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Sample records for anaerobic filamentous fungus

  1. Transcriptional monitoring of steady state and effects of anaerobic phases in chemostat cultures of the filamentous fungus Trichoderma reesei

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    Penttilä Merja

    2006-10-01

    Full Text Available Abstract Background Chemostat cultures are commonly used in production of cellular material for systems-wide biological studies. We have used the novel TRAC (transcript analysis with aid of affinity capture method to study expression stability of approximately 30 process relevant marker genes in chemostat cultures of the filamentous fungus Trichoderma reesei and its transformant expressing laccase from Melanocarpus albomyces. Transcriptional responses caused by transient oxygen deprivations and production of foreign protein were also studied in T. reesei by TRAC. Results In cultures with good steady states, the expression of the marker genes varied less than 20% on average between sequential samples for at least 5 or 6 residence times. However, in a number of T. reesei cultures continuous flow did not result in a good steady state. Perturbations to the steady state were always evident at the transcriptional level, even when they were not measurable as changes in biomass or product concentrations. Both unintentional and intentional perturbations of the steady state demonstrated that a number of genes involved in growth, protein production and secretion are sensitive markers for culture disturbances. Exposure to anaerobic conditions caused strong responses at the level of gene expression, but surprisingly the cultures could regain their previous steady state quickly, even after 3 h O2 depletion. The main effect of producing M. albomyces laccase was down-regulation of the native cellulases compared with the host strain. Conclusion This study demonstrates the usefulness of transcriptional analysis by TRAC in ensuring the quality of chemostat cultures prior to costly and laborious genome-wide analysis. In addition TRAC was shown to be an efficient tool in studying gene expression dynamics in transient conditions.

  2. Nuclear flow in a filamentous fungus

    CERN Document Server

    Hickey, Patrick C; Read, Nick; Glass, N Louise; Roper, Marcus

    2012-01-01

    The syncytial cells of a filamentous fungus consist of a mass of growing, tube-like hyphae. Each extending tip is fed by a continuous flow of nuclei from the colony interior, pushed by a gradient in turgor pressure. The myco-fluidic flows of nuclei are complex and multidirectional, like traffic in a city. We map out the flows in a strain of the model filamentous fungus {\\it N. crassa} that has been transformed so that nuclei express either hH1-dsRed (a red fluorescent nuclear protein) or hH1-GFP (a green-fluorescent protein) and report our results in a fluid dynamics video.

  3. Carbon starvation in the filamentous fungus Aspergillus niger

    NARCIS (Netherlands)

    Nitsche, Benjamin Manuel

    2012-01-01

    This study investigated carbon starvation in the filamentous fungus Aspergillus niger during submerged cultivation in bioreactor batch cultures. The work described in this thesis can be discussed as follows: (I) Establishment of computational resources for omics data analysis and interpretation in c

  4. Directed evolution of a filamentous fungus for thermotolerance

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    Lyons Thomas J

    2009-08-01

    Full Text Available Abstract Background Filamentous fungi are the most widely used eukaryotic biocatalysts in industrial and chemical applications. Consequently, there is tremendous interest in methodology that can use the power of genetics to develop strains with improved performance. For example, Metarhizium anisopliae is a broad host range entomopathogenic fungus currently under intensive investigation as a biologically based alternative to chemical pesticides. However, it use is limited by the relatively low tolerance of this species to abiotic stresses such as heat, with most strains displaying little to no growth between 35–37°C. In this study, we used a newly developed automated continuous culture method called the Evolugator™, which takes advantage of a natural selection-adaptation strategy, to select for thermotolerant variants of M. anisopliae strain 2575 displaying robust growth at 37°C. Results Over a 4 month time course, 22 cycles of growth and dilution were used to select 2 thermotolerant variants of M. anisopliae. Both variants displayed robust growth at 36.5°C, whereas only one was able to grow at 37°C. Insect bioassays using Melanoplus sanguinipes (grasshoppers were also performed to determine if thermotolerant variants of M. anisopliae retained entomopathogenicity. Assays confirmed that thermotolerant variants were, indeed, entomopathogenic, albeit with complex alterations in virulence parameters such as lethal dose responses (LD50 and median survival times (ST50. Conclusion We report the experimental evolution of a filamentous fungus via the novel application of a powerful new continuous culture device. This is the first example of using continuous culture to select for complex phenotypes such as thermotolerance. Temperature adapted variants of the insect-pathogenic, filamentous fungus M. anisopliae were isolated and demonstrated to show vigorous growth at a temperature that is inhibitory for the parent strain. Insect virulence assays

  5. Microalgae harvesting via co-culture with filamentous fungus

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    Gultom, Sarman Oktovianus

    Microalgae harvesting is a labor- and energy-intensive process. For instance, classical harvesting technologies such as chemical addition and mechanical separation are economically prohibiting for biofuel production. Newer approaches to harvest microalgae have been developed in order to decrease costs. Among these new methods, fungal co-pelletization seems to be a promising technology. By co-culturing filamentous fungi with microalgae, it is possible to form pellets, which can easily be separated. In this study, different parameters for the cultivation of filamentous fungus (Aspergillus niger) and microalgae (Chlorella vulgaris) to efficiently form cell pellets were evaluated under heterotrophic and phototrophic conditions, including organic carbon source (glucose, glycerol and sodium acetate) concentration, pH, initial concentration of fungal spores, initial concentration of microalgal cells, concentration of ionic strength (Calcium and Magnesium) and concentration of salinity (NaCl). In addition, zeta-potential measurements were carried out in order to get a better understanding of the mechanism of attraction. It was found that 2 g/L of glucose, a fungus to microalgae ratio of 1:300, and uncontrolled pH (around 7) are the best culturing conditions for co-pelletization. Under these conditions, it was possible to achieve a high harvesting performance (>90%). In addition, it was observed that most pellets formed in the co-culture were spherical with an average diameter of 3.5 mm and in concentrations of about 5 pellets per mL of culture media. Under phototrophic conditions, co-pelletization required the addition of glucose as organic carbon source to sustain the growth of fungi and to allow the harvesting of microalgae. Zeta-potential measurements indicated that (i) both microalgae and fungi have low zeta-potential values regardless of the pH on the bulk (i.e. <-10 mV) (ii) fungi can have a positive electric charge at low pH (ie. pH=3). These values suggest that it

  6. Pulmonary echinococcal cyst with a filamentous fungus co-infection.

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    Pandey, P; Dixit, A K; Tanwar, A; Mahajan, N C

    2013-09-01

    Fungal infections are known to colonize the pre-existing lung cavities formed as a result of diseases like tuberculosis, sarcoidosis, bronchiectasis and cavitatary neoplasia, mostly encountered in immunocompromised patients. Pulmonary echinococcal cysts have been reported coexistent with cryptococcosis and other saprophytic mycosis, but the coexistence of aspergillosis and echinococcal cyst is extremely rare and occasionally been reported in English literature. Active invasion and proliferation of the fungi in the laminated ectocyst of the echinococcal cyst is very unusual. We report a case of 60 years old immunocompetent female, presented with cough, chest pain and shortness of breath. The chest X-ray showed a large thick walled cavity in the lower and mid zone of right lung with positive water lily sign. Surgical enucleation of the echinococcal cyst revealed aspergilloma involving the cavity with massive invasion of laminated ectocyst by filamentous fungus, morphologically resembling an Aspergillus species and was further treated with Itraconazole for 3 months. This unique coexistence of active pulmonary echinococcosis and aspergillosis is being reported because of its rarity and clinical importance for its management.

  7. Physiological evaluation of the filamentous fungus Trichoderma reesei in production processes by marker gene expression analysis

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    Penttilä Merja

    2007-05-01

    Full Text Available Abstract Background Biologically relevant molecular markers can be used in evaluation of the physiological state of an organism in biotechnical processes. We monitored at high frequency the expression of 34 marker genes in batch, fed-batch and continuous cultures of the filamentous fungus Trichoderma reesei by the transcriptional analysis method TRAC (TRanscript analysis with the aid of Affinity Capture. Expression of specific genes was normalised either with respect to biomass or to overall polyA RNA concentration. Expressional variation of the genes involved in various process relevant cellular functions, such as protein production, growth and stress responses, was related to process parameters such as specific growth and production rates and substrate and dissolved oxygen concentrations. Results Gene expression of secreted cellulases and recombinant Melanocarpus albomyces laccase predicted the trends in the corresponding extracellular enzyme production rates and was highest in a narrow "physiological window" in the specific growth rate (μ range of 0.03 – 0.05 h-1. Expression of ribosomal protein mRNAs was consistent with the changes in μ. Nine starvation-related genes were found as potential markers for detection of insufficient substrate feed for maintaining optimal protein production. For two genes induced in anaerobic conditions, increasing transcript levels were measured as dissolved oxygen decreased. Conclusion The data obtained by TRAC supported the usefulness of focused and intensive transcriptional analysis in monitoring of biotechnical processes providing thus tools for process optimisation purposes.

  8. Solubilization of diabase and phonolite dust by filamentous fungus

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    Juliana Andréia Vrba Brandão

    2014-10-01

    Full Text Available The objective of this study was to evaluate the effect of the fungus Aspergillus niger strain CCT4355 in the release of nutrients contained in two types of rock powder (diabase and phonolite by means of in vitro solubilization trials. The experimental design was completely randomized in a 5 x 4 factorial design with three replications. It was evaluated five treatments (phonolite dust + culture medium; phonolite dust + fungus + culture medium; diabase powder + culture medium; diabase powder + fungus + culture medium and fungus + culture medium and four sampling dates (0, 10, 20 and 30 days. Rock dust (0.4% w/v was added to 125 mL Erlenmeyer flasks containing 50 mL of liquid culture medium adapted to A. niger. The flasks were incubated at 30°C for 30 days, and analysis of pH (in water, titratable acidity, and concentrations of soluble potassium, calcium, magnesium, zinc, iron and manganese were made. The fungus A. niger was able to produce organic acids that solubilized ions. This result indicates its potential to alter minerals contained in rock dust, with the ability to interact in different ways with the nutrients. A significant increase in the amount of K was found in the treatment with phonolite dust in the presence of the fungus. The strain CCT4355 of A. niger can solubilize minerals contained in these rocks dust.

  9. Aspiperidine oxide, a piperidine N-oxide from the filamentous fungus Aspergillus indologenus

    DEFF Research Database (Denmark)

    Petersen, Lene Maj; Kildgaard, Sara; Jaspars, Marcel;

    2015-01-01

    A novel secondary metabolite, aspiperidine oxide, was isolated from the filamentous fungus, Aspergillus indologenus. The structure of aspiperidine oxide was determined from extensive 1D and 2D NMR spectroscopic analysis supported by high-resolution mass spectrometry. The structure revealed a rare...

  10. Solubilization of animal bonechar by a filamentous fungus employed in solid state fermentation

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    Nikolay, Vassilev; Medina, A.; Gilberto, Mendes; Antonia, Galvez; Vanessa, Martos; Maria, Vassileva

    2013-01-01

    Abstract Experts are concerned by the scarcity of rock phosphate and the vulnerability of the modern agricultural systems which is highly dependent on the existing fertilizer industry based exclusively of this natural, finite, non-renewable resource. In this work, the filamentous fungus Aspergillus

  11. Light-mediated control of gene expression in filamentous fungus Trichoderma reesei.

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    Wang, Wei; Shi, Xiang-Yu; Wei, Dong-Zhi

    2014-08-01

    We developed a light-mediated system based on synthetic light-switchable transactivators. The transactivators bind promoter upon blue-light exposure and rapidly initiate transcription of target transgenes in filamentous fungus Trichoderma reesei. Light is inexpensive to apply, easily delivered, and instantly removed, and thus has significant advantages over chemical inducers.

  12. The response of filamentous fungus Rhizopus nigricans to flavonoids.

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    Slana, Marko; Zigon, Dušan; Makovec, Tomaž; Lenasi, Helena

    2011-08-01

    The saprophytic fungus Rhizopus nigricans constitutes a serious problem when thriving on gathered crops. The identification of any compounds, especially natural ones, that inhibit fungal growth, may therefore be important. During its life cycle, Rhizopus nigricans encounters many compounds, among them the flavonoids, plant secondary metabolites that are involved in plant defense against pathogenic microorganisms. Although not being a plant pathogen, Rhizopus nigricans may interact with these compounds in the same way as plant pathogens--in response to the fungitoxic effect of flavonoids the fungi transform them into less toxic metabolites. We have studied the interaction of R. nigricans with some flavonoids. Inhibition of hyphal spreading (from 3% to 100%) was observed by 300 μM flavones, flavanones and isoflavones, irrespective of their basic structure, oxidized or reduced C-ring, and orientation of the B-ring. However, a hydrophobic A-ring was important for the toxicity. R. nigricans transformed some of the flavonoids into glucosylated products. Recognition of substrates for glucosylating enzyme(s) did not correlate with their fungitoxic effect but depended exclusively on the presence of a free -OH group in the flavonoid A-ring and of a hydrophobic B-ring. Although the fungus produced glucosyltransferase constitutively, an additional amount of the enzyme was induced by the substrate flavonoid. Moreover, effective detoxification was shown to require the presence of glucose.

  13. Efficient genome editing in filamentous fungus Trichoderma reesei using the CRISPR/Cas9 system.

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    Liu, Rui; Chen, Ling; Jiang, Yanping; Zhou, Zhihua; Zou, Gen

    2015-01-01

    Filamentous fungi have wide applications in biotechnology. The CRISPR/Cas9 system is a powerful genome-editing method that facilitates genetic alterations of genomes in a variety of organisms. However, a genome-editing approach has not been reported in filamentous fungi. Here, we demonstrated the establishment of a CRISPR/Cas9 system in the filamentous fungus Trichoderma reesei by specific codon optimization and in vitro RNA transcription. It was shown that the CRISPR/Cas9 system was controllable and conditional through inducible Cas9 expression. This system generated site-specific mutations in target genes through efficient homologous recombination, even using short homology arms. This system also provided an applicable and promising approach to targeting multiple genes simultaneously. Our results illustrate that the CRISPR/Cas9 system is a powerful genome-manipulating tool for T. reesei and most likely for other filamentous fungal species, which may accelerate studies on functional genomics and strain improvement in these filamentous fungi.

  14. SnoRNAs from the filamentous fungus Neurospora crassa: structural, functional and evolutionary insights

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    Chen Chun-Long

    2009-11-01

    Full Text Available Abstract Background SnoRNAs represent an excellent model for studying the structural and functional evolution of small non-coding RNAs involved in the post-transcriptional modification machinery for rRNAs and snRNAs in eukaryotic cells. Identification of snoRNAs from Neurospora crassa, an important model organism playing key roles in the development of modern genetics, biochemistry and molecular biology will provide insights into the evolution of snoRNA genes in the fungus kingdom. Results Fifty five box C/D snoRNAs were identified and predicted to guide 71 2'-O-methylated sites including four sites on snRNAs and three sites on tRNAs. Additionally, twenty box H/ACA snoRNAs, which potentially guide 17 pseudouridylations on rRNAs, were also identified. Although not exhaustive, the study provides the first comprehensive list of two major families of snoRNAs from the filamentous fungus N. crassa. The independently transcribed strategy dominates in the expression of box H/ACA snoRNA genes, whereas most of the box C/D snoRNA genes are intron-encoded. This shows that different genomic organizations and expression modes have been adopted by the two major classes of snoRNA genes in N. crassa . Remarkably, five gene clusters represent an outstanding organization of box C/D snoRNA genes, which are well conserved among yeasts and multicellular fungi, implying their functional importance for the fungus cells. Interestingly, alternative splicing events were found in the expression of two polycistronic snoRNA gene hosts that resemble the UHG-like genes in mammals. Phylogenetic analysis further revealed that the extensive separation and recombination of two functional elements of snoRNA genes has occurred during fungus evolution. Conclusion This is the first genome-wide analysis of the filamentous fungus N. crassa snoRNAs that aids in understanding the differences between unicellular fungi and multicellular fungi. As compared with two yeasts, a more complex

  15. Unraveling the Secondary Metabolism of the Biotechnological Important Filamentous Fungus Trichoderma reesei ( Teleomorph Hypocrea jecorina)

    DEFF Research Database (Denmark)

    Jørgensen, Mikael Skaanning

    and they therefore constitute one of the most important sources for pharmaceuticals; including drugs for treatment of infections, for lowering of the cholesterol level in the bloodstream and for minimizing undesirable immune responses. The primary objective of this study was to gain more knowledge about the genetic......The filamentous fungus Trichoderma reesei (teleomorph Hypocrea jecorina) is one of the most important industrial production organisms, owing to its highly efficient (hemi-)cellulase synthesis and secretion machineries. These enzymes, which in nature allow the fungus to utilize energy bound...... mechanisms leading to biosynthesis of two of the most prominent types of secondary metabolites produced by T. reesei, polyketides and non-ribosomal peptides. Since the molecular tools for T. reesei are not as well-developed as for many other species, the study was initiated with creation of new genetic tools...

  16. Nickel oxide nanoparticles film produced by dead biomass of filamentous fungus

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    Salvadori, Marcia Regina; Nascimento, Cláudio Augusto Oller; Corrêa, Benedito

    2014-09-01

    The synthesis of nickel oxide nanoparticles in film form using dead biomass of the filamentous fungus Aspergillus aculeatus as reducing agent represents an environmentally friendly nanotechnological innovation. The optimal conditions and the capacity of dead biomass to uptake and produce nanoparticles were evaluated by analyzing the biosorption of nickel by the fungus. The structural characteristics of the film-forming nickel oxide nanoparticles were analyzed by scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), and atomic force microscopy (AFM). These techniques showed that the nickel oxide nanoparticles had a size of about 5.89 nm and were involved in a protein matrix which probably permitted their organization in film form. The production and uptake of nickel oxide nanoparticles organized in film form by dead fungal biomass bring us closer to sustainable strategies for the biosynthesis of metal oxide nanoparticles.

  17. What’s in the genome of a filamentous fungus? Analysis of the Neurospora genome sequence

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    Mannhaupt, Gertrud; Montrone, Corinna; Haase, Dirk; Mewes, H. Werner; Aign, Verena; Hoheisel, Jörg D.; Fartmann, Berthold; Nyakatura, Gerald; Kempken, Frank; Maier, Josef; Schulte, Ulrich

    2003-01-01

    The German Neurospora Genome Project has assembled sequences from ordered cosmid and BAC clones of linkage groups II and V of the genome of Neurospora crassa in 13 and 12 contigs, respectively. Including additional sequences located on other linkage groups a total of 12 Mb were subjected to a manual gene extraction and annotation process. The genome comprises a small number of repetitive elements, a low degree of segmental duplications and very few paralogous genes. The analysis of the 3218 identified open reading frames provides a first overview of the protein equipment of a filamentous fungus. Significantly, N.crassa possesses a large variety of metabolic enzymes including a substantial number of enzymes involved in the degradation of complex substrates as well as secondary metabolism. While several of these enzymes are specific for filamentous fungi many are shared exclusively with prokaryotes. PMID:12655011

  18. Improvement of tolerance to lead by filamentous fungus Pleurotus ostreatus HAU-2 and its oxidative responses.

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    Zhang, Shimin; Zhang, Xiaolin; Chang, Cheng; Yuan, Zhiyong; Wang, Ting; Zhao, Yong; Yang, Xitian; Zhang, Yuting; La, Guixiao; Wu, Kun; Zhang, Zhiming; Li, Xuanzhen

    2016-05-01

    Wastewater contaminated with heavy metals is a world-wide concern. One biological treatment strategy includes filamentous fungi capable of extracellular adsorption and intracellular bioaccumulation. Here we report that an acclimated strain of filamentous fungus Pleurotus ostreatus HAU-2 can withstand Pb up to 1500 mg L(-1) Pb, conditions in which the wildtype strain cannot grow. The acclimated strain grew in liquid culture under 500 mg L(-1) Pb without significant abnormity in biomass and morphology, and was able to remove significant amounts of heavy metals with rate of 99.1% at 200 mg L(-1) and 63.3% at 1500 mg L(-1). Intracellular bioaccumulation as well as extracellular adsorption both contributed the Pb reduction. Pb induced levels of H2O2, and its concentration reached 72.9-100.9 μmol g(-1) under 200-1000 mg L(-1) Pb. A relatively higher malonaldehyde (MDA) concentration (8.06-7.59 nmol g(-1)) was also observed at 500-1500 mg L(-1) Pb, indicating that Pb exposure resulted in oxidative damage. The fungal cells also defended against the attack of reactive oxygen species by producing antioxidants. Of the three antioxidant enzymes superoxide dismutase (SOD), peroxidase (POD) and catalase (CAT), CAT was the most responsive and the maximal enzyme activity was 15.8 U mg(-1) protein. Additionally, glutathione (GSH) might also play a role (3.16-3.21 mg g(-1) protein) in detoxification under relatively low Pb concentration (100-200 mg L(-1)). Our findings suggested that filamentous fungus could be selected for increased tolerance to heavy metals and that CAT and GSH might be important components of this tolerance.

  19. METABOLIC ENERGY GENERATION IN HYDROGENOSOMES OF THE ANAEROBIC FUNGUS NEOCALLIMASTIX - EVIDENCE FOR A FUNCTIONAL-RELATIONSHIP WITH MITOCHONDRIA

    NARCIS (Netherlands)

    MARVINSIKKEMA, FD; DRIESSEN, AJM; GOTTSCHAL, JC; PRINS, RA

    1994-01-01

    Anaerobic eukaryotes are often devoid of mitochondria but contain special organelles separated from the cytosol by a single (in fungi) or a double (in protozoa) membrane. Hydrogenosomes from the anaerobic fungus Neocallimastix sp. L2 are thought to catalyse the enzymic steps in the ATP-yielding meta

  20. The filamentous fungus Ashbya gossypii as a competitive industrial inosine producer.

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    Ledesma-Amaro, Rodrigo; Buey, Rubén M; Revuelta, José Luis

    2016-09-01

    Inosine is a nucleoside with growing biotechnological interest due to its recently attributed beneficial health effects and as a convenient precursor of the umami flavor. At present, most of the industrial inosine production relies on bacterial fermentations. In this work, we have metabolically engineered the filamentous fungus Ashbya gossypii to obtain strains able to excrete high amounts of inosine to the culture medium. We report that the disruption of only two key genes of the purine biosynthetic pathway efficiently redirect the metabolic flux, increasing 200-fold the excretion of inosine with respect to the wild type, up to 2.2 g/L. These results allow us to propose A. gossypii as a convenient candidate for large-scale nucleoside production, especially in view of the several advantages that Ashbya has with respect to the bacterial systems used at present for the industrial production of this food additive. Biotechnol. Bioeng. 2016;113: 2060-2063. © 2016 Wiley Periodicals, Inc.

  1. Epigenetic Control of Phenotypic Plasticity in the Filamentous Fungus Neurospora crassa.

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    Kronholm, Ilkka; Johannesson, Hanna; Ketola, Tarmo

    2016-12-07

    Phenotypic plasticity is the ability of a genotype to produce different phenotypes under different environmental or developmental conditions. Phenotypic plasticity is a ubiquitous feature of living organisms, and is typically based on variable patterns of gene expression. However, the mechanisms by which gene expression is influenced and regulated during plastic responses are poorly understood in most organisms. While modifications to DNA and histone proteins have been implicated as likely candidates for generating and regulating phenotypic plasticity, specific details of each modification and its mode of operation have remained largely unknown. In this study, we investigated how epigenetic mechanisms affect phenotypic plasticity in the filamentous fungus Neurospora crassa By measuring reaction norms of strains that are deficient in one of several key physiological processes, we show that epigenetic mechanisms play a role in homeostasis and phenotypic plasticity of the fungus across a range of controlled environments. In general, effects on plasticity are specific to an environment and mechanism, indicating that epigenetic regulation is context dependent and is not governed by general plasticity genes. Specifically, we found that, in Neurospora, histone methylation at H3K36 affected plastic response to high temperatures, H3K4 methylation affected plastic response to pH, but H3K27 methylation had no effect. Similarly, DNA methylation had only a small effect in response to sucrose. Histone deacetylation mainly decreased reaction norm elevation, as did genes involved in histone demethylation and acetylation. In contrast, the RNA interference pathway was involved in plastic responses to multiple environments.

  2. Quantification of the glucosamine content in the filamentous fungus Monascus ruber cultured on solid surfaces.

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    Chysirichote, Teerin; Reiji, Takahashi; Asami, Kazuhiro; Ohtaguchi, Kazuhisa

    2014-05-01

    We evaluated whether the glucosamine content in the filamentous fungus Monascus ruber NBRC 32318, cultured on a solid surface (agar) containing different carbon and nitrogen sources, could be used as a measure of biomass. The relationship between the amounts of glucosamine and biomass was independent of the cultivation period, but was dependent on the carbon source (D-glucose, D-fructose, maltose, sucrose, or rice starch) and the nitrogen source (ammonium chloride, sodium nitrate, monosodium glutamate, or yeast extract) in the agar; it was also dependent on the culture method (solid-surface culture or submerged culture). We concluded that the amount of glucosamine extracted from M. ruber is a useful index for the fungal biomass when the relationship between M. ruber biomass and glucosamine content has previously been calibrated for the carbon and nitrogen sources used. Examination of microphotographs of M. ruber hyphae in conjunction with quantification of the glucosamine and biomass contents indicated that the variation in the glucosamine content per unit biomass affects the hyphal morphology of the fungus, and especially the hyphal diameter.

  3. Identification of the augmin complex in the filamentous fungus Aspergillus nidulans.

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    Tomoya Edzuka

    Full Text Available Augmin is a protein complex that binds to spindle microtubules (MTs, recruits the potent MT nucleator, γ-tubulin, and thereby promotes the centrosome-independent MT generation within mitotic and meiotic spindles. Augmin is essential for acentrosomal spindle assembly, which is commonly observed during mitosis in plants and meiosis in female animals. In many animal somatic cells that possess centrosomes, the centrosome- and augmin-dependent mechanisms work cooperatively for efficient spindle assembly and cytokinesis. Yeasts have lost the augmin genes during evolution. It is hypothesized that their robust MT nucleation from the spindle pole body (SPB, the centrosome-equivalent structure in fungi, compensates for the lack of augmin. Intriguingly, however, a gene homologous to an augmin subunit (Aug6/AUGF has been found in the genome of filamentous fungi, which has the SPB as a robust MT nucleation centre. Here, we aimed to clarify if the augmin complex is present in filamentous fungi and to identify its role in mitosis. By analysing the Aug6-like gene in the filamentous fungus Aspergillus nidulans, we found that it forms a large complex with several other proteins that share weak but significant homology to known augmin subunits. In A. nidulans, augmin was enriched at the SPB and also associated with spindle MTs during mitosis. However, the augmin gene disruptants did not exhibit growth defects under normal, checkpoint-deficient, or MT-destabilised conditions. Moreover, we obtained no evidence that A. nidulans augmin plays a role in γ-tubulin recruitment or in mitotic cell division. Our study uncovered the conservation of the augmin complex in the fungal species, and further suggests that augmin has several functions, besides mitotic spindle MT nucleation, that are yet to be identified.

  4. Non-specific association between filamentous bacteria and fungus-growing ants.

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    Kost, Christian; Lakatos, Tanja; Böttcher, Ingo; Arendholz, Wolf-Rüdiger; Redenbach, Matthias; Wirth, Rainer

    2007-10-01

    Fungus-growing ants and their fungal cultivar form a highly evolved mutualism that is negatively affected by the specialized parasitic fungus Escovopsis. Filamentous Pseudonocardia bacteria occurring on the cuticle of attine ants have been proposed to form a mutualistic interaction with these ants in which they are vertically transmitted (i.e. from parent to offspring colonies). Given a strictly vertical transmission of Pseudonocardia, the evolutionary theory predicts a reduced genetic variability of symbionts among ant lineages. The aim of this study was to verify whether actinomycetes, which occur on Acromyrmex octospinosus leaf-cutting ants, meet this expectation by comparing their genotypic variability with restriction fragment length polymorphisms. Multiple actinomycete strains could be isolated from both individual ant workers and colonies (one to seven strains per colony). The colony specificity of actinomycete communities was high: Only 15% of all strains were isolated from more than one colony, and just 5% were present in both populations investigated. Partial sequencing of 16S ribosomal deoxyribonucleic acid of two of the isolated strains assigned both of them to the genus Streptomyces. Actinomycetes could also be isolated from workers of the two non-attine ant species Myrmica rugulosa and Lasius flavus. Sixty-two percent of the strains derived from attine ants and 80% of the strains isolated from non-attine ants inhibited the growth of Escovopsis. Our data suggest that the association between attine ants and their actinomycete symbionts is less specific then previously thought. Soil-dwelling actinomycetes may have been dynamically recruited from the environment (horizontal transmission), probably reflecting an adaptation to a diverse community of microbial pathogens.

  5. Epigenetic Control of Phenotypic Plasticity in the Filamentous Fungus Neurospora crassa

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    Ilkka Kronholm

    2016-12-01

    Full Text Available Phenotypic plasticity is the ability of a genotype to produce different phenotypes under different environmental or developmental conditions. Phenotypic plasticity is a ubiquitous feature of living organisms, and is typically based on variable patterns of gene expression. However, the mechanisms by which gene expression is influenced and regulated during plastic responses are poorly understood in most organisms. While modifications to DNA and histone proteins have been implicated as likely candidates for generating and regulating phenotypic plasticity, specific details of each modification and its mode of operation have remained largely unknown. In this study, we investigated how epigenetic mechanisms affect phenotypic plasticity in the filamentous fungus Neurospora crassa. By measuring reaction norms of strains that are deficient in one of several key physiological processes, we show that epigenetic mechanisms play a role in homeostasis and phenotypic plasticity of the fungus across a range of controlled environments. In general, effects on plasticity are specific to an environment and mechanism, indicating that epigenetic regulation is context dependent and is not governed by general plasticity genes. Specifically, we found that, in Neurospora, histone methylation at H3K36 affected plastic response to high temperatures, H3K4 methylation affected plastic response to pH, but H3K27 methylation had no effect. Similarly, DNA methylation had only a small effect in response to sucrose. Histone deacetylation mainly decreased reaction norm elevation, as did genes involved in histone demethylation and acetylation. In contrast, the RNA interference pathway was involved in plastic responses to multiple environments.

  6. Autophagy promotes survival in aging submerged cultures of the filamentous fungus Aspergillus niger.

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    Nitsche, Benjamin M; Burggraaf-van Welzen, Anne-Marie; Lamers, Gerda; Meyer, Vera; Ram, Arthur F J

    2013-09-01

    Autophagy is a well-conserved catabolic process constitutively active in eukaryotes that is involved in maintaining cellular homeostasis by the targeting of cytoplasmic content and organelles to vacuoles. Autophagy is strongly induced by the limitation of nutrients including carbon, nitrogen, and oxygen and is clearly associated with cell death. It has been demonstrated that the accumulation of empty hyphal compartments and cryptic growth in carbon-starved submerged cultures of the filamentous fungus Aspergillus niger is accompanied by a joint transcriptional induction of autophagy genes. This study examines the role of autophagy by deleting the atg1, atg8, and atg17 orthologs in A. niger and phenotypically analyzing the deletion mutants in surface and submerged cultures. The results indicate that atg1 and atg8 are essential for efficient autophagy, whereas deletion of atg17 has little to no effect on autophagy in A. niger. Depending on the kind of oxidative stress confronted with, autophagy deficiency renders A. niger either more resistant (menadione) or more sensitive (H2O2) to oxidative stress. Fluorescence microscopy showed that mitochondrial turnover upon carbon depletion in submerged cultures is severely blocked in autophagy-impaired A. niger mutants. Furthermore, automated image analysis demonstrated that autophagy promotes survival in maintained carbon-starved cultures of A. niger. Taken together, the results suggest that besides its function in nutrient recycling, autophagy plays important roles in physiological adaptation by organelle turnover and protection against cell death upon carbon depletion in submerged cultures.

  7. RNAi silencing of a cytochrome P450 monooxygenase disrupts the ability of a filamentous fungus, Graphium sp. to grow on short-chain gaseous alkanes and ethers

    Science.gov (United States)

    Graphium sp. (ATCC 58400), a filamentous fungus, is one of the few eukaryotes that grows on short-chain alkanes and ethers. In this study, we investigated the genetic underpinnings that enable this fungus to catalyze the first step in the alkane and ether oxidation pathway. A gene, CYP52L1, was iden...

  8. Macrophage receptors of polysaccharide isolated from a marine filamentous fungus Phoma herbarum YS4108

    Institute of Scientific and Technical Information of China (English)

    Song CHEN; Deng-ke YIN; Wen-bing YAO; Yi-dan WANG; Yi-ran ZHANG; Xiang-dong GAO

    2009-01-01

    Aim:YCP,a novel (1,4)-α-D-glucan,was isolated from the mycelium of the marine filamentous fungus Phoma herbarum YS4108.In this work,we investigated a YCP-binding cellular receptor expressed by macrophages and the intracellular signal transduction pathways involved in YCP-induced macrophage activation.Methods:Fluorescence-labeled YCP (fl-YCP) was prepared using the CDAP-activation method.Fluorescence confocal laser microscopy and fluorescence-activated cell sorting (FACS) were used to analyze the effect of fl-YCP on macrophages.To characterize the properties of the YCP receptor,carbohydrates and antibodies were used to inhibit the binding of fl-YCP to macrophages.Moreover,we investigated the role of membrane receptors Toll-like receptor 2 (TLR2),Toll-like receptor 4 (TLR4),Toll-like receptor 6 (TLR6) and complement receptor 3 (CR3).We also examined the role of the p38 kinase pathway in mediating nitric oxide (NO) production.Results:YCP had an in vitro stimulatory effect on the release of NO in macrophage,and fl-YCP can bind directly to receptors on the surface of macrophages in a time- and dose-dependent manner.Competition studies show that LPS,laminarin,anti-TLR4 antibody and anti-CD11b (CR3) antibody could inhibit fl-YCP binding to macrophages.Conversely,mannose,anti-TLR2 and anti-TLR6 antibody could not.Treatment of RAW264.7 cells with YCP resulted in significant activation of p38 in a time-dependent manner.The specific p38 inhibitor SB203580 abrogated YCP-induced NO generation.Treatment of RAW264.7 cells with anti-TLR4 antibody and anti-CR3 antibody significantly reduced YCP-induced NO production and p38 activation.Conclusion:We have demonstrated that YCP-induced NO production occurs through the TLR4 and CR3 membrane receptors in a p38 kinase-dependent manner in macrophages.

  9. The anaerobic fungus Neocallimastix sp. strain L2 : Growth and production of (Hemi)cellulolytic enzymes on a range of carbohydrate substrates

    NARCIS (Netherlands)

    Dijkerman, R; Ledeboer, J; op den Camp, H.J M; Prins, R.A; van der Drift, C

    1997-01-01

    The anaerobic fungus Neocallimastix sp. strain L2, isolated from the feces of a Ilama, was tested for growth on a range of soluble and insoluble carbohydrate substrates. The fungus was able to ferment glucose, cellobiose, fructose, lactose, maltose, sucrose, soluble starch, inulin, filter paper cell

  10. Report membrane transport of lactic acid in the filamentous fungus Rhizopus

    Science.gov (United States)

    The fungus Rhizopus is frequently used for fermentative production of lactic acid, but little is known about the mechanisms or proteins for transporting this carboxylic acid. Since transport of the lactate anion across the plasma membrane is critical to prevent acidification of the cytoplasm, we ev...

  11. Sulfation of a polysaccharide produced by a marine filamentous fungus Phoma herbarum YS4108 alters its antioxidant properties in vitro.

    Science.gov (United States)

    Yang, X B; Gao, X D; Han, F; Tan, R X

    2005-08-30

    Free radicals and other reactive oxygen species (ROS) are generated by all aerobic cells and are widely believed to play a significant role in aging as well as a number of degenerative or pathological diseases. This study compared the free radical-scavenging properties and antioxidant activity of YCP, a polysaccharide from the mycelium of a marine filamentous fungus Phoma herbarum YS 4108 and its two chemically sulfated derivatives YCP-S1 and YCP-S2. Sulfation, which masks hydroxyl groups of YCP polysaccharide molecule, could introduce new antioxidant activity, such as superoxide and hydroxyl radicals scavenging activity, metal chelating action, lipid peroxidation and linoleic acid oxidation inhibition capability. Furthermore, sulfated YCP was more potent than YCP at protecting erythrocytes against oxidative damage hemolysis. The current data suggest for the first time that sulfation of polysaccharide significantly increases its antioxidant activity and the chemical modification of polysaccharides may allow the preparation of derivatives with new properties and a variety of applications.

  12. Structure of Importin-α from a Filamentous Fungus in Complex with a Classical Nuclear Localization Signal.

    Directory of Open Access Journals (Sweden)

    Natalia E Bernardes

    Full Text Available Neurospora crassa is a filamentous fungus that has been extensively studied as a model organism for eukaryotic biology, providing fundamental insights into cellular processes such as cell signaling, growth and differentiation. To advance in the study of this multicellular organism, an understanding of the specific mechanisms for protein transport into the cell nucleus is essential. Importin-α (Imp-α is the receptor for cargo proteins that contain specific nuclear localization signals (NLSs that play a key role in the classical nuclear import pathway. Structures of Imp-α from different organisms (yeast, rice, mouse, and human have been determined, revealing that this receptor possesses a conserved structural scaffold. However, recent studies have demonstrated that the Impα mechanism of action may vary significantly for different organisms or for different isoforms from the same organism. Therefore, structural, functional, and biophysical characterization of different Impα proteins is necessary to understand the selectivity of nuclear transport. Here, we determined the first crystal structure of an Impα from a filamentous fungus which is also the highest resolution Impα structure already solved to date (1.75 Å. In addition, we performed calorimetric analysis to determine the affinity and thermodynamic parameters of the interaction between Imp-α and the classical SV40 NLS peptide. The comparison of these data with previous studies on Impα proteins led us to demonstrate that N. crassa Imp-α possess specific features that are distinct from mammalian Imp-α but exhibit important similarities to rice Imp-α, particularly at the minor NLS binding site.

  13. Degradation of 3-phenoxybenzoic acid by a filamentous fungus Aspergillus oryzae M-4 strain with self-protection transformation.

    Science.gov (United States)

    Zhu, Yuanting; Li, Jianlong; Yao, Kai; Zhao, Nan; Zhou, Kang; Hu, Xinjie; Zou, Likou; Han, Xinfeng; Liu, Aiping; Liu, Shuliang

    2016-11-01

    A novel filamentous fungus M-4 strain was isolated from soy sauce koji and identified as Aspergillus oryzae (Collection number: CGMCC 11645) on the basis of morphological characteristics and internal transcribed spacer sequence. M-4 could degrade 80.62 % of 3-phenoxybenzoic acid (3-PBA; 100 mg L(-1)) within 5 days. 3-PBA degradation occurred in accordance with first-order kinetics. The degradation metabolites of 3-PBA were identified through high-performance liquid chromatography-mass spectrometry (HPLC-MS). Relevant enzymatic activities and substrate utilization were also investigated, which indicated that M-4 could effectively degrade the intermediates of 3-PBA. Base on analysis of these metabolites, a novel biochemical pathway for the degradation of 3-PBA was proposed. There exists a mutual transformation between 3-phenoxy-benzyl alcohol and 3-PBA, which was firstly reported about the degradation of 3-PBA and may be attributed to self-protection transformation of M-4; subsequently, 3-PBA was gradually transformed into phenol, 3-hydroxy-5-phenoxy benzoic acid, protocatechuic acid and gallic acid. The safety of M-4 was evaluated via an acute toxicity test in vivo. The biodegradation ability of M-4 without toxic effects reveals that this fungus may be likely to be used for eliminating 3-PBA from contaminated environment or fermented foods.

  14. Effects of emulsified octadecanic acids on gas production and cellulolysis by the rumen anaerobic fungus, Piromyces communis M014.

    Science.gov (United States)

    Kim, Chang-H; Lee, Shin J; Ha, Jong K; Kim, Wan Y; Lee, Sung S

    2008-02-01

    Responses of the rumen anaerobic fungus, Piromyces communis M014, to octadecanic long-chain fatty acids (LCFAs) were evaluated by measuring total and hydrogen gas productions, filter paper (FP) cellulose degradation and polysaccharidase enzyme activities. Octadecanic acids (stearic acid, C(18:0); oleic acid, C(18:1); linoleic acid, C(18:2) and linolenic acid, C(18:3)) were emulsified by ultrasonication under anaerobic conditions, and added to the medium at the level of 0.001%. When P. communis M014 was grown in culture with stearic and oleic acids, the cumulative gas production, FP cellulose digestion and enzyme activities were significantly (pinhibited all of the investigated parameters, including cellulose degradation, enzyme activities and gas production, up to 168h incubation. These results indicated that stearic and oleic acids tended to have stimulatory effects on fungal cellulolysis, whereas linolenic acid caused a significant (pinhibition of gas production and cellulase enzyme activity was.

  15. Biosorption of cadmium by a metal-resistant filamentous fungus isolated from chicken manure compost.

    Science.gov (United States)

    Xu, Xingjian; Xia, Lu; Huang, Qiaoyun; Gu, Ji-Dong; Chen, Wenli

    2012-01-01

    A fungus, XJ-1, isolated from chicken manure compost was phylogenetically related to Penicillium chrysogenum. The minimum inhibitory concentrations of the fungus for Cd2+, Cu2+, Cr3+, Cr6+, Co2+ and Zn2+ were 300, 85, 55, 8, 25 and 70mM on plates and 200, 65, 30, 2, 30 and 48mM in liquid media, respectively. Biosorption of Cd2+ by XJ-1 was investigated as a function of initial pH, contact time, biomass loading and Cd+ concentration. According to the Langmuir isotherm, the maximum adsorption of Cd2+ was 100.41 mg g(-1) dry biomass. Analyses using FTIR, SEM and XPS showed that the functional groups -OH and -C=O on the XJ-1 cell wall are the dominant binding sites for Cd2+. The results indicate that XJ-1 biomass is an efficient biosorbent for Cd2+ and has great potential for the in situ remediation of environments contaminated with heavy metals.

  16. Genomic adaptations of the halophilic Dead Sea filamentous fungus Eurotium rubrum.

    Science.gov (United States)

    Kis-Papo, Tamar; Weig, Alfons R; Riley, Robert; Peršoh, Derek; Salamov, Asaf; Sun, Hui; Lipzen, Anna; Wasser, Solomon P; Rambold, Gerhard; Grigoriev, Igor V; Nevo, Eviatar

    2014-05-09

    The Dead Sea is one of the most hypersaline habitats on Earth. The fungus Eurotium rubrum (Eurotiomycetes) is among the few species able to survive there. Here we highlight its adaptive strategies, based on genome analysis and transcriptome profiling. The 26.2 Mb genome of E. rubrum shows, for example, gains in gene families related to stress response and losses with regard to transport processes. Transcriptome analyses under different salt growth conditions revealed, among other things differentially expressed genes encoding ion and metabolite transporters. Our findings suggest that long-term adaptation to salinity requires cellular and metabolic responses that differ from short-term osmotic stress signalling. The transcriptional response indicates that halophilic E. rubrum actively counteracts the salinity stress. Many of its genes encode for proteins with a significantly higher proportion of acidic amino acid residues. This trait is characteristic of the halophilic prokaryotes as well, supporting the theory of convergent evolution under extreme hypersaline stress.

  17. Dynamics of actin cables in polarized growth of the filamentous fungus Aspergillus nidulans

    Directory of Open Access Journals (Sweden)

    Anna eBergs

    2016-05-01

    Full Text Available Highly polarized growth of filamentous fungi requires a continuous supply of proteins and lipids to the hyphal tip. This transport is managed by vesicle trafficking via the actin and microtubule cytoskeletons and their associated motor proteins. Particularly, actin cables originating from the hyphal tip are essential for hyphal growth. Although specific marker proteins to visualize actin cables have been developed in filamentous fungi, the exact organization and dynamics of actin cables has remained elusive. Here we visualized actin cables using tropomyosin (TpmA and Lifeact fused to fluorescent proteins in Aspergillus nidulans and studied the dynamics and regulation. GFP tagged TpmA visualized dynamic actin cables formed from the hyphal tip with cycles of elongation and shrinkage. The elongation and shrinkage rates of actin cables were similar and approximately 0.6 μm/s. Comparison of actin markers revealed that high concentrations of Lifeact reduced actin dynamics. Simultaneous visualization of actin cables and microtubules suggests temporally and spatially coordinated polymerization and depolymerization between the two cytoskeletons. Our results provide new insights into the molecular mechanism of ordered polarized growth regulated by actin cables and microtubules.

  18. Septin phosphorylation and coiled-coil domains function in cell and septin ring morphology in the filamentous fungus Ashbya gossypii.

    Science.gov (United States)

    Meseroll, Rebecca A; Occhipinti, Patricia; Gladfelter, Amy S

    2013-02-01

    Septins are a class of GTP-binding proteins conserved throughout many eukaryotes. Individual septin subunits associate with one another and assemble into heteromeric complexes that form filaments and higher-order structures in vivo. The mechanisms underlying the assembly and maintenance of higher-order structures in cells remain poorly understood. Septins in several organisms have been shown to be phosphorylated, although precisely how septin phosphorylation may be contributing to the formation of high-order septin structures is unknown. Four of the five septins expressed in the filamentous fungus, Ashbya gossypii, are phosphorylated, and we demonstrate here the diverse roles of these phosphorylation sites in septin ring formation and septin dynamics, as well as cell morphology and viability. Intriguingly, the alteration of specific sites in Cdc3p and Cdc11p leads to a complete loss of higher-order septin structures, implicating septin phosphorylation as a regulator of septin structure formation. Introducing phosphomimetic point mutations to specific sites in Cdc12p and Shs1p causes cell lethality, highlighting the importance of normal septin modification in overall cell function and health. In addition to discovering roles for phosphorylation, we also present diverse functions for conserved septin domains in the formation of septin higher-order structure. We previously showed the requirement for the Shs1p coiled-coil domain in limiting septin ring size and reveal here that, in contrast to Shs1p, the coiled-coil domains of Cdc11p and Cdc12p are required for septin ring formation. Our results as a whole reveal novel roles for septin phosphorylation and coiled-coil domains in regulating septin structure and function.

  19. Genotoxicity of the cyclo-oxygenase-inhibitor sulindac sulfide in the filamentous fungus Aspergillus nidulans Genotoxicidade de sulfeto de sulindaco em Aspergillus nidulans

    OpenAIRE

    Claudinéia Conationi da Silva Franco; Claudia Tiemi Miyamoto; Juliane Rocha de Sant'Anna; Marialba Avezum Alves Castro-Prado

    2007-01-01

    Sulindac sulfide is a non-steroidal anti-inflammatory drug (NSAID) with chemopreventive effect on human cancer cells. Due to the involvement of the somatic recombination in the carcinogenic process, sulindac sulfide's recombinogenic potential was evaluated by the Homozygotization Index (HI) in the filamentous fungus Aspergillus nidulans. The drug's recombinogenic potential was evaluated by its capacity to induce homozygosis of recessive genes from heterozygous diploid cells. Sulindac sulfide ...

  20. Morphological changes of the filamentous fungus Mucor mucedo and inhibition of chitin synthase activity induced by anethole.

    Science.gov (United States)

    Yutani, Masahiro; Hashimoto, Yukie; Ogita, Akira; Kubo, Isao; Tanaka, Toshio; Fujita, Ken-ichi

    2011-11-01

    trans-Anethole (anethole), a major component of anise oil, has a broad antimicrobial spectrum with antimicrobial activity relatively weaker than those of well-known antibiotics, and significantly enhances the antifungal activity of polygodial and dodecanol against the baker's yeast Saccharomyces cerevisiae and human pathogenic yeast Candida albicans. However, the antifungal mechanism of anethole is unresolved. Anethole demonstrated antifungal activity against the filamentous fungus, Mucor mucedo IFO 7684, accompanied by hyphal morphological changes such as swollen hyphae at the tips. Its minimum growth inhibitory concentration was 0.625 mM. A hyperosmotic condition (1.2 M sorbitol) restricted the induction of morphological changes, while hypoosmotic treatment (distilled water) induced bursting of hyphal tips and leakage of cytoplasmic constituents. Furthermore, anethole dose-dependently inhibited chitin synthase (CHS) activity in permeabilized hyphae in an uncompetitive manner. These results suggest that the morphological changes of M. mucedo could be explained by the fragility of cell walls caused by CHS inhibition.

  1. Supramolecular organization of cytochrome c oxidase- and alternative oxidase-dependent respiratory chains in the filamentous fungus Podospora anserina.

    Science.gov (United States)

    Krause, Frank; Scheckhuber, Christian Q; Werner, Alexandra; Rexroth, Sascha; Reifschneider, Nicole H; Dencher, Norbert A; Osiewacz, Heinz D

    2004-06-18

    To elucidate the molecular basis of the link between respiration and longevity, we have studied the organization of the respiratory chain of a wild-type strain and of two long-lived mutants of the filamentous fungus Podospora anserina. This established aging model is able to respire by either the standard or the alternative pathway. In the latter pathway, electrons are directly transferred from ubiquinol to the alternative oxidase and thus bypass complexes III and IV. We show that the cytochrome c oxidase pathway is organized according to the mammalian "respirasome" model (Schägger, H., and Pfeiffer, K. (2000) EMBO J. 19, 1777-1783). In contrast, the alternative pathway is composed of distinct supercomplexes of complexes I and III (i.e. I(2) and I(2)III(2)), which have not been described so far. Enzymatic analysis reveals distinct functional properties of complexes I and III belonging to either cytochrome c oxidase- or alternative oxidase-dependent pathways. By a gentle colorless-native PAGE, almost all of the ATP synthases from mitochondria respiring by either pathway were preserved in the dimeric state. Our data are of significance for the understanding of both respiratory pathways as well as lifespan control and aging.

  2. The evolutionary imprint of domestication on genome variation and function of the filamentous fungus Aspergillus oryzae.

    Science.gov (United States)

    Gibbons, John G; Salichos, Leonidas; Slot, Jason C; Rinker, David C; McGary, Kriston L; King, Jonas G; Klich, Maren A; Tabb, David L; McDonald, W Hayes; Rokas, Antonis

    2012-08-01

    The domestication of animals, plants, and microbes fundamentally transformed the lifestyle and demography of the human species [1]. Although the genetic and functional underpinnings of animal and plant domestication are well understood, little is known about microbe domestication [2-6]. Here, we systematically examined genome-wide sequence and functional variation between the domesticated fungus Aspergillus oryzae, whose saccharification abilities humans have harnessed for thousands of years to produce sake, soy sauce, and miso from starch-rich grains, and its wild relative A. flavus, a potentially toxigenic plant and animal pathogen [7]. We discovered dramatic changes in the sequence variation and abundance profiles of genes and wholesale primary and secondary metabolic pathways between domesticated and wild relative isolates during growth on rice. Our data suggest that, through selection by humans, an atoxigenic lineage of A. flavus gradually evolved into a "cell factory" for enzymes and metabolites involved in the saccharification process. These results suggest that whereas animal and plant domestication was largely driven by Neolithic "genetic tinkering" of developmental pathways, microbe domestication was driven by extensive remodeling of metabolism.

  3. Wood utilization is dependent on catalase activities in the filamentous fungus Podospora anserina.

    Science.gov (United States)

    Bourdais, Anne; Bidard, Frederique; Zickler, Denise; Berteaux-Lecellier, Veronique; Silar, Philippe; Espagne, Eric

    2012-01-01

    Catalases are enzymes that play critical roles in protecting cells against the toxic effects of hydrogen peroxide. They are implicated in various physiological and pathological conditions but some of their functions remain unclear. In order to decipher the role(s) of catalases during the life cycle of Podospora anserina, we analyzed the role of the four monofunctional catalases and one bifunctional catalase-peroxidase genes present in its genome. The five genes were deleted and the phenotypes of each single and all multiple mutants were investigated. Intriguingly, although the genes are differently expressed during the life cycle, catalase activity is dispensable during both vegetative growth and sexual reproduction in laboratory conditions. Catalases are also not essential for cellulose or fatty acid assimilation. In contrast, they are strictly required for efficient utilization of more complex biomass like wood shavings by allowing growth in the presence of lignin. The secreted CATB and cytosolic CAT2 are the major catalases implicated in peroxide resistance, while CAT2 is the major player during complex biomass assimilation. Our results suggest that P. anserina produces external H(2)O(2) to assimilate complex biomass and that catalases are necessary to protect the cells during this process. In addition, the phenotypes of strains lacking only one catalase gene suggest that a decrease of catalase activity improves the capacity of the fungus to degrade complex biomass.

  4. Wood utilization is dependent on catalase activities in the filamentous fungus Podospora anserina.

    Directory of Open Access Journals (Sweden)

    Anne Bourdais

    Full Text Available Catalases are enzymes that play critical roles in protecting cells against the toxic effects of hydrogen peroxide. They are implicated in various physiological and pathological conditions but some of their functions remain unclear. In order to decipher the role(s of catalases during the life cycle of Podospora anserina, we analyzed the role of the four monofunctional catalases and one bifunctional catalase-peroxidase genes present in its genome. The five genes were deleted and the phenotypes of each single and all multiple mutants were investigated. Intriguingly, although the genes are differently expressed during the life cycle, catalase activity is dispensable during both vegetative growth and sexual reproduction in laboratory conditions. Catalases are also not essential for cellulose or fatty acid assimilation. In contrast, they are strictly required for efficient utilization of more complex biomass like wood shavings by allowing growth in the presence of lignin. The secreted CATB and cytosolic CAT2 are the major catalases implicated in peroxide resistance, while CAT2 is the major player during complex biomass assimilation. Our results suggest that P. anserina produces external H(2O(2 to assimilate complex biomass and that catalases are necessary to protect the cells during this process. In addition, the phenotypes of strains lacking only one catalase gene suggest that a decrease of catalase activity improves the capacity of the fungus to degrade complex biomass.

  5. INFLUENCE OF METRONIDAZOLE, CO, CO2, AND METHANOGENS ON THE FERMENTATIVE METABOLISM OF THE ANAEROBIC FUNGUS NEOCALLIMASTIX SP STRAIN L2

    NARCIS (Netherlands)

    MARVINSIKKEMA, FD; REES, E; KRAAK, MN; GOTTSCHAL, JC; PRINS, RA

    1993-01-01

    The effects of metronidazole, CO, methanogens, and CO, on the fermentation of glucose by the anaerobic fungus Neocallimastix sp. strain L2 were investigated. Both metronidazole and CO caused a shift in the fermentation products from predominantly H-2, acetate, and formate to lactate as the major pro

  6. A mitochondrial-like targeting signal on the hydrogenosomal malic enzyme from the anaerobic fungus Neocallimastix frontalis : Support for the hypothesis that hydrogenosomes are modified mitochondria

    NARCIS (Netherlands)

    vanderGiezen, M; Rechinger, KB; Svendsen, [No Value; Durand, R; Hirt, RP; Fevre, M; Embley, TM; Prins, RA

    1997-01-01

    The hydrogenosomal malic enzyme (ME) was purified from the anaerobic fungus Neocallimastix frontalis. Using reverse genetics, the corresponding cDNA was isolated and characterized. The deduced amino acid sequence of the ME showed high similarity to ME from metazoa, plants and protists. Putative func

  7. Molecular and functional characterization of a Rho GDP dissociation inhibitor in the filamentous fungus Tuber borchii

    Directory of Open Access Journals (Sweden)

    Stocchi Vilberto

    2008-04-01

    Full Text Available Abstract Background Small GTPases of the Rho family function as tightly regulated molecular switches that govern important cellular functions in eukaryotes. Several families of regulatory proteins control their activation cycle and subcellular localization. Members of the guanine nucleotide dissociation inhibitor (GDI family sequester Rho GTPases from the plasma membrane and keep them in an inactive form. Results We report on the characterization the RhoGDI homolog of Tuber borchii Vittad., an ascomycetous ectomycorrhizal fungus. The Tbgdi gene is present in two copies in the T. borchii genome. The predicted amino acid sequence shows high similarity to other known RhoGDIs. Real time PCR analyses revealed an increased expression of Tbgdi during the phase preparative to the symbiosis instauration, in particular after stimulation with root exudates extracts, that correlates with expression of Tbcdc42. In a translocation assay TbRhoGDI was able to solubilize TbCdc42 from membranes. Surprisingly, TbRhoGDI appeared not to interact with S. cerevisiae Cdc42, precluding the use of yeast as a surrogate model for functional studies. To study the role of TbRhoGDI we performed complementation experiments using a RhoGDI null strain of Dictyostelium discoideum, a model organism where the roles of Rho signaling pathways are well established. For comparison, complementation with mammalian RhoGDI1 and LyGDI was also studied in the null strain. Although interacting with Rac1 isoforms, TbRhoGDI was not able to revert the defects of the D. discoideum RhoGDI null strain, but displayed an additional negative effect on the cAMP-stimulated actin polymerization response. Conclusion T. borchii expresses a functional RhoGDI homolog that appears as an important modulator of cytoskeleton reorganization during polarized apical growth that antecedes symbiosis instauration. The specificity of TbRhoGDI actions was underscored by its inability to elicit a growth defect in S

  8. The polo-like kinase PLKA is required for initiation and progression through mitosis in the filamentous fungus Aspergillus nidulans.

    Science.gov (United States)

    Bachewich, Catherine; Masker, Kathryn; Osmani, Stephen

    2005-01-01

    Polo-like kinases (PLK) function during multiple stages of mitotic progression and in cytokinesis. We identified and cloned a PLK homologue in Aspergillus nidulans, plkA, which is the first PLK reported in a filamentous fungus and the largest member of the PLK family to date. As plkA was essential, the effects of overexpression and localization of protein in living cells were explored to determine PLKA function. Overexpression of PLKA permitted hyphal formation, but blocked nuclear division in interphase. In NIMA or NIMT temperature-sensitive backgrounds, overexpression of PLKA impaired normal entry into mitosis upon release from restrictive temperature, supporting a role for PLKA during G2/M. In the few mitotic cells present, spindles were monopolar or disorganized, and chromatin condensation and segregation were impaired, suggesting additional roles for PLKA in spindle formation and in chromosome dynamics. Consistent with this, green fluorescent protein (GFP)-tagged PLKA could localize to the spb during interphase, and to the spb and nucleus throughout mitosis. Intriguingly, PLKA remained on the spb during telophase and into G1, in contrast to other PLK. In addition, spb localization was independent of NIMA function, unlike that demonstrated in Schizosaccharomyces pombe where PLK localization to the spb required the NIMA homologue Fin1. PLKA was not detected at cortical, septation-associated sites, and overexpression did not drive septum formation, also in contrast to that observed with other PLK. Therefore, PLKA is important for multiple events during mitosis, similar to PLK in higher organisms, but exhibits differences in size, localization and influence on septation/cytokinesis, suggesting additional novel regulatory features.

  9. Harvesting of Chlorella sorokiniana by co-culture with the filamentous fungus Isaria fumosorosea: A potential sustainable feedstock for hydrothermal gasification.

    Science.gov (United States)

    Mackay, Stephen; Gomes, Eduardo; Holliger, Christof; Bauer, Rolene; Schwitzguébel, Jean-Paul

    2015-06-01

    Despite recent advances in down-stream processing, production of microalgae remains substantially limited because of economical reasons. Harvesting and dewatering are the most energy-intensive processing steps in their production and contribute 20-30% of total operational cost. Bio-flocculation of microalgae by co-cultivation with filamentous fungi relies on the development of large structures that facilitate cost effective harvesting. A yet unknown filamentous fungus was isolated as a contaminant from a microalgal culture and identified as Isaria fumosorosea. Blastospores production was optimized in minimal medium and the development of pellets, possibly lichens, was followed when co-cultured with Chlorella sorokiniana under strict autotrophic conditions. Stable pellets (1-2mm) formed rapidly at pH 7-8, clearing the medium of free algal cells. Biomass was harvested with large inexpensive filters, generating wet slurry suitable for hydrothermal gasification. Nutrient rich brine from the aqueous phase of hydrothermal gasification supported growth of the fungus and may increase the process sustainability.

  10. RNAi silencing of a cytochrome P450 monoxygenase disrupts the ability of a filamentous fungus, Graphium sp., to grow on short-chain gaseous alkanes and ethers.

    Science.gov (United States)

    Trippe, Kristin M; Wolpert, Thomas J; Hyman, Michael R; Ciuffetti, Lynda M

    2014-02-01

    Graphium sp. (ATCC 58400), a filamentous fungus, is one of the few eukaryotes that grows on short-chain alkanes and ethers. In this study, we investigated the genetic underpinnings that enable this fungus to catalyze the first step in the alkane and ether oxidation pathway. A gene, CYP52L1, was identified, cloned and functionally characterized as an alkane-oxidizing cytochrome P450 (GSPALK1). Analysis of CYP52L1 suggests that it is a member of the CYP52 cytochrome P450 family, which is comprised of medium- and long-chain alkane-oxidizing enzymes found in yeasts. However, phylogenetic analysis of GSPALK1 with other CYP52 members suggests they are not closely related. Post-transcriptional ds-RNA-mediated gene silencing of CYP52L1 severely reduced the ability of this fungus to oxidize alkanes and ethers, however, downstream metabolic steps in these pathways were unaffected. Collectively, the results of this study suggest that GSPALK1 is the enzyme that catalyzes the initial oxidation of alkanes and ethers but is not involved in the later steps of alkane or ether metabolism.

  11. Influence of different pre-treatment routes on the anaerobic digestion of a filamentous algae

    DEFF Research Database (Denmark)

    Ehimen, Ehiazesebhor Augustine; Holm-Nielsen, Jens Bo; Poulsen, M.

    2013-01-01

    The anaerobic digestion of outdoor cultivated Rhizoclonium biomass was investigated in this study. The influence of applying mechanical and biological pre-treatment methods prior to the biomass digestion on the overall methane yields was examined. The results show that the application of a combined...... biomass blending (treatment improved the methane yields by >20% compared to use of a mechanical size reduction method alone. The methane yields from Rhizoclonium biomass were however observed to be considerably lower than those of other algae species from...

  12. Defined enzyme cocktail from the anaerobic fungus Orpinomyces sp. strain C1A effectively releases sugars from pretreated corn stover and switchgrass

    Science.gov (United States)

    Morrison, Jessica M.; Elshahed, Mostafa S.; Youssef, Noha H.

    2016-01-01

    The anaerobic fungus Orpinomyces strain C1A is capable of growth on various types of lignocellulosic substrates, and harbors an impressive reservoir of carbohydrate active enzymes (CAZymes). Using a minimum enzyme cocktail strategy, we constituted a four-component lignocellulolytic cocktail derived from highly transcribed C1A, and evaluated its efficacy against pretreated corn stover and switchgrass. Hydrolysis yields ranged between 65–77.4%, depending on the lignocellulosic substrate and pretreatment applied. Addition of a highly expressed anaerobic fungal swollenin improved hydrolysis yields by up to 7%. Compared to the commercial cocktail CTec2, these anaerobic fungal cocktails provided comparable or slightly lower hydrolysis yields. Further, the differences in efficacy between commercial and anaerobic cocktails were often only realized after extended (168 hr) incubations. Under certain conditions, the hydrolysis yields of the anaerobic fungal cocktail was slightly superior to that realized by CTec2. We attribute the observed high hydrolysis yields to the high specific activity and affinity of the individual enzymes of the cocktail, as well as the high level of synergy and multi-functionality observed in multiple components. Collectively, this effort provides a novel platform for constructing highly effective enzymes for biofuel production and represents the first lignocellulolytic enzyme cocktail created from anaerobic fungal enzymes. PMID:27381262

  13. Endo-β-N-acetylglucosamidases (ENGases) in the fungus Trichoderma atroviride: possible involvement of the filamentous fungi-specific cytosolic ENGase in the ERAD process.

    Science.gov (United States)

    Tzelepis, Georgios; Hosomi, Akira; Hossain, Tanim Jabid; Hirayama, Hiroto; Dubey, Mukesh; Jensen, Dan Funck; Suzuki, Tadashi; Karlsson, Magnus

    2014-06-27

    N-Glycosylation is an important post-translational modification of proteins, which mainly occurs in the endoplasmic reticulum (ER). Glycoproteins that are unable to fold properly are exported to the cytosol for degradation by a cellular system called ER-associated degradation (ERAD). Once misfolded glycoproteins are exported to the cytosol, they are subjected to deglycosylation by peptide:N-glycanase (PNGase) to facilitate the efficient degradation of misfolded proteins by the proteasome. Interestingly, the ortholog of PNGase in some filamentous fungi was found to be an inactive deglycosylating enzyme. On the other hand, it has been shown that in filamentous fungi genomes, usually two different fungi-specific endo-β-N-acetylglucosamidases (ENGases) can be found; one is predicted to be localized in the cytosol and the other to have a signal sequence, while the functional importance of these enzymes remains to be clarified. In this study the ENGases of the filamentous fungus Trichoderma atroviride was characterized. By heterologous expression of the ENGases Eng18A and Eng18B in Saccharomyces cerevisiae, it was found that both ENGases are active deglycosylating enzymes. Interestingly, only Eng18B was able to enhance the efficient degradation of the RTL protein, a PNGase-dependent ERAD substrate, implying the involvement of this enzyme in the ERAD process. These results indicate that T. atroviride Eng18B may deglycosylate misfolded glycoproteins, substituting the function of the cytoplasmic PNGase in the ERAD process.

  14. A mutation in the gene encoding cytochrome c1 leads to a decreased ROS content and to a long-lived phenotype in the filamentous fungus Podospora anserina.

    Science.gov (United States)

    Sellem, Carole H; Marsy, Sophie; Boivin, Antoine; Lemaire, Claire; Sainsard-Chanet, Annie

    2007-07-01

    We present here the properties of a complex III loss-of-function mutant of the filamentous fungus Podospora anserina. The mutation corresponds to a single substitution in the second intron of the gene cyc1 encoding cytochrome c(1), leading to a splicing defect. The cyc1-1 mutant is long-lived, exhibits a defect in ascospore pigmentation, has a reduced growth rate and a reduced ROS production associated with a stabilisation of its mitochondrial DNA. We also show that increased longevity is linked with morphologically modified mitochondria and an increased number of mitochondrial genomes. Overexpression of the alternative oxidase rescues all these phenotypes and restores aging. Interestingly, the absence of complex III in this mutant is not paralleled with a deficiency in complex I activity as reported in mammals although the respiratory chain of P. anserina has recently been demonstrated to be organized according to the "respirasome" model.

  15. The gene for a lectin-like protein is transcriptionally activated during sexual development, but is not essential for fruiting body formation in the filamentous fungus Sordaria macrospora

    Directory of Open Access Journals (Sweden)

    Cebula Patricia

    2005-11-01

    Full Text Available Abstract Background The filamentous fungus Sordaria macrospora forms complex three-dimensional fruiting bodies called perithecia that protect the developing ascospores and ensure their proper discharge. In previous microarray analyses, several genes have been identified that are downregulated in sterile mutants compared to the wild type. Among these genes was tap1 (transcript associated with perithecial development, a gene encoding a putative lectin homolog. Results Analysis of tap1 transcript levels in the wild type under conditions allowing only vegetative growth compared to conditions that lead to fruiting body development showed that tap1 is not only downregulated in developmental mutants but is also upregulated in the wild type during fruiting body development. We have cloned and sequenced a 3.2 kb fragment of genomic DNA containing the tap1 open reading frame and adjoining sequences. The genomic region comprising tap1 is syntenic to its homologous region in the closely related filamentous fungus Neurospora crassa. To determine whether tap1 is involved in fruiting body development in S. macrospora, a knockout construct was generated in which the tap1 open reading frame was replaced by the hygromycin B resistance gene hph under the control of fungal regulatory regions. Transformation of the S. macrospora wild type with this construct resulted in a tap1 deletion strain where tap1 had been replaced by the hph cassette. The knockout strain displayed no phenotypic differences under conditions of vegetative growth and sexual development when compared to the wild type. Double mutants carrying the Δtap1 allele in several developmental mutant backgrounds were phenotypically similar to the corresponding developmental mutant strains. Conclusion The tap1 transcript is strongly upregulated during sexual development in S. macrospora; however, analysis of a tap1 knockout strain shows that tap1 is not essential for fruiting body formation in S. macrospora.

  16. Physiological traits of Penicillium glabrum strain LCP 08.5568, a filamentous fungus isolated from bottled aromatized mineral water.

    Science.gov (United States)

    Nevarez, L; Vasseur, V; Le Madec, A; Le Bras, M A; Coroller, L; Leguérinel, I; Barbier, G

    2009-04-15

    Penicillium glabrum is a ubiquitous fungus distributed world wide. This fungus is a frequent contaminant in the food manufacturing industry. Environmental factors such as temperature, water activity and pH have a great influence on fungal development. In this study, a strain of P. glabrum referenced to as LCP 08.5568, has been isolated from a bottle of aromatized mineral water. The effects of temperature, a(w) and pH on radial growth rate were assessed on Czapeck Yeast Agar (CYA) medium. Models derived from the cardinal model with inflection [Rosso et al., 1993 An unexpected correlation between cardinal temperatures of microbial growth highlighted by a new model. J. Theor. Bio. 162, 447-463.] were used to fit the experimental data and determine for each factor, the cardinal parameters (minimum, optimum and maximum). Precise characterisation of the growth conditions for such a fungal contaminant, has an evident interest to understand and to prevent spoilage of food products.

  17. Bioaugmentation with an anaerobic fungus in a two-stage process for biohydrogen and biogas production using corn silage and cattail.

    Science.gov (United States)

    Nkemka, Valentine Nkongndem; Gilroyed, Brandon; Yanke, Jay; Gruninger, Robert; Vedres, Darrell; McAllister, Tim; Hao, Xiying

    2015-06-01

    Bioaugmentation with an anaerobic fungus, Piromyces rhizinflata YM600, was evaluated in an anaerobic two-stage system digesting corn silage and cattail. Comparable methane yields of 328.8±16.8mLg(-1)VS and 295.4±14.5mLg(-1)VS and hydrogen yields of 59.4±4.1mLg(-1)VS and 55.6±6.7mLg(-1)VS were obtained for unaugmented and bioaugmented corn silage, respectively. Similar CH4 yields of 101.0±4.8mLg(-1)VS and 104±19.1mLg(-1)VS and a low H2 yield (biohydrogen production.

  18. Septin Phosphorylation and Coiled-Coil Domains Function in Cell and Septin Ring Morphology in the Filamentous Fungus Ashbya gossypii

    OpenAIRE

    Meseroll, Rebecca A.; Occhipinti, Patricia; Gladfelter, Amy S.

    2013-01-01

    Septins are a class of GTP-binding proteins conserved throughout many eukaryotes. Individual septin subunits associate with one another and assemble into heteromeric complexes that form filaments and higher-order structures in vivo. The mechanisms underlying the assembly and maintenance of higher-order structures in cells remain poorly understood. Septins in several organisms have been shown to be phosphorylated, although precisely how septin phosphorylation may be contributing to the formati...

  19. Massive Changes in Genome Architecture Accompany the Transition to Self-Fertility in the filamentous Fungus Neurospora tetrasperma

    Energy Technology Data Exchange (ETDEWEB)

    Ellison, Christoper; Stajich, Jason; Jacobson, David; Nativ, Donald; Lapidus, Alla; Foster, Brian; Aerts, Andrea; Riley, Robert; Lindquist, Erika; Grigoriev, Igor; Taylor, John

    2011-05-16

    A large region of suppressed recombination surrounds the sex-determining locus of the self-fertile fungus Neurospora tetrasperma. This region encompasses nearly one-fifth of the N. tetrasperma genome and suppression of recombination is necessary for self-fertility. The similarity of the N. tetrasperma mating chromosome to plant and animal sex chromosomes and its recent origin (5 MYA), combined with a long history of genetic and cytological research, make this fungus an ideal model for studying the evolutionary consequences of suppressed recombination. Here we compare genome sequences from two N. tetrasperma strains of opposite mating type to determine whether structural rearrangements are associated with the nonrecombining region and to examine the effect of suppressed recombination for the evolution of the genes within it. We find a series of three inversions encompassing the majority of the region of suppressed recombination and provide evidence for two different types of rearrangement mechanisms: the recently proposed mechanism of inversion via staggered single-strand breaks as well as ectopic recombination between transposable elements. In addition, we show that the N. tetrasperma mat a mating-type region appears to be accumulating deleterious substitutions at a faster rate than the other mating type (mat A) and thus may be in the early stages of degeneration.

  20. Systematic gene deletions evidences that laccases are involved in several stages of wood degradation in the filamentous fungus Podospora anserina.

    Science.gov (United States)

    Xie, Ning; Chapeland-Leclerc, Florence; Silar, Philippe; Ruprich-Robert, Gwenaël

    2014-01-01

    Transformation of plant biomass into biofuels may supply environmentally friendly alternative biological sources of energy. Laccases are supposed to be involved in the lysis of lignin, a prerequisite step for efficient breakdown of cellulose into fermentable sugars. The role in development and plant biomass degradation of the nine canonical laccases belonging to three different subfamilies and one related multicopper oxidase of the Ascomycota fungus Podospora anserina was investigated by targeted gene deletion. The 10 genes were inactivated singly, and multiple mutants were constructed by genetic crosses. lac6(Δ), lac8(Δ) and mco(Δ) mutants were significantly reduced in their ability to grow on lignin-containing materials, but also on cellulose and plastic. Furthermore, lac8(Δ), lac7(Δ), mco(Δ) and lac6(Δ) mutants were defective towards resistance to phenolic substrates and H2 O2 , which may also impact lignocellulose breakdown. Double and multiple mutants were generally more affected than single mutants, evidencing redundancy of function among laccases. Our study provides the first genetic evidences that laccases are major actors of wood utilization in a fungus and that they have multiple roles during this process apart from participation in lignin lysis.

  1. Functions and regulation of the Nox family in the filamentous fungus Podospora anserina: a new role in cellulose degradation.

    Science.gov (United States)

    Brun, Sylvain; Malagnac, Fabienne; Bidard, Frédérique; Lalucque, Hervé; Silar, Philippe

    2009-10-01

    NADPH oxidases are enzymes that produce reactive oxygen species. Studies in mammals, plants and fungi have shown that they play important roles in differentiation, defence, host/pathogen interaction and mutualistic symbiosis. In this paper, we have identified a Podospora anserina mutant strain impaired for processes controlled by PaNox1 and PaNox2, the two Nox isoforms characterized in this model ascomycete. We show that the gene mutated is PaNoxR, the homologue of the gene encoding the regulatory subunit p67(phox), conserved in mammals and fungi, and that PaNoxR regulates both PaNox1 and PaNox2. Genome sequence analysis of P. anserina reveals that this fungus posses a third Nox isoform, PaNox3, related to human Nox5/Duox and plant Rboh. We have generated a knock-out mutant of PaNox3 and report that PaNox3 plays a minor role in P. anserina, if any. We show that PaNox1 and PaNox2 play antagonist roles in cellulose degradation. Finally, we report for the first time that a saprobic fungus, P. anserina, develops special cell structures dedicated to breach and to exploit a solid cellulosic substrate, cellophane. Importantly, as for similar structures present in some plant pathogens, their proper differentiation requires PaNox1, PaNox2, PaNoxR and the tetraspanin PaPls1.

  2. A novel single-stranded RNA virus isolated from a phytopathogenic filamentous fungus, Rosellinia necatrix, with similarity to hypo-like viruses

    Directory of Open Access Journals (Sweden)

    Rui eZhang

    2014-07-01

    Full Text Available Here we report a biological and molecular characterization of a novel positive-sense RNA virus isolated from a field isolate (NW10 of a filamentous phytopathogenic fungus, the white root rot fungus that is designated as Rosellinia necatrix fusarivirus 1 (RnFV1. A recently developed technology using zinc ions allowed us to transfer RnFV1 to two mycelially incompatible Rosellinia necatrix strains. A biological comparison of the virus-free and -recipient isogenic fungal strains suggested that RnFV1 infects latently and thus has no potential as a virocontrol agent. The virus has an undivided positive-sense RNA genome of 6286 nucleotides excluding a poly (A tail. The genome possesses two non-overlapping open reading frames (ORFs: a large ORF1 that encodes polypeptides with RNA replication functions and a smaller ORF2 that encodes polypeptides of unknown function. A lack of coat protein genes was suggested by the failure of virus particles from infected mycelia. No evidence was obtained by Northern analysis or classical 5'-RACE for the presence of subgenomic RNA for the downstream ORF. Sequence similarities were found in amino-acid sequence between RnFV1 putative proteins and counterparts of a previously reported mycovirus, Fusarium graminearum virus 1 (FgV1. Interestingly, several related sequences were detected by BLAST searches of independent transcriptome assembly databases one of which probably represents an entire virus genome. Phylogenetic analysis based on the conserved RNA-dependent RNA polymerase showed that RnFV1, FgV1, and these similar sequences are grouped in a cluster distinct from distantly related hypoviruses. It is proposed that a new taxonomic family termed Fusariviridae be created to include RnFV1and FgV1.

  3. A protein kinase C-encoding gene, pkcA, is essential to the viability of the filamentous fungus Aspergillus nidulans.

    Science.gov (United States)

    Ichinomiya, Masayuki; Uchida, Hirotaka; Koshi, Yukako; Ohta, Akinori; Horiuchi, Hiroyuki

    2007-11-01

    A protein kinase C (PKC)-encoding gene (pkcA) was isolated from the filamentous fungus Aspergillus nidulans. Although we attempted to isolate pkcA deletion mutants, we obtained only heterokaryons that had both DeltapkcA and pkcA(+) nuclei. Conidia produced by the heterokaryon germinated. The germ tubes, however, lysed frequently and no colony formation was observed, indicating that the pkcA gene is essential to the viability of A. nidulans. We constructed conditional mutants (alcA(p)-pkcA mutants) that expressed pkcA under the control of the alcA promoter (alcA(p)). Under alcA(p)-repressing conditions, their colonies were smaller than those of the wild-type strains and their hyphae lysed frequently. These phenotypes were not remedied under moderate- or high-osmolarity conditions; the growth defect deteriorated further under the latter. Under alcA(p)-inducing conditions, the alcA(p)-pkcA mutants also showed growth-sensitivity to cell wall destabilizing agents. These results indicate that pkcA plays an important role in the maintenance of cell integrity.

  4. Uncovering the genome-wide transcriptional responses of the filamentous fungus Aspergillus niger to lignocellulose using RNA sequencing.

    Directory of Open Access Journals (Sweden)

    Stéphane Delmas

    Full Text Available A key challenge in the production of second generation biofuels is the conversion of lignocellulosic substrates into fermentable sugars. Enzymes, particularly those from fungi, are a central part of this process, and many have been isolated and characterised. However, relatively little is known of how fungi respond to lignocellulose and produce the enzymes necessary for dis-assembly of plant biomass. We studied the physiological response of the fungus Aspergillus niger when exposed to wheat straw as a model lignocellulosic substrate. Using RNA sequencing we showed that, 24 hours after exposure to straw, gene expression of known and presumptive plant cell wall-degrading enzymes represents a huge investment for the cells (about 20% of the total mRNA. Our results also uncovered new esterases and surface interacting proteins that might form part of the fungal arsenal of enzymes for the degradation of plant biomass. Using transcription factor deletion mutants (xlnR and creA to study the response to both lignocellulosic substrates and low carbon source concentrations, we showed that a subset of genes coding for degradative enzymes is induced by starvation. Our data support a model whereby this subset of enzymes plays a scouting role under starvation conditions, testing for available complex polysaccharides and liberating inducing sugars, that triggers the subsequent induction of the majority of hydrolases. We also showed that antisense transcripts are abundant and that their expression can be regulated by growth conditions.

  5. The influence of some factors on β-1,4-xylanase activity of the filamentous fungus Trichoderma reesei QM9414

    Directory of Open Access Journals (Sweden)

    Alexandru Manoliu

    2012-03-01

    Full Text Available The mesophyllic fungus Trichoderma reesei (anamorph to Hypocrea jecorina is an important biotechnological tool, known for its ability to secrete large quantities of hydrolytic enzymes. Renewable biomass, such as agricultural and forest wastes are used to produce microbial enzymes in various industrial processes such as food, feed and bioethanol industries. In raw biomass materials, such as wheat straws, barley straws and maize stalks, the main polysaccharide is cellulose which is closely associated with hemicelluloses like xylan, manan and xyloguclan. In consequence, the hydrolysis of these materials requires the concerted action of several enzymes, namely cellulases and xylanases. Endo-xylanase (endo-1,4--xylanase, EC 3.2.1.8 is the key enzyme involved in xylan hydrolysis, the mainhemicellulosic component of plant cell walls. The metabolic activity and enzyme productivity of Trichoderma reesei isinfluenced by various environmental conditions. In this context, we analysed the effect of pH, cultivation period, thenature of the substrate used and the nitrogen source on enzymatic activity. The maximum xylanase yield was recorded at a initial pH of 4 (116.189 IU/ml for barley and 5 for wheat (88.578 IU/ml, respectively maize (116.583 IU/ml. The bestsubstrate for endo-xylanase activity was maize stalks (90.446 IU/ml at a a concentration of 30g/L.

  6. Comparative transcriptomic analysis of the heat stress response in the filamentous fungus Metarhizium anisopliae using RNA-Seq.

    Science.gov (United States)

    Wang, Zhang-Xun; Zhou, Xia-Zhi; Meng, Hui-Min; Liu, Yu-Jun; Zhou, Quan; Huang, Bo

    2014-06-01

    The entomopathogenic fungus Metarhizium anisopliae is widely used for biological control of a variety of insect pests. The effectiveness of the microbial pest control agent, however, is limited by poor thermotolerance. The molecular mechanism underlying the response to heat stress in the conidia of entomopathogenic fungi remains unclear. Here, we conducted high-throughput RNA-Seq to analyze the differential gene expression between control and heat treated conidia of M. anisopliae at the transcriptome level. RNA-Seq analysis generated 6,284,262 and 5,826,934 clean reads in the control and heat treated groups, respectively. A total of 2,722 up-regulated and 788 down-regulated genes, with a cutoff of twofold change, were identified by expression analysis. Among these differentially expressed genes, many were related to metabolic processes, biological regulation, cellular processes and response to stimuli. The majority of genes involved in endocytic pathways, proteosome pathways and regulation of autophagy were up-regulated, while most genes involved in the ribosome pathway were down-regulated. These results suggest that these differentially expressed genes may be involved in the heat stress response in conidia. As expected, significant changes in expression levels of genes encoding heat shock proteins and proteins involved in trehalose accumulation were observed in conditions of heat stress. These results expand our understanding of the molecular mechanisms of the heat stress response of conidia and provide a foundation for future investigations.

  7. Cytoplasmic continuity revisited: closure of septa of the filamentous fungus Schizophyllum commune in response to environmental conditions.

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    Arend F van Peer

    Full Text Available BACKGROUND: Mycelia of higher fungi consist of interconnected hyphae that are compartmentalized by septa. These septa contain large pores that allow streaming of cytoplasm and even organelles. The cytoplasm of such mycelia is therefore considered to be continuous. METHODOLOGY/PRINCIPAL FINDINGS: Here, we show by laser dissection that septa of Schizophyllum commune can be closed depending on the environmental conditions. The most apical septum of growing hyphae was open when this basidiomycete was grown in minimal medium with glucose as a carbon source. In contrast, the second and the third septum were closed in more than 50% and 90% of the cases, respectively. Interestingly, only 24 and 37% of these septa were closed when hyphae were growing in the absence of glucose. Whether a septum was open or closed also depended on physical conditions of the environment or the presence of toxic agents. The first septum closed when hyphae were exposed to high temperature, to hypertonic conditions, or to the antibiotic nourseothricin. In the case of high temperature, septa opened again when the mycelium was placed back to the normal growth temperature. CONCLUSIONS/SIGNIFICANCE: Taken together, it is concluded that the septal pores of S. commune are dynamic structures that open or close depending on the environmental conditions. Our findings imply that the cytoplasm in the mycelium of a higher fungus is not continuous per se.

  8. Hydrogenosomes in the anaerobic fungus Neocallimastix frontalis have a double membrane but lack an associated organelle genome

    NARCIS (Netherlands)

    van der Giezen, M; Sjollema, K.A; Artz, R.R.E.; Alkema, W.; Prins, R.A

    1997-01-01

    The presence of hydrogenosomes in phylogenetically distinct anaerobic eukaryotes implies that they have been acquired independently, and previously reported differences in ultrastructure among taxa have suggested that some hydrogenosomes have different origins. Of particular interest are reports tha

  9. Long-distance translocation of protein during morphogenesis of the fruiting body in the filamentous fungus, Agaricus bisporus.

    Directory of Open Access Journals (Sweden)

    Benjamin M Woolston

    Full Text Available Commercial cultivation of the mushroom fungus, Agaricus bisporus, utilizes a substrate consisting of a lower layer of compost and upper layer of peat. Typically, the two layers are seeded with individual mycelial inoculants representing a single genotype of A. bisporus. Studies aimed at examining the potential of this fungal species as a heterologous protein expression system have revealed unexpected contributions of the mycelial inoculants in the morphogenesis of the fruiting body. These contributions were elucidated using a dual-inoculant method whereby the two layers were differientially inoculated with transgenic β-glucuronidase (GUS and wild-type (WT lines. Surprisingly, use of a transgenic GUS line in the lower substrate and a WT line in the upper substrate yielded fruiting bodies expressing GUS activity while lacking the GUS transgene. Results of PCR and RT-PCR analyses for the GUS transgene and RNA transcript, respectively, suggested translocation of the GUS protein from the transgenic mycelium colonizing the lower layer into the fruiting body that developed exclusively from WT mycelium colonizing the upper layer. Effective translocation of the GUS protein depended on the use of a transgenic line in the lower layer in which the GUS gene was controlled by a vegetative mycelium-active promoter (laccase 2 and β-actin, rather than a fruiting body-active promoter (hydrophobin A. GUS-expressing fruiting bodies lacking the GUS gene had a bonafide WT genotype, confirmed by the absence of stably inherited GUS and hygromycin phosphotransferase selectable marker activities in their derived basidiospores and mycelial tissue cultures. Differientially inoculating the two substrate layers with individual lines carrying the GUS gene controlled by different tissue-preferred promoters resulted in up to a ∼3.5-fold increase in GUS activity over that obtained with a single inoculant. Our findings support the existence of a previously undescribed

  10. Interaction between TATA-Binding Protein (TBP and Multiprotein Bridging Factor-1 (MBF1 from the Filamentous Insect Pathogenic Fungus Beauveria bassiana.

    Directory of Open Access Journals (Sweden)

    Chi Song

    Full Text Available TATA-binding protein (TBP is a ubiquitous component of eukaryotic transcription factors that acts to nucleate assembly and position pre-initiation complexes. Multiprotein bridging factor 1 (MBF1 is thought to interconnect TBP with gene specific transcriptional activators, modulating transcriptional networks in response to specific signal and developmental programs. The insect pathogen, Beauveria bassiana, is a cosmopolitan fungus found in most ecosystems where it acts as an important regulator of insect populations and can form intimate associations with certain plants. In order to gain a better understanding of the function of MBF1 in filamentous fungi, its interaction with TBP was demonstrated. The MBF1 and TBP homologs in B. bassiana were cloned and purified from a heterologous E. coli expression system. Whereas purified BbTBP was shown to be able to bind oligonucleotide sequences containing the TATA-motif (Kd ≈ 1.3 nM including sequences derived from the promoters of the B. bassiana chitinase and protease genes. In contrast, BbMBF1 was unable to bind to these same target sequences. However, the formation of a ternary complex between BbMBF1, BbTBP, and a TATA-containing target DNA sequence was seen in agarose gel electrophoretic mobility shift assays (EMSA. These data indicate that BbMBF1 forms direct interactions with BbTBP, and that the complex is capable of binding to DNA sequences containing TATA-motifs, confirming that BbTBP can link BbMBF1 to target sequences as part of the RNA transcriptional machinery in fungi.

  11. Genotoxicity of the cyclo-oxygenase-inhibitor sulindac sulfide in the filamentous fungus Aspergillus nidulans Genotoxicidade de sulfeto de sulindaco em Aspergillus nidulans

    Directory of Open Access Journals (Sweden)

    Claudinéia Conationi da Silva Franco

    2007-09-01

    Full Text Available Sulindac sulfide is a non-steroidal anti-inflammatory drug (NSAID with chemopreventive effect on human cancer cells. Due to the involvement of the somatic recombination in the carcinogenic process, sulindac sulfide's recombinogenic potential was evaluated by the Homozygotization Index (HI in the filamentous fungus Aspergillus nidulans. The drug's recombinogenic potential was evaluated by its capacity to induce homozygosis of recessive genes from heterozygous diploid cells. Sulindac sulfide at 175 and 350 µM concentrations induced mitotic recombination in A. nidulans diploid cells, with HI values for genetic markers higher than 2.0, and significantly different from control HI values. The recombinogenic effect of NSAID was related to the induction of DNA strand breaks and cell cycle alterations. Sulindac sulfide's carcinogenic potential was also discussed.Sulfeto de sulindaco é um antiinflamatório não-esteroidal com efeitos quimiopreventivos em cânceres humanos. O presente estudo teve como objetivo avaliar o potencial recombinagênico do sulfeto de sulindaco em células diplóides de Aspergillus nidulans. O efeito recombinagênico da droga foi demonstrado através da homozigotização de genes recessivos, previamente presentes em heterozigose. Os valores de HI (Índice de Homozigotização para diferentes marcadores genéticos apresentaram-se maiores do que 2,0 e significativamente diferentes dos valores obtidos em sulfeto de sulindaco ausência da droga (controle. O potencial recombinagênico do sulfeto de sulindaco foi associado à indução de quebras na molécula do DNA e a alterações no ciclo celular. O potencial carcinogênico do sulfeto de sulindaco foi discutido no presente trabalho.

  12. The Nematicidal Spectrum of Bio-nematicides from Filamentous Fungus Sr18%Sr18生防制剂的杀线虫谱研究

    Institute of Scientific and Technical Information of China (English)

    李平; 田阳; 高丙利; 孙建华

    2012-01-01

    为检测Sr18生防制剂的杀线虫谱,通过室内法测定了Sr18的4种不同调配制剂S01-S04对南方根结线虫、大豆孢囊线虫和松材线虫的作用效果.结果表明:4种生防调配制剂对南方根结线虫的致死效果最强,稀释至8倍的校正死亡率均达到100%;对大豆孢囊线虫,生防制剂S01和S03(原始pH制剂)16倍稀释液的校正死亡率均可达到85%以上;而对松材线虫的致死率高的是S02和S04(中性pH制剂),8倍稀释液仍可达到100%.实验证实Sr18生防制剂是一种有效的广谱生物源杀线剂,在重要植物寄生线虫病害的生物防治方面具有广阔的应用前景.%For finding out the nematicidal spectrum of bio-nematicides from filamentous fungus Syncephalastrum racemosum (Sr18), in-vitro methods were developed to test the four different preparations of bio-nematicides, S01-S04, affecting nematode mobility of three nematodes including root knot nematode (RKN), soybean cyst nematode (SCN) and pine wood nematode (PWN). A serious of acute toxicity tests exhibited that the bio-nematicides were effective strongly to RKN, Meloidogyne incognita, and all of 8x diluted concentrations had corrected mortality of 100% differing from CK significantly; to SCN, Heterodera glycines, 16xdilution of S01 and S03 (the two nematicides with original pH) had corrected mortality of above 85%; on the contrary with SCN, S02 and S04 (the two neutral samples) had high nematicidal effects on PWN, Bursaphelenchus xylophilus, 100% corrected mortality from original concentrations to those at 8 x diluted. Bio-nematicides from Srl8 showed good effects on the three species of nematodes which had effective broad-spectrum biological nematicides, and would had the widespread application of several major plant-parasitic nematodes.

  13. Study on Anaerobic Digestion of Black Fungus Production Residue%黑木耳生产残留物厌氧消化试验研究

    Institute of Scientific and Technical Information of China (English)

    苏珊; 林聪; 姜文腾; 王阳

    2011-01-01

    Anaerobic fermentations of black fungus production residue were conducted at fermentation TS concentration of 6% ,9% , 12% , and 15% in this sdudy. Batch fermentation was adopted. The gas production, CODCr, TS and VS of influent and effluent, crude fiber, pH, and TKN were determined and analyzed. The result showed that acidification would be appeared during the anaerobic fermentation if the inoculum was insufficient. The highest accumulated gas production (14876 mL) was obtained when the TS concentration of fermentation was 15% , which was 23. 90% ,11. 12% and 11.26% higher than the fermentation TS concentration of 6% ,9% and 12% , respectively. The CODCr concentration of effluent were 31.45% ,33.75% ,36.67% and 36.53% for the fermentation TS concentration of 6% ,9% , 12% , and 15% , respectively. Averagely 35% of organic matter in black fungus production residue could be utilized. Fermentation concen--tration of 15% obtained the highest TS and VS degradation rate, which were 43.82% and 47.42% respectively. The crude fiber degradation rates were almost similar for all fermentation concentration, about 57%. The TKN concentrations in effluent were increased for all fermentation concentration.%文章研究了利用厌氧消化技术处理黑木耳生产残留物.采用序批式厌氧消化方式,分别对pH值,产气量,CODCr,进出料TS,VS,粗纤维、凯氏氮等进行测试分析.试验表明:以黑木耳生产残留物为厌氧消化原料,若接种物不足,易产生酸化.厌氧消化料液浓度(TS)15%时,累计总产气量最高,为14876 mL,分别比厌氧消化料液浓度6%,9%和12%时高出23.90%,11.12%和11.26%,说明在实验条件下,黑木耳生产残留物厌氧消化的浓度越高,产气越多.4组处理的出料CODCr浓度相对于进料时分别降低了31.45%,33.75%,36.67%和36.53%.得出黑木耳生产残留物中可被厌氧微生物降解的有机物含量平均为35%左右.厌氧消化液浓度15%时的TS和VS

  14. Selection arena in Aspergillus nidulans : early progeny choice in a filamentous fungus = Selectie arena in Aspergillus nidulans : vroege selectie van nakomelingen in een filamenteuse schimmel

    NARCIS (Netherlands)

    Bruggeman, J.

    2003-01-01

    Keywords:selection arena, progeny choice, Aspergillus nidulans , fungus, spores, ascospore, conidiospore, asexual, sexual, fruiting body, cleistothecium, zygote, dikaryon, self-sterility, self-fertility, mutation accumulation, fitness,

  15. Interaction between TATA-Binding Protein (TBP) and Multiprotein Bridging Factor-1 (MBF1) from the Filamentous Insect Pathogenic Fungus Beauveria bassiana

    OpenAIRE

    Chi Song; Almudena Ortiz-Urquiza; Sheng-Hua Ying; Jin-Xia Zhang; Nemat O Keyhani

    2015-01-01

    TATA-binding protein (TBP) is a ubiquitous component of eukaryotic transcription factors that acts to nucleate assembly and position pre-initiation complexes. Multiprotein bridging factor 1 (MBF1) is thought to interconnect TBP with gene specific transcriptional activators, modulating transcriptional networks in response to specific signal and developmental programs. The insect pathogen, Beauveria bassiana, is a cosmopolitan fungus found in most ecosystems where it acts as an important regula...

  16. Adaptive alterations in the fatty acids composition under induced oxidative stress in heavy metal-tolerant filamentous fungus Paecilomyces marquandii cultured in ascorbic acid presence.

    Science.gov (United States)

    Słaba, Mirosława; Gajewska, Ewa; Bernat, Przemysław; Fornalska, Magdalena; Długoński, Jerzy

    2013-05-01

    The ability of the heavy metal-tolerant fungus Paecilomyces marquandii to modulate whole cells fatty acid composition and saturation in response to IC50 of Cd, Pb, Zn, Ni, and Cu was studied. Cadmium and nickel caused the most significant growth reduction. In the mycelia cultured with all tested metals, with the exception of nickel, a rise in the fatty acid unsaturation was noted. The fungus exposure to Pb, Cu, and Ni led to significantly higher lipid peroxidation. P. marquandii incubated in the presence of the tested metals responded with an increase in the level of linoleic acid and escalation of electrolyte leakage. The highest efflux of electrolytes was caused by lead. In these conditions, the fungus was able to bind up to 100 mg g(-1) of lead, whereas the content of the other metals in the mycelium was significantly lower and reached from 3.18 mg g(-1) (Cu) to 15.21 mg g(-1) (Zn). Additionally, it was shown that ascorbic acid at the concentration of 1 mM protected fungal growth and prevented the changes in the fatty acid composition and saturation but did not alleviate lipid peroxidation or affect the increased permeability of membranes after lead exposure. Pro-oxidant properties of ascorbic acid in the copper-stressed cells manifested strong growth inhibition and enhanced metal accumulation as a result of membrane damage. Toxic metals action caused cellular modulations, which might contributed to P. marquandii tolerance to the studied metals. Moreover, these changes can enhance metal removal from contaminated environment.

  17. The transcription factor Ste12 mediates the regulatory role of the Tmk1 MAP kinase in mycoparasitism and vegetative hyphal fusion in the filamentous fungus Trichoderma atroviride.

    Science.gov (United States)

    Gruber, Sabine; Zeilinger, Susanne

    2014-01-01

    Mycoparasitic species of the fungal genus Trichoderma are potent antagonists able to combat plant pathogenic fungi by direct parasitism. An essential step in this mycoparasitic fungus-fungus interaction is the detection of the fungal host followed by activation of molecular weapons in the mycoparasite by host-derived signals. The Trichoderma atroviride MAP kinase Tmk1, a homolog of yeast Fus3/Kss1, plays an essential role in regulating the mycoparasitic host attack, aerial hyphae formation and conidiation. However, the transcription factors acting downstream of Tmk1 are hitherto unknown. Here we analyzed the functions of the T. atroviride Ste12 transcription factor whose orthologue in yeast is targeted by the Fus3 and Kss1 MAP kinases. Deletion of the ste12 gene in T. atroviride not only resulted in reduced mycoparasitic overgrowth and lysis of host fungi but also led to loss of hyphal avoidance in the colony periphery and a severe reduction in conidial anastomosis tube formation and vegetative hyphal fusion events. The transcription of several orthologues of Neurospora crassa hyphal fusion genes was reduced upon ste12 deletion; however, the Δste12 mutant showed enhanced expression of mycoparasitism-relevant chitinolytic and proteolytic enzymes and of the cell wall integrity MAP kinase Tmk2. Based on the comparative analyses of Δste12 and Δtmk1 mutants, an essential role of the Ste12 transcriptional regulator in mediating outcomes of the Tmk1 MAPK pathway such as regulation of the mycoparasitic activity, hyphal fusion and carbon source-dependent vegetative growth is suggested. Aerial hyphae formation and conidiation, in contrast, were found to be independent of Ste12.

  18. Nail Fungus

    Science.gov (United States)

    ... problems, a weakened immune system or, in children, Down syndrome A severe case of nail fungus can be ... possibly effective in treating nail fungus, but more study is needed. ... and file down thickened areas. Wear socks that absorb sweat. Fabrics ...

  19. IDC1, a pezizomycotina-specific gene that belongs to the PaMpk1 MAP kinase transduction cascade of the filamentous fungus Podospora anserina.

    Science.gov (United States)

    Jamet-Vierny, Corinne; Debuchy, Robert; Prigent, Magali; Silar, Philippe

    2007-12-01

    Components involved in the activation of the MAPK cascades in filamentous fungi are not well known. Here, we provide evidence that IDC1, a pezizomycotina-specific gene is involved along with the PaNox1 NADPH oxidase in the nuclear localization of the PaMpk1 MAP kinase, a prerequisite for MAPK activity. Mutants of IDC1 display the same phenotypes as mutants in PaNox1 and PaMpk1, i.e., lack of pigment and of aerial hyphae, female sterility, impairment in hyphal interference and inability to develop Crippled Growth cell degeneration. As observed for the PaNox1 mutant, IDC1 mutants are hypostatic to PaMpk1 mutants. IDC1 seems to play a key role in sexual reproduction. Indeed, fertility is diminished in strains with lower level of IDC1. In strains over-expressing IDC1, protoperithecia reach a later stage of development towards perithecia without fertilization; however, upon fertilization maturation of fertile perithecia is diminished and delayed. In addition, heterokaryon construction shows that IDC1 is necessary together with PaNox1 in the perithecial envelope but not in the dikaryon resulting from fertilization.

  20. Furfural degradation by filamentous fungus Amorphotheca resinae ZN1%丝状真菌Amorphotheca resinae ZN1的糠醛降解代谢分析

    Institute of Scientific and Technical Information of China (English)

    王晓凤; 张建; 辛秀娟; 鲍杰

    2012-01-01

    Some degradation products from lignocellulose pretreatment strongly inhibit the activities of cellulolytic enzymes and ethanol fermentation strains, thus the efficient removal of the inhibitor substances ("detoxification") is the inevitable step for the biotransformation processes. In this study, the biological detoxification of furfural by a newly isolated fungus, Amorphotheca resinae ZN1, was studied and the metabolic pathways of furfural degradation was analyzed. The metabolic pathway of furfural degradation in A. resinae ZN1 was described as follows: first, furfural was quickly converted into the low toxic furfuryl alcohol; then the furfuryl alcohol was gradually converted into furfural again but under the low concentration under aerobic condition, which was not lethal to the growth of the fungi; furfural continued to be oxidized to furoic acid by A. resinae ZN1. It is likely that furoic acid was further degraded in the TCA cycle to complete the biological degradation of furfural. The present study provided the important experimental basis for speeding up the biodetoxification of furfural by A. resinae ZN1 and the rate-limiting step in the lignocellulose biotransformation to ethanol.%木质纤维素在预处理过程产生的降解产物对后续的酶水解和微生物发酵过程产生了强烈的抑制.因此,这些抑制物的脱除即所谓的“脱毒”步骤是正常进行后续酶解和发酵的前提条件.我们对本实验室筛选的丝状真菌Amorphotheca resinae ZN1的糠醛的代谢路径进行了研究.丝状真菌A.resinae ZN1转化糠醛的降解代谢途径可以简述为:糠醛首先快速地转化为毒性较低的糠醇;在有氧条件下,糠醇又再度生成不致对微生物产生危害的低浓度糠醛,糠醛继续氧化为糠酸.推测糠酸可能继续进入TCA循环,进而完成糠醛的完全降解.研究结果为将来加快丝状真菌A.resinae ZN1生物脱毒速率、改善木质纤维素生物转化的限速步骤提供了重要的实验依据.

  1. Identification and characterization of filamentous fungus during xylose fermentation for ethanol production%木糖发酵产乙醇丝状真菌的鉴定及发酵特性

    Institute of Scientific and Technical Information of China (English)

    范金霞; 杨谦; 姚琳; 陈刚

    2011-01-01

    At present,yeast is the main microorganism involved in ethanol production using xylose as carbon source.The filamentous fungi have been less studied compared to yeast.Duchenne tube and ethanol yield assay methods were applied to screen different microbes for xylose fermentation.The microorganism producing the highest amount of ethanol was identified by microscopy and 18s rRNA amplification and analysis.Fermentation assays of this microorganism were studied by the Potassium dichromate method.The screening results showed that the organism code named cs-28 was Fusarium oxysporum.It was found that this fungus could ferment xylose,glucose,sucrose and corn stalk to produce ethanol.The optimal nitrogen source was yeast extract.The ethanol production rate was highest at initial pH 6.0 and 30 ℃,when initial xylose concentration was 20 g·L-1.Thus,cs-28 can be used as a new strain for transformation of cellulose materials to ethanol.Moreover,characterization of cs-28 on xylose fermentation can be applied in technological advancement.%针对目前对丝状真菌的木糖发酵研究较少的现状,应用杜氏管发酵法初筛和发酵测定法复筛对不同环境的土壤样品进行菌株的筛选,并采用显微镜观察和18S rRNA序列扩增分析对菌种进行鉴定;用重铬酸钾法对菌株的发酵特性进行研究.结果表明:筛选到一株能发酵木糖的丝状真菌,命名为cs-28;经形态学和生物学鉴定为尖孢镰刀菌(Fusarium oxysporum);它不仅能发酵木糖,同时也能利用葡萄糖、蔗糖和玉米秸秆等多种发酵碳源;其最适氮源为酵母提取物;在温度为30℃、初始pH值为6.0、初始木糖质量浓度为20 g·L-

  2. Influence of an aerobic fungus grown on solid culture on ruminal degradability and on a mixture culture of anaerobic cellulolytic bacteria.

    Science.gov (United States)

    Hernández-Díaz, R; Pimentel-González, D J; Figueira, A C; Viniegra-González, G; Campos-Montiel, R G

    2010-06-01

    In this work, the effect of a solid fungal culture of Aspergillus niger (An) grown on coffee pulp on the in situ ruminal degradability (RD) of corn stover was evaluated. In addition, the effect of its extracts on the in vitro dry matter disappearance (IVDMD) and on a mixed culture of anaerobic cellulolytic bacteria (MCACB) was also investigated. The solid ferment was a crude culture of An, grown on coffee pulp. Regarding in situ RD, a significant difference (p < 0.05) was found between treatment with 200 g/day of the solid culture and control (no solid culture added) on dry matter, crude protein and neutral detergent fibre on RD. All the water extracts (pH 4, 7 and 10) enhanced IVDMD and stimulated the cellulolytic activity on a MCACB. Ultrafiltration results showed that active compounds with a molecular weight lower than 30 kDa were responsible for the effect on MCACB. Such results suggest that the effects of the solid An culture in RD are related to the presence of water soluble compounds having a molecular weight lower than 30 kDa.

  3. Fungus Amongus

    Science.gov (United States)

    Wakeley, Deidra

    2005-01-01

    This role-playing simulation is designed to help teach middle level students about the typical lifecycle of a fungus. In this interactive simulation, students assume the roles of fungi, spores, living and dead organisms, bacteria, and rain. As they move around a playing field collecting food and water chips, they discover how the organisms…

  4. Filamentous Fungi Fermentation

    DEFF Research Database (Denmark)

    Nørregaard, Anders; Stocks, Stuart; Woodley, John

    2014-01-01

    Filamentous fungi (including microorganisms such as Aspergillus niger and Rhizopus oryzae) represent an enormously important platform for industrial fermentation. Two particularly valuable features are the high yield coefficients and the ability to secrete products. However, the filamentous...

  5. Filamentation in Laser Wakefields

    Science.gov (United States)

    Los, Eva; Trines, Raoul; Silva, Luis; Bingham, Robert

    2016-10-01

    Laser filamentation instability is observed in plasma wakefields with sub-critical densities, and in high density inertial fusion plasmas. This leads to non-uniform acceleration or compression respectively. Here, we present simulation results on laser filamentation in plasma wakefields. The 2-D simulations are carried out using the particle-in-cell code Osiris. The filament intensity was found to increase exponentially before saturating. The maximum amplitude to which the highest intensity filament grew for a specific set of parameters was also recorded, and plotted against a corresponding parameter value. Clear, positively correlated linear trends were established between plasma density, transverse wavenumber k, laser pulse amplitude and maximum filament amplitude. Plasma density and maximum filament amplitude also showed a positive correlation, which saturated after a certain plasma density. Pulse duration and interaction length did not affect either filament intensity or transverse k value in a predictable manner. There was no discernible trend between pulse amplitude and filament width.

  6. White Fungus Soup

    Institute of Scientific and Technical Information of China (English)

    1994-01-01

    Ingredients: two pieces of white fungus, a handful of Chinese wolfberry fruit, dates, dried longan, lotus seeds and peanuts. Directions: 1. Soak the dried fungus in water, remove the roots and then cook. 2. Steep the Chinese wolfberry fruit, dates, dried longan, lotus seeds and peanuts in water for a while.

  7. Anaerobic bacteria

    Science.gov (United States)

    Brook I, Goldstein EJ. Diseases caused by non-spore forming anaerobic bacteria. In: Goldman L, Schafer AI, eds. Goldman's Cecil Medicine . 25th ed. Philadelphia, PA: Elsevier Saunders; 2015:chap 297. Stedman's Online ...

  8. Solar Features - Prominences and Filaments - Filaments

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Filaments are formed in magnetic loops that hold relatively cool, dense gas suspended above the surface of the Sun (David Hathaway/NASA)

  9. DNA-mediated transformation of the filamentous fungus Aspergillus nidulans.

    NARCIS (Netherlands)

    Wernars, K.

    1986-01-01

    Although transformation of S.   cerevisiae and N.crassa already could be achieved at the end of the seventies, positive results for A.nidulans had to await the isolation of useful selection markers. As soon as cloned fungal genes of homologous ( amd S

  10. Genomic islands in the pathogenic filamentous fungus Aspergillus fumigatus.

    Directory of Open Access Journals (Sweden)

    Natalie D Fedorova

    2008-04-01

    Full Text Available We present the genome sequences of a new clinical isolate of the important human pathogen, Aspergillus fumigatus, A1163, and two closely related but rarely pathogenic species, Neosartorya fischeri NRRL181 and Aspergillus clavatus NRRL1. Comparative genomic analysis of A1163 with the recently sequenced A. fumigatus isolate Af293 has identified core, variable and up to 2% unique genes in each genome. While the core genes are 99.8% identical at the nucleotide level, identity for variable genes can be as low 40%. The most divergent loci appear to contain heterokaryon incompatibility (het genes associated with fungal programmed cell death such as developmental regulator rosA. Cross-species comparison has revealed that 8.5%, 13.5% and 12.6%, respectively, of A. fumigatus, N. fischeri and A. clavatus genes are species-specific. These genes are significantly smaller in size than core genes, contain fewer exons and exhibit a subtelomeric bias. Most of them cluster together in 13 chromosomal islands, which are enriched for pseudogenes, transposons and other repetitive elements. At least 20% of A. fumigatus-specific genes appear to be functional and involved in carbohydrate and chitin catabolism, transport, detoxification, secondary metabolism and other functions that may facilitate the adaptation to heterogeneous environments such as soil or a mammalian host. Contrary to what was suggested previously, their origin cannot be attributed to horizontal gene transfer (HGT, but instead is likely to involve duplication, diversification and differential gene loss (DDL. The role of duplication in the origin of lineage-specific genes is further underlined by the discovery of genomic islands that seem to function as designated "gene dumps" and, perhaps, simultaneously, as "gene factories".

  11. Tremella with Edible Fungus

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    (Meiwei Shuang’er)Remove the tremella and edible fungus roots, clean and drain. Slice green peppers and carrots.Heat some oil in a wok, add tremella, edible fungus, green peppers and carrots, and clear stock, salt and sugar. Simmer for two minutes. Add MSG and pepper, remove to a plate, and serve.Features: Attractively black and white.Taste: Crisp and savory.

  12. Semiflexible filamentous composites

    NARCIS (Netherlands)

    Huisman, E.M.; Heussinger, C.; Storm, C.; Barkema, G.T.

    2010-01-01

    Inspired by the ubiquity of composite filamentous networks in nature, we investigate models of biopolymer networks that consist of interconnected floppy and stiff filaments. Numerical simulations carried out in three dimensions allow us to explore the microscopic partitioning of stresses and strains

  13. Proteomics of Filamentous Fungi

    NARCIS (Netherlands)

    Passel, van M.W.J.; Schaap, P.J.; Graaff, de L.H.

    2013-01-01

    Filamentous fungi, such as Aspergillus niger and Aspergillus oryzae traditionally have had an important role in providing enzymes and enzyme cocktails that are used in food industry. In recent years the genome sequences of many filamentous fungi have become available. This combined with technologica

  14. Tungsten Filament Fire

    Science.gov (United States)

    Ruiz, Michael J.; Perkins, James

    2016-01-01

    We safely remove the outer glass bulb from an incandescent lamp and burn up the tungsten filament after the glass is removed. This demonstration dramatically illustrates the necessity of a vacuum or inert gas for the environment surrounding the tungsten filament inside the bulb. Our approach has added historical importance since the incandescent…

  15. Anaerobic biodegradability of macropollutants

    DEFF Research Database (Denmark)

    Angelidaki, Irini

    2002-01-01

    A variety of test procedures for determination of anaerobic biodegradability has been reported. This paper reviews the methods developed for determination of anaerobic biodegradability of macro-pollutants. Anaerobic biodegradability of micro-pollutants is not included. Furthermore, factors import...

  16. Antibiotic Resistance and Fungus

    Centers for Disease Control (CDC) Podcasts

    2017-02-28

    Dr. David Denning, President of the Global Action Fund for Fungal Infections and an infectious diseases clinician, discusses antimicrobial resistance and fungus.  Created: 2/28/2017 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 2/28/2017.

  17. Bacterial intermediate filaments

    DEFF Research Database (Denmark)

    Charbon, Godefroid; Cabeen, M.; Jacobs-Wagner, C.

    2009-01-01

    Crescentin, which is the founding member of a rapidly growing family of bacterial cytoskeletal proteins, was previously proposed to resemble eukaryotic intermediate filament (IF) proteins based on structural prediction and in vitro polymerization properties. Here, we demonstrate that crescentin...

  18. Femtosecond Laser Filamentation

    CERN Document Server

    Chin, See Leang

    2010-01-01

    Femtosecond Laser Filamentation gives a comprehensive review of the physics of propagation of intense femtosecond laser pulses in optical media (principally air) and the applications and challenges of this new technique. This book presents the modern understanding of the physics of femtosecond laser pulse propagation, including unusual new effects such as the self-transformation of the pulse into a white light laser pulse, intensity clamping, the physics of multiple filamentation and competition, and how filaments’ ability to melt glass leads to wave guide writing. The potential applications of laser filamentation in atmospheric sensing and the generation of other electromagnetic pulses from the UV to the radio frequency are treated, together with possible future challenges in the excitation of super-excited states of molecules. Exciting new phenomena such as filament induced ultrafast birefringence and the excitation of molecular rotational wave packets and their multiple revivals in air (gases) will also ...

  19. Blistering of viscoelastic filaments

    CERN Document Server

    Sattler, R; Wagner, C

    2007-01-01

    When a dilute polymer solution experiences capillary thinning, it forms an almost uniformly cylindrical thread, which we study experimentally. In the last stages of thinning, when polymers have become fully stretched, the filament becomes prone to instabilities, of which we describe two: A novel "breathing" instability, originating from the edge of the filament, and a sinusoidal instability in the interior, which ultimately gives rise to a "blistering" pattern of beads on the filament. We describe the linear instability with a spatial resolution of 80 nm in the disturbance amplitude. For sufficiently high polymer concentrations, the filament eventually separates out into a "solid" phase of entangled polymers, connected by fluid beads. A solid polymer fiber of about 100 nanometer thickness remains, which is essentially permanent.

  20. The chestnut blight fungus for studies on virus/host and virus/virus interactions: from a natural to a model host.

    Science.gov (United States)

    Eusebio-Cope, Ana; Sun, Liying; Tanaka, Toru; Chiba, Sotaro; Kasahara, Shin; Suzuki, Nobuhiro

    2015-03-01

    The chestnut blight fungus, Cryphonectria parasitica, is an important plant pathogenic ascomycete. The fungus hosts a wide range of viruses and now has been established as a model filamentous fungus for studying virus/host and virus/virus interactions. This is based on the development of methods for artificial virus introduction and elimination, host genome manipulability, available host genome sequence with annotations, host mutant strains, and molecular tools. Molecular tools include sub-cellular distribution markers, gene expression reporters, and vectors with regulatable promoters that have been long available for unicellular organisms, cultured cells, individuals of animals and plants, and certain filamentous fungi. A comparison with other filamentous fungi such as Neurospora crassa has been made to establish clear advantages and disadvantages of C. parasitica as a virus host. In addition, a few recent studies on RNA silencing vs. viruses in this fungus are introduced.

  1. Actinomycetes inhibit filamentous fungi from the cuticle of Acromyrmex leafcutter ants.

    Science.gov (United States)

    Dângelo, Rômulo Augusto Cotta; de Souza, Danival José; Mendes, Thais Demarchi; Couceiro, Joel da Cruz; Lucia, Terezinha Maria Castro Della

    2016-03-01

    Actinomycetes bacteria associated with leafcutter ants produce secondary metabolites with antimicrobial properties against Escovopsis, a fungus specialized in attacking the gardens of fungus-growing ants, which denies the ants their food source. Because previous studies have used fungi isolated from fungus gardens but not from ant integument, the aims of the present study were to isolate actinomycetes associated with the cuticle of the Acromyrmex spp. and to quantify their inhibition abilities against the filamentous fungal species carried by these ants. The results demonstrated that actinomycetes had varied strain-dependent effects on several filamentous fungal species in addition to antagonistic activity against Escovopsis. The strain isolated from Acromyrmex balzani was identified as a Streptomyces species, whereas the remaining isolates were identified as different strains belonging to the genus Pseudonocardia. These findings corroborate the hypothesis that actinomycetes do not act specifically against Escovopsis mycoparasites and may have the ability to inhibit other species of pathogenic fungi.

  2. 厌氧真菌内切-β-葡聚糖酶基因在里氏木霉中的重组与表达%Recombination and Expression of an Anaerobic Fungus Endo-β-Glucanase Gene in Trichoderma Reesei Cells

    Institute of Scientific and Technical Information of China (English)

    金欣; 夏黎明

    2011-01-01

    里氏木霉(Trichoderm reesei)是重要的纤维素酶生产菌,为了显著提高其产酶性能,拟利用分子生物学技术构建高产的基因工程菌株.将前期优化后的瘤胃厌氧真菌内切-β-葡聚糖酶基因af2置于里氏木霉纤维二糖水解酶Ⅰ强启动子Pcbh1(及其信号肽)和终止子Tcbh1之间,并进一步以pCAMBIA1300为载体骨架,构建成含潮霉素B抗性标记的重组质粒pCB-hF.以里氏木霉ZU-02为宿主,采用优化的根瘤农杆菌介导转化技术将重组质粒转入经萌发处理的分生孢子.以潮霉素B为抗性标记初筛到318个阳性转化子,进一步接种到以羧甲基纤维素钠为唯一碳源的筛选培养基上,复筛到8株生长较快的转化子.以重组转化子基因组DNA为模板,分别进行PCR检测,均可获得目的基因片段,表明厌氧真菌内切-β-葡聚糖酶基因已整合到里氏木霉的染色体DNA上.在摇瓶条件下,分别对8个重组转化子进行产酶试验,获得3个高产内切-β-葡聚糖酶活力的转化子.发酵培养96 h时,发酵液的内切-β-葡聚糖酶活力最高可达到126.3 IU.mL-1左右,是出发菌株的4.23倍.研究结果表明:厌氧真菌内切-β-争葡聚糖酶基因已在里氏木霉细胞中得到高效表达并实现了胞外分泌.%Trichoderma reesei is a good cellulase producer. In order to improve its enzyme production, molecular biology technology was adopted to obtain recombinant strain with high yields in this study. An optimized anaerobic fungus endo-β-glucanase gene af 2 was inserted between T.reesei strong promoter Pcbhl (including secreting signal peptide sequence) and terminator, further ligated to pCAMBIA1300 vector to construct a recombination plasmid pCB-hF with hygromycin B resistance marker. The plasmid pCB-hF was transformed into T. Reesei ZU-02 via an optimized Agrobacterium tumefaciens mediated transformation, with the germinated conidia as starting material. 318 positive transformants were screened by

  3. Anaerobic Thermophiles

    Directory of Open Access Journals (Sweden)

    Francesco Canganella

    2014-02-01

    Full Text Available The term “extremophile” was introduced to describe any organism capable of living and growing under extreme conditions. With the further development of studies on microbial ecology and taxonomy, a variety of “extreme” environments have been found and an increasing number of extremophiles are being described. Extremophiles have also been investigated as far as regarding the search for life on other planets and even evaluating the hypothesis that life on Earth originally came from space. The first extreme environments to be largely investigated were those characterized by elevated temperatures. The naturally “hot environments” on Earth range from solar heated surface soils and water with temperatures up to 65 °C, subterranean sites such as oil reserves and terrestrial geothermal with temperatures ranging from slightly above ambient to above 100 °C, to submarine hydrothermal systems with temperatures exceeding 300 °C. There are also human-made environments with elevated temperatures such as compost piles, slag heaps, industrial processes and water heaters. Thermophilic anaerobic microorganisms have been known for a long time, but scientists have often resisted the belief that some organisms do not only survive at high temperatures, but actually thrive under those hot conditions. They are perhaps one of the most interesting varieties of extremophilic organisms. These microorganisms can thrive at temperatures over 50 °C and, based on their optimal temperature, anaerobic thermophiles can be subdivided into three main groups: thermophiles with an optimal temperature between 50 °C and 64 °C and a maximum at 70 °C, extreme thermophiles with an optimal temperature between 65 °C and 80 °C, and finally hyperthermophiles with an optimal temperature above 80 °C and a maximum above 90 °C. The finding of novel extremely thermophilic and hyperthermophilic anaerobic bacteria in recent years, and the fact that a large fraction of them belong

  4. Characterization of HI Filaments

    Science.gov (United States)

    Lubar, Emily; Verschuur, Gerrit L.

    2017-01-01

    We characterized the properties of dramatic interstellar HI filaments to learn more about the dynamics and structure of such features. Using Gauss fitting software, we searched the Effelsburg-Bonn HI Survey data for indications of a simple twisting (toroidal) motion across these filaments. Instead, we found that the structure was more complicated than expected. Apparent angular widths of several filaments were measured using the Galactic Arecibo L-band Feed Array HI (GALFA-HI), Bonn, and Leident/Argentine/Bonn (LAB) surveys. Based on filament widths and other parameters, we conclude that magnetism is the dominant force opposing internal motion and maintaining the structure of these filaments. The apparent width as a function of beam width closely follows a relationship reported in 1993 for HI features in general. They tend to subtend an angle two times the beam width, suggesting that the features remain unresolved.The Arecibo Observatory is operated by SRI International under a cooperative agreement with the National Science Foundation (AST-1100968), and in alliance with Ana G. Méndez-Universidad Metropolitana, and the Universities Space Research Association. The Arecibo Observatory REU is funded under grant AST-1559849 to Universidad Metropolitana.

  5. Subhalo Accretion through Filaments

    Science.gov (United States)

    González, Roberto E.; Padilla, Nelson D.

    2016-09-01

    We track subhalo orbits of galaxy- and group-sized halos in cosmological simulations. We identify filamentary structures around halos and use these to define a sample of subhalos accreted from filaments, as well as a control sample of subhalos accreted from other directions. We use these samples to study differences in satellite orbits produced by filamentary accretion. Our results depend on host halo mass. We find that for low masses, subhalos accreted from filaments show ∼10% shorter lifetimes compared to the control sample, show a tendency toward more radial orbits, reach halo central regions earlier, and are more likely to merge with the host. For higher-mass halos this lifetime difference dissipates and even reverses for cluster-sized halos. This behavior appears to be connected to the fact that more massive hosts are connected to stronger filaments with higher velocity coherence and density, with slightly more radial subhalo orbits. Because subhalos tend to follow the coherent flow of the filament, it is possible that such thick filaments are enough to shield the subhalo from the effect of dynamical friction at least during their first infall. We also identify subhalo pairs/clumps that merge with one another after accretion. They survive as a clump for only a very short time, which is even shorter for higher subhalo masses, suggesting that the Magellanic Clouds and other Local group satellite associations may have entered the Milky Way virial radius very recently and probably are in their first infall.

  6. Aerogel-supported filament

    Science.gov (United States)

    Wuest, Craig R.; Tillotson, Thomas M.; Johnson, III, Coleman V.

    1995-01-01

    The present invention is a thin filament embedded in a low density aerogel for use in radiation detection instruments and incandescent lamps. The aerogel provides a supportive matrix that is thermally and electrically nonconductive, mechanically strong, highly porous, gas-permeable, and transparent to ionizing radiation over short distances. A low density, open-cell aerogel is cast around a fine filament or wire, which allows the wire to be positioned with little or no tension and keeps the wire in place in the event of breakage. The aerogel support reduces the stresses on the wire caused by vibrational, gravitational, electrical, and mechanical forces.

  7. Branching of keratin intermediate filaments.

    Science.gov (United States)

    Nafeey, Soufi; Martin, Ines; Felder, Tatiana; Walther, Paul; Felder, Edward

    2016-06-01

    Keratin intermediate filaments (IFs) are crucial to maintain mechanical stability in epithelial cells. Since little is known about the network architecture that provides this stiffness and especially about branching properties of filaments, we addressed this question with different electron microscopic (EM) methods. Using EM tomography of high pressure frozen keratinocytes, we investigated the course of several filaments in a branching of a filament bundle. Moreover we found several putative bifurcations in individual filaments. To verify our observation we also visualized the keratin network in detergent extracted keratinocytes with scanning EM. Here bifurcations of individual filaments could unambiguously be identified additionally to bundle branchings. Interestingly, identical filament bifurcations were also found in purified keratin 8/18 filaments expressed in Escherichia coli which were reassembled in vitro. This excludes that an accessory protein contributes to the branch formation. Measurements of the filament cross sectional areas showed various ratios between the three bifurcation arms. This demonstrates that intermediate filament furcation is very different from actin furcation where an entire new filament is attached to an existing filament. Instead, the architecture of intermediate filament bifurcations is less predetermined and hence consistent with the general concept of IF formation.

  8. The mitochondrial genome of the ethanol-metabolizing, wine cellar mold Zasmidium cellare is the smallest for a filamentous ascomycete

    Energy Technology Data Exchange (ETDEWEB)

    Goodwin, Stephen; McCorison, Cassandra B.; Cavaletto, Jessica R.; Culley, David E.; LaButti, Kurt M.; Baker, Scott E.; Grigoriev, Igor V.

    2016-05-20

    Fungi in the class Dothideomycetes often live in extreme environments or have unusual physiology. One of these, the wine cellar mold Zasmidium cellare, produces thick curtains of mycelial growth in cellars with high humidity, and its ability to metabolize volatile organic compounds including alcohols, esters and formaldehyde is thought to improve air quality. It grows slowly but appears to outcompete ordinarily faster-growing species under anaerobic conditions.Whether these abilities have affected its mitochondrial genome is not known.To fill this gap, its mitochondrial genome was assembled as part of a whole- genome shotgun-sequencing project.The circular-mapping mitochondrial genome of Z. cellare, at only 23,743 bp, is the smallest yet reported for a filamentous fungus.It contains the complete set of 14 protein-coding genes seen typically in other filamentous fungi, along with genes for large and small ribosomal RNA subunits, 25 predicted tRNA genes capable of decoding all 20 amino acids, and a single open reading frame potentially coding for a protein of unknown function.The Z. cellare mitochondrial genome had genes encoded on both strands with a single change of direction, different from most other fungi but consistent with the Dothideomycetes. The high synteny among mitochondrial genomes of fungi in the Eurotiomycetes broke down almost completely in the Dothideomycetes.Only a low level of microsynteny was observed among protein-coding and tRNA genes in comparison with Mycosphaerella graminicola (synonym Zymoseptoria tritici), the only other fungus in the order Capnodiales with a sequenced mitochondrial genome, involving the three gene pairs atp8-atp9, nad2-nad3, and nad4L-nad5.However, even this low level of microsynteny did not extend to other fungi in the Dothideomycetes and Eurotiomycetes. Phylogenetic analysis of concatenated protein-coding genes confirmed the relationship between Z. cellare and M. graminicola in the Capnodiales, although conclusions were

  9. Solar Features - Prominences and Filaments

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Prominences and filaments are two manifestations of the same phenomenon. Both prominences and filaments are features formed above the chromosphere by cool dense...

  10. Positrusion Filament Recycling System Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TUI proposes a novel process to produce 3d printer feedstock filament out of scrap ABS on the ISS. Currently the plastic filament materials that most 3d printers use...

  11. Properties of twisted ferromagnetic filaments

    Energy Technology Data Exchange (ETDEWEB)

    Belovs, Mihails; Cebers, Andrejs [University of Latvia, Zellu 8, LV-1002 (Latvia)], E-mail: aceb@tesla.sal.lv

    2009-02-01

    The full set of equations for twisted ferromagnetic filaments is derived. The linear stability analysis of twisted ferromagnetic filament is carried out. Two different types of the buckling instability are found - monotonous and oscillatory. The first in the limit of large twist leads to the shape of filament reminding pearls on the string, the second to spontaneous rotation of the filament, which may constitute the working of chiral microengine.

  12. Solid friction between soft filaments

    CERN Document Server

    Ward, Andrew; Schwenger, Walter; Welch, David; Lau, A W C; Vitelli, Vincenzo; Mahadevan, L; Dogic, Zvonimir

    2015-01-01

    Any macroscopic deformation of a filamentous bundle is necessarily accompanied by local sliding and/or stretching of the constituent filaments. Yet the nature of the sliding friction between two aligned filaments interacting through multiple contacts remains largely unexplored. Here, by directly measuring the sliding forces between two bundled F-actin filaments, we show that these frictional forces are unexpectedly large, scale logarithmically with sliding velocity as in solid-like friction, and exhibit complex dependence on the filaments' overlap length. We also show that a reduction of the frictional force by orders of magnitude, associated with a transition from solid-like friction to Stokes' drag, can be induced by coating F-actin with polymeric brushes. Furthermore, we observe similar transitions in filamentous microtubules and bacterial flagella. Our findings demonstrate how altering a filament's elasticity, structure and interactions can be used to engineer interfilament friction and thus tune the prop...

  13. Simultaneous silencing of multiple genes in the apple scab fungus, Venturia inaequalis, by expression of RNA with chimeric inverted repeats

    NARCIS (Netherlands)

    Fitzgerald, A.; Kan, van J.A.L.; Plummer, K.M.

    2004-01-01

    RNA-mediated gene silencing has been demonstrated in plants, animals, and more recently in filamentous fungi. Here, we report high frequency, RNA-mediated gene silencing in the apple scab fungus, Venturia inaequalis. The green fluorescent protein (GFP) transgene was silenced in a GFP-expressing tran

  14. Anaerobic Digestion: Process

    DEFF Research Database (Denmark)

    Angelidaki, Irini; Batstone, Damien J.

    2011-01-01

    with very little dry matter may also be called a digest. The digest should not be termed compost unless it specifically has been composted in an aerated step. This chapter describes the basic processes of anaerobic digestion. Chapter 9.5 describes the anaerobic treatment technologies, and Chapter 9.......6 addresses the mass balances and environmental aspects of anaerobic digestion....

  15. Filament Identification through Mathematical Morphology

    CERN Document Server

    Koch, Eric W

    2015-01-01

    We present a new algorithm for detecting filamentary structure FilFinder. The algorithm uses the techniques of mathematical morphology for filament identification, presenting a complementary approach to current algorithms which use matched filtering or critical manifolds. Unlike other methods, FilFinder identifies filaments over a wide dynamic range in brightness. We apply the new algorithm to far infrared imaging data of dust emission released by the Herschel Gould Belt Survey team. Our preliminary analysis characterizes both filaments and fainter striations. We find a typical filament width of 0.09 pc across the sample, but the brightness varies from cloud to cloud. Several regions show a bimodal filament brightness distribution, with the bright mode (filaments) being an order of magnitude brighter than the faint mode (striations). Using the Rolling Hough Transform, we characterize the orientations of the striations in the data, finding preferred directions that agree with magnetic field direction where dat...

  16. Chaperonin filaments: The archael cytoskeleton

    Energy Technology Data Exchange (ETDEWEB)

    Trent, J.D.; Kagawa, H.K.; Yaoi, Takuro; Olle, E.; Zaluzec, N.J.

    1997-08-01

    Chaperonins are multi-subunit double-ring complexed composed of 60-kDa proteins that are believed to mediate protein folding in vivo. The chaperonins in the hyperthermophilic archaeon Sulfolobus shibatae are composed of the organism`s two most abundant proteins, which represent 4% of its total protein and have an intracellular concentration of {ge} 3.0 mg/ml. At concentrations of 1.0 mg/ml, purified chaperonin proteins aggregate to form ordered filaments. Filament formation, which requires Mg{sup ++} and nucleotide binding (not hydrolysis), occurs at physiological temperatures under conditions suggesting filaments may exist in vivo. If the estimated 4,600 chaperonins per cell, formed filaments in vivo, they could create a matrix of filaments that would span the diameter of an average S. shibatae cell 100 times. Direct observations of unfixed, minimally treated cells by intermediate voltage electron microscopy (300 kV) revealed an intracellular network of filaments that resembles chaperonin filaments produced in vitro. The hypothesis that the intracellular network contains chaperonins is supported by immunogold analyses. The authors propose that chaperonin activity may be regulated in vivo by filament formation and that chaperonin filaments may serve a cytoskeleton-like function in archaea and perhaps in other prokaryotes.

  17. Functional genomics in the rice blast fungus to unravel the fungal pathogenicity

    Institute of Scientific and Technical Information of China (English)

    Junhyun JEON; Jaehyuk CHOI; Jongsun PARK; Yong-Hwan LEE

    2008-01-01

    A rapidly growing number of successful genome sequencing projects in plant pathogenic fungi greatly increase the demands for tools and methodologies to study fungal pathogenicity at genomic scale. Magnaporthe oryzae is an economically important plant pathogenic fungus whose genome is fully sequenced. Recently we have reported the development and application of functional genomics platform technologies in M. oryzae. This model approach would have many practical ramifications in design and implementation of upcoming functional genomics studies of filamentous fungi aimed at understanding fungal pathogenicity.

  18. CJ-15,183, a new inhibitor of squalene synthase produced by a fungus, Aspergillus aculeatus.

    Science.gov (United States)

    Watanabe, S; Hirai, H; Ishiguro, M; Kambara, T; Kojima, Y; Matsunaga, T; Nishida, H; Suzuki, Y; Sugiura, A; Harwood, H J; Huang, L H; Kojima, N

    2001-11-01

    A new squalene synthase (SSase) inhibitor, CJ-15,183 (I) was isolated from the fermentation broth of a fungus, Aspergillus aculeatus CL38916. The compound potently inhibited rat liver and Candida albicans microsomal SSases and also inhibited the human enzyme. It also showed antifungal activities against filamentous fungi and a yeast. The structure was determined to be an aliphatic tetracarboxylic acid compound consisting of an alkyl gamma-lactone, malic acid and isocitric acid moieties by spectroscopic studies.

  19. Current filamentation model for the Weibel/Filamentation instabilities

    Science.gov (United States)

    Ryu, Chang-Mo; Huynh, Cong Tuan; Kim, Chul Min

    2016-10-01

    A current filamentaion model for a nonrelativistic plasma with e +/e- beam has been presented together with PIC simulations, which can explain the mangetic field enhancement during the Weibel/ Filamentation instabilities. This filament model assumes the Hammer-Rostoker equilibrium. In addition, this model predicts preferential acceleration/deceleration for electron-ion plasmas depending on the injected beam to be e +/e-.

  20. A hydrogenosomal [Fe]-hydrogenase from the anaerobic chytrid Neocallimastix sp. L2

    NARCIS (Netherlands)

    Voncken, Frank G.J.; Boxma, Brigitte; Hoek, Angela H.A.M. van; Akhmanova, Anna S.; Vogels, Godfried D.; Huynen, Martijn; Veenhuis, Marten; Hackstein, Johannes H.P.

    2002-01-01

    The presence of a [Fe]-hydrogenase in the hydrogenosomes of the anaerobic chytridiomycete fungus Neocallimastix sp. L2 has been demonstrated by immunocytochemistry, subcellular fractionation, Western-blotting and measurements of hydrogenase activity in the presence of various concentrations of carbo

  1. A hydrogenosomal [Fe]-hydrogenase from the anaerobic chytrid Neocallimastix sp L2

    NARCIS (Netherlands)

    Voncken, Frank G.J.; Boxma, Brigitte; Hoek, Angela H.A.M. van; Akhmanova, Anna S.; Vogels, Godfried D.; Huynen, Martijn; Veenhuis, Marten; Hackstein, Johannes H.P.

    2002-01-01

    The presence of a [Fe]-hydrogenase in the hydrogenosomes of the anaerobic chytridiomycete fungus Neocallimastix sp. L2 has been demonstrated by immunocytochemistry, subcellular fractionation, Western-blotting, and measurements of hydrogenase activity in the presence of various concentrations of carb

  2. Metabolomics protocols for filamentous fungi.

    Science.gov (United States)

    Gummer, Joel P A; Krill, Christian; Du Fall, Lauren; Waters, Ormonde D C; Trengove, Robert D; Oliver, Richard P; Solomon, Peter S

    2012-01-01

    Proteomics and transcriptomics are established functional genomics tools commonly used to study filamentous fungi. Metabolomics has recently emerged as another option to complement existing techniques and provide detailed information on metabolic regulation and secondary metabolism. Here, we describe broad generic protocols that can be used to undertake metabolomics studies in filamentous fungi.

  3. Purification and characterization of a novel phospholipid transfer protein from filamentous fungi.

    Science.gov (United States)

    Grondin, P; Vergnolle, C; Chavant, L; Kader, J C

    1990-01-01

    1. We have isolated from mycelia of Mucor mucedo, a filamentous fungus, a phospholipid transfer protein. 2. The purification steps were gel filtration, hydroxyapatite chromatography, blue affinity column and fast protein liquid chromatography on anion exchanger. 3. A purified protein was obtained with a molecular mass of 24 kDa and a pI of 5.05 and its N-terminal sequence was established. 4. This protein transfers phosphatidylinositol, as well as phosphatidylcholine and phosphatidylethanolamine.

  4. Resonantly enhanced filamentation in gases

    CERN Document Server

    Doussot, J; Billard, F; Béjot, P; Faucher, O

    2016-01-01

    In this Letter, a low-loss Kerr-driven optical filament in Krypton gas is experimentally reported in the ultraviolet. The experimental findings are supported by ab initio quantum calculations describing the atomic optical response. Higher-order Kerr effect induced by three-photon resonant transitions is identified as the underlying physical mechanism responsible for the intensity stabilization during the filamentation process, while ionization plays only a minor role. This result goes beyond the commonly-admitted paradigm of filamentation, in which ionization is a necessary condition of the filament intensity clamping. At resonance, it is also experimentally demonstrated that the filament length is greatly extended because of a strong decrease of the optical losses.

  5. Perturbation growth in accreting filaments

    CERN Document Server

    Clarke, Seamus D; Hubber, David A

    2016-01-01

    We use smoothed particle hydrodynamic simulations to investigate the growth of perturbations in infinitely long, initially sub-critical but accreting filaments. The growth of these perturbations leads to filament fragmentation and the formation of cores. Most previous work on this subject has been confined to the growth and fragmentation of equilibrium filaments and has found that there exists a preferential fragmentation length scale which is roughly 4 times the filament's diameter. Our results show a more complicated dispersion relation with a series of peaks linking perturbation wavelength and growth rate. These are due to gravo-acoustic oscillations along the longitudinal axis during the sub-critical phase of growth. The positions of the peaks in growth rate have a strong dependence on both the mass accretion rate onto the filament and the temperature of the gas. When seeded with a multi-wavelength density power spectrum there exists a clear preferred core separation equal to the largest peak in the dispe...

  6. Perturbation growth in accreting filaments

    Science.gov (United States)

    Clarke, S. D.; Whitworth, A. P.; Hubber, D. A.

    2016-05-01

    We use smoothed particle hydrodynamic simulations to investigate the growth of perturbations in infinitely long filaments as they form and grow by accretion. The growth of these perturbations leads to filament fragmentation and the formation of cores. Most previous work on this subject has been confined to the growth and fragmentation of equilibrium filaments and has found that there exists a preferential fragmentation length-scale which is roughly four times the filament's diameter. Our results show a more complicated dispersion relation with a series of peaks linking perturbation wavelength and growth rate. These are due to gravo-acoustic oscillations along the longitudinal axis during the sub-critical phase of growth. The positions of the peaks in growth rate have a strong dependence on both the mass accretion rate onto the filament and the temperature of the gas. When seeded with a multiwavelength density power spectrum, there exists a clear preferred core separation equal to the largest peak in the dispersion relation. Our results allow one to estimate a minimum age for a filament which is breaking up into regularly spaced fragments, as well as an average accretion rate. We apply the model to observations of filaments in Taurus by Tafalla & Hacar and find accretion rates consistent with those estimated by Palmeirim et al.

  7. Activity Cycle of Solar Filaments

    Indian Academy of Sciences (India)

    K. J. Li; Q. X. Li; P. X. Gao; J. Mu; H. D. Chen; T. W. Su

    2007-06-01

    Long-term variation in the distribution of the solar filaments observed at the Observatorie de Paris, Section de Meudon from March 1919 to December 1989 is presented to compare with sunspot cycle and to study the periodicity in the filament activity, namely the periods of the coronal activity with the Morlet wavelet used. It is inferred that the activity cycle of solar filaments should have the same cycle length as sunspot cycle, but the cycle behavior of solar filaments is globally similar in profile with, but different in detail from, that of sunspot cycles. The amplitude of solar magnetic activity should not keep in phase with the complexity of solar magnetic activity. The possible periods in the filament activity are about 10.44 and 19.20 years. The wavelet local power spectrum of the period 10.44 years is statistically significant during the whole consideration time. The wavelet local power spectrum of the period 19.20 years is under the 95% confidence spectrum during the whole consideration time, but over the mean red-noise spectrum of = 0.72 before approximate Carrington rotation number 1500, and after that the filament activity does not statistically show the period. Wavelet reconstruction indicates that the early data of the filament archive (in and before cycle 16) are more noiseful than the later (in and after cycle 17).

  8. Comparative Biomechanics of Thick Filaments and Thin Filaments with Functional Consequences for Muscle Contraction

    Directory of Open Access Journals (Sweden)

    Mark S. Miller

    2010-01-01

    Full Text Available The scaffold of striated muscle is predominantly comprised of myosin and actin polymers known as thick filaments and thin filaments, respectively. The roles these filaments play in muscle contraction are well known, but the extent to which variations in filament mechanical properties influence muscle function is not fully understood. Here we review information on the material properties of thick filaments, thin filaments, and their primary constituents; we also discuss ways in which mechanical properties of filaments impact muscle performance.

  9. Noncatalytic Docking Domains of Cellulosomes of Anaerobic Fungi

    Science.gov (United States)

    Steenbakkers, Peter J. M.; Li, Xin-Liang; Ximenes, Eduardo A.; Arts, Jorik G.; Chen, Huizhong; Ljungdahl, Lars G.; Op den Camp, Huub J. M.

    2001-01-01

    A method is presented for the specific isolation of genes encoding cellulosome components from anaerobic fungi. The catalytic components of the cellulosome of anaerobic fungi typically contain, besides the catalytic domain, mostly two copies of a 40-amino-acid cysteine-rich, noncatalytic docking domain (NCDD) interspaced by short linkers. Degenerate primers were designed to anneal to the highly conserved region within the NCDDs of the monocentric fungus Piromyces sp. strain E2 and the polycentric fungus Orpinomyces sp. strain PC-2. Through PCR using cDNA from Orpinomyces sp. and genomic DNA from Piromyces sp. as templates, respectively, 9 and 19 PCR products were isolated encoding novel NCDD linker sequences. Screening of an Orpinomyces sp. cDNA library with four of these PCR products resulted in the isolation of new genes encoding cellulosome components. An alignment of the partial NCDD sequence information obtained and an alignment of database-accessible NCDD sequences, focusing on the number and position of cysteine residues, indicated the presence of three structural subfamilies within fungal NCDDs. Furthermore, evidence is presented that the NCDDs in CelC from the polycentric fungus Orpinomyces sp. strain PC-2 specifically recognize four proteins in a cellulosome preparation, indicating the presence of multiple scaffoldins. PMID:11514516

  10. Collisions of Vortex Filament Pairs

    Science.gov (United States)

    Banica, Valeria; Faou, Erwan; Miot, Evelyne

    2014-12-01

    We consider the problem of collisions of vortex filaments for a model introduced by Klein et al. (J Fluid Mech 288:201-248, 1995) and Zakharov (Sov Phys Usp 31(7):672-674, 1988, Lect. Notes Phys 536:369-385, 1999) to describe the interaction of almost parallel vortex filaments in three-dimensional fluids. Since the results of Crow (AIAA J 8:2172-2179, 1970) examples of collisions are searched as perturbations of antiparallel translating pairs of filaments, with initial perturbations related to the unstable mode of the linearized problem; most results are numerical calculations. In this article, we first consider a related model for the evolution of pairs of filaments, and we display another type of initial perturbation leading to collision in finite time. Moreover, we give numerical evidence that it also leads to collision through the initial model. We finally study the self-similar solutions of the model.

  11. Filament Identification through Mathematical Morphology

    OpenAIRE

    Koch, Eric W.; Rosolowsky, Erik W.

    2015-01-01

    We present a new algorithm for detecting filamentary structure FilFinder. The algorithm uses the techniques of mathematical morphology for filament identification, presenting a complementary approach to current algorithms which use matched filtering or critical manifolds. Unlike other methods, FilFinder identifies filaments over a wide dynamic range in brightness. We apply the new algorithm to far infrared imaging data of dust emission released by the Herschel Gould Belt Survey team. Our prel...

  12. The genome of the white-rot fungus Pycnoporus cinnabarinus : a basidiomycete model with a versatile arsenal for lignocellulosic biomass breakdown

    NARCIS (Netherlands)

    Levasseur, Anthony; Lomascolo, Anne; Chabrol, Olivier; Ruiz-Dueñas, Francisco J; Boukhris-Uzan, Eva; Piumi, François; Kües, Ursula; Ram, Arthur F J; Murat, Claude; Haon, Mireille; Benoit, Isabelle; Arfi, Yonathan; Chevret, Didier; Drula, Elodie; Kwon, Min Jin; Gouret, Philippe; Lesage-Meessen, Laurence; Lombard, Vincent; Mariette, Jérôme; Noirot, Céline; Park, Joohae; Patyshakuliyeva, Aleksandrina; Sigoillot, Jean Claude; Wiebenga, Ad; Wösten, Han A B; Martin, Francis; Coutinho, Pedro M; de Vries, Ronald P; Martínez, Angel T; Klopp, Christophe; Pontarotti, Pierre; Henrissat, Bernard; Record, Eric; Wosten, Han

    2014-01-01

    BACKGROUND: Saprophytic filamentous fungi are ubiquitous micro-organisms that play an essential role in photosynthetic carbon recycling. The wood-decayer Pycnoporus cinnabarinus is a model fungus for the study of plant cell wall decomposition and is used for a number of applications in green and whi

  13. The genome of the white-rot fungus Pycnoporus cinnabarinus: a basidiomycete model with a versatile arsenal for lignocellulosic biomass breakdown

    NARCIS (Netherlands)

    Levasseur, Anthony; Lomascolo, Anne; Chabrol, Olivier; Ruiz-Dueñas, Francisco J; Boukhris-Uzan, Eva; Piumi, François; Kües, Ursula; Ram, Arthur F J; Murat, Claude; Haon, Mireille; Benoit, Isabelle; Arfi, Yonathan; Chevret, Didier; Drula, Elodie; Kwon, Min Jin; Gouret, Philippe; Lesage-Meessen, Laurence; Lombard, Vincent; Mariette, Jérôme; Noirot, Céline; Park, Joohae; Patyshakuliyeva, Aleksandrina; Sigoillot, Jean Claude; Wiebenga, A.; Wösten, Han A B; Martin, Francis; Coutinho, Pedro M; de Vries, Ronald P; Martínez, Angel T; Klopp, Christophe; Pontarotti, Pierre; Henrissat, Bernard; Record, Eric; van den Brink, J.

    2014-01-01

    BACKGROUND: Saprophytic filamentous fungi are ubiquitous micro-organisms that play an essential role in photosynthetic carbon recycling. The wood-decayer Pycnoporus cinnabarinus is a model fungus for the study of plant cell wall decomposition and is used for a number of applications in green and whi

  14. Anaerobic Digestion and its Applications

    Science.gov (United States)

    Anaerobic digestion is a natural biological process. The initials "AD" may refer to the process of anaerobic digestion, or the built systems of anaerobic digesters. While there are many kinds of digesters, the biology is basically the same for all. Anaerobic digesters are built...

  15. Anaerobic Digestion Foaming Causes

    OpenAIRE

    Ganidi, Nafsika

    2008-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water utilities due to significant impacts on process efficiency and operational costs. Several foaming causes have been suggested over the past few years by researchers. However, the supporting experimental information is limited and in some cases site specific. The present report aimed to provide a better understanding of the anaerobic di...

  16. Multiple origins of hydrogenosomes : functional and phylogenetic evidence from the ADP/ATP carrier of the anaerobic chytrid Neocallimastix sp.

    NARCIS (Netherlands)

    Voncken, F; Boxma, B; Tjaden, J; Akhmanova, A; Huynen, M; Tielens, AGM; Haferkamp, [No Value; Neuhaus, HE; Vogels, G; Veenhuis, M; Hackstein, JHP; Tielens, Aloysius G.M.; Haferkamp, Ilka; Hackstein, Johannes H.P.

    2002-01-01

    A mitochondrial-type ADP/ATP carrier (AAC) has been identified in the hydrogenosomes of the anaerobic chytridiomycete fungus Neocallimastix sp. L2. Biochemical and immunocytochemical studies revealed that this ADP/ATP carrier is an integral component of hydrogenosomal membranes. Expression of the co

  17. Boolean gates on actin filaments

    Science.gov (United States)

    Siccardi, Stefano; Tuszynski, Jack A.; Adamatzky, Andrew

    2016-01-01

    Actin is a globular protein which forms long polar filaments in the eukaryotic cytoskeleton. Actin networks play a key role in cell mechanics and cell motility. They have also been implicated in information transmission and processing, memory and learning in neuronal cells. The actin filaments have been shown to support propagation of voltage pulses. Here we apply a coupled nonlinear transmission line model of actin filaments to study interactions between voltage pulses. To represent digital information we assign a logical TRUTH value to the presence of a voltage pulse in a given location of the actin filament, and FALSE to the pulse's absence, so that information flows along the filament with pulse transmission. When two pulses, representing Boolean values of input variables, interact, then they can facilitate or inhibit further propagation of each other. We explore this phenomenon to construct Boolean logical gates and a one-bit half-adder with interacting voltage pulses. We discuss implications of these findings on cellular process and technological applications.

  18. Galaxy pairs align with galactic filaments

    CERN Document Server

    Tempel, Elmo

    2015-01-01

    Context. Gravitational collapse theory and numerical simulations suggest that the velocity field within large-scale galaxy filaments is dominated by motions along the filaments. Aims. Our aim is to check whether observational data reveal any preferred orientation of galaxy pairs with respect to the underlying filaments as a result of the expectedly anisotropic velocity field. Methods. We use galaxy pairs and galaxy filaments identified from the Sloan Digital Sky Survey data. For filament extraction, we use the Bisous model that is based the marked point process technique. During the filament detection, we use the centre point of each pair instead of the positions of galaxies to avoid a built-in influence of pair orientation on the filament construction. For pairs lying within filaments (3012 cases), we calculate the angle between the line connecting galaxies of each pair and their host filament. To avoid redshift-space distortions, the angle is measured in the plain of the sky. Results. The alignment analysis...

  19. Temperature Controlled Filamentation in Argon Gas

    Institute of Scientific and Technical Information of China (English)

    CAO Shi-Ying; KONG Wei-Peng; SONG Zhen-Ming; QIN Yu; LI Ru-Xin; WANG Qing-Yue; ZHANG Zhi-Gang

    2008-01-01

    Temperature controlled filamentation is experimentally demonstrated in a temperature gradient gas-filled tube.The proper position of the tube is heated by a furnace and two ends of the tube are cooled by air. The experimental results show that multiple filaments are shrunken into a single fila.ment or no filament only by increasing the temperature at the beginning of the filament. This technique offers another degree of freedom of controlling the filamentation and opens a new way for intense monocycle pulse generation through gradient temperature in a noble gas.

  20. Intermediate Filaments in Caenorhabditis elegans.

    Science.gov (United States)

    Zuela, Noam; Gruenbaum, Yosef

    2016-01-01

    More than 70 different genes in humans and 12 different genes in Caenorhabditis elegans encode the superfamily of intermediate filament (IF) proteins. In C. elegans, similar to humans, these proteins are expressed in a cell- and tissue-specific manner, can assemble into heteropolymers and into 5-10nm wide filaments that account for the principal structural elements at the nuclear periphery, nucleoplasm, and cytoplasm. At least 5 of the 11 cytoplasmic IFs, as well as the nuclear IF, lamin, are essential. In this chapter, we will include a short review of our current knowledge of both cytoplasmic and nuclear IFs in C. elegans and will describe techniques used for their analyses.

  1. Methods for transforming and expression screening of filamentous fungal cells with a DNA library

    Energy Technology Data Exchange (ETDEWEB)

    Teter, Sarah; Lamsa, Michael; Cherry, Joel; Ward, Connie

    2015-06-02

    The present invention relates to methods for expression screening of filamentous fungal transformants, comprising: (a) isolating single colony transformants of a DNA library introduced into E. coli; (b) preparing DNA from each of the single colony E. coli transformants; (c) introducing a sample of each of the DNA preparations of step (b) into separate suspensions of protoplasts of a filamentous fungus to obtain transformants thereof, wherein each transformant contains one or more copies of an individual polynucleotide from the DNA library; (d) growing the individual filamentous fungal transformants of step (c) on selective growth medium, thereby permitting growth of the filamentous fungal transformants, while suppressing growth of untransformed filamentous fungi; and (e) measuring activity or a property of each polypeptide encoded by the individual polynucleotides. The present invention also relates to isolated polynucleotides encoding polypeptides of interest obtained by such methods, to nucleic acid constructs, expression vectors, and recombinant host cells comprising the isolated polynucleotides, and to methods of producing the polypeptides encoded by the isolated polynucleotides.

  2. Fungus symbionts colonizing the galleries of the ambrosia beetle Platypus quercivorus.

    Science.gov (United States)

    Endoh, Rikiya; Suzuki, Motofumi; Okada, Gen; Takeuchi, Yuko; Futai, Kazuyoshi

    2011-07-01

    Isolations were made to determine the fungal symbionts colonizing Platypus quercivorus beetle galleries of dead or dying Quercus laurifolia, Castanopsis cuspidata, Quercus serrata, Quercus crispula, and Quercus robur. For these studies, logs from oak wilt-killed trees were collected from Kyoto Prefecture, Japan. Fungi were isolated from the: (1) entrances of beetle galleries, (2) vertical galleries, (3) lateral galleries, and (4) the larval cradle of P. quercivorus in each host tree. Among the fungus colonies which appeared on YM agar plates, 1,219 were isolated as the representative isolates for fungus species inhabiting in the galleries based on their cultural characteristics. The validity of the visual classification of the fungus colonies was checked and if necessary properly corrected using microsatellite-primed PCR fingerprints. The nucleotide sequence of the D1/D2 region of the large subunit nuclear rRNA gene detected 38 fungus species (104 strains) of which three species, i.e., Candida sp. 3, Candida kashinagacola (both yeasts), and the filamentous fungus Raffaelea quercivora were isolated from all the tree species. The two yeasts were most prevalent in the interior of galleries, regardless of host tree species, suggesting their close association with the beetle. A culture-independent method, terminal restriction fragment length polymorphism (T-RFLP) analysis was also used to characterize the fungus flora of beetle galleries. T-RFLP patterns showed that yeast species belonging to the genus Ambrosiozyma frequently occurred on the gallery walls along with the two Candida species. Ours is the first report showing the specific fungi inhabiting the galleries of a platypodid ambrosia beetle.

  3. Anaerobic Biodegradation of Detergent Surfactants

    Directory of Open Access Journals (Sweden)

    Erich Jelen

    2009-03-01

    Full Text Available Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have strictly anaerobic conditions. This review gives an overview on anaerobic biodegradation processes, the methods for testing anaerobic biodegradability, and the anaerobic biodegradability of different detergent surfactant types (anionic, nonionic, cationic, amphoteric surfactants.

  4. Picosecond laser filamentation in air

    Science.gov (United States)

    2016-09-02

    LeibnizUniversityHannover,Welfengarten 1, D-30167Hannover, Germany 3 CEA-DAM,DIF, F-91297Arpajon, France 4 Univ.Bordeaux—CNRS—CEA,Centre Lasers ...optics.arizona.edu Keywords: laser filamentation, picosecond laser pulses, nonlinear propagation, optical ionization Abstract The propagation of intense

  5. Transient filament stretching rheometer II

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

    1997-01-01

    The Lagrangian sspecification is used to simulate the transient stretching filament rheometer. Simulations are performed for dilute PIB-solutions modeled as a four mode Oldroyd-B fluid and a semidilute PIB-solution modeled as a non-linear single integral equation. The simulations are compared...

  6. Merger of Long Vortex Filaments

    CERN Document Server

    Khandekar, Akshay

    2012-01-01

    This fluid dynamics video demonstrates the merger of long vortex filaments is shown experimentally. Two counter-rotating vortices are generated using in a tank with very high aspect ratio. PIV demonstrates the merger of the vortices within a single orbit.

  7. Filament Winding. A Unified Approach

    NARCIS (Netherlands)

    Koussios, S.

    2004-01-01

    In this dissertation we have presented an overview and comprehensive treatment of several facets of the filament winding process. With the concepts of differential geometry and the theory of thin anisotropic shells of revolution, a parametric shape generator has been formulated for the design proced

  8. Towards filament free semiconductor lasers

    DEFF Research Database (Denmark)

    McInerney, John; O'Brien, Peter; Skovgaard, Peter M. W.

    2000-01-01

    We outline physical models and simulations for suppression of self-focusing and filamentation in large aperture semiconductor lasers. The principal technical objective is to generate multi-watt CW or quasi-CW outputs with nearly diffraction limited beams, suitable for long distance free space...

  9. Capillary thinning of polymeric filaments

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Szabo, Peter

    1999-01-01

    The capillary thinning of filaments of a Newtonian polybutene fluid and a viscoelastic polyisobutylene solution are analyzed experimentally and by means of numerical simulation. The experimental procedure is as follows. Initially, a liquid sample is placed between two cylindrical plates. Then, th...... and quantified. (C) 1999 The Society of Rheology. [S0148-6055(99)00103-0]....

  10. Role of Intermediate Filaments in Vesicular Traffic

    Directory of Open Access Journals (Sweden)

    Azzurra Margiotta

    2016-04-01

    Full Text Available Intermediate filaments are an important component of the cellular cytoskeleton. The first established role attributed to intermediate filaments was the mechanical support to cells. However, it is now clear that intermediate filaments have many different roles affecting a variety of other biological functions, such as the organization of microtubules and microfilaments, the regulation of nuclear structure and activity, the control of cell cycle and the regulation of signal transduction pathways. Furthermore, a number of intermediate filament proteins have been involved in the acquisition of tumorigenic properties. Over the last years, a strong involvement of intermediate filament proteins in the regulation of several aspects of intracellular trafficking has strongly emerged. Here, we review the functions of intermediate filaments proteins focusing mainly on the recent knowledge gained from the discovery that intermediate filaments associate with key proteins of the vesicular membrane transport machinery. In particular, we analyze the current understanding of the contribution of intermediate filaments to the endocytic pathway.

  11. Epigenetic genome mining of an endophytic fungus leads to the pleiotropic biosynthesis of natural products.

    Science.gov (United States)

    Mao, Xu-Ming; Xu, Wei; Li, Dehai; Yin, Wen-Bing; Chooi, Yit-Heng; Li, Yong-Quan; Tang, Yi; Hu, Youcai

    2015-06-22

    The small-molecule biosynthetic potential of most filamentous fungi has remained largely unexplored and represents an attractive source for the discovery of new compounds. Genome sequencing of Calcarisporium arbuscula, a mushroom-endophytic fungus, revealed 68 core genes that are involved in natural product biosynthesis. This is in sharp contrast to the predominant production of the ATPase inhibitors aurovertin B and D in the wild-type fungus. Inactivation of a histone H3 deacetylase led to pleiotropic activation and overexpression of more than 75 % of the biosynthetic genes. Sampling of the overproduced compounds led to the isolation of ten compounds of which four contained new structures, including the cyclic peptides arbumycin and arbumelin, the diterpenoid arbuscullic acid A, and the meroterpenoid arbuscullic acid B. Such epigenetic modifications therefore provide a rapid and global approach to mine the chemical diversity of endophytic fungi.

  12. Analysis of a filament stretching rheometer

    DEFF Research Database (Denmark)

    Kolte, Mette Irene; Rasmussen, Henrik K.; Hassager, Ole

    1996-01-01

    A finite element analysis of the stretching filament rheometer of Tirtaadmadja and Sridhar (1993) is presenetd. Simulations of the stretching of a filament of the polymet test solution, fluid A, between two plates are shown.......A finite element analysis of the stretching filament rheometer of Tirtaadmadja and Sridhar (1993) is presenetd. Simulations of the stretching of a filament of the polymet test solution, fluid A, between two plates are shown....

  13. Preparation and Characterization of Carbon Filaments

    Science.gov (United States)

    1991-04-01

    catalysts gave straight filaments, while the use of nickel and other catalysts resulted in a variety of vermicular forms of filaments. Ferrocene, (C5H5)2Fe...vapor deposition of carbon filaments is presented along with a theory for the vermicular growth of filaments on quartz substrates. I U I I I I I I...one hour. The experimental details of the matrix and results are discussed, also theories for the role of hydrogen and the vermicular growth of

  14. Large-scale Motion of Solar Filaments

    Indian Academy of Sciences (India)

    Pavel Ambrož; Alfred Schroll

    2000-09-01

    Precise measurements of heliographic position of solar filaments were used for determination of the proper motion of solar filaments on the time-scale of days. The filaments have a tendency to make a shaking or waving of the external structure and to make a general movement of whole filament body, coinciding with the transport of the magnetic flux in the photosphere. The velocity scatter of individual measured points is about one order higher than the accuracy of measurements.

  15. Anaerobic bacteria in otitis media.

    Science.gov (United States)

    Fulghum, R S; Daniel, H J; Yarborough, J G

    1977-01-01

    Anaerobic bacteria, Peptostrepotococcus intermedius and Propionibacterium acnes, were found in mixed culture specimens from four to ten tested cases of chronic secretory otitis media. These anaerobic bacteria were in a mixed infection flora with aerobic bacteria most often Staphylococcus epidermidis and Cornybacterium sp. which do not fit any established species. The findings of anaerobic bacteria in otitis media is consistent with the sporadic report of the involvement of anaerobic bacteria in otitis media in the literature since 1898.

  16. Remote electrical arc suppression by laser filamentation

    CERN Document Server

    Schubert, Elise; Kasparian, Jérôme; Wolf, Jean-Pierre

    2015-01-01

    We investigate the interaction of narrow plasma channels formed in the filamentation of ultrashort laser pulses, with a DC high voltage. The laser filaments prevent electrical arcs by triggering corona that neutralize the high-voltage electrodes. This phenomenon, due to the electric field modulation and free electron release around the filament, opens new prospects to lightning and over-voltage mitigation.

  17. Tailor-made TALEN system for highly efficient targeted gene replacement in the rice blast fungus.

    Science.gov (United States)

    Arazoe, Takayuki; Ogawa, Tetsuo; Miyoshi, Kennosuke; Yamato, Tohru; Ohsato, Shuichi; Sakuma, Tetsushi; Yamamoto, Takashi; Arie, Tsutomu; Kuwata, Shigeru

    2015-07-01

    Genetic manipulation is key to unraveling gene functions and creating genetically modified strains of microbial organisms. Recently, engineered nucleases that can generate DNA double-strand breaks (DSBs) at a specific site in the desired locus within genome are utilized in a rapidly developing genome editing technology via DSBs repair. However, the use of engineered nucleases in filamentous fungi has not been validated. In this study, we demonstrated that tailor-made transcriptional activator-like effector nucleases (TALENs) system, Platinum-Fungal TALENs (PtFg TALENs), could improve the efficiency of homologous recombination-mediated targeted gene replacement by up to 100% in the rice blast fungus Pyricularia oryzae. This high-efficiency PtFg TALEN has great potential for basic and applied biological applications in filamentous fungi.

  18. The septin AspB in Aspergillus nidulans forms bars and filaments and plays roles in growth emergence and conidiation.

    Science.gov (United States)

    Hernández-Rodríguez, Yainitza; Hastings, Susan; Momany, Michelle

    2012-03-01

    In yeast, septins form rings at the mother-bud neck and function as diffusion barriers. In animals, septins form filaments that can colocalize with other cytoskeletal elements. In the filamentous fungus Aspergillus nidulans there are five septin genes, aspA (an ortholog of Saccharomyces cerevisiae CDC11), aspB (an ortholog of S. cerevisiae CDC3), aspC (an ortholog of S. cerevisiae CDC12), aspD (an ortholog of S. cerevisiae CDC10), and aspE (found only in filamentous fungi). The aspB gene was previously reported to be the most highly expressed Aspergillus nidulans septin and to be essential. Using improved gene targeting techniques, we found that deletion of aspB is not lethal but results in delayed septation, increased emergence of germ tubes and branches, and greatly reduced conidiation. We also found that AspB-green fluorescent protein (GFP) localizes as rings and collars at septa, branches, and emerging layers of the conidiophore and as bars and filaments in conidia and hyphae. Bars are found in dormant and isotropically expanding conidia and in subapical nongrowing regions of hyphae and display fast movements. Filaments form as the germ tube emerges, localize to hyphal and branch tips, and display slower movements. All visible AspB-GFP structures are retained in ΔaspD and lost in ΔaspA and ΔaspC strains. Interestingly, in the ΔaspE mutant, AspB-GFP rings, bars, and filaments are visible in early growth, but AspB-GFP rods and filaments disappear after septum formation. AspE orthologs are only found in filamentous fungi, suggesting that this class of septins might be required for stability of septin bars and filaments in highly polar cells.

  19. The anaerobic digestion process

    Energy Technology Data Exchange (ETDEWEB)

    Rivard, C.J. [National Renewable Energy Lab., Golden, CO (United States); Boone, D.R. [Oregon Graduate Inst., Portland, OR (United States)

    1996-01-01

    The microbial process of converting organic matter into methane and carbon dioxide is so complex that anaerobic digesters have long been treated as {open_quotes}black boxes.{close_quotes} Research into this process during the past few decades has gradually unraveled this complexity, but many questions remain. The major biochemical reactions for forming methane by methanogens are largely understood, and evolutionary studies indicate that these microbes are as different from bacteria as they are from plants and animals. In anaerobic digesters, methanogens are at the terminus of a metabolic web, in which the reactions of myriads of other microbes produce a very limited range of compounds - mainly acetate, hydrogen, and formate - on which the methanogens grow and from which they form methane. {open_quotes}Interspecies hydrogen-transfer{close_quotes} and {open_quotes}interspecies formate-transfer{close_quotes} are major mechanisms by which methanogens obtain their substrates and by which volatile fatty acids are degraded. Present understanding of these reactions and other complex interactions among the bacteria involved in anaerobic digestion is only now to the point where anaerobic digesters need no longer be treated as black boxes.

  20. Anaerobic digestion without biogas?

    NARCIS (Netherlands)

    Kleerebezem, R.; Joosse, B.; Rozendaal, R.; Van Loosdrecht, M.C.M.

    2015-01-01

    Anaerobic digestion for the production of methane containing biogas is the classic example of a resource recovery process that combines stabilization of particulate organic matter or wastewater treatment with the production of a valuable end-product. Attractive features of the process include the pr

  1. Anaerobic treatment of wastewater. Application for food industry; Depuracion anaerobia del aguas residuales. Se aplicacion en la industria alimentaria

    Energy Technology Data Exchange (ETDEWEB)

    Carceller Rosa, J. M.

    2005-07-01

    Activated sludge aerobic reactors is a wide spread system in waste water treatment plants. Excessive proliferations of filamentous microorganisms give rise to bulking and foaming problems. Wastewater from food and drink industries as well as paper mill and related industries has severe risk of bulking episodes. Incorporation of anaerobic pre-treatment previous to existing aerobic treatment previous to existing aerobic treatment avoids bulking problems. Anaerobic systems are therefore indicated in waste waters with high concentrations of ready biodegradable organic substrates, such us waste waters from breweries, distilleries, soft drinks, paper mill industries, vegetable processing industries, etc. Basic principles of anaerobic wastewater treatment are exposed in this paper, with special reference to the most wide spread anaerobic systems: UASB, EGSB e IC reactors. Operational parameters of anaerobic and aerobic systems are compared, as well as investment and management costs, including biogas recovery. (Author) 7 refs.

  2. Picosecond laser filamentation in air

    CERN Document Server

    Schmitt-Sody, Andreas; Bergé, L; Skupin, S; Polynkin, Pavel

    2016-01-01

    The propagation of intense picosecond laser pulses in air in the presence of strong nonlinear self-action effects and air ionization is investigated experimentally and numerically. The model used for numerical analysis is based on the nonlinear propagator for the optical field coupled with the rate equations for the production of various ionic species and plasma temperature. Our results show that the phenomenon of plasma-driven intensity clamping, which is paramount in femtosecond laser filamentation, holds for picosecond pulses. Furthermore, the temporal pulse distortions are limited and the pulse fluence is also clamped. The resulting unique feature of the picosecond filamentation regime is the production of a broad, fully ionized air channel, continuous both longitudinally and transversely, which may be instrumental for numerous applications.

  3. Picosecond laser filamentation in air

    Science.gov (United States)

    Schmitt-Sody, Andreas; Kurz, Heiko G.; Bergé, Luc; Skupin, Stefan; Polynkin, Pavel

    2016-09-01

    The propagation of intense picosecond laser pulses in air in the presence of strong nonlinear self-action effects and air ionization is investigated experimentally and numerically. The model used for numerical analysis is based on the nonlinear propagator for the optical field coupled to the rate equations for the production of various ionic species and plasma temperature. Our results show that the phenomenon of plasma-driven intensity clamping, which has been paramount in femtosecond laser filamentation, holds for picosecond pulses. Furthermore, the temporal pulse distortions in the picosecond regime are limited and the pulse fluence is also clamped. In focused propagation geometry, a unique feature of picosecond filamentation is the production of a broad, fully ionized air channel, continuous both longitudinally and transversely, which may be instrumental for many applications including laser-guided electrical breakdown of air, channeling microwave beams and air lasing.

  4. Dynamics of 3D isolated thermal filaments

    CERN Document Server

    Walkden, N R; Militello, F; Omotani, J T

    2016-01-01

    Simulations have been carried out to establish how electron thermal physics, introduced in the form of a dynamic electron temperature, affects isolated filament motion and dynamics in 3D. It is found that thermal effects impact filament motion in two major ways when the filament has a significant temperature perturbation compared to its density perturbation: They lead to a strong increase in filament propagation in the bi-normal direction and a significant decrease in net radial propagation. Both effects arise from the temperature dependence of the sheath current which leads to a non-uniform floating potential, with the latter effect supplemented by faster pressure loss. The reduction in radial velocity can only occur when the filament cross-section loses angular symmetry. The behaviour is observed across different filament sizes and suggests that filaments with much larger temperature perturbations than density perturbations are more strongly confined to the near SOL region.

  5. Microwave processing of ceramic oxide filaments

    Energy Technology Data Exchange (ETDEWEB)

    Vogt, G.J.; Katz, J.D. [Los Alamos National Laboratory, NM (United States)

    1995-05-01

    The objective of the microwave filament processing project is to develop microwave techniques at 2.45 GHZ to manufacture continuous ceramic oxide filaments. Microwave processing uses the volumetric absorption of microwave power in oxide filament tows to drive off process solvents, to burn out organic binders, and to sinter the dried fibers to produce flexible, high-strength ceramic filaments. The technical goal is to advance filament processing technology by microwave heating more rapidly with less energy and at a lower cost than conventional processing, but with the same quality as conventional processing. The manufacturing goal is to collaborate with the 3M Company, a US manufacturer of ceramic oxide filaments, to evaluate the technology using a prototype filament system and to transfer the microwave technology to the 3M Company.

  6. Dynamics of 3D isolated thermal filaments

    Science.gov (United States)

    Walkden, N. R.; Easy, L.; Militello, F.; Omotani, J. T.

    2016-11-01

    Simulations have been carried out to establish how electron thermal physics, introduced in the form of a dynamic electron temperature, affects isolated filament motion and dynamics in 3D. It is found that thermal effects impact filament motion in two major ways when the pressure perturbation within the filament is supported primarily through a temperature increase as opposed to density: they lead to a strong increase in filament propagation in the bi-normal direction and a significant decrease in net radial propagation. Both effects arise from the temperature dependence of the sheath current which leads to a non-uniform floating potential, with the latter effect supplemented by faster pressure loss. The reduction in radial velocity can only occur when the filament cross-section loses angular symmetry. The behaviour is observed across different filament sizes and suggests that filaments with much larger temperature perturbations than density perturbations are more strongly confined to the near SOL region.

  7. Programmed cell cycle arrest is required for infection of corn plants by the fungus Ustilago maydis.

    Science.gov (United States)

    Castanheira, Sónia; Mielnichuk, Natalia; Pérez-Martín, José

    2014-12-01

    Ustilago maydis is a plant pathogen that requires a specific structure called infective filament to penetrate the plant tissue. Although able to grow, this filament is cell cycle arrested on the plant surface. This cell cycle arrest is released once the filament penetrates the plant tissue. The reasons and mechanisms for this cell cycle arrest are unknown. Here, we have tried to address these questions. We reached three conclusions from our studies. First, the observed cell cycle arrest is the result of the cooperation of at least two distinct mechanisms: one involving the activation of the DNA damage response (DDR) cascade; and the other relying on the transcriptional downregulation of Hsl1, a kinase that modulates the G2/M transition. Second, a sustained cell cycle arrest during the infective filament step is necessary for the virulence in U. maydis, as a strain unable to arrest the cell cycle was severely impaired in its ability to infect corn plants. Third, production of the appressorium, a structure required for plant penetration, is incompatible with an active cell cycle. The inability to infect plants by strains defective in cell cycle arrest seems to be caused by their failure to induce the appressorium formation process. In summary, our findings uncover genetic circuits to arrest the cell cycle during the growth of this fungus on the plant surface, thus allowing the penetration into plant tissue.

  8. A CRISPR-Cas9 System for Genetic Engineering of Filamentous Fungi

    DEFF Research Database (Denmark)

    Nødvig, Christina Spuur; Nielsen, Jakob Blæsbjerg; Kogle, Martin Engelhard

    2015-01-01

    there is a demand for developing versatile methods that can be used to genetically manipulate non-model filamentous fungi. To facilitate this, we have developed a CRISPR-Cas9 based system adapted for use in filamentous fungi. The system is simple and versatile, as RNA guided mutagenesis can be achieved...... by transforming a target fungus with a single plasmid. The system currently contains four CRISPR- Cas9 vectors, which are equipped with commonly used fungal markers allowing for selection in a broad range of fungi. Moreover, we have developed a script that allows identification of protospacers that target gene...... used our CRISPR Cas9 system to generate a strain that contains an AACU_pyrG marker and demonstrated that the resulting strain can be used for iterative gene targeting....

  9. Cytoplasmic Dynein Is Required for the Spatial Organization of Protein Aggregates in Filamentous Fungi

    Directory of Open Access Journals (Sweden)

    Martin J. Egan

    2015-04-01

    Full Text Available Eukaryotes have evolved multiple strategies for maintaining cellular protein homeostasis. One such mechanism involves neutralization of deleterious protein aggregates via their defined spatial segregation. Here, using the molecular disaggregase Hsp104 as a marker for protein aggregation, we describe the spatial and temporal dynamics of protein aggregates in the filamentous fungus Aspergillus nidulans. Filamentous fungi, such as A. nidulans, are a diverse group of species of major health and economic importance and also serve as model systems for studying highly polarized eukaryotic cells. We find that microtubules promote the formation of Hsp104-positive aggregates, which coalesce into discrete subcellular structures in a process dependent on the microtubule-based motor cytoplasmic dynein. Finally, we find that impaired clearance of these inclusions negatively impacts retrograde trafficking of endosomes, a conventional dynein cargo, indicating that microtubule-based transport can be overwhelmed by chronic cellular stress.

  10. Citrinin derivatives from the soil filamentous fungus Penicillium sp. H9318

    Energy Technology Data Exchange (ETDEWEB)

    Guangmin, Yao [Huazhong University of Science and Technology, Wuhan (China). Tongji Medical College. Hubei Key Lab. of Natural Medicinal Chemistry and Resources Evaluation; Sebisubi, Fred Musoke [Ministry of Health, Kampala (Uganda). Div. of Pharmaceutical Services; Voo, Lok Yung Christopher; Ho, Coy Choke [University Malaysia Sabah, Sabah (Malaysia). School of Science and Technology. Biotechnology Program; Tan, Ghee Teng; Chang, Leng Chee, E-mail: lengchee@hawaii.ed [University of Hawaii Hilo, Hilo (United States). College of Pharmacy. Dept. of Pharmaceutical Sciences

    2011-07-01

    Investigation of a microbial fermentation organic extract of Penicillium sp. H9318 led to the isolation of a new isoquinolinone alkaloid, (5S)-3,4,5,7-tetramethyl-5,8-dihydroxyl-6(5H)- isoquinolinone (1), along with four known citrinin derivatives (2-5). Citrinin (2) exhibited significant inhibitory activity against Streptomyces 85E in the hyphae formation inhibition (HFI) assay, while compounds 1, 3-5 were not active when tested at 20 {mu}g/disk in the HFI assay. Citrinin (2) further demonstrated a weak inhibitory activity against MCF-7 (IC{sub 50} 71.93 {mu}mol L{sup -1}), LNCaP (IC{sub 50} 77.92 {mu}mol L{sup -1}), LU-1 (147.85 {mu}mol L{sup -1}) and KB (IC{sub 50} 65.93 {mu}mol L{sup -1}) cell lines, respectively, in the cytotoxicity assay. (author)

  11. Tributyltin (TBT) induces oxidative stress and modifies lipid profile in the filamentous fungus Cunninghamella elegans.

    Science.gov (United States)

    Bernat, Przemysław; Gajewska, Ewa; Szewczyk, Rafał; Słaba, Mirosława; Długoński, Jerzy

    2014-03-01

    To investigate the response of the tributyltin-degrading fungal strain Cunninghamella elegans to the organotin, a comparative lipidomics strategy was employed using an LC/MS-MS technique. A total of 49 lipid species were identified. Individual phospholipids were then quantified using a multiple reaction monitoring method. Tributyltin (TBT) caused a decline in the amounts of many molecular species of phosphatidylethanolamine or phosphatidylserine and an increase in the levels of phosphatidic acid, phosphatidylinositol and phosphatidylcholine. In the presence of TBT, it was observed that overall unsaturation was lower than in the control. Lipidome data were analyzed using principal component analysis, which confirmed the compositional changes in membrane lipids in response to TBT. Additionally, treatment of fungal biomass with butyltin led to a significant increase in lipid peroxidation. It is suggested that modification of the phospholipids profile and lipids peroxidation may reflect damage to mycelium caused by TBT.

  12. Mutations affecting mitotic recombination frequency in haploids and diploids of the filamentous fungus Aspergillus nidulans.

    Science.gov (United States)

    Parag, Y; Parag, G

    1975-01-01

    A haploid strain of Asp. nidulans with a chromosome segment in duplicate (one in normal position on chromosome I, one translocated to chromosome II) shows mitotic recombination, mostly by conversion, in adE in a frequency slightly higher than in the equivalent diploid. A method has been devised, using this duplication, for the selection of rec and uvs mutations. Six rec mutations have been found which decrease recombination frequency in the haploid. One mutation selected as UV sensitive showed a hundred fold increase in recombination frequency in the haploid (pop mutation) and probably the same in diploids. The increased frequency is both in gene conversion and in crossing over, and the exchanges appear in clusters of two or more. pop is allelic to uvsB (Jansen, 1970) which had been found to affect mitotic but not meiotic recombination. It is suggested that mutations of this type interfere with the control mechanism which determines that high recombination is confirmed to the meiotic nuclei and avoided in somatic nuclei.

  13. Reducing fitness costs associated with antibiotic resistance: experimental evolution in the filamentous fungus Aspergillus nidulans

    NARCIS (Netherlands)

    Schoustra, S.E.

    2004-01-01

    The 1990s saw the growth of two distinct strands of debates on the transformations and emerging problems besetting the urban space. One of these has focused on the relationship between globalisation and the similar changes metropolitan cities are undergoing, as they become home to numerous global ec

  14. Frequency and Distribution of Microsatellites in the Genome of Filamentous Fungus, Neurospora crassa

    Institute of Scientific and Technical Information of China (English)

    LI Cheng-yun; LI Jin-bin; ZHOU Xiao-gang; ZHANG Shao-song; XU Ming-hui

    2005-01-01

    A total of 38.0 Mb of publicly available DNA sequence in Neurospora crassa was researched for mono- to hexanucleotide simple sequence repeats (SSR or microsatellite) to determine the type, size and frequency. A total of 14 788 SSRs were observed in the whole genomic DNA sequence, about one every 2.57 kb, with the criteria of SSR length >15 bp and 80%matches. The most abundant microsatellite was trinucleotide repeat, the number was 4 729, followed by hexanucleotide and mononucleotide repeats, the numbers were 2 940 and 2 489 respectively, and the least abundance was dinucleotide repeat, only 691 were found. Among the 10 082 ORFs, 4 094 SSRs were harbored in 2 373 ORF (no intron) of the organism.One thousand and fifty six ORFs harbored only one SSR. Similar with other organisms, tri- and hexanucleotide repeats were predominant in ORFs, 54.1 and 48.8% oftri- and hexanucleotide repeats were distributed in ORF region. The density of these two motifs was overpresented in coding regions, because ORF region and coding region constitutes only 46 and 38.3% of genomic sequence, respectively. Upstream and downstream 300 bp of regulatory regions were high density regions of SSRs, particularly density of pentanucleotide SSR in upstream region was as high as five times of average density in genomic DNA, density of di- and tetranucleotide SSR was also more than two times of average density. The density of penta-, tetra-, di- and mononucleotide SSRs was relatively higher than average density. There were 47 SSRs in mitochondria 64 840 bp DNA sequence, their distribution is similar with genomic DNA sequence. These results suggested that SSRs were clustered in regulatory regions of genomic DNA.

  15. Mutations affecting extracellular protease production in the filamentous fungus Aspergillus nidulans.

    Science.gov (United States)

    Katz, M E; Flynn, P K; vanKuyk, P A; Cheetham, B F

    1996-04-10

    The extracellular proteases of Aspergillus nidulans are known to be regulated by carbon, nitrogen and sulphur metabolite repression. In this study, a mutant with reduced levels of extracellular protease was isolated by screening for loss of halo production on milk plates. Genetic analysis of the mutant showed that it contains a single, recessive mutation, in a gene which we have designated xprE, located on chromosome VI. The xprE1 mutation affected the production of extracellular proteases in response to carbon, nitrogen and, to a lesser extent, sulphur limitation. Three reversion mutations, xprF1, xprF2 and xprG1, which suppress xprE1, were characterised. Both xprF and xprG map to chromosome VII but the two genes are unlinked. The xprF1, xprF2 and xprG1 mutants showed high levels of milk-clearing activity on medium containing milk as a carbon source but reduced growth on a number of nitrogen sources. Evidence is presented that the xprE1 and xprG1 mutations alter expression of more than one protease and affect levels of alkaline protease gene mRNA.

  16. Growth inhibition of the filamentous fungus Aspergillus nidulans by cadmium: an antioxidant enzyme approach.

    Science.gov (United States)

    Guelfi, Andrea; Azevedo, Ricardo A; Lea, Peter J; Molina, Silvia M G

    2003-04-01

    The heavy metal cadmium is very toxic to biological systems. Although its effect on the growth of microorganisms and plants has been investigated, the response of antioxidant enzymes of Aspergillus nidulans to cadmium is not well documented. We have studied the effect of cadmium (supplied as CdCl(2)) on catalase (CAT), superoxide dismutase (SOD) and glutathione reductase (GR). 0.005 mM CdCl(2) had a very slight stimulatory effect on the growth rate of A. nidulans, but at concentrations above 0.025 mM, growth was totally inhibited. The accumulation of Cd within the mycelium was directly correlated with the increase in the concentration of CdC(2) used in the treatments. Although a cadmium-stimulated increase in SOD activity was observed, there was no change in the relative proportions of the individual Mn-SOD isoenzymes. Higher concentrations of CdCl(2) induced a small increase in total CAT activity, but there was a major increase in one isoenzymic form, that could be separated by gel electrophoresis. GR activity increased significantly following treatment with the highest concentration (0.05 mM) of CdCl(2). The increases in SOD, CAT, and GR activities suggest that CdCl(2) induces the formation of reactive oxygen species inside the mycelia of A. nidulans.

  17. A Sandwiched-Culture Technique for Evaluation of Heterologous Protein Production in a Filamentous Fungus

    Science.gov (United States)

    Ásgeirsdóttir, Sigrídur A.; Scholtmeijer, Karin; Wessels, Joseph G. H.

    1999-01-01

    Aspergillus niger is known for its efficient excretion machinery. However, problems have often arisen in obtaining high amounts of heterologous proteins in the culture medium. Here we present a quick method using sandwiched colonies to evaluate transgenic strains for secretion of heterologous proteins. Expressing the ABH1 hydrophobin of Agaricus bisporus in A. niger, we showed that low production levels of the heterologous protein are probably due to extracellular proteolytic degradation of the protein. PMID:10224030

  18. A sandwiched-culture technique for evaluation of heterologous protein production in a filamentous fungus

    NARCIS (Netherlands)

    Asgeirsdottir, SA; Scholtmeijer, K; Wessels, JGH

    1999-01-01

    Aspergillus niger is known for its efficient excretion machinery. However, problems have often arisen in obtaining high amounts of heterologous proteins in the culture medium. Here we present a quick method using sandwiched colonies to evaluate transgenic strains for secretion of heterologous protei

  19. Direct fermentation of cellulose to ethanol by a cellulolytic filamentous fungus, monilia sp

    Energy Technology Data Exchange (ETDEWEB)

    Gong, C.S.; Maun, C.M.; Tsao, G.T.

    1981-01-01

    Monilia, isolated from bagasse compost, utilized many polysaccharides (including cellulose) and displayed cellulase and hemicellulase activities. Monilia also fermented glucose, xylose, and cellulosic materials to ethanol. Over 60% of the solid cellulose substrate added to Monilia cultures was converted to ethanol as the major fermentation product. Thus, Monilia is a potential organism for the direct conversion of cellulosic biomass to ethanol.

  20. Structural features of sugars that trigger or support conidial germination in the filamentous fungus Aspergillus niger.

    Science.gov (United States)

    Hayer, Kimran; Stratford, Malcolm; Archer, David B

    2013-11-01

    The asexual spores (conidia) of Aspergillus niger germinate to produce hyphae under appropriate conditions. Germination is initiated by conidial swelling and mobilization of internal carbon and energy stores, followed by polarization and emergence of a hyphal germ tube. The effects of different pyranose sugars, all analogues of d-glucose, on the germination of A. niger conidia were explored, and we define germination as the transition from a dormant conidium into a germling. Within germination, we distinguish two distinct stages, the initial swelling of the conidium and subsequent polarized growth. The stage of conidial swelling requires a germination trigger, which we define as a compound that is sensed by the conidium and which leads to catabolism of d-trehalose and isotropic growth. Sugars that triggered germination and outgrowth included d-glucose, d-mannose, and d-xylose. Sugars that triggered germination but did not support subsequent outgrowth included d-tagatose, d-lyxose, and 2-deoxy-d-glucose. Nontriggering sugars included d-galactose, l-glucose, and d-arabinose. Certain nontriggering sugars, including d-galactose, supported outgrowth if added in the presence of a complementary triggering sugar. This division of functions indicates that sugars are involved in two separate events in germination, triggering and subsequent outgrowth, and the structural features of sugars that support each, both, or none of these events are discussed. We also present data on the uptake of sugars during the germination process and discuss possible mechanisms of triggering in the absence of apparent sugar uptake during the initial swelling of conidia.

  1. Grafting as a method for studying development in the filamentous fungus Podospora anserina.

    Science.gov (United States)

    Silar, Philippe

    2011-08-01

    While grafting and transplant experiments have extensively been used to study development in animals and plants, they have seldom been employed to study fungal development. Here, grafting is used to study the interplay between mycelium and multicellular fruiting bodies during maturation in the model ascomycete Podospora anserina. Data indicate that grafts need a competent mycelium to continue their ripening. Vegetative incompatibility does not prevent transplanted fructifications to undergo development. Grafting onto mutant mycelia confirmed a previous model stating that the NADPH oxidase PaNox1 is required in the developing fruiting bodies, while the MAP kinase cascade PaMpk1 is required in the mycelium. Data also show that the IDC1 protein is required not only in the developing fruiting bodies but also in the mycelium, likely because of its role in anastomosis. Finally, entry inside the grafted fruiting bodies of a ribosomal protein tagged with GFP could be detected, suggesting that cellular components are imported from the underlying mycelium during maturation.

  2. Molecular Mechanisms Regulating Sporulation in the Filamentous Fungus Ashbya gossypii

    DEFF Research Database (Denmark)

    Wasserstrom, Lisa

    Sporulation is a complex developmental program that fungi enter to ensure survival in unfavorable environmental conditions. Many fungal species are able to produce spores sexually through meiosis, which is beneficial since it introduces genetic variability into a population. The sexually reproduc......Sporulation is a complex developmental program that fungi enter to ensure survival in unfavorable environmental conditions. Many fungal species are able to produce spores sexually through meiosis, which is beneficial since it introduces genetic variability into a population. The sexually...... reproducing ascomycete Saccharomyces cerevisiae has a well-defined sexual cycle, in which diploid cells can undergo meiosis and produce haploid spores in response to nutrient starvation. The diploid state is a requirement for meiosis and results from fusion of two haploid cells of the opposite mating type...... negatively instead of controlling mating. In line with this, a mating partner might not be required since the multinucleate compartments could still enable nuclear fusion (karyogamy) and meiosis. The presence of karyogamy is supported by our results that deletion of the A. gossypii homologs Kar3 and Kar4...

  3. A glucose-derepressed promoter for expression of heterologous products in the filamentous fungus Aspergillus nidulans.

    Science.gov (United States)

    Hintz, W E; Lagosky, P A

    1993-07-01

    We describe a putative binding sequence (GCGGGGC) for the glucose-responsive repressor protein CreA at two positions upstream of the transcription start site of the alcohol dehydrogenase I (alcA) gene of Aspergillus nidulans. To positively identify the putative binding sites as CreA-specific, the GCGGGGC blocks were mutated at five internal nucleotide positions to GTACTAC and reintroduced into the wild type alcA promoter driving expression of the endogenous alcohol dehydrogenase I gene. This CreA-binding site variant was then transformed into an AlcR constitutive A. nidulans host strain (T2625) and growth was monitored in the presence of the non-metabolized glucose analogue, 2-deoxyglucose. Positive transformants were selected by their ability to grow using ethanol as a carbon source in the presence of 2-deoxyglucose. Similar CreA binding site variant alcA promoters should permit the alcA-driven expression of heterologous genes in A. nidulans in the presence of glucose, the preferred carbon source for biomass accumulation and provides a model for controlling carbon-catabolite regulated expression in other expression systems.

  4. Can hTNF-alpha be successfully produced and secreted in filamentous fungus Aspergillus niger?

    NARCIS (Netherlands)

    Krasevec, N.; Hondel, C.A.M.J.J. van den; Komel, R.

    2000-01-01

    A gene-fusion expression strategy was applied for the heterologous expression of hTNF-α in A. niger AB1.13. The TNF-α gene was fused with the A. niger glucoamylase GII form as a carrier-gene, behind its transcription control and secretion signal. The protein was expressed in the cells in the form of

  5. Studying Pellet Formation of a Filamentous Fungus Rhizopus oryzae to Enhance Organic Acid Production

    Science.gov (United States)

    Liao, Wei; Liu, Yan; Chen, Shulin

    Using pelletized fungal biomass can effectively improve the fermentation performance for most of fugal strains. This article studied the effects of inoculum and medium compositions such as potato dextrose broth (PDB) as carbon source, soybean peptone, calcium carbonate, and metal ions on pellet formation of Rhizopus oryzae. It has been found that metal ions had significantly negative effects on pellet formation whereas soybean peptone had positive effects. In addition PDB and calcium carbonate were beneficial to R. oryzae for growing small smooth pellets during the culture. The study also demonstrated that an inoculum size of less than 1.5×109 spores/L had no significant influence on pellet formation. Thus, a new approach to form pellets has been developed using only PDB, soybean peptone, and calcium carbonate. Meanwhile, palletized fungal fermentation significantly enhanced organic acid production. Lactic acid concentration reached 65.0 g/L in 30 h using pelletized R. oryzae NRRL 395, and fumeric acid concentration reached 31.0 g/L in 96 h using pelletized R. oryzae ATCC 20344.

  6. Assessment of the microbody luminal pH in the filamentous fungus Penicillium chrysogenum

    NARCIS (Netherlands)

    Lende, Ted R. van der; Breeuwer, Pieter; Abee, Tjakko; Konings, Wil N.; Driessen, Arnold J.M.

    2002-01-01

    The enzymes of the penicillin biosynthetic pathway in Penicillium chrysogenum are located in different subcellular compartments. Consequently, penicillin pathway precursors and the biologically active penicillins have to cross one or more membranes. The final enzymatic step that is mediated by acylt

  7. A novel fast mass transfer anaerobic inner loop fluidized bed biofilm reactor for PTA wastewater treatment.

    Science.gov (United States)

    Chen, Yingwen; Zhao, Jinlong; Li, Kai; Xie, Shitao

    In this paper, a fast mass transfer anaerobic inner loop fluidized bed biofilm reactor (ILFBBR) was developed to improve purified terephthalic acid (PTA) wastewater treatment. The emphasis of this study was on the start-up mode of the anaerobic ILFBBR, the hydraulic loadings and the operation stability. The biological morphology of the anaerobic biofilm in the reactors was also analyzed. The anaerobic column could operate successfully for 46 days due to the pre-aerating process. The anaerobic column had the capacity to resist shock loadings and maintained a high stable chemical oxygen demand (COD) and terephthalic acid removal rates at a hydraulic retention time of 5-10 h, even under conditions of organic volumetric loadings as high as 28.8 kg COD·m(-3).d(-1). The scanning electron microscope analysis of the anaerobic carrier demonstrated that clusters of prokaryotes grew inside of pores and that the filaments generated by pre-aeration contributed to the anaerobic biofilm formation and stability.

  8.   The fungus Trichoderma spp. on vegetables

    DEFF Research Database (Denmark)

    Winding, Anne

      The fungus Trichoderma spp. on vegetables   Anne Winding, National Environmental Research Institute, Roskilde, AU   Trichoderma spp. is a naturally occurring fungus in soil and T. harzianum is an active ingredient in microbial pest control agents (MPCA) active against root pathogenic fungi....... The MPCA is administered to the plants by watering. The fungus establishes in the root zone and exerts its beneficial effect by general increase of resistance against pathogenic fungi. The natural occurrence of Trichoderma spp. and the fate and survival of the introduced T. harzianum on vegetables...

  9. Microsatellite Primers for Fungus-Growing Ants

    DEFF Research Database (Denmark)

    Villesen Fredsted, Palle; Gertsch, Pia J.; Boomsma, Jacobus Jan (Koos)

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  10. Microsatellite primers for fungus-growing ants

    DEFF Research Database (Denmark)

    Villesen, Palle; Gertsch, P J; Boomsma, JJ

    2002-01-01

    We isolated five polymorphic microsatellite loci from a library of two thousand recombinant clones of two fungus-growing ant species, Cyphomyrmex longiscapus and Trachymyrmex cf. zeteki. Amplification and heterozygosity were tested in five species of higher attine ants using both the newly...... developed primers and earlier published primers that were developed for fungus-growing ants. A total of 20 variable microsatellite loci, developed for six different species of fungus-growing ants, are now available for studying the population genetics and colony kin-structure of these ants....

  11. Mechanical properties of branched actin filaments

    CERN Document Server

    Razbin, Mohammadhosein; Benetatos, Panayotis; Zippelius, Annette

    2015-01-01

    Cells moving on a two dimensional substrate generate motion by polymerizing actin filament networks inside a flat membrane protrusion. New filaments are generated by branching off existing ones, giving rise to branched network structures. We investigate the force-extension relation of branched filaments, grafted on an elastic structure at one end and pushing with the free ends against the leading edge cell membrane. Single filaments are modeled as worm-like chains, whose thermal bending fluctuations are restricted by the leading edge cell membrane, resulting in an effective force. Branching can increase the stiffness considerably; however the effect depends on branch point position and filament orientation, being most pronounced for intermediate tilt angles and intermediate branch point positions. We describe filament networks without cross-linkers to focus on the effect of branching. We use randomly positioned branch points, as generated in the process of treadmilling, and orientation distributions as measur...

  12. Protein profiling of the dimorphic, pathogenic fungus, Penicillium marneffei

    Directory of Open Access Journals (Sweden)

    Rundle William T

    2008-06-01

    Full Text Available Abstract Background Penicillium marneffei is a pathogenic fungus that afflicts immunocompromised individuals having lived or traveled in Southeast Asia. This species is unique in that it is the only dimorphic member of the genus. Dimorphism results from a process, termed phase transition, which is regulated by temperature of incubation. At room temperature, the fungus grows filamentously (mould phase, but at body temperature (37°C, a uninucleate yeast form develops that reproduces by fission. Formation of the yeast phase appears to be a requisite for pathogenicity. To date, no genes have been identified in P. marneffei that strictly induce mould-to-yeast phase conversion. In an effort to help identify potential gene products associated with morphogenesis, protein profiles were generated from the yeast and mould phases of P. marneffei. Results Whole cell proteins from the early stages of mould and yeast development in P. marneffei were resolved by two-dimensional gel electrophoresis. Selected proteins were recovered and sequenced by capillary-liquid chromatography-nanospray tandem mass spectrometry. Putative identifications were derived by searching available databases for homologous fungal sequences. Proteins found common to both mould and yeast phases included the signal transduction proteins cyclophilin and a RACK1-like ortholog, as well as those related to general metabolism, energy production, and protection from oxygen radicals. Many of the mould-specific proteins identified possessed similar functions. By comparison, proteins exhibiting increased expression during development of the parasitic yeast phase comprised those involved in heat-shock responses, general metabolism, and cell-wall biosynthesis, as well as a small GTPase that regulates nuclear membrane transport and mitotic processes in fungi. The cognate gene encoding the latter protein, designated RanA, was subsequently cloned and characterized. The P. marneffei RanA protein

  13. Solubilization and fractionation of paired helical filaments.

    Science.gov (United States)

    González, P J; Correas, I; Avila, J

    1992-09-01

    Paired helical filaments isolated from brains of two different patients with Alzheimer's disease were extensively treated with the ionic detergent, sodium dodecyl sulphate. Filaments were solubilized at different extents, depending on the brain examined, thus suggesting the existence of two types of paired helical filaments: sodium dodecyl sulphate-soluble and insoluble filaments. In the first case, the number of structures resembling paired helical filaments greatly decreased after the detergent treatment, as observed by electron microscopy. Simultaneously, a decrease in the amount of sedimentable protein was also observed upon centrifugation of the sodium dodecyl sulfate-treated paired helical filaments. A sodium dodecyl sulphate-soluble fraction was isolated as a supernatant after low-speed centrifugation of the sodium dodecyl sulphate-treated paired helical filaments. The addition of the non-ionic detergent Nonidet-P40 to this fraction resulted in the formation of paired helical filament-like structures. When the sodium dodecyl sulphate-soluble fraction was further fractionated by high-speed centrifugation, three subfractions were observed: a supernatant, a pellet and a thin layer between these two subfractions. No paired helical filaments were observed in any of these subfractions, even after addition of Nonidet P-40. However, when they were mixed back together, the treatment with Nonidet P-40 resulted in the visualization of paired helical filament-like structures. These results suggest that at least two different components are needed for the reconstitution of paired helical filaments as determined by electron microscopy. The method described here may allow the study of the components involved in the formation of paired helical filaments and the identification of possible factors capable of blocking this process.

  14. Accumulation and chemical states of radiocesium by fungus Saccharomyces cerevisiae

    Science.gov (United States)

    Ohnuki, Toshihiko; Sakamoto, Fuminori; Kozai, Naofumi; Yamasaki, Shinya; Yu, Qianqian

    2014-05-01

    After accident of Fukushima Daiichi Nuclear Power Plant, the fall-out radiocesium was deposited on the ground. Filamentous fungus is known to accumulate radiocesium in environment, even though many minerals are involved in soil. These facts suggest that fungus affect the migration behavior of radiocesium in the environment. However, accumulation mechanism of radiocesium by fungus is not understood. In the present study, accumulation and chemical states change of Cs by unicellular fungus of Saccharomyces cerevisiae have been studied to elucidate the role of microorganisms in the migration of radiocesium in the environment. Two different experimental conditions were employed; one is the accumulation experiments of radiocesium by S. cerevisiae from the agar medium containing 137Cs and a mineral of zeolite, vermiculite, smectite, mica, or illite. The other is the experiments using stable cesium to examine the chemical states change of Cs. In the former experiment, the cells were grown on membrane filter of 0.45 μm installed on the agar medium. After the grown cells were weighed, radioactivity in the cells was measured by an autoradiography technique. The mineral weight contents were changed from 0.1% to 1% of the medium. In the latter experiment, the cells were grown in the medium containing stable Cs between 1 mM and 10mM. The Cs accumulated cells were analyzed by SEM-EDS and EXAFS. The adsorption experiments of cesium by the cells under resting condition were also conducted to test the effect of cells metabolic activity. Without mineral in the medium, cells of S. cerevisiae accumulated 1.5x103 Bq/g from the medium containing 137Cs of 2.6x102 Bq/g. When mineral was added in the medium, concentration of 137Cs in the cells decreased. The concentration of 137Cs in the cells from the medium containing different minerals were in the following order; smectite, illite, mica > vermiculite > zeolite. This order was nearly the same as the inverse of distribution coefficient of

  15. Entomology: A Bee Farming a Fungus.

    Science.gov (United States)

    Oldroyd, Benjamin P; Aanen, Duur K

    2015-11-16

    Farming is done not only by humans, but also by some ant, beetle and termite species. With the discovery of a stingless bee farming a fungus that provides benefits to its larvae, bees can be added to this list.

  16. A New Macrocyclic Trichochecene from Soil Fungus

    Institute of Scientific and Technical Information of China (English)

    TaoWANG; YiZHANG; 等

    2002-01-01

    From fermentation broth of soil fungus 254-2 obtained from Yunnan province, a new macrocylic trichochecene was isolated. The structure was determined on the basis of spectroscopie evidences especially the 2-D NMR spectra.

  17. A new macrocyclic trichochecene from soil fungus

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    From fermentation broth of soil fungus 254-2 obtained from Yunnan province,a new macrocylic trichochecene was isolated.The structure was determined on the basis of spectroscopic evidences especially the 2-D NMR spectra.

  18. Metabolites from marine fungus Aspergillus sp.

    Digital Repository Service at National Institute of Oceanography (India)

    Wahidullah, S.; Rajmanickam, R.; DeSouza, L.

    Chemical examination of a methanolic extract of the marine fungus, Aspergillus sp., isolated from marine grass environment, yielded a steroid, ergosterol peroxide (1), and a mixture of known glyceride esters (2,3) of unsaturated fatty acids...

  19. Equilibrium shapes of twisted magnetic filaments

    Energy Technology Data Exchange (ETDEWEB)

    Belovs, Mihails; Cirulis, Teodors; Cebers, Andrejs [University of Latvia, Zellu 8, LV-1002 (Latvia)], E-mail: aceb@tesla.sal.lv

    2009-06-12

    It is shown that ferromagnetic filaments with free and unclamped ends undergo buckling instabilities under the action of twist. Solutions of nonlinear equations describing the buckled shapes are found, and it is shown that the transition to the buckled shape is subcritical if the magnetization is parallel to the field and supercritical when the magnetization of the straight filament is opposite to the external field. Solutions with the localized curvature distribution are found in the case of long filaments. The class of solutions corresponding to helices is described, and the behavior of coiled ferromagnetic and superparamagnetic filaments is compared.

  20. Hydrodynamic interactions between nearby slender filaments

    CERN Document Server

    Man, Yi; Lauga, Eric

    2016-01-01

    Cellular biology abound with filaments interacting through fluids, from intracellular microtubules, to rotating flagella and beating cilia. While previous work has demonstrated the complexity of capturing nonlocal hydrodynamic interactions between moving filaments, the problem remains difficult theoretically. We show here that when filaments are closer to each other than their relevant length scale, the integration of hydrodynamic interactions can be approximately carried out analytically. This leads to a set of simplified local equations, illustrated on a simple model of two interacting filaments, which can be used to tackle theoretically a range of problems in biology and physics.

  1. Deep coronal hole associated with quiescent filament

    Science.gov (United States)

    Kesumaningrum, Rasdewita; Herdiwidjaya, Dhani

    2014-03-01

    We present a study of the morphology of quiescent filament observed by H-alpha Solar Telescope at Bosscha Observatory in association with coronal hole observed by Atmospheric Imaging Assembly (AIA) instrument in 193 Å from Solar Dynamics Observatory. H-alpha images were processed by imaging softwares, namely Iris 5.59 and ImageJ, to enhance the signal to noise ratio and to identify the filament features associated with coronal hole. For images observed on October 12, 2011, November 14, 2011 and January 2, 2012, we identified distinct features of coronal holes above the quiescent filaments. This associated coronal holes have filament-like morphology with a thick long thread as it's `spine', defined as Deep Coronal Hole. Because of strong magnetic field of sunspot, these filaments and coronal holes emerged far from active region and lasted for several days. It is interesting as for segmented filament, deep coronal holes above the filaments lasted for a quite long period of time and merged. This association between filament and deep coronal hole can be explained by filament magnetic loop.

  2. Probing the Physical Structures of Dense Filaments

    Science.gov (United States)

    Li, Di

    2015-08-01

    Filament is a common feature in cosmological structures of various scales, ranging from dark matter cosmic web, galaxy clusters, inter-galactic gas flows, to Galactic ISM clouds. Even within cold dense molecular cores, filaments have been detected. Theories and simulations with (or without) different combination of physical principles, including gravity, thermal balance, turbulence, and magnetic field, can reproduce intriguing images of filaments. The ubiquity of filaments and the similarity in simulated ones make physical parameters, beyond dust column density, a necessity for understanding filament evolution. I report three projects attempting to measure physical parameters of filaments. We derive the volume density of a dense Taurus filament based on several cyanoacetylene transitions observed by GBT and ART. We measure the gas temperature of the OMC 2-3 filament based on combined GBT+VLA ammonia images. We also measured the sub-millimeter polarization vectors along OMC3. These filaments were found to be likely a cylinder-type structure, without dynamic heating, and likely accreting mass along the magnetic field lines.

  3. New perspectives in anaerobic digestion

    DEFF Research Database (Denmark)

    van Lier, J.B.; Tilche, A.; Ahring, Birgitte Kiær;

    2001-01-01

    The IWA specialised group on anaerobic digestion (AD) is one of the oldest working groups of the former IAWQ organisation. Despite the fact that anaerobic technology dates back more than 100 years, the technology is still under development, adapting novel treatment systems to the modern...... requirements. In fact, most advances were achieved during the last three decades, when high-rate reactor systems were developed and a profound insight was obtained in the microbiology of the anaerobic communities. This insight led to a better understanding of anaerobic treatment and, subsequently, to a broader...

  4. Anaerobic oxidation of methane above gas hydrates at Hydrate Ridge, NE Pacific Ocean

    DEFF Research Database (Denmark)

    Treude, T.; Boetius, A.; Knittel, K.;

    2003-01-01

    At Hydrate Ridge (HR), Cascadia convergent margin, surface sediments contain massive gas hydrates formed from methane that ascends together with fluids along faults from deeper reservoirs. Anaerobic oxidation of methane (AOM), mediated by a microbial consortium of archaea and sulfate-reducing...... bacteria, generates high concentrations of hydrogen sulfide in the surface sediments. The production of sulfide supports chemosynthetic communities that gain energy from sulfide oxidation. Depending on fluid flow, the surface communities are dominated either by the filamentous sulfur bacteria Beggiatoa...

  5. A Statistical Study of Solar Filament Eruptions

    Science.gov (United States)

    Schanche, Nicole; Aggarwal, Ashna; Reeves, Kathy; Kempton, Dustin James; Angryk, Rafal

    2016-05-01

    Solar filaments are cool, dark channels of partially-ionized plasma that lie above the chromosphere. Their structure follows the neutral line between local regions of opposite magnetic polarity. Previous research (e.g. Schmieder et al. 2013, McCauley et al. 2015) has shown a positive correlation (70-80%) between the occurrence of filament eruptions and coronal mass ejections (CME’s). In this study, we attempt to use properties of the filament in order to predict whether or not a given filament will erupt. This prediction would help to better predict the occurrence of an oncoming CME. To track the evolution of a filament over time, a spatio-temporal algorithm that groups separate filament instances from the Heliophysics Event Knowledgebase (HEK) into filament tracks was developed. Filament features from the HEK metadata, such as length, chirality, and tilt are then combined with other physical features, such as the overlying decay index for two sets of filaments tracks - those that erupt and those that remain bound. Using statistical methods such as the Kolmogrov-Smirnov test and a Random Forest Classifier, we determine the effectiveness of the combined features in prediction. We conclude that there is significant overlap between the properties of filaments that erupt and those that do not, leading to predictions only ~5-10% above chance. However, the changes in features, such as a change in the filament's length over time, were determined to have the highest predictive power. We discuss the possible physical connections with the change in these features."This project has been supported by funding from the Division of Advanced Cyberinfrastructure within the Directorate for Computer and Information Science and Engineering, the Division of Astronomical Sciences within the Directorate for Mathematical and Physical Sciences, and the Division of Atmospheric and Geospace Sciences within the Directorate for Geosciences, under NSF award #1443061.”

  6. Sequential saccharification of corn fiber and ethanol production by the brown rot fungus Gloeophyllum trabeum.

    Science.gov (United States)

    Rasmussen, M L; Shrestha, P; Khanal, S K; Pometto, A L; Hans van Leeuwen, J

    2010-05-01

    Degradation of lignocellulosic biomass to sugars through a purely biological process is a key to sustainable biofuel production. Hydrolysis of the corn wet-milling co-product-corn fiber-to simple sugars by the brown rot fungus Gloeophyllum trabeum was studied in suspended-culture and solid-state fermentations. Suspended-culture experiments were not effective in producing harvestable sugars from the corn fiber. The fungus consumed sugars released by fungal extracellular enzymes. Solid-state fermentation demonstrated up to 40% fiber degradation within 9days. Enzyme activity assays on solid-state fermentation filtrates confirmed the involvement of starch- and cellulose-degrading enzymes. To reduce fungal consumption of sugars and to accelerate enzyme activity, 2- and 3-d solid-state fermentation biomasses (fiber and fungus) were submerged in buffer and incubated at 37 degrees C without shaking. This anaerobic incubation converted up to almost 11% of the corn fiber into harvestable reducing sugars. Sugars released by G. trabeum were fermented to a maximum yield of 3.3g ethanol/100g fiber. This is the first report, to our knowledge, of G. trabeum fermenting sugar to ethanol. The addition of Saccharomyces cerevisiae as a co-culture led to more rapid fermentation to a maximum yield of 4.0g ethanol/100g fiber. The findings demonstrate the potential for this simple fungal process, requiring no pretreatment of the corn fiber, to produce more ethanol by hydrolyzing and fermenting carbohydrates in this lignocellulosic co-product.

  7. Biotransformation of metoprolol by the fungus Cunninghamella blakes-leeana

    Institute of Scientific and Technical Information of China (English)

    Bin MA; Hai-hua HUANG; Xiao-yan CHEN; Yu-ming SUN; Li-hong LIN; Da-fang ZHONG

    2007-01-01

    Aim: To investigate the biotransformation of metoprolol, a β1-cardioselective adrenoceptor antagonist, by filamentous fungus, and to compare the parallels between microbial transformation and mammalian metabolism. Methods: Five strains of Cunninghamella (C elegans AS 3.156, C elegans AS 3.2028, C echinulata AS 3.2004, C blakesleeana AS 3.153 and AS 3.910) were screened for the ability to transform metoprolol. The metabolites of metoprolol produced by C blakesleeana AS 3.153 were separated and assayed by liquid chromatography-tandem mass spectrometry (LC/MSn). The major metabolites were isolated by semipreparative HPLC and the structures were identified by a combination of LC/MSn and nuclear magnetic resonance analysis. Results: Metoprolol was transformed to 7 metabolites; 2 were identified as new metabolites and 5 were known metabolites in mammals. Conclusion: The microbial transformation of metoprolol was similar to the metabolism in mammals. The fungi belonging to Cunninghamella species could be used as complementary models for predicting in vivo metabolism and producing quantities of metabolite references for drugs like metoprolol.

  8. Biotransformation of indomethacin by the fungus Cunninghamella blakesleeana

    Institute of Scientific and Technical Information of China (English)

    Peng ZHANG; Li-hong LIN; Hai-hua HUANG; Hai-yan XU; Da-fang ZHONG

    2006-01-01

    Aim: To investigate the biotransformation of indomethacin, the first of the newer nonsteroidal anti-inflammatory drugs, by filamentous fungus and to compare the similarities between microbial transformation and mammalian metabolism of indomethacin. Methods: Five strains of Cunninghamella (C elegans AS 3.156, C elegans AS 3.2028, C blakesleeana AS 3.153, C blakesleeana AS 3.910 and C echinulata AS 3.2004) were screened for their ability to catalyze the biotransformation of indomethacin. Indomethacin was partially metabolized by five strains of Cunninghamella, and C blakesleeana AS 3.910 was selected for further investigation. Three metabolites produced by C blakesleeana AS 3.910 were isolated using semi-preparative HPLC, and their structures were identified by a combination analysis of LC/MSn and NMR spectra. These three metabolites were separated and quantitatively assayed by liquid chromatography-ion trap mass spectrometry. Results: After 120 h of incubation with C blakesleeana AS 3.910, approximately 87.4% of indomethacin was metabolized to three metabolites: O-desmethylindomethacin (DMI, M1, 67.2%), Af-deschlorobenzoylindomethacin (DBI, M2,13.3%) and O-desmethyl-AT-deschlorobenzoylindomethacin (DMBI, M3, 6.9%). Three phase I metabolites of indomethacin produced by C blakesleeana AS 3.910 were identical to those obtained in humans. Conclusion: C blakesleeana could be a useful tool for generating the mammalian phase I metabolites of indomethacin.

  9. The role of Bgl2p in the transition to filamentous cells during biofilm formation by Candida albicans.

    Science.gov (United States)

    Chen, Xinyue; Zhang, Ruoyu; Takada, Ayako; Iwatani, Shun; Oka, Chiemi; Kitamoto, Toshitaka; Kajiwara, Susumu

    2017-02-01

    The fungal pathogen Candida albicans undergoes a transition from yeast cells to filamentous cells that is related to its pathogenicity. The complex multicellular processes involved in biofilm formation by this fungus also include this transition. In this work, we investigated the morphological role of the Bgl2 protein (Bgl2p) in the transition to filamentous cells during biofilm formation by C. albicans. Bgl2p has been identified as a β-1, 3-glucosyltransferase, and transcription of the CaBGL2 gene is upregulated during biofilm formation. We used scanning electron microscopy to observe the microstructure of a bgl2 null mutant during biofilm formation and found a delay in the transition to filamentous cells in the premature phase (24 hours) of biofilm formation. Deletion of the CaBGL2 gene led to a decrease in the expression of CPH2 and TEC1, which encode transcription factors required for the transition to the filamentous form. These findings indicate that Bgl2p plays a role in the transition to filamentous cells during biofilm formation by C. albicans.

  10. Influence of different anoxic time exposures on active biomass, protozoa and filamentous bacteria in activated sludge.

    Science.gov (United States)

    Rodriguez-Perez, S; Fermoso, F G; Arnaiz, C

    Medium-sized wastewater treatment plants are considered too small to implement anaerobic digestion technologies and too large for extensive treatments. A promising option as a sewage sludge reduction method is the inclusion of anoxic time exposures. In the present study, three different anoxic time exposures of 12, 6 and 4 hours have been studied to reduce sewage sludge production. The best anoxic time exposure was observed under anoxic/oxic cycles of 6 hours, which reduced 29.63% of the biomass production compared with the oxic control conditions. The sludge under different anoxic time exposures, even with a lower active biomass concentration than the oxic control conditions, showed a much higher metabolic activity than the oxic control conditions. Microbiological results suggested that both protozoa density and abundance of filamentous bacteria decrease under anoxic time exposures compared to oxic control conditions. The anoxic time exposures 6/6 showed the highest reduction in both protozoa density, 37.5%, and abundance of filamentous bacteria, 41.1%, in comparison to the oxic control conditions. The groups of crawling ciliates, carnivorous ciliates and filamentous bacteria were highly influenced by the anoxic time exposures. Protozoa density and abundance of filamentous bacteria have been shown as promising bioindicators of biomass production reduction.

  11. Radial interchange motions of plasma filaments

    DEFF Research Database (Denmark)

    Garcia, O.E.; Bian, N.H.; Fundamenski, W.

    2006-01-01

    reduces the radial velocity of isolated filaments. The results are discussed in the context of convective transport in scrape-off layer plasmas, comprising both blob-like structures in low confinement modes and edge localized mode filaments in unstable high confinement regimes. (c) 2006 American Institute...

  12. Spectral stability of Alfven filament chains

    NARCIS (Netherlands)

    Bergmans, J.; Kuvshinov, B. N.; Lakhin, V. P.; Schep, T. J.

    2000-01-01

    The two-fluid model of nonlinear Alfven perturbations has singular solutions in the form of current-vortex filaments. We investigate analytically and numerically the spectral stability of single and double rows of filaments. Staggered and non-staggered double rows (von Karman streets) are studied. I

  13. Spectral stability of Alfven filament configurations

    NARCIS (Netherlands)

    Bergmans, J.; Kuvshinov, B. N.; Lakhin, V. P.; Schep, T. J.

    2000-01-01

    The two-fluid plasma equations that describe nonlinear Alfven perturbations have singular solutions in the form of current-vortex filaments. These filaments are analogous to point vortices in ideal hydrodynamics and geostrophic fluids. In this work the spectral (linear) stability of current-vortex f

  14. Reconstitution of the muscle thin filament from recombinant troponin components and the native thin filaments.

    Science.gov (United States)

    Matsumoto, Fumiko; Deshimaru, Shungo; Oda, Toshiro; Fujiwara, Satoru

    2010-04-15

    We have developed a technique by which muscle thin filaments are reconstituted from the recombinant troponin components and the native thin filaments. By this technique, the reconstituted troponin complex is exchanged into the native thin filaments in the presence of 20% glycerol and 0.3M KCl at pH 6.2. More than 90% of endogenous troponin complex was replaced with the recombinant troponin complex. Structural integrity and Ca(2+) sensitivity of the reconstituted thin filament prepared by this technique was confirmed by X-ray fiber diffraction measurements and the thin filament-activated myosin subfragment 1 ATPase measurements, respectively.

  15. Anaerobic Digestion of Piggery Waste

    NARCIS (Netherlands)

    Velsen, van A.F.M.

    1981-01-01

    Anaerobic digestion is a biological process by which organic matter is converted to methane and carbon dioxide by microbes in the absence of air (oxygen). In nature, anaerobic conversions occur at all places where organic material accumulates and the supply of oxygen is deficient, e.g. in marshes an

  16. Economic viability of anaerobic digestion

    Energy Technology Data Exchange (ETDEWEB)

    Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)

    1996-01-01

    The industrial application of anaerobic digestion is a relatively new, yet proven waste treatment technology. Anaerobic digestion reduces and upgrades organic waste, and is a good way to control air pollution as it reduces methane and nitrous gas emissions. For environmental and energy considerations, anaerobic digestion is a nearly perfect waste treatment process. However, its economic viability is still in question. A number of parameters - type of waste (solid or liquid), digester system, facility size, product quality and end use, environmental requirements, cost of alternative treatments (including labor), and interest rates - define the investment and operating costs of an anaerobic digestion facility. Therefore, identical facilities that treat the same amount and type of waste may, depending on location, legislation, and end product characteristics, reveal radically different costs. A good approach for evaluating the economics of anaerobic digestion is to compare it to treatment techniques such as aeration or conventional sewage treatment (for industrial wastewater), or composting and incineration (for solid organic waste). For example, the cost (per ton of waste) of in-vessel composting with biofilters is somewhat higher than that of anaerobic digestion, but the investment costs 1 1/2 to 2 times more than either composting or anaerobic digestion. Two distinct advantages of anaerobic digestion are: (1) it requires less land than either composting or incinerating, which translates into lower costs and milder environmental and community impacts (especially in densely populated areas); and (2) it produces net energy, which can be used to operate the facility or sold to nearby industries.

  17. Anaerobic digestion of solid material

    DEFF Research Database (Denmark)

    Vavilin, V.A.; Lokshina, L.Y.; Flotats, X.

    2007-01-01

    A new multidimensional (3 and 2D) anaerobic digestion model for cylindrical reactor with non-uniform influent concentration distributions was developed to study the way in which mixing intensity affects the efficiency of continuous-flow anaerobic digestion. Batch experiments reported and simulate...

  18. Particles trajectories in magnetic filaments

    Energy Technology Data Exchange (ETDEWEB)

    Bret, A. [ETSI Industriales, Universidad de Castilla-La Mancha, 13071 Ciudad Real (Spain); Instituto de Investigaciones Energéticas y Aplicaciones Industriales, Campus Universitario de Ciudad Real, 13071 Ciudad Real (Spain)

    2015-07-15

    The motion of a particle in a spatially harmonic magnetic field is a basic problem involved, for example, in the mechanism of formation of a collisionless shock. In such settings, it is generally reasoned that particles entering a Weibel generated turbulence are trapped inside it, provided their Larmor radius in the peak field is smaller than the field coherence length. The goal of this work is to put this heuristic conclusion on firm ground by studying, both analytically and numerically, such motion. A toy model is analyzed, consisting of a relativistic particle entering a region of space occupied by a spatially harmonic field. The particle penetrates the magnetic structure in a direction aligned with the magnetic filaments. Although the conclusions are not trivial, the main result is confirmed.

  19. Particles trajectories in magnetic filaments

    CERN Document Server

    Bret, Antoine

    2015-01-01

    The motion of a particle in a spatially harmonic magnetic field is a basic problem involved, for example, in the mechanism of formation of a collisionless shock. In such settings, it is generally reasoned that particles entering a Weibel generated turbulence are trapped inside it, provided their Larmor radius in the peak field is smaller than the field coherence length. The goal of this work is to put this heuristic conclusion on firm ground by studying, both analytically and numerically, such motion. A toy model is analyzed, consisting of a relativistic particle entering a region of space occupied by a spatially harmonic field. The particle penetrates the magnetic structure in a direction aligned with the magnetic filaments. Although the conclusions are not trivial, the main result is confirmed.

  20. Filamentous Growth in Eremothecium Fungi

    DEFF Research Database (Denmark)

    Oskarsson, Therese

    , this thesis deals with some of the aspects of hyphal growth, which is an important virulence factor for pathogenic fungi infecting both humans and plants. Hyphal establishment through continuous polar growth is a complex process, requiring the careful coordination of a large subset of proteins involved......-regulatory activity of AgGts1, the protein could have additional actin organizing properties. In the second and third part, this thesis addresses the use of A. gossypii and its relative E. cymbalariae as model organisms for filamentous growth. A series of assays analyzed the capability of Eremothecium genus fungi...... of molecular tools for E. cymbalariae to enable a faster and more efficient approach for genetic comparisons between Eremothecium genus fungi....

  1. Natural colorants from filamentous fungi.

    Science.gov (United States)

    Torres, Fábio Aurélio Esteves; Zaccarim, Bruna Regina; de Lencastre Novaes, Letícia Celia; Jozala, Angela Faustino; Dos Santos, Carolina Alves; Teixeira, Maria Francisca Simas; Santos-Ebinuma, Valéria Carvalho

    2016-03-01

    In the last years, there is a trend towards the replacement of synthetic colorants by natural ones, mainly due to the increase of consumer demand for natural products. The natural colorants are used to enhance the appearance of pharmaceutical products, food, and different materials, making them preferable or attractive. This review intends to provide and describe a comprehensive overview of the history of colorants, from prehistory to modern time, of their market and their applications, as well as of the most important aspects of the fermentation process to obtain natural colorants. Focus is given to colorants produced by filamentous fungal species, aiming to demonstrate the importance of these microorganisms and biocompounds, highlighting the production performance to get high yields and the aspects of conclusion that should be taken into consideration in future studies about natural colorants.

  2. Theory of Semiflexible Filaments and Networks

    Directory of Open Access Journals (Sweden)

    Fanlong Meng

    2017-02-01

    Full Text Available We briefly review the recent developments in the theory of individual semiflexible filaments, and of a crosslinked network of such filaments, both permanent and transient. Starting from the free energy of an individual semiflexible chain, models on its force-extension relation and other mechanical properties such as Euler buckling are discussed. For a permanently crosslinked network of filaments, theories on how the network responds to deformation are provided, with a focus on continuum approaches. Characteristic features of filament networks, such as nonlinear stress-strain relation, negative normal stress, tensegrity, and marginal stability are discussed. In the new area of transient filament network, where the crosslinks can be dynamically broken and re-formed, we show some recent attempts for understanding the dynamics of the crosslinks, and the related rheological properties, such as stress relaxation, yield stress and plasticity.

  3. Solar Filaments as Tracers of Subsurface Processes

    Indian Academy of Sciences (India)

    D. M. Rust

    2000-09-01

    Solar filaments are discussed in terms of two contrasting paradigms. The standard paradigm is that filaments are formed by condensation of coronal plasma into magnetic fields that are twisted or dimpled as a consequence of motions of the fields' sources in the photo-sphere. According to a new paradigm, filaments form in rising, twisted flux ropes and are a necessary intermediate stage in the transfer to interplanetary space of dynamo-generated magnetic flux. It is argued that the accumulation of magnetic helicity in filaments and their coronal surroundings leads to filament eruptions and coronal mass ejections. These ejections relieve the Sun of the flux generated by the dynamo and make way for the flux of the next cycle.

  4. Quantifying protein diffusion and capture on filaments

    CERN Document Server

    Reithmann, Emanuel; Frey, Erwin

    2015-01-01

    The functional relevance of regulating proteins is often limited to specific binding sites such as the ends of microtubules or actin-filaments. A localization of proteins on these functional sites is of great importance. We present a quantitative theory for a diffusion and capture process, where proteins diffuse on a filament and stop diffusing when reaching the filament's end. It is found that end-association after one-dimensional diffusion is the main source for tip-localization of such proteins. As a consequence, diffusion and capture is highly efficient in enhancing the reaction velocity of enzymatic reactions, where proteins and filament ends are to each other as enzyme and substrate. We show that the reaction velocity can effectively be described within a Michaelis-Menten framework. Together one-dimensional diffusion and capture beats the (three-dimensional) Smoluchowski diffusion limit for the rate of protein association to filament ends.

  5. Simultaneous RNA-seq analysis of a mixed transcriptome of rice and blast fungus interaction.

    Directory of Open Access Journals (Sweden)

    Yoshihiro Kawahara

    Full Text Available A filamentous fungus, Magnaporthe oryzae, is a causal agent of rice blast disease, which is one of the most serious diseases affecting cultivated rice, Oryza sativa. However, the molecular mechanisms underlying both rice defense and fungal attack are not yet fully understood. Extensive past studies have characterized many infection-responsive genes in the pathogen and host plant, separately. To understand the plant-pathogen interaction comprehensively, it is valuable to monitor the gene expression profiles of both interacting organisms simultaneously in the same infected plant tissue. Although the host-pathogen interaction during the initial infection stage is important for the establishment of infection, the detection of fungal gene expression in infected leaves at the stage has been difficult because very few numbers of fungal cells are present. Using the emerging RNA-Seq technique, which has a wide dynamic range for expression analyses, we analyzed the mixed transcriptome of rice and blast fungus in infected leaves at 24 hours post-inoculation, which is the point when the primary infection hyphae penetrate leaf epidermal cells. We demonstrated that our method detected the gene expression of both the host plant and pathogen simultaneously in the same infected leaf blades in natural infection conditions without any artificial treatments. The upregulation of 240 fungal transcripts encoding putative secreted proteins was observed, suggesting that these candidates of fungal effector genes may play important roles in initial infection processes. The upregulation of transcripts encoding glycosyl hydrolases, cutinases and LysM domain-containing proteins were observed in the blast fungus, whereas pathogenesis-related and phytoalexin biosynthetic genes were upregulated in rice. Furthermore, more drastic changes in expression were observed in the incompatible interactions compared with the compatible ones in both rice and blast fungus at this stage. Our

  6. Automatic Detect and Trace of Solar Filaments

    Science.gov (United States)

    Fang, Cheng; Chen, P. F.; Tang, Yu-hua; Hao, Qi; Guo, Yang

    We developed a series of methods to automatically detect and trace solar filaments in solar Hα images. The programs are able to not only recognize filaments and determine their properties, such as the position, the area and other relevant parameters, but also to trace the daily evolution of the filaments. For solar full disk Hα images, the method consists of three parts: first, preprocessing is applied to correct the original images; second, the Canny edge-detection method is used to detect the filaments; third, filament properties are recognized through the morphological operators. For each Hα filament and its barb features, we introduced the unweighted undirected graph concept and adopted Dijkstra shortest-path algorithm to recognize the filament spine; then, using polarity inversion line shift method for measuring the polarities in both sides of the filament to determine the filament axis chirality; finally, employing connected components labeling method to identify the barbs and calculating the angle between each barb and spine to indicate the barb chirality. Our algorithms are applied to the observations from varied observatories, including the Optical & Near Infrared Solar Eruption Tracer (ONSET) in Nanjing University, Mauna Loa Solar Observatory (MLSO) and Big Bear Solar Observatory (BBSO). The programs are demonstrated to be effective and efficient. We used our method to automatically process and analyze 3470 images obtained by MLSO from January 1998 to December 2009, and a butterfly diagram of filaments is obtained. It shows that the latitudinal migration of solar filaments has three trends in the Solar Cycle 23: The drift velocity was fast from 1998 to the solar maximum; after the solar maximum, it became relatively slow and after 2006, the migration became divergent, signifying the solar minimum. About 60% filaments with the latitudes larger than 50 degree migrate towards the Polar Regions with relatively high velocities, and the latitudinal migrating

  7. Unwinding motion of a twisted active region filament

    Energy Technology Data Exchange (ETDEWEB)

    Yan, X. L.; Xue, Z. K.; Kong, D. F. [Yunnan Observatories, Chinese Academy of Sciences, Kunming 650011 (China); Liu, J. H. [Department of Physics, Shijiazhuang University, Shijiazhuang 050035 (China); Xu, C. L. [Yunnan Normal University, Kunming 650092 (China)

    2014-12-10

    To better understand the structures of active region filaments and the eruption process, we study an active region filament eruption in active region NOAA 11082 in detail on 2010 June 22. Before the filament eruption, the opposite unidirectional material flows appeared in succession along the spine of the filament. The rising of the filament triggered two B-class flares at the upper part of the filament. As the bright material was injected into the filament from the sites of the flares, the filament exhibited a rapid uplift accompanying the counterclockwise rotation of the filament body. From the expansion of the filament, we can see that the filament consisted of twisted magnetic field lines. The total twist of the filament is at least 5π obtained by using a time slice method. According to the morphology change during the filament eruption, it is found that the active region filament was a twisted flux rope and its unwinding motion was like a solar tornado. We also find that there was a continuous magnetic helicity injection before and during the filament eruption. It is confirmed that magnetic helicity can be transferred from the photosphere to the filament. Using the extrapolated potential fields, the average decay index of the background magnetic fields over the filament is 0.91. Consequently, these findings imply that the mechanism of solar filament eruption could be due to the kink instability and magnetic helicity accumulation.

  8. Unwinding Motion of a Twisted Active Region Filament

    Science.gov (United States)

    Yan, X. L.; Xue, Z. K.; Liu, J. H.; Kong, D. F.; Xu, C. L.

    2014-12-01

    To better understand the structures of active region filaments and the eruption process, we study an active region filament eruption in active region NOAA 11082 in detail on 2010 June 22. Before the filament eruption, the opposite unidirectional material flows appeared in succession along the spine of the filament. The rising of the filament triggered two B-class flares at the upper part of the filament. As the bright material was injected into the filament from the sites of the flares, the filament exhibited a rapid uplift accompanying the counterclockwise rotation of the filament body. From the expansion of the filament, we can see that the filament consisted of twisted magnetic field lines. The total twist of the filament is at least 5π obtained by using a time slice method. According to the morphology change during the filament eruption, it is found that the active region filament was a twisted flux rope and its unwinding motion was like a solar tornado. We also find that there was a continuous magnetic helicity injection before and during the filament eruption. It is confirmed that magnetic helicity can be transferred from the photosphere to the filament. Using the extrapolated potential fields, the average decay index of the background magnetic fields over the filament is 0.91. Consequently, these findings imply that the mechanism of solar filament eruption could be due to the kink instability and magnetic helicity accumulation.

  9. Microbial community structure of leaf-cutter ant fungus gardens and refuse dumps.

    Directory of Open Access Journals (Sweden)

    Jarrod J Scott

    Full Text Available BACKGROUND: Leaf-cutter ants use fresh plant material to grow a mutualistic fungus that serves as the ants' primary food source. Within fungus gardens, various plant compounds are metabolized and transformed into nutrients suitable for ant consumption. This symbiotic association produces a large amount of refuse consisting primarily of partly degraded plant material. A leaf-cutter ant colony is thus divided into two spatially and chemically distinct environments that together represent a plant biomass degradation gradient. Little is known about the microbial community structure in gardens and dumps or variation between lab and field colonies. METHODOLOGY/PRINCIPAL FINDINGS: Using microbial membrane lipid analysis and a variety of community metrics, we assessed and compared the microbiota of fungus gardens and refuse dumps from both laboratory-maintained and field-collected colonies. We found that gardens contained a diverse and consistent community of microbes, dominated by Gram-negative bacteria, particularly gamma-Proteobacteria and Bacteroidetes. These findings were consistent across lab and field gardens, as well as host ant taxa. In contrast, dumps were enriched for Gram-positive and anaerobic bacteria. Broad-scale clustering analyses revealed that community relatedness between samples reflected system component (gardens/dumps rather than colony source (lab/field. At finer scales samples clustered according to colony source. CONCLUSIONS/SIGNIFICANCE: Here we report the first comparative analysis of the microbiota from leaf-cutter ant colonies. Our work reveals the presence of two distinct communities: one in the fungus garden and the other in the refuse dump. Though we find some effect of colony source on community structure, our data indicate the presence of consistently associated microbes within gardens and dumps. Substrate composition and system component appear to be the most important factor in structuring the microbial communities

  10. Filamentation of Campylobacter in broth cultures

    Directory of Open Access Journals (Sweden)

    Nacheervan M Ghaffar

    2015-06-01

    Full Text Available The transition from rod to filamentous cell morphology has been identified as a response to stressful conditions in many bacterial species and has been ascribed to confer certain survival advantages. Filamentation of Campylobacter jejuni was demonstrated to occur spontaneously on entry in to stationary phase distinguishing it from many other bacteria where a reduction in size is more common. The aim of this study was to investigate the cues that give rise to filamentation of C. jejuni and C. coli and gain insights into the process. Using minimal medium, augmentation of filamentation occurred and it was observed that this morphological change was wide spread amongst C. jejuni strains tested but was not universal in C. coli strains. Filamentation did not appear to be due to release of diffusible molecules, toxic metabolites, or be in response to oxidative stress in the medium. Separated filaments exhibited greater intracellular ATP contents (2.66 to 17.4 fg than spiral forms (0.99 to 1.7 fg and showed enhanced survival in water at 4oC and 37oC compared to spiral cells. These observations support the conclusion that the filaments are adapted to survive extra-intestinal environments. Differences in cell morphology and physiology need to be considered in the context of the design of experimental studies and the methods adopted for the isolation of campylobacters from food, clinical and environmental sources.

  11. Star forming filaments in warm dark models

    CERN Document Server

    Gao, Liang; Springel, Volker

    2014-01-01

    We performed a hydrodynamical cosmological simulation of the formation of a Milky Way-like galaxy in a warm dark matter (WDM) cosmology. Smooth and dense filaments, several co-moving mega parsec long, form generically above z 2 in this model. Atomic line cooling allows gas in the centres of these filaments to cool to the base of the cooling function, resulting in a very striking pattern of extended Lyman-limit systems (LLSs). Observations of the correlation function of LLSs might hence provide useful limits on the nature of the dark matter. We argue that the self-shielding of filaments may lead to a thermal instability resulting in star formation. We implement a sub-grid model for this, and find that filaments rather than haloes dominate star formation until z 6. Reionisation decreases the gas density in filaments, and the more usual star formation in haloes dominates below z 6, although star formation in filaments continues until z=2. Fifteen per cent of the stars of the z=0 galaxy formed in filaments. At hi...

  12. Filamentous Biopolymers on Surfaces: Atomic Force Microscopy Images Compared with Brownian Dynamics Simulation of Filament Deposition

    Science.gov (United States)

    Mücke, Norbert; Klenin, Konstantin; Kirmse, Robert; Bussiek, Malte; Herrmann, Harald; Hafner, Mathias; Langowski, Jörg

    2009-01-01

    Nanomechanical properties of filamentous biopolymers, such as the persistence length, may be determined from two-dimensional images of molecules immobilized on surfaces. For a single filament in solution, two principal adsorption scenarios are possible. Both scenarios depend primarly on the interaction strength between the filament and the support: i) For interactions in the range of the thermal energy, the filament can freely equilibrate on the surface during adsorption; ii) For interactions much stronger than the thermal energy, the filament will be captured by the surface without having equilibrated. Such a ‘trapping’ mechanism leads to more condensed filament images and hence to a smaller value for the apparent persistence length. To understand the capture mechanism in more detail we have performed Brownian dynamics simulations of relatively short filaments by taking the two extreme scenarios into account. We then compared these ‘ideal’ adsorption scenarios with observed images of immobilized vimentin intermediate filaments on different surfaces. We found a good agreement between the contours of the deposited vimentin filaments on mica (‘ideal’ trapping) and on glass (‘ideal’ equilibrated) with our simulations. Based on these data, we have developed a strategy to reliably extract the persistence length of short worm-like chain fragments or network forming filaments with unknown polymer-surface interactions. PMID:19888472

  13. Filamentous biopolymers on surfaces: atomic force microscopy images compared with Brownian dynamics simulation of filament deposition.

    Directory of Open Access Journals (Sweden)

    Norbert Mücke

    Full Text Available Nanomechanical properties of filamentous biopolymers, such as the persistence length, may be determined from two-dimensional images of molecules immobilized on surfaces. For a single filament in solution, two principal adsorption scenarios are possible. Both scenarios depend primarily on the interaction strength between the filament and the support: i For interactions in the range of the thermal energy, the filament can freely equilibrate on the surface during adsorption; ii For interactions much stronger than the thermal energy, the filament will be captured by the surface without having equilibrated. Such a 'trapping' mechanism leads to more condensed filament images and hence to a smaller value for the apparent persistence length. To understand the capture mechanism in more detail we have performed Brownian dynamics simulations of relatively short filaments by taking the two extreme scenarios into account. We then compared these 'ideal' adsorption scenarios with observed images of immobilized vimentin intermediate filaments on different surfaces. We found a good agreement between the contours of the deposited vimentin filaments on mica ('ideal' trapping and on glass ('ideal' equilibrated with our simulations. Based on these data, we have developed a strategy to reliably extract the persistence length of short worm-like chain fragments or network forming filaments with unknown polymer-surface interactions.

  14. Thermal and Chemical Evolution of Collapsing Filaments

    Energy Technology Data Exchange (ETDEWEB)

    Gray, William J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Scannapieco, Evan [Arizona State Univ., Mesa, AZ (United States). School of Earth and Space Exploration

    2013-01-15

    Intergalactic filaments form the foundation of the cosmic web that connect galaxies together, and provide an important reservoir of gas for galaxy growth and accretion. Here we present very high resolution two-dimensional simulations of the thermal and chemical evolution of such filaments, making use of a 32 species chemistry network that tracks the evolution of key molecules formed from hydrogen, oxygen, and carbon. We study the evolution of filaments over a wide range of parameters including the initial density, initial temperature, strength of the dissociating UV background, and metallicity. In low-redshift, Z ≈ 0.1Z filaments, the evolution is determined completely by the initial cooling time. If this is sufficiently short, the center of the filament always collapses to form dense, cold core containing a substantial fraction of molecules. In high-redshift, Z = 10-3Z filaments, the collapse proceeds much more slowly. This is due mostly to the lower initial temperatures, which leads to a much more modest increase in density before the atomic cooling limit is reached, making subsequent molecular cooling much less efficient. Finally, we study how the gravitational potential from a nearby dwarf galaxy affects the collapse of the filament and compare this to NGC 5253, a nearby starbusting dwarf galaxy thought to be fueled by the accretion of filament gas. In contrast to our fiducial case, a substantial density peak forms at the center of the potential. This peak evolves faster than the rest of the filament due to the increased rate at which chemical species form and cooling occur. We find that we achieve similar accretion rates as NGC 5253 but our two-dimensional simulations do not recover the formation of the giant molecular clouds that are seen in radio observations.

  15. Thermal and Chemical Evolution of Collapsing Filaments

    Energy Technology Data Exchange (ETDEWEB)

    Gray, William J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Scannapieco, Evan [Arizona State Univ., Mesa, AZ (United States). School of Earth and Space Exploration

    2013-01-15

    Intergalactic filaments form the foundation of the cosmic web that connect galaxies together, and provide an important reservoir of gas for galaxy growth and accretion. Here we present very high resolution two-dimensional simulations of the thermal and chemical evolution of such filaments, making use of a 32 species chemistry network that tracks the evolution of key molecules formed from hydrogen, oxygen, and carbon. We study the evolution of filaments over a wide range of parameters including the initial density, initial temperature, strength of the dissociating UV background, and metallicity. In low-redshift, Z ≈ 0.1Z filaments, the evolution is determined completely by the initial cooling time. If this is sufficiently short, the center of the filament always collapses to form dense, cold core containing a substantial fraction of molecules. In high-redshift, Z = 10-3Z filaments, the collapse proceeds much more slowly. This is due mostly to the lower initial temperatures, which leads to a much more modest increase in density before the atomic cooling limit is reached, making subsequent molecular cooling much less efficient. Finally, we study how the gravitational potential from a nearby dwarf galaxy affects the collapse of the filament and compare this to NGC 5253, a nearby starbusting dwarf galaxy thought to be fueled by the accretion of filament gas. In contrast to our fiducial case, a substantial density peak forms at the center of the potential. This peak evolves faster than the rest of the filament due to the increased rate at which chemical species form and cooling occur. We find that we achieve similar accretion rates as NGC 5253, but our two-dimensional simulations do not recover the formation of the giant molecular clouds that are seen in radio observations.

  16. Isolation and Cultivation of Anaerobes

    DEFF Research Database (Denmark)

    Aragao Börner, Rosa

    2016-01-01

    Anaerobic microorganisms play important roles in different biotechnological processes. Their complex metabolism and special cultivation requirements have led to less isolated representatives in comparison to their aerobic counterparts.In view of that, the isolation and cultivation of anaerobic...... microorganisms is still a promising venture, and conventional methodologies as well as considerations and modifications are presented here. An insight into new methodologies and devices as well as a discussion on future perspectives for the cultivation of anaerobes may open the prospects of the exploitation...

  17. Can We Determine the Filament Chirality by the Filament Footpoint Location or the Barb-bearing?

    CERN Document Server

    Hao, Q; Fang, C; Chen, P F; Cao, W

    2015-01-01

    We attempt to propose a method for automatically detecting the solar filament chirality and barb bearing. We first introduce the unweighted undirected graph concept and adopt the Dijkstra shortest-path algorithm to recognize the filament spine. Then, we use the polarity inversion line (PIL) shift method for measuring the polarities on both sides of the filament, and employ the connected components labeling method to identify the barbs and calculate the angle between each barb and the spine to determine the bearing of the barbs, i.e., left or right. We test the automatic detection method with H-alpha filtergrams from the Big Bear Solar Observatory (BBSO) H-alpha archive and magnetograms observed with the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). Four filaments are automatically detected and illustrated to show the results. The barbs in different parts of a filament may have opposite bearings. The filaments in the southern hemisphere (northern hemisphere) mainly have ...

  18. Open-Ended Experimentation with the Fungus Pilobolus.

    Science.gov (United States)

    Coble, Charles R.; Bland, Charles E.

    This paper describes open-ended experimentation with the fungus Pilobolus for laboratory work by high school students. The fungus structure and reproduction is described and sources of the fungus are suggested. Four areas for investigation are suggested: the effect of a diffuse light source, the effect of a point light source, the effect of light…

  19. Tailor-made CRISPR/Cas system for highly efficient targeted gene replacement in the rice blast fungus.

    Science.gov (United States)

    Arazoe, Takayuki; Miyoshi, Kennosuke; Yamato, Tohru; Ogawa, Tetsuo; Ohsato, Shuichi; Arie, Tsutomu; Kuwata, Shigeru

    2015-12-01

    CRISPR/Cas-derived RNA-guided nucleases (RGNs) that can generate DNA double-strand breaks (DSBs) at a specific sequence are widely used for targeted genome editing by induction of DSB repair in many organisms. The CRISPR/Cas system consists of two components: a single Cas9 nuclease and a single-guide RNA (sgRNA). Therefore, the system for constructing RGNs is simple and efficient, but the utilization of RGNs in filamentous fungi has not been validated. In this study, we established the CRISPR/Cas system in the model filamentous fungus, Pyricularia oryzae, using Cas9 that was codon-optimized for filamentous fungi, and the endogenous RNA polymerase (RNAP) III U6 promoter and a RNAP II fungal promoter for the expression of the sgRNA. We further demonstrated that RGNs could recognize the desired sequences and edit endogenous genes through homologous recombination-mediated targeted gene replacement with high efficiency. Our system will open the way for the development of various CRISPR/Cas-based applications in filamentous fungi.

  20. Tunnel ionization, population trapping, filamentation and applications

    Science.gov (United States)

    Leang Chin, See; Xu, Huailiang

    2016-11-01

    The advances in femtosecond Ti-sapphire laser technology have led to the discovery of a profusion of new physics. This review starts with a brief historical account of the experimental realization of tunnel ionization, followed by high harmonic generation and the prediction of attosecond pulses. Then, the unique phenomenon of dynamic population trapping during the ionization of atoms and molecules in intense laser fields is introduced. One of the consequences of population trapping in the highly excited states is the neutral dissociation into simple molecular fragments which fluoresce. Such fluorescence could be amplified in femtosecond laser filamentation in gases. The experimental observations of filament-induced fluorescence and lasing in the atmosphere and combustion flames are given. Excitation of molecular rotational wave packets (molecular alignment) and their relaxation and revival in a gas filament are described. Furthermore, filament-induced condensation and precipitation inside a cloud chamber is explained. Lastly, a summary and future outlook is given.

  1. Interaction and merging of vortex filaments

    Science.gov (United States)

    Liu, C. H.; Weston, R. P.; Ishii, K.; Ting, L.; Visintainer, J. A.

    1988-01-01

    The asymptotic solutions of Navier-Stokes equations for vortex filaments of finite strength with small effective vortical cores are summarized with special emphasis placed on the physical meaning and the practical limit to the applicability of the asymptotic solution. Finite-difference solutions of Navier-Stokes equations for the marging of the filament(s) are described with a focus on the development of the approximate boundary conditions for the computational domain. An efficiency study employing a model problem is used to assess the advantages of the present approximate boundary condition method over previously used techniques. Applications of the present method are presented for the motion and decay of a 3:1 elliptic vortex ring, and for the merging process of a pair of coaxial vortex rings. A numerical procedure for the problem of local merging of vortex filaments, which requires the asymptotic analysis as well as the numerical Navier-Stokes solver, is also presented.

  2. Organizing Filament of Small Amplitude Scroll Waves

    Institute of Scientific and Technical Information of China (English)

    ZHOU TianShou; ZHANG SuoChun

    2001-01-01

    We theoretically analyze the organizing filament of small amplitude scroll waves in general excitable media by perturbation method and explicitly give the expressions of coefficients in Keener theory. In particular for the excitable media with equal diffusion, we obtain a close system for the motion of the filament. With an example of the Oregonator model, our results are in good agreement with those simulated by Winfree.``

  3. Anaerobic Biodegradation of Detergent Surfactants

    OpenAIRE

    Erich Jelen; Ute Merrettig-Bruns

    2009-01-01

    Detergent surfactantscan be found in wastewater in relevant concentrations. Most of them are known as ready degradable under aerobic conditions, as required by European legislation. Far fewer surfactants have been tested so far for biodegradability under anaerobic conditions. The natural environment is predominantly aerobic, but there are some environmental compartments such as river sediments, sub-surface soil layer and anaerobic sludge digesters of wastewater treatment plants which have str...

  4. On the nature of star-forming filaments: II. Sub-filaments and velocities

    CERN Document Server

    Smith, Rowan J; Klessen, Ralf S; Fuller, Gary A

    2015-01-01

    We show that hydrodynamic turbulent cloud simulations naturally produce large filaments made up of a network of smaller and coherent sub-filaments. Such simulations resemble observations of filaments and fibres in nearby molecular clouds. The sub-filaments are dynamical features formed at the stagnation points of the turbulent velocity field where shocks dissipate the turbulent energy. They are a ubiquitous feature of the simulated clouds, which appear from the beginning of the simulation and are not formed by gradual fragmentation of larger filaments. Most of the sub-filaments are gravitationally sub-critical and do not fragment into cores, however, there is also a significant fraction of supercritical sub-filaments which break up into star-forming cores. The sub-filaments are coherent along their length, and the residual velocities along their spine show that they are subsonically contracting without any ordered rotation on scales of ~0.1 pc. Accretion flows along the sub-filaments can feed material into st...

  5. Actin filament attachments for sustained motility in vitro are maintained by filament bundling.

    Directory of Open Access Journals (Sweden)

    Xiaohua Hu

    Full Text Available We reconstructed cellular motility in vitro from individual proteins to investigate how actin filaments are organized at the leading edge. Using total internal reflection fluorescence microscopy of actin filaments, we tested how profilin, Arp2/3, and capping protein (CP function together to propel thin glass nanofibers or beads coated with N-WASP WCA domains. Thin nanofibers produced wide comet tails that showed more structural variation in actin filament organization than did bead substrates. During sustained motility, physiological concentrations of Mg(2+ generated actin filament bundles that processively attached to the nanofiber. Reduction of total Mg(2+ abolished particle motility and actin attachment to the particle surface without affecting actin polymerization, Arp2/3 nucleation, or filament capping. Analysis of similar motility of microspheres showed that loss of filament bundling did not affect actin shell formation or symmetry breaking but eliminated sustained attachments between the comet tail and the particle surface. Addition of Mg(2+, Lys-Lys(2+, or fascin restored both comet tail attachment and sustained particle motility in low Mg(2+ buffers. TIRF microscopic analysis of filaments captured by WCA-coated beads in the absence of Arp2/3, profilin, and CP showed that filament bundling by polycation or fascin addition increased barbed end capture by WCA domains. We propose a model in which CP directs barbed ends toward the leading edge and polycation-induced filament bundling sustains processive barbed end attachment to the leading edge.

  6. Can we determine the filament chirality by the filament footpoint location or the barb-bearing?

    Science.gov (United States)

    Hao, Qi; Guo, Yang; Fang, Cheng; Chen, Peng-Fei; Cao, Wen-Da

    2016-01-01

    We attempt to propose a method for automatically detecting the solar filament chirality and barb bearing. We first introduce the concept of an unweighted undirected graph and adopt the Dijkstra shortest path algorithm to recognize the filament spine. Then, we use the polarity inversion line (PIL) shift method for measuring the polarities on both sides of the filament, and employ the connected components labeling method to identify the barbs and calculate the angle between each barb and the spine to determine the bearing of the barbs, i.e., left or right. We test the automatic detection method with Hα filtergrams from the Big Bear Solar Observatory (BBSO) Hα archive and magnetograms observed with the Helioseismic and Magnetic Imager (HMI) on board the Solar Dynamics Observatory (SDO). Four filaments are automatically detected and illustrated to show the results. The barbs in different parts of a filament may have opposite bearings. The filaments in the southern hemisphere (northern hemisphere) mainly have left-bearing (right-bearing) barbs and positive (negative) magnetic helicity, respectively. The tested results demonstrate that our method is efficient and effective in detecting the bearing of filament barbs. It is demonstrated that the conventionally believed one-to-one correspondence between filament chirality and barb bearing is not valid. The correct detection of the filament axis chirality should be done by combining both imaging morphology and magnetic field observations.

  7. Filaments in the Lupus molecular clouds

    Science.gov (United States)

    Benedettini, M.; Schisano, E.; Pezzuto, S.; Elia, D.; André, P.; Könyves, V.; Schneider, N.; Tremblin, P.; Arzoumanian, D.; di Giorgio, A. M.; Di Francesco, J.; Hill, T.; Molinari, S.; Motte, F.; Nguyen-Luong, Q.; Palmeirim, P.; Rivera-Ingraham, A.; Roy, A.; Rygl, K. L. J.; Spinoglio, L.; Ward-Thompson, D.; White, G. J.

    2015-10-01

    We have studied the filaments extracted from the column density maps of the nearby Lupus 1, 3, and 4 molecular clouds, derived from photometric maps observed with the Herschel satellite. Filaments in the Lupus clouds have quite low column densities, with a median value of ˜1.5 × 1021 cm-2 and most have masses per unit length lower than the maximum critical value for radial gravitational collapse. Indeed, no evidence of filament contraction has been seen in the gas kinematics. We find that some filaments, that on average are thermally subcritical, contain dense cores that may eventually form stars. This is an indication that in the low column density regime, the critical condition for the formation of stars may be reached only locally and this condition is not a global property of the filament. Finally, in Lupus we find multiple observational evidences of the key role that the magnetic field plays in forming filaments, and determining their confinement and dynamical evolution.

  8. Filaments in the Lupus molecular clouds

    CERN Document Server

    Benedettini, M; Pezzuto, S; Elia, D; André, P; Könyves, V; Schneider, N; Tremblin, P; Arzoumanian, D; di Giorgio, A M; Di Francesco, J; Hill, T; Molinari, S; Motte, F; Nguyen-Luong, Q; Palmeirim, P; Rivera-Ingraham, A; Roy, A; Rygl, K L J; Spinoglio, L; Ward-Thompson, D; White, G J

    2015-01-01

    We have studied the filaments extracted from the column density maps of the nearby Lupus 1, 3, and 4 molecular clouds, derived from photometric maps observed with the Herschel satellite. Filaments in the Lupus clouds have quite low column densities, with a median value of $\\sim$1.5$\\times$10$^{21}$ cm$^{-2}$ and most have masses per unit length lower than the maximum critical value for radial gravitational collapse. Indeed, no evidence of filament contraction has been seen in the gas kinematics. We find that some filaments, that on average are thermally subcritical, contain dense cores that may eventually form stars. This is an indication that in the low column density regime, the critical condition for the formation of stars may be reached only locally and this condition is not a global property of the filament. Finally, in Lupus we find multiple observational evidences of the key role that the magnetic field plays in forming filaments, and determining their confinement and dynamical evolution.

  9. Filaments in Simulations of Molecular Cloud Formation

    CERN Document Server

    Gomez, Gilberto C

    2013-01-01

    We report on the filaments that develop self-consistently in a new numerical simulation of cloud formation by colliding flows. As in previous studies, the forming cloud begins to undergo gravitational collapse because it rapidly acquires a mass much larger than the average Jeans mass. Thus, the collapse is hierarchical in nature, proceeding along its shortest dimension first. This naturally produces filaments in cloud, and clumps within the filaments. The filaments are not in equilibrium at any time, but instead are long-lived flow features, through which the gas flows from the cloud to the clumps. The filaments are long-lived because they accrete from their environment while simultaneously accreting onto the clumps within them; they are essentially the locus where the flow changes from accreting in two dimensions to accreting in one dimension. Moreover, the clumps also exhibit a hierarchical nature: the gas in a filament flows onto a main, central clump, but other, smaller-scale clumps form along the infalli...

  10. Solanapyrone analogues from a Hawaiian fungicolous fungus

    Science.gov (United States)

    Four new solanayrone analogues (solanapyrones J-M; 1-4) have been isolated from an unidentified fungicolous fungus collected in Hawaii. The structures and relative configurations of these compounds were determined by analysis of ID NMR, 2D NMR, and MS data. Solanapyrone J(1) showed antifungal acti...

  11. Death from Fungus in the Soil

    Centers for Disease Control (CDC) Podcasts

    2012-12-17

    Dr. Shira Shafir, Assistant Professor of Epidemiology at the UCLA Fielding School of Public Health, discusses her study about fungus found in soil.  Created: 12/17/2012 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 12/18/2012.

  12. Spread of Rare Fungus from Vancouver Island

    Centers for Disease Control (CDC) Podcasts

    2006-12-20

    Cryptococcus gattii, a rare fungus normally found in the tropics, has infected people and animals on Vancouver Island, Canada. Dr. David Warnock, Director, Division of Foodborne, Bacterial, and Mycotic Diseases, CDC, discusses public health concerns about further spread of this organism.  Created: 12/20/2006 by Emerging Infectious Diseases.   Date Released: 12/29/2006.

  13. Microbial populations of an upflow anaerobic sludge blanket reactor treating wastewater from a gelatin industry.

    Science.gov (United States)

    Vieira, A M; Bergamasco, R; Gimenes, M L; Nakamura, C V; Dias Filho, B P

    2001-12-01

    The microbial populations of an upflow anaerobic sludge blanket reactor, used for treating wastewater from the gelatin industry, were studied by microbiological methods and phase-contrast and electron microscopy. Microscopy examination of the sludge showed a complex mixture of various rod-shaped and coccoid bacterial pluslong filaments and verymobile curved rods. In addition free-living anaerobic ciliates and flagellates were also observed. The trophic group population observed in decreasing order of dominance were hydrolytic and acetogenic at 10(6) and sulfate reducing and methanogenic at 10(5). The rate of methane production in anaerobic granular sludge cultivated in growth medium supplement with formate pressurized with H2:CO2 showed a significant increase in methane yield compared with theseed culture containingthe same substrate and atmosphere of N2:CO2. Similar rates of methane production were observed when the growth medium was supplemented with acetate pressurized either with H2:CO2 or N2:CO2. The number of total anaerobic bacteria at 10(7), fecal coliforms and total coliforms at 10(6), and fecal streptococci at 10(3) is based on colony counts on solid media. The four prevalent species of facultative anaerobic gram-negative bacteria that belong to the family of Enterobacteriaceae were identified as Escherichia coli, Esherichia fergusonii, Klebsiella oxytoca, and Citrobacter freundii. The species Aeromonas hydrophila, Aeromonas veronii, Acinetobacter iwoffi and Stenotrophomonas maltophila were the most frequently isolated glucose fermenting and nonfermenting gram-negative bacilli.

  14. Potential fields of merging and splitting filaments in air

    Institute of Scientific and Technical Information of China (English)

    Ma Yuan-Yuan; Lu Xin; Xi Ting-Ting; Hao Zuo-Qiang; Gong Qi-Huang; Zhang Jie

    2007-01-01

    Two interacting light filaments with different initial phases propagating in air are investigated numerically by using a ray tracing method. The evolution of the rays of a filament is governed by a potential field. During propagation, the two potential wells of the two filaments can merge into one or repel each other, depending on the initial phase difference between the two filaments. The study provides a simple description of the interacting filaments.

  15. Aspergillus mulundensis sp. nov., a new species for the fungus producing the antifungal echinocandin lipopeptides, mulundocandins.

    Science.gov (United States)

    Bills, Gerald F; Yue, Qun; Chen, Li; Li, Yan; An, Zhiqiang; Frisvad, Jens C

    2016-03-01

    The invalidly published name Aspergillus sydowii var. mulundensis was proposed for a strain of Aspergillus that produced new echinocandin metabolites designated as the mulundocadins. Reinvestigation of this strain (Y-30462=DSMZ 5745) using phylogenetic, morphological, and metabolic data indicated that it is a distinct and novel species of Aspergillus sect. Nidulantes. The taxonomic novelty, Aspergillus mulundensis, is introduced for this historically important echinocandin-producing strain. The closely related A. nidulans FGSC A4 has one of the most extensively characterized secondary metabolomes of any filamentous fungus. Comparison of the full-genome sequences of DSMZ 5745 and FGSC A4 indicated that the two strains share 33 secondary metabolite biosynthetic gene clusters. These shared gene clusters represent ~45% of the total secondary metabolome of each strain, thus indicating a high level intraspecific divergence in terms of secondary metabolism.

  16. Staurosporine Induces Filamentation in the Human Fungal Pathogen Candida albicans via Signaling through Cyr1 and Protein Kinase A

    Science.gov (United States)

    Xie, Jinglin L.; O’Meara, Teresa R.; Polvi, Elizabeth J.; Robbins, Nicole

    2017-01-01

    infections. Treatment of these infections is extremely difficult, as fungi are closely related to humans, and there are limited drugs that kill the fungus without host toxicity. The capacity of C. albicans to transition between yeast and filamentous forms is a key virulence trait. Thus, understanding the genetic pathways that regulate morphogenesis could provide novel therapeutic targets to treat C. albicans infections. Here, we establish the small molecule staurosporine as an inducer of filamentous growth. We unveil distinct regulatory circuitry required for staurosporine-induced filamentation that appears to be unique to this filament-inducing cue. Thus, this work highlights the fact that small molecules, such as staurosporine, can improve our understanding of the pathways required for key virulence programs, which may lead to the development of novel therapeutics. PMID:28261668

  17. Engineering of the redox imbalance of Fusarium oxysporum enables anaerobic growth on xylose

    DEFF Research Database (Denmark)

    Panagiotou, Gianni; Christakopoulos, Paul; Grotkjær, Thomas

    2006-01-01

    Dissimilatory nitrate reduction metabolism, of the natural xylose-fermenting fungus Fusarium oxysporum, was used as a strategy to achieve anaerobic growth and ethanol production from xylose. Beneficial alterations of the redox fluxes and thereby of the xylose metabolism were obtained by taking...... state. F. oxysporum grew anaerobically on [1-C-13] labelled glucose and unlabelled xylose in chemostat cultivation with nitrate as nitrogen source. The use of labelled substrate allowed the precise determination of the glucose and xylose contribution to the carbon fluxes in the central metabolism...... of nitrate with ammonium limited the growth significantly (0.15 g L-1 biomass). Using nitrate, the maximum acetate yield was 0.21 moles per mole of xylose and no xylitol excretion was observed. Furthermore, the network structure in the central carbon metabolism of F. oxysporum was characterized in steady...

  18. PDGF induces reorganization of vimentin filaments.

    Science.gov (United States)

    Valgeirsdóttir, S; Claesson-Welsh, L; Bongcam-Rudloff, E; Hellman, U; Westermark, B; Heldin, C H

    1998-07-30

    In this study we demonstrate that stimulation with platelet-derived growth factor (PDGF) leads to a marked reorganization of the vimentin filaments in porcine aortic endothelial (PAE) cells ectopically expressing the PDGF beta-receptor. Within 20 minutes after stimulation, the well-spread fine fibrillar vimentin was reorganized as the filaments aggregated into a dense coil around the nucleus. The solubility of vimentin upon Nonidet-P40-extraction of cells decreased considerably after PDGF stimulation, indicating that PDGF caused a redistribution of vimentin to a less soluble compartment. In addition, an increased tyrosine phosphorylation of vimentin was observed. The redistribution of vimentin was not a direct consequence of its tyrosine phosphorylation, since treatment of cells with an inhibitor for the cytoplasmic tyrosine kinase Src, attenuated phosphorylation but not redistribution of vimentin. These changes in the distribution of vimentin occurred in conjunction with reorganization of actin filaments. In PAE cells expressing a Y740/751F mutant receptor that is unable to bind and activate phosphatidylinositol 3'-kinase (PI3-kinase), the distribution of vimentin was virtually unaffected by PDGF stimulation. Thus, PI3-kinase is important for vimentin reorganization, in addition to its previously demonstrated role in actin reorganization. The small GTPase Rac has previously been shown to be involved downstream of PI3-kinase in the reorganization of actin filaments. In PAE cells overexpressing dominant negative Rac1 (N17Rac1), no change in the fine fibrillar vimentin network was seen after PDGF-BB stimulation, whereas in PAE cells overexpressing constitutively active Rac1 (V12Rac1), there was a dramatic change in vimentin filament organization independent of PDGF stimulation. These data indicate that PDGF causes a reorganization of microfilaments as well as intermediate filaments in its target cells and suggest an important role for Rac downstream of PI3-kinase in

  19. The cell end marker Tea4 regulates morphogenesis and pathogenicity in the basidiomycete fungus Ustilago maydis.

    Science.gov (United States)

    Valinluck, Michael; Woraratanadharm, Tad; Lu, Ching-yu; Quintanilla, Rene H; Banuett, Flora

    2014-05-01

    Positional cues localized to distinct cell domains are critical for the generation of cell polarity and cell morphogenesis. These cues lead to assembly of protein complexes that organize the cytoskeleton resulting in delivery of vesicles to sites of polarized growth. Tea4, an SH3 domain protein, was first identified in fission yeast, and is a critical determinant of the axis of polarized growth, a role conserved among ascomycete fungi. Ustilago maydis is a badiomycete fungus that exhibits a yeast-like form that is nonpathogenic and a filamentous form that is pathogenic on maize and teozintle. We are interested in understanding how positional cues contribute to generation and maintenance of these two forms, and their role in pathogenicity. We identified a homologue of fission yeast tea4 in a genetic screen for mutants with altered colony and cell morphology and present here analysis of Tea4 for the first time in a basidiomycete fungus. We demonstrate that Tea4 is an important positional marker for polarized growth and septum location in both forms. We uncover roles for Tea4 in maintenance of cell and neck width, cell separation, and cell wall deposition in the yeast-like form, and in growth rate, formation of retraction septa, growth reversal, and inhibition of budding in the filamentous form. We show that Tea4::GFP localizes to sites of polarized or potential polarized growth in both forms, as observed in ascomycete fungi. We demonstrate an essential role of Tea4 in pathogencity in the absence of cell fusion. Basidiomycete and ascomycete Tea4 homologues share SH3 and Glc7 domains. Tea4 in basidiomycetes has additional domains, which has led us to hypothesize that Tea4 has novel functions in this group of fungi.

  20. Filament Activation in Response to Magnetic Flux Emergence and Cancellation in Filament Channels

    CERN Document Server

    Li, Ting; Ji, Haisheng

    2015-01-01

    We make a comparative analysis for two filaments that showed quite different activation in response to the flux emergence within the filament channels. The observations from the Solar Dynamics Observatory (SDO) and Global Oscillation Network Group (GONG) are carried out to analyze the two filaments on 2013 August 17-20 and September 29. The first event showed that the main body of the filament was separated into two parts when an active region (AR) emerged with a maximum magnetic flux of about 6.4*10^21 Mx underlying the filament. The close neighborhood and common direction of the bright threads in the filament and the open AR fan loops suggest similar magnetic connectivity of these two flux systems. The equilibrium of the filament was not destroyed within 3 days after the start of the emergence of the AR. To our knowledge, similar observations have never been reported before. In the second event, the emerging flux occurred nearby a barb of the filament with a maximum magnetic flux of 4.2*10^20 Mx, about one ...

  1. FgFlbD regulates hyphal differentiation required for sexual and asexual reproduction in the ascomycete fungus Fusarium graminearum.

    Science.gov (United States)

    Son, Hokyoung; Kim, Myung-Gu; Chae, Suhn-Kee; Lee, Yin-Won

    2014-11-01

    Fusarium graminearum is a filamentous fungal plant pathogen that infects major cereal crops. The fungus produces both sexual and asexual spores in order to endure unfavorable environmental conditions and increase their numbers and distribution across plants. In a model filamentous fungus, Aspergillus nidulans, early induction of conidiogenesis is orchestrated by the fluffy genes. The objectives of this study were to characterize fluffy gene homologs involved in conidiogenesis and their mechanism of action in F. graminearum. We characterized five fluffy gene homologs in F. graminearum and found that FlbD is the only conserved regulator for conidiogenesis in A. nidulans and F. graminearum. Deletion of fgflbD prevented hyphal differentiation and the formation of perithecia. Successful interspecies complementation using A. nidulans flbD demonstrated that the molecular mechanisms responsible for FlbD functions are conserved in F. graminearum. Moreover, abaA-wetA pathway is positively regulated by FgFlbD during conidiogenesis in F. graminearum. Deleting fgflbD abolished morphological effects of abaA overexpression, which suggests that additional factors for FgFlbD or an AbaA-independent pathway for conidiogenesis are required for F. graminearum conidiation. Importantly, this study led to the construction of a genetic pathway of F. graminearum conidiogenesis and provides new insights into the genetics of conidiogenesis in fungi.

  2. Ant-fungus species combinations engineer physiological activity of fungus gardens.

    Science.gov (United States)

    Seal, J N; Schiøtt, M; Mueller, U G

    2014-07-15

    Fungus-gardening insects are among the most complex organisms because of their extensive co-evolutionary histories with obligate fungal symbionts and other microbes. Some fungus-gardening insect lineages share fungal symbionts with other members of their lineage and thus exhibit diffuse co-evolutionary relationships, while others exhibit little or no symbiont sharing, resulting in host-fungus fidelity. The mechanisms that maintain this symbiont fidelity are currently unknown. Prior work suggested that derived leaf-cutting ants in the genus Atta interact synergistically with leaf-cutter fungi (Attamyces) by exhibiting higher fungal growth rates and enzymatic activities than when growing a fungus from the sister-clade to Attamyces (so-called 'Trachymyces'), grown primarily by the non-leaf cutting Trachymyrmex ants that form, correspondingly, the sister-clade to leaf-cutting ants. To elucidate the enzymatic bases of host-fungus specialization in leaf-cutting ants, we conducted a reciprocal fungus-switch experiment between the ant Atta texana and the ant Trachymyrmex arizonensis and report measured enzymatic activities of switched and sham-switched fungus gardens to digest starch, pectin, xylan, cellulose and casein. Gardens exhibited higher amylase and pectinase activities when A. texana ants cultivated Attamyces compared with Trachymyces fungi, consistent with enzymatic specialization. In contrast, gardens showed comparable amylase and pectinase activities when T. arizonensis cultivated either fungal species. Although gardens of leaf-cutting ants are not known to be significant metabolizers of cellulose, T. arizonensis were able to maintain gardens with significant cellulase activity when growing either fungal species. In contrast to carbohydrate metabolism, protease activity was significantly higher in Attamyces than in Trachymyces, regardless of the ant host. Activity of some enzymes employed by this symbiosis therefore arises from complex interactions between the

  3. The in situ physiology of "Nostocoida limicola" II, a filamentous bacterial morphotype in bulking activated sludge, using fluorescence in situ hybridization and microautoradiography.

    Science.gov (United States)

    Seviour, E M; Eales, K; Izzard, L; Beer, M; Carr, E L; Seviour, R J

    2006-01-01

    The in situ physiology of the actinobacterial bulking and foaming filamentous bacterium "Nostocoida limicola" II was studied by fluorescence in situ hybridization/microautoradiography. Substrate assimilation patterns of pure cultures of this bacterium were different to those seen in activated sludge biomass samples. There was no evidence to suggest that "N. limicola" II preferred hydrophobic substrates, but evidence was produced to support the view that it is metabolically active under anaerobic conditions in activated sludge.

  4. Peroxide accumulation and cell death in filamentous fungi induced by contact with a contestant.

    Science.gov (United States)

    Silar, Philippe

    2005-02-01

    Podospora anserina and Coprinopsis cinerea (syn. Coprinus cinereus) are endowed with a defence system able to differentiate self vs. non-self and involving the generation of peroxide. Indeed, they produce peroxide when confronted with a filamentous fungus, only in non-self confrontations. Both species are not able to recognize yeasts and show a differential response to bacteria. The accumulation of peroxides in the ascomycete Podospora anserina requires an NADPH oxidase and a MAP kinase cascade, previously shown to be involved in fruit body formation, cell differentiation and cell degeneration. Confrontation is accompanied by the death of the contestant hyphae only in specific combinations of species. As in animals and plants, data suggest that peroxide is likely involved in signalling rather than playing a direct toxic role. Fungi display more complex behaviours than generally acknowledged, i.e. they are able to recognize potential contestants and built up defence reactions involving evolutionary conserved enzymes.

  5. The use of secondary metabolite profiling in chemotaxonomy of filamentous fungi

    DEFF Research Database (Denmark)

    Frisvad, Jens Christian; Andersen, Birgitte; Thrane, Ulf

    2008-01-01

    , protozoa, and animals are less efficient producers. Therefore, secondary metabolites have mostly been used in plant and fungal taxonomy, whereas chemotaxonomy has been neglected in bacteriology. Lichen chemotaxonomy has been based on few biosynthetic families (chemosyndromes), whereas filamentous fungi......A secondary metabolite is a chemical compound produced by a limited number of fungal species in a genus, an order, or even phylum. A profile of secondary metabolites consists of all the different compounds a fungus can produce on a given substratum and includes toxins, antibiotics and other outward......-directed compounds. Chemotaxonomy is traditionally restricted to comprise fatty acids, proteins, carbohydrates, or secondary metabolites, but has sometimes been defined so broadly that it also includes DNA sequences. It is not yet possible to use secondary metabolites in phylogeny, because of the inconsistent...

  6. Drops moving along and across a filament

    Science.gov (United States)

    Sahu, Rakesh P.; Sinha-Ray, Suman; Yarin, Alexander; Pourdeyhimi, Behnam

    2013-11-01

    The present work is devoted to the experimental study of oil drop motion both along and across a filament due to the air jet blowing. In case of drop moving along the filament, phenomena such as drop stick-slip motion, shape oscillations, shedding of a tail along the filament, the tail capillary instability and drop recoil motion were observed which were rationalized in the framework of simplified models. Experiments with cross-flow of the surrounding gas relative to the filament with an oil drop on it were conducted, with air velocity in the range of 7.23 to 22.7 m s-1. The Weber number varied from 2 to 40 and the Ohnesorge number varied from 0.07 to 0.8. The lower and upper critical Weber numbers were introduced to distinguish between the beginning of the drop blowing off the filament and the onset of the bag-stamen breakup. The range of the Weber number between these two critical values is filled with three types of vibrational breakup: V1 (a balloon-like drop being blown off), V2 (a drop on a single stamen being blown off), and V3 (a drop on a double stamen being blown off). The Weber number/Ohnesorge number plane was delineated into domains of different breakup regimes. The work is supported by the Nonwovens Cooperative Research Center (NCRC).

  7. The hydrodynamic stability of gaseous cosmic filaments

    CERN Document Server

    Birnboim, Yuval; Zinger, Elad

    2016-01-01

    Virial shocks at edges of cosmic-web structures are a clear prediction of standard structure formation theories. We derive a criterion for the stability of the post-shock gas and of the virial shock itself in spherical, filamentary and planar infall geometries. When gas cooling is important, we find that shocks become unstable, and gas flows uninterrupted towards the center of the respective halo, filament or sheet. For filaments, we impose this criterion on self-similar infall solutions. We find that instability is expected for filament masses between $10^{11}-10^{13}M_\\odot Mpc^{-1}.$ Using a simplified toy model, we then show that these filaments will likely feed halos with $10^{10}M_{\\odot}\\lesssim M_{halo}\\lesssim 10^{13}M_{\\odot}$ at redshift $z=3$, as well as $10^{12}M_{\\odot}\\lesssim M_{halo}\\lesssim 10^{15}M_{\\odot}$ at $z=0$. The instability will affect the survivability of the filaments as they penetrate gaseous halos in a non-trivial way. Additionally, smaller halos accreting onto non-stable filam...

  8. Occurrence of fungi in combs of fungus-growing termites (Isoptera: Termitidae, Macrotermitinae).

    Science.gov (United States)

    Guedegbe, Herbert J; Miambi, Edouard; Pando, Anne; Roman, Jocelyne; Houngnandan, Pascal; Rouland-Lefevre, Corinne

    2009-10-01

    Fungus-growing termites cultivate their mutualistic basidiomycete Termitomyces species on a substrate called a fungal comb. Here, the Suicide Polymerase Endonuclease Restriction (SuPER) method was adapted for the first time to a fungal study to determine the entire fungal community of fungal combs and to test whether fungi other than the symbiotic cultivar interact with termite hosts. Our molecular analyses show that although active combs are dominated by Termitomyces fungi isolated with direct Polymerase Endonuclease Restriction - Denaturing Gradient Gel Electrophoresis (PCR-DGGE), they can also harbor some filamentous fungi and yeasts only revealed by SuPER PCR-DGGE. This is the first molecular evidence of the presence of non-Termitomyces species in active combs. However, because there is no evidence for a species-specific relationship between these fungi and termites, they are mere transient guests with no specialization in the symbiosis. It is however surprising to notice that termite-associated Xylaria strains were not isolated from active combs even though they are frequently retrieved when nests are abandoned by termites. This finding highlights the implication of fungus-growing termites in the regulation of fungi occurring within the combs and also suggests that they might not have any particular evolutionary-based association with Xylaria species.

  9. Green Chemistry Approach for the Synthesis of Gold Nanoparticles Using the Fungus Alternaria sp.

    Science.gov (United States)

    Dhanasekar, Naresh Niranjan; Rahul, Ganga Ravindran; Narayanan, Kannan Badri; Raman, Gurusamy; Sakthivel, Natarajan

    2015-07-01

    The synthesis of gold nanoparticles has gained tremendous attention owing to their immense applications in the field of biomedical sciences. Although several chemical procedures are used for the synthesis of nanoparticles, the release of toxic and hazardous by-products restricts their use in biomedical applications. In the present investigation, gold nanoparticles were synthesized biologically using the culture filtrate of the filamentous fungus Alternaria sp. The culture filtrate of the fungus was exposed to three different concentrations of chloroaurate ions. In all cases, the gold ions were reduced to Au(0), leading to the formation of stable gold nanoparticles of variable sizes and shapes. UV-Vis spectroscopy analysis confirmed the formation of nanoparticles by reduction of Au(3+) to Au(0). TEM analysis revealed the presence of spherical, rod, square, pentagonal, and hexagonal morphologies for 1 mM chloroaurate solution. However, quasi-spherical and spherical nanoparticles/heart-like morphologies with size range of about 7-13 and 15-18 nm were observed for lower molar concentrations of 0.3 and 0.5 mM gold chloride solution, respectively. The XRD spectrum revealed the face-centered cubic crystals of synthesized gold nanoparticles. FT-IR spectroscopy analysis confirmed the presence of aromatic primary amines, and the additional SPR bands at 290 and 230 nm further suggested that the presence of amino acids such as tryptophan/tyrosine or phenylalanine acts as the capping agent on the synthesized mycogenic gold nanoparticles.

  10. Comparative analysis of mixing distribution in aerobic stirred bioreactor for simulated yeasts and fungus broths.

    Science.gov (United States)

    Cascaval, Dan; Galaction, Anca-Irina; Turnea, Marius

    2007-01-01

    The study on mixing distribution for an aerobic stirred bioreactor and simulated (solutions of carboxymethylcellulose sodium salt), yeasts (S. cerevisiae) and fungus (P. chrysogenum pellets and free mycelia) broths indicated the significant variation of mixing time on the bioreactor height. The experiments suggested the possibility to reach a uniform mixing in whole bulk of the real broths for a certain value of rotation speed or biomass concentration domain. For S. cerevisiae broths the optimum rotation speed increased to 500 rpm with the biomass accumulation from 40 to 150 g/l d.w. Irrespective of their morphology, for fungus cultures the existence of optimum rotation speed (500 rpm) has been recorded only for biomass concentration below 24 g/l d.w. The influence of aeration rate depends on the apparent viscosity/biomass concentration and on the impellers and sparger positions. By increasing the apparent viscosity for simulated broths, or biomass amount for real broths, the shape of the curves describing the mixing time variation is significantly changed for all the considered positions. The intensification of the aeration induced the increase of mixing time, which reached a maximum value, decreasing then, due to the flooding phenomena. This variation became more pronounced at higher viscosities for simulated broths, at higher yeasts concentration, and at lower pellets or filamentous fungus concentration, respectively. By means of the experimental data and using MATLAB software, some mathematical correlations for mixing time have been proposed for each broth and considered position inside the bioreactor. These equations offer a good agreement with the experiment, the maximum deviation being +/-7.3% for S. cerevisiae broths.

  11. Free-Space Nonlinear Beam Combining Towards Filamentation

    CERN Document Server

    Rostami, Shermineh; Kepler, Daniel; Baudelet, Matthieu; Litchinitser, Natalia M; Richardson, Martin

    2016-01-01

    Multi-filamentation opens new degrees of freedom for manipulating electromagnetic waves in air. However, without control, multiple filament interactions, including attraction, repulsion or fusion often result in formation of complex disordered filament distributions. Moreover, high power beams conventionally used in multi-filament formation experiments often cause significant surface damage. The growing number of applications for laser filaments requires fine control of their formation and propagation. We demonstrate, experimentally and theoretically, that the attraction and fusion of ultrashort beams with initial powers below the critical value enable the eventual formation of a filament downstream. Filament formation is delayed to a predetermined distance in space, avoiding optical damage to external beam optics while still enabling robust filaments with controllable properties as if formed from a single high power beam. This paradigm introduces new opportunities for filament engineering eliminating the nee...

  12. Carbohydrate-active enzymes from the zygomycete fungus Rhizopus oryzae: a highly specialized approach to carbohydrate degradation depicted at genome level

    Directory of Open Access Journals (Sweden)

    Henrissat Bernard

    2011-01-01

    Full Text Available Abstract Background Rhizopus oryzae is a zygomycete filamentous fungus, well-known as a saprobe ubiquitous in soil and as a pathogenic/spoilage fungus, causing Rhizopus rot and mucomycoses. Results Carbohydrate Active enzyme (CAZy annotation of the R. oryzae identified, in contrast to other filamentous fungi, a low number of glycoside hydrolases (GHs and a high number of glycosyl transferases (GTs and carbohydrate esterases (CEs. A detailed analysis of CAZy families, supported by growth data, demonstrates highly specialized plant and fungal cell wall degrading abilities distinct from ascomycetes and basidiomycetes. The specific genomic and growth features for degradation of easily digestible plant cell wall mono- and polysaccharides (starch, galactomannan, unbranched pectin, hexose sugars, chitin, chitosan, β-1,3-glucan and fungal cell wall fractions suggest specific adaptations of R. oryzae to its environment. Conclusions CAZy analyses of the genome of the zygomycete fungus R. oryzae and comparison to ascomycetes and basidiomycete species revealed how evolution has shaped its genetic content with respect to carbohydrate degradation, after divergence from the Ascomycota and Basidiomycota.

  13. Unwinding motion of a twisted active-region filament

    CERN Document Server

    Yan, X L; Liu, J H; Kong, D F; Xu, C L

    2014-01-01

    To better understand the structures of active-region filaments and the eruption process, we study an active-region filament eruption in active region NOAA 11082 in detail on June 22, 2010. Before the filament eruption, the opposite unidirectional material flows appeared in succession along the spine of the filament. The rising of the filament triggered two B-class flares at the upper part of the filament. As the bright material was injected into the filament from the sites of the flares, the filament exhibited a rapid uplift accompanying the counterclockwise rotation of the filament body. From the expansion of the filament, we can see that the filament is consisted of twisted magnetic field lines. The total twist of the filament is at least 5$\\pi$ obtained by using time slice method. According to the morphology change during the filament eruption, it is found that the active-region filament was a twisted flux rope and its unwinding motion was like a solar tornado. We also find that there was a continuous magn...

  14. The Enterobacterium Trabulsiella odontotermitis Presents Novel Adaptations Related to Its Association with Fungus-Growing Termites

    Science.gov (United States)

    Gruntjes, Thijs; Otani, Saria; Estevez, James; da Costa, Rafael R.; Plunkett, Guy; Perna, Nicole T.; Poulsen, Michael

    2015-01-01

    Fungus-growing termites rely on symbiotic microorganisms to help break down plant material and to obtain nutrients. Their fungal cultivar, Termitomyces, is the main plant degrader and food source for the termites, while gut bacteria complement Termitomyces in the degradation of foodstuffs, fixation of nitrogen, and metabolism of amino acids and sugars. Due to the community complexity and because these typically anaerobic bacteria can rarely be cultured, little is known about the physiological capabilities of individual bacterial members of the gut communities and their associations with the termite host. The bacterium Trabulsiella odontotermitis is associated with fungus-growing termites, but this genus is generally understudied, with only two described species. Taking diverse approaches, we obtained a solid phylogenetic placement of T. odontotermitis among the Enterobacteriaceae, investigated the physiology and enzymatic profiles of T. odontotermitis isolates, determined the localization of the bacterium in the termite gut, compared draft genomes of two T. odontotermitis isolates to those of their close relatives, and examined the expression of genes relevant to host colonization and putative symbiont functions. Our findings support the hypothesis that T. odontotermitis is a facultative symbiont mainly located in the paunch compartment of the gut, with possible roles in carbohydrate metabolism and aflatoxin degradation, while displaying adaptations to association with the termite host, such as expressing genes for a type VI secretion system which has been demonstrated to assist bacterial competition, colonization, and survival within hosts. PMID:26162887

  15. Pulmonary infections by the fungus aspergillus

    Directory of Open Access Journals (Sweden)

    Rao P

    1979-01-01

    Full Text Available Five cases of respiratory infection by Aspergillus fumigates are described. Species of aspergillus is ubiquitous in nature. Therefore, repeated demonstration of fungus, serological evidence tend radiological findings are essential for diagnosis. Potassium iodide is a useful drug in aspergillus infection of the lung when other drugs are not available. Injection Emetine hydrochloride is promising as a therapeutic agent in pulmonary aspergillosis, where the lung parenchyma is involved.

  16. Flexible magnetic filaments in a shear flow

    Energy Technology Data Exchange (ETDEWEB)

    Cebers, Andrejs [Institute of Physics, University of Latvia, Salaspils-1 LV-2169 (Latvia)]. E-mail: aceb@tesla.sal.lv

    2006-05-15

    By flexible magnetic filament model its behavior under the simultaneous action of the shear flow and the magnetic field is investigated. It is found that for magnetoelastic numbers larger as the critical value, which depends on the shear rate, the periodic regime is established. For the values of the magnetoelastic number close to the critical the periodical regime is characterized by a rather slow development of the buckling instability due to the action of magnetic torques with the subsequent stage of the fast straightening of the filament. For the magnetoelastic numbers below the critical slightly bent shape of the filament orientated along the flow is established. The application of the results for the description of the viscoelasticity of the magnetorheological suspensions is discussed.

  17. Reduced filamentation in high power semiconductor lasers

    DEFF Research Database (Denmark)

    Skovgaard, Peter M. W.; McInerney, John; O'Brien, Peter

    1999-01-01

    High brightness semiconductor lasers have applications in fields ranging from material processing to medicine. The main difficulty associated with high brightness is that high optical power densities cause damage to the laser facet and thus require large apertures. This, in turn, results in spatio......-temporal instabilities such as filamentation which degrades spatial coherence and brightness. We first evaluate performance of existing designs with a “top-hat” shaped transverse current density profile. The unstable nature of highly excited semiconductor material results in a run-away process where small modulations...... in the optical field causes spatial hole-burning and thus filamentation. To reduce filamentation we propose a new, relatively simple design based on inhomogeneous pumping in which the injected current has a gradual transverse profile. We confirm the improved laser performance theoretically and experimentally...

  18. Filament velocity scaling laws for warm ions

    Energy Technology Data Exchange (ETDEWEB)

    Manz, P. [Physik-Department E28, Technische Universität München, James-Franck-Str. 1, 85748 Garching (Germany); Max-Planck-Institut für Plasmaphysik, EURATOM Assoziation, Boltzmannstr. 2, 85748 Garching (Germany); Carralero, D.; Birkenmeier, G.; Müller, H. W.; Scott, B. D. [Max-Planck-Institut für Plasmaphysik, EURATOM Assoziation, Boltzmannstr. 2, 85748 Garching (Germany); Müller, S. H. [Center for Momentum Transport and Flow Organization, University of California at San Diego, San Diego 92093 (United States); Fuchert, G. [Insitut für Grenzflächenverfahrenstechnik und Plasmatechnologie, Universität Stuttgart, 70569 Stuttgart (Germany); Stroth, U. [Max-Planck-Institut für Plasmaphysik, EURATOM Assoziation, Boltzmannstr. 2, 85748 Garching (Germany); Physik-Department E28, Technische Universität München, James-Franck-Str. 1, 85748 Garching (Germany)

    2013-10-15

    The dynamics of filaments or blobs in the scrape-off layer of magnetic fusion devices are studied by magnitude estimates of a comprehensive drift-interchange-Alfvén fluid model. The standard blob models are reproduced in the cold ion case. Even though usually neglected, in the scrape-off layer, the ion temperature can exceed the electron temperature by an order of magnitude. The ion pressure affects the dynamics of filaments amongst others by adding up to the interchange drive and the polarisation current. It is shown how both effects modify the scaling laws for filament velocity in dependence of its size. Simplifications for experimentally relevant limit regimes are given. These are the sheath dissipation, collisional, and electromagnetic regime.

  19. Filament velocity scaling laws for warm ions

    Science.gov (United States)

    Manz, P.; Carralero, D.; Birkenmeier, G.; Müller, H. W.; Müller, S. H.; Fuchert, G.; Scott, B. D.; Stroth, U.

    2013-10-01

    The dynamics of filaments or blobs in the scrape-off layer of magnetic fusion devices are studied by magnitude estimates of a comprehensive drift-interchange-Alfvén fluid model. The standard blob models are reproduced in the cold ion case. Even though usually neglected, in the scrape-off layer, the ion temperature can exceed the electron temperature by an order of magnitude. The ion pressure affects the dynamics of filaments amongst others by adding up to the interchange drive and the polarisation current. It is shown how both effects modify the scaling laws for filament velocity in dependence of its size. Simplifications for experimentally relevant limit regimes are given. These are the sheath dissipation, collisional, and electromagnetic regime.

  20. Heterologous expression of cellobiohydrolases in filamentous fungi

    DEFF Research Database (Denmark)

    Zoglowek, Marta; Lübeck, Peter S.; Ahring, Birgitte K.

    2015-01-01

    Cellobiohydrolases are among the most important enzymes functioning in the hydrolysis of crystalline cellulose, significantly contributing to the efficient biorefining of recalcitrant lignocellulosic biomass into biofuels and bio-based products. Filamentous fungi are recognized as both well...... into valuable products. However, due to low cellobiohydrolase activities, certain fungi might be deficient with regard to enzymes of value for cellulose conversion, and improving cellobiohydrolase expression in filamentous fungi has proven to be challenging. In this review, we examine the effects of altering...... promoters, signal peptides, culture conditions and host post-translational modifications. For heterologous cellobiohydrolase production in filamentous fungi to become an industrially feasible process, the construction of site-integrating plasmids, development of protease-deficient strains and glycosylation...

  1. Oscillating Filaments: I - Oscillation and Geometrical Fragmentation

    CERN Document Server

    Gritschneder, Matthias; Burkert, Andreas

    2016-01-01

    We study the stability of filaments in equilibrium between gravity and internal as well as external pressure using the grid based AMR-code RAMSES. A homogeneous, straight cylinder below a critical line mass is marginally stable. However, if the cylinder is bent, e.g. with a slight sinusoidal perturbation, an otherwise stable configuration starts to oscillate, is triggered into fragmentation and collapses. This previously unstudied behavior allows a filament to fragment at any given scale, as long as it has slight bends. We call this process `geometrical fragmentation'. In our realization the spacing between the cores matches the wavelength of the sinusoidal perturbation, whereas up to now, filaments were thought to be only fragmenting on the characteristical scale set by the mass-to-line ratio. Using first principles, we derive the oscillation period as well as the collapse timescale analytically. To enable a direct comparison with observations, we study the line-of-sight velocity for different inclinations. ...

  2. Potential for anaerobic conversion of xenobiotics

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Dolfing, J.; Haagensen, Frank;

    2003-01-01

    This review covers the latest research on the anaerobic biodegradation of aromatic xenobiotic compounds, with emphasis on surfactants, polycyclic aromatic hydrocarbons, phthalate esters, polychlorinated biphenyls, halogenated phenols, and pesticides. The versatility of anaerobic reactor systems...

  3. RISK FACTORS IN NEONATAL ANAEROBIC INFECTIONS

    Directory of Open Access Journals (Sweden)

    M. S. Tabib

    2008-06-01

    Full Text Available Anaerobic bacteria are well known causes of sepsis in adults but there are few studies regarding their role in neonatal sepsis. In an attempt to define the incidence of neonatal anaerobic infections a prospective study was performed during one year period. A total number of 400 neonates under sepsis study were entered this investigation. Anaerobic as well as aerobic cultures were sent. The patients were subjected to comparison in two groups: anaerobic culture positive and anaerobic culture negative and this comparison were analyzed statistically. There were 7 neonates with positive anaerobic culture and 35 neonates with positive aerobic culture. A significant statistical relationship was found between anaerobic infections and abdominal distention and pneumonia. It is recommended for those neonates with abdominal distention and pneumonia refractory to antibiotic treatment to be started on antibiotics with anaerobic coverage.

  4. Arsenic, Anaerobes, and Astrobiology

    Science.gov (United States)

    Stolz, J. F.; Oremland, R. S.; Switzer Blum, J.; Hoeft, S. E.; Baesman, S. M.; Bennett, S.; Miller, L. G.; Kulp, T. R.; Saltikov, C.

    2013-12-01

    Arsenic is an element best known for its highly poisonous nature, so it is not something one would associate with being a well-spring for life. Yet discoveries made over the past two decades have delineated that not only are some microbes resistant to arsenic, but that this element's primary redox states can be exploited to conserve energy and support prokaryotic growth ('arsenotrophy') in the absence of oxygen. Hence, arsenite [As(III)] can serve as an electron donor for chemo- or photo-autotrophy while arsenate [As(V)] will serve as an electron acceptor for chemo-heterotrophs and chemo-autotrophs. The phylogenetic diversity of these microbes is broad, encompassing many individual species from diverse taxonomic groups in the Domain Bacteria, with fewer representatives in the Domain Archaea. Speculation with regard to the evolutionary origins of the key functional genes in anaerobic arsenic transformations (arrA and arxA) and aerobic oxidation (aioB) has led to a disputation as to which gene and function is the most ancient and whether arsenic metabolism extended back into the Archaean. Regardless of its origin, robust arsenic metabolism has been documented in extreme environments that are rich in their arsenic content, such as hot springs and especially hypersaline soda lakes associated with volcanic regions. Searles Lake, CA is an extreme, salt-saturated end member where vigorous arsenic metabolism occurs, but there is no detectable sulfate-reduction or methanogenesis. The latter processes are too weak bio-energetically to survive as compared with arsenotrophy, and are also highly sensitive to the abundance of borate ions present in these locales. These observations have implications with respect to the search for microbial life elsewhere in the Solar System where volcanic-like processes have been operative. Hence, because of the likelihood of encountering dense brines in the regolith of Mars (formed by evapo-concentration) or beneath the ice layers of Europa

  5. Generation of stable overlaps between antiparallel filaments

    CERN Document Server

    Johann, D; Kruse, K

    2015-01-01

    During cell division, sister chromatids are segregated by the mitotic spindle, a bipolar assembly of interdigitating antiparallel polar filaments called microtubules. Establishing a stable overlap region is essential for maintenance of bipolarity, but the underlying mechanisms are poorly understood. Using a particle-based stochastic model, we find that the interplay of motors and passive cross linkers can robustly generate partial overlaps between antiparallel filaments. Our analysis shows that motors reduce the overlap in a length-dependent manner, whereas passive cross linkers increase it independently of the length. In addition to maintaining structural integrity, passive cross linkers can thus also have a dynamic role for size regulation.

  6. Filament stretching rheometer: inertia compensation revisited

    DEFF Research Database (Denmark)

    Szabo, Peter; McKinley, Gareth H.

    2003-01-01

    The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end of the e......The necessary inertia compensation used in the force balance for the filament stretching rheometer is derived for an arbitrary frame of reference. This enables the force balance to be used to extract correctly the extensional viscosity from measurements of the tensile force at either end...

  7. The exo-metabolome in filamentous fungi

    DEFF Research Database (Denmark)

    Thrane, Ulf; Andersen, Birgitte; Frisvad, Jens Christian

    2007-01-01

    Filamentous fungi are a diverse group of eukaryotic microorganisms that have a significant impact on human life as spoilers of food and feed by degradation and toxin production. They are also most useful as a source of bulk and fine chemicals and pharmaceuticals. This chapter focuses on the exo......-metabolome in filamentous fungi, which comprises more than 30,000 known secondary metabolites. Profiles of this diverse range of secondary metabolites have, for more than 25 years, been central in development of fungal systematics, taxonomy, and ecology, today integrated in a multidisciplinary and polyphasic approach...

  8. On the nature of star-forming filaments: I. Filament morphologies

    CERN Document Server

    Smith, Rowan J; Klessen, Ralf S

    2014-01-01

    We use a suite of high resolution molecular cloud simulations carried out with the moving mesh code Arepo to explore the nature of star-forming filaments. The simulated filaments are identified and categorised from column density maps in the same manner as for recent Herschel observations. When fit with a Plummer-like profile the filaments are in excellent agreement with observations, and have shallow power-law profiles of p~2.2 without the need for magnetic support. The derived filament widths depend on the data range that is fitted. When data within 1 pc of the filament centre is fitted with a Gaussian function, the average FWHM is ~0.3 pc, in agreement with predictions for accreting filaments. However, if the fit is constructed using only data within 0.35 pc of the centre, in order to better match the procedure used to derive filament widths from Herschel observations, the resulting FWHM is only ~0.2 pc. This value is larger than that measured in IC 5146 and Taurus, but is similar to that found in the Plan...

  9. Abundance and dynamics of filamentous fungi in the complex ambrosia gardens of the primitively eusocial beetle Xyleborinus saxesenii Ratzeburg (Coleoptera: Curculionidae, Scolytinae).

    Science.gov (United States)

    Biedermann, Peter H W; Klepzig, Kier D; Taborsky, Michael; Six, Diana L

    2013-03-01

    Insect fungus gardens consist of a community of interacting microorganisms that can have either beneficial or detrimental effects to the farmers. In contrast to fungus-farming ants and termites, the fungal communities of ambrosia beetles and the effects of particular fungal species on the farmers are largely unknown. Here, we used a laboratory rearing technique for studying the filamentous fungal garden community of the ambrosia beetle, Xyleborinus saxesenii, which cultivates fungi in tunnels excavated within dead trees. Raffaelea sulfurea and Fusicolla acetilerea were transmitted in spore-carrying organs by gallery founding females and established first in new gardens. Raffaelea sulfurea had positive effects on egg-laying and larval numbers. Over time, four other fungal species emerged in the gardens. Prevalence of one of them, Paecilomyces variotii, correlated negatively with larval numbers and can be harmful to adults by forming biofilms on their bodies. It also comprised the main portion of garden material removed from galleries by adults. Our data suggest that two mutualistic, several commensalistic and one to two pathogenic filamentous fungi are associated with X. saxesenii. Fungal diversity in gardens of ambrosia beetles appears to be much lower than that in gardens of fungus-culturing ants, which seems to result from essential differences in substrates and behaviours.

  10. 21 CFR 866.2120 - Anaerobic chamber.

    Science.gov (United States)

    2010-04-01

    ... and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES IMMUNOLOGY AND MICROBIOLOGY DEVICES Microbiology Devices § 866.2120 Anaerobic chamber. (a) Identification. An anaerobic chamber is a device intended for medical purposes to maintain an anaerobic...

  11. The phenomenon of granulation of anaerobic sludge.

    NARCIS (Netherlands)

    Hulshoff Pol, L.W.

    1989-01-01

    Successful high-rate anaerobic wastewater treatment can only be accomplished when the slowgrowing anaerobic biomass is efficiently held back in the anaerobic treatment system. This biomass retention can be achieved in various ways including immobilization of the organisms on fixed materials and immo

  12. Fungus-Growing Termites Originated in African Rain Forest

    DEFF Research Database (Denmark)

    Aanen, Duur Kornelis; Eggleton, Paul

    2005-01-01

    are consumed (cf. [ [1] and [2] ]). Fungus-growing termites are found throughout the Old World tropics, in rain forests and savannas, but are ecologically dominant in savannas [ 3 ]. Here, we reconstruct the ancestral habitat and geographical origin of fungus-growing termites. We used a statistical model......Fungus-growing termites (subfamily Macrotermitinae, Isoptera) cultivate fungal crops (genus Termitomyces, Basidiomycotina) in gardens inside their colonies. Those fungus gardens are continuously provided with plant substrates, whereas older parts that have been well decomposed by the fungus...... extant savanna species are found in most genera, this moreover suggests that the savanna has repeatedly been colonized by fungus-growing termites. Furthermore, at least four independent "out-of-Africa" migrations into Asia, and at least one independent migration to Madagascar, have occurred. Although...

  13. Decomposition of Plant Debris by the Nematophagous Fungus ARF

    OpenAIRE

    Wang, Kening; Riggs, R. D.; Crippen, Devany

    2004-01-01

    In the study of the biological control of plant-parasitic nematodes, knowledge of the saprophytic ability of a nematophagous fungus is necessary to understand its establishment and survival in the soil. The objectives of this study were (i) to determine if the nematophagous fungus ARF (Arkansas Fungus) shows differential use of plant residues; and (ii) to determine if ARF still existed in the soil of a field in which ARF was found originally and in which the population level of Heterodera gly...

  14. Perspectives of Anaerobic Soil Disinfestation

    NARCIS (Netherlands)

    Lamers, J.G.; Runia, W.T.; Molendijk, L.P.G.; Bleeker, P.O.

    2010-01-01

    Biological soil disinfestation is an environmentally friendly method to disinfest soil. From now on we refer to it as anaerobic soil disinfestation (ASD). With ASD a green manure crop (40 t/ha) is homogeneously incorporated into the topsoil (0-30 cm) after which the field is lightly compacted and ir

  15. Modelling the morphology of filamentous microorganisms

    DEFF Research Database (Denmark)

    Nielsen, Jens Bredal

    1996-01-01

    The rapid development in image analysis techniques has made it possible to study the growth kinetics of filamentous microorganisms in more detail than previously, However, owing to the many different processes that influence the morphology it is important to apply mathematical models to extract...

  16. Using Drosophila for Studies of Intermediate Filaments.

    Science.gov (United States)

    Bohnekamp, Jens; Cryderman, Diane E; Thiemann, Dylan A; Magin, Thomas M; Wallrath, Lori L

    2016-01-01

    Drosophila melanogaster is a useful organism for determining protein function and modeling human disease. Drosophila offers a rapid generation time and an abundance of genomic resources and genetic tools. Conservation in protein structure, signaling pathways, and developmental processes make studies performed in Drosophila relevant to other species, including humans. Drosophila models have been generated for neurodegenerative diseases, muscular dystrophy, cancer, and many other disorders. Recently, intermediate filament protein diseases have been modeled in Drosophila. These models have revealed novel mechanisms of pathology, illuminated potential new routes of therapy, and make whole organism compound screens feasible. The goal of this chapter is to outline steps to study intermediate filament function and model intermediate filament-associated diseases in Drosophila. The steps are general and can be applied to study the function of almost any protein. The protocols outlined here are for both the novice and experienced Drosophila researcher, allowing the rich developmental and cell biology that Drosophila offers to be applied to studies of intermediate filaments.

  17. Filament stretching rheometry of polymer melts

    DEFF Research Database (Denmark)

    Hassager, Ole; Nielsen, Jens Kromann; Rasmussen, Henrik Koblitz

    2005-01-01

    The Filament Stretching Rheometry (FSR) method developed by Sridhar, McKinley and coworkers for polymer solutions has been extended to be used also for polymer melts. The design of a melt-FSR will be described and differences to conventional melt elongational rheometers will be pointed out. Results...

  18. Linear viscoelastic characterization from filament stretching rheometry

    DEFF Research Database (Denmark)

    Wingstrand, Sara Lindeblad; Alvarez, Nicolas J.; Hassager, Ole

    viscoelasticity well into the nonlinear regime. Therefore at present, complete rheological characterization of a material requires two apparatuses: a shear and an extensional rheometer. This work is focused on developing a linear viscoelastic protocol for the filament stretching rheometer (FSR) in order...

  19. Self-assembly of Artificial Actin Filaments

    Science.gov (United States)

    Grosenick, Christopher; Cheng, Shengfeng

    Actin Filaments are long, double-helical biopolymers that make up the cytoskeleton along with microtubules and intermediate filaments. In order to further understand the self-assembly process of these biopolymers, a model to recreate actin filament geometry was developed. A monomer in the shape of a bent rod with vertical and lateral binding sites was designed to assemble into single or double helices. With Molecular Dynamics simulations, a variety of phases were observed to form by varying the strength of the binding sites. Ignoring lateral binding sites, we have found a narrow range of binding strengths that lead to long single helices via various growth pathways. When lateral binding strength is introduced, double helices begin to form. These double helices self-assemble into substantially more stable structures than their single helix counterparts. We have found double helices to form long filaments at about half the vertical binding strength of single helices. Surprisingly, we have found that triple helices occasionally form, indicating the importance of structural regulation in the self-assembly of biopolymers.

  20. Filament eruption with apparent reshuffle of endpoints

    CERN Document Server

    Filippov, Boris

    2014-01-01

    Filament eruption on 30 April - 1 May 2010, which shows the reconnection of one filament leg with a region far away from its initial position, is analyzed. Observations from three viewpoints are used for as precise as possible measurements of endpoint coordinates. The northern leg of the erupting prominence loop 'jumps' laterally to the latitude lower than the latitude of the originally southern endpoint. Thus, the endpoints reshuffled their positions in the limb view. Although this behaviour could be interpreted as the asymmetric zipping-like eruption, it does not look very likely. It seems more likely to be reconnection of the flux-rope field lines in its northern leg with ambient coronal magnetic field lines rooted in a quiet region far from the filament. From calculations of coronal potential magnetic field, we found that the filament before the eruption was stable for vertical displacements, but was liable to violation of the horizontal equilibrium. This is unusual initiation of an eruption with combinat...

  1. The Apis mellifera filamentous virus genome

    Science.gov (United States)

    A complete reference genome of the Apis mellifera Filamentous virus (AmFV) was determined using Illumina Hiseq sequencing. The AmFV genome is a double strand DNA molecule of approximately 498’500 nucleotides with a GC content of 50.8%. It encompasses 251 non overlapping open reading frames (ORFs), e...

  2. Filamentous bacteria transport electrons over centimetre distances

    DEFF Research Database (Denmark)

    Pfeffer, Christian; Larsen, Steffen; Song, Jie

    2012-01-01

    across centimetre-wide zones. Here we present evidence that the native conductors are long, filamentous bacteria. They abounded in sediment zones with electric currents and along their length they contained strings with distinct properties in accordance with a function as electron transporters. Living...

  3. Phosphatidylinositol-4-phosphate-dependent membrane traffic is critical for fungal filamentous growth.

    Science.gov (United States)

    Ghugtyal, Vikram; Garcia-Rodas, Rocio; Seminara, Agnese; Schaub, Sébastien; Bassilana, Martine; Arkowitz, Robert Alan

    2015-07-14

    The phospholipid phosphatidylinositol-4-phosphate [PI(4)P], generated at the Golgi and plasma membrane, has been implicated in many processes, including membrane traffic, yet its role in cell morphology changes, such as the budding to filamentous growth transition, is unknown. We show that Golgi PI(4)P is required for such a transition in the human pathogenic fungus Candida albicans. Quantitative analyses of membrane traffic revealed that PI(4)P is required for late Golgi and secretory vesicle dynamics and targeting and, as a result, is important for the distribution of a multidrug transporter and hence sensitivity to antifungal drugs. We also observed that plasma membrane PI(4)P, which we show is functionally distinct from Golgi PI(4)P, forms a steep gradient concomitant with filamentous growth, despite uniform plasma membrane PI-4-kinase distribution. Mathematical modeling indicates that local PI(4)P generation and hydrolysis by phosphatases are crucial for this gradient. We conclude that PI(4)P-regulated membrane dynamics are critical for morphology changes.

  4. Interaction of Two Filament Channels of Different Chiralities

    CERN Document Server

    Joshi, Navin Chandra; Schmieder, Brigitte; Magara, Tetsuya; Moon, Young-Jae; Uddin, Wahab

    2016-01-01

    We present observations of interactions between the two filament channels of different chiralities and associated dynamics that occurred during 2014 April 18 -- 20. While two flux ropes of different helicity with parallel axial magnetic fields can only undergo a bounce interaction when they are brought together, the observations at the first glance show that the heated plasma is moving from one filament channel to the other. The SDO/AIA 171 A observations and the PFSS magnetic field extrapolation reveal the presence of fan-spine magnetic configuration over the filament channels with a null point located above them. Three different events of filament activations, partial eruptions, and associated filament channel interactions have been observed. The activation initiated in one filament channel seems to propagate along the neighbour filament channel. We believe that the activation and partial eruption of the filaments bring the field lines of flux ropes containing them closer to the null point and trigger the m...

  5. Assembly characteristics of plant keratin intermediate filaments in vitro

    Institute of Scientific and Technical Information of China (English)

    闵光伟; 杨澄; 佟向军; 翟中和

    1999-01-01

    After selective extraction and purification, plant keratin intermediate filaments were reassembled in vitro. Scanning tunneling microscope (STM) and transmission electron microscope (TEM) micrographs showed that acidic keratins and basic keratins can assemble into dimers and further into 10 nm filaments in vitro. In higher magnification images, it can be seen that fully assembled plant keratin intermediate filaments consist of several thinner filaments of 3 nm in diameter, which indicates the formation of protofilaments in the assembly processes. One of the explicit features of plant keratin intermediate filaments is a 24—25 nm periodic structural repeat alone the axis of beth the 10 nm filaments and protofilaments. The periodic repeat is one of the fundamental characteristic of all intermediate filaments, and demonstrates the half staggered arrangement of keratin molecules within the filaments.

  6. Anaerobic granular sludge and biofilm reactors

    DEFF Research Database (Denmark)

    Skiadas, Ioannis V.; Gavala, Hariklia N.; Schmidt, Jens Ejbye

    2003-01-01

    by the immobilization of the biomass, which forms static biofilms, particle-supported biofilms, or granules depending on the reactor's operational conditions. The advantages of the high-rate anaerobic digestion over the conventional aerobic wastewater treatment methods has created a clear trend for the change......-rate anaerobic treatment systems based on anaerobic granular sludge and biofilm are described in this chapter. Emphasis is given to a) the Up-flow Anaerobic Sludge Blanket (UASB) systems, b) the main characteristics of the anaerobic granular sludge, and c) the factors that control the granulation process...

  7. Symbiotic fungi produce laccases potentially involved in phenol degradation in fungus combs of fungus-growing termites in Thailand.

    Science.gov (United States)

    Taprab, Yaovapa; Johjima, Toru; Maeda, Yoshimasa; Moriya, Shigeharu; Trakulnaleamsai, Savitr; Noparatnaraporn, Napavarn; Ohkuma, Moriya; Kudo, Toshiaki

    2005-12-01

    Fungus-growing termites efficiently decompose plant litter through their symbiotic relationship with basidiomycete fungi of the genus Termitomyces. Here, we investigated phenol-oxidizing enzymes in symbiotic fungi and fungus combs (a substrate used to cultivate symbiotic fungi) from termites belonging to the genera Macrotermes, Odontotermes, and Microtermes in Thailand, because these enzymes are potentially involved in the degradation of phenolic compounds during fungus comb aging. Laccase activity was detected in all the fungus combs examined as well as in the culture supernatants of isolated symbiotic fungi. Conversely, no peroxidase activity was detected in any of the fungus combs or the symbiotic fungal cultures. The laccase cDNA fragments were amplified directly from RNA extracted from fungus combs of five termite species and a fungal isolate using degenerate primers targeting conserved copper binding domains of basidiomycete laccases, resulting in a total of 13 putative laccase cDNA sequences being identified. The full-length sequences of the laccase cDNA and the corresponding gene, lcc1-2, were identified from the fungus comb of Macrotermes gilvus and a Termitomyces strain isolated from the same fungus comb, respectively. Partial purification of laccase from the fungus comb showed that the lcc1-2 gene product was a dominant laccase in the fungus comb. These findings indicate that the symbiotic fungus secretes laccase to the fungus comb. In addition to laccase, we report novel genes that showed a significant similarity with fungal laccases, but the gene product lacked laccase activity. Interestingly, these genes were highly expressed in symbiotic fungi of all the termite hosts examined.

  8. Flexible ferromagnetic filaments and the interface with biology

    Energy Technology Data Exchange (ETDEWEB)

    Erglis, K.; Belovs, M. [University of Latvia, Zellu 8, Riga LV-1002 (Latvia); Cebers, A. [University of Latvia, Zellu 8, Riga LV-1002 (Latvia)], E-mail: aceb@tesla.sal.lv

    2009-04-15

    Flexible ferromagnetic filaments are studied both theoretically and experimentally. Two main deformation modes of the filament at magnetic field inversion are theoretically described and observed experimentally by using DNA-linked chains of ferromagnetic particles. Anomalous orientation of ferromagnetic filaments perpendicular to AC field with a frequency which is high enough is predicted and confirmed experimentally. By experimental studies of magnetotactic bacteria it is demonstrated how these properties of ferromagnetic filaments may be used to measure the flexibility of the chain of magnetosomes.

  9. Understanding how commensal obligate anaerobic bacteria regulate immune functions in the large intestine.

    Science.gov (United States)

    Maier, Eva; Anderson, Rachel C; Roy, Nicole C

    2014-12-24

    The human gastrointestinal tract is colonised by trillions of commensal bacteria, most of which are obligate anaerobes residing in the large intestine. Appropriate bacterial colonisation is generally known to be critical for human health. In particular, the development and function of the immune system depends on microbial colonisation, and a regulated cross-talk between commensal bacteria, intestinal epithelial cells and immune cells is required to maintain mucosal immune homeostasis. This homeostasis is disturbed in various inflammatory disorders, such as inflammatory bowel diseases. Several in vitro and in vivo studies indicate a role for Faecalibacterium prausnitzii, Bacteroides thetaiotaomicron, Bacteroides fragilis, Akkermansia muciniphila and segmented filamentous bacteria in maintaining intestinal immune homeostasis. These obligate anaerobes are abundant in the healthy intestine but reduced in several inflammatory diseases, suggesting an association with protective effects on human health. However, knowledge of the mechanisms underlying the effects of obligate anaerobic intestinal bacteria remains limited, in part due to the difficulty of co-culturing obligate anaerobes together with oxygen-requiring human epithelial cells. By using novel dual-environment co-culture models, it will be possible to investigate the effects of the unstudied majority of intestinal microorganisms on the human epithelia. This knowledge will provide opportunities for improving human health and reducing the risk of inflammatory diseases.

