Search tips
Search criteria

Results 1-25 (37)

Clipboard (0)

Select a Filter Below

Year of Publication
more »
2.  Overview of the functional virulent genome of the coffee leaf rust pathogen Hemileia vastatrix with an emphasis on early stages of infection 
Hemileia vastatrix is the causal agent of coffee leaf rust, the most important disease of coffee Arabica. In this work, a 454-pyrosequencing transcriptome analysis of H. vastatrix germinating urediniospores (gU) and appressoria (Ap) was performed and compared to previously published in planta haustoria-rich (H) data. A total of 9234 transcripts were identified and annotated. Ca. 50% of these transcripts showed no significant homology to international databases. Only 784 sequences were shared by the three conditions, and 75% were exclusive of either gU (2146), Ap (1479) or H (3270). Relative transcript abundance and RT-qPCR analyses for a selection of genes indicated a particularly active metabolism, translational activity and production of new structures in the appressoria and intense signaling, transport, secretory activity and cellular multiplication in the germinating urediniospores, suggesting the onset of a plant-fungus dialogue as early as at the germ tube stage. Gene expression related to the production of carbohydrate-active enzymes and accumulation of glycerol in germinating urediniospores and appressoria suggests that combined lytic and physical mechanisms are involved in appressoria-mediated penetration. Besides contributing to the characterization of molecular processes leading to appressoria-mediated infection by rust fungi, these results point toward the identification of new H. vastatrix candidate virulence factors, with 516 genes predicted to encode secreted proteins.
PMCID: PMC3953675  PMID: 24672531
appressorium; coffee leaf rust; germinating urediniospore; haustorium; pyrosequencing; transcriptome
3.  Genome analysis of poplar LRR-RLP gene clusters reveals RISP, a defense-related gene coding a candidate endogenous peptide elicitor 
In plants, cell-surface receptors control immunity and development through the recognition of extracellular ligands. Leucine-rich repeat receptor-like proteins (LRR-RLPs) constitute a large multigene family of cell-surface receptors. Although this family has been intensively studied, a limited number of ligands has been identified so far, mostly because methods used for their identification and characterization are complex and fastidious. In this study, we combined genome and transcriptome analyses to describe the LRR-RLP gene family in the model tree poplar (Populus trichocarpa). In total, 82 LRR-RLP genes have been identified in P. trichocarpa genome, among which 66 are organized in clusters of up to seven members. In these clusters, LRR-RLP genes are interspersed by orphan, poplar-specific genes encoding small proteins of unknown function (SPUFs). In particular, the nine largest clusters of LRR-RLP genes (47 LRR-RLPs) include 71 SPUF genes that account for 59% of the non-LRR-RLP gene content within these clusters. Forty-four LRR-RLP and 55 SPUF genes are expressed in poplar leaves, mostly at low levels, except for members of some clusters that show higher and sometimes coordinated expression levels. Notably, wounding of poplar leaves strongly induced the expression of a defense SPUF gene named Rust-Induced Secreted protein (RISP) that has been previously reported as a marker of poplar defense responses. Interestingly, we show that the RISP-associated LRR-RLP gene is highly expressed in poplar leaves and slightly induced by wounding. Both gene promoters share a highly conserved region of ~300 nucleotides. This led us to hypothesize that the corresponding pair of proteins could be involved in poplar immunity, possibly as a ligand/receptor couple. In conclusion, we speculate that some poplar SPUFs, such as RISP, represent candidate endogenous peptide ligands of the associated LRR-RLPs and we discuss how to investigate further this hypothesis.
PMCID: PMC3975113  PMID: 24734035
gene clustering; immunity; ligands; receptors; poplar; wounding
4.  A SYBR Green 1-based in vitro test of susceptibility of Ghanaian Plasmodium falciparum clinical isolates to a panel of anti-malarial drugs 
Malaria Journal  2013;12:450.
Based on report of declining efficacy of chloroquine, Ghana shifted to the use of artemisinin-based combination therapy (ACT) in 2005 as the first-line anti-malarial drug. Since then, there has not been any major evaluation of the efficacy of anti-malarial drugs in Ghana in vitro. The sensitivity of Ghanaian Plasmodium falciparum isolates to anti-malarial drugs was, therefore, assessed and the data compared with that obtained prior to the change in the malaria treatment policy.
A SYBR Green 1 fluorescent-based in vitro drug sensitivity assay was used to assess the susceptibility of clinical isolates of P. falciparum to a panel of 12 anti-malarial drugs in three distinct eco-epidemiological zones in Ghana. The isolates were obtained from children visiting health facilities in sentinel sites located in Hohoe, Navrongo and Cape Coast municipalities. The concentration of anti-malarial drug inhibiting parasite growth by 50% (IC50) for each drug was estimated using the online program, ICEstimator.
Pooled results from all the sentinel sites indicated geometric mean IC50 values of 1.60, 3.80, 4.00, 4.56, 5.20, 6.11, 10.12, 28.32, 31.56, 93.60, 107.20, and 8952.50 nM for atovaquone, artesunate, dihydroartemisin, artemether, lumefantrine, amodiaquine, mefloquine, piperaquine, chloroquine, tafenoquine, quinine, and doxycycline, respectively. With reference to the literature threshold value indicative of resistance, the parasites showed resistance to all the test drugs except the artemisinin derivatives, atovaquone and to a lesser extent, lumefantrine. There was nearly a two-fold decrease in the IC50 value determined for chloroquine in this study compared to that determined in 2004 (57.56 nM). This observation is important, since it suggests a significant improvement in the efficacy of chloroquine, probably as a direct consequence of reduced drug pressure after cessation of its use. Compared to that measured prior to the change in treatment policy, significant elevation of artesunate IC50 value was observed. The results also suggest the existence of possible cross-resistance among some of the test drugs.
