bluuebunny/crossref_metadata_2025_split huggingface dataset:
The compatibility of the fungicide azoxystrobin with Pochonia chlamydosporia, a biological control agent for potato cyst nematodes (Globodera spp.)
Authors: Tobin J.D. , Haydock P.P.J. , Hare M.C. , Woods S.R. , Crump D.H. 
Published: February 2008

AbstractThe biological control potential of Pochonia chlamydosporia against root‐knot (Meloidogyne spp.) and cyst‐forming (Heterodera and Globodera spp.) nematodes is widely appreciated. In spite of this, little has been undertaken to determine the compatibility of this fungus with modern fungicides. A series of experiments were undertaken to investigate the effect of azoxystrobin on P. chlamydosporia. Initial Petri dish experiments found a significant reduction in the growth of P. chlamydosporia. EC50 values were calculated at 7 and 14 mg L−1, respectively, for hyphal growth and chlamydospore germination. A microcosm experiment based on counts of the colony‐forming units of the re‐isolated fungus showed a reduction in EC50 values for azoxystrobin in soil after 12, 20 and 40 days incubation (1.25, 1.00 and 3.00 mg kg−1 soil, respectively). There was evidence the fungus recovered over time in response to azoxystrobin application. This was also demonstrated in a glasshouse experiment where EC50 values of 1.32 and 4.4 mg kg−1 soil were obtained for 35 and 49 days after planting (DAP), respectively.
Evaluation of a Dialysis Sampler’s Integrity in a Cold Climate
Authors: Iwakun O. , Biggar K. , Armstrong J. , Donahue R. , Sego D. 
Published: February 2008

AbstractThe use of a diffusion sampler made from regenerated cellulose dialysis membrane was investigated in this study to resolve issues from previous studies on the integrity of the sampler when deployed in the field. The dialysis samplers were deployed in monitoring wells at two upstream oil‐ and gas‐contaminated sites. The average ambient temperature in the monitoring wells was 4 ± 1°C over the 6 month duration of the test. Burst pressure and tensile strength tests were used to determine the integrity of the samplers at two field sites over time. The test results showed no adverse impacts on the samplers’ integrity after 6 months. Therefore, diffusion samplers from regenerated cellulose dialysis membrane show promising results when used for long‐term monitoring associated with natural attenuation assessment under the conditions tested.
In situ Mixing of Organic Matter Decreases Hydraulic Conductivity of Denitrification Walls in Sand Aquifers
Authors: Barkle Gregory F. , Schipper Louis A. , Burgess Craig P. , Painter Brett D.M. 
Published: February 2008

AbstractIn a previous study, a denitrification wall was constructed in a sand aquifer using sawdust as the carbon substrate. Ground water bypassed around this sawdust wall due to reduced hydraulic conductivity. We investigated potential reasons for this by testing two new walls and conducting laboratory studies. The first wall was constructed by mixing aquifer material in situ without substrate addition to investigate the effects of the construction technique (mixed wall). A second, biochip wall, was constructed using coarse wood chips to determine the effect of size of the particles in the amendment on hydraulic conductivity. The aquifer hydraulic conductivity was 35.4 m/d, while in the mixed wall it was 2.8 m/d and in the biochip wall 3.4 m/d. This indicated that the mixing of the aquifer sands below the water table allowed the particles to re‐sort themselves into a matrix with a significantly lower hydraulic conductivity than the process that originally formed the aquifer. The addition of a coarser substrate in the biochip wall significantly increased total porosity and decreased bulk density, but hydraulic conductivity remained low compared to the aquifer. Laboratory cores of aquifer sand mixed under dry and wet conditions mimicked the reduction in hydraulic conductivity observed in the field within the mixed wall. The addition of sawdust to the laboratory cores resulted in a significantly higher hydraulic conductivity when mixed dry compared to cores mixed wet. This reduction in the hydraulic conductivity of the sand/sawdust cores mixed under saturated conditions repeated what occurred in the field in the original sawdust wall. This indicated that laboratory investigations can be a useful tool to highlight potential reductions in field hydraulic conductivities that may occur when differing materials are mixed under field conditions.
Left Ventricular Diastolic Function in Nigerian Patients with Essential Hypertension: A Retrospective Study to Compare Angiotensin Converting Enzyme Inhibitors, Calcium Channel Blockade or Their Combination
Authors: Ajayi Olufemi E. , Akintomide Anthony O. , Adigun Adegboyega Q. , Ajayi Adesuyi A. L. 
Published: February 2008

