C weapons are recent acquisitions in humankind’s ever-growing arsenal of destruction. But bacteria and fungi have been practicing chemical warfare for a very long time. Among the numerous and structurally diverse antimicrobial agents that microbes produce are penicillin by the mold Penicillium notatum, many important antibiotics by streptomycetes, a wide range of bacteriocins by Escherichia col...

Chrysciova quinquecirrha, the common sea nettle infests the Chesapeake Bay waters during the summer season. This coelenterate causes a severe economic problem for this resort area because of the painful sting it iaflicts upon bathers who accidentally come in contact with its tentacles. These stings are thought to result from the injection of nematocyst threads and the introduction of a toxin in...

Toxin-antitoxin (TA) systems are small genetic elements found in the majority of prokaryotes. They encode toxin proteins that interfere with vital cellular functions and are counteracted by antitoxins. Dependent on the chemical nature of the antitoxins (protein or RNA) and how they control the activity of the toxin, TA systems are currently divided into six different types. Genes comprising the...

Bacillus thuringiensis (Bt) Cry toxins are used to control Aedes aegypti, an important vector of dengue fever and yellow fever. Bt Cry toxin forms pores in the gut cells, provoking larvae death by osmotic shock. Little is known, however, about the endocytic and/or degradative cell processes that may counteract the toxin action at low doses. The purpose of this work is to describe the mechanisms...

Toxoid vaccines--vaccines based on inactivated bacterial toxins--are routinely used to promote antitoxin immunity for the treatment and prevention of bacterial infections. Following chemical or heat denaturation, inactivated toxins can be administered to mount toxin-specific immune responses. However, retaining faithful antigenic presentation while removing toxin virulence remains a major chall...

The Cry proteins produced by Bacillus thuringiensis (Bt) are the most widely used biopesticides effective against a range of crop pests and disease vectors. Like chemical pesticides, development of resistance is the primary threat to the long-term efficacy of Bt toxins. Recently discovered cadherin-based Bt Cry synergists showed the potential to augment resistance management by improving effica...

Stationary liquid cultures of Fusarium tricinctum NRRL 3299 (synonym: F. sporotrichioides) produce T-2 toxin, neosolaniol, diacetoxyscirpenol, and HT-2 toxin when cultured on peptone-enriched Czapek Dox medium. At 15 and 27 degrees C, maximum T-2 toxin yield (265 and 50 mug/ml) was found after 10 to 14 and 7 days, respectively. The T-2 toxin in the culture medium was metabolized rapidly at 27 d...

Many isolates of the same species display qualitatively similar toxin profiles supporting the view that toxin production is heritable, at least for PSP toxin producers (see Cembella and John, Chap. 17). It is not known, however, why some phytoplankton species produce toxins while most do not, or perhaps more perplexing, why some strains of the same species are toxic while others are not. One ma...

Recently, using structure-inspired drug design, we demonstrated that aminoalkyl derivatives of beta-cyclodextrin inhibited anthrax lethal toxin action by blocking the transmembrane pore formed by the protective antigen (PA) subunit of the toxin. In the present study, we evaluate a series of new beta-cyclodextrin derivatives with the goal of identifying potent inhibitors of anthrax toxins. Newly...

designing and producing a proper fusion construction is the most important problem of producing large quantities of a properly folded functional protein. this construction should have all necessary components of a real gene. a good designed fusion gene construction could be cloned into a good and suitable host. clostridium perfringens is an important pathogen of humans and livestock and produce...