bluuebunny/crossref_metadata_2025_split huggingface dataset:
Purification and properties of blackberry chlorotic ringspot, a new virus species in subgroup 1 of the genus Ilarvirus found naturally infecting blackberry in the UK
Authors: Jones A.T. , McGavin W.J. , Gepp V. , Zimmerman M.T. , Scott S.W. 
Published: August 2006

AbstractA mechanically transmissible virus was isolated from Bedford Giant blackberry plants showing chlorotic mottling and ringspot symptoms growing in Scotland. It infected several herbaceous test plants, many of them symptomlessly. This virus was also transmitted to several Rubus species and cultivars by graft inoculation with scions from the field‐infected Bedford Giant plant. Most grafted plants were infected symptomlessly, but Himalaya Giant blackberry and the hybrid berry Tayberry developed symptoms similar to those in the infected Bedford Giant plant. In the sap of infected Chenopodium quinoa, the virus lost infectivity when diluted 10−4 but not 10−3, after 6 h and 48 h when kept at 20°C and 4°C, respectively, but was infective for more than 8 days when kept at −15°C. Preparations of purified virus from infected C. quinoa or spinach sedimented as three major nucleoprotein components and consisted of quasi‐isometric particles that varied in size from 24 to 32 nm in diameter and that were not penetrated by negative stain. Such virus particle preparations contained a major polypeptide of ca 28 kDa and three single‐stranded RNA species of estimated size 3.2, 2.8 and 2.1 kb. The complete sequence of the largest RNA (RNA 1, 3478 nt) and the partial sequence of the other RNAs (1863 and 2102 nt long, respectively) were determined and compared with sequences in databases. These findings, together with the biological and biochemical properties of this virus, indicate that it should be regarded as a distinct species in subgroup 1 of the genus Ilarvirus even though it was serologically unrelated to existing members of this subgroup. The virus showed a very distant serological relationship with prune dwarf virus (PDV) but differed significantly from it in the amino acid sequence of its coat protein, experimental host range and symptomatology and was unrelated to PDV at the molecular level. The virus, tentatively named blackberry chlorotic ringspot virus, is therefore a newly described virus and the first ilarvirus found naturally infecting Rubus in the UK.
Plant extract contact toxicities to various developmental stages of Colorado potato beetles (Coleoptera: Chrysomelidae)
Authors: Gökçe A. , Whalon M.E. , Çam H. , Yanar Y. , Demirtaş İ. , Gören N. 
Published: August 2006

AbstractThe contact toxicities of methanol extracts from the nine plant species Hedera helix, Artemisia vulgaris, Xanthium strumarium, Humulus lupulus, Sambucus nigra, Chenopodium album, Salvia officinalis, Lolium temulentum and Verbascum songaricum were tested on the developmental stages of Colorado potato beetle (CPB) (Leptinotarsa decemlineata). About 2 mL of plant extract, 40% (w/w), was applied to the first instar to fourth instar larvae and adult beetles using a Potter spray tower. Most of the tested plant extracts caused relatively low mortality in all the beetle instars. Among the plant extracts, H. lupulus extract was the most toxic to all stages of the insect, except for the adult beetles. Larval mortality ranged from 40% in the fourth instars to 84% in the third instars. In a second series of experiments, dose–response bioassays using H. lupulus extract produced lethal concentration 50 (LC50) values ranging from 10%, 12%, 17% to 46% (w/w) active ingredient (plant material) for instars 1–4, respectively. This increasing mortality trend, however, did not extend to the adult stage where even the maximum dose of 40% plant material did not provide sufficient mortality to allow estimation of a LC50. These results demonstrated that the extract from H. lupulus has potential as an active ingredient in biological pesticides developed to manage larval instars of the CPB. The potential uses of this plant extract may be in conventional and organic pest management or as part of a mixture of plant extracts or conventional insecticides. Before extracts can be considered as biological control agents, their impact on natural enemies should be assessed.
A high-significance detection of non-Gaussianity in the WMAP 3-yr data using directional spherical wavelets
Authors: McEwen J. D. , Hobson M. P. , Lasenby A. N. , Mortlock D. J. 
Published: August 2006

