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

    Penttilä Merja


    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

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


    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.




    An anaerobic fungus was isolated from Hama faeces. Based on its morphological characteristics, polyflagellated zoospores, extensive rhizoid system and the formation of monocentric colonies, the fungus is assigned to the genus Neocallimastix. Neocallimastix sp. L2 is able to grow on several poly-, ol

  4. Solubilization of lignin by the ruminal anaerobic fungus Neocallimastix patriciarum.

    McSweeney, C S; Dulieu, A; Katayama, Y; Lowry, J B


    The ability of the ruminal anaerobic phycomycete Neocallimastix patriciarum to digest model lignin compounds and lignified structures in plant material was studied in batch culture. The fungus did not degrade or transform model lignin compounds that were representative of the predominant intermonomer linkages in lignin, nor did it solubilize acid detergent lignin that had been isolated from spear grass. In a stem fraction of sorghum, 33.6% of lignin was apparently solubilized by the fungus. S...

  5. Engineering a filamentous fungus for L-rhamnose extraction.

    Kuivanen, Joosu; Richard, Peter


    L-Rhamnose is a high value rare sugar that is used as such or after chemical conversions. It is enriched in several biomass fractions such as the pectic polysaccharides rhamnogalacturonan I and II and in naringin, hesperidin, rutin, quercitrin and ulvan. We engineered the filamentous fungus Aspergillus niger to not consume L-rhamnose, while it is still able to produce the enzymes for the hydrolysis of L-rhamnose rich biomass. As a result we present a strain that can be used for the extraction of L-rhamnose in a consolidated process. In the process the biomass is hydrolysed to the monomeric sugars which are consumed by the fungus leaving the L-rhamnose. PMID:27033543

  6. Engineering a filamentous fungus for l-rhamnose extraction

    Kuivanen, Joosu; Richard, Peter


    l-Rhamnose is a high value rare sugar that is used as such or after chemical conversions. It is enriched in several biomass fractions such as the pectic polysaccharides rhamnogalacturonan I and II and in naringin, hesperidin, rutin, quercitrin and ulvan. We engineered the filamentous fungus Aspergillus niger to not consume l-rhamnose, while it is still able to produce the enzymes for the hydrolysis of l-rhamnose rich biomass. As a result we present a strain that can be used for the extraction...

  7. Directed evolution of a filamentous fungus for thermotolerance

    Lyons Thomas J


    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

  8. Fitness-associated sexual reproduction in a filamentous fungus.

    Schoustra, Sijmen; Rundle, Howard D; Dali, Rola; Kassen, Rees


    Sex is a long-standing evolutionary enigma. Although the majority of eukaryotes reproduce sexually at least sometimes [1-3], the evolution of sex from an asexual ancestor has been difficult to explain because it requires sexually reproducing lineages to overcome the manifold costs of sex, including the destruction of favorable gene combinations created by selection [4, 5]. Conditions for the evolution of sex are much broader if individuals can reproduce either sexually or asexually (i.e., facultative sex) and allocate disproportionately more resources to sex when their fitness is low (fitness-associated-sex or FAS [6-10]). Although facultatively sexual organisms have been shown to engage in more sex when stressed [11], direct evidence for FAS is lacking. We provide evidence using 53 genotypes of the filamentous fungus Aspergillus nidulans in a reciprocal transplant experiment across three environments. Different genotypes achieved highest fitness in different environments and genotypes invested relatively more in sex in environments in which their fitness was lower, showing that allocation to sexual reproduction is a function of how well-adapted a genotype is to its environment. FAS in A. nidulans is unlikely to have evolved as a strategy to resist or avoid stress because asexual spores are more dispersive and equally resistant [12, 13]. PMID:20598542

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

    Jørgensen, Mikael Skaanning

    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 in...

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

    Penttilä Merja


    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.

  11. The Role of Cross Pathway Control-2 (cpc-2) in Filamentous Fungus Neurospora Crassa

    Garud, Amruta Vikas


    In the filamentous fungus Neurospora crassa, heterotrimeric G protein pathways are major signaling cascades through which the fungus senses and adapts to its environment. The characterized Gβ subunit of N. crassa, GNB-1, has seven tryptophan-aspartate (WD) repeats, predicted to result in a β propeller structure. Another related N. crassa protein, called Cross Pathway Control-2 (CPC-2), also has a seven WD repeat structure and possesses 70% positional identity with Receptor for Activ...

  12. Solubilization of diabase and phonolite dust by filamentous fungus

    Juliana Andréia Vrba Brandão


    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.

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

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


    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...

  14. Lactose enhances cellulase production by the filamentous fungus Acremonium cellulolyticus.

    Fang, Xu; Yano, Shinichi; Inoue, Hiroyuki; Sawayama, Shigeki


    Acremonium cellulolyticus is a fungus that produces cellulase and has been exploited by enzyme industry. To promote cellulase production by A. cellulolyticus strain C-1, we evaluated the effects of the saccharides: Solka Floc (cellulose), soluble soybean polysaccharide (SSPS), pullulan, lactose, trehalose, sophorose, cellobiose, galactose, sorbose, lactobionic acid, and mixtures as carbon sources for cellulase production. Solka Floc with SSPS enhanced cellulase production. Lactose as the sole carbon source induced cellulase synthesis in this fungus, and the synergistic effects between lactose and Solka Floc was observed. Various enzyme activities and the protein composition of crude enzyme produced by cultures with or without addition of lactose were analyzed. The results showed that lactose addition greatly improves the production of various proteins with cellulase activity by A. cellulolyticus. To our knowledge, this is the first report on production of cellulases by lactose in the A. cellulolyticus. PMID:18804052

  15. Deciphering the molecular mechanisms behind cellulase production in Trichoderma reesei, the hyper-cellulolytic filamentous fungus.

    Shida, Yosuke; Furukawa, Takanori; Ogasawara, Wataru


    The filamentous fungus Trichoderma reesei is a potent cellulase producer and the best-studied cellulolytic fungus. A lot of investigations not only on glycoside hydrolases produced by T. reesei, but also on the machinery controlling gene expression of these enzyme have made this fungus a model organism for cellulolytic fungi. We have investigated the T. reesei strain including mutants developed in Japan in detail to understand the molecular mechanisms that control the cellulase gene expression, the biochemical and morphological aspects that could favor this phenotype, and have attempted to generate novel strains that may be appropriate for industrial use. Subsequently, we developed recombinant strains by combination of these insights and the heterologous-efficient saccharifing enzymes. Resulting enzyme preparations were highly effective for saccharification of various biomass. In this review, we present some of the salient findings from the recent biochemical, morphological, and molecular analyses of this remarkable cellulase hyper-producing fungus. PMID:27075508

  16. The cell wall of the filamentous fungus Aspergillus niger

    Damveld, Robbert A.


    Fungi are a very successful species and are distributed worldwide. However, the presence of fungi is not always desired. Filamentous fungi can grow on living or dead organic material and even inside the host. Current methods to prevent fungal growth are insufficient, causing fatality after fungal in

  17. Protein secretion in the filamentous fungus Aspergillus niger

    Weenink, Xavier Oswin


    Filamentous fungi are multicellular eukaryotic organisms, which represent a separate taxonomic group organisms within the fungal kingdom, apart from the yeasts. These fungi always need a substrate to grow on, this can be living or dead material. Fungi possess the capacity to secrete high levels of enzymes. Because of this specific property, fungi are already used for centuries as miniature factories for the production of extracellular proteins. Aspergillus niger is an attractive organism beca...

  18. A new anaerobic fungus (Oontomyces anksri gen. nov., sp. nov.) from the digestive tract of the Indian camel (Camelus dromedarius).

    Dagar, Sumit S; Kumar, Sanjay; Griffith, Gareth W; Edwards, Joan E; Callaghan, Tony M; Singh, Rameshwar; Nagpal, Ashok K; Puniya, Anil K


    Two cultures of anaerobic fungi were isolated from the forestomach of an Indian camel (Camelus dromedarius). Phylogenetic analysis using both the internal transcribed spacer (ITS) and large-subunit (LSU) regions of the rRNA locus demonstrated that these isolates were identical and formed a distinct clade within the anaerobic fungi (phylum Neocallimastigomycota). Morphological examination showed that these fungi formed monocentric thalli with filamentous rhizoids and uniflagellate zoospores, broadly similar to members of the genus Piromyces. However, distinctive morphological features were observed, notably the pinching of the cytoplasm in the sporangiophore and the formation of intercalary rhizoidal swellings. Since genetic analyses demonstrated this fungus was only distantly related to Piromyces spp. and closer to the polycentric Anaeromyces clade, we have assigned it to a new genus and species Oontomyces anksri gen. nov., sp. nov. Interrogation of the GenBank database identified several closely related ITS sequences, which were all environmental sequences obtained from camels, raising the possibility that this fungus may be specific to camelids. PMID:26228561

  19. Vacuolar Membrane Dynamics in the Filamentous Fungus Aspergillus oryzae†

    Shoji, Jun-ya; Arioka, Manabu; Kitamoto, Katsuhiko


    Vacuoles in filamentous fungi are highly pleomorphic and some of them, e.g., tubular vacuoles, are implicated in intra- and intercellular transport. In this report, we isolated Aovam3, the homologue of the Saccharomyces cerevisiae VAM3 gene that encodes the vacuolar syntaxin, from Aspergillus oryzae. In yeast complementation analyses, the expression of Aovam3 restored the phenotypes of both Δvam3 and Δpep12 mutants, suggesting that AoVam3p is likely the vacuolar and/or endosomal syntaxin in A...

  20. Identification of microRNA-Like RNAs in the Filamentous Fungus Trichoderma reesei by Solexa Sequencing

    Kang, Kang; Zhong, Jiasheng; Jiang, Liang; Liu, Gang; Gou, Christine Yuan; Wu, Qiong; Wang, You; Luo, Jun; Gou, Deming


    microRNAs (miRNAs) are non-coding small RNAs (sRNAs) capable of negatively regulating gene expression. Recently, microRNA-like small RNAs (milRNAs) were discovered in several filamentous fungi but not yet in Trichoderma reesei, an industrial filamentous fungus that can secrete abundant hydrolases. To explore the presence of milRNA in T. reesei and evaluate their expression under induction of cellulose, two T. reesei sRNA libraries of cellulose induction (IN) and non-induction (CON) were gener...

  1. Gene cluster involved in melanin biosynthesis of the filamentous fungus Alternaria alternata.

    N. Kimura; Tsuge,T.


    The filamentous fungus Alternaria alternata produces melanin, a black pigment, from acetate via 1,8-dihydroxynaphthalene. To isolate a fungal gene required for melanin biosynthesis, we transformed an A. alternata Brm1- (light brown) mutant with the DNA of a wild-type strain genomic library constructed by use of a cosmid carrying the hygromycin B phosphotransferase gene. When hygromycin B-resistant transformants were screened for melanin production, 1 of 1,363 transformants appeared to regain ...

  2. Defining individual size in the model filamentous fungus Neurospora crassa.

    Ma, Linda; Song, Boya; Curran, Thomas; Phong, Nhu; Dressaire, Emilie; Roper, Marcus


    It is challenging to apply the tenets of individuality to filamentous fungi: a fungal mycelium can contain millions of genetically diverse but totipotent nuclei, each capable of founding new mycelia. Moreover, a single mycelium can potentially stretch over kilometres, and it is unlikely that its distant parts share resources or have the same fitness. Here, we directly measure how a single mycelium of the model ascomycete Neurospora crassa is patterned into reproductive units (RUs), meaning subpopulations of nuclei that propagate together as spores, and function as reproductive individuals. The density of RUs is sensitive to the geometry of growth; we detected 50-fold smaller RUs when mycelia had expanding frontiers than when they were constrained to grow in one direction only. RUs fragmented further when the mycelial network was perturbed. In mycelia with expanding frontiers, RU composition was strongly influenced by the distribution of genotypes early in development. Our results provide a concept of fungal individuality that is directly connected to reproductive potential, and therefore to theories of how fungal individuals adapt and evolve over time. Our data show that the size of reproductive individuals is a dynamic and environment-dependent property, even within apparently totally connected fungal mycelia. PMID:26962146

  3. Cellophane based mini-prep method for DNA extraction from the filamentous fungus Trichoderma reesei

    Henrique-Silva Flavio


    Full Text Available Abstract Background Methods for the extraction of DNA from filamentous fungi are frequently laborious and time consuming because most of the available protocols include maceration in liquid nitrogen after the mycelium has been grown in a liquid culture. This paper describes a new method to replace those steps, which involves the growth of the mycelium on cellophane disks overlaid on solid medium and the use of glass beads for cell wall disruption. Results Extractions carried out by this method provided approximately 2 μg of total DNA per cellophane disk for the filamentous fungus Trichoderma reesei. To assess the DNA's quality, we made a PCR (Polymerase Chain Reaction amplification of a gene introduced by a transformation in this fungus's genome (hph gene, with successful results. We also confirmed the quality of the DNA by the use of Southern blotting to analyze the presence of the same gene, which was easily detected, resulting in a sharply defined and strong band. Conclusions The use of this method enabled us to obtain pure DNA from Trichoderma reesei, dispensing with the laborious and time-consuming steps involved in most protocols. The DNA obtained was found to be suitable for PCR and Southern blot analyses. Another advantage of this method is the fact that several samples can be processed simultaneously, growing the fungus on multiple well cell culture plates. In addition, the absence of maceration also reduces sample handling, minimizing the risks of contamination, a particularly important factor in work involving PCR.

  4. Live Cell Imaging of Actin Dynamics in the Filamentous Fungus Aspergillus nidulans.

    Schultzhaus, Zachary; Quintanilla, Laura; Hilton, Angelyn; Shaw, Brian D


    Hyphal cells of filamentous fungi grow at their tips in a method analogous to pollen tube and root hair elongation. This process, generally referred to as tip growth, requires precise regulation of the actin cytoskeleton, and characterizing the various actin structures in these cell types is currently an active area of research. Here, the actin marker Lifeact was used to document actin dynamics in the filamentous fungus Aspergillus nidulans. Contractile double rings were observed at septa, and annular clusters of puncta were seen subtending growing hyphal tips, corresponding to the well-characterized subapical endocytic collar. However, Lifeact also revealed two additional structures. One, an apical array, was dynamic on the face opposite the tip, while a subapical web was dynamic on the apical face and was located several microns behind the growth site. Each was observed turning into the other over time, implying that they could represent different localizations of the same structure, although hyphae with a subapical web grew faster than those exhibiting an apical array. The subapical web has not been documented in any filamentous fungus to date, and is separate from the networks of F-actin seen in other tip-growing organisms surrounding septa or stationary along the plasmalemma. PMID:26879694

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

    Chen Chun-Long


    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

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

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


    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.

  7. Special properties of polycentric anaerobic fungus Anaeromyces mucronatus

    Fliegerová, Kateřina; Pažoutová, Sylvie; Mrázek, Jakub; Kopečný, Jan


    Roč. 71, - (2002), s. 441-444. ISSN 0001-7213 R&D Projects: GA AV ČR KSK5020115; GA ČR GA523/96/0103; GA AV ČR KSK5052113 Keywords : rumen * fungi * anaerobic Subject RIV: ED - Physiology Impact factor: 0.370, year: 2002

  8. Buwchfawromyces eastonii gen. nov., sp. nov.: a new anaerobic fungus (Neocallimastigomycota isolated from buffalo faeces

    Tony Martin Callaghan


    Full Text Available The novel anaerobic fungus Buwchfawromyces eastonii gen. nov., sp. nov., belonging to order Neocallimastigales (phylum Neocallimastigomycota is described. Morphologically similar to Piromyces but genetically quite distinct, this fungus (isolate GE09 was first isolated from buffalo faeces in west Wales and then subsequently isolated from sheep, cattle and horse in the same area. Phylogenetic analysis of LSU and ITS sequence confirmed that B. eastonii isolates formed a distinct clade close to the polycentric Anaeromyces spp. The morphology of GE09 is monocentric with monoflagellate zoospores. However, the sporangial stalk (sporangiophore is often distinctly swollen and the proximal regions of the rhizoidal system twisted in appearance.

  9. Identification and characterization of genes required for hyphal morphogenesis in the filamentous fungus Aspergillus nidulans.

    Harris, S D; Hofmann, A F; Tedford, H W; Lee, M.P.


    In the filamentous fungus Aspergillus nidulans, germination of an asexual conidiospore results in the formation of a hyphal cell. A key feature of spore germination is the switch from isotropic spore expansion to polarized apical growth. Here, temperature-sensitive mutations are used to characterize the roles of five genes (sepA, hypA, podB-podD) in the establishment and maintenance of hyphal polarity. Evidence that suggests that the hypA, podB, and sepA genes are required for multiple aspect...

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

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


    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. PMID:26891354

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

    Wasserstrom, Lisa

    , which is regulated by the pheromone response pathway. Most ascomycetes have been reported to produce meiotic spores, however, a sexual cycle has not yet been identified in the filamentous fungus Ashbya gossypii. The main focus of my doctoral thesis has therefore been to understand the mechanisms behind...... remains unidentified. In this thesis I provide a comprehensive functional analysis of genes important for sporulation in A. gossypii. Previous results, together with findings presented in this work show that the role of the pheromone response pathway in A. gossypii has been rewired to regulate sporulation...... recombination that allows cross-over between homologous chromosomes. In S. cerevisiae, this requires double strand break (DSB) formation and subsequent repair via the components Spo11 and Dmc1. The work in this thesis show that the A. gossypii Spo11 and Dmc1 homologs are not required for sporulation, thus...

  12. Regulation of cellulase gene expression in the filamentous fungus Trichoderma reesei.

    Ilmén, M; Saloheimo, A; Onnela, M L; Penttilä, M E


    Basic features of regulation of expression of the genes encoding the cellulases of the filamentous fungus Trichoderma reesei QM9414, the genes cbh1 and cbh2 encoding cellobiohydrolases and the genes egl1, egl2 and egl5 encoding endoglucanases, were studied at the mRNA level. The cellulase genes were coordinately expressed under all conditions studied, with the steady-state mRNA levels of cbh1 being the highest. Solka floc cellulose and the disaccharide sophorose induced expression to almost the same level. Moderate expression was observed when cellobiose or lactose was used as the carbon source. It was found that glycerol and sorbitol do not promote expression but, unlike glucose, do not inhibit it either, because the addition of 1 to 2 mM sophorose to glycerol or sorbitol cultures provokes high cellulase expression levels. These carbon sources thus provide a useful means to study cellulase regulation without significantly affecting the growth of the fungus. RNA slot blot experiments showed that no expression could be observed on glucose-containing medium and that high glucose levels abolish the inducing effect of sophorose. The results clearly show that distinct and clear-cut mechanisms of induction and glucose repression regulate cellulase expression in an actively growing fungus. However, derepression of cellulase expression occurs without apparent addition of an inducer once glucose has been depleted from the medium. This expression seems not to arise simply from starvation, since the lack of carbon or nitrogen as such is not sufficient to trigger significant expression. PMID:9097427

  13. Production of α-Amylase by the Ruminal Anaerobic Fungus Neocallimastix frontalis

    Mountfort, Douglas O.; Asher, Rodney A.


    α-Amylase production was examined in the ruminal anaerobic fungus Neocallimastix frontalis. The enzyme was released mainly into the culture fluid and had temperature and pH optima of 55°C and 5.5, respectively, and the apparent Km for starch was 0.8 mg ml−1. The products of α-amylase action were mainly maltotriose, maltotetraose, and longer-chain oligosaccharides. No activity of the enzyme was observed towards these compounds or pullulan, but activity on amylose was similar to starch. Evidenc...

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

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


    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. PMID:17541536

  15. Molecular analysis of the anaerobic rumen fungus Orpinomyces - insights into an AT-rich genome.

    Nicholson, Matthew J; Theodorou, Michael K; Brookman, Jayne L


    The anaerobic gut fungi occupy a unique niche in the intestinal tract of large herbivorous animals and are thought to act as primary colonizers of plant material during digestion. They are the only known obligately anaerobic fungi but molecular analysis of this group has been hampered by difficulties in their culture and manipulation, and by their extremely high A+T nucleotide content. This study begins to answer some of the fundamental questions about the structure and organization of the anaerobic gut fungal genome. Directed plasmid libraries using genomic DNA digested with highly or moderately rich AT-specific restriction enzymes (VspI and EcoRI) were prepared from a polycentric Orpinomyces isolate. Clones were sequenced from these libraries and the breadth of genomic inserts, both genic and intergenic, was characterized. Genes encoding numerous functions not previously characterized for these fungi were identified, including cytoskeletal, secretory pathway and transporter genes. A peptidase gene with no introns and having sequence similarity to a gene encoding a bacterial peptidase was also identified, extending the range of metabolic enzymes resulting from apparent trans-kingdom transfer from bacteria to fungi, as previously characterized largely for genes encoding plant-degrading enzymes. This paper presents the first thorough analysis of the genic, intergenic and rDNA regions of a variety of genomic segments from an anaerobic gut fungus and provides observations on rules governing intron boundaries, the codon biases observed with different types of genes, and the sequence of only the second anaerobic gut fungal promoter reported. Large numbers of retrotransposon sequences of different types were found and the authors speculate on the possible consequences of any such transposon activity in the genome. The coding sequences identified included several orphan gene sequences, including one with regions strongly suggestive of structural proteins such as collagens

  16. Localization of RHO-4 Indicates Differential Regulation of Conidial versus Vegetative Septation in the Filamentous Fungus Neurospora crassa▿ †

    Rasmussen, Carolyn G.; Glass, N. Louise


    rho-4 mutants of the filamentous fungus Neurospora crassa lack septa and asexual spores (conidia) and grow slowly. In this report, localization of green fluorescent protein-tagged RHO-4 is used to elucidate the differences in factors controlling RHO-4 localization during vegetative growth versus asexual development. RHO-4 forms a ring at incipient vegetative septation sites that constricts with the formation of the septum toward the septal pore; RHO-4 persists around the septal pore after sep...

  17. Identification of residues important for substrate uptake in a glucose transporter from the filamentous fungus Trichoderma reesei

    Weixin Zhang; Yanli Cao; Jing Gong; Xiaoming Bao; Guanjun Chen; Weifeng Liu


    The glucose transporter is an important player in cell metabolism that mediates the intracellular uptake of glucose. Here, we characterized the glucose transporter Stp1 from the filamentous fungus Trichoderma reesei. The individual substitution of several conserved residues for Ala in Stp1 corresponding to those interacting with D-glucose in the xylose/H+ symporter XylE inflicted contrasting effects on its ability to support the growth of an hxt-null yeast on glucose. The targeted change of P...

  18. Bioaccumulation and biosorption of bismuth Bi (III) by filamentous fungus Aspergillus clavatus

    In this work we focused on bismuth (III) biosorption and bioaccumulation. Prior the bioaccumulation experiments the 7-day-old conidia were collected from mycelia surface of filamentous fungus Aspergillus clavatus and used as inocula for 50 ml of nutrient media with different bismuth (III) concentrations. After 15-day cultivation under laboratory conditions (dark, 25 grad C) the bismuth concentration in grown fungal biomass was measured using ICP OES. Maximum achieved accumulation capacity of dry biomass was 112 μmol.g-1. Batch biosorption experiments were performed in Erlenmeyer flasks with pelletized wet fungal biomass/solution ratio 1.8% and with various bismuth (III) concentrations. The equilibrium time was studied within the time interval of 0-240 min. The reaction kinetics were well described by both pseudo-first and pseudo-second order rate models, and equilibrium was reached after 50 min. Langmuir and Freundlich isotherm models were used to represent equilibrium data, and the calculated maximum biosorption capacity of fungal biomass for bismuth(III) was 0.40 mmol.g-1. (authors)

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

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


    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. PMID:26927228

  20. 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

    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...

  1. The hydrogenosomal malic enzyme from the anaerobic fungus Neocallimastix frontalis is targeted to mitochondria of the methylotrophic yeast Hansenula polymorpha

    van der Giezen, M; Kiel, J.A.K.W.; Sjollema, K.A; Prins, R.A


    Hydrogenosomal proteins always contain an amino-terminal extension which is believed to be a hydrogenosomal targeting signal. In the anaerobic fungus Neocallimastix frontalis these putative targeting signals are 27 amino acids long, are enriched in Ala, Leu, Ser and Arg, and have an Arg at position

  2. The phenotype of a phospholipase C (plc-1) mutant in a filamentous fungus, Neurospora crassa.

    Lew, Roger R; Giblon, Rachel E; Lorenti, Miranda S H


    In the filamentous fungus Neurospora crassa, phospholipase C may play a role in hyphal extension at the growing tips as part of a growth-sensing mechanism that activates calcium release from internal stores to mediate continued expansion of the hyphal tip. One candidate for a tip-localized phospholipase C is PLC-1. We characterized morphology and growth characteristics of a knockout mutant (KO plc-1) and a RIP mutated strain (RIP plc-1) (missense mutations and a nonsense mutation render the gene product non-functional). Growth and hyphal cytology of wildtype and KO plc-1 were similar, but the RIP plc-1 mutant grew slower and exhibited abnormal membrane structures at the hyphal tip, imaged using the fluorescence dye FM4-64. To test for causes of the slower growth of the RIP plc-1 mutant, we examined its physiological poise compared to wildtype and the KO plc-1 mutant. The electrical properties of all three strains and the electrogenic contribution of the plasma membrane H(+)-ATPase (identified by cyanide inhibition) were the same. Responses to high osmolarity were also similar. However, the RIP plc-1 mutant had a significantly lower turgor, a possible cause of its slower growth. While growth of all three strains was inhibited by the phospholipase C inhibitor 3-nitrocoumarin, the RIP plc-1 mutant did not exhibit hyphal bursting after addition of the inhibitor, observed in both wildtype and the KO plc-1 mutant. Although the plc-1 gene is not obligatory for tip growth, the phenotype of the RIP plc-1 mutant - abnormal tip cytology, lower turgor and resistance to inhibitor-induced hyphal bursting - suggest it does play a role in tip growth. The expression of a dysfunctional plc-1 gene may cause a shift to alternative mechanism(s) of growth sensing in hyphal extension. PMID:26212074

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

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


    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.

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

    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...

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

    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.

  6. Hydrophilins in the filamentous fungus Neosartorya fischeri (Aspergillus fischeri) have protective activity against several types of microbial water stress.

    van Leeuwen, M R; Wyatt, T T; van Doorn, T M; Lugones, L G; Wösten, H A B; Dijksterhuis, J


    Hydrophilins are proteins that occur in all domains of life and protect cells and organisms against drought and other stresses. They include most of the late embryogenesis abundant (LEA) proteins and the heat shock protein (HSP) Hsp12. Here, the role of a predicted LEA-like protein (LeamA) and two Hsp12 proteins (Hsp12A and Hsp12B) of Neosartorya fischeri was studied. This filamentous fungus forms ascospores that belong to the most stress-resistant eukaryotic cells described to date. Heterologous expression of LeamA, Hsp12A and Hsp12B resulted in increased tolerance against salt and osmotic stress in Escherichia coli. These proteins were also shown to protect lactate dehydrogenase against dry heat and freeze-thaw cycles in vitro. Deletion of leamA caused diminished viability of sexual ascospores after drought and heat. This is the first report on functionality of Hsp12 and putative LeamA proteins derived from filamentous fungi, and their possible role in N. fischeri ascospore resistance against desiccation, high temperature and osmotic stress is discussed. PMID:26487515

  7. AoRim15 is involved in conidial stress tolerance, conidiation and sclerotia formation in the filamentous fungus Aspergillus oryzae.

