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Average annual temperatures in the Arctic increased by 2–3 °C during the second half of the twentieth century. Because shorebirds initiate northward migration to Arctic nesting sites based on cues at distant wintering grounds, climate-driven changes in the phenology of Arctic invertebrates may lead to a mismatch between the nutritional demands of shorebirds and the invertebrate prey essential for egg formation and subsequent chick survival. To explore the environmental drivers affecting invertebrate availability, we modeled the biomass of invertebrates captured in modified Malaise-pitfall traps over three summers at eight Arctic Shorebird Demographics Network sites as a function of accumulated degree-days and other weather variables. To assess climate-driven changes in invertebrate phenology, we used data from the nearest long-term weather stations to hindcast invertebrate availability over 63 summers, 1950–2012. Our results confirmed the importance of both accumulated and daily temperatures as predictors of invertebrate availability while also showing that wind speed negatively affected invertebrate availability at the majority of sites. Additionally, our results suggest that seasonal prey availability for Arctic shorebirds is occurring earlier and that the potential for trophic mismatch is greatest at the northernmost sites, where hindcast invertebrate phenology advanced by approximately 1–2.5 days per decade. Phenological mismatch could have long-term population-level effects on shorebird species that are unable to adjust their breeding schedules to the increasingly earlier invertebrate phenologies.

Co-administration of human secretory IgA (sIgA) together with subtherapeutic vancomycin significantly enhanced survival in the Clostridioides difficile infection (CDI) hamster model . Vancomycin (5 or 10 mg/kgx5 days) + healthy donor plasma sIgA/monomeric IgA (TIDx21 days) or hyperimmune sIgA/monomeric IgA (BIDx13 days) enhanced survival of CDI hamsters. Survival curves were significantly improved compared to vancomycin alone (p=0.018 and 0.039 by log-rank (Mantel-Cox) for healthy, and hyperimmune, sIgA, respectively. Passive immunization with sIgA made with recombinant human secretory component and IgA dimer/polymer from pooled human plasma can be administered orally, and prevents lethal infection in a partially treated CDI hamster model.

Conservation status and management priorities are often informed by population trends. Trend estimates can be derived from population surveys or models, but both methods are associated with sources of uncertainty. Many Arctic-breeding shorebirds are thought to be declining based on migration and/or overwintering population surveys, but data are lacking to estimate the trends of some shorebird species. In addition, for most species, little is known about the stage(s) at which population bottlenecks occur, such as breeding vs. nonbreeding periods. We used previously published and unpublished estimates of vital rates to develop the first large-scale population models for 6 species of Arctic-breeding shorebirds in North America, including separate estimates for 3 subspecies of Dunlin. We used the models to estimate population trends and identify life stages at which population growth may be limited. Our model for the arcticola subspecies of Dunlin agreed with previously published information that the subspecies is severely declining. Our results also linked the decline to the subspecies' low annual adult survival rate, thus potentially implicating factors during the nonbreeding period in the East Asian–Australasian Flyway. However, our trend estimates for all species showed high uncertainty, highlighting the need for more accurate and precise estimates of vital rates. Of the vital rates, annual adult survival had the strongest influence on population trend in all taxa. Improving the accuracy, precision, and spatial and temporal coverage of estimates of vital rates, especially annual adult survival, would improve demographic model-based estimates of population trends and help direct management to regions or seasons where birds are subject to higher mortality.LAY SUMMARYDocumenting population trends is essential for evaluating the conservation status of wild species such as Arctic-breeding shorebirds.Trends can be estimated with population surveys or by predicting population growth based on survival rates and fecundity, but both methods are challenging, especially for species with large or remote geographic distributions.We used recent broad-scale estimates of survival and fecundity to develop population models for 6 species of Arctic-breeding shorebirds.The arcticola subspecies of Dunlin is likely in severe decline, but our trend estimates for all species showed high uncertainty.Uncertainty around the values of annual adult survival rates was a key driver of the uncertainty around the trend estimates.Our work highlights the need for better estimates of annual adult survival, seasonal survival, juvenile survival, and breeding propensity for these Arctic-breeding shorebirds.

Many Arctic shorebird populations are declining, and quantifying adult survival and the effects of anthropogenic factors is a crucial step toward a better understanding of population dynamics. We used a recently developed, spatially explicit Cormack–Jolly–Seber model in a Bayesian framework to obtain broad-scale estimates of true annual survival rates for 6 species of shorebirds at 9 breeding sites across the North American Arctic in 2010–2014. We tested for effects of environmental and ecological variables, study site, nest fate, and sex on annual survival rates of each species in the spatially explicit framework, which allowed us to distinguish between effects of variables on site fidelity versus true survival. Our spatially explicit analysis produced estimates of true survival rates that were substantially higher than previously published estimates of apparent survival for most species, ranging from S = 0.72 to 0.98 across 5 species. However, survival was lower for the arcticola subspecies of ...

The Yukon–Kuskokwim Delta of Alaska, USA is a globally important region for numerous avian species including millions of migrating and nesting waterbirds. However, data on the current spatial distribution of critical nesting areas and the importance of environmental variables in the selection of nest locations are generally lacking for waterbirds in this region. We modeled nest densities for 6 species of geese and eiders that commonly breed on the Yukon–Kuskokwim Delta, including cackling goose (Branta hutchinsii minima), emperor goose (Chen canagica), black brant (B. bernicla nigricans), greater white-fronted goose (Anser albifrons frontalis), spectacled eider (Somateria fischeri), and common eider (S. mollissima). The data used were from single-visit nest searches on 2,318 plots sampled during 29 years from 1985 to 2013. We modeled nest density for each species by combining data across years and using random forests methods and time-static landscape environmental variables. These models provide the first habitat-specific predictive distributions of nest density for these species breeding on the Yukon–Kuskokwim Delta of Alaska. Predictive performance of the random forests models varied among species, explaining 13–69% of the variance in nest density. For most species, nest density was greatest near the coast and within lowland habitats. Predicted nest densities mapped across the coastal zone of the Yukon–Kuskokwim Delta revealed areas of high and low nest densities that can be used to inform management and conservation decisions. © 2017 The Wildlife Society.

