bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Analysis of the Shaft Motion in the Journal Bearing of a Gear Pump
Authors: Castilla R. , Gutes M. , Gamez-Montero P. J. , Codina E.
Published: October 2009

This paper describes a numerical analysis of the dynamics of the shaft in the journal bearing of a gear pump. The modulus and direction of the load is a function of the relative position of the gears, causing a precession motion around an equilibrium position. The mean load is the function of the working pressure of the gear pump. The numerical analysis presented in this paper combines the equation of motion of the journal-gear set, based on the linearization of the fluid film load, with calculation of the load due to the pressure distribution on the gears. The damping and stiffness coefficients for the motion equation are calculated with the distributions around the shaft of the pressure and its derivatives. These distributions are calculated from the Reynolds equations using an in-house 2D finite element code with quadrangular elements; the equation of motion is solved with a fifth-order Runge–Kutta scheme. The results provide the stabilized position of the shaft for certain conditions, and allow limitation of the working pressure and the angular velocity of the pump in order to minimize, or to avoid, metal-metal contact and consequent wear of material. The results are compared with experiments and previously reported numerical results.
Mining Process and Product Information From Pressure Fluctuations Within a Fuel Particle Coater
Authors: Marshall Douglas W. , Barnes Charles M.
Published: October 2009

The next generation nuclear power/advanced gas reactor (NGNP/AGR) fuel development and qualification program included the design, installation, and testing of a 6-in. diameter nuclear fuel particle coater to demonstrate quality tri-structural isotropic (TRISO) fuel production on a small industrial scale. Scale-up from the laboratory-scale coater faced challenges associated with an increase in the kernel charge mass, kernel diameter, and a redesign of the gas distributor to achieve adequate fluidization throughout the deposition of the four TRISO coating layers. TRISO coatings are applied at very high temperatures in atmospheres of dense particulate clouds, corrosive gases, and hydrogen concentrations over 45% by volume. The severe environment, stringent product and process requirements, and the fragility of partially-formed coatings limit the insertion of probes or instruments into the coater vessel during operation. Pressure instrumentation were installed on the gas inlet line and exhaust line of the 6-in. coater to monitor the bed differential pressure and internal pressure fluctuations emanating from the fuel bed as a result of bed and gas “bubble” movements. These instruments are external to the particle bed and provide a glimpse into the dynamics of fuel particle bed during the coating process and data that could be used to help ascertain the adequacy of fluidization and, potentially, the dominant fluidization regimes. Pressure fluctuation and differential pressure data are not presently useful as process control instruments, but data suggest a link between the pressure signal structure and some measurable product attributes that could be exploited to get an early estimate of the attribute values.
Response to Comment on “The
Arabidopsis
Circadian Clock Incorporates a cADPR-Based Feedback Loop”
Authors: Dodd Antony N. , Gardner Michael J. , Hotta Carlos T. , Hubbard Katharine E. , Dalchau Neil , Robertson Fiona C. , Love John , Sanders Dale , Webb Alex A. R.
Published: October 2009

Xu
et al
. were unable to measure circadian oscillations of cyclic adenosine diphosphate ribose (cADPR). Their experiments showing very low concentrations of cADPR lack appropriate controls, which suggests that technical limitations might explain their negative result. Xu
et al
. also report that chemically induced ADP ribosyl cyclase did not alter clock function, which exactly replicates our findings.
The Shape and Surface Variation of 2 Pallas from the Hubble Space Telescope
Authors: Schmidt B. E. , Thomas P. C. , Bauer J. M. , Li J.-Y. , McFadden L. A. , Mutchler M. J. , Radcliffe S. C. , Rivkin A. S. , Russell C. T. , Parker J. Wm. , Stern S. A.
Published: October 2009

Protoplanet 2 Pallas

With a diameter of 265 kilometers, 2 Pallas is one of the largest bodies in the main asteroid belt. Now

Schmidt
et al.

(p.
275
) have characterized its surface and shape using images from the Hubble Space Telescope. Color variations and topography were revealed that are possibly linked to the asteroid's thermal evolution and to the formation of its orbital family—the population of asteroids that share the same properties as 2 Pallas and are thought to be the fragments of a collision. In particular, a large-impact crater was observed that could represent the source of the Pallas family. 2 Pallas represents the third intact protoplanet in the main asteroid belt, joining asteroids 1 Ceres and 4 Vesta.
Aorta's Cardinal Secret
Authors: Benedito Rui , Adams Ralf H.
Published: October 2009

An unexpected process for forming arteries and veins that involves cell segregation is discovered in zebrafish.
On the Mammalian Ear
Authors: Martin Thomas , Ruf Irina
Published: October 2009

Embryonic development played a key role in the evolution of the mammalian ear.
The Art of Translation
Authors: Alberts Bruce
Published: October 2009

This week marks the launch of the new AAAS journal
Science Translational Medicine
. I am very pleased that we were able to recruit Elias A. Zerhouni, the distinguished former director of the U.S. National Institutes of Health, to be its chief scientific adviser, and Katrina L. Kelner, until recently the Deputy Editor for Biological Sciences at
Science
, to be its editor. As Zerhouni writes in his editorial, the goals of this journal, and of translational medicine more broadly, are to speed the rate at which the astounding recent advances in our basic understanding of biological mechanisms are exploited for preventing and treating human disease.
*
Digital Imaging, Communication Advances Honored
Authors: Cho Adrian
Published: October 2009

This year's Nobel Prize in physics was awarded to three scientists whose discoveries made the instantaneous dissemination of information and images possible.
Francis Collins: Looking Beyond the Funding Deluge
Authors: Kaiser Jocelyn
Published: October 2009