    Nakamura, Hidetoshi; Kikuma, Takashi; Jin, Feng Jie; Maruyama, Jun-Ichi; Kitamoto, Katsuhiko


    The serine-threonine kinase Rim15p is a master regulator of stress signaling and is required for stress tolerance and sexual sporulation in the yeast Saccharomyces cerevisiae. However, in filamentous fungi that reproduce asexually via conidiation, the physiological function of Rim15p homologs has not been extensively analyzed. Here, we functionally characterized the protein homolog of Rim15p in the filamentous fungus Aspergillus oryzae, by deleting and overexpressing the corresponding Aorim15 gene and examining the role of this protein in stress tolerance and development. Deletion of Aorim15 resulted in an increase in the sensitivity of conidia to oxidative and heat stresses, whereas conidia of the Aorim15 overexpressing strain were more resistant to these stresses. These results indicated that AoRim15 functions in stress tolerance, similar to S. cerevisiae Rim15p. Phenotypic analysis revealed that conidiation was markedly reduced by overexpression of Aorim15 in A. oryzae, and was completely abolished in the deletion strain. In addition, the formation of sclerotia, which is another type of developmental structure in filamentous fungi, was decreased by the deletion of Aorim15, whereas Aorim15 overexpression increased the number of sclerotia. These results indicated that AoRim15 is a positive regulator of sclerotia formation and that overexpression of AoRim15 shifts the developmental balance from conidiation towards sclerotia formation. Collectively, we demonstrated that AoRim15 is involved in the stress tolerance of conidia and differentially regulates between the two developmental fates of conidiation and sclerotia formation. PMID:26467693

  8. Endocytosis Is Crucial for Cell Polarity and Apical Membrane Recycling in the Filamentous Fungus Aspergillus oryzae▿

    Higuchi, Yujiro; Shoji, Jun-ya; Arioka, Manabu; Kitamoto, Katsuhiko


    Establishing the occurrence of endocytosis in filamentous fungi was elusive in the past mainly due to the lack of reliable indicators of endocytosis. Recently, however, it was shown that the fluorescent dye N-(3-triethylammoniumpropyl)-4-(p-diethyl-aminophenyl-hexatrienyl)pyridinium dibromide (FM4-64) and the plasma membrane protein AoUapC (Aspergillus oryzae UapC) fused to enhanced green fluorescent protein (EGFP) were internalized from the plasma membrane by endocytosis. Although the occurr...

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

    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


    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. PMID:24811710

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

    Anna eBergs


    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.

  11. Dynamics of Actin Cables in Polarized Growth of the Filamentous Fungus Aspergillus nidulans

    Bergs, Anna; Ishitsuka, Yuji; Evangelinos, Minoas; Nienhaus, G. U.; Takeshita, Norio


    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 have been developed to visualize actin cables in filamentous fungi, the exact organization and dynamics of actin cables has remained elusive. Here, we observed actin cables using tropomyosin (TpmA) and Lifeact fused to fluorescent proteins in living Aspergillus nidulans hyphae 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.

  12. 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

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


    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

  13. Identification of residues important for substrate uptake in a glucose transporter from the filamentous fungus Trichoderma reesei.

    Zhang, Weixin; Cao, Yanli; Gong, Jing; Bao, Xiaoming; Chen, Guanjun; Liu, Weifeng


    The glucose transporter is an important player in cell metabolism that mediates the intracellular uptake of glucose. Here, we characterized the glucose transporter Stp1 from the filamentous fungus Trichoderma reesei. The individual substitution of several conserved residues for Ala in Stp1 corresponding to those interacting with D-glucose in the xylose/H(+) symporter XylE inflicted contrasting effects on its ability to support the growth of an hxt-null yeast on glucose. The targeted change of Phe 50, proximal to the substrate-binding site, was also found to exert a profound effect on the activity of Stp1. In contrast with the charged residues, the substitution of Phe 50 with either the hydrophilic residues Asn and Gln or the small residues Gly and Ala significantly enhanced the transport of glucose and its fluorescent analogue, 2-NBDG. On the other hand, a variant with the three substitutions I115F, F199I and P214L displayed remarkably improved activity on glucose and 2-NBDG transport. Further analysis indicated that the combined mutations of Ile 115 and Pro 214, positioned on the lateral surface of the Stp1 N-domain, fully accounted for the enhanced transport activity. These results provide insight into the structural basis for glucose uptake in fungal sugar transporters. PMID:26345619

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

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


    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 (anaerobic fungus for improving the digestibility of lignocellulose substrates for biogas and biohydrogen production. PMID:25755016

  15. Sequences of stilboflavin C: towards the peptaibiome of the filamentous fungus Stilbella (= Trichoderma) flavipes.

    Degenkolb, Thomas; Götze, Lutz; von Döhren, Hans; Vilcinskas, Andreas; Brückner, Hans


    Filamentous fungi of the genus Stilbella are recognized as an abundant source of naturally occurring α-aminoisobutyric acid-containing peptides. The culture broth of Stilbella (Trichoderma) flavipes CBS 146.81 yielded a mixture of peptides named stilboflavins (SF), and these were isolated and separated by preparative TLC into groups named SF-A, SF-B, and SF-C. Although all three of these groups resolved as single spots on thin-layer chromatograms, HPLC analysis revealed that each of the groups represents very microheterogeneous mixtures of closely related peptides. Here, we report on the sequence analysis of SF-C peptides, formerly isolated by preparative TLC. HPLC coupled to QqTOF-ESI-HRMS provided the sequences of 10 16-residue peptides and five 19-residue peptides, all of which were N-terminally acetylated. In contrast to the previously described SF-A and SF-B peptaibols, SF-C peptaibols contain Ser-Alaol or Ser-Leuol, which are rarely found as C-termini, and repetitive Leu-Aib-Gly sequences, which have not been detected in peptaibols before. Taking the previously determined sequences of SF-A and SF-B into account, the entirety of peptides produced by S. flavipes (the 'peptaibiome') approaches or exceeds 100 non-ribosomally biosynthesized peptaibiotics. Copyright © 2016 European Peptide Society and John Wiley & Sons, Ltd. PMID:27443977

  16. Aspergillus tubingensis: a major filamentous fungus found in the airways of patients with lung disease.

    Gautier, Magali; Normand, Anne-Cécile; L'Ollivier, Coralie; Cassagne, Carole; Reynaud-Gaubert, Martine; Dubus, Jean-Christophe; Brégeon, Fabienne; Hendrickx, Marijke; Gomez, Carine; Ranque, Stéphane; Piarroux, Renaud


    The black Aspergillus group comprises A. niger and 18 other species, which are morphologically indistinguishable. Among this species subset, A. tubingensis, described in less than 30 human cases before 2014, is primarily isolated from ear, nose, and throat samples. Recently, matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has emerged as a powerful technique to identify microbes in diagnostic settings. We applied this method to identify 1,720 filamentous fungi routinely isolated from clinical samples our laboratory over a two-year study period. Accordingly, we found 85 isolates of A. niger, 58 of A. tubingensis, and six other black Aspergillus (4 A. carbonarius and 2 A. japonicus). A. tubingensis was the fifth most frequent mold isolated in our mycology laboratory, primarily isolated from respiratory samples (40/58 isolates). In this study, we mainly aimed to describe the clinical pattern of Aspergillus tubingensisWe analyzed the clinical features of the patients in whom A. tubingensis had been isolated from 40 respiratory samples. Thirty patients suffered from cystic fibrosis, chronic obstructive pulmonary disease or other types of chronic respiratory failure. Strikingly, 20 patients were experiencing respiratory acute exacerbation at the time the sample was collected. Antifungal susceptibility testing of 36 A. tubingensis isolates showed lower amphotericin B MICs (P cystic fibrosis and chronic pulmonary diseases. PMID:26773134

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

    Stocchi Vilberto


    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

  18. Sulphur metabolism and cellulase gene expression are connected processes in the filamentous fungus Hypocrea jecorina (anamorph Trichoderma reesei

    Schmoll Monika


    Full Text Available Abstract Background Sulphur compounds like cysteine, methionine and S-adenosylmethionine are essential for the viability of most cells. Thus many organisms have developed a complex regulatory circuit that governs the expression of enzymes involved in sulphur assimilation and metabolism. In the filamentous fungus Hypocrea jecorina (anamorph Trichoderma reesei little is known about the participants in this circuit. Results Analyses of proteins binding to the cellulase activating element (CAE within the promotor of the cellobiohydrolase cbh2 gene led to the identification of a putative E3 ubiquitin ligase protein named LIMPET (LIM1, which is an orthologue of the sulphur regulators SCON-2 of Neurospora crassa and Met30p of Saccharomyces cerevisiae. Transcription of lim1 is specifically up-regulated upon sulphur limitation and responds to cellulase inducing conditions. In addition, light dependent stimulation/shut down of cellulase gene transcription by methionine in the presence of sulphate was observed. Further, lim1 transcriptionally reacts to a switch from constant darkness to constant light and is subject to regulation by the light regulatory protein ENVOY. Thus lim1, despite its function in sulphur metabolite repression, responds both to light as well as sulphur- and carbon source. Upon growth on cellulose, the uptake of sulphate is dependent on the light status and essential for growth in light. Unlike other fungi, growth of H. jecorina is not inhibited by selenate under low sulphur conditions, suggesting altered regulation of sulphur metabolism. Phylogenetic analysis of the five sulphate permeases found in the genome of H. jecorina revealed that the predominantly mycelial sulphate permease is lacking, thus supporting this hypothesis. Conclusion Our data indicate that the significance of the sulphate/methionine-related signal with respect to cellulase gene expression is dependent on the light status and reaches beyond detection of sulphur

  19. Degradation of slime extracellular polymeric substances and inhibited sludge flocs destruction contribute to sludge dewaterability enhancement during fungal treatment of sludge using filamentous fungus Mucor sp. GY-1.

    Wang, Zhenyu; Zheng, Guanyu; Zhou, Lixiang


    Mechanisms responsible for the sludge dewaterability enhanced by filamentous fungi during fungal treatment of sludge were investigated in the present study. The filamentous fungus Mucor sp. GY-1, isolated from waste activated sludge, enhanced sludge dewaterability by 82.1% to achieve the lowest value of normalized sludge specific resistance to filtration (SRF), 8.18 × 10(10) m · L/kg · g-TSS. During the fungal treatment of sludge, 57.8% of slime extracellular polymeric substances (EPS) and 51.1% of polysaccharide in slime EPS were degraded, respectively, by Mucor sp. GY-1, contributing to the improvement of sludge dewaterability. Slime EPS is much more available for Mucor sp. GY-1 than either LB-EPS or TB-EPS that bound with microbial cells. In addition, filamentous fungus Mucor sp. GY-1 entrapped small sludge particles and inhibited the destruction of sludge flocs larger than 100 μm, thus enhancing sludge dewaterability, during fungal treatment of sludge using Mucor sp. GY-1. PMID:26086084

  20. A mannanase, ManA, of the polycentric anaerobic fungus Orpinomyces sp. strain PC-2 has carbohydrate binding and docking modules.

    Ximenes, Eduardo A; Chen, Huizhong; Kataeva, Irina A; Cotta, Michael A; Felix, Carlos R; Ljungdahl, Lars G; Li, Xin-Liang


    The anaerobic fungus Orpinomyces sp. strain PC-2 produces a broad spectrum of glycoside hydrolases, most of which are components of a high molecular mass cellulosomal complex. Here we report about a cDNA (manA) having 1924 bp isolated from the fungus and found to encode a polypeptide of 579 amino acid residues. Analysis of the deduced sequence revealed that it had a mannanase catalytic module, a family 1 carbohydrate-binding module, and a noncatalytic docking module. The catalytic module was homologous to aerobic fungal mannanases belonging to family 5 glycoside hydrolases, but unrelated to the previously isolated mannanases (family 26) of the anaerobic fungus Piromyces. No mannanase activity could be detected in Escherichia coli harboring a manA-containing plasmid. The manA was expressed in Saccharomyces cerevisiae and ManA was secreted into the culture medium in multiple forms. The purified extracellular heterologous mannanase hydrolyzed several types of mannan but lacked activity against cellulose, chitin, or beta-glucan. The enzyme had high specific activity toward locust bean mannan and an extremely broad pH profile. It was stable for several hours at 50 degrees C, but was rapidly inactivated at 60 degrees C. The carbohydrate-binding module of the Man A produced separately in E. coli bound preferably to insoluble lignocellulosic substrates, suggesting that it might play an important role in the complex enzyme system of the fungus for lignocellulose degradation. PMID:16175204

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

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


    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...

  2. Properties of a recombinant beta-glucosidase from polycentric anaerobic fungus Orpinomyces PC-2 and its application for cellulose hydrolysis.

    Li, Xin-Liang; Ljungdahl, Lars G; Ximenes, Eduardo A; Chen, Huizhong; Felix, Carlos R; Cotta, Michael A; Dien, Bruce S


    A beta-glucosidase (BglA, EC gene from the polycentric anaerobic fungus Orpinomyces PC-2 was cloned and sequenced. The enzyme containing 657 amino acid residues was homologous to certain animal, plant, and bacterial beta-glucosidases but lacked significant similarity to those from aerobic fungi. Neither cellulose- nor protein-binding domains were found in BglA. When expressed in Saccharomyces cerevisiae, the enzyme was secreted in two forms with masses of about 110 kDa and also found in two forms associated with the yeast cells. Km and Vmax values of the secreted BglA were 0.762 mM and 8.20 micromol/(min x mg), respectively, with p-nitrophenyl-beta-D-glucopyranoside (pNPG) as the substrate and 0.310 mM and 6.45 micromol/(, respectively, for the hydrolysis of cellobiose. Glucose competitively inhibited the hydrolysis of pNPG with a Ki of 3.6 mM. Beta-glucosidase significantly enhanced the conversion of cellulosic materials into glucose by Trichoderma reesei cellulase preparations, demonstrating its potential for use in biofuel and feedstock chemical production. PMID:15054209

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

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


    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. PMID:25795450

  4. Three-dimensional image analysis of plugging at the septal pore by Woronin body during hypotonic shock inducing hyphal tip bursting in the filamentous fungus Aspergillus oryzae

    We observed that the filamentous fungus, Aspergillus oryzae, grown on agar media burst out cytoplasmic constituents from the hyphal tip soon after flooding with water. Woronin body is a specialized organelle known to plug the septal pore adjacent to the lysed compartment to prevent extensive loss of cytoplasm. A. oryzae Aohex1 gene homologous to Neurospora crassa HEX1 gene encoding a major protein in Woronin body was expressed as a fusion with DsRed2, resulting in visualization of Woronin body. Confocal microscopy and three-dimensional reconstruction of images visualized the septal pore as a dark region surrounded by green fluorescence of EGFP-fused secretory protein, RNase T1, on the septum. Dual fluorescent labeling revealed the plugging of the septal pores adjacent to the lysed apical compartments by Woronin bodies during hypotonic shock. Disruption of Aohex1 gene caused disappearance of Woronin bodies and the defect to prevent extensive loss of cytoplasm during hypotonic shock

  5. 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

    Cebula Patricia


    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.