Abstract
We repeat the directional spherical real Morlet wavelet analysis, used to detect non-Gaussianity in the Wilkinson Microwave Anisotropy Probe (WMAP) 1-yr data, on the WMAP 3-yr data. The non-Gaussian signal previously detected is indeed present in the 3-yr data, although the significance of the detection is reduced. Using our most conservative method for constructing significance measures, we find that the significance of the detection of non-Gaussianity drops from 98.3 ± 0.4 to 94.9 ± 0.7 per cent; the significance drops from 99.3 ± 0.3 to 97.2 ± 0.5 per cent using a method based on the χ2 statistic. The wavelet analysis allows us to localize most likely sources of non-Gaussianity on the sky. We detect very similar localized regions in the WMAP 1-yr and 3-yr data, although the regions extracted appear more pronounced in the 3-yr data. When all localized regions are excluded from the analysis, the 3-yr data are consistent with Gaussianity.
Isothermal shocks in Abell 2199 and 2A 0335+096?
Authors: Sanders J. S. , Fabian A. C. 
Published: August 2006

Abstract
We report on a partially circular X-ray surface brightness discontinuity found at about 55 kpc from the centre of Abell 2199 with Chandra X-ray Observatory observations. Unlike cold fronts found in other clusters, the feature shows no significant temperature change across it but has an apparent density jump. We therefore identify it as a weak isothermal shock associated with the central active galactic nucleus and the inflation of its radio bubbles, as found in the Perseus cluster. We examine a similar feature at 40 kpc radius found by Mazzotta et al. in 2A 0335+096, and conclude that it too may be an isothermal shock. The change in density if these are shocks implies a Mach number of ∼1.5. If the isothermal nature of these features is confirmed by deeper observations, the implication is that such shocks are common in clusters of galaxies, and are an important mechanism for the transport of energy from a central supermassive black hole into the cluster core.
A model for the infrared emission of FSC 10214+4724
Authors: Efstathiou Andreas 
Published: August 2006

Abstract
A model for the infrared emission of the high-redshift ultraluminous infrared galaxy FSC 10214+4724 is presented. The model assumes three components of emission: a dusty torus viewed edge-on, clouds that are associated with the narrow-line region and a highly obscured starburst. It is demonstrated that the presence of clouds in the narrow-line region, with a covering factor of 17 per cent, can explain why the mid-infrared spectrum of FSC 10214+4724 shows a silicate feature in emission despite the fact that its torus is viewed edge-on. It is also shown that the same model, but with the torus viewed face-on, predicts a spectrum with silicate emission features that is characteristic of the spectra of quasars recently observed with Spitzer.
PHYSIOLOGICAL AND BEHAVIORAL DEVELOPMENT IN DELPHINID CALVES: IMPLICATIONS FOR CALF SEPARATION AND MORTALITY DUE TO TUNA PURSE‐SEINE SETS
Authors: Noren Shawn R. , Edwards Elizabeth F. 
Published: August 2006

AbstractTuna purse‐seiners in the eastern tropical Pacific (ETP) capture yellowfin tuna by chasing and encircling herds of associated dolphins. This fishery has caused mortality in 14 dolphin species (20 stocks) and has led to significant depletions of at least three stocks. Although observed dolphin mortality is currently low, set frequency remains high and dolphin stocks are not recovering at expected rates. Mortality of nursing calves permanently separated from their mothers during fishery operations may be an important factor in the lack of population recovery, based on the recent discovery that calves do not accompany 75%–95% of lactating females killed in the purse‐seine nets. We assessed age‐specific potential for mother–calf separations and subsequent mortality of calves by reviewing and synthesizing published data on physiological and behavioral development in delphinids from birth through 3 yr postpartum. Results indicate that evasive behavior of mothers, coupled with the developmental state of calves, provides a plausible mechanism for set‐related mother–calf separations and subsequent mortality of calves. Potential for set‐related separation and subsequent mortality is highest for 0–12‐mo‐old dolphins and becomes progressively lower with age as immature dolphins approach adult stamina and attain independence.
Expression and Function of a Family of Transmembrane Kinases from the Protozoan Parasite
Entamoeba histolytica
Authors: Mehra Alka , Fredrick Jesse , Petri William A. , Bhattacharya Sudha , Bhattacharya Alok 
Published: August 2006