U.S. National Institutes of Health (NIH) Director Francis Collins wound up his sixth week on the job with a splash last week, hosting a visit from President Barack Obama.
Changing Models of Biomedical Research
Authors: Crowley William F. , Gusella James F.
Published: October 2009

The proper policy changes can place academic medical centers at the hub of a new style of translational research in the 21st century (or not).
Expansion of Allospecific Regulatory T Cells After Anergized, Mismatched Bone Marrow Transplantation
Authors: Davies Jeffrey K. , Nadler Lee M. , Guinan Eva C.
Published: October 2009

Transplantation of donor bone marrow cells treated to be tolerant to patient antigens results in expansion of regulatory T cells that suppress immune responses that mediate graft-versus-host disease.
β-Arrestin–Biased Parathyroid Hormone Ligands: A New Approach to the Development of Agents that Stimulate Bone Formation
Authors: Ferrari Serge L. , Bouxsein Mary L.
Published: October 2009

Because daily treatment with parathyroid hormone (PTH) increases bone mass and decreases fracture risk, physicians use this agent to treat osteoporosis. However, PTH stimulates both bone-forming and bone-resorbing cells, complicating its clinical use. New results show that, in mice, a so-called biased agonist (PTH-βarr) that selectively activates β–arrestin –dependent signaling leads to PTH-induced trabecular bone formation without a simultaneous increase in bone resorption. This targeted approach may pave the way for future pharmacological developments in the treatment of osteoporosis.
How Norepinephrine Neurons Contribute to Rett Syndrome
Authors: Kelner Katrina L.
Published: October 2009

Abnormally small, hyperexitable neurons in mice with Rett syndrome have reduced amounts of neurotransmitter, explaining some of the characteristics of the disorder.
Follicular Family
Authors: Khidr Lily
Published: October 2009

Treatment with imatinib, an effective anticancer agent, protects oocytes from damage induced by the chemotherapy drug cisplatin.
Specific Serodiagnosis of Canine Visceral Leishmaniasis Using
Leishmania
Species Ribosomal Protein Extracts
Authors: Coelho Eduardo A. F. , Ramírez Laura , Costa Mariana A. F. , Coelho Vinicio T. S. , Martins Vivian T. , Chávez-Fumagalli Miguel A. , Oliveira Dulcilene M. , Tavares Carlos A. P. , Bonay Pedro , Nieto Carlos Gómez , Abánades Daniel R. , Alonso Carlos , Soto Manuel
Published: October 2009

In the present work, we have analyzed the antigenicity of
Leishmania
species ribosomal proteins (LRPs). To accomplish this,
Leishmania infantum
ribosomes were biochemically purified from promastigote cytosolic extracts, and their reactivities were analyzed by using the sera from dogs naturally infected with
L. infantum
. Since antibodies reacting against different ribosomal proteins were observed in all the serum samples obtained from dogs with symptomatic visceral leishmaniasis tested, we have analyzed the potential usefulness of the LRP extracts in the development of an enzyme-linked immunosorbent assay (ELISA) for the serodiagnosis of canine visceral leishmaniasis (CVL) in an area of Brazil where visceral leishmaniasis is endemic due to infection by
Leishmania chagasi
. A comparative ELISA with crude soluble
Leishmania chagasi
antigen (SLA) and
L. infantum
LRPs was performed. LRP- and SLA-based ELISAs gave similar sensitivities for the diagnosis of symptomatic CVL, but the LRP extract provided a very high sensitivity for the detection of oligosymptomatic and asymptomatic dogs. In addition, an LRP-based ELISA showed a higher specificity when the sera from dogs harboring other infections were included in the analysis. The LRP antigen displayed no cross-reactivity with sera from dogs that had any of the other diseases tested, notably, Chagas' disease. Our findings suggest that LRPs are a potential tool for the diagnosis of CVL and will be particularly useful for the diagnosis of asymptomatic CVL.
Spurious Amplification of a
Plasmodium vivax
Small-Subunit RNA Gene by Use of Primers Currently Used To Detect
P. knowlesi
Authors: Imwong Mallika , Tanomsing Naowarat , Pukrittayakamee Sasithon , Day Nicholas P. J. , White Nicholas J. , Snounou Georges
Published: October 2009

The PCR primers commonly used to detect
Plasmodium knowlesi
infections in humans were found to cross-react stochastically with
P. vivax
genomic DNA. A nested primer set that targets one of the
P. knowlesi
small-subunit rRNA genes was validated for specificity and for sensitivity of detection of <10 parasite genomes.
Postoperative Mediastinitis Due to
Finegoldia magna
with Negative Blood Cultures
Authors: Kernéis Solen , Matta Matta , Hoï Annie Buu , Podglajen Isabelle , Gutmann Laurent , Novara Ana , Latremouille Christian , Mainardi Jean-Luc
Published: October 2009

We report a case of
Finegoldia magna
(formerly known as
Peptostreptococcus magnus
) mediastinitis following coronary artery bypass in a 50-year-old patient. Even if staphylococci remain the main causative organism of postoperative mediastinitis, the responsibility of anaerobic bacteria must be considered in cases of fever and sternal drainage with negative blood cultures.
Practical Disk Diffusion Test for Detecting Group B Streptococcus with Reduced Penicillin Susceptibility
Authors: Kimura Kouji , Wachino Jun-ichi , Kurokawa Hiroshi , Suzuki Satowa , Yamane Kunikazu , Shibata Naohiro , Arakawa Yoshichika
Published: October 2009

