bluuebunny/crossref_metadata_2025 huggingface dataset:
Persistent Currents in Normal Metal Rings
Authors: Bleszynski-Jayich A. C. , Shanks W. E. , Peaudecerf B. , Ginossar E. , von Oppen F. , Glazman L. , Harris J. G. E.
Published: October 2009

Normally Persistent

In superconductors, currents are expected to flow persistently without dissipation. Quantum mechanics predicts that such persistent currents should also exist in normal mesoscopic metal rings. However, the predicted effect is small, which has made the detection of these currents difficult.

Bleszynski-Jayich
et al.

(p.
272
; see the Perspective by

Birge

) have developed a sensitive technique based on a nanomechanical resonator. An array of aluminum rings on the end of a resonator was fabricated to monitor the shift in frequency of the resonator as the rings were threaded with quanta of magnetic-field flux, setting up currents in the rings. In agreement with a theoretical scenario put forward over a decade ago, the results could be described with a model based on non-interacting electrons.
Arterial-Venous Segregation by Selective Cell Sprouting: An Alternative Mode of Blood Vessel Formation
Authors: Herbert Shane P. , Huisken Jan , Kim Tyson N. , Feldman Morri E. , Houseman Benjamin T. , Wang Rong A. , Shokat Kevan M. , Stainier Didier Y. R.
Published: October 2009

Making Split Decisions

Development of the vertebrate vasculature has been thought to involve just two mechanisms of blood vessel formation.

Herbert
et al.

(p.
294
; see the Perspective by

Benedito and Adams

) identified a third mechanism in zebrafish in which two distinct, unconnected vessels can be derived from a single precursor vessel. Several vascular endothelial growth factors and signaling pathways, including ephrin and notch signaling, coordinated the sorting and segregation of a mixture of arterial and venous-fated precursor cells into distinct arterial and venous vessels. These findings provide a mechanistic framework for how mixed populations of cells can coordinate their behavior to segregate and form distinct blood vessels.
'Omics Data Sharing
Authors: Field Dawn , Sansone Susanna-Assunta , Collis Amanda , Booth Tim , Dukes Peter , Gregurick Susan K. , Kennedy Karen , Kolar Patrik , Kolker Eugene , Maxon Mary , Millard Siân , Mugabushaka Alexis-Michel , Perrin Nicola , Remacle Jacques E. , Remington Karin , Rocca-Serra Philippe , Taylor Chris F. , Thorley Mark , Tiwari Bela , Wilbanks John
Published: October 2009

Data sharing, and the good annotation practices it depends on, must become part of the fabric of daily research for researchers and funders.
Nuclear Power for Axonal Growth
Authors: Subang M. C. , Richardson P. M.
Published: October 2009

A transcription factor involved in oncogenesis and stem cell biology also controls neuronal axon outgrowth.
Comprehensive Mapping of Long-Range Interactions Reveals Folding Principles of the Human Genome
Authors: Lieberman-Aiden Erez , van Berkum Nynke L. , Williams Louise , Imakaev Maxim , Ragoczy Tobias , Telling Agnes , Amit Ido , Lajoie Bryan R. , Sabo Peter J. , Dorschner Michael O. , Sandstrom Richard , Bernstein Bradley , Bender M. A. , Groudine Mark , Gnirke Andreas , Stamatoyannopoulos John , Mirny Leonid A. , Lander Eric S. , Dekker Job
Published: October 2009

Chromosomal Mapping

The conformation of the genome in the nucleus and contacts between both proximal and distal loci influence gene expression. In order to map genomic contacts,

Lieberman-Aiden
et al.

(p.
289
, see the cover) developed a technique to allow the detection of all interactions between genomic loci in the eukaryotic nucleus followed by deep sequencing. This technology was used to map the organization of the human genome and to examine the spatial proximity of chromosomal loci at one megabase resolution. The map suggests that the genome is partitioned into two spatial compartments that are related to local chromatin state and whose remodeling correlates with changes in the chromatin state.
Chronic Fatigue and Prostate Cancer: A Retroviral Connection?
Authors: Kean Sam
Published: October 2009

As if chronic fatigue syndrome (CFS) hasn't caused enough brawls, a new study published online by
Science
links the disease to a possibly contagious rodent retrovirus, XMRV, which has also been implicated in an aggressive form of prostate cancer.
Agricultural Science Gets More Money, New Faces
Authors: Stokstad Erik
Published: October 2009

After decades of flat funding, agricultural research seems to have caught the attention of U.S. policymakers, as Congress gave a 30% boost to the main competitive grants program of the U.S. Department of Agriculture (USDA), raising it to $263 million for 2010.
Both of the World's Ice Sheets May Be Shrinking Faster and Faster
Authors: Kerr Richard A.
Published: October 2009

The two great ice sheets—Greenland's and Antarctica's—have had plenty of press lately, what with galloping glaciers and whole lakes of meltwater plunging into ice holes in minutes. Surveys of ice-sheet volume made from planes and satellites have quantified these losses, but those assessments have been spotty in time, space, or both.
For a Famous Physics Laboratory, A Quick and Painful Rebirth
Authors: Cho Adrian
Published: October 2009

Renowned for particle physics experiments, SLAC National Accelerator Laboratory has reinvented itself as a multipurpose lab featuring the world's first x-ray laser.
New Work May Complicate History Of Neandertals and
H. sapiens
Authors: Balter Michael
Published: October 2009

At a meeting on human origins, held this month in Gibraltar, bones in a Spanish cave and stone tools in Asia sparked controversial new ideas about human evolution and migration.
Droplet-Scale Estrogen Assays in Breast Tissue, Blood, and Serum
Authors: Mousa Noha A. , Jebrail Mais J. , Yang Hao , Abdelgawad Mohamed , Metalnikov Pavel , Chen Jian , Wheeler Aaron R. , Casper Robert F.
Published: October 2009

A digital electrode array, on which drops of solvent can be electronically manipulated, allows automated steroid extraction from tiny tissue samples for diagnosis or research.
Population Structure of
Staphylococcus aureus
Strains Isolated from Intensive Care Unit Patients in The Netherlands over an 11-Year Period (1996 to 2006)
Authors: Rijnders M. I. A. , Deurenberg R. H. , Boumans M. L. L. , Hoogkamp-Korstanje J. A. A. , Beisser P. S. , Stobberingh E. E.
Published: October 2009

The genetic background and the presence of several virulence factors of
Staphylococcus aureus
isolates from intensive care unit (ICU) patients from 14 hospitals in The Netherlands isolated from 1996 until 2006 were investigated. In total, 936 methicillin-susceptible
S. aureus
(MSSA) and 7 methicillin-resistant
S. aureus
(MRSA) isolates were collected. The genetic background was determined by
spa
typing and multilocus sequence typing (MLST). The virulence determinants Panton-Valentine leukocidin (PVL), toxic shock syndrome toxin 1 (TSST-1), and collagen adhesion (CNA) were detected with real-time PCR assays. On the MRSA isolates, mobile resistance staphylococcal cassette chromosome
mec
(SCC
mec
) typing was performed. Among the MSSA isolates, 313 different
spa
types were observed. A genetic background common to MRSA clones, e.g., MLST clonal complex 1 (CC1), CC5, CC8, CC22, CC30, and CC45, was observed among 62% of the isolates. The remaining isolates were associated with MSSA-related MLST CCs. MLST CC1, CC25, and CC30 were continuously present, and other MLST CCs fluctuated over time. Two percent of the MSSA isolates harbored PVL, 21% had TSST-1, and 46% were positive for CNA. There were no changes in the prevalence of the virulence factors over time. Four MRSA isolates were typed as ST8-MRSA-IV (where ST is the MLST sequence type and IV is the SCC
mec
type), two were ST5-MRSA-II, and one was ST228-MRSA-I. All MRSA isolates were PVL, CNA, and TSST-1 negative except for the two ST5-MRSA-II isolates, which were TSST-1 positive. No changes in the
S. aureus
genetic background and the prevalence of the virulence factors PVL, CNA, and TSST-1 were observed in ICU patients in The Netherlands over time.
Infective Endocarditis Due to
Citrobacter koseri
in an Immunocompetent Adult
Authors: Dzeing-Ella A. , Szwebel T. A. , Loubinoux J. , Coignard S. , Bouvet A. , Le Jeunne C. , Aslangul E.
Published: October 2009

Citrobacter koseri
(formerly
C
itrobacter
diversus
) is a motile gram-negative bacillus usually arising from urinary and gastrointestinal tracts.
C. koseri
rarely causes infection in immunocompetent patients and, thus far, has been considered an opportunistic pathogen. We report on a 30-year-old man, with no medical past, hospitalized for infective aortic endocarditis due to
C. koseri
. Four weeks of antibiotherapy led to a full recovery for this patient. However, this case is unusual, as previous history and 1 year of follow-up showed no features of intercurrent immunosuppression. Microbiological diagnosis was based on using 16S rRNA gene sequencing.
Acquisition of High-Level Mupirocin Resistance and Its Fitness Cost among Methicillin-Resistant
Staphylococcus aureus
Strains with Low-Level Mupirocin Resistance
Authors: Mongkolrattanothai Kanokporn , Pumfrey Lisa , Mankin Peggy , Gray Barry M.
Published: October 2009

We investigated whether methicillin (meticillin)-resistant
Staphylococcus aureus
(MRSA) isolates with low-level mupirocin resistance can serve as recipients of a pSK41-like plasmid conferring high-level mupirocin resistance without substantial fitness cost. Our results suggest that acquisition of the plasmid conferring high-level mupirocin resistance was not necessarily associated with fitness cost in some MRSA recipients with low-level mupirocin resistance.
Prevalence of ST9 Methicillin-Resistant
Staphylococcus aureus
among Pigs and Pig Handlers in Malaysia
Authors: Neela Vasanthakumari , Mohd Zafrul Arif , Mariana Nor Shamsudin , van Belkum Alex , Liew Yun Khoon , Rad Ehsanollah Ghaznavi
Published: October 2009

Methicillin-resistant
Staphylococcus aureus
(MRSA) of sequence type 398 (ST398) has frequently been detected in pigs and pig handlers. However, in Malaysia, sampling 360 pigs and 90 pig handlers from 30 farms identified novel ST9-
spa
type t4358-staphylococcal cassette chromosome
mec
type V MRSA strains that were found to transiently colonize more than 1% of pigs and 5.5% of pig handlers.
Evaluation of Three Commercial Broth Media for Pigment Detection and Identification of a Group B
Streptococcus
(
Streptococcus agalactiae
)
Authors: Carvalho Maria da Glória , Facklam Richard , Jackson Delois , Beall Bernard , McGee Lesley
Published: October 2009

Detection of group B
Streptococcus
(GBS) strains at various bacterial concentrations was evaluated using three pigment-producing broth media. At 10
3
CFU/ml, StrepB carrot broth (SBCB), Granada instant liquid biphasic (IGLB), and Northeast Laboratory GBS screening medium (NEL-GBS) showed 100% detection, but at the lower bacterial counts, SBCB and IGLB were more sensitive than NEL-GBS after 24 h.
First Descriptions of
bla
KPC
in
Raoultella
spp. (
R. planticola
and
R. ornithinolytica
): Report from the SENTRY Antimicrobial Surveillance Program
Authors: Castanheira Mariana , Deshpande Lalitagauri M. , DiPersio Joseph R. , Kang Julia , Weinstein Melvin P. , Jones Ronald N.
Published: October 2009

Two strains of
Raoultella planticola
and one of
Raoultella ornithinolytica
showing carbapenem resistance were recovered from patients hospitalized in New Jersey and Ohio. All patients had received previous antimicrobial treatment, including carbapenems. These strains harbored
bla
KPC-2
and
bla
KPC-3
. Carbapenemase genes were embedded in isoforms of Tn
4401
and were plasmidic and chromosomal in location.
Hemagglutinin-Dependent Tropism of H5N1 Avian Influenza Virus for Human Endothelial Cells
Authors: Ocaña-Macchi Manuela , Bel Michael , Guzylack-Piriou Laurence , Ruggli Nicolas , Liniger Matthias , McCullough Kenneth C. , Sakoda Yoshihiro , Isoda Norikazu , Matrosovich Mikhail , Summerfield Artur
Published: October 2009

Although current H5N1 highly pathogenic avian influenza viruses (HPAIV) are inefficiently transmitted to humans, infected individuals can suffer from severe disease, often progressing rapidly to acute respiratory distress syndrome and multiorgan failure. This is in contrast with the situation with human influenza viruses, which in immunocompetent individuals usually cause only a respiratory disease which is less aggressive than that observed with avian H5N1 viruses. While the biological basis of inefficient transmission is well documented, the mechanisms by which the H5N1 viruses cause fatal disease remain unclear. In the present study, we demonstrate that human pulmonary microvascular endothelial cells (hPMEC) had a clearly higher susceptibility to infection by H5N1 HPAIV than to infection by human influenza viruses. This was measurable by de novo intracellular nucleoprotein production and virus replication. It was also related to a relatively higher binding capacity to cellular receptors. After infection of hPMEC, cell activation markers E-selectin and P-selectin were upregulated, and the proinflammatory cytokines interleukin-6 and beta interferon were secreted. H5N1 virus infection was also associated with an elevated rate of cell death. Reverse genetics analyses demonstrated a major role for the viral hemagglutinin in this cell tropism. Overall, avian H5N1 viruses have a particular receptor specificity targeting endothelial cells that is different from human influenza viruses, and this H5N1 receptor specificity could contribute to disease pathogenesis.
Binding of Herpes Simplex Virus Glycoprotein B (gB) to Paired Immunoglobulin-Like Type 2 Receptor α Depends on Specific Sialylated O
-
Linked Glycans on gB
Authors: Wang Jing , Fan Qing , Satoh Takeshi , Arii Jun , Lanier Lewis L. , Spear Patricia G. , Kawaguchi Yasushi , Arase Hisashi
Published: October 2009

Paired immunoglobulin-like type 2 receptor α (PILRα) is an inhibitory receptor expressed on both hematopoietic and nonhematopoietic cells. Its binding to a cellular ligand, CD99, depends on the presence of sialylated O
-
linked glycans on CD99. Glycoprotein B (gB) of herpes simplex virus type 1 (HSV-1) binds to PILRα, and this association is involved in HSV-1 infection. Here, we found that the presence of sialylated O
-
glycans on gB is required for gB to associate with PILRα. Furthermore, we identified two threonine residues on gB that are essential for the addition of the principal O
-
glycans acquired by gB and that are also essential for the binding of PILRα to gB.
The Canine Papillomavirus E5 Protein Signals from the Endoplasmic Reticulum
Authors: Condjella Rachel , Liu Xuefeng , Suprynowicz Frank , Yuan Hang , Sudarshan Sawali , Dai Yuhai , Schlegel Richard
Published: October 2009

The recently discovered
Canis familiaris
papillomavirus (PV) type 2 (CfPV2) provides a unique opportunity to study PV gene functions in vitro and in vivo. Unlike the previously characterized canine oral PV, CfPV2 contains an E5 open reading frame and is associated with progression to squamous cell carcinoma. In the current study, we have expressed and characterized the CfPV2-encoded E5 protein, a small, hydrophobic, 41-amino-acid polypeptide. We demonstrate that, similar to the E5 protein from high-risk human PV type 16, the CfPV2 E5 protein is localized in the endoplasmic reticulum (ER) and that its expression decreases keratinocyte proliferation and cell life span. E5 expression also increases the percentage of cells in the G
1
phase of the cell cycle, with a concomitant decrease in the percentage of cells in S phase. To identify a potential mechanism for E5-mediated growth inhibition from the ER, we developed a real-time PCR method to quantify the splicing of XBP1 mRNA as a measure of ER stress. We found that the CfPV2 E5 protein induced ER stress and that this, as well as the observed growth inhibition, is tempered significantly by coexpression of the CfPV2 E6 and E7 genes. It is possible that the spatial/temporal regulation of E6/E7 gene expression during keratinocyte differentiation might therefore modulate E5 activity and ER stress.
Hepatitis C Virus (HCV) Proteins Induce NADPH Oxidase 4 Expression in a Transforming Growth Factor β-Dependent Manner: a New Contributor to HCV-Induced Oxidative Stress
Authors: Boudreau Howard E. , Emerson Suzanne U. , Korzeniowska Agnieszka , Jendrysik Meghan A. , Leto Thomas L.
Published: October 2009

