bluuebunny/crossref_metadata_2025 huggingface dataset:
Nosocomial Outbreak of Serious Canine Infectious Tracheobronchitis (Kennel Cough) Caused by Canine Herpesvirus Infection
Authors: Kawakami Kazuo , Ogawa Hiroyuki , Maeda Ken , Imai Ayako , Ohashi Emi , Matsunaga Satoru , Tohya Yukinobu , Ohshima Takahisa , Mochizuki Masami
Published: January 2010

Canine herpesvirus (CHV;Canid herpesvirus 1) is principally a perinatal pathogen of pregnant bitches and newborn pups and secondarily a respiratory tract pathogen of older pups and dogs. Infectious disease of the canine respiratory tract frequently occurs among dogs in groups, in which it is called “ infectious tracheobronchitis” (ITB). Mortality from ITB is generally negligible, and the clinical importance of CHV as an ITB pathogen is considered to be low. The present report describes a novel ITB outbreak accompanied by death among aged dogs in an animal medical center. Most inpatient dogs had received medications that could induce immunosuppression. CHV was the only pathogen identified, and several CHV isolates were recovered in cell culture. No other viral pathogens or significant bacterial pathogens were found. Molecular and serological analyses revealed that the causative CHV isolates were from a single source but that none was a peculiar strain when the strains were compared with previous CHV strains. The virus had presumably spread among the dogs predisposed to infection in the center. The present results serve as a warning to canine clinics that, under the specific set of circumstances described, such serious CHV outbreaks may be expected wherever canine ITB occurs.
Rapid Diagnosis of Azole-Resistant Aspergillosis by Direct PCR Using Tissue Specimens
Authors: van der Linden Jan W. M. , Snelders Eveline , Arends Jan P. , Daenen Simon M. , Melchers Willem J. G. , Verweij Paul E.
Published: January 2010

We report the use of PCR techniques on a formalin-fixed and paraffin-embedded tissue specimen for direct detection of one dominant azole resistance mechanism in a case of disseminated invasive aspergillosis. Rapid detection of mutations associated with azole resistance directly in tissue significantly reduces diagnostic delay.
Circulation of Mumps Virus Genotypes in Spain from 1996 to 2007
Authors: Echevarría J. E. , Castellanos A. , Sanz J. C. , Pérez C. , Palacios G. , Martínez de Aragón M. V. , Peña Rey I. , Mosquera M. , de Ory F. , Royuela E.
Published: January 2010

Although the WHO recommends the use of genotyping as a tool for epidemiological surveillance for mumps, limited data on mumps virus (MV) genotype circulation that may be used to trace the patterns of virus spread are available. We describe the first complete series of data from Spain. The small hydrophobic region was sequenced from 237 MV-positive samples from several regions of Spain collected between 1996 and 2007. Six different genotypes were identified: A, C, D (D1), G (G1, G2), H (H1, H2), and J. Genotype H1 was predominant during the epidemic that occurred from 1999 to 2003 but was replaced by genotype G1 as the dominant genotype in the epidemic that occurred from 2005 to 2007. The same genotype G1 strain caused concomitant outbreaks in different parts of the world (the United States, Canada, and the United Kingdom). The remaining genotypes (genotypes A, C, D, and J) appeared in sporadic cases or small limited outbreaks. This pattern of circulation seems to reflect continuous viral circulation at the national level, despite the high rates of vaccine coverage.
The NS5 Protein of the Virulent West Nile Virus NY99 Strain Is a Potent Antagonist of Type I Interferon-Mediated JAK-STAT Signaling
Authors: Laurent-Rolle Maudry , Boer Elena F. , Lubick Kirk J. , Wolfinbarger James B. , Carmody Aaron B. , Rockx Barry , Liu Wenjun , Ashour Joseph , Shupert W. Lesley , Holbrook Michael R. , Barrett Alan D. , Mason Peter W. , Bloom Marshall E. , García-Sastre Adolfo , Khromykh Alexander A. , Best Sonja M.
Published: January 2010

Flaviviruses transmitted by arthropods represent a tremendous disease burden for humans, causing millions of infections annually. All vector-borne flaviviruses studied to date suppress host innate responses to infection by inhibiting alpha/beta interferon (IFN-α/β)-mediated JAK-STAT signal transduction. The viral nonstructural protein NS5 of some flaviviruses functions as the major IFN antagonist, associated with inhibition of IFN-dependent STAT1 phosphorylation (pY-STAT1) or with STAT2 degradation. West Nile virus (WNV) infection prevents pY-STAT1 although a role for WNV NS5 in IFN antagonism has not been fully explored. Here, we report that NS5 from the virulent NY99 strain of WNV prevented pY-STAT1 accumulation, suppressed IFN-dependent gene expression, and rescued the growth of a highly IFN-sensitive virus (Newcastle disease virus) in the presence of IFN, suggesting that this protein can function as an efficient IFN antagonist. In contrast, NS5 from Kunjin virus (KUN), a naturally attenuated subtype of WNV, was a poor suppressor of pY-STAT1. Mutation of a single residue in KUN NS5 to the analogous residue in WNV-NY99 NS5 (S653F) rendered KUN NS5 an efficient inhibitor of pY-STAT1. Incorporation of this mutation into recombinant KUN resulted in 30-fold greater inhibition of JAK-STAT signaling than with the wild-type virus and enhanced KUN replication in the presence of IFN. Thus, a naturally occurring mutation is associated with the function of NS5 in IFN antagonism and may influence virulence of WNV field isolates.
Inhibition of Herpes Simplex Virus Type 1 Replication by Adeno-Associated Virus Rep Proteins Depends on Their Combined DNA-Binding and ATPase/Helicase Activities
Authors: Glauser Daniel L. , Seyffert Michael , Strasser Regina , Franchini Marco , Laimbacher Andrea S. , Dresch Christiane , de Oliveira Anna Paula , Vogel Rebecca , Büning Hildegard , Salvetti Anna , Ackermann Mathias , Fraefel Cornel
Published: January 2010

Adeno-associated virus (AAV) has previously been shown to inhibit the replication of its helper virus herpes simplex virus type 1 (HSV-1), and the inhibitory activity has been attributed to the expression of the AAV Rep proteins. In the present study, we assessed the Rep activities required for inhibition of HSV-1 replication using a panel of wild-type and mutant Rep proteins lacking defined domains and activities. We found that the inhibition of HSV-1 replication required Rep DNA-binding and ATPase/helicase activities but not endonuclease activity. The Rep activities required for inhibition of HSV-1 replication precisely coincided with the activities that were responsible for induction of cellular DNA damage and apoptosis, suggesting that these three processes are closely linked. Notably, the presence of Rep induced the hyperphosphorylation of a DNA damage marker, replication protein A (RPA), which has been reported not to be normally hyperphosphorylated during HSV-1 infection and to be sequestered away from HSV-1 replication compartments during infection. Finally, we demonstrate that the execution of apoptosis is not required for inhibition of HSV-1 replication and that the hyperphosphorylation of RPA
per se
is not inhibitory for HSV-1 replication, suggesting that these two processes are not directly responsible for the inhibition of HSV-1 replication by Rep.
Pharmacological Manipulation of the Akt Signaling Pathway Regulates Myxoma Virus Replication and Tropism in Human Cancer Cells
Authors: Werden Steven J. , McFadden Grant
Published: January 2010

Viruses have evolved an assortment of mechanisms for regulating the Akt signaling pathway to establish a cellular environment more favorable for viral replication. Myxoma virus (MYXV) is a rabbit-specific poxvirus that encodes many immunomodulatory factors, including an ankyrin repeat-containing host range protein termed M-T5 that functions to regulate tropism of MYXV for rabbit lymphocytes and certain human cancer cells. MYXV permissiveness in these human cancer cells is dependent upon the direct interaction between M-T5 and Akt, which has been shown to induce the kinase activity of Akt. In this study, an array of compounds that selectively manipulate Akt signaling was screened and we show that only a subset of Akt inhibitors significantly decreased the ability of MYXV to replicate in previously permissive human cancer cells. Furthermore, reduced viral replication efficiency was correlated with lower levels of phosphorylated Akt. In contrast, the PP2A-specific phosphatase inhibitor okadaic acid promoted increased Akt kinase activation and rescued MYXV replication in human cancer cells that did not previously support viral replication. Finally, phosphorylation of Akt at residue Thr308 was shown to dictate the physical interaction between Akt and M-T5, which then leads to phosphorylation of Ser473 and permits productive MYXV replication in these human cancer cells. The results of this study further characterize the mechanism by which M-T5 exploits the Akt signaling cascade and affirms this interaction as a major tropism determinant that regulates the replication efficiency of MYXV in human cancer cells.
Macrophage Receptors for Influenza A Virus: Role of the Macrophage Galactose-Type Lectin and Mannose Receptor in Viral Entry
Authors: Upham Jacqueline P. , Pickett Danielle , Irimura Tatsuro , Anders E. Margot , Reading Patrick C.
Published: January 2010

Although sialic acid has long been recognized as the primary receptor determinant for attachment of influenza virus to host cells, the specific receptor molecules that mediate viral entry are not known for any cell type. For the infection of murine macrophages by influenza virus, our earlier study indicated involvement of a C-type lectin, the macrophage mannose receptor (MMR), in this process. Here, we have used direct binding techniques to confirm and characterize the interaction of influenza virus with the MMR and to seek additional macrophage surface molecules that may have potential as receptors for viral entry. We identified the macrophage galactose-type lectin (MGL) as a second macrophage membrane C-type lectin that binds influenza virus and is known to be endocytic. Binding of influenza virus to MMR and MGL occurred independently of sialic acid through Ca
2+
-dependent recognition of viral glycans by the carbohydrate recognition domains of the two lectins; influenza virus also bound to the sialic acid on the MMR. Multivalent ligands of the MMR and MGL inhibited influenza virus infection of macrophages in a manner that correlated with expression of these receptors on different macrophage populations. Influenza virus strain A/PR/8/34, which is poorly glycosylated and infects macrophages poorly, was not recognized by the C-type lectin activity of either the MMR or the MGL. We conclude that lectin-mediated interactions of influenza virus with the MMR or the MGL are required for the endocytic uptake of the virus into macrophages, and these lectins can thus be considered secondary or coreceptors with sialic acid for infection of this cell type.
Glycosylation of PrP
C
Determines Timing of Neuroinvasion and Targeting in the Brain following Transmissible Spongiform Encephalopathy Infection by a Peripheral Route
Authors: Cancellotti Enrico , Bradford Barry M. , Tuzi Nadia L. , Hickey Raymond D. , Brown Debbie , Brown Karen L. , Barron Rona M. , Kisielewski Dorothy , Piccardo Pedro , Manson Jean C.
Published: January 2010

Transmissible spongiform encephalopathy (TSE) infectivity naturally spreads from site of entry in the periphery to the central nervous system where pathological lesions are formed. Several routes and cells within the host have been identified as important for facilitating the infectious process. Expression of the glycoprotein cellular PrP (PrP
C
) is considered a key factor for replication of infectivity in the central nervous system (CNS) and its transport to the brain, and it has been suggested that the infectious agent propagates from cell to cell via a domino-like effect. However, precisely how this is achieved and what involvement the different glycoforms of PrP have in these processes remain to be determined. To address this issue, we have used our unique models of gene-targeted transgenic mice expressing different glycosylated forms of PrP. Two TSE strains were inoculated intraperitoneally into these mice to assess the contribution of diglycosylated, monoglycosylated, and unglycosylated PrP in spreading of infectivity to the brain. This study demonstrates that glycosylation of host PrP has a profound effect in determining the outcome of disease. Lack of diglycosylated PrP slowed or prevented disease onset after peripheral challenge, suggesting an important role for fully glycosylated PrP in either the replication of the infectious agent in the periphery or its transport to the CNS. Moreover, mice expressing unglycosylated PrP did not develop clinical disease, and mice expressing monoglycosylated PrP showed strikingly different neuropathologic features compared to those expressing diglycosylated PrP. This demonstrates that targeting in the brain following peripheral inoculation is profoundly influenced by the glycosylation status of host PrP.
Biphasic Recruitment of Transcriptional Repressors to the Murine Cytomegalovirus Major Immediate-Early Promoter during the Course of Infection
In Vivo
Authors: Liu Xue-feng , Yan Shixian , Abecassis Michael , Hummel Mary
Published: January 2010

Our previous studies showed that establishment of murine cytomegalovirus (MCMV) latency
in vivo
is associated with repression of immediate-early gene expression, deacetylation of histones bound to the major immediate-early promoter (MIEP), changes in patterns of methylation of histones, and recruitment of cellular repressors of transcription to the MIEP. Here, we have quantitatively analyzed the kinetics of changes in viral RNA expression, DNA copy number, and recruitment of repressors and activators of transcription to viral promoters during the course of infection. Our results show that changes in viral gene expression correlate with changes in recruitment of RNA polymerase and acetylated histones to viral promoters. Binding of the transcriptional repressors histone deacetylase type 2 (HDAC2), HDAC3, YY1, CBF-1/RBP-Jk, Daxx, and CIR to the MIEP and HDACs to other promoters showed a biphasic pattern: some binding was detectable prior to activation of viral gene expression, then decreased with the onset of transcription and increased again as repression of viral gene expression occurred. Potential binding sites for CBF-1/RBP-Jk and YY1 in the MIEP and for YY1 in the
M100
promoter (M100P) were identified by
in silico
analysis. While recruitment of HDACs was not promoter specific, binding of CBF-1/RBP-Jk and YY1 was restricted to promoters with their cognate sites. Our results suggest that sequences within viral promoters may contribute to establishment of latency through recruitment of transcriptional repressors to these genes. The observation that repressors are bound to the MIEP and other promoters immediately upon infection suggests that latency may be established in some cells very early in infection.
Efficient Budding of the Tacaribe Virus Matrix Protein Z Requires the Nucleoprotein
Authors: Groseth Allison , Wolff Svenja , Strecker Thomas , Hoenen Thomas , Becker Stephan
Published: January 2010

The Z protein has been shown for several arenaviruses to serve as the viral matrix protein. As such, Z provides the principal force for the budding of virus particles and is capable of forming virus-like particles (VLPs) when expressed alone. For most arenaviruses, this activity has been shown to be linked to the presence of proline-rich late-domain motifs in the C terminus; however, for the New World arenavirus Tacaribe virus (TCRV), no such motif exists within Z. It was recently demonstrated that while TCRV Z is still capable of functioning as a matrix protein to induce the formation of VLPs, neither its ASAP motif, which replaces a canonical PT/SAP motif in related viruses, nor its YxxL motif is involved in budding, leading to the suggestion that TCRV uses a novel budding mechanism. Here we show that in comparison to its closest relative, Junin virus (JUNV), TCRV Z buds only weakly when expressed in isolation. While this budding activity is independent of the ASAP or YxxL motif, it is significantly enhanced by coexpression with the nucleoprotein (NP), an effect not seen with JUNV Z. Interestingly, both the ASAP and YxxL motifs of Z appear to be critical for the recruitment of NP into VLPs, as well as for the enhancement of TCRV Z-mediated budding. While it is known that TCRV budding remains dependent on the endosomal sorting complex required for transport, our findings provide further evidence that TCRV uses a budding mechanism distinct from that of other known arenaviruses and suggest an essential role for NP in this process.
Comparison of the Biological and Biochemical Activities of Several Members of the Alphaherpesvirus ICP0 Family of Proteins
Authors: Everett Roger D. , Boutell Chris , McNair Carol , Grant Louise , Orr Anne
Published: January 2010

Immediate-early protein ICP0 of herpes simplex virus type 1 (HSV-1) is an E3 ubiquitin ligase of the RING finger class that is required for efficient lytic infection and reactivation from latency. Other alphaherpesviruses also express ICP0-related RING finger proteins, but these have limited homology outside the core RING domain. Existing evidence indicates that ICP0 family members have similar properties, but there has been no systematic comparison of the biochemical activities and biological functions of these proteins. Here, we describe an inducible cell line system that allows expression of the ICP0-related proteins of bovine herpes virus type 1 (BHV-1), equine herpesvirus type 1 (EHV-1), pseudorabies virus (PRV), and varicella-zoster virus (VZV) and their subsequent functional analysis. We report that the RING domains of all the proteins have E3 ubiquitin ligase activityin vitro. The BHV-1, EHV-1, and PRV proteins complement ICP0-null mutant HSV-1 plaque formation and induce derepression of quiescent HSV-1 genomes to levels similar to those achieved by ICP0 itself. VICP0, the ICP0 expressed by VZV, was found to be extremely unstable, which limited its analysis in this system. We compared the abilities of the ICP0-related proteins to disrupt ND10, to induce degradation of PML and Sp100, to affect key components of the interferon signaling pathway, and to interfere with induction of interferon-stimulated genes. We found that the property that correlated most closely with their biological activities was the ability to preclude the recruitment of cellular ND10 proteins to sites closely associated with incoming HSV-1 genomes and early replication compartments.
Isolation of an Infectious Endogenous Retrovirus in a Proportion of Live Attenuated Vaccines for Pets
Authors: Miyazawa Takayuki , Yoshikawa Rokusuke , Golder Matthew , Okada Masaya , Stewart Hazel , Palmarini Massimo
Published: January 2010

The genomes of all animal species are colonized by endogenous retroviruses (ERVs). Although most ERVs have accumulated defects that render them incapable of replication, fully infectious ERVs have been identified in various mammals. In this study, we isolated a feline infectious ERV (RD-114) in a proportion of live attenuated vaccines for pets. Isolation of RD-114 was made in two independent laboratories using different detection strategies and using vaccines for both cats and dogs commercially available in Japan or the United Kingdom. This study shows that the methods currently employed to screen veterinary vaccines for retroviruses should be reevaluated.
Temporal changes in species composition of mixedwood stands in northwest New Brunswick: 1946–2008
Authors: Amos-Binks Luke J. , MacLean David A. , Wilson Jeremy S. , Wagner Robert G.
Published: January 2010

Patterns of softwood (SW) – hardwood (HW) change from 1946 to 2006 in 32 unharvested mixedwood (MW) stands in northern New Brunswick were analyzed using aerial photographs (1946, 1966, 1982, and 2006), sampled, and related to disturbance and stand conditions. Five stand development patterns were identified based on 1946 SW content (70%–80%, termed SW versus 30%–60%, termed MW) and change in SW content from 1946 to 2006 (SW-stable, SW-declining, MW-fluctuating, MW-stable, or MW-declining). Species composition was surprisingly changeable over this 60-year period, with change in SW content varying from +18% to –62%. High canopy cover reduction from 1946 to 1966 resulted from balsam fir ( Abies balsamea (L.) Mill.) mortality due to old age and a 1950s spruce budworm ( Choristoneura fumiferana Clem.) outbreak plus birch ( Betula sp.) dieback. SW-stable stands that maintained SW composition from 1946 to 2006 (+7%) had more red spruce ( Picea rubens Sarg.) than all other classes in which SW declined by 15%–47%. SW-declining stands were located on southerly aspects (189°) and had higher mean elevations (423 m) than other classes. Results suggest that balsam fir – tolerant HW MW stands may be naturally transitional due to disturbance, species, and stand conditions, which has significant implications for forest management designed to maintain static proportions of MW and SW stands.
Predicting the impact of hemlock woolly adelgid on carbon dynamics of eastern United States forests
Authors: Albani Marco , Moorcroft Paul R. , Ellison Aaron M. , Orwig David A. , Foster David R.
Published: January 2010

The hemlock woolly adelgid (HWA; Adelges tsugae Annand) is an introduced insect pest that threatens to decimate eastern hemlock ( Tsuga canadensis (L.) Carriere) populations. In this study, we used the ecosystem demography model in conjunction with a stochastic model of HWA spread to predict the impact of HWA infestation on the current and future forest composition, structure, and carbon (C) dynamics in the eastern United States. The spread model predicted that on average the hemlock stands south and east of the Great Lakes would be infested by 2015, southern Michigan would be reached by 2020, and northeastern Minnesota by 2030. For the period 2000–2040, the ecosystem demography model predicted a mean reduction of 0.011 Pg C·year–1 (Pg C = 1015 g C), an 8% decrease, in the uptake of carbon from eastern United States forests as a result of HWA-caused mortality, followed by an increased uptake of 0.015 Pg C·year–1 (a 12% increase) in the period 2040–2100, as the area recovers from the loss of hemlock. Overall, we conclude that while locally severe, HWA infestation is unlikely to have a significant impact on the regional patterns of carbon fluxes, given that eastern hemlock represents a limited fraction of the standing biomass of eastern forests and that it has relatively low productivity compared with the tree species that are likely to replace it.
The influence of overstorey Populus on epiphytic lichens in subboreal spruce forests of British Columbia
Authors: Campbell Jocelyn , Bradfield Gary E. , Prescott Cindy E. , Fredeen Arthur L.
Published: January 2010

The composition and abundance of lichen communities on conifer saplings beneath five overstorey tree species were compared at three subboreal forest site types in east-central British Columbia. Site-level differences in lichen communities were attributed to different levels of moisture and light limitations in the understorey. At sites with adequate moisture and light, cyanolichens were uniformly abundant and species rich on conifer saplings beneath different understorey species. However, at sites with moisture or light limitations, cyanolichens were more abundant and species rich on conifer saplings beneath overstorey Populus than on saplings beneath other overstorey tree species. Cyanolichen communities also showed greater species richness on conifer saplings beneath the Populus canopy than on the trunk of Populus itself. Differences in calcium, phosphorus, molybdenum, and manganese availability in throughfall precipitation failed to explain much of the variation in lichen community structure. These results suggest that Populus can facilitate cyanolichens under sub optimal moisture or light conditions by providing some, as yet unknown, factor that is critical to their establishment and growth.
Root growth response to water and nutrients in the New Jersey Pinelands
Authors: Gleeson Scott K. , Good Ralph E.
Published: January 2010

