bluuebunny/crossref_metadata_2025 huggingface dataset:
Highly Sensitive Amperometric Immunosensor for Detection of
Plasmodium falciparum
Histidine-Rich Protein 2 in Serum of Humans with Malaria: Comparison with a Commercial Kit
Authors: Sharma Mukesh K. , Rao Vepa K. , Agarwal Gauri S. , Rai Ganga P. , Gopalan N. , Prakash Shri , Sharma S. K. , Vijayaraghavan R.
Published: September 2008

A disposable amperometric immunosensor was developed for the detection of
Plasmodium falciparum
histidine-rich protein 2 (PfHRP-2) in the sera of humans with
P. falciparum
malaria. For this purpose, disposable screen-printed electrodes (SPEs) were modified with multiwall carbon nanotubes (MWCNTs) and Au nanoparticles. The electrodes were characterized by cyclic voltammetry, scanning electron microscopy, and Raman spectroscopy. In order to study the immunosensing performances of modified electrodes, a rabbit anti-PfHRP-2 antibody (as the capturing antibody) was first immobilized on an electrode. Further, the electrode was exposed to a mouse anti-PfHRP-2 antibody from a serum sample (as the revealing antibody), followed by a rabbit anti-mouse immunoglobulin G-alkaline phosphatase conjugate. The immunosensing experiments were performed on bare SPEs, MWCNT-modified SPEs, and Au nanoparticle- and MWCNT-modified SPEs (Nano-Au/MWCNT/SPEs) for the amperometric detection of PfHRP-2 in a solution of 0.1 M diethanolamine buffer, pH 9.8, by applying a potential of 450 mV at the working electrode. Nano-Au/MWCNT/SPEs yielded the highest-level immunosensing performance among the electrodes, with a detection limit of 8 ng/ml. The analytical results of immunosensing experiments with human serum samples were compared with the results of a commercial Paracheck Pf test, as well as the results of microscopy. The specificities, sensitivities, and positive and negative predictive values of the Paracheck Pf and amperometric immunosensors were calculated by taking the microscopy results as the “gold standard.” The Paracheck Pf kit exhibited a sensitivity of 79% (detecting 34 of 43 positive samples; 95% confidence interval [CI], 75 to 86%) and a specificity of 81% (correctly identifying 57 of 70 negative samples; 95% CI, 76 to 92%), whereas the developed amperometric immunosensor showed a sensitivity of 96% (detecting 41 of 43 positive samples; 95% CI, 93 to 98%) and a specificity of 94% (correctly identifying 66 of 70 negative samples; 95% CI, 92 to 99%). The developed method is more sensitive and specific than the Paracheck Pf kit.
Real-Time Reverse-Transcription Loop-Mediated Isothermal Amplification for Rapid Detection of Rift Valley Fever Virus
Authors: Peyrefitte Christophe N. , Boubis Laetitia , Coudrier Daniel , Bouloy Michèle , Grandadam Marc , Tolou Hugues J. , Plumet Sébastien
Published: September 2008

The development and validation of a one-step, single-tube, real-time accelerated reverse-transcription loop-mediated isothermal amplification (RT-LAMP) for the detection of the L RNA segment of Rift Valley fever virus (RVFV) are described. The assay was performed at a constant temperature (63°C), with a real-time follow-up using a LightCycler and a double-stranded-DNA-intercalating fluorochrome. The assay is highly sensitive and comparable to real-time RT-PCR, with a detection limit of ∼10 RNA copies per assay. However, the RT-LAMP assay is much faster than traditional RT-PCR and generates results in <30 min for most diluted samples. The specificity of the primers was established using other, related arboviruses as well as virus-containing and virus-free sera. The RT-LAMP assay reported here is thus a valuable tool for the rapid detection of RVFV in field diagnostic laboratories.
Identities of
Microbacterium
spp. Encountered in Human Clinical Specimens
Authors: Gneiding Kathrina , Frodl Reinhard , Funke Guido
Published: September 2008

In the present study, 50 strains of yellow-pigmented gram-positive rods that had been isolated from human clinical specimens and collected over a 5-year period were further characterized by phenotypic and molecular genetic methods. All 50 strains belonged to the genus
Microbacterium
, and together they represented 18 different species.
Microbacterium oxydans
(
n
= 11),
M. paraoxydans
(
n
= 9), and
M. foliorum
(
n
= 7) represented more than half of the strains included in the present study. The isolation of strains belonging to
M. hydrocarbonoxydans
(
n
= 2),
M. esteraromaticum
(
n
= 1),
M. oleivorans
(
n
= 1),
M. phyllosphaerae
(
n
= 1), and
M. thalassium
(
n
= 1) from humans is reported for the first time.
Microbacterium
sp. strain VKM Ac-1389 (
n
= 1) and the previously uncultured
Microbacterium
sp. clone YJQ-29 (
n
= 1) probably represent new species. Comprehensive antimicrobial susceptibility data are given for the 50
Microbacterium
isolates. This study is, so far, the largest on
Microbacterium
spp. encountered in human clinical specimens and outlines the heterogeneity of clinical
Microbacterium
strains.
Evaluation of New Colorimetric Vitek 2 Yeast Identification Card by Use of Different Source Media
Authors: Valenza Giuseppe , Strasen Jörn , Schäfer Frauke , Frosch Matthias , Kurzai Oliver , Abele-Horn Marianne
Published: September 2008

The new colorimetric Vitek 2 YST card was evaluated for identification of yeasts (136 strains) with respect to the influence of different source media. The Vitek 2 YST card achieved satisfactory results for all yeast species tested, with the exception of
Candida guilliermondii
,
Candida norvegensis
,
Candida parapsilosis
,
Candida rugosa
, and
Candida tropicalis.
After simple additional tests, 93.7% of all the strains tested were correctly identified. A significant influence of the isolation medium on the identification rate could not be observed.
Cost-Effectiveness of Different Strategies for Amplified
Mycobacterium tuberculosis
Direct Testing for Cases of Pulmonary Tuberculosis
Authors: Guerra Renata L. , Hooper Nancy M. , Baker James F. , Alborz Roya , Armstrong Derek T. , Kiehlbauch Julia A. , Conde Marcus B. , Dorman Susan E.
Published: September 2008

We conducted a decision analysis to assess and compare four algorithms for amplified
Mycobacterium tuberculosis
direct (MTD) testing of respiratory specimens in terms of cost-effectiveness. The most cost-effective strategy was one in which smear-positive specimens but not smear-negative specimens were diluted prior to MTD testing.
Cyclin-Dependent Kinase 1/Cyclin B1 Phosphorylates Varicella-Zoster Virus IE62 and Is Incorporated into Virions
Authors: Leisenfelder Stacey A. , Kinchington Paul R. , Moffat Jennifer F.
Published: September 2008

Varicella-zoster virus (VZV), an alphaherpesvirus restricted to humans, infects differentiated cells in vivo, including T lymphocytes, keratinocytes, and neurons, and spreads rapidly in confluent cultured dermal fibroblasts (HFFs). In VZV-infected HFFs, atypical expression of cyclins D3 and B1 occurs along with the induction of cyclin-dependent kinase (CDK) activity. A specific CDK1 inhibitor blocked VZV spread, indicating an important function for this cellular kinase in VZV replication. CDK activity assays of infected cells revealed a large viral phosphoprotein that was identified as being the major immediate-early transactivator, IE62. Since IE62 colocalized with CDK1/cyclin B1 by confocal microscopy, we investigated whether this cellular kinase complex interacts with IE62. Using recombinant fragments of IE62 spanning the entire amino acid sequence, we found that purified CDK1/cyclin B1 phosphorylated IE62 at residues T10, S245, and T680 in vitro. Immunoprecipitation of cyclin B1 from VZV-infected HFFs indicated that IE62 was included in the complex within infected cells. The full-length IE62 protein, obtained by immunoprecipitation from infected cells, was also phosphorylated by purified CDK1/cyclin B1. Based on IE62/CDK1/cyclin B1 colocalization near viral assembly regions, we hypothesized that these cellular proteins could be incorporated into VZV virions with IE62. Purified virions were analyzed by immunoblotting for the presence of CDK1 and cyclin B1, and active CDK1 and cyclin B1 were present in the VZV tegument with IE62 and were sensitive to detergent treatment. Thus, IE62 is a substrate for CDK1/cyclin B1, and virions could deliver the active cellular kinase to nondividing cells that normally do not express it.
Identification of Postentry Restrictions to Mason-Pfizer Monkey Virus Infection in New World Monkey Cells
Authors: Diehl William E. , Stansell Elizabeth , Kaiser Shari M. , Emerman Michael , Hunter Eric
Published: September 2008

TRIM5α has been shown to be a major postentry determinant of the host range for gammaretroviruses and lentiviruses and, more recently, spumaviruses. However, the restrictive potential of TRIM5α against other retroviruses has been largely unexplored. We sought to determine whether or not Mason-Pfizer monkey virus (M-PMV), a prototype betaretrovirus isolated from rhesus macaques, was sensitive to restriction by TRIM5α. Cell lines from both Old World and New World primate species were screened for their susceptibility to infection by vesicular stomatitis virus G protein pseudotyped M-PMV. All of the cell lines tested that were established from Old World primates were found to be susceptible to M-PMV infection. However, fibroblasts established from three New World monkey species specifically resisted infection by this virus. Exogenously expressing TRIM5α from either tamarin or squirrel monkeys in permissive cell lines resulted in a block to M-PMV infection. Restriction in the resistant cell line of spider monkey origin was determined to occur at a postentry stage. However, spider monkey TRIM5α expression in permissive cells failed to restrict M-PMV infection, and interference with endogenous TRIM5α in the spider monkey fibroblasts failed to relieve the block to infectivity. Our results demonstrate that TRIM5α specificity extends to betaretroviruses and suggest that New World monkeys have evolved additional mechanisms to restrict the infection of at least one primate betaretrovirus.
Human Immunodeficiency Virus Type 1 Nef Induces Programmed Death 1 Expression through a p38 Mitogen-Activated Protein Kinase-Dependent Mechanism
Authors: Muthumani Karuppiah , Choo Andrew Y. , Shedlock Devon J. , Laddy Dominick J. , Sundaram Senthil G. , Hirao Lauren , Wu Ling , Thieu Khanh P. , Chung Christopher W. , Lankaraman Karthikbabu M. , Tebas Pablo , Silvestri Guido , Weiner David B.
Published: September 2008

Chronic viral infection is characterized by the functional impairment of virus-specific T-cell responses. Recent evidence has suggested that the inhibitory receptor programmed death 1 (PD-1) is specifically upregulated on antigen-specific T cells during various chronic viral infections. Indeed, it has been reported that human immunodeficiency virus (HIV)-specific T cells express elevated levels of PD-1 and that this expression correlates with the viral load and inversely with CD4+T-cell counts. More importantly, antibody blockade of the PD-1/PD-L1 pathway was sufficient to both increase and stimulate virus-specific T-cell proliferation and cytokine production. However, the mechanisms that mediate HIV-induced PD-1 upregulation are not known. Here, we provide evidence that the HIV type 1 (HIV-1) accessory protein Nef can transcriptionally induce the expression of PD-1 during infection in vitro. Nef-induced PD-1 upregulation requires its proline-rich motif and the activation of the downstream kinase p38. Further, inhibition of Nef activity by p38 MAPK inhibitor effectively blocked PD-1 upregulation, suggesting that p38 MAPK activation is an important initiating event in Nef-mediated PD-1 expression in HIV-1-infected cells. These data demonstrate an important signaling event of Nef in HIV-1 pathogenesis.
Measles Viruses Possessing the Polymerase Protein Genes of the Edmonston Vaccine Strain Exhibit Attenuated Gene Expression and Growth in Cultured Cells and SLAM Knock-In Mice
Authors: Takeda Makoto , Ohno Shinji , Tahara Maino , Takeuchi Hiroki , Shirogane Yuta , Ohmura Hirofumi , Nakamura Takafumi , Yanagi Yusuke
Published: September 2008

Live attenuated vaccines against measles have been developed through adaptation of clinical isolates of measles virus (MV) in various cultured cells. Analyses using recombinant MVs with chimeric genomes between wild-type and Edmonston vaccine strains indicated that viruses possessing the polymerase protein genes of the Edmonston strain exhibited attenuated viral gene expression and growth in cultured cells as well as in mice expressing an MV receptor, signaling lymphocyte activation molecule, regardless of whether the virus genome had the wild-type or vaccine-type promoter sequence. These data demonstrate that the polymerase protein genes of the Edmonston strain contribute to its attenuated phenotype.
The TRIM5α B-Box 2 Domain Promotes Cooperative Binding to the Retroviral Capsid by Mediating Higher-Order Self-Association
Authors: Li Xing , Sodroski Joseph
Published: September 2008

The retroviral restriction factor, TRIM5α, blocks infection of a spectrum of retroviruses soon after virus entry into the cell. TRIM5α consists of RING, B-box 2, coiled-coil, and B30.2(SPRY) domains. The B-box 2 domain is essential for retrovirus restriction by TRIM5α, but its specific function is unknown. We show here that the B-box 2 domain mediates higher-order self-association of TRIM5α
rh
oligomers. This self-association increases the efficiency of TRIM5α binding to the retroviral capsid, thus potentiating restriction of retroviral infection. The contribution of the B-box 2 domain to cooperative TRIM5α association with the retroviral capsid explains the conditional nature of the restriction phenotype exhibited by some B-box 2 TRIM5α mutants; the potentiation of capsid binding that results from B-box 2-mediated self-association is essential for restriction when B30.2(SPRY) domain-mediated interactions with the retroviral capsid are weak. Thus, B-box 2-dependent higher-order self-association and B30.2(SPRY)-dependent capsid binding represent complementary mechanisms whereby sufficiently dense arrays of capsid-bound TRIM5α proteins can be achieved.
Biochemical Characterization of a Recombinant TRIM5α Protein That Restricts Human Immunodeficiency Virus Type 1 Replication
Authors: Langelier Charles R. , Sandrin Virginie , Eckert Debra M. , Christensen Devin E. , Chandrasekaran Viswanathan , Alam Steven L. , Aiken Christopher , Olsen John C. , Kar Alak Kanti , Sodroski Joseph G. , Sundquist Wesley I.
Published: September 2008

The rhesus monkey intrinsic immunity factor TRIM5α
rh
recognizes incoming capsids from a variety of retroviruses, including human immunodeficiency virus type 1 (HIV-1) and equine infectious anemia virus (EIAV), and inhibits the accumulation of viral reverse transcripts. However, direct interactions between restricting TRIM5α proteins and retroviral capsids have not previously been demonstrated using pure recombinant proteins. To facilitate structural and mechanistic studies of retroviral restriction, we have developed methods for expressing and purifying an active chimeric TRIM5α
rh
protein containing the RING domain from the related human TRIM21 protein. This recombinant TRIM5-21R protein was expressed in SF-21 insect cells and purified through three chromatographic steps. Two distinct TRIM5-21R species were purified and shown to correspond to monomers and dimers, as analyzed by analytical ultracentrifugation. Chemically cross-linked recombinant TRIM5-21R dimers and mammalian-expressed TRIM5-21R and TRIM5α proteins exhibited similar sodium dodecyl sulfate-polyacrylamide gel electrophoresis mobilities, indicating that mammalian TRIM5α proteins are predominantly dimeric. Purified TRIM5-21R had ubiquitin ligase activity and could autoubquitylate with different E2 ubiquitin conjugating enzymes in vitro. TRIM5-21R bound directly to synthetic capsids composed of recombinant HIV-1 CA-NC proteins and to authentic EIAV core particles. HIV-1 CA-NC assemblies bound dimeric TRIM5-21R better than either monomeric TRIM5-21R or TRIM5-21R constructs that lacked the SPRY domain or its V1 loop. Thus, our studies indicate that TRIM5α proteins are dimeric ubiquitin E3 ligases that recognize retroviral capsids through direct interactions mediated by the SPRY domain and demonstrate that these activities can be recapitulated in vitro using pure recombinant proteins.
Generation of a Conditionally Replicating Adenovirus Based on Targeted Destruction of E1A mRNA by a Cell Type-Specific MicroRNA
Authors: Ylösmäki Erkko , Hakkarainen Tanja , Hemminki Akseli , Visakorpi Tapio , Andino Raul , Saksela Kalle
Published: September 2008