Viral hepatitis-induced oxidative stress accompanied by increased levels of transforming growth factor β (TGF-β) and hepatic fibrosis are hallmarks of hepatitis C virus (HCV) infection. The mechanisms of redox regulation in the pathogenesis of HCV-induced liver disease are not clearly understood. The results of our current studies suggest that reactive oxygen species (ROS) derived from Nox4, a member of the NADPH oxidase (Nox) family, could play a role in HCV-induced liver disease. We found that the expression of HCV (genotype 1a) cDNA constructs (full-length and subgenomic), core protein alone, viral RNA, or replicating HCV (JFH-AM2) induced Nox4 mRNA expression and ROS generation in human hepatocyte cell lines (Huh-7, Huh-7.5, HepG2, and CHL). Conversely, hepatocytes expressing Nox4 short hairpin RNA (shRNA) or an inactive dominant negative form of Nox4 showed decreased ROS production when cells were transfected with HCV. The promoters of both human and murine Nox4 were used to demonstrate transcriptional regulation of Nox4 mRNA by HCV, and a luciferase reporter tied to an ∼2-kb promoter region of Nox4 identified HCV-responsive regulatory regions modulating the expression of Nox4. Furthermore, the human Nox4 promoter was responsive to TGF-β1, and the HCV core-dependent induction of Nox4 was blocked by antibody against TGF-β or the expression of dominant negative TGF-β receptor type II. These findings identified HCV as a regulator of Nox4 gene expression and subsequent ROS production through an autocrine TGF-β-dependent mechanism. Collectively, these data provide evidence that HCV-induced Nox4 contributes to ROS production and may be related to HCV-induced liver disease.
Early, Active, and Specific Localization of Herpes Simplex Virus Type 1 gM to Nuclear Membranes
Authors: Zhang Jie , Nagel Claus-Henning , Sodeik Beate , Lippé Roger
Published: October 2009

Thirteen different glycoproteins are incorporated into mature herpes simplex virus type 1 (HSV-1) virions. Five of them play important roles during entry, while others intervene during egress of the virus. Although HSV-1 gM is not essential in cell culture, its deletion reduces viral yields and promotes syncytium formation. Furthermore, gM is conserved among herpesviruses, is essential for several of them, and can redirect the gD and gH/gL viral glycoproteins from the cell surface to the
trans
-Golgi network, where gM presumably modulates final capsid envelopment. Late in infection, gM reaches the nuclear envelope and decorates perinuclear virions. This process seemingly requires U
L
31 and U
L
34 and occurs when several markers of the
trans
-Golgi network have relocalized to the nucleus. However, the precise mechanism of gM nuclear targeting is unclear. We now report that gM is quickly and specifically targeted to nuclear membranes in a virus-dependent manner. This occurs prior to the HSV-1-induced reorganization of the
trans
-Golgi network and before gM enters the secretory pathway. The presence of a high-mannose glycosylation pattern on gM further corroborated these findings. While gM was targeted to the inner nuclear membrane early in infection, its partners gD, gH, gN, VP22, U
L
31, and U
L
34 did not colocalize with gM. These data suggest that nuclear gM fulfills an early nuclear function that is independent of its known interaction partners and its function in viral egress.
Characterization of Viral and Human RNAs Smaller than Canonical MicroRNAs
Authors: Li Zhihua , Kim Sang Woo , Lin Yuefeng , Moore Patrick S. , Chang Yuan , John Bino
Published: October 2009

Recently identified small (20 to 40 bases) RNAs, such as microRNAs (miRNAs) and endogenous small interfering RNAs (siRNAs) participate in important cellular pathways. In this report, we systematically characterized several novel features of human and viral RNA products smaller than miRNAs. We found that Kaposi sarcoma-associated herpesvirus K12-1 miRNA (23 bases) associates with a distinct, unusually small (17-base) RNA (usRNA) that can effectively downregulate a K12-1 miRNA target, human
RAD21
, suggesting that stable degradation-like products may also contribute to gene regulation. High-throughput sequencing reveals a diverse set of human miRNA-derived usRNAs and other non-miRNA-derived usRNAs. Human miRNA-derived usRNAs preferentially match to 5′ ends of miRNAs and are also more likely to associate with the siRNA effector protein Ago2 than with Ago1. Many non-miRNA-derived usRNAs associate with Ago proteins and also frequently contain C-rich 3′-specific motifs that are overrepresented in comparison to Piwi-interacting RNAs and transcription start site-associated RNAs. We postulate that approximately 30% of usRNAs could have evolved to participate in biological processes, including gene silencing.
A New Genetic Vaccine Platform Based on an Adeno-Associated Virus Isolated from a Rhesus Macaque
Authors: Lin Jianping , Calcedo Roberto , Vandenberghe Luk H. , Bell Peter , Somanathan Suryanarayan , Wilson James M.
Published: October 2009