ABSTRACTBackground.  Hypertension in blacks imposes a greater left ventricular hypertrophy, and accelerated heart failure onset. We evaluated and compared the echocardiographically determined systolic and left ventricular diastolic functional indices in Nigerian hypertensive patients, associated with the chronic use of ACE inhibitors, Calcium channel blockers (CCB) or their combinations.Methods.  Ejection fraction ‐EF, intraventricular relaxation time (IVRT), E/A peak velocity ratio, E wave deceleration time] as well as the left ventricular mass index (LVMI) was undertaken among 41 Nigerian patients with essential hypertension only, on treatment for 4–6 months prior. The 41 patients (aged 59 ± 10 years, 40% females) were divided into three groups; those receiving (i) ACE inhibitors; or (ii) CCB or (iii) combination of ACEI and CCB. All the three groups had a background of diuretic treatment for optimal blood pressure control.Results.  There were no statistically significant differences in the mean LVMI or sitting blood pressure between treatment groups. E/A ratio for ACEI treatment was 1.06 ± 0.44, CCB 0.74 ± 0.19, and for ACEI + CCB 0.87 ± 0.26 (F = 3.29, P = 0.048 anova). The 95% confidence interval for the E/A ratio on ACEI was 0.8 to 1.33. The A wave duration time integral (AVVTi) were all abnormally large, but showed a significant between treatment group difference (P = 0.037, anova). The values were 21.9 ± 4.7 for ACEI, 25.3 ± 6.3 for CCB, and least at 20.1 ± 3.6 cm for the ACE + CCB combination. Similarly, the IVRT was lowest and <100 ms with ACEI + CCB being 93 ± 18 ms, ACEI 115 ± 23 ms, and CCB being 117 ± 22 ms (F = 4.92, P = 0.01, anova). The 95% CI for IVRT on ACEI + CCB was 82 to 104 ms. There were no between treatment group differences in systolic contractility, (fractional shortening or EF).Conclusions.  The results indicate that use of an antihypertensive drug regime inclusive of an ACE inhibitor (±CCB) may be associated with greater salutary effect on indices of diastolic function, (E/A > 1, lower AVVTi, IVRT < 100 ms) even in the presence of an equivalent effect on systolic function and blood pressure.
Three Thioesterases Are Involved in the Biosynthesis of Phosphinothricin Tripeptide in
Streptomyces viridochromogenes
Tü494
Authors: Eys S. , Schwartz D. , Wohlleben W. , Schinko E. 
Published: February 2008

ABSTRACT

Phosphinothricin tripeptide (PTT) is a peptide antibiotic produced by
Streptomyces viridochromogenes
Tü494, and it is synthesized by nonribosomal peptide synthetases. The PTT biosynthetic gene cluster contains three peptide synthetase genes:
phsA
,
phsB
, and
phsC
. Each of these peptide synthetases comprises only one module. In neither PhsB nor PhsC is a typical C-terminal thioesterase domain present. In contrast, a single thioesterase GXSXG motif has been identified in the N terminus of the first peptide synthetase, PhsA. In addition, two external thioesterase genes,
theA
and
theB
, are located within the PTT biosynthetic gene cluster. To analyze the thioesterase function as well as the assembly of the peptide synthetases within PTT biosynthesis, several mutants were generated and analyzed. A
phsA
deletion mutant (MphsA) was complemented with two different
phsA
constructs that were carrying mutations in the thioesterase motif. In one construct, the thioesterase motif comprising 45 amino acids of
phsA
were deleted. In the second construct, the conserved serine residue of the GXSXG motif was replaced by an alanine. In both cases, the complementation of MphsA did not restore PTT biosynthesis, revealing that the thioesterase motif in the N terminus of PhsA is required for PTT production. In contrast, TheA and TheB might have editing functions, as an interruption of the
theA
and
theB
genes led to reduced PTT production, whereas an overexpression of both genes in the wild type enhanced the PTT yield. The presence of an active single thioesterase motif in the N terminus of PhsA points to a novel mechanism of product release.
Plasmid-Mediated
qepA
Gene among
Escherichia coli
Clinical Isolates from Japan
Authors: Yamane Kunikazu , Wachino Jun-ichi , Suzuki Satowa , Arakawa Yoshichika 
Published: February 2008

