouth, is among a variety of microorganisms responsible for the formation of dental plaque. In general, S. sanguinis is harmless. However, if it enters the bloodstream, possibly through a minor cut or wound in the mouth, it can cause bacterial endocarditis, a serious and often lethal infection of the heart.

For the full article:

http://www.news.vcu.edu/news.a.....p;nid=2013
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PostPosted: Mon Apr 16, 2007 9:51 am    Post subject: Rapid, one-step, ultra-sensitive detection of food poisoning Reply with quote

Rapid, one-step, ultra-sensitive detection of food poisoning bacteria and biothreats
16 April 2007
Analytical Chemistry

A new mosquito-sized biosensor can detect amazingly small amounts of disease-causing E. coli bacteria in food in a single-step process that takes only minutes, compared to hours required with conventional tests for that common food poisoning agent, researchers in Philadelphia are reporting. The sensor also can quickly detect proteins important in medical diagnostic testing and very low levels of biothreats such as anthrax, according to the study, published in the current (April 1) edition of ACS’ Analytical Chemistry, a semi-monthly journal.

In the study, Raj Mutharasan and colleagues point out that rapid measurements of very low concentrations of pathogens and proteins could have wide application in medical diagnostic testing, monitoring for biothreat agents, detecting contaminated food products and other areas. Existing tests for low-level pathogens, however, take time because they require a step to boost the concentration of microbes in a sample. No direct test currently exists for low-levels of proteins, the report adds.

The study describes use of the biosensor to detect E. coli in ground beef and other materials at some of the lowest concentrations ever reported. At the heart of the new biosensor is a vibrating cantilever, with a tiny beam supported at one end and coated with antibodies at its other, free-moving end. The antibodies are specific to the material being detected, such as E. coli, anthrax or proteins that are biomarkers for disease. When that antigen is present in a sample flowing through the biosensor, it binds to the cantilever and alters the frequency of vibration in a way that can be detected electronically.

ARTICLE #4 FOR IMMEDIATE RELEASE
"Method for Label-Free Detection of Femtogram Quantities of Biologics in Flowing Liquid Samples"

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http://pubs.acs.org/cgi-bin/sa.....621726.pdf

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PostPosted: Mon Jun 04, 2007 11:11 am    Post subject: E. coli Thrives in Beach Sands Reply with quote

E. coli Thrives in Beach Sands
By Andrea Thompson, LiveScience Staff Writer

posted: 04 June 2007 09:33 am ET

The perils of a day at the beach aren’t always as easy to see as riptides, broken shells and jellyfish—the sand at the shore may harbor E. coli and other potentially dangerous disease-causing bacteria, a recent study showed.

E. coli is one of the main species of bacteria that live in the lower intestines of mammals, including humans—one person excretes billions of them in a day. Pathogenic strains of E. coli can cause vomiting and diarrhea.

Government testers look for E. coli as an indicator of fecal contamination at freshwater beaches all over the country, because the other microbes present are more difficult to detect (another bacteria is used to test for fecal matter at ocean beaches because E. coli does not survive well in salt water).

Beaches all over the country frequently close due to fecal contamination; a day at the beach can be ruined if septic systems overflow or malfunction, or if a lot of birds happen to be in the neighborhood.

For the full article:

http://www.livescience.com/hea.....ecoli.html
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PostPosted: Mon Jun 11, 2007 1:30 pm    Post subject: Food safety begins as vegetables grow Reply with quote

American Phytopathological Society

Food safety begins as vegetables grow

St. Paul, Minn. (June 11, 2007) - Monitoring vegetables while they are growing is crucial in the prevention of contamination of fresh produce with harmful bacteria such as E. coli and Salmonella, say plant pathologists who are members of The American Phytopathological Society (APS).

There have been outbreaks of E. coli and Salmonella for at least the past decade, and the incidences of vegetable contamination are increasing in frequency. "We've studied plant pathogens on plants for a long time, but haven’t studied human pathogens on plants until recently," said Jeri D. Barak, research microbiologist with the U.S. Department of Agriculture's Agricultural Research Service (ARS) in Albany, Calif.

"What we've found up to this point is that most contamination is occurring while the plants are still growing in the field," said Barak. "The most successful way to prevent contamination of fresh produce is to intervene before the harvest, not after," she said.

Her research has shown that pathogens like Salmonella use specific genes to colonize plants, creating an active interaction with the plant surface. "When this happens, the bacteria become almost inseparable from the vegetable," she said.

