Regulation of crystal protein biosynthesis by Bacillus thuringiensis: I. Effects of mineral elements and pH

Özcengiz, Gülay
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 omission of Zn and Ca had no effect on toxin formation. Crystal protein synthesis and sporulation did not generally seem to be co-regulated by the minerals as these processes responded differently to mineral levels. There was no evidence for suppression of biosynthesis by inorganic phosphate over a range of 3 to 100 mM. Crystal protein production was more efficient in buffered medium, especially when the initial pH was adjusted to 6.5. (C) 2002 Editions scientifiques et medicales Elsevier SAS. All rights reserved.


Regulation of crystal protein biosynthesis by Bacillus thuringiensis: II. Effects of carbon and nitrogen sources.
Içgen, Y; İçgen, Bülent; Özcengiz, Gülay (Elsevier BV, 2002-11-01)
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 organi...
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...
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...
BASALP, A; Özcengiz, Gülay; ALAEDDINOGLU, NG (Springer Science and Business Media LLC, 1992-03-01)
Bacilysin biosynthesis and alkaline serine protease production in Bacillus subtilis 168 were monitored and compared in batch cultures when various effectors of sporulation were added at different stages of growth in a medium containing sucrose and glutamate. Depending on the time of addition, glucose affected sporulation and serine protease formation to the same extent, but had no effect on bacilysin production. Ammonium and L-alanine additions suppressed all three processes. Casamino acids severely interfe...
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. ...
Citation Formats
Y. ICGEN, B. Icgen, and G. Özcengiz, “Regulation of crystal protein biosynthesis by Bacillus thuringiensis: I. Effects of mineral elements and pH,” RESEARCH IN MICROBIOLOGY, pp. 599–604, 2002, Accessed: 00, 2020. [Online]. Available: