12 results on '"Salomon CE"'
Search Results
2. Radarsat-1 image processing for regional-scale geological mapping with mining vocation under dense vegetation and equatorial climate environment, Southwestern Cameroon
- Author
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Salomon Cesar Nguemhe Fils, Carrol Hedwige Bekele Mongo, David Guimolaire Nkouathio, Mumbfu Ernestine Mimba, Joachim Etouna, Philippe Njandjock Nouck, and Brunot Nyeck
- Subjects
Geodesy ,QB275-343 - Abstract
The potential of Radarsat-1 beam mode Synthetic Aperture Radar (SAR) data processing for geological investigation in an equatorial environment has been evaluated. This approach used textural analysis based on Grey Level Co-occurrence Matrix (GLCM) on our image, followed by Principal Component Analysis (PCA) performed on eight normalized co-occurrence indices created (mean, variance, homogeneity, contrast, dissimilarity, entropy, second moment and correlation) and directional filters for lithological discriminations and lineament investigations. Red-Green-Blue (RGB) color-composite was applied to three of the indices, the mean, variance and homogeneity, highlighting the morphostructure of the study area and facilitate lithology discrimination. The PC1 band was multiplied by itself (as PC1 × PC1 image) to enhance the information contained in this neo-canal and to reduce noise during filtering. Directional filters were then applied to the PC1 × PC1 image at 0°, 45°, 90° and 135° directions and the structure lines were extracted manually in a GIS software. From the results obtained, color-composite produced image map containing lithological units easily identified formations such as continental and coastal deposits, sedimentary stack, micaschists, garnet micaschists, micaceous quartzites, charnockitic orthogneisses, and coincided with those already existing on published geological map from Maurizot et al. (1986) and non-published geological map after IRGM geological field campaign. A total of 572 lineaments features (fractures and major faults) were identified on the filtered images and mapped. Major structures (faults) were considered as those clearly identified in the four directions while minor structures (fractures) were those observed in at least two directions. They are oriented in one of the two main directions: NE-SW (N040–N060) and NNW-SSE (N345–N360). The lineament result showed those that already existed on the reference maps and the newly updated lineaments. Spatial relationships between mapped lineaments and areas of current and historical mining exploration were examined by overall lineament density. GPS points of gold indices existing in the area correlate with areas of high lineament density particularly around the Ngovayang massif within the Paleoproterozoic Nyong unit. This study stresses the usefulness of remote sensing data and methods in field campaign, improvement of published geological maps and mining prospecting in areas with an equatorial climate. Keywords: RADARSAT1, GLCM, PCA, Directional filters, Geological investigation, Equatorial environment
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- 2018
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3. A Collaborative Change Detection Approach on Multi-Sensor Spatial Imagery for Desert Wetland Monitoring after a Flash Flood in Southern Morocco
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Sofia Hakdaoui, Anas Emran, Biswajeet Pradhan, Chang-Wook Lee, and Salomon Cesar Nguemhe Fils
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categorical processing ,collaborative change detection ,remote sensing ,GIS ,wet land monitoring ,Morocco ,Science - Abstract
This study aims to present a technique that combines multi-sensor spatial data to monitor wetland areas after a flash-flood event in a Saharan arid region. To extract the most efficient information, seven satellite images (radar and optical) taken before and after the event were used. To achieve the objectives, this study used Sentinel-1 data to discriminate water body and soil roughness, and optical data to monitor the soil moisture after the event. The proposed method combines two approaches: one based on spectral processing, and the other based on categorical processing. The first step was to extract four spectral indices and utilize change vector analysis on multispectral diachronic images from three MSI Sentinel-2 images and two Landsat-8 OLI images acquired before and after the event. The second step was performed using pattern classification techniques, namely, linear classifiers based on support vector machines (SVM) with Gaussian kernels. The results of these two approaches were fused to generate a collaborative wetland change map. The application of co-registration and supervised classification based on textural and intensity information from Radar Sentinel-1 images taken before and after the event completes this work. The results obtained demonstrate the importance of the complementarity of multi-sensor images and a multi-approach methodology to better monitor changes to a wetland area after a flash-flood disaster.
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- 2019
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4. Diverse subterranean fungi of an underground iron ore mine.
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Held BW, Salomon CE, and Blanchette RA
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- Wastewater chemistry, Fungi isolation & purification, Iron, Mining
- Abstract
Mines and caves are unusual ecosystems containing unique fungi and are greatly understudied compared to other environments. The Soudan Mine in Tower, MN, an iron ore mine that closed in 1963 after operating for 80 years, was sampled to explore fungal diversity and to investigate taxa that tolerate heavy metals for potential bioprocessing technologies or as sources of bioactive molecules for drug discovery and possible biocontrol for white-nose syndrome (WNS) of bats. The mine is 714 m deep, has 18 levels and contains large quantities of wooden timbers, in contrast to many other oligotrophic subterranean environments. Fungi were cultured from samples and the ITS region was sequenced for identification and phylogenetic analysis. Results show Ascomycota are the dominant fungi followed by Basidiomycota and Mucoromycota. Out of 164 identified taxa, 108 belong to the Ascomycota and 26 and 31 to Basidiomycota and Mucoromycota, respectively. There are also 46 taxa that do not match (<97% BLAST GenBank identity) sequenced fungal species. Examples of the most commonly isolated Ascomycota include Scytalidium sp., Mariannaea comptospora, Hypocrea pachybasidioides, Oidiodendron griseum and Pochonia bulbillosa; Basidiomycota include Postia sp., Sistotrema brinkmannii, Calocera sp., Amylocorticiellum sp.; Mucoromycota include Mortierella parvispora, M. gamsii, M. hyaline, M. basiparvispora and Mortierella sp. Unusual growth forms were also found including large quantities of black rhizomorphs of Armillaria sinapina and white mycelial cords of Postia sp. mycelium, as well as Pseudogymnoascus species growing over large areas of mine walls and ceiling. The mine environment is a relatively extreme environment for fungi, with the presence of high levels of heavy metals, complete darkness and poor nutrient availability. Several genera are similar to those isolated in other extreme environments but phylogenetic analyses show differences in species between these environments. Results indicate this subterranean environment hosts a wide diversity of fungi, many of them not found in above ground environments., Competing Interests: The authors have declared that no competing interests exist.
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- 2020
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5. Discovery of Antifungal and Biofilm Preventative Compounds from Mycelial Cultures of a Unique North American Hericium sp. Fungus.
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Song X, Gaascht F, Schmidt-Dannert C, and Salomon CE
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- Agaricales growth & development, Biofilms, Mycelium growth & development, Agaricales chemistry, Antifungal Agents chemistry, Antifungal Agents pharmacology, Candida albicans growth & development, Mycelium chemistry
- Abstract
Edible mushrooms are an important source of nutraceuticals and for the discovery of bioactive metabolites as pharmaceuticals. In this work, the OSMAC (One Strain, Many Active Compounds) approach was used to isolate two new compounds ( 1 and 2 ) along with seven known compounds ( 3 - 9 ) from a mycelial culture of a unique North American edible mushroom Hericium sp. The fruiting body was collected in Marine on St. Croix, Minnesota (USA), and mycelial cultures were grown on four different solid and liquid media. Extracts from the mycelial cultures were screened for antimicrobial activity and only the extract from the Cheerios substrate culture exhibited antifungal activity. Bioassay guided fractionation and HPLC analysis were used to isolate nine pure compounds and the structures of the known compounds were established by analysis of the NMR and mass spectrometry data and comparison to published reports. Compound 1 is a new erinacerin alkaloid and 2 is an aldehyde derivative of 4-hydroxy chroman. Four chlorinated orcinol derivatives ( 3 - 6 ), a pyran ( 7 ), erinaceolactone ( 8 ), and erinacine ( 9 ) were identified. Compound 4 showed antifungal activity against C. albicans and C. neoformans (MIC = 31.3-62.5 μg/mL, respectively). Compound 4 also inhibited biofilm formation of C. albicans and C. neoformans at 7.8 μg/mL. These results suggest that mycelial cultures of edible fungi may provide useful, bioactive compounds.
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- 2020
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6. Resource capture and competitive ability of non-pathogenic Pseudogymnoascus spp. and P. destructans, the cause of white-nose syndrome in bats.
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Wilson MB, Held BW, Freiborg AH, Blanchette RA, and Salomon CE
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- Animals, Antifungal Agents pharmacology, Chiroptera physiology, DNA, Fungal genetics, Hibernation, Nose microbiology, Phylogeny, Saccharomycetales drug effects, Saccharomycetales growth & development, Saccharomycetales isolation & purification, Chiroptera microbiology, Mycoses veterinary, Saccharomycetales classification
- Abstract
White-nose syndrome (WNS) is a devastating fungal disease that has been causing the mass mortality of hibernating bats in North America since 2006 and is caused by the psychrophilic dermatophyte Pseudogymnoascus destructans. Infected bats shed conidia into hibernaculum sediments and surfaces, but it is unknown if P. destructans can form stable, reproductive populations outside its bat hosts. Previous studies have found non-pathogenic Pseudogymnoascus in bat hibernacula, and these fungi may provide insight into the natural history of P. destructans. We compared the relatedness, resource capture, and competitive ability of non-pathogenic Pseudogymnoascus isolates with P. destructans to determine if they have similar adaptations for survival in hibernacula sediment. All non-pathogenic Pseudogymnoascus isolates grew faster, utilized a broader range of substrates with higher efficiency, and were generally more resistant to antifungals compared to P. destructans. All isolates also showed the ability to displace P. destructans in co-culture assays, but only some produced extractible antifungal metabolites. These results suggest that P. destructans would perform poorly in the same environmental niche as non-pathogenic Pseudogymnoascus, and must have an alternative saprophytic survival strategy if it establishes active populations in hibernaculum sediment and non-host surfaces.
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- 2017
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7. Complete Genome Sequence of Streptomyces albus SM254, a Potent Antagonist of Bat White-Nose Syndrome Pathogen Pseudogymnoascus destructans.
- Author
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Badalamenti JP, Erickson JD, and Salomon CE
- Abstract
We sequenced and annotated the complete 7,170,504-bp genome of a novel secondary metabolite-producingStreptomycesstrain,Streptomyces albusSM254, isolated from copper-rich subsurface fluids at ~220-m depth within the Soudan Iron Mine (Soudan, MN, USA)., (Copyright © 2016 Badalamenti et al.)
- Published
- 2016
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8. Growth inhibition and apoptosis in cancer cells induced by polyphenolic compounds of Acacia hydaspica: Involvement of multiple signal transduction pathways.
- Author
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Afsar T, Trembley JH, Salomon CE, Razak S, Khan MR, and Ahmed K
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- Blotting, Western, Catechin analogs & derivatives, Catechin chemistry, Catechin pharmacology, Cell Line, Tumor, Cell Survival drug effects, Gallic Acid analogs & derivatives, Gallic Acid chemistry, Gallic Acid pharmacology, Humans, Inhibitor of Apoptosis Proteins metabolism, Microscopy, Fluorescence, Molecular Structure, NF-kappa B metabolism, Neoplasms metabolism, Neoplasms pathology, Phosphatidylinositol 3-Kinases metabolism, Polyphenols chemistry, Proto-Oncogene Proteins c-akt metabolism, Proto-Oncogene Proteins c-bcl-2 metabolism, Survivin, X-Linked Inhibitor of Apoptosis Protein metabolism, bcl-X Protein metabolism, Acacia chemistry, Apoptosis drug effects, Cell Proliferation drug effects, Polyphenols pharmacology, Signal Transduction drug effects
- Abstract
Acacia hydaspica R. Parker is known for its medicinal uses in multiple ailments. In this study, we performed bioassay-guided fractionation of cytotoxic compounds from A. hydaspica and investigated their effects on growth and signaling activity in prostate and breast cancer cell lines. Four active polyphenolic compounds were identified as 7-O-galloyl catechin (GC), catechin (C), methyl gallate (MG), and catechin-3-O-gallate (CG). The four compounds inhibited prostate cancer PC-3 cell growth in a dose-dependent manner, whereas CG and MG inhibited breast cancer MDA-MB-231 cell growth. All tested compounds inhibited cell survival and colony growth in both cell lines, and there was evidence of chromatin condensation, cell shrinkage and apoptotic bodies. Further, acridine orange, ethidium bromide, propidium iodide and DAPI staining demonstrated that cell death occurred partly via apoptosis in both PC-3 and MDA-MB-231 cells. In PC-3 cells treatment repressed the expression of anti-apoptotic molecules Bcl-2, Bcl-xL and survivin, coupled with down-regulation of signaling pathways AKT, NFκB, ERK1/2 and JAK/STAT. In MDA-MB-231 cells, treatment induced reduction of CK2α, Bcl-xL, survivin and xIAP protein expression along with suppression of NFκB, JAK/STAT and PI3K pathways. Our findings suggest that certain polyphenolic compounds derived from A. hydaspica may be promising chemopreventive/therapeutic candidates against cancer.
- Published
- 2016
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9. Ultra-High-Throughput Screening of Natural Product Extracts to Identify Proapoptotic Inhibitors of Bcl-2 Family Proteins.
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Hassig CA, Zeng FY, Kung P, Kiankarimi M, Kim S, Diaz PW, Zhai D, Welsh K, Morshedian S, Su Y, O'Keefe B, Newman DJ, Rusman Y, Kaur H, Salomon CE, Brown SG, Baire B, Michel AR, Hoye TR, Francis S, Georg GI, Walters MA, Divlianska DB, Roth GP, Wright AE, and Reed JC
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- Caco-2 Cells, Caspase 3 metabolism, Caspase 7 metabolism, Drug Screening Assays, Antitumor methods, Fluorescence Polarization methods, High-Throughput Screening Assays instrumentation, Humans, Miniaturization, Molecular Targeted Therapy methods, Mycotoxins isolation & purification, Mycotoxins pharmacology, Solid Phase Extraction, bcl-X Protein antagonists & inhibitors, Biological Products chemistry, High-Throughput Screening Assays methods, Proto-Oncogene Proteins c-bcl-2 antagonists & inhibitors
- Abstract
Antiapoptotic Bcl-2 family proteins are validated cancer targets composed of six related proteins. From a drug discovery perspective, these are challenging targets that exert their cellular functions through protein-protein interactions (PPIs). Although several isoform-selective inhibitors have been developed using structure-based design or high-throughput screening (HTS) of synthetic chemical libraries, no large-scale screen of natural product collections has been reported. A competitive displacement fluorescence polarization (FP) screen of nearly 150,000 natural product extracts was conducted against all six antiapoptotic Bcl-2 family proteins using fluorochrome-conjugated peptide ligands that mimic functionally relevant PPIs. The screens were conducted in 1536-well format and displayed satisfactory overall HTS statistics, with Z'-factor values ranging from 0.72 to 0.83 and a hit confirmation rate between 16% and 64%. Confirmed active extracts were orthogonally tested in a luminescent assay for caspase-3/7 activation in tumor cells. Active extracts were resupplied, and effort toward the isolation of pure active components was initiated through iterative bioassay-guided fractionation. Several previously described altertoxins were isolated from a microbial source, and the pure compounds demonstrate activity in both Bcl-2 FP and caspase cellular assays. The studies demonstrate the feasibility of ultra-high-throughput screening using natural product sources and highlight some of the challenges associated with this approach., (© 2014 Society for Laboratory Automation and Screening.)
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- 2014
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10. Subinhibitory antibiotic concentrations mediate nutrient use and competition among soil streptomyces.
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Vaz Jauri P, Bakker MG, Salomon CE, and Kinkel LL
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- Dose-Response Relationship, Drug, Streptomyces isolation & purification, Streptomyces metabolism, Streptomyces physiology, Anti-Bacterial Agents pharmacology, Soil Microbiology, Streptomyces drug effects
- Abstract
Though traditionally perceived as weapons, antibiotics are also hypothesized to act as microbial signals in natural habitats. However, while subinhibitory concentrations of antibiotics (SICA) are known to shift bacterial gene expression, specific hypotheses as to how SICA influence the ecology of natural populations are scarce. We explored whether antibiotic 'signals', or SICA, have the potential to alter nutrient utilization, niche overlap, and competitive species interactions among Streptomyces populations in soil. For nine diverse Streptomyces isolates, we evaluated nutrient utilization patterns on 95 different nutrient sources in the presence and absence of subinhibitory concentrations of five antibiotics. There were significant changes in nutrient use among Streptomyces isolates, including both increases and decreases in the capacity to use individual nutrients in the presence vs. in the absence of SICA. Isolates varied in their responses to SICA and antibiotics varied in their effects on isolates. Furthermore, for some isolate-isolate-antibiotic combinations, competition-free growth (growth for an isolate on all nutrients that were not utilized by a competing isolate), was increased in the presence of SICA, reducing the potential fitness cost of nutrient competition among those competitors. This suggests that antibiotics may provide a mechanism for bacteria to actively minimize niche overlap among competitors in soil. Thus, in contrast to antagonistic coevolutionary dynamics, antibiotics as signals may mediate coevolutionary displacement among coexisting Streptomyces, thereby hindering the emergence of antibiotic resistant phenotypes. These results contribute to our broad understanding of the ecology and evolutionary biology of antibiotics and microbial signals in nature.
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- 2013
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11. Pathogen variation and urea influence selection and success of Streptomyces mixtures in biological control.
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Otto-Hanson LK, Grabau Z, Rosen C, Salomon CE, and Kinkel LL
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- Anti-Bacterial Agents pharmacology, Biological Control Agents, Drug Resistance, Multiple, Bacterial drug effects, Host-Pathogen Interactions, Phenotype, Plant Diseases prevention & control, Plant Tubers drug effects, Plant Tubers microbiology, Solanum tuberosum drug effects, Streptomyces drug effects, Streptomyces isolation & purification, Streptomyces pathogenicity, Antibiosis drug effects, Plant Diseases microbiology, Soil Microbiology, Solanum tuberosum microbiology, Streptomyces physiology, Urea pharmacology
- Abstract
Success in biological control of plant diseases remains inconsistent in the field. A collection of well-characterized Streptomyces antagonists (n = 19 isolates) was tested for their capacities to inhibit pathogenic Streptomyces scabies (n = 15 isolates). There was significant variation among antagonists in ability to inhibit pathogen isolates and among pathogens in their susceptibility to inhibition. Only one antagonist could inhibit all pathogens, and antagonist-pathogen interactions were highly specific, highlighting the limitations of single-strain inoculum in biological control. However, the collection of pathogens could be inhibited by several combinations of antagonists, suggesting the potential for successful antagonist mixtures. Urea generally increased effectiveness of antagonists at inhibiting pathogens in vitro (increased mean inhibition zones) but its specific effects varied among antagonist-pathogen combinations. In greenhouse trials, urea enhanced the effectiveness of antagonist mixtures relative to individual antagonists in controlling potato scab. Although antagonist mixtures were frequently antagonistic in the absence of urea, all n= 2 and n = 3 antagonist-isolate combinations were synergistic in the presence of urea. This work provides insights into the efficacy of single- versus multiple-strain inocula in biological control and on the potential for nutrients to influence mixture success.
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- 2013
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12. Total synthesis of narbonolide and biotransformation to pikromycin.
- Author
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Venkatraman L, Salomon CE, Sherman DH, and Fecik RA
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- Biotransformation, Chromatography, High Pressure Liquid, Macrolides chemistry, Molecular Structure, Sensitivity and Specificity, Stereoisomerism, Streptomyces chemistry, Streptomyces metabolism, Macrolides chemical synthesis, Macrolides metabolism
- Abstract
An improved total synthesis of narbonolide and its biotransformation to pikromycin is reported. This total synthesis utilized an intramolecular Nozaki-Hiyama-Kishi coupling that significantly improved macrocyclization yields (90-96%) and allowed for differentiation of the C3- and C5-oxidation states. A pikAI deletion mutant of Streptomyces venezuelae was used to biotransform synthetic narbonolide to pikromycin by glycosylation and oxidation in vivo. This integration of synthetic chemistry and engineered biotransformations holds great promise for the synthesis of novel macrolide analogues of biological interest.
- Published
- 2006
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