Ghanaian P. falciparum isolates, to some extent, have become susceptible to chloroquine in vitro, however the increasing trend in artesunate IC50 value observed should be of concern. Continuous monitoring of ACT in Ghana is recommended.
PMCID: PMC3878558  PMID: 24341604
Isolates; in vitro; Susceptibility; Inhibition; Plasmodium falciparum
5.  Increased pfmdr1 gene copy number and the decline in pfcrt and pfmdr1 resistance alleles in Ghanaian Plasmodium falciparum isolates after the change of anti-malarial drug treatment policy 
Malaria Journal  2013;12:377.
With the introduction of artemisinin-based combination therapy (ACT) in 2005, monitoring of anti-malarial drug efficacy, which includes the use of molecular tools to detect known genetic markers of parasite resistance, is important for first-hand information on the changes in parasite susceptibility to drugs in Ghana. This study investigated the Plasmodium falciparum multidrug resistance gene (pfmdr1) copy number, mutations and the chloroquine resistance transporter gene (pfcrt) mutations in Ghanaian isolates collected in seven years to detect the trends in prevalence of mutations.
Archived filter paper blood blots collected from children aged below five years with uncomplicated malaria in 2003–2010 at sentinel sites were used. Using quantitative real-time polymerase chain reaction (qRT-PCR), 756 samples were assessed for pfmdr1 gene copy number. PCR and restriction fragment length polymorphism (RFLP) were used to detect alleles of pfmdr1 86 in 1,102 samples, pfmdr1 184, 1034, 1042 and 1246 in 832 samples and pfcrt 76 in 1,063 samples. Merozoite surface protein 2 (msp2) genotyping was done to select monoclonal infections for copy number analysis.
The percentage of isolates with increased pfmdr1 copy number were 4, 27, 9, and 18% for 2003–04, 2005–06, 2007–08 and 2010, respectively. Significant increasing trends for prevalence of pfmdr1 N86 (×2 = 96.31, p <0.001) and pfcrt K76 (×2 = 64.50, p <0.001) and decreasing trends in pfmdr1 Y86 (×2 = 38.52, p <0.001) and pfcrt T76 (×2 = 43.49, p <0.001) were observed from 2003–2010. The pfmdr1 F184 and Y184 prevalence showed an increasing and decreasing trends respectively but were not significant (×2 = 7.39,p=0.060; ×2 = 7.49, p = 0.057 respectively). The pfmdr1 N86-F184-D1246 haplotype, which is alleged to be selected by artemether-lumefantrine showed a significant increasing trend (×2 = 20.75, p < 0.001).
Increased pfmdr1 gene copy number was observed in the isolates analysed and this finding has implications for the use of ACT in the country although no resistance has been reported. The decreasing trend in the prevalence of chloroquine resistance markers after change of treatment policy presents the possibility for future introduction of chloroquine as prophylaxis for malaria risk groups such as children and pregnant women in Ghana.
PMCID: PMC3819684  PMID: 24172030
Anti-malarial drug resistance; Plasmodium falciparum chloroquine resistance transporter gene (pfcrt); Plasmodium falciparum multidrug resistance gene (pfmdr1); Molecular markers; Ghana
6.  Optimization and validation of a reversed-phase high performance liquid chromatography method for the measurement of bovine liver methylmalonyl-coenzyme a mutase activity 
BMC Biochemistry  2013;14:25.
Methylmalonyl-CoA mutase (MCM) is an adenosylcobalamin-dependent enzyme that catalyses the interconversion of (2R)-methylmalonyl-CoA to succinyl-CoA. In humans, a deficit in activity of MCM, due to an impairment of intracellular formation of adenosylcobalamin and methylcobalamin results in a wide spectrum of clinical manifestations ranging from moderate to fatal. Consequently, MCM is the subject of abundant literature. However, there is a lack of consensus on the reliable method to monitor its activity. This metabolic pathway is highly solicited in ruminants because it is essential for the utilization of propionate formed during ruminal fermentation. In lactating dairy cows, propionate is the major substrate for glucose formation. In present study, a reversed-phase high performance liquid chromatography (RP-HPLC) was optimized and validated to evaluate MCM activity in bovine liver. The major aim of the study was to describe the conditions to optimize reproducibility of the method and to determine stability of the enzyme and its product during storage and processing of samples.
Specificity of the method was good, as there was no interfering peak from liver extract at the retention times corresponding to methylmalonyl-CoA or succinyl-CoA. Repeatability of the method was improved as compared to previous RP-HPLC published data. Using 66 μg of protein, intra-assay coefficient of variation (CV) of specific activities, ranged from 0.90 to 8.05% and the CV inter-day was 7.40%. Storage and processing conditions (frozen homogenate of fresh tissue vs. fresh homogenate of tissue snapped in liquid nitrogen) did not alter the enzyme activity. The analyte was also stable in liver crude extract for three frozen/thawed cycles when stored at -20°C and thawed to room temperature.
The improved method provides a way for studying the effects of stages of lactation, diet composition, and physiology in cattle on MCM activity over long periods of time, such as a complete lactation period. Interestingly, this sensitive and accurate method could benefit the study of the cobalamin status in experimental studies and clinical cases.
PMCID: PMC3856599  PMID: 24131771
Methylmalonyl-CoA mutase; Liver; Cattle; Dairy cow; Succinyl-CoA; RP-HPLC
7.  Impaired Mouse Mammary Gland Growth and Development is Mediated by Melatonin and its MT1 G Protein-Coupled Receptor via Repression of ERα, Akt1, and Stat5 
Journal of pineal research  2012;53(3):307-318.
