Inhibition of gap junction and adherens junction assembly by connexin and A-CAM antibodies

We examined the roles of the extracellular domains of a gap junction protein and a cell adhesion molecule in gap junction and adherens junction formation by altering cell interactions with antibody Fab fragments. Using immunoblotting and immunocytochemistry we demonstrated that Novikoff cells contained the gap junction protein, connexin43 (Cx43), and the cell adhesion molecule, A-CAM (N-cadherin). Cells were dissociated in EDTA, allowed to recover, and reaggregated for 60 min in media containing Fab fragments prepared from a number of antibodies. We observed no cell-cell dye transfer 4 min after microinjection in 90% of the cell pairs treated with Fab fragments of antibodies for the first or second extracellular domain of Cx43, the second extracellular domain of connexin32 (Cx32) or A-CAM. Cell-cell dye transfer was detected within 30 s in cell pairs treated with control Fab fragments (pre-immune serum, antibodies to the rat major histocompatibility complex or the amino or carboxyl termii of Cx43). We observed no gap junctions by freeze-fracture EM and no adherens junctions by thin section EM between cells treated with the Fab fragments that blocked cell-cell dye transfer. Gap junctions were found on approximately 50% of the cells in control samples using freeze-fracture EM. We demonstrated with reaggregated Novikoff cells that: (a) functional interactions of the extracellular domains of the connexins were necessary for the formation of gap junction channels; (b) cell interactions mediated by A-CAM were required for gap junction assembly; and (c) Fab fragments of antibodies for A-CAM or connexin extracellular domains blocked adherens junction formation

AFM imaging and plasmonic detection of organic thin-films deposited on nanoantenna arrays

In this study, atomic force microscopy (AFM) imaging has been used to reveal the preferential deposition of organic thin-films on patterned nanoantenna array surfaces - identifying the localised formation of both monolayer and multilayer films of octadecanethiol (ODT) molecules, depending on the concentration of the solutions used. Reliable identification of this selective deposition process has been demonstrated for the first time, to our knowledge. Organic thin-films, in particular films of ODT molecules, were deposited on plasmonic resonator surfaces through a chemi-sorption process - using different solution concentrations and immersion times. The nanoantennas based on gold asymmetric-split ring resonator (A-SRR) geometries were fabricated on zinc selenide (ZnSe) substrates using electron-beam lithography and the lift-off technique. Use of the plasmonic resonant-coupling technique has enabled the detection of ODT molecules deposited from a dilute, micromolar (1 M) solution concentration - with attomole sensitivity of deposited material per A-SRR – a value that is three orders of magnitude lower in concentration than previously reported. Additionally, on resonance, the amplitude of the molecular vibrational resonance peaks is typically an order of magnitude larger than that for the non-resonant coupling. Fourier-transform infrared (FTIR) spectroscopy shows molecule specific spectral responses – with magnitudes corresponding to the different film thicknesses deposited on the resonator surfaces. The experimental results are supported by numerical simulation

Microsatellite primers for the rare sedge Lepidosperma bungalbin (Cyperaceae)

Premise of the study: Microsatellite markers were developed for the rare sedge Lepidosperma bungalbin (Cyperaceae) to assess genetic variation and its spatial structuring. Methods and Results: We conducted shotgun sequencing on an Illumina MiSeq and produced 6,215,872 sequence reads. The QDD pipeline was used to design 60 primer pairs that were screened using PCR. We developed 17 loci, of which 12 loci were identified that were polymorphic, amplified reliably, and could be consistently scored. We then screened these loci for variation in individuals from three populations. The number of alleles observed for these 12 loci across the three populations ranged from nine to 19 and expected heterozygosity ranged from 0.41 to 0.89. Conclusions: These markers will enable the quantification of the potential impact of mining on genetic variation within L. bungalbin and establish a baseline for future management of genetic variation of the rare sedge

Deposition of Organic Molecules on Gold Nanoantennas for Sensing

The deposition of organic molecules on gold nanoantennas is reported through chemisorption for sensing in the midinfrared (mid-IR) spectral range. The specific nanostructures are gold asymmetric-split ring resonators (A-SRRs) based on circular-geometry with two different ‘arc’ lengths. The plasmonic resonant coupling technique was used to match the vibrational responses of the targeted molecules for their enhanced detection. Gold nanostructures are functionalised through chemisorption of octadecanethiol (ODT) in ethanol solution. The molecular vibrational responses were measured using a microscope coupled Fourier Transform Infrared (FTIR) spectroscopy. The experimental findings are closely supported using FDTD simulation. The modified nanoantennas surfaces are capable of supporting wide range of organic-sensing applications

Expertise in Trial Advocacy: Some Considerations for Inquiry into Its Nature and Development

