Synthesis of GnRH analogues and their application in targeted gene delivery systems

A set of GnRH analogues containing the nuclear localization signal (NLS) of the SV-40 virus was synthesized using solid phase peptide synthesis and chemical ligation techniques. Selective chemical ligation was achieved through hydrazone formation upon the interaction of NLS hydrazide and GnRH analogue modified with pyruvic acid. The efficiency of the synthesized compounds was demonstrated in experiments on transfection of various human cancer cell lines with reporter luciferase and β-galactosidase genes, as well as suicide thymidine kinase gene of HSV-1. Selectivity of the peptide-DNA complex effect on cancer cells is achieved as a result of its penetration through the cell membrane via GnRH receptor-mediated endocytosis pathway.     

Genetic dissection of Al tolerance QTLs in the maize genome by high density SNP scan

Background

Aluminum (Al) toxicity is an important limitation to food security in tropical and subtropical regions. High Al saturation on acid soils limits root development, reducing water and nutrient uptake. In addition to naturally occurring acid soils, agricultural practices may decrease soil pH, leading to yield losses due to Al toxicity. Elucidating the genetic and molecular mechanisms underlying maize Al tolerance is expected to accelerate the development of Al-tolerant cultivars.

Results

Five genomic regions were significantly associated with Al tolerance, using 54,455 SNP markers in a recombinant inbred line population derived from Cateto Al237. Candidate genes co-localized with Al tolerance QTLs were further investigated. Near-isogenic lines (NILs) developed for ZmMATE2 were as Al-sensitive as the recurrent line, indicating that this candidate gene was not responsible for the Al tolerance QTL on chromosome 5, qALT5. However, ZmNrat1, a maize homolog to OsNrat1, which encodes an Al³⁺ specific transporter previously implicated in rice Al tolerance, was mapped at ~40 Mbp from qALT5. We demonstrate for the first time that ZmNrat1 is preferentially expressed in maize root tips and is up-regulated by Al, similarly to OsNrat1 in rice, suggesting a role of this gene in maize Al tolerance. The strongest-effect QTL was mapped on chromosome 6 (qALT6), within a 0.5 Mbp region where three copies of the Al tolerance gene, ZmMATE1, were found in tandem configuration. qALT6 was shown to increase Al tolerance in maize; the qALT6-NILs carrying three copies of ZmMATE1 exhibited a two-fold increase in Al tolerance, and higher expression of ZmMATE1 compared to the Al sensitive recurrent parent. Interestingly, a new source of Al tolerance via ZmMATE1 was identified in a Brazilian elite line that showed high expression of ZmMATE1 but carries a single copy of ZmMATE1.

Conclusions

High ZmMATE1 expression, controlled either by three copies of the target gene or by an unknown molecular mechanism, is responsible for Al tolerance mediated by qALT6. As Al tolerant alleles at qALT6 are rare in maize, marker-assisted introgression of this QTL is an important strategy to improve maize adaptation to acid soils worldwide.

Electronic supplementary material

The online version of this article (doi:10.1186/1471-2164-15-153) contains supplementary material, which is available to authorized users.     

The role of bitoxibacillin components in the manifestation of its biological activity

New methods were developed and applied to quantitative determination of beta-exotoxin and antibiotic activity of delta-endotoxin with respect to Micrococcus spp. in bitoxibacillin (BTB) and the fermentation broths prepared under industrial conditions. The biosynthesis of beta-exotoxin in the period of its maximum accumulation during the fermentation was estimated. It was shown that the primary biological effect of BTB on insects consisted in the actions of beta-exotoxin and delta-endotoxin. Biological activity of each of the entomocidal components of the entomocidal components of BTB did not practically correlated with the number of viable spores. There was a correlation between the antibiotic activity of crystalline B. thuringiensis subsp. thuringiensis solutions and the insecticidal activity of the entomopathogenic preparations. Determination of beta-exotoxin and antibiotic activity of delta-endotoxin might be used as a complex procedure for testing the quality of BTB. The method for estimating antibiotic activity of the crystal solutions allowed one to assay the biological activity of other preparations based on Bacillus thuringiensis non-synthesizing beta-exotoxin.     

The effect of the size of the irradiation field on the severity and outcome of the radiation injury of swine skin

Swine skin areas of 12.56 cm2, 50 cm2 and 100 cm2 were exposed to beta-particles from 90Sr + 90Y (100 Gy). The increase in size of the exposed site caused a considerable increase in the degree of the affection and a change in the regeneration rate. Epithelialization of 12.56 cm2 skin field was completed by the 14th-16th week, and it was absent after 4.5 years in the fields of 50 and 100 cm2.     

Influence of thyroliberin and its analogs with different hormonal activity on the pharmacological effects of ethanol

TRH and its two analogs with modified hormonal activity were examined for the capacity to antagonize acute and chronic effects of ethanol in mice. It has been demonstrated that L-pyroglutamyl-L-seryl-L-leucinamide, an analog of TRH, that does not affect the secretion of TSH and decreases prolactin production has the same capacity as TRH to reduce the time of ethanol narcosis but produces a lesser effect on the ethanol-induced fall of rectal temperature. Both the drugs did not affect the ethanol-altered ability of mice to hold on the rotating bar. Methyl ether of TRH, a hormonally inactive analog, was ineffective as shown by all the tests. Neither TRH nor its analogs changed the development of tolerance to chronic administration of ethanol, recorded by the rotating bar test and rectal temperature drop.