To determine if melatonin, via its MT1 G protein-coupled receptor (GPCR), impacts mouse mammary gland development, we generated a mouse mammary tumor virus (MMTV)-MT1-Flag-mammary gland over-expressing (MT1-mOE) transgenic mouse. Increased expression of the MT1-Flag transgene was observed in the mammary glands of pubescent MT1-mOE transgenic female mice, with further significant increases during pregnancy and lactation. Mammary gland whole mounts from MT1-mOE mice showed significant reductions in ductal growth, ductal branching, and terminal end bud (TEB) formation. Elevated MT1 receptor expression in pregnant and lactating female MT1-mOE mice was associated with reduced lobulo-alveolar development, inhibition of mammary epithelial cell proliferation, and significant reductions in body weights of suckling pups. Elevated MT1 expression in pregnant and lactating MT1-mOE mice correlated with reduced mammary gland expression of Akt1, phospho-Stat5, Wnt4, estrogen receptor alpha (ERα), progesterone receptors (PR) A and B, and milk proteins β-casein and whey acidic protein (WAP). Estrogen and progesterone stimulated mammary gland development was repressed by elevated MT1 receptor expression and exogenous melatonin administration. These studies demonstrate that the MT1 melatonin receptor and its ligand melatonin play an important regulatory role in mammary gland development and lactation in mice through both growth suppression and alteration of developmental paradigms.
PMCID: PMC3422609  PMID: 22582905
Melatonin; MT1 Receptor; AKT; Stat5; Mammary Gland Development
8.  Strengthening Families of Children with Developmental Concerns: Parent Perceptions of Developmental Screening and Services in Head Start 
Ethnicity & disease  2011;21(3 0 1):S1-89-93.
The authors investigated perceptions of parents with children in the Head Start program about the processes of detection and intervention for developmental concerns.
Descriptive, qualitative study.
A large, urban Head Start agency, operating 14 centers and annually serving more than 1200 predominantly Latino children. During 2008–2009, a collaborative partnership with academicians from UCLA was created to evaluate their model of developmental screening and referrals.
Participants and Procedures
We conducted 5 focus groups with a total of 30 parents of Head Start children with developmental concerns. Parents were asked about where they go for information when they have concerns, how they perceived the developmental screening process and services, and how children and families have changed after being in the Head Start program. Focus groups were recorded, transcribed and translated into English, then coded in ATLAS. ti using the domains above and sorted into themes for analysis.
Parents perceived the screening process as both diagnostically and therapeutically important, with multiple benefits ranging from closer parent-teacher relationships to improved parenting and understanding of developmental interventions. Families focused their discussion on the importance of social-emotional and behavioral development, with school readiness and improved expressive language as important but secondary outcomes.
For families of children with developmental and behavioral risks or concerns, a structured developmental screening process in a preschool setting, such as that provided by Head Start, may serve as a vital gateway for identifying and addressing concerns and promoting social-emotional learning, parent engagement, language development and school readiness.
PMCID: PMC3715307  PMID: 22352085
Early Childhood Development; Developmental Screening; Early Intervention; Head Start Program; Preschool; Latino Families; Social-Emotional Development
9.  Magnetic resonance volumetric assessments of brains in fetuses with ventriculomegaly correlated to outcome 
To correlate MR 2D measurements of lateral ventricular width and 3D measures of lateral ventricular and supratentorial parenchymal volumes to postnatal outcomes in fetuses with ventriculomegaly (VM).
307 fetuses (mean gestational age 26.0 weeks, range 15.7-39.4 weeks) had MR volumetry after referral for VM. Fetuses were grouped into those with (N=114) or without (N=193) other CNS anomalies. Pregnancy outcome and postnatal neurodevelopmental outcomes up to age 3 were obtained. A subgroup analysis was performed excluding fetuses with other CNS anomalies. Logistic regression analysis was performed to assess which measure was most predictive of outcome.
There were 50 terminations and 2 stillbirths. There were 255 live births. 75 were lost to follow-up. Among 180 liveborn infants with follow-up, 140 had an abnormal and 40 had normal outcome. Atrial diameter (p<0.0001), frontal horn diameter (p<0.0001), and ventricular volume (p=0.04) were each predictive of live-birth, with each having 92% specificity at 60% sensitivity. Among fetuses without other CNS anomalies, 180/193 (93%) pregnancies resulted in live deliveries, with atrial diameter (p<0.0001), frontal horn diameter (p=0.003), and ventricular volume (p=0.008) associated with live birth, and with atrial diameter having highest specificity of >99% at 60% sensitivity. Parenchymal volume was not associated with normal or abnormal outcome (either livebirth vs. demise or normal vs. abnormal neurodevelopmental outcome). Among live-borns, there was no age-adjusted threshold for any of the measures that reliably distinguished between normal and abnormal neurodevelopmental outcome.
Ventricular volume and diameter, but not parenchymal volume, correlate with live birth in fetuses with VM. However, once live-born, neither 2D nor 3D measurements can distinguish a fetus that will go on to have a normal outcome.
PMCID: PMC3683412  PMID: 21527607
central nervous system; fetus; MRI; ventriculomegaly; volumetry; neurodevelopment
10.  Dichotomous roles for the orphan nuclear receptor NURR1 in breast cancer 
BMC Cancer  2013;13:139.
NR4A orphan nuclear receptors are involved in multiple biological processes which are important in tumorigenesis such as cell proliferation, apoptosis, differentiation, and glucose utilization. The significance of NR4A family member NURR1 (NR4A2) in breast cancer etiology has not been elucidated. The purpose of this study was to ascertain the impact of NURR1 expression on breast transformation, tumor growth, and breast cancer patient survival.
