Regulation of crystal protein biosynthesis by Bacillus thuringiensis: II. Effects of carbon and nitrogen sources.

The regulation of crystal protein production in Bacillus thuringiensis 81 by sources of carbon and nitrogen was investigated. The highest titers of toxin were obtained on sucrose, lactose and inulin which also supported sporulation. Whey and molasses were also potential carbon substrates for toxin production. Other carbohydrates including glucose, glycerol, maltose, starch and dextrin yielded lower amounts of toxin. Nitrogen sources were found to exert the most profound controls. Peptone was the best organic nitrogen source, supporting optimum production and sporulation as well as high cell density. The formation of CryI and CryII toxin proteins was found to be differentially regulated by the inorganic nitrogenous compounds incorporated into the medium. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.
Research in microbiology


Regulation of crystal protein biosynthesis by Bacillus thuringiensis: I. Effects of mineral elements and pH
ICGEN, Y; Icgen, BÜLENT; Özcengiz, Gülay (Elsevier BV, 2002-11-01)
Crystal protein synthesis by a local isolate of Bacillus thuringiensis was monitored and compared in association with growth and sporulation in media differing in mineral element content. Mg and Cu were the most important metals for the biosynthesis of 135 kDa and 65 kDa toxin components in that the former was essential and the latter was greatly stimulatory at 10(-6) to 10(-7) M concentration. Also the inclusion of Mn favored toxin production at concentrations ranging from 3 x 10(-4) to 10(-5) M. The omiss...
Exposure to sulfide causes populations shifts in sulfate-reducing consortia
İçgen, Bülent (Elsevier BV, 2006-10-01)
The shift in the community structure of a mixed culture of sulfate-reducing bacteria (SRB) at 0.5, 0.75, 1, and 1.5 kg m(-3) sulfide loadings was investigated in an anaerobic continuous bioreactor used for treatment of sulfate-containing wastewater by fluorescence in situ hybridization (FISH), using SRB species-specific and group-specific 16S rRNA-targeting probes. Hybridization analysis using these 16S rRNA-targeted oligonucleotide probes revealed that sulfide was toxic for Desulfonema, Desulfobulbus spp. ...
Nutritional and cultural parameters influencing antidipteran delta endotoxin production
ÖZKAN, MELEK; Dilek, Filiz Bengü; Yetiş, Ülkü; Özcengiz, Gülay (Elsevier BV, 2003-01-01)
In this study, various nutritional and cultural parameters influencing diptera-specific delta-endotoxin synthesis by Bacillus thuringiensis subsp. israelensis HD500 were investigated. Of various inorganic nitrogen sources, the highest yields of Cry11Aa and Cry4Ba proteins were obtained on (NH4)(2)HPO4. Among carbon sources, inulin, dextrin, maltose, lactose, sucrose, whey and glycerol were all stimulatory, while glucose, starch and molasses were suppressive. High concentrations of inorganic phosphate (50 to...
Identification of population dynamics in sulfate-reducing consortia on exposure to sulfate
İçgen, Bülent (Elsevier BV, 2006-12-01)
The microbial population structure and function of a mixed culture of sulfate-reducing bacteria (SRB) maintained in anaerobic continuous bioreactors were tracked before and after a major perturbation, which involved the addition of sulfate to the influent of a bioreactor when operated at steady state at 35 degrees C, pH 7.8 and a 2.5 day residence time with feed stream containing 10 and 15 kg m(-3) sulfate as terminal electron acceptor and 19.6 and 29.4 kg m(-3) 4 ethanol as carbon source and electron donor...
Cloning, characterization and heterologous expression of the aspartokinase and aspartate semialdehyde dehydrogenase genes of cephamycin C-producer Streptomyces clavuligerus
Tunca, S; Yilmaz, EI; Piret, J; Liras, P; Özcengiz, Gülay (Elsevier BV, 2004-09-01)
Carbon flow through the lysine branch of the aspartate biosynthetic pathway is a rate-limiting step in the formation of cephamycin C, a broad spectrum P-lactam antibiotic produced by Streptomyces clavuligerus. In this study, genes which encode the enzymes catalyzing the first two steps of the aspartate pathway, ask (aspartokinase) and asd (aspartate semialdehyde dehydrogenase), in S. clavuligerus NRRL 3585 were cloned and sequenced. Nucleotide sequencing and codon preference analysis revealed three complete...
Citation Formats
Y. Içgen, B. İçgen, and G. Özcengiz, “Regulation of crystal protein biosynthesis by Bacillus thuringiensis: II. Effects of carbon and nitrogen sources.,” Research in microbiology, pp. 605–9, 2002, Accessed: 00, 2020. [Online]. Available: