Relationship of Aerial Broad Band Reflectance to Meloidogyne incognita Density in Cotton

Aerial images were obtained on 22 July 1999 and 4 August 2000 from five cotton sites infested with Meloidogyne incognita. Images contained three broad bands representing the green (500-600 nm), red (600-700 nm), and near-infrared (700-900 nm) spectrum. Soil samples were collected and assayed for nematodes in the fall at these sites. Sampling locations were identified from images, by locating the coordinates of a wide range of light intensity (measured as a digital number) for each single band, and combinations of bands. There was no single band or band combination in which reflectance consistently predicted M. incognita density. In all 10 site-year combinations, the minimum number of samples necessary to estimate M. incognita density within 25% of the population mean was greater when sampling by reflectance-based classes (3 to 4 per site) than sampling based on the entire site as one unit. Two sites were sampled at multiple times during the growing season. At these sites, there was no single time during the growing season optimal to take images for nematode sampling. Aerial infrared photography conducted during the growing season could not be used to accurately determine fall population densities of M. incognita.     

Genetic structure of a wide-spectrum chicken gene pool

The genetic structure of 65 chicken populations was studied using 29 simple sequence repeat loci. Six main clusters which corresponded to geographical origins and histories were identified: Brown Egg Layers; predominantly Broilers; native Chinese breeds or breeds with recent Asian origin; predominantly breeds of European derivation; a small cluster containing populations with no common history and populations that had breeding history with White Leghorn. Another group of populations that shared their genome with several clusters was defined as 'Multi-clusters'. Gallus gallus gallus (Multi-clusters), one of the subspecies of the Red Jungle Fowl, which was previously suggested to be one of the ancestors of the domesticated chicken, has almost no shared loci with European and White Egg layer populations. In a further sub-clustering of the populations, discrimination between all the 65 populations was possible, and relationships between each were suggested. The genetic variation between populations was found to account for about 34% of the total genetic variation, 11% of the variation being between clusters and 23% being between populations within clusters. The suggested clusters may assist in future studies of genetic aspects of the chicken gene pool.     

Analysis of growth during phototropic curvature of cress hypocotyls

Abstract. Growth rates throughout an organ curving phototropically under continuous, unilateral while light were monitored by lime-lapse photography of cress hypocotyls marked into 1 mm sections by two rows of ion-exchange beads. Curvature resulted from an integrated sequence of changes in growth rate on each side of the organ, but the actual patterns of change and, therefore rales of curvature, differed within even this one species, depending upon the immediate pretreatment of the seedlings. Transference of seedlings from darkness to unilateral irradiation gave immediate growth inhibition on both sides of the organ. Curvature resulted from differential recovery of growth rate, being seen first on the shaded side, most prominently in the apical regions; only 2h after initial exposure to light did growth recover on the lit (lower) side. On the other hand, transfer of seedlings from omnilateral to unilateral irradiation of the same intensity resulted in simultaneous growth inhibition on the irradiated side and stimulated growth on the shaded side: this growth stimulation of the shaded side was greater than occurred in totally darkened control plants.     

Dynamic combinatorial libraries of artificial repeat proteins

Repeat proteins are found in almost all cellular systems, where they are involved in diverse molecular recognition processes. Recent studies have suggested that de novo designed repeat proteins may serve as universal binders, and might potentially be used as practical alternative to antibodies. We describe here a novel chemical methodology for producing small libraries of repeat proteins, and screening in parallel the ligand binding of library members. The first stage of this research involved the total synthesis of a consensus-based three-repeat tetratricopeptide (TPR) protein (～14 kDa), via sequential attachment of the respective peptides. Despite the effectiveness of the synthesis and ligation steps, this method was found to be too demanding for the production of proteins containing variable number of repeats. Additionally, the analysis of binding of the individual proteins was time consuming. Therefore, we designed and prepared novel dynamic combinatorial libraries (DCLs), and show that their equilibration can facilitate the formation of TPR proteins containing up to eight repeating units. Interestingly, equilibration of the library building blocks in the presence of the biologically relevant ligands, Hsp90 and Hsp70, induced their oligomerization into forming more of the proteins with large recognition surfaces. We suggest that this work presents a novel simple and rapid tool for the simultaneous screening of protein mixtures with variable binding surfaces, and for identifying new binders for ligands of interest.     