ABSTRACT

Seven hundred fifty-one
Escherichia coli
clinical isolates collected from 140 Japanese hospitals between 2002 and 2006 were screened for the
qepA
and
qnr
genes. Two
E. coli
isolates (0.3%) harbored
qepA
, but no
qnr
was identified. The results suggested a low prevalence of
E. coli
harboring
qepA
or
qnr
in Japan.
Activity of Daptomycin against
Listeria monocytogenes
Isolates from Cerebrospinal Fluid
Authors: Spanjaard Lodewijk , Vandenbroucke-Grauls Christina M. J. E. 
Published: February 2008

ABSTRACT

We tested the activity of daptomycin against 76
Listeria monocytogenes
isolates from cerebrospinal fluid by broth dilution and Etest methods. For the broth dilution method, the MIC range was 1.0 to 8.0 and the MIC at which 90% of the isolates tested were inhibited (MIC
90
) was 4.0 mg/liter. For the Etest method, the MIC range was 1.0 to 4.0 and the MIC
90
was 4.0 mg/liter. Presently, daptomycin cannot be recommended for the treatment of
L. monocytogenes
meningitis.
Predictive Values of the Human Immunodeficiency Virus Phenotype and Genotype and of Amprenavir and Lopinavir Inhibitory Quotients in Heavily Pretreated Patients on a Ritonavir-Boosted Dual-Protease-Inhibitor Regimen
Authors: Barrail-Tran Aurélie , Morand-Joubert Laurence , Poizat Gwendoline , Raguin Gilles , Le Tiec Clotilde , Clavel François , Dam Elisabeth , Chêne Geneviève , Girard Pierre-Marie , Taburet Anne-Marie 
Published: February 2008

ABSTRACTThe inhibitory quotient (IQ) of human immunodeficiency virus (HIV) protease inhibitors (PIs), which is the ratio of drug concentration to viral susceptibility, is considered to be predictive of the virological response. We used several approaches to calculate the IQs of amprenavir and lopinavir in a subset of heavily pretreated patients participating in the French National Agency for AIDS Research (ANRS) 104 trial and then compared their potentials for predicting changes in the plasma HIV RNA level. Thirty-seven patients were randomly assigned to receive either amprenavir (600 mg twice a day [BID]) or lopinavir (400 mg BID) plus ritonavir (100 or 200 mg BID) for 2 weeks before combining the two PIs. The 90% inhibitory concentration (IC90) was measured using a recombinant assay without or with additional human serum (IC90+serum). Total and unbound PI concentrations in plasma were measured. Univariate linear regression was used to estimate the relation between the change in viral load and the IC90or IQ values. The amprenavir phenotypic IQ values were very similar when measured with the standard and protein binding-adjusted IC90s. No relationship was found between the viral load decline and the lopinavir IQ. During combination therapy, the amprenavir and lopinavir genotypic IQ values were predictive of the viral response at week 6 (P= 0.03). The number of protease mutations (<5 or ≥5) was related to the virological response throughout the study. These findings suggest that the combined genotypic IQ and the number of protease mutations are the best predictors of virological response. High amprenavir and lopinavir concentrations in these patients might explain why plasma concentrations and the phenotypic IQ have poor predictive value.
The Hepatitis C Virus Replicon Presents a Higher Barrier to Resistance to Nucleoside Analogs than to Nonnucleoside Polymerase or Protease Inhibitors
Authors: McCown Matthew F. , Rajyaguru Sonal , Le Pogam Sophie , Ali Samir , Jiang Wen-Rong , Kang Hyunsoon , Symons Julian , Cammack Nick , Najera Isabel 
Published: February 2008