River deltas along Alaska’s Beaufort Sea coast are used by hatch-year semipalmated sandpipers (Calidris pusilla) after leaving their terrestrial natal sites, but the drivers of their use of these stopover sites on the first “hop” of fall migration are unknown. We quantified sandpiper temporal distribution and abundance as related to food resources at three river deltas during the beginning of their fall migration (post-breeding period) to compare the habitat quality among these deltas. We conducted population counts, sampled invertebrates, and captured birds to collect blood samples from individuals for triglyceride and stable isotope analyses to determine fattening rates and diet. Patterns of sandpiper and invertebrate abundance were complex and varied among deltas and within seasons. River deltas were used by sandpipers from late July to late August, and peak sandpiper counts ranged from 1000 to 4000 individuals, of which 98% were hatch-year semipalmated sandpipers. Isotopic signatures from blood plasma samples indicated that birds switched from a diet of upland tundra to delta invertebrate taxa as the migration season progressed, suggesting a dependence on delta invertebrates. Despite differences in diet among deltas, we found no differences in fattening rates of juvenile sandpipers as indicated by triglyceride levels. The number of sandpipers was positively associated with abundance of Amphipoda and Oligochaeta at the Jago and Okpilak-Hulahula deltas; an isotopic mixing model indicated that sandpipers consumed Amphipoda and Oligochaeta at Jago, mostly Chironomidae at Okpilak-Hulahula and Spionidae at Canning. Regardless of the difference in sandpiper diets at the Beaufort Sea deltas, their similar fattening rates throughout the season indicate that all of these stopover sites provide a critical food resource for hatch-year sandpipers beginning their first migration.

Semipalmated Sandpiper (Calidris pusilla) populations have undergone significant declines at core nonbreeding sites in northeastern South America. Breeding populations have also declined in the eastern North American Arctic, but appear to be stable or increasing in the central and western Arctic. To identify vulnerable populations and sites, we documented the migratory connectivity of Semipalmated Sandpipers using light-level geolocators, deploying 250 at 8 Arctic sites across the species' breeding range from 2011 to 2015, plus 87 at a single wintering site in northeastern Brazil in 2013 and 2014. We recovered 59 units and resighted 7 more (26% return rate) on the breeding grounds, but none at the nonbreeding site. We recovered only ∼3% of units deployed in 2013 at eastern Arctic breeding sites, but recovered 33% of those deployed in 2015. Overall, birds with geolocators were 57% as likely to return as those carrying alphanumeric flags. Stopover durations at prairie sites (mean: 8.7 days southbou...

Gut microbiota can have important effects on host health, but explanatory factors and pathways that determine gut microbial composition can differ among host lineages. In mammals, host phylogeny is one of the main drivers of gut microbiota, a result of vertical transfer of microbiota during birth. In birds, it is less clear what the drivers might be, but both phylogeny and environmental factors may play a role. We investigated host and environmental factors that underlie variation in gut microbiota composition in eight species of migratory shorebirds. We characterized bacterial communities from 375 fecal samples collected from adults of eight shorebird species captured at a network of nine breeding sites in the Arctic and sub-Arctic ecoregions of North America, by sequencing the V4 region of the bacterial 16S ribosomal RNA gene. Firmicutes (55.4%), Proteobacteria (13.8%), Fusobacteria (10.2%), and Bacteroidetes (8.1%) dominated the gut microbiota of adult shorebirds. Breeding location was the main driver of variation in gut microbiota of breeding shorebirds (R-2 = 11.6%), followed by shorebird host species (R-2 = 1.8%), and sampling year (R-2 = 0.9%), but most variation remained unexplained. Site variation resulted from differences in the core bacterial taxa, whereas rare, lowabundance bacteria drove host species variation. Our study is the first to highlight a greater importance of local environment than phylogeny as a driver of gut microbiota composition in wild, migratory birds under natural conditions. Avian Health Program grants from the U.S. Fish and Wildlife Service [2013-02]; National Science FoundationNational Science Foundation (NSF) [DDIG-1501479]; Arctic Landscape Conservation Cooperative; U.S. Fish and Wildlife ServiceUS Fish & Wildlife Service; Division of Biology at the Kansas State University; Kansas State University Open Access Publishing Fund This work was funded by the Avian Health Program grants from the U.S. Fish and Wildlife Service (to JS and RL, and 2013-02 to KG and RL), a Doctoral Dissertation Improvement Grant from the National Science Foundation (DDIG-1501479 to KG), the Arctic Landscape Conservation Cooperative, the U.S. Fish and Wildlife Service, and the Division of Biology at the Kansas State University. Publication of this article was funded in part by the Kansas State University Open Access Publishing Fund.

Mercury contamination has become a major concern in the Arctic, where elevated mercury deposition has led to large increases in mercury exposure for some Arctic wildlife over the past century. Chronic mercury exposure in birds is known to reduce reproductive success, which may ultimately result in population declines. Many species of Arctic-breeding shorebirds are declining, and exposure to environmental contaminants, such as mercury, may be an important factor. We quantified mercury exposure in 10 shorebird species breeding and staging in Alaska. We analyzed 229 blood and 73 feather samples collected in 2008–2009 for total mercury concentrations. Mercury in blood represents local exposure, whereas mercury in feathers reflects exposure during feather development. Concentrations of mercury ranged from 0.03 to 2.20 μg g−1 in shorebird blood and from 0.16 to 3.66 μg g−1 in shorebird feathers. Most shorebirds sampled during staging had relatively low blood mercury, but some breeding species had suffi...

We investigated the abundance and turnover rate of phalaropes (Red-necked and Red: Phalaropus lobatus, Phalaropus fulicarius) in the outer Bay of Fundy, Canada during migratory stopover in 2008, 2009, and 2010. We describe estimation procedures designed to calculate size of the total stopover population of phalaropes, adjusting for length of stay. A total of 29 aerial surveys were flown in two nonoverlapping survey regions situated off Brier Island, Nova Scotia and Grand Manan, New Brunswick. Line transect distance sampling methods were used to obtain abundance estimates at discrete time steps from aerial surveys. Estimated number of phalaropes by date ranged between 6000-88,000 in 2009 and 31,000-127,000 in 2010. To quantify the cumulative number of phalaropes in the study area, the temporal dimension of stopover passage was incorporated by an analysis of radiotelemetry data to estimate length of stay. A total of 27 phalaropes were captured and fitted with radio transmitters between 2008 and 2010. Estimated length of stay in days was 15.2 ± 1.91 for a time-integrated stopover population of 103,496 phalaropes in 2009 and 287,558 in 2010. This is particularly relevant to the conservation status of P. lobatus in North America, which has been uncertain since the disappearance of that species from an important stopover site in 1990. Our findings emphasize the need for studies that monitor phalaropes at sea, where they spend the majority of their time, as a means to inform effective management and conservation.

