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1.
J Nutr Biochem ; 116: 109324, 2023 06.
Article de Anglais | MEDLINE | ID: mdl-36963729

RÉSUMÉ

Skeletal muscle differentiation is an essential process in embryonic development as well as regeneration and repair throughout the lifespan. It is well-known that dietary fat intake impacts biological and physiological function in skeletal muscle, however, understanding of the contribution of nutritional factors in skeletal muscle differentiation is limited. Therefore, the objective of the current study was to evaluate the effects of free fatty acids (FFAs) on skeletal muscle differentiation in vitro. We used C2C12 murine myoblasts and treated them with various FFAs, which revealed a unique response of angiopoietin-like protein-4 (ANGPTL4) with linoleic acid (LA) treatment that was associated with reduced differentiation. LA significantly inhibited myotube formation and lowered the protein expression of myogenic regulatory factors, including MyoD and MyoG and increased Pax7 during cell differentiation. Next, recombinant ANGPTL4 protein or siRNA knockdown of ANGPTL4 was employed to examine its role in skeletal muscle differentiation, and we confirmed that ANGPTL4 knockdown at day two and six of differentiation restored myotube formation in the presence of LA. RNA-sequencing analysis revealed that ANGPTL4-mediated inhibition of skeletal muscle differentiation at day two as well as LA at day two or -6 led to a reduction in Wnt/ß-catenin signaling pathways. We confirmed that LA reduced Wnt11 and Axin2 while increasing expression of the Wnt inhibitor, Dkk2. ANGPTL4 knockdown increased ß-catenin protein in the nucleus in response to LA and increased Axin2 and Wnt11 expression. Taken together, these results demonstrate that LA induced ANGPTL4 inhibits C2C12 differentiation by suppressing Wnt/ß-catenin signaling.


Sujet(s)
Acide linoléique , bêta-Caténine , Souris , Animaux , bêta-Caténine/génétique , bêta-Caténine/métabolisme , Protéine-4 similaire à l'angiopoïétine/génétique , Protéine-4 similaire à l'angiopoïétine/métabolisme , Protéine-4 similaire à l'angiopoïétine/pharmacologie , Acide linoléique/pharmacologie , Acide linoléique/métabolisme , Différenciation cellulaire , Fibres musculaires squelettiques , Muscles squelettiques/métabolisme , Voie de signalisation Wnt , Développement musculaire
2.
Syst Parasitol ; 99(1): 41-62, 2022 02.
Article de Anglais | MEDLINE | ID: mdl-35028798

RÉSUMÉ

Previous morphological and histological data are supplemented with molecular and ultrastructural data for a Henneguya sp. isolated from farm-raised channel catfish Ictalurus punctatus in Mississippi, USA. Myxospores were cryptic, encapsulated within a thin layer of epithelium in the gill lamellae with spore measurements consistent with the original description of Henneguya postexilis Minchew, 1977. Myxospores were 42.7-49.1 µm in total length with spore bodies 12.1-17.2 × 3.6-4.8 × 2.9-3 µm. Polar capsules were of unequal length, with the longer capsule being 4.4-6.7 × 1.1-1.6 µm and the shorter capsule being 4.4-6.4 × 1.1-1.6 µm. Polar tubules had 6-8 turns. Caudal processes were 25.7-38.1 µm in length. Spores were encapsulated in a thin layer of epithelium in the gill lamellae. Molecular data from the most commonly used markers for myxozoan identification and phylogeny, partial 18S small subunit ribosomal gene (SSU), partial 28S large subunit ribosomal gene (LSU), and elongation factor 2 (EF2) were generated for H. postexilis. Additionally, novel data for LSU and EF2 were generated for archived myxozoan specimens from farm-raised catfish (H. mississippiensis, H. ictaluri, H. exilis, H. adiposa, H. sutherlandi, H. bulbosus, Unicauda fimbrethilae), as well as archived specimens from wild fish (H. laseeae [from Pylodictis olivaris], Hennegoides flockae [from Aphredoderus sayanus], Myxobolus cloutmani [from Cycleptus elongatus]. These include the first EF2 sequence data for the genera Hennegoides and Unicauda. Phylogenetic analyses using these data placed H. postexilis in well supported clades with other ictalurid-infecting Henneguya species. Phylogenetic signal assessments on these analyses suggest that while SSU provided the greatest phylogenetic signal, LSU yielded comparable signal, supporting previous work implying this region may be underutilised in reconstructing myxobolid phylogenies.


Sujet(s)
Maladies des poissons , Ictaluridae , Myxozoa , Parasites , Parasitoses animales , Animaux , Maladies des poissons/parasitologie , Branchies/parasitologie , Ictaluridae/parasitologie , Myxozoa/génétique , Parasitoses animales/parasitologie , Phylogenèse , Spécificité d'espèce
3.
J Biol Chem ; 296: 100183, 2021.
Article de Anglais | MEDLINE | ID: mdl-33310702

RÉSUMÉ

Many therapeutic monoclonal antibodies require binding to Fc γ receptors (FcγRs) for full effect and increasing the binding affinity increases efficacy. Preeminent among the five activating human FcγRs is FcγRIIIa/CD16a expressed by natural killer (NK) cells. CD16a is heavily processed, and recent reports indicate that the composition of the five CD16a asparagine(N)-linked carbohydrates (glycans) impacts affinity. These observations indicate that specific manipulation of CD16a N-glycan composition in CD16a-expressing effector cells including NK cells may improve treatment efficacy. However, it is unclear if modifying the expression of select genes that encode processing enzymes in CD16a-expressing effector cells is sufficient to affect N-glycan composition. We identified substantial processing differences using a glycoproteomics approach by comparing CD16a isolated from two NK cell lines, NK92 and YTS, with CD16a expressed by HEK293F cells and previous reports of CD16a from primary NK cells. Gene expression profiling by RNA-Seq and qRT-PCR revealed expression levels for glycan-modifying genes that correlated with CD16a glycan composition. These results identified a high degree of variability between the processing of the same human protein by different human cell types. N-glycan processing correlated with the expression of glycan-modifying genes and thus explained the substantial differences in CD16a processing by NK cells of different origins.


Sujet(s)
Cellules tueuses naturelles/métabolisme , Polyosides/génétique , Récepteurs du fragment Fc des IgG/métabolisme , Transcriptome , Lignée cellulaire , Glycopeptides/analyse , Glycopeptides/métabolisme , Cellules HEK293 , Humains , Cellules tueuses naturelles/composition chimique , Modèles moléculaires , Récepteurs du fragment Fc des IgG/composition chimique
4.
PLoS One ; 15(5): e0232120, 2020.
Article de Anglais | MEDLINE | ID: mdl-32407351

RÉSUMÉ

Decades of work indicate that female birds can control their offspring sex ratios in response to environmental and social cues. In laying hens, hormones administered immediately prior to sex chromosome segregation can exert sex ratio skews, indicating that these hormones may act directly on the germinal disc to influence which sex chromosome is retained in the oocyte and which is discarded into an unfertilizable polar body. We aimed to uncover the gene pathways involved in this process by testing whether treatments with testosterone or corticosterone that were previously shown to influence sex ratios elicit changes in the expression of genes and/or gene pathways involved in the process of meiotic segregation. We injected laying hens with testosterone, corticosterone, or control oil 5h prior to ovulation and collected germinal discs from the F1 preovulatory follicle in each hen 1.5h after injection. We used RNA-sequencing (RNA-seq) followed by DESeq2 and gene set enrichment analyses to identify genes and gene pathways that were differentially expressed between germinal discs of control and hormone-treated hens. Corticosterone treatment triggered downregulation of 13 individual genes, as well as enrichment of gene sets related to meiotic spindle organization and chromosome segregation, and additional gene sets that function in ion transport. Testosterone treatment triggered upregulation of one gene, and enrichment of one gene set that functions in nuclear chromosome segregation. This work indicates that corticosterone can be a potent regulator of meiotic processes and provides potential gene targets on which corticosterone and/or testosterone may act to influence offspring sex ratios in birds.


Sujet(s)
Corticostérone/pharmacologie , Régulation de l'expression des gènes/effets des médicaments et des substances chimiques , Méiose/effets des médicaments et des substances chimiques , Méiose/génétique , Follicule ovarique/cytologie , Ovulation , Testostérone/pharmacologie , Animaux , Poulets , Femelle , Follicule ovarique/effets des médicaments et des substances chimiques , Follicule ovarique/physiologie
5.
PLoS One ; 14(3): e0214274, 2019.
Article de Anglais | MEDLINE | ID: mdl-30908517

RÉSUMÉ

Mycobacterium chelonae is a member of the Mycobacterium chelonae-abscessus complex and a cause of opportunistic disease in fish, reptiles, birds, and mammals including humans. Isolates in the complex are often difficult to identify and have differing antimicrobial susceptibilities. Thirty-one previously identified rapidly-growing, non-tuberculous Mycobacterium sp. isolates cultured from biofilms, fish, reptiles, mammals, including humans, and three ATCC reference strains were evaluated with nine M. chelonae-abscessus complex whole genome sequences from GenBank by phylogenomic analysis, targeted gene comparisons, and in-vitro antimicrobial susceptibility patterns to assess strain variation among isolates from different sources. Results revealed minimal genetic variation among the M. chelonae strains. However, the core genomic alignment and SNP pattern of the complete 16S rRNA sequence clearly separated the turtle type strain ATCC 35752T from the clinical isolates and human reference strain "M. chelonae chemovar niacinogenes" ATCC 19237, providing evidence of two distinct subspecies. Concatenation of the partial rpoB (752 bp) and complete hsp65 (1,626 bp) sequence produced the same species/subspecies delineations as the core phylogeny. Partial rpoB and hsp65 sequences identified all the clinical isolates to the appropriate species level when respective cut-offs of 98% and 98.4% identity to the M. chelonae type strain ATCC 35752T were employed. The human strain, ATCC19237, was the most representative strain for the evaluated human, veterinary, and environmental strains. Additionally, two isolates were identified as Mycobacterium saopaulense, its first identification in a non-fish or non-human host.