We determined the expression of NURR1 in normal breast versus breast carcinoma in tissue microarrays (immunohistochemistry), tissue lysates (immunoblot), and at the mRNA level (publically available breast microarrays). In addition NURR1 expression was compared among breast cancer patients in cohorts based on p53 expression, estrogen receptor α expression, tumor grade, and lymph node metastases. Kaplan-Meier survival plots were used to determine the correlation between NURR1 expression and relapse free survival (RFS). Using shRNA-mediated silencing, we determined the effect of NURR1 expression on tumor growth in mouse xenografts.
Results from breast cancer tissue arrays demonstrate a higher NURR1 expression in the normal breast epithelium compared to breast carcinoma cells (p ≤ 0.05). Among cases of breast cancer, NURR1 expression in the primary tumors was inversely correlated with lymph node metastases (p ≤ 0.05) and p53 expression (p ≤ 0.05). Clinical stage and histological grade were not associated with variation in NURR1 expression. In gene microarrays, 4 of 5 datasets showed stronger mean expression of NURR1 in normal breast as compared to transformed breast. Additionally, NURR1 expression was strongly correlated with increase relapse free survival (HR = 0.7) in a cohort of all breast cancer patients, but showed no significant difference in survival when compared among patients whom have not been treated systemically (HR = 0.91). Paradoxically, NURR1 silenced breast xenografts showed significantly decreased growth in comparison to control, underscoring a biphasic role for NURR1 in breast cancer progression.
NURR1 function presents a dichotomy in breast cancer etiology, in which NURR1 expression is associated with normal breast epithelial differentiation and efficacy of systemic cancer therapy, but silencing of which attenuates tumor growth. This provides a strong rationale for the potential implementation of NURR1 as a pharmacologic target and biomarker for therapeutic efficacy in breast cancer.
PMCID: PMC3617898  PMID: 23517088
Breast cancer; NURR1; NR4A2; Orphan receptor
11.  Distinct clinical and pathological characteristics of frontotemporal dementia associated with C9ORF72 mutations 
Brain  2012;135(3):693-708.
The identification of a hexanucleotide repeat expansion in the C9ORF72 gene as the cause of chromosome 9-linked frontotemporal dementia and motor neuron disease offers the opportunity for greater understanding of the relationship between these disorders and other clinical forms of frontotemporal lobar degeneration. In this study, we screened a cohort of 398 patients with frontotemporal dementia, progressive non-fluent aphasia, semantic dementia or mixture of these syndromes for mutations in the C9ORF72 gene. Motor neuron disease was present in 55 patients (14%). We identified 32 patients with C9ORF72 mutations, representing 8% of the cohort. The patients’ clinical phenotype at presentation varied: nine patients had frontotemporal dementia with motor neuron disease, 19 had frontotemporal dementia alone, one had mixed semantic dementia with frontal features and three had progressive non-fluent aphasia. There was, as expected, a significant association between C9ORF72 mutations and presence of motor neuron disease. Nevertheless, 46 patients, including 22 familial, had motor neuron disease but no mutation in C9ORF72. Thirty-eight per cent of the patients with C9ORF72 mutations presented with psychosis, with a further 28% exhibiting paranoid, deluded or irrational thinking, whereas <4% of non-mutation bearers presented similarly. The presence of psychosis dramatically increased the odds that patients carried the mutation. Mutation bearers showed a low incidence of motor stereotypies, and relatively high incidence of complex repetitive behaviours, largely linked to patients’ delusions. They also showed a lower incidence of acquired sweet food preference than patients without C9ORF72 mutations. Post-mortem pathology in five patients revealed transactive response DNA-binding protein 43 pathology, type A in one patient and type B in three. However, one patient had corticobasal degeneration pathology. The findings indicate that C9ORF72 mutations cause some but not all cases of frontotemporal dementia with motor neuron disease. Other mutations remain to be discovered. C9ORF72 mutations are associated with variable clinical presentations and pathology. Nevertheless, the findings highlight a powerful association between C9ORF72 mutations and psychosis and suggest that the behavioural characteristics of patients with C9ORF72 mutations are qualitatively distinct. Mutations in the C9ORF72 gene may be a major cause not only of frontotemporal dementia with motor neuron disease but also of late onset psychosis.
PMCID: PMC3286329  PMID: 22300873
frontotemporal lobar degeneration; clinical characteristics; motor neuron disease; psychosis; neuropathology
12.  Transcriptome analysis of poplar rust telia reveals overwintering adaptation and tightly coordinated karyogamy and meiosis processes 
Most rust fungi have a complex life cycle involving up to five different spore-producing stages. The telial stage that produces melanized overwintering teliospores is one of these and plays a fundamental role for generating genetic diversity as karyogamy and meiosis occur at that stage. Despite the importance of telia for the rust life cycle, almost nothing is known about the fungal genetic programs that are activated in this overwintering structure. In the present study, the transcriptome of telia produced by the poplar rust fungus Melampsora larici-populina has been investigated using whole genome exon oligoarrays and RT-qPCR. Comparative expression profiling at the telial and uredinial stages identifies genes specifically expressed or up-regulated in telia including osmotins/thaumatin-like proteins (TLPs) and aquaporins that may reflect specific adaptation to overwintering as well numerous lytic enzymes acting on plant cell wall, reflecting extensive cell wall remodeling at that stage. The temporal dynamics of karyogamy was followed using combined RT-qPCR and DAPI-staining approaches. This reveals that fusion of nuclei and induction of karyogamy-related genes occur simultaneously between the 25 and 39 days post inoculation time frame. Transcript profiling of conserved meiosis genes indicates a preferential induction right after karyogamy and corroborates that meiosis begins prior to overwintering and is interrupted in Meiosis I (prophase I, diplonema stage) until teliospore germination in early spring.
