Competition of haptens

Groups of rabbits were injected with either bovine serum albumin, sheep red cell stroma, or keyhole limpet hemocyanin to which 2,4-dinitrophenyl and/or p-azophenyl arsonate groups had been coupled. Groups of animals received either doubly coupled antigen or an equivalent mixture of singly coupled antigens. Materials were injected intravenously as a solution or subcutaneously and intramuscularly in complete Freund's adjuvant. The presence of dinitrophenyl groups on the immunizing antigen could suppress, partially or completely, the antibody response to p-azophenyl arsonate when this hapten was located on the same molecule. Suppression was dependent on the ratio of haptenic groups on the molecule, appeared to be greatly affected by the method of immunization, and could be demonstrated in all three antigen systems. Partial suppression was manifested in decreased frequency and delayed appearance of the response as well as decreased maximal antibody titers. These findings appear irreconcilable with the possibility of direct clonal selection of antibody-producing cells by unprocessed antigen

Plant Mediated Effects on Tritrophic Interactions in the Solanaceae-Hornworm System

Top-down pressure from parasites is thought to be a key driver in herbivore diet breath, but studies investigating the evolution of food plant shifts as a defense against natural enemies in the environment are still lacking in the literature. I examined how plants alter insect-enemy interactions for a specialist herbivore utilizing solanaceous food plants, Manduca sexta (the tobacco hornworm) and the parasitoid wasp, Cotesia congregata, as a model. In this study, I documented parasite infections in a field population of M. sexta, and then investigated from an eco-immunological perspective how plant toxins influence susceptibility to parasites in order to explain food plant choice. My research demonstrates that M. sexta exhibits a negative preference-performance relationship with plants in the Solanaceae. This is likely to gain protection from parasitoid attack via direct and indirect effects from plants on herbivore physiology. I show that herbivores are unpalatable and toxic to natural enemies when they consume more noxious host plants, but also provide a subsequent explanation for the adaptive value and maintenance of this interaction; specific plant secondary metabolites alter herbivore immune activity, where for M. sexta nicotine demonstrates immunotherapeutic properties by enhancing this insect’s phenoloxidase activity. I also examined phenotypic plasticity in caterpillar immune responses to nonlethal cues from natural enemies. Upon studying non-consumptive effects of natural enemies on M. sexta in the presence of C. congregata and the spined soldier bug, Podisus maculiventris, my work suggests that M. sexta generally accelerates their development in the presence of natural enemies at the cost of some immune defenses, implying a resource allocation tradeoff to physiological development and immunity. Placed within a community level context, M. sexta can mitigate the consumptive and nonconsumptive effects parasitoids have on this herbivore’s physiology by utilizing a food resource in parasite burdened habitats that increases direct resistance to parasites and also improves immune activity, even at the cost of development. Following this, I investigated the consequences of crop domestication on plant-insect-parasitoid interaction via changes in plant traits for direct defense against herbivores and altered plant volatile signaling of natural enemies. I demonstrated that domesticated chili peppers showed no loss of plant direct defenses to M. sexta compared to wild peppers and that crop peppers had increased attraction and efficiency of parasitoids. This highlighted the context-dependent nature domestication has on trophic interactions and emphasizes the need for dedicated investigation in each unique crop system

Alien Registration- Garvey, Amelia A. (Presque Isle, Aroostook County)

https://digitalmaine.com/alien_docs/33770/thumbnail.jp

Research in interactive scene analysis

An interactive scene interpretation system (ISIS) was developed as a tool for constructing and experimenting with man-machine and automatic scene analysis methods tailored for particular image domains. A recently developed region analysis subsystem based on the paradigm of Brice and Fennema is described. Using this subsystem a series of experiments was conducted to determine good criteria for initially partitioning a scene into atomic regions and for merging these regions into a final partition of the scene along object boundaries. Semantic (problem-dependent) knowledge is essential for complete, correct partitions of complex real-world scenes. An interactive approach to semantic scene segmentation was developed and demonstrated on both landscape and indoor scenes. This approach provides a reasonable methodology for segmenting scenes that cannot be processed completely automatically, and is a promising basis for a future automatic system. A program is described that can automatically generate strategies for finding specific objects in a scene based on manually designated pictorial examples

How good are the Garvey-Kelson predictions of nuclear masses?

