Cation-π interaction of alkali metal ions with C24 fullerene: a DFT study

Using first principle calculations, we investigated cation-π interactions between alkali cations (Li(+), Na(+), and K(+)) and pristine C(24) or doped fullerenes of BC(23), and NC(23). The most suitable adsorption site is found to be atop the center of a six-membered ring of the exterior surface of C(24) molecule. Interaction energies of these cations decreased in the order: Li(+)?>?Na(+)?>?K(+), with values of -31.82, -22.36, and -15.68 kcal mol(-1), respectively. It was shown that the interaction energies are increased and decreased by impurity doping of B and N atoms in adjacent wall of adsorption site, depending on electron donating or receptivity of the doping atoms.     

In vivo induction of necrosis in mice fibrosarcoma via intravenous injection of type B staphylococcal enterotoxin

The bacterial superantigen staphylococcal enterotoxin B (SEB) is a potent inducer of cytotoxic T-cell activity and cytokine production in vivo. We investigated the possibility of the therapeutic application of SEB in patients with fibrosarcoma. The anti-tumor effect of SEB in mice with inoculated fibrosarcoma (WEHI-164) was examined by intravenous (IV) and intratumoral (IT) injection and the sizes of the inoculated tumors, IFN-γ production, and CD4+/CD8+ T cell infiltration were determined. The inoculated tumors were also examined histologically. In the mice in the IV-injected group, a significant reduction (P < 0.02) of tumor size was observed in comparison with mice in the IT-injected and control groups. Furthermore, the mice in the IV-injected group showed significantly higher levels of IFN-γ (P < 0.009) and CD4+/CD8+ T cell infiltration when compared with the other groups (P < 0.02). A significantly higher frequency of necrosis in tumor tissues was also observed in mice in the IV-injected group (P < 0.05). Our present findings suggest that tumor cell death is caused by increased cytotoxic T-cell activity and cytokine levels in response to the IV injection of SEB and that SEB may be a good option for use as a novel therapy in patients with fibrosarcoma. An erratum to this article can be found at     

Dopamine Selectively Sensitizes Dopaminergic Neurons to Rotenone-Induced Apoptosis

Among various types of neurons affected in Parkinson’s disease, dopamine (DA) neurons of the substantia nigra undergo the most pronounced degeneration. Products of DA oxidation and consequent cellular damage have been hypothesized to contribute to neuronal death. To examine whether elevated intracellular DA will selectively predispose the dopaminergic subpopulation of nigral neurons to damage by an oxidative insult, we first cultured rat primary mesencephalic cells in the presence of rotenone to elevate reactive oxygen species. Although MAP2⁺ neurons were more sensitive to rotenone-induced toxicity than type 1 astrocytes, rotenone affected equally both DA (TH⁺) neurons and MAP2⁺ neurons. In contrast, when intracellular DA concentration was elevated, DA neurons became selectively sensitized to rotenone. Raising intracellular DA levels in primary DA neurons resulted in dopaminergic neuron death in the presence of subtoxic concentrations of rotenone. Furthermore, mitochondrial superoxide dismutase mimetic, manganese (III) meso-tetrakis (4-benzoic acid) porphyrin, blocked activation of caspase-3, and consequent cell death. Our results demonstrate that an inhibitor of mitochondrial complex I and increased cytosolic DA may cooperatively lead to conditions of elevated oxidative stress and thereby promote selective demise of dopaminergic neurons.     

Lack of association between cyclooxygenase 2−765G/C gene polymorphism and breast cancer risk in Ahvaz, west-south Iran

Cyclooxygenases are key enzymes in conversion of arachidonic acid into prostaglandin H2. Cyclooxygenase-2 (COX-2) increases prostaglandins in neoplastic tissue. COX-2 has important roles in cell proliferation cancers, angiogenesis, and alzheimer. COX-2 is up-regulated in several types of cancer, and it is hypothesized that COX-2 expression may be genetically influenced. Our main objective was to evaluated the association of polymorphism COX-2 with risk of breast cancer in khouzestan province, and the second objective of the study was to evaluate the association with biochemistry parameters. This study consisting of 150 patients with breast cancer and 120 normal DNA was extracted from the white blood cells. Polymorphism cox2 gene was detected by polymerase chain reaction according to the standard methods. The profile lipids and estrogen were measured in two groups by standard methods. Chi square analysis showed that there was no association between breast cancer risk and COX-2 ?765G>C genotype and alleles. Also, no association were observed between ?765G>C polymorphism and biochemistry parameters. A multiple logistic regression model with cox2 genotypes and LDL and HDL as covariates revealed that there is no significant association between cox2 genotypes and risk of breast cancer, but higher values of LDL and HDL significantly increase risk of breast cancer.     