  6. A cyclophilin from the polycentric anaerobic rumen fungus Orpinomyces sp. strain PC-2 is highly homologous to vertebrate cyclophilin B

    Chen, H.; Li, X.L.; Ljungdahl, L.G. [Univ. of Georgia, Athens, GA (United States)


    A cyclophilin (CyP) purified to homogeneity from the polycentric anaerobic rumen fungus Orpinomyces sp. strain PC-2 had a molecular mass of 20.5 kDa and a pI of 8.1. The protein catalyzed the isomerization of the prolyl peptide bond of N-succinyl-Ala-Ala-(cis,trans)-Pro-Phe p-nitroanilide with a k{sub cat}/K{sub m} value of 9.3 x 10{sup 6} M{sup {minus}1}{center_dot}s{sup {minus}1} at 10{degrees}C and pH 7.8. Cyclosporin A strongly inhibited this peptidylprolyl cis-trans isomerase activity with an IC{sub 50} of 19.6 nM. The sequence of the first 30 N-terminal amino acids of this CyP had high homology with the N-terminal sequences of other eukaryotic CyPs. By use of a DNA hybridization probe amplified by PCR with degenerate oligonucleotide primers designed based on the amino acid sequences of the N terminus of this CyP and highly conserved internal regions of other CyPs, a full-length cDNA clone was isolated. It possessed an open reading frame encoding a polypeptide of 203 amino acids with a calculated molecular weight of 21,969, containing a putative hydrophobic signal peptide sequence of 22 amino acids preceding the N terminus of the mature enzyme and a C-terminal sequence, Lys-Ala-Glu-Leu, characteristic of an endoplasmic reticulum retention signal. The Orpinomyces PC-2 CyP is a typical type B CyP. The amino acid sequence of the Orpinomyces CyP exhibits striking degrees of identity with the corresponding human (70%), bovine (69%), mouse (68%), chicken (66%), maize (61%), and yeast (54%) proteins. Phylogenetic analysis based on the CyP sequences indicated that the evolutionary origin of the Orpinomyces CyP was closely related with CyPs of animals. 51 refs., 3 figs., 2 tabs.

  7. A semi-continuous culture system for production of cellulolytic and xylanolytic enzymes by the anaerobic fungus Piromyces sp. strain E2

    Teunissen, M.J.; Baerends, R.J.S.; Knelissen, R.A.G.; Camp, H.J.M. op den; Vogels, G.D. (Katholieke Univ., Nijmegen (Netherlands). Dept. of Microbiology)


    A system was developed for the semi-continous cultivation of an anaerobic fungus, Piromyces sp. strain E2 (isolated from an Indian elephant), on Avicel (microcrystalline cellulose). The fungus was grown in a semi-continuous culture system: Solids and fungal biomass was retained by means of a simple filter construction whereas the culture fluid was removed continuously. The production of fermentation products (acetate, ethanol, formate, lactate, hydrogen or methane), cellulolytic and xylanolytic enzymes, and protein by the fungus in monoculture or co-culture with Methanobacterium formicicum during growth on Avicel was monitored up to 45 days. These productions stabilized after an adaptation period of 24 and 30 days in the semi-continuous co-culture and monoculture, respectively. After this period the average ([+-]SD) avicelase, [beta]-glucosidase, endoglucanase, and xylanase production in the semicontinuous monoculture were 27[+-]6, 140[+-]16, 1057[+-]120 and 5012[+-]583 IUxl[sup -1]xday[sup -1], respectively. Co-culture with the methanogen caused a shift in fermentation products to more acetate, and less ethanol and lactate. Furthermore, the production of all cellulolytic enzymes increased (40%) and xylanolytic enzyme production decreased (35%). (orig.).

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

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


    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.

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

    Rui eZhang


    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.

  10. Biodegradation of 4-n-nonylphenol by the non-ligninolytic filamentous fungus Gliocephalotrichum simplex: A proposal of a metabolic pathway

    4-Nonylphenols (NPs) are endocrine disrupting compounds (EDCs) which are known to interfere with the endocrine system of humans and animals. The aim of this study was to test the ability of non-ligninolytic filamentous fungus Gliocephalotrichum simplex to biodegrade 4-n-NP. The results revealed that during the first 24 h of incubation, 4-n-NP at the concentration of 50 mg L-1 was eliminated from the culture medium by 88%, whereas at the concentration of 100 mg L-1 by 50%. In this paper, glucose utilization as a co-substrate during toxic compound degradation was also shown. It was found that the presence of 4-n-NP caused sugar metabolism retardation and this inhibition was dependent on NP concentration. The qualitative GC-MS analysis showed the presence of products of G. simplex 4-n-NP biodegradation. We proposed the metabolic pathway of 4-n-NP biodegradation, which is based on subsequent C1 removals from the alkyl chain followed by the aromatic ring cleavage. In further experiments with 4-n-NP [ring-14C(U)] we proved aromatic ring cleavage occurrence. After 72 h of incubation the evolution of 14CO2 was observed and the mineralization efficiency was on the level of 29%. The results suggest the existence of a novel mechanism of 4-n-NP degradation in fungi.

  11. Effects of carbon source on expression of alcohol oxidase activity and on morphologic pattern of YR-1 Strain, a filamentous fungus isolated from petroleum-contaminated soils.

    Robelo, Carmen Rodríguez; Novoa, Vanesa Zazueta; Zazueta-Sandoval, Roberto


    Soluble alcohol oxidase (AO) activity was detected in the supernatant fraction of a high-speed centrifugation procedure after ballistic cellular homo-genization to break the mycelium from a filamentous fungus strain named YR-1, isolated from petroleum-contaminated soils. AO activity from aerobically grown mycelium was detected in growth media containing different carbon sources, including alcohols and hydrocarbons but not in glucose. In previous work, zymogram analysis conducted with crude extracts from aerobic mycelium of YR-1 strain indicated the existence of two AO enzymes originally named AO-1 and AO-2. In the present study, we were able to separate the AO-1 band into two bands depending on culture conditions, carbon source, and polyacrylamide gel electrophoresis (PAGE) separation conditions; the enzyme activity pattern in zymograms from cell-free extracts exhibited three different bands after native PAGE. New nomenclature was used for upper bands AO-1 and AO-2 and lower band AO-3, respectively. The expression of AO activity was studied in the absence of glucose in the culture media and in the presence of hydrocarbons or petroleum as sole carbon source, suggesting that AO expression could be subjected to two regulatory possibilities: carbon catabolite regulation by glucose and induction by hydrocarbons. The possibility of catabolic inhibition of AO by glucose in the active enzyme was also tested, and the results confirm that this kind of regulatory mechanism is not present in AO activity. PMID:15054203

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

    Alexandru Manoliu


    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 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.

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

    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

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

    Claudinéia Conationi da Silva Franco


    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.

  15. Three-dimensional structure of a thermostable native cellobiohydrolase, CBH IB, and molecular characterization of the cel7 gene from the filamentous fungus, Talaromyces emersonii.

    Grassick, Alice; Murray, Patrick G; Thompson, Roisin; Collins, Catherine M; Byrnes, Lucy; Birrane, Gabriel; Higgins, Timothy M; Tuohy, Maria G


    The X-ray structure of native cellobiohydrolase IB (CBH IB) from the filamentous fungus Talaromyces emersonii, PDB 1Q9H, was solved to 2.4 A by molecular replacement. 1Q9H is a glycoprotein that consists of a large, single domain with dimensions of approximately 60 A x 40 A x 50 A and an overall beta-sandwich structure, the characteristic fold of Family 7 glycosyl hydrolases (GH7). It is the first structure of a native glycoprotein and cellulase from this thermophilic eukaryote. The long cellulose-binding tunnel seen in GH7 Cel7A from Trichoderma reesei is conserved in 1Q9H, as are the catalytic residues. As a result of deletions and other changes in loop regions, the binding and catalytic properties of T. emersonii 1Q9H are different. The gene (cel7) encoding CBH IB was isolated from T. emersonii and expressed heterologously with an N-terminal polyHis-tag, in Escherichia coli. The deduced amino acid sequence of cel7 is homologous to fungal cellobiohydrolases in GH7. The recombinant cellobiohydrolase was virtually inactive against methylumberiferyl-cellobioside and chloronitrophenyl-lactoside, but partial activity could be restored after refolding of the urea-denatured enzyme. Profiles of cel7 expression in T. emersonii, investigated by Northern blot analysis, revealed that expression is regulated at the transcriptional level. Putative regulatory element consensus sequences for cellulase transcription factors have been identified in the upstream region of the cel7 genomic sequence. PMID:15560790

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

    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.

  17. The pcz1 Gene, which Encodes a Zn(II)2Cys6 Protein, Is Involved in the Control of Growth, Conidiation, and Conidial Germination in the Filamentous Fungus Penicillium roqueforti

    Carlos Gil-Durán; Juan F Rojas-Aedo; Exequiel Medina; Inmaculada Vaca; Ramón O García-Rico; Sebastián Villagrán; Gloria Levicán; Renato Chávez


    Proteins containing Zn(II)(2)Cys(6) domains are exclusively found in fungi and yeasts. Genes encoding this class of proteins are broadly distributed in fungi, but few of them have been functionally characterized. In this work, we have characterized a gene from the filamentous fungus Penicillium roqueforti that encodes a Zn(II)(2)Cys(6) protein, whose function to date remains unknown. We have named this gene pcz1. We showed that the expression of pcz1 is negatively regulated in a P. roqueforti...

  18. 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

    Bruggeman, J.


    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, modular organism, auxotrophic.Chapter 1: IntroductionThe selection arena hypothesis states that overproduction of zygotes -a widespread phenomenon in animals and plants- could be explained as part of a quality control mechanism: An enlarged array of zygotes is ...

  19. Draft Genome Sequence of the Deep-Sea Ascomycetous Filamentous Fungus Cadophora malorum Mo12 from the Mid-Atlantic Ridge Reveals Its Biotechnological Potential

    Rédou, Vanessa; Kumar, Abhishek; Hainaut, Matthieu; Henrissat, Bernard; Record, Eric; Barbier, Georges


    Cadophora malorum Mo12 was isolated from the Rainbow hydrothermal site on the Mid-Atlantic Ridge. We present the draft genome sequence of this filamentous fungal strain, which has high biotechnological potentials as revealed by the presence of genes encoding biotechnologically important enzymes and genes involved in the synthesis of secondary metabolites. PMID:27389260

  20. Melanin Production by a Filamentous Soil Fungus in Response to Copper and Localization of Copper Sulfide by Sulfide-Silver Staining

    Caesar-Tonthat, T.; Van Ommen, Kloeke F.; Geesey, G. G.; Henson, J M


    Gaeumannomyces graminis var. graminis, a filamentous soil ascomycete, exhibited enhanced cell wall melanin accumulation when exposed to as little as 0.01 mM CuSO(inf4) in minimal broth culture. Because its synthesis was inhibited by tricyclazole, the melanin produced in response to copper was dihydroxynaphthalene melanin. An additional hyphal cell wall layer was visualized by electron microscopy when hyphae were grown in the presence of copper and fixed by cryotechniques. This electron-dense ...

  1. 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.

    Sabine Gruber

    Full Text Available 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.

  2. Adapting High-Resolution Respirometry to Glucose-Limited Steady State Mycelium of the Filamentous Fungus Penicillium ochrochloron: Method Development and Standardisation.

    Schinagl, Christoph W; Vrabl, Pamela; Burgstaller, Wolfgang


    Fungal electron transport systems (ETS) are branched, involving alternative NADH dehydrogenases and an alternative terminal oxidase. These alternative respiratory enzymes were reported to play a role in pathogenesis, production of antibiotics and excretion of organic acids. The activity of these alternative respiratory enzymes strongly depends on environmental conditions. Functional analysis of fungal ETS under highly standardised conditions for cultivation, sample processing and respirometric assay are still lacking. We developed a highly standardised protocol to explore in vivo the ETS-and in particular the alternative oxidase-in Penicillium ochrochloron. This included cultivation in glucose-limited chemostat (to achieve a defined and reproducible physiological state), direct transfer without any manipulation of a broth sample to the respirometer (to maintain the physiological state in the respirometer as close as possible to that in the chemostat), and high-resolution respirometry (small sample volume and high measuring accuracy). This protocol was aimed at avoiding any changes in the physiological phenotype due to the high phenotypic plasticity of filamentous fungi. A stable oxygen consumption (transfer of a broth sample into the respirometer. Steady state respiration was 29% below its maximum respiratory capacity. Additionally to a rotenone-sensitive complex I and most probably a functioning complex III, the ETS of P. ochrochloron also contained a cyanide-sensitive terminal oxidase (complex IV). Activity of alternative oxidase was present constitutively. The degree of inhibition strongly depended on the sequence of inhibitor addition. This suggested, as postulated for plants, that the alternative terminal oxidase was in dynamic equilibrium with complex IV-independent of the rate of electron flux. This means that the onset of activity does not depend on a complete saturation or inhibition of the cytochrome pathway. PMID:26771937

  3. Anaerobes beyond anaerobic digestion

    Sousa, D. Z.; Pereira, M A; Alves, M.M.


    Anaerobic microorganisms are widespread in nature. Sediments, gastrointestinal tracks, volcanic vents, geothermal sources are examples of habitats where anaerobic metabolism prevail, in some cases at extreme temperature, pH and pressure conditions. In such microbial ecosystems waste of some is food for others in a true integrated structure. Anaerobic microorganisms are able to use a wide variety of organic and inorganic compounds. Recalcitrant compounds, such as hydrocarbons, a...

