bluuebunny/crossref_metadata_2025 huggingface dataset:
Emergence of Resistance to Atovaquone-Proguanil in Malaria Parasites: Insights from Computational Modeling and Clinical Case Reports
Authors: Cottrell Gilles , Musset Lise , Hubert Véronique , Le Bras Jacques , Clain Jérôme
Published: May 2014

The usefulness of atovaquone-proguanil (AP) as an antimalarial treatment is compromised by the emergence of atovaquone resistance during therapy. However, the origin of the parasite mitochondrial DNA (mtDNA) mutation conferring atovaquone resistance remains elusive. Here, we report a patient-based stochastic model that tracks the intrahost emergence of mutations in the multicopy mtDNA during the first erythrocytic parasite cycles leading to the malaria febrile episode. The effect of mtDNA copy number, mutation rate, mutation cost, and total parasite load on the mutant parasite load per patient was evaluated. Computer simulations showed that almost any infected patient carried, after four to seven erythrocytic cycles,
de novo
mutant parasites at low frequency, with varied frequencies of parasites carrying varied numbers of mutant mtDNA copies. A large interpatient variability in the size of this mutant reservoir was found; this variability was due to the different parameters tested but also to the relaxed replication and partitioning of mtDNA copies during mitosis. We also report seven clinical cases in which AP-resistant infections were treated by AP. These provided evidence that parasiticidal drug concentrations against AP-resistant parasites were transiently obtained within days after treatment initiation. Altogether, these results suggest that each patient carries new mtDNA mutant parasites that emerge before treatment but are killed by high starting drug concentrations. However, because the size of this mutant reservoir is highly variable from patient to patient, we propose that some patients fail to eliminate all of the mutant parasites, repeatedly producing
de novo
AP treatment failures.
Population Pharmacokinetics and Clinical Response for Artemether-Lumefantrine in Pregnant and Nonpregnant Women with Uncomplicated Plasmodium falciparum Malaria in Tanzania
Authors: Mosha Dominic , Guidi Monia , Mwingira Felista , Abdulla Salim , Mercier Thomas , Decosterd Laurent Arthur , Csajka Chantal , Genton Blaise
Published: May 2014

Artemether-lumefantrine (AL) is the first-line treatment for uncomplicated malaria in the second and third trimesters of pregnancy. Its efficacy during pregnancy has recently been challenged due to altered pharmacokinetic (PK) properties in this vulnerable group. The aim of this study was to determine the PK profile of AL in pregnant and nonpregnant women and assess their therapeutic outcome. Thirty-three pregnant women and 22 nonpregnant women with malaria were treated with AL (80/480 mg) twice daily for 3 days. All patients provided five venous plasma samples for drug quantification at random times over 7 days. Inter- and intraindividual variability was assessed, and the effects of covariates were quantified using a nonlinear mixed-effects modeling approach (NONMEM). A one-compartment model with first-order absorption and elimination with linear metabolism from drug to metabolite fitted the data best for both arthemether (AM) and lumefantrine (LF) and their metabolites. Pregnancy status and diarrhea showed a significant influence on LF PK. The relative bioavailability of lumefantrine and its metabolism rate into desmethyl-lumefantrine were, respectively, 34% lower and 78% higher in pregnant women than in nonpregnant patients. The overall PCR-uncorrected treatment failure rates were 18% in pregnant women and 5% in nonpregnant women (odds ratio [OR] = 4.04;
P
value of 0.22). A high median day 7 lumefantrine concentration was significantly associated with adequate clinical and parasitological response (
P
= 0.03). The observed reduction in the relative bioavailability of lumefantrine in pregnant women may explain the higher treatment failure in this group, mostly due to lower posttreatment prophylaxis. Hence, a modified treatment regimen of malaria in pregnancy should be considered.
In Vivo
and
In Vitro
Acquisition of Resistance to Voriconazole by Candida krusei
Authors: Ricardo Elisabete , Miranda Isabel M. , Faria-Ramos Isabel , Silva Raquel M. , Rodrigues Acácio Gonçalves , Pina-Vaz Cidália
Published: May 2014

Candida krusei
is an important agent of opportunistic infections that often displays resistance to several antifungals. We describe here the
in vivo
acquisition of resistance to voriconazole (VRC) by
C. krusei
isolates recovered from a leukemia patient during a long period of VRC therapy. In order to mimic the
in vivo
development of VRC resistance, a susceptible
C. krusei
isolate was exposed daily to 1 μg/ml of VRC
in vitro
. Interestingly, after 5 days of exposure to VRC, a MIC of 4 μg/ml was achieved; this value remained constant after 25 additional days of treatment with VRC and also after 30 consecutive days of incubation in VRC-free medium. Our objective was to determine the associated molecular resistance mechanisms, such as expression of efflux pump genes and
ERG11
gene mutations, among the resistant strains. Synergistic effects between the efflux blocker tacrolimus (FK506) and VRC were found in all of the resistant strains. Moreover,
ABC1
gene expression increased over time in both the
in vivo
- and
in vitro
-induced resistant strains, in contrast to the
ABC2
and
ERG11
genes, whose expression was invariably lower and constant.
ERG11
gene sequencing showed two different types of mutations, i.e., heterozygosity at T1389T/C, corresponding to synonymous mutations, in
C. krusei
strains and a missense mutation at position T418C, resulting in a change from Tyr to His, among resistant
C. krusei
clinical isolates. This study highlights the relevance of ATP-dependent efflux pump (namely, Abc1p) activity in VRC resistance and describes new mutations in the
ERG11
gene among resistant
C. krusei
clinical isolates.
Eight More Ways To Deal with Antibiotic Resistance
Authors: Metz Matthew , Shlaes David M.
Published: May 2014

The fight against antibiotic resistance must be strengthened. We propose actions that U.S. government agencies and private sector entities can take to build a more comprehensive effort. These actions can increase the viability of investing in new antibiotics, ensure the quality and stewardship of all antibiotics, and make responses to emerging resistance more informed. Success requires the thoughtful exercise of federal authority and a firm commitment to share data and reward developers for the value generated with new, life-saving antibiotics.
Extended-Infusion versus Standard-Infusion Piperacillin-Tazobactam for Sepsis Syndromes at a Tertiary Medical Center
Authors: Cutro Scott R. , Holzman Robert , Dubrovskaya Yanina , Chen Xian Jie Cindy , Ahuja Tania , Scipione Marco R. , Chen Donald , Papadopoulos John , Phillips Michael S. , Mehta Sapna A.
Published: May 2014

Piperacillin-tazobactam (PTZ) is frequently used as empirical and targeted therapy for Gram-negative sepsis. Time-dependent killing properties of PTZ support the use of extended-infusion (EI) dosing; however, studies have shown inconsistent benefits of EI PTZ treatment on clinical outcomes. We performed a retrospective cohort study of adult patients who received EI PTZ treatment and historical controls who received standard-infusion (SI) PTZ treatment for presumed sepsis syndromes. Data on mortality rates, clinical outcomes, length of stay (LOS), and disease severity were obtained. A total of 843 patients (662 with EI treatment and 181 with SI treatment) were available for analysis. Baseline characteristics of the two groups were similar, except for fewer female patients receiving EI treatment. No significant differences between the EI and SI groups in inpatient mortality rates (10.9% versus 13.8%;
P
= 0.282), overall LOS (10 versus 12 days;
P
= 0.171), intensive care unit (ICU) LOS (7 versus 6 days;
P
= 0.061), or clinical failure rates (18.4% versus 19.9%;
P
= 0.756) were observed. However, the duration of PTZ therapy was shorter in the EI group (5 versus 6 days;
P
< 0.001). Among ICU patients, no significant differences in outcomes between the EI and SI groups were observed. Patients with urinary or intra-abdominal infections had lower mortality and clinical failure rates when receiving EI PTZ treatment. We did not observe significant differences in inpatient mortality rates, overall LOS, ICU LOS, or clinical failure rates between patients receiving EI PTZ treatment and patients receiving SI PTZ treatment. Patients receiving EI PTZ treatment had a shorter duration of PTZ therapy than did patients receiving SI treatment, and EI dosing may provide cost savings to hospitals.
In Vitro
Activity and Resistance Profile of Samatasvir, a Novel NS5A Replication Inhibitor of Hepatitis C Virus
Authors: Bilello J. P. , Lallos L. B. , McCarville J. F. , La Colla M. , Serra I. , Chapron C. , Gillum J. M. , Pierra C. , Standring D. N. , Seifer M.
Published: May 2014

The hepatitis C virus (HCV) nonstructural 5A (NS5A) protein is a clinically validated target for drugs designed to treat chronic HCV infection. This study evaluated the
in vitro
activity, selectivity, and resistance profile of a novel anti-HCV compound, samatasvir (IDX719), alone and in combination with other antiviral agents. Samatasvir was effective and selective against infectious HCV and replicons, with 50% effective concentrations (EC
50
s) falling within a tight range of 2 to 24 pM in genotype 1 through 5 replicons and with a 10-fold EC
50
shift in the presence of 40% human serum in the genotype 1b replicon. The EC
90
/EC
50
ratio was low (2.6). A 50% cytotoxic concentration (CC
50
) of >100 μM provided a selectivity index of >5 × 10
7
. Resistance selection experiments (with genotype 1a replicons) and testing against replicons bearing site-directed mutations (with genotype 1a and 1b replicons) identified NS5A amino acids 28, 30, 31, 32, and 93 as potential resistance loci, suggesting that samatasvir affects NS5A function. Samatasvir demonstrated an overall additive effect when combined with interferon alfa (IFN-α), ribavirin, representative HCV protease, and nonnucleoside polymerase inhibitors or the nucleotide prodrug IDX184. Samatasvir retained full activity in the presence of HIV and hepatitis B virus (HBV) antivirals and was not cross-resistant with HCV protease, nucleotide, and nonnucleoside polymerase inhibitor classes. Thus, samatasvir is a selective low-picomolar inhibitor of HCV replication
in vitro
and is a promising candidate for future combination therapies with other direct-acting antiviral drugs in HCV-infected patients.
Flow Cytometry-Based Analysis of Artemisinin-Resistant Plasmodium falciparum in the Ring-Stage Survival Assay
Authors: Amaratunga Chanaki , Neal Aaron T. , Fairhurst Rick M.
Published: May 2014

The ring-stage survival assay (RSA) is a powerful tool for phenotyping artemisinin-resistant
Plasmodium falciparum
but requires experienced microscopists to count viable parasites among 10,000 erythrocytes in Giemsa-stained thin blood smears. Here we describe a rapid flow cytometric assay that accurately counts viable parasites among 250,000 erythrocytes in suspension. This method performs as well as light microscopy and can be used to standardize the collection of RSA data between research groups in laboratory and field settings.
Decreased Ceftriaxone Susceptibility in Emerging (35B and 6C) and Persisting (19A) Streptococcus pneumoniae Serotypes in the United States, 2011-2012: Ceftaroline Remains Active
In Vitro
among β-Lactam Agents
Authors: Mendes Rodrigo E. , Biek Donald , Critchley Ian A. , Farrell David J. , Sader Helio S. , Jones Ronald N.
Published: May 2014

