Chemical composition, antimicrobial and antioxidant activities data of three plants from Tunisia region: Erodium glaucophyllum, Erodium hirtum and Erodium guttatum.

In the present work, phytochemical contents (total phenolic content, total flavonoids, and condensed tannins), antioxidant potentials, and antimicrobial activities of three plants in the Mediterranean genus Erodium (Erodium glaucophyllum, Erodium hirtum, and Erodium guttatum) from the Tunisia region were analyzed. The results showed that E. glaucophyllum contained high levels of polyphenols, flavonoids, and tannins. Therefore, E. glaucophyllum possesses high antioxidant activities (2,2-diphenyl-1-picrylhydrazyl and ferric reducing antioxidant power scavenging activities), and high inhibition of linoleic acid oxidation. All three plants exhibited high antimicrobial activities. This study highlights tree plants' importance as dietary sources for natural antioxidants can be used in traditional medicine and the pharmaceutical industry.

Bacillus amyloliquefaciens strain 32a as a source of lipopeptides for biocontrol of Agrobacterium tumefaciens strains.

AIMS: A Bacillus amyloliquefaciens strain, designated 32a, was used to identify new compounds active against Agrobacterium tumefaciens and to evaluate their efficiency to control crown gall on carrot discs. METHODS AND RESULTS: Based on PCR-assays, four gene clusters were shown to direct the synthesis of the cyclic lipopeptides surfactin, iturin A, bacillomycin D and fengycin. Mass spectrometry analysis of culture supernatant led to the identification of these secondary metabolites, except bacillomycin, with heterogeneous mixture of homologues. Antimicrobial assays using lipopeptides-enriched extract showed a strong inhibitory activity against several bacterial and fungal strains, including Ag. tumefaciens. Biological control assays on carrot discs using both 32a spores and extract resulted in significant protection against crown gall disease, similar to that provided by the reference antagonistic strain Agrobacterium rhizogenes K1026. CONCLUSIONS: In contrast to all active compounds against Ag. tumefaciens that are of proteinaceous nature, this work enables for the first time to correlate the strong protective effect of B. amyloliquefaciens strain 32a towards crown gall disease with the production of a mixture of lipopeptides. SIGNIFICANCE AND IMPACT OF THE STUDY: The findings could be useful for growers and nursery men who are particularly interested in the biocontrol of the crown gall disease.

Construction of a new high-copy number shuttle vector of Bacillus thuringiensis.

AIMS: Construction and characterization of a new cloning shuttle vector for gene transfer and expression in Bacillus thuringiensis. METHODS AND RESULTS: A novel short and high-copy number shuttle vector called pHBLBIV, was constructed for gene transfer and expression in Bacillus thuringiensis. A 1.6-kbp replicon of a relatively high-copy number endogenous plasmid of a selected B. thuringiensis strain was ligated to Escherichia coli pUC18 replicon containing the ampicillin and the erythromycin resistance genes used for the selection of respectively E. coli and B. thuringiensis transformants. The constructed vector was shown to have a high copy number compared with the conventional B. thuringiensis vectors, and used successfully for the transfer of vegetative insecticidal protein-encoding gene (vip) in between B. thuringiensis strains. CONCLUSIONS: A new shuttle vector of B. thuringiensis-E. coli named pHBLBIV was constructed. It was characterized by its high copy number, small size and segregational stability. This vector was successfully used for vip gene cloning and transfer in B. thuringiensis. SIGNIFICANCE AND IMPACT OF THE STUDY: A novel shuttle vector has been constructed, which has demonstrated potential for the cloning and expression of genes in B. thuringiensis.

Cloning and study of the expression of a novel cry1Ia-type gene from Bacillus thuringiensis subsp. kurstaki.

AIMS: Cloning and expression of a new cry1Ia-type gene of Bacillus thuringiensis. METHODS AND RESULTS: PCR amplification, using gene cry1I-specific primers revealed the presence of such a gene in the strain BNS3 of Bacillus thuringiensis subsp. kurstaki. The cloning and sequencing from BNS3 of the cry1Ia-type gene, called crybns3-3, showed an open reading frame of 2160-bp, encoding a protein of 719 amino acid residues. Both nucleotide and amino acid sequences similarity analysis revealed that the crybns3-3 is a new cry1Ia-type gene, presenting several differences from the cry1Ia-type genes. The study of the expression of crybns3-3 by Northern blot and RT-PCR showed that it was transcribed. The expression of crybns3-3 under the control of BtI and BtII promoters revealed that Crybns3-3 would co-crystallize with the endogenous delta-endotoxins. CONCLUSIONS: crybns3-3 is a novel cry1Ia gene isolated from B. thuringiensis subsp. kurstaki strain BNS3. SIGNIFICANCE AND IMPACT OF THE STUDY: The characteristics of crybns3-3 indicate that it is a new cry1Ia-type gene. Amino acid residue substitutions presented in Crybns3-3 could be exploited for both toxicity and specificity studies. Crybns3-3 would interact and co-crystallize at least partially with the endogenous delta-endotoxins of BNS3, and then participate in the formation of the parasporal crystal inclusions.