bluuebunny/crossref_metadata_2025_split huggingface dataset:
γ-Glutamyl Spermine Synthetase PauA2 as a Potential Target of Antibiotic Development against Pseudomonas aeruginosa
Authors: Yao Xiangyu , Li Congran , Zhang Jianmei , Lu Chung-Dar 
Published: August 2012

ABSTRACT

Polyamines are absolute requirements for cell growth. When in excess,
Pseudomonas aeruginosa
possesses six γ-glutamylpolyamine synthetases (GPSs) encoded by the
pauA1-pauA7
genes to initiate polyamine catabolism. Recently, the
pauA2
mutant was reported to lose the capability to grow on spermine (Spm) and spermidine (Spd) as sole carbon and nitrogen sources. Although this mutant grew normally in defined minimal medium and LB broth, growth was completely abolished by the addition of Spm or Spd. These two compounds exert a bactericidal effect (Spm > Spd) on the mutants as demonstrated by MIC measurements (over 500-fold reduction) and time-killing curves. Spm toxicity in the
pauA2
mutant was attenuated when the major uptake system was further deleted from the strain, suggesting cytoplasmic targets of toxicity. In addition, the synergistic effect of Spm and carbenicillin in the wild-type strain PAO1 was diminished in mutants without functional PauA2. Furthermore, Spm MIC was reduced by 8-fold when the Spm uptake system was deleted from the wild-type strain, suggesting a second target of Spm toxicity in the periplasm. Experiments were also conducted to test the hypothesis that native Spm and Spd in human serum may be sufficient to kill the
pauA2
mutant. Growth of the mutant was completely inhibited by 40% (vol/vol) human serum, whereas the parental strain required 80%. Colony counts indicated that the mutant but not the parent was in fact killed by human plasma. In addition, carbenicillin MIC against the mutant was reduced by 16-fold in the presence of 20% human serum while that of the parental strain remained unchanged. Taking PauA2 as the template, sequence comparison indicates that putative PauA2 homologues are widespread in a variety of Gram-negative bacteria. In summary, this study reveals the importance of GPS in alleviation of polyamine toxicity when in excess, and it provides strong support to the feasibility of GPS as a molecular target for new antibiotic development.
Isolation and Quantitation of Topoisomerase Complexes Accumulated on Escherichia coli Chromosomal DNA
Authors: Aedo Sandra , Tse-Dinh Yuk-Ching 
Published: August 2012

ABSTRACT

DNA topoisomerases are important targets in anticancer and antibacterial therapy because drugs can initiate cell death by stabilizing the transient covalent topoisomerase-DNA complex. In this study, we employed a method that uses CsCl density gradient centrifugation to separate unbound from DNA-bound GyrA/ParC in
Escherichia coli
cell lysates after quinolone treatment, allowing antibody detection and quantitation of the covalent complexes on slot blots. Using these procedures modified from the
in vivo
complexes of enzyme (ICE) bioassay, we found a correlation between gyrase-DNA complex formation and DNA replication inhibition at bacteriostatic (1× MIC) norfloxacin concentrations. Quantitation of the number of gyrase-DNA complexes per
E. coli
cell permitted an association between cell death and chromosomal gyrase-DNA complex accumulation at norfloxacin concentrations greater than 1× MIC. When comparing levels of gyrase-DNA complexes to topoisomerase IV-DNA complexes in the absence of drug, we observed that the gyrase-DNA complex level was higher (∼150-fold) than that of the topoisomerase IV-DNA complex. In addition, levels of gyrase and topoisomerase IV complexes reached a significant increase after 30 min of treatment at 1× and 1.7× MIC, respectively. These results are in agreement with gyrase being the primary target for quinolones in
E. coli
. We further validated the utility of this method for the study of topoisomerase-drug interactions in bacteria by showing the gyrase covalent complex reversibility after removal of the drug from the medium, and the resistant effect of the Ser83Leu
gyrA
mutation on accumulation of gyrase covalent complexes on chromosomal DNA.
DNA Microarray Profiling of a Diverse Collection of Nosocomial Methicillin-Resistant Staphylococcus aureus Isolates Assigns the Majority to the Correct Sequence Type and Staphylococcal Cassette Chromosome
mec
(SCC
mec
) Type and Results in the Subsequent Identification and Characterization of Novel SCC
mec
-SCC
M1
Composite Islands
Authors: Shore Anna C. , Brennan Orla M. , Deasy Emily C. , Rossney Angela S. , Kinnevey Peter M. , Ehricht Ralf , Monecke Stefan , Coleman David C. 
Published: August 2012