We created a hybrid adeno-associated virus (AAV) from two related rhesus macaque isolates, called AAVrh32.33, and evaluated it as a vaccine carrier for human immunodeficiency virus type 1 (HIV-1) and type A influenza virus antigens. The goal was to overcome the limitations of vaccines based on other AAVs, which generate dysfunctional T-cell responses and are inhibited by antibodies found in human sera. Injection of a Gag-expressing AAVrh32.33 vector into mice resulted in a high-quality CD8
+
T-cell response. The resulting Gag-specific T cells express multiple cytokines at high levels, including interleukin-2, with many having memory phenotypes; a subsequent boost with an adenovirus vector yielded a brisk expansion of Gag-specific T cells. A priming dose of AAVrh32.33 led to high levels of Gag antibodies, which exceed levels found after injection of adenovirus vectors. Importantly, passive transfer of pooled human immunoglobulin into mice does not interfere with the efficacy of AAVrh32.33 expressing nucleoproteins from influenza virus, as measured by protection to a lethal dose of influenza virus, which is consistent with the very low seroprevalence to this virus in humans. Studies of macaques with vectors expressing gp140 from HIV-1 (i.e., with AAVrh32.33 as the prime and simian adenovirus type 24 as the boost) demonstrated results similar to those for mice with high-level and high-quality CD8
+
T-cell responses to gp140 and high-titered neutralizing antibodies to homologous HIV-1. The biology of this novel AAV hybrid suggests that it should be a preferred genetic vaccine carrier, capable of generating robust T- and B-cell responses.
High Frequencies of Virus-Specific CD8+T-Cell Precursors
Authors: Seedhom Mina O. , Jellison Evan R. , Daniels Keith A. , Welsh Raymond M.
Published: October 2009

A productive CD8+T-cell response to a viral infection requires rapid division and proliferation of virus-specific CD8+T cells. Tetramer-based enrichment assays have recently given estimates of the numbers of peptide-major histocompatibility complex-specific CD8+T cells in naïve mice, but precursor frequencies for entire viruses have been examined only by using in vitro limiting-dilution assays (LDAs). To examine CD8+T-cell precursor frequencies for whole viruses, we developed an in vivo LDA and found frequencies of naïve CD8+T-cell precursors of 1 in 1,444 for vaccinia virus (VV) (∼13,850 VV-specific CD8+T cells per mouse) and 1 in 2,958 for lymphocytic choriomeningitis virus (LCMV) (∼6,761 LCMV-specific CD8+T cells per mouse) in C57BL/6J mice. In mice immune to VV, the number of VV-specific precursors, not surprisingly, dramatically increased to 1 in 13 (∼1,538,462 VV-specific CD8+T cells per mouse), consistent with estimates of VV-specific memory T cells. In contrast, precursor numbers for LCMV did not increase in VV-immune mice (1 in 4,562, with ∼4,384 LCMV-specific CD8+T cells per VV-immune mouse). Using H-2Db-restricted LCMV GP33-specific P14-transgenic T cells, we found that, after donor T-cell take was accounted for, approximately every T cell transferred underwent a full proliferative expansion in response to LCMV infection. This high efficiency was also seen with memory populations, suggesting that most antigen-specific T cells will proliferate extensively at a limiting dilution in response to infections. These results show that frequencies of naïve and memory CD8+T cell precursors for whole viruses can be remarkably high.
Characterization of a Newly Identified 35-Amino-Acid Component of the Vaccinia Virus Entry/Fusion Complex Conserved in All Chordopoxviruses
Authors: Satheshkumar P. S. , Moss Bernard
Published: October 2009

The original annotation of the vaccinia virus (VACV) genome was limited to open reading frames (ORFs) of at least 65 amino acids. Here, we characterized a 35-amino-acid ORF (O3L) located between ORFs O2L and I1L. ORFs similar in length to O3L were found at the same genetic locus in all vertebrate poxviruses. Although amino acid identities were low, the presence of a characteristic N-terminal hydrophobic domain strongly suggested that the other poxvirus genes were orthologs. Further studies demonstrated that the O3 protein was expressed at late times after infection and incorporated into the membrane of the mature virion. An O3L deletion mutant was barely viable, producing tiny plaques and a 3-log reduction in infectious progeny. A mutant VACV with a regulated O3L gene had a similar phenotype in the absence of inducer. There was no apparent defect in virus morphogenesis, though O3-deficient virus had low infectivity. The impairment was shown to be at the stage of virus entry, as cores were not detected in the cytoplasm after virus adsorption. Furthermore, O3-deficient virus did not induce fusion of infected cells when triggered by low pH. These characteristics are hallmarks of a group of proteins that form the entry/fusion complex (EFC). Affinity purification experiments demonstrated an association of O3 with EFC proteins. In addition, the assembly or stability of the EFC was impaired when expression of O3 was repressed. Thus, O3 is the newest recognized component of the EFC and the smallest VACV protein shown to have a function.
Differential Response to Water Current by Two Homozygous LDH Phenotypes of Young Rainbow Trout (Salmo gairdneri)
Authors: Northcote T. G. , Kelso B. W.
Published: October 2009

Above-waterfall, wild stocks of rainbow trout fry homozygous for liver lactate dehydrogenase alleles ldh HαA and ldh HαB were artificially propagated, and their response to water current was compared in experimental channels permitting upstream or downstream movement. Although HαA HαA phenotypes showed significantly more upstream movement than HαB HαB phenotypes in tests made under lighted conditions and less downstream movement in darkness, these differences in behavior cannot necessarily be ascribed to the ldh Hα locus. Implications to control of current responses in trout maintaining populations above waterfalls impassible to upstream migration are discussed.Key words: current response, LDH, rainbow trout, migratory behavior
Shifts In Aquatic Insect Populations In A First-Order Southern Appalachian Stream Following A Decade Of Old Field Succession
Authors: Haefner John D. , Wallace J. Bruce
Published: October 2009