ABSTRACT

The signaling proteome of
Entamoeba histolytica
is made of transmembrane kinases (TMKs) that are rarely found in unicellular eukaryotes. There are 90 TMK genes reported for
E. histolytica
, and these have been grouped into nine distinct families based on motifs present on both extracellular and kinase domains. Of these, the B1 family was chosen for further analysis. Genomic sequencing revealed the presence of 28 members belonging to this family. Genes corresponding to the majority of these were truncated and not considered for further analysis. Only five members were full length and contained both extracellular and cytosolic kinase domains. BLAST analysis revealed the presence of homologs of these B1 TMKs in the nonpathogenic
Entamoeba dispar
. However, the ligand binding domains of the orthologous B1 TMKs of the two species showed considerable divergence, indicating the possibility of a correlation with the pathogenic potential of the organism. Only two of the five full-length copies (B1.I.1 and B1.I.2) were expressed in
E. histolytica
under the culture conditions used. Antisera generated against the extracellular domain of B1.I.1 stained the cell surface, particularly the areas of contact between the trophozoites. Staining was also seen in the frontal and posterior regions of the motile amoeba. An amoebic cell line expressing a truncated version of the B1.I.1 that lacked the kinase domain was generated. Inducible expression of the truncated TMK resulted in a decrease in cellular proliferation and an increase in sensitivity to serum starvation. Our data indicate that the B1.I class of TMKs is involved in parasite proliferation.
The
Bacteroides fragilis
Toxin Binds to a Specific Intestinal Epithelial Cell Receptor
Authors: Wu Shaoguang , Shin Jai , Zhang Guangming , Cohen Mitchell , Franco Augusto , Sears Cynthia L. 
Published: August 2006

ABSTRACT

The
Bacteroides fragilis
toxin (BFT) is the only known virulence factor of enterotoxigenic
B. fragilis
. BFT has previously been shown to act, at least in part, through cleavage of the intercellular adhesion protein E-cadherin. A specific cellular receptor for BFT has not been identified. The goal of this study was to determine if the initial interaction of BFT with intestinal epithelial cells was consistent with binding to a specific cellular receptor. Purified BFT was labeled with a fluorophore or iodide to assess specific cellular binding and the properties of BFT cellular binding. BFT binds specifically to intestinal epithelial cell lines in vitro in a polarized manner. However, specific binding occurs only at 37°C and requires BFT metalloprotease activity. The BFT receptor is predicted to be a membrane protein other than E-cadherin or a known protease-activated receptor (PAR1 to PAR4). BFT binding is resistant to acid washing, suggesting an irreversible interaction. Sugar or lipid residues do not appear to be involved in the mechanism of BFT cellular binding, but binding is sensitive to membrane cholesterol depletion. We conclude that intestinal epithelial cells in vitro possess a specific membrane BFT receptor that is distinct from E-cadherin. The data favor a model in which the metalloprotease domain of BFT processes its receptor protein, initiating cellular signal transduction that mediates the biological activity of BFT. However, activation of recognized protease-activated receptors does not mimic or block BFT biological activity or binding, suggesting that additional protease-activated receptors on intestinal epithelial cells remain to be identified.
The
Salmonella enterica
Serovar Typhi Type IVB Self-Association Pili Are Detached from the Bacterial Cell by the PilV Minor Pilus Proteins
Authors: Tam Connie K. P. , Morris Christina , Hackett Jim 
Published: August 2006

ABSTRACT

Salmonella enterica
serovar Typhi and some strains (Vi
+
) of serovar Dublin use type IVB pili to facilitate bacterial self-association, but only when the PilV proteins (potential minor pilus proteins) are not synthesized. Pilus-mediated self-association may be important in the pathogenesis of enteric fever. We have shown previously that the extent of DNA supercoiling controls the rate of Rci-catalyzed inversion of a DNA fragment which includes the C-terminal portions of the PilV proteins. This inversion therefore controls PilV synthesis as a high inversion rate prohibits transcription of
pilV
-encoding DNA. Here, we describe the manner in which PilV protein expression inhibits bacterial self-association and present data which suggest that incorporation of one or a few PilV protein molecules into a growing pilus, comprised of PilS subunits, causes the pilus to detach at the bacterial membrane. The bacteria are then unable to self-associate. We suggest that this phenomenon may be relevant to the pathogenesis of typhoid fever.
Infection of Human Endothelial Cells with Spotted Fever Group Rickettsiae Stimulates Cyclooxygenase 2 Expression and Release of Vasoactive Prostaglandins
Authors: Rydkina Elena , Sahni Abha , Baggs Raymond B. , Silverman David J. , Sahni Sanjeev K. 
Published: August 2006

