Identification of mechanisms involved in mastitis response by means of gene network building.

Mastitis, an inflammation of the mammary gland, is the most prevalent and costly production disease in dairy herds worldwide. It is caused generally by bacteria and accounts for a significant decrease in milk production and quality. One promising approach to reduce problems caused by mastitis, in addition to sanitary care, is the selection of animals resistant to disease and the incorporation of this trait into the herds. Therefore, studies to better understand the mechanisms involved in animal response to this disease are essential to the proposition of new advances in area. In this context, the aim of this study was to identify groups of genes involved in cow response to mastitis infection, through gene network building from microarray data. Gene expression data from the GeneChipâ Bovine Genome Array (Affymetrix) hybridization with milk somatic cells samples from Holstein-Zebu crossbreed dairy cows, obtained before (B) and 24 hrs after (A) artificial infection with Staphylococcus agalactiae, were analyzed using a network building methodology based on gene co-expression. We used WGCNA (Weighted Gene Co-expression Analysis), a systems biology method for describing the correlation patterns among genes across microarray samples, that can be used for finding clusters (modules) of highly correlated genes to identify modules of co-expressed genes, which may correspond to functionally related genes. By comparing two networks (between contrasting data sets), conserved and non-conserved modules can be identified. This strategy, named differential network analysis, aims to identify genes groups that are both differentially expressed and differentially connected, and changes in connectivity may correspond to large-scale rewiring, in response to environmental changes and/or physiologic perturbations. Two microarray data sets, B (n=5) and A (n=5), were preprocessed using affy and gcrma R/Bioconductor packages. A filter was applied, which resulted in the use of only those transcripts present in all samples. Gene co-expression networks were identified separately for each group (B and A), by the R/WGCNA package. Gene networks were compared between the two groups, and non-conserved modules were uncovered from a correlation test of the connectivity values. Our analysis identified a total of 17 modules of co-expressed genes, three of them, designed by the colors grey (n=35), blue (n=37) and turquoise (n=192), non-conserved between the groups. Using Blast2GO for enrichment analysis, we find the molecular function Protein Binding overrepresented in all three modules. However, in despite of the same molecular function, each one of the modules showed distinct characteristcs. Genes of grey module (BTG3, CD3E, MBD1, CHIC2, PLXNA3, MOCS3, NEIL1, VPS45, BCL2) were related to apoptosis and antigen recognition. Genes of turquoise module were enriched in inflammation mediators, including known mastitis marker genes (FGL1, GJA1, F2RL1, PTPRF, S100A2, TGFB2). The blue one uncovered genes involved in cell division and inflammatory response (CD97, MAD2L1, ZFP106, CDKN2C, LOC514364, NOP14, PCBD1, LOC100139798, AP1S1, EDN1, IL1B, ANXA11). Our study identified some mechanisms (represented by gene modules) that have changed in cows in early response to mastitis infection. Further analysis are being carried out, based on these results, to advance the understanding of animals response to the disease, which can lead to identify the candidate genes that could be used in breeding programs.X-MEETING 2011

Identificação de mecanismos envolvidos na resposta de bovinos ao carrapato Rhipicephalus microplus.

O objetivo desse trabalho foi identificar grupos de genes envolvidos na resposta de bovinos à infestação artificial com o carrapato Rhipicephalus microplus, por meio da construção de redes gênicas. Dados de um experimento com microarranjos, provenientes da hibridização de amostras de pele de fêmeas cruzadas Senepol x Nelore, Angus x Nelore e Nelore, obtidas antes (A) e (D) após a infestação artificial com o carrapato, foram analisados por meio de uma metodologia de construção de redes baseada em co-expressão gênica (WGCNA). Os dados foram pré-processados usando os pacotes affy e gcrma do R/Bioconductor e as redes de co-expressão identificadas separadamente para cada grupo (A e D), pelo pacote R/WGCNA. As redes foram comparadas e os módulos não conservados entre os dois grupos foram identificados a partir de um teste de correlação dos valores de conectividade. Nossa análise identificou 8 módulos de genes co-expressos, sendo um deles (6) não conservado entre os grupos. O modulo 6 (n=85 genes) mostrou-se enriquecido para o processo biológico Proteólise, sugerindo o envolvimento desse processo e dos genes identificados (ADAMTS4, CASP4, C3, CFB, PRSS22 e SPCS3) na resposta dos animais à infestação

Identificação de mecanismos envolvidos na resposta de bovinos ao carrapato Rhipicephalus microplus.