  10. Effect of thermal hydrolysis and ultrasounds pretreatments on foaming in anaerobic digesters.

    Science.gov (United States)

    Alfaro, N; Cano, R; Fdz-Polanco, F

    2014-10-01

    Foam appears regularly in anaerobic digesters producing operational and safety problems. In this research, based on the operational observation at semi-industrial pilot scale where sludge pretreatment mitigated foaming in anaerobic digesters, this study aimed at evaluating any potential relationship between foaming tools applied to activated sludge at lab-scale (foam potential, foam stability and Microthrix parvicella abundance) and the experimental behavior observed in pilot scale and full-scale anaerobic digesters. The potential of thermal hydrolysis and ultrasounds for reducing foaming capacity was also evaluated. Filamentous bacteria abundance was directly linked to foaming capacity in anaerobic processes. A maximum reduction of M.parvicella abundance (from 5 to 2) was reached using thermal hydrolysis with steam explosion at 170°C and ultrasounds at 66.7kWh/m(3), showing both good anti-foaming properties. On the other hand, foam potential and stability determinations showed a lack of consistency with the bacteria abundance results and experimental evidences.

  11. Sterols from the Fungus Catathelasma imperiale

    Institute of Scientific and Technical Information of China (English)

    YANG, Sheng-Ping; XU, Jun; YUE, Jian-Min

    2003-01-01

    Eight ergostane-type sterols and three their derivatives (one mono-linoleate and two mono-glucosides) were isolated from the ethyl acetate soluble fraction of the fungus Catathelasma imperiale. Two of them are novel compounds, namely 22E, 24R-ergosta-7,22-diene-3β, 5α-diol-6β-linoleate (1) and 22E, 24R-ergosta-7,22-diene-3β,5β,6α-triol (5) with an uncommon cisfused A/B ring. Structures of these compounds were demonstrated on the basis of their chemical evidences and spectroscopic methods, especially 2D NMR techniques.

  12. Metabolites from mangrove endophytic fungus Dothiorella sp.

    Institute of Scientific and Technical Information of China (English)

    XUQingyan; WANGJianfeng; HUANGYaojian; ZHENGZhonghui; SONGSiyang; ZHANGYongmin; SUWenjin

    2004-01-01

    Mangroves are special woody plant communities in the intertidal zone of tropical and subtropical coasts. They prove to be a natural microorganisms and new metabolites storage. In the study of mangrove endophytic fungi metabolites, four new compounds, Compounds 1, 2, 3 and 4, as well as a known octaketide, cytosporone B (5), are isolated from an endophytic fungus, Dothiorella sp., HTF3. They all show cytotoxic activities. The elucidation of these structures is mainly based on 1D/2D NMR and ESI-MS spectral analyses.

  13. Induction of Th17 cells by segmented filamentous bacteria in the murine intestine.

    Science.gov (United States)

    Farkas, Adam M; Panea, Casandra; Goto, Yoshiyuki; Nakato, Gaku; Galan-Diez, Marta; Narushima, Seiko; Honda, Kenya; Ivanov, Ivaylo I

    2015-06-01

    Segmented filamentous bacteria (SFB) are Gram-positive, anaerobic, spore-forming commensals that reside in the gut of many animal species. Described more than forty years ago, SFB have recently gained interest due to their unique ability to modulate the host immune system through induction of IgA and Th17 cells. Here, we describe a collection of methods to detect and quantify SFB and SFB adhesion in intestinal mucosa, as well as SFB-specific CD4 T cells in the lamina propria. In addition, we describe methods for purification of SFB from fecal material of SFB-monoassociated gnotobiotic mice. Using these methods we examine the kinetics of SFB colonization and Th17 cell induction. We also show that SFB colonize unevenly the intestinal mucosa and that SFB adherence occurs predominantly in the terminal ileum and correlates with an increased proportion of SFB-specific Th17 cells.

  14. Genome Sequence of the Pathogenic Fungus Sporothrix schenckii (ATCC 58251).

    Science.gov (United States)

    Cuomo, Christina A; Rodriguez-Del Valle, Nuri; Perez-Sanchez, Lizaida; Abouelleil, Amr; Goldberg, Jonathan; Young, Sarah; Zeng, Qiandong; Birren, Bruce W

    2014-05-22

    Sporothrix schenckii is a pathogenic dimorphic fungus that grows as a yeast and as mycelia. This species is the causative agent of sporotrichosis, typically a skin infection. We report the genome sequence of S. schenckii, which will facilitate the study of this fungus and of the Sporothrix schenckii group.

  15. Expanding Distribution of Lethal Amphibian Fungus Batrachochytrium salamandrivorans in Europe.

    Science.gov (United States)

    Spitzen-van der Sluijs, Annemarieke; Martel, An; Asselberghs, Johan; Bales, Emma K; Beukema, Wouter; Bletz, Molly C; Dalbeck, Lutz; Goverse, Edo; Kerres, Alexander; Kinet, Thierry; Kirst, Kai; Laudelout, Arnaud; Marin da Fonte, Luis F; Nöllert, Andreas; Ohlhoff, Dagmar; Sabino-Pinto, Joana; Schmidt, Benedikt R; Speybroeck, Jeroen; Spikmans, Frank; Steinfartz, Sebastian; Veith, Michael; Vences, Miguel; Wagner, Norman; Pasmans, Frank; Lötters, Stefan

    2016-07-01

    Emerging fungal diseases can drive amphibian species to local extinction. During 2010-2016, we examined 1,921 urodeles in 3 European countries. Presence of the chytrid fungus Batrachochytrium salamandrivorans at new locations and in urodeles of different species expands the known geographic and host range of the fungus and underpins its imminent threat to biodiversity.

  16. Fungus-associated bacteriome in charge of their host behaviour

    NARCIS (Netherlands)

    Schulz-Bohm, Kristin; Tyc, Olaf; Boer, Wietse de; Peereboom, Nils; Debets, Fons; Zaagman, Niels; Janssens, Thierry K.S.; Garbeva, Paolina

    2016-01-01

    Abstract Bacterial-fungal interactions are widespread in nature and there is a growing number of studies reporting distinct fungus-associated bacteria. However, little is known so far about how shifts in the fungus-associated bacteriome will affect the fungal host’s lifestyle. In the present study,

  17. Fungus-associated bacteriome in charge of their host behavior

    NARCIS (Netherlands)

    Schulz-Bohm, Kristin; Tyc, Olaf; Boer, de Wietse; Peereboom, Nils; Debets, Fons; Zaagman, Niels; Janssens, Thierry K.S.; Garbeva, Paolina

    2016-01-01

    Bacterial-fungal interactions are widespread in nature and there is a growing number of studies reporting distinct fungus-associated bacteria. However, little is known so far about how shifts in the fungus-associated bacteriome will affect the fungal host’s lifestyle. In the present study, we descri

  18. Reciprocal genomic evolution in the ant-fungus agricultural symbiosis

    DEFF Research Database (Denmark)

    Nygaard, Sanne; Hu, Haofu; Li, Cai;

    2016-01-01

    The attine ant-fungus agricultural symbiosis evolved over tens of millions of years, producing complex societies with industrial-scale farming analogous to that of humans. Here we document reciprocal shifts in the genomes and transcriptomes of seven fungus-farming ant species and their fungal...

  19. Reciprocal genomic evolution in the ant-fungus agricultural symbiosis

    DEFF Research Database (Denmark)

    Nygaard, Sanne; Hu, Haofu; Li, Cai;

    2016-01-01

    The attine ant-fungus agricultural symbiosis evolved over tens of millions of years, producing complex societies with industrial-scale farming analogous to that of humans. Here we document reciprocal shifts in the genomes and transcriptomes of seven fungus-farming ant species and their fungal cul...

  20. Ribonucleic acids in different tea fungus beverages

    Directory of Open Access Journals (Sweden)

    Malbaša Radomir V.

    2003-01-01

    Full Text Available In human nutrition, nucleic acids have to be balanced and limited up to 2 g/day because purines are degraded to urate, and excessive production of urate is a cause of gout which primarily affects adult males. Tea fungus beverage is a well known drink with high nutritional value and certain curative effects. Its benefits have been proved in a number of studies but it is still necessary to examine some potential harmful effects of this beverage. The aim of this paper was to investigate content of ribonucleic acids (RNA produced during tea fungus fermentation on a usual substrate sweetened black tea, and on Jerusalem artichoke tubers (J.A.T extract using method by Munro and Fleck (1966. pH, ribonucleic acids and also the production of proteins that affect purity of nucleic acids preparations were monitored. A higher value of RNA has been noticed in J.A.T. beverage (0.57 mg/ml and with observation of usual daily dose of the beverage it is completely safe and useful one.

  1. Antimicrobial chemical constituents from endophytic fungus Phomasp.

    Institute of Scientific and Technical Information of China (English)

    Hidayat Hussain; Siegfried Draeger; Barbara Schulz; Karsten Krohn; Ines Kock; Ahmed Al-Harrasi; Ahmed Al-Rawahi; Ghulam Abbas; Ivan R Green; Afzal Shah; Amin Badshah; Muhammad Saleem

    2014-01-01

    Objective:To evaluate the antimicrobial potential of different extracts of the endophytic fungus Phomasp. and the tentative identification of their active constituents.Methods:The extract and compounds were screened for antimicrobial activity using theAgarWellDiffusionMethod. Four compounds were purified using column chromatography and their structures were assigned using1H and13CNMR spectra,DEPT,2DCOSY,HMQC andHMBC experiments.Results:The ethyl acetate fraction ofPhomasp. showed good antifungal, antibacterial, and algicidal properties.One new dihydrofuran derivative, named phomafuranol(1), together with three known compounds, phomalacton(2),(3R)-5-hydroxymellein(3) and emodin(4) were isolated from the ethyl acetate fraction ofPhomasp.Preliminary studies indicated that phomalacton(2) displayed strong antibacterial, good antifungal and antialgal activities.Similarly(3R)-5-hydroxymellein (3) and emodin(4) showed good antifungal, antibacterial and algicidal properties.Conclusions:Antimicrobial activities of the ethyl acetate fraction of the endophytic fungusPhomasp. and isolated compounds clearly demonstrate thatPhomasp. and its active compounds represent a great potential for the food, cosmetic and pharmaceutical industries.

  2. New Development Trend of Edible Fungus Industry in China

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    We elaborate support system of edible fungus industry from outlook on ecological economic development, legislation and standardization of variety approval, multiple-function innovation platform of industrial development research, and perfect talent cultivation and education system. Besides, we analyze the development trend of edible fungus industry from competitive advantages, position and role in national food security, industrial development trend driven by internal demand, diversified industrial development model, division of labor within the industry, and expansion of industrial chain. Then, from the point of zoning and planning of edible fungus industry, we put forward suggestions that it should start from modern industrial system and take the industrial cluster development and optimization as guidance. In addition, we present technical innovation direction of industrial development. It is proposed to strengthen propaganda, build industrial cultural atmosphere, and expand social cognition degree of edible fungus industry to promote its redevelopment. Finally, it is expected to promote international influence of edible fungus industry through experts appealing for policy support.

  3. Morgellons disease: a filamentous borrelial dermatitis

    Science.gov (United States)

    Middelveen, Marianne J; Stricker, Raphael B

    2016-01-01

    Morgellons disease (MD) is a dermopathy characterized by multicolored filaments that lie under, are embedded in, or project from skin. Although MD was initially considered to be a delusional disorder, recent studies have demonstrated that the dermopathy is associated with tickborne infection, that the filaments are composed of keratin and collagen, and that they result from proliferation of keratinocytes and fibroblasts in epithelial tissue. Culture, histopathological and molecular evidence of spirochetal infection associated with MD has been presented in several published studies using a variety of techniques. Spirochetes genetically identified as Borrelia burgdorferi sensu stricto predominate as the infective agent in most of the Morgellons skin specimens studied so far. Other species of Borrelia including Borrelia garinii, Borrelia miyamotoi, and Borrelia hermsii have also been detected in skin specimens taken from MD patients. The optimal treatment for MD remains to be determined. PMID:27789971

  4. Merging and energy exchange between optical filaments

    Energy Technology Data Exchange (ETDEWEB)

    Georgieva, D. A., E-mail: dgeorgieva@tu-sofia.bg [Faculty of Applied Mathematics and Computer Science, Technical University of Sofia, 8 Kliment Ohridski Blvd., 1000 Sofia (Bulgaria); Kovachev, L. M. [Institute of Electronics, Bulgarian Academy of Sciences, 72 Tzarigradcko Chaussee Blvd., 1784 Sofia (Bulgaria)

    2015-10-28

    We investigate nonlinear interaction between collinear femtosecond laser pulses with power slightly above the critical for self-focusing P{sub cr} trough the processes of cross-phase modulation (CPM) and degenerate four-photon parametric mixing (FPPM). When there is no initial phase difference between the pulses we observe attraction between pulses due to CPM. The final result is merging between the pulses in a single filament with higher power. By method of moments it is found that the attraction depends on the distance between the pulses and has potential character. In the second case we study energy exchange between filaments. This process is described through FPPM scheme and requests initial phase difference between the waves.

  5. Intergalactic Filaments as Isothermal Gas Cylinders

    CERN Document Server

    Harford, A Gayler

    2010-01-01

    Using a cosmological simulation at redshift 5, we find that the baryon-rich cores of intergalactic filaments radiating from galaxies commonly form isothermal gas cylinders. The central gas density is typically about 500 times the cosmic mean total density, and the temperature is typically 1-2 times 10^4 K, just above the Lyman alpha cooling floor. These findings argue that the hydrodynamic properties of the gas are more important than the dark matter in determining the structure. Filaments form a major pipeline for the transport of gas into the centers of galaxies. Since the temperature and ionization state of the gas completely determine the mass per unit length of an isothermal gas cylinder, our findings suggest a constraint upon gas transport into galaxies by this mechanism.

  6. Laser filamentation mathematical methods and models

    CERN Document Server

    Lorin, Emmanuel; Moloney, Jerome

    2016-01-01

    This book is focused on the nonlinear theoretical and mathematical problems associated with ultrafast intense laser pulse propagation in gases and in particular, in air. With the aim of understanding the physics of filamentation in gases, solids, the atmosphere, and even biological tissue, specialists in nonlinear optics and filamentation from both physics and mathematics attempt to rigorously derive and analyze relevant non-perturbative models. Modern laser technology allows the generation of ultrafast (few cycle) laser pulses, with intensities exceeding the internal electric field in atoms and molecules (E=5x109 V/cm or intensity I = 3.5 x 1016 Watts/cm2 ). The interaction of such pulses with atoms and molecules leads to new, highly nonlinear nonperturbative regimes, where new physical phenomena, such as High Harmonic Generation (HHG), occur, and from which the shortest (attosecond - the natural time scale of the electron) pulses have been created. One of the major experimental discoveries in this nonlinear...

  7. In situ ellipsometric study of surface immobilization of flagellar filaments

    Energy Technology Data Exchange (ETDEWEB)

    Kurunczi, S., E-mail: kurunczi@mfa.kfki.hu [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Nemeth, A.; Huelber, T. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Kozma, P. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Petrik, P. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Jankovics, H. [Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Sebestyen, A. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Vonderviszt, F. [Department of Photonics, Research Institute for Technical Physics and Materials Science, H-1121, Konkoly Thege Miklos ut 29-33, Budapest (Hungary); Department of Nanotechnology, Research Institute of Chemical and Process Engineering, Faculty of Information Technology, University of Pannonia, Egyetem u. 10, Veszprem, H-8200 (Hungary); Institute of Enzymology, Karolina ut 29-33, Budapest, H-1113 (Hungary); and others

    2010-10-15

    Protein filaments composed of thousands of subunits are promising candidates as sensing elements in biosensors. In this work in situ spectroscopic ellipsometry is applied to monitor the surface immobilization of flagellar filaments. This study is the first step towards the development of layers of filamentous receptors for sensor applications. Surface activation is performed using silanization and a subsequent glutaraldehyde crosslinking. Structure of the flagellar filament layers immobilized on activated and non-activated Si wafer substrates is determined using a two-layer effective medium model that accounted for the vertical density distribution of flagellar filaments with lengths of 300-1500 nm bound to the surface. The formation of the first interface layer can be explained by the multipoint covalent attachment of the filaments, while the second layer is mainly composed of tail pinned filaments floating upwards with the free parts. As confirmed by atomic force microscopy, covalent immobilization resulted in an increased surface density compared to absorption.

  8. COMPLEX FLARE DYNAMICS INITIATED BY A FILAMENT–FILAMENT INTERACTION

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Chunming; McAteer, R. T. James [Department of Astronomy, New Mexico State University, NM 88003 (United States); Liu, Rui [CAS Key Laboratory of Geospace Environment, Department of Geophysics and Planetary Sciences, University of Science and Technology of China, Hefei 230026 (China); Alexander, David [Department of Physics and Astronomy, Rice University, TX 77005 (United States); Sun, Xudong, E-mail: czhu@nmsu.edu [W. W. Hansen Experimental Physics Laboratory, Stanford University, Stanford, CA 94305 (United States)

    2015-11-01

    We report on an eruption involving a relatively rare filament–filament interaction on 2013 June 21, observed by SDO and STEREO-B. The two filaments were separated in height with a “double-decker” configuration. The eruption of the lower filament began simultaneously with a descent of the upper filament, resulting in a convergence and direct interaction of the two filaments. The interaction was accompanied by the heating of surrounding plasma and an apparent crossing of a loop-like structure through the upper filament. The subsequent coalescence of the filaments drove a bright front ahead of the erupting structures. The whole process was associated with a C3.0 flare followed immediately by an M2.9 flare. Shrinking loops and descending dark voids were observed during the M2.9 flare at different locations above a C-shaped flare arcade as part of the energy release, giving us unique insight into the flare dynamics.

  9. Topological Aspect of Knotted Vortex Filaments in Excitable Media

    Institute of Scientific and Technical Information of China (English)

    REN Ji-Rong; ZHU Tao; DUAN Yi-Shi

    2008-01-01

    Scroll waves exist ubiquitously in three-dimensional excitable media.The rotation centre can be regarded as a topological object called the vortex filament.In three-dimensional space,the vortex filaments usually form closed loops,and can be even linked and knotted.We give a rigorous topological description of knotted vortex filaments.By using the Φ-mapping topological current theory,we rewrite the topological current form of the charge density of vortex filaments,and using this topological current we reveal that the Hopf invariant of vortex filaments is just the sum of the linking and self-linking numbers of the knotted vortex filaments.We think that the precise expression of the Hopf invariant may imply a new topological constraint on knotted vortex filaments.

  10. The Dark Matter filament between Abell 222/223

    Science.gov (United States)

    Dietrich, Jörg P.; Werner, Norbert; Clowe, Douglas; Finoguenov, Alexis; Kitching, Tom; Miller, Lance; Simionescu, Aurora

    2016-10-01

    Weak lensing detections and measurements of filaments have been elusive for a long time. The reason is that the low density contrast of filaments generally pushes the weak lensing signal to unobservably low scales. To nevertheless map the dark matter in filaments exquisite data and unusual systems are necessary. SuprimeCam observations of the supercluster system Abell 222/223 provided the required combination of excellent seeing images and a fortuitous alignment of the filament with the line-of-sight. This boosted the lensing signal to a detectable level and led to the first weak lensing mass measurement of a large-scale structure filament. The filament connecting Abell 222 and Abell 223 is now the only one traced by the galaxy distribution, dark matter, and X-ray emission from the hottest phase of the warm-hot intergalactic medium. The combination of these data allows us to put the first constraints on the hot gas fraction in filaments.

  11. Application of a Mechanistic Model as a Tool for On-line Monitoring of Pilot Scale Filamentous Fungal Fermentation Processes - The Importance of Evaporation Effects

    DEFF Research Database (Denmark)

    Mears, Lisa; Stocks, Stuart M.; Albæk, Mads Orla

    2017-01-01

    A mechanistic model-based soft sensor is developed and validated for 550L filamentous fungus fermentations operated at Novozymes A/S. The soft sensor is comprised of a parameter estimation block based on a stoichiometric balance, coupled to a dynamic process model. The on-line parameter estimatio...... sensor at this scale, this allows for improved process monitoring, as well as opening up further possibilities for on-line control algorithms, utilizing these on-line model outputs. This article is protected by copyright. All rights reserved...

  12. [Elimination of microscopic filamentous fungi with disinfectants].

    Science.gov (United States)

    Laciaková, A; Laciak, V

    1994-01-01

    The antifungal effectivity of three single-component (Persteril, Septonex, Glutaraldehyd) and of three combined (Persteril+Septonex, Pesteril+Glutaraldehyd, Glutaraldehyd+Septonex) commercially available disinfectants was monitored by the diffuse method on five fen of the microscopic filamentous fungi Aspergillus alternata, Aspergillus niger, Mucor fragillis, Fusarium moniliforme, Penicillium glabrum. The highest antifungal activity was observed in 2% Persteril while 2% Persteril + 1% Septonex were the most effective among the combined disinfectants. M. fragilis was the most resistant strain.

  13. Cold Milky Way HI Gas in Filaments

    Science.gov (United States)

    Kalberla, P. M. W.; Kerp, J.; Haud, U.; Winkel, B.; Ben Bekhti, N.; Flöer, L.; Lenz, D.

    2016-04-01

    We investigate data from the Galactic Effelsberg-Bonn H i Survey, supplemented with data from the third release of the Galactic All Sky Survey (GASS III) observed at Parkes. We explore the all-sky distribution of the local Galactic H i gas with | {v}{{LSR}}| \\lt 25 km s-1 on angular scales of 11‧-16‧. Unsharp masking is applied to extract small-scale features. We find cold filaments that are aligned with polarized dust emission and conclude that the cold neutral medium (CNM) is mostly organized in sheets that are, because of projection effects, observed as filaments. These filaments are associated with dust ridges, aligned with the magnetic field measured on the structures by Planck at 353 GHz. The CNM above latitudes | b| \\gt 20^\\circ is described by a log-normal distribution, with a median Doppler temperature TD = 223 K, derived from observed line widths that include turbulent contributions. The median neutral hydrogen (H i) column density is NH i ≃ 1019.1 cm-2. These CNM structures are embedded within a warm neutral medium with NH i ≃ 1020 cm-2. Assuming an average distance of 100 pc, we derive for the CNM sheets a thickness of ≲0.3 pc. Adopting a magnetic field strength of Btot = (6.0 ± 1.8) μG, proposed by Heiles & Troland, and assuming that the CNM filaments are confined by magnetic pressure, we estimate a thickness of 0.09 pc. Correspondingly, the median volume density is in the range 14 ≲ n ≲ 47 cm-3. The authors thank the Deutsche Forschungsgemeinschaft (DFG) for support under grant numbers KE757/11-1, KE757/7-3, KE757/7-2, KE757/7-1, and BE4823/1-1.

  14. Formation of magnetic filaments: A kinetic study

    Science.gov (United States)

    Martínez-Pedrero, F.; Tirado-Miranda, M.; Schmitt, A.; Callejas-Fernández, J.

    2007-07-01

    In order to form magnetic filaments or chains, aqueous suspensions of superparamagnetic colloidal particles were aggregated under the action of an external magnetic field in the presence of different amounts of an indifferent 1:1 electrolyte (KBr). This allowed the influence of the anisotropic magnetic and isotropic electrostatic interactions on the aggregation behavior of these electric double-layered magnetic particles to be studied. Dynamic light scattering was used for monitoring the average diffusion coefficient of the magnetic filaments formed. Hydrodynamic equations were employed for obtaining the average chain lengths from the experimental mean diffusion coefficients. The results show that, for the same exposure time to the magnetic field, the average filament size is monotonously related to the amount of electrolyte added. The chain growth behavior was found to follow a power law with a similar exponent for all electrolyte concentrations used in this work. The time evolution of the average filament size can be rescaled such that all the curves collapse on a single master curve. Since the electrolyte added does not have any effect on the scaling behavior, the mechanism of aggregation seems to be completely controlled by the dipolar interaction. However, electrolyte addition not only controls the range of the total interaction between the particles, but also enhances the growth rate of the aggregation process. Taking into account the anisotropic character of these aggregation processes we propose a kernel that depends explicitly on the range of the dipolar interaction. The corresponding solutions of the Smoluchowski equation combined with theoretical models for the diffusion and light scattering by rigid rods reproduce the measured time evolution of the average perpendicular aggregate diffusion coefficient quite satisfactorily.

  15. Simple and convenient method for culturing anaerobic bacteria.

    OpenAIRE

    Behbehani, M J; Jordan, H. V.; Santoro, D L

    1982-01-01

    A simple and convenient method for culturing anaerobic bacteria is described. Cultures can be grown in commercially available flasks normally used for preparation of sterile external solutions. A special disposable rubber flask closure maintains anaerobic conditions in the flask after autoclaving. Growth of a variety of anaerobic oral bacteria was comparable to that obtained after anaerobic incubation of broth cultures in Brewer Anaerobic Jars.

  16. Mechanical Properties of Intermediate Filament Proteins.

    Science.gov (United States)

    Charrier, Elisabeth E; Janmey, Paul A

    2016-01-01

    Purified intermediate filament (IF) proteins can be reassembled in vitro to produce polymers closely resembling those found in cells, and these filaments form viscoelastic gels. The cross-links holding IFs together in the network include specific bonds between polypeptides extending from the filament surface and ionic interactions mediated by divalent cations. IF networks exhibit striking nonlinear elasticity with stiffness, as quantified by shear modulus, increasing an order of magnitude as the networks are deformed to large strains resembling those that soft tissues undergo in vivo. Individual IFs can be stretched to more than two or three times their resting length without breaking. At least 10 different rheometric methods have been used to quantify the viscoelasticity of IF networks over a wide range of timescales and strain magnitudes. The mechanical roles of different classes of cytoplasmic IFs on mesenchymal and epithelial cells in culture have also been studied by an even wider range of microrheological methods. These studies have documented the effects on cell mechanics when IFs are genetically or pharmacologically disrupted or when normal or mutant IF proteins are exogenously expressed in cells. Consistent with in vitro rheology, the mechanical role of IFs is more apparent as cells are subjected to larger and more frequent deformations.

  17. Oscillating Filaments. I. Oscillation and Geometrical Fragmentation

    Science.gov (United States)

    Gritschneder, Matthias; Heigl, Stefan; Burkert, Andreas

    2017-01-01

    We study the stability of filaments in equilibrium between gravity and internal as well as external pressure using the grid-based AMR code RAMSES. A homogeneous, straight cylinder below a critical line mass is marginally stable. However, if the cylinder is bent, such as with a slight sinusoidal perturbation, an otherwise stable configuration starts to oscillate, is triggered into fragmentation, and collapses. This previously unstudied behavior allows a filament to fragment at any given scale, as long as it has slight bends. We call this process “geometrical fragmentation.” In our realization, the spacing between the cores matches the wavelength of the sinusoidal perturbation, whereas up to now, filaments were thought to be only fragmenting on the characteristic scale set by the mass-to-line ratio. Using first principles, we derive the oscillation period as well as the collapse timescale analytically. To enable a direct comparison with observations, we study the line-of-sight velocity for different inclinations. We show that the overall oscillation pattern can hide the infall signature of cores.

  18. Modelling the chemistry of star forming filaments

    CERN Document Server

    Seifried, D

    2015-01-01

    We present simulations of star forming filaments incorporating - to our knowledge - the largest chemical network used to date on-the-fly in a 3D-MHD simulation. The network contains 37 chemical species and about 300 selected reaction rates. For this we use the newly developed package KROME (Grassi et al. 2014). We combine the KROME package with an algorithm which allows us to calculate the column density and attenuation of the interstellar radiation field necessary to properly model heating and ionisation rates. Our results demonstrate the feasibility of using such a complex chemical network in 3D-MHD simulations on modern supercomputers. We perform simulations with different strengths of the interstellar radiation field and the cosmic ray ionisation rate. We find that towards the centre of the filaments there is gradual conversion of hydrogen from H^+ over H to H_2 as well as of C^+ over C to CO. Moreover, we find a decrease of the dust temperature towards the centre of the filaments in agreement with recent...

  19. The tidal filament of NGC 4660

    CERN Document Server

    Kemp, S N; Marquez-Lugo, R A; Zepeda-Garcia, D; Franco-Hernandez, R; Nigoche-Netro, A; Ramos-Larios, G; Navarro, S G; Corral, L J

    2016-01-01

    NGC 4660, in the Virgo cluster, is a well-studied elliptical galaxy which has a strong disk component (D/T about 0.2-0.3). The central regions including the disk component have stellar populations with ages about 12-13 Gyr from SAURON studies. However we report the discovery of a long narrow tidal filament associated with the galaxy in deep co-added Schmidt plate images and deep CCD frames, implying that the galaxy has undergone a tidal interaction and merger within the last few Gyr. The relative narrowness of the filament implies a wet merger with at least one spiral galaxy involved, but the current state of the system has little evidence for this. However a 2-component photometric fit using GALFIT shows much bluer B-V colours for the disk component than for the elliptical component, which may represent a residual trace of enhanced star formation in the disk caused by the interaction 1-2 Gyr ago. There are brighter concentrations within the filament which resemble Tidal Dwarf Galaxies, although they are at l...

  20. Genome and physiology of the ascomycete filamentous fungus Xeromyces bisporus, the most xerophilic organism isolated to date

    DEFF Research Database (Denmark)

    Leong, Su-lin L.; Lantz, Henrik; Pettersson, Olga V.

    2015-01-01

    Xeromyces bisporus can grow on sugary substrates down to 0.61, an extremely low water activity. Its genome size is approximately 22 Mb. Gene clusters encoding for secondary metabolites were conspicuously absent; secondary metabolites were not detected experimentally. Thus, in its 'dry' but nutrie...

  1. Characterization of a mutant strain of a filamentous fungus Cladosporium phlei for the mass production of the secondary metabolite phleichrome.

    Science.gov (United States)

    Yi, Min-Hee; Kim, Jung-Ae; Kim, Jung-Mi; Park, Jin-Ah; Kim, Beom-Tae; Park, Seung-Moon; Yang, Moon-Sik; Hwang, Ki-Jun; Kim, Dae-Hyuk

    2011-08-01

    UV-mutagenesis was performed to obtain mutant strains that demonstrate altered production of phleichrome, a secondary metabolite of Cladosporium phlei. Among fifty mutants selected, based on the increased area and intensity of the purple pigment surrounding the colonies, the strain M0035 showed the highest production of phleichrome, more than seven fold over wild type. Plate cultures of the M0035 strain resulted in a total of 592 mg phleichrome consisting of 146 mg and 446 mg from the mycelia and agar media, respectively. The M0035 strain displayed a growth rate and a mycelial mass comparable to the parental strain but had significantly reduced asexual sporulation.

  2. Transient disruption of non-homologous end-joining facilitates targeted genome manipulations in the filamentous fungus Aspergillus nidulans

    DEFF Research Database (Denmark)

    Nielsen, Jakob Blæsbjerg; Nielsen, Michael Lynge; Mortensen, Uffe Hasbro

    2008-01-01

    We have developed a transiently disrupted nkuA system in Aspergillus nidulans for efficient gene targeting. The nkuA disruption was made by inserting a counter-selectable marker flanked by a direct repeat (DR) composed of nkuA sequences. In the disrupted state, the non-homologous end-joining (NHE...

  3. Bioconversion of waste office paper to gluconic acid in a turbine blade reactor by the filamentous fungus Aspergillus niger.

    Science.gov (United States)

    Ikeda, Yuko; Park, Enock Y; Okuda, Naoyuki

    2006-05-01

    Gluconic acid production was investigated using an enzymatic hydrolysate of waste office automation paper in a culture of Aspergillus niger. In repeated batch cultures using flasks, saccharified solution medium (SM) did not show any inhibitory effects on gluconic acid production compared to glucose medium (GM). The average gluconic acid yields were 92% (SM) and 80% (GM). In repeated batch cultures using SM in a turbine blade reactor (TBR), the gluconic acid yields were 60% (SM) and 67% (GM) with 80-100 g/l of gluconic acid. When pure oxygen was supplied the production rate increased to four times higher than when supplying air. Remarkable differences in the morphology of A. niger and dry cell weight between SM and GM were observed. The difference in morphology may have caused a reduction of oxygen transfer, resulting in a decrease in gluconic acid production rate in SM.

  4. Complete Genome Sequence of the Filamentous Fungus Aspergillus westerdijkiae Reveals the Putative Biosynthetic Gene Cluster of Ochratoxin A

    Science.gov (United States)

    Chakrabortti, Alolika; Li, Jinming

    2016-01-01

    Ochratoxin A (OTA) is a common mycotoxin that contaminates food and agricultural products. Sequencing of the complete genome of Aspergillus westerdijkiae, a major producer of OTA, reveals more than 50 biosynthetic gene clusters, including a putative OTA biosynthetic gene cluster that encodes a dozen of enzymes, transporters, and regulatory proteins. PMID:27635003

  5. Molecular ecology of anaerobic reactor systems

    DEFF Research Database (Denmark)

    Hofman-Bang, H. Jacob Peider; Zheng, D.; Westermann, Peter;

    2003-01-01

    Anaerobic reactor systems are essential for the treatment of solid and liquid wastes and constitute a core facility in many waste treatment plants. Although much is known about the basic metabolism in different types of anaerobic reactors, little is known about the microbes responsible...... to the abundance of each microbe in anaerobic reactor systems by rRNA probing. This chapter focuses on various molecular techniques employed and problems encountered when elucidating the microbial ecology of anaerobic reactor systems. Methods such as quantitative dot blot/fluorescence in-situ probing using various...

  6. Evaluation of a prereduced anaerobically sterilized medium (PRAS II) system for identification anaerobic microorganisms.

    Science.gov (United States)

    Beaucage, C M; Onderdonk, A B

    1982-09-01

    A prereduced, anaerobically sterilized system of tubed media (PRAS II; Scott Laboratories, Fiskeville, R.I.) was evaluated for accuracy in the identification of anerobic microorganisms. PRAS II was found to be a rapid and accurate identification system for obligate anaerobes which does not require the use of gas cannula inoculation or incubation in a special anaerobic environment.

  7. Evaluation of a prereduced anaerobically sterilized medium (PRAS II) system for identification anaerobic microorganisms.

    OpenAIRE

    Beaucage, C M; Onderdonk, A B

    1982-01-01

    A prereduced, anaerobically sterilized system of tubed media (PRAS II; Scott Laboratories, Fiskeville, R.I.) was evaluated for accuracy in the identification of anerobic microorganisms. PRAS II was found to be a rapid and accurate identification system for obligate anaerobes which does not require the use of gas cannula inoculation or incubation in a special anaerobic environment.

  8. Development of microorganisms during storage of wet brewery waste under aerobic and anaerobic conditions

    Directory of Open Access Journals (Sweden)

    Leiliane Cristine de Souza

    2012-01-01

    Full Text Available This research study was conducted to evaluate, by means of microbiological analyses, the preservation of wet brewery waste stored under aerobic and anaerobic conditions, regarding the development of filamentous fungi, yeasts and lactic-acid bacteria. The following treatments were used: untreated brewery waste, pre-dried brewery waste silage, brewery waste silage with effluent drainage and BW silage without effluent drainage. Silos made of PVC and equipped with Bunsen valves to allow gases to escape were used. Dry matter (DM, crude protein (CP, temperature (°C and pH in the untreated BW, in the stored brewery waste and in the brewery waste silage upon silo opening, after 60 days of ensilage were analyzed. A completely randomized design was used. The data were subjected to analysis of variance, and the means were compared by the Tukey test at the 5% probability level. The preservation of brewery waste packaged under aerobic conditions was not appropriate due to the development of filamentous fungi and yeasts; however, storage under anaerobic conditions proved to be an effective conservation process.

  9. Tropomyosin - master regulator of actin filament function in the cytoskeleton.

    Science.gov (United States)

    Gunning, Peter W; Hardeman, Edna C; Lappalainen, Pekka; Mulvihill, Daniel P

    2015-08-15

    Tropomyosin (Tpm) isoforms are the master regulators of the functions of individual actin filaments in fungi and metazoans. Tpms are coiled-coil parallel dimers that form a head-to-tail polymer along the length of actin filaments. Yeast only has two Tpm isoforms, whereas mammals have over 40. Each cytoskeletal actin filament contains a homopolymer of Tpm homodimers, resulting in a filament of uniform Tpm composition along its length. Evidence for this 'master regulator' role is based on four core sets of observation. First, spatially and functionally distinct actin filaments contain different Tpm isoforms, and recent data suggest that members of the formin family of actin filament nucleators can specify which Tpm isoform is added to the growing actin filament. Second, Tpms regulate whole-organism physiology in terms of morphogenesis, cell proliferation, vesicle trafficking, biomechanics, glucose metabolism and organ size in an isoform-specific manner. Third, Tpms achieve these functional outputs by regulating the interaction of actin filaments with myosin motors and actin-binding proteins in an isoform-specific manner. Last, the assembly of complex structures, such as stress fibers and podosomes involves the collaboration of multiple types of actin filament specified by their Tpm composition. This allows the cell to specify actin filament function in time and space by simply specifying their Tpm isoform composition.

  10. Degradation of thin tungsten filaments at high temperature in HWCVD

    Energy Technology Data Exchange (ETDEWEB)

    Frigeri, P.A., E-mail: pfrigeri@phys.ethz.ch; Nos, O.; Bertomeu, J.

    2015-01-30

    The degradation of the filaments is usually studied by checking the silicidation or carbonization status of the refractory metal used as catalysts, and their effects on the structural stability of the filaments. In this paper, it will be shown that the catalytic stability of a filament heated at high temperature is much shorter than its structural lifetime. The electrical resistance of a thin tungsten filament and the deposition rate of the deposited thin film have been monitored during the filament aging. It has been found that the deposition rate drops drastically once the quantity of dissolved silicon in the tungsten reaches the solubility limit and the silicides start precipitating. This manuscript concludes that the catalytic stability is only guaranteed for a short time and that for sufficiently thick filaments it does not depend on the filament radius. - Highlights: • A model for the electrical resistance of a tungsten filament during aging is presented. • Catalytic activity of the filament drops when W5Si3 precipitation takes place at its surface. • The catalytic stability of the filament does not depend on its radius in most practical situations.

  11. Patterns of molecular motors that guide and sort filaments.

    Science.gov (United States)

    Rupp, Beat; Nédélec, François

    2012-11-21

    Molecular motors can be immobilized to transport filaments and loads that are attached to these filaments inside a nano-device. However, if motors are distributed uniformly over a flat surface, the motility is undirected, and the filaments move equally in all directions. For many applications it is important to control the direction in which the filaments move, and two strategies have been explored to achieve this: applying external forces and confining the filaments inside channels. In this article, we discuss a third strategy in which the topography of the sample remains flat, but the motors are distributed non-uniformly over the surface. Systems of filaments and patterned molecular motors were simulated using a stochastic engine that included Brownian motion and filament bending elasticity. Using an evolutionary algorithm, patterns were optimized for their capacity to precisely control the paths of the filaments. We identified patterns of motors that could either direct the filaments in a particular direction, or separate short and long filaments. These functionalities already exceed what has been achieved with confinement. The patterns are composed of one or two types of motors positioned in lines or along arcs and should be easy to manufacture. Finally, these patterns can be easily combined into larger designs, allowing one to precisely control the motion of microscopic objects inside a device.

  12. Chemical composition of metapleural gland secretions of fungus-growing and non-fungus-growing ants.

    Science.gov (United States)

    Vieira, Alexsandro S; Morgan, E David; Drijfhout, Falko P; Camargo-Mathias, Maria I

    2012-10-01

    The metapleural gland is exclusive to ants, and unusual among exocrine glands in having no mechanism for closure and retention of secretion. As yet, no clear conclusion has been reached as to the function of metapleural gland secretion. Metapleural gland secretions were investigated for fungus-growing ants representing the derived attines Trachymyrmex fuscus, Atta laevigata, and Acromyrmex coronatus, the basal attines Apterostigma pilosum and Mycetarotes parallelus, and non-fungus-growing ants of the tribes Ectatommini (Ectatomma brunneum) and Myrmicini (Pogonomyrmex naegeli). Our results showed that the secretions of leaf-cutting ants (A. laevigata and A. coronatus) and the derived attine, T. fuscus, contain a greater variety and larger quantities of volatile compounds than those of myrmicine and ectatommine ants. The most abundant compounds found in the metapleural glands of A. laevigata and A. coronatus were hydroxyacids, and phenylacetic acid (only in A. laevigata). Indole was present in all groups examined, while skatole was found in large quantities only in attines. Ketones and aldehydes are present in the secretion of some attines. Esters are present in the metapleural gland secretion of all species examined, although mainly in A. laevigata, A. coronatus, and T. fuscus. Compared with basal attines and non-fungus-growing ants, the metapleural glands of leaf-cutting ants produce more acidic compounds that may have an antibiotic or antifungal function.

  13. SYSTEMIC INFECTION AND RELATED FUNGUS: AN OVERVIEW

    Directory of Open Access Journals (Sweden)

    Saha Rajsekhar

    2011-06-01

    Full Text Available A fungus is a member of a large group of eukaryotic organisms that includes microorganisms such as yeasts and molds (British English: moulds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, Fungi, which are separate from plants, animals, and bacteria. One major difference is that fungal cells have cell walls that contain chitin, unlike the cell walls of plants, which contain cellulose. Many fungi play a crucial role in decomposition (breaking things down and returning nutrients to the soil. They are also used in medicine, an example is the antibiotic penicillin, as well as in industry and food preparation. In the present time the microbes are to be seen as disease causing organisms harming the mankind. The harm done by this community cannot be taken lightly as they are also useful in many ways. The above article is an effort to bring out the various fungal issued related to human.

  14. Bioactive Triterpenes from the Fungus Piptoporus betulinus

    Directory of Open Access Journals (Sweden)

    Zeyad Alresly

    2016-01-01

    Full Text Available Phytochemical investigation of the ethyl acetate extract of the fruiting bodies from the basidiomycete Piptoporus betulinus led to the isolation of a new bioactive lanostane triterpene identified as 3 b -acetoxy-16-hydroxy-24-oxo-5α-lanosta-8- ene-21-oic acid (1. In addition, ten known triterpenes, polyporenic acid A (5, polyporenic acid C (4, three derivatives of polyporenic acid A (8, 10, 11, betulinic acid (3, betulin (2, ergosterol peroxide (6, 9,11-dehydroergosterol peroxide (7, and fomefficinic acid (9, were also isolated from the fungus. All isolated compounds were tested for antimicrobial activity against some Gram-positive and Gram-negative bacteria as well as against a fungal strain. The new triterpene and some of the other compounds showed antimicrobial activity against Gram-positive bacteria.

  15. Extracellular ATP activates MAPK and ROS signaling during injury response in the fungus Trichoderma atroviride

    Directory of Open Access Journals (Sweden)

    Elizabeth eMedina-Castellanos

    2014-11-01

    Full Text Available The response to mechanical damage is crucial for the survival of multicellular organisms, enabling their adaptation to hostile environments. Trichoderma atroviride, a filamentous fungus of great importance in the biological control of plant diseases, responds to mechanical damage by activating regenerative processes and asexual reproduction (conidiation. During this response, reactive oxygen species (ROS are produced by the NADPH oxidase (Nox1/NoxR complex. To understand the underlying early signaling events, we evaluated molecules such as extracellular ATP (eATP and Ca2+ that are known to trigger wound-induced responses in plants and animals. Concretely, we investigated the activation of mitogen-activated protein kinase (MAPK pathways by eATP, Ca2+ and ROS. Indeed, application of exogenous ATP and Ca2+ triggered conidiation. Furthermore, eATP promoted the Nox1-dependent production of ROS and activated a MAPK pathway. Mutants in the MAPK-encoding genes tmk1 and tmk3 were affected in wound-induced conidiation, and phosphorylation of both Tmk1 and Tmk3 was triggered by eATP. We conclude that in this fungus, eATP acts as a damage-associated molecular pattern (DAMP. Our data indicate the existence of an eATP receptor and suggest that in fungi, eATP triggers pathways that converge to regulate asexual reproduction genes that are required for injury-induced conidiation. By contrast, Ca2+ is more likely to act as a downstream second messenger. The early steps of mechanical damage response in T. atroviride share conserved elements with those known from plants and animals.

  16. An injury-response mechanism conserved across kingdoms determines entry of the fungus Trichoderma atroviride into development.

    Science.gov (United States)

    Hernández-Oñate, Miguel A; Esquivel-Naranjo, Edgardo U; Mendoza-Mendoza, Artemio; Stewart, Alison; Herrera-Estrella, Alfredo H

    2012-09-11

    A conserved injury-defense mechanism is present in plants and animals, in which the production of reactive oxygen species (ROS) and lipid metabolism are essential to the response. Here, we describe that in the filamentous fungus Trichoderma atroviride, injury results in the formation of asexual reproduction structures restricted to regenerating cells. High-throughput RNA-seq analyses of the response to injury in T. atroviride suggested an oxidative response and activation of calcium-signaling pathways, as well as the participation of lipid metabolism, in this phenomenon. Gene-replacement experiments demonstrated that injury triggers NADPH oxidase (Nox)-dependent ROS production and that Nox1 and NoxR are essential for asexual development in response to damage. We further provide evidence of H(2)O(2) and oxylipin production that, as in plants and animals, may act as signal molecules in response to injury in fungi, suggesting that the three kingdoms share a conserved defense-response mechanism.

  17. Comparative studies of the secretome of fungus-growing ants

    DEFF Research Database (Denmark)

    Linde, Tore; Grell, Morten Nedergaard; Schiøtt, Morten;

    2009-01-01

    Leafcutter ants of the species Acromyrmex echinatior live in symbiosis with the fungus Leucoagaricus gongylophorus. The ants harvest fragments of leaves and carry them to the nest where they place the material on the fungal colony. The fungus secretes a wide array of proteins to degrade the leaves...... into nutrients that the ants can feed on. The focus of this study is to discover, characterize and compare the secreted proteins. In order to do so cDNA libraries are constructed from mRNA extracted from the fungus material. The most efficient technology to screen cDNA libraries selectively for secreted...

  18. Genomic and in situ investigations of the novel uncultured Chloroflexi associated with 0092 morphotype filamentous bulking in activated sludge.

    Science.gov (United States)

    McIlroy, Simon Jon; Karst, Søren Michael; Nierychlo, Marta; Dueholm, Morten Simonsen; Albertsen, Mads; Kirkegaard, Rasmus Hansen; Seviour, Robert James; Nielsen, Per Halkjær

    2016-09-01

    Overgrowth of filamentous bacteria in activated sludge wastewater treatment plants (WWTPs) leads to impaired sludge settleability, a condition known as bulking, which is a common operational problem worldwide. Filaments with the Eikelboom 0092 morphotype are commonly associated with such bulking episodes. Members of the uncultured B45 phylotype, which is embraced within the phylum Chloroflexi, were recently shown to exhibit this morphology. Although these organisms are among the most abundant populations recorded in activated sludge processes, nothing is known about their metabolic characteristics. In this study, a genome sequence, representing the B45 phylotype, was retrieved from a metagenome generated from an activated sludge WWTP. The genome consisted of two chromosomes and one plasmid, which were 4.0, 1.0 and 0.04 Mbps in size, respectively. A metabolic model was constructed for this organism, based on annotation of its genome, showing its ability to generate energy by respiration, utilizing oxygen, nitrite or nitrous oxide as electron acceptors, or by fermentation of sugars. The ability of B45 members to ferment sugars under anaerobic conditions was validated in situ with microautoradiography-fluorescence in situ hybridization. The provisional name of 'Candidatus Promineofilum breve' is proposed for this species. This study represents the first detailed information on an uncultured genus of filamentous organisms from activated sludge.

  19. Filament Eruptions, Jets, and Space Weather

    Science.gov (United States)

    Moore, Ronald; Sterling, Alphonse; Robe, Nick; Falconer, David; Cirtain, Jonathan

    2013-01-01

    Previously, from chromospheric H alpha and coronal X-ray movies of the Sun's polar coronal holes, it was found that nearly all coronal jets (greater than 90%) are one or the other of two roughly equally common different kinds, different in how they erupt: standard jets and blowout jets (Yamauchi et al 2004, Apl, 605, 5ll: Moore et all 2010, Apj, 720, 757). Here, from inspection of SDO/AIA He II 304 A movies of 54 polar x-ray jets observed in Hinode/XRT movies, we report, as Moore et al (2010) anticipated, that (1) most standard x-ray jets (greater than 80%) show no ejected plasma that is cool enough (T is less than or approximately 10(exp 5K) to be seen in the He II 304 A movies; (2) nearly all blownout X-ray jets (greater than 90%) show obvious ejection of such cool plasma; (3) whereas when cool plasma is ejected in standard X-ray jets, it shows no lateral expansion, the cool plasma ejected in blowout X-ray jets shows strong lateral expansion; and (4) in many blowout X-ray jets, the cool plasma ejection displays the erupting-magnetic-rope form of clasic filament eruptions and is thereby seen to be a miniature filament eruption. The XRT movies also showed most blowout X-ray jets to be larger and brighter, and hence to apparently have more energy, than most standard X-ray jets. These observations (1) confirm the dichotomy of coronal jets, (2) agree with the Shibata model for standard jets, and (3) support the conclusion of Moore et al (2010) that in blowout jets the magnetic-arch base of the jet erupts in the manner of the much larger magnetic arcades in which the core field, the field rooted along the arcade's polarity inversion line, is sheared and twisted (sigmoid), often carries a cool-plasma filament, and erupts to blowout the arcade, producing a CME. From Hinode/SOT Ca II movies of the polar limb, Sterling et al (2010, ApJ, 714, L1) found that chromospheric Type-II spicules show a dichotomy of eruption dynamics similar to that found here for the cool

  20. Heterocyst placement strategies to maximize growth of cyanobacterial filaments

    CERN Document Server

    Brown, Aidan I

    2012-01-01

    Under conditions of limited fixed-nitrogen, some filamentous cyanobacteria develop a regular pattern of heterocyst cells that fix nitrogen for the remaining vegetative cells. We examine three different heterocyst placement strategies by quantitatively modelling filament growth while varying both external fixed-nitrogen and leakage from the filament. We find that there is an optimum heterocyst frequency which maximizes the growth rate of the filament; the optimum frequency decreases as the external fixed-nitrogen concentration increases but increases as the leakage increases. In the presence of leakage, filaments implementing a local heterocyst placement strategy grow significantly faster than filaments implementing random heterocyst placement strategies. With no extracellular fixed-nitrogen, consistent with recent experimental studies of Anabaena sp. PCC 7120, the modelled heterocyst spacing distribution using our local heterocyst placement strategy is qualitatively similar to experimentally observed patterns...

  1. Semiflexible biopolymers: Microrheology and single filament condensation

    Science.gov (United States)

    Schnurr, Bernhard

    Polymers and their elementary subunits, called monomers, come in an immense variety of structures and sizes, and are of great importance for their material properties as well as a multitude of biological functions. The emphasis here is on semiflexible polymers, which are identified by their intermediate degree of stiffness. Their individual as well as their collective properties when assembled into entangled networks is a topic of great interest to polymer physics, materials science, and biology. Some of the most important semiflexible polymers are biopolymers, with such prominent examples as DNA, F-actin, and microtubules. Their functions range from their use as structural elements in the cytoskeleton of most plant and animal cells, to their role as transport tracks for molecular motors, and the storage of genetic information in their linear sequence. The two parts of this experimental and theoretical thesis address single filament aspects as well as network properties of solutions of semiflexible polymers. In the first part, we describe an optical technique for measuring the bulk properties of soft materials at the local scale. We apply it to a solution of entangled, filamentous actin, a particularly difficult material to characterize with conventional techniques. Beyond a description of measurements and apparatus, we also discuss, from a theoretical point of view, the interpretation and fundamental limitations of this and other microrheological techniques. In the second part, we describe the condensation dynamics of a single, semiflexible filament, induced by changing solvent conditions. A biologically important example of this phenomenon is the condensation of DNA into toroidal structures, which occurs, for instance, in viral capsids. Our observations of a molecular simulation motivate an unexpected pathway of collapse via a series of metastable intermediates we call ``racquet'' states. The analysis of the conformational energies of these structures in the

  2. Langmuir wave filamentation in the kinetic regime

    CERN Document Server

    Silantyev, Denis A; Rose, Harvey A

    2016-01-01

    Nonlinear Langmuir wave in the kinetic regime $k\\lambda_D\\gtrsim0.2$ has a transverse instability, where $k$ is the wavenumber and $\\lambda_D$ is the Debye length. The nonlinear stage of that instability development leads to the filamentation of Langmuir waves. Here we study the linear stage of transverse instability of both Bernstein-Greene-Kruskal (BGK) modes and dynamically prepared BGK-like initial conditions to find the same instability growth rate suggesting the universal mechanism for the kinetic saturation of stimulated Raman scatter in laser-plasma interaction experiments. Multidimensional Vlasov simulations results are compared to the theoretical predictions.

  3. Filament winding cylinders. I - Process model

    Science.gov (United States)

    Lee, Soo-Yong; Springer, George S.

    1990-01-01

    A model was developed which describes the filament winding process of composite cylinders. The model relates the significant process variables such as winding speed, fiber tension, and applied temperature to the thermal, chemical and mechanical behavior of the composite cylinder and the mandrel. Based on the model, a user friendly code was written which can be used to calculate (1) the temperature in the cylinder and the mandrel, (2) the degree of cure and viscosity in the cylinder, (3) the fiber tensions and fiber positions, (4) the stresses and strains in the cylinder and in the mandrel, and (5) the void diameters in the cylinder.

  4. Hamiltonian Dynamics of Protein Filament Formation.

    Science.gov (United States)

    Michaels, Thomas C T; Cohen, Samuel I A; Vendruscolo, Michele; Dobson, Christopher M; Knowles, Tuomas P J

    2016-01-22

    We establish the Hamiltonian structure of the rate equations describing the formation of protein filaments. We then show that this formalism provides a unified view of the behavior of a range of biological self-assembling systems as diverse as actin, prions, and amyloidogenic polypeptides. We further demonstrate that the time-translation symmetry of the resulting Hamiltonian leads to previously unsuggested conservation laws that connect the number and mass concentrations of fibrils and allow linear growth phenomena to be equated with autocatalytic growth processes. We finally show how these results reveal simple rate laws that provide the basis for interpreting experimental data in terms of specific mechanisms controlling the proliferation of fibrils.

  5. Characterization of osmotically induced filaments of Salmonella enterica.

    Science.gov (United States)

    Pratt, Zachary L; Chen, Bingming; Czuprynski, Charles J; Wong, Amy C L; Kaspar, Charles W

    2012-09-01

    Salmonella enterica forms aseptate filaments with multiple nucleoids when cultured in hyperosmotic conditions. These osmotic-induced filaments are viable and form single colonies on agar plates even though they contain multiple genomes and have the potential to divide into multiple daughter cells. Introducing filaments that are formed during osmotic stress into culture conditions without additional humectants results in the formation of septa and their division into individual cells, which could present challenges to retrospective analyses of infectious dose and risk assessments. We sought to characterize the underlying mechanisms of osmotic-induced filament formation. The concentration of proteins and chromosomal DNA in filaments and control cells was similar when standardized by biomass. Furthermore, penicillin-binding proteins in the membrane of salmonellae were active in vitro. The activity of penicillin-binding protein 2 was greater in filaments than in control cells, suggesting that it may have a role in osmotic-induced filament formation. Filaments contained more ATP than did control cells in standardized cell suspensions, though the levels of two F(0)F(1)-ATP synthase subunits were reduced. Furthermore, filaments could septate and divide within 8 h in 0.2 × Luria-Bertani broth at 23°C, while nonfilamentous control cells did not replicate. Based upon the ability of filaments to septate and divide in this diluted broth, a method was developed to enumerate by plate count the number of individual, viable cells within a population of filaments. This method could aid in retrospective analyses of infectious dose of filamented salmonellae.

  6. Carbon monoxide conversion by anaerobic bioreactor sludges

    NARCIS (Netherlands)

    Sipma, J.; Stams, A.J.M.; Lens, P.N.L.; Lettinga, G.

    2003-01-01

    Seven different anaerobic sludges from wastewater treatment reactors were screened for their ability to convert carbon monoxide (CO) at 30 and 55degreesC
    Seven different anaerobic sludges from wastewater treatment reactors were screened for their ability to convert carbon monoxide (CO) at 30 and

  7. Anaerobic critical velocity in four swimming techniques.

    Science.gov (United States)

    Neiva, H P; Fernandes, R J; Vilas-Boas, J P

    2011-03-01

    The aim of this study was to assess critical velocity in order to control and evaluate anaerobic swimming training. 51 highly trained male swimmers performed maximal 15, 25, 37.5 and 50 m in the 4 swimming techniques to determine critical velocity from the distance-time relationship. Anaerobic critical velocity was compared with 100 m swimming performance and corresponding partials. Complementarily, 9 swimmers performed a 6×50 m (4 min interval) training series at front crawl individual anaerobic critical velocity, capillary blood lactate concentrations being assessed after each repetition. The mean±SD values of anaerobic critical velocity and its relationship with the 100 m event were: 1.61±0.07 (r=0.60, p=0.037), 1.53±0.05 (r=0.81, p=0.015), 1.33±0.05 (r=0.83, p=0.002), and 1.75±0.05 (r=0.74, p=0.001), for butterfly, backstroke, breaststroke and front crawl, respectively. However, differences between anaerobic critical velocity and performance were observed (with exception of the second half of the 100 m swimming events in breaststroke and butterfly). Lactate concentration values at the end of the series were 14.52±1.06 mmol.l (-1), which suggests that it was indeed an anaerobic training set. In this sense, anaerobic critical velocity can be used to prescribe anaerobic training intensities.

  8. Integrated anaerobic and aerobic treatment of sewage.

    NARCIS (Netherlands)

    Kaijun Wang,

    1994-01-01

    This thesis describes results of investigations dealing with sequential concept of anaerobic-aerobic treatment of municipal wastewater. The main purposes of the study were 1) to develop a proper anaerobic hydrolytic pretreatment unit, consisting of a Hydrolysis Upflow Sludge Bed (HUSB-) reactor and

  9. Anaerobic degradation of linear alkylbenzene sulfonate

    DEFF Research Database (Denmark)

    Mogensen, Anders Skibsted; Haagensen, Frank; Ahring, Birgitte Kiær

    2003-01-01

    increases during anaerobic stabilization due to transformation of easily degradable organic matter. Hence, LAS is regarded as resistant to biodegradation under anaerobic conditions. We present data from a lab-scale semi-continuously stirred tank reactor (CSTR) spiked with linear dodecylbenzene sulfonate (C...

  10. Plasma temperature clamping in filamentation laser induced breakdown spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Harilal, Sivanandan S.; Yeak, J.; Phillips, Mark C.

    2015-10-19

    Ultrafast laser filament induced breakdown spectroscopy is a very promising method for remote material detection. We present characteristics of plasmas generated in a metal target by laser filaments in air. Our measurements show that the temperature of the ablation plasma is clamped along the filamentation channel due to intensity clamping in a filament. Nevertheless, significant changes in radiation intensity are noticeable, and this is essentially due to variation in the number density of emitting atoms. The present results also partly explains the reason for the occurrence of atomic plume during fs LIBS in air compared to long-pulse ns LIBS.

  11. Controlling multiple filaments by relativistic optical vortex beams in plasmas

    Science.gov (United States)

    Ju, L. B.; Huang, T. W.; Xiao, K. D.; Wu, G. Z.; Yang, S. L.; Li, R.; Yang, Y. C.; Long, T. Y.; Zhang, H.; Wu, S. Z.; Qiao, B.; Ruan, S. C.; Zhou, C. T.

    2016-09-01

    Filamentation dynamics of relativistic optical vortex beams (OVBs) propagating in underdense plasma is investigated. It is shown that OVBs with finite orbital angular momentum (OAM) exhibit much more robust propagation behavior than the standard Gaussian beam. In fact, the growth rate of the azimuthal modulational instability decreases rapidly with increase of the OVB topological charge. Thus, relativistic OVBs can maintain their profiles for significantly longer distances in an underdense plasma before filamentation occurs. It is also found that an OVB would then break up into regular filament patterns due to conservation of the OAM, in contrast to a Gaussian laser beam, which in general experiences random filamentation.

  12. Plutonium ion emission from carburized rhenium mass spectrometer filaments

    Energy Technology Data Exchange (ETDEWEB)

    Kelley, J.M.; Robertson, D.M.

    1985-01-01

    Physicochemical processes important to the application of thermal emission mass spectrometry were identified and clarified. Effects of filament carbon concentration and temperature on plutonium ion emissions from a carburized rhenium filament were determined. Filament carbon concentration profoundly affected the appearance and duration of an ion signal. A useful ion signal was produced only when the carbon saturation temperature of the filament was exceeded, at which point first-order kinetics were either achieved or closely approached. This paper explains observed ion emission behavior in terms of pausible carbothermic reduction reactions and carbon diffusion processes that direct the course of those reactions. 31 references, 5 figures.

  13. Automated image analysis for quantification of filamentous bacteria

    DEFF Research Database (Denmark)

    Fredborg, M.; Rosenvinge, F. S.; Spillum, E.

    2015-01-01

    Background: Antibiotics of the beta-lactam group are able to alter the shape of the bacterial cell wall, e.g. filamentation or a spheroplast formation. Early determination of antimicrobial susceptibility may be complicated by filamentation of bacteria as this can be falsely interpreted as growth...... displaying different resistant profiles and differences in filamentation kinetics were used to study a novel image analysis algorithm to quantify length of bacteria and bacterial filamentation. A total of 12 beta-lactam antibiotics or beta-lactam-beta-lactamase inhibitor combinations were analyzed...

  14. Material Supply and Magnetic Configuration of an Active Region Filament

    Science.gov (United States)

    Zou, P.; Fang, C.; Chen, P. F.; Yang, K.; Hao, Q.; Cao, Wenda

    2016-11-01

    It is important to study the fine structures of solar filaments with high-resolution observations, since it can help us understand the magnetic and thermal structures of the filaments and their dynamics. In this paper, we study a newly formed filament located inside the active region NOAA 11762, which was observed by the 1.6 m New Solar Telescope at Big Bear Solar Observatory from 16:40:19 UT to 17:07:58 UT on 2013 June 5. As revealed by the Hα filtergrams, cool material is seen to be injected into the filament spine with a speed of 5-10 km s-1. At the source of the injection, brightenings are identified in the chromosphere, which are accompanied by magnetic cancellation in the photosphere, implying the importance of magnetic reconnection in replenishing the filament with plasmas from the lower atmosphere. Counter-streamings are detected near one endpoint of the filament, with the plane-of-the-sky speed being 7-9 km s-1 in the Hα red-wing filtergrams and 9-25 km s-1 in the blue-wing filtergrams. The observations are indicative that this active region filament is supported by a sheared arcade without magnetic dips, and the counter-streamings are due to unidirectional flows with alternative directions, rather than due to the longitudinal oscillations of filament threads as in many other filaments.

  15. Frenet algorithm for simulations of fluctuating continuous elastic filaments

    Science.gov (United States)

    Kats, Yevgeny; Kessler, David A.; Rabin, Yitzhak

    2002-02-01

    We present an algorithm for generating the equilibrium configurations of fluctuating continuous elastic filaments, based on a combination of statistical mechanics and differential geometry. We use this to calculate the distribution function of the end-to-end distance of filaments with nonvanishing spontaneous curvature and show that for small twist and large bending rigidities there is an intermediate temperature range in which the filament becomes nearly completely stretched. We show that volume interactions can be incorporated into our algorithm, demonstrating this through the calculation of the effect of excluded volume on the end-to-end distance of the filament.

