NF-kB related transgene expression in mouse tibial cranial muscle after pDNA injection followed or not by electrotransfer.

BACKGROUND: When activated, NF-κB can promote the nuclear import and transcription of DNA possessing NF-κB consensus sequences. Here, we investigated whether NF-κB is involved in the plasmid electrotransfer process. METHODS: Mouse tibial cranial muscles were transfected with plasmids encoding luciferase bearing or not NF-κB consensus sequences. Luciferase transgene expression was evaluated noninvasively by luminescence imaging and the number of pDNA copies in the same muscles by qPCR. RT-PCR of heat shock protein HsP70 mRNA evidenced cell stress. Western blots of phosphorylated IkBα were studied as a marker of NF-κB activation. RESULTS: Intra-muscular injection of a plasmid bearing a weak TATA-like promoter results in a very low muscle transfection level. Electrotransfer significantly increased both the number of pDNA copy and the transgene expression of this plasmid per DNA copy. Insertion of NF-κB consensus sequences into pDNA significantly increased the level of gene expression both with and without electrotransfer. Electrotransfer-induced cellular stress was evidenced by increased HsP70 mRNA. Phosphorylated IκBα was slightly increased by simple pDNA injection and a little more by electrotransfer. We also observed a basal level of phosphorylated IκBα and thus of free NF-κB in the absence of any stimulation. GENERAL SIGNIFICANCE: pDNA electrotransfer can increase transgene expression independently of NF-κB. The insertion of NF-κB consensus sequences into pDNA bearing a weak TATA-like promoter leads to enhanced transgene expression in muscle with or without gene electrotransfer. Finally, our results suggest that the basal amount of free NF-κB in muscle might be sufficient to enhance the activity of pDNA bearing NF-κB consensus sequences.

Antibacterial triterpenes from Syzygium guineense (Myrtaceae).

Antibacterial bioassay-guided fractionation of Syzygium guineense leaf extracts afforded 10 triterpenes, namely betulinic acid 1, oleanolic acid 2, a mixture of 2-hydroxyoleanolic acid 3a, 2-hydroxyursolic acid 3b, arjunolic acid 4a, asiatic acid 4b, a mixture of terminolic acid 5a, 6-hydroxyasiatic acid 5b, and a mixture of arjunolic acid 28-beta-glucopyranosyl ester 6a and the asiatic acid 28-beta-glucopyranosyl ester 6b. Isolated compounds were submitted to an antibacterial assay system against gram-positive and -negative bacteria and human pathogen bacteria. Compounds 4a and 4b showed the most significant antibacterial activity against Escherichia coli, Bacillus subtilis and Shigella sonnei. The fraction 5a-5b was the least active, whereas compounds 1, 2 and the mixtures of 3a-3b and 6a-6b were inactive in the assays.

Effect of essential oils from leaves of Ageratum conyzoides, Lantana camara and Chromolaena odorata on the mortality of Sitophilus zeamais (Coleoptera, Curculionidae).

Ageratum conyzoides, Chromolaena odorata, and Lantana camara, are common weed species in Cameroon. Essential oil extracts from their leaves were tested for efficacy on the morality of the maize grain weevil, Sitophilus zeamais (Coleoptera, Curculionidae). Concentrations of the essential oils relative to the maize grains of 0.013, 0.025, 0.05 and 0.1% (v/w) were used for A. conyzoides and 0.063, 0.125, 0.25 and 0.50% (v/w) for C. odorata and L. camara. Twenty 7-day old adult weevils were fed on maize grains treated with the above concentrations of the essential oils in Petri dishes. Control dishes contained insects and maize grains without essential oils. The experiment was repeated three times. Dishes were incubated in the laboratory for 7 days at 26 degrees C and 75-85% relative humidity. Insect mortality was recorded every 24 h. Graphs of percentage mortality versus the duration of exposure were constructed and the LD(50) was computed for each oil. Significant insect mortality was obtained with all the essential oils used. The mortality of S. zeamais increased with the concentration of the essential oils of the three plants and the duration of exposure of the weevils on the treated substrates. The essential oil extract of Ageratum conyzoides was the most effective insecticide (LD(50)=0.09% in 24 h), followed by that of L. camara (LD(50)=0.16%) and C. odorata (LD(50)=6.78%). These results show that the essential oils of the leaves of some of these weed species may be exploited for insect control in stored products.