Over-expression of a cDNA for human ornithine decarboxylase in transgenic rice plants alters the polyamine pool in a tissue-specific manner

We investigated how over-expression of a cDNA for human ornithine decarboxylase (odc) affects the polyamine pools in transgenic rice. We further investigated tissue-specific expression patterns and product accumulation levels of the transgene driven by either constitutive or seed-specific promoters. Our results indicate that: (1) whereas the expression of a heterologous arginine decarboxylase (adc) cDNA in rice resulted in increased putrescine and spermine levels only in seeds, plants engineered to express odc cDNA exhibited significant changes in the levels of all three major polyamines in seeds and also in vegetative tissues (leaves and roots); (2) there was no linear correlation between odc mRNA levels, ODC enzyme activity and polyamine accumulation, suggesting that control of the polyamine pathway in plants is more complex than in mammalian systems; (3) ODC activity and polyamine changes varied in different tissues, indicating that the pathway is regulated in a tissue-specific manner. Our results suggest that ODC rather than ADC is responsible for the regulation of putrescine synthesis in plants.     

Novel tetrazole and cyanamide derivatives as inhibitors of cyclooxygenase-2 enzyme: design,synthesis, anti-inflammatory evaluation,ulcerogenic liability and docking study

Nineteen new compounds containing tetrazole and/or cyanamide moiety have been designed and synthesised. Their structures were confirmed using spectroscopic methods and elemental analyses. Anti-inflammatory activity for all the synthesised compounds was evaluated in vivo. The most active compounds 4c, 5a, 5d–f, 8a and b and 9a and b were further investigated for their ulcerogenic liability and analgesic activity. Pyrazoline derivatives 9b and 8b bearing trimethoxyphenyl part and SO₂NH₂ or SO₂Me pharmacophore showed equal or nearly the same ulcerogenic liability (UI: 0.5, 0.75, respectively), to celecoxib (UI: 0.50). Most of tested compounds showed potent central and/or peripheral analgesic activities. Histopathological investigations were done to evaluate test compounds effect on rat's gastric tissue. The obtained results were in consistent with the in vitro data on COX evaluation. Docking study was also done for all the target compounds inside COX-2-active site.     

Augmented simvastatin cytotoxicity using optimized lipid nanocapsules: a potential for breast cancer treatment

Context: We noticed paucity in exploiting solutol-based lipid nanocapsules in statins formulations though they carry all favorable properties that are needed for cancer passive targeting such as their small particle size, stealth properties, ability to highly accommodate lipophilic drugs, good internalization and P-gp pump inhibition.

Objective: The aim of this study was to design and optimize new simvastatin drug delivery systems; lipid nanocapsules intended for administration through the intravenous route as potential treatment for breast cancer.

Methods: Optimized nanocapsules were prepared by the phase-inversion method according to a D-optimal mixture design, characterized and assessed for their cytotoxicity.

Results: Three successful models for particle size, polydispersity index (PDI) and percentage of drug released after 48 h were generated. The prepared lipid nanocapsules acquired spherical and homogenous morphology, good stability and tolerance to sterilization. The obtained release profiles demonstrated desired sustained release pattern. Furthermore, testing selected formulations on human breast cancer adenocarcinoma cells showed augmented cytotoxicity of simvastatin reaching low IC50 values as 1.4?±?0.02 μg/ml compared to the pure drug.

Conclusion: The proposed lipid nanocapsules pose promising candidates as simvastatin carriers intended for the targeting of breast cancer.     

Improved Salinity Tolerance of Rice Through Cell Type-Specific Expression of AtHKT1;1

Previously, cell type-specific expression of AtHKT1;1, a sodium transporter, improved sodium (Na⁺) exclusion and salinity tolerance in Arabidopsis. In the current work, AtHKT1;1, was expressed specifically in the root cortical and epidermal cells of an Arabidopsis GAL4-GFP enhancer trap line. These transgenic plants were found to have significantly improved Na⁺ exclusion under conditions of salinity stress. The feasibility of a similar biotechnological approach in crop plants was explored using a GAL4-GFP enhancer trap rice line to drive expression of AtHKT1;1 specifically in the root cortex. Compared with the background GAL4-GFP line, the rice plants expressing AtHKT1;1 had a higher fresh weight under salinity stress, which was related to a lower concentration of Na⁺ in the shoots. The root-to-shoot transport of ²²Na⁺ was also decreased and was correlated with an upregulation of OsHKT1;5, the native transporter responsible for Na⁺ retrieval from the transpiration stream. Interestingly, in the transgenic Arabidopsis plants overexpressing AtHKT1;1 in the cortex and epidermis, the native AtHKT1;1 gene responsible for Na⁺ retrieval from the transpiration stream, was also upregulated. Extra Na⁺ retrieved from the xylem was stored in the outer root cells and was correlated with a significant increase in expression of the vacuolar pyrophosphatases (in Arabidopsis and rice) the activity of which would be necessary to move the additional stored Na⁺ into the vacuoles of these cells. This work presents an important step in the development of abiotic stress tolerance in crop plants via targeted changes in mineral transport.     

