GA Pretreatment Research Articles

Jasmonates, gibberellins, and powdery mildew modify cell cycle progression and evoke differential spatiotemporal responses along the barley leaf.

Barley (Hordeum vulgare) is an important cereal crop, and its development, defence, and stress responses are modulated by different hormones including jasmonates (JAs) and the antagonistic gibberellins (GAs). Barley productivity is severely affected by the foliar biotrophic fungal pathogen Blumeria hordei. In this study, primary leaves were used to examine the molecular processes regulating responses to methyl-jasmonate (MeJA) and GA to B. hordei infection along the leaf axis. Flow cytometry, microscopy, and spatiotemporal expression patterns of genes associated with JA, GA, defence, and the cell cycle provided insights on cell cycle progression and on the gradient of susceptibility to B. hordei observed along the leaf. Notably, the combination of B. hordei with MeJA or GA pre-treatment had a different effect on the expression patterns of the analysed genes compared to individual treatments. MeJA reduced susceptibility to B. hordei in the proximal part of the leaf blade. Overall, distinctive spatiotemporal gene expression patterns correlated with different degrees of cell proliferation, growth capacity, responses to hormones, and B. hordei infection along the leaf. Our results highlight the need to further investigate differential spatial and temporal responses to pathogens at the organ, tissue, and cell levels in order to devise effective disease control strategies in crops.

Gallic acid protects the liver against NAFLD induced by dust exposure and high-fat diet through inhibiting oxidative stress and repressing the inflammatory signaling pathways NF-kβ/TNF-α/IL-6 in Wistar rats.

Objective:The burden of diseases and death related to environmental pollution is becoming a major public health challenge. This study was designed to evaluate the deleterious effects of a combination of dust exposure and high-fat diet on liver function. Gallic acid as a potent antioxidant was used to prevent/alleviate non-alcoholic fatty liver disease (NAFLD) in rats exposed to dust and HFD. Materials and Methods:24 rats were randomly divided into 3 experimental groups: HFD+Clean air, HFD+N/S+Dust and HFD+gallic acid+Dust. Animals were exposed to CA/ dust for six weeks on alternate days. At the end of the experiments, rats were anesthetized and samples were taken to perform molecular, biomedical, and histopathological evaluations. Results:Dust exposure induced NAFLD features in rats under HFD. Dust exposure and HFD disrupted liver enzymes and lipid profile. Dust exposure and HFD increased liver MDA level, mRNA expression of NF-Kβ, TNF-α, IL-6, Nrf2, HO1 and miRs122, and 34a. Dust+HFD also decreased liver total antioxidant capacity level. Pretreatment with GA improved almost studied variables in the HFD+GA+Dust group. Conclusion:The present study showed that HFD given for 6 weeks and dust exposure induced NAFLD in Wistar rats through inducing oxidative stress. Oxidative stress through activating the inflammatory pathways caused NAFLD features. GA pretreatment by inhibiting oxidative stress, effectively protected liver functions against HFD+Dust induced inflammation.

GA Based Robust Blind Digital Watermarking

A genetic algorithm based robust blind digital watermarking scheme is presented. The experimental results show that our scheme keeps invisibility, security and robustness more likely than other proposals in the literature, thanks to the GA pretreatment.

Efecto de las hormonas vegetales y el fotoperiodo en la producción de microtubérculos de papa (Solanum tuberosum L.)

Existen numerosos factores que afectan la micropropagación y la microtuberización en papa; entre ellos, las hormonas vegetales y el fotoperiodo. Para estudiar el efecto de estos dos factores en las variedades ‘Arbolona negra’ (AN) y ‘Granola’ (G), se cultivaron microesquejes de cada variedad en medio MS líquido con o sin giberelinas (GA) y con 25 g/L de sacarosa e incubados bajo condiciones de luz blanca continua. Para inducir la microtuberización, las vitroplántulas obtenidas fueron sub-cultivadas en medio MS suplementado con 50 g/L sacarosa, tres concentraciones de BA (0, 1 y 5 mg/L) e incubadas bajo diferentes regímenes lumínicos. El pre-tratamiento con GA favoreció el alargamiento del vástago en AN pero no en G. Ambas variedades produjeron el mayor número de microtubérculos en medio MS suplementado con 5 mg/L de BA, bajo condiciones fotoperiódicas, sin la adición previa de GA. El cultivo in vitro de microesquejes de papa en medios de cultivo suplementados con BA y sacarosa, y la incubación bajo condiciones de días cortos permite obtener microtubérculos de papa en condiciones in vitro, en un tiempo más corto que el que podría esperarse en condiciones tradicionales de cultivo.