MicroRNAs have emerged as important players in tissue-specific mammalian gene regulation and have also been exploited in experimental targeting of gene expression. We have constructed a recombinant adenovirus that contains sequences complementary to the liver-specific microRNA 122 (miR122) in the 3′ untranslated region of the E1A gene. In Huh7 cells, which resemble normal hepatocytes in expressing high levels of miR122, this feature resulted in strongly reduced levels of E1A mRNA and protein. This property allowed us to generate a novel recombinant adenovirus that was severely attenuated in cells of hepatic origin but replicated normally in other cells. This strategy may be useful in circumventing liver toxicity associated with the systemic delivery of oncolytic adenoviruses. These data provide the first example of exploiting differential microRNA expression patterns to alter the natural tropism of a DNA virus. In addition, these results suggest that other microRNAs expressed in a tissue- or transformation-specific manner may also be used for the targeting of adenoviral replication and that the same principle may be applied to other viruses that have shown promise as oncolytic or gene delivery platforms.
Residues in the Stalk Domain of the Hendra Virus G Glycoprotein Modulate Conformational Changes Associated with Receptor Binding
Authors: Bishop Kimberly A. , Hickey Andrew C. , Khetawat Dimple , Patch Jared R. , Bossart Katharine N. , Zhu Zhongyu , Wang Lin-Fa , Dimitrov Dimiter S. , Broder Christopher C.
Published: September 2008

Hendra virus
(HeV) is a member of the broadly tropic and highly pathogenic paramyxovirus genus
Henipavirus
. HeV is enveloped and infects cells by using membrane-anchored attachment (G) and fusion (F) glycoproteins. G possesses an N-terminal cytoplasmic tail, an external membrane-proximal stalk domain, and a C-terminal globular head that binds the recently identified receptors ephrinB2 and ephrinB3. Receptor binding is presumed to induce conformational changes in G that subsequently trigger F-mediated fusion. The stalk domains of other attachment glycoproteins appear important for oligomerization and F interaction and specificity. However, this region of G has not been functionally characterized. Here we performed a mutagenesis analysis of the HeV G stalk, targeting a series of isoleucine residues within a hydrophobic α-helical domain that is well conserved across several attachment glycoproteins. Nine of 12 individual HeV G alanine substitution mutants possessed a complete defect in fusion-promotion activity yet were cell surface expressed and recognized by a panel of conformation-dependent monoclonal antibodies (MAbs) and maintained their oligomeric structure. Interestingly, these G mutations also resulted in the appearance of an additional electrophoretic species corresponding to a slightly altered glycosylated form. Analysis revealed that these G mutants appeared to adopt a receptor-bound conformation in the absence of receptor, as measured with a panel of MAbs that preferentially recognize G in a receptor-bound state. Further, this phenotype also correlated with an inability to associate with F and in triggering fusion even after receptor engagement. Together, these data suggest the stalk domain of G plays an important role in the conformational stability and receptor binding-triggered changes leading to productive fusion, such as the dissociation of G and F.
Volcanic sulfur dioxide and acute respiratory symptoms on Miyakejima island
Authors: Ishigami A , Kikuchi Y , Iwasawa S , Nishiwaki Y , Takebayashi T , Tanaka S , Omae K
Published: September 2008

Objectives:

Following a volcanic eruption in 2000, high concentrations of ambient sulfur dioxide (SO2) are still observed on Miyakejima, Japan despite the reversal 2 years ago of the ban on residents living on the island. This study examines the association between current levels of volcanic SO2and the incidence of acute subjective symptoms in volunteers on Miyakejima.

Methods:

The authors conducted a follow-up study on 611 healthy volunteers, on a person-hour basis (28 413 person-hours), who visited the island to provide support to residents from February to July 2005. Adverse health symptoms were measured by self-administered diary and exposure was approximated using monitoring data across 14 sites. Associations between incidence rates and increasing SO2levels (reference (the lowest), very low, low, middle and high) were examined using Poisson regression.

Results:

Hourly incidence of cough, scratchy throat, sore throat and breathlessness showed clear exposure–response relationships with SO2concentrations. There were statistically significant risks of those symptoms at relatively low SO2levels. Thus, rate ratios in the 0.6-2.0 ppm exposure band (vs <0.01 ppm) were: for cough, 3.4 (95% CI 1.8 to 6.6) in men and 9.8 (3.9 to 24.9) in women; for sore throat, 3.2 (1.7 to 6.2) in men and 5.8 (2.0 to 16.5) in women; and for breathlessness, 10.5 (4.2 to 26.6) in men and 18.5 (4.6 to 74.3) in women. Little evidence of SO2effects on sputum and nasal discharge/congestion was observed in this study. Eye and skin irritations showed inconsistent results between hourly maximal and hourly mean SO2concentrations.

Conclusion:

The authors observed strong evidence of an exposure–response relationship between volcanic SO2and subjective acute respiratory symptoms among a healthy population on Miyakejima. The results are consistent with reports that females and non-smokers are more sensitive to irritant gas than males and smokers, respectively.
A panel study in congestive heart failure to estimate the short-term effects from personal factors and environmental conditions on oxygen saturation and pulse rate
Authors: Goldberg M S , Giannetti N , Burnett R T , Mayo N E , Valois M-F , Brophy J M
Published: September 2008

Objectives:

Recent studies suggest that persons with congestive heart failure (CHF) may be at higher risk for short-term effects of air pollution. This daily diary panel study in Montreal, Quebec, was carried out to determine whether oxygen saturation and pulse rate were associated with selected personal factors, weather conditions and air pollution.