Although group B streptococcus (GBS) has been considered to be uniformly susceptible to β-lactams, the presence of GBS with reduced penicillin susceptibility (PRGBS) was recently confirmed genetically. We developed a feasible and reliable method for screening PRGBS in clinical microbiology laboratories using a combination of ceftibuten, oxacillin, and ceftizoxime disks.
Detection of Novel Sequences Related to African Swine Fever Virus in Human Serum and Sewage
Authors: Loh Joy , Zhao Guoyan , Presti Rachel M. , Holtz Lori R. , Finkbeiner Stacy R. , Droit Lindsay , Villasana Zoilmar , Todd Collin , Pipas James M. , Calgua Byron , Girones Rosina , Wang David , Virgin Herbert W.
Published: October 2009

The family
Asfarviridae
contains only a single virus species, African swine fever virus (ASFV). ASFV is a viral agent with significant economic impact due to its devastating effects on populations of domesticated pigs during outbreaks but has not been reported to infect humans. We report here the discovery of novel viral sequences in human serum and sewage which are clearly related to the asfarvirus family but highly divergent from ASFV. Detection of these sequences suggests that greater genetic diversity may exist among asfarviruses than previously thought and raises the possibility that human infection by asfarviruses may occur.
Heparan Sulfate Proteoglycans Are Required for Cellular Binding of the Hepatitis E Virus ORF2 Capsid Protein and for Viral Infection
Authors: Kalia Manjula , Chandra Vivek , Rahman Sheikh Abdul , Sehgal Deepak , Jameel Shahid
Published: October 2009

The hepatitis E virus (HEV), a nonenveloped RNA virus, is the causative agent of hepatitis E. The mode by which HEV attaches to and enters into target cells for productive infection remains unidentified. Open reading frame 2 (ORF2) of HEV encodes its major capsid protein, pORF2, which is likely to have the determinants for virus attachment and entry. Using an ∼56-kDa recombinant pORF2 that can self-assemble as virus-like particles, we demonstrated that cell surface heparan sulfate proteoglycans (HSPGs), specifically syndecans, play a crucial role in the binding of pORF2 to Huh-7 liver cells. Removal of cell surface heparan sulfate by enzymatic (heparinase) or chemical (sodium chlorate) treatment of cells or competition with heparin, heparan sulfate, and their oversulfated derivatives caused a marked reduction in pORF2 binding to the cells. Syndecan-1 is the most abundant proteoglycan present on these cells and, hence, plays a key role in pORF2 binding. Specificity is likely to be dictated by well-defined sulfation patterns on syndecans. We show that pORF2 binds syndecans predominantly via 6-O sulfation, indicating that binding is not entirely due to random electrostatic interactions. Using an in vitro infection system, we also showed a marked reduction in HEV infection of heparinase-treated cells. Our results indicate that, analogous to some enveloped viruses, a nonenveloped virus like HEV may have also evolved to use HSPGs as cellular attachment receptors.
Rift Valley Fever Virus L Protein Forms a Biologically Active Oligomer
Authors: Zamoto-Niikura Aya , Terasaki Kaori , Ikegami Tetsuro , Peters C. J. , Makino Shinji
Published: October 2009

Rift Valley fever virus
(RVFV) (genus
Phlebovirus
, family
Bunyaviridae
) causes mosquito-borne epidemic diseases in humans and livestock. The virus carries three RNA segments, L, M, and S, of negative or ambisense polarity. L protein, an RNA-dependent RNA polymerase, encoded in the L segment, and N protein, encoded in the S segment, exert viral RNA replication and transcription. Coexpression of N, hemagglutinin (HA)-tagged L, and viral minigenome resulted in minigenome replication and transcription, a finding that demonstrated HA-tagged L was biologically active. Likewise L tagged with green fluorescent protein (GFP) was biologically competent. Coimmunoprecipitation analysis using extracts from cells coexpressing HA-tagged L and GFP-tagged L showed the formation of an L oligomer. Bimolecular fluorescence complementation analysis and coimmunoprecipitation studies demonstrated the formation of an intermolecular L-L interaction through its N-terminal and C-terminal regions and also suggested an intramolecular association between the N-terminal and C-terminal regions of L protein. A biologically inactive L mutant, in which the conserved signature SDD motif was replaced by the amino acid residues GNN, exhibited a dominant negative phenotype when coexpressed with wild-type L in the minigenome assay system. Expression of this mutant L also inhibited viral gene expression in virus-infected cells. These data provided compelling evidence for the importance of oligomerization of RVFV L protein for its polymerase activity.
Identification of Hepatitis C Virus NS5A Inhibitors
Authors: Lemm Julie A. , O'Boyle Donald , Liu Mengping , Nower Peter T. , Colonno Richard , Deshpande Milind S. , Snyder Lawrence B. , Martin Scott W. , St. Laurent Denis R. , Serrano-Wu Michael H. , Romine Jeffrey L. , Meanwell Nicholas A. , Gao Min
Published: October 2009