ABSTRACT
Specific inhibitors of hepatitis C virus (HCV) replication that target the NS3/4A protease (e.g., VX-950) or the NS5B polymerase (e.g., R1479/R1626, PSI-6130/R7128, NM107/NM283, and HCV-796) have advanced into clinical development. Treatment of patients with VX-950 or HCV-796 rapidly selected for drug-resistant variants after a 14-day monotherapy treatment period. However, no viral resistance was identified after monotherapy with R1626 (prodrug of R1479) or NM283 (prodrug of NM107) after 14 days of monotherapy. Based upon the rapid selection of resistance to the protease and nonnucleoside inhibitors during clinical trials and the lack of selection of resistance to the nucleoside inhibitors, we used the replicon system to determine whether nucleoside inhibitors demonstrate a higher genetic barrier to resistance than protease and nonnucleoside inhibitors. Treatment of replicon cells with nucleoside inhibitors at 10 and 15 times the 50% effective concentration resulted in clearance of the replicon, while treatment with a nonnucleoside or protease inhibitor selected resistant colonies. In combination, the presence of a nucleoside inhibitor reduced the frequency of colonies resistant to the other classes of inhibitors. These results indicate that the HCV replicon presents a higher barrier to the selection of resistance to nucleoside inhibitors than to nonnucleoside or protease inhibitors. Furthermore, the combination of a nonnucleoside or protease inhibitor with a nucleoside polymerase inhibitor could have a clear clinical benefit through the delay of resistance emergence.
A Peptide with a ProGln C Terminus in the Human Saliva Peptidome Exerts Bactericidal Activity against
Propionibacterium acnes
Authors: Huang Chun-Ming , Torpey Justin W. , Liu Yu-Tseung , Chen Yun-Ru , Williams Katherine E. , Komives Elizabeth A. , Gallo Richard L. 
Published: February 2008

ABSTRACT

Nine proline-rich peptides ending with a proline-glutamine C terminus in a salivary peptidome were sequenced by matrix-assisted laser desorption ionization time of flight time of flight tandem mass spectrometry. A GPPPQGGRPQ peptide binds gram-positive
Propionibacterium acnes
and considerably inhibits bacterial growth. The peptide exhibiting innate immunity may be applied for treatment of various
P. acnes
-associated human diseases.
Genetic Susceptibility to Chronic Hepatitis Is Inherited Codominantly in
Helicobacter hepaticus
-Infected AB6F1 and B6AF1 Hybrid Male Mice, and Progression to Hepatocellular Carcinoma Is Linked to Hepatic Expression of Lipogenic Genes and Immune Function-Associated Networks
Authors: García Alexis , Ihrig Melanie M. , Fry Rebecca C. , Feng Yan , Xu Sandy , Boutin Samuel R. , Rogers Arlin B. , Muthupalani Suresh , Samson Leona D. , Fox James G. 
Published: February 2008