  4. Fungus Amongus

    Wakeley, Deidra


    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…

  5. Crossing Filaments

    Filippov, Boris


    Solar filaments show the position of large scale polarity inversion lines and are used for the reconstruction of large-scale solar magnetic field structure on the basis of H{\\alpha} synoptic charts for the periods when magnetographic measurements were not available. Sometimes crossing filaments are seen in H{\\alpha} filtergrams. We analyze daily H{\\alpha} filtergrams from the archive of Big Bear Solar Observatory for the period of 1999-2003 to find crossing and interacting filaments. A number of examples are presented and filament patterns are compared with photospheric magnetic field distributions. We have found that all crossing filaments reveal quadrupolar magnetic configurations of the photospheric field and presume the presence of null points in the corona.

  6. Helical filaments

    Barbieri, Nicholas; Lim, Khan; Durand, Magali; Baudelet, Matthieu; Richardson, Martin [Townes Laser Institute, CREOL—The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816 (United States); Hosseinimakarem, Zahra; Johnson, Eric [Micro-Photonics Laboratory – Center for Optical Material Science, Clemson, Anderson, South Carolina 29634 (United States)


    The shaping of laser-induced filamenting plasma channels into helical structures by guiding the process with a non-diffracting beam is demonstrated. This was achieved using a Bessel beam superposition to control the phase of an ultrafast laser beam possessing intensities sufficient to induce Kerr effect driven non-linear self-focusing. Several experimental methods were used to characterize the resulting beams and confirm the observed structures are laser air filaments.

  7. Xylanases of Anaerobic Fungus Anaeromyces mucronatus

    Novotná, Zuzana; Procházka, J.; Šimůnek, Jiří; Fliegerová, Kateřina


    Roč. 55, č. 4 (2010), s. 363-367. ISSN 0015-5632 R&D Projects: GA ČR GD525/08/H060 Institutional research plan: CEZ:AV0Z50450515 Keywords : NEOCALLIMASTIX-FRONTALIS * XYLANOLYTIC ENZYMES * POLYCENTRIC FUNGI Subject RIV: GM - Food Processing Impact factor: 0.977, year: 2010

  8. Filamentous cyanobacteria

    Komárek, Jiří; Komárková, J.; Kling, H.

    San Diego: Academic Press pro Elsevier Science, 2003 - (Wehr, J.; Sheath, R.), s. 117-196 ISBN 0-12-741550-5 R&D Projects: GA AV ČR KSK6005114 Keywords : filamentous cyanobacteria * freshwater algae * North America Subject RIV: EF - Botanics

  9. Enhancing aspergiolide A production from a shear-sensitive and easy-foaming marine-derived filamentous fungus Aspergillus glaucus by oxygen carrier addition and impeller combination in a bioreactor.

    Cai, Menghao; Zhou, Xiangshan; Lu, Jian; Fan, Weimin; Niu, Chuanpeng; Zhou, Jiushun; Sun, Xueqian; Kang, Li; Zhang, Yuanxing


    Production enhancement of a novel antitumor compound aspergiolide A from shear-sensitive and easy-foaming marine-derived fungus Aspergillus glaucus HB1-19 in a 5-l stirred bioreactor was investigated. Two types of impellers, i.e., six-flat-blade disc turbine impeller (DT) and three-sector-blade pitched blade turbine impeller (PB) were used in this work. In cultures with fermentation medium, the combination of upper PB and lower DT led to the maximum dry biomass (13.8 g/l) and aspergiolide A production (19.3 mg/l). However, two PBs brought the highest aspergiolide A yield coefficient (1.9 mg/g dry biomass) despite it produced the lowest dry biomass (5.3 g/l). By contrast, two DTs and the upper DT and lower PB showed insignificant results. Feeding 0.35% (v/v) n-dodecane in cultures with upper PB and lower DT further improved aspergiolide A production by 31.0%, i.e., 25.3 mg/l, which is also 322% higher than that in the ordinary cultures with two DTs. PMID:21074418

  10. Triggering filamentation using turbulence

    Eeltink, D; Marchiando, N; Hermelin, S; Gateau, J; Brunetti, M; Wolf, J P; Kasparian, J


    We study the triggering of single filaments due to turbulence in the beam path for a laser of power below the filamenting threshold. Turbulence can act as a switch between the beam not filamenting and producing single filaments. This 'positive' effect of turbulence on the filament probability, combined with our observation of off-axis filaments suggests the underlying mechanism is modulation instability caused by transverse perturbations. We hereby experimentally explore the interaction of modulation instability and turbulence, commonly associated with multiple-filaments, in the single-filament regime.

  11. Filamentous Fungi.

    Powers-Fletcher, Margaret V; Kendall, Brian A; Griffin, Allen T; Hanson, Kimberly E


    Filamentous mycoses are often associated with significant morbidity and mortality. Prompt diagnosis and aggressive treatment are essential for good clinical outcomes in immunocompromised patients. The host immune response plays an essential role in determining the course of exposure to potential fungal pathogens. Depending on the effectiveness of immune response and the burden of organism exposure, fungi can either be cleared or infection can occur and progress to a potentially fatal invasive disease. Nonspecific cellular immunity (i.e., neutrophils, natural killer [NK] cells, and macrophages) combined with T-cell responses are the main immunologic mechanisms of protection. The most common potential mold pathogens include certain hyaline hyphomycetes, endemic fungi, the Mucorales, and some dematiaceous fungi. Laboratory diagnostics aimed at detecting and differentiating these organisms are crucial to helping clinicians make informed decisions about treatment. The purpose of this chapter is to provide an overview of the medically important fungal pathogens, as well as to discuss the patient characteristics, antifungal-therapy considerations, and laboratory tests used in current clinical practice for the immunocompromised host. PMID:27337469

  12. Endocytosis in filamentous fungi

    Kalkman, Edward R I C


    Endocytosis is little understood in filamentous fungi. For some time it has been controversial as to whether endocytosis occurs in filamentous fungi. A comparative genomics analysis between Saccharomyces cerevisiae and 10 genomes of filamentous fungal species showed that filamentous fungi possess complex endocytic machineries. The use of the endocytic marker dye FM4-64, and various vesicle trafficking inhibitors revealed many similarities between endocytosis in the filamentous ...

  13. Gamma radiation effects on the frequency of toxigenic fungus on sene (Cassia angustifolia) and green tea (Camelia sinensis) samples

    The levels of contamination and gamma radiation effects were analyzed in the reduction of toxigenic filamentous fungus in two types of medicinal plants. Aspergillus and Penicillium were the predominant genders and 73,80% of the samples showed high levels of fungus contamination

  14. Anaerobic bacteria

    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 ...

  15. Filamentous Fungi Fermentation

    Nørregaard, Anders; Stocks, Stuart; Woodley, John;


    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...

  16. An intron-containing glycoside hydrolase family 9 cellulase gene encodes the dominant 90 kDa component of the cellulosome of the anaerobic fungus Piromyces sp. strain E2.

    Steenbakkers, Peter J M; Ubhayasekera, Wimal; Goossen, Harry J A M; van Lierop, Erik M H M; van der Drift, Chris; Vogels, Godfried D; Mowbray, Sherry L; Op den Camp, Huub J M


    The cellulosome produced by Piromyces sp. strain E2 during growth on filter paper was purified by using an optimized cellulose-affinity method consisting of steps of EDTA washing of the cellulose-bound protein followed by elution with water. Three dominant proteins were identified in the cellulosome preparation, with molecular masses of 55, 80 and 90 kDa. Treatment of cellulose-bound cellulosome with a number of denaturing agents was also tested. Incubation with 0.5% (w/v) SDS or 8 M urea released most cellulosomal proteins, while leaving the greater fraction of the 80, 90 and 170 kDa components. To investigate the major 90 kDa cellulosome protein further, the corresponding gene, cel9A, was isolated, using immunoscreening and N-terminal sequencing. Inspection of the cel9A genomic organization revealed the presence of four introns, allowing the construction of a consensus for introns in anaerobic fungi. The 2800 bp cDNA clone contained an open reading frame of 2334 bp encoding a 757-residue extracellular protein. Cel9A includes a 445-residue glycoside hydrolase family 9 catalytic domain, and so is the first fungal representative of this large family. Both modelling of the catalytic domain as well as the activity measured with low level expression in Escherichia coli indicated that Cel9A is an endoglucanase. The catalytic domain is succeeded by a putative beta-sheet module of 160 amino acids with unknown function, followed by a threonine-rich linker and three fungal docking domains. Homology modelling of the Cel9A dockerins suggested that the cysteine residues present are all involved in disulphide bridges. The results presented here are used to discuss evolution of glycoside hydrolase family 9 enzymes. PMID:12071852

  17. Increased enzyme production under liquid culture conditions in the industrial fungus Aspergillus oryzae by disruption of the genes encoding cell wall α-1,3-glucan synthase.

    Miyazawa, Ken; Yoshimi, Akira; Zhang, Silai; Sano, Motoaki; Nakayama, Mayumi; Gomi, Katsuya; Abe, Keietsu


    Under liquid culture conditions, the hyphae of filamentous fungi aggregate to form pellets, which reduces cell density and fermentation productivity. Previously, we found that loss of α-1,3-glucan in the cell wall of the fungus Aspergillus nidulans increased hyphal dispersion. Therefore, here we constructed a mutant of the industrial fungus A. oryzae in which the three genes encoding α-1,3-glucan synthase were disrupted (tripleΔ). Although the hyphae of the tripleΔ mutant were not fully dispersed, the mutant strain did form smaller pellets than the wild-type strain. We next examined enzyme productivity under liquid culture conditions by transforming the cutinase-encoding gene cutL1 into A. oryzae wild-type and the tripleΔ mutant (i.e. wild-type-cutL1, tripleΔ-cutL1). A. oryzae tripleΔ-cutL1 formed smaller hyphal pellets and showed both greater biomass and increased CutL1 productivity compared with wild-type-cutL1, which might be attributable to a decrease in the number of tripleΔ-cutL1 cells under anaerobic conditions. PMID:27442340

  18. Heme biosynthesis and regulation in the filamentous fungus Aspergillus niger

    Franken, Adriana Cornelia Wilhelmina


    Cellulose makes up one of the most abundant renewable materials, present in all kinds of plant biomass (Pauly and Keegstra 2010). However, to be able to utilize the cellulose as feedstock, it needs to be separated from lignin which cements the cellulose and hemi-cellulose fibers. Lignolytic peroxida

  19. The genome sequence of the filamentous fungus Neurospora crassa

    Read, Nick D; et al.


    Neurospora crassa is a central organism in the history of twentieth-century genetics, biochemistry and molecular biology. Here, we report a high-quality draft sequence of the N. crassa genome. The approximately 40-megabase genome encodes about 10,000 protein-coding genes—more than twice as many as in the fission yeast Schizosaccharomyces pombe and only about 25% fewer than in the fruitfly Drosophila melanogaster. Analysis of the gene set yields insights into unexpected aspects of Neu...

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

    Wernars, K.


    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, trp C and arg B from A.nidulans ) and heterologous ( pyr 4 from N.crassa ) origin became available transformation procedures for A.nidulans were developed (Ballance et al. 1983; Tilburn et al. 1983; Yelton et al. 1984; John and Pederby 1984). T...

  1. Efficient cellulase production by the filamentous fungus Acremonium cellulolyticus.

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


    Cellulase production was investigated in a culture of a strain of Acremonium cellulolyticus. The medium components were optimized for the improvement of cellulase production. The maximum production of cellulolytic enzymes was obtained in a medium containing (grams per liter) 50 Solka Floc, 5 (NH4)2SO4, 24 KH2PO4, 4.7 potassium tartrate hemihydrate, 1.2 MgSO4.7H2O, 1 Tween 80, 4 urea, 0.01 ZnSO4.7H2O, 0.01 MnSO4.6H2O, and 0.01 CuSO4.7H2O, with a pH of 4.0. In the flask culture, 15.5 filter paper units (FPU)/mL of maximum cellulase activity was obtained, 17.42 FPU/mL in a 7-L bioreactor, and 13.08 FPU/mL in a 50-L scale bioreactor for 4-8 d at 30 degrees C. Average production rates were 1.94 FPU/mL.d in flasks, 2.86 FPU/mL.d in the 7-L bioreactor, and 2.56 FPU/mL.d in the 50-L bioreactor. Cellulase production on a small scale was successfully reproduced in the 50-L pilot scale bioreactor. Saccharification activity from A. cellulolyticus was compared with cellulolytic enzymes produced by other strains. The A. cellulolyticus culture broth had a comparable saccharification yield in comparison with those of other Trichoderma enzymes (GC220 or Cellulosin T2) under the same total cellulase activity. Its saccharification yield (percent of released reducing sugar to used dried substrate) was 60%, and its glucose content was 83%. PMID:17253723

  2. Studies on Laccase Activity in the Filamentous Fungus Trichoderma reesei

    Sekme, Semra; Atacı, Neşe; Arısan, İnci


    Laccase have been mainly studied in wood rot fungal species of the basidiomycetes family especiallyin white rot fungi. Studies in other fungal families are largely lacking. This study has evaluated laccaseactivity fromTrichoderma reesei in catechol based medium. Results showed that laccase enzyme from T.reesei was active in acidic pH range and that optimum pH was 4.5. The optimum temperature oflaccase from T. reesei was also 270C. Laccase activity in medium containing 10 gL-1 catechol was 1.2...

  3. Tremella with Edible Fungus


    (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.

  4. Ethanol effect on metabolic activity of the ethalogenic fungus Fusarium oxysporum

    Paschos, Thomas; Xiros, Charilaos; Christakopoulos, Paul


    Background Fusarium oxysporum is a filamentous fungus which has attracted a lot of scientific interest not only due to its ability to produce a variety of lignocellulolytic enzymes, but also because it is able to ferment both hexoses and pentoses to ethanol. Although this fungus has been studied a lot as a cell factory, regarding applications for the production of bioethanol and other high added value products, no systematic study has been performed concerning its ethanol tolerance levels. Re...