We used data from aerial surveys (1992-2010) of >100,000 km(2) and ground surveys (1998-2004) of >150 km(2) to estimate the density and abundance of birds on the North Slope of Alaska (U.S.A.). In the ground surveys, we used double sampling to estimate detection ratios. We used the aerial survey data to compare densities of birds and Arctic fox (Vulpes lagopus), the major nest predator of birds, on the North Slope, in Prudhoe Bay, and in nearby areas. We partitioned the Prudhoe Bay oil field into 2 × 2 km plots and determined the relation between density of aquatic birds and density of roads, buildings, and other infrastructure in these plots. Abundance and density (birds per square kilometer) of 3 groups of aquatic birds-waterfowl, loons, and grebes; shorebirds; and gulls, terns, and jaegers-were highest in the National Petroleum Reserve-Alaska (NPRA) and lowest in the Arctic National Wildlife Refuge. Six other major wetlands occur in the Arctic regions of Canada and Russia, but the largest population of aquatic birds was in the NPRA. Aquatic birds were concentrated in the northern part of the NPRA. For example, an area that covered 18% of the NPRA included 53% of its aquatic birds. The aerial surveys showed that bird density was not lower and fox density was not higher in Prudhoe Bay than in surrounding areas. Density of infrastructure did not significantly affect bird density for any group of species. Our results establish that the NPRA is one of the most important areas for aquatic birds in the Arctic. Our results and those of others also indicate that oil production, as practiced in Prudhoe Bay, does not necessarily lead to substantial declines in bird density or productivity in or near the developed areas. Prioridades para la Conservacion de Aves en el Norte de Alaska.

Background Geolocators are useful for tracking movements of long-distance migrants, but potential negative effects on birds have not been well studied. We tested for effects of geolocators (0.8–2.0 g total, representing 0.1–3.9 % of mean body mass) on 16 species of migratory shorebirds, including five species with 2–4 subspecies each for a total of 23 study taxa. Study species spanned a range of body sizes (26–1091 g) and eight genera, and were tagged at 23 breeding and eight nonbreeding sites. We compared breeding performance and return rates of birds with geolocators to control groups while controlling for potential confounding variables. Results We detected negative effects of tags for three small-bodied species. Geolocators reduced annual return rates for two of 23 taxa: by 63 % for semipalmated sandpipers and by 43 % for the arcticola subspecies of dunlin. High resighting effort for geolocator birds could have masked additional negative effects. Geolocators were more likely to negatively affect return rates if the total mass of geolocators and color markers was 2.5–5.8 % of body mass than if tags were 0.3–2.3 % of body mass. Carrying a geolocator reduced nest success by 42 % for semipalmated sandpipers and tripled the probability of partial clutch failure in semipalmated and western sandpipers. Geolocators mounted perpendicular to the leg on a flag had stronger negative effects on nest success than geolocators mounted parallel to the leg on a band. However, parallel-band geolocators were more likely to reduce return rates and cause injuries to the leg. No effects of geolocators were found on breeding movements or changes in body mass. Among-site variation in geolocator effect size was high, suggesting that local factors were important. Conclusions Negative effects of geolocators occurred only for three of the smallest species in our dataset, but were substantial when present. Future studies could mitigate impacts of tags by reducing protruding parts and minimizing use of additional markers. Investigators could maximize recovery of tags by strategically deploying geolocators on males, previously marked individuals, and successful breeders, though targeting subsets of a population could bias the resulting migratory movement data in some species. Electronic supplementary material The online version of this article (doi:10.1186/s40462-016-0077-6) contains supplementary material, which is available to authorized users.

Seasonal declines in breeding performance are widespread in wild animals, resulting from temporal changes in environmental conditions or from individual variation. Seasonal declines might drive selection for early breeding, with implications for other stages of the annual cycle. Alternatively, selection on the phenology of nonbreeding stages could constrain timing of the breeding season and lead to seasonal changes in reproductive performance. We studied 25 taxa of migratory shorebirds (including five subspecies) at 16 arctic sites in Russia, Alaska, and Canada. We investigated seasonal changes in four reproductive traits, and developed a novel Bayesian risk-partitioning model of daily nest survival to examine seasonal trends in two causes of nest failure. We found strong seasonal declines in reproductive traits for a subset of species. The probability of laying a full four-egg clutch declined by 8–78% in 12 of 25 taxa tested, daily nest survival rates declined by 1–12% in eight of 22 taxa, incubation duration declined by 2.0–2.5% in two of seven taxa, and mean egg volume declined by 5% in one of 15 taxa. Temporal changes were not fully explained by individual variation. Across all species, the proportion of failed nests that were depredated declined over the season from 0.98 to 0.60, while the proportion abandoned increased from 0.01 to 0.35 and drove the seasonal declines in nest survival. An increase in abandonment of late nests is consistent with a life-history tradeoff whereby either adult mortality increased or adults deserted the breeding attempt to maximize adult survival. In turn, seasonal declines in clutch size and incubation duration might be adaptive to hasten hatching of later nests. In other species of shorebirds, we found no seasonal patterns in breeding performance, suggesting that some species are not subject to selective pressure for early breeding. This article is protected by copyright. All rights reserved.

Surveys based on double sampling include a correction for the probability of detection by assuming complete enumeration of birds in an intensively surveyed subsample of plots. To evaluate this assumption, we calculated the probability of detecting active shorebird nests by using information from observers who searched the same plots independently. Our results demonstrate that this probability varies substantially by species and stage of the nesting cycle but less by site or density of nests. Among the species we studied, the estimated single-visit probability of nest detection during the incubation period varied from 0.21 for the White-rumped Sandpiper (Calidris fuscicollis), the most difficult species to detect, to 0.64 for the Western Sandpiper (Calidris mauri), the most easily detected species, with a mean across species of 0.46. We used these detection probabilities to predict the fraction of persistent nests found over repeated nest searches. For a species with the mean value for detectabil...

Conservation of the eastern subspecies of the American oystercatcher (Haematopus palliatus palliatus) is a high priority in the U.S. Shorebird Conservation Plan, but previous population estimates were unreliable, information on distribution and habitat associations during winter was incomplete, and methods for long-term monitoring had not been developed prior to this survey. We completed the aerial survey proposed in the U.S. Shorebird Conservation Plan to determine population size, winter distribution, and habitat associations. We conducted coastal aerial surveys from New Jersey to Texas during November 2002 to February 2003. This area comprised the entire wintering range of the eastern American oystercatcher within the United States. Surveys covered all suitable habitat in the United States for the subspecies, partitioned into 3 survey strata: known roost sites, high-use habitat, and inter-coastal tidal habitat. We determined known roost sites from extensive consultation with biologists and loc...

We have identified a novel omega-hydroxy-alkanedicarboxylic acid, ESP 55016, that favorably alters serum lipid variables in obese female Zucker (fa/fa) rats. ESP 55016 reduced serum non-HDL-cholesterol (non-HDL-C), triglyceride, and nonesterified fatty acid levels while increasing serum HDL-C and beta-hydroxybutyrate levels in a dose-dependent manner. ESP 55016 reduced fasting serum insulin and glucose levels while also suppressing weight gain. In primary rat hepatocytes, ESP 55016 increased the oxidation of [(14)C]palmitate in a dose- and carnitine palmitoyl transferase-I (CPT-I)-dependent manner. Furthermore, in primary rat hepatocytes and in vivo, ESP 55016 inhibited fatty acid and sterol synthesis. The "dual inhibitor" activity of ESP 55016 was unlikely attributable to the activation of the AMP-activated protein kinase (AMPK) pathway because AMPK and acetyl-CoA carboxylase (ACC) phosphorylation states as well as ACC activity were not altered by ESP 55016. Further studies indicated the conversion of ESP 55016 to a CoA derivative in vivo. ESP 55016-CoA markedly inhibited the activity of partially purified ACC. The activity of partially purified HMG-CoA reductase was not altered by the xenobiotic-CoA. These data suggest that ESP 55016-CoA favorably alters lipid metabolism in a model of diabetic dyslipidemia in part by initially inhibiting fatty acid and sterol synthesis plus enhancing the oxidation of fatty acids through the ACC/malonyl-CoA/CPT-I regulatory axis.

Central core disease (CCD) is a congenital myopathy due to dominant mutations in the skeletal muscle ryanodine receptor gene (RYR1). The authors report three patients from two consanguineous families with symptoms of a congenital myopathy, cores on muscle biopsy, and confirmed linkage to the RYR1 locus. Molecular genetic studies in one family identified a V4849I homozygous missense mutation in the RYR1 gene. This report suggests a congenital myopathy associated with recessive RYR1 mutations.

Clostridium difficile infection has emerged as a growing worldwide health problem. The colitis of Clostridium difficile infection results from the synergistic action of C. difficile secreted toxins A and B upon the colon mucosa. A human monoclonal IgG anti-toxin has demonstrated the ability in combination therapy to reduce mortality in C. difficile challenged hamsters. This antibody is currently in a clinical trial for the treatment of human Clostridium difficile infection. More than one group of investigators has considered using polyclonal bovine colostral antibodies to toxins A and B as an oral passive immunization. A significant proportion of the healthy human population possesses polyclonal antibodies to the Clostridium difficile toxins. We have demonstrated that polyclonal IgA derived from the pooled plasma of healthy donors possesses specificity to toxins A and B and can neutralize these toxins in a cell-based assay. This suggests that secretory IgA prepared from such pooled plasma IgA may be able to be used as an oral treatment for Clostridium difficile infection.

Measuring the success of wetland restoration efforts requires an assessment of the wetland plant community as it changes following restoration. But analyses of restored wetlands often include plant community data from only one time period. We studied the development of plant communities at 13 restored marshes in northern New York for 4 years, including 1 year prior to restoration and 3 years afterwards. Restored wetlands ranged in size from 0.23 to 1.70 ha. Four reference wetlands of similar basin morphology, soil type, and size (0.29-0.48 ha) that occurred naturally in the same area were studied as comparisons. Dike construction to restore hydrology disturbed the existing vegetation in some parts of the restored sites, and vegetation was monitored in both disturbed and undisturbed areas. Undisturbed areas within the restored sites, which were dominated by upland field grasses before restoration, developed wetland plant communities with lower wetland index values but comparable numbers of wetland plant species than the reference wetlands, and they lagged behind the reference sites in terms of total wetland plant cover. There were significantly more plant species valuable as food sources for wetland birds, and a significantly higher percent cover of these species, at the undisturbed areas of the restored sites than at the reference wetlands. Areas of the restored sites that were disturbed by dike construction, however, often developed dense, monospecific cattail stands. In general, the plant communities at restored sites became increasingly similar to those at the reference wetlands over time, but higher numbers of herbaceous plants developed at the restored sites, including food plants for waterfowl, rails, and songbirds. Differences in shrub cover will probably lessen as natural recolonization increases shrub cover at the restored sites. Natural recolonization appears to be an effective technique for restoring wetlands on abandoned agricultural fields with established plant cover, but it is less successful in areas where soil has been exposed by construction activity.

Selection of sites for wetland restoration requires analysis of probable success at recreating diverse natural vegetation. We studied the seed banks and the remnant vegetation at restoration sites to determine their degree of similarity to the vegetation that developed following restoration of wetland hydrology. The study sites had been used for forage crops and pasture following long-term drainage. The seed bank was a very poor predictor of plant species abundances following restoration. Similarity between remnant vegetation and restored vegetation was consistently higher than similarity values using seed banks at both restored and natural wetlands. Our results suggest that seed-bank analysis is an inefficient technique for predicting restored vegetation in sites with prolonged disturbance, and that analysis of remnant vegetation on the sites is probably more useful. However, results would probably differ at sites with tile drainage that have limited remnant vegetation or created wetlands with bare soil where seed germination would play a greater role in revegetation. In addition, seed-bank studies are important to determine if aggressive invasive species are present at potential restoration sites.Key words: seed banks, wetlands, restoration, marshes, vegetation.

Wetlands are being restored throughout the United States in an effort to replace habitat functions lost following drainage. We studied the macroinvertebrate communities that developed in wetlands restored by the U.S. Fish and Wildlife Service and compared them to those occurring at natural wetlands in the same area. During the 3 yr of the study, most taxa found at the natural sites could also be found in similar numbers at the restored sites. Insects with aerial dispersal capability rapidly colonized the restored habitats, but some less mobile forms (non-insects and some hemipterans) either colonized more slowly or not at all. We analyzed the effects of experimental techniques for site preparation that were applied before restoration of hydrology to determine if they influenced macroinvertebrate recolonization. Transplantation of remnant wetland soil, which resulted in faster and more prolific plant growth, significantly increased overall macroinvertebrate numbers, and significantly increased the abundance of 10 specific taxonomic groups. The use of this technique, along with possible inoculation of some less mobile taxa, could improve efforts to reestablish natural macroinvertebrate communities to newly restored wetland habitats.

Restoration of drained wetlands requires the re-establishment of a native wetland plant community. This can be difficult in areas where long-term drainage has eliminated wetland vegetation and significantly reduced the number of viable wetland plant seeds in the seed bank. This study of U.S. Fish and Wildlife Service wetland restoration sites in northern New York examines the effectiveness of transplanting wetland soil from small remnant wetlands in the drainage ditches to the area that becomes shallow marsh following reflooding. The results of two experiments are reported, including a small-scale study of transplantation techniques using small plots with treatments and controls established by hand, and a large-scale application of soil transplantation and site-preparation techniques using heavy equipment to establish large plots across entire wetland basins. In the small-scale study, the transplant plots had significantly lower wetland index values, indicating greater dominance of wetland plants, after one growing season but not after two. Transplant plots also had more wetland plant species and more wetland plant cover than natural control plots, and these differences persisted through the second growing season. Litter removal and soil disturbance also lowered the wetland index values and increased wetland plant species number and cover, but only for the first growing season. In the large-scale study, soil transplantation significantly increased both the number of species and the amount of cover of wetland plants and of plants valuable as wildlife food sources. Mowing and plowing treatments increased wetland plant establishment, but much less than soil transplantation, and plowing significantly increased the establishment of cattail (Typha spp.), an undesirable invasive species in small wildlife marshes. Soil transplantation should be a particularly effective technique for improving wetland plant establishment and limiting cattail encroachment in areas disturbed by dike construction.