Aquatic insects of two first-order southern Appalachian streams were sampled monthly during one year. Sawmill Branch Watershed was subjected to several disturbances before 1968, including clear-cutting. Since 1968 Sawmill Branch Watershed has undergone natural secondary succession from terrestrial vegetation dominated by Gramineae to a herbaceous/coppice hardwood dominated by black locust, Robinia pseudoacacia. Grady Branch, the control stream, drains an undisturbed hardwood watershed. Aquatic insect densities on Sawmill Branch were about twice those of Grady Branch, which represent a dramatic reversal from results obtained by a similar study in 1968. It is suggested that change in riparian vegetation is a major factor influencing long-term changes in aquatic insect populations, and these changes are manifested through a shift toward an allochthonous energy base. The most conspicuous changes in macrobenthos on the disturbed watershed between 1968 and 1978 were a reduction in grazer organisms and a corresponding increase in shredder organisms, especially Peltoperla (Plecoptera).Key words: macrobenthos, secondary succession, watershed changes, clear-cutting, allochthonous detritus, food quality.
Methyl Mercury Levels in a Polluted Prairie River–Lake System: Seasonal and Site-Specific Variations, and the Dominant Influence of Trophic Conditions
Authors: Jackson Togwell A.
Published: October 2009

The Moose Jaw River – Qu'Appelle River system of southern Saskatchewan (Canada) and its chain of hypertrophic lakes are polluted with mercury (Hg) and sewage from urban point-sources. Analysis of water, suspended particles, and bottom sediments sampled at different localities at different times of year (from April to November) revealed that methyl mercury (CH3Hg+) levels are not controlled by the total abundance of inorganic Hg but are highly dependent on the abundance of organic matter and planktonic algae. CH3Hg+ levels were anomalously high in the presence of sewage effluents and associated algal blooms and at times of reduced river discharge, when the flushing and dilution of nutrients were minimal. At elevated organic carbon, nitrogen, and chlorophyll concentrations, CH3Hg+ levels were high even if inorganic Hg levels were low; but at low organic carbon, nitrogen, and chlorophyll concentrations, CH3Hg+ levels were low even if inorganic Hg levels were high. The results are ascribed principally to stimulation of the activities of Hg-methylating microorganisms by organic nutrients from algae and sewage. The possibility of amerliorating the Hg problem by reducing nutrient pollution is discussed.
A New View of the Predation Cycle of a Planktivorous Fish, White Crappie (Pomoxis annularis)
Authors: O'Brien W. John , Evans Barbara I. , Howick Gregory L.
Published: October 2009

Predators are often categorized as either cruise or ambush feeding strategists. We present evidence that white crappie (Pomoxis annularis) are neither. Instead, the crappie swim intermittently and search only when stationary. If the crappie searched while swimming, one would expect the run speeds to be slower than the pursuit speeds, but no difference was found between these two measurements. Assuming that prey are located while swimming, a foreshortening of runs prior to pursuit would also be expected, but again, none was detectable. The duration of the search pause appears to be related to the detectability of the prey. Crappie also search during the pause immediately following the attack and ingestion of a prey item. The observation that the probabilities of detecting and pursuing a prey following a run or an attack do not differ significantly supports this conclusion. Also, the duration of the pause following a run or attack does not differ significantly over a wide range of temperatures. If these views are correct, white crappie could not forage optimally by either deleting located prey items from the diet or minimizing handling time. What they appear to be doing is creatively managing their search time.
Patterns in Biomass and Cover of Aquatic Macrophytes in Lakes
Authors: Duarte Carlos M. , Kalff Jacob , Peters Robert H.
Published: October 2009

A quantitative analysis of biomass and cover of both submerged and emergent macrophytes in 139 lakes reported in the literature revealed that biomass and cover of emergent macrophytes are, on average, proportional to the lake area, but that the biomass and cover of submerged plants are proportionally reduced with increasing lake size. Underwater light was found to be the best descriptor of the cover and biomass of submerged plants. Conversely, emergent macrophytes are most strongly affected by lake morphometry, and in particular by its average slope. The predictability of the abundance of emergent and submerged macrophytes from these environmental factors stresses the predominant role that they play in macrophyte ecology and confirms the existence of strong patterns in the abundance of aquatic plants worldwide.
Impact of Atrazine on Periphyton in Freshwater Enclosures and Some Ecological Consequences
Authors: Herman David , Kaushik Narinder K. , Solomon Keith R.
Published: October 2009

The herbicide atrazine inhibited production of periphyton within limnocorrals (in situ aquatic enclosures) and altered the composition of the periphyton community. On two occasions, 6 wk apart, three limnocorrals were treated with a surface application of atrazine equivalent to a nominal enclosure concentration of 100 μg∙L−1 During the first atrazine pulse, the Cyanophyta disappeared and organic matter decreased to values significantly less than those within three control enclosures. Within 3 wk of the second atrazine application, a 36–67% reduction in organic matter, chlorophyll, and algal biomass and a significant decrease in the rate of carbon assimilation were evident. These events coincided with a decrease in number of certain Chlorophyta species, although other Chlorophyta species increased in number. The Bacillariophyceae maintained biomass levels greater than those in the controls for 9 wk after the second atrazine application. Total limnocorral periphyton production was greater than that of the phytoplankton after 5–10 wk of periphyton colonization in both the control and atrazine limnocorrals.
Experimental Analysis of the Direct and indirect Effects of an Omnivorous Filter-Feeding Clupeid on Plankton Community Structure
Authors: Drenner Ray W. , Threlkeld Stephen T. , McCracken Michael D.
Published: October 2009