Methods:

Thirty-one subjects with CHF participated in this study in 2002 and 2003. Over a 2-month period, the investigators measured their oxygen saturation, pulse rate, weight and temperature each morning and recorded these and other data in a daily diary. Air pollution and weather conditions were obtained from fixed-site monitoring stations. The study made use of mixed regression models, adjusting for within-subject serial correlation and temporal trends, to determine the association between oxygen saturation and pulse rate and personal and environmental variables. Depending on the model, we accounted for the effects of a variety of personal variables (eg, body temperature, salt consumption) as well as nitrogen dioxide (NO2), ozone, maximum temperature and change in barometric pressure at 8:00 from the previous day.

Results:

In multivariable analyses, the study found that oxygen saturation was reduced when subjects reported that they were ill, consumed salt, or drank liquids on the previous day and had higher body temperatures on the concurrent day (only the latter was statistically significant). Relative humidity and decreased atmospheric pressure from the previous day were associated with oxygen saturation. In univariate analyses, there was negative associations with concentrations of fine particulates, ozone, and sulphur dioxide (SO2), but only SO2was significant after adjustment for the effects of weather. For pulse rate, no associations were found for the personal variables and in univariate analyses the study found positive associations with NO2, fine particulates (aerodynamic diameter of 2.5 μm or under, PM2.5), SO2, and maximum temperature, although only the latter two were significant after adjustment for environmental effects.

Conclusions:

The findings from the present investigation suggest that personal and environmental conditions affect intermediate physiological parameters that may affect the health of CHF patients.
Quasi-likelihood Estimation of Marked Fish Recapture
Authors: Bayley Peter B.
Published: September 2008

In models of the fraction of fish recaptured in field experiments on gear efficiency the binomial error distribution is usually assumed. However, variance in excess of that defined by the error distribution (overdispersion) is typical in fish capture because of heterogeneity among and within groups of individuals and incomplete model specification. Quasi-likelihood offers a parsimonious solution to the typical problem of incomplete definition of an error distribution with discrete responses. An example is given from the recapture of marked fish following rotenone treatment in lake enclosures, in which a generalized linear-logistic model includes an extra-binomial variance as a function of the mean. Estimated standard errors of fitted parameters were two to three times lower in a linear-logistic maximum likelihood model than in the quasi-likelihood model because extra-binomial variation (overdispersion) was ignored in the former model. In a cross-validation trial, 95% confidence intervals included 85% of independent observations with the quasi-likelihood model compared with 69% with the maximum likelihood model.
Effects of Exercise Conditioning on Stress Responses and Recovery in Cultured and Wild Young-of-the-Year Striped Bass, Morone saxatilis
Authors: Young Paciencia S. , Cech Jr. Joseph J.
Published: September 2008

Exercise conditioning at 1.2–2.4 body lengths∙s−1 for 60 d significantly improved physiological responses to and decreased recovery time from capture, net confinement, and crowding (collectively, "handling") stress in cultured and wild young-of-the-year striped bass, Morone saxatilis. Plasma cortisol increased dramatically 0.5 h after acute handling in all treatments. However, cortisol returned to prestress levels 4 h after handling in exercise-conditioned cultured and wild fish but not in the respective unexercised fish. Handling stress in all groups of fish also resulted in hyperlacticemia. Faster clearance of plasma lactate following handling stress was shown in exercise-conditioned cultured and wild striped bass compared with unexercised fish. Handling stress resulted in a rapid hemoconcentration as indicated by increases in osmolality and hematocrit levels. Osmotic imbalance was less severe in exercise-conditioned cultured and wild fish than in unexercised fish. These improved stress responses and enhanced recovery in young-of-the-year striped bass should result in increased survival of both cultured and wild fish after transport and stocking into the natural environment.
Changes in Habitat Use and Feeding Chronology of Juvenile Rainbow Trout (Oncorhynchus mykiss) in Fall and the Onset of Winter in Silver Creek, Idaho
Authors: Riehle Michael D. , Griffith J. S.
Published: September 2008

We assessed changes in density, distribution, and microhabitat of age-0 rainbow trout (Oncorhynchus mykiss) in Silver Creek, a partially spring-fed stream, by periodic snorkeling in August 1987 through January 1988. We examined trout stomach contents and invertebrate drift samples in diel collections in August, September, October, and January to test if the period of feeding shifted from daytime to nighttime, concurrent with a transition to day concealment. In late September, fish aggregated briefly during the day and then began to conceal themselves in macrophyte beds, undercut banks, and submerged sedges and grasses along streambanks as temperature dropped below 8 °C in early October. Fish emerged from concealment at night, and numbers of trout visible were greatest 30–60 min after sunset and about 30 min before sunrise. Periods of peak feeding changed from afternoon and evening in August and September, when fish were day active, to mainly at night in October after the initiation of day concealment. Trout did not feed upon abundant chironomids in the daytime drift in October. In January, fish fed at 1–4 °C on mayflies, and stomachs were fullest in the early morning. Observations suggest that Silver Creek trout experienced a metabolic deficit that began in September.
An in situ Evaluation of the Day-to-Day Variation in the Quantity of Food Consumed by Fish
Authors: Trudel Marc , Boisclair Daniel
Published: September 2008