O objetivo desse trabalho foi identificar grupos de genes envolvidos na resposta de bovinos à infestação artificial com o carrapato Rhipicephalus microplus, por meio da construção de redes gênicas. Dados de um experimento com microarranjos, provenientes da hibridização de amostras de pele de fêmeas cruzadas Senepol x Nelore, Angus x Nelore e Nelore, obtidas antes (A) e (D) após a infestação artificial com o carrapato, foram analisados por meio de uma metodologia de construção de redes baseada em co-expressão gênica (WGCNA). Os dados foram pré-processados usando os pacotes affy e gcrma do R/Bioconductor e as redes de co-expressão identificadas separadamente para cada grupo (A e D), pelo pacote R/WGCNA. As redes foram comparadas e os módulos não conservados entre os dois grupos foram identificados a partir de um teste de correlação dos valores de conectividade. Nossa análise identificou 8 módulos de genes co-expressos, sendo um deles (6) não conservado entre os grupos. O modulo 6 (n=85 genes) mostrou-se enrique ido para o processo biológico Proteólise, sugerindo o envolvimento desse processo e dos genes identificados (ADAMTS4, CASP4, C3, CFB, PRSS22 e SPCS3) na resposta dos animais à infestação

A gene expression atlas of Vellozia nivea, a desiccation-tolerant species from the Brazilian campos rupestres.

Velloziaceae are an angiosperm family that contains the most desiccation-tolerant species (approximately 200 out of 270 species). More than 80% of the Velloziaceae species occur in South America, where the greatest morphological diversity is also found. The genus Vellozia comprises both desiccation-tolerant and non-desiccation-tolerant species, offering an excellent model for studying the evolution of desiccation- and drought-tolerance traits on plant genomes. To date, only limited genomic or transcript sequences are available for Velloziaceaespecies. Here we present a Vellozia nivea gene expression atlas across different plant organs and tissues, including flower, developing seeds, root, leaf, stem and seedling. Vellozia nivea is a desiccation-tolerant species, endemic to the Brazilian campos rupestres (rupestrian grasslands) and highly adapted to their extreme conditions. A total of 180.67 Gb of raw data were generated, and of these, 152.79 Gb were subjected to downstream analysis after quality control (QC). Vellozia niveade novotranscriptome assembly was performed with the Trinity bioinformatics tool, resulting in 684.615 contigs. After filtering contaminated sequence contigs from bacteria and fungi and removal of contigs with less than 10 sequence reads associated with the initial assembly, the transcriptome resulted in 195.512 remaining sequences. A GO enrichment analysis was performed on tissue‐specific transcripts. The Vellozia nivea transcriptome should be a useful resource for genome annotation and gene function discovery studies.PE1028

A Mechanistic View of the Role of E3 in Sumoylation

Sumoylation, the covalent attachment of SUMO (Small Ubiquitin-Like Modifier) to proteins, differs from other Ubl (Ubiquitin-like) pathways. In sumoylation, E2 ligase Ubc9 can function without E3 enzymes, albeit with lower reaction efficiency. Here, we study the mechanism through which E3 ligase RanBP2 triggers target recognition and catalysis by E2 Ubc9. Two mechanisms were proposed for sumoylation. While in both the first step involves Ubc9 conjugation to SUMO, the subsequent sequence of events differs: in the first E2-SUMO forms a complex with the target and E3, followed by SUMO transfer to the target. In the second, Ubc9-SUMO binds to the target and facilitates SUMO transfer without E3. Using dynamic correlations obtained from explicit solvent molecular dynamic simulations we illustrate the key roles played by allostery in both mechanisms. Pre-existence of conformational states explains the experimental observations that sumoylation can occur without E3, even though at a reduced rate. Furthermore, we propose a mechanism for enhancement of sumoylation by E3. Analysis of the conformational ensembles of the complex of E2 conjugated to SUMO illustrates that the E2 enzyme is already largely pre-organized for target binding and catalysis; E3 binding shifts the equilibrium and enhances these pre-existing populations. We further observe that E3 binding regulates allosterically the key residues in E2, Ubc9 Asp100/Lys101 E2, for the target recognition

Cluster Lenses

Clusters of galaxies are the most recently assembled, massive, bound structures in the Universe. As predicted by General Relativity, given their masses, clusters strongly deform space-time in their vicinity. Clusters act as some of the most powerful gravitational lenses in the Universe. Light rays traversing through clusters from distant sources are hence deflected, and the resulting images of these distant objects therefore appear distorted and magnified. Lensing by clusters occurs in two regimes, each with unique observational signatures. The strong lensing regime is characterized by effects readily seen by eye, namely, the production of giant arcs, multiple-images, and arclets. The weak lensing regime is characterized by small deformations in the shapes of background galaxies only detectable statistically. Cluster lenses have been exploited successfully to address several important current questions in cosmology: (i) the study of the lens(es) - understanding cluster mass distributions and issues pertaining to cluster formation and evolution, as well as constraining the nature of dark matter; (ii) the study of the lensed objects - probing the properties of the background lensed galaxy population - which is statistically at higher redshifts and of lower intrinsic luminosity thus enabling the probing of galaxy formation at the earliest times right up to the Dark Ages; and (iii) the study of the geometry of the Universe - as the strength of lensing depends on the ratios of angular diameter distances between the lens, source and observer, lens deflections are sensitive to the value of cosmological parameters and offer a powerful geometric tool to probe Dark Energy. In this review, we present the basics of cluster lensing and provide a current status report of the field.Comment: About 120 pages - Published in Open Access at: http://www.springerlink.com/content/j183018170485723/ . arXiv admin note: text overlap with arXiv:astro-ph/0504478 and arXiv:1003.3674 by other author