ABSTRACT

One hundred seventy-five isolates representative of methicillin-resistant
Staphylococcus aureus
(MRSA) clones that predominated in Irish hospitals between 1971 and 2004 and that previously underwent multilocus sequence typing (MLST) and staphylococcal cassette chromosome
mec
(SCC
mec
) typing were characterized by
spa
typing (175 isolates) and DNA microarray profiling (107 isolates). The isolates belonged to 26 sequence type (ST)-SCC
mec
types and subtypes and 35
spa
types. The array assigned all isolates to the correct MLST clonal complex (CC), and 94% (100/107) were assigned an ST, with 98% (98/100) correlating with MLST. The array assigned all isolates to the correct SCC
mec
type, but subtyping of only some SCC
mec
elements was possible. Additional SCC
mec/
SCC genes or DNA sequence variation not detected by SCC
mec
typing was detected by array profiling, including the SCC-fusidic acid resistance determinant Q6GD50/
fusC
. Novel SCC
mec
/SCC composite islands (CIs) were detected among CC8 isolates and comprised SCC
mec
IIA-IIE, IVE, IVF, or IVg and a
ccrAB4
-SCC element with 99% DNA sequence identity to SCC
M1
from ST8/t024-MRSA, SCC
mec
VIII, and SCC-CI in
Staphylococcus epidermidis
. The array showed that the majority of isolates harbored one or more superantigen (94%; 100/107) and immune evasion cluster (91%; 97/107) genes. Apart from fusidic acid and trimethoprim resistance, the correlation between isolate antimicrobial resistance phenotype and the presence of specific resistance genes was ≥97%. Array profiling allowed high-throughput, accurate assignment of MRSA to CCs/STs and SCC
mec
types and provided further evidence of the diversity of SCC
mec
/SCC. In most cases, array profiling can accurately predict the resistance phenotype of an isolate.
Efficient Replication of Genotype 3a and 4a Hepatitis C Virus Replicons in Human Hepatoma Cells
Authors: Saeed Mohsan , Scheel Troels K. H. , Gottwein Judith M. , Marukian Svetlana , Dustin Lynn B. , Bukh Jens , Rice Charles M. 
Published: August 2012

ABSTRACT

Despite recent advances in the treatment of hepatitis C, the quest for pan-genotype, effective, and well-tolerated inhibitors continues. To facilitate these efforts, it is desirable to have
in vitro
replication systems for all major HCV genotypes. However, cell culture replication systems exist for only genotypes 1a, 1b, and 2a. In this study, we generated G418-selectable subgenomic replicons for prototype strains of genotypes 3a (S52) and 4a (ED43). Production of G418-resistant colonies by S52 and ED43 in Huh-7.5 cells required the amino acid substitutions S2210I and R2882G, respectively, cell culture adaptive mutations originally reported for genotype 1b replicons. RNA replication was confirmed by quantitative reverse transcription-PCR and detection of viral protein. Sequencing of multiple independent replicon clones revealed the presence of additional nonsynonymous mutations. Interestingly, all potentially adaptive mutations mapped to the NS3 protein. These mutations, when introduced back into original constructs, substantially increased colony formation efficiency. To make these replicons useful for high-throughput screening and evaluation of antiviral compounds, they were modified to express a chimeric fusion protein of firefly luciferase and neomycin phosphotransferase to yield stable replicon-expressing cells. Using these constructs, the inhibitory effects of beta interferon (IFN-β), an NS3 protease inhibitor, and an NS5B nucleoside polymerase inhibitor were readily detected by monitoring luciferase activity. In conclusion, we have established functional replicons for HCV genotypes 3a and 4a, important new additions to the armamentarium required to develop inhibitors with a pan-genotype activity.
Hemophagocytic Macrophages in Murine Typhoid Fever Have an Anti-Inflammatory Phenotype
Authors: McCoy Melissa W. , Moreland Sarah M. , Detweiler Corrella S. 
Published: August 2012