It is the central thesis of this paper that what is needed to assess the validity of many of the criticisms directed toward legal practice and training, and to resolve many of the controversies surrounding attempts to correct these criticisms, is a representation or documentation of the structure of expertise in legal practice - especially in trial advocacy since this represents the focus of most complaints. Without such a representation it is difficult to support allegations of incompetence or to defend the efficiency of specific reform on other than subjective or intuitive grounds. At this time no systematic representation exists

A Review of Issues Pertaining to Transgenic Turfgrasses

Recombinant DNA technology is a rapidly growing field in plant and animal breeding. This technology involves the transfer of pieces of DNA, or genes, regardless of the organisms involved or how they are related. Transformation procedures in plants were first developed for important crop and model plant systems. Although turfgrass management and production is one of the fastest growing areas of agriculture, genetic transformation of turfgrasses lags behind that of many other important crop plants. Turfgrasses are becoming more important primarily because of their association with the ever-increasing urban population. The size of the turfgrass seed market is second only to that of hybrid seed corn (Lee, 1996). However, much less is known about the genetics and physiology of turfgrasses. Many are polyploid, perennial, and/or outcrossing. These characteristics make them more difficult to study than many other crop plants. Use of transgenic technology in turfgrasses will likely follow as interest and corporate motivations allow. Application of transgenic technology is virtually limitless. The past few years have seen a rapid increase in releases of transgenic plants. Between 1987 and 1997, 3330 permits and notifications were filed with the U.S. Dept. of Agriculture (USDA–APHIS, 1998) for release of genetically engineered organisms in the United States. Twenty-nine percent involved herbicide tolerance and 24% insect resistance. Compared with the major crop species, genetically engineered turfgrasses are uncommon. By Dec. 1998, 31 permits and notifications had been filed on creeping bentgrass (Agrostis stolonifera L.) and two notifications on Kentucky bluegrass (Poa pratensis L.) (USDA–APHIS, 1998). But as additional genes are identified and cloned, a myriad of traits will probably be introduced into the turfgrasses. The first applications of transformation in turfgrasses were the incorporation of glufosinate [N,N-bis (phosphomethyl)glycine] resistance into creeping bentgrass (Lee et al., 1996; Liu et al., 1998), allowing application of a very effective nonselective herbicide to control unwanted weeds or other turfgrasses. In the future, recombinant DNA technology may be used to introduce other traits, such as insect resistance, disease resistance, and improved environmental stress tolerance. Transformation technology may offer many economic and agronomic benefits that are difficult or impossible to achieve through traditional breeding techniques (Dale, 1993). Essential steps of recombinant DNA technology include identification of the gene of interest, its isolation (cloning), study of the gene’s function and regulation, and introduction of the gene and expression factors into cells (Marois et al., 1991). Finally, the traits must be evaluated in an agriculturally desirable genotype

Nesting Success and Mortality of Nestlings in a Coastal Alabama Heron - Egret Colony, 1976

A heronry at Cat Island, Alabama was surveyed throughout the 1976 breeding season to determine colony structure and survivability of young Ardeidae during varying weather conditions. A total of 155 nests were tagged and the clutch of each monitored until the nestlings abandoned the nests. Offspring of herons nesting during unfavorable weather conditions of late Spring suffered significantly higher mortality than birds nesting in mid-summer. Species nesting on Cat Island include the Louisiana Heron, Snowy Egret, Great Egret, Cattle Egret, Little Blue Heron, Green Heron, and Glossy Ibis

Force Dynamics in Weakly Vibrated Granular Packings

The oscillatory force F_b^ac on the bottom of a rigid, vertically vibrated, grain filled column, reveals rich granular dynamics, even when the peak acceleration of the vibrations is signicantly less than the gravitational acceleration at the earth's surface. For loose packings or high frequencies, F_b^ac 's dynamics are dominated by grain motion. For moderate driving conditions in more compact samples, grain motion is virtually absent, but F_b^ac nevertheless exhibits strongly nonlinear and hysteretic behavior, evidencing a granular regime dominated by nontrivial force-network dynamics.Comment: 4 pages, 5 figure

Magnetoelectric domains and their switching mechanism in a Y-type hexaferrite

By employing resonant X-ray microdiffraction, we image the magnetisation and magnetic polarity domains of the Y-type hexaferrite Ba$_{0.5}$Sr$_{1.5}$Mg$_2$Fe$_{12}$O$_{22}$. We show that the magnetic polarity domain structure can be controlled by both magnetic and electric fields, and that full inversion of these domains can be achieved simply by reversal of an applied magnetic field in the absence of an electric field bias. Furthermore, we demonstrate that the diffraction intensity measured in different X-ray polarisation channels cannot be reproduced by the accepted model for the polar magnetic structure, known as the 2-fan transverse conical (TC) model. We propose a modification to this model, which achieves good quantitative agreement with all of our data. We show that the deviations from the TC model are large, and may be the result of an internal magnetic chirality, most likely inherited from the parent helical (non-polar) phase.Comment: 9 figure