Optimization of regeneration and transformation parameters in tomato and improvement of its salinity and drought tolerance

As part of our efforts to improve tomato tolerance to abiotic stress, we have undertaken this study to introduce two candidate genes encoding: a sodium antiporter and a vacuolar pyrophosphatase, previously shown to enhance drought and salt tolerance in transgenic Arabidopsis plants. First, we evaluated the potential of primary leaves from three to four week-old in vitro-grown tomato seedlings as alternative explants to cotyledons for tomato transformation. Our results demonstrated that primaryleaves are three times more efficient then cotyledons in terms of regeneration percentage, productivity, and transformation frequencies independently of the medium and genetic construct used. Second,primary leaves were used to introduce the genes of interest using Agrobacterium-mediated transformation. Many transgenic tomato plants were easily recovered. The presence of the transgenes and their expression were confirmed by PCR and RT-PCR analysis. The transformation frequencies for primary leaf explants ranged from 4 to 10% depending on the genetic construct used. The time requiredfrom inoculation of primary leaves with Agrobacterium cells to transfer of transgenic tomato plants to soil was only 2 months compared to 3 to 4 months using standard tomato transformation protocols. The transgenic tomato plants obtained in the current study were more tolerant to salinity and drought stress than their wild-type counterparts

Effect of Cd2+ on the Growth and Thermal Properties of K2SO4 crystal

Single crystals of pure and Cd2+ doped potassium sulfate were grown from aqueous solutions by the slow evaporation technique. From nutrient solutions with a CdSO4 concentration of 4wt.% crystals containing 0.014wt.% dopant concentration could be obtained. The X-ray diffraction patterns of powdered crystals confirmed their crystal structures for both cases. Thermal analysis of pure crystals shows that the alpha-beta phase transformation peak around 580 deg C is superimposed with spurious effects, while for Cd2+ doped crystals this is not the case. The thermal hysteresis of the phase transition is 8 K for undoped K2SO4 and is reduced to 3.5 K for K2SO4:Cd2+. Compared to undoped crystals, the optical transmittance of Cd2+ doped crystals is higher.Comment: 5 pages, 6 figure

Is there a common water-activity limit for the three domains of life?

Archaea and Bacteria constitute a majority of life systems on Earth but have long been considered inferior to Eukarya in terms of solute tolerance. Whereas the most halophilic prokaryotes are known for an ability to multiply at saturated NaCl (water activity (a w) 0.755) some xerophilic fungi can germinate, usually at high-sugar concentrations, at values as low as 0.650-0.605 a w. Here, we present evidence that halophilic prokayotes can grow down to water activities of <0.755 for Halanaerobium lacusrosei (0.748), Halobacterium strain 004.1 (0.728), Halobacterium sp. NRC-1 and Halococcus morrhuae (0.717), Haloquadratum walsbyi (0.709), Halococcus salifodinae (0.693), Halobacterium noricense (0.687), Natrinema pallidum (0.681) and haloarchaeal strains GN-2 and GN-5 (0.635 a w). Furthermore, extrapolation of growth curves (prone to giving conservative estimates) indicated theoretical minima down to 0.611 a w for extreme, obligately halophilic Archaea and Bacteria. These were compared with minima for the most solute-tolerant Bacteria in high-sugar (or other non-saline) media (Mycobacterium spp., Tetragenococcus halophilus, Saccharibacter floricola, Staphylococcus aureus and so on) and eukaryotic microbes in saline (Wallemia spp., Basipetospora halophila, Dunaliella spp. and so on) and high-sugar substrates (for example, Xeromyces bisporus, Zygosaccharomyces rouxii, Aspergillus and Eurotium spp.). We also manipulated the balance of chaotropic and kosmotropic stressors for the extreme, xerophilic fungi Aspergillus penicilloides and X. bisporus and, via this approach, their established water-activity limits for mycelial growth (∼0.65) were reduced to 0.640. Furthermore, extrapolations indicated theoretical limits of 0.632 and 0.636 a w for A. penicilloides and X. bisporus, respectively. Collectively, these findings suggest that there is a common water-activity limit that is determined by physicochemical constraints for the three domains of life