ABSTRACTRickettsiae, a diverse group of obligately intracellular gram-negative bacteria, include etiologic agents of the spotted fever and typhus groups of diseases. Rocky Mountain spotted fever and boutonneuse fever, due toRickettsia rickettsiiandR. conorii, respectively, are characterized by widespread infection of the vascular endothelium, microvascular injury, and vasculitis. Cultured human endothelial cells (EC) are highly susceptible to infection and respond by altering the expression of adhesion molecules, regulatory cytokines, and the antioxidant enzyme heme oxygenase (HO). In the vasculature, HO regulates the cyclooxygenase (COX) enzymes, among which the inducible isozyme COX-2 facilitates the synthesis of prostaglandins (PGs). Using in vitro and ex vivo models of infection, we demonstrate here thatR. rickettsiiinfection of human EC causes robust induction of COX-2 mRNA and protein expression but has no apparent effect on the constitutive COX-1 isoform. Cells infected with viable rickettsiae consistently displayed significantly increased secretion of 6-keto-PGF1αand PGE2.R. rickettsii-induced COX-2 was sensitive to inhibitors of de novo transcription and the pyridinylimidazole-based compound SB 203580, suggesting that this transcriptional host cell response involves signaling through p38 mitogen-activated protein kinase. PG production by infected cells was abrogated by NS 398 (a selective COX-2 inhibitor) and indomethacin (a pan-COX inhibitor). Immunohistochemical staining of sections of infected umbilical cords and corresponding uninfected controls revealed comparatively more intense and abundant staining for COX-2 in infected endothelia. Induction of the endothelial COX-2 system and the resultant enhanced release of vasoactive PGs may contribute to the regulation of inflammatory responses and vascular permeability changes during spotted fever rickettsioses.
Yersinia pestis
YopJ Suppresses Tumor Necrosis Factor Alpha Induction and Contributes to Apoptosis of Immune Cells in the Lymph Node but Is Not Required for Virulence in a Rat Model of Bubonic Plague
Authors: Lemaître Nadine , Sebbane Florent , Long Daniel , Joseph Hinnebusch B. 
Published: August 2006

ABSTRACT

The virulence of the pathogenic
Yersinia
species depends on a plasmid-encoded type III secretion system that transfers six Yop effector proteins into host cells. One of these proteins, YopJ, has been shown to disrupt host cell signaling pathways involved in proinflammatory cytokine production and to induce macrophage apoptosis in vitro. YopJ-dependent apoptosis in mesenteric lymph nodes has also been demonstrated in a mouse model of
Yersinia pseudotuberculosis
infection. These results suggest that YopJ attenuates the host innate and adaptive immune response during infection, but the role of YopJ during bubonic plague has not been completely established. We evaluated the role of
Yersinia pestis
YopJ in a rat model of bubonic plague following intradermal infection with a fully virulent
Y. pestis
strain and an isogenic
yopJ
mutant. Deletion of
yopJ
resulted in a twofold decrease in the number of apoptotic immune cells in the bubo and a threefold increase in serum tumor necrosis factor alpha levels but did not result in decreased virulence, systemic spread, or colonization levels in the spleen and blood. Our results indicate that YopJ is not essential for bubonic plague pathogenesis, even after peripheral inoculation of low doses of
Y. pestis
. Instead, the effects of YopJ appear to overlap and augment the immunomodulatory effects of other
Y. pestis
virulence factors.
Lack of Eosinophil Peroxidase or Major Basic Protein Impairs Defense against Murine Filarial Infection
Authors: Specht Sabine , Saeftel Michael , Arndt Manuela , Endl Elmar , Dubben Bettina , Lee Nancy A. , Lee James J. , Hoerauf Achim 
Published: August 2006

ABSTRACTEosinophils are a hallmark of allergic diseases and helminth infection, yet direct evidence for killing of helminth parasites by their toxic granule products exists only in vitro. We investigated the in vivo roles of the eosinophil granule proteins eosinophil peroxidase (EPO) and major basic protein 1 (MBP) during infection with the rodent filariaLitomosoides sigmodontis. Mice deficient for either EPO or MBP on the 129/SvJ background developed significantly higher worm burdens than wild-type mice. Furthermore, the data indicate that EPO or MBP is involved in modulating the immune response leading to altered cytokine production during infection. Thus, in the absence of MBP, mice showed increased interleukin-10 (IL-10) production after stimulation of macrophages from the thoracic cavity where the worms reside. In addition to elevated IL-10 levels, EPO−/−mice displayed strongly increased amounts of the Th2 cytokine IL-5 by CD4 T cells as well as a significantly higher eosinophilia. Interestingly, a reduced ability to produce IL-4 in the knockout strains could even be seen in noninfected mice, arguing for different innate propensities to react with a Th2 response in the absence of either EPO or MBP. In conclusion, both of the eosinophil granule products MBP and EPO are part of the defense mechanism against filarial parasites. These data suggest a hitherto unknown interaction between eosinophil granule proteins, defense against filarial nematodes, and cytokine responses of macrophages and CD4 T cells.
Pulmonary Lymphatics Are Primary Sites of
Mycobacterium tuberculosis
Infection in Guinea Pigs Infected by Aerosol
Authors: Basaraba Randall J. , Smith Erin E. , Shanley Crystal A. , Orme Ian M. 
Published: August 2006

