A new species of Astropecten (Echinodermata: Asteroidea: Paxillosida: Astropectinidae) and a comparison of the Astropecten species from the Gulf of Mexico and the East Florida Shelf.

A new species of Astropecten is described, supported by morphological and molecular evidence, from the Gulf of Mexico and the East Florida Shelf with most specimens from 30-60 m in depth. The new species, A. mcedwardi n. sp., is small, with a maximum major radius 30 mm. Specimens of A. mcedwardi n. sp. have been found in five museums as an undescribed species or misidentified under several names. The spination of the oral surface most closely resembles that of Astropecten antillensis Lütken, 1859 from the Caribbean, but the body form is similar to that of Astropecten duplicatus Gray, 1840, which is found in the same geographic range. Examination of specimens from different collections indicates that the new species may overlap in distribution with A. antillensis along the East Florida Shelf.  Sequencing and phylogenetic analysis of two mitochondrial genes reveal that A. mcedwardi is closely related to A. antillensis but that its phylogenetic lineage is distinct from that of A. antillensis.

Morphological comparison of Astropecten cingulatus and a new species of Astropecten (Paxillosida, Astropectinidae) from the Gulf of Mexico.

Astropecten cingulatus is a conspicuous species, which displays a large superomarginal plate series on the abactinal surface. Herein we describe a new species from off the Texas coast that shows the superficial appearance of A. cingulatus, including these large superomarginal plates, but with armature differing from that of typological A. cingulatus. This species shows the actinal surface of the inferomarginal plates without the squamules present on A. cingulatus. In addition, the adambulacral plates possessed but a single central large spine surrounded by a circle of spines rather than spine rows. The abactinal paxillar region was also very narrow. Statistical analysis of these and other morphological characters showed the specimens differed significantly from those of A. cingulatus. The regression of the slope of R:SM# vs. R was significant but the intercept was not. Therefore the two species are indistinguishable at small sizes based on R:SM. Compared to known Atlantic Astropecten spp. these observed characters warrant the description of a new species, Astropecten karankawai, for the specimens from off the coasts of Texas and Mexico.

Validation of Astropecten jarli Madsen, 1950 and implications for A. cingulatus Sladen, 1883 (Paxillosida: Astropectinidae).

Astropecten is a major paxillosid genus with a widely occurring presence in tropical and temperate seas. Astropecten jarli from off the west coast of Africa, in the Eastern Atlantic Region, was placed in synonymy with Astropecten cingulatus, a widespread species from the Western Atlantic Region, producing the only amphi-Atlantic Astropecten species. Examination of the holotypes of both species and other specimens of A. cingulatus and A. jarli revealed that A. jarli has a greater major radius:minor radius than A. cingulatus at all sizes, a unique adambulacral spine configuration, and different spination on the inferomarginal plates. ANCOVA indicates A. cingulatus and A. jarli have similar major radius:number of superomarginal plates at small sizes but are distinguishable by the number of superomarginal plates in large individuals. The ratio of the width of the paxillar area:width of the superomarginal plates is greater in A. jarli. Some specimens identified as A. cingulatus from the Eastern Atlantic Region do not fit the description of either A. cingulatus or A. jarli. We conclude that A. jarli is morphologically distinct from A. cingulatus and should be recognized as a valid species. Astropecten cingulatus does not have an amphi-Atlantic distribution and is limited to the Western Atlantic Region.

The valence-fluctuating ground state of plutonium.

A central issue in material science is to obtain understanding of the electronic correlations that control complex materials. Such electronic correlations frequently arise because of the competition of localized and itinerant electronic degrees of freedom. Although the respective limits of well-localized or entirely itinerant ground states are well understood, the intermediate regime that controls the functional properties of complex materials continues to challenge theoretical understanding. We have used neutron spectroscopy to investigate plutonium, which is a prototypical material at the brink between bonding and nonbonding configurations. Our study reveals that the ground state of plutonium is governed by valence fluctuations, that is, a quantum mechanical superposition of localized and itinerant electronic configurations as recently predicted by dynamical mean field theory. Our results not only resolve the long-standing controversy between experiment and theory on plutonium's magnetism but also suggest an improved understanding of the effects of such electronic dichotomy in complex materials.

EFFECT OF DIETARY PROTEIN AND CARBOHYDRATE LEVELS ON WEIGHT GAIN AND GONAD PRODUCTION IN THE SEA URCHIN LYTECHINUS VARIEGATUS.

Adult Lytechinus variegatus were fed eight formulated diets with different protein (ranging from 12 to 36%) and carbohydrate (ranging from 21 to 39 %) levels. Each sea urchin (n = 8 per treatment) was fed a daily sub-satiation ration of 1.5% of average body weight for 9 weeks. Akaike information criterion analysis was used to compare six different hypothesized dietary composition models across eight growth measurements. Dietary protein level and protein: energy ratio were the best models for prediction of total weight gain. Diets with the highest (> 68.6 mg P kcal--1) protein: energy ratios produced the most wet weight gain after 9 weeks. Dietary carbohydrate level was a poor predictor for most growth parameters examined in this study. However, the model containing a protein × carbohydrate interaction effect was the best model for protein efficiency ratio (PER). PER decreased with increasing dietary protein level, more so at higher carbohydrate levels. Food conversion ratio (FCR) was best modeled by total dietary energy levels: Higher energy diets produced lower FCRs. Dietary protein level was the best model of gonad wet weight gain. These data suggest that variations in dietary nutrients and energy differentially affect organismal growth and growth of body components.

EFFECT OF DIET QUALITY ON NUTRIENT ALLOCATION TO THE TEST AND ARISTOTLE'S LANTERN IN THE SEA URCHIN LYTECHINUS VARIEGATUS (LAMARCK, 1816).

Small adult (19.50 ± 2.01g wet weight) Lytechinus variegatus were fed eight formulated diets with different protein (12 to 36% dry weight as fed) and carbohydrate (21 to 39 % dry weight) levels. Each sea urchin (n = 8 per treatment) was fed a daily ration of 1.5% of the average body weight of all individuals for 9 weeks. Akaike information criterion scores were used to compare six different dietary composition hypotheses for eight growth measurements. For each physical growth response, different mathematical models representing a priori hypotheses were compared using the Akaike Information Criterion (AIC) score. The AIC is one of many information-theoretic approaches that allows for direct comparison of non-nested models with varying number of parameters. Dietary protein level and protein: energy ratio were the best models for prediction of test diameter increase. Dietary protein level was the best model of test with spines wet weight gain and test with spines dry matter production. When the Aristotle's lantern was corrected for size of the test, there was an inverse relationship with dietary protein level. Log transformed lantern to test with spines index was also best associated with the dietary protein model. Dietary carbohydrate level was a poor predictor for growth parameters. However, the protein × carbohydrate interaction model was the best model of organic content (% dry weight) of the test without spines. These data suggest that there is a differential allocation of resources when dietary protein is limiting and the test with spines, but not the Aristotle's lantern, is affected by availability of dietary nutrients.

Energetic costs of loss and regeneration of arms in stellate echinoderms.

Loss of arms has energetic consequences for stellate echinoderms (crinoids, ophiuroids, and asteroids). The energetic cost of losing an arm includes loss of investment, decrease in ability to obtain nutrients and allocation of nutrients to regeneration of the lost arms at a cost to other body compartments. The cost to other body compartments is low when food availability is very low or very high. The cost becomes apparent when food availability is sufficient to support production but not high enough that the cost of regeneration has no effect on production of other body compartments. Loss of investment is greater in asteroids than in crinoids and ophiuroids because of greater development of the body wall and presence of gonads and pyloric caeca in the arms. The cost of regeneration of organic matter in an arm can be estimated from the amount of organic matter present in intact arms and the cost of anabolism. Protein production is the primary cost of regeneration of an arm because of the high concentration of protein in the regenerated arm and the high anabolic cost of protein production. A major energetic cost of loss of arms that affects regeneration is decrease in food consumption. It is necessary to separate cost of decrease in consumption from cost of regeneration. Comparison of intact and regenerating individuals requires they consume the same amount of food. The cost of regeneration will also be affected by the quality of food because of the nutrient requirements for growth. Because the quantity and quality of the food ingested is not known, it is not possible to quantify the cost of regeneration in the field. Asteroids appear to be a good model for the study of regeneration in the laboratory because it is possible to control the quantity and quality of food they ingest. They are also a good model for the study of the evolutionary significance of regeneration by comparing individuals that have lost arms and are regenerating them to those that have lost arms and are not. The difference in the frequency of loss of arms of species is related to the difference in availability of food and the ability to feed that affect the capacity for re-investment in the lost arm. This is important in considering life-history strategies.

Enhanced immunogenicity of gp120 protein when combined with recombinant DNA priming to generate antibodies that neutralize the JR-FL primary isolate of human immunodeficiency virus type 1.

Strategies are needed for human immunodeficiency virus type 1 vaccine development that improves the neutralizing antibody response against primary isolates of the virus. Here we examined recombinant DNA priming followed by subunit protein boosting as a strategy to generate neutralizing antibodies. Both plasmid-based and recombinant protein envelope (Env) glycoprotein immunogens were derived from a primary viral isolate, JR-FL. Serum from rabbits immunized with either gp120 or gp140 DNA vaccines delivered by gene gun inoculation followed by recombinant gp120 protein boosting was capable of neutralizing JR-FL. Neither the DNA vaccines alone nor the gp120 protein alone generated a detectable neutralizing antibody response against this virus. Neutralizing antibody responses using gp120 DNA and gp140 DNA for priming were similar. The results suggest that Env DNA priming followed by gp120 protein boosting provides an advantage over either approach alone for generating a detectable neutralizing antibody response against primary isolates that are not easily neutralized.

Epitope mapping and biological function analysis of antibodies produced by immunization of mice with an inactivated Chinese isolate of severe acute respiratory syndrome-associated coronavirus (SARS-CoV).

Inactivated severe acute respiratory syndrome-associated coronavirus (SARS-CoV) has been tested as a candidate vaccine against the re-emergence of SARS. In order to understand the efficacy and safety of this approach, it is important to know the antibody specificities generated with inactivated SARS-CoV. In the current study, a panel of twelve monoclonal antibodies (mAbs) was established by immunizing Balb/c mice with the inactivated BJ01 strain of SARS-CoV isolated from the lung tissue of a SARS-infected Chinese patient. These mAbs could recognize SARS-CoV-infected cells by immunofluorescence analysis (IFA). Seven of them were mapped to the specific segments of recombinant spike (S) protein: six on S1 subunit (aa 12-798) and one on S2 subunit (aa 797-1192). High neutralizing titers against SARS-CoV were detected with two mAbs (1A5 and 2C5) targeting at a subdomain of S protein (aa 310-535), consistent with the previous report that this segment of S protein contains the major neutralizing domain. Some of these S-specific mAbs were able to recognize cleaved products of S protein in SARS-CoV-infected Vero E6 cells. None of the remaining five mAbs could recognize either of the recombinant S, N, M, or E antigens by ELISA. This study demonstrated that the inactivated SARS-CoV was able to preserve the immunogenicity of S protein including its major neutralizing domain. The relative ease with which these mAbs were generated against SARS-CoV virions further supports that subunit vaccination with S constructs may also be able to protect animals and perhaps humans. It is somewhat unexpected that no N-specific mAbs were identified albeit anti-N IgG was easily identified in SARS-CoV-infected patients. The availability of this panel of mAbs also provided potentially useful agents with applications in therapy, diagnosis, and basic research of SARS-CoV.

Identification of two neutralizing regions on the severe acute respiratory syndrome coronavirus spike glycoprotein produced from the mammalian expression system.

The Spike (S) protein of the severe acute respiratory syndrome-associated coronavirus (SARS-CoV) plays important roles in viral pathogenesis and potentially in the development of an effective vaccine against this virulent infectious disease. In this study, the codon-optimized S gene of SARS-CoV was synthesized to construct DNA vaccine plasmids expressing either the full-length or segments of the S protein. High titer S-specific immunoglobulin G antibody responses were elicited in rabbits immunized with DNA against various segments of the S protein. Two neutralizing domains were identified on the S protein, one at the N terminus (Ser12-Thr535) and the other near the C terminus (Arg797-Ile1192).