Totals of 8.7% (103/1,190) and 21.0% (249/1,190) of the
Streptococcus pneumoniae
isolates recovered from specimens collected in the United States during the 2011-2012 AWARE (
A
ssessing
W
orldwide
A
ntimicrobial
R
esistance
E
valuation) Surveillance Program were ceftriaxone nonsusceptible according to the CLSI (≤1 μg/ml for susceptible) and EUCAST (≤0.5 μg/ml for susceptible) criteria, respectively. Decreased susceptibility to ceftriaxone (MIC, 1 μg/ml) was frequently observed among serotypes 19A (51.4%; 128/249) and 35B (29.7%; 74/249), which were most often observed in the East South Central and South Atlantic U.S. Census regions. Ceftaroline (MIC
50/90
, 0.12/0.25 μg/ml) remained active (≥96.8% susceptible) when tested against these less susceptible isolates.
Development and Characterization of a Long-Term Murine Model of Streptococcus pneumoniae Infection of the Lower Airways
Authors: Haste Louise , Hulland Kathryn , Bolton Sarah , Yesilkaya Hasan , McKechnie Kenneth , Andrew Peter W.
Published: May 2014

Chronic obstructive pulmonary disease (COPD) is characterized by long periods of stable symptoms, but exacerbations occur, which result in a permanent worsening of symptoms. Previous studies have shown a link between bacterial colonization of the lower airways of COPD sufferers and an increase in exacerbation frequency. One of the most frequent bacterial colonizers isStreptococcus pneumoniae. To mimic this aspect of COPD, a murine model of low-level pneumococcal colonization in the lung has been developed, in whichS. pneumoniaepersisted in the lungs for at least 28 days. From day 14 postinfection, bacterial numbers remained constant until at least 28 days postinfection, and animals showed no outward signs of disease. The bacterial presence correlated with a low-level inflammatory response that was localized to small foci across the left and inferior lobes of the lung. The cellular response was predominantly monocytic, and focal fibroplasia was observed at the airway transitional zones. Physiological changes in the lungs were investigated with a Forced Maneuvers system. This new model provides a means of study of a long-term pulmonary infection with a human pathogen in a rodent system. This is an excellent tool for the development of future models that mimic complex respiratory diseases such as COPD and asthma.
Proteome Analysis of Coinfection of Epithelial Cells with Filifactor alocis and Porphyromonas gingivalis Shows Modulation of Pathogen and Host Regulatory Pathways
Authors: Aruni A. Wilson , Zhang Kangling , Dou Yuetan , Fletcher Hansel
Published: May 2014

Changes in periodontal status are associated with shifts in the composition of the bacterial community in the periodontal pocket. The relative abundances of several newly recognized microbial species, including
Filifactor alocis
, as-yet-unculturable organisms, and other fastidious organisms have raised questions on their impact on disease development. We have previously reported that the virulence attributes of
F. alocis
are enhanced in coculture with
Porphyromonas gingivalis
. We have evaluated the proteome of host cells and
F. alocis
during a polymicrobial infection. Coinfection of epithelial cells with
F. alocis
and
P. gingivalis
strains showed approximately 20% to 30% more proteins than a monoinfection. Unlike
F. alocis
ATCC 35896, the D-62D strain expressed more proteins during coculture with
P. gingivalis
W83 than with
P. gingivalis
33277. Proteins designated microbial surface component-recognizing adhesion matrix molecules (MSCRAMMs) and cell wall anchor proteins were highly upregulated during the polymicrobial infection. Ultrastructural analysis of the epithelial cells showed formation of membrane microdomains only during coinfection. The proteome profile of epithelial cells showed proteins related to cytoskeletal organization and gene expression and epigenetic modification to be in high abundance. Modulation of proteins involved in apoptotic and cell signaling pathways was noted during coinfection. The enhanced virulence potential of
F. alocis
may be related to the differential expression levels of several putative virulence factors and their effects on specific host cell pathways.
Proteomic Analysis of the Burkholderia pseudomallei Type II Secretome Reveals Hydrolytic Enzymes, Novel Proteins, and the Deubiquitinase TssM
Authors: Burtnick Mary N. , Brett Paul J. , DeShazer David
Published: May 2014

Burkholderia pseudomallei
, the etiologic agent of melioidosis, is an opportunistic pathogen that harbors a wide array of secretion systems, including a type II secretion system (T2SS), three type III secretion systems (T3SS), and six type VI secretion systems (T6SS). The proteins exported by these systems provide
B. pseudomallei
with a growth advantage
in vitro
and
in vivo
, but relatively little is known about the full repertoire of exoproducts associated with each system. In this study, we constructed deletion mutations in
gspD
and
gspE
, T2SS genes encoding an outer membrane secretin and a cytoplasmic ATPase, respectively. The secretion profiles of
B. pseudomallei
MSHR668 and its T2SS mutants were noticeably different when analyzed by SDS-PAGE. We utilized liquid chromatography-tandem mass spectrometry (LC-MS/MS) to identify proteins present in the supernatants of
B. pseudomallei
MSHR668 and
B. pseudomallei
Δ
gspD
grown in rich and minimal media. The MSHR668 supernatants contained 48 proteins that were either absent or substantially reduced in the supernatants of Δ
gspD
strains. Many of these proteins were putative hydrolytic enzymes, including 12 proteases, two phospholipases, and a chitinase. Biochemical assays validated the LC-MS/MS results and demonstrated that the export of protease, phospholipase C, and chitinase activities is T2SS dependent. Previous studies had failed to identify the mechanism of secretion of TssM, a deubiquitinase that plays an integral role in regulating the innate immune response. Here we present evidence that TssM harbors an atypical signal sequence and that its secretion is mediated by the T2SS. This study provides the first in-depth characterization of the
B. pseudomallei
T2SS secretome.
Burkholderia pseudomallei Capsular Polysaccharide Conjugates Provide Protection against Acute Melioidosis
Authors: Scott Andrew E. , Burtnick Mary N. , Stokes Margaret G. M. , Whelan Adam O. , Williamson E. Diane , Atkins Timothy P. , Prior Joann L. , Brett Paul J.
Published: May 2014

