Methyl jasmonate counteracts boron toxicity by preventing oxidative stress and regulating antioxidant enzyme activities and artemisinin biosynthesis in <Emphasis Type="Italic">Artemisia annua</Emphasis> L.

Boron is an essential plant micronutrient, but it is phytotoxic if present in excessive amounts in soil for certain plants such as Artemisia annua L. that contains artemisinin (an important antimalarial drug) in its areal parts. Artemisinin is a sesquiterpene lactone with an endoperoxide bridge. It is quite expensive compound because the only commercial source available is A. annua and the compound present in the plant is in very low concentration. Since A. annua is a major source of the antimalarial drug and B stress is a deadly threat to its cultivation, the present research was conducted to determine whether the exogenous application of methyl jasmonate (MeJA) could combat the ill effects of excessive B present in the soil. According to the results obtained, the B toxicity induced oxidative stress and reduced the stem height as well as fresh and dry masses of the plant remarkably. The excessive amounts of soil B also lowered the net photosynthetic rate, stomatal conductance, internal CO₂ concentration and total chlorophyll content in the leaves. In contrast, the foliar application of MeJA enhanced the growth and photosynthetic efficiency both in the stressed and non-stressed plants. The excessive B levels also increased the activities of antioxidant enzymes, such as catalase, peroxidase and superoxide dismutase. Endogenous H₂O₂ and O₂⁻ levels were also high in the stressed plants. However, the MeJA application to the stressed plants reduced the amount of lipid peroxidation and stimulated the synthesis of antioxidant enzymes, enhancing the content and yield of artemisinin as well. Thus, it was concluded that MeJA might be utilized in mitigating the B toxicity and improving the content and yield of artemisinin in A. annua plant.     

Salicylic acid mitigates salinity stress by improving antioxidant defence system and enhances vincristine and vinblastine alkaloids production in periwinkle [<Emphasis Type="Italic">Catharanthus roseus</Emphasis> (L.) G. Don]

A pot experiment was conducted to find out whether the foliar spray of salicylic acid (SA) could successfully ameliorate the adverse effects of salinity stress on periwinkle. Thirty-day-old plants were supplied with Control; 0 mM NaCl + 10⁻⁵ M SA (T₁); 50 mM NaCl + 0 SA (T₂); 100 mM NaCl + 0 SA (T₃); 150 mM NaCl + 0 SA (T₄); 50 mM NaCl + 10⁻⁵ M SA (T₅); 100 mM NaCl + 10⁻⁵ M SA (T₆); 150 mM NaCl + 10⁻⁵ M SA (T₇). The plants were sampled 90 days after sowing to assess the effect of SA on stressed and unstressed plants. Salt stress significantly reduced the growth attributes including plant height, leaf-area index, shoot and root fresh weights, shoot and root dry weights. Increasing NaCl concentrations led to a gradual decrease in photosynthetic parameters and activities of nitrate reductase and carbonic anhydrase. Ascorbic acid, total alkaloids and antioxidants enzymes superoxide dismutase, catalase and peroxidase also declined in NaCl-treated plants. The plants, undergoing NaCl stress, exhibited a significant increase in electrolyte leakage and proline content. Foliar application of SA (10⁻⁵ M) reduced the damaging effect of salinity on plant growth and accelerated the restoration of growth processes. It not only improved the growth parameters but also reversed the effects of salinity. Total alkaloid content was improved by SA application both in unstressed and stressed plants. The highest level of total alkaloid content recorded in leaves of SA-treated stressed plants was 11.1%. Foliar spray of SA overcame the adverse effect of salinity by improving the content of vincristine (14.0%) and vinblastine (14.6%) in plants treated with 100 M NaCl.     

Chronic oral exposure to the aldehyde pollutant acrolein induces dilated cardiomyopathy

Environmental triggers of dilated cardiomyopathy are poorly understood. Acute exposure to acrolein, a ubiquitous aldehyde pollutant, impairs cardiac function and cardioprotective responses in mice. Here, we tested the hypothesis that chronic oral exposure to acrolein induces inflammation and cardiomyopathy. C57BL/6 mice were gavage-fed acrolein (1 mg/kg) or water (vehicle) daily for 48 days. The dose was chosen based on estimates of human daily unsaturated aldehyde consumption. Compared with vehicle-fed mice, acrolein-fed mice exhibited significant (P < 0.05) left ventricular (LV) dilatation (LV end-diastolic volume 36 ± 8 vs. 17 ± 5 μl), contractile dysfunction (dP/dt(max) 4,697 ± 1,498 vs. 7,016 ± 1,757 mmHg/s), and impaired relaxation (tau 15.4 ± 4.3 vs. 10.4 ± 2.2 ms). Histological and biochemical evaluation revealed myocardial oxidative stress (membrane-localized protein-4-hydroxy-trans-2-nonenal adducts) and nitrative stress (increased protein-nitrotyrosine) and varying degrees of plasma and myocardial protein-acrolein adduct formation indicative of physical translocation of ingested acrolein to the heart. Acrolein also induced myocyte hypertrophy (~2.2-fold increased myocyte area, P < 0.05), increased apoptosis (~7.5-fold), and disrupted endothelial nitric oxide synthase in the heart. DNA binding studies, immunohistochemistry, and PCR revealed significant (P < 0.05) activation of nuclear factor-κB in acrolein-exposed hearts, along with upregulated gene expression of proinflammatory cytokines tumor necrosis factor-α and interleukin-1β. Long-term oral exposure to acrolein, at an amount within the range of human unsaturated aldehyde intake, induces a phenotype of dilated cardiomyopathy in the mouse. Human exposure to acrolein may have analogous effects and raise consideration of an environmental, aldehyde-mediated basis for heart failure.     