On the Arctic Coastal Plain of the National Petroleum Reserve-Alaska (NPR-A), the Teshekpuk Lake Special Area (TLSA) was recognized to protect outstanding wildlife values. Although information has accumulated on the TLSA's value to caribou and waterfowl, its importance to breeding shorebirds remains largely unquantified. Therefore, we undertook a broad-scale ground study to estimate the population size and density of shorebirds breeding in the TLSA. From a series of plot surveys conducted from 2006 to 2008, we estimated a detection-adjusted total breeding population of more than 573 000 shorebirds and an overall density of 126 shorebirds/km 2 . Most shorebird species had their greatest densities on the Outer Coastal Plain or had approximately equal densities on Outer and Inner Coastal Plains; only two species had their greatest densities on the Inner Coastal Plain. The greatest densities of breeding shorebirds occurred immediately around Teshekpuk Lake. The TLSA supported more than 10% of the biogeographic populations of black-bellied plover (Pluvialis squatarola), semipalmated sandpiper (Calidris pusilla), and dunlin (C. alpina). Breeding shorebird density in the TLSA is one of the highest in the NPR-A, on Alaska's North Slope, and throughout the circumpolar Arctic. Our results, coupled with previous information on waterfowl and caribou, indicate that the area around Teshekpuk Lake and the recognized goose molting area northeast of the lake should be protected from oil and gas development.

Peptide nucleic acids (PNA) are oligodeoxynucleotide (ODN) analogs in which the sugar phosphate backbone of the ODN has been replaced by one derived from units of N-ethylaminoglycine. PNAs recognize DNA and RNA in a sequence specific manner and form complexes that can be characterized by biophysical methods. The binding motif is context dependent; homopyrimidine PNAs combine with complementary polypurine targets to form stoichiometric 2:1 complexes, whereas PNAs containing both purine and pyrimidine bases afford a 1:1 heteroduplex with mis-match sensitivity comparable to that found in dsDNA. These complexes mediate the antigene and antisense effects of PNAs via the steric blockade of enzyme complexes responsible for DNA transcription, cDNA synthesis, and RNA translation. PNAs, like ODNs, are taken up by cells via endocytosis leading to their entrapment within intracytoplasmic vesicles. Under circumstances where agent delivery is solved by cell microinjection, PNAs can effect selective inhibition of endogenous and exogenous genes. The impact of biophysical parameters on the biological assessment of PNAs as antisense inhibitors of gene expression is presented and discussed. © 1995 Wiley-Liss, Inc.

Peptide nucleic acids (PNA) incorporating nucleic acid bases into an achiral polyamide backbone bind to DNA in a sequence-dependent manner. The structure of a PNA-ribonucleic acid (RNA) complex was determined with nuclear magnetic resonance methods. A hexameric PNA formed a 1:1 complex with a complementary RNA that is an antiparallel, right-handed double helix with Watson-Crick base pairing similar to the "A" form structure of RNA duplexes. The achiral PNA backbone assumed a distinct conformation upon binding that differed from previously proposed models and provides a basis for further structure-based design of antisense agents.

Nest predation may influence population dynamics of birds on the Arctic Coastal Plain (ACP) of Alaska, USA. Anthropogenic development on the ACP is increasing, which may attract nest predators by providing artificial sources of food, perches, den sites, and nest sites. Enhanced populations or concentrations of human-subsidized predators may reduce nest survival for tundra-nesting birds. In this study, we tested the hypothesis that nest survival decreases in proximity to human infrastructure. We monitored 1257 nests of 13 shorebird species and 619 nests of four passerine species at seven sites on the ACP from 2002 to 2005. Study sites were chosen to represent a range of distances to infrastructure from 100 m to 80 km. We used Cox proportional hazards regression models to evaluate the effects of background (i.e., natural) factors and infrastructure on nest survival. We documented high spatial and temporal variability in nest survival, and site and year were both included in the best background model. We did not detect an effect of human infrastructure on nest survival for shorebirds as a group. In contrast, we found evidence that risk of predation for passerine nests increased within 5 km of infrastructure. This finding provides quantitative evidence of a relationship between infrastructure and nest survival for breeding passerines on the ACP. A posteriori finer-scale analyses (within oil field sites and individual species) suggested that Red and Red-necked Phalaropes combined (Phalaropus fulicarius, P. lobatus) had lower productivity closer to infrastructure and in areas with higher abundance of subsidized predators. However, we did not detect such a relationship between infrastructure and nest survival for Semipalmated and Pectoral Sandpipers (Calidris pusilla, C. melanotos), the two most abundant shorebirds. High variability in environmental conditions, nest survival, and predator numbers between sites and years may have contributed to these inconsistent results. We recommend targeted management actions to minimize anthropogenic effects and suggest new research needed on this issue as expanding development is planned for the ACP of Alaska. In particular, we recommend research on demography of key predators and their importance with respect to nest survival, and experimental studies that better address challenges posed by high natural variability.

The effects of purified prolactins isolated from frogs (fPRL; Rana catesbeiana) and newts (nPRL; Cynops pyrrhogaster) were compared with those of ovine prolactin (oPRL) and thyrotropin releasing hormone (TRH) in the eft (Notophthalmus viridescens) skin transepithelial potential (TEP) bioassay. At total doses as low as 0.4 micrograms/animal, both fPRL and nPRL were as effective as oPRL in reducing eft skin TEP. By contrast, TRH at total doses as high as 400 micrograms/animal was ineffective in altering eft skin TEP. These data provide the first direct evidence that amphibian PRLs can exert significant physiological control over salamandrid integumental sodium transport.

The bifunctional intercalator Ditercalinium (NSC 335153) demonstrates an anti-tumoral cytotoxicity markedly different from other intercalating agents. A delayed toxicity is observed in eucaryotic cells, both in vitro and in vivo , at drug concentrations far below those required to observe immediate toxic effects. Fluorescence microscopy demonstrates that Ditercalinium and the mit-ochondrial-staining fluorophore DiOC 2 (5) are concentrated in the same cellular organelles of L1210 cells. Electron microscopy of Ditercalinium-treated cells reveals extensive and progressive swelling of mitochondria, with no other ultrastructural changes observed. Ditercalinium uptake and toxicity are in part related to mitochondrial membrane potential. However, drug accumulation itself does not immediately alter the mitochondrial membrane potential. Cellular ATP pool levels and the rate of respiration fall progressively after drug treatment. Nucleotide pools in DC3F cells, measured between drug treatment and death, show marked drops in pyrimidine levels while purine nucleotide levels decline more slowly. Addition of uridine or cytidine partially rescues Ditercalinium-treated cells, while toxicity is increased in the presence of 2-deoxyglucose. The combined evidence indicates that the toxicity of Ditercalinium to murine leukemia cells (L1210) and Chinese Hamster lung cells (DC3F) is due to disruption of mitochondrial function.

