The Impact of Inoculation of Two Strains of Rhizobacteria on Radionuclide Transfer in Sesbania Grandiflora.

Transfer factors of some naturally-occurring and artificial radionuclides from an agricultural soil to rhizobacteria-treated Sesbania grandiflora, a small leguminous tree, were studied. Two plant growth promoting rhizobacteria (PGPR) strains (SCR17 and PCE2) were used to carry out an agricultural experiment in pots in semi-arid region (Syria). The results showed the bacterial strain (SCR17) increased the transfer and accumulation of 238U and 40K in Sesbania grandiflora, while both bacterial strains showed no effect on the accumulation of 234Th, 226Ra, 210Po and 210Pb in the treated plants. The transfer factor of 137Cs from soil to rhizobacteria-treated Sesbania grandiflora was negligible. The values of the transfer factors of 234Th, 226Ra, 210Po and 40K were found to be within the global values, while the values of the transfer factors of 238U and 210Pb were found to be relatively higher. This study highlights the importance of using Phytoremediation by PGPR strains for radionuclides-contaminated soils. Therefore, this method is a promising technique for the restoration and rehabilitation of contaminated sites with radionuclides, as it is low cost, easy to apply, and environmentally friendly.

Chaperonin GroEL a Brucella immunodominant antigen identified using Nanobody and MALDI-TOF-MS technologies.

The deployment of today's antibodies that are able to distinguish Brucella from the closely similar pathogens, such as Yersinia, is still considered a great challenge since both pathogens share identical LPS (lipopolysaccharide) O-ring epitopes. In addition, because of the great impact of Brucella on health and economy in many countries including Syria, much effort is going to the development of next generation vaccines, mainly on the identification of new immunogenic proteins of this pathogen. In this context, Brucella-specific nanobodies (Nbs), camel genetic engineered heavy-chain antibody fragments, could be of great value. Previously, a large Nb library was constructed from a camel immunized with heat-killed Brucella. Phage display panning of this 'immune' library with Brucella total lysate resulted in a remarkable fast enrichment for a Nb referred to as NbBruc02. In the present work, we investigated the main characteristics of this Nb that can efficiently distinguish under well-defined conditions the Brucella from other bacteria including Yersinia. NbBruc02 showed a strong and specific interaction with its antigen within the crude lysate as tested by a surface plasmon resonance (SPR) biosensor and it was also able to pull down its cognate antigen from such lysate by immuno-capturing. Using matrix assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF-MS), NbBruc02 specific antigen was identified as chaperonin GroEL, also known as heat shock protein of 60 kDa (HSP-60), which represents a Brucella immunodominant antigen responsible of maintaining proteins folding during stress conditions. Interestingly, the antigen recognition by NbBruc02 was found to be affected by the state of GroEL folding. Thus, the Nb technology applied in the field of infectious diseases, e.g. brucellosis, yields two outcomes: (1) it generates specific binders that can be used for diagnosis, and perhaps treatment, and (2) it identifies the immunogenic candidate antigens for developing vaccines.

Transcriptional interactions during barley susceptible genotype infection with Cochliobolus sativus.

A systematic sequencing of expressed sequence tags (ESTs) was used to obtain a global picture of the assembly of barley genes differentially expressed during the hypersensitive reaction of a susceptible genotype in response to an incompatible Cochliobolus sativus pathovar. To identify a large number of plant ESTs, which are induced at different time points, an amplified fragment length polymorphism (AFLP) display of complementary DNA (cDNA) was ulilized. Significant transcriptional changes in the host plant occurred already 4 h post inoculation. Four hundred and fifty six ESTs have been generated, of which 17 (c. 53% up-regulated, 47% down-regulated) have no previously described function. On one hand, the majority of EST-annotations showed protein synthesis, but genes related to signal transduction pathway were also identified. This study provides novel global catalogue ofgene regulations involved in C. sativus-barley interaction not currently represented in EST databases.