background: excessive use of antibiotic growth promoters leaded in the creation of antibiotic-resistant bacteria and by consuming animal products, humans are at risk of receiving their residual. therefore, instead of using antibiotics as growth promoters, some alternatives must be identified and introduced to animal breeders. objectives: the purpose of this research was to study the effect of a...

this experiment was conducted to investigate the effects of using protexin, propionic acid growth promoters, and a blend of them on broilers performance. in a completely randomized design, three hundreds and twenty unsexed 1-d-old chicks were divided into four groups. dietary treatments were consisted of 1) control diet without any supplement, 2) the control diet + 0.01 % protexin, 3) the contr...

We studied the effects of carbon starvation and of varying the growth rate on the activity of each of the two tandem ribosomal RNA promoters from the rrnA operon of Escherichia coli. The cellular abundance of plasmid-encoded transcripts arising at promoters P1 and P2 and terminating at the ribosomal RNA terminator in promoter-terminator fusions, together with transcript turnover rates, was used...

Bacteria use a variety of mechanisms to direct RNA polymerase to specific promoters in order to activate transcription in response to growth signals or environmental cues. Activation can be due to factors that interact at specific promoters, thereby increasing transcription directed by these promoters. We examine the range of architectures found at activator-dependent promoters and outline the ...