Burkholderia pseudomallei, the etiologic agent of melioidosis, is a CDC tier 1 select agent that causes severe disease in both humans and animals. Diagnosis and treatment of melioidosis can be challenging, and in the absence of optimal chemotherapeutic intervention, acute disease is frequently fatal. Melioidosis is an emerging infectious disease for which there are currently no licensed vaccines. Due to the potential malicious use ofB. pseudomalleias well as its impact on public health in regions where the disease is endemic, there is significant interest in developing vaccines for immunization against this disease. In the present study, type A O-polysaccharide (OPS) andmanno-heptose capsular polysaccharide (CPS) antigens were isolated from nonpathogenic, select-agent-excluded strains ofB. pseudomalleiand covalently linked to carrier proteins. By using these conjugates (OPS2B1 and CPS2B1, respectively), it was shown that although high-titer IgG responses against the OPS or CPS component of the glycoconjugates could be raised in BALB/c mice, only those animals immunized with CPS2B1 were protected against intraperitoneal challenge withB. pseudomallei. Extending upon these studies, it was also demonstrated that when the mice were immunized with a combination of CPS2B1 and recombinantB. pseudomalleiLolC, rather than with CPS2B1 or LolC individually, they exhibited higher survival rates when challenged with a lethal dose ofB. pseudomallei. Collectively, these results suggest that CPS-based glycoconjugates are promising candidates for the development of subunit vaccines for immunization against melioidosis.
Host Defense Peptide Resistance Contributes to Colonization and Maximal Intestinal Pathology by Crohn's Disease-Associated Adherent-Invasive Escherichia coli
Authors: McPhee Joseph B. , Small Cherrie L. , Reid-Yu Sarah A. , Brannon John R. , Le Moual Hervé , Coombes Brian K.
Published: May 2014

Host defense peptides secreted by colonocytes and Paneth cells play a key role in innate host defenses in the gut. In Crohn's disease, the burden of tissue-associated
Escherichia coli
commonly increases at epithelial surfaces where host defense peptides concentrate, suggesting that this bacterial population might actively resist this mechanism of bacterial killing. Adherent-invasive
E. coli
(AIEC) is associated with Crohn's disease; however, the colonization determinants of AIEC in the inflamed gut are undefined. Here, we establish that host defense peptide resistance contributes to host colonization by Crohn's-associated AIEC. We identified a plasmid-encoded genomic island (called PI-6) in AIEC strain NRG857c that confers high-level resistance to α-helical cationic peptides and α- and β-defensins. Deletion of PI-6 sensitized strain NRG857c to these host defense molecules, reduced its competitive fitness in a mouse model of infection, and attenuated its ability to induce cecal pathology. This phenotype is due to two genes in PI-6,
arlA
, which encodes a Mig-14 family protein implicated in defensin resistance, and
arlC
, an OmpT family outer membrane protease. Implicit in these findings are new bacterial targets whose inhibition might limit AIEC burden and disease in the gut.
Francisella tularensis LVS Induction of Prostaglandin Biosynthesis by Infected Macrophages Requires Specific Host Phospholipases and Lipid Phosphatases
Authors: Navratil Aaron R. , Brummett Ashley M. , Bryan Joshua D. , Woolard Matthew D.
Published: May 2014

Francisella tularensisinduces the synthesis of prostaglandin E2(PGE2) by infected macrophages to alter host immune responses, thus providing a survival advantage to the bacterium. We previously demonstrated that PGE2synthesis byF. tularensis-infected macrophages requires cytosolic phospholipase A2 (cPLA2), cyclooxygenase 2 (COX-2), and microsomal prostaglandin E synthase 1 (mPGES1). During inducible PGE2synthesis, cPLA2hydrolyzes arachidonic acid (AA) from cellular phospholipids to be converted to PGE2. However, inF. tularensis-infected macrophages we observed a temporal disconnect between Ser505-cPLA2phosphorylation (a marker of activation) and PGE2synthesis. These results suggested to us that cPLA2is not responsible for the liberation of AA to be converted into PGE2byF. tularensis-infected macrophages. Utilizing small-molecule inhibitors, we demonstrated that phospholipase D and diacylglycerol lipase were required for providing AA for PGE2biosynthesis. cPLA2, on the other hand, was required for macrophage cytokine responses toF. tularensis. We also demonstrated for the first time that lipin-1 and PAP2a contribute to macrophage inflammation in response toF. tularensis. Our results identify both an alternative pathway for inducible PGE2synthesis and a role for lipid-modifying enzymes in the regulation of macrophage inflammatory function.
Deep Sequencing Analysis Reveals Temporal Microbiota Changes Associated with Development of Bovine Digital Dermatitis
Authors: Krull Adam C. , Shearer Jan K. , Gorden Patrick J. , Cooper Vickie L. , Phillips Gregory J. , Plummer Paul J.
Published: May 2014