The effect of feeding frequency on consumption of food, absorption efficiency, and gonad production in the sea urchin Lytechinus variegatus.

The frequency of feeding in the field is variable in sea urchins, ranging from nearly continuous to diel or intermittent. It is essential to know the effect of feeding interval on physiological and metabolic processes to understand the basis for production. Lytechinus variegatus (50 mm horizontal diameter) were collected in January 1999 and held in closed-circuit aquaria at 25 degrees C and 35 per thousand salinity. After 9 days without food, individuals were fed one of three treatments: food available ad libitum, food available for 1 day every 2 days or food available for 1 day every 4 days for 28 days. The rate of food consumption per day of all individuals was high the first week of feeding. It then decreased to a lower, constant rate in those fed ad libitum but remained high in those fed one day every 2 or 4 days. The total amount eaten was directly related to frequency of feeding. The apparent dry matter digestibility (absorption efficiency) did not vary with frequency of feeding. As the total amount of energy absorbed was directly related to the frequency of feeding, the increase in the rate of food consumption does not compensate for a decrease in frequency of feeding. Gonad production efficiency was directly related to frequency of feeding. Gonad gross production (assimilation) efficiencies were 8.4, 3.9 and 3.4% for individuals fed every day, or fed one day every 2 and 4 days, respectively. The corresponding gonad net assimilation efficiencies were 12.5, 5.5, and 4.8%. A decrease in frequency of food availability results in use of a greater proportion of the food consumed for maintenance and less for gonad production.

The Effect of 17 ß-Estradiol and Estrone on Intermediary Metabolism of the Pyloric Caeca of the Asteroid Luidia clathrata (Say) Maintained under Different Nutritional Regimes.

Luidia clathrata were fed either a high or low level of food and injected with estradiol, estrone, or seawater for 16 days. In individuals maintained at a low level of food, the weight of the pyloric caeca decreased in all individuals, regardless of hormone injections. Activities of all enzymes in these individuals were lower than in individuals maintained at a high level of food. In the individuals maintained at a low level of food, the activity of GPDH was higher in the pyloric caeca of individuals injected with estradiol and estrone than in those receiving seawater injections; the activity of 6-PGDH decreased in those injected with estrone. In individuals maintained at a high level of food, the activities of glucose-6-phosphate dehydrogenase (G-6-PDH) and 6-phosphogluconate dehydrogenase (6-PGDH) were higher in individuals injected with estradiol than in those receiving seawater injections. Activities of glycerol phosphate dehydrogenase (GPDH) and pyruvate kinase (PK) were not affected. A slight decrease (P<0.1) in the activity of 6-PGDH was seen with injection of estrone. These results suggest that steroids have a role in regulating cellular metabolism in the pyloric caeca, and that nutritional condition influences the response of the pyloric caeca to steroids. In addition, these results indicate that the nutritional condition of the individual directly influences enzyme activities.

Characteristics of foraging in the soft-bottom benthic starfish Luidia clathrata (echinodermata: Asteroidea): prey selectivity, switching behavior, functional responses and movement patterns.

Luidia clathrata show a strong preference for the infaunal bivalve Mulinia lateralis in Tampa Bay, Florida. Quantitative and qualitative changes in diet occurred over a 7-month period. Individuals may shift from intraoral macrofaunal feeding to intra- and extraoral detrital feeding during periods of low macrofaunal availability. In the laboratory L. clathrata showed switching behavior, feeding disproportionately on the most abundant of two simulataneously presented food models. This switching mechanism may be related to either contact-chemoreceptive rejection of lowdensity food or enhanced distance-chemoreception of high density food. The use of standardized food models eliminated the possibility that handling time was important in switching behavior. Both fed and starved individuals showed functional responses to changes in prey density. However starved individuals ingested greater numbers of prey and spent more time foraging than did fed individuals. Switching and functional response behaviors may be important in promoting nutritional uptake and in causing density-dependent mortality of prey populations. Movement patterns of L. clathrata are directional in the absence of bivalve prey, but become non-directional once patches of prey are encountered. This allows individuals to remain in areas of high prey density. Luidia clathrata has characteristics of an optimal forager, where energy is maximized per unit feeding time.