  5. Solar Features - Prominences and Filaments - Filaments

    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)

  6. Anaerobic workout

    McAdam, Ewan J.


    Anaerobic technology cannot directly replace current wastewater treatment processes exclusively. The UASB reactor configuration removes slightly less organic carbon by comparison as the process relies on lamella separation for passive clarification rather than using fine pores like anMBR. By contrast, whilst anMBR can operate as a single unit process for organic carbon removal, the membrane surface has to be cleaned using gas sparging to limit surface deposition, which requires extra energy. ...

  7. Filamentous influenza viruses

    Dadonaite, Bernadeta; Vijyakrishnan, Swetha; Fodor, Ervin; Bhella, David; Hutchinson, Edward C.


    Clinical isolates of influenza virus produce pleomorphic virus particles, including extremely long filamentous virions. In contrast, strains of influenza that have adapted to laboratory growth typically produce only spherical virions. As a result, the filamentous phenotype has been overlooked in most influenza virus research. Recent advances in imaging and improved animal models have highlighted the distinct structure and functional relevance of filamentous virions. In this review we summaris...

  8. Covert connection of filaments

    Filippov, Boris


    We analyse the relationship between two near filaments, which do not show any connection in H-alpha images but reveal close magnetic connectivity during filament activations in Extreme Ultraviolet (EUV) observations. A twisted flux rope, which connects a half of one filament with another filament, becomes visible during several activations but seems to exist all the time of the filaments presence on the disc. Solar Dynamic Observatory} (SDO) and Solar Terrestrial Relations Observatory (STEREO) observed the region with the filaments from two points of view separated by the angle of about 120 deg. On 2012 July 27, SDO observed the filament activation on disc, while for the STEREO B position the filaments were visible at the limb. Nearly identical interaction episode was observed on 2012 August 04 by STEREO A on disc and by SDO at the limb. This good opportunity allows us to disentangle the 3-D shape of the connecting flux rope and in particular to determine with high reliability the helicity sign of the flux ro...

  9. Tungsten filament fire

    Ruiz, Michael J.; Perkins, James


    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 light bulb is being replaced by compact fluorescent and LED lamps.

  10. Regulation of the Cyanide-Resistant Alternative Respiratory Pathway in the Fungus Acremonium chrysogenum

    Sándor, Erzsébet; Fekete, Erzsébet; Karaffa, Levente


    This review summarises the current knowledge on the biochemical and physiological events that directly or indirectly alter the engagement of the cyanide-resistant alternative respiratory pathway in the cephalosporin C producer filamentous fungus Acremonium chrysogenum. Particular emphasis is placed on the role this activity plays in the overproduction of antibiotic, and also on the critical fermentation technology background that supports its operation.

  11. Anaerobic thermophiles.

    Canganella, Francesco; Wiegel, Juergen


    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 to the Archaea has definitely

  12. Anaerobic Thermophiles

    Francesco Canganella


    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

  13. Blistering of viscoelastic filaments

    Sattler, R; Wagner, C


    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.

  14. Femtosecond Laser Filamentation

    Chin, See Leang


    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 ...

  15. The Neurospora crassa genome opens up the world of filamentous fungi

    Hynes, Michael J.


    The filamentous fungus Neurospora crassa, which has played an important role in the development of modern genetics, has several unique genome-defense mechanisms, including a process called repeat-induced point mutation. The draft genome sequence has revealed several unusual features, which suggest that the evolution of N. crassa has been greatly influenced by these defense mechanisms.

  16. Quadrantids filaments modeling

    Rosaev, Alex


    Numeric integration of orbits of particles along mean orbit of Quadrantid meteor stream is done at time span 20000 years. Orbits are subdivided on several classes by their evolution type. A very complex dynamical behavior is detected. About 20% of modeled particles escape stream: this fact point on that stream cannot be long-live and have a source within 5000 years. After that, Quadrantid filaments dynamics are studied. By comparison of different authors data, 7 independent filaments are sele...

  17. Anaerobic Digestion: Process

    Angelidaki, Irini; Batstone, Damien J.


    Organic waste may degrade anaerobically in nature as well as in engineered systems. The latter is called anaerobic digestion or biogasification. Anaerobic digestion produces two main outputs: An energy-rich gas called biogas and an effluent. The effluent, which may be a solid as well as liquid 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....

  18. Nonparametric Filament Estimation

    Genovese, Christopher R; verdinelli, Isabella; Wasserman, Larry


    We develop nonparametric methods for estimating filamentary structure from planar point process data and find the minimax lower bound for this problem. We show that, under weak conditions, the filaments have a simple geometric representation as the medial axis of the data distribution's support. Our methods convert an estimator of the support's boundary into an estimator of the filaments. We find the rates of convergence of our estimators and show that when using an optimal boundary estimator, they achieve the minimax rate. Our work can be regarded as providing a solution to the manifold learning problem as well as being a new approach to principal curve estimation.

  19. Aerogel-supported filament

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


    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.

  20. Lens tilting effect on filamentation and filament-induced fluorescence

    Kamali, Y.; Sun, Q.; Daigle, J.-F.; Azarm, A.; Bernhardt, J.; Chin, S. L.


    In filament-induced fluorescence spectroscopy, we experimentally found that if the lens used for the creation and localization of filament is tilted, the signal to noise ratio of spectral measurement increases. Further study shows that with lens tilting, astigmatism occurs and the filament is split into shorter parts. In turn the shortening of filament reduces the generation of white light which is the major 'noise' source of the spectra.

  1. Branching of keratin intermediate filaments.

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


    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. PMID:27039023

  2. Positrusion Filament Recycling System Project

    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...

  3. Solar Features - Prominences and Filaments

    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...

  4. Cryopreservation of Filamentous Fungi

    Homolka, Ladislav

    New York: Nova Science Publishers, Inc, 2013 - (Colvert, A.; Coty, H.), s. 1-66 ISBN 978-1-62618-474-9 R&D Projects: GA ČR GAP504/12/0709 Institutional support: RVO:61388971 Keywords : cryopreservation * filamentous fungi Subject RIV: EE - Microbiology, Virology

  5. Solid friction between soft filaments

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


    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...

  6. Filament heater current modulation for increased filament lifetime

    The surface conversion H-minus ion source employs two 60 mil tungsten filaments which are approximately 17 centimeters in length. These filaments are heated to approximately 2,800 degrees centigrade by 95--100 amperes of DC heater current. The arc is struck at a 120 hertz rate, for 800 microseconds and is generally run at 30 amperes peak current. Although sputtering is considered a contributing factor in the demise of the filament, evaporation is of greater concern. If the peak arc current can be maintained with less average heater current, the filament evaporation rate for this arc current will diminish. In the vacuum of an ion source, the authors expect the filaments to retain much of their heat throughout a 1 millisecond (12% duty) loss of heater current. A circuit to eliminate 100 ampere heater currents from filaments during the arc pulse was developed. The magnetic field due to the 100 ampere current tends to hold electrons to the filament, decreasing the arc current. By eliminating this magnetic field, the arc should be more efficient, allowing the filaments to run at a lower average heater current. This should extend the filament lifetime. The circuit development and preliminary filament results are discussed

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

    Panagiotou, Gianni; Christakopoulos, Paul; Grotkjær, Thomas;


    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...

  8. Efficient xylose fermentation by the brown rot fungus Neolentinus lepideus.

    Okamoto, Kenji; Kanawaku, Ryuichi; Masumoto, Masaru; Yanase, Hideshi


    The efficient production of bioethanol on an industrial scale requires the use of renewable lignocellulosic biomass as a starting material. A limiting factor in developing efficient processes is identifying microorganisms that are able to effectively ferment xylose, the major pentose sugar found in hemicellulose, and break down carbohydrate polymers without pre-treatment steps. Here, a basidiomycete brown rot fungus was isolated as a new biocatalyst with unprecedented fermentability, as it was capable of converting not only the 6-carbon sugars constituting cellulose, but also the major 5-carbon sugar xylose in hemicelluloses, to ethanol. The fungus was identified as Neolentinus lepideus and was capable of assimilating and fermenting xylose to ethanol in yields of 0.30, 0.33, and 0.34 g of ethanol per g of xylose consumed under aerobic, oxygen-limited, and anaerobic conditions, respectively. A small amount of xylitol was detected as the major by-product of xylose metabolism. N. lepideus produced ethanol from glucose, mannose, galactose, cellobiose, maltose, and lactose with yields ranging from 0.34 to 0.38 g ethanol per g sugar consumed, and also exhibited relatively favorable conversion of non-pretreated starch, xylan, and wheat bran. These results suggest that N. lepideus is a promising candidate for cost-effective and environmentally friendly ethanol production from lignocellulosic biomass. To our knowledge, this is the first report on efficient ethanol fermentation from various carbohydrates, including xylose, by a naturally occurring brown rot fungus. PMID:22226194

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

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


    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.

  10. Gender comparisons in anaerobic power and anaerobic capacity tests.

    Maud, P. J.; Shultz, B B


    The purpose of the study was to compare anaerobic power and anaerobic capacity test scores between young active men and women. Three performance measures of anaerobic power and two of anaerobic capacity were administered to a sample comprising 52 male and 50 female college students (means age = 21.4 yrs). Results indicated significant differences between men and women in body height, weight and per cent fat, in fat free mass (FFM), anaerobic power, and anaerobic capacity when recorded as gros...

  11. CVD-produced boron filaments

    Wawner, F. E.; Debolt, H. E.; Suplinskas, R. D.


    A technique for producing boron filaments with an average tensile strength of 6.89 GPa has been developed which involves longitudinal splitting of the filament and core (substrate) removal by etching. Splitting is accomplished by a pinch wheel device which continuously splits filaments in lengths of 3.0 m by applying a force to the side of the filament to create a crack which is then propagated along the axis by a gentle sliding action. To facilitate the splitting, a single 10 mil tungsten substrate is used instead of the usual 0.5 mil substrate. A solution of hot 30% hydrogen peroxide is used to remove the core without attacking the boron. An alternative technique is to alter the residual stress by heavily etching the filament. Average strengths in the 4.83-5.52 GPa range have been obtained by etching an 8 mil filament to 4 mil.

  12. Filament Identification through Mathematical Morphology

    Koch, Eric W


    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...

  13. REN1 is required for development of microconidia and macroconidia, but not of chlamydospores, in the plant pathogenic fungus Fusarium oxysporum.

    Ohara, Toshiaki; Inoue, Iori; Namiki, Fumio; Kunoh, Hitoshi; Tsuge, Takashi


    The filamentous fungus Fusarium oxysporum is a soil-borne facultative parasite that causes economically important losses in a wide variety of crops. F. oxysporum exhibits filamentous growth on agar media and undergoes asexual development producing three kinds of spores: microconidia, macroconidia, and chlamydospores. Ellipsoidal microconidia and falcate macroconidia are formed from phialides by basipetal division; globose chlamydospores with thick walls are formed acrogenously from hyphae or ...

  14. Mycelial pellet formation by edible ascomycete filamentous fungi, Neurospora intermedia.

    Nair, Ramkumar B; Lennartsson, Patrik R; Taherzadeh, Mohammad J


    Pellet formation of filamentous fungi in submerged culture is an imperative topic of fermentation research. In this study, we report for the first time the growth of filamentous ascomycete fungus, Neurospora intermedia in its mycelial pellet form. In submerged culture, the growth morphology of the fungus was successfully manipulated into growing as pellets by modifying various cultivation conditions. Factors such as pH (2.0-10.0), agitation rate (100-150 rpm), carbon source (glucose, arabinose, sucrose, and galactose), the presence of additive agents (glycerol and calcium chloride) and trace metals were investigated for their effect on the pellet formation. Of the various factors screened, uniform pellets were formed only at pH range 3.0-4.0, signifying it as the most influential factor for N. intermedia pellet formation. The average pellet size ranged from 2.38 ± 0.12 to 2.86 ± 0.38 mm. The pellet formation remained unaffected by the inoculum type used and its size showed an inverse correlation with the agitation rate of the culture. Efficient glucose utilization was observed with fungal pellets, as opposed to the freely suspended mycelium, proving its viability for fast-fermentation processes. Scale up of the pelletization process was also carried out in bench-scale airlift and bubble column reactors (4.5 L). PMID:27103628

  15. Soliton on thin vortex filament

    Showing that one of the equations found by Wadati, Konno and Ichikawa is equivalent to the equation of motion of a thin vortex filament, we investigate solitons on the vortex filament. N vortex soliton solution is given in terms of the inverse scattering method. We examine two soliton collision processes on the filament. Our analysis provides the theoretical foundation of two soliton collision processes observed numerically by Aref and Flinchem. (author)

  16. Solar Filament Extraction and Characterizing

    Yuan, Yuan; Shih, F. Y.; Jing, J.; Wang, H.


    This paper presents a new method to extract and characterize solar filaments from H-alpha full-disk images produced by Big Bear Solar Observatory. A cascading Hough Transform method is designed to identify solar disk center location and radius. Solar disks are segmented from the background, and unbalanced illumination on the surface of solar disks is removed using polynomial surface fitting. And then a localized adaptive thresholding is employed to extract solar filament candidates. After the removal of small solar filament candidates, the remaining larger candidates are used as the seeds of region growing. The procedure of region growing not only connects broken filaments but also generate complete shape for each filament. Mathematical morphology thinning is adopted to produce the skeleton of each filament, and graph theory is used to prune branches and barbs to get the main skeleton. The length and the location of the main skeleton is characterized. The proposed method can help scientists and researches study the evolution of solar filament, for instance, to detect solar filament eruption. The presented method has already been used by Space Weather Research Lab of New Jersey Institute of Technology ( to generate the solar filament online catalog using H-alpha full-disk images of Global H-alpha Network (

  17. Chaperonin filaments: The archael cytoskeleton

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


    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.

  18. Perspectives for anaerobic digestion

    Ahring, Birgitte Kiær


    to the soil. Anaerobic digestion (AD) is one way of achieving this goal and it will furthermore, reduce energy consumption or may even be net energy producing. This chapter aims at provide a basic understanding of the world in which anaerobic digestion is operating today. The newest process developments...

