Hybridization of wheat and Aegilops cylindrica: development,karyomorphology, DNA barcoding and salt tolerance of the amphidiploids

The development of salt‐tolerant genotypes is key to a better utilization of salinized irrigated lands. Given the relatively low genetic diversity within the cultivated wheats for salt tolerance, exploring the Aegilops cylindrica's genetic diversity for salt tolerance is thus crucial to breed wheat for saline environments. In the current study, wheat genotypes were hybridized with Ae. cylindrica (a hyper salt-tolerant genotype), and amphidiploid plants were produced using embryo rescue and chromosome doubling techniques. Crossability and cytological examinations of amphidiploids and BC₁ were performed before sequencing the ITS4/5 and trnE/trnF DNAs to explore the phylogenetic relationships of the amphidiploids and their parents. Finally, amphidiploids were assessed for salt tolerance. Only two common wheat cultivars (‘Chinese Spring’ and ‘Roshan’) were crossable with Ae. cylindrica. The resultant intergeneric hybrids possessed 70 chromosomes, and morphologically either were similar to the male parent in ‘Chinese Spring’ × Ae. cylindrica or tended to be intermediate between parents in ‘Roshan’ × Ae. cylindrica. The phylogenetic tree divided the genotypes into two groups, in which Clade I contained Ae. cylindrica and three amphidiploids, and Clade II consisted of female parents and one amphidiploid. Amphidiploids exhibited significantly higher tolerance to salt stress compared to the female parents (wheat cultivars) in terms of a higher dry matter, lower accumulation of Na, higher K, and higher K/Na ratio in their root and leaf tissues. Taken together, the amphiploid plants might contain valuable salt tolerance factors.

     

Effect of biotic and abiotic elicitors on production of betulin and betulinic acid in the hairy root culture of Betula pendula Roth

Abstract

Betulin (B) and betulinic acid (BA) are two triterpenoids with a wide range of biological and medicinal activities in different organs of Betula pendula. This research aimed to increase the accumulation of B and BA in the hairy root culture of B. pendula by seven biotic and abiotic elicitors. Hairy root was induced in the stem’s inner bark of B. pendula using the C58C1 strain in the WPM (Woody Plant Medium). The effects of different concentrations of elicitors and different time of root harvest in hairy root culture of B. pendula showed that highest level of growth index (GI), B, and BA was acquired in treated hairy roots with chitosan (CTS), chlorocholine chloride (CCC) and chitosan nano-fiber (CTS NF). Highest GI of B. pendula hairy roots was 13 that was obtained in the roots treated with CTS 150?mg l^?1 on the 8th day. The highest content of BA was 1.3?mg g^?1 DW after treatment with 1?mg l^?1CCC on the 4th and 6th days and 200?mg l^?1CTS NF on the 10th day. The highest B content (0.94?mg g^?1DW) was obtained in the treated hairy root by 2?mg l^?1 CCC after 4 and 6?days.     

Immobilization of HIV-1 TAT peptide on gold nanoparticles: A feasible approach for siRNA delivery

RNA interference is one of the prosperous approaches for cancer treatment. However, small interfering RNA (siRNA) delivery to cancer cells has been faced with various challenges restricting their clinical application over the decades. Since ROR1 is an onco-embryonic gene overexpressed in many malignancies, suppression of ROR1 by siRNA can potentially fight cancer. Herein, a delivery system for ROR1 siRNA based on HIV-1 TAT peptide-capped gold nanoparticles (GNPs) was developed to treat breast cancer. Besides, we introduced a new feasible method for conjugating the peptide to the nanoparticles. Since the GNPs have high affinity to the sulfur, the findings demonstrated the peptide successfully conjugated to the nanoparticles via Au–S bonds. As positively charged nanoparticles showed high cellular uptake, we could use a low concentration of nanoparticles led to high efficient gene transfection with negligible cytotoxicity that was confirmed by flow cytometry, confocal microscopy, gel retardation, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Following transfection, downregulation of ROR1 and its targeted gene, CCND1, induced apoptosis in cancer cells. In conclusion, the reported capped GNPs could be potentially utilized for delivering negatively charged therapeutic agents in particular genes.     

Exploiting Edge Effect to Control Generation Rate and Breakdown Voltage in Graphene Nanoribbon Field Effect Transistors

Plasmonics - Based on the influence of edge effect and channel shape, two new graphene nanoribbon field effect transistors are presented being useful in high-voltage and highly sensitive optical...     

Phenotypic and genotypic variation in methylases involved in type II restriction-modification systems in Helicobacter pylori

To determine relationships between Helicobacter pylori geographical origin and type II methylase activity, we examined 122 strains from various locations around the world for methylase expression. Most geographic regions possessed at least one strain resistant to digestion by each of 14 restriction endonucleases studied. Across all of the strains studied, the average number of active methylases was 8.2 ± 1.9 with no significant variation between the major geographic regions. Although seven pairs of isolates showed the same susceptibility patterns, their cagA/vacA status differed, and the remaining 108 strains each possessed unique patterns of susceptibility. From a single clonal group, 15 of 18 strains showed identical patterns of resistance, but diverged with respect to M.MboII activity. All of the methylases studied were present in all major human population groupings, suggesting that their horizontal acquisition pre-dated the separation of these populations. For the hpyV and hpyAIV restriction-modification systems, an in-depth analysis of genotype, indicating extensive diversity of cassette size and chromosomal locations regardless of the susceptibility phenotype, points toward substantial strain-specific selection involving these loci.     

Tipping the balance between replicative and simple transposition

The bacterial insertion sequence IS903 has the unusual ability to transpose both replicatively and non-replicatively. The majority of products are simple insertions, while co-integrates, the product of replicative transposition, occur at a low frequency (<0.1% of simple insertions). In order to define the critical steps that determine the outcome of IS903 transposition, we have isolated mutants that specifically increase the rate of replicative transposition. Here we show that the nucleotide immediately flanking the transposon influences both overall transposition frequency and co-integrate formation. In particular, when the 3'-flanking nucleotide is A, co-integrates are increased 500-fold compared with a 3' C. In addition, we have isolated five transposase mutants that increase replicative transposition. These residues are close to the catalytic residues and are thus likely to be part of the active site. These are the first transposase mutations described that affect the product of transposition. Our results are consistent with the hypothesis that a delay in cleavage of the 5'-flanking DNA will increase the effective half-life of the 3'-nicked transposon intermediate and consequently enhance co-integrate formation.