The authors wish to add the following to the acknowledgments of [1]: “The authors acknowledge the contribution of Dr. Ricky Malhotra to our research efforts. Dr. Malhotra introduced the cell culture techniques into our lab and helped to establish the cell based assay. He also helped to prepare Figure 4.”

Individuals with the same genetic disorder often show remarkable differences in clinical severity, a finding generally attributed to the genetic background. We identified two patients with genetically proven Emery-Dreifuss muscular dystrophy (EDMD) who followed an unusual course and had uncommon clinicopathological findings. We hypothesized digenic inheritance and looked for additional molecular explanations. Mutations in additional separate genes were identified in both patients. The first patient was a member of a family with molecularly proven X-linked EDMD. However, the clinical features were unusually severe for this condition in the propositus: he presented at 2.5 years with severe proximal weakness and markedly elevated serum creatine kinase. Muscle weakness rapidly progressed, leading to loss of independent ambulation by the age of 12. In addition, the patient developed cardiac conduction system disease requiring pacing at the age of 11 and severe dilated cardiomyopathy in the early teens. Despite pacing, he had several syncopal episodes attributed to ventricular dysrhythmias. As these resemble the cardiac features of patients with the autosomal dominant variant of EDMD, we examined the lamin A/C gene, identifying a de-novo mutation in the propositus. The second patient had a cardioskeletal myopathy, similar to his mother who had died more than 20 years previously. Because of the dominant family history, a laminopathy was suspected and a mutation in exon 11 of the LMNA gene was identified. This mutation, however, was not present in his mother, but instead, surprisingly, was identified in his virtually asymptomatic father. Unusual accumulations of desmin found in the cardiac muscle of the propositus prompted us to examine the desmin gene in this patient, and in so doing, we identified a desmin mutation, in addition to the LMNA mutation in the propositus. These cases suggest that separate mutations in related proteins that are believed to interact, or that represent different parts of a presumed functional pathway, may synergistically contribute to disease severity in autosomal dominant EDMD. Furthermore, digenic inheritance may well contribute to the clinical severity of many other neuromuscular disorders.

Background: Congenital muscular dystrophies (CMD) are autosomal recessive disorders that present within the first 6 months of life with hypotonia and a dystrophic muscle biopsy. CNS involvement is present in some forms. The fukutin-related protein gene ( FKRP ) is mutated in a severe form of CMD (MDC1C) and a milder limb girdle dystrophy (LGMD2I). Both forms have secondary deficiencies of laminin α2 and α-dystroglycan immunostaining. Structural brain involvement has not been observed in patients with FKRP gene mutations. Methods: The authors studied two unrelated patients who had a pattern of muscle involvement identical to MDC1C, mental retardation, and cerebellar cysts on cranial MRI. The FKRP gene was analyzed along with the skeletal muscle expression of laminin α2 and α-dystroglycan. Results: The muscle biopsy of both patients showed severe dystrophic findings, a reduction in laminin α2, and profound depletion of α-dystroglycan. Both patients had homozygous FKRP gene mutations not previously reported (C663A [Ser221Arg] and C981A [Pro315Thr]). Conclusions: Mutations within the FKRP gene can result in CMD associated with mental retardation and cerebellar cysts. This adds structural brain defects to the already wide spectrum of abnormalities caused by FKRP mutations. The severe depletion of α-dystroglycan expression suggests that FKRP is involved in the processing of α-dystroglycan.

Despite an increase in conservation efforts for shorebirds, there are widespread declines of many species of North American shorebirds. We wanted to know whether these declines would be exacerbated by climate change, and whether relatively secure species might become at-risk species. Virtually all of the shorebird species breeding in the USA and Canada are migratory, which means climate change could affect extinction risk via changes on the breeding, wintering, and/or migratory refueling grounds, and that ecological synchronicities could be disrupted at multiple sites. To predict the effects of climate change on shorebird extinction risks, we created a categorical risk model complementary to that used by Partners-in-Flight and the U.S. Shorebird Conservation Plan. The model is based on anticipated changes in breeding, migration, and wintering habitat, degree of dependence on ecological synchronicities, migration distance, and degree of specialization on breeding, migration, or wintering habitat. We evaluated 49 species, and for 3 species we evaluated 2 distinct populations each, and found that 47 (90%) taxa are predicted to experience an increase in risk of extinction. No species was reclassified into a lower-risk category, although 6 species had at least one risk factor decrease in association with climate change. The number of species that changed risk categories in our assessment is sensitive to how much of an effect of climate change is required to cause the shift, but even at its least sensitive, 20 species were at the highest risk category for extinction. Based on our results it appears that shorebirds are likely to be highly vulnerable to climate change. Finally, we discuss both how our approach can be integrated with existing risk assessments and potential future directions for predicting change in extinction risk due to climate change.

The Arctic Coastal Plain (ACP) of Alaska is an important region for millions of migrating and nesting shorebirds. However, this region is threatened by climate change and increased human development (e.g., oil and gas production) that have the potential to greatly impact shorebird populations and breeding habitat in the near future. Because historic data on shorebird distributions in the ACP are very coarse and incomplete, we sought to develop detailed, contemporary distribution maps so that the potential impacts of climate-mediated changes and development could be ascertained. To do this, we developed and mapped habitat suitability indices for eight species of shorebirds (Black-bellied Plover [Pluvialis squatarola], American Golden-Plover [Pluvialis dominica], Semipalmated Sandpiper [Calidris pusilla], Pectoral Sandpiper [Calidris melanotos], Dunlin [Calidris alpina], Long-billed Dowitcher [Limnodromus scolopaceus], Red-necked Phalarope [Phalaropus lobatus], and Red Phalarope [Phalaropus fulicarius]) that commonly breed within the ACP of Alaska. These habitat suitability models were based on 767 plots surveyed during nine years between 1998 and 2008 (surveys were not conducted in 2003 and 2005), using single-visit rapid area searches during territory establishment and incubation (8 June–1 July). Species-specific habitat suitability indices were developed and mapped using presence-only modeling techniques (partitioned Mahalanobis distance) and landscape environmental variables. For most species, habitat suitability increased at lower elevations (i.e., near the coast and river deltas) and decreased within upland habitats. Accuracy of models was high for all species, ranging from 65–98%. Our models predicted that the largest fraction of suitable habitat for the majority of species occurred within the National Petroleum Reserve-Alaska, with highly suitable habitat also occurring within coastal areas of the Arctic National Wildlife Refuge west to Prudhoe Bay.