Resource limitation theory regarding water versus nutrient limitation predicts on the one hand that, because of uptake trade-offs, increases in water will increase limitation by nutrients; on the other hand, because of supply interactions, increases in water will lead to correlated increases in nutrient availability. Using root ingrowth into resource-enriched soil cores as an assay of resource limitation, we report the effect of variable water supply on two experiments in the New Jersey Pinelands. In the first experiment in an upland oak–pine habitat, root ingrowth was highest in nitrogen-enriched cores in a wet year and highest in water-enriched cores in a dry year. In the second experiment in four vegetation types that differ in water table depth, roots grew more into nitrogen-enriched cores in all habitats, but nitrogen cores did not stimulate more ingrowth in wet (pitch pine lowland, hardwood swamp) versus dry habitats (pine–oak upland, oak–pine upland). Experiment 1 is consistent with the expectation that increasing water will increase relative limitation by mineral nutrients, but experiment 2 is not. Experiment 2 is consistent with an alternate hypothesis that long-term plant–soil feedback will result in higher nutrient acquisition in sites of higher water availability.
Cinétique de l'infection de plants d'Heveabrasiliensis (Willd. ex Adr. de Juss) Mull. Arg. par Rigidoporuslignosus (Kl.) Imazeki
Authors: Nicole M. , Nandris D. , Geiger J.-P.
Published: January 2010

Using an artificial inoculation technique, a kinetic infection study of Heveabrasiliensis (Willd. ex Adr. de Juss) Mull. Arg. by Rigidoporuslignosus (Kl.) Imazeki has shown the existence of a three-stage infection process: (i) a particularly fast contamination stage. After 15 days of exposure, all plants showed rhizomorphs to be present on taproots; (ii) the spread of epiphytic mycelium all over taproots is associated with numerous punctual penetrations allowing tissue invasion and infection. Beginning at the apex, a rot develops and progresses upward; in less than 3 months, it affects nearly 40% of the invaded plants' taproot. In response to this, the host develops reaction mechanisms which become evident at the cellular level and on the entire plant; and (iii) at this time, a state of equilibrium is reached between the host and the parasite which is shown through a stagnant disease progress. The efficiency of the various host reactions observed in the plants is discussed. [Journal translation]
On seasonal variation in the nutrient content of needle litter from Scots pine
Authors: Raunemaa T. , Hautojärvi A. , Samela J. , Erkinjuntti R. , Hari P. , Kellomäki S.
Published: January 2010

The multielemental PIXE method was applied to analysis of Pinussylvestris L. needle litter to determine 14 micro- and macro-nutrients simultaneously. Clear seasonal variation in the elemental composition was experimentally revealed. There were three groupings of the elements. Calcium and manganese content was shown to increase rapidly, while the concentration of several other elements decreased during senescence. Deviations observed in the systematic yearly cycling are proposed to be coupled with nutritive imbalance. A simulation model for the nutrient transport based on gross biological arguments has been developed and tested with the material. The model, with only four parameters for each element, can be widely used for dynamic investigations of nutrient flows. Care in sampling is necessary.
Douglas-fir height growth affected by western spruce budworm
Authors: Sickle G. A. Van , Alfaro R.I. , Thomson A.J.
Published: January 2010

Detailed dissections of Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) trees repeatedly defoliated by the western spruce budworm (Choristoneuraoccidentalis (Freeman)) in two areas of British Columbia indicated that budworm severely affected height growth. Dissected trees lost an average 7.3 internodes in each infestation, of which 4.2 were destroyed or failed to grow during the budworm feeding and recovery periods, and 3.1 were existing internodes lost to dieback. An average of one internode of subnormal size, produced during the recovery period, was also present. Total height was reduced by 32% (11.4 m) and 19% (5.9 m) in areas that sustained four and two infestations respectively. Budworm infestations lead to an underestimation of the site index for Douglas-fir in the affected areas.
Survey and mass trapping of ambrosia beetles (Coleoptera: Scolytidae) in timber processing areas on Vancouver Island
Authors: Lindgren B. S. , Borden J. H.
Published: January 2010

The spatial distribution and population estimates of overwintering Trypodendronlineatum (Olivier) were determined by sampling beetles in the duff at four dryland log sorts. The temporal and spatial distributions of flying T. lineatum, Gnathotrichussulcatus (LeConte), and G. retusus (LeConte) over 3 years were determined by catches by pheromone-baited traps in three dryland sorts. At one dryland sort the distribution data from survey trapping and overwintering sampling were used to establish optimal trap placement for the subsequent year's trapping. At this dryland sort the trapping effort was expanded from a survey into a mass trapping program, using a barrier strategy. The total catches of all three species in 1979, 1980, and 1981 were 120 000, 690 000, and 2 800 000, respectively. Approximately 66 and 79% of the captured beetles in 1980 and 1981, respectively, were T. lineatum. When compared with high and low population estimates of overwintering T. lineatum the catches of this species represented 1–3, 12–21, and 44–77% of the total overwintering population for the respective years. For each year, the following winter's population remained constant relative to previous years. A mass trapping program, utilizing synthetic pheromones, multiple funnel traps, and sticky vane traps, was recommended in conjunction with improved log inventory management.
Expérimentation sur la compétition interspécifique par élimination sélective d'espèces forestières
Authors: Bellefleur P. , Pétillon Y.
Published: January 2010