Sujet(s)
Antibactériens/pharmacologie , Protéines bactériennes/génétique , Mycobacterium abscessus/classification , Séquençage du génome entier/méthodes , Animaux , Biofilms , Humains , Tests de sensibilité microbienne , Mycobacterium abscessus/effets des médicaments et des substances chimiques , Mycobacterium abscessus/isolement et purification , Phylogenèse , Polymorphisme de nucléotide simple , ARN ribosomique 16S/génétique , Spécificité d'espèce
6.
BMC Genomics ; 20(1): 143, 2019 Feb 18.
Article de Anglais | MEDLINE | ID: mdl-30777008

RÉSUMÉ

BACKGROUND: Genital C. trachomatis infection may cause pelvic inflammatory disease (PID) that can lead to tubal factor infertility (TFI). Understanding the pathogenesis of chlamydial complications including the pathophysiological processes within the female host genital tract is important in preventing adverse pathology. MicroRNAs regulate several pathophysiological processes of infectious and non-infectious etiologies. In this study, we tested the hypothesis that the miRNA profile of single and repeat genital chlamydial infections will be different and that these differences will be time dependent. Thus, we analyzed and compared differentially expressed mice genital tract miRNAs after single and repeat chlamydia infections using a C. muridarum mouse model. Mice were sacrificed and their genital tract tissues were collected at 1, 2, 4, and 8 weeks after a single and repeat chlamydia infections. Histopathology, and miRNA sequencing were performed. RESULTS: Histopathology presentation showed that the oviduct and uterus of reinfected mice were more inflamed, distended and dilated compared to mice infected once. The miRNAs expression profile was different in the reproductive tissues after a reinfection, with a greater number of miRNAs expressed after reinfection. Also, the number of miRNAs expressed each week after chlamydia infection and reinfection varied, with weeks eight and one having the highest number of differentially expressed miRNAs for chlamydia infection and reinfection respectively. Ten miRNAs; mmu-miR-378b, mmu-miR-204-5p, mmu-miR-151-5p, mmu-miR-142-3p, mmu-miR-128-3p, mmu-miR-335-3p, mmu-miR-195a-3p, mmu-miR-142-5p, mmu-miR-106a-5p and mmu-miR-92a-3p were common in both primary chlamydia infection and reinfection. Pathway analysis showed that, amongst other functions, the differentially regulated miRNAs control pathways involved in cellular and tissue development, disease conditions and toxicity. CONCLUSIONS: This study provides insights into the changes in miRNA expression over time after chlamydia infection and reinfection, as well as the pathways they regulate to determine pathological outcomes. The miRNAs networks generated in our study shows that there are differences in the focus molecules involved in significant biological functions in chlamydia infection and reinfection, implying that chlamydial pathogenesis occurs differently for each type of infection and that this could be important when determining treatments regime and disease outcome. The study underscores the crucial role of host factors in chlamydia pathogenesis.


Sujet(s)
Infections à Chlamydia/génétique , Infections à Chlamydia/microbiologie , Chlamydia , Système génital/microbiologie , microARN/génétique , Transcriptome , Animaux , Biopsie , Lignée cellulaire , Infections à Chlamydia/anatomopathologie , Biologie informatique/méthodes , Modèles animaux de maladie humaine , Femelle , Analyse de profil d'expression de gènes , Régulation de l'expression des gènes , Système génital/anatomopathologie , Humains , Immunohistochimie , Souris
7.
Article de Anglais | MEDLINE | ID: mdl-33777408

RÉSUMÉ

Lymphatic filariasis (LF) threatens nearly 20% of the world's population and has handicapped one-third of the 120 million people currently infected. Current control and elimination programs for LF rely on mass drug administration of albendazole plus diethylcarbamazine (DEC) or ivermectin. Only the mechanism of action of albendazole is well understood. To gain a better insight into antifilarial drug action in vivo, we treated gerbils harbouring patent Brugia malayi infections with 6 mg kg-1 DEC, 0.15 mg kg-1 ivermectin or 1 mg kg-1 albendazole. Treatments had no effect on the numbers of worms present in the peritoneal cavity of treated animals, so effects on gene expression were a direct result of the drug and not complicated by dying parasites. Adults and microfilariae were collected 1 and 7 days post-treatment and RNA isolated for transcriptomic analysis. The experiment was repeated three times. Ivermectin treatment produced the most differentially expressed genes (DEGs), 113. DEC treatment yielded 61 DEGs. Albendazole treatment resulted in little change in gene expression, with only 6 genes affected. In total, nearly 200 DEGs were identified with little overlap between treatment groups, suggesting that these drugs may interfere in different ways with processes important for parasite survival, development, and reproduction.

8.
Avian Dis ; 63(3): 531-538, 2019 09 01.
Article de Anglais | MEDLINE | ID: mdl-31967440

RÉSUMÉ

In this case report, we describe the pathologic changes and the ultrastructural and molecular characteristics of an adenovirus in a sun conure (Aratinga solstitialis) that presented with a history of sudden death. On histologic examination, there was multifocal hepatic and splenic necrosis. Within some hepatocytes and unidentified cells in the spleen, renal interstitial fibroblasts, and ovarian stroma were intranuclear amphophilic inclusion bodies. Electron microscopy of affected tissue showed intranuclear icosahedral viral particles with an inner capsid (29.2-33.8 nm in diameter) and an outer capsid (70.2-71.7 nm in diameter). Next-generation sequencing and BLAST analysis of complementary DNA synthesized from RNA extracted from formalin-fixed tissues showed an adenovirus, designated sun conure adenovirus (SCAdv). A DNA in situ hybridization (ISH) probe, constructed from the SCAdv and similar sequences from GenBank, was also positive in the intranuclear inclusion bodies, whereas standard ISH for psittacine adenovirus 1 was negative. These results show that ancillary diagnostic testing, such as next-generation sequencing, even using formalin-fixed, paraffin-embedded tissues, along with ISH, can be useful in identifying additional, unknown viruses that show similar pathology to commonly known viruses but do not show up as positive on routine diagnostic tests.