Cardiac magnetic resonance imaging-indeterminate/negative cardiac sarcoidosis revealed by 18F-fluorodeoxyglucose-positron emission tomography: two case reports and a review of the literature

Abstract Background Sarcoidosis is an inflammatory disorder of immune dysregulation characterized by non-caseating granulomas that can affect any organ. Cardiac sarcoidosis is an under-recognized entity that has a heterogeneous presentation and may occur independently or with any severity of systemic disease. Diagnosing cardiac sarcoidosis remains problematic with endomyocardial biopsies associated with a high risk of complications. Several diagnostic algorithms are currently available that rely on histopathology or clinical and radiological measures. The dominant mode of diagnostic imaging to date for cardiac sarcoidosis has been cardiac magnetic resonance imaging with gadolinium enhancement. Case presentations We report the cases of two adult patients: case 1, a 50-year-old white man who presented with severe congestive cardiac failure; and case 2, a 37-year-old white woman who presented with complete heart block. Both patients had a background of untreated pulmonary sarcoidosis. Cardiac magnetic resonance imaging did not show evidence of sarcoidosis in either patient and both proceeded to 18F-fluorodeoxyglucose-positron emission tomography scans that were highly suggestive of cardiac sarcoidosis. Both patients were systemically immunosuppressed with orally administered prednisone and methotrexate and had subsequent improvement by clinical and nuclear medicine imaging measures. Conclusions Current consensus guidelines recommend all patients with sarcoidosis undergo screening for occult cardiac disease, with thorough history and examination, electrocardiogram, and transthoracic echocardiogram. If any abnormalities are detected, advanced cardiac imaging should follow. While cardiac magnetic resonance imaging identifies the majority of cardiac sarcoidosis, early disease may not be detected. These cases demonstrate 18F-fluorodeoxyglucose-positron emission tomography is warranted following an indeterminate or normal cardiac magnetic resonance imaging if clinical suspicion remains high. Unidentified and untreated cardiac sarcoidosis risks significant morbidity and mortality, but early detection can facilitate disease-modifying immunosuppression and cardiac-specific interventions

Role of PACAP and VIP Signalling in Regulation of Chondrogenesis and Osteogenesis

Pituitary adenylate cyclase activating polypeptide (PACAP) and vasoactive intestinal peptide (VIP) are multifunctional proteins that can regulate diverse physiological processes. These are also regarded as neurotrophic and anti-inflammatory substances in the CNS, and PACAP is reported to prevent harmful effects of oxidative stress. In the last decade more and more data accumulated on the similar function of PACAP in various tissues, but its cartilage- and bone-related presence and functions have not been widely investigated yet. In this summary we plan to verify the presence and function of PACAP and VIP signalling tool kit during cartilage differentiation and bone formation. We give evidence about the protective function of PACAP in cartilage regeneration with oxidative or mechanically stress and also with the modulation of PACAP signalling in vitro in osteogenic cells. Our observations imply the therapeutic perspective that PACAP might be applicable as a natural agent exerting protecting effect during joint inflammation and/or may promote cartilage regeneration during degenerative diseases of articular cartilage

Structural, thermal and dissolution properties of MgO- and CaO-containing borophosphate glasses: effect of Fe2O3 addition

This paper investigated manufacture of high-durability phosphate glass fibres for biomedical applications. Five different borophosphate glass formulations in the systems of 45P2O5–5B2O3–5Na2O–(29 − x)CaO–16MgO–(x)Fe2O3 and 45P2O5–5B2O3–5Na2O–24CaO–(21 − x)MgO–(x)Fe2O3 where x = 5, 8 and 11 mol% were produced via melt quenching. The compositions and amorphous nature of the glasses were confirmed by ICP-MS and XRD, respectively. FTIR results indicated depolymerisation of the phosphate chains with a decrease in Q2 units with increasing Fe2O3 content. DSC analyses showed an increase in Tg by ~5 °C with an increment of 3 mol% in Fe2O3 content. The thermal properties were also used to calculate processing window (i.e. Tc,ons—Tg) and another parameter, Kgl, to determine the suitability for fibre drawing directly from melt, which equals (Tc,ons—Tg)/(Tl—Tc,ons). The degradation study conducted in PBS solution at 37 °C showed a decrease of 25–47% in degradation rate with increasing Fe2O3 content. This confirmed that the chemical durability of the glasses had increased, which was suggested to be due to Fe2O3 addition. Furthermore, the density measured via Archimedes method revealed a linear increase with increasing Fe2O3 content