We conducted an experimental study of competition for water, heat, and space between woody species and herbaceous species by selective exclusion of a few species in a sugar maple stand. We found large differences in diameter and height increment for all three species under investigation: sugar maple, yellow birch, and beech. Large differences were also found in soil temperatures to a depth of 30 cm which were correlated with cover and growth increment. We concluded that there is indeed a severe competition between woody and herbaceous species for both heat and space.
THE EQUATION OF STATE OF QUASI-PARTICLE MODEL OF QUARK–GLUON PLASMA AT FINITE CHEMICAL POTENTIAL
Authors: ZHAO A-MENG , CAO JING , LUO LIU-JUN , SUN WEI-MIN , ZONG HONG-SHI
Published: January 2010

In this letter we propose a new method of calculating the equation of state (EOS) of quasi-particle model of quark–gluon plasma at finite chemical potential. In the quasi-particle model the quark propagator has the form of a free quark propagator with a temperature and density dependent effective mass. From this quark propagator the EOS at finite chemical potential is calculated using the model-independent formula proposed in Refs. 16 and 17. A comparison between our EOS and the cold, perturbative EOS of QCD proposed in Ref. 23 is made.
BOUNCING BRANEWORLD WITH BORN–INFELD AND GAUSS–BONNET
Authors: MUKHERJI SUDIPTA , PAL SUPRATIK
Published: January 2010

We show the existence of some bouncing cosmological solutions in the braneworld scenario. More specifically, we consider a dynamical three-brane in the background of Born–Infeld and electrically charged Gauss–Bonnet black hole. We find that, in certain range of parameter space, the brane universe, at least classically, never shrinks to a zero size, resulting in a singularity-free cosmology within the classical domain.
COMPUTING WORD LENGTH IN ALTERNATE PRESENTATIONS OF THOMPSON'S GROUP F
Authors: HORAK MATTHEW , STEIN MELANIE , TABACK JENNIFER
Published: January 2010

We introduce a new method for computing the word length of an element of Thompson's group F with respect to a "consecutive" generating set of the form Xn = {x0,x1, …,xn}, which is a subset of the standard infinite generating set for F. We use this method to show that (F, Xn) is not almost convex, and has pockets of increasing, though bounded, depth dependent on n.
BUCHSTEINER LOOPS
Authors: CSÖRGŐ PIROSKA , DRÁPAL ALEŠ , KINYON MICHAEL K.
Published: January 2010

Buchsteiner loops are those which satisfy the identity x \ (xy · z) = (y · zx) / x. We show that a Buchsteiner loop modulo its nucleus is an abelian group of exponent four, and construct an example where the factor achieves this exponent.
A BAYESIAN NETWORKS APPROACH TO MODELING FINANCIAL RISKS OF E-LOGISTICS INVESTMENTS
Authors: SHEN CHIEN-WEN
Published: January 2010

To evaluate whether the investments of e-logistics systems may increase financial risks, models of Bayesian networks are constructed in this study with the mechanism of structural learning and parameter learning. Empirical findings from the transport and logistics sectors suggest that the e-logistics investments generally do not increase the financial risks of companies except the implementation of computer aided picking systems and radio frequency identification. Meanwhile, only the investment of enterprise resource planning can reduce the financial risks and enhance the profitability at the same time. Generally speaking, most advanced e-logistics investments do not yield financial advantages for the transport and logistics companies from the perspective of Bayesian inference. Empirical study based on the proposed models also demonstrates the practicability of Bayesian models.
Inhibition of SERCA pumps induces desynchronized RyR activation in overloaded internal Ca2+ stores in smooth muscle cells
Authors: Gómez-Viquez Norma Leticia , Guerrero-Serna Guadalupe , Arvizu Fernando , García Ubaldo , Guerrero-Hernández Agustín
Published: January 2010

We have previously shown that rapid inhibition of sarcoplasmic reticulum (SR) ATPase (SERCA pumps) decreases the amplitude and rate of rise (synchronization) of caffeine induced-Ca2+ release without producing a reduction of free luminal SR Ca2+ level in smooth muscle cells (Gómez-Viquez L, Guerrero-Serna G, García U, Guerrero-Hernández A. Biophys J 85: 370–380, 2003). Our aim was to investigate the role of luminal SR Ca2+ content in the communication between ryanodine receptors (RyRs) and SERCA pumps. To this end, we studied the effect of SERCA pump inhibition on RyR-mediated Ca2+ release in smooth muscle cells with overloaded SR Ca2+ stores. Under this condition, the amplitude of RyR-mediated Ca2+ release was not affected but the rate of rise was still decreased. In addition, the caffeine-induced Ca2+-dependent K+ outward currents revealed individual events, suggesting that SERCA pump inhibition reduces the coordinated activation of RyRs. Collectively, our results indicate that SERCA pumps facilitate the activation of RyRs by a mechanism that does not involve the regulation of SR Ca2+ content. Importantly, SERCA pumps and RyRs colocalize in smooth muscle cells, suggesting a possible local communication between these two proteins.
Dexamethasone stimulates store-operated calcium entry and protein degradation in cultured L6 myotubes through a phospholipase A2-dependent mechanism
Authors: Itagaki Kiyoshi , Menconi Michael , Antoniu Bozena , Zhang Qin , Gonnella Patricia , Soybel David , Hauser Carl , Hasselgren Per-Olof
Published: January 2010

