Host specificity,pathogenicity and the presence of virulence genes in Iranian strains of Pseudomonas syringae pv. syringae from different hosts

Pseudomonas syringae pv. syringae (Pss) strains were isolated from almond, apricot, peach, pear, sweet cheery and wheat in Kohgiluye and Boyer-Ahmad, Kordestan, Fras and Chaharmahal and Bakhtiari provinces of Iran. The strains were examined for host specificity, the presence of virulence genes and pathogenicity on different hosts. After inoculation of isolates, in compatible reactions bacterial populations increased within six days of inoculation and final cell numbers increased several-fold over initial inoculum levels, but in incompatible reactions, bacterial populations declined within four days of inoculation. Almond, sweet cherry and wheat isolates induced progressive necrotic symptoms on almond leaves and stems. Apricot, peach and sweet cherry isolates induced necrotic lesions when inoculated on apricot leaves. On pear leaves and stems, only the pear isolate incited pathogenic reaction and isolates from other hosts did not. The syrB gene was detected in all of the tested isolates. Almond and pear isolates did not have the syrD gene. The sypA gene was detected in the almond, peach, pear and sweet cherry isolates while the sypB gene was detected in the apricot, peach, sweet cherry and wheat isolates. Almond, apricot, pear and wheat isolates gave negative results for the detection of nit gene. The gene Ach, was detected only in the peach isolate and gene hrmA, was detected only in the wheat isolate. This study indicates that host specificity exists among different Pss strains, and genes responsible for syringomycin and syringopeptin production contribute to the virulence of Pss strains.     

High-frequency fire alters soil and plant chemistry but does not lead to nitrogen-limited growth of <Emphasis Type="Italic">Eucalyptus pilularis</Emphasis> seedlings

Background and aims

The current study was undertaken to investigate the mechanism underlying Boron (B)-alleviated phosphate (P) deficiency in Arabidopsis thaliana. Furthermore, we were interested to explore whether this alleviation of P deficiency by B could extend to Brassica crops.

Methods

Arabidopsis thaliana or Brassica oleracea plants were grown under P-sufficient or -deficient condition with or without extra B for 7 days, then shoots and roots of B. oleracea were sampled for analysis of soluble P content while those of A. thaliana were harvested for analysis of total P content, soluble P content and nitric oxide (NO) as well as for cell wall extraction and RNA isolation.

Results

A. thaliana plants showed reduced root growth and decreased P content in the root under P-deficient conditions, but improved root growth when supplemented with additional B. Further analysis revealed that exogenous B elevated the cell wall pectin content and facilitated the release of P in P-deficient seedlings, thus more soluble P was available to sustain growth under P deficiency. Furthermore, B supplement also increased soluble P in P-deficient cabbage (Brassica oleracea var. capitata L.), an economically important vegetable crop. P deficiency alone was sufficient to induce NO accumulation, and in combination with B application further enhanced NO accumulation, while exogenous application of NO scavenger c-PTIO [2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide] counteracted this positive effect of B, indicating that NO is positively involved in B-mediated alleviation of P deficiency.

Conclusions

Our study reveals the critical role of B in improving the growth of P-deficient plants, and also provides evidence implicating the involvement of NO signal.

     

Population Genetic Structure of Transcaucasian Mole Vole (<Emphasis Type="Italic">Ellobius lutescens</Emphasis>) Along Zagros Mountains,Iran

The Zagros and Alborz mountainous ridges can be regarded as one of the most interesting and known physical barriers responsible for the vicariance event. Based on the probable effect of Zagros Mountains on the rodent population vicariance, a research on Caucasian mole vole phylogeography, population genetic structure and diversity was designed along the mentioned mountainous areas. To this end, a total of 38 tissue samples were collected from the northern parts of the study area to the southern parts. Obtained mitochondrial cytb (1041 bp) sequences were used in this phylogenetic analysis. The phylogenetic analysis was based on the TRN+I evolutionary model and gaining Bayesian phylogenetic tree with maximum verification. By using median joining logic, the relationships between different acquired haplotypes were analyzed. It was shown that the Caucasian mole vole population had been disjointed (based on posterior probability of 1 and 100 bootstraps) along the Zagros mountainous ridges, especially in both geographical extremes located in the northern and southern parts of the mountainous ridges. Meanwhile from the 38 analyzed sequences, 17 haplotypes were obtained, of which 10 haplotypes were unique. The mutational steps between haplotypes were assessed by generating statistical parsimony haplotype networks, which yielded 36 mutational steps between the northern and southern populations. Based on neutrality tests and analyzing their power under sudden population expansions, it was found that this event happened around the northern and southern populations. Genetic distance of two percent between the northern and southern populations indicated the existence of local adaptations by these two groups, which can be regarded as evolutionary units.     