The antisense activity and gene specificity of two classes of oligonucleotides (ONs) were directly compared in a highly controlled assay. One class of ONs has been proposed to act by targeting the degradation of specific RNAs through an RNase H-mediated mechanism and consists of C-5 propynyl pyrimidine phosphorothioate ONs (propyne-S-ON). The second class of antisense agents has been proposed to function by sterically blocking target RNA formation, transport or translation and includes sugar modified (2'-O-allyl) ONs and peptide nucleic acids (PNAs). Using a CV-1 cell based microinjection assay, we targeted antisense agents representing both classes to various cloned sequences localized within the SV40 large T antigen RNA. We determined the propyne-S-ON was the most potent and gene-specific agent of the two classes which likely reflected its ability to allow RNase H cleavage of its target. The PNA oligomer inhibited T Ag expression via an antisense mechanism, but was less effective than the propyne-S-ON; the lack of potency may have been due in part to the PNAs slow kinetics of RNA association. Interestingly, unlike the 2'-O-allyl ON, the antisense activity of the PNA was not restricted to the 5' untranslated region of the T Ag RNA. Based on these findings we conclude that PNAs could be effective antisense agents with additional chemical modification that will lead to more rapid association with their RNA target.

SHOREBIRDS ARE AMONG the most highly migratory creatures on earth. Both the study of their ecology and ongoing efforts to conserve their populations must reflect this central aspect of their biology. Many species of shorebirds use migration and staging sites scattered throughout the hemisphere to complete their annual migrations between breeding areas and nonbreeding habitats (Morrison 1984). The vast distances between habitats they use pose significant challenges for studying their migration ecology. At the same time, the large number of political boundaries shorebirds cross during their epic migrations create parallel challenges for organizations working on their manage

Restoration of drained wetlands may contribute significantly to conservation of habitats for wetland birds, and state and federal agencies throughout the country rely on restoration and creation of wetlands to mitigate habitat losses to development. However, it is unclear if restored systems replace the habitat functions of natural wetlands, and few direct comparisons of multiple sites have been made. Three years after restoration, we compared the relative abundance and density of birds using 18 restored wetlands and 8 natura wetlands located in northern New York. Birds were classified as wetland dependent, wetland associated, or nonwetland. Abundances of species and of individuals in all 3 groups did not differ (P > 0.05) between restored and natural wetlands in any year. Densities of species in all 3 groups were consistently but not significantly lower at restored sites. Densities of individuals in the wetland-associated category and nonwetland category were significantly lower at restored sites for the first years following restoration. Bird communities were significantly less similar between restored and natural sites than among restored sites. However, many of these differences may not persist following natural successional development of the restored sites. The long-term persistence of appropriate plant communities will determine whether or not restored sites provide bird habitat comparable to natural wetlands. The restoration program successfully increased the amount of bird habitat available in the region. However, hectare-for-hectare, the restored wetland sites did not replace the habitat functions of natural wetlands during the time period of this study.

1. The activities of the three water-pumping segments of Chaetopterus variopedatus are correlated in detail with the fluctuations in water flow through the tube-house. 2. The qualitative performance and design features of the worm's pumping mechanism are compared to those of mechanical reciprocating pumps. 3. Quantitative data on volume flow rate, stroke rate, discharge pressure, and oxygen consumption yield estimates of power output (1.5 X 10(-5) Joules/sec) and aerobic efficiency (0.5%). 4. In its natural habitat, Chaetopterus does no lifting work, but rather functions solely as a transfer pump. 5. Calculations show that, of the work accomplished by Chaetopterus during pumping, 95% is devoted to overcoming inertial resistance.

The developing chick embryo exhibits a regular pattern of accumulation and reabsorption of fluid in its extraembryonic compartments. Fluid volume (measured by dye dilution) peaks at Day 14 in both the allantois (12.4 ml) and the amnion (5.1 ml). The standard experimental procedure of removing 2 ml of albumen at 33–36 hr of incubation does not alter this pattern, but leads to a maximum decrease in fluid volume of ca. 1 ml in both amniotic and allantoic compartments. Although [Na] and [Cl] remain essentially constant in the serum, they steadily decrease in the allantois (remaining substantially below serum levels). In the amnion, [Cl] is maintained above that of serum, whereas [Na] falls below serum [Na] by Day 14. In the Day 12 (stage 38) embryo, hypophysectomy (HX) causes a substantial increase in the allantoic fluid volume and [Na] and [Cl], thus resulting in a 166% increase in total Na and Cl over that of sham-operated embryos. By contrast, HX did not alter amniotic fluid volume, although it did decrease [Na] and to a lesser degree, [Cl]. Serum [Na], but not [Cl], was reduced by HX. HX abolished the normally steep ionic gradients maintained between the allantois and both serum and amnion. Thus, the most dramatic effects of HX at Day 12 are on the allantois, which accumulates both Na and Cl at the expense of the amnion and serum. This suggests that pituitary hormones may normally act by Day 12 to reduce urinary volume and electrolyte excretion and/or to increase fluid and electrolyte reabsorption from the allantois.

The major chelipeds of five species of decapod crustaceans were studied with reference to lever system mechanical advantage, pattern of occlusive geometry, and force/pressure developed during cheliped closure by intact animals. Every cheliped type was found to possess a linear array of two to four distinctive regions of occlusion. The factors responsible for the differences in occlusive design are discussed. It is suggested that crustacean major chelipeds must be regarded as regionally-specialized, multifunctional appendages.

1. 1. Wet and dry weights were determined for Rana sylvatica larvae (Taylor-Kollros stages II-XXV). 2. 2. Wet weight and absolute water content increase steadily through stages XVII–XVIII and then rapidly decrease. 3. 3. Proportional water content (water:dry weight) decreases from a high level of 20:1 to a low level of 6.3:1. 4. 4. Although 50% of the absolute water content is lost between stages XVII and XXV, the apparent drop is only 2.2% when water is expressed as a percent of total body weight. 5. 5. These data demonstrate that the comparison of water in percent-of-body-weight terms can potentially lead to erroneou conclusions.

Hypophysectomy significantly reduced serum sodium levels inDesmognathus fuscus andD. monticola. Prolactin, corticosterone or aldosterone replacement failed to restore serum sodium to control levels. Hypophysectomy also led to decreases in in vitro integumental potential difference and shortcircuit current, which were not restored to control levels by prolactin or corticosterone. Thyroidectomy significantly reduced the level of serum sodium inD. monticola, but it increased in vitro potential difference and short-circuit current. Thyroxine treatment of either hypophysectomized or thyroidectomizedD. monticola completely restored serum sodium, potential difference and short-circuite current to control levels.

The tube-cleaning behaviour of Chaetopterus variopedatus was investigated utilizing a glass observation chamber and water-pressure recording system. Intake of particulate material into the tube-house resulted in one or more of the following responses: (1) cessation of water-flow; (2) increased water-flow in the normal direction; (3) very short but intense bursts of reversed water-flow; and (4) long duration, high velocity, reversed water-flow. The behavioural events underlying the various flow-patterns are described. The functional effectiveness and neural control of the different cleaning responses are discussed.