ABSTRACT

Helicobacter hepaticus
causes hepatitis in susceptible strains of mice. Previous studies indicated that A/JCr mice are susceptible and C57BL/6NCr mice are resistant to
H. hepaticus
-induced hepatitis. We used F1 hybrid mice derived from A/J and C57BL/6 matings to investigate their phenotype and determine their hepatic gene expression profile in response to
H. hepaticus
infection. F1 hybrid mice, as well as parental A/J and C57BL/6 mice, were divided equally into control and
H. hepaticus
-infected groups and euthanized at 18 months postinoculation. Hepatic lesions were evaluated histologically and the differential hepatic gene expression in F1 mice was determined by microarray-based global gene expression profiling analysis.
H. hepaticus
-infected parental strains including A/J and C57BL/6 mice, as well as F1 mice, developed significant hepatitis. Overall, hepatocellular carcinomas or dysplastic liver lesions were observed in 69% of
H. hepaticus
-infected F1 male mice and
H. hepaticus
was isolated from hepatic tissues of all F1 mice with liver tumors. Liver tumors, characterized by hepatic steatosis, developed in livers with high hepatitis scores. To identify gene expression specific to
H. hepaticus
-induced hepatitis and progression to hepatocellular carcinoma in F1 mice, a method using comparative group transcriptome analysis was utilized. The canonical pathway most significantly enriched was immunological disease. Fatty acid synthase and steaoryl-coenzyme A desaturase, the two rate-limiting enzymes in lipogenesis, were upregulated in neoplastic relative to dysplastic livers. This study suggests a synergistic interaction between hepatic steatosis and infectious hepatitis leading to hepatocellular carcinoma. The use of AB6F1 and B6AF1 mice, as well as genetically engineered mice, on a C57BL/6 background will allow studies investigating the role of chronic microbial hepatitis and steatohepatitis in the pathogenesis of liver cancer.
Human Dendritic Cell-Specific Intercellular Adhesion Molecule-Grabbing Nonintegrin (CD209) Is a Receptor forYersinia pestisThat Promotes Phagocytosis by Dendritic Cells
Authors: Zhang Pei , Skurnik Mikael , Zhang Shu-Sheng , Schwartz Olivier , Kalyanasundaram Ramaswamy , Bulgheresi Silvia , He Johnny J. , Klena John D. , Hinnebusch B. Joseph , Chen Tie 
Published: February 2008

ABSTRACTYersinia pestisis the etiologic agent of bubonic and pneumonic plagues. It is speculated thatY. pestishijacks antigen-presenting cells (APCs), such as dendritic cells (DCs) and alveolar macrophages, in order to be delivered to lymph nodes. However, how APCs initially capture the bacterium remains uncharacterized. It is well known that HIV-1 uses human DC-specific intercellular adhesion molecule-grabbing nonintegrin (DC-SIGN) (CD209) receptor, expressed by APCs, to be captured and delivered to target cell, such as CD4+lymphocytes. Several gram-negative bacteria utilize their core lipopolysaccharides (LPS) as ligands to interact with the human DC-SIGN. Therefore, it is possible thatY. pestis, whose core LPS is naturally exposed, might exploit DC-SIGN to invade APCs. We demonstrate in this study thatY. pestisdirectly interacts with DC-SIGN and invades both DCs and alveolar macrophages. In contrast, when engineered to cover the core LPS,Y. pestisloses its ability to invade DCs, alveolar macrophages, and DC-SIGN-expressing transfectants. The interaction betweenY. pestisand human DCs can be reduced by a combination treatment with anti-CD209 and anti-CD207 antibodies. This study shows that human DC-SIGN is a receptor forY. pestisthat promotes phagocytosis by DCs in vitro.
Intracellular Neutralization of Shiga Toxin 2 by an A Subunit-Specific Human Monoclonal Antibody
Authors: Krautz-Peterson Greice , Chapman-Bonofiglio Susan , Boisvert Karen , Feng Hanping , Herman Ira M. , Tzipori Saul , Sheoran Abhineet S. 
Published: February 2008

ABSTRACT

Infection of children with Shiga toxin (Stx)-producing
Escherichia coli
(STEC) is the leading cause of hemolytic-uremic syndrome (HUS). Stx2, one of two toxins liberated by the bacteria, is directly linked with HUS. We have previously shown that Stx2-specific human monoclonal antibodies (HuMAbs) protect mice and piglets from fatal systemic complications of Stx2. The present study investigates the mechanisms by which our most efficacious A- and B-subunit-specific HuMAbs neutralize the cytotoxic effects of Stx2 in vitro. Whereas the B-subunit-specific HuMAb 5H8 blocked binding of Stx2 to its receptor on the cell surface, the A-subunit-specific HuMAb 5C12 did not interfere with the toxin-receptor binding. Further investigations revealed that 5C12 did not block endocytosis of Stx2 by HeLa cells as both Stx2 and 5C12 colocalized with early endosomes. However, 5C12 blocked the retrograde transport of the toxin into the Golgi and the endoplasmic reticulum, preventing the toxin from entering the cytosol where the toxin exerts its cytotoxic effect. The endocytosed 5C12/Stx2 complexes appear to be rapidly transported to the plasma membrane and/or to the slow recycling perinuclear compartments, followed by their slow recycling to the plasma membrane, and release into the extracellular environment.
Protective Heterologous Immunity against Fatal Ehrlichiosis and Lack of Protection following Homologous Challenge
Authors: Thirumalapura Nagaraja R. , Stevenson Heather L. , Walker David H. , Ismail Nahed 
Published: February 2008