  16. Formation and evolution of an active region filament

    CERN Document Server

    Kuckein, C; Pillet, V Martínez

    2013-01-01

    Several scenarios explaining how filaments are formed can be found in literature. In this paper, we analyzed the observations of an active region filament and critically evaluated the observed properties in the context of current filament formation models. This study is based on multi-height spectropolarimetric observations. The inferred vector magnetic field has been extrapolated starting either from the photosphere or from the chromosphere. The line-of-sight motions of the filament, which was located near disk center, have been analyzed inferring the Doppler velocities. We conclude that a part of the magnetic structure emerged from below the photosphere.

  17. Dynamics of Actin Filament Ends in a Network

    Science.gov (United States)

    Yang, Le; Sept, David; Carlsson, Anders

    2004-03-01

    The formation of filopodia-like bundles in vitro from a dendritic actin network has been observed(D. Vignjevic et al, J. Cell Biol. 160, 951 (2003)) to occur as a result of a nucleation process. We study the dynamics of the actin filament ends in such a network in order to evaluate the dynamics of the bundle nucleation process. Our model treats two semiflexible actin filaments fixed at one end and free at the other, moving according to Brownian dynamics. The initial filament positions are chosen according to a thermal distribution, and we evaluate the time for the filaments to come close enough to each other to interact and bind. The capture criterion is based either on the distance between filaments, or on a combination of distance and relative orientation. We evaluate the dependence of the capture time on the filament length and radius, and the distance between the filament bases. Since treating the movement of the individual monomers in filaments is computationally unwieldy, we treat the filament motion using a normal mode analysis which permits use of a much longer timestep. We find that this method yields rapid convergence even when only the few longest-wavelength modes are included.

  18. Prospects of Anaerobic Digestion Technology in China

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    As the world's largest developing country, China must face the problem of managing municipal solid waste, and the challenge of organic waste disposal is even more serious. Considering the characteristics of traditional waste disposal technologies and the subsequent secondary pollution, anaerobic digestion has various advantages such as reduction in the land needed for disposal and preservation of environmental quality. In light of the energy crisis, this paper focuses on the potential production of biogas from biowaste through anaerobic digestion processes, the problems incurred by the waste collection system, and the efficiency of the anaerobic digestion process. Use of biogas in a combined heat and power cogeneration system is also discussed. Finally, the advantages of anaerobic digestion technology for the Chinese market are summarized. The anaerobic digestion is suggested to be a promising treating technology for the organic wastes in China.

  19. Toxicants inhibiting anaerobic digestion: a review.

    Science.gov (United States)

    Chen, Jian Lin; Ortiz, Raphael; Steele, Terry W J; Stuckey, David C

    2014-12-01

    Anaerobic digestion is increasingly being used to treat wastes from many sources because of its manifold advantages over aerobic treatment, e.g. low sludge production and low energy requirements. However, anaerobic digestion is sensitive to toxicants, and a wide range of compounds can inhibit the process and cause upset or failure. Substantial research has been carried out over the years to identify specific inhibitors/toxicants, and their mechanism of toxicity in anaerobic digestion. In this review we present a detailed and critical summary of research on the inhibition of anaerobic processes by specific organic toxicants (e.g., chlorophenols, halogenated aliphatics and long chain fatty acids), inorganic toxicants (e.g., ammonia, sulfide and heavy metals) and in particular, nanomaterials, focusing on the mechanism of their inhibition/toxicity. A better understanding of the fundamental mechanisms behind inhibition/toxicity will enhance the wider application of anaerobic digestion.

  20. New Polyketides and New Benzoic Acid Derivatives from the Marine Sponge-Associated Fungus Neosartorya quadricincta KUFA 0081

    Directory of Open Access Journals (Sweden)

    Chadaporn Prompanya

    2016-07-01

    Full Text Available Two new pentaketides, including a new benzofuran-1-one derivative (1 and a new isochromen-1-one (5, and seven new benzoic acid derivatives, including two new benzopyran derivatives (2a, b, a new benzoxepine derivative (3, two new chromen-4-one derivatives (4b, 7 and two new benzofuran derivatives (6a, b, were isolated, together with the previously reported 2,3-dihydro-6-hydroxy-2,2-dimethyl-4H-1-benzopyran-4-one (4a, from the culture of the marine sponge-associated fungus Neosartorya quadricincta KUFA 0081. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and in the case of compounds 1, 2a, 4b, 5, 6a and 7, the absolute configurations of their stereogenic carbons were determined by an X-ray crystallographic analysis. None of the isolated compounds were active in the tests for antibacterial activity against Gram-positive and Gram-negative bacteria, as well as multidrug-resistant isolates from the environment (MIC > 256 μg/mL, antifungal activity against yeast (Candida albicans ATTC 10231, filamentous fungus (Aspergillus fumigatus ATTC 46645 and dermatophyte (Trichophyton rubrum FF5 (MIC > 512 µg/mL and in vitro growth inhibitory activity against the MCF-7 (breast adenocarcinoma, NCI-H460 (non-small cell lung cancer and A375-C5 (melanoma cell lines (GI50 > 150 µM by the protein binding dye SRB method.

  1. New Polyketides and New Benzoic Acid Derivatives from the Marine Sponge-Associated Fungus Neosartorya quadricincta KUFA 0081

    Science.gov (United States)

    Prompanya, Chadaporn; Dethoup, Tida; Gales, Luís; Lee, Michael; Pereira, José A. C.; Silva, Artur M. S.; Pinto, Madalena M. M.; Kijjoa, Anake

    2016-01-01

    Two new pentaketides, including a new benzofuran-1-one derivative (1) and a new isochromen-1-one (5), and seven new benzoic acid derivatives, including two new benzopyran derivatives (2a, b), a new benzoxepine derivative (3), two new chromen-4-one derivatives (4b, 7) and two new benzofuran derivatives (6a, b), were isolated, together with the previously reported 2,3-dihydro-6-hydroxy-2,2-dimethyl-4H-1-benzopyran-4-one (4a), from the culture of the marine sponge-associated fungus Neosartorya quadricincta KUFA 0081. The structures of the new compounds were established based on 1D and 2D NMR spectral analysis, and in the case of compounds 1, 2a, 4b, 5, 6a and 7, the absolute configurations of their stereogenic carbons were determined by an X-ray crystallographic analysis. None of the isolated compounds were active in the tests for antibacterial activity against Gram-positive and Gram-negative bacteria, as well as multidrug-resistant isolates from the environment (MIC > 256 μg/mL), antifungal activity against yeast (Candida albicans ATTC 10231), filamentous fungus (Aspergillus fumigatus ATTC 46645) and dermatophyte (Trichophyton rubrum FF5) (MIC > 512 µg/mL) and in vitro growth inhibitory activity against the MCF-7 (breast adenocarcinoma), NCI-H460 (non-small cell lung cancer) and A375-C5 (melanoma) cell lines (GI50 > 150 µM) by the protein binding dye SRB method. PMID:27438842

  2. The role of mites in insect-fungus associations.

    Science.gov (United States)

    Hofstetter, R W; Moser, J C

    2014-01-01

    The interactions among insects, mites, and fungi are diverse and complex but poorly understood in most cases. Associations among insects, mites, and fungi span an almost incomprehensible array of ecological interactions and evolutionary histories. Insects and mites often share habitats and resources and thus interact within communities. Many mites and insects rely on fungi for nutrients, and fungi benefit from them with regard to spore dispersal, habitat provision, or nutrient resources. Mites have important impacts on community dynamics, ecosystem processes, and biodiversity within many insect-fungus systems. Given that mites are understudied but highly abundant, they likely have bigger, more important, and more widespread impacts on communities than previously recognized. We describe mutualistic and antagonistic effects of mites on insect-fungus associations, explore the processes that underpin ecological and evolutionary patterns of these multipartite communities, review well-researched examples of the effects of mites on insect-fungus associations, and discuss approaches for studying mites within insect-fungus communities.

  3. Evolutionary patterns of proteinase activity in attine ant fungus gardens

    DEFF Research Database (Denmark)

    Semenova, Tatyana; Hughes, David Peter; Boomsma, Jacobus Jan;

    2011-01-01

    hypothesized that fungal proteinase activity may have been under selection for efficiency and that different classes of proteinases might be involved. Results: We determined proteinase activity profiles across a wide pH range for fungus gardens of 14 Panamanian species of fungus-growing ants, representing...... activities than the lower attine symbionts. Their total in vitro proteinase activity peaked at pH values around 5, which is close to the pH that the ants maintain in their fungus gardens, suggesting that the pH optimum of fungal proteinases may have changed after the irreversible domestication...... of evolutionary more derived fungal symbionts. This notion is also supported by buffering capacities of fungus gardens at pH 5.2 being remarkably high, and suggests that the fungal symbiont actively helps to maintain garden acidity at this specific level. Metalloproteinases dominated the activity profiles...

  4. An insect parasitoid carrying an ochratoxin producing fungus

    Science.gov (United States)

    Vega, Fernando E.; Posada, Francisco; Gianfagna, Thomas J.; Chaves, Fabio C.; Peterson, Stephen W.

    2006-06-01

    The insect parasitoid Prorops nasuta has been introduced from Africa to many coffee-producing countries in an attempt to control the coffee berry borer. In this paper, we report on the sequencing of the ITS LSU-rDNA and beta-tubulin loci used to identify a fungus isolated from the cuticle of a P. nasuta that emerged from coffee berries infected with the coffee berry borer. The sequences were compared with deposits in GenBank and the fungus was identified as Aspergillus westerdijkiae. The fungus tested positive for ochratoxin A production, with varying levels depending on the media in which it was grown. These results raise the possibility that an insect parasitoid might be disseminating an ochratoxin-producing fungus in coffee plantations.

  5. Biological active anthraquinone analogs from the fungus Eurotium sp.

    Digital Repository Service at National Institute of Oceanography (India)

    Parameswaran, P.S.; Gawas, D.; Tilvi, S.; Naik, C.G.

    Four known anthraquinones: Physcion, fluoroglaucin, catenarin and alaternin as well as a cyclic dipeptide with a triprenylated indole moiety, echinulin were purified from acetone extract of the mycelial mats of the fungus Eurotium sp. isolated from...

  6. Filamentous fungal endophthalmitis: results of combination therapy with intravitreal amphotericin B and voriconazole

    Directory of Open Access Journals (Sweden)

    Mithal K

    2015-04-01

    Full Text Available Kopal Mithal,1 Avinash Pathengay,1 Abhishek Bawdekar,1 Animesh Jindal,1 Divya Vira,2 Nidhi Relhan,3 Himadri Choudhury,1 Namrata Gupta,1 Varun Gupta,1 Nagendra K Koday,4 Harry W Flynn Jr3 1Retina and Uveitis Services, 2Cornea Services, LV Prasad Eye Institute, GMR Varalakshmi Campus, Visakhapatnam, India; 3Department of Ophthalmology, Bascom Palmer Eye Institute, University of Miami Miller School of Medicine, Miami, FL, USA; 4Ocular Microbiology Service, LV Prasad Eye Institute, GMR Varalakshmi Campus, Visakhapatnam, India Purpose: To report outcomes of exogenous fungal endophthalmitis treated with combination of intravitreal antifungal agents. Design: Retrospective, non-randomized, interventional, consecutive case series. Methods: Twelve eyes of twelve consecutive cases of filamentous fungal endophthalmitis were treated with a combination of intravitreal amphotericin-B and intravitreal voriconazole (AmB-Vo Regime along with pars plana vitrectomy at a single center. Clinical characteristics, microbiology results, treatment strategy, visual, and anatomical outcomes were analyzed. Results: Ten cases out of the twelve were postoperative endophthalmitis of which nine were part of a post cataract surgery cluster. The remaining included endophthalmitis following keratitis post pterygium excision (1 and following open globe injury (2. The most common fungus was Aspergillus terreus, which was isolated in 8/12, followed by A. flavus in 2/12 and Fusarium solani in 1/12. The presenting visual acuity ranged from light perception (LP to counting fingers. The visual acuity at final follow-up was 20/400 or better in 7/12 eyes (58.33% and 20/60 in 2/12 eyes (range 20/60 to LP. All eyes with corneal involvement had final visual acuity 20/400 or worse. Globe salvage was achieved in all cases. Conclusion: Combining intravitreal amphotericin-B and voriconazole could be a novel treatment strategy in the management of endophthalmitis caused by filamentous fungus. Eyes

  7. The Golgi apparatus: insights from filamentous fungi.

    Science.gov (United States)

    Pantazopoulou, Areti

    2016-01-01

    Cargo passage through the Golgi, albeit an undoubtedly essential cellular function, is a mechanistically unresolved and much debated process. Although the main molecular players are conserved, diversification of the Golgi among different eukaryotic lineages is providing us with tools to resolve standing controversies. During the past decade the Golgi apparatus of model filamentous fungi, mainly Aspergillus nidulans, has been intensively studied. Here an overview of the most important findings in the field is provided. Golgi architecture and dynamics, as well as the novel cell biology tools that were developed in filamentous fungi in these studies, are addressed. An emphasis is placed on the central role the Golgi has as a crossroads in the endocytic and secretory-traffic pathways in hyphae. Finally the major advances that the A. nidulans Golgi biology has yielded so far regarding our understanding of key Golgi regulators, such as the Rab GTPases RabC(Rab6) and RabE(Rab11), the oligomeric transport protein particle, TRAPPII, and the Golgi guanine nucleotide exchange factors of Arf1, GeaA(GBF1/Gea1) and HypB(BIG/Sec7), are highlighted.

  8. Filamentation and supercontinuum generation in lanthanum glass

    Science.gov (United States)

    Yang, Yuxia; Liao, Meisong; Li, Xia; Bi, Wanjun; Ohishi, Yasutake; Cheng, Tonglei; Fang, Yongzheng; Zhao, Guoying; Gao, Weiqing

    2017-01-01

    A broadband supercontinuum (SC) covering 400-2800 nm in a 20 dB dynamic range is reported in a piece of highly nonlinear, low-dispersion bulk lanthanum glass without employing any lens to focus the pump pulse. The spectrum width obtained in this study is broader than the maximum spectrum width obtained in silica photonic crystal fibers. The filaments and bright conical visible emission patterns of the SC are analyzed. Under optimum pump conditions, an SC conversion efficiency of 75% is obtained. The SC conversion efficiency is confirmed to be stable. Additionally, the relationship between the input peak intensity and the output beam radius is elucidated by simulating the propagation of a Gaussian beam in the bulk lanthanum glass. A 0.20 mm stable laser beam radius at the end of the propagation domain is demonstrated in a certain input peak intensity range. This small value of the beam radius indicates that most of the output power is localized over a small region because of the Kerr focusing effect despite the existence of conical emission in the SC generation by filamentation. The findings of this study are of significance for the development of ultra-broadband SC sources based on bulk glasses and high peak power lasers.

  9. Characterising Radio Emissions in Cosmic Filaments

    Science.gov (United States)

    Miller, R. O.

    2014-02-01

    A growing number of radio studies probe galaxy clusters into the low-power regime in which star formation is the dominant source of radio emission. However, at the time of writing no comparably deep observations have focused exclusively on the radio populations of cosmic filaments. This thesis describes the ATCA 2.1 GHz observations and subsequent analysis of two such regions - labelled Zone 1 (between clusters A3158 and A3125/A3128) and Zone 2 (between A3135 and A3145) - in the Horologium-Reticulum Supercluster (HRS). Source count profiles of both populations are discussed and a radio luminosity function for Zone 1 is generated. While the source counts of Zone 2 appear to be consistent with expected values, Zone 1 exhibits an excess of counts across a wide flux range (1 mJy< S_1.4 < 200 mJy). An excess in radio activity at the lower extent of this range (log P_1.4 < 22.5; within the SF-dominated regime) is also suggested by the radio luminosity function for that region, and brief colour analysis suggests that such an excess is indeed predominantly associated with a starforming population. The differences between the two filamentary zones is attributed to cosmic variation. The regions are both small (~ 1 degree square), and are significantly separated in the HRS. Further radio observations of filaments are required and the results combined into a larger sample size in order to arrive at a generalised model filamentary population.

  10. Laser filament-induced aerosol formation

    Directory of Open Access Journals (Sweden)

    H. Saathoff

    2012-11-01

    Full Text Available Using the aerosol and cloud simulation chamber AIDA we investigated the laser filament induced particle formation in ambient air, humid synthetic air, humid nitrogen, argon-oxygen mixture, and pure argon in order to simulate the particle formation under realistic atmospheric conditions as well as to investigate the influence of typical gas-phase atmospheric constituents on the particle formation. Terawatt laser plasma filaments generated new particles in the size range 3 to 130 nm with particle production rates ranging from 1 × 107 to 5 × 109 cm−3 plasma s−1. In all cases the particle formation rates increased exponentially with the water content of the gas mixture. Furthermore, the presence of a few ppb of trace gases like SO2 and α-pinene clearly enhanced the particle yield by number, the latter also by mass. Our findings suggest that new particle formation is efficiently supported by acids generated by the photo-ionization of both major and minor components of the air, including N2, NH3, SO2 and organics.

  11. Survey reveals the situation of Chinese caterpillar fungus resources

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    @@ Following its investigation of aweto (or Chinese caterpillar fungus) resources carried out from May to July 2007 on the Tibetan(or Qinghai-Tibet) Plateau,the central producing area of this precious ingredient for traditional Chinese medicine (TCM),the Xishuangbanna Tropical Botanical Garden (XTBG)under CAS conducted a further survey from May to July 2008 in the marginal habitats of this fungus.

  12. Contributions to the study of Pseudopeziza trifolii (Bernh. Fuck. fungus

    Directory of Open Access Journals (Sweden)

    Olga PALL

    1966-08-01

    Full Text Available The present paper communicates the results of the laboratory experiments concerning the behaviour of the Pseudopeziza trifolii (Bernh. Fuck. fungus that produces the clover brown leaf spot, in different culture mediums. The mycelium of the fungus develops at its best on the peptone-glucose-agar medium. The appearance of pycnides of Sporonema phacidioides Desm. type in vitro, has been reported for the fourth time in Romania especially developing on the potatoe-dextrosis-agar and plum-agar mediums.

  13. Biological control of Ascaris suum eggs by Pochonia chlamydosporia fungus.

    Science.gov (United States)

    Ferreira, Sebastião Rodrigo; de Araújo, Jackson Victor; Braga, Fábio Ribeiro; Araujo, Juliana Milani; Frassy, Luiza Neme; Ferreira, Aloízio Soares

    2011-12-01

    Ascaris suum is a gastrointestinal nematode parasite of swines. The aim of this study was to observe Pochonia chlamydosporia fungus on biological control of A. suum eggs after fungus passage through swines gastrointestinal tract. Eighteen pigs, previously dewormed, were randomly divided into three groups: group 1, treated with the fungus isolate VC4; group 2, treated with the fungus isolate VC1 and group 3 did not receive fungus (control). In the treated groups, each animal received a 9 g single dose of mycelium mass containing P. chlamydosporia (VC1 or VC4). Thereafter, animal fecal samples were collected at the following intervals: 8, 12, 24, 36, 48, 72 and 96 h after treatment beginning and these were poured in Petri dishes containing 2% water-agar culture medium. Then, 1,000 A. suum eggs were poured into each dish and kept in an incubator at 26 °C and in the dark for 30 days. After this period, approximately 100 eggs were removed from each Petri dish and morphologically analyzed under light microscopy following the ovicidal activity parameters. The higher percentage observed for isolated VC4 eggs destruction was 57.5% (36 h) after fungus administration and for isolate VC1 this percentage was 45.8% (24 h and 72 h) (p > 0.01). P. chlamydosporia remained viable after passing through the gastrointestinal tract of swines, maintaining its ability of destroying A. suum eggs.

  14. Candicidin-producing Streptomyces support leaf-cutting ants to protect their fungus garden against the pathogenic fungus Escovopsis

    OpenAIRE

    Haeder, Susanne; Wirth, Rainer; Herz, Hubert; Spiteller, Dieter

    2009-01-01

    Leaf-cutting ants such as Acromyrmex octospinosus live in obligate symbiosis with fungi of the genus Leucoagaricus, which they grow with harvested leaf material. The symbiotic fungi, in turn, serve as a major food source for the ants. This mutualistic relation is disturbed by the specialized pathogenic fungus Escovopsis sp., which can overcome Leucoagaricus sp. and thus destroy the ant colony. Microbial symbionts of leaf-cutting ants have been suggested to protect the fungus garden against Es...

  15. Molecular Characterization of a Trisegmented Mycovirus from the Plant Pathogenic Fungus Colletotrichum gloeosporioides

    Directory of Open Access Journals (Sweden)

    Jie Zhong

    2016-09-01

    Full Text Available A novel double-stranded RNA (dsRNA mycovirus, consisting of three dsRNA genome segments and possibly belonging to the family Chrysoviridae, was isolated from the filamentous phytopathogenic fungus Colletotrichum gloeosporioides and designated as Colletotrichum gloeosprioides chrysovirus 1 (CgCV1. The three dsRNAs of the CgCV1 genome with lengths of 3397, 2869, and 2630 bp (dsRNAs1–3 were found to contain a single open reading frame (ORF putatively encoding the RNA-dependent RNA polymerase (RdRp, a capsid protein, and a protease, respectively, all of which exhibited some degree of sequence similarity to the comparable putative proteins encoded by the genus Chrysovirus. The 5′- and 3′-untranslated regions in each dsRNA segment contained similar sequences that were strictly conserved at the termini. Moreover, isometric virus-like particles (VLPs with a diameter of approximately 40 nm were extracted from fungal mycelia. Phylogenetic analysis based on the conserved dsRNA1-encoded RdRp showed that CgCV1 is a new virus belonging to the Chrysoviridae family. BLAST analysis revealed the presence of CgCV1-like sequences in the chromosomes of Medicago truncatula and Solanum tuberosum. Moreover, some sequences in the transcriptome shotgun assembly (TSA library and expressed sequence tag database (ESTdb of other eudicot and monocot plants were also found to be related to CgCV1.

  16. Virulence determinants of the human pathogenic fungus Aspergillus fumigatus protect against soil amoeba predation.

    Science.gov (United States)

    Hillmann, Falk; Novohradská, Silvia; Mattern, Derek J; Forberger, Tilmann; Heinekamp, Thorsten; Westermann, Martin; Winckler, Thomas; Brakhage, Axel A

    2015-08-01

    Filamentous fungi represent classical examples for environmentally acquired human pathogens whose major virulence mechanisms are likely to have emerged long before the appearance of innate immune systems. In natural habitats, amoeba predation could impose a major selection pressure towards the acquisition of virulence attributes. To test this hypothesis, we exploited the amoeba Dictyostelium discoideum to study its interaction with Aspergillus fumigatus, two abundant soil inhabitants for which we found co-occurrence in various sites. Fungal conidia were efficiently taken up by D. discoideum, but ingestion was higher when conidia were devoid of the green fungal spore pigment dihydroxynaphtalene melanin, in line with earlier results obtained for immune cells. Conidia were able to survive phagocytic processing, and intracellular germination was initiated only after several hours of co-incubation which eventually led to a lethal disruption of the host cell. Besides phagocytic interactions, both amoeba and fungus secreted cross inhibitory factors which suppressed fungal growth or induced amoeba aggregation with subsequent cell lysis, respectively. On the fungal side, we identified gliotoxin as the major fungal factor killing Dictyostelium, supporting the idea that major virulence attributes, such as escape from phagocytosis and the secretion of mycotoxins are beneficial to escape from environmental predators.

  17. Proteomics Insights into the Biomass Hydrolysis Potentials of a Hypercellulolytic Fungus Penicillium funiculosum.

    Science.gov (United States)

    Ogunmolu, Funso Emmanuel; Kaur, Inderjeet; Gupta, Mayank; Bashir, Zeenat; Pasari, Nandita; Yazdani, Syed Shams

    2015-10-01

    The quest for cheaper and better enzymes needed for the efficient hydrolysis of lignocellulosic biomass has placed filamentous fungi in the limelight for bioprospecting research. In our search for efficient biomass degraders, we identified a strain of Penicillium funiculosum whose secretome demonstrates high saccharification capabilities. Our probe into the secretome of the fungus through qualitative and label-free quantitative mass spectrometry based proteomics studies revealed a high abundance of inducible CAZymes and several nonhydrolytic accessory proteins. The preferential association of these proteins and the attending differential biomass hydrolysis gives an insight into their interactions and clues about possible roles of novel hydrolytic and nonhydrolytic proteins in the synergistic deconstruction of lignocellulosic biomass. Our study thus provides the first comprehensive insight into the repertoire of proteins present in a high-performing secretome of a hypercellulolytic Penicillium funiculosum, their relative abundance in the secretome, and the interaction dynamics of the various protein groups in the secretome. The gleanings from the stoichiometry of these interactions hold a prospect as templates in the design of cost-effective synthetic cocktails for the optimal hydrolysis of biomass.

  18. Molecular Characterization of a Trisegmented Mycovirus from the Plant Pathogenic Fungus Colletotrichum gloeosporioides

    Science.gov (United States)

    Zhong, Jie; Pang, Xi Dan; Zhu, Hong Jian; Gao, Bi Da; Huang, Wen Kun; Zhou, Qian

    2016-01-01

    A novel double-stranded RNA (dsRNA) mycovirus, consisting of three dsRNA genome segments and possibly belonging to the family Chrysoviridae, was isolated from the filamentous phytopathogenic fungus Colletotrichum gloeosporioides and designated as Colletotrichum gloeosprioides chrysovirus 1 (CgCV1). The three dsRNAs of the CgCV1 genome with lengths of 3397, 2869, and 2630 bp (dsRNAs1–3) were found to contain a single open reading frame (ORF) putatively encoding the RNA-dependent RNA polymerase (RdRp), a capsid protein, and a protease, respectively, all of which exhibited some degree of sequence similarity to the comparable putative proteins encoded by the genus Chrysovirus. The 5′- and 3′-untranslated regions in each dsRNA segment contained similar sequences that were strictly conserved at the termini. Moreover, isometric virus-like particles (VLPs) with a diameter of approximately 40 nm were extracted from fungal mycelia. Phylogenetic analysis based on the conserved dsRNA1-encoded RdRp showed that CgCV1 is a new virus belonging to the Chrysoviridae family. BLAST analysis revealed the presence of CgCV1-like sequences in the chromosomes of Medicago truncatula and Solanum tuberosum. Moreover, some sequences in the transcriptome shotgun assembly (TSA) library and expressed sequence tag database (ESTdb) of other eudicot and monocot plants were also found to be related to CgCV1. PMID:27690081

  19. Filament Shape Versus Coronal Potential Magnetic Field Structure

    CERN Document Server

    Filippov, Boris

    2015-01-01

    Solar filament shape in projection on disc depends on the structure of the coronal magnetic field. We calculate the position of polarity inversion lines (PILs) of coronal potential magnetic field at different heights above the photosphere, which compose the magnetic neutral surface, and compare with them the distribution of the filament material in H$\\alpha$ chromospheric images. We found that the most of the filament material is enclosed between two polarity inversion lines (PILs), one at a lower height close to the chromosphere and one at a higher level, which can be considered as a height of the filament spine. Observations of the same filament on the limb by the {\\it STEREO} spacecraft confirm that the height of the spine is really very close to the value obtained from the PIL and filament border matching. Such matching can be used for filament height estimations in on-disk observations. Filament barbs are housed within protruding sections of the low-level PIL. On the base of simple model, we show that th...

  20. A Filament-Associated Halo Coronal Mass Ejection

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    There are only a few observations published so far that show the initiation of a coronal mass ejection (CME) and illustrate the magnetic changes in the surface origin of a CME. Any attempt to connect a CME with its local solar activities is meaningful. In this paper we present a clear instance of a halo CME initiation. A careful analysis of magnetograms shows that the only obvious magnetic changes in the surface region of the CME is a magnetic flux cancellation underneath a quiescent filament. The early disturbance was seen as the slow upward motion in segments of the quiescent filament. Four hours later, the filament was accelerated to about 50 km s-1 and erupted. While a small part of the material in the filament was ejected into the upper corona, most of the mass was transported to a nearby region. About forty minutes later, the transported mass was also ejected partially to the upper corona. The eruption of the filament triggered a two-ribbon flare, with post-flare loops connecting the flare ribbons. A halo CME, which is inferred to be associated with the eruptive filament, was observed from LASCO/C2 and C3. The halo CME contained two CME events, each event corresponded to a partial mass ejection of the filament. We suggest that the magnetic reconnection at the lower atmosphere is responsible for the filament eruption and the halo CME.

  1. Physical principles of filamentous protein self-assembly kinetics

    Science.gov (United States)

    Michaels, Thomas C. T.; Liu, Lucie X.; Meisl, Georg; Knowles, Tuomas P. J.

    2017-04-01

    The polymerization of proteins and peptides into filamentous supramolecular structures is an elementary form of self-organization of key importance to the functioning biological systems, as in the case of actin biofilaments that compose the cellular cytoskeleton. Aberrant filamentous protein self-assembly, however, is associated with undesired effects and severe clinical disorders, such as Alzheimer’s and Parkinson’s diseases, which, at the molecular level, are associated with the formation of certain forms of filamentous protein aggregates known as amyloids. Moreover, due to their unique physicochemical properties, protein filaments are finding extensive applications as biomaterials for nanotechnology. With all these different factors at play, the field of filamentous protein self-assembly has experienced tremendous activity in recent years. A key question in this area has been to elucidate the microscopic mechanisms through which filamentous aggregates emerge from dispersed proteins with the goal of uncovering the underlying physical principles. With the latest developments in the mathematical modeling of protein aggregation kinetics as well as the improvement of the available experimental techniques it is now possible to tackle many of these complex systems and carry out detailed analyses of the underlying microscopic steps involved in protein filament formation. In this paper, we review some classical and modern kinetic theories of protein filament formation, highlighting their use as a general strategy for quantifying the molecular-level mechanisms and transition states involved in these processes.

  2. Fossil evidence for spin alignment of SDSS galaxies in filaments

    NARCIS (Netherlands)

    Jones, Bernard J.T.; Weygaert, Rien van de; Arag´on-Calvo, Miguel A.

    2010-01-01

    We search for and find fossil evidence that the distribution of the spin axes of galaxies in cosmic web filaments relative to their host filaments are not randomly distributed. This would indicate that the action of large scale tidal torques effected the alignments of galaxies located in cosmic fila

  3. THE APPARATUS FOR ALIGNMENT OF THE PHOTOMETRIC LAMP FILAMENT

    Directory of Open Access Journals (Sweden)

    V. A. Dlugunovich

    2015-01-01

    Full Text Available During photometric measurements involving the use of photometric lamps it is necessary that the filament of lamp takes a strictly predetermined position with respect to the photodetector and the optical axis of the photometric setup. The errors in positioning of alignment filament with respect to the optical axis of the measuring system lead to increase the uncertainty of measurement of the photometric characteristics of the light sources. A typical method for alignment of filament of photometric lamps is based on the use a diopter tubes (telescopes. Using this method, the mounting of filament to the required position is carried out by successive approximations, which requires special concentration and a lot of time. The aim of this work is to develop an apparatus for alignment which allows simultaneous alignment of the filament of lamps in two mutually perpendicular planes. The method and apparatus for alignment of the photometric lamp filament during measurements of the photometric characteristics of light sources based on two digital video cameras is described in this paper. The apparatus allows to simultaneously displaying the image of lamps filament on the computer screen in two mutually perpendicular planes. The apparatus eliminates a large number of functional units requiring elementwise alignment and reduces the time required to carry out the alignment. The apparatus also provides the imaging of lamps filament with opaque coated on the bulb. The apparatus is used at the National standard of light intensity and illuminance units of the Republic of Belarus. 

  4. Calibration and Temperature Profile of a Tungsten Filament Lamp

    Science.gov (United States)

    de Izarra, Charles; Gitton, Jean-Michel

    2010-01-01

    The goal of this work proposed for undergraduate students and teachers is the calibration of a tungsten filament lamp from electric measurements that are both simple and precise, allowing to determine the temperature of tungsten filament as a function of the current intensity. This calibration procedure was first applied to a conventional filament…

  5. Intraspecific variation in aerobic and anaerobic locomotion

    DEFF Research Database (Denmark)

    Svendsen, Jon Christian; Tirsgård, Bjørn; Cordero, Gerardo A.;

    2015-01-01

    Intraspecific variation and trade-off in aerobic and anaerobic traits remain poorly understood in aquatic locomotion. Using gilthead sea bream (Sparus aurata) and Trinidadian guppy (Poecilia reticulata), both axial swimmers, this study tested four hypotheses: (1) gait transition from steady...... to unsteady (i.e., burst-assisted) swimming is associated with anaerobic metabolism evidenced as excess post exercise oxygen consumption (EPOC); (2) variation in swimming performance (critical swimming speed; U crit) correlates with metabolic scope (MS) or anaerobic capacity (i.e., maximum EPOC); (3...

  6. Energy from anaerobic methane production. [Sweden

    Energy Technology Data Exchange (ETDEWEB)

    1982-02-01

    Since 1970 Swedish researchers have been testing the ANAMET (anaerobic-aerobic-methane) process, which involves converting industrial wastewaters via an initial anaerobic microbiological step followed by an aerobic one. Recycling the biomass material in each step allows shorter hydraulic retention times without decreasing stability or solids reduction. Since the first ANAMET plants began operating at a Swedish sugar factory in 1972, 17 more plants have started up or are under construction. Moreover, the ANAMET process has engendered to offshoot BIOMET (biomass-methane) process, a thermophilic anaerobic scheme that can handle sugar-beet pulp as well as grass and other soft, fast-growing biomasses.

  7. Bending artificial muscle from nylon filaments

    Science.gov (United States)

    Mirvakili, Seyed M.; Hunter, Ian W.

    2016-04-01

    Highly oriented nylon and polyethylene fibers shrink in length and expand in diameter when heated. Using this property, in this work, for the first time we are introducing a type of bending artificial muscle from nylon filaments such as fishing line. Reversible radius of curvature of 0.23 mm-1 was achieved with maximum reversible bending amplitude of 115 mm for the nylon bending actuator. Peak force of up to 2040 mN was measured with a catch-state force of up to 40% of the active force. A 3 dB roll-off frequency of around 0.7 Hz was observed in the frequency response of the bending actuator in water.

  8. Introduction to vortex filaments in equilibrium

    CERN Document Server

    Andersen, Timothy D

    2014-01-01

    This book presents fundamental concepts and seminal results to the study of vortex filaments in equilibrium. It also presents new discoveries in quasi-2D vortex structures with applications to geophysical fluid dynamics and magnetohydrodynamics in plasmas.  It fills a gap in the vortex statistics literature by simplifying the mathematical introduction to this complex topic, covering numerical methods, and exploring a wide range of applications with numerous examples. The authors have produced an introduction that is clear and easy to read, leading the reader step-by-step into this topical area. Alongside the theoretical concepts and mathematical formulations, interesting applications are discussed. This combination makes the text useful for students and researchers in mathematics and physics.

  9. Energetic protons from a disappearing solar filament

    Energy Technology Data Exchange (ETDEWEB)

    Kahler, S.W.; Cliver, E.W.; Cane, R.E.; McGuire, H.V.; Stone, R.G.

    1985-01-01

    A solar energetic (E> 50MeV) particle (SEP) event observed at 1 AU began about 1500 UT on 1981 December 5. This event was associated with a fast coronal mass ejection observed with the Solwind coronagraph on the P78-1 satellite. No metric type II or type IV burst was observed, but a weak interplanetary type II burst was observed with the low-frequency radio experimentation ISEE-3 satellite. The mass ejection was associated with the eruption of a large solar quiescent filament that lay well away from any active regions. The eruption resulted in a H-alpha double-ribbon structure which straddled the magnetic inversion line. No impulsive phase was obvious in either the H-alpha or the microwave observations. The event indicates that neither a detectable impulsive phase nor a strong or complex magnetic field is necessary for the production of energetic ions.

  10. Validation of the filament winding process model

    Science.gov (United States)

    Calius, Emilo P.; Springer, George S.; Wilson, Brian A.; Hanson, R. Scott

    1987-01-01

    Tests were performed toward validating the WIND model developed previously for simulating the filament winding of composite cylinders. In these tests two 24 in. long, 8 in. diam and 0.285 in. thick cylinders, made of IM-6G fibers and HBRF-55 resin, were wound at + or - 45 deg angle on steel mandrels. The temperatures on the inner and outer surfaces and inside the composite cylinders were recorded during oven cure. The temperatures inside the cylinders were also calculated by the WIND model. The measured and calculated temperatures were then compared. In addition, the degree of cure and resin viscosity distributions inside the cylinders were calculated for the conditions which existed in the tests.

  11. Filament wound data base development, revision 1

    Science.gov (United States)

    Sharp, R. Scott; Braddock, William F.

    1985-01-01

    The objective was to update the present Space Shuttle Solid Rocket Booster (SRB) baseline reentry aerodynamic data base and to develop a new reentry data base for the filament wound case SRB along with individual protuberance increments. Lockheed's procedures for performing these tasks are discussed. Free fall of the SRBs after separation from the Space Shuttle Launch Vehicle is completely uncontrolled. However, the SRBs must decelerate to a velocity and attitude that is suitable for parachute deployment. To determine the SRB reentry trajectory parameters, including the rate of deceleration and attitude history during free-fall, engineers at Marshall Space Flight Center are using a six-degree-of-freedom computer program to predict dynamic behavior. Static stability aerodynamic coefficients are part of the information required for input into this computer program. Lockheed analyzed the existing reentry aerodynamic data tape (Data Tape 5) for the current steel case SRB. This analysis resulted in the development of Data Tape 7.

  12. Biophysics of filament length regulation by molecular motors

    CERN Document Server

    Kuan, Hui-Shun

    2013-01-01

    Regulating physical size is an essential problem that biological organisms must solve from the subcellular to the organismal scales, but it is not well understood what physical principles and mechanisms organisms use to sense and regulate their size. Any biophysical size-regulation scheme operates in a noisy environment and must be robust to other cellular dynamics and fluctuations. This work develops theory of filament length regulation inspired by recent experiments on kinesin-8 motor proteins, which move with directional bias on microtubule filaments and alter microtubule dynamics. Purified kinesin-8 motors can depolymerize chemically-stabilized microtubules. In the length-dependent depolymerization model, the rate of depolymerization tends to increase with filament length, because long filaments accumulate more motors at their tips and therefore shorten more quickly. When balanced with a constant filament growth rate, this mechanism can lead to a fixed polymer length. However, the mechanism by which kines...

  13. Conformations, hydrodynamic interactions, and instabilities of sedimenting semiflexible filaments

    CERN Document Server

    Saggiorato, G; Winkler, R G; Gompper, G

    2015-01-01

    The conformations and dynamics of semiflexible filaments subject to a homogeneous external (gravitational) field, e.g., in a centrifuge, are studied numerically and analytically. The competition between hydrodynamic drag and bending elasticity generates new shapes and dynamical features. We show that the shape of a semiflexible filament undergoes instabilities as the external field increases. We identify two transitions that correspond to the excitation of higher bending modes. In particular, for strong fields the filament stabilizes in a non-planar shape, resulting in a sideways drift or in helical trajectories. For two interacting filaments, we find the same transitions, with the important consequence that the new non-planar shapes have an effective hydrodynamic repulsion, in contrast to the planar shapes which attract themselves even when their osculating planes are rotated with respect to each other. For the case of planar filaments, we show analytically and numerically that the relative velocity is not n...

  14. Persistent nuclear actin filaments inhibit transcription by RNA polymerase II.

    Science.gov (United States)

    Serebryannyy, Leonid A; Parilla, Megan; Annibale, Paolo; Cruz, Christina M; Laster, Kyle; Gratton, Enrico; Kudryashov, Dmitri; Kosak, Steven T; Gottardi, Cara J; de Lanerolle, Primal

    2016-09-15

    Actin is abundant in the nucleus and it is clear that nuclear actin has important functions. However, mystery surrounds the absence of classical actin filaments in the nucleus. To address this question, we investigated how polymerizing nuclear actin into persistent nuclear actin filaments affected transcription by RNA polymerase II. Nuclear filaments impaired nuclear actin dynamics by polymerizing and sequestering nuclear actin. Polymerizing actin into stable nuclear filaments disrupted the interaction of actin with RNA polymerase II and correlated with impaired RNA polymerase II localization, dynamics, gene recruitment, and reduced global transcription and cell proliferation. Polymerizing and crosslinking nuclear actin in vitro similarly disrupted the actin-RNA-polymerase-II interaction and inhibited transcription. These data rationalize the general absence of stable actin filaments in mammalian somatic nuclei. They also suggest a dynamic pool of nuclear actin is required for the proper localization and activity of RNA polymerase II.

  15. Sedimentation of slender elastic filaments in a viscous liquid

    Science.gov (United States)

    Raspa, Veronica; Lindner, Anke; Du Roure, Olivia; Duprat, Camille

    2016-11-01

    We explore experimentally the dynamics of slender flexible filaments sedimenting in a viscous fluid at low Reynolds number. The observed deformations and dynamics result from a balance between viscous, elastic and gravitational forces on the slender body and thus are characterized by a dimensionless elasto-gravity number. We present measurements of the filaments stationary shape, velocities and trajectories for different initial conditions and filament characteristics (i.e: density, bending rigidity, size). In particular, we observe bending and reorientation of the filament, and investigate the conditions under which the filament can buckle. The introduction of elasticity broadens the spectrum of accessible sedimentation stationary states, compared to those appearing for their rigid counterparts where nor bending or buckling are allowed.

  16. Anaerobic degradation and toxicity of commercial cationic surfactants in anaerobic screening tests.

    Science.gov (United States)

    García, M T; Campos, E; Sánchez-Leal, J; Ribosa, I

    2000-09-01

    Anaerobic biodegradability and toxicity on anaerobic bacteria of di(hydrogenated tallow) dimethyl ammonium chloride (DHTDMAC) and two esterquats have been investigated. A batch test system containing municipal digester solids as a source of anaerobic bacteria, based on the method proposed by the ECETOC, has been applied. To evaluate the potential toxicity of such surfactants on anaerobic sludge, a co-substrate, an easily biodegradable compound in anaerobic conditions, has been added to the samples to test and the effects on biogas production have been determined. For the esterquats studied high biodegradation levels were obtained and no toxic effects on anaerobic bacteria were observed even at the highest concentrations tested, 100 and 200 mg C/l, respectively. On the contrary, DHTDMAC was not degradated at the same test conditions. However, no inhibitory effects on the biogas production were detected for this surfactant at concentrations <100 mg C/l.

  17. The Ecological Genomics of Fungi: Repeated Elements in Filamentous Fungi with a Focus on Wood-Decay Fungi

    Energy Technology Data Exchange (ETDEWEB)

    Murat, Claude [INRA, Nancy, France; Payen, Thibaut [INRA, Nancy, France; Petitpierre, Denis [INRA, Nancy, France; Labbe, Jessy L [ORNL

    2013-01-01

    In the last decade, the genome of several dozen filamentous fungi have been sequenced. Interestingly, vast diversity in genome size was observed (Fig. 2.1) with 14-fold differences between the 9 Mb of the human pathogenic dandruff fungus (Malassezia globosa; Xu, Saunders, et al., 2007) and the 125 Mb of the ectomycorrhizal black truffle of P rigord (Tuber melanosporum; Martin, Kohler, et al., 2010). Recently, Raffaele and Kamoun (2012) highlighted that the genomes of several lineages of filamentous plant pathogens have been shaped by repeat-driven expansion. Indeed, repeated elements are ubiquitous in all prokaryote and eukaryote genomes; however, their frequencies can vary from just a minor percentage of the genome to more that 60 percent of the genome. Repeated elements can be classified in two major types: satellites DNA and transposable elements. In this chapter, the different types of repeated elements and how these elements can impact genome and gene repertoire will be described. Also, an intriguing link between the transposable elements richness and diversity and the ecological niche will be highlighted.

  18. Antimicrobial resistance and susceptibility testing of anaerobic bacteria.

    Science.gov (United States)

    Schuetz, Audrey N

    2014-09-01

    Infections due to anaerobic bacteria can be severe and life-threatening. Susceptibility testing of anaerobes is not frequently performed in laboratories, but such testing is important to direct appropriate therapy. Anaerobic resistance is increasing globally, and resistance trends vary by geographic region. An overview of a variety of susceptibility testing methods for anaerobes is provided, and the advantages and disadvantages of each method are reviewed. Specific clinical situations warranting anaerobic susceptibility testing are discussed.

  19. Isolated Polynucleotides and Methods of Promoting a Morphology in a Fungus

    Science.gov (United States)

    Lasure, Linda L [Fall City, WA; Dai, Ziyu [Richland, WA

    2008-10-21

    The invention includes isolated polynucleotide molecules that are differentially expressed in a native fungus exhibiting a first morphology relative to the native fungus exhibiting a second morphology. The invention includes a method of enhancing a bioprocess utilizing a fungus. A transformed fungus is produced by transforming a fungus with a recombinant polynucleotide molecule. The recombinant polynucleotide molecule contains an isolated polynucleotide sequence linked operably to a promoter. The polynucleotide sequence is expressed to promote a first morphology. The first morphology of the transformed fungus enhances a bioprocess relative to the bioprocess utilizing a second morphology.

  20. Anaerobe Tolerance to Oxygen and the Potentials of Anaerobic and Aerobic Cocultures for Wastewater Treatment

    Directory of Open Access Journals (Sweden)

    M.T. Kato

    1997-12-01

    Full Text Available The anaerobic treatment processes are considered to be well-established methods for the elimination of easily biodegradable organic matter from wastewaters. Some difficulties concerning certain wastewaters are related to the possible presence of dissolved oxygen. The common belief is that anaerobes are oxygen intolerant. Therefore, the common practice is to use sequencing anaerobic and aerobic steps in separate tanks. Enhanced treatment by polishing off the residual biodegradable oxygen demand from effluents of anaerobic reactors, or the biodegradation of recalcitrant wastewater pollutants, usually requires sequenced anaerobic and aerobic bacteria activities. However, the combined activity of both bacteria can also be obtained in a single reactor. Previous experiments with either pure or mixed cultures showed that anaerobes can tolerate oxygen to a certain extent. The oxygen toxicity to methanogens in anaerobic sludges was quantified in batch experiments, as well as in anaerobic reactors. The results showed that methanogens have a high tolerance to oxygen. In practice, it was confirmed that dissolved oxygen does not constitute any detrimental effect on reactor treatment performance. This means that the coexistence of anaerobic and aerobic bacteria in one single reactor is feasible and increases the potentials of new applications in wastewater treatment

  1. Allergens of the entomopathogenic fungus Beauveria bassiana

    Directory of Open Access Journals (Sweden)

    Keyhani Nemat O

    2005-01-01

    Full Text Available Abstract Background Beauveria bassiana is an important entomopathogenic fungus currently under development as a bio-control agent for a variety of insect pests. Although reported to be non-toxic to vertebrates, the potential allergenicity of Beauveria species has not been widely studied. Methods IgE-reactivity studies were performed using sera from patients displaying mould hypersensitivity by immunoblot and immunoblot inhibition. Skin reactivity to B. bassiana extracts was measured using intradermal skin testing. Results Immunoblots of fungal extracts with pooled as well as individual sera showed a distribution of IgE reactive proteins present in B. bassiana crude extracts. Proteinase K digestion of extracts resulted in loss of IgE reactive epitopes, whereas EndoH and PNGaseF (glycosidase treatments resulted in minor changes in IgE reactive banding patterns as determined by Western blots. Immunoblot inhibitions experiments showed complete loss of IgE-binding using self protein, and partial inhibition using extracts from common allergenic fungi including; Alternaria alternata, Aspergillus fumigatus, Cladosporium herbarum, Candida albicans, Epicoccum purpurascens, and Penicillium notatum. Several proteins including a strongly reactive band with an approximate molecular mass of 35 kDa was uninhibited by any of the tested extracts, and may represent B. bassiana specific allergens. Intradermal skin testing confirmed the in vitro results, demonstrating allergenic reactions in a number of individuals, including those who have had occupational exposure to B. bassiana. Conclusions Beauveria bassiana possesses numerous IgE reactive proteins, some of which are cross-reactive among allergens from other fungi. A strongly reactive potential B. bassiana specific allergen (35 kDa was identified. Intradermal skin testing confirmed the allergenic potential of B. bassiana.

  2. Biosynthesis of active pharmaceuticals: β-lactam biosynthesis in filamentous fungi.

    Science.gov (United States)

    Van Den Berg, Marco; Gidijala, Loknath; Kiela, Jan; Bovenberg, Roel; Vander Keli, Ida

    2010-01-01

    β-lactam antibiotics (e.g. penicillins, cephalosporins) are of major clinical importance and contribute to over 40% of the total antibiotic market. These compounds are produced as secondary metabolites by certain actinomycetes and filamentous fungi (e.g. Penicillium, Aspergillus and Acremonium species). The industrial producer of penicillin is the fungus Penicillium chrysogenum. The enzymes of the penicillin biosynthetic pathway are well characterized and most of them are encoded by genes that are organized in a cluster in the genome. Remarkably, the penicillin biosynthetic pathway is compartmentalized: the initial steps of penicillin biosynthesis are catalyzed by cytosolic enzymes, whereas the two final steps involve peroxisomal enzymes. Here, we describe the biochemical properties of the enzymes of β-lactam biosynthesis in P. chrysogenum and the role of peroxisomes in this process. An overview is given on strain improvement programs via classical mutagenesis and, more recently, genetic engineering, leading to more productive strains. Also, the potential of using heterologous hosts for the development of novel ß-lactam antibiotics and non-ribosomal peptide synthetase-based peptides is discussed.

  3. Routine processing procedures for isolating filamentous fungi from respiratory sputum samples may underestimate fungal prevalence.

    Science.gov (United States)

    Pashley, Catherine H; Fairs, Abbie; Morley, Joseph P; Tailor, Shreeya; Agbetile, Joshua; Bafadhel, Mona; Brightling, Christopher E; Wardlaw, Andrew J

    2012-05-01

    Colonization of the airways by filamentous fungi can occur in asthma, chronic obstructive pulmonary disease (COPD) and cystic fibrosis. A recent study found IgE sensitization to Aspergillus fumigatus to be associated with reduced lung function. Significantly higher rates of A. fumigatus were detected in sputum from asthmatics sensitized to this fungus compared to non-sensitized asthmatics. The rate of positive cultures was far higher than equivalent historical samples analysed by the local clinical laboratory following protocols recommended by the UK Health Protection Agency (HPA). This study compares the HPA procedure with our sputum processing method, whereby sputum plugs are separated from saliva and aliquots of approximately 150 mg are inoculated directly onto potato dextrose agar. A total of 55 sputum samples from 41 patients with COPD were analyzed, comparing fungal recovery of five dilutions of sputa on two media. Isolation of A. fumigatus in culture was significantly higher using the research approach compared to the HPA standard method for mycological investigations (P < 0.001). There was also a significant difference in the recovery rate of A. fumigatus (P < 0.05) between media. This highlights the need for a standardized approach to fungal detection which is more sensitive than the method recommended by the HPA.

  4. Microbial lipid production from potato processing wastewater using oleaginous filamentous fungi Aspergillus oryzae.

    Science.gov (United States)

    Muniraj, Iniya Kumar; Xiao, Liwen; Hu, Zhenhu; Zhan, Xinmin; Shi, Jianghong

    2013-06-15

    Use of potato processing wastewater for microbial lipid production by oleaginous filamentous fungus Aspergillus oryzae was studied with the purpose of recycling potato processing wastewater for biodiesel production. The wastewater contained high concentrations of solids, starch and nutrients. Sterilization of the potato processing wastewater resulted in a thick gelatinized medium, causing the fungi to grow slow. In order to overcome this problem, the wastewater was diluted with tap water at three dilution ratios (25%, 50% and 75% before fermentation). Dilution of the wastewater not only enhanced lipid production, starch utilization and amylase secretion but also COD and nutrient removal. The dilution ratio of 25% was found to be optimum for lipid production and the maximum lipid concentration obtained was 3.5 g/L. Lipid accumulation was influenced by amylase secretion, and the amylase activity was up to 53.5 IU/mL at 25% dilution. The results show that phosphate limitation may be the mechanism to stimulate the lipid accumulation. In addition to lipid production, removals of COD, total soluble nitrogen and total soluble phosphorus up to 91%, 98% and 97% were achieved, respectively. Microbial lipids of A. oryzae contained major fatty acids such as palmitic acid (11.6%), palmitolic acid (15.6%), stearic acid (19.3%), oleic acid (30.3%), linolenic acid (5.5%) and linoleic acid (6.5%) suggesting that the lipids be suitable for second generation biodiesel production.

  5. Exocellular electron transfer in anaerobic microbial communities

    NARCIS (Netherlands)

    Stams, A.J.M.; Bok, de F.A.M.; Plugge, C.M.; Eekert, van M.H.A.; Dolfing, J.; Schraa, G.

    2006-01-01

    Exocellular electron transfer plays an important role in anaerobic microbial communities that degrade organic matter. Interspecies hydrogen transfer between microorganisms is the driving force for complete biodegradation in methanogenic environments. Many organic compounds are degraded by obligatory

  6. An anaerobic mitochondrion that produces hydrogen

    NARCIS (Netherlands)

    Boxma, Brigitte; Graaf, Rob M. de; Staay, Georg W.M. van der; Alen, Theo A. van; Ricard, Guenola; Gabaldón, Toni; Hoek, Angela H.A.M. van; Moon-van der Staay, Seung Yeo; Koopman, Werner J.H.; Hellemond, Jaap J. van; Tielens, Aloysius G.M.; Friedrich, Thorsten; Veenhuis, Marten; Huynen, Martijn A.; Hackstein, Johannes H.P.

    2005-01-01

    Hydrogenosomes are organelles that produce ATP and hydrogen, and are found in various unrelated eukaryotes, such as anaerobic flagellates, chytridiomycete fungi and ciliates. Although all of these organelles generate hydrogen, the hydrogenosomes from these organisms are structurally and metabolicall

  7. Anaerobic Toxicity of Cationic Silver Nanoparticles

    Data.gov (United States)

    U.S. Environmental Protection Agency — Toxicity data for the impact of nano-silver on anaerobic degradation. This dataset is associated with the following publication: Gitipour, A., S. Thiel, K. Scheckel,...

  8. Anaerobic membrane bioreactor under extreme conditions (poster)

    NARCIS (Netherlands)

    Munoz Sierra, J.D.; De Kreuk, M.K.; Spanjers, H.; Van Lier, J.B.

    2013-01-01

    Membrane bioreactors ensure biomass retention by the application of micro or ultrafiltration processes. This allows operation at high sludge concentrations. Previous studies have shown that anaerobic membrane bioreactors is an efficient way to retain specialist microorganisms for treating wastewater

  9. EFFECT OF MUSIC ON ANAEROBIC EXERCISE PERFORMANCE

    OpenAIRE

    Atan, T.

    2013-01-01

    For years, mostly the effects of music on cardiorespiratory exercise performance have been studied, but a few studies have examined the effect of music on anaerobic exercise. The purpose of this study was to assess the effect of listening to music and its rhythm on anaerobic exercise: on power output, heart rate and the concentration of blood lactate. 28 male subjects were required to visit the laboratory on 6 occasions, each separated by 48 hours. Firstly, each subject performed the Running-...

  10. Anaerobic digester for treatment of organic waste

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, V. K. [Indian Insitute of Technology, Delhi (India)]|[ENEA, Centro Ricerche Trisaia, Matera (Italy); Fortuna, F.; Canditelli, M.; Cornacchia, G. [ENEA, Centro Ricerche Trisaia, Matera (Italy). Dipt. Ambiente; Farina, R. [ENEA, centro Ricerche ``Ezio Clementel``, Bologna (Italy). Dipt. Ambiente

    1997-09-01

    The essential features of both new and more efficient reactor systems and their appropriate applications for various organic waste management situations, description of several working plants are discussed in the present communication. It is hoped that significant development reported here would be useful in opening a new vista to the application of anaerobic biotechnology for the waste treatment of both low/high organic strength and specialized treatment for toxic substances, using appropriate anaerobic methods.

  11. Anaerobic digestion foaming causes – A review

    OpenAIRE

    Ganidi, Nafsika; Tyrrel, Sean F.; Cartmell, Elise

    2009-01-01

    Anaerobic digestion foaming has been encountered in several sewage treatment plants in the UK. Foaming has raised major concerns for the water companies due to significant impacts on process efficiency and operational costs. Several foaming causes have been identified over the past few years by researchers. However, the supporting experimental information is limited and in some cases absent. The present report aims to provide a detailed review of the current anaerobic digestion foaming proble...

  12. Adherence to abiotic surface induces SOS response in Escherichia coli K-12 strains under aerobic and anaerobic conditions.

    Science.gov (United States)

    Costa, Suelen B; Campos, Ana Carolina C; Pereira, Ana Claudia M; de Mattos-Guaraldi, Ana Luiza; Júnior, Raphael Hirata; Rosa, Ana Cláudia P; Asad, Lídia M B O

    2014-09-01

    During the colonization of surfaces, Escherichia coli bacteria often encounter DNA-damaging agents and these agents can induce several defence mechanisms. Base excision repair (BER) is dedicated to the repair of oxidative DNA damage caused by reactive oxygen species (ROS) generated by chemical and physical agents or by metabolism. In this work, we have evaluated whether the interaction with an abiotic surface by mutants derived from E. coli K-12 deficient in some enzymes that are part of BER causes DNA damage and associated filamentation. Moreover, we studied the role of endonuclease V (nfi gene; 1506 mutant strain) in biofilm formation. Endonuclease V is an enzyme that is involved in DNA repair of nitrosative lesions. We verified that endonuclease V is involved in biofilm formation. Our results showed more filamentation in the xthA mutant (BW9091) and triple xthA nfo nth mutant (BW535) than in the wild-type strain (AB1157). By contrast, the mutant nfi did not present filamentation in biofilm, although its wild-type strain (1466) showed rare filaments in biofilm. The filamentation of bacterial cells attaching to a surface was a consequence of SOS induction measured by the SOS chromotest. However, biofilm formation depended on the ability of the bacteria to induce the SOS response since the mutant lexA Ind(-) did not induce the SOS response and did not form any biofilm. Oxygen tension was an important factor for the interaction of the BER mutants, since these mutants exhibited decreased quantitative adherence under anaerobic conditions. However, our results showed that the presence or absence of oxygen did not affect the viability of BW9091 and BW535 strains. The nfi mutant and its wild-type did not exhibit decreased biofilm formation under anaerobic conditions. Scanning electron microscopy was also performed on the E. coli K-12 strains that had adhered to the glass, and we observed the presence of a structure similar to an extracellular matrix that depended on the

  13. SLEEP DEPRIVATION INDUCED ANXIETY AND ANAEROBIC PERFORMANCE

    Directory of Open Access Journals (Sweden)

    Selma Arzu Vardar

    2007-12-01

    Full Text Available The aim of this study was to investigate the effects of sleep deprivation induced anxiety on anaerobic performance. Thirteen volunteer male physical education students completed the Turkish version of State Anxiety Inventory and performed Wingate anaerobic test for three times: (1 following a full-night of habitual sleep (baseline measurements, (2 following 30 hours of sleep deprivation, and (3 following partial-night sleep deprivation. Baseline measurements were performed the day before total sleep deprivation. Measurements following partial sleep deprivation were made 2 weeks later than total sleep deprivation measurements. State anxiety was measured prior to each Wingate test. The mean state anxiety following total sleep deprivation was higher than the baseline measurement (44.9 ± 12.9 vs. 27.6 ± 4.2, respectively, p = 0.02 whereas anaerobic performance parameters remained unchanged. Neither anaerobic parameters nor state anxiety levels were affected by one night partial sleep deprivation. Our results suggest that 30 hours continuous wakefulness may increase anxiety level without impairing anaerobic performance, whereas one night of partial sleep deprivation was ineffective on both state anxiety and anaerobic performance

  14. An observational detection of the bridge effect of void filaments

    CERN Document Server

    Shim, Junsup; Hoyle, Fiona

    2015-01-01

    The bridge effect of void filaments is a phrase coined by Park & Lee (2009b) to explain the correlations found in a numerical experiment between the luminosity of the void galaxies and the degree of the straightness of their host filaments. Their numerical finding implies that a straight void filament provides a narrow channel for the efficient transportation of gas and matter particles from the surroundings into the void galaxies. To observationally confirm the presence of the bridge effect of void filaments, we identify the filamentary structures from the Sloan void catalog and determine the specific size of each void filament as a measure of its straightness. Using both classical and Bayesian statistics, we indeed detect a strong tendency that the void galaxies located in the more straight filaments are on average more luminous, which is in agreement with the numerical prediction. It is also shown that the strength of correlation increases with the spatial extent of the void filaments, which can be phy...

  15. Is Gravitational Lensing by Intercluster Filaments Always Negligible?

    CERN Document Server

    Xu, Dong; Shan, HuanYuan; Famaey, Benoit; Limousin, Marceau; Zhao, HongSheng

    2007-01-01

    Intercluster filaments negligibly contribute to the weak lensing signal in General Relativity (GR), $\\gamma_{N}\\sim 10^{-4}-10^{-3}$. In the context of relativistic Modified Newtonian Dynamics (MOND) (Bekenstein 2004), however, a single filament inclined by $\\approx 45^\\circ$ from the line of sight can cause substantial distortion of background sources pointing towards the filament's axis ($\\kappa=\\gamma=(1-A^{-1})/2\\sim 0.01$); this is rigourous for infinitely long uniform filaments, but also qualitatively true for short filaments ($\\sim 30$Mpc), and even in regions where the projected matter density of the filament equals to zero. Since galaxies and galaxy clusters are generally embedded in filaments or are projected on such structures, this contribution complicates the interpretation of the weak lensing shear map in the context of MOND. While our analysis is of mainly theoretical interest providing order-of-magnitude estimates only, it seems safe to conclude that when modeling systems with anomalous weak l...

  16. Origin of the dense core mass function in contracting filaments

    CERN Document Server

    Myers, Philip C

    2013-01-01

    Mass functions of starless dense cores (CMFs) may arise from contraction and dispersal of core-forming filaments. In an illustrative model, a filament contracts radially by self-gravity, increasing the mass of its cores. During this contraction, FUV photoevaporation and ablation by shocks and winds disperse filament gas and limit core growth. The stopping times of core growth are described by a waiting-time distribution. The initial filament column density profile and the resulting CMF each match recent Herschel observations in detail. Then low-mass cores have short growth ages and arise from the innermost filament gas, while massive cores have long growth ages and draw from more extended filament gas. The model fits the initial density profile and CMF best for mean core density 2 10^4 cm^-3 and filament dispersal time scale 0.5 Myr. Then the typical core mass, radius, mean column density, and contraction speed are respectively 0.8 solar masses, 0.06 pc, 6 10^21 cm^-2, and 0.07 km s^-1, also in accord with ob...

