Relative preference of Lygus hesperus (Hemiptera: Miridae) to selected host plants in the field

Abstract Information on host plant preference of agriculturally important insect pests, such as Lygus hesperus (Knight), can be helpful in predicting its occurrence and future movement among crop and non-crop host plants. A field study was conducted during 2005 and 2006 to evaluate the host preference of Lygus to cotton and four other host plants in the Texas High Plains, including alfalfa (Medicago sativa L.), wild sunflower (Helianthus annuus L.), Russian thistle (Salsola iberica L.) and pigweed (Amaranthus palmeri L.). Sampling for both nymphs and adults during 2005 (July to November) and 2006 (June to November) showed that alfalfa and Russian thistle were the two most preferred hosts out of the five hosts evaluated. Abundance of nymphs (numbers per 50 sweeps per host plant) during the sampling period also indicated the superior reproductive suitability of alfalfa and Russian thistle. Cotton appeared to be the least attractive host plant for Lygus when Russian thistle and alfalfa were available in the host mosaic. Seasonal abundance of Lygus was found to be lower during 2006 compared to 2005, which may be explained by the difference in rainfall patterns during these two years. In terms of species dominance, L. hesperus was the most dominant species in the sampled population followed by an inconsiderable fraction of L. elisus and L. lineolaris.     

Response of cowpea genotypes to zinc in relation to photosynthesis,nodulation and dry matter distribution

Summary Photosynthesis, nodulation and dry matter distribution in four cowpea genotypes were examined at three levels of zinc in soil. Genotypic differences were observed in the extent of depression in yield under zinc deficiency and in the level of zinc requirement. The seed yield response to zinc was reflected mainly on the number of pods, because of better realisation of flowers into pods. These results have been discussed in relation to nodulation, dry matter distribution and zinc uptake in these genotypes.     

Activation of multiple cancer pathways and tumor maintenance function of the 3q amplified oncogene FNDC3B

FNDC3B was recently identified in an oncogenomic screen for amplified oncogenes in hepatocellular carcinoma. It is located at 3q26 and is amplified in over 20% of cancers, usually as part of a broad amplified region encompassing the entire 3q arm. Consistent with an oncogenic role in multiple cancer types, we show here that overexpression of FNDC3B is capable of malignantly transforming mammary and kidney epithelial cells in addition to hepatocytes. To explore how FNDC3B transforms cells, we determined the cellular localization of its gene product and the cancer pathways that it activates. We found that the FNDC3B oncoprotein localizes to the Golgi network, and that its correct localization is essential for its transforming function. We found that overexpression of FNDC3B induces the epithelial-to-mesenchymal transition (EMT) and activates several cancer pathways, including PI3-kinase/Akt, Rb1 and TGFβ signaling. For TGFβ signaling, we analyzed the point in the pathway at which FNDC3B operates and obtained evidence that it induces expression of all three TGFβ ligands and also promotes TGFBR1 cell-surface localization. We found that RNAi-mediated knockdown of FNDC3B in cancer cells with 3q amplification suppressed their clonogenicity and tumorigenicity, but that the same RNAi knockdown had no effect on single-copy 3q cancer cells. These results indicate that FNDC3B is an important oncogenic driver gene of the 3q amplicon, adding to the growing list of oncogenic drivers within this commonly amplified region.     

Evaluating the Performance of Time-Gated Live-Cell Microscopy with Lanthanide Probes

Probes and biosensors that incorporate luminescent Tb(III) or Eu(III) complexes are promising for cellular imaging because time-gated microscopes can detect their long-lifetime (approximately milliseconds) emission without interference from short-lifetime (approximately nanoseconds) fluorescence background. Moreover, the discrete, narrow emission bands of Tb(III) complexes make them uniquely suited for multiplexed imaging applications because they can serve as Förster resonance energy transfer (FRET) donors to two or more differently colored acceptors. However, lanthanide complexes have low photon emission rates that can limit the image signal/noise ratio, which has a square-root dependence on photon counts. This work describes the performance of a wide-field, time-gated microscope with respect to its ability to image Tb(III) luminescence and Tb(III)-mediated FRET in cultured mammalian cells. The system employed a UV-emitting LED for low-power, pulsed excitation and an intensified CCD camera for gated detection. Exposure times of ∼1 s were needed to collect 5–25 photons per pixel from cells that contained micromolar concentrations of a Tb(III) complex. The observed photon counts matched those predicted by a theoretical model that incorporated the photophysical properties of the Tb(III) probe and the instrument’s light-collection characteristics. Despite low photon counts, images of Tb(III)/green fluorescent protein FRET with a signal/noise ratio ≥ 7 were acquired, and a 90% change in the ratiometric FRET signal was measured. This study shows that the sensitivity and precision of lanthanide-based cellular microscopy can approach that of conventional FRET microscopy with fluorescent proteins. The results should encourage further development of lanthanide biosensors that can measure analyte concentration, enzyme activation, and protein-protein interactions in live cells.