Bovine digital dermatitis (DD) is a leading cause of lameness in dairy cattle throughout the world. Despite 35 years of research, the definitive etiologic agent associated with the disease process is still unknown. Previous studies have demonstrated that multiple bacterial species are associated with lesions, with spirochetes being the most reliably identified organism. This study details the deep sequencing-based metagenomic evaluation of 48 staged DD biopsy specimens collected during a 3-year longitudinal study of disease progression. Over 175 million sequences were evaluated by utilizing both shotgun and 16S metagenomic techniques. Based on the shotgun sequencing results, there was no evidence of a fungal or DNA viral etiology. The bacterial microbiota of biopsy specimens progresses through a systematic series of changes that correlate with the novel morphological lesion scoring system developed as part of this project. This scoring system was validated, as the microbiota of each stage was statistically significantly different from those of other stages (
P
< 0.001). The microbiota of control biopsy specimens were the most diverse and became less diverse as lesions developed. Although
Treponema
spp. predominated in the advanced lesions, they were in relatively low abundance in the newly described early lesions that are associated with the initiation of the disease process. The consortium of
Treponema
spp. identified at the onset of disease changes considerably as the lesions progress through the morphological stages identified. The results of this study support the hypothesis that DD is a polybacterial disease process and provide unique insights into the temporal changes in bacterial populations throughout lesion development.
Virus-Encoded MicroRNAs Facilitate Gammaherpesvirus Latency and PathogenesisIn Vivo
Authors: Feldman Emily R. , Kara Mehmet , Coleman Carrie B. , Grau Katrina R. , Oko Lauren M. , Krueger Brian J. , Renne Rolf , van Dyk Linda F. , Tibbetts Scott A.
Published: May 2014

Gammaherpesviruses, including Epstein-Barr virus (EBV), Kaposi sarcoma-associated herpesvirus (KSHV, or HHV-8), and murine gammaherpesvirus 68 (MHV68, γHV68, or MuHV-4), are B cell-tropic pathogens that each encode at least 12 microRNAs (miRNAs). It is predicted that these regulatory RNAs facilitate infection by suppressing host target genes involved in a wide range of key cellular pathways. However, the precise contribution that gammaherpesvirus miRNAs make to viral life cycle and pathogenesisin vivois unknown. MHV68 infection of mice provides a highly useful system to dissect the function of specific viral elements in the context of both asymptomatic infection and disease. Here, we report (i) analysis ofin vitroandin vivoMHV68 miRNA expression, (ii) generation of an MHV68 miRNA mutant with reduced expression of all 14 pre-miRNA stem-loops, and (iii) comprehensive phenotypic characterization of the miRNA mutant virusin vivo. The profile of MHV68 miRNAs detected in infected cell lines varied with cell type and did not fully recapitulate the profile from cells latently infectedin vivo. The miRNA mutant virus, MHV68.Zt6, underwent normal lytic replicationin vitroandin vivo, demonstrating that the MHV68 miRNAs are dispensable for acute replication. During chronic infection, MHV68.Zt6 was attenuated for latency establishment, including a specific defect in memory B cells. Finally, MHV68.Zt6 displayed a striking attenuation in the development of lethal pneumonia in mice deficient in IFN-γ. These data indicate that the MHV68 miRNAs may facilitate virus-driven maturation of infected B cells and implicate the miRNAs as a critical determinant of gammaherpesvirus-associated disease.

IMPORTANCEGammaherpesviruses such as EBV and KSHV are widespread pathogens that establish lifelong infections and are associated with the development of numerous types of diseases, including cancer. Gammaherpesviruses encode many small noncoding RNAs called microRNAs (miRNAs). It is predicted that gammaherpesvirus miRNAs facilitate infection and disease by suppressing host target transcripts involved in a wide range of key cellular pathways; however, the precise contribution that these regulatory RNAs make toin vivovirus infection and pathogenesis is unknown. Here, we generated a mutated form of murine gammaherpesvirus (MHV68) to dissect the function of gammaherpesvirus miRNAsin vivo. We demonstrate that the MHV68 miRNAs were dispensable for short-term virus replication but were important for establishment of lifelong infection in the key virus reservoir of memory B cells. Moreover, the MHV68 miRNAs were essential for the development of virus-associated pneumonia, implicating them as a critical component of gammaherpesvirus-associated disease.
Peptidoglycan Synthesis Machinery in Agrobacterium tumefaciens During Unipolar Growth and Cell Division
Authors: Cameron Todd A. , Anderson-Furgeson James , Zupan John R. , Zik Justin J. , Zambryski Patricia C.
Published: May 2014

The synthesis of peptidoglycan (PG) in bacteria is a crucial process controlling cell shape and vitality. In contrast to bacteria such as
Escherichia coli
that grow by dispersed lateral insertion of PG, little is known of the processes that direct polar PG synthesis in other bacteria such as the
Rhizobiales
. To better understand polar growth in the
Rhizobiales
Agrobacterium tumefaciens
, we first surveyed its genome to identify homologs of (~70) well-known PG synthesis components. Since most of the canonical cell elongation components are absent from
A. tumefaciens
, we made fluorescent protein fusions to other putative PG synthesis components to assay their subcellular localization patterns. The cell division scaffolds FtsZ and FtsA, PBP1a, and a
Rhizobiales
- and
Rhodobacterales
-specific
l
,
d
-transpeptidase (LDT) all associate with the elongating cell pole. All four proteins also localize to the septum during cell division. Examination of the dimensions of growing cells revealed that new cell compartments gradually increase in width as they grow in length. This increase in cell width is coincident with an expanded region of LDT-mediated PG synthesis activity, as measured directly through incorporation of exogenous
d
-amino acids. Thus, unipolar growth in the
Rhizobiales
is surprisingly dynamic and represents a significant departure from the canonical growth mechanism of
E. coli
and other well-studied bacilli.