Reporte de caso- Cambios histopatológicos, ultraestructura y caracterización molecular de un adenovirus en una cotorra solar (Aratinga solstitialis). En este reporte de caso, se describen los cambios patológicos y las características ultraestructurales y moleculares de un adenovirus en una cotorra solar (Aratinga solstitialis) que se presentó con un historial de muerte súbita. En el examen histológico, hubo necrosis hepática y esplénica multifocal. Dentro de algunos hepatocitos y células no identificadas en el bazo, los fibroblastos intersticiales renales y en el estroma ovárico se encontraron cuerpos de inclusión anfofílicos intranucleares. La microscopía electrónica del tejido afectado mostró partículas víricas intranucleares icosaédricas con una cápside interna (de 29.2 a 33.8 nm de diámetro) y una cápside externa (de 70.2 a 71.7 nm de diámetro). Mediante el análisis de secuenciación de segunda generación y por la Herramienta de Búsqueda de Alineaciones Local Básica (con siglas en inglés BLAST) del ADN complementario sintetizado a partir de ARN extraído de tejidos fijados con formalina mostraron un adenovirus, denominado adenovirus de cotorra solar (SCAdv). Se construyó una sonda de ADN para hibridación in situ (ISH), a partir de la secuencia del virus SCAdv y de secuencias similares de GenBank, que generó reacción positiva en los cuerpos de inclusión intranucleares, mientras que la hibridación in situ estándar para el adenovirus I de psitácidos fue negativa. Estos resultados muestran que las pruebas de diagnóstico complementarias, como la secuenciación de segunda generación, utilizando tejidos fijados con formalina e incluidos en parafina junto con la hibridación in situ pueden ser útiles para identificar virus adicionales desconocidos que muestran una patología similar a los virus comúnmente conocidos, pero que no se detectan con las pruebas diagnósticas de rutina.


Sujet(s)
Infections à Adenoviridae/médecine vétérinaire , Maladies des oiseaux/anatomopathologie , Perroquets , Siadenovirus/isolement et purification , Infections à Adenoviridae/anatomopathologie , Infections à Adenoviridae/virologie , Animaux , Séquence nucléotidique , Maladies des oiseaux/virologie , Protéines de capside/analyse , Issue fatale , Femelle , Phylogenèse , Alignement de séquences , Siadenovirus/génétique
9.
Int J Parasitol Drugs Drug Resist ; 8(3): 587-595, 2018 12.
Article de Anglais | MEDLINE | ID: mdl-30279092

RÉSUMÉ

Mass administration of macrocyclic lactones targets the transmission of the causative agents of lymphatic filariasis to their insect vectors by rapidly clearing microfilariae (Mf) from the circulation. It has been proposed that the anti-filarial action of these drugs may be mediated through the host immune system. We recently developed an in vitro assay for monitoring the attachment to and killing of B. malayi Mf by human neutrophils (PMNs) and monocytes (PBMCs), however, the levels of both cell to worm attachment and leukocyte mediated Mf killing varied greatly between individual experiments. To determine whether differences in an individual's immune cells or the Mf themselves might account for the variability in survival, PMNs and PBMCs were isolated from 12 donors every week for 4 weeks and the cells used for survival assays with a different batch of Mf, thereby keeping donors constant but varying the Mf sample. Results from these experiments indicate that, overall, killing is Mf-rather than donor-dependent. To assess whether ivermectin (IVM) or diethylcarbamazine (DEC) increase killing, Mf were incubated either alone or with immune cells in the presence of IVM or DEC. Neither drug induced a significant difference in the survival of Mf whether cultured with or without cells, with the exception of DEC at 2 h post incubation. In addition, human PBMCs and PMNs were incubated with IVM or DEC for 1 h or 16 h prior to RNA extraction and Illumina sequencing. Although donor-to-donor variation may mask subtle differences in gene expression, principle component analysis of the RNASeq data indicates that there is no significant change in the expression of any genes from the treated cells versus controls. Together these data suggest that IVM and DEC have little direct effect on immune cells involved in the rapid clearance of Mf from the circulation.


Sujet(s)
Brugia malayi/effets des médicaments et des substances chimiques , Ivermectine/pharmacologie , Microfilaria/immunologie , Monocytes/effets des médicaments et des substances chimiques , Granulocytes neutrophiles/effets des médicaments et des substances chimiques , Animaux , Brugia malayi/génétique , Brugia malayi/immunologie , Brugia malayi/physiologie , Diéthylcarbamazine/pharmacologie , Filariose lymphatique/immunologie , Filariose lymphatique/parasitologie , Filaricides/pharmacologie , Séquençage nucléotidique à haut débit , Humains , Microfilaria/effets des médicaments et des substances chimiques , Monocytes/immunologie , Monocytes/parasitologie , Granulocytes neutrophiles/immunologie , Granulocytes neutrophiles/parasitologie
10.
BMC Genomics ; 16: 352, 2015 May 06.
Article de Anglais | MEDLINE | ID: mdl-25943104

