The aim of this study is to determine the involvement of the flavonol-anthocyanin pathway on plant adaptation to biotic stress using the B.amyloliquefaciens QV15 to trigger blackberry metabolism and ...identify target genes to improve plant fitness and fruit quality. To achieve this goal, field-grown blackberries were root-inoculated with QV15 along its growth cycle. At fruiting, a transcriptomic analysis by RNA-Seq was performed on leaves and fruits of treated and non-treated field-grown blackberries after a sustained mildew outbreak; expression of the regulating and core genes of the Flavonol-Anthocyanin pathway were analysed by qPCR and metabolomic profiles by UHPLC/ESI-qTOF-MS; plant protection was found to be up to 88%. Overexpression of step-controlling genes in leaves and fruits, associated to lower concentration of flavonols and anthocyanins in QV15-treated plants, together with a higher protection suggest a phytoanticipin role for flavonols in blackberry; kempferol-3-O-rutinoside concentration was strikingly high. Overexpression of RuF3H (Flavonol-3-hidroxylase) suggests a pivotal role in the coordination of committing steps in this pathway, controlling carbon flux towards the different sinks. Furthermore, this C demand is supported by an activation of the photosynthetic machinery, and boosted by a coordinated control of ROS into a sub-lethal range, and associated to enhanced protection to biotic stress.
Iron is one of the essential elements for a proper plant development. Providing plants with an accessible form of iron is crucial when it is scant or unavailable in soils. Chemical chelates are the ...only current alternative and are highly stable in soils, therefore, posing a threat to drinking water. The aim of this investigation was to quantify siderophores produced by two bacterial strains and to determine if these bacterial siderophores would palliate chlorotic symptoms of iron-starved tomato plants. For this purpose, siderophore production in MM9 medium by two selected bacterial strains was quantified, and the best was used for biological assay. Bacterial culture media free of bacteria (S) and with bacterial cells (BS), both supplemented with Fe were delivered to 12-week-old plants grown under iron starvation in hydroponic conditions; controls with full Hoagland solution, iron-free Hoagland solution and water were also conducted. Treatments were applied twice along the experiment, with a week in between. At harvest, plant yield, chlorophyll content and nutritional status in leaves were measured. Both the bacterial siderophore treatments significantly increased plant yield, chlorophyll and iron content over the positive controls with full Hoagland solution, indicating that siderophores are effective in providing Fe to the plant, either with or without the presence of bacteria. In summary, siderophores from strain
Chryseobacterium
C138 are effective in supplying Fe to iron-starved tomato plants by the roots, either with or without the presence of bacteria. Based on the amount of siderophores produced, an effective and economically feasible organic Fe chelator could be developed.
Imprinted genes are commonly expressed in mammalian placentas and in plant seed endosperms, where they exhibit preferential uniparental allelic expression. In mammals, imprinted genes directly ...regulate placental function and nutrient distribution from mother to fetus 1–4; however, none of the >60 imprinted genes thus far reported in plants have been demonstrated to play an equivalent role in regulating the flow of resources to the embryo 5–7. Here we show that imprinted Maternally expressed gene1 (Meg1) in maize 8 is both necessary and sufficient for the establishment and differentiation of the endosperm nutrient transfer cells located at the mother:seed interface. Consistent with these findings, Meg1 also regulates maternal nutrient uptake, sucrose partitioning, and seed biomass yield. In addition, we generated an imprinted and nonimprinted synthetic Meg1 (synMeg1) dosage series whereby increased dosage and absence of imprinting both resulted in an unequal investment of maternal resources into the endosperm. These findings highlight dosage regulation by genomic imprinting as being critical for maintaining a balanced distribution of maternal nutrients to filial tissues in plants, as in mammals. However, unlike in mammals, Meg1 is a maternally expressed imprinted gene that surprisingly acts to promote rather than restrict nutrient allocation to the offspring.
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► Imprinted Meg1 is necessary and sufficient for maize transfer cell development ► Meg1 regulates maternal nutrient translocation into the seed and seed biomass yield ► Meg1 dosage is critical for balanced nutrient distribution within the seed ► Imprinting is a potential constraining factor in crop seed improvement
This paper presents several on-chip antenna structures that may be fabricated with standard CMOS technology for use at millimeter wave frequencies. On-chip antennas for wireless personal area ...networks (WPANs) promise to reduce interconnection losses and greatly reduce wireless transceiver costs, while providing unprecedented flexibility for device manufacturers. This paper presents the current state of research in on-chip integrated antennas, highlights several pitfalls and challenges for on-chip design, modeling, and measurement, and proposes several antenna structures that derive from the microwave microstrip and amateur radio art. This paper also describes an experimental test apparatus for performing measurements on RFIC systems with on-chip antennas developed at The University of Texas at Austin.
