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Post by skyship on Jun 27, 2009 10:20:30 GMT -5
This is important and the crystals do form into pathogens. www.scientificamerican.com/article.cfm?id=weed-whacking-herbicide-pSaw it in my hair, wrap right around it and begin to grow. this is from the cryotechnology. Freezedried larvae forms into pathogenic forms or nematode larvae from Steinerema or others. I have a list. From Parasitoid wasp, dev. inside. like the fig wasp, Pack a powerful punch. Skytroll
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Post by aqt on Jun 27, 2009 15:36:38 GMT -5
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Post by aqt on Jun 27, 2009 15:41:07 GMT -5
These data agrees with the 200-fold higher apparent affinity of the oligomer than that of the monomer to an APN enriched protein extract. Our data suggest that the two receptors interact sequentially with different structural species of the toxin leading to its efficient membrane insertion.www.ncbi.nlm.nih.gov/pubmed/15533304Oligomerization triggers binding of a Bacillus thuringiensis Cry1Ab pore-forming toxin to aminopeptidase N receptor leading to insertion into membrane microdomains
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Post by aqt on Jun 27, 2009 15:44:48 GMT -5
The crystal protein is produced during sporulation and is accumulated both as an inclusion and as part of the spore coat. The toxic segment of the protein is located in the N-terminus. Promotes colloidosmotic lysis by binding to the midgut epithelial cells of many lepidopteran larvae. www.abcam.com/Bacillus-thuringiensis-CRY1Ab-Toxin-antibody-ab51586.html
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Post by aqt on Jun 27, 2009 16:09:01 GMT -5
how do ya like me now?....LOLOLOL Human Cell Exposure Assays of Bacillus thuringiensis Commercial Insecticides: Production of Bacillus cereus-Like Cytolytic Effects from Outgrowth of Spores www.ehponline.org/members/2000/108p919-930tayabali/tayabali-full.htmlThe results presented here show for the first time that, at the human cell level, both Bti and Btk BT products can generate potent B. cereus-like toxic effects. To go beyond the scale seen in BT product immunologic sensitization reactions of field workers (3), a sustained infection would be needed to generate sufficient amounts of vegetative cells and their cytolytic exoproducts. What is lacking is a critical understanding of conditions that might concern high-risk groups, those unable to manage microbe invasions through impaired immune responses and other physical-chemical clearance mechanisms manifested during development (the very young, the elderly) and in specific genetic disorders (e.g., cystic fibrosis). To justify urban usage of spore-containing BT products, earlier claims of no health effects need to be addressed in terms of current medical views and practices (3,13). This includes testing health effects of vegetative cell exoproducts such as CryV (58) and Vip3A (59), which are proposed for use as novel insecticides.
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Post by aqt on Jun 27, 2009 16:19:27 GMT -5
spore and crystal mixture? ?? whoa!! what a combo....we have both. A Brazilian Bacillus thuringiensis strain highly active to sugarcane borer Diatraea saccharalis ( Lepidoptera: Crambidae) Bioinsecticides based either on a spore and crystal mixture or the heterologous expression of cry genes in microorganisms (18, 31) as well as in plants (33) have been efficiently used for controlling important agricultural pests and mosquitoes. www.scielo.br/scielo.php?script=sci_arttext&pid=S1517-83822007000300028
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Post by aqt on Jun 27, 2009 16:20:16 GMT -5
Bacillus thuringiensis This bacterium forms the major part of my research interests. It is a Gram positive spore-former that synthesizes a large cytoplasmic crystal containing insecticidal toxins. We are interested in the mechanism of in vivo crystallisation, the mechanism of action of the toxin within the insect gut, and the ways in which insects develop resistance to the toxins www.lifesci.sussex.ac.uk/home/Neil_Crickmore/
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Post by aqt on Jun 27, 2009 16:24:39 GMT -5
A common characteristic of the cry genes is their expression during the stationary phase. Their products generally accumulate in the mother cell compartment to form a crystal inclusion that can account for 20-30% of the dry weight of the sporulated cells. The high level of synthesis and coordination with the stationary phase are controlled by a variety of mechanisms occurring at the transcriptional, posttranscriptional and posttranslational levels. (1) www.mrc-lmb.cam.ac.uk/genomes/madanm/articles/dnashuff.htmAt the posttranslational level, these proteins form crystalline inclusions in the mother cell compartment. Depending on the protoxin composition, the crystals have various forms. This ability to crystallize helps in protecting the protein itself from premature proteolytic degradation.
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Post by aqt on Jun 27, 2009 16:33:08 GMT -5
The insecticidal crystals are composed of a large protein that is essentially inactive. When a caterpillar ingests some of the insecticidal crystals, the alkaline reducing conditions of the insects midgut cause the crystals to dissociate and release the crystal protein. At this stage the protein toxin is inactive, but specific proteases within the gastric juices of the insect chop the protein down to its protease resistant core that isnow fully active. This activated insecticidal protein then binds to a specific receptor on the brush border membranes of the cells lining the midgut and inserts itself into the cells membrane. When about eight of these aggregate together, they form a pore or channel through the membrane, and allow the cell contents to leak out (Figure 3.) causing the death of the cells essential for nutrient absorption. The insects rapidly stop feeding and eventually starve to death or die from secondary bacterial infections within about 24 hours. The processes of crystal solublisation, proteolytic processing to an active insecticidal protein and the binding to a specific receptor, all make the BT proteins highly specific and very desirable from an environmental perspective www.cottoncrc.org.au/content/Communities/Cotton_Info/The_Science_behind_Transgenic_cotton.aspx
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