Antioxidant response of Cassia angustifolia Vahl. to oxidative stress caused by Mancozeb, a pyrethroid fungicide

Seeds of Cassia angustifolia Vahl., treated with various concentrations (0, 0.1, 0.15, 0.2 and 0.25 %) of Mancozeb, a broad-spectrum contact fungicide, were sown in field conditions to study the effect of the treatments on lipid peroxidation, proline accumulation and modulation of antioxidant system of seedlings obtained. Significant increase over the control was observed in treated plants for thiobarbituric acid-reactive substances content (up to 207 %), proline content (96 %) and total glutathione content (144 %), whereas the total ascorbate content decreased by 44 %. Increased enzymatic activity was recorded for ascorbate peroxidase (63 %), glutathione reductase (154 %) and superoxide dismutase (109 %), whereas catalase activity decreased by 58 % with 0.25 % Mancozeb treatment. The changes observed were dose-dependent, showing a strong correlation with the level of treatment.     

Aromaticity of azines through dyotropic double hydrogen transfer reaction

The thermodynamic stabilities and IR spectra of the three water clusters (H₂O)_20, (H₂O)_54,, and (H₂O)₁₀₀ are studied by quantum-chemical computations. After full optimization of the (H₂O)_20,54,100 structures using the hybrid density functional B3LYP together with the 6-31+G(d,p) basis set, the electronic energies, zero-point energies, internal energies, enthalpies, entropies, and Gibbs free energies of the water clusters at 298 K are investigated. The OH stretching vibrational IR spectra of (H₂O)_20,54,100 are simulated and split into sub-spectra for different H-bond groups depending on the conformations of the hydrogen bonds. From the computed spectra the different spectroscopic fingerprint features of water molecules in different H-bond conformations in the water clusters are inferred.     

Molecular evolution of Dmrt1 accompanies change of sex-determining mechanisms in reptilia

In reptiles, sex-determining mechanisms have evolved repeatedly and reversibly between genotypic and temperature-dependent sex determination. The gene Dmrt1 directs male determination in chicken (and presumably other birds), and regulates sex differentiation in animals as distantly related as fruit flies, nematodes and humans. Here, we show a consistent molecular difference in Dmrt1 between reptiles with genotypic and temperature-dependent sex determination. Among 34 non-avian reptiles, a convergently evolved pair of amino acids encoded by sequence within exon 2 near the DM-binding domain of Dmrt1 distinguishes species with either type of sex determination. We suggest that this amino acid shift accompanied the evolution of genotypic sex determination from an ancestral condition of temperature-dependent sex determination at least three times among reptiles, as evident in turtles, birds and squamates. This novel hypothesis describes the evolution of sex-determining mechanisms as turnover events accompanied by one or two small mutations.     

Tissue culture and genetic analysis of somaclonal variations of Solanum melongena L. cv. Nirrala

The present study was designed to analyze genetically somaclonal variants using biochemical and molecular markers. Efficient tissue culture protocol for Solanum melongena L. cv. Nirrala was developed. Maximum callus induction (100%) was observed for Murashige and Skoog (MS) media supplemented with 2.0 mg L^?1 naphthalene acetic acid +0.5 mg L^?1 6-benzylaminopurine; and nodal explants gave best callusing response (88.8%) as compared to internodes (88.3%) and leaves (87.7%). The best shooting was induced on nodal and internodal callus in the presence of 2.0 mg L^?1 6-benzylaminopurine. Total soluble protein content of callus and regenerated variant plants was estimated for biochemical analysis, and largest amount of soluble protein was found in callus (6.54 mg g^?1 fresh tissue) followed by variant plant grown on 2.0 mg L^?1 6-benzylaminopurine (5.96 mg g^?1 fresh tissue). Random amplification of polymorphic DNA technique was done with five decamer primers (OPC1-OPC5) and maximum polymorphism was detected by OPC 2 (26.99%) among all samples, whereas nodal callus on media containing 1.0 mg L^?1 naphthalene acetic acid +1.0 mg L^?1 6-benzylaminopurine showed highest polymorphism producing 22 bands, out of which 8 bands were polymorphic. The study shows that this marker system can provide better evaluation of genetic variation induced by tissue culture.     

Identification of Anti-ErbB2 Dual Variable Domain Immunoglobulin (DVD-Ig?) Proteins with Unique Activities

Inhibiting ErbB2 signaling with monoclonal antibodies (mAbs) or small molecules is an established therapeutic strategy in oncology. We have developed anti-ErbB2 Dual Variable Domain Immunoglobulin (DVD-Ig) proteins that capture the function of a combination of two anti-ErbB2 antibodies. In addition, some of the anti-ErbB2 DVD-Ig proteins gain the new functions of enhancing ErbB2 signaling and cell proliferation in N87 cells. We further found that two DVD-Ig proteins, DVD687 and DVD688, have two distinct mechanisms of actions in Calu-3 and N87 cells. DVD687 enhances cell cycle progression while DVD688 induces apoptosis in N87 cells. Using a half DVD687, we found that avidity may play a key role in the agonist activity of DVD687 in N87 cells.