Using a cell-based replicon screen, we identified a class of compounds with a thiazolidinone core structure as inhibitors of hepatitis C virus (HCV) replication. The concentration of one such compound, BMS-824, that resulted in a 50% inhibition of HCV replicon replication was ∼5 nM, with a therapeutic index of >10,000. The compound showed good specificity for HCV, as it was not active against several other RNA and DNA viruses. Replicon cells resistant to BMS-824 were isolated, and mutations were identified. A combination of amino acid substitutions of leucine to valine at residue 31 (L31V) and glutamine to leucine at residue 54 (Q54L) in NS5A conferred resistance to this chemotype, as did a single substitution of tyrosine to histidine at amino acid 93 (Y93H) in NS5A. To further explore the region(s) of NS5A involved in inhibitor sensitivity, genotype-specific NS5A inhibitors were used to evaluate a series of genotype 1a/1b hybrid replicons. Our results showed that, consistent with resistance mapping, the inhibitor sensitivity domain also mapped to the N terminus of NS5A, but it could be distinguished from the key resistance sites. In addition, we demonstrated that NS5A inhibitors, as well as an active-site inhibitor that specifically binds NS3 protease, could block the hyperphosphorylation of NS5A, which is believed to play an essential role in the viral life cycle. Clinical proof of concept has recently been achieved with derivatives of these NS5A inhibitors, indicating that small molecules targeting a nontraditional viral protein like NS5A, without any known enzymatic activity, can also have profound antiviral effects on HCV-infected subjects.
Effects of Major Capsid Proteins, Capsid Assembly, and DNA Cleavage/Packaging on the pU
L
17/pU
L
25 Complex of Herpes Simplex Virus 1
Authors: Scholtes Luella , Baines Joel D.
Published: October 2009

The U
L
17 and U
L
25 proteins (pU
L
17 and pU
L
25, respectively) of herpes simplex virus 1 are located at the external surface of capsids and are essential for DNA packaging and DNA retention in the capsid, respectively. The current studies were undertaken to determine whether DNA packaging or capsid assembly affected the pU
L
17/pU
L
25 interaction. We found that pU
L
17 and pU
L
25 coimmunoprecipitated from cells infected with wild-type virus, whereas the major capsid protein VP5 (encoded by the U
L
19 gene) did not coimmunoprecipitate with these proteins under stringent conditions. In addition, pU
L
17 (i) coimmunoprecipitated with pU
L
25 in the absence of other viral proteins, (ii) coimmunoprecipitated with pU
L
25 from lysates of infected cells in the presence or absence of VP5, (iii) did not coimmunoprecipitate efficiently with pU
L
25 in the absence of the triplex protein VP23 (encoded by the U
L
18 gene), (iv) required pU
L
25 for proper solubilization and localization within the viral replication compartment, (v) was essential for the sole nuclear localization of pU
L
25, and (vi) required capsid proteins VP5 and VP23 for nuclear localization and normal levels of immunoreactivity in an indirect immunofluorescence assay. Proper localization of pU
L
25 in infected cell nuclei required pU
L
17, pU
L
32, and the major capsid proteins VP5 and VP23, but not the DNA packaging protein pU
L
15. The data suggest that VP23 or triplexes augment the pU
L
17/pU
L
25 interaction and that VP23 and VP5 induce conformational changes in pU
L
17 and pU
L
25, exposing epitopes that are otherwise partially masked in infected cells. These conformational changes can occur in the absence of DNA packaging. The data indicate that the pU
L
17/pU
L
25 complex requires multiple viral proteins and functions for proper localization and biochemical behavior in the infected cell.
Conversion of VPg into VPgpUpU
OH
before and during Poliovirus Negative-Strand RNA Synthesis
Authors: Steil Benjamin P. , Barton David J.
Published: October 2009

There are two protein primers involved in picornavirus RNA replication, VPg, the viral protein of the genome, and VPgpUpU
OH
. A
cis
-acting replication element (CRE) within the open reading frame of poliovirus (PV) RNA allows the viral RNA-dependent RNA polymerase 3D
Pol
to catalyze the conversion of VPg into VPgpUpU
OH
. In this study, we used preinitiation RNA replication complexes (PIRCs) to determine when CRE-dependent VPg uridylylation occurs relative to the sequential synthesis of negative- and positive-strand RNA. Guanidine HCl (2 mM), a reversible inhibitor of PV 2C
ATPase
, prevented CRE-dependent VPgpUpU
OH
synthesis and the initiation of negative-strand RNA synthesis. VPgpUpU
OH
and nascent negative-strand RNA molecules were synthesized coincident in time following the removal of guanidine, consistent with PV RNA functioning simultaneously as a template for CRE-dependent VPgpUpU
OH
synthesis and negative-strand RNA synthesis. The amounts of [
32
P]UMP incorporated into VPgpUpU
OH
and negative-strand RNA products indicated that 100 to 400 VPgpUpU
OH
molecules were made coincident in time with each negative-strand RNA. 3′-dCTP inhibited the elongation of nascent negative-strand RNAs without affecting CRE-dependent VPg uridylylation. A 3′ nontranslated region mutation which inhibited negative-strand RNA synthesis did not inhibit CRE-dependent VPg uridylylation. Together, the data implicate 2C
ATPase
in the mechanisms whereby PV RNA functions as a template for reiterative CRE-dependent VPg uridylylation before and during negative-strand RNA synthesis.
Feeding Ecology of Capelin (Mallotus villosus) in the Estuary and Western Gulf of St. Lawrence and its Multispecies Implications
Authors: Vesin J-P. , Leggett W. C. , Able K. W.
Published: October 2009