Barak and other APS members will present their latest food safety research and describe future research needs at a symposium titled "Cross Domain: Emerging Threats to Plants, Humans, and Our Food Supply" on Monday, July 30 from 1 to 5 p.m. These experts from across the United States will discuss the environmental biology of bacteria in fresh produce and the link between plants and bacteria associated with human infections, such as the recent E. coli outbreaks from California spinach.

The symposium will be held during the joint meeting of The American Phytopathological Society (APS) and the Society of Nematologists (SON). The meeting will take place July 28 – August 1, 2007, at the Town and Country Resort and Convention Center in San Diego, Calif.

A news conference on plant diseases and issues that are of importance to the California economy and agriculture, including the latest food safety information, will be held during the meeting on Monday, July 30 at 11 a.m.


###
More information on the meeting is available at http://meeting.apsnet.org. Members of the media are extended complimentary registration to the meeting. To register, contact Amy Steigman at asteigman@scisoc.org or +1.651.994.3802.

The American Phytopathological Society (APS) is a non-profit, professional scientific organization. The research of the organization's 5,000 worldwide members advances the understanding of the science of plant pathology and its application to plant health. The Society of Nematologists (SON) is an international organization formed to advance the science of nematology in both its fundamental and economic aspects.
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PostPosted: Fri Jun 15, 2007 12:53 pm    Post subject: Vacuum-packed Foods Breed Deadly Bacteria Reply with quote

Vacuum-packed Foods Breed Deadly Bacteria
By Charles Q. Choi, Special to LiveScience

posted: 14 June 2007 07:00 pm ET

Those sealed glossy packs of cheeses and lunchmeat on your grocer's shelf can provide a particularly friendly home for nasty bugs that cause food poisoning, new research shows.

Vacuum-packed foods are deprived of oxygen to keep them fresh and boost their shelf life, but the same strategy is a boon for Listeria monocytogenes, a bacterium responsible for a kind of food poisoning that kills 25 percent of the people it infects.

Unlike many other food-borne germs, Listeria can grow even in the cold temperatures of refrigerators. The U.S. Food and Drug Administration notes that the microbe has been linked with foods such as raw milk; ice cream; soft-ripened cheeses such as feta, Brie and Camembert; hot dogs; raw and deli meats; raw vegetables; raw and cooked poultry; and raw and smoked fish.

For the full article:

http://www.livescience.com/hea.....teria.html
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PostPosted: Fri Jul 27, 2007 8:22 am    Post subject: Strange New Microbe Harvests Sunlight Reply with quote

Strange New Microbe Harvests Sunlight
By Jeanna Bryner, LiveScience Staff Writer

posted: 26 July 2007 03:03 pm ET

Yellowstone's hot springs are known to harbor extreme creatures that paint the water shades of red, orange and green. Now scientists have discovered a new type of bacteria with light-harvesting antennae.

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http://www.livescience.com/str.....teria.html
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PostPosted: Mon Dec 10, 2007 1:56 pm    Post subject: Toward a Rosetta Stone for Microbes’ Secret Language Reply with quote

Toward a Rosetta Stone for Microbes’ Secret Language
10 December 2007
ACS Chemical Biology

Scientists are on the verge of decoding the special chemical language that bacteria use to “talk” to each other, British researchers report in a commentary article that appeared in the November issue of ACS Chemical Biology, a monthly journal. That achievement could lead to new treatments for antibiotic-resistant bacteria, including so-called superbugs that infect more than 90,000 people in the United States each year, they note.

David Spring, Martin Welch, and James T. Hodgkinson explain that researchers long have known that bacteria communicate with each other. Microbes release small molecules that enable millions of individuals in a population to coordinate their behavior. Disease-causing bacteria use this language to decide when to infect a person or other host. Decoding the structure and function of compounds involved in this elaborate signaling process, known as “quorum sensing,” could lead to new medicines to block the signals and prevent infections.

The report describes development of a group of powerful compounds, called N-acylated homoserine lactone (AHL) analogues that are effective against a broad-range of bacterial types, including those that cause diseases in humans. These compounds are “some of the most potent synthetic modulators of quorum sensing” identified to date, they say. In addition to showing promise for fighting antibiotic-resistant infections, the compounds may help prevent the growth of biofilms that foul medical implants and cause tooth decay and gum disease, the scientists note.

ARTICLE #3 FOR IMMEDIATE RELEASE
“Learning the Language of Bacteria”

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