Structural properties of phosphate-washing waste based geopolymeric mortars

The phosphate ore extraction activities often generate serious environmental problems, particularly those engendered by the phosphate washing waste. The waste was characterized by X ray fluorescence. The powder was calcined at 700 °C. The calcined and uncalcined samples were then investigated by means of X-ray powder diffraction (XRD). The calcined PWW was activated with sodium hydroxide and sodium silicate to produce geopolymeric materials. The reached results prove to reveal that the present phases in the powder appeared to have a remarkable effect on the result of compressive strength

Evidence of magnetoelectric coupling in 0.9BiFeO 3 -0.1Ba[Ti 0.95 (Yb 0.5 Nb 0.5 ) 0.05 ]O 3 ceramic

International audienceThe physical properties of the Multiferroïc lead-free 0.9BiFeO 3-0.1Ba[Ti 0.95 (Yb 0.5 Nb 0.5) 0.05 ]O 3 ceramic were investigated by in-situ M€ ossbauer spectroscopy, X-ray diffraction (XRD), dielectric measurements and Raman scattering. Both BiFeO 3 and 0.9BiFeO 3-0.1Ba[Ti 0.95 (Yb 0.5 Nb 0.5) 0.05 ]O 3 ceramics underwent in-situ M€ ossbauer spectroscopy in the temperature range of 300 K to 653 K and the parameters of hyperfine interactions were determined. The magnetic transition temperature T N of our doped sample was of 568 K, which was lower than that of BiFeO 3. This reduction of T N originated from the presence of different exchange constants resulting from the weakening of J Fe-Fe. The deviation of the reduced magnetic hyperfine field H(T)/H(0) as a function of the reduced temperature T/T N from the Brillouin curve of Fe 3þ (S ¼ 5/2) for the three sextets and the determination of the critical exponent b, of 0.375 ± 0.022 in the range of 0.01 < 1-T/T N < 0.5 revealed a 3D magnetic long range order phase transition. The complexity of the spatial spin structure was a result of the canting of antiferromagnetically ordered spins of BiFeO 3. Our findings revealed the effect of the non-magnetic substituents Ba and Yb/Nb/Ti in A and B sites, respectively on the magnetic properties. Around the magnetic transition temperature, both isomer shift evolution and quadruple splitting distribution showed pronounced anomalies associated with the onset of magnetic ordering. The Debye temperature (q D) was deduced to be of 257 ± 21 K. These results revealed 0.9BiFeO 3-0.1Ba[Ti 0.95 (Yb 0.5 Nb 0.5) 0.05 ]O 3 as a promising material for piezoelectric devices. XRD analyses were performed for temperatures from 300 K up to 750 K. Gradual structural evolution, as temperature increased, exhibited an isostructural phase transition and an anomaly in the evolution of lattice parameters and the unit cell volume as well as a significant shift in the atomic positions near the magnetic transition temperature T N. These behaviors indicate magnetoelastic coupling. The temperature dependence of the real part of dielectric permittivity and dielectric loss (tan d) was investigated over a wide range of temperatures at 1 kHz. During its evolution, an anomaly was observed at 568 K; which corresponded to the magnetic transition temperature T N. Raman scattering spectra were measured in the temperature range from 303 K to 728 K. Drastic changes, especially that of the three two-phonon modes centered at around 1000-1500 cm À1 , were the results of magnetic rearrangement and atomic displacement leading to both modulating magnetic exchange interaction and polarization state. All these results prove the magnetoelectric coupling of 0.9BiFeO 3-0.1Ba[Ti 0.95 (Yb 0.5 Nb 0.5) 0.05 ]O 3 ceramic