PMCID: PMC3835972  PMID: 24312107
Melampsora larici-populina; obligate biotrophic fungus; rust lifecycle; teliospores; gene expression; microarray
Journal of pineal research  2011;51(3):259-269.
This review article discusses recent work on the melatonin-mediated circadian regulation and integration of molecular, dietary and metabolic signaling mechanisms involved in human breast cancer growth and the consequences of circadian disruption by exposure to light-at-night (LAN). The antiproliferative effects of the circadian melatonin signal are mediated through a major mechanism involving the activation of MT1 melatonin receptors expressed in human breast cancer cell lines and xenografts. In estrogen receptor (ERα+) human breast cancer cells, melatonin suppresses both ERα mRNA expression and estrogen-induced transcriptional activity of the ERα via MT1-induced activation of Gαi2 signaling and reduction of cAMP levels. Melatonin also regulates the transactivation of additional members of the steroid hormone/nuclear receptor super-family, enzymes involved in estrogen metabolism, expression/activation of telomerase and the expression of core clock and clock-related genes. The anti-invasive/anti-metastatic actions of melatonin involve the blockade of p38 phosphorylation and the expression of matrix metalloproteinases. Melatonin also inhibits the growth of human breast cancer xenografts via another critical pathway involving MT1-mediated suppression of cAMP leading to blockade of linoleic acid (LA) uptake and its metabolism to the mitogenic signaling molecule 13-hydroxyoctadecadienoic acid (13-HODE). Down-regulation of 13-HODE reduces the activation of growth factor pathways supporting cell proliferation and survival. Experimental evidence in rats and humans indicating that LAN-induced circadian disruption of the nocturnal melatonin signal activates human breast cancer growth, metabolism and signaling provides the strongest mechanistic support, thus far, for population and ecological studies demonstrating elevated breast cancer risk in night shift workers and other individuals increasingly exposed to LAN.
PMCID: PMC3162043  PMID: 21605163
Melatonin; Breast Cancer; Diet; Metabolism; Molecular Signaling; Circadian; Disruption
14.  Oscillation of Clock and Clock Controlled Genes Induced by Serum Shock in Human Breast Epithelial and Breast Cancer Cells: Regulation by Melatonin 
This study investigates differences in expression of clock and clock-controlled genes (CCGs) between human breast epithelial and breast cancer cells and breast tumor xenografts in circadian intact rats and examines if the pineal hormone melatonin influences clock gene and CCG expression. Oscillation of clock gene expression was not observed under standard growth conditions in vitro, however, serum shock (50% horse serum for 2 h) induced oscillation of clock gene and CCG expression in MCF-10A cells, which was repressed or disrupted in MCF-7 cells. Melatonin administration following serum shock differentially suppressed or induced clock gene (Bmal1 and Per2) and CCG expression in MCF10A and MCF-7 cells. These studies demonstrate the lack of rhythmic expression of clock genes and CCGs of cells in vitro and that transplantation of breast cancer cells as xenografts into circadian competent hosts re-establishes a circadian rhythm in the peripheral clock genes of tumor cells.
PMCID: PMC3448497  PMID: 23012497
melatonin; clock genes; circadian; serum shock; breast cancer
15.  RNA-Seq of Early-Infected Poplar Leaves by the Rust Pathogen Melampsora larici-populina Uncovers PtSultr3;5, a Fungal-Induced Host Sulfate Transporter 
PLoS ONE  2012;7(8):e44408.
Biotroph pathogens establish intimate interactions with their hosts that are conditioned by the successful secretion of effectors in infected tissues and subsequent manipulation of host physiology. The identification of early-expressed pathogen effectors and early-modulated host functions is currently a major goal to understand the molecular basis of biotrophy. Here, we report the 454-pyrosequencing transcriptome analysis of early stages of poplar leaf colonization by the rust fungus Melampsora larici-populina. Among the 841,301 reads considered for analysis, 616,879 and 649 were successfully mapped to Populus trichocarpa and M. larici-populina genome sequences, respectively. From a methodological aspect, these results indicate that this single approach is not appropriate to saturate poplar transcriptome and to follow transcript accumulation of the pathogen. We identified 19 pathogen transcripts encoding early-expressed small-secreted proteins representing candidate effectors of interest for forthcoming studies. Poplar RNA-Seq data were validated by oligoarrays and quantitatively analysed, which revealed a highly stable transcriptome with a single transcript encoding a sulfate transporter (herein named PtSultr3;5, POPTR_0006s16150) showing a dramatic increase upon colonization by either virulent or avirulent M. larici-populina strains. Perspectives connecting host sulfate transport and biotrophic lifestyle are discussed.
PMCID: PMC3431362  PMID: 22952974
Vaccine  2011;29(17):3183-3191.
Human immunodeficiency virus (HIV)-infected persons are at risk for severe influenza infections. Although vaccination against the H1N1 pandemic influenza strain is recommended, currently, there are no data on the durability of post-vaccination antibody responses in this population.
HIV-infected and HIV-uninfected adults (18–50 years old) received a single dose of monovalent 2009 influenza A (H1N1) vaccine (strain A/California/7/2009H1N1). Antibody levels to the 2009 H1N1 pandemic strain were determined at day 0, day 28, and 6 months by hemagglutination-inhibition assay. A seroprotective response was a post-vaccination titer of ≥1:40 among those with a pre-vaccination level of ≤1:10. Geometric mean titers (GMT) and factors associated with higher levels were also evaluated.