In laboratory trials, feeding rates of an omnivorous filter-feeding clupeid, Dorosoma cepedianum, increased as a function of particle size, with maximal rates on microspheres, spherical algae, and Zooplankton >40 μm; it did not efficiently feed on filamentous Anabaena flos-aquae. To examine the community level impacts of Dorosoma, we conducted four seasonal outdoor tank experiments of cross-classified design involving two or three densities of Dorosoma and two densities of the zooplanktivorous atherinid fish, Menidia beryllina. We attempted to discriminate between the direct and indirect effects of Dorosoma on phytoplankton by using Menidia to produce indirect effects on phytoplankton by suppressing Zooplankton. Experiments began in November, March, June, and September and lasted for 45–53 d. Dorosoma suppressed most Zooplankton in at least one experiment and enhanced algal standing crops in all four experiments, as indicated by increased algal chlorophyll fluorescence, turbidity, Coulter counts and microscopic algal counts, and decreased Secchi depths. Because in three out of four experiments Menidia suppressed Zooplankton biomass to a greater extent than Dorosoma without enhancing phytoplankton, we reject the hypothesis that the enhancement of phytoplankton by Dorosoma was an indirect effect of Zooplankton biomass suppression.
Selection for Adult Size in Female Coho Salmon (Oncorhynchus kisutch)
Authors: Holtby L B. , Healey M. C.
Published: October 2009

Several recent studies have presented evidence that large size confers a selective advantage to female Pacific salmon. Nevertheless, a wide range of female sizes is normally present in any spawning population. Two possible explanations exist for the observed range in female size. First, average female size might be determined by an optimizing process with variation around the optimum size due to individual differences in success at obtaining food. Second, various sizes of females might coexist as a mixed evolutionary stable strategy. Under the first explanation, females of sizes other than the optimum would display lower fitness whereas, under the second explanation, females of all sizes would be equally fit. We investigated factors affecting survival of eggs, fry, and smolts of coho salmon (Oncorhynchus kisutch) in Carnation Creek on Vancouver Island with a view to determining the relative fitness of different sized females. Egg-to-fry mortality was best explained by a model that included only the effects of stream bed scour and gravel quality. Including an effect of female size, expressed through depth of egg burying, worsened the model's predictive capability. We could find no evidence that the eggs of large females consistently survived better during incubation than those of small females. In fact, we observed three instances in which it appeared that the eggs of small females survived better. In Carnation Creek, large 1- and 2-yr-old smolts did not consistently survive better in the marine environment than small smolts. Thus, we were unable to demonstrate that the reproductive success of large females was consistently higher than that of small females, contrary to the hypothesis that female size is the result of an optimizing process. In Carnation Creek the observed range of female sizes probably represents an evolutionary stable strategy in which all sizes have equal fitness. We propose a model that predicts female size and variance in size based on the conflicting selective effects of gravel quality, scour, and competition for nest sites.
Effects of Flooding on Dissolved and Suspended Nutrients in Small Diked Marshes
Authors: Kadlec John A.
Published: October 2009

Flooding ten 5- to 7-ha diked marshes in the Delta Marsh, Manitoba, to about 1 m above natural marsh levels did not increase dissolved or suspended nutrient concentrations in the surface water. Dissolved forms of N and P increased in interstitial water, possibly as a direct or indirect effect of death of emergent macrophytes (e.g. cattail, Typha spp.) and associated changes such as wave action and detritus deposition. Concentrations of suspended N, P and C decreased in surface water as a result of flooding, both in absolute terms and relative to concurrent increases shown by natural marsh controls. Concentrations of major ions (Ca2+, Mg2+, Na+, K+[Formula: see text] and Cl−) did not change in response to flooding, but did vary in time and space. A predicted decrease in the concentrations of major ions in interstitial water due to seepage of dilute surface water into the sediment was not detected.
Estimating the Abundance of Stone-dwelling Organisms: A New Method
Authors: Wrona Frederick J. , Calow Peter , Ford Ian , Baird Donald J. , Maltby Lorraine
Published: October 2009

A system of stratified sampling has been developed which allows the estimation of population densities of organisms which adhere to, or are associated with, stones in both lentic and lotic habitats, using the stones themselves as the primary sampling units. Knowing the stone profile of the habitat (i.e. the mean count, relative frequency, or mean surface area of the stones occurring within a size class), and using the appropriate statistical equations, an estimate of the mean number of individuals occurring within a predefined stone size class can be obtained along with its associated error estimates. Densities of the organisms can be expressed in terms of either a standardized unit area of substratum, average stone size in the habitat, or unit area of stone surface. The statistical theory and computational equations for each sampling method are presented, together with worked examples of the application of the methods in the field. The new sampling protocols are superior to conventional quadrat techniques in population size estimation because (1) the derived density and error estimates account for sources of variation arising from both the heterogeneity of the habitat and the spatial dispersion of the organisms; (2) physical disturbance to the habitat during the sampling program is minimal, and (3) the procedures allow simultaneous quantitative measures of both the density and spatial dispersion of a population.
Comparison of Continuous and Episodic Exposure to Acidic, Aluminum-Contaminated Waters of Brook Trout (Salvelinus fontinalis)
Authors: Siddens Lisbeth K. , Seim Wayne K. , Curtis Lawrence R. , Chapman Gary A.
Published: October 2009

This study demonstrated that repetitive, intermittent exposures to aluminum (Al) under acidic conditions produced greater cumulative mortality and lower growth rates of brook trout (Salvelinus fontinalis) than would be extrapolated from continuous exposure experiments. During a 24-d study, exposures were at pH 4.4 or 4.9 with 0.2––1.2 mg Al∙L−1. Data were analyzed based on peak and 24-d mean Al concentrations of continuous and intermittent (2-d toxicant, 4-d ambient condition cycle) exposures. Survival was lower in groups exposed to at pH 4.9 than those at 4.4 when intermittently exposed but not when continuously exposed. Growth rates were less for fish continuously exposed at pH 4.4 compared with those at pH 4.9, while intermittent exposures to Al acidity alone did not affect growth. Fish intermittently exposed to Al at pH 4.4 grew faster than those at pH 4.9, indicating greater Al toxicity at the higher pH.
High Precision Microcomputer Based Measuring System for Ecological Research
Authors: Roff John C. , Hopcroft Russell R.
Published: October 2009