  17. The supramolecular organization of the C. elegans nuclear lamin filament.

    Science.gov (United States)

    Ben-Harush, Kfir; Wiesel, Naama; Frenkiel-Krispin, Daphna; Moeller, Dorothee; Soreq, Eyal; Aebi, Ueli; Herrmann, Harald; Gruenbaum, Yosef; Medalia, Ohad

    2009-03-13

    Nuclear lamins are involved in most nuclear activities and are essential for retaining the mechano-elastic properties of the nucleus. They are nuclear intermediate filament (IF) proteins forming a distinct meshwork-like layer adhering to the inner nuclear membrane, called the nuclear lamina. Here, we present for the first time, the three-dimensional supramolecular organization of lamin 10 nm filaments and paracrystalline fibres. We show that Caenorhabditis elegans nuclear lamin forms 10 nm IF-like filaments, which are distinct from their cytoplasmic counterparts. The IF-like lamin filaments are composed of three and four tetrameric protofilaments, each of which contains two partially staggered anti-parallel head-to-tail polymers. The beaded appearance of the lamin filaments stems from paired globular tail domains, which are spaced regularly, alternating between 21 nm and 27 nm. A mutation in an evolutionarily conserved residue that causes Hutchison-Gilford progeria syndrome in humans alters the supramolecular structure of the lamin filaments. On the basis of our structural analysis, we propose an assembly pathway that yields the observed 10 nm IF-like lamin filaments and paracrystalline fibres. These results serve also as a platform for understanding the effect of laminopathic mutations on lamin supramolecular organization.

  18. Investigating the Global Collapse of Filaments Using Smoothed Particle Hydrodynamics

    CERN Document Server

    Clarke, Seamus D

    2015-01-01

    We use Smoothed Particle Hydrodynamic simulations of cold, uniform density, self-gravitating filaments, to investigate their longitudinal collapse timescales; these timescales are important because they determine the time available for a filament to fragment into cores. A filament is initially characterised by its line-mass, $\\mu$, its radius, $R$ (or equivalently its density $\\rho\\!=\\!\\mu/\\pi R^2$), and its aspect ratio, $A\\;\\,(\\equiv Z/R$, where $Z$ is its half-length). The gas is only allowed to contract longitudinally, i.e. parallel to the symmetry axis of the filament (the $z$-axis). Pon et al. (2012) have considered the global dynamics of such filaments analytically. They conclude that short filaments ($A\\! \\!5$) undergo end-dominated collapse, i.e. two dense clumps form at the ends of the filament and converge on the centre sweeping up mass as they go, on a time-scale $t_{_{\\rm END}} \\sim 0.98\\,A^{1/2}\\,(G\\rho)^{-1/2}$. Our simulations do not corroborate these predictions. First, for all $A\\! > \\!2$, ...

  19. MUSE discovers perpendicular arcs in Cen A inner filament

    CERN Document Server

    Hamer, Stephen; Combes, Francoise; Salomé, Quentin

    2014-01-01

    Evidence of AGN interaction with the intergalactic medium is observed in some galaxies and many cool core clusters. Radio-jets are suspected to dig large cavities into the surrounding gas. In most cases, very large optical filaments (several kpc) are also seen all around the central galaxy. The origin of these filaments is still not understood. Star forming regions are sometimes observed inside the filaments and are interpreted as evidence of positive feedback (AGN-triggered star formation). Cen A is a very nearby galaxy with huge optical filaments aligned with AGN radio-jet direction. Here, we search for line ratio variations along the filaments, kinematic evidence of shock-broadend line widths and large scale dynamical structures. We observe a 1'x1' region around the inner filament of Cen A with MUSE on the VLT during the Science Verification period. The brightest lines are the Halpha, [NII], [OIII] and [SII]. MUSE shows that the filaments are made of clumpy structures inside a more diffuse medium aligned w...

  20. Fossil evidence for spin alignment of SDSS galaxies in filaments

    CERN Document Server

    Jones, Bernard J T; Aragon-Calvo, Miguel A

    2010-01-01

    We search for and find fossil evidence that the distribution of the spin axes of galaxies in cosmic web filaments relative to their host filaments are not randomly distributed. This would indicate that the action of large scale tidal torques effected the alignments of galaxies located in cosmic filaments. To this end, we constructed a catalogue of clean filaments containing edge-on galaxies. We started by applying the Multiscale Morphology Filter (MMF) technique to the galaxies in a redshift-distortion corrected version of the Sloan Digital Sky Survey DR5. From that sample we extracted those 426 filaments that contained edge-on galaxies (b/a < 0.2). These filaments were then visually classified relative to a variety of quality criteria. Statistical analysis using "feature measures" indicates that the distribution of orientations of these edge-on galaxies relative to their parent filament deviate significantly from what would be expected on the basis of a random distribution of orientations. The interpretat...

  1. Formation of interstellar filaments: the role of magnetic fields

    Science.gov (United States)

    Ntormousi, Evangelia; Hennebelle, Patrick

    2014-07-01

    The filamentary structure of interstellar matter and its potential link to star formation has been brought back into focus recently by high resolution observational surveys. The densest of these filaments host pre-stellar and star forming cores, so explaining their properties is tightly correlated to revealing the initial conditions for star formation. To that end, in this work we employ high-resolution, 3D MHD simulations performed with the AMR code RAMSES to investigate two filament formation mechanisms: turbulence and sheet fragmentation. The first series of simulations has as a particular aim to address the origin of the characteristic filament thickness found in observations. Starting from the hypothesis that diffusive processes are responsible, our numerical experiments consist of (driven or decaying) ideal and non-ideal MHD turbulence, at a resolution that greatly exceeds the reported 0.1pc thickness. The comparison points to ion-neutral friction as an excellent candidate for setting a characteristic scale. In this picture dense filaments are the diffusive end of the turbulent cascade, an interpretation with important implications for our understanding of the dynamical behavior of the ISM. A second series of simulations investigates filament formation by the fragmentation of supershells, a scenario inspired by the analytical work of Nagai (1998). We find a striking difference between hydrodynamical and MHD runs as in the first case the sheets fragment into small cores, while in the latter they produce large filaments. In addition though, we see that low-density filaments preferentially form along the dominant component of the magnetic field. In this scenario filaments are prominent features in the ISM, but their fate is still determined by the local magnetic field. A detailed comparison of the filament properties between the two runs is work in progress and will reveal the physical mechanisms responsible for shaping the ISM and setting the initial conditions

  2. Organic Acid Production by Filamentous Fungi

    Energy Technology Data Exchange (ETDEWEB)

    Magnuson, Jon K.; Lasure, Linda L.

    2004-05-03

    Many of the commercial production processes for organic acids are excellent examples of fungal biotechnology. However, unlike penicillin, the organic acids have had a less visible impact on human well-being. Indeed, organic acid fermentations are often not even identified as fungal bioprocesses, having been overshadowed by the successful deployment of the β-lactam processes. Yet, in terms of productivity, fungal organic acid processes may be the best examples of all. For example, commercial processes using Aspergillus niger in aerated stirred-tank-reactors can convert glucose to citric acid with greater than 80% efficiency and at final concentrations in hundreds of grams per liter. Surprisingly, this phenomenal productivity has been the object of relatively few research programs. Perhaps a greater understanding of this extraordinary capacity of filamentous fungi to produce organic acids in high concentrations will allow greater exploitation of these organisms via application of new knowledge in this era of genomics-based biotechnology. In this chapter, we will explore the biochemistry and modern genetic aspects of the current and potential commercial processes for making organic acids. The organisms involved, with a few exceptions, are filamentous fungi, and this review is limited to that group. Although yeasts including Saccharomyces cerevisiae, species of Rhodotorula, Pichia, and Hansenula are important organisms in fungal biotechnology, they have not been significant for commercial organic acid production, with one exception. The yeast, Yarrowia lipolytica, and related yeast species, may be in use commercially to produce citric acid (Lopez-Garcia, 2002). Furthermore, in the near future engineered yeasts may provide new commercial processes to make lactic acid (Porro, Bianchi, Ranzi, Frontali, Vai, Winkler, & Alberghina, 2002). This chapter is divided into two parts. The first contains a review of the commercial aspects of current and potential large

  3. HIERARCHICAL FRAGMENTATION OF THE ORION MOLECULAR FILAMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Takahashi, Satoko; Ho, Paul T. P.; Su, Yu-Nung [Academia Sinica Institute of Astronomy and Astrophysics, P.O. Box 23-141, Taipei 10617, Taiwan (China); Teixeira, Paula S. [Institut fuer Astrophysik, Universitaet Wien, Tuerkenschanzstrasse 17, A-1180, Wien (Austria); Zapata, Luis A., E-mail: satoko_t@asiaa.sinica.edu.tw [Centro de Radioastronomia y Astrofisica, Universidad Nacional Autonoma de Mexico, Morelia, Michoacan 58090 (Mexico)

    2013-01-20

    We present a high angular resolution map of the 850 {mu}m continuum emission of the Orion Molecular Cloud-3 (OMC 3) obtained with the Submillimeter Array (SMA); the map is a mosaic of 85 pointings covering an approximate area of 6.'5 Multiplication-Sign 2.'0 (0.88 Multiplication-Sign 0.27 pc). We detect 12 spatially resolved continuum sources, each with an H{sub 2} mass between 0.3-5.7 M {sub Sun} and a projected source size between 1400-8200 AU. All the detected sources are on the filamentary main ridge (n{sub H{sub 2}}{>=}10{sup 6} cm{sup -3}), and analysis based on the Jeans theorem suggests that they are most likely gravitationally unstable. Comparison of multi-wavelength data sets indicates that of the continuum sources, 6/12 (50%) are associated with molecular outflows, 8/12 (67%) are associated with infrared sources, and 3/12 (25%) are associated with ionized jets. The evolutionary status of these sources ranges from prestellar cores to protostar phase, confirming that OMC-3 is an active region with ongoing embedded star formation. We detect quasi-periodical separations between the OMC-3 sources of Almost-Equal-To 17''/0.035 pc. This spatial distribution is part of a large hierarchical structure that also includes fragmentation scales of giant molecular cloud ( Almost-Equal-To 35 pc), large-scale clumps ( Almost-Equal-To 1.3 pc), and small-scale clumps ( Almost-Equal-To 0.3 pc), suggesting that hierarchical fragmentation operates within the Orion A molecular cloud. The fragmentation spacings are roughly consistent with the thermal fragmentation length in large-scale clumps, while for small-scale cores it is smaller than the local fragmentation length. These smaller spacings observed with the SMA can be explained by either a helical magnetic field, cloud rotation, or/and global filament collapse. Finally, possible evidence for sequential fragmentation is suggested in the northern part of the OMC-3 filament.

  4. Potential for nitrogen fixation in fungus-growing termite symbioses

    Directory of Open Access Journals (Sweden)

    Panagiotis Sapountzis

    2016-12-01

    Full Text Available Termites host a gut microbiota of diverse and essential symbionts that enable specialization on dead plant material; an abundant, but nutritionally imbalanced food source. To supplement the severe shortage of dietary nitrogen (N, some termite species make use of diazotrophic bacteria to fix atmospheric nitrogen (N2. Fungus-growing termites (subfamily Macrotermitinae host a fungal exosymbiont (genus Termitomyces that provides digestive services and the main food source for the termites. This has been thought to obviate the need for N2-fixation by bacterial symbionts. Here we challenge this notion by performing acetylene reduction assays of live colony material to show that N2 fixation is present in two major genera (Macrotermes and Odontotermes of fungus-growing termites. We compare and discuss fixation rates in relation to those obtained from other termites, and suggest avenues of research that may lead to a better understanding of N2 fixation in fungus-growing and other termites.

  5. Evolutionary patterns of proteinase activity in attine ant fungus gardens

    DEFF Research Database (Denmark)

    Semenova, Tatyana; Hughes, David Peter; Boomsma, Jacobus Jan;

    2011-01-01

    hypothesized that fungal proteinase activity may have been under selection for efficiency and that different classes of proteinases might be involved. Results: We determined proteinase activity profiles across a wide pH range for fungus gardens of 14 Panamanian species of fungus-growing ants, representing...... eight genera. We mapped these activity profiles on an independently obtained molecular phylogeny of the symbionts and show that total proteinase activity in lower attine symbionts peaks at ca. pH 6. The higher attine symbionts that have no known free-living relatives had much higher proteinase...... activities than the lower attine symbionts. Their total in vitro proteinase activity peaked at pH values around 5, which is close to the pH that the ants maintain in their fungus gardens, suggesting that the pH optimum of fungal proteinases may have changed after the irreversible domestication...

  6. Rock Phosphate Solubilization Mechanisms of One Fungus and One Bacterium

    Institute of Scientific and Technical Information of China (English)

    LIN Qi-mei; ZHAO Xiao-rong; ZHAO Zi-juan; LI Bao-guo

    2002-01-01

    Many microorganisms can dissolve the insoluble phosphates like apatite. However, the mechanisms are still not clear. This study was an attempt to investigate the mechanisms of rock phosphate solubilization by an Aspergillus 2TCiF2 and an Arthrobacter1TCRi7. The results indicated that the fungus produced a large amount of organic acids, mainly oxalic acid. The total quantity of the organic acids produced by the fungus was 550 times higher than that by the bacterium. Different organic acids had completely different capacities to solubilize the rock. Oxalic acid and citric acid had stronger capacity to dissolve the rock than malic acid, tartaric acid, lactic acid, acetic acid, malonic acid and succinic acid. The fungus solubilized the rock through excreting both proton and organic acids. The rock solubilization of the bacterium depended on only proton.

  7. Is the periplasm continuous in filamentous multicellular cyanobacteria?

    Science.gov (United States)

    Flores, Enrique; Herrero, Antonia; Wolk, C Peter; Maldener, Iris

    2006-10-01

    Filamentous, heterocyst-forming cyanobacteria are multicellular organisms in which individual cells exchange nutrients and, presumably, regulatory molecules. Unknown mechanisms underlie this exchange. Classical electron microscopy shows that filamentous cyanobacteria bear a Gram-negative cell wall comprising a peptidoglycan layer and an outer membrane that are external to the cytoplasmic membrane, and that the outer membrane appears to be continuous along the filament of cells. This implies that the periplasmic space between the cytoplasmic and outer membranes might also be continuous. We propose that a continuous periplasm could constitute a communication conduit for the transfer of compounds, which is essential for the performance of these bacteria as multicellular organisms.

  8. Failure and nonfailure of fluid filaments in extension

    DEFF Research Database (Denmark)

    Hassager, Ole; Kolte, Mette Irene; Renardy, Michael

    1998-01-01

    fluid filaments do not exhibit ductile failure without surface tension; (2) some viscoelastic fluids form stable filaments while other fluids exhibit ductile failure as a result of an elastic instability; (3) for large Deborah numbers, the Considere condition may be used to predict the Hencky strain......The phenomenon of ductile failure of Newtonian and viscoelastic fluid filaments without surface tension is studied by a 2D finite element method and by ID non-linear analysis. The viscoelastic fluids are described by single integral constitutive equations. The main conclusions are: (1) Newtonian...

  9. Anaerobic Nitrogen Fixers on Mars

    Science.gov (United States)

    Lewis, B. G.

    2000-07-01

    The conversion of atmospheric nitrogen gas to the protein of living systems is an amazing process of nature. The first step in the process is biological nitrogen fixation, the transformation of N2 to NH3. The phenomenon is crucial for feeding the billions of our species on Earth. On Mars, the same process may allow us to discover how life can adapt to a hostile environment, and render it habitable. Hostile environments also exist on Earth. For example, nothing grows in coal refuse piles due to the oxidation of pyrite and marcasite to sulfuric acid. Yet, when the acidity is neutralized, alfalfa and soybean plants develop root nodules typical of symbiotic nitrogen fixation with Rhizobium species possibly living in the pyritic material. When split open, these nodules exhibited the pinkish color of leghemoglobin, a protein in the nodule protecting the active nitrogen-fixing enzyme nitrogenase against the toxic effects of oxygen. Although we have not yet obtained direct evidence of nitrogenase activity in these nodules (reduction of acetylene to ethylene, for example), these findings suggested the possibility that nitrogen fixation was taking place in this hostile, non-soil material. This immediately raises the possibility that freeliving anaerobic bacteria which fix atmospheric nitrogen on Earth, could do the same on Mars.

  10. Isolation and identification of iron ore-solubilising fungus

    Directory of Open Access Journals (Sweden)

    Damase Khasa

    2010-09-01

    Full Text Available Potential mineral-solubilising fungi were successfully isolated from the surfaces of iron ore minerals. Four isolates were obtained and identified by molecular and phylogenetic methods as close relatives of three different genera, namely Penicillium (for isolate FO, Alternaria (for isolates SFC2 and KFC1 and Epicoccum (for isolate SFC2B. The use of tricalcium phosphate (Ca3(PO42in phosphate-solubilising experiments confirmed isolate FO as the only phosphate solubiliser among the isolated fungi. The bioleaching capabilities of both the fungus and its spent liquid medium were tested and compared using two types of iron ore materials, conglomerate and shale, from the Sishen Iron Ore Mine as sources of potassium (K and phosphorus (P. The spent liquid medium removed more K (a maximum of 32.94% removal, from conglomerate, than the fungus (a maximum of 21.36% removal, from shale. However, the fungus removed more P (a maximum of 58.33% removal, from conglomerate than the spent liquid medium (a maximum of 29.25% removal, from conglomerate. The results also indicated a potential relationship between the removal of K or P and the production of organic acids by the fungus. A high production of gluconic acid could be related to the ability of the fungus to reduce K and P. Acetic, citric and maleic acids were also produced by the fungus, but in lower quantities. In addition, particle size and iron ore type were also shown to have significant effects on the removal of potassium and phosphorus from the iron ore minerals. We therefore conclude that the spent liquid medium from the fungal isolate FO can potentially be used for biobeneficiation of iron ore minerals.

  11. Exploring the Potential for Actinobacteria as Defensive Symbionts in Fungus-Growing Termites

    NARCIS (Netherlands)

    Visser, A.A.; Mesquita Nobre, T.; Currie, C.R.; Aanen, D.K.; Poulsen, M.

    2012-01-01

    In fungus-growing termites, fungi of the subgenus Pseudoxylaria threaten colony health through substrate competition with the termite fungus (Termitomyces). The potential mechanisms with which termites suppress Pseudoxylaria have remained unknown. Here we explore if Actinobacteria potentially play a

  12. A Comparison Study of a Solar Active-Region Eruptive Filament and a Neighboring Non-Eruptive Filament

    CERN Document Server

    Jiang, Chaowei; Feng, Xueshang; Hu, Qiang

    2015-01-01

    Solar active region (AR) 11283 is a very magnetically complex region and it has produced many eruptions. However, there exists a non-eruptive filament in the plage region just next to an eruptive one in the AR, which gives us an opportunity to perform a comparison analysis of these two filaments. The coronal magnetic field extrapolated using a CESE-MHD-NLFFF code (Jiang & Feng 2013) reveals that two magnetic flux ropes (MFRs) exist in the same extrapolation box supporting these two filaments, respectively. Analysis of the magnetic field shows that the eruptive MFR contains a bald-patch separatrix surface (BPSS) co-spatial very well with a pre-eruptive EUV sigmoid, which is consistent with the BPSS model for coronal sigmoids. The magnetic dips of the non-eruptive MFRs match H{\\alpha} observation of the non-eruptive filament strikingly well, which strongly supports the MFR-dip model for filaments. Compared with the non-eruptive MFR/filament (with a length of about 200 Mm), the eruptive MFR/filament is much ...

  13. Application of dynamic membranes in anaerobic membranes in anaerobic membrane bioreactor systems

    NARCIS (Netherlands)

    Erşahin, M.E.

    2015-01-01

    Anaerobic membrane bioreactors (AnMBRs) physically ensure biomass retention by the application of a membrane filtration process. With growing application experiences from aerobic membrane bioreactors (MBRs), the combination of membrane and anaerobic processes has received much attention and become m

  14. Pseudoxylaria as stowaway of the fungus-growing termite nest:

    DEFF Research Database (Denmark)

    Visser, Anna A.; Kooij, Pepijn Wilhelmus; Debets, Alfons J. M.

    2011-01-01

    Though inconspicuous in healthy nests, Pseudoxylaria species are almost always present and overgrow deteriorating fungus-growing termite gardens. Whether these fungi are detrimental to the fungus-garden, benign, or even beneficial is unclear. We hypothesize that Pseudoxylaria is a stowaway...... that practices a sit-and-wait strategy to survive in the termite nest. Using isolates from three different termite genera to test our hypothesis, we compared Pseudoxylaria’s growth on 40 carbon sources with that of Termitomyces and tested its interaction with Termitomyces. The C-source use of both fungi largely...

  15. Enhancing Nonribosomal Peptide Biosynthesis in Filamentous Fungi

    Science.gov (United States)

    Soukup, Alexandra A.; Keller, Nancy P.; Wiemann, Philipp

    2016-01-01

    Filamentous fungi are historically known as rich sources for production of biologically active natural products, so-called secondary metabolites. One particularly pharmaceutically relevant chemical group of secondary metabolites is the nonribosomal peptides synthesized by nonribosomal peptide synthetases (NRPSs). As most of the fungal NRPS gene clusters leading to production of the desired molecules are not expressed under laboratory conditions, efforts to overcome this impediment are crucial to unlock the full chemical potential of each fungal species. One way to activate these silent clusters is by overexpressing and deleting global regulators of secondary metabolism. The conserved fungal-specific regulator of secondary metabolism, LaeA, was shown to be a valuable target for sleuthing of novel gene clusters and metabolites. Additionally, modulation of chromatin structures by either chemical or genetic manipulation has been shown to activate cryptic metabolites. Furthermore, NRPS-derived molecules seem to be affected by cross talk between the specific gene clusters and some of these metabolites have a tissue- or developmental-specific regulation. This chapter summarizes how this knowledge of different tiers of regulation can be combined to increase production of NRPS-derived metabolites in fungal species. PMID:26831707

  16. Cold Milky Way Hi gas in filaments

    CERN Document Server

    Kalberla, P M W; Haud, U; Winkel, B; Bekhti, N Ben; Floeer, L; Lenz, D

    2016-01-01

    We investigate data from the Galactic Effelsberg--Bonn HI Survey (EBHIS), supplemented with data from the third release of the Galactic All Sky Survey (GASS III) observed at Parkes. We explore the all sky distribution of the local Galactic HI gas with $|v_{\\rm LSR}| 20^\\circ$ is described by a log-normal distribution, with a median Doppler temperature $T_{\\rm D} = 223$ K, derived from observed line widths that include turbulent contributions. The median neutral hydrogen (HI) column density is $N_{\\rm HI} \\simeq 10^{19.1}\\,{\\rm cm^{-2}}$. These CNM structures are embedded within a warm neutral medium (WNM) with $N_{\\rm HI} \\simeq 10^{20} {\\rm cm^{-2}}$. Assuming an average distance of 100 pc, we derive for the CNM sheets a thickness of $< 0.3$ pc. Adopting a magnetic field strength of $B_{\\rm tot} = (6.0 \\pm 1.8)\\mu$G, proposed by Heiles & Troland 2005, and assuming that the CNM filaments are confined by magnetic pressure, we estimate a thickness of 0.09 pc. Correspondingly the median volume density is ...

  17. The Apis mellifera Filamentous Virus Genome

    Directory of Open Access Journals (Sweden)

    Laurent Gauthier

    2015-07-01

    Full Text Available A complete reference genome of the Apis mellifera Filamentous virus (AmFV was determined using Illumina Hiseq sequencing. The AmFV genome is a double stranded DNA molecule of approximately 498,500 nucleotides with a GC content of 50.8%. It encompasses 247 non-overlapping open reading frames (ORFs, equally distributed on both strands, which cover 65% of the genome. While most of the ORFs lacked threshold sequence alignments to reference protein databases, twenty-eight were found to display significant homologies with proteins present in other large double stranded DNA viruses. Remarkably, 13 ORFs had strong similarity with typical baculovirus domains such as PIFs (per os infectivity factor genes: pif-1, pif-2, pif-3 and p74 and BRO (Baculovirus Repeated Open Reading Frame. The putative AmFV DNA polymerase is of type B, but is only distantly related to those of the baculoviruses. The ORFs encoding proteins involved in nucleotide metabolism had the highest percent identity to viral proteins in GenBank. Other notable features include the presence of several collagen-like, chitin-binding, kinesin and pacifastin domains. Due to the large size of the AmFV genome and the inconsistent affiliation with other large double stranded DNA virus families infecting invertebrates, AmFV may belong to a new virus family.

  18. Equilibrium theory for braided elastic filaments

    Science.gov (United States)

    van der Heijden, Gert

    Motivated by supercoiling of DNA and other filamentous structures, we formulate a theory for equilibria of 2-braids, i.e., structures formed by two elastic rods winding around each other in continuous contact and subject to a local interstrand interaction. Unlike in previous work no assumption is made on the shape of the contact curve. Rather, this shape is found as part of the solution. The theory is developed in terms of a moving frame of directors attached to one of the strands with one of the directors pointing to the position of the other strand. The constant-distance constraint is automatically satisfied by the introduction of what we call braid strains. The price we pay is that the potential energy involves arclength derivatives of these strains, thus giving rise to a second-order variational problem. The Euler-Lagrange equations for this problem give balance equations for the overall braid force and moment referred to the moving frame as well as differential equations that can be interpreted as effective constitutive relations encoding the effect that the second strand has on the first as the braid deforms under the action of end loads. Simple analytical cases are discussed first and used as starting solutions in parameter continuation studies to compute classes of both open and closed (linked or knotted) braid solutions.

  19. The Apis mellifera Filamentous Virus Genome.

    Science.gov (United States)

    Gauthier, Laurent; Cornman, Scott; Hartmann, Ulrike; Cousserans, François; Evans, Jay D; de Miranda, Joachim R; Neumann, Peter

    2015-07-09

    A complete reference genome of the Apis mellifera Filamentous virus (AmFV) was determined using Illumina Hiseq sequencing. The AmFV genome is a double stranded DNA molecule of approximately 498,500 nucleotides with a GC content of 50.8%. It encompasses 247 non-overlapping open reading frames (ORFs), equally distributed on both strands, which cover 65% of the genome. While most of the ORFs lacked threshold sequence alignments to reference protein databases, twenty-eight were found to display significant homologies with proteins present in other large double stranded DNA viruses. Remarkably, 13 ORFs had strong similarity with typical baculovirus domains such as PIFs (per os infectivity factor genes: pif-1, pif-2, pif-3 and p74) and BRO (Baculovirus Repeated Open Reading Frame). The putative AmFV DNA polymerase is of type B, but is only distantly related to those of the baculoviruses. The ORFs encoding proteins involved in nucleotide metabolism had the highest percent identity to viral proteins in GenBank. Other notable features include the presence of several collagen-like, chitin-binding, kinesin and pacifastin domains. Due to the large size of the AmFV genome and the inconsistent affiliation with other large double stranded DNA virus families infecting invertebrates, AmFV may belong to a new virus family.

  20. A full-scale study of mixing and foaming in egg-shaped anaerobic digesters.

    Science.gov (United States)

    Subramanian, Bhargavi; Miot, Alexandre; Jones, Bonnie; Klibert, Corey; Pagilla, Krishna R

    2015-09-01

    Seasonal foaming in full-scale egg-shaped digesters (ESD) at the Oceanside Water Pollution Control Plant was investigated over a two-year period. The causes and contributors of anaerobic digestion (AD) foaming, namely, Gordonia amarae filaments and mixing effects were evaluated in these ESDs. The seasonal presence of high levels of G. amarae as a primary cause and excessive induced mixing as an important contributor of AD foaming has been established. The induced mixing frequency in the ESDs was gradually reduced and eventually shut off in a series of controlled experimental phases. Total solids and temperature profiles indicated that reducing mixing frequency did not significantly impact digester performance or disrupt the homogeneity of digester contents, although it did reduce the occurrence of foam in the digesters. Excessive induced mixing, a contributor to foaming, increased foam events at G. amarae thresholds above 10(6)intersections/mg VSS in the mixed liquor.

  1. Anaerobic digestion foaming in full-scale biogas plants: a survey on causes and solutions.

    Science.gov (United States)

    Kougias, P G; Boe, K; O-Thong, S; Kristensen, L A; Angelidaki, I

    2014-01-01

    Anaerobic digestion foaming is a common operation problem in biogas plants with negative impacts on the biogas plants economy and environment. A survey of 16 Danish full-scale biogas plants on foaming problems revealed that most of them had experienced foaming in their processes up to three times per year. Foaming incidents often lasted from one day to three weeks, causing 20-50% biogas production loss. One foaming case at Lemvig biogas plant has been investigated and the results indicated that the combination of feedstock composition and mixing pattern of the reactor was the main cause of foaming in this case. Moreover, no difference in bacterial communities between the foaming and non-foaming reactors was observed, showing that filamentous bacteria were not the main reason for foaming in this case.

  2. The effect of outside conditions on anaerobic ammonia oxidation reaction

    Institute of Scientific and Technical Information of China (English)

    YANG Min; WANG Shu-bo

    2016-01-01

    Organic carbon, inorganic carbon, temperature, pH and ORP are all to have a certain influence on the anaerobic ammonia oxidation reaction. We can draw some conclusions on the optimum conditions of anaerobic ammonia oxidation reaction. The optimum temperature of the anaerobic ammonia oxidation reaction is 30-35℃. And the optimum pH of the anaerobic ammonia reaction is 7.5-8.3. The presence of organic matters can affect the anaerobic ammonia reaction, and different organic matters have different influence on it. The concentration of the inorganic carbon also exist great influence on the reaction. High inorganic carbon concentration also can inhibit anaerobic ammonia oxidation reaction.

  3. Metabolic interactions between methanogenic consortia and anaerobic respiring bacteria

    DEFF Research Database (Denmark)

    Stams, A.J.; Oude Elferink, S.J.; Westermann, Peter

    2003-01-01

    Most types of anaerobic respiration are able to outcompete methanogenic consortia for common substrates if the respective electron acceptors are present in sufficient amounts. Furthermore, several products or intermediate compounds formed by anaerobic respiring bacteria are toxic to methanogenic...... consortia. Despite the potentially adverse effects, only few inorganic electron acceptors potentially utilizable for anaerobic respiration have been investigated with respect to negative interactions in anaerobic digesters. In this chapter we review competitive and inhibitory interactions between anaerobic...... respiring populations and methanogenic consortia in bioreactors. Due to the few studies in anaerobic digesters, many of our discussions are based upon studies of defined cultures or natural ecosystems...

  4. Measurement of Reversed Extension Flow using the Filament Stretch Rheometer

    DEFF Research Database (Denmark)

    Rasmussen, Henrik K.; Skov, Anne Ladegaard; Nielsen, Jens Kromann;

    2008-01-01

    The measurement of material functions with reversed extension flow is demonstrated using the Filament Stretching Rheometer (FSR). This includes startup of uniaxial elongational flow (potentially until steady state) followed by biaxial squeezing, and large amplitude oscillatory elongation (LAOE). ...

  5. Dynamics of wave fronts and filaments in anisotropic cardiac tissue

    CERN Document Server

    Dierckx, Hans J F M

    2015-01-01

    The heartbeat is mediated between cardiac cells by waves of electrical depolarisation. During cardiac arrhythmias, electrical activity was found to be organised in scroll waves which rotate around a dynamical filament curve. In this thesis, a curved-space approach is used to mathematically capture anisotropy of wave propagation. We derive for the first time the covariant laws of motion for traveling wave fronts and scroll wave filaments in anisotropic excitable media such as cardiac tissue. We show that locally varying anisotropy yields non-zero Riemann tensor components, which may alter the stability of scroll wave filaments. The instability of scroll wave filaments has been linked to transition from ventricular tachycardia to fibrillation.

  6. Actin filaments on myosin beds: The velocity distribution

    Science.gov (United States)

    Bourdieu, L.; Magnasco, M. O.; Winkelmann, D. A.; Libchaber, A.

    1995-12-01

    In vitro studies of actin filaments sliding on a myosin-coated surface are analyzed, filament by filament, at a sampling rate of 30 per second. For each filament, the mean arc length coordinate is computed and histograms of instantaneous velocities, along the arc length, are established. Two types of motion are observed, depending on the experimental conditions. The first one is characterized by a homogeneous flow, with well defined velocities. In this regime, specific defects are a constitutive part of the flow. It is observed at high temperature, at high myosin coverage, and with a particular mode of attachment of myosin to the surface. The second regime shows no clear velocity selection, but a broadband distribution. It is characterized by high friction and is observed at low temperature or low myosin density. (c) 1995 The American Physical Society

  7. Bright Prospect for the Polyester Industrial Filament Sector

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Some large companies from Americaand Europe have constructed plantsin China or established long-termstable cooperation relationship withChinese enterprises. A bright devel-opment prospect has therefore beenbrought to the polyester industrial fila-ment sector in China.

  8. Persistence of strain in motor-filament assemblies

    CERN Document Server

    Gopinath, Arvind; Mahadevan, L

    2015-01-01

    Crosslinked semi-flexible and flexible filaments that are actively deformed by molecular motors occur in various natural settings, such as the ordered eukaryotic flagellum, and the disordered cytoskeleton. The deformation of these composite systems is driven by active motor forces and resisted by passive filament elasticity, and structural constraints due to permanent cross-links. Using a mean field theory for a one-dimensional ordered system, we show that the combination of motor activity and finite filament extensibility yields a characteristic persistence length scale over which active strain decays. This decay length is set by the ability of motors to respond to combination of the weak extensional elasticity, passive shear resistance and the viscoelastic properties of the motor assembly, and generalizes the notion of persistence in purely thermal filaments to active systems.

  9. Collective alignment of polar filaments by molecular motors.

    Science.gov (United States)

    Ziebert, F; Vershinin, M; Gross, S P; Aranson, I S

    2009-04-01

    We study the alignment of polar biofilaments, such as microtubules and actin, subject to the action of multiple molecular motors attached simultaneously to more than one filament. Focusing on a paradigm model of only two filaments interacting with multiple motors, we were able to investigate in detail the alignment dynamics. While almost no alignment occurs in the case of a single motor, the filaments become rapidly aligned due to the collective action of the motors. Our analysis shows that the alignment time is governed by the number of bound motors and the magnitude of the motors' stepping fluctuations. We predict that the time scale of alignment is in the order of seconds, much faster than that reported for passive crosslink-induced bundling. In vitro experiments on the alignment of microtubules by multiple-motor covered beads are in qualitative agreement. We also discuss another mode of fast alignment of filaments, namely the cooperation between motors and passive crosslinks.

  10. Calibration and temperature profile of a tungsten filament lamp

    Energy Technology Data Exchange (ETDEWEB)

    De Izarra, Charles [Groupe de Recherche sur l' Energetique des Milieux Ionises, UMR6606 Universite d' Orleans, CNRS, Faculte des Sciences, Site de Bourges, rue Gaston Berger, BP 4043, 18028 Bourges Cedex (France); Gitton, Jean-Michel, E-mail: Charles.De_Izarra@univ-orleans.f [College Littre, 10 rue Littre, Bourges (France)

    2010-07-15

    The goal of this work proposed for undergraduate students and teachers is the calibration of a tungsten filament lamp from electric measurements that are both simple and precise, allowing to determine the temperature of tungsten filament as a function of the current intensity. This calibration procedure was first applied to a conventional filament lamp (lamp used in automotive lighting) and then tested on a standard tungsten ribbon lamp. The calibration procedure developed was checked by determining the calibration point of the tungsten ribbon lamp with an accuracy of 2%. In addition, for low current intensity, it was observed that the temperature of the filament was not uniform; an explanation is proposed by considering a simple heat transfer model.

  11. Filament propagation length of femtosecond pulses with different transverse modes

    CERN Document Server

    Kaya, N; Kaya, G; Strohaber, J; Kolomenskii, A A; Schuessler, H A

    2014-01-01

    We experimentally studied intense femtosecond pulse filamentation and propagation in water for Gaussian, Laguerre-Gaussian, and Bessel-Gaussian incident beams. These different transverse modes for incident laser pulses were created from an initial Gaussian beam by using a computer generated hologram technique. We found that the length of the filament induced by the Bessel-Gaussian incident beam was longer than that for the other transverse modes under the conditions of the same peak intensity, pulse duration, and the size of the central part of the beam. To better understand the Bessel-Gaussian beam propagation, we performed a more detailed study of the filament length as a function of the number of radial modal lobes. The length increased with the number of lobes, implying that the radial modal lobes serve as an energy reservoir for the filament formed by the central intensity peak.

  12. FILAMENTATION INSTABILITY OF LASER BEAMS IN NONLOCAL NONLINEAR MEDIA

    Institute of Scientific and Technical Information of China (English)

    文双春; 范滇元

    2001-01-01

    The filamentation instability of laser beams propagating in nonlocal nonlinear media is investigated. It is shown that the filamentation instability can occur in weakly nonlocal self-focusing media for any degree of nonlocality, and in defocusing media for the input light intensity exceeding a threshold related to the degree of nonlocality. A linear stability analysis is used to predict the initial growth rate of the instability. It is found that the nonlocality tends to suppress filamentation instability in self-focusing media and to stimulate filamentation instability in self-defocusing media. Numerical simulations confirm the results of the linear stability analysis and disclose a recurrence phenomenon in nonlocal self-focusing media analogous to the Fermi-Pasta-Ulam problem.

  13. Filamentous Phages As a Model System in Soft Matter Physics.

    Science.gov (United States)

    Dogic, Zvonimir

    2016-01-01

    Filamentous phages have unique physical properties, such as uniform particle lengths, that are not found in other model systems of rod-like colloidal particles. Consequently, suspensions of such phages provided powerful model systems that have advanced our understanding of soft matter physics in general and liquid crystals in particular. We described some of these advances. In particular we briefly summarize how suspensions of filamentous phages have provided valuable insight into the field of colloidal liquid crystals. We also describe recent experiments on filamentous phages that have elucidated a robust pathway for assembly of 2D membrane-like materials. Finally, we outline unique structural properties of filamentous phages that have so far remained largely unexplored yet have the potential to further advance soft matter physics and material science.

  14. Elastic response of filamentous networks with compliant crosslinks.

    Science.gov (United States)

    Sharma, A; Sheinman, M; Heidemann, K M; MacKintosh, F C

    2013-11-01

    Experiments have shown that elasticity of disordered filamentous networks with compliant crosslinks is very different from networks with rigid crosslinks. Here, we model and analyze filamentous networks as a collection of randomly oriented rigid filaments connected to each other by flexible crosslinks that are modeled as wormlike chains. For relatively large extensions we allow for enthalpic stretching of crosslink backbones. We show that for sufficiently high crosslink density, the network linear elastic response is affine on the scale of the filaments' length. The nonlinear regime can become highly nonaffine and is characterized by a divergence of the elastic modulus at finite strain. In contrast to the prior predictions, we do not find an asymptotic regime in which the differential elastic modulus scales linearly with the stress, although an approximate linear dependence can be seen in a transition from entropic to enthalpic regimes. We discuss our results in light of recent experiments.

  15. Elastic response of filamentous networks with compliant crosslinks

    CERN Document Server

    Sharma, A; Heidemann, K M; MacKintosh, F C

    2013-01-01

    Experiments have shown that elasticity of disordered filamentous networks with compliant crosslinks is very different from networks with rigid crosslinks. Here, we model and analyze filamentous networks as a collection of randomly oriented rigid filaments connected to each other by flexible crosslinks that are modeled as worm-like chains. For relatively large extensions we allow for enthalpic stretching of crosslinks' backbones. We show that for sufficiently high crosslink density, the network linear elastic response is affine on the scale of the filaments' length. The nonlinear regime can become highly nonaffine and is characterized by a divergence of the elastic modulus at finite strain. In contrast to the prior predictions, we do not find an asymptotic regime in which the differential elastic modulus scales linearly with the stress, although an approximate linear dependence can be seen in a transition from entropic to enthalpic regimes. We discuss our results in light of the recent experiments.

  16. Tropomyosin diffusion over actin subunits facilitates thin filament assembly

    Directory of Open Access Journals (Sweden)

    Stefan Fischer

    2016-01-01

    Full Text Available Coiled-coil tropomyosin binds to consecutive actin-subunits along actin-containing thin filaments. Tropomyosin molecules then polymerize head-to-tail to form cables that wrap helically around the filaments. Little is known about the assembly process that leads to continuous, gap-free tropomyosin cable formation. We propose that tropomyosin molecules diffuse over the actin-filament surface to connect head-to-tail to partners. This possibility is likely because (1 tropomyosin hovers loosely over the actin-filament, thus binding weakly to F-actin and (2 low energy-barriers provide tropomyosin freedom for 1D axial translation on F-actin. We consider that these unique features of the actin-tropomyosin interaction are the basis of tropomyosin cable formation.

  17. Successive filament eruptions within one solar breakout event

    CERN Document Server

    Shen, Yuandeng

    2014-01-01

    The magnetic breakout model has been widely used to explain solar eruptive activities. Here, we apply it to explain successive filament eruptions occurred in a quadrupolar magnetic source region. Based on the high temporal and spatial resolution, multi-wavelengths observations taken by the Atmospheric Imaging Assembly (AIA) on board the Solar Dynamic Observatory (SDO), we find some signatures that support the occurrence of breakout-like external reconnection just before the start of the successive filament eruptions. Furthermore, the extrapolated three-dimensional coronal field also reveals that the magnetic topology above the quadrupolar source region resembles that of the breakout model. We propose a possible mechanism within the framework of the breakout model to interpret the successive filament eruptions, in which the so-called magnetic implosion mechanism is firstly introduced to be the physical linkage of successive filament eruptions. We conclude that the structural properties of coronal fields are im...

  18. Evaluation of filamentous green algae as feedstocks for biofuel production.

    Science.gov (United States)

    Zhang, Wei; Zhao, Yonggang; Cui, Binjie; Wang, Hui; Liu, Tianzhong

    2016-11-01

    Compared with unicellular microalgae, filamentous algae have high resistance to grazer-predation and low-cost recovery in large-scale production. Green algae, as the most diverse group of algae, included numerous filamentous genera and species. In this study, records of filamentous genera and species in green algae were firstly censused and classified. Then, seven filamentous strains subordinated in different genera were cultivated in bubbled-column to investigate their growth rate and energy molecular (lipid and starch) capacity. Four strains including Stigeoclonium sp., Oedogonium nodulosum, Hormidium sp. and Zygnema extenue were screened out due to their robust growth. And they all could accumulate triacylglycerols and starch in their biomass, but with different capacity. After nitrogen starvation, Hormidium sp. and Oedogonium nodulosum respectively exhibited high capacity of lipid (45.38% in dry weight) and starch (46.19% in dry weight) accumulation, which could be of high potential as feedstocks for biodiesel and bioethanol production.

  19. The comparison study of diagnostics of light filaments in air

    Institute of Scientific and Technical Information of China (English)

    HAO; Zuoqiang; ZHANG; Jie; YU; Jin; ZHENG; Zhiyuan; YUAN; Xiaohui; ZHANG; Zhe; LI; Yutong; WANG; Zhaohua; LING; Weijun; WEI; Zhiyi

    2006-01-01

    Long plasma channels in air induced by femtosecond laser pulses are investigated using three different methods, including the cross-section imaging, resistivity measuring and acoustic diagnostics. These methods are based on different properties of the light filaments. A comparison of the three diagnostics shows that the imaging method is the most precise one in studying the filaments distribution and evolution, that the sonographic method is the most convenient approach to detecting long plasma channels by detecting the acoustic wave generation, and that the resistivity measurement can only be applied for giving a rough estimate. The diagnostics of filaments allow us to choose appropriate detecting methods and provide further insight into the dynamic evolution of the light filaments in air.

  20. Spin alignment of dark matter haloes in filaments and walls

    CERN Document Server

    Arag'on-Calvo, M A; Jones, B J T; Van der Hulst, T; Arag\\'on-Calvo, Miguel A.; Weygaert, Rien van de; Jones, Bernard J. T.

    2006-01-01

    The MMF technique is used to segment the cosmic web as seen in a cosmological N-body simulation into wall-like and filament-like structures. We find that the spins and shapes of dark matter haloes are significantly correlated with each other and with the orientation of their host structures. The shape orientation is such that the halo minor axes tend to lie perpendicular to the host structure, be it a wall or filament. The orientation of the halo spin vector is mass dependent. Low mass haloes in walls and filaments have a tendency to have their spins oriented within the parent structure, while higher mass haloes in filaments have spins that tend to lie perpendicular to the parent structure.

  1. Tropomyosin diffusion over actin subunits facilitates thin filament assembly

    Science.gov (United States)

    Fischer, Stefan; Rynkiewicz, Michael J.; Moore, Jeffrey R.; Lehman, William

    2016-01-01

    Coiled-coil tropomyosin binds to consecutive actin-subunits along actin-containing thin filaments. Tropomyosin molecules then polymerize head-to-tail to form cables that wrap helically around the filaments. Little is known about the assembly process that leads to continuous, gap-free tropomyosin cable formation. We propose that tropomyosin molecules diffuse over the actin-filament surface to connect head-to-tail to partners. This possibility is likely because (1) tropomyosin hovers loosely over the actin-filament, thus binding weakly to F-actin and (2) low energy-barriers provide tropomyosin freedom for 1D axial translation on F-actin. We consider that these unique features of the actin-tropomyosin interaction are the basis of tropomyosin cable formation. PMID:26798831

  2. Current Situations of Edible Fungus Production in Lianyungang City and Development Countermeasures

    Institute of Scientific and Technical Information of China (English)

    LI Guan-xi; GE Xiong-can; WEI Liang-zhi

    2012-01-01

    On the basis of characteristics of edible fungus production in Lianyungang City, we analyzed its advantages and disadvantages and put forward suggestions and countermeasures for development of edible fungus industry, mainly including strengthening guidance and leadership of government, introducing professional personnel, and developing the edible fungus industry through science and technology.

  3. Nucleus-associated intermediate filaments from chicken erythrocytes

    OpenAIRE

    1980-01-01

    Chicken erythrocyte nuclei prepared by isolation in isotonic KCl and Nonidet P-40 detergent were found to contain numerous attached filaments with a mean diameter of 11.0 nm. In polypeptide content and solubility properties, they resembled the vimentin type of intermediate filament found in cells of mesenchymal origin. Examination of their association with the nucleus suggests that more than a simple membrane attachment is involved.

  4. Scrape Off Layer profiles interpreted with filament dynamics

    CERN Document Server

    Militello, F

    2016-01-01

    A theoretical framework is developed to link the density profiles in the Scrape Off Layer (SOL) with the fluctuations (filaments) that generate them. The framework is based on the dynamics of independent filaments and their statistical behaviour and can be used to rigorously understand the mechanisms that lead to flattening and broadening of the SOL profiles as well as the radial increase of the relative fluctuation amplitude.

  5. Motility patterns of filamentous sulfur bacteria, Beggiatoa spp

    DEFF Research Database (Denmark)

    Dunker, Rita; Røy, Hans; Kamp, Anja;

    2011-01-01

    was constructed based on our observations. The model was applied to virtual filaments in the oxygen- and sulfide-free zone of the sediment, which is a main habitat of Beggiatoa in the natural environment. The model predicts a long residence time of the virtual filament in the suboxic zone and explains why...... Beggiatoa accumulate high nitrate concentrations in internal vacuoles as an alternative electron acceptor to oxygen....

  6. Scrape off layer profiles interpreted with filament dynamics

    Science.gov (United States)

    Militello, F.; Omotani, J. T.

    2016-10-01

    A theoretical framework is developed to link the density profiles in the scrape off layer (SOL) with the fluctuations (filaments) that generate them. The framework is based on the dynamics of independent filaments and their statistical behaviour and can be used to rigorously understand the mechanisms that lead to flattening and broadening of the SOL profiles as well as the radial increase of the relative fluctuation amplitude.

  7. Complete genome sequence of the filamentous anoxygenic phototrophic bacterium Chloroflexus aurantiacus

    Directory of Open Access Journals (Sweden)

    Larimer Frank W

    2011-06-01

    Full Text Available Abstract Background Chloroflexus aurantiacus is a thermophilic filamentous anoxygenic phototrophic (FAP bacterium, and can grow phototrophically under anaerobic conditions or chemotrophically under aerobic and dark conditions. According to 16S rRNA analysis, Chloroflexi species are the earliest branching bacteria capable of photosynthesis, and Cfl. aurantiacus has been long regarded as a key organism to resolve the obscurity of the origin and early evolution of photosynthesis. Cfl. aurantiacus contains a chimeric photosystem that comprises some characters of green sulfur bacteria and purple photosynthetic bacteria, and also has some unique electron transport proteins compared to other photosynthetic bacteria. Methods The complete genomic sequence of Cfl. aurantiacus has been determined, analyzed and compared to the genomes of other photosynthetic bacteria. Results Abundant genomic evidence suggests that there have been numerous gene adaptations/replacements in Cfl. aurantiacus to facilitate life under both anaerobic and aerobic conditions, including duplicate genes and gene clusters for the alternative complex III (ACIII, auracyanin and NADH:quinone oxidoreductase; and several aerobic/anaerobic enzyme pairs in central carbon metabolism and tetrapyrroles and nucleic acids biosynthesis. Overall, genomic information is consistent with a high tolerance for oxygen that has been reported in the growth of Cfl. aurantiacus. Genes for the chimeric photosystem, photosynthetic electron transport chain, the 3-hydroxypropionate autotrophic carbon fixation cycle, CO2-anaplerotic pathways, glyoxylate cycle, and sulfur reduction pathway are present. The central carbon metabolism and sulfur assimilation pathways in Cfl. aurantiacus are discussed. Some features of the Cfl. aurantiacus genome are compared with those of the Roseiflexus castenholzii genome. Roseiflexus castenholzii is a recently characterized FAP bacterium and phylogenetically closely related to Cfl

  8. ANAEROBIC BIOLOGICAL TREATMENT OF PRODUCED WATER

    Energy Technology Data Exchange (ETDEWEB)

    John R. Gallagher

    2001-07-31

    During the production of oil and gas, large amounts of water are brought to the surface and must be disposed of in an environmentally sensitive manner. This is an especially difficult problem in offshore production facilities where space is a major constraint. The chief regulatory criterion for produced water is oil and grease. Most facilities have little trouble meeting this criterion using conventional oil-water separation technologies. However, some operations have significant amounts of naphthenic acids in the water that behave as oil and grease but are not well removed by conventional technologies. Aerobic biological treatment of naphthenic acids in simulated-produced water has been demonstrated by others; however, the system was easily overloaded by the large amounts of low-molecular-weight organic acids often found in produced waters. The objective of this research was to determine the ability of an anaerobic biological system to treat these organic acids in a simulated produced water and to examine the potential for biodegradation of the naphthenic acids in the anaerobic environment. A small fixed-film anaerobic biological reactor was constructed and adapted to treat a simulated produced water. The bioreactor was tubular, with a low-density porous glass packing material. The inocula to the reactor was sediment from a produced-water holding pond from a municipal anaerobic digester and two salt-loving methanogenic bacteria. During start-up, the feed to the reactor contained glucose as well as typical produced-water components. When glucose was used, rapid gas production was observed. However, when glucose was eliminated and the major organic component was acetate, little gas was generated. Methane production from acetate may have been inhibited by the high salt concentrations, by sulfide, or because of the lack, despite seeding, of microbes capable of converting acetate to methane. Toluene, a minor component of the produced water (0.1 g/L) was removed in the

  9. Large scale filaments associated with Milky Way spiral arms

    CERN Document Server

    Wang, Ke; Ginsburg, Adam; Walmsley, C Malcolm; Molinari, Sergio; Schisano, Eugenio

    2015-01-01

    The ubiquity of filamentary structure at various scales through out the Galaxy has triggered a renewed interest in their formation, evolution, and role in star formation. The largest filaments can reach up to Galactic scale as part of the spiral arm structure. However, such large scale filaments are hard to identify systematically due to limitations in identifying methodology (i.e., as extinction features). We present a new approach to directly search for the largest, coldest, and densest filaments in the Galaxy, making use of sensitive Herschel Hi-GAL data complemented by spectral line cubes. We present a sample of the 9 most prominent Herschel filaments, including 6 identified from a pilot search field plus 3 from outside the field. These filaments measure 37-99 pc long and 0.6-3.0 pc wide with masses (0.5-8.3)$\\times10^4 \\, M_\\odot$, and beam-averaged ($28"$, or 0.4-0.7 pc) peak H$_2$ column densities of (1.7-9.3)$\\times 10^{22} \\, \\rm{cm^{-2}}$. The bulk of the filaments are relatively cold (17-21 K), whi...

  10. Formation of a solar Ha filament from orphan penumbrae

    CERN Document Server

    Buehler, D; van Noort, M; Solanki, S K

    2016-01-01

    The formation of an Ha filament in active region (AR) 10953 is described. Observations from the Solar Optical Telescope (SOT) aboard the Hinode satellite starting on 27th April 2007 until 1st May 2007 were analysed. 20 scans of the 6302A Fe I line pair recorded by SOT/SP were inverted using the SPINOR code. The inversions were analysed together with SOT/BFI G-band and Ca II H and SOT/NFI Ha observations. Following the disappearance of an initial Ha filament aligned along the polarity inversion line (PIL) of the AR, a new Ha filament formed in its place some 20 hours later, which remained stable for at least 1.5 days. The creation of the new Ha filament was driven by the ascent of horizontal magnetic fields from the photosphere into the chromosphere at three separate locations along the PIL. The magnetic fields at two of these locations were situated directly underneath the initial Ha filament and formed orphan penumbrae already aligned along the Ha filament channel. The 700 G orphan penumbrae were stable and ...

  11. The interaction of a magnetohydrodynamical shock with a filament

    CERN Document Server

    Goldsmith, K J A

    2016-01-01

    We present 3D magnetohydrodynamic numerical simulations of the adiabatic interaction of a shock with a dense, filamentary cloud. We investigate the effects of various filament lengths and orientations on the interaction using different orientations of the magnetic field, and vary the Mach number of the shock, the density contrast of the filament, and the plasma beta, in order to determine their effect on the evolution and lifetime of the filament. We find that in a parallel magnetic field filaments have longer lifetimes if they are orientated more 'broadside' to the shock front, and that an increase in the density contrast hastens the destruction of the cloud, in terms of the modified cloud-crushing time-scale, tcs. The combination of a mild shock and a perpendicular or oblique field provides the best condition for extending the life of the filament, with some filaments able to survive almost indefinitely since they are cocooned by the magnetic field. A high value for the density contrast does not initiate la...

  12. SDC13 infrared dark clouds: Longitudinally collapsing filaments?

    CERN Document Server

    Peretto, N; André, Ph; Arzoumanian, D; Rivilla, V M; Bardeau, S; Puertas, S Duarte; Fernandez, J P Guzman; Lenfestey, C; Li, G -X; Olguin, F A; Röck, B R; de Villiers, H; Williams, J

    2013-01-01

    Formation of stars is now believed to be tightly linked to the dynamical evolution of interstellar filaments in which they form. In this paper we analyze the density structure and kinematics of a small network of infrared dark filaments, SDC13, observed in both dust continuum and molecular line emission with the IRAM 30m telescope. These observations reveal the presence of 18 compact sources amongst which the two most massive, MM1 and MM2, are located at the intersection point of the parsec-long filaments. The dense gas velocity and velocity dispersion observed along these filaments show smooth, strongly correlated, gradients. We discuss the origin of the SDC13 velocity field in the context of filament longitudinal collapse. We show that the collapse timescale of the SDC13 filaments (from 1 Myr to 4 Myr depending on the model parameters) is consistent with the presence of Class I sources in them, and argue that, on top of bringing more material to the centre of the system, collapse could generate additional k...

  13. Properties of Cosmological Filaments extracted from Eulerian Simulations

    CERN Document Server

    Gheller, Claudio; Favre, Jean; Brüggen, Marcus

    2015-01-01

    Using a new parallel algorithm implemented within the VisIt framework, we analysed large cosmological grid simulations to study the properties of baryons in filaments. The procedure allows us to build large catalogues with up to $\\sim 3 \\cdot 10^4$ filaments per simulated volume and to investigate the properties of cosmic filaments for very large volumes at high resolution (up to $300^3 ~\\rm Mpc^3$ simulated with $2048^3$ cells). We determined scaling relations for the mass, volume, length and temperature of filaments and compared them to those of galaxy clusters. The longest filaments have a total length of about $200 ~\\rm Mpc$ with a mass of several $10^{15} M_{\\odot}$. We also investigated the effects of different gas physics. Radiative cooling significantly modifies the thermal properties of the warm-hot-intergalactic medium of filaments, mainly by lowering their mean temperature via line cooling. On the other hand, powerful feedback from active galactic nuclei in surrounding halos can heat up the gas in ...

  14. Appearance of Dusty Filaments at Different Viewing Angles

    CERN Document Server

    Chira, R -A; Henning, Th; Kainulainen, J

    2016-01-01

    Context: In the last years, there have been many studies on the omnipresence and structures of filaments in star-forming regions, as well as their role in the process of star formation. Those filaments are normally identified as elongated fibres across the plane of the sky. But how would we detect filaments that are inclined? Aims: We aim to learn more about whether, and how, total column density or dust temperature change with respect to the line of sight. Such variations would enable observers to use dust observations to identify and study filaments at any inclination and gain more insight on the distribution and orientations of filaments within the Galactic plane. Methods: As a first step, we perform numerical calculations on simple cylindrical models to evaluate the influence of filament geometry on the average flux density. After that, we apply our three-dimensional Monte Carlo dust radiative transfer code on two models of star-forming regions and derive maps of effective total column density and dust te...

  15. Topology of magnetic helicity of torsioned filaments in Hall plasmas

    CERN Document Server

    de Andrade, L C Garcia

    2007-01-01

    A solution of magnetic Hall equations for plasma filaments in the Coulomb gauge is obtained in the non-holonomic frame. Some physical features of the solution include, the non-conservation of the magnetic helicity and the decay of the magnetic field in the filaments. From the mathematical point of view,the presence of Frenet torsion in the filament is actually shown to be fundamental for the breaking of conservation of magnetic helicity in the case of helicoidal filaments. Since the magnetic helicity is not conserved even in the Coulomb gauge, and the magnetic field decays, one can say that the dynamo action fails. Actually the presence of torsion enhances the breaking of magnetic field helicity conservation. A similar formula of the one obtained here without considering the Hall effect has been obtained by Moffatt and Ricca (PRSA-1992) in the case of holonomic filaments. It is shown that unknotted magnetic filaments may place a lower bound on the magnetic energy. Discussions on the writhe number are also dis...

  16. The Hβ Chromospheric Magnetic Field in a Quiescent Filament

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    We observed the line-of-sight magnetic field in the chromosphereandphotosphere of a large quiescent filament on the solar disk on September 6, 2001using the Solar Magnetic Field Telescope in Huairou Solar Observing Station. Thechromospheric and photospheric magnetograms together with Hβ filtergrams of thefilament were examined. The filament was located on the neutral line of the largescale longitudinal magnetic field in the photosphere and the chromosphere. Thelateral feet of the filament .were found to be related to magnetic structures with op-posite polarities. Two small lateral feet are linked to weak parasitic polarity. Thereis a negative magnetic structure in the photosphere under a break of the filament.At the location corresponding to the filament in the chromospheric magnetograms,the magnetic strength is found to be about 40-70 Gauss (measuring error about 39Gauss). The magnetic signal indicates the amplitude and orientation of the internalmagnetic field in the filament. We discuss several possible causes which may pro-duce such a measured signal. A twisted magnetic configuration inside the filamentis suggested .

  17. Sympathetic Solar Filament Eruptions on 2015 March 15

    CERN Document Server

    Wang, Rui; Zimovets, Ivan; Hu, Huidong; Dai, Xinghua; Yang, Zhongwei

    2016-01-01

    The 2015 March 15 coronal mass ejection as one of the two that together drove the largest geomagnetic storm of solar cycle 24 so far was associated with sympathetic filament eruptions. We investigate the relations between the different filaments involved in the eruption. A surge-like small-scale filament motion is confirmed as the trigger that initiated the erupting filament with multi-wavelength observations and using a forced magnetic field extrapolation method. When the erupting filament moved to an open magnetic field region, it experienced an obvious acceleration process and was accompanied by a C-class flare and the rise of another larger filament that eventually failed to erupt. We measure the decay index of the background magnetic field, which presents a critical height of 118 Mm. Combining with a potential field source surface extrapolation method, we analyze the distributions of the large-scale magnetic field, which indicates that the open magnetic field region may provide a favorable condition for ...

  18. Force-velocity measurements of a few growing actin filaments.

    Directory of Open Access Journals (Sweden)

    Coraline Brangbour

    2011-04-01

    Full Text Available The polymerization of actin in filaments generates forces that play a pivotal role in many cellular processes. We introduce a novel technique to determine the force-velocity relation when a few independent anchored filaments grow between magnetic colloidal particles. When a magnetic field is applied, the colloidal particles assemble into chains under controlled loading or spacing. As the filaments elongate, the beads separate, allowing the force-velocity curve to be precisely measured. In the widely accepted Brownian ratchet model, the transduced force is associated with the slowing down of the on-rate polymerization. Unexpectedly, in our experiments, filaments are shown to grow at the same rate as when they are free in solution. However, as they elongate, filaments are more confined in the interspace between beads. Higher repulsive forces result from this higher confinement, which is associated with a lower entropy. In this mechanism, the production of force is not controlled by the polymerization rate, but is a consequence of the restriction of filaments' orientational fluctuations at their attachment point.

  19. Force-Velocity Measurements of a Few Growing Actin Filaments

    Science.gov (United States)

    Brangbour, Coraline; du Roure, Olivia; Helfer, Emmanuèle; Démoulin, Damien; Mazurier, Alexis; Fermigier, Marc; Carlier, Marie-France; Bibette, Jérôme; Baudry, Jean

    2011-01-01

    The polymerization of actin in filaments generates forces that play a pivotal role in many cellular processes. We introduce a novel technique to determine the force-velocity relation when a few independent anchored filaments grow between magnetic colloidal particles. When a magnetic field is applied, the colloidal particles assemble into chains under controlled loading or spacing. As the filaments elongate, the beads separate, allowing the force-velocity curve to be precisely measured. In the widely accepted Brownian ratchet model, the transduced force is associated with the slowing down of the on-rate polymerization. Unexpectedly, in our experiments, filaments are shown to grow at the same rate as when they are free in solution. However, as they elongate, filaments are more confined in the interspace between beads. Higher repulsive forces result from this higher confinement, which is associated with a lower entropy. In this mechanism, the production of force is not controlled by the polymerization rate, but is a consequence of the restriction of filaments' orientational fluctuations at their attachment point. PMID:21541364

  20. Filament Fragmentation in High-Mass Star Formation

    CERN Document Server

    Beuther, H; Johnston, K; Henning, Th; Hacar, A; Kainulainen, J T

    2015-01-01

    Aims: We resolve the length-scales for filament formation and fragmentation (res. <=0.1pc), in particular the Jeans length and cylinder fragmentation scale. Methods: We observed the prototypical high-mass star-forming filament IRDC18223 with the Plateau de Bure Interferometer (PdBI) in the 3.2mm continuum and N2H+(1-0) line emission in a ten field mosaic at a spatial resolution of ~4'' (~14000AU). Results: The dust continuum emission resolves the filament into a chain of at least 12 relatively regularly spaced cores. The mean separation between cores is ~0.40(+-0.18)pc. While this is approximately consistent with the fragmentation of an infinite, isothermal, gravitationally bound gas cylinder, a high mass-to-length ratio of M/l~1000M_sun/pc requires additional turbulent and/or magnetic support against radial collapse of the filament. The N2H+(1-0) data reveal a velocity gradient perpendicular to the main filament. Although rotation of the filament cannot be excluded, the data are also consistent with the m...