We studied 127 participants with a median age of 35 (interquartile range (IQR) 28, 42) years. Among the HIV-infected arm (n=63), the median CD4 count was 595 (IQR 476, 819) cells/mm3 and 83% were receiving HAART. Thirty-five percent of all participants had a pre-vaccination level of >1:10. HIV-infected compared to HIV-uninfected adults were less likely to generate a seroprotective response at day 28 (54% vs. 75%, adjusted OR 0.23, p=0.021) or have a durable response at 6 months post-vaccination (28% vs. 56%, adjusted OR 0.19, p=0.005). Additionally, although pre-vaccination GMT were similar in both arms (median 7 vs. 8, p=0.11), the GMT at 6 months was significantly lower among HIV-infected versus HIV-uninfected adults (median 20 vs. 113, p=0.003). Among HIV-infected persons, younger age (p=0.035) and receipt of HAART (p=0.028) were associated with higher GMTs at 6 months.
Despite vaccination, most HIV-infected adults do not have durable seroprotective antibody responses to the 2009 influenza A (H1N1) virus, and hence may remain vulnerable to infection. In addition to HAART use, more immunogenic vaccines are likely needed for improving protection against influenza in this population.
PMCID: PMC3078993  PMID: 21371580
influenza; pandemic 2009 H1N1; vaccine responses; HIV; durability; long-term immunity
17.  Ceftaroline: A New Cephalosporin with Activity against Methicillin-Resistant Staphylococcus aureus (MRSA) 
Microbial resistance has reached alarming levels, threatening to outpace the ability to counter with more potent antimicrobial agents. In particular, methicillin-resistant Staphylococcus aureus (MRSA) has become a leading cause of skin and soft-tissue infections and PVL-positive strains have been associated with necrotizing pneumonia. Increasing reports of growing resistance to glycopeptides have been noted, further limiting the efficacy of standard antibiotics, such as vancomycin. Ceftaroline is a novel fifth-generation cephalosporin, which exhibits broad-spectrum activity against Gram-positive bacteria, including MRSA and extensively-resistant strains, such as vancomycin-intermediate S. aureus (VISA), heteroresistant VISA (hVISA), and vancomycin-resistant S. aureus (VRSA). In addition to being an exciting new agent in the anti-MRSA armamentarium, ceftaroline provides efficacy against many respiratory pathogens including Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Ceftaroline (600 mg intravenously every 12 hours) has been shown effective in phase III studies in the treatment of complicated skin and soft tissue infections and community-acquired pneumonia. To date, this unique antibiotic exhibits a low propensity for inducing resistance and has a good safety profile, although further post-marketing data and clinical experience are needed. In summary, ceftaroline provides an additional option for the management of complex multidrug resistant infections, including MRSA.
PMCID: PMC3140339  PMID: 21785568
Ceftaroline; antibiotic; cephalosporin; methicillin-resistant Staphylococcus aureus; MRSA; multidrug resistant organisms
18.  Immunogenicity of a Monovalent 2009 Influenza A (H1N1) Vaccine in an Immunocompromised Population: A Prospective Study Comparing HIV-Infected Adults with HIV-Uninfected Adults 
Background. Limited data exist on the immunogenicity of the 2009 influenza A (H1N1) vaccine among immunocompromised persons, including those with human immunodeficiency virus (HIV) infection.
Methods. We compared the immunogenicity and tolerability of a single dose of the monovalent 2009 influenza A (H1N1) vaccine (strain A/California/7/2009H1N1) between HIV-infected and HIV-uninfected adults 18–50 years of age. The primary end point was an antibody titer of ≥1:40 at day 28 after vaccination in those with a prevaccination level of ≤1:10, as measured by hemagglutination-inhibition assay. Geometric mean titers, influenza-like illnesses, and tolerability were also evaluated.
Results. One hundred thirty-one participants were evaluated (65 HIV-infected and 66 HIV-uninfected patients), with a median age of 35 years (interquartile range, 27–42 years). HIV-infected persons had a median CD4 cell count of 581 cells/mm3 (interquartile range, 476–814 cells/mm3) , and 82% were receiving antiretroviral medications. At baseline, 35 patients (27%) had antibody titers of >1:10. HIV-infected patients (29 [56%] of 52), compared with HIV-uninfected persons (35 [80%] of 44), were significantly less likely to develop an antibody response (odds ratio, .20; P = .003). Changes in the median geometric mean titer from baseline to day 28 were also significantly lower in HIV-infected patients than in HIV-uninfected persons (75 vs 153; P = .001). Five influenza-like illnesses occurred (2 cases in HIV-infected persons), but none was attributable to the 2009 influenza H1N1 virus. The vaccine was well tolerated in both groups.
Conclusions. Despite high CD4 cell counts and receipt of antiretroviral medications, HIV-infected adults generated significantly poorer antibody responses, compared with HIV-uninfected persons. Future studies evaluating a 2-dose series or more-immunogenic influenza A (H1N1) vaccines among HIV-infected adults are needed ( NCT00996970).
PMCID: PMC3060889  PMID: 21148532
19.  Hemoptysis Associated with Leptospirosis Acquired in Hawaii, USA 
Emerging Infectious Diseases  2011;17(12):2375-2377.
PMCID: PMC3311216  PMID: 22172093
leptospirosis; hemoptysis; bacteria; Hawaii; severe pulmonary hemorrhagic syndrome; SPHS; zoonosis; travel
20.  The Poplar-Poplar Rust Interaction: Insights from Genomics and Transcriptomics 
Journal of Pathogens  2011;2011:716041.