ABSTRACT

Mycobacterium tuberculosis
causes a lymphatic vasculitis in the lungs of guinea pigs infected by a low-dose aerosol. This observation suggests that in addition to being a direct conduit from the lungs to the regional lymph nodes, pulmonary lymphatics are themselves sites of infection and could be the site of latent infection.
Uropathogenic
Escherichia coli
Induces Extrinsic and Intrinsic Cascades To Initiate Urothelial Apoptosis
Authors: Klumpp David J. , Rycyk Matthew T. , Chen Michael C. , Thumbikat Praveen , Sengupta Shomit , Schaeffer Anthony J. 
Published: August 2006

ABSTRACT

A murine model of urinary tract infection identified urothelial apoptosis as a key event in the pathogenesis mediated by uropathogenic
Escherichia coli
(UPEC), yet the mechanism of this important host response is not well characterized. We employed a culture model of UPEC-urothelium interactions to examine the biochemical events associated with urothelial apoptosis induced by the UPEC strain NU14. NU14 induced DNA cleavage within 5 h that was inhibited by the broad caspase inhibitor ZVAD, and urothelial caspase 3 activity was induced within 3 h of exposure to type 1 piliated NU14 and was dependent upon interactions mediated by the type 1 pilus adhesin FimH. Flow cytometry experiments using chloromethyl-X-rosamine and Indo-1 revealed FimH-dependent mitochondrial membrane depolarization and elevated [Ca
2+
]
in
, respectively, indicating activation of the intrinsic apoptotic pathway. Consistent with this possibility, overexpression of Bcl
XL
inhibited NU14 activation of caspase 3. Immunoblotting, caspase inhibitors, and caspase activity assays implicated both caspase 2 and caspase 8 in apoptosis, suggesting the involvement of the intrinsic and extrinsic apoptotic cascades. To reconcile the apparent activation of both extrinsic and intrinsic pathways, we examined Bid-green fluorescent protein localization and observed translocation from the cytosol to mitochondria in response to either NU14 or purified FimH. These data suggest that FimH acts as a tethered toxin of UPEC that activates caspase-dependent urothelial apoptosis via direct induction of the extrinsic pathway and that the intrinsic pathway is activated indirectly as a result of coupling by caspase 8-mediated Bid cleavage.
Ligand-Signaled Upregulation of
Enterococcus faecalis ace
Transcription, a Mechanism for Modulating Host-
E. faecalis
Interaction
Authors: Nallapareddy Sreedhar R. , Murray Barbara E. 
Published: August 2006

ABSTRACT

Enterococcus faecalis
, the third most frequent cause of bacterial endocarditis, appears to be equipped with diverse surface-associated proteins showing structural-fold similarity to the immunoglobulin-fold family of staphylococcal adhesins. Among the putative
E. faecalis
surface proteins, the previously characterized adhesin Ace, which shows specific binding to collagen and laminin, was detectable in surface protein preparations only after growth at 46°C, mirroring the finding that adherence was observed in 46°C, but not 37°C, grown
E. faecalis
cultures. To elucidate the influence of different growth and host parameters on
ace
expression, we investigated
ace
expression using
E. faecalis
OG1RF grown in routine laboratory media (brain heart infusion) and found that
ace
mRNA levels were low in all growth phases. However, quantitative reverse transcription-PCR showed 18-fold-higher
ace
mRNA amounts in cells grown in the presence of collagen type IV compared to the controls. Similarly, a marked increase was observed when cells were either grown in the presence of collagen type I or serum but not in the presence of fibrinogen or bovine serum albumin. The production of Ace after growth in the presence of collagen type IV was demonstrated by immunofluorescence microscopy, mirroring the increased
ace
mRNA levels. Furthermore, increased Ace expression correlated with increased collagen and laminin adhesion. Collagen-induced Ace expression was also seen in three of three other
E. faecalis
strains of diverse origins tested, and thus it appears to be a common phenomenon. The observation of host matrix signal-induced adherence of
E. faecalis
may have important implications on our understanding of this opportunistic pathogen.