Role of Gallic Acid Pre-treatment in Inducing the Antioxidant Response of Two Wheat Cultivars Differing in Drought Tolerance

The aim of present study was to identify the optimum concentration of GA in promoting the antioxidant response so that it can be used to lessen the deleterious effects of drought in two differentially drought responsive wheat cultivars, PBW 175 (tolerant) and PBW 621 (sensitive). In comparison to hydroprimed seedlings, 20–140 ppm of GA stimulated seedling growth and unlike other phenolic acids, even at 1000 ppm, it did not show much inhibitory effects. At 6th day after germination (DAG), pre-treatment with 140 ppm of GA led to upregulation of catalase (CAT), peroxidase (POX), ascorbate peroxidase (APX) and glutathione reductase (GR) accompanied by an increase in ascorbate and proline and decline in hydrogen peroxide (H2O2) and malondialdehyde (MDA) contents in the growing tissues of wheat seedlings. Higher phenolic content in the roots and shoots of PBW 175 seedlings was well correlated with lower polyphenol oxidase (PPO) activity and reverse trend was obtained in PBW 621. However, GA pre-treatment resulted in significant increase in total phenolic content of sensitive cultivar. Therefore, pre-treatment with 140 ppm of GA showed the potential of stimulating the activities of H2O2-scavenging enzymes and reducing the lipid peroxidation and cell damage as revealed by lower MDA and H2O2 content. Under water deficit conditions, pre-treatment with 140 ppm of GA led to significant increase in seedling growth of both the cultivars. GA pre-treatment at 80–140 ppm showed maximum potential of augmenting the antioxidant response which can be exploited further to observe its stress mitigating effects in wheat seedlings.

The protective effect of 18β-Glycyrrhetinic acid against UV irradiation induced photoaging in mice

It has been confirmed that repeated exposure of skin to ultraviolet (UV) radiation results in cutaneous oxidative stress and inflammation, which act in concert to cause premature skin aging, well known as photoaging. 18β-Glycyrrhetinic acid (GA), widely used to treat various tissue inflammations, is the main active component of licorice root, and has also been shown to possess favorable anti-oxidative property and modulating immunity function. In the present study, we investigated the potential protective effect of GA on UV-induced skin photoaging in a mouse model. During the experimental period of ten consecutive weeks, the dorsal depilated skin of mice was treated with topical GA for 2hours prior to UV irradiation. The results showed that GA pretreatment significantly alleviated the macroscopic and histopathological damages in mice skin caused by UV. Meanwhile, the data also indicated that GA markedly up-regulated the activities of the antioxidant enzymes (SOD, GSH-Px), and increased the content of skin collagen, while obviously decreased malonaldehyde level and inhibited high expressions of matrix metalloproteinase-1 (MMP-1) and -3 (MMP-3), as well as down-regulated the expression of inflammatory cytokines such as IL-6, TNF-α and IL-10. Taken together, these findings amply demonstrate that GA observably attenuates UV-induced skin photoaging mainly by virtue of its antioxidative and anti-inflammatory properties, as well as regulating the abnormal expression of MMP-1 and MMP-3.

ERKs and mitochondria-related pathways are essential for glycyrrhizic acid-mediated neuroprotection against glutamate-induced toxicity in differentiated PC12 cells.

