Plants have evolved several adaptive strategies through physiological changes in response to herbivore attacks. Plant secondary metabolites (PSMs) are synthesized to provide defensive functions and regulate defense signaling pathways to safeguard plants against herbivores. Herbivore injury initiates complex reactions which ultimately lead to synthesis and accumulation of PSMs. The biosynthesis of these metabolites is regulated by the interplay of signaling molecules comprising phytohormones. Plant volatile metabolites are released upon herbivore attack and are capable of directly inducing or priming hormonal defense signaling pathways. Secondary metabolites enable plants to quickly detect herbivore attacks and respond in a timely way in a rapidly changing scenario of pest and environment. Several studies have suggested that the potential for adaptation and/or resistance by insect herbivores to secondary metabolites is limited. These metabolites cause direct toxicity to insect pests, stimulate antixenosis mechanisms in plants to insect herbivores, and, by recruiting herbivore natural enemies, indirectly protect the plants. Herbivores adapt to secondary metabolites by the up/down regulation of sensory genes, and sequestration or detoxification of toxic metabolites. PSMs modulate multi-trophic interactions involving host plants, herbivores, natural enemies and pollinators. Although the role of secondary metabolites in plant-pollinator interplay has been little explored, several reports suggest that both plants and pollinators are mutually benefited. Molecular insights into the regulatory proteins and genes involved in the biosynthesis of secondary metabolites will pave the way for the metabolic engineering of biosynthetic pathway intermediates for improving plant tolerance to herbivores. This review throws light on the role of PSMs in modulating multi-trophic interactions, contributing to the knowledge of plant-herbivore interactions to enable their management in an eco-friendly and sustainable manner. 相似文献
In the current study, biogenic silver nanoparticles (U-AgNPs) were synthesized using marine green macro-algal Ulva lactuca extract, and evaluated mechanism behind its anticancer activity against the Human colon cancer (HCT-116). The biogenic U-AgNPs were characterized using various physiochemical techniques. The TEM micrographs confirmed the spherical morphology of synthesized U-AgNPs, with a mean size of 8–14 nm. EDX spectrum as well as ICP-OES confirmed that AgNPs was nearly 90% purity for silver. FTIR Spectra analysis of U-AgNPs confirmed U. lactuca extract bioactive molecules presence over U-AgNPs surface as a stabilizing agent, thereby improving biocompatibility. The cytotoxicity study revealed the dose dependent cell death in colon cancer cells with no loss of viability in normal human colon epithelial cells. Furthermore, the fluorescence micrographs of nucleus staining assay revealed the DNA fragmentation and nucleus condensation of cancer cells treated with U-AgNPs, indicating an apoptosis-mediated cell death. The western bolt and RT-PCR analysis of U-AgNPs treated cancer cells showed the rise in proapoptotic markers (P53, Bax, and P21) and decline in anti-apoptotic markers (Bcl-2), thus confirming the p53-dependent apoptosis mediated cell death in HCT-116. Overall, our study concluded that novel biogenic U-AgNPs nanoparticles, synthesized using marine green macro-algal U. lactuca extract showed efficient anticancer activity against HCT-116 cell line and hence could work as potential therapeutic agent for targeted anti-cancer therapy.
Magnesium aluminate (MgAl2O4) spinel powders of irregular and spherical morphologies were obtained from the bi-component water-based sols following the sol–gel and sol–emulsion–gel methods, respectively. For the synthesis of the oxide microspheres, the surfactant concentration and viscosity of the sols were found to affect the characteristics of the derived microspheres. The gel and calcined powders were investigated by using thermogravimetry analysis, differential thermal analysis, X-ray diffraction (XRD), optical and scanning electron microscopy (SEM), Fourier transformed infrared spectroscopy, and particle size analysis. XRD results indicated crystallization of the only phase MgAl2O4 spinel from 200° to 1000°C. Formation of hollow microspheres with a single cavity was identified by SEM. 相似文献
Recurrent stenosis due to neo‐intimal hyperplasia leads to loss of patency in an established hemodialysis access. The current treatment strategy to maintain patency involves percutaneous transluminal angioplasty with or without stent placement. There are several key points that an interventionalist needs to weigh before deciding to place a stent. These include appropriateness of stent placement, the long term consequences, the type of stent to be deployed, the size of stent and finally the impact on cannulation during dialysis. A general nephrologist needs to be aware of the various benefits and pitfalls of stent placement. The current review provides basic information that will educate the dialysis provider about stents and its use in treating dysfunctional hemodialysis access using commonly encountered clinical scenarios. 相似文献
Porous Si3N4–Si2N2O bodies fabricated by multi-pass extrusion process were investigated depending on the feldspar addition content (4–8 wt% Si)
in the raw silicon powder. The diameter of the continuous pores was about 250 μm. The polycrystalline Si2N2O fibers observed in the continuous pores as well as in the matrix regions of the nitrided bodies can increase the filtration
efficiency. In the 4 wt% feldspar addition, the diameter of the Si2N2O fibers in the continuous pores of the nitrided bodies was about 90–150 nm. A few number of rope typed Si2N2O fibers (∼4 μm) was found in the case of 8 wt% feldspar addition. However, in the 8 wt% feldspar addition, the matrix showed
highly porous structure composed of large number of the Si2N2O fibers (∼60 nm). The relative densities of the Si3N4–Si2N2O bodies with 4 wt% and 8 wt% feldspar additions were about 65% and 61%, respectively. 相似文献