Silver nanoparticles with different sizes (7, 29, and 89 nm mean values) were synthesized using gallic acid in an aqueous chemical reduction method. The nanoparticles were characterized using ...transmission electron microscopy (TEM), dynamic light scattering (DLS), X-ray diffraction (XRD), and ultraviolet–visible (UV–Vis) absorption spectroscopy; the antibacterial activity was assessed using the standard microdilution method, determining the minimum inhibitory concentration (MIC) according to the National Committee for Clinical Laboratory Standards. From the microscopies studies (TEM) we observed that silver nanoparticles have spherical (7 and 29 nm) and pseudospherical shape (89 nm) with a narrow size distribution. The sizes of the silver nanoparticles were controlled by varying some experimental conditions. It was found that the antibacterial activity of the nanoparticles varies when their size diminishes.
We are reporting an innovative building-block for the development of biosensors based on the non-covalent functionalization of multi-walled carbon nanotubes (MWCNTs) with avidin (MWCNTs-avidin). In ...this work, at variance with previous reports, avidin has the double role of simultaneously being the exfoliating agent of MWCNTs and the platform for anchoring different biotinylated biomolecules. The optimum dispersion was obtained by sonicating for 5.0 min 0.50 mgmL−1 MWCNTs with 1.00 mgmL−1 avidin solution prepared in 50:50 v/v ethanol/water. As proof-of-concept, we immobilized biotinylated horseradish peroxidase (b-HRP) at glassy carbon electrodes (GCE) modified with MWCNTs-avidin to develop a hydrogen peroxide biosensor using hydroquinone as redox mediator. Surface plasmon resonance, electrochemical impedance spectroscopy, cyclic voltammetry and amperometry demonstrated that, even after the partial denaturation of avidin due to the drastic conditions used to functionalize the MWCNTs, it preserves the biorecognition properties and efficiently interacts with biotinylated horseradish peroxidase (b-HRP). The analytical characteristics of the resulting hydrogen peroxide biosensor are the following: linear range between 1.0 × 10−6 M and 1.4 × 10−5 M, sensitivity of (1.37 ± 0.04) x 105 μAM−1, detection limit of 24 nM and reproducibility of 2.9%. The sensor was challenged with different samples, a mouthwash solution, human blood serum and milk, with very good performance.
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•Avidin successfully disperses MWCNTs and provides them of biorecognition properties.•Avidin maintains their recognition properties even after the drastic dispersing conditions.•GCE/MWCNTs-avidin is a versatile platform to immobilize biotynilated residues.•Biotinylated HRP was attached to GCE/MWCNTs-avidin as proof-of-concept.•GCE/MWCNT-avidin/b-HRP allowed the highly sensitive quantification of H2O2.•GCE/MWCNT-avidin/b-HRP was successfully used for detecting of H2O2 in real samples.
The present study focuses on the evaluation of metal (chromium, copper, and lead), arsenic, and pesticide (atrazine and endosulfan) contamination in freshwater streams of one of the most important ...agricultural and industrial areas of central-eastern Argentina, which has not been reported earlier. The environmental fate of inorganic microcontaminants and pesticides was assessed. Samples were collected monthly for a year. Pesticide concentrations were measured in water; metal and arsenic concentrations were measured in water and sediments
,
and physicochemical variables were analyzed. In most cases, metals and arsenic in water exceeded the established guideline levels for the protection of aquatic biota: 98 and 56.25% of the samples showed higher levels of Cr and Pb, while 81.25 and 85% of the samples presented higher values for Cu and As, respectively. Cr, Pb, Cu, and As exceeded 181.5 times, 41.6 times, 57.5 times, and 12.9 times, respectively, the guideline level values. In sediment samples, permitted levels were also surpassed by 40% for Pb, 15% for As, 4% for Cu, and 2% for Cr. Geoaccumulation Index (
Igeo
) demonstrated that most of the sediment samples were highly polluted by Cr and Cu and very seriously polluted by Pb, which indicates progressive deterioration of the sediment quality. Atrazine never exceeded them, but 27% of the 48 water samples contained total endosulfan that surpassed the guidelines. The findings of this study suggest risk to the freshwater biota over prolong periods and possible risk to humans if such type of contaminated water is employed for recreation or human use. Improper disposal of industrial effluents and agricultural runoffs need to be controlled, and proper treatment should be done before disposal to avoid further deterioration of the aquifers of this area.