ABSTRACTHistiocytes are white blood cells of the monocytic lineage and include macrophages and dendritic cells. In patients with a variety of infectious and noninfectious inflammatory disorders, histiocytes can engulf nonapoptotic leukocytes and nonsenescent erythrocytes and thus become hemophagocytes. We report here the identification and characterization of splenic hemophagocytes in a natural model of murine typhoid fever. The development of a flow-cytometric method allowed us to identify hemophagocytes based on their greater than 6N (termed 6N+) DNA content. Characterization of the 6N+ population from infected mice showed that these cells consist primarily of macrophages rather than dendritic cells and contain T lymphocytes, consistent with hemophagocytosis. Most 6N+ macrophages fromSalmonella entericaserovar Typhimurium-infected mice contain intact DNA, consistent with hemophagocytosis. In contrast, most 6N+ macrophages from control mice or mice infected with a different bacterial pathogen,Yersinia pseudotuberculosis, contain damaged DNA. Finally, 6N+ splenic macrophages fromS. Typhimurium-infected mice express markers consistent with an anti-inflammatory M2 activation state rather than a classical M1 activation state. We conclude that macrophages are the predominant splenic hemophagocyte in this disease model but not inY. pseudotuberculosis-infected mice. The anti-inflammatory phenotype of hemophagocytic macrophages suggests that these cells contribute to the shift from acute to chronic infection.
Accumulation of Myeloid-Derived Suppressor Cells in the Lungs during Pneumocystis Pneumonia
Authors: Zhang Chen , Lei Guang-Sheng , Shao Shoujin , Jung Hsin-Wei , Durant Pamela J. , Lee Chao-Hung 
Published: August 2012

ABSTRACTMyeloid-derived suppressor cells (MDSCs) are a heterogeneous population of hematopoietic precursors with the ability to adversely affect host immunity. They have been shown to accumulate in pathological conditions, such as cancer and some microbial diseases. In the mouse and rat models ofPneumocystispneumonia (PcP), we found a distinct population of cells with MDSC-like morphology in the bronchoalveolar lavage (BAL) fluid, constituting up to 50% of the total cells in BAL fluid. These cells were not seen in the BAL fluid from normal animals or fromPneumocystis-infected animals that had been successfully treated for PcP with a combination of trimethoprim and sulfamethoxazole. With flow cytometry, these cells were found to express the characteristic MDSC surface markers Gr-1 and CD11b in mice or CD11bc and His48 in rats. Using reverse transcription-PCR, we demonstrated that these cells produced high levels of arginase-1 and inducible nitric oxide synthase (iNOS) mRNA. These cells were shown to suppress CD4+T-cell proliferation in response to stimulation by anti-CD3 and anti-CD28 antibodies. Adoptive transfer of these cells to normal mice caused lung damage, as indicated by elevated levels of albumin and lactate dehydrogenase in the BAL fluid. These experiments provide evidence of the presence of MDSCs in the lungs during PcP. Further studies on the roles of MDSCs in PcP are warranted in order to develop treatment strategies which can reduce the number of MDSCs and the damage caused by these cells.
Effectiveness of an injury prevention programme for adult male amateur soccer players: a cluster-randomised controlled trial
Authors: van Beijsterveldt Anna M C , van de Port Ingrid G L , Krist Mark R , Schmikli Sandor L , Stubbe Janine H , Frederiks Janet E , Backx Frank J G 
Published: August 2012

BackgroundThe incidence rate of soccer injuries is among the highest in sports, particularly for adult male soccer players.PurposeTo investigate the effect of the ‘The11’ injury prevention programme on injury incidence and injury severity in adult male amateur soccer players.Study designCluster-randomised controlled trial.MethodsTeams from two high-level amateur soccer competitions were randomly assigned to an intervention (n=11 teams, 223 players) or control group (n=12 teams, 233 players). The intervention group was instructed to perform The11 in each practice session during one soccer season. The11 focuses on core stability, eccentric training of thigh muscles, proprioceptive training, dynamic stabilisation and plyometrics with straight leg alignment. All participants of the control group continued their practice sessions as usual.ResultsIn total, 427 injuries were recorded, affecting 274 of 456 players (60.1%). Compliance with the intervention programme was good (team compliance=73%, player compliance=71%). Contrary to the hypothesis, injury incidences were almost equal between the two study groups: 9.6 per 1000 sports hours (8.4–11.0) for the intervention group and 9.7 (8.5–11.1) for the control group. No significant differences were found in injury severity, but a significant difference was observed in the location of the injuries: players in the intervention group sustained significantly less knee injuries.ConclusionsThis study did not find significant differences in the overall injury incidence or injury severity between the intervention and control group of adult male soccer players. More research is recommended, focusing on injury aetiology and risk factors in adult male amateur soccer players.
Candida parapsilosiscandidaemia in a neonatal unit over 7 years: a case series study
Authors: Miranda Lourdes das Neves , Rodrigues Eliete C A , Costa Silvia F , van der Heijden Inneke Marie , Dantas Kátia C , Lobo Renata D , Basso Mariusa , Varkulja Gláucia F , Krebs Vera Lúcia Jornada , Gibelli Maria Augusta Bento Cicaroni , Criado Paulo R , Levin Anna Sara 
Published: August 2012