Poplars are extensively cultivated worldwide, and their susceptibility to the leaf rust fungus Melampsora larici-populina leads to considerable damages in plantations. Despite a good knowledge of the poplar rust life cycle, and particularly the epidemics on poplar, the perennial status of the plant host and the obligate biotrophic lifestyle of the rust fungus are bottlenecks for molecular investigations. Following the completion of both M. larici-populina and Populus trichocarpa genome sequences, gene families involved in poplar resistance or in rust fungus virulence were investigated, allowing the identification of key genetic determinants likely controlling the outcome of the interaction. Specific expansions of resistance and defense-related genes in poplar indicate probable innovations in perennial species in relation with host-pathogen interactions. The genome of M. Larici-populina contains a strikingly high number of genes encoding small secreted proteins (SSPs) representing hundreds of candidate effectors. Transcriptome analyses of interacting partners in compatible and incompatible interactions revealed conserved set of genes involved in poplar defense reactions as well as timely regulated expression of SSP transcripts during host tissues colonisation. Ongoing functional studies of selected candidate effectors will be achieved mainly on the basis of recombinant protein purification and subsequent characterisation.
PMCID: PMC3335510  PMID: 22567338
21.  Cost-Effectiveness Analysis of Diagnostic Options for Pneumocystis Pneumonia (PCP) 
PLoS ONE  2011;6(8):e23158.
Diagnosis of Pneumocystis jirovecii pneumonia (PCP) is challenging, particularly in developing countries. Highly sensitive diagnostic methods are costly, while less expensive methods often lack sensitivity or specificity. Cost-effectiveness comparisons of the various diagnostic options have not been presented.
Methods and Findings
We compared cost-effectiveness, as measured by cost per life-years gained and proportion of patients successfully diagnosed and treated, of 33 PCP diagnostic options, involving combinations of specimen collection methods [oral washes, induced and expectorated sputum, and bronchoalveolar lavage (BAL)] and laboratory diagnostic procedures [various staining procedures or polymerase chain reactions (PCR)], or clinical diagnosis with chest x-ray alone. Our analyses were conducted from the perspective of the government payer among ambulatory, HIV-infected patients with symptoms of pneumonia presenting to HIV clinics and hospitals in South Africa. Costing data were obtained from the National Institutes of Communicable Diseases in South Africa. At 50% disease prevalence, diagnostic procedures involving expectorated sputum with any PCR method, or induced sputum with nested or real-time PCR, were all highly cost-effective, successfully treating 77–90% of patients at $26–51 per life-year gained. Procedures using BAL specimens were significantly more expensive without added benefit, successfully treating 68–90% of patients at costs of $189–232 per life-year gained. A relatively cost-effective diagnostic procedure that did not require PCR was Toluidine Blue O staining of induced sputum ($25 per life-year gained, successfully treating 68% of patients). Diagnosis using chest x-rays alone resulted in successful treatment of 77% of patients, though cost-effectiveness was reduced ($109 per life-year gained) compared with several molecular diagnostic options.
For diagnosis of PCP, use of PCR technologies, when combined with less-invasive patient specimens such as expectorated or induced sputum, represent more cost-effective options than any diagnostic procedure using BAL, or chest x-ray alone.
PMCID: PMC3156114  PMID: 21858013
22.  The Syndrome of Perisylvian Polymicrogyria with Congenital Arthrogryposis 
Brain & development  2009;32(7):550-555.
Bilateral perisylvian polymicrogyria (BPP) is a well-recognized malformation of cortical development commonly associated with epilepsy, cognitive impairment, and oromotor apraxia. Reports have suggested the association of BPP with arthrogryposis multiplex congenita. We sought to investigate the clinical, electrophysiological, and neuroradiological features of this combined syndrome to determine if there are unique features that distinguish BPP with arthrogryposis from BPP alone.
Cases of BPP with congenital arthrogryposis were identified from a large research database of individuals with polymicrogyria. Clinical features (including oromotor function, seizures, and joint contractures), MR brain imaging, and results of neuromuscular testing were reviewed.
Ten cases of BPP with congenital arthrogryposis were identified. Most cases had some degree of oromotor apraxia. Only a few had seizures, but a majority of cases were still young children. Electrophysiological studies provided evidence for lower motor neuron or peripheral nervous system involvement. On brain imaging, bilateral polymicrogyria (PMG) centered along the Sylvian fissures was seen, with variable extension frontally or parietally; no other cortical malformations were present. We did not identify obvious neuroimaging features that distinguish this syndrome from that of BPP without arthrogryposis.
The clinical and neuroimaging features of the syndrome of BPP with congenital arthrogryposis appear similar to those seen in cases of isolated BPP without joint contractures, but electrophysiological studies often demonstrate coexistent lower motor neuron or peripheral nervous system pathology. These findings suggest that BPP with arthrogryposis may have a genetic etiology with effects at two levels of the neuraxis.
PMCID: PMC2888893  PMID: 19751967
Cortical malformation; dysplasia; perisylvian; polymicrogyria; contractures; arthrogryposis
23.  Telomerase as an important target of androgen-signaling blockade for prostate cancer treatment 
Molecular cancer therapeutics  2010;9(7):2016-2025.