Plant embryogenesis initiates with the establishment of an apical-basal axis; however, the molecular mechanisms accompanying this early event remain unclear. Here, we show that a small cysteine-rich ...peptide family is required for formation of the zygotic basal cell lineage and proembryo patterning in Arabidopsis. EMBRYO SURROUNDING FACTOR 1 (ESF1) peptides accumulate before fertilization in central cell gametes and thereafter in embryo-surrounding endosperm cells. Biochemical and structural analyses revealed cleavage of ESF1 propeptides to form biologically active mature peptides. Further, these peptides act in a non–cell-autonomous manner and synergistically with the receptor-like kinase SHORT SUSPENSOR to promote suspensor elongation through the YODA mitogen-activated protein kinase pathway. Our findings demonstrate that the second female gamete and its sexually derived endosperm regulate early embryonic patterning in flowering plants.
Herein, the physisorption mechanisms of O2, H2O, CH4, and CO2 molecules on alumina and their effect on electronic properties are investigated. Quantum–classical molecular dynamics simulations and the ...self‐consistent‐charge density‐functional tight‐binding approach are used to dynamically model these mechanisms. Herein, the binding pathways of O, H, and C atoms in the various molecules to Al and O atoms at the top atomic layers of the α‐alumina surface are revealed by the results. Several adsorption sites and molecular orientations relative to Al‐terminated and Ox‐terminated alumina surfaces are examined and it is found that the most stable physisorbed state on the Al‐terminated surface is located above the Al atom, while the Ox‐terminated state is found above the oxygen, resulting in enhanced optical adsorbance. The dissociation of CH4 into CH2+H2 after interaction with the surface results in hydrogen production, but with low adsorbate rates, while O2 molecules primarily bond to the Al atoms, leading to the highest adsorbance rate among the other molecules. Herein, important insights are provided by the findings into the physisorption mechanisms of molecules on alumina and their impact on electronic properties.
Herein, the physisorption mechanisms of O2, H2O, CH4, and CO2 molecules on alumina and their impact on electronic properties are investigated. Quantum–classical molecular dynamics simulations and the self‐consistent‐charge density‐functional tight‐binding approach are used to dynamically model these mechanisms. Methane has low adsorption rates and produces hydrogen via dissociation, while molecular oxygen has high adsorption rates by binding to aluminum atoms.
Dilute isotropic collagen solutions are usually flow processed into monodomain chiral nematic thin films for obtaining highly ordered materials by a multistep process that starts with complex ...inhomogeneous flow kinematics. Here we present rigorous theory and simulation of the initial precursors during flow steps in cholesteric collagen film formation. We first extract the molecular shape parameter and rotational diffusivity from previously reported simple shear data of dilute collagen solutions, where the former leads the reactive parameter (tumbling function) which determines the net effect of vorticity and strain rate on the average orientation and where the latter establishes the intensity of strain required for flow-birefringence, both crucial quantities for controlled film formation flow. We find that the tumbling function is similar to those of rod-like lyotropic liquid crystalline polymers and hence it is predicted that they would tumble in the ordered high concentration state leading to flow-induced texturing. The previously reported experimental data is well fitted with rotational diffusivities whose order of magnitude is consistent to those of other biomacromolecules. We then investigate the response of the tensor order parameter to complex flow kinematics, ranging from pure vorticity, through simple shear, to extensional flow, as may arise in typical flow casting and film flows. The chosen control variable to produce precursor cholesteric films is the director or average orientation, since the nematic order is set close to typical values found in concentrated cholesteric type I collagen solutions. Using the efficient four-roll mill kinematics, we summarize the para-nematic structure-flow process diagram in terms of the director orientation and flow type. Using analysis and computation, we provide a parametric envelope that is necessary to eventually produce well-aligned cholesteric films. We conclude that extensional flow is an essential ingredient of well-ordered film precursors with required Deborah numbers on the order of unity.
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