ObjectiveTo evaluateCandida parapsilosiscandidaemia in a neonatal unit over 7 years.DesignCase series study.SettingA 2000-bed tertiary-care university hospital at São Paulo, Brazil.ParticipantsNeonates hospitalised in a 63-bed neonatal unit.Primary and secondary outcome measuresWe evaluated the incidence ofC parapsilosisfungemia in a neonatal unit from 2002 through 2008 and the main microbiological, clinical and epidemiological aspects of this disease in neonates. During the study period an outbreak occurred, an infection control programme was implemented, and isolates from blood and hand healthcare workers (HCWs) were submitted to molecular typing.ResultsDuring 7 years, there were 36 cases ofC parapsilosisfungaemia and annual incidence varied from 0 to 19.7 per 1000 admissions. Evaluating 31 neonates with fungemia, the mean age at diagnosis was 19 days. All children except for one were premature; all had received total parenteral nutrition and all but one had used central venous catheter. Three neonates had received antifungal treatment previously to the diagnosis. Thirty-day mortality was 45%. Only lower birthweight was associated with mortality.C parapsilosisspecies complex was isolated from hand cultures in eight (11%) of the HCWs (one isolate was identified asC orthopsilosis). By molecular typing no HCW isolate was similar to any of the blood isolates.ConclusionsThe incidence ofC parapsilosisfungemia in a neonatal unit varied widely over 7 years. We observed in our series a higher death rate than that reported in European countries and the USA.
Alcohol: signs of improvement. The 2nd national Emergency Department survey of alcohol identification and intervention activity
Authors: Patton Robert , O'Hara Pat 
Published: August 2012

ObjectivesTo conduct a survey of current alcohol identification and brief advice activity in English Emergency Departments, and to compare the results with the previous survey conducted in 2007.MethodologyCross-sectional survey of all 187 Emergency Departments in England.ResultsSignificant increases (p<0.001) in the proportion of departments routinely asking about alcohol, using a screening questionnaire, offering help/advice for alcohol problems, and having access to Alcohol Health Workers or Clinical Nurse Specialists. More than half of all departments indicated that they had an ‘alcohol champion’, and this was significantly associated with access to training on both identification and provision of brief advice (p<0.001). Departments that routinely asked questions were the most likely to use a formal screening tool (p<0.05), and the Paddington Alcohol Test was the most frequently used measure (40.5%).ConclusionsThere have been significant improvements in ED alcohol identification and brief advice activity since 2007 in line with the recommendations of the Royal College of Physicians, Department of Health and NICE guidelines. English EDs are beginning to maximise the likelihood of identifying patients who may benefit from further help or advice about their alcohol consumption, and are able to offer access to specialist staff who can provide appropriate interventions.
The role of poverty in explaining health variations in 7-year-old children from different family structures: findings from the UK Millennium Cohort Study
Authors: Pearce Anna , Lewis Hannah , Law Catherine 
Published: August 2012