Muscle wasting in various catabolic conditions is at least in part regulated by glucocorticoids. Increased calcium levels have been reported in atrophying muscle. Mechanisms regulating calcium homeostasis in muscle wasting, in particular the role of glucocorticoids, are poorly understood. Here we tested the hypothesis that glucocorticoids increase intracellular calcium concentrations in skeletal muscle and stimulate store-operated calcium entry (SOCE) and that these effects of glucocorticoids may at least in part be responsible for glucocorticoid-induced protein degradation. Treatment of cultured myotubes with dexamethasone, a frequently used in vitro model of muscle wasting, resulted in increased intracellular calcium concentrations determined by fura-2 AM fluorescence measurements. When SOCE was measured by using calcium “add-back” to muscle cells after depletion of intracellular calcium stores, results showed that SOCE was increased 15–25% by dexamethasone and that this response to dexamethasone was inhibited by the store-operated calcium channel blocker BTP2. Dexamethasone treatment stimulated the activity of calcium-independent phospholipase A2 (iPLA2), and dexamethasone-induced increase in SOCE was reduced by the iPLA2 inhibitor bromoenol lactone (BEL). In additional experiments, treatment of myotubes with the store-operated calcium channel inhibitor gadolinium ion or BEL reduced dexamethasone-induced increase in protein degradation. Taken together, the results suggest that glucocorticoids increase calcium concentrations in myocytes and stimulate iPLA2-dependent SOCE and that glucocorticoid-induced muscle protein degradation may at least in part be regulated by increased iPLA2 activity, SOCE, and cellular calcium levels.
Volume-sensitive outwardly rectifying chloride channel in white adipocytes from normal and diabetic mice
Authors: Inoue Hana , Takahashi Nobuyuki , Okada Yasunobu , Konishi Masato
Published: January 2010

The volume-sensitive outwardly rectifying (VSOR) chloride channel is ubiquitously expressed and involved in cell volume regulation after osmotic swelling, called regulatory volume decrease (RVD), in various cell types. In adipocytes, the expression of the VSOR channel has not been explored to date. Here, by employing the whole-cell patch-clamp technique, we examined whether or not the VSOR channel is expressed in white adipocytes freshly isolated from epididymal fat pads of normal (C57BL/6 or KK) and diabetic (KKAy) mice. Whole cell voltage-clamp recordings revealed that Cl− currents were gradually activated upon cell swelling induced by application of a hypotonic solution, both in normal and diabetic adipocytes. Although both the mean cell size (or cell capacitance) and the current magnitude in KKAy adipocytes were larger than those in C57BL/6 cells, the current density was significantly lower in KKAy adipocytes (23.32 ± 1.94 pA in C57BL/6 adipocytes vs. 13.04 ± 2.41 pA in KKAy adipocytes at +100 mV). Similarly, the current density in diabetic KKAy adipocytes was lower than that in adipocytes from KK mice (a parental strain of KKAy mice), which do not present diabetes until an older age. The current was inhibited by Cl− channel blockers, 5-nitro-2-(3-phenylpropylamino)benzoic acid (NPPB) and glibenclamide, or hypertonic solution, and showed outward rectification and inactivation kinetics at large positive potentials. These electrophysiological and pharmacological properties are consistent with those of the VSOR channel in other cell types. Moreover, adipocytes showed RVD, which was inhibited by NPPB. In KKAy adipocytes, RVD was significantly slower (τ; 8.42 min in C57BL/6 adipocytes vs. 11.97 min in KKAy adipocytes) and incomplete during the recording period (25 min). It is concluded that the VSOR channel is functionally expressed and involved in volume regulation in white adipocytes. RVD is largely impaired in adipocytes from diabetic mice, presumably as a consequence of the lower density of the functional VSOR channel in the plasma membrane.
Mechanisms of proximal tubule sodium transport regulation that link extracellular fluid volume and blood pressure
Authors: McDonough Alicia A.
Published: January 2010

One-hundred years ago, Starling articulated the interdependence of renal control of circulating blood volume and effective cardiac performance. During the past 25 years, the molecular mechanisms responsible for the interdependence of blood pressure (BP), extracellular fluid volume (ECFV), the renin-angiotensin system (RAS), and sympathetic nervous system (SNS) have begun to be revealed. These variables all converge on regulation of renal proximal tubule (PT) sodium transport. The PT reabsorbs two-thirds of the filtered Na+and volume at baseline. This fraction is decreased when BP or perfusion pressure is increased, during a high-salt diet (elevated ECFV), and during inhibition of the production of ANG II; conversely, this fraction is increased by ANG II, SNS activation, and a low-salt diet. These variables all regulate the distribution of the Na+/H+exchanger isoform 3 (NHE3) and the Na+-phosphate cotransporter (NaPi2), along the apical microvilli of the PT. Natriuretic stimuli provoke the dynamic redistribution of these transporters along with associated regulators, molecular motors, and cytoskeleton-associated proteins to the base of the microvilli. The lipid raft-associated NHE3 remains at the base, and the nonraft-associated NaPi2 is endocytosed, culminating in decreased Na+transport and increased PT flow rate. Antinatriuretic stimuli return the same transporters and regulators to the body of the microvilli associated with an increase in transport activity and decrease in PT flow rate. In summary, ECFV and BP homeostasis are, at least in part, maintained by continuous and acute redistribution of transporter complexes up and down the PT microvilli, which affect regulation of PT sodium reabsorption in response to fluctuations in ECFV, BP, SNS, and RAS.
Lesions of area postrema and subfornical organ alter exendin-4-induced brain activation without preventing the hypophagic effect of the GLP-1 receptor agonist
Authors: Baraboi Elena-Dana , Smith Pauline , Ferguson Alastair V. , Richard Denis
Published: January 2010