As the mainstay treatment for advanced prostate cancer, androgen-deprivation therapy (ADT) targets the action of androgen receptor (AR) by reducing androgen level and/or by using anti-androgen to compete with androgens for binding to AR. Albeit effective in extending survival, ADT is associated with dose-limiting toxicity and the development of castration-resistant prostate cancer (CRPC) after prolonged use. Since CRPC is lethal and incurable, developing effective strategies to enhance the efficacy of ADT and circumvent resistance becomes an urgent task. Continuous AR signaling constitutes one major mechanism underlying the development of CRPC. The present study showed that methylseleninic acid (MSA), an agent that effectively reduces AR abundance, could enhance the cancer-killing efficacy of the anti-androgen bicalutamide in both androgen-dependent and castration-resistant prostate cancer cells. We found that combination of MSA and bicalutamide produced a robust downregulation of prostate-specific antigen and a recently identified AR target, telomerase and its catalytic subunit, telomere reverse transcriptase (hTERT). The downregulation of hTERT occurs mainly at the transcriptional level, and reduced AR occupancy of the promoter contributes to the downregulation. Furthermore, apoptosis induction by the two agents is significantly mitigated by restoration of hTERT. Our findings thus indicate that MSA in combination with anti-androgen could represent a viable approach to improve the therapeutic outcome of ADT. Given the critical role of hTERT/telomerase downregulation in mediating the combination effect and the fact that hTERT/telomerase could be measured in blood and urine, hTERT/telomerase could serve as an ideal tumor-specific biomarker to monitor the efficacy of the combination therapy non-invasively.
PMCID: PMC2901418  PMID: 20571066
anti-androgen; methylseleninic acid; androgen receptor; telomerase; prostate cancer
24.  Genome-wide analysis of eukaryote thaumatin-like proteins (TLPs) with an emphasis on poplar 
BMC Plant Biology  2011;11:33.
Plant inducible immunity includes the accumulation of a set of defense proteins during infection called pathogenesis-related (PR) proteins, which are grouped into families termed PR-1 to PR-17. The PR-5 family is composed of thaumatin-like proteins (TLPs), which are responsive to biotic and abiotic stress and are widely studied in plants. TLPs were also recently discovered in fungi and animals. In the poplar genome, TLPs are over-represented compared with annual species and their transcripts strongly accumulate during stress conditions.
Our analysis of the poplar TLP family suggests that the expansion of this gene family was followed by diversification, as differences in expression patterns and predicted properties correlate with phylogeny. In particular, we identified a clade of poplar TLPs that cluster to a single 350 kb locus of chromosome I and that are up-regulated by poplar leaf rust infection. A wider phylogenetic analysis of eukaryote TLPs - including plant, animal and fungi sequences - shows that TLP gene content and diversity increased markedly during land plant evolution. Mapping the reported functions of characterized TLPs to the eukaryote phylogenetic tree showed that antifungal or glycan-lytic properties are widespread across eukaryote phylogeny, suggesting that these properties are shared by most TLPs and are likely associated with the presence of a conserved acidic cleft in their 3D structure. Also, we established an exhaustive catalog of TLPs with atypical architectures such as small-TLPs, TLP-kinases and small-TLP-kinases, which have potentially developed alternative functions (such as putative receptor kinases for pathogen sensing and signaling).
Our study, based on the most recent plant genome sequences, provides evidence for TLP gene family diversification during land plant evolution. We have shown that the diverse functions described for TLPs are not restricted to specific clades but seem to be universal among eukaryotes, with some exceptions likely attributable to atypical protein structures. In the perennial plant model Populus, we unravelled the TLPs likely involved in leaf rust resistance, which will provide the foundation for further functional investigations.
PMCID: PMC3048497  PMID: 21324123
25.  Chloroplast genome sequencing analysis of Heterosigma akashiwo CCMP452 (West Atlantic) and NIES293 (West Pacific) strains 
BMC Genomics  2008;9:211.
Heterokont algae form a monophyletic group within the stramenopile branch of the tree of life. These organisms display wide morphological diversity, ranging from minute unicells to massive, bladed forms. Surprisingly, chloroplast genome sequences are available only for diatoms, representing two (Coscinodiscophyceae and Bacillariophyceae) of approximately 18 classes of algae that comprise this taxonomic cluster.
A universal challenge to chloroplast genome sequencing studies is the retrieval of highly purified DNA in quantities sufficient for analytical processing. To circumvent this problem, we have developed a simplified method for sequencing chloroplast genomes, using fosmids selected from a total cellular DNA library. The technique has been used to sequence chloroplast DNA of two Heterosigma akashiwo strains. This raphidophyte has served as a model system for studies of stramenopile chloroplast biogenesis and evolution.
H. akashiwo strain CCMP452 (West Atlantic) chloroplast DNA is 160,149 bp in size with a 21,822-bp inverted repeat, whereas NIES293 (West Pacific) chloroplast DNA is 159,370 bp in size and has an inverted repeat of 21,665 bp. The fosmid cloning technique reveals that both strains contain an isomeric chloroplast DNA population resulting from an inversion of their single copy domains. Both strains contain multiple small inverted and tandem repeats, non-randomly distributed within the genomes. Although both CCMP452 and NIES293 chloroplast DNAs contains 197 genes, multiple nucleotide polymorphisms are present in both coding and intergenic regions. Several protein-coding genes contain large, in-frame inserts relative to orthologous genes in other plastids. These inserts are maintained in mRNA products. Two genes of interest in H. akashiwo, not previously reported in any chloroplast genome, include tyrC, a tyrosine recombinase, which we hypothesize may be a result of a lateral gene transfer event, and an unidentified 456 amino acid protein, which we hypothesize serves as a G-protein-coupled receptor. The H. akashiwo chloroplast genomes share little synteny with other algal chloroplast genomes sequenced to date.
The fosmid cloning technique eliminates chloroplast isolation, does not require chloroplast DNA purification, and reduces sequencing processing time. Application of this method has provided new insights into chloroplast genome architecture, gene content and evolution within the stramenopile cluster.
PMCID: PMC2410131  PMID: 18462506

Results 1-25 (37)