Development of a novel engineered antibody targeting human CD123

Antibody engineering involves a range of custom modifications of immunoglobulins to improve their affinity, valency, and pharmacokinetics, ensuring a better target therapy achievement. A number of therapeutic antibodies have been used for cell surface receptor blockage, interfering with the ligand binding and inhibiting receptor-driven activation of cells. Here we describe the construction and characterization of a recombinant bivalent single-chain Fv (biscFv) that targets CD123. On conversion of anti-CD123 scFv to biscFv format, the recognition of the cognate ligand is not altered. Moreover, the increased overall efficacy of the anti-CD123 biscFv in binding and inhibition of CD123/IL-3 (interleukin-3) interactions in TF-1 cells is demonstrated.     

Nest-site selection and its impact on breeding success of the Lesser Kestrel,Falco naumanni,in the North of Iran (Aves: Falconiformes)

The Lesser Kestrel (Falco naumanni) is a small migratory falcon which nests coloni- ally on inland cliffs and ruined buildings. Bandar Turkman city holds one of the most important breeding colonies in Iran. It nests in holes in roofs, walls or on ledges of buildings throughout of the city. We tried to find out whether there is a relationship between nest-site selection and breeding success. Although height from the ground is the most important factor in nest-site selection by F. naumanni, height from the floor and distance to the nearest neighbour are other main factors which affect breeding success. This could be the result of accessibility by human and natural predators such as domestic cats which threaten nests. The number of possible nest-sites in the study area is limited as many old, ruined buildings are being replaced by new construc- tions; this colonially breeding bird species therefore suffers from a lack of highly suitable nest-sites and this directly affect breeding success.     

Tissue composition effect on dose distribution in neutron brachytherapy/neutron capture therapy

Aim

The aim of this study is to assess the effect of the compositions of various soft tissues and tissue-equivalent materials on dose distribution in neutron brachytherapy/neutron capture therapy.

Background

Neutron brachytherapy and neutron capture therapy are two common radiotherapy modalities.

Materials and methods

Dose distributions were calculated around a low dose rate ²⁵²Cf source located in a spherical phantom with radius of 20.0 cm using the MCNPX code for seven soft tissues and three tissue-equivalent materials. Relative total dose rate, relative neutron dose rate, total dose rate, and neutron dose rate were calculated for each material. These values were determined at various radial distances ranging from 0.3 to 15.0 cm from the source.

Results

Among the soft tissues and tissue-equivalent materials studied, adipose tissue and plexiglass demonstrated the greatest differences for total dose rate compared to 9-component soft tissue. The difference in dose rate with respect to 9-component soft tissue varied with compositions of the materials and the radial distance from the source. Furthermore, the total dose rate in water was different from that in 9-component soft tissue.

Conclusion

Taking the same composition for various soft tissues and tissue-equivalent media can lead to error in treatment planning in neutron brachytherapy/neutron capture therapy. Since the International Commission on Radiation Units and Measurements (ICRU) recommends that the total dosimetric uncertainty in dose delivery in radiotherapy should be within ±5%, the compositions of various soft tissues and tissue-equivalent materials should be considered in dose calculation and treatment planning in neutron brachytherapy/neutron capture therapy.     

Computational biomechanics of human brain with and without the inclusion of the body under different blast orientation

Three different human head models in a free space are exposed to blast waves coming from four different directions. The four head–neck–body models composed of model a, with the neck free in space; model b, with neck fixed at the bottom; and model c, with the neck attached to the body. The results show that the effect of the body can be ignored for the first milliseconds of the head–blast wave interactions. Also one can see that although most biomechanical responses of the brain have similar patterns in all models, the shear stresses are heavily increased after a few milliseconds in model b in which the head motion is obstructed by the fixed-neck boundary conditions. The free-floating head model results are closer to the attached-body model.