The present study focuses on the neuroprotective effect of glycyrrhizic acid (GA, a major compound separated from Glycyrrhiza Radix, which is a crude Chinese traditional drug) against glutamate-induced cytotoxicity in differentiated PC12 (DPC12) cells. The results showed that GA treatment improved cell viability and ameliorated abnormal glutamate-induced alterations in mitochondria in DPC12 cells. GA reversed glutamate-suppressed B-cell lymphoma 2 levels, inhibited glutamate-enhanced expressions of Bax and cleaved caspase 3, and reduced cytochrome C (Cyto C) release. Exposure to glutamate strongly inhibited phosphorylation of AKT (protein kinase B) and extracellular signal-regulated kinases (ERKs); however, GA pretreatment enhanced activation of ERKs but not AKT. The presence of PD98059 (a mitogen-activated protein/extracellular signal-regulated kinase kinase [MEK] inhibitor) but not LY294002 (a phosphoinositide 3-kinase [PI3K] inhibitor) diminished the potency of GA for improving viability of glutamate-exposed DPC12 cells. These results indicated that ERKs and mitochondria-related pathways are essential for the neuroprotective effect of GA against glutamate-induced toxicity in DPC12 cells. The present study provides experimental evidence supporting GA as a potential therapeutic agent for use in the treatment of neurodegenerative diseases.

Toona sinensis inhibits LPS-induced inflammation and migration in vascular smooth muscle cells via suppression of reactive oxygen species and NF-κB signaling pathway.

Toona sinensis is one of the most popular vegetarian cuisines in Taiwan and it has been shown to possess antioxidant, antiangiogenic, and anticancer properties. In this study, we investigated the antiatherosclerotic potential of aqueous leaf extracts from Toona sinensis (TS; 25–100 μg/mL) and its major bioactive compound, gallic acid (GA; 5 μg/mL), in LPS-treated rat aortic smooth muscle (A7r5) cells. We found that pretreatment with noncytotoxic concentrations of TS and GA significantly inhibited inflammatory NO and PGE2 production by downregulating their precursors, iNOS and COX-2, respectively, in LPS-treated A7r5 cells. Furthermore, TS and GA inhibited LPS-induced intracellular ROS and their corresponding mediator, p47phox. Notably, TS and GA pretreatment significantly inhibited LPS-induced migration in transwell assays. Gelatin zymography and western blotting demonstrated that treatment with TS and GA suppressed the activity or expression of MMP-9, MMP-2, and t-PA. Additionally, TS and GA significantly inhibited LPS-induced VEGF, PDGF, and VCAM-1 expression. Further investigation revealed that the inhibition of iNOS/COX-2, MMPs, growth factors, and adhesion molecules was associated with the suppression of NF-κB activation and MAPK (ERK1/2, JNK1/2, and p38) phosphorylation. Thus, Toona sinensis may be useful for the prevention of atherosclerosis.

Surface morphology of GaN nanorods grown by catalyst-free hydride vapor phase epitaxy

GaN nanorods were grown on c-plane sapphire substrates by using catalyst-free hydride vapor phase epitaxy (HVPE). The effects of substrate temperature, Ga boat temperature, and Ga pretreatment on the surface morphology of GaN nanorods were investigated. From the dependence of a radial and axial growth rate on the substrate temperature, the kinetically limited process was found to be a rate determining step in the growth of GaN nanorods in HVPE. In addition, the activation energy of the growth along the both axial and radial directions were estimated. The dependence of a Ga boat temperature and the Ga pretreatment effect revealed that the density of nanorods were dependent on the flux of Ga species on the substrate.

Enhanced Response of Bean (Phaseolus vulgaris) and Canada Thistle (Cirsium arvense) to Bentazon or Glyphosate by Gibberellin

Gibberellin-enhanced response of bean plants (Phaseolus vulgarisL. ‘Black Valentine’) and Canada thistle [Cirsium arvense(L.) Scop.] to bentazon [3-isopropyl-1H-2,1,3-benzothiadiazin-4(3H)-one 2,2-dioxide] and glyphosate [N-(phosphonomethyl)glycine] was determined on both species under controlled photoperiods in the growth chamber and on Canada thistle under natural conditions in the field. Pretreatment of bean plants in the growth chamber with 10 mg/L gibberellin (GA3or GA4/7) more than doubled the herbicidal effect of 1600 mg/L bentazon treatments. Pretreatment of Canada thistle plants in the growth chamber with 100 mg/L GA4/7increased the herbicidal effect of 50 mg/L bentazon applications more than four-fold, and that of 400 mg/L glyphosate applications by more than two-fold. The phytotoxicity of bentazon to field-grown Canada thistle increased 10% or more in populations pretreated with 25 g/ha gibberellin; and that of 840 g/ha glyphosate was similarly increased. The effectiveness of a higher glyphosate dosage (1680 g/ha) was not significantly increased by GA pretreatment. Plants induced to bolt with gibberellin (GA4/7) were injured more by bentazon than were plants that bolted naturally.