The mechanism and route whereby glucagon-like peptide 1 (GLP-1) receptor agonists, such as GLP-1 and exendin-4 (Ex-4), access the central nervous system (CNS) to exert their metabolic effects have yet to be clarified. The primary objective of the present study was to investigate the potential role of two circumventricular organs (CVOs), the area postrema (AP) and the subfornical organ (SFO), in mediating the metabolic and CNS-stimulating effects of Ex-4. We demonstrated that electrolytic ablation of the AP, SFO, or AP + SFO does not acutely prevent the anorectic effects of Ex-4. AP + SFO lesion chronically decreased food intake and body weight and also modulated the effect of Ex-4 on the neuronal activation of brain structures involved in the hypothalamic-pituitary-adrenal axis and glucose metabolism. The results of the study also showed that CVO lesions blunted Ex-4-induced expression of c- fos mRNA (a widely used neuronal activity marker) in 1) limbic structures (bed nucleus of the stria terminalis and central amygdala), 2) hypothalamus (paraventricular hypothalamic nucleus, supraoptic nucleus, and arcuate nucleus), and 3) hindbrain (lateral and lateral-external parabrachial nucleus, medial nucleus of the solitary tract, and ventrolateral medulla). In conclusion, although the present results do not support a role for the CVOs in the anorectic effect induced by a single injection of Ex-4, they suggest that the CVOs play important roles in mediating the actions of Ex-4 in the activation of CNS structures involved in homeostatic control.
Tubuloglomerular feedback is decreased in COX-1 knockout mice after chronic angiotensin II infusion
Authors: Araujo Magali , Welch William J.
Published: January 2010

Prostaglandins (PGs), produced by two isoforms of cyclooxygenase (COX), COX-1 and COX-2, are important modulators of renal hemodynamics. COX-1 and COX-2 are expressed in the kidney often at distinct sites. Thromboxane (TxA2), PGE2, and prostacyclin (PGI2) are the major PGs in the renal cortex of mice. Acute infusion of the vasoconstrictor ANG II increases COX-2-dependent PGE2 and PGI2. COX-2 is primarily expressed in the macula densa (MD), where several PG synthases are also expressed. We previously showed that MD COX-2 products modulate tubuloglomerular feedback (TGF) in the rat. Genetic deletion of COX-1 enhances COX-2 production of PGs, decreases renal and urinary PGs, and attenuates ANG II-induced hypertension. The present study tested the effects of chronic ANG II infusion on TGF in COX-1 knockout (KO) mice. Basal TGF was similar in COX-1 KO and wild-type (WT) mice. Chronic ANG II infusion increased TGF in WT mice (WT: 9.3 ± 0.7 vs. WT + ANG II: 12.2 ± 1.6 mmHg, P < 0.02). However, chronic ANG II decreased TGF in COX-1 KO mice (KO: 11.4 ± 1.1 vs. KO + ANG II: 8.3 ± 0.6 mmHg, P < 0.01). Pretreatment with the COX-2 inhibitor SC-58,236 in COX-1 KO mice prevented the ANG II-associated reduction in TGF (11.4 ± 1.0 vs. 11.5 ± 0.28 mmHg, not significant). Excretion of 6-keto-PGF2α, the metabolite of PGI2, was increased by ANG II infusion, whereas excretion of TxB2, the stable metabolite of TxA2, was not changed. ANG II infusion increased mean arterial pressure similarly in both WT and KO mice (WT: 93 ± 2 vs. KO: 92 ± 3 mmHg), but not in KO mice pretreated with SC-58,236 (85 ± 2 mmHg). This study shows that COX-1-generated PGs partially mediate ANG II increases in TGF and that COX-2 PGs offset that effect.
Response Latency to Lingual Taste Stimulation Distinguishes Neuron Types Within the Geniculate Ganglion
Authors: Breza Joseph M. , Nikonov Alexandre A. , Contreras Robert J.
Published: January 2010

The purpose of this study was to investigate the role of response latency in discrimination of chemical stimuli by geniculate ganglion neurons in the rat. Accordingly, we recorded single-cell 5-s responses from geniculate ganglion neurons ( n = 47) simultaneously with stimulus-evoked summated potentials (electrogustogram; EGG) from the anterior tongue to signal when the stimulus contacted the lingual epithelium. Artificial saliva served as the rinse solution and solvent for all stimuli [(0.5 M sucrose, 0.03−0.5 M NaCl, 0.01 M citric acid, and 0.02 M quinine hydrochloride (QHCl)], 0.1 M KCl as well as for 0.1 M NaCl +1 μM benzamil. Cluster analysis separated neurons into four groups (sucrose specialists, NaCl specialists, NaCl/QHCl generalists and acid generalists). Artificial saliva elevated spontaneous firing rate and response frequency of all neurons. As a rule, geniculate ganglion neurons responded with the highest frequency and shortest latency to their best stimulus with acid generalist the only exception. For specialist neurons and NaCl/QHCl generalists, the average response latency to the best stimulus was two to four times shorter than the latency to secondary stimuli. For NaCl-specialist neurons, response frequency increased and response latency decreased systematically with increasing NaCl concentration; benzamil significantly decreased NaCl response frequency and increased response latency. Acid-generalist neurons had the highest spontaneous firing rate and were the only group that responded consistently to citric acid and KCl. For many acid generalists, a citric-acid-evoked inhibition preceded robust excitation. We conclude that response latency may be an informative coding signal for peripheral chemosensory neurons.