Tightly Bound Binary Toxin in the Cell Wall of Bacillus sphaericus

We have shown that urea-extracted cell wall of entomopathogenic Bacillus sphaericus 2297 and some other strains is a potent larvicide against Culex pipiens mosquitoes, with 50% lethal concentrations comparable to that of the well-known B. sphaericus binary toxin, with which it acts synergistically. The wall toxicity develops in B. sphaericus 2297 cultures during the late logarithmic stage, earlier than the appearance of the binary toxin crystal. It disappears with sporulation when the binary toxin activity reaches its peak. Disruption of the gene for the 42-kDa protein (P42) of the binary toxin abolishes both cell wall toxicity and crystal formation. However, the cell wall of B. sphaericus 2297, lacking P42, kills C. pipiens larvae when mixed with Escherichia coli cells expressing P42. Thus, the cell wall toxicity in strongly toxic B. sphaericus strains must be attributed to the presence in the cell wall of tightly bound 51-kDa (P51) and P42 binary toxin proteins. The synergism between binary toxin crystals and urea-treated cell wall preparations reflects suboptimal distribution of binary toxin subunits in both compartments. Binary toxin crystal is slightly deficient in P51, while cell wall is lacking in P42

Development of the mathematical model of fuel equipment and justification for diagnosing diesel engines by injector needle displacement

This article discusses the proposed method for diagnosing diesel fuel equipment. An analysis of available methods for diagnosing fuel equipment has been carried out. The authors describe their method for diagnosing plunger pairs of a highpressure fuel pump according to the parameter of displacement of the injector needle. The design of the diagnostic device for measuring the movement of the injector needle has been developed and patented. The dependence of the maximum displacement of the injector needle on the increase, due to wear, of the radial clearance of the plunger bushing at the minimum steady state of idling of the engine has been determined. The technique of diagnosing the technical condition of plunger pairs of a high-pressure fuel pump by injector needle displacement is considered in detail