BackgroundDespite rises in reconstituted and lone-parent families, relatively little is known about how the health of children in different family types varies, and the extent to which any differences might be explained by poverty. The authors examined this using cross-sectional data on 13 681 seven-year-olds from the Millennium Cohort Study.MethodsThe authors estimated RRs and 95% CIs for having poor physical (general health, long-standing illness, injury, overweight, asthma, fits) and mental health (using strengths and difficulties scores) according to family structure using Poisson regression. The authors adjusted for confounders (aRR) and then investigated the role of poverty as a mediator by entering a poverty score (based on income, receipt of benefits, subjective poverty and material deprivation) into the main model.ResultsChildren living in reconstituted and lone-parent families were at a slight increased risk of poor health compared with those living with two natural parents. Adjusting for poverty tended to remove the elevated risk of poor physical health in children living in lone-parent and reconstituted families. However, for the mental health outcomes, poverty tended to remove the elevated risk for lone parents but not for reconstituted families. For example, the aRR for borderline–abnormal total difficulties fell from 1.45 (1.22 to 1.72) to 1.34 (1.13 to 1.59) in children living in reconstituted families and from 1.29 (1.14 to 1.45) to 1.05 (0.92 to 1.19) in those living with lone parents.ConclusionsPoor physical and mental health was slightly more prevalent in children living in lone-parent or reconstituted families. Poverty reduction may help to reduce these differences, especially for children living with lone parents; however, alternative mechanisms should be also explored, particularly for children living in reconstituted families.
AN ENTROPY BASED IN WAVELET LEADERS TO QUANTIFY THE LOCAL REGULARITY OF A SIGNAL AND ITS APPLICATION TO ANALIZE THE DOW JONES INDEX
Authors: ROSENBLATT MARIEL , SERRANO EDUARDO , FIGLIOLA ALEJANDRA 
Published: August 2012

Local regularity analysis is useful in many fields, such as financial analysis, fluid mechanics, PDE theory, signal and image processing. Different quantifiers have been proposed to measure the local regularity of a function. In this paper we present a new quantifier of local regularity of a signal: the pointwise wavelet leaders entropy. We define this new measure of regularity by combining the concept of entropy, coming from the information theory and statistical mechanics, with the wavelet leaders coefficients. Also we establish its inverse relation with one of the well-known regularity exponents, the pointwise Hölder exponent. Finally, we apply this methodology to the financial data series of the Dow Jones Industrial Average Index, registered in the period 1928–2011, in order to compare the temporal evolution of the pointwise Hölder exponent and the pointwise wavelet leaders entropy. The analysis reveals that temporal variation of these quantifiers reflects the evolution of the Dow Jones Industrial Average Index and identifies historical crisis events. We propose a new approach to analyze the local regularity variation of a signal and we apply this procedure to a financial data series, attempting to make a contribution to understand the dynamics of financial markets.
Prohibitin Attenuates Colitis-Associated Tumorigenesis in Mice by Modulating p53 and STAT3 Apoptotic Responses
Authors: Kathiria Arwa S. , Neumann William L. , Rhees Jennifer , Hotchkiss Erin , Cheng Yulan , Genta Robert M. , Meltzer Stephen J. , Souza Rhonda F. , Theiss Arianne L. 
Published: August 2012

Abstract
Although inflammatory bowel disease is associated with higher risk of colorectal cancer, the precise pathogenic mechanisms underlying this association are not completely understood. Prohibitin 1 (PHB), a protein implicated in the regulation of proliferation, apoptosis, and transcription, is decreased in intestinal inflammation. In this study, we have established a key function for PHB in mediating colitis-associated cancer. Wild-type and transgenic (Tg) mice specifically overexpressing PHB in intestinal epithelial cells were subjected to a classical two-stage protocol of colitis-associated carcinogenesis. In addition, wild-type and p53 null human cell models were used to assess PHB interaction with STAT3 and p53. Wild-type mice exhibited decreased mucosal PHB protein expression during colitis-associated carcinogenesis. Tg mice exhibited decreased susceptibility in a manner associated with increased apoptosis, p53, Bax, and Bad expression plus decreased Bcl-xL and Bcl-2 expression. PHB overexpression in wild-type but not p53 null human cells increased expression of Bax, Bad, and caspase-3 cleavage. In wild-type p53 cells, PHB overexpression decreased basal and interleukin-6-induced STAT3 activation and expression of the STAT3 responsive genes Bcl-xL and Bcl-2. PHB coimmunoprecipitated with phospho-STAT3 in addition to p53 in cultured cell lysates and colon mucosa. This is the first study to show interaction between PHB and STAT3 in vivo. In summary, our findings suggest that PHB protects against colitis-associated cancer by modulating p53- and STAT3-mediated apoptosis. Modulation of PHB expression in intestinal epithelial cells may offer a potential therapeutic approach to prevent colitis-associated carcinogenesis. Cancer Res; 72(22); 5778–89. ©2012 AACR.