The feeding ecology of juvenile (< 140 mm TL) and adult (> 140 mm TL) capelin (Mallotus villosus) in the St. Lawrence River Estuary and western Gulf of St. Lawrence was studied between October 1974 and October 1975. Both juveniles and adults fed almost exclusively on zooplankton. Three prey totally dominated the diet. Copepods were numerically most abundant but euphausiids were dominant in terms of biomass. Appendicularians ranked third in both number and biomass. This differed from the diet of capelin in the Canadian Atlantic only to the extent that amphipods replace appendicularians in the diet in the Atlantic and large copepods are more abundant in the diet there. A shift in diet occurred during growth. Premetamorphic capelin (< 75 mm TL) consumed small prey exclusively: invertebrate eggs, cyclopoid copepods, and diatoms predominated. The diets of juvenile (75–139 mm TL) and adult (> 140 mm TL) capelin overlapped considerably but a pronounced shift from small copepods to adult euphausiids occurred at ~ 140 mm TL. Early morning and evening feeding peaks occurred between May and August. A single midday feeding peak prevailed in October–November. Feeding of adult capelin was active in the spring prior to spawning but virtually ceased during spawning. Juvenile capelin fed actively throughout spring and summer. The daily ration of zooplankton by capelin was estimated to be 5% of wet body weight in summer May–September and ~ 2.5% in October–November. Year-to-year variations in average daily consumption in excess of 100 000 t have occurred between 1972 and 1978 and average daily consumption has declined by up to 310 000 t during the same interval. This significant year-to-year and long-term release of zooplankton from predation by capelin may be an important regulator of changes in year-class strength in other species of the area, notably arctic cod, Boreogadus saida and short-finned squid, Illex illecebrosus.Key words: capelin, Mallotus villosus; Gulf of St. Lawrence, ecology, food habits, daily ration, estuaries, zooplankton, multispecies interactions, arctic cod, Boreogadus saida; squid, Illex illecebrosus
Influence of Drilling Muds on the Primary Chemosensory Neurons in Walking Legs of the Lobster, Homarus americanus
Authors: Derby Charles D. , Atema Jelle
Published: October 2009

The effects of whole drilling muds on the normal activity of walking leg chemosensory neurons of the lobster, Homarus americanus, were examined using extracellular neurophysiological recording techniques. Exposure of legs for 3–5 min to 10 mg/L drilling mud suspended in seawater altered responses to food odors of 29% of the chemoreceptors examined (data pooled for the two drilling muds tested); similar exposure to 100 mg/L drilling mud resulted in interference with 44% of all receptors studied. The effects of both of these concentrations are statistically significant, although they are not different from each other. Interference was usually manifested as a marked reduction in the number of action potentials in a response. In one preparation, the exposure to drilling mud caused a change in the temporal pattern of the spikes without affecting the total number of spikes. Other chemosensory neurons were excited by 10 mg/L drilling mud itself. However, not all chemoreceptors are inhibited by these drilling muds since responses to feeding stimuli were recorded from the legs of lobsters that had been exposed to drilling mud for 4–8 d before the neurophysiological experiments.Antennular and leg chemoreceptors are important in eliciting normal feeding behavior in lobsters. Although behavioral assays have demonstrated that feeding behavior is altered following exposure to drilling muds and petroleum fractions, there is no conclusive proof for a causal relationship between chemoreceptor interference and behavioral deficits. The two techniques complement each other as pollution detection assays, perhaps reflecting a common interference mechanism.Key words: chemoreception, drilling mud, feeding behavior, lobster, pollution, neurophysiology
Equilibrium Model of Fate of Microcontaminants in Diverse Aquatic Food Chains
Authors: Thomann Robert V.
Published: October 2009

Bioconcentration and bioaccumulation factors of PCB, 239Pu, and 137Cs are compiled from the literature as a function of organism size. The distribution of field-observed bioaccumulation factors varies markedly between each substance but similarly to order of magnitude within each substance across diverse food chains. It can be inferred from the literature that PCB levels in top predators are due primarily to food chain transfer. A steady state compartment food chain model is derived for estimation of the relative effect of uptake directly from water versus food chain transfer. The model food chain transfer number f, given by αC/K + G for α = chemical absorption efficiency, C = specific consumption, K = excretion rate, and G = net organism growth rate indicates the degree of food chain accumulation. For f > 1, food chain transfer is significant; for f < 1, uptake from water is more significant. Application of the model suggests that (a) PCB body burden in top predators is due almost entirely to consumption of contaminated prey, (b) for 239Pu all of the body burden is due to uptake from the water only, and (c) observed 137Cs concentration factors are due principally to food chain transfer with a high dependence on the salinity-dependent phytoplankton adsorption.Key words: food chain model, bioconcentration, bioaccumulation, PCB, 239Pu, 137Cs, water uptake, food chain transfer
Evidence of Adaptive Polygenic Variation Between Two Populations of Atlantic Salmon (Salmo salar) Native to Tributaries of the S. W. Miramichi River, N.B.
Authors: Riddell Brian E. , Leggett William C. , Saunders Richard L.
Published: October 2009

Breeding experiments were conducted to test the hypothesis that spatial homeostasis in growth and proximate composition and geographic variation in body morphology and timing of migration in juvenile Atlantic salmon (Salmo salar) have an adaptive basis. The populations studied were Rocky Brook and Sabbies River, tributaries of the Southwest Miramichi River, New Brunswick. Growth rates and proximate composition were very similar in the two populations under hatchery conditions. Genetic contributions to homeostasis in these traits were largely additive. The phenotypic expression of migratory behavior and the genetic control of timing were not quantifiable. A genetic basis to interpopulation variation in body morphology was demonstrated. Progeny from Rocky Brook which exhibits higher flows had more fusiform bodies and longer fins than progeny from Sabbies River when reared under identical conditions. Heritable variation in morphology and a demonstrated directional selection for greater fin size in high velocity environments support the hypothesis that these traits are adaptive. Adaptive polygenic variation between local populations stresses the need to delineate stocks on a functional basis so that species can be managed without significant loss of fitness and/or depletion of genetic variation in natural populations.Key words: quantitative genetics, heritability, adaptation, morphology, growth, proximate composition, migration, Atlantic salmon, interdemic variation, directional selection
Northern Squawfish (Ptychocheilus oregonensis) Predation on Juvenile Salmonids in Sections of the Willamette River Basin, Oregon
Authors: Buchanan David V. , Hooton Robert M. , Moring John R.
Published: October 2009