IMPORTANCE
Many rod-shaped bacteria, including pathogens such as
Brucella
and
Mycobacteriu
, grow by adding new material to their cell poles, and yet the proteins and mechanisms contributing to this process are not yet well defined. The polarly growing plant pathogen
Agrobacterium tumefaciens
was used as a model bacterium to explore these polar growth mechanisms. The results obtained indicate that polar growth in this organism is facilitated by repurposed cell division components and an otherwise obscure class of alternative peptidoglycan transpeptidases (
l
,
d
-transpeptidases). This growth results in dynamically changing cell widths as the poles expand to maturity and contrasts with the tightly regulated cell widths characteristic of canonical rod-shaped growth. Furthermore, the abundance and/or activity of
l
,
d
-transpeptidases appears to associate with polar growth strategies, suggesting that these enzymes may serve as attractive targets for specifically inhibiting growth of
Rhizobiales
,
Actinomycetales
, and other polarly growing bacterial pathogens.
A case of left main coronary artery embolus further embolising to the left anterior descending artery
Authors: Giri Smith , Hwang Inyong , Alsafwah Shadwan
Published: May 2014

Coronary embolism is an uncommon cause of myocardial infarction. The usual source of a coronary embolus is an intracardiac thrombus or vegetation. Embolisation to the left main coronary artery is an extremely rare event and is usually fatal. We present a case of a 38-year-old woman with embolisation to the left main coronary artery which further embolised distally to the left anterior descending artery leading to a non-ST elevation myocardial infarction. The non-occlusive nature of the left main coronary artery embolus might have led to a favourable prognosis in our patient.
Giant adrenal myelolipoma: when trauma and oncology collide
Authors: Zorgdrager Marcel , Pol Robert , van Hemel Bettien , van Ginkel Robert
Published: May 2014

Three patients presented some decades after severe traumatic injury with atypical bowel symptoms which were caused by a giant myelolipoma of the adrenal gland. The aetiology of this rare, benign and generally asymptomatic tumour is virtually unknown at present and several hypotheses have been devised. This report describes a possible association between high-energy trauma and the development of giant myelolipomas, further contributing to the hypothesis that severe systemic stress could be an aetiological factor in the development of an adrenal myelolipoma.
Prolonged, but transient, elevation of liver and biliary function tests in a healthy infant affected with breast milk jaundice
Authors: Poddighe Dimitri , Castelli Lucia , Marseglia Gian Luigi , Bruni Paola
Published: May 2014

Unconjugated hyperbilirubinaemia is a common finding in newborns. When it is exaggerated, it is usually investigated in order to exclude several diseases, such as newborn's haemolytic diseases, infections or hypothyroidism. Breast milk jaundice is a form of neonatal jaundice related to breast feeding and it is not usually associated with any clinical issue and/or other laboratory abnormalities. We describe a case of breast milk jaundice being associated, unexpectedly, to significant elevation of plasmatic liver and biliary enzymes. Despite the infant's good clinical condition and growth, several investigations were performed and these ruled out metabolic, infectious and autoimmune liver diseases. All liver function tests normalised by 6–7 months of life. We suggest that the finding of hypertransaminasaemia and hyper-γ-glutamyl transpeptidase in a benign clinical context (similar to what we described) should be followed for 6–7 months before performing sophisticated and expensive diagnostic investigations which aim at excluding some unlikely and severe diseases in a completely asymptomatic infant.
Actinomycesinfection causing acute right iliac fossa pain
Authors: Govindarajah Narendranath , Hameed Waseem , Middleton Simon , Booth Michael
Published: May 2014

This is a case of a 75-year-old man being admitted to the on-call surgical department with acute abdominal pain. On arrival he was clinically dehydrated and shocked with localised pain over McBurney's point and examination findings were suggestive of appendiceal or other colonic pathology. Full blood testing revealed a white cell count of 38×109/L and a C reactive protein (CRP) of 278 mg/L. A CT scan revealed a gallbladder empyema that extended into the right iliac fossa. This case highlights the potential for a hyperdistended gallbladder empyema to present as acute right iliac fossa pain with blood tests suggestive of complicated disease. Further analysis confirmedActinomycesinfection as the underlying aetiology prior to a laparoscopic subtotal cholecystectomy. This case serves to remind clinicians of this as a rare potential cause of atypical gallbladder pathology.
A novel role of transient receptor potential mucolipin1 (TRPML1) in protecting against imidazole-induced cytotoxicity
Authors: Liu Zhenxing , Zhao Shuan , Wu Shuaishuai , Zhang Jingyou , Nie Zunyang , Zeng Shenming
Published: May 2014