Quantitative characterization of domes in primary mouse mammary epithelial tumor cell cultures

Summary Dome populations from primary cultures of mouse mammary tumor cells were quantitatively studied in regard to size, distribution, density and the area occupied by light-diffusion photography and image analysis. The effects of fetal bovine serum, insulin and hydrocortisone were analyzed. Quantitative characterization documented dome diameter (mode diameter 0.26 to 0.52 mm), dome area occupied (average 23%, maximum 38.7%), and density (average 78 domes per cm², maximum 117 domes per cm²) for standard culture conditions. Insulin and hydrocortisone had a primary effect on dome density whereas 15% fetal bovine serum had a minimal effect. However, insulin and hydrocortisone had a synergistic optimal effect on dome population. Time-lapse cinematography revealed that the dome population is not static, but a very dynamic one. Domes underwent irregular pulsations of expansion and contraction. Dome enlargement was either by a series of expansions and contractions, by lateral involvement of other cells, or by coalescence of two or more domes. Domes have been considered to be the in vitro counterpart of the in vivo acinus of the mouse mammary gland. However, quantitative dome population characterization has not been available. Dome analysis by light-diffraction photography and image analysis lends itself towards correlative studies of domes and their differentiative products. Supported in part by Public Health Service Contract NO1-CP 61013 within the Virus Cancer Program of the National Cancer Institute and by Public Health Service Training Grant CA05245 from the National Cancer Institute.     

Yeast ARMs (DNA at-risk motifs) can reveal sources of genome instability

The genomes of all organisms contain an abundance of DNA repeats which are at-risk for causing genetic change. We have used the yeast Saccharomyces cerevisiae to investigate various repeat categories in order to understand their potential for causing genomic instability and the role of DNA metabolism factors. Several types of repeats can increase enormously the likelihood of genetic changes such as mutation or recombination when present either in wild type or mutants defective in replication or repair. Specifically, we have investigated inverted repeats, homonucleotide runs, and short distant repeats and the consequences of various DNA metabolism mutants. Because the at-risk motifs (ARMs) that we characterized are sensitive indicators, we have found that they are useful tools to reveal new genetic factors affecting genome stability as well as to distinguish subtle differences between alleles.     

Regional growth patterns in the hypocotyls of etiolated and green cress seedlings in light and darkness

Abstract. A system is described whereby seedling development can be analysed in terms of growth rates of specific 1 mm regions of the hypocotyl. The technique involves time-lapse photography of marked hypocotyls in a specially designed chamber which accommodates seedlings in various orientations with respect to gravity, and under irradiation regimes differing in light quality, quantity and direction. The results of a preliminary study of the upward growth of etiolated or green cress seedlings in darkness or overhead while light are reported. Highest growth rates in etiolated seedlings were observed in zones in the upper one-third of ihe hypocotyl. In green seedlings, growth was more prominent within the subapical zones. Light further restricted growth of the median and basal zones in both types of seedling. However, in their immediate responses to the onset of irradiation, green and etiolated seedlings differed markedly. In etiolated seedlings, recovery of growth at the apex was accompanied by the development of inhibition in the median-basal regions; green seedlings showed a transient inhibition of growth in the apical zone together with a strong immediate inhibition in the median-basal regions.     

A Theft-Resistant Adjustable Security Box for Digital Cameras

Abstract: Remote camera traps are becoming an increasingly popular, affordable, and valuable tool for wildlife research. However, theft and vandalism of these camera systems can result in substantial financial loss and loss of valuable data. We developed an adjustable steel camera security box to protect our Cuddeback® (Non Typical, Inc., Park Falls, WI) digital scouting cameras. Our cameras were deployed for 160 days and experienced no theft or vandalism during that time. Our armored camera box successfully protected our equipment and data, can be sized to accommodate any brand of camera, and can be used in a variety of field situations.     

WDR26 Functions as a Scaffolding Protein to Promote Gβγ-mediated Phospholipase C β2 (PLCβ2) Activation in Leukocytes

We have recently identified WDR26 as a novel WD40 repeat protein that binds Gβγ and promotes Gβγ signaling during leukocyte migration. Here, we have determined the mechanism by which WDR26 enhances Gβγ-mediated phospholipase C β2 (PLCβ2) activation in leukocytes. We show that WDR26 not only directly bound Gβγ but also PLCβ2. The binding sites of WDR26 and PLCβ2 on Gβ₁γ₂ were overlapping but not identical. WDR26 used the same domains for binding Gβγ and PLCβ but still formed a signaling complex with Gβγ and PLCβ2 probably due to the fact that WDR26 formed a higher order oligomer through its Lis homology and C-terminal to LisH (LisH-CTLH) and WD40 domains. Additional studies indicated that the formation of higher order oligomers was required for WDR26 to promote PLCβ2 interaction with and activation by Gβγ. Moreover, WDR26 was required for PLCβ2 translocation from the cytosol to the membrane in polarized leukocytes, and the translocation of PLCβ2 was sufficient to cause partial activation of PLCβ2. Collectively, our data indicate that WDR26 functions as a scaffolding protein to promote PLCβ2 membrane translocation and interaction with Gβγ, thereby enhancing PLCβ2 activation in leukocytes. These findings have identified a novel mechanism of regulating Gβγ signaling through a scaffolding protein.