  19. Anaerobic sludge granulation

    Hulshoff Pol, L.W.; Castro Lopes, de S.I.; Lettinga, G.; Lens, P.N.L.


    This paper reviews different theories on anaerobic sludge granulation in UASB-reactors that have been proposed during the past two decades
    This paper reviews different theories on anaerobic sludge granulation in UASB-reactors that have been proposed during the past two decades. The initial stage

  20. Noncatalytic docking domains of cellulosomes of anaerobic fungi.

    Steenbakkers, P J; Li, X L; Ximenes, E A; Arts, J G; Chen, H; Ljungdahl, L G; Op Den Camp, H J


    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

  1. Resonantly enhanced filamentation in gases

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


    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.

  2. Anaerobic Digestion and its Applications

    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...

  3. The link between CMEs, filaments and filament channels

    S. F. Martin


    Full Text Available We present a broad concept for the build-up to eruptive solar events which needs to be tested in future observational and theoretical research. In this concept an eruptive solar event consists of a coronal mass ejection, a filament eruption, a cavity around the filament, and a flare. In our picture, the initial energy source must be external to this eruptive system but also feed into it. Among all eruptive events the common denominator is a filament channel with canceling magnetic fields along a primary polarity reversal boundary. We find that magnetic reconnection at or close to the photosphere is the only interpretation of canceling fields to date that is consistent with observations of filament channels. This reconnection serves to transfer magnetic flux from the photosphere into the chromosphere and corona along polarity reversal boundaries and concurrently initiates the building of a filament channel. Magnetic flux, in excess of that needed to sustain the filament channel, goes into building a filament magnetic field that is always aligned with the polarity reversal boundary and the channel magnetic field. The filament magnetic field remains separated from overarching coronal magnetic fields by the magnetic field of the cavity. The magnetic flux being transported upward from the photosphere/chromosphere carries streams of plasma into the corona along the filament magnetic field. However, the flowing and counterstreaming filament mass also slowly drains out of the field and thereby leaves behind new strands of cavity magnetic field with little or no associated mass. When the build-up of magnetic pressure in the filament and cavity magnetic fields exceeds that of the overlying coronal loops, the coronal loops, the filament and the cavity together begin an observable slow rise which can last a few hours to many days before rapid onset and ejection with a solar flare. We suggest that this process can be accelerated by any number of external

  4. Activity Cycle of Solar Filaments

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


    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).

  5. Laser Filament Induced Water Condensation

    Kasparian J.; Webe K.; Vogel A; Petit Y.; Lüder J.; Hao Z.Q.; Rohwetter P.; Petrarca M.; Stelmaszczyk K.; Henin S.; Wöste L.; Wolf J.-P.


    At relative humidities above 70%, femtosecond laser filaments generate aerosol particles and water droplets in the atmosphere. The water vapour condensation and droplet stabilization are assured by soluble species produced in the laser plasma.

  6. Microcyle Conidiation in Filamentous Fungi

    Jung, Boknam; Kim, Soyeon; Lee, Jungkwan


    The typical life cycle of filamentous fungi commonly involves asexual sporulation after vegetative growth in response to environmental factors. The production of asexual spores is critical in the life cycle of most filamentous fungi. Normally, conidia are produced from vegetative hyphae (termed mycelia). However, fungal species subjected to stress conditions exhibit an extremely simplified asexual life cycle, in which the conidia that germinate directly generate further conidia, without formi...

  7. Sexual reproduction and mating-type–mediated strain development in the penicillin-producing fungus Penicillium chrysogenum

    Böhm, Julia; Hoff, Birgit; O'Gorman, Céline M.; Wolfers, Simon; Klix, Volker; Binger, Danielle; Zadra, Ivo; Kürnsteiner, Hubert; Pöggeler, Stefanie; Dyer, Paul S.; Kück, Ulrich


    Penicillium chrysogenum is a filamentous fungus of major medical and historical importance, being the original and present-day industrial source of the antibiotic penicillin. The species has been considered asexual for more than 100 y, and despite concerted efforts, it has not been possible to induce sexual reproduction, which has prevented sexual crosses being used for strain improvement. However, using knowledge of mating-type (MAT) gene organization, we now describe conditions under which ...

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

    Miller, Mark S; Tanner, Bertrand C. W.; Lori R. Nyland; Vigoreaux, Jim O.


    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 mechanica...

  9. Boolean gates on actin filaments

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


    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.

  10. Droplets engulfing on a filament

    Wu, Xiang-Fa; Yu, Meng; Zhou, Zhengping; Bedarkar, Amol; Zhao, Youhao


    Two immiscible droplets wetting on a filament may assume engulfing, partial-engulfing, or non-engulfing morphology that depends on the wetting behavior and geometries of the resulting droplet-on-filament system. This paper studies the wetting behavior of two immiscible droplets contacting and sitting symmetrically on a straight filament. A set of ordinary differential equations (ODEs) is formulated for determining the wetting morphology of the droplet-on-filament system. In the limiting case of engulfing or non-engulfing, the morphology of the droplet-on-filament system is determined in explicit form. In the case of partial-engulfing, surface finite element method is further employed for determining the wetting morphology, surface energy, and internal pressures of droplets of the system. Numerical scaling study is performed to explore their dependencies upon the wetting properties and geometries of the system. The study can be applicable for analysis and design of textiles with tailorable wetting properties and development of novel multifunctional fibrous materials for environmental protection such as oil-spill sorption, etc.

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

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


    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.

  12. Social-insect fungus farming

    Aanen, Duur Kornelis; Boomsma, Jacobus Jan


    Which social insects rear their own food? Growing fungi for food has evolved twice in social insects: once in new-world ants about 50 million years ago; and once in old-world termites between 24 and 34 million years ago [1] and [2] . The termites domesticated a single fungal lineage - the extant...... basidiomycete genus Termitomyces - whereas the ants are associated with a larger diversity of fungal lineages (all basidiomycetes). The ants and termites forage for plant material to provision their fungus gardens. Their crops convert this carbon-rich plant material into nitrogen-rich fungal biomass to provide...

  13. Temperature Controlled Filamentation in Argon Gas

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


    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.

  14. Cloning and Characterization of Filamentous Fungal S-Nitrosoglutathione Reductase from Aspergillus nidulans.

    Zhou, Yao; Zhou, Shengmin; Yu, Haijun; Li, Jingyi; Xia, Yang; Li, Baoyi; Wang, Xiaoli; Wang, Ping


    S-Nitrosoglutathione reductase (GSNOR) metabolizes S-nitrosoglutathione (GSNO) and has been shown to play important roles in regulating cellular signaling and formulating host defense by modulating intracellular nitric oxide levels. The enzyme has been found in bacterial, yeast, mushroom, plant, and mammalian cells. However, to date, there is still no evidence of its occurrence in filamentous fungi. In this study, we cloned and investigated a GSNOR-like enzyme from the filamentous fungus Aspergillus nidulans. The enzyme occurred in native form as a homodimer and exhibited low thermal stability. GSNO was an ideal substrate for the enzyme. The apparent Km and kcat values were 0.55 mM and 34,100 min(-1), respectively. Substrate binding sites and catalytic center amino acid residues based on those from known GSNORs were conserved in this enzyme, and the corresponding roles were verified using site-directed mutagenesis. Therefore, we demonstrated the presence of GSNOR in a filamentous fungus for the first time. PMID:26869606

  15. Anaerobic biotransformation of estrogens

    Czajka, Cynthia P. [Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada); Londry, Kathleen L. [Department of Microbiology, University of Manitoba, Winnipeg, MB, R3T 2N2 (Canada)]. E-mail:


    Estrogens are important environmental contaminants that disrupt endocrine systems and feminize male fish. We investigated the potential for anaerobic biodegradation of the estrogens 17-{alpha}-ethynylestradiol (EE2) and 17-{beta}-estradiol (E2) in order to understand their fate in aquatic and terrestrial environments. Cultures were established using lake water and sediment under methanogenic, sulfate-, iron-, and nitrate-reducing conditions. Anaerobic degradation of EE2 (added at 5 mg/L) was not observed in multiple trials over long incubation periods (over three years). E2 (added at 5 mg/L) was transformed to estrone (E1) under all four anaerobic conditions (99-176 {mu}g L{sup -1} day{sup -1}), but the extent of conversion was different for each electron acceptor. The oxidation of E2 to E1 was not inhibited by E1. Under some conditions, reversible inter-conversion of E2 and E1 was observed, and the final steady state concentration of E2 depended on the electron-accepting condition but was independent of the total amount of estrogens added. In addition, racemization occurred and E1 was also transformed to 17-{alpha}-estradiol under all but nitrate-reducing conditions. Although E2 could be readily transformed to E1 and in many cases 17-{alpha}-estradiol under anaerobic conditions, the complete degradation of estrogens under these conditions was minimal, suggesting that they would accumulate in anoxic environments.

  16. The anaerobic digestion process

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


    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.

  17. [Cutaneous mold fungus granuloma from Ulocladium chartarum].

    Altmeyer, P; Schon, K


    Cutaneous granulomas due to the mold fungus Ulocladium chartarum (Preuss) are described in a 58 year old woman. This fungus is usually harmless for mammalian. It is thought that a consisting immunosuppression (Brill-Symmer's disease, therapy with corticosteroids) was a priming condition for the infection. The route of infection in this patient described is unknown. PMID:7194869

  18. Anaerobic biological treatment

    The Enso-Fenox process has been very successfully used to remove chlorinated phenolic compounds from pulp bleaching effluents. It is a two-stage anaerobic/aerobic process consisting of a nonmethanogenic anaerobic fluidized bed followed by a trickling filter. Studies have been conducted on reductive dechlorination of chlorinated aromatic compounds under anaerobic conditions with chlorinated phenols as the sole carbon and energy source. Approximately 40% of the added chlorophenols was converted to CH4 and CO2. Substrate loading rates were 20 mg/L/d at hydraulic detention times of 2-4 days with 90% substrate conversion efficiency. Reductive dechlorination of mono, di-, tri-, and pentachlorophenols has been demonstrated in anaerobic sewage sludge. The following constituents were tested in the laboratory at their approximate concentrations in coal conversion wastewater (CCWW) and were anaerobically degraded in serum bottles: 1,000 mg/L phenol; 500 mg/L resorcinol; 1,000 mg/L benzoic acid; 500 mg/L p-cresol; 200 mg/L pyridine; 2,000 mg/L benzoic acid; 250 mg/L 40 methylcatechol; 500 mg/L 4-ethylpyridine; and 2,000 mg/L hexanoic acid. A petrochemical may initially exhibit toxicity to an unacclimated population of methane-fermenting bacteria, but with acclimation the toxicity may be greatly reduced or disappear. In addition, the microorganisms may develop the capacity to actually degrade compounds which showed initial toxicity. Since biomass digestion requires a complete consortium of bacteria, it is relevant to study the effect of a given process as well as to individual steps within the process. A toxicant can inhibit the rate-limiting step and/or change the step that is rate-limiting. Both manifestations of toxicity can severely affect the overall process

  19. Role of Intermediate Filaments in Vesicular Traffic

    Azzurra Margiotta


    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.

  20. Shape Preserving Filament Enhancement Filtering

    Wilkinson, Michael H.F.; Westenberg, Michel A.


    Morphological connected set filters for extraction of filamentous details from medical images are developed. The advantages of these filters are that they are shape preserving and do not amplify noise. Two approaches are compared: (i) multi-scale filtering (ii) single-step shape filtering using conn

  1. Towards filament free semiconductor lasers

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


    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...... propagation structures in lasers and amplifiers which suppress lateral reflections....

  2. Capillary thinning of polymeric filaments

    Kolte, Mette Irene; Szabo, Peter


    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...

  3. Capillary thinning of polymeric filaments

    Kolte, Mette Irene; Szabo, Peter; Hassager, Ole

    The capillary thinning of a polymeric filament is analysed experimentally as well as by means of numerical simulation. The experimental procedure is as follows. Initially a liquid sample is kept between two cylindrical plates. Then the bottom plate is lowered under gravity to yield a given strain...

  4. Towards filament free semiconductor lasers

    McInerney, John; O'Brien, Peter; Skovgaard, Peter M. W.; Mullane, Mark; Houlihan, John; O'Neill, Eamonn; Moloney, Jerome V.; Indik, Robert A.

    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...... propagation structures in lasers and amplifiers which suppress lateral reflections....

  5. Large-scale Motion of Solar Filaments

    Pavel Ambrož; Alfred Schroll


    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.

  6. Current-vortex filaments in magnetized plasmas

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


    Current-vortex filament solutions to the two-fluid plasma equations that describe drift-Alfven waves are presented. Such filament systems are Hamiltonian. Integrable three and four filament systems are discussed in some detail. A wide variety of orbit topologies exists in the plasma case. Special at

  7. Anaerobic azo dye reduction

    Zee, van der, KG Kristoffer


    Azo dyes, aromatic moieties linked together by azo (-N=N-) chromophores, represent the largest class of dyes used in textile-processing and other industries. The release of these compounds into the environment is undesirable, not only because of their colour, but also because many azo dyes and their breakdown products are toxic and/or mutagenic to life. To remove azo dyes from wastewater, a biological treatment strategy based on anaerobic reduction of the azo dyes, followed by aerobic transfo...

  8. Microsatellite primers for fungus-growing ants

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


    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.......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...

  9. Microsatellite Primers for Fungus-Growing Ants

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


    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.......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...

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

    Martin J. Egan


    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.

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

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


    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....

  12. Interaction of light filaments in air

    Xi Ting-Ting; Lu Xin; Hao Zuo-Qiang; Me Yuan-yuan; Zhang Jie


    This paper analytically investigates the interaction of light filaments generated by a femtosecond laser beam in air. It obtains the Hamiltonian of a total laser field and interaction force between two filaments with different phase shifts and crcssing angles. The property of the interaction force, which leads the attraction or repulsion of filaments, is basically dependent on the phase shift between filaments. The crossing angle between two filaments can only determine the magnitude of the interaction force, but does not change the property of the force.

  13. Microwave processing of ceramic oxide filaments

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


    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.

  14. Dynamics of 3D isolated thermal filaments

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


    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.