We tested the hypothesis that the mean quantity food consumed by fish in situ does not vary significantly over successive days. The daily ration of minnows (Phoxinus eos × P. neogaeus) was estimated over 5–12 consecutive days (June 1–5, July 6–17, and August 3–9, 1992). Mean daily ration ranged from 0.60 to 1.32 g dry∙100 g wet−1∙d−1 and varied significantly over consecutive days in June and July, but not in August. Average day-to-day variation in food consumption rates ranged from 7.0 to 16.3%. Mean daily ration was not influenced by either water temperature or percent cloudiness. Simulated long-term consumption rates of minnows did not vary by more than 19.3% among sampling intervals ranging from 1 to 30 d. We conclude that long-term consumption rates can be accurately determined using time series of daily ration estimated at 3- to 4-wk intervals.
Lipid Dynamics during Reproduction in Two Livebearing Fishes, Gambusia holbrooki and Poecilia latipinna
Authors: Meffe Gary K. , Snelson Jr. Franklin F.
Published: September 2008

In animals, strategies of energy allocation among growth, maintenance and reproduction can be significantly altered by lipid storage. Poeciliid (livebearing) fishes store energy in late summer and fall for overwintering and first reproduction in spring, but details of energy use in reproduction are lacking. We conducted a laboratory experiment on the eastern mosquitofish (Gambusia holbrooki) and the sailfin molly (Poecilia latipinna) to document changes in lipid content in both the ovary and soma during development of a brood. In females of both species, ovarian lipid content was highest early in embryogeny and then declined; adult somatic lipids increased (were replenished) during embryonic development in mosquitofish, but declined in mollies. Larger clutches sequestered a larger share of body lipids in both species, possibly indicating energetic limits to reproduction. Finally, growth rate was positively correlated with somatic lipid content in both species, indicating among-individual differences in metabolic efficiency or feeding efficiency rather than a trade-off between growth and energy storage.
Patterns in the Size Structure of Littoral Zone Macroinvertebrate Communities
Authors: Rasmussen J. B.
Published: September 2008

A wide range of size spectra was encountered in 11 lakes of the Quebec Eastern Townships; most were bimodal with maximum biomass represented between 1 and 4 mg (wet weight) and between 64 and 256 mg and minimum biomass between 8 and 32 mg. PCA was used to show that the two size modes represented independent size fractions and that they were related to different environmental factors. The biomass of the small size fraction increased strongly with submerged macrophyte biomass and with lake trophic status. The biomass of the large size fraction was independent of the small size fraction and increased with wave exposure at the site. As the macrophyte biomass increased, more of the invertebrates were found upon the plants, and the small size fraction became more dominant. This is probably a result of the animals upon the vegetation being more exposed to fish predators than those hidden within the substrate. Linear regression models are developed to predict the biomass of both size fractions as well as the slope and intercept parameters of the normalized size distribution (NSD). The size-fraction approach (using PCA) complements the simpler NSD approach; it detects functionally independent size fractions in the community that NSD parameters cannot reveal.
Climate and Exceptional Fish Production off the West Coast of North America
Authors: Beamish Richard J.
Published: September 2008

From 1976 to 1978 there was a change in the climate over the North Pacific Ocean. The Aleutian Low intensified and there was a warming of the sea surface adjacent to North America and a cooling offshore. Associated with this change was a period of exceptional fish production. Strong year classes and above-average survival occurred for many commercially important species all along the west coast of Canada and the United States. Trends in total salmon catches increased primarily from increased salmon production in Alaska. Some stocks of maturing pink (Oncorhynchus gorbuscha), coho (O. kisutch), and chinook salmon (O. tshawytscha) also had above-average growth in 1977. A majority of commercially important nonsalmon species that spawned from California to the Bering Sea and have a wide range of life history types also had exceptionally strong year classes from 1976 to 1978. The exceptional survival appears to be related to improved ocean productivity caused by changes in the intensity of the Aleutian Low.
Genetic Differentiation among Populations of the Northern Redbelly Dace (Phoxinus eos) in Ontario
Authors: Toline C. Anna , Baker Allan J.
Published: September 2008

Eighteen populations of northern redbelly dace (Phoxinus eos) from three regions in Ontario were examined genetically using protein electrophoresis. Differentiation among regions was greater (FST = 0.100) than within them (FST = 0.045–0.064), suggesting that levels of gene flow are high enough to prevent differentiation through drift only within regions. Levels of heterozygosity, percent polymorphic loci, and number of alleles per locus are high relative to other fish species, which suggests that populations of dace in this study have not been subject to severe bottlenecks. Thus, population divergence has apparently occurred gradually over the last 10 000 yr. Average heterozygosity was not correlated with pond area. Thus, populations in Algonquin Park are not more prone to the effects of drift than those in the other two regions. Populations from the Sudbury region were genetically differentiated from those in Algonquin Park and from near Kingston, a result consistent with the historical biogeography of Ontario. Despite relatively high levels of heterozygosity, observed levels in this study deviated significantly from those expected from Hardy–Weinberg equilibrium. The breeding biology of P. eos and other fish suggests that our results may be explained by the presence of population substructuring in the localities sampled.
Variation in Dispersal of Galjoen (Coracinus capensis) (Teleostei: Coracinidae) from a Marine Reserve
Authors: Attwood Colin G. , Bennett Bruce A.
Published: September 2008

The dispersal of the surf-zone teleost galjoen (Coracinus capensis) from the De Hoop Marine Reserve, South Africa, was investigated. Over a period of 5.5 yr, 11 022 galjoen were tagged in the centre of the reserve. Most of the 1008 recoveries were at the site of release, while the remainder covered a distance of up to 1040 km. There was no difference with respect to age, sex, or season between those that dispersed and those that did not. Six models were developed to test the hypotheses that (1) galjoen are polymorphic with respect to dispersal behaviour, (2) nonreporting of tags masks a random dispersal process, and (3) the recovery distribution is the result of unequal movement rates in different areas. It is inferred from the likelihoods of the various models that the tagged population was polymorphic, with fish displaying either resident or nomadic behaviour. This conclusion is unaffected by a large uncertainty in the extent of nonreporting of recoveries, or by spatial variability of movement rates. The estimate of emigration from the reserve implies that the unharvested reserve population is restocking adjacent exploited areas with adult fish.
Phytoplankton Nutrient Deficiency as Related to Atmospheric Nitrogen Deposition in Northern Minnesota Acid-Sensitive Lakes
Authors: Axler Richard P. , Rose Charles , Tikkanen Craig A.
Published: September 2008