RÉSUMÉ

BACKGROUND: During their lifetime, conifer trees are exposed to numerous herbivorous insects. To protect themselves against pests, trees have developed a broad repertoire of protective mechanisms. Many of the plant's defence reactions are activated upon an insect attack, and the underlying regulatory mechanisms are not entirely understood yet, in particular in conifer trees. Here, we present the results of our studies on the transcriptional response and the volatile compounds production of Scots pine (Pinus sylvestris) upon the large pine weevil (Hylobius abietis) feeding. RESULTS: Transcriptional response of Scots pine to the weevil attack was investigated using a novel customised 36.4 K Pinus taeda microarray. The weevil feeding caused large-scale changes in the pine transcriptome. In total, 774 genes were significantly up-regulated more than 4-fold (p≤0.05), whereas 64 genes were significantly down-regulated more than 4-fold. Among the up-regulated genes, we could identify genes involved in signal perception, signalling pathways, transcriptional regulation, plant hormone homeostasis, secondary metabolism and defence responses. The weevil feeding on stem bark of pine significantly increased the total emission of volatile organic compounds from the undamaged stem bark area. The emission levels of monoterpenes and sesquiterpenes were also increased. Interestingly, we could not observe any correlation between the increased production of the terpenoid compounds and expression levels of the terpene synthase-encoding genes. CONCLUSIONS: The obtained data provide an important insight into the transcriptional response of conifer trees to insect herbivory and illustrate the massive changes in the host transcriptome upon insect attacks. Moreover, many of the induced pathways are common between conifers and angiosperms. The presented results are the first ones obtained by the use of a microarray platform with an extended coverage of pine transcriptome (36.4 K cDNA elements). The platform will further facilitate the identification of resistance markers with the direct relevance for conifer tree breeding.


Sujet(s)
Consommation alimentaire , Herbivorie , Pinus/physiologie , Écorce/physiologie , Charançons/physiologie , Animaux , Paroi cellulaire/métabolisme , Analyse de profil d'expression de gènes , Homéostasie , Pinus/cytologie , Pinus/génétique , Pinus/métabolisme , Écorce/cytologie , Écorce/génétique , Écorce/métabolisme , Facteur de croissance végétal/métabolisme , Transduction du signal , Transcription génétique , Composés organiques volatils/métabolisme
11.
Genome Biol ; 15(3): R59, 2014 Mar 04.
Article de Anglais | MEDLINE | ID: mdl-24647006

RÉSUMÉ

BACKGROUND: The size and complexity of conifer genomes has, until now, prevented full genome sequencing and assembly. The large research community and economic importance of loblolly pine, Pinus taeda L., made it an early candidate for reference sequence determination. RESULTS: We develop a novel strategy to sequence the genome of loblolly pine that combines unique aspects of pine reproductive biology and genome assembly methodology. We use a whole genome shotgun approach relying primarily on next generation sequence generated from a single haploid seed megagametophyte from a loblolly pine tree, 20-1010, that has been used in industrial forest tree breeding. The resulting sequence and assembly was used to generate a draft genome spanning 23.2 Gbp and containing 20.1 Gbp with an N50 scaffold size of 66.9 kbp, making it a significant improvement over available conifer genomes. The long scaffold lengths allow the annotation of 50,172 gene models with intron lengths averaging over 2.7 kbp and sometimes exceeding 100 kbp in length. Analysis of orthologous gene sets identifies gene families that may be unique to conifers. We further characterize and expand the existing repeat library based on the de novo analysis of the repetitive content, estimated to encompass 82% of the genome. CONCLUSIONS: In addition to its value as a resource for researchers and breeders, the loblolly pine genome sequence and assembly reported here demonstrates a novel approach to sequencing the large and complex genomes of this important group of plants that can now be widely applied.


Sujet(s)
Cartographie de contigs/méthodes , Génome végétal , Pinus taeda/génétique , Analyse de séquence d'ADN/méthodes , ADN des plantes/génétique , Haploïdie
12.
J Econ Entomol ; 107(5): 1931-45, 2014 10 01.
Article de Anglais | MEDLINE | ID: mdl-26309284

RÉSUMÉ

During oviposition, female Sirex noctilio (F.) (Siricidae) woodwasps inject their conifer hosts with a venom gland secretion. The secretion induces a variety of host physiological changes that facilitate subsequent lethal infection by a symbiotic fungus. A heat-stable factor that can migrate from the site of oviposition in the trunk through the xylem to needles in the crown of attacked pines was purified by size-fractionation and reversed-phase-high-performance liquid chromatography using activity assays based on defense gene induction as well as the needle wilt response in pine shoot explants. An 11-amino acid, posttranslationally modified peptide (SEGPROGTKRP) encoded by the most abundant transcript recovered from S. noctilio venom gland tissue comprised the backbone of the 1,850 Da active factor. Posttranslational modifications included hydroxylation of a Pro residue at position 6 as well as O-glycosylation of Ser and Thr residues at positions 1 and 8, respectively. The O-linked sugars were identical α-linked N-acetylgalactosamine residues modified at the C6 position by addition of phosphoethanolamine. In contrast to the native peptide, a synthetic version of the hydroxylated peptide backbone lacking the glycosyl side chains failed to induce pine defense genes or cause needle wilt in excised shoots. This peptide, hereafter called noctilisin, is related to the O-glycosylated short-chain proline-rich antimicrobial peptides exemplified by drosocin. The noctilisin structure contains motifs which may explain how it avoids detection by pine defense systems.