Predation by northern squawfish (Ptychocheilus oregonensis) on salmonids was studied in spring months in several lower, free-flowing areas of the Willamette River drainage, Oregon. During 1976 and 1977, 1127 northern squawfish were collected by electrofishing and seining, and examined for food contents. Almost 59% of the squawfish stomachs contained food items, but only 2% contained salmonids. Principal foods were insects, crayfish, and sculpins (Cottidae), and the majority (over 90%) of squawfish had not consumed more than one principal food type. We suggest that previous reports of squawfish predation in flowing rivers were misleading because they were often based on artificial situations (below dams or in waters following hatchery releases) which could have inflated salmonid predation values. Further, the true predatory nature of squawfish is clouded because of their rapid digestion of food and the long lag time in examination of gut contents by previous researchers. Our sampling techniques avoided these shortcomings by sampling in free-flowing areas and by examining squawfish stomach contents immediately after capture.Key words: squawfish, Ptychocheilus oregonensis; predation, food habits, Oregon
Use of Beef Tallow as an Energy Source in Coho Salmon (Oncorhynchus kisutch) Rations
Authors: Yu T. C. , Sinnhuber R. O.
Published: October 2009

Four experimental diets containing different proportions of beef tallow and salmon oil were prepared. Each diet was fed to triplicate groups of juvenile coho salmon (Oncorhynchus kisutch) for 14 wk. The final fish weight was greatest with a diet containing 8% each of tallow and salmon oil. Fatty acid analysis indicated that the dietary salmon oil provided adequate quantities of the ω3 fatty acids required by the coho salmon. Fish body lipid saturation increased only slightly as the concentration of tallow in the diet increased. Beef tallow was found to be a good source of dietary energy when used in conjunction with a fish oil rich in ω3 fatty acids.Key words: beef tallow as source of dietary energy, coho salmon (Oncorhynchus kisutch), growth, feed efficiency, body lipid composition
Growth and Genetic Variation of Atlantic Salmon (Salmo salar) from Different Sections of the River Alta, North Norway
Authors: Heggberget Tor G. , Lund Roar A. , Ryman Nils , Ståhl Gunnar
Published: October 2009

Growth of young Atlantic salmon (Salmo salar) from three different sections of the River Alta was correlated with estimated growth differences among adult salmon caught in corresponding sections of the river. Young salmon grew most quickly each of the three years investigated in the upper section of the river; further downriver, presmolts had a significantly lower growth rate. Growth calculations based on scale samples from adults indicated corresponding river growth patterns from the three sections. Salmon caught in the upper section of the river had significantly lower smolt age (mean 3.92 yr) and better presmolt growth than salmon caught further downriver (mean smolt age in the middle and lower sections was 4.35 and 4.19 yr, respectively). Correlations between growth differences in young and adult salmon suggest that presmolts that have lived their first years in the upper section of the river apparently return there after having been at sea. Genetic analyses of presmolts indicate that local populations exist. Allele frequency differences at three electrophoretically detectable protein loci give independent support for the existence of genetically differentiated local populations within the River Alta.
Spatial Variability in Sedimentary Algal Microfossils and Its Bearing on Diatom-Inferred pH Reconstructions
Authors: Dixit Sushil S. , Evans R. Douglas
Published: October 2009

Spatial variability of algal microfossils was investigated in 20–21 surface (0–0.25 cm) sediment samples from Hannah and Clearwater lakes, Ontario, together with the variability in 20 downcore diatom-inferred pH profiles from Hannah Lake. Strong habitat-dependent spatial variability in the distribution of microfossils was observed in lakes of simple morphology. The abundance of planktonic taxa was high in deepwater sediments in both the lakes, while benthic taxa were common only in the sediments of shallow waters of Clearwater Lake. It is hypothesized that greater circulation and presence of sufficient light at all depths allowed benthic diatoms to flourish even in samples from the deep areas of Hannah Lake. The use of pH indicator diatom assemblages rather than individual taxa greatly reduced the variability in computing diatom-inferred pH. The variations were negligible within the samples collected from greater water depths. Results suggest that a single paleo-pH profile will provide an indication of the direction in change in pH, but that absolute pH results can be obtained only by utilizing several cores from many depth strata. The ability of index α and index B to accurately predict recent pH shifts of Hannah Lake was impaired because of its very acidic nature (pH < 4.5) in the past.
Effect of Stream Acidification on Periphyton Composition, Chlorophyll, and Productivity
Authors: Mulholland Patrick J. , Elwood J. W. , Palumbo A. V. , Stevenson R. J.
Published: October 2009