1. 1. Sodium fluxes in Notophthalmus viridescens were found to be higher than those of any amphibian examined to date. 2. 2. The total sodium loss from unfed animals was 49.4 μ-equiv/g/day, or ca . 102% of total body sodium/day. 3. 3. Integumental loss accounted for 68% of the total; urinary loss, 32%. 4. 4. Integumental sodium uptake exhibited saturation kinetics, with a J max = 234 μ-equiv/g/day and a k m = 2.1 m-equiv/l. 5. 5. The high capacity of the transport system allows losses to be replaced at external sodium concentrations approaching 0.1 m-equiv/l.

Integumental transepithelial potential (TEP) was measured by both in vivo and in vitro (Ussing chamber) techniques in the same adult terrestrial-phase California newts (Taricha torosa). In both types of preparation, TEP showed a logarithmic relation to external sodium (as Na2SO4) concentrations between 0.1 and 10 meq/liter, with in vivo values exceeding in vitro values at all points. KM was ca. 1 and 5 meq/liter for the in vivo and in vitro preparations, respectively. When terrestrial-phase newts were treated with prolactin (PRL; 50 mIU/g/day), in vivo TEP declined significantly within 3 days. In vivo TEP versus [Na+]ext curves of recently collected aquatic-phase newts were found to be not significantly different from those of PRL-treated terrestrial-phase animals. Current/voltage (I/V) plots likewise showed that skin from aquatic-phase and PRL-treated terrestrial-phase newts was electrophysiologically alike. Estimates and calculations based on the I/V relationship suggest that PRL acts primarily to increase the epithelial electrical resistance in the transcellular pathway, with no effect on the electromotive force of the sodium pump.

1. The skeletomusculature of the water-pumping segments of Chaetopterus variopedatus was examined in detail and the behavior of the segments during active water-propulsion was analyzed using cinemaphotographic techniques. 2. The musculature of the pumping segments consists largely of thin sheets of radial, transverse, and circular fibers, located immediately beneath the thin integument. Exceptions to this are the numerous isolated fibers running axially across the coelomic cavity of the parapodial rim and the major remotor muscles which originate in the neuropodial "sucker" of the adjacent posterior segment. 3. The motion of the pump segments is basically reciprocative, with the axial displacement during power and recovery strokes approximating a sine function. Centrifugal radial displacements (during the power stroke) effectively seal the lumen of the tube; centripital radial displacements (during the recovery stroke) allow water from the inlet side of the tube to by-pass the pump segment. 4. Comparison of the muscle anatomy with the displacements and shape changes which take place during water-propulsion permitted analysis of the muscle actions during the pump cycle. It is concluded that: (a) both axial and radial displacements during the power stroke are caused by a single set of muscles (remotors); (b) maintenance of the extended-disk configuration is consequent upon coelomic fluid being forced into the parapodial rim, with the axial muscle fibers acting as guy-wires to resist overexpansion; (c) most of the sheet-like muscle groups contract during the recovery stroke, thereby causing the segment to assume a nearly spherical configuration; and (d) two sets of muscles (promotors, oblique parapodial) are responsible for the axial displacement during recovery. 5. The water-pumping mechanism of Chaetopterus is compared to those of the majority of worms, which are based on persistaltic or undulatory movements.

In vivo integumental transepithelial potential (TEP) in the Eastern red-spotted newt (Notophthalmus viridescens) increases linearly with external [Na+] from 0.1 to 10 mM and is anion independent. Both integumental TEP and osmotic permeability are higher in laboratory-conditioned (LC, terrestrial) than in breeding-condition (BC, aquatic) newts at temperatures of 5-25 degrees. Prolactin (PRL) treatment of LC newts decreased both TEP and rate of water uptake. Arginine vasotocin (AVT) treatment resulted in a substantial increase in water uptake in LC newts, while little or no AVT response was seen in PRL-treated or BC newts. Hypophysectomy (HX) or ergocryptine treatment increased TEP in BC newts, whereas HX + PRL maintained TEP at control levels. Although ergocryptine and HX were without effect on water uptake in BC newts kept at 5 degrees for 9 days, HX + ACTH increased water uptake. HX produced a substantial fall in serum [Na+] in BC newts, while either PRL or ACTH replacement elevated serum [Na+]. Combined ACTH and PRL treatment returned serum [Na+] to control levels. These data suggest that high endogenous prolactin plays a significant role in maintaining serum [Na+] and integumental permeability and transport characteristics in breeding-condition N. viridescens. Although PRL and ACTH are both sodium retaining in the aquatic breeding stage, these two hormones promote opposite effects on the integument; PRL decreases both water uptake and integumental TEP, whereas ACTH (presumably acting through the adrenals) increases water uptake and possibly TEP.

The cichlid fish tilapia (Oreochromis mossambicus) produces two forms of prolactin (tPRL177 and tPRL188) at equal rates. The primary sequences of this prolactin pair share only 69% identity. In these experiments, the whole-animal transepithelial potential (TEP) in the eft stage of the red-spotted newt (Notophthalmus viridescens) was measured in response to two injections totaling about 2 μg of tPRL177, tPRL188, ovine PRL, or tilapia growth hormone (tGH), or distilled water (5 μL/injection). This investigation was undertaken in order to locate prolactin receptors which discriminate between the two molecular forms of tilapia prolactin. The salamandrid integumental bioassay for prolactin was found to respond to tPRL177 as it does to ovine PRL. The more mainline tPRL188 was without effect at this dose and thus behaved more similarly to growth hormone (tilapia and ungulate) in this bioassay. The suspected magnitude of differences in the molecular surface characteristics between the two prolactins seem to be adequate to allow the binding of tPRL177 and to hinder the binding of tPRL188 to prolactin specific receptors in eft epithelial tissues.

1. In Chaetopterus gradually adapted to lowered salinities, coelomic fluid osmolarity and sodium and chloride concentrations conform to ambient seawater at salinities from 1100 to 630 mOsm.2. Experimental animals were unable to tolerate salinities below 630 mOsm for extended periods of time.3. Worms transferred directly to hypoosmotic stress solutions down to 681.8 mOsm gained weight (volume) rapidly, reaching a maximum in approximately 1.5 hours. At this point, the coelomic fluid was isoosmotic with the external medium. After 1.5 hours, there followed a decrease in volume, which as shown in one experiment, culminated in a return to initial volume values.4. Transfers back to full-strength seawater indicate that salt efflux as well as water influx occurred.5. It is concluded that Chaetopterus is a volume-regulating osmoconformer over its viable range of salinities.6. Current theories of the mechanism of isoosmotic volume-regulation are discussed and a mechanically linked "volumestat" model is proposed.7. T...

The wall of the tube 'house' constructed by the polychaetc, Chaelopterus variopedatus, was examined by scanning and transmission electron microscopy and polarizing and phase-contrast light microscopy. The tube wall consists of alternating plies of aligned protein fibres imbedded in an unstructured matrix. The protein fibres range in diameter from 50-400 mmu and have an axial periodicity of about 641 A. The relative proportion of fibres to matrix, the total number of plies, and the number of fibres per ply vary throughout the tube.