Guest guest Posted June 16, 2004 Report Share Posted June 16, 2004 16 Jun 2004 14:48:25 -0000 Superbug with Anthrax Genes press-release The Institute of Science in Society Science Society Sustainability http://www.i-sis.org.uk General Enquiries sam Website/Mailing List press-release ISIS Director m.w.ho ======================================================== ISIS Press Release 16/06/04 Superbug with Anthrax Genes *************************** The Bacillus species causing anthrax and food poisoning are closely related to each other and to a third, Bacillus thuringiensis, whose toxin genes are extensively exploited to create genetically modified Bt- crops. ISIS has warned of the potential for dangerous recombinants to emerge; such a recombinant has now been identified. Dr. Mae-Wan Ho and Prof. Joe Cummins caution against growing Bt crops, especially in the Third World. A fully referenced (http://www.i-sis.org.uk/full/SWAGFull.php) version of this article is posted on ISIS Members' website. Full details here (http://www.i-sis.org.uk/membership.php) The three Bacillus bacteria all live in the soil and are so closely related that they may as well be regarded as a single species. B. anthracis, causes anthrax, B. cereus is linked to food poisoning, and B. thuriengiensis is extensively exploited as biopesticides in genetically engineered Bt crops, now widely cultivated in the United States, and increasingly being promoted in Third World countries. The three bacteria readily mate with one another and exchange plasmids (circular pieces of DNA) carrying specific toxin and virulence genes. They share very similar viruses (phages) that can integrate into the bacterial genome as 'prophage', and can hence also move toxin and virulence genes among them, many of them reside in the bacterial chromosome. Cummins has warned that dangerous recombinants could arise, from gene exchange between the bacteria and between the Bt plant debris and bacteria in the soil. Now, an international team of infectious disease researchers led by Claire M. Fraser of the Centers for Disease Control and Prevention (CDC) in Atlanta, Georgia, USA, have identified a recombinant between B. anthracis and B. cereus. They were alerted last year when two hospital patients in Texas died of severe pneumonia that appeared to be caused by inhalation anthrax, but neither patient was infected with B. anthracis. Instead, DNA tests showed that both patients were infected by a strain of B. cereus that normally causes mild food poisoning, which has somehow acquired the lethal anthrax genes. When the Texas cases came to light, the CDC scientists were sequencing a strain of B. cereus isolated from a man in Louisiana who, in 1994, showed up with severe anthrax-like symptoms. The Texas and Lousiana patients were all metal workers who seemed to have inhaled the bacteria. Anthrax is an acute fatal disease among mammals and B. anthracis became widely known as a biological weapon soon after September 11, 2001. It has two plasmids: pXO1 carrying the lethal toxin complex (edema factor, lethal factor and protective antigen), and pXO2 carrying the glutamic acid polymer that inhibits white blood cells from engulfing and digesting the bacterium. Until a few years ago, B. anthracis was thought to be distinct from B. cereus, because they look different and causes different diseases. The researchers sequenced the B. cereus genome using draft genome sequences obtained and assembled by the company Celera, and the resulting sequence annotated through The Institute for Genomic Research (TIGR) Bioinformatics pipeline, set up by Craig Venter, the maverick scientist who founded Celera to sequence the human genome, succeeded only too well, and was sacked from the company in January 2002, after he remarked on there being too few genes to support the simplistic idea that organisms are hardwired in their genes. It turns out that the culprit strain of B. cereus G9241 had acquired a plasmid very similar to the pXO1 of B. anthracis. In addition, analysis of seven other metabolic genes showed that the strain is closely related to, albeit distinct from B. anthracis. The sequence of B. cereus G9241 genome reveals a mosaic structure, which could be due to the presence of a great number of what appears to be known and novel mobile genetic elements that can insert sequences from other sources. It also has a 119 110bp circular plasmid with high similarity to B. anthracis pXO1. There is, further, a cryptic phage of 29 886bp that encodes phage-like proteins and a plasmid replicon (replicating unit) similar to B. anthracis plasmid pXO2. It also carries genes that, if functional, should provide the strain with resistance to b- lactam, chloramphenicol and macrolide antimicrobial agents. When injected into mice, B. cereus G9241 proved to be 100% lethal, as was B. anthracis, but it killed the mice almost twice as fast. All the mice injected with an ordinary B. cereus strain survived the experiment. As a result of these findings, the researchers concluded that, " it may not be appropriate to consider B. anthracis, as currently defined, as the only species capable of causing inhalation anthrax-like disease. " Another noteworthy feature is that at least two isolates of B. cereus (ATCC 14579) and M 1550) are extremely closely related to and cluster with B. thuringiensis. A number of delta endotoxins from B. thuringiensis strains are implicated in allergies and other illnesses, or known to be immunogenic. What sort of disease agent might emerge from B. cereus if it acquired endotoxin genes either from B. thuringiensis or from Bt crop debris in the soil? This question is especially pertinent in view of the substantial changes in the genetically modified Bt genes that are completely untested and hence unknown in toxicities. Countries, especially those in the Third World, where farmers live next to their fields, should be particularly wary about growing Bt crops ======================================================== This article can be found on the I-SIS website at http://www.i-sis.org.uk/SWAG.php If you like this original article from the Institute of Science in Society, and would like to continue receiving articles of this calibre, please consider making a donation or purchase on our website http://www.i-sis.org.uk/donations. ISIS is an independent, not-for-profit organisation dedicated to providing critical public information on cutting edge science, and to promoting social accountability and ecological sustainability in science. If you would prefer to receive future mailings as HTML please let us know. If you would like to be removed from our mailing list at http://www.i-sis.org.uk/mailinglist/.php ======================================================== CONTACT DETAILS The Institute of Science in Society, PO Box 32097, London NW1 OXR telephone: [44 20 8643 0681] [44 20 7383 3376] [44 20 7272 5636] General Enquiries sam Website/Mailing List press-release ISIS Director m.w.ho MATERIAL IN THIS EMAIL MAY BE REPRODUCED IN ANY FORM WITHOUT PERMISSION, ON CONDITION THAT IT IS ACCREDITED ACCORDINGLY AND CONTAINS A LINK TO http://www.i-sis.org.uk/ Quote Link to comment Share on other sites More sharing options...
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