Identifying and separating a subpopulation of cells from a heterogeneous mixture are essential elements of biological research. Current approaches require detailed knowledge of unique cell surface properties of the target cell population. A method is described that exploits size differences of cells to facilitate selective intracellular delivery using a high throughput microfluidic device. Cells traversing a constriction within this device undergo a transient disruption of the cell membrane that allows for cytoplasmic delivery of cargo. Unique constriction widths allow for optimization of delivery to cells of different sizes. For example, a 4 μm wide constriction is effective for delivery of cargo to primary human T‐cells that have an average diameter of 6.7 μm. In contrast, a 6 or 7 μm wide constriction is best for large pancreatic cancer cell lines BxPc3 (10.8 μm) and PANC‐1 (12.3 μm). These small differences in cell diameter are sufficient to allow for selective delivery of cargo to pancreatic cancer cells within a heterogeneous mixture containing T‐cells. The application of this approach is demonstrated by selectively delivering dextran‐conjugated fluorophores to circulating tumor cells in patient blood allowing for their subsequent isolation and genomic characterization. 相似文献
Multiple simultaneous interactions between receptors and ligands dictate the extracellular and intracellular activities of cells. The concept of programmable ligand display is generally used to study the interaction between ligands, displayed on surfaces at various densities, with receptors present on cell surfaces. Various strategies are discussed here to display ligands on surfaces to study their effect on cell behavior. Only very few strategies have been reported where this display combines precise control over density with lateral spacing of ligands on surfaces. In this review, selected examples of strategies to control ligand density and spacing and their implications for biological functions of cells are discussed. 相似文献
Transport sector in India accounts for 20 % of total commercial energy demand of the country, of which a considerable amount is consumed in the form of liquid and gaseous fuel. A major part of these fuels are imported by the Government. Apart from the import expenditure, Government of India has subsidized these fuels to make it available at affordable prices. To check the financial burden and achieve environmental benefits, technical advancement in present system or alternative infrastructure is required. The present study examines the possible impacts on economy and environment by the implementation of battery electric vehicles (BEVs) along with the conventional road transport system in metropolitans with a case study of Kolkata. The major impact has been observed in controlling the vehicular emission with a decrease in CO2 level by 26.27 t per day, on replacement of only 2 % of the present public transport by suitable BEVs. Maintaining similar service for the passengers the electrical energy required by the alternative vehicles has been estimated to be 41,766 kWh per day. This energy has been proposed to be supplied by remodeled fuel stations equipped with solar photovoltaic systems, if charging strategy is based on renewable sources. In case of fuel economy, the infrastructure has shown the potential in reducing the consumption of diesel and autogas (LPG) by 11,654 and 3,256 liter per day, respectively. 相似文献
Coke microtexture and microstructure is a function of feed coal composition and carbonisation process. If the process remains constant, the composition plays a vital role in developing the microtexture and microstructure which also reflects the coke quality. Knowledge of the influence of coal composition and characteristics on coke quality is a must for formulating a coal blend for coke making. To better understand how the coal transforms into coke requires the ability to correlate the microtextural and microstructural features to coal properties. Petrography is an important tool for comparing the feed coal and corresponding coke. In the present study, cokes manufactured from single coals and two-component blends under similar coking conditions were studied under the microscope to provide valuable information to coke makers. Not only the rank and quantification of macerals but also the association of macerals and minerals play an important role. Also the size and type of inertinite affect the coke quality. Micro-cracking, crack lengths and fissures identify the zone of weakness, whereas microtexture of cell walls suggests the strength-controlling parameters of coke. Pictorial concept followed in the present study is given below: 相似文献
Chassis serves as a backbone by supporting the body and diverse parts of the automobile. It ought to be sufficiently rigid to endure the shock, twist, vibration and extra stresses. Then, a vital consideration in chassis design is the strength (Equivalent Stress) for sufficient bending stiffness (Deflection). The primary goal of the research is to build up an Artificial Neural Network (ANN) model for identical stress prediction. Two side members joined to a series of cross members to make the chassis frame. The number of cross members and their locations, cross-section and the sizes of the side and the cross members turn into the design variables. The chassis frame model is created in Creo 3.0 and dissected using Ansys. Since, the number of parameters and levels are more, so the probable models are too much. By changing the Parameters, using the orthogonal array the weight of the sidebar is decreased. Then, FEA is performed on those models. ANN model is prepared by using the results of FEA. For training the ANN model, the standard back-propagation algorithm is observed to be the best. A multi-layer perception network is used for non-linear mapping between the input and the output parameters. FEA-ANN hybrid model can save material used, production cost and time. 相似文献