Crop mixtures: does niche complementarity hold for belowground resources? An experimental test using rice genotypic pairs

Aims

A growing body of research supports the feasibility of biocrust rehabilitation. Identifying populations of key species that are amenable to cultivation and that are resilient in rehabilitation contexts would advance the efficacy of these technologies. Here we investigate the growth and stress response of the cosmopolitan biocrust moss, Syntrichia ruralis.

Methods

We sampled populations of S. ruralis along a precipitation seasonality gradient from the Colorado Plateau ecoregion of the western United States. We cultivated these populations in an experiment manipulating duration of hydration periods on a weekly cycle. We then treated greenhouse grown materials with brief, stressful watering events, measuring how many events they could survive.

Results

All populations grew at an accelerated rate compared to growth in a natural setting, at least doubling biomass in five months. Increasing duration of hydration periods led to more growth in all but one population. Volunteer biocrust algae and cyanobacteria developed during cultivation, and differed among populations. Greenhouse grown mosses differed in their response to stressful watering, with the most susceptible populations dying at half the number events compared to the most tolerant.

Conclusions

These findings argue for informed selection and deployment of Syntrichia ruralis populations for soil rehabilitation.

     

Specialized Plant Metabolism Characteristics and Impact on Target Molecule Biotechnological Production

Plant secondary metabolism evolved in the context of highly organized and differentiated cells and tissues, featuring massive chemical complexity operating under tight environmental, developmental and genetic control. Biotechnological demand for natural products has been continuously increasing because of their significant value and new applications, mainly as pharmaceuticals. Aseptic production systems of plant secondary metabolites have improved considerably, constituting an attractive tool for increased, stable and large-scale supply of valuable molecules. Surprisingly, to date, only a few examples including taxol, shikonin, berberine and artemisinin have emerged as success cases of commercial production using this strategy. The present review focuses on the main characteristics of plant specialized metabolism and their implications for current strategies used to produce secondary compounds in axenic cultivation systems. The search for consonance between plant secondary metabolism unique features and various in vitro culture systems, including cell, tissue, organ, and engineered cultures, as well as heterologous expression in microbial platforms, is discussed. Data to date strongly suggest that attaining full potential of these biotechnology production strategies requires being able to take advantage of plant specialized metabolism singularities for improved target molecule yields and for bypassing inherent difficulties in its rational manipulation.     

Effects of Irrigation Regime and Foliar Application of Salicylic Acid and Spermine on the Contents of Essential Oil and Caffeic Acid Derivatives in Echinacea purpurea L.

Journal of Plant Growth Regulation - This study investigated the effect of irrigation regimes and the foliar application of salicylic acid (SA) and spermine (SPM) on the content of essential oil...     

Interaction of iron nanoparticles with nervous system: an in vitro study

Nanoparticles (NPs) are one of the interesting and widely studying issues mainly because of their particular physico-chemical features and broad applications in the field of biomedical sciences, such as diagnosis and drug delivery. In this study, the interaction of iron nanoparticles (Fe–NPs) with Tau protein and PC12 cell, as potential nervous system models, was investigated with a range of techniques including dynamic light scattering, intrinsic fluorescence spectroscopy, circular dichroism, [(3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-tetrazolium-bromid] assay, and acridine orange/ethidium bromide (AO/EB) dual staining method. An inverse correlation between Stern and Volmer constant (K_SV) and temperature indicated a probable static quenching mechanism occurred between Tau protein and Fe–NPs. The number of binding site (n = 0.86) showed that there is almost one binding site of Fe–NP per protein. The negative values of ?H (?53.21 kJ/mol) and T?S (?42.44 kJ/mol) revealed that Fe–NPs interacts with Tau protein with dominate role of hydrogen bonds and van der Waals interactions and this interaction was spontaneous (?G = ?10.77 kJ/mol). Also, Fe–NPs stabilized the random coil structure of Tau protein. Moreover, Fe–NPs reduced PC12 cells viability by fragmentation of DNA in an apoptotic manner. In conclusion, induced conformational changes of Tau protein and cytotoxicity of PC12 cells by Fe–NP were revealed to be in a concentration and time-dependent manner.