Sujet(s)
Venins d'arthropode/pharmacologie , Glycopeptides/pharmacologie , Hymenoptera/physiologie , Protéines d'insecte/pharmacologie , Pinus/physiologie , Séquence d'acides aminés , Animaux , Venins d'arthropode/génétique , Séquence nucléotidique , Femelle , Glycopeptides/génétique , Hymenoptera/génétique , Protéines d'insecte/génétique , Pinus/génétique , Pinus/immunologie , Feuilles de plante/immunologie , Feuilles de plante/physiologie
13.
BMC Plant Biol ; 13: 123, 2013 Aug 30.
Article de Anglais | MEDLINE | ID: mdl-23987738

RÉSUMÉ

BACKGROUND: It is during embryogenesis that the plant body plan is established and the meristems responsible for all post-embryonic growth are specified. The molecular mechanisms governing conifer embryogenesis are still largely unknown. Their elucidation may contribute valuable information to clarify if the distinct features of embryo development in angiosperms and gymnosperms result from differential gene regulation. To address this issue, we have performed the first transcriptomic analysis of zygotic embryo development in a conifer species (Pinus pinaster) focusing our study in particular on regulatory genes playing important roles during plant embryo development, namely epigenetic regulators and transcription factors. RESULTS: Microarray analysis of P. pinaster zygotic embryogenesis was performed at five periods of embryo development from early developing to mature embryos. Our results show that most changes in transcript levels occurred in the first and the last embryo stage-to-stage transitions, namely early to pre-cotyledonary embryo and cotyledonary to mature embryo. An analysis of functional categories for genes that were differentially expressed through embryogenesis highlighted several epigenetic regulation mechanisms. While putative orthologs of transcripts associated with mechanisms that target transposable elements and repetitive sequences were strongly expressed in early embryogenesis, PRC2-mediated repression of genes seemed more relevant during late embryogenesis. On the other hand, functions related to sRNA pathways appeared differentially regulated across all stages of embryo development with a prevalence of miRNA functions in mid to late embryogenesis. Identification of putative transcription factor genes differentially regulated between consecutive embryo stages was strongly suggestive of the relevance of auxin responses and regulation of auxin carriers during early embryogenesis. Such responses could be involved in establishing embryo patterning. Later in development, transcripts with homology to genes acting on modulation of auxin flow and determination of adaxial-abaxial polarity were up-regulated, as were putative orthologs of genes required for meristem formation and function as well as establishment of organ boundaries. Comparative analysis with A. thaliana embryogenesis also highlighted genes involved in auxin-mediated responses, as well as epigenetic regulation, indicating highly correlated transcript profiles between the two species. CONCLUSIONS: This is the first report of a time-course transcriptomic analysis of zygotic embryogenesis in a conifer. Taken together our results show that epigenetic regulation and transcriptional control related to auxin transport and response are critical during early to mid stages of pine embryogenesis and that important events during embryogenesis seem to be coordinated by putative orthologs of major developmental regulators in angiosperms.


Sujet(s)
Épigenèse génétique/génétique , Pinus/embryologie , Pinus/génétique , Graines/génétique , Régulation de l'expression des gènes végétaux/génétique , Régulation de l'expression des gènes végétaux/physiologie , Acides indolacétiques/métabolisme , Séquençage par oligonucléotides en batterie , Pinus/métabolisme , Protéines végétales/génétique , Graines/métabolisme
14.
BMC Genomics ; 14: 137, 2013 Feb 28.
Article de Anglais | MEDLINE | ID: mdl-23445355

RÉSUMÉ

BACKGROUND: Douglas-fir (Pseudotsuga menziesii), one of the most economically and ecologically important tree species in the world, also has one of the largest tree breeding programs. Although the coastal and interior varieties of Douglas-fir (vars. menziesii and glauca) are native to North America, the coastal variety is also widely planted for timber production in Europe, New Zealand, Australia, and Chile. Our main goal was to develop a SNP resource large enough to facilitate genomic selection in Douglas-fir breeding programs. To accomplish this, we developed a 454-based reference transcriptome for coastal Douglas-fir, annotated and evaluated the quality of the reference, identified putative SNPs, and then validated a sample of those SNPs using the Illumina Infinium genotyping platform. RESULTS: We assembled a reference transcriptome consisting of 25,002 isogroups (unique gene models) and 102,623 singletons from 2.76 million 454 and Sanger cDNA sequences from coastal Douglas-fir. We identified 278,979 unique SNPs by mapping the 454 and Sanger sequences to the reference, and by mapping four datasets of Illumina cDNA sequences from multiple seed sources, genotypes, and tissues. The Illumina datasets represented coastal Douglas-fir (64.00 and 13.41 million reads), interior Douglas-fir (80.45 million reads), and a Yakima population similar to interior Douglas-fir (8.99 million reads). We assayed 8067 SNPs on 260 trees using an Illumina Infinium SNP genotyping array. Of these SNPs, 5847 (72.5%) were called successfully and were polymorphic. CONCLUSIONS: Based on our validation efficiency, our SNP database may contain as many as ~200,000 true SNPs, and as many as ~69,000 SNPs that could be genotyped at ~20,000 gene loci using an Infinium II array-more SNPs than are needed to use genomic selection in tree breeding programs. Ultimately, these genomic resources will enhance Douglas-fir breeding and allow us to better understand landscape-scale patterns of genetic variation and potential responses to climate change.