The Garvey-Kelson relations are used in an iterative process to predict nuclear masses in the neighborhood of nuclei with measured masses. Average errors in the predicted masses for the first three iteration shells are smaller than those obtained with the best nuclear mass models. Their quality is comparable with the Audi-Wapstra extrapolations, offering a simple and reproducible procedure for short range mass predictions. A systematic study of the way the error grows as a function of the iteration and the distance to the known masses region, shows that a correlation exists between the error and the residual neutron-proton interaction, produced mainly by the implicit assumption that $V_{np}$ varies smoothly along the nuclear landscape.Comment: 10 pages, 18 figure

Lateral Exchange of Larval Fish between a Restored Backwater and a Large River in the East-Central USA

Exchange of larval fish between a river\u27s main channel and its floodplain backwaters is compromised by sedimentation. Restoration projects to reduce sediment loading are being implemented in large rivers of the midwestern United States to curb backwater habitat loss and restore backwater-to-river connectivity. During 2004 and 2005, drift nets were set bidirectionally (with and against the flow) within a constructed channel between the Illinois River and an adjacent, 1,100-ha restored backwater, Swan Lake, to investigate the interplay between life history strategies and lateral drift on a diel and seasonal basis. Ambient larval density and species composition within the river and backwater also were quantified. Drift was positively correlated with water velocity in the main stem during 2004, and an estimated 32.3 × 106 larvae drifted at the surface of the channel into Swan Lake. In the absence of a flood in 2005, the density and composition of the larval fish assemblage in Swan Lake and the Illinois River appeared to drive larval drift timing, magnitude, and composition. Swan Lake\u27s restoration has maintained some river connectivity and lateral drift functionality for resident fish, but its functionality compared with natural, connected river–backwater systems remains unknown

Competition between Larval Fishes in Reservoirs: The Role of Relative Timing of Appearance

Funding for this project was provided by National Science Foundation grants DEB 9407859 and DEB 9107173 to R.A.S and Federal Aid in Sport Fish Restoration, project F-69-P, administered jointly by the U. S. Fish and Wildlife Service and the Ohio Division of Wildlife. A Presidential Fellowship from The Ohio State University supported J.E.G. during part of this research.In small, hypereutrophic reservoirs (100 mg total phosphorus/L), larval gizzard shad Dorosoma cepedianum and threadfin shad D. petenense (henceforth, shad) reach high densities in the limnetic zone, virtually eliminate zooplankton, and perhaps compromise success of other planktivorous larvae, such as bluegill Lepomis macrochirus. Because relative timing of appearance of shad and bluegills probably influences their relative success, we quantified densities of fish larvae and zooplankton during spring through summer in three reservoirs across 8 years (1987–1994), and we conducted three hatchery experiments with varying larval appearance times and gizzard shad densities in plastic bags (1 m3). When shad were abundant in reservoirs, bluegill abundance often peaked either at the same time (36% of reservoirs and years combined) or after (40% of reservoirs and years combined) shad peaks. When gizzard shad were placed in bags 2 weeks before bluegills (N = 1 experiment), they depleted zooplankton, reducing growth (~0.075 g · g-1· d-1) but not survival of bluegills. In experiments (N = 2) in which both species were added simultaneously, zooplankton declined only slightly with gizzard shad, and there was little effect on bluegill growth (~0.21 g · g-1· d-1) and survival; in general, gizzard shad growth declined with time and increasing gizzard shad density. Based on experiments, bluegill success should vary among reservoirs and years as a function of their appearance relative to gizzard shad. In reservoirs, zooplankton availability and bluegill abundances were consistently low during years when gizzard shad dominated reservoir fish assemblages. Because gizzard shad probably reduce bluegill success in hypereutrophic Ohio reservoirs, management strategies that reduce gizzard shad should improve bluegill success