Lysosomotropic amines cause serious side effects such as cytoplasmic vacuolation and cell death. TRPML1 (also known as mucolipin1), a member of the transient receptor potential (TRP) protein family, may regulate fusion/fission of vesicles along the endocytic pathway and some aspects of lysosomal ion homeostasis. Nevertheless, it is still unknown whether TRPML1 is involved in death of mammalian cells induced by lysosomotropic agents. In this study, imidazole was used as a model to investigate the role of TRPML1 in the cytotoxicity of lysosomotropic agents. Overexpression of wild-type TRPML1 inhibited imidazole-induced vacuole formation and cell death in human endometrial adenocarcinoma (HEC-1B) cells. In contrast, siRNA-mediated TRPML1 knockdown increased the cell death induced by imidazole. Bafilomycin A1 raises the pH of acidic organelles and therefore suppresses accumulation of weak bases in them. Similarly, lysosomal pH was raised in TRPML1-overexpressing cells; therefore, we inferred that TRPML1 protected against imidazole toxicity by regulating the pH of acidic organelles. We concluded that TRPML1 had a novel role in protecting against lysosomotropic amine toxicity.
Counting test facility for the Borexino experiment
Authors: Ranucci G. , Meroni E.
Published: May 2014

A fundamental breakthrough which opened the way to the realization of the Borexino detector was the demonstration of exceptionally low, unprecedented radioactive contaminations in the liquid scintillator, obtained with its pilot prototype Counting Test Facility. Though of limited dimension, with its 4.8 m3 of active liquid core, CTF has however been a key milestone not only for Borexino, but also for the entire field of the ultra-low background searches. Here, we succinctly remind the motivations, which concurred to lay down the project, as well as the specific radiopurity challenge, which guided the design. After the description of the technical elements of the detector, the main outcomes are summarized, both regarding optical and purity scintillator properties, with special emphasis on the exceptional achievements in term of ultra-low traces of radioactive contaminants. The discussion is completed with the description of how CTF was employed for the pre-qualification of the entire inventory of the Borexino scintillator, confirming also in the final phase of its life its essential role for the success of the overall Borexino solar neutrino program.
CP mixed property of the Higgs-like particle in the decay channel h→Z Z*→4l
Authors: Sun Yi , Wang Xian-Fu , Gao Dao-Neng
Published: May 2014

Current experiments do not support, as ATLAS and CMS Collaborations at the Large Hadron Collider reported, that the Higgs-like resonance discovered in July 2012 is a pure CP-odd state. We examine a general hZZ vertex which contains CP-even and CP-odd couplings, by studying the process [Formula: see text] with l1, l2 = e or μ, to explore the CP mixed property of the Higgs-like particle. One momentum asymmetry and two angular asymmetries have been analyzed in order to reveal the difference from different CP-couplings. Our study shows that these asymmetries could be interesting observables in the future precise experiments.
The preon sector of the SLq(2) model and the binding problem
Authors: Finkelstein Robert J.
Published: May 2014

There are suggestive experimental indications that the leptons, neutrinos, and quarks might be composite and that their structure is described by the quantum group SLq(2). Since the hypothetical preons must be very heavy relative to the masses of the leptons, neutrinos, and quarks, there must be a very strong binding field to permit these composite particles to form. Unfortunately there are no experiments direct enough to establish the order of magnitude needed to make the SLq(2) Lagrangian dynamics quantitative. It is possible, however, to parametrize the preon masses and interactions that would be necessary to stabilize the three particle composite representing the leptons, neutrinos, and quarks. In this note we examine possible parametrizations of the masses and the interactions of these hypothetical structures. We also note an alternative view of SLq(2) preons.
Cellular Memristive Dynamical Systems (CMDS)
Authors: Bavandpour Mohammad , Soleimani Hamid , Bagheri-Shouraki Saeed , Ahmadi Arash , Abbott Derek , Chua Leon O.
Published: May 2014

This study presents a cellular-based mapping for a special class of dynamical systems for embedding neuron models, by exploiting an efficient memristor crossbar-based circuit for its implementation. The resultant reconfigurable memristive dynamical circuit exhibits various bifurcation phenomena, and responses that are characteristic of dynamical systems. High programmability of the circuit enables it to be applied to real-time applications, learning systems, and analytically indescribable dynamical systems. Moreover, its efficient implementation platform makes it an appropriate choice for on-chip applications and prostheses. We apply this method to the Izhikevich, and FitzHugh–Nagumo neuron models as case studies, and investigate the dynamical behaviors of these circuits.
Zwanzig's Trajectories Used in Relation to Thermodynamical Chaos for Spin Wave Description
Authors: Ławrynowicz Julian , Wojtczak Leszek , Niemczynowicz Agnieszka
Published: May 2014

The paper shows the use of Zwanzig's trajectories for spin wave description. The main idea consists in the application of Zwanzig's method to the description of the temporal derivative of magnetization in the direction of rf field in terms of Zwanzig's resolvents found for the magnetization components considered in the harmonic approximation. In particular, the spin waves resonance description can be tested. It reflects well the thermodynamical chaos as described in a fractal approach of the first author (2012, paper joint with Nowak-Kȩpczyk and Suzuki).
Deciphering Dynamics of Epidemic Spread: The Case of Influenza Virus
Authors: Upadhyay Ranjit Kumar , Roy Parimita , Rai Vikas
Published: May 2014

In this paper, we have proposed and analyzed a simple model of Influenza spread with an asymptotic transmission rate. Existence and uniqueness of solutions are established and shown to be uniformly bounded for all non-negative initial values. We have also found a sufficient condition which ensures the persistence of the model system. This implies that both susceptible and infected will always coexist at any location of the inhabited domain. This coexistence is independent of values of the diffusivity constants for two subpopulations. The global stability of the endemic equilibrium is established by constructing a Lyapunov function. By linearizing the system at the positive constant steady-state solution and analyzing the associated characteristic equation, conditions for Hopf and Turing bifurcations are obtained. We have also studied the criteria for diffusion-driven instability caused by local random movements of both susceptible and infective subpopulations. Turing patterns selected by the reaction–diffusion system under zero flux boundary conditions have been explored.