ABSTRACTThe roles of antibodies and memory T cells in protection against virulentEhrlichiahave not been completely investigated. In this study, we addressed these issues by using murine models of mild and fatal ehrlichiosis caused by related monocytotropicEhrlichiastrains. Mice were primed with eitherEhrlichia murisor closely related virulent ehrlichiae transmitted byIxodes ovatus(IOE) ticks given intraperitoneally or intradermally. All groups were reinfected intraperitoneally, 30 days later, with a lethal high dose of IOE. Priming withE. muris, but not IOE, induced strong CD4+and CD8+memory type 1 T-cell responses,Ehrlichia-specific immunoglobulin G (IgG) antibodies, and persistent infection. Compared to IOE-primed mice, subsequent lethal IOE challenge ofE. muris-primed mice, resulted in (i) 100% protection against lethal infection, (ii) strongEhrlichia-specific secondary gamma interferon (IFN-γ)-producing effector/effector memory CD4+and CD8+T-cell responses, (iii) enhanced secondary anti-ehrlichial antibody response, (iv) accelerated bacterial clearance, and (v) the formation of granulomas in the liver and lung.E. muris-primed mice challenged with IOE had lower levels of serum interleukin-1α (IL-1α), IL-6, and IL-10 compared to unprimed mice challenged with IOE. Interestingly, the fatal secondary response in IOE-primed mice correlated with (i) decline in theEhrlichia-specific CD4+and CD8+type 1 responses, (ii) marked hepatic apoptosis and necrosis, and (iii) substantial bacterial clearance, suggesting that fatal secondary response is due to immune-mediated tissue damage. In conclusion, protection against fatal ehrlichial infection correlates with strong expansion of IFN-γ-producing CD4+and CD8+effector memory type 1 T cells, which appear to be maintained in the presence of IgG antibodies and persistent infection.
The EtpA Exoprotein of Enterotoxigenic
Escherichia coli
Promotes Intestinal Colonization and Is a Protective Antigen in an Experimental Model of Murine Infection
Authors: Roy Koushik , Hamilton David , Allen Kenneth P. , Randolph Mildred P. , Fleckenstein James M. 
Published: February 2008

ABSTRACT

The enterotoxigenic
Escherichia coli
(ETEC) strains are major causes of morbidity and mortality due to diarrheal illness in developing countries. At present, there is no broadly protective vaccine for this diverse group of pathogens. The EtpA protein, identified in ETEC H10407 in a recent search for candidate immunogens, is a large glycosylated exoprotein secreted via two-partner secretion (TPS). Similar to structurally related molecules, EtpA functions in vitro as an adhesin. The studies reported here use a recently developed murine model of ETEC intestinal colonization to examine the immunogenicity and protective efficacy of EtpA. We report that mice repeatedly exposed to ETEC are protected from subsequent colonization and that they mount immune responses to both EtpA and its presumed two-partner secretion transporter (EtpB) during the course of experimental infection. Furthermore, isogenic
etpA
deletion mutants were impaired in the colonization of mice, and intranasal immunization of mice with recombinant EtpA conferred protection against ETEC H10407 in this model. Together, these data suggest that EtpA is required for optimal colonization of the intestine, findings paralleling those of previous in vitro studies demonstrating its role in adherence. EtpA and other TPS proteins may be viable targets for ETEC vaccine development.