CO migration pathways in cytochrome P450cam studied by molecular dynamics simulations

Previous laser flash photolysis investigations between 100 and 300 K have shown that the kinetics of CO rebinding with cytochrome P450(cam)(camphor) consist of up to four different processes revealing a complex internal dynamics after ligand dissociation. In the present work, molecular dynamics simulations were undertaken on the ternary complex P450(cam)(cam)(CO) to explore the CO migration pathways, monitor the internal cavities of the protein, and localize the CO docking sites. One trajectory of 1 nsec with the protein in a water box and 36 trajectories of 1 nsec in the vacuum were calculated. In each trajectory, the protein contained only one CO ligand on which no constraints were applied. The simulations were performed at 200, 300, and 320 K. The results indicate the presence of seven CO docking sites, mainly hydrophobic, located in the same moiety of the protein. Two of them coincide with xenon binding sites identified by crystallography. The protein matrix exhibits eight persistent internal cavities, four of which corresponding to the ligand docking sites. In addition, it was observed that water molecules entering the protein were mainly attracted into the polar pockets, far away from the CO docking sites. Finally, the identified CO migration pathways provide a consistent interpretation of the experimental rebinding kinetics.     

Synthesis of some tropane derivatives of anticipated activity on the reuptake of norepinephrine and/or serotonin

A variety of tropane derivatives 14a–g were prepared via the reaction of the alcohol analogs 12a and 12b with substituted fluorobenzenes 13a–f. The prepared compounds were tested for their activity and selectivity toward the norepinephrine transporter (NET) and serotonin transporter (SERT) using yohimbine-induced mortality and 5-hydroxytryptophan-induced neurotoxicity in mice, respectively. All the tested compounds were found to be NE and 5-HT reuptake inhibitors except 14d which exhibited selective 5-HT reuptake inhibition activity.     

The Relation of Different Crop Roots Exudates to the Survival and Suppressive Effect of Stenotrophomonas maltophilia (PD4560), Biocontrol Agent of Bacterial Wilt of Potato

Experiments were performed under greenhouse conditions to control bacterial wilt of potato (potato brown rot), caused by Ralstonia solanacearum race 3 biovar 2, Phylotype II, sequevar 1 using various biocontrol strategies. These strategies involved the use of the bacterial biocontrol agent Stenotrophomonas maltophilia (PD4560), in clay or sandy soils, planted with cowpea, maize or tomato which was grown separately in different pots in the inoculated soils. After harvest, the soil derived from each cultivated crop was inoculated with a mixture of three virulent R. solanacearum strains (K3, K10 and K16) to achieve a final concentration of 5 × 10⁸ cfu/g dry soil and used in pots under greenhouse conditions to cultivate potato seed tubers. The highest survival of S. maltophilia in soil (more than 160 days) coincided with a remarkable suppressing effect on disease incidence caused by R. solanacearum that expressed by wilt severity (up to 100% reduction), area under disease progress curve (AUDPC) (up to 99% reduction) and counts of the pathogen in soil (up to 75% reduction), rhizosphere (up to 80% reduction) and plant tissue (up to 97% reduction) of potato plants. The amino acid analysis of root exudates of crops under investigation revealed high percentages of asparagines (15.5–21%), glutamine (16–20%) and sulphur‐containing methionine (7–9%) in both of the cowpea and maize, respectively. In tomato root exudates, high percentages of arginine (around 26%) and lysine (around 23%) were detected. Methionine is known to favour the growth of S. maltophilia suggesting that especially cowpea and maize are suitable for crop rotation with potato and will enhance the sustainability of the biocontrol agent S. maltophilia.