A semiautomated measuring system is described which allows precise multiple measurements on organisms of biological interest. It consists of a microscope with drawing tube positioned next to a digitizing tablet which is interfaced to a personal computer; a TV camera and monitor are optional additions. Light from an LED fitted cursor on the digitizing pad is focused through the drawing tube and combined with the microscope image. Measurement signals are sent to the computer when the cursor button is depressed. Data storage, calculation, and display can be performed on-line as data are entered. Maximum precision of repeated measurements is ±0.04%; in routine use an accuracy of < ±0.25% is achieved. An example of its precision compared with a conventional eyepiece micrometer is given. The system has been used for measurement of a diversity of aquatic particles including phytoplankton, Zooplankton, fecal pellets, and stream benthic invertebrates at magnifications from 10 to 1250 power.
Pullulan elaboration and differentiation of the resting forms in Aureobasidium pullulans
Authors: Simon L. , Bouchet B. , Caye-Vaugien C. , Gallant D. J.
Published: October 2009

To identify the cellular forms that are responsible for the synthesis of pullulan produced by Aureobasidium pullulans, we performed cytochemical and ultrastructural localizations of glucan in the cellular forms of this microorganism (blastospores and resting forms). Growth conditions, cell populations, and pullulan production were studied concurrently. Our results are consistent with a model in which the resting forms (swollen cells and chlamydospores) might be primarily involved in this extracellular polysaccharide elaboration. At the cellular level, pullulan production could be the result of three main stages: (i) cell wall thickening and extracellular polysaccharide synthesis by the swollen cell, (ii) fibrillar arrangement of this polysaccharide into pullulan along a capsular network around the chlamydospore, and (iii) subcellular hydrolysis separating the capsule from the periplasmic zone and consequently permitting the solubilization of pullulan in the culture medium. A melanization process in the outer layer of the cell wall and the capsule accompanies these patterns.Key words: Aureobasidium pullulans, capsule, cytochemistry, polysaccharide, pullulan, resting forms.
Diagnosis ofClostridium difficileassociated diarrhea: comparison of three rapid methods employing different markers for detection
Authors: Riederer Kathleen M. , Lawson Patrick , Held Marilyn S. , Petrylka Karen , Briski Laurence E. , Khatib Riad
Published: October 2009

Latex agglutination and the enzyme immunoassays Cytoclone (EIA-C) and VIDAS (EIA-V) were compared with a cytotoxicity assay for the diagnosis of Clostridium difficile associated diarrhea. Among patients with discrepant results, the cytotoxicity assay and clinical assessment were used to evaluate the performance of the latex agglutination and EIA tests. Clostridium difficile associated diarrhea was documented in 30/149 samples (20.1%) from 130 patients. All test results matched in 113 instances. Latex agglutination, EIA-C, and EIA-V yielded false positive results in 10, 4, and 7 samples and false negative results in 8, 9, and 14 samples, respectively. Latex agglutination demonstrated 87.8% efficiency compared with 91.3% for EIA-C and 85.7% for EIA-V and 3 min hands-on time compared with 4.5 min for EIA-V and 10 min for EIA-C. On the basis of these findings and given the fact that all rapid tests have their shortcomings, we believe that latex agglutination is the most practical method.Key words: Clostridium difficile, diarrhea, colitis.
The enhancement of plant growth by free-living bacteria
Authors: Glick Bernard R.
Published: October 2009

The ways in which plant growth promoting rhizobacteria facilitate the growth of plants are considered and discussed. Both indirect and direct mechanisms of plant growth promotion are dealt with. The possibility of improving plant growth promoting rhizobacteria by specific genetic manipulation is critically examined.Key words: plant growth promoting rhizobacteria, PGPR, bacterial fertilizer, soil bacteria.
Dispersal ofBacillus thuringiensisvar.kurstakiin an experimental cabbage field
Authors: Pedersen Jens Christian , Hansen Bjarne Munk , Damgaard Per Hyldebrink , Eilenberg Jørgen
Published: October 2009

The field population dynamics of Bacillus thuringiensis var. kurstaki DMU67R isolated from cabbage leaves was investigated. Two experimental cabbage plots were spray inoculated with a suspension of sporulated bacteria containing 6.5 × 107colony-forming units (cfu)/mL DMU67R or with a sterile medium control. To study transport between phyllosphere and soil, plastic covering was used during spraying to ensure that DMU67R was applied only on leaves (8.5 × 106cfu/g) or on soil (1.2 × 104cfu/g). Numbers of DMU67R declined five log units during the first 4 weeks after spraying of leaves; the initial half-life (1st week) was 16 h. In topsoil, however, a long-term persistency was demonstrated with a half-life exceeding 100 days. Dispersal by rain splash from topsoil to lower leaves of cabbage was demonstrated. After 1 year, analysis of the top 15 cm of soil showed that 77% of DMU67R remained in the 0- to 2-cm topsoil layer. When DMU67R was applied on leaves, larvae of Pieris brassicae were killed within 7 days after spraying. Germination of DMU67R was demonstrated in dead P. brassicae larvae but not in any leaf or soil sample. Pitfall sampling demonstrated dispersal of DMU67R by means of carabid beetles (up to 135 m) and other surface-active insects carrying 102–103 cfu/g wet mass.Key words: Bacillus thuringiensis, Pieris brassicae, cabbage, soil, dispersal, population dynamics.