Sujet(s)
Analyse de profil d'expression de gènes/méthodes , Polymorphisme de nucléotide simple , Pseudotsuga/génétique , Génotype , Séquençage nucléotidique à haut débit , Internet , Annotation de séquence moléculaire , Séquençage par oligonucléotides en batterie , Reproductibilité des résultats
15.
Tree Physiol ; 32(10): 1302-12, 2012 Oct.
Article de Anglais | MEDLINE | ID: mdl-23042767

RÉSUMÉ

Sirex noctilio F., a Eurasian horntail woodwasp recently introduced into North America, oviposits in pines and other conifers and in the process spreads a phytopathogenic fungus that serves as a food source for its larvae. During oviposition the woodwasp also deposits mucus produced in its acid (venom) gland that alters pine defense responses and facilitates infection by the fungus. A 26,496-feature loblolly pine cDNA microarray was used to survey gene expression of pine tissue responding to S. noctilio venom. Six genes were selected for further assessment by quantitative real-time polymerase chain reaction (qRT-PCR), including one that encoded an apparent PR-4 protein and another that encoded a thaumatin-like protein. Expression of both was strongly induced in response to venom, while expression of an apparent actin gene (ACT1) was stable in response to the venom. The pattern of gene response was similar in Pinus taeda L. and Pinus radiata D. Don, but the magnitude of response in P. radiata was significantly stronger for each of the induced genes. The magnitude of the biomarker gene response to venom also varied according to genotype within these two species. The qRT-PCR assay was used to demonstrate that the primary bioactive component in S. noctilio venom is a polypeptide.


Sujet(s)
Régulation de l'expression des gènes végétaux/effets des médicaments et des substances chimiques , Hymenoptera/composition chimique , Pinus taeda/génétique , Pinus/génétique , Maladies des plantes/parasitologie , Venins de guêpe/pharmacologie , Animaux , Marqueurs biologiques/analyse , Femelle , Analyse de profil d'expression de gènes , Gènes de plante/génétique , Génotype , Interactions hôte-parasite , Hymenoptera/physiologie , Annotation de séquence moléculaire , Amérique du Nord , Séquençage par oligonucléotides en batterie , Peptides , Phénotype , Pinus/effets des médicaments et des substances chimiques , Pinus/parasitologie , Pinus taeda/effets des médicaments et des substances chimiques , Pinus taeda/parasitologie , Protéolyse , ARN des plantes/génétique , Plant/effets des médicaments et des substances chimiques , Plant/génétique , Plant/parasitologie , Spécificité d'espèce , Stress physiologique , Venins de guêpe/isolement et purification
16.
BMC Genomics ; 13 Suppl 3: S1, 2012 Jun 11.
Article de Anglais | MEDLINE | ID: mdl-22759610

RÉSUMÉ

BACKGROUND: Phenylalanine ammonia lyase (PAL) is a key enzyme of the phenylpropanoid pathway that catalyzes the deamination of phenylalanine to trans-cinnamic acid, a precursor for the lignin and flavonoid biosynthetic pathways. To date, PAL genes have been less extensively studied in gymnosperms than in angiosperms. Our interest in PAL genes stems from their potential role in the defense responses of Pinus taeda, especially with respect to lignification and production of low molecular weight phenolic compounds under various biotic and abiotic stimuli. In contrast to all angiosperms for which reference genome sequences are available, P. taeda has previously been characterized as having only a single PAL gene. Our objective was to re-evaluate this finding, assess the evolutionary history of PAL genes across major angiosperm and gymnosperm lineages, and characterize PAL gene expression patterns in Pinus taeda. METHODS: We compiled a large set of PAL genes from the largest transcript dataset available for P. taeda and other conifers. The transcript assemblies for P. taeda were validated through sequencing of PCR products amplified using gene-specific primers based on the putative PAL gene assemblies. Verified PAL gene sequences were aligned and a gene tree was estimated. The resulting gene tree was reconciled with a known species tree and the time points for gene duplication events were inferred relative to the divergence of major plant lineages. RESULTS: In contrast to angiosperms, gymnosperms have retained a diverse set of PAL genes distributed among three major clades that arose from gene duplication events predating the divergence of these two seed plant lineages. Whereas multiple PAL genes have been identified in sequenced angiosperm genomes, all characterized angiosperm PAL genes form a single clade in the gene PAL tree, suggesting they are derived from a single gene in an ancestral angiosperm genome. The five distinct PAL genes detected and verified in P. taeda were derived from a combination of duplication events predating and postdating the divergence of angiosperms and gymnosperms. CONCLUSIONS: Gymnosperms have a more phylogenetically diverse set of PAL genes than angiosperms. This inference has contrasting implications for the evolution of PAL gene function in gymnosperms and angiosperms.


Sujet(s)
Cycadopsida/génétique , Analyse de profil d'expression de gènes , Phenylalanine ammonia-lyase/génétique , Pinus taeda/génétique , Protéines végétales/génétique , Séquence d'acides aminés , Séquence nucléotidique , Cycadopsida/classification , Cycadopsida/enzymologie , Régulation de l'expression des gènes codant pour des enzymes , Régulation de l'expression des gènes végétaux , Magnoliopsida/classification , Magnoliopsida/enzymologie , Magnoliopsida/génétique , Données de séquences moléculaires , Phenylalanine ammonia-lyase/classification , Phylogenèse , Pinus taeda/enzymologie , Tiges de plante/enzymologie , Tiges de plante/génétique , Plant/enzymologie , Plant/génétique , Similitude de séquences d'acides aminés , Similitude de séquences d'acides nucléiques
17.
Br J Cancer ; 106(5): 826-38, 2012 Feb 28.
Article de Anglais | MEDLINE | ID: mdl-22315052