The Northern Lakes and Forests ecoregion of Minnesota contains thousands of lakes, characterized by their sensitivity to acid rain and typically low productivity. Four acid-sensitive lakes were studied from 1988 to 1991 to determine if phytoplankton were deficient in nitrogen, phosphorus, or both N and P and if the nutrient input via atmospheric deposition could increase primary production. The relative accuracy of predictions based on growth response bioassays, physiological assays, and nutrient deficiency indices was also evaluated. Our results show that (1) N enrichment generally caused a greater biomass response than P, although N + P almost always yielded the greatest effect and co-limitation was likely in two of the lakes, (2) predictions based on DIN:TP ratios generally agreed with the growth bioassays; TN:TP and DIN:SRP were not useful and could be misleading, and (3) atmospheric deposition could satisfy most of the daily algal N demand and increase the fertility of these lakes. These results suggest that although water quality protection based solely on P may not protect against this non-point source of nutrients, without these control strategies, P inputs would be expected to have a disproportionately greater stimulation of phytoplankton growth.
Translocation of 2,3,7,8-Tetrachlorodibenzo-p-dioxin from Adult Female Lake Trout (Salvelinus namaycush) to Oocytes: Effects on Early Life Stage Development and Sac Fry Survival
Authors: Walker Mary K. , Cook Philip M. , Batterman Allan R. , Butterworth Brian C. , Berini Christine , Libal John J. , Hufnagle Lawrence C. , Peterson Richard E.
Published: September 2008

There were no signs of overt toxicity in sexually mature female lake trout (Salvelinus namaycush) exposed to either a control or a 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD)-containing diet for 11 wk prior to spawning. At spawning the maternally derived egg TCDD concentrations were 42 ± 4 and 43 ± 6% of the maternal skeletal muscle TCDD concentration on a lipid and wet weight basis, respectively. Egg TCDD concentrations of 233–387 pg TCDD/g egg (wet weight) resulted in nonviable oocytes, while concentrations of 50–152 pg/g resulted in a dose-related increase in sac fry mortality associated with yolk sac edema, craniofacial alterations, and arrested development, resembling blue-sac disease. The dose–response relationship for sac fry mortality associated with blue-sac disease was essentially identical to that observed when fertilized lake trout eggs were exposed to either waterborne or injected TCDD. The no and lowest observable adverse effect levels for sac fry mortality were 23 and 50 pg/g (maternal egg exposure), 34 and 40 pg/g (waterborne egg exposure), and 44 and 55 pg/g (egg injection). LD50s, based on egg TCDD concentration, were 58 (36–90), 69 (64–75), and 80 (68–91) pg/g (95% fiducial limits) following egg exposure via maternal, waterborne, or injection routes, respectively.
Robust Regression Approach to Analyzing Fisheries Data
Authors: Chen Y. , Jackson D. A. , Paloheimo J. E.
Published: September 2008

Fisheries data often contain inaccuracies due to various errors, if such errors meet the Gauss–Markov conditions and the normality assumption, strong theoretical justification can be made for traditional least-squares (LS) estimates. However, these assumptions are not always met. Rather, it is more common that errors do not follow the Gauss–Markov and normality assumptions. Outliers may arise due to heterogenous variabilities. This results in a biased regression analysis. The sensitivity of the LS regression analysis to atypical values in the dependent and/or independent variables makes it difficult to identify outliers in a residual analysis. A robust regression method, least median squares (LMS), is insensitive to atypical values in the dependent and/or independent variables in a regression analysis. Thus, outliers that have significantly different variances from the rest of the data can be identified in a residual analysis. Using simulated and field data, we explore the application of LMS in the analysis of fisheries data. A two-step procedure is suggested in analyzing fisheries data.
Low Toxicity of the Black Fly LarvicideBacillus thuringiensisvar.israelensisto Early Stages of Brook Trout (Salvelinus fontinalis), Brown Trout (Salmo trutta), and Steelhead Trout (Oncorhynchus my kiss) following Direct and Indirect Exposure
Authors: Wipfli Mark S. , Merritt Richard W. , Taylor William W.
Published: September 2008

Mortality of brook trout (Salvelinus fontinalis), brown trout (Salmo trutta), and steelhead trout (Oncorhynchus mykiss) from eyed embryo to 82 mm fork length, exposed to Bacillus thuringiensis var. israelensis (B.t.i.) in the laboratory increased when dosages exceeded recommended rates by 12 000× or more. There was generally no toxicity difference between denatured (autoclaved) and nondenatured B.t.i. for all three trout species at all B.t.i. concentrations tested, indicating that mortality was due to formulation components and not B.t.i. toxin. The 48-h LC50values for brown and brook trout alevins ranged from 1561 to 2321 ppm for both denatured and nondenatured B.t.i. Scanning electron micrographs showed particle and mucus accumulation on gill surfaces from fish exposed to 2000 ppm B.t.i. for 4 h. Oxygen and carbon dioxide levels in blood from exposed (4000 ppm B.t.i. for 4 h) and unexposed fish were similar. Brown trout of 43 mm fork length fed excess B.t.i.-killed or live black flies (Cnephia dacotensis) ate similar quantities of each larval type, and both groups experienced similar mortalities and growth rates at 30-d postexposure.
Stimulation of β3-adrenoceptors relaxes rat urinary bladder smooth muscle via activation of the large-conductance Ca2+-activated K+ channels
Authors: Hristov Kiril L. , Cui Xiangli , Brown Sean M. , Liu Lei , Kellett Whitney F. , Petkov Georgi V.
Published: September 2008