We determined periphyton community composition, cell number and biovolume, chlorophyll a density, and areal and chlorophyll-specific primary productivity along a pH (4.5–6.4) and total monomeric aluminum (0.018–0.242 mg∙L−1) gradient in high-elevation streams in the Great Smoky Mountains National Park (eastern Tennessee). The periphyton community was generally dominated by small chrysophytes and blue-green algae at sites with baseflow pH ≥ 5.5 and by diatoms and, to a lesser extent, green algae at sites with pH ≤ 5. Total cell biovolume, chlorophyll a density, and areal primary productivity were greatest at the most acidic sites. Chlorophyll-specific rates of primary production were not significantly different among sites, although the most acidic site was lowest. Experiments involving short-term manipulation of pH, inorganic carbon, PO4, and aluminum concentrations resulted in some statistically significant changes in chlorophyll-specific productivity, indicating that inorganic carbon concentrations at sites with pH < 6 and increased aluminum concentrations at sites with pH ≤ 5 may limit productivity at times. Studies of phosphatase activity and PO4 turnover indicated that the least acidic sites were the most phosphorus limited, perhaps the result of coprecipitation of aluminum and PO4 as pH increased downstream from acidified reaches. However, the low cell biovolume, Chlorophyll a density, and areal primary productivity at the second-order sites with pH ≥ 5.7, compared with the highly acidic second- and third-order sites (pH ≤ 5), appear to be the result of increased density of scraper/grazer macro-invertebrates at the higher pH sites. Low chlorophyll a density and areal primary productivity at the much larger fourth-order site (pH 6.4) may be the result of physical factors, such as increased scouring of the streambed, rather than chemical or biological factors.
Characterization of Cloned Mitochondrial DNA from the TeleostFundulus heteroclitusand its Usefulness as an Interspecies Hybridization Probe
Authors: González-Villaseñor Lucia Irene , Burkhoff Amanda M. , Corces Víctor , Powers Dennis A.
Published: October 2009

Analysis of mitochondrial DNA endonuclease restriction patterns is a powerful tool for studying related species and variation within species. The ethidium bromide staining technique has limited the number of digestions of mitochondrial DNA per individual. Because32P-end-labeling also imposes severe limitations, we have resorted to cloning the fish (Fundulus heteroclitus) mitochondrial genome in the lambda replacement vector EMBL-3. The clone was used as a radioactive probe via Southern blotting to detect mitochondrial DNA restriction fragments obtained by multiple restriction endonuclease digestions from small amounts of tissue. This technique offers much greater sensitivity than ethidium bromide staining. Moreover, it eliminates the expense and time to obtain highly purified mitochondrial DNA for the32P-end-labeling procedure. It is also useful when the mtDNA is prepared from frozen tissue which has been a problem with the32P-end-labeling technique. Because the cloned mitochondrial DNA has a high degree of cross-hybridization with the mitochondrial DNA of certain other fishes, it can be used to probe the mitochondrial DNA restriction patterns of a variety of fish species. However, its usefulness is restricted by the degree of relatedness to the species being cloned.
Limestone Slurry Reduces Physiological Stress and Increases Survival of Atlantic Salmon (Salmo salar) in an Acidic Norwegian River
Authors: Rosseland B. O. , Skogheim O. K. , Abrahamsen H. , Matzow D.
Published: October 2009

Smolts of Atlantic salmon (Salmo salar) were exposed for 70 h in the acidic River Vaaraana, southern Norway (Q = 1.3 m3/s, pH = 4.4–5.6, Ca = 0.6–1.5 mg/L, labile Al = 50–100 μg/L), to waters neutralized by addition of limestone slurry. Chemical and biological parameters were measured upstream of the liming site and 20, 100, 1000, 2000, and 3500 m downstream. Addition of limestone slurry effectively increased pH from 4.6 to 6.9, Ca from 0.6 to 2.6 mg/L, and reduced the labile Al concentration from 59 to 35 μg/L immediately downstream of the liming site (20 m, after 30 s). In the untreated upstream waters, salmon smolts lost plasma Cl rapidly, and all fish died within 36 h. In spite of the slight oversaturation of labile Al immediately downstream of the base addition, no mortality occurred in neutralized waters. Relatively high Ca concentrations may have mitigated potential toxic effects from Al oversaturation. Plasma Cl levels did not vary with distance downstream. Detoxification of running waters with highly toxic levels of pH and Al can successfully be performed by addition of limestone slurry.
Photosynthetic Characteristics of Lotic Periphyton
Authors: Jasper Stephen , Bothwell Max L.
Published: October 2009

Periphyton communities, grown in continuous-flow troughs, were suspended in filtered river water and placed in a photosynthesis–light incubator similar to those used for phytoplankton. A three-parameter equation was fitted to the incubator data. Seasonally the initial slope, α, ranged from 12.1 to 53.6 μg C∙(mg Chl a)−1∙h−1∙(μEinst.∙m−2∙s−1)−1; the maximum photosynthetic rate, PBmax, varied from 1.16 to 5.49 mgC∙(mg Chl a)−1∙h−1; and the inhibition parameter, Ib, ranged from 1500 to 6900 μEinst.∙m−2∙s−1. These values are similar to those reported for other periphyton and phytoplankton. PBmaxstrongly correlated with light history, whereas inhibition was inversely related to water temperature, α did not correlate with either irradiance or temperature but with changes in average cell size. Seasonal variations in the light level optimal for photosynthesis, Im, suggested a period in late winter and early spring for potentially serious inhibition of photosynthesis. These Chl a normalized photosynthetic parameters were unaffected by changes in concentration of the growth-limiting nutrient, phosphorus.
Winter Habitat Utilization by Stream Resident Brook Trout (Salvelinus fontinalis) and Brown Trout (Salmo trutta)
Authors: Cunjak Richard A. , Power Geoffrey
Published: October 2009

