No abstract

For the biopesticide, the observed decline in detectable protein was due to biological factors, possibly including the germination of B. thuringiensis spores, and was favoured by higher temperature. In contrast, for purified proteins, the decline in detectable protein was slower at low temperature, probably because the conformational changes of the soil-adsorbed protein, which cause fixation and hence reduced extraction efficiency, are temperature dependent. © 2016 Society of Chemical Industry.

Summary The use of insecticidal proteins known as Cry or Bt, either as biopesticides used in agriculture or as vector control or originating from commercial genetically modified crops (GM), is increasing rapidly. The fate of these proteins in the environment depends strongly on their adsorption on the organo–mineral complexes of soil. Environmental monitoring requires the quantification of the proteins and this entails their chemical extraction from soil. Three Cry proteins, Cry1Ac, Cry1C and Cry2A, present in commercial biopesticide formulations or synthesized by GM plants or both were studied. The adsorption of trace amounts of Cry proteins on over 40 types of soil with contrasting properties was measured in dilute suspension. After a short incubation the extraction yield was measured with a previously tested alkaline solution that contained surfactant and another protein. Each of the proteins had a strong affinity for soil. No soil property was observed to determine either the affinity for soil or the extraction yield. There was no simple relation between the affinity (assessed from the distribution coefficient, Kd) and the extraction yield, although there was a significant inverse relation (P < 0.05) for two of the proteins, Cry1Ac and Cry2A. The proteins differ in both their affinity for soil and their extraction yields. We conclude that these insecticidal proteins will be largely immobile in soil, but that routine environmental monitoring can give only semi‐quantitative values for protein in soil.

During the recent decade, uncultured bacteria have been special interest as potential candidates for discovering novel antibacterial compounds. Two strains C101 and C102 were negative Gram bacteria, only growing on low nutrient media as R2A/3, NB/3, LB/10 and R4/10 compared to the usual. On R2A/3 medium, colonies of the isolates were round, convex, lemon yellow color with the size of 1-1.5 mm after six days of incubation at 28oC. Cells were 0.2-0.3 × 0.8-1.3 µm. The strains C101 and C102 were able to grow at temperature ranging 15-37oC (optimum at 25-28oC), pH 5-8 (optimum in pH 6-7). The sequences of 16S rRNA genes from strain C101 (MT756087) and C102 (MT756088) shared 100% identity. Analysis of full-length 16S rRNA gene sequence of strain C101 via using NCBI Blast, EzTaxon Database revealed the highest similarity of 99.18-100% to uncultured clones, and 97.86% to type species as Parasegetibacter terrae SGM2-10T. Genetic sequence analysis data showed that strain C101 should be considered a novel candidate species of the genus Parasegetibacter. Antibacterial compound was extracted from culture of strain C101 in R4/10 medium for ten days of shaking incubator at 28oC and exhibited susceptible activity to inhibit Bacillus anthracis KEMB 211-146 at a concentration of 2 µg/L and Staphylococcus aureus ATCC 6538 at 4 µg/L; intermediate inhibiting Bacillus subtilis KEMB 51201-001 at 8 µg/L, Staphylococcus epidermidis ATCC 14990 at 8 µg/L, and S. aureus CCARM 3155 at 16 µg/L; inhibition of S. aureus CCARM 3095 at 64 µg/L, S. aureus CCARM 3192 at 32 µg/L, and S. epidermidis CCARM 3710 at 64 µg/L.