We investigated the role of large-conductance Ca2+-activated K+ (BK) channels in β3-adrenoceptor (β3-AR)-induced relaxation in rat urinary bladder smooth muscle (UBSM). BRL 37344, a specific β3-AR agonist, inhibits spontaneous contractions of isolated UBSM strips. SR59230A, a specific β3-AR antagonist, and H89, a PKA inhibitor, reduced the inhibitory effect of BRL 37344. Iberiotoxin, a specific BK channel inhibitor, shifts the BRL 37344 concentration response curves for contraction amplitude, net muscle force, and tone to the right. Freshly dispersed UBSM cells and the perforated mode of the patch-clamp technique were used to determine further the role of β3-AR stimulation by BRL 37344 on BK channel activity. BRL 37344 increased spontaneous, transient, outward BK current (STOC) frequency by 46.0 ± 20.1%. In whole cell mode at a holding potential of Vh = 0 mV, the single BK channel amplitude was 5.17 ± 0.28 pA, whereas in the presence of BRL 37344, it was 5.55 ± 0.41 pA. The BK channel open probability was also unchanged. In the presence of ryanodine and nifedipine, the current-voltage relationship in response to depolarization steps in the presence and absence of BRL 37344 was identical. In current-clamp mode, BRL 37344 caused membrane potential hyperpolarization from −26.1 ± 2.1 mV (control) to −29.0 ± 2.2 mV. The BRL 37344-induced hyperpolarization was eliminated by application of iberiotoxin, tetraethylammonium or ryanodine. The data indicate that stimulation of β3-AR relaxes rat UBSM by increasing the BK channel STOC frequency, which causes membrane hyperpolarization and thus relaxation.
PKC phosphorylation modulates PKA-dependent binding of the R domain to other domains of CFTR
Authors: Seavilleklein Gage , Amer Noha , Evagelidis Alexandra , Chappe Frédéric , Irvine Thomas , Hanrahan John W. , Chappe Valérie
Published: September 2008

Activity of the CFTR channel is regulated by phosphorylation of its regulatory domain (RD). In a previous study, we developed a bicistronic construct called ΔR-Split CFTR, which encodes the front and back halves of CFTR as separate polypeptides without the RD. These fragments assemble to form a constitutively active CFTR channel. Coexpression of the third fragment corresponding to the missing RD restores regulation by PKA, and this is associated with dramatically enhanced binding of the phosphorylated RD. In the present study, we examined the effect of PKC phosphorylation on this PKA-induced interaction. We report here that PKC alone enhanced association of the RD with ΔR-Split CFTR and that binding was further enhanced when the RD was phosphorylated by both kinases. Mutation of all seven PKC consensus sequences on the RD (7CA-RD) did not affect its association under basal (unphosphorylated) conditions but abolished phosphorylation-induced binding by both kinases. Iodide efflux responses provided further support for the essential role of RD binding in channel regulation. The basal activity of ΔR-Split/7CA-RD channels was similar to that of ΔR-Split/wild type (WT)-RD channels, whereas cAMP-stimulated iodide efflux was greatly diminished by removal of the PKC sites, indicating that 7CA-RD binding maintains channels in an inactive state that is unresponsive to PKA. These results suggest a novel mechanism for CFTR regulation in which PKC modulates PKA-induced domain-domain interactions.
Primary granule exocytosis in human neutrophils is regulated by Rac-dependent actin remodeling
Authors: Mitchell Troy , Lo Andrea , Logan Michael R. , Lacy Paige , Eitzen Gary
Published: September 2008

The actin cytoskeleton regulates exocytosis in all secretory cells. In neutrophils, Rac2 GTPase has been shown to control primary (azurophilic) granule exocytosis. In this report, we propose that Rac2 is required for actin cytoskeletal remodeling to promote primary granule exocytosis. Treatment of neutrophils with low doses (≤10 μM) of the actin-depolymerizing drugs latrunculin B (Lat B) or cytochalasin B (CB) enhanced both formyl peptide receptor- and Ca2+ ionophore-stimulated exocytosis. Higher concentrations of CB or Lat B, or stabilization of F-actin with jasplakinolide (JP), inhibited primary granule exocytosis measured as myeloperoxidase release but did not affect secondary granule exocytosis determined by lactoferrin release. These results suggest an obligatory role for F-actin disassembly before primary granule exocytosis. However, lysates from secretagogue-stimulated neutrophils showed enhanced actin polymerization activity in vitro. Microscopic analysis showed that resting neutrophils contain significant cortical F-actin, which was redistributed to sites of primary granule translocation when stimulated. Exocytosis and actin remodeling was highly polarized when cells were primed with CB; however, polarization was reduced by Lat B preincubation, and both polarization and exocytosis were blocked when F-actin was stabilized with JP. Treatment of cells with the small molecule Rac inhibitor NSC23766 also inhibited actin remodeling and primary granule exocytosis induced by Lat B/fMLF or CB/fMLF, but not by Ca2+ ionophore. Therefore, we propose a role for F-actin depolymerization at the cell cortex coupled with Rac-dependent F-actin polymerization in the cell cytoplasm to promote primary granule exocytosis.