The Influence of Humidity and Gibberellic Acid on Movement and Immobilization of Radiocarbon within Petioles of Coleus blumei Benth. after Application of Indole-3- (Acetic Acid-2-14C) to Leaves of Intact Plants )

Summary Auxin transport and immobilization of radiocarbon in petioles of intact plants of Coleus blumei Benth. as influenced by the humidity of the atmosphere and by preceding and simultaneous treatment with GA 3 were followed 14 h after application of IAA-[2- 14 C] as droplets to the blades of leaves #3 and # 5. The auxin uptake, the fraction remaining transportable and being immobilized within the petioles were much smaller under low humidity (RH ~ 75%) than under high humidity (RH 100%); the differences were larger in leaf # 5 than in leaf # 3. With all treatments and in both leaves the amount of transportable and immobilized radiocarbon was high in the apical part of the petioles; the values decreased toward the middle of the petioles and increased to the level of the apical region toward the base of the petioles which includes the abscission layer. The low auxin supply observed under low humidity led to a steeper initial decrease of the transport characteristics in both leaves. GA treatment did not alter the distribution pattern along the petioles in general, neither did it significantly affect the transport characteristics under low humidity conditions; however, under high humidity, GA reduced auxin uptake and the radiocarbon fractions remaining transportable and being immobilized within the sections of both petioles; GA pretreatment was more effective than application simultaneously with IAA. The reduction of the immobilized fractions was strongest near to the base of the # 3 petioles; this may explain the speeding action of GA on abscission observed by Jacobs and Kirk (1966) in # 3 leaves of Coleus . The results have been discussed in connection with a previously developed (Kaldewey and Jacobs 1974) auxin transport and immobilization model which assumes there is a competition between the transport and immobilization systems for the auxin molecules, and GA weakens the transport system.

Influence of GA on Uptake and Accumulation of Naptalam by Bean Plants

Bean plants (Phaseolus vulgaris L. var. Black Valentine) pretreated with gibberellic acid (hereinafter referred to as GA) absorb and accumulate considerably more N-1-naphthylphthalamic acid (naptalam) than untreated plants. All concentrations of GA from 2.9 × 10−6 to 8.6 × 10−4M were effective; peak influence occurred at 6 × 10−4M. Plants pretreated with this concentration took up 58% more naptalam than untreated plants. When the different parts of the plant were analyzed for naptalam separately, the leaf area (on a per g dry weight basis) was influenced most by GA pretreatment. The leaf area of bean plants pretreated with 2.9 × 10−4M contained 212% more naptalam than the leaf area of untreated plants. The leaf area also included all stem and petiole tissue above and including the first true leaves.

Germination of Tea Seeds (Part 3)

An abnormal thickening growth of plumule in tea seeds has been observed for several years on the germination bed which was warmed up artificially in order to accelerate the seed germination.The leaf primordium of this plumule is white and grows abnormally and loses the function of cell division.A series of experiments was carried out with regard to the abnormal thickening of plumule varied with the varieties used, storage and germination temperature, pre-treatment of seed coat, gibberellin (GA) and indole acetic acid (IAA) treatment, etc.It was confirmed that the abnormal growth was caused by a high temperature on the seed bed and also more or less affected by storage temperature. The varietal difference was observed in the rate of occurrence of the abnormal plumule too. The removal of the seed coat and IAA treatment, however, did not influence the occurrence of the thickened plumule.It was found that the abnormal growth was perfectly cheched by the GA pre-treatment, even though the germination temperature was high.From the results, it was concluded that the seed bed for tea plant should be always kept under 25°C, and the GA per-treatment was very useful for checking the abnormal growth.