Habitat utilization by brook trout (Salvelinus fontinalis) and brown trout (Salmo trutta) is described from three winters of underwater observations in a southern Ontario river. Older trout (>age 1) generally occupied positions in deeper and faster water than age 0+ trout. In winter, at sites of sympatry, brown trout occupied greater focal point water depths than brook trout; both species had similar focal point water velocities. At all sites, and for both age groups and species, there was a strong preference for positions beneath cover. Relative to summer, trout positions in winter were characterized by slower water velocities and greater overhead cover, In winter, most trout were in aggregations, usually in pools beneath cover and close to point sources of groundwater discharge. Gregarious behaviour appeared to increase as water temperatures decreased; no such relationship was evident in the summer. Specific strategies for overwintering varied between sites and age groups but generally conformed to the theory of energetic cost minimization for position choice. These variable patterns appear to be adaptive.
Population Estimates of White Whale, Delphinapterus leucas, in James Bay, Eastern Hudson Bay, and Ungava Bay
Authors: Smith T. G. , Hammill M. O.
Published: October 2009

Coastal reconnaissance and systematic aerial surveys of white whales, Delphinapterus leucas, were flown in James Bay, eastern Hudson Bay, and Ungava Bay. In Ungava Bay the numbers of belugas are so low that we are unable to derive population estimates. In James Bay, we estimate 1213 whales with 95% confidence limits of 740–1970 individuals. In eastern Hudson Bay our systematic survey estimates 968 whales (650–1430), with an additional 474 whales counted in traditional areas of coastal concentration. The age structure of whales inshore and offshore appears similar. Our estimates are conservative, since they do not include a correction for animals which might have been underwater as we passed. Since belugas continue to be hunted in Ungava Bay and eastern Hudson Bay, recommendations are made for a conservative management strategy which must soon be implemented.
Input–Output Nutrient Budgets for Small Diked Marshes
Authors: Kadlec John A.
Published: October 2009

Input–output nutrient budgets were constructed for 8 and 10 diked contiguous 4- to 6-ha marshes in 1981 and 1982, respectively. Because the marshes studied were created by diking within a larger marsh, the water budgets were dominated by water pumped in to replace roughly equal evapotranspiration and seepage losses. Chloride budgets could not be used to confirm water budgets, apparently because of a transfer to the sediments by a freezing-out process in winter and a subsequent diffusion back into the surface water during the ice-free season. With replicated ponds and accurate water budgets, good agreement was found among replicates for annual budgets for the major ions and total N. However, the budgets for total P were highly variable, reflecting the biological activity of P. Atmospheric inputs of N and P were large components of budgets for these nutrients. Year to year increases in surface water concentrations of major ions, expected on the basis of evaporative water loss, did not occur, apparently because of freezing-out of these ions in winter.
Investigation sur la toxicodynamique du cyanure et sur sa biotransformation chez la truite arc-en-ciel (Salmo gairdneri)
Authors: Raymond Pierre , Leduc Gérard , Kornblatt Jack A.
Published: October 2009

The exposure of rainbow trout (Salmo gairdneri) to 0.01, 0.02 and 0.03 mg HCN∙L−1 for 20 d demonstrated the biotransformation of HCN into thiocyanate which accumulated in the blood plasma which increased the duration of exposure to cyanide. Despite its transformation into thiocyanate, there is still a sufficient quantity of cyanide to inhibit cytochrome oxidase by 60–80% within the first 24 h of exposure. This level of inhibition remained stable during the 20 d of the tests and was the same at the three concentrations tested. This observation permits the prediction of effective concentration of free HCN inside the fish. The measurements of liver glycogen levels illustrate the Pasteur effect in the rainbow trout subjected to cyanide. During cyanide exposure, liver glycogen was rapidly used, particularly at 0.03 mg HCN∙L−1 whereas at 0.01 and 0.02 mg HCN∙L−1 the glycogen levels gradually came back to normal after 7–10 d of exposure.
Variation in Major Ion Concentration ofCambarus robustusandOrconectes rusticusFollowing Exposure to Low pH
Authors: Hollett Lois , Berrill Michael , Rowe Locke
Published: October 2009

Cambarus robustus is more tolerant of low environmental pH than Orconectes rusticus and this tolerance reflects a difference in ion regulation physiology. Chronic exposure (96 h) of the acid-tolerant C. robustus to pH 3.8 soft water did not significantly change haemolymph [Na+] or [Ca2+] of the adults or total body [Na+] of the juveniles relative to the control (pH 6.5). In contrast, the intolerant O. rusticus showed a significant decrease in [Na+] and increase in [Ca2+] in adult haemolymph (Wood and Rogano. 1986. Can. J. Fish. Aquat. Sci. 43: 1017–1026) and an increase in total body [Na+] of stage III juveniles following acute exposure to pH 3.8 compared with the pH 6.5 control.
A proposal for typical eukaryotic meiosis in microsporidians
Authors: Flegel T. W. , Pasharawipas Tirasak
Published: October 2009

A review of key publications concerning the biology and life cycles of microsporidians has led us to challenge recent proposals that they exhibit a unique process of meiosis when compared with other eukaryotes. The basic data used to support this challenge are the same as those used by researchers suggesting atypical meiosis, but the data are analyzed from a different viewpoint. Arguments are put forward to support a testable hypothesis that meiosis in microsporidians is identical to that which occurs in other eukaryotes. It is proposed that confusion resulted because two separate cytological developmental sequences for diplokaryotic meronts in mosquito fat body cells were previously interpreted as a single sequence. By rearrangement of the original data into two developmental sequences, one abortive and the other for typical meiosis, a better fit was obtained between cytological stages and microphotometric measurements of nuclear DNA content. This improved data fit and the existence of similar nuclear developmental sequences in the fungi are used to support our hypothesis.Key words: microsporidia, meiosis, eukaryotes.