From insects to man: identification of virulence factors involved in the adaptation of the emerging pathogen Photorhabdus asymbiotica to human hosts

Abstract number: 1733_565

Forquin M., Esque J., Pimenta A.

Photorhabdus are entomopathogenic bacteria currently used for the biological control of crop pests. Recently, an increasing number of Photorhabdus strains have been isolated from human clinical specimens, associated with locally invasive soft tissue infections and disseminated bacteraemia.

Objectives: In view of their growing use in biological control, which increases the human potential rate of exposure to these pathogens, we undertook a comparative study between insect and human pathogenic strains of Photorhabdus, in an attempt to understand the genetic mechanisms involved in their recently acquired capacity to infect humans.

Methods: Three Photorhabdus strains, two human (P. asymbiotica SN and ATCC43949) and one insect pathogen (Photorhabdus sp Q617), were tested for their ability to bind to two major components of the human extracellular matrix (ECM), fibronectin (Fn) and vitronectin (Vn), to infect or invade human epithelial cells in culture, and to interact with the cellular cytoskeleton. Adherence, infection and invasion experiments were performed in 96-well microtiter plates coated either with Fn, Vn or with monolayers of human epithelial HaCaT cells. Bacterial invasion was quantified by the gentamicin survival assay. In inhibition assays, anti-Fn, anti-Vn antibodies, or genistein were added to epithelial cell monolayers. For immunofluorescence, HaCaT monolayers on glass coverslips were infected and labelled with phalloidine-TRITC and DAPI.

Results: Only P. asymbiotica human pathogenic isolates ATCC43949 and SN were able to adhere to human fibronectin and/or vitronectin, and to infect/invade HaCaT cells. This was inhibited in the presence of antibodies against human Fn or Vn. Only strain ATCC43949 induced cytotoxic effects after 6h co-culture with human cells. Cytoskeleton involvement in the P. asymbiotica infective process was indicated by blockage of infection and invasion by genistein, and by immunofluorescence analysis of infected cells.

Conclusion: The acquisition of virulence factors enabling P. asymbiotica to interact with human ECM and to human cells is a key factor in its evolution towards the colonisation of human hosts. ECM proteins are involved in the primary events during P. asymbiotica colonisation of human epithelial tissues, and the host cytoskeleton is solicited during the P. asymbiotica-epithelial cells interaction. Possible mechanisms used by P. asymbiotica to colonise human tissues are discussed.

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Taking a Closer Look at the Stories Ignored by the Mainstream Media

One of the great mysteries surrounding the spread of GMO plants around the world since the first commercial crops were released in the early 1990’s in the USA and Argentina has been the absence of independent scientific studies of possible long-term effects of a diet of GMO plants on humans or even rats. Now it has come to light the real reason. The GMO agribusiness companies like Monsanto, BASF, Pioneer, Syngenta and others prohibit independent research.



An editorial in the respected American scientific monthly magazine, Scientific American, August 2009 reveals the shocking and alarming reality behind the proliferation of GMO products throughout the food chain of the planet since 1994. There are no independent scientific studies published in any reputed scientific journal in the world for one simple reason. It is impossible to independently verify that GMO crops such as Monsanto Roundup Ready Soybeans or MON8110 GMO maize perform as the company claims, or that, as the company also claims, that they have no harmful side effects because the GMO companies forbid such tests!



That’s right. As a precondition to buy seeds, either to plant for crops or to use in research study, Monsanto and the gene giant companies must first sign an End User Agreement with the company. For the past decade, the period when the greatest proliferation of GMO seeds in agriculture has taken place, Monsanto, Pioneer (DuPont) and Syngenta require anyone buying their GMO seeds to sign an agreement that explicitly forbids that the seeds be used for any independent research. Scientists are prohibited from testing a seed to explore under what conditions it flourishes or even fails. They cannot compare any characteristics of the GMO seed with any other GMO or non-GMO seeds from another company. Most alarming, they are prohibited from examining whether the genetically modified crops lead to unintended side-effects either in the environment or in animals or humans.



The only research which is permitted to be published in reputable scientific peer-reviewed journals are studies which have been pre-approved by Monsanto and the other industry GMO firms.



The entire process by which GMO seeds have been approved in the United States, beginning with the proclamation by then President George H.W. Bush in 1992, on request of Monsanto, that no special Government tests of safety for GMO seeds would be conducted because they were deemed by the President to be “substantially equivalent” to non-GMO seeds, has been riddled with special interest corruption. Former attorneys for Monsanto were appointed responsible in EPA and FDA for rules governing GMO seeds as but one example and no Government tests of GMO seed safety to date have been carried out. All tests are provided to the US Government on GMO safety or performance by the companies themselves such as Monsanto. Little wonder that GMO sounds to positive and that Monsanto and others can falsely claim GMO is the “solution to world hunger.”



In the United States a group of twenty four leading university corn insect scientists have written to the US Government Environmental Protection Agency (EPA) demanding the EPA force a change to the company censorship practice. It is as if Chevrolet or Tata Motors or Fiat tried to censor comparative crash tests of their cars in Consumer Reports or a comparable consumer publication because they did not like the test results. Only this deals with the human and animal food chain. The scientists rightly argue to EPA that food safety and environment protection “depend on making plant products available to regular scientific scrutiny.” We should think twice before we eat that next box of American breakfast cereal if the corn used is GMO .


F. William Engdahl is author of Full Spectrum Dominance: Totalitarian Democracy in the New World Order. He may be contacted via his website at www.engdahl.oilgeopolitics.net.
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Taking a Closer Look at the Stories Ignored by the Mainstream Media

By Jeffrey M. Smith
7-22-9

The American Academy of Environmental Medicine states,"Genetically Modified foods have not been properly tested and pose a serious health risk. There is more than a casual association between GM foods and adverse health effects. There is causation." Last May the American Academy of Environmental Medicine (AAEM) called on "Physicians to educate their patients, the medical community, and the public to avoid GM (genetically modified) foods when possible and provide educational materials concerning GM foods and health risks." They called for a moratorium on GM foods, long-term independent studies, and labeling. AAEM's position paper stated, "Several animal studies indicate serious health risks associated with GM food," including infertility, immune problems, accelerated aging, insulin regulation, and changes in major organs and the gastrointestinal system. They conclude, "There is more than a casual association between GM foods and adverse health effects. There is causation," as defined by recognized scientific criteria. "The strength of association and consistency between GM foods and disease is confirmed in several animal studies." More and more doctors are already prescribing GM-free diets. Dr. Amy Dean, a Michigan internal medicine specialist, and board member of AAEM says, "I strongly recommend patients eat strictly non-genetically modified foods." Ohio allergist Dr. John Boyles says "I used to test for soy allergies all the time, but now that soy is genetically engineered, it is so dangerous that I tell people never to eat it." Dr. Jennifer Armstrong, President of AAEM, says, "Physicians are probably seeing the effects in their patients, but need to know how to ask the right questions." World renowned biologist Pushpa M. Bhargava goes one step further. After reviewing more than 600 scientific journals, he concludes that genetically modified organisms (GMOs) are a major contributor to the sharply deteriorating health of Americans. Among the population, biologist David Schubert of the Salk Institute warns that "children are the most likely to be adversely effected by toxins and other dietary problems" related to GM foods. He says without adequate studies, the children become "the experimental animals."

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Taking a Closer Look at the Stories Ignored by the Mainstream Media