Numerical simulations show that contact rate, β which is related to the reproduction number [Formula: see text], plays an important role in spatial pattern formation. It was found that diffusion has appreciable influence on spatial spread of epidemics. The wave of chaos appears to be a dominant mode of disease dispersal. This suggests a bidirectional spread for influenza epidemics. The epidemic propagates in the form of nonchaotic and chaotic waves as observed in H1N1 incidence data of positive tests in 2009 in the United States. We have conducted numerical simulations to confirm the analytic work and observed interesting behaviors. This suggests that influenza has a complex dynamics of spatial spread which evolves with time.
On the Limit Cycles of the Polynomial Differential Systems with a Linear Node and Homogeneous Nonlinearities
Authors: Llibre Jaume , Yu Jiang , Zhang Xiang
Published: May 2014

We consider the class of polynomial differential equations ẋ = λx + Pn(x, y), ẏ = μy + Qn(x, y) in ℝ2 where Pn(x, y) and Qn(x, y) are homogeneous polynomials of degree n > 1 and λ ≠ μ, i.e. the class of polynomial differential systems with a linear node with different eigenvalues and homogeneous nonlinearities. For this class of polynomial differential equations, we study the existence and nonexistence of limit cycles surrounding the node localized at the origin of coordinates.
Analysis of Bifurcation Behavior of a Piecewise Linear Vibrator with Electromagnetic Coupling for Energy Harvesting Applications
Authors: El Aroudi A. , Ouakad H. , Benadero L. , Younis M.
Published: May 2014

Recently, nonlinearities have been shown to play an important role in increasing the extracted energy of vibration-based energy harvesting systems. In this paper, we study the dynamical behavior of a piecewise linear (PWL) spring-mass-damper system for vibration-based energy harvesting applications. First, we present a continuous time single degree of freedom PWL dynamical model of the system. Different configurations of the PWL model and their corresponding state-space regions are derived. Then, from this PWL model, extensive numerical simulations are carried out by computing time-domain waveforms, state-space trajectories and frequency responses under a deterministic harmonic excitation for different sets of system parameter values. Stability analysis is performed using Floquet theory combined with Filippov method, Poincaré map modeling and finite difference method (FDM). The Floquet multipliers are calculated using these three approaches and a good concordance is obtained among them. The performance of the system in terms of the harvested energy is studied by considering both purely harmonic excitation and a noisy vibrational source. A frequency-domain analysis shows that the harvested energy could be larger at low frequencies as compared to an equivalent linear system, in particular, for relatively low excitation intensities. This could be an advantage for potential use of this system in low frequency ambient vibrational-based energy harvesting applications.
Electromagnetic Analog of 3D Autonomous ODEs with Quadratic Nonlinearities
Authors: Botha A. E.
Published: May 2014

It is shown that the general class of three-dimensional first-order ordinary differential equations with quadratic nonlinearities can be physically interpreted as the dynamics of a charged particle in an electromagnetic field, with a constant gradient B-field. The general class of equations is derived within the Lagrangian formalism of classical mechanics. As an application of this interpretation a new way of experimentally realizing the Lorenz chaotic attractors is proposed. The actual construction of such systems could be facilitated by existing magnetic resonance imaging technology, which already makes use of constant gradient fields, and may find applications in areas such as nuclear medicine and magnetic confinement fusion devices.
Chaotic Oscillations of Solutions of First Order Hyperbolic Systems in 1D with Nonlinear Boundary Conditions
Authors: Dai Xiongping , Huang Tingwen , Huang Yu , Chen Goong
Published: May 2014

We study chaotic oscillations of solutions of a first order hyperbolic system in one-dimensional space, where the governing equation is linear but the boundary condition contains nonlinearity with nonlocal and possibly time-delay effects. The main thrust of the paper is the advancement of existing chaos theory to multicomponent hyperbolic PDEs that allows a unified treatment of a general class of nonlinear, nonlocal and time-delayed boundary conditions where components of waves travel with several different speeds.
Spectral Boundary Adaptation on Heart Rate Variability for Sleep and Wake Classification
Authors: Long Xi , Fonseca Pedro , Haakma Reinder , Aarts Ronald M. , Foussier Jerome
Published: May 2014

A method of adapting the boundaries when extracting the spectral features from heart rate variability (HRV) for sleep and wake classification is described. HRV series can be derived from electrocardiogram (ECG) signals obtained from single-night polysomnography (PSG) recordings. Conventionally, the HRV spectral features are extracted from the spectrum of an HRV series with fixed boundaries specifying bands of very low frequency (VLF), low frequency (LF), and high frequency (HF). However, because they are fixed, they may fail to accurately reflect certain aspects of autonomic nervous activity which in turn may limit their discriminative power, e.g. in sleep and wake classification. This is in part related to the fact that the sympathetic tone (partially reflected in the LF band) and the respiratory activity (modulated in the HF band) vary over time. In order to minimize the impact of these variations, we adapt the HRV spectral boundaries using time-frequency analysis. Experiments were conducted on a data set acquired from two groups with 15 healthy and 15 insomnia subjects each. Results show that adapting the HRV spectral features significantly increased their discriminative power when classifying sleep and wake. Additionally, this method also provided a significant improvement of the overall classification performance when used in combination with other HRV non-spectral features. Furthermore, compared with the use of actigraphy, the classification performed better when combining it with the HRV features.