RÉSUMÉ

BACKGROUND: Despite thousands of papers, the value of quality of life (QoL) in curing disease remains uncertain. Until now, we lacked tools for the diagnosis and specific treatment of diseased QoL. We approached this problem stepwise by theory building, modelling, an exploratory trial and now a definitive randomised controlled trial (RCT) in breast cancer, whose results we report here. METHODS: In all, 200 representative Bavarian primary breast cancer patients were recruited by five hospitals and treated by 146 care professionals. Patients were randomised to either (1) a novel care pathway including diagnosis of 'diseased' QoL (any QoL measure below 50 points) using a QoL profile and expert report sent to the patient's coordinating practitioner, who arranged QoL therapy consisting of up to five standardised treatments for specific QoL defects or (2) standard postoperative care adhering to the German national guideline for breast cancer. The primary end point was the proportion of patients in each group with diseased QoL 6 months after surgery. Patients were blinded to their allocated group. RESULTS: At 0 and 3 months after surgery, diseased QoL was diagnosed in 70% of patients. The QoL pathway reduced rates of diseased QoL to 56% at 6 months, especially in emotion and coping, compared with 71% in controls (P=0.048). Relative risk reduction was 21% (95% confidence interval (CI): 0-37), absolute risk reduction 15% (95% CI: 0.3-29), number needed to treat (NNT)=7 (95% CI: 3-37). When QoL therapy finished after successful treatment, diseased QoL often returned again, indicating good responsiveness of the QoL pathway. CONCLUSION: A three-component outcome system including clinician-derived objective, patient-reported subjective end points and qualitative analysis of clinical relevance was developed in the last 10 years for cancer as a complex intervention. A separate QoL pathway was implemented for the diagnosis and treatment of diseased QoL and its effectiveness tested in a community-based, pragmatic, definitive RCT. While the pathway was active, it was effective with an NNT of 7.


Sujet(s)
Tumeurs du sein/psychologie , Tumeurs du sein/thérapie , Qualité de vie , Adaptation psychologique , Tumeurs du sein/chirurgie , Détermination du point final , Femelle , Humains , Nombre de sujets à traiter , Méthode en simple aveugle , Enquêtes et questionnaires
18.
Phys Rev Lett ; 107(9): 097201, 2011 Aug 26.
Article de Anglais | MEDLINE | ID: mdl-21929263

RÉSUMÉ

A thermodynamic method to extract the interchain coupling (IC) of spatially anisotropic 2D or 3D spin-1/2 systems from their empirical saturation field H(s) (T=0) is proposed. Using modern theoretical methods we study how H(s) is affected by an antiferromagnetic (AFM) IC between frustrated chains described in the J(1)-J(2)-spin model with ferromagnetic 1st and AFM 2nd neighbor in-chain exchange. A complex 3D-phase diagram has been found. For Li(2)CuO(2) and Ca(2)Y(2)Cu(5)O(10), we show that H(s) is solely determined by the IC and predict H(s)≈61 T for the latter. With H(s)≈55 T from magnetization data one reads out a weak IC for Li(2)CuO(2) close to that obtained from inelastic neutron scattering.

20.
BMC Genomics ; 12: 264, 2011 May 24.
Article de Anglais | MEDLINE | ID: mdl-21609476

RÉSUMÉ

BACKGROUND: Global transcriptional analysis of loblolly pine (Pinus taeda L.) is challenging due to limited molecular tools. PtGen2, a 26,496 feature cDNA microarray, was fabricated and used to assess drought-induced gene expression in loblolly pine propagule roots. Statistical analysis of differential expression and weighted gene correlation network analysis were used to identify drought-responsive genes and further characterize the molecular basis of drought tolerance in loblolly pine. RESULTS: Microarrays were used to interrogate root cDNA populations obtained from 12 genotype × treatment combinations (four genotypes, three watering regimes). Comparison of drought-stressed roots with roots from the control treatment identified 2445 genes displaying at least a 1.5-fold expression difference (false discovery rate = 0.01). Genes commonly associated with drought response in pine and other plant species, as well as a number of abiotic and biotic stress-related genes, were up-regulated in drought-stressed roots. Only 76 genes were identified as differentially expressed in drought-recovered roots, indicating that the transcript population can return to the pre-drought state within 48 hours. Gene correlation analysis predicts a scale-free network topology and identifies eleven co-expression modules that ranged in size from 34 to 938 members. Network topological parameters identified a number of central nodes (hubs) including those with significant homology (E-values ≤ 2 × 10-30) to 9-cis-epoxycarotenoid dioxygenase, zeatin O-glucosyltransferase, and ABA-responsive protein. Identified hubs also include genes that have been associated previously with osmotic stress, phytohormones, enzymes that detoxify reactive oxygen species, and several genes of unknown function. CONCLUSION: PtGen2 was used to evaluate transcriptome responses in loblolly pine and was leveraged to identify 2445 differentially expressed genes responding to severe drought stress in roots. Many of the genes identified are known to be up-regulated in response to osmotic stress in pine and other plant species and encode proteins involved in both signal transduction and stress tolerance. Gene expression levels returned to control values within a 48-hour recovery period in all but 76 transcripts. Correlation network analysis indicates a scale-free network topology for the pine root transcriptome and identifies central nodes that may serve as drivers of drought-responsive transcriptome dynamics in the roots of loblolly pine.


Sujet(s)
Sécheresses , Réseaux de régulation génique , Séquençage par oligonucléotides en batterie/méthodes , Pinus taeda/génétique , Racines de plante/génétique , Stress physiologique/génétique , Étiquettes de séquences exprimées/métabolisme , Génomique , Pinus taeda/physiologie , Racines de plante/physiologie , ARN messager/génétique , ARN messager/métabolisme , Reproductibilité des résultats
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