  15. Calorie restriction causes healthy life span extension in the filamentous fungus Podospora anserina

    Diepeningen, van A.D.; Maas, M.F.P.M.; Huberts, D.H.E.W.; Goedbloed, D.J.; Engelmoer, D.J.P.; Slakhorst, S.M.; Koopmanschap, A.B.; Krause, F.; Dencher, N.A.; Sellem, C.H.; Sainsard-Chanet, A.; Hoekstra, R.F.; Debets, A.J.M.


    Although most fungi appear to be immortal, some show systemic senescence within a distinct time frame. Podospora anserina for example shows an irreversible growth arrest within weeks of culturing associated with a destabilization of the mitochondrial genome. Here, we show that calorie restriction (C

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

    Schoustra, S.E.


    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 economic agents such as multinational firms. According to it, globalisation can be understood as a worldwide reaching 'space of flows' - of money, information, and physical streams - emerging within ...

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

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


    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

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

    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.

  19. An aspartic proteinase gene family in the filamentous fungus Botrytis cinerea contains members with novel features

    Have, ten A.; Dekkers, E.; Kay, J.; Phylip, L.H.; Kan, van J.A.L.


    Botrytis cinerea, an important fungal plant pathogen, secretes aspartic proteinase (AP) activity in axenic cultures. No cysteine, serine or metalloproteinase activity could be detected. Proteinase activity was higher in culture medium containing BSA or wheat germ extract, as compared to minimal medi

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

    Schoustra, S.E.


    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

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

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


    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. PMID:23995938

  2. Filamentation as primitive growth mode?

    Bigan, Erwan; Steyaert, Jean-Marc; Douady, Stéphane


    Osmotic pressure influences cellular shape. In a growing cell, chemical reactions and dilution induce changes in osmolarity, which in turn influence the cellular shape. Using a protocell model relying upon random conservative chemical reaction networks with arbitrary stoichiometry, we find that when the membrane is so flexible that its shape adjusts itself quasi-instantaneously to balance the osmotic pressure, the protocell either grows filamentous or fails to grow. This behavior is consistent with a mathematical proof. This suggests that filamentation may be a primitive growth mode resulting from the simple physical property of balanced osmotic pressure. We also find that growth is favored if some chemical species are only present inside the protocell, but not in the outside growth medium. Such an insulation requires specific chemical schemes. Modern evolved cells such as E. coli meet these requirements through active transport mechanisms such as the phosphotransferase system.

  3. Picosecond laser filamentation in air

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


    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.

  4. New perspectives in anaerobic digestion

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


    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......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...

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

    Rundle William T


    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

  6. Physical properties of interstellar filaments

    Fischera, Joerg; Martin, Peter G.


    We analyze the physical parameters of interstellar filaments that we describe by an idealized model of isothermal self-gravitating infinite cylinder in pressure equilibrium with the ambient medium. Their gravitational state is characterized by the ratio f_cyl of their mass line density to the maximum possible value for a cylinder in a vacuum. Equilibrium solutions exist only for f_cyl < 1. This ratio is used in providing analytical expressions for the central density, the radius, the profile ...

  7. Lighting the universe with filaments.

    Gao, Liang; Theuns, Tom


    The first stars in the universe form when chemically pristine gas heats as it falls into dark-matter potential wells, cools radiatively because of the formation of molecular hydrogen, and becomes self-gravitating. Using supercomputer simulations, we demonstrated that the stars' properties depend critically on the currently unknown nature of the dark matter. If the dark-matter particles have intrinsic velocities that wipe out small-scale structure, then the first stars form in filaments with lengths on the order of the free-streaming scale, which can be approximately 10(20) meters (approximately 3 kiloparsecs, corresponding to a baryonic mass of approximately 10(7) solar masses) for realistic "warm dark matter" candidates. Fragmentation of the filaments forms stars with a range of masses, which may explain the observed peculiar element abundance pattern of extremely metal-poor stars, whereas coalescence of fragments and stars during the filament's ultimate collapse may seed the supermassive black holes that lurk in the centers of most massive galaxies. PMID:17872439

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

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


    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

  9. A new macrocyclic trichochecene from soil fungus


    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.

  10. Anaerobic wastewater treatment using anaerobic baffled bioreactor: a review

    Hassan, Siti; Dahlan, Irvan


    Anaerobic wastewater treatment is receiving renewed interest because it offers a means to treat wastewater with lower energy investment. Because the microorganisms involved grow more slowly, such systems require clever design so that the microbes have sufficient time with the substrate to complete treatment without requiring enormous reactor volumes. The anaerobic baffled reactor has inherent advantages over single compartment reactors due to its circulation pattern that approaches a plug flow reactor. The physical configuration of the anaerobic baffled reactor enables significant modifications to be made; resulting in a reactor which is proficient of treating complex wastewaters which presently require only one unit, ultimately significant reducing capital costs. This paper also concerns about mechanism, kinetic and hydrodynamic studies of anaerobic digestion for future application of the anaerobic baffled reactor for wastewater treatment.

  11. A penny-shaped crack in a filament reinforced matrix. 1: The filament model

    Erdogan, F.; Pacella, A. H.


    The electrostatic problem of a penny-shaped crack in an elastic matrix which reinforced by filaments or fibers perpendicular to the plane of the crack was studied. The elastic filament model was developed for application to evaluation studies of the stress intensity factor along the periphery of the crack, the stresses in the filaments or fibers, and the interface shear between the matrix and the filaments or fibers. The requirements expected of the model are a sufficiently accurate representation of the filament and applicability to the interaction problems involving a cracked elastic continuum with multi-filament reinforcements. The technique for developing the model and numerical examples of it are shown.

  12. Techniques for anaerobic susceptibility testing.

    Thornsberry, C


    Minimal inhibitory concentrations (MICs) of antimicrobial agents for anaerobic bacteria can be determined by agar dilution and broth dilution (including microdilution) techniques. If MICs are not determined routinely, the disk broth or category methods are recommended for routine use. The Bauer-Kirby disk diffusion method and its interpretative standards should not be used for anaerobes. PMID:850089

  13. Anaerobic Digestion of Piggery Waste

    Velsen, van A.F.M.


    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

  14. Economic viability of anaerobic digestion

    Wellinger, A. [INFOENERGIE, Ettenhausen (Switzerland)


    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.

  15. Femtosecond Laser Filamentation for Atmospheric Sensing

    Huai Liang Xu


    Full Text Available Powerful femtosecond laser pulses propagating in transparent materials result in the formation of self-guided structures called filaments. Such filamentation in air can be controlled to occur at a distance as far as a few kilometers, making it ideally suited for remote sensing of pollutants in the atmosphere. On the one hand, the high intensity inside the filaments can induce the fragmentation of all matters in the path of filaments, resulting in the emission of characteristic fluorescence spectra (fingerprints from the excited fragments, which can be used for the identification of various substances including chemical and biological species. On the other hand, along with the femtosecond laser filamentation, white-light supercontinuum emission in the infrared to UV range is generated, which can be used as an ideal light source for absorption Lidar. In this paper, we present an overview of recent progress concerning remote sensing of the atmosphere using femtosecond laser filamentation.

  16. Mechanical properties of branched actin filaments

    Razbin, Mohammadhosein; Benetatos, Panayotis; Zippelius, Annette


    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...

  17. How bio-filaments twist membranes.

    Fierling, Julien; Johner, Albert; Kulić, Igor M; Mohrbach, Hervé; Müller, Martin Michael


    We study the deformations of a fluid membrane imposed by adhering stiff bio-filaments due to the torques they apply. In the limit of small deformations, we derive a general expression for the energy and the deformation field of the membrane. This expression is specialised to different important cases including closed and helical bio-filaments. In particular, we analyse interface-mediated interactions and membrane wrapping when the filaments apply a local torque distribution on a tubular membrane. PMID:27291854

  18. Recent observations of the formation of filaments

    Two examples of the formation of small filaments in H alpha are described and illustrated. In both cases, the formation is seen to be the spontaneous appearance of strands of absorbing mass that evolve from no previous structure. The initial development of the filaments appears to consist of the accumulation of these absorptive strands along approximately parallel paths in a channel between large-scale, opposite polarity magnetic fields on either side of the filaments. The strands exhibit continuous changes in shape and degree of absorption which can be due to successive condensations resulting in new strands, mass motions within the strands, and outflow of the mass from the strands. For at least several hours before the formation of both filaments, small-scale fragments of opposite polarity, line-of-sight magnetic flux adjacent to or immediately below the filaments, and at the ends of the filaments, were cancelling. This type of magnetic flux disappearance continued during the development of the filaments and is commonly observed in association with established filaments. Cancellation is interpreted as an important evolutionary change in the magnetic field that can lead to configurations suitable for the formation of filaments

  19. Probing the Physical Structures of Dense Filaments

    Li, Di


    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.

  20. Methods for modeling cytoskeletal and DNA filaments

    This review summarizes the models that researchers use to represent the conformations and dynamics of cytoskeletal and DNA filaments. It focuses on models that address individual filaments in continuous space. Conformation models include the freely jointed, Gaussian, angle-biased chain (ABC), and wormlike chain (WLC) models, of which the first three bend at discrete joints and the last bends continuously. Predictions from the WLC model generally agree well with experiment. Dynamics models include the Rouse, Zimm, stiff rod, dynamic WLC, and reptation models, of which the first four apply to isolated filaments and the last to entangled filaments. Experiments show that the dynamic WLC and reptation models are most accurate. They also show that biological filaments typically experience strong hydrodynamic coupling and/or constrained motion. Computer simulation methods that address filament dynamics typically compute filament segment velocities from local forces using the Langevin equation and then integrate these velocities with explicit or implicit methods; the former are more versatile and the latter are more efficient. Much remains to be discovered in biological filament modeling. In particular, filament dynamics in living cells are not well understood, and current computational methods are too slow and not sufficiently versatile. Although primarily a review, this paper also presents new statistical calculations for the ABC and WLC models. Additionally, it corrects several discrepancies in the literature about bending and torsional persistence length definitions, and their relations to flexural and torsional rigidities. (topical review)

  1. Chaperonin filaments: The archaeal cytoskeleton?

    Trent, Jonathan D.; Kagawa, Hiromi K.; Yaoi, Takuro; Olle, Eric; Zaluzec, Nestor J.


    Chaperonins are high molecular mass double-ring structures composed of 60-kDa protein subunits. In the hyperthermophilic archaeon Sulfolobus shibatae the two chaperonin proteins represent ≈4% of its total protein and have a combined intracellular concentration of >30 mg/ml. At concentrations ≥ 0.5 mg/ml purified chaperonins form filaments in the presence of Mg2+ and nucleotides. Filament formation requires nucleotide binding (not hydrolysis), and occurs at physiological temperatures in biologically relevant buffers, including a buffer made from cell extracts. These observations suggest that chaperonin filaments may exist in vivo and the estimated 4600 chaperonins per cell suggest that such filaments could form an extensive cytostructure. We observed filamentous structures in unfixed, uranyl-acetate-stained S. shibatae cells, which resemble the chaperonin filaments in size and appearance. ImmunoGold (Janssen) labeling using chaperonin antibodies indicated that many chaperonins are associated with insoluble cellular structures and these structures appear to be filamentous in some areas, although they could not be uranyl-acetate-stained. The existence of chaperonin filaments in vivo suggests a mechanism whereby their protein-folding activities can be regulated. More generally, the filaments themselves may play a cytoskeletal role in Archaea. PMID:9144246

  2. Anaerobic fungal populations

    The development of molecular techniques has greatly broadened our view of microbial diversity and enabled a more complete detection and description of microbial communities. The application of these techniques provides a simple means of following community changes, for example, Ishii et al. described transient and more stable inhabitants in another dynamic microbial system, compost. Our present knowledge of anaerobic gut fungal population diversity within the gastrointestinal tract is based upon isolation, cultivation and observations in vivo. It is likely that there are many species yet to be described, some of which may be non-culturable. We have observed a distinct difference in the ease of cultivation between the different genera, for example, Caecomyes isolates are especially difficult to isolate and maintain in vitro, a feature that is likely to result in the under representation of this genera in culture-based enumerations. The anaerobic gut fungi are the only known obligately anaerobic fungi. For the majority of their life cycles, they are found tightly associated with solid digesta in the rumen and/or hindgut. They produce potent fibrolytic enzymes and grow invasively on and into the plant material they are digesting making them important contributors to fibre digestion. This close association with intestinal digesta has made it difficult to accurately determine the amount of fungal biomass present in the rumen, with Orpin suggesting 8% contribution to the total microbial biomass, whereas Rezaeian et al. more recently gave a value of approximately 20%. It is clear that the rumen microbial complement is affected by dietary changes, and that the fungi are more important in digestion in the rumens of animals fed with high-fibre diets. It seems likely that the gut fungi play an important role within the rumen as primary colonizers of plant fibre, and so we are particularly interested in being able to measure the appearance and diversity of fungi on the plant

  3. Filamentation with nonlinear Bessel vortices.

    Jukna, V; Milián, C; Xie, C; Itina, T; Dudley, J; Courvoisier, F; Couairon, A


    We present a new type of ring-shaped filaments featured by stationary nonlinear high-order Bessel solutions to the laser beam propagation equation. Two different regimes are identified by direct numerical simulations of the nonlinear propagation of axicon focused Gaussian beams carrying helicity in a Kerr medium with multiphoton absorption: the stable nonlinear propagation regime corresponds to a slow beam reshaping into one of the stationary nonlinear high-order Bessel solutions, called nonlinear Bessel vortices. The region of existence of nonlinear Bessel vortices is found semi-analytically. The influence of the Kerr nonlinearity and nonlinear losses on the beam shape is presented. Direct numerical simulations highlight the role of attractors played by nonlinear Bessel vortices in the stable propagation regime. Large input powers or small cone angles lead to the unstable propagation regime where nonlinear Bessel vortices break up into an helical multiple filament pattern or a more irregular structure. Nonlinear Bessel vortices are shown to be sufficiently intense to generate a ring-shaped filamentary ionized channel in the medium which is foreseen as opening the way to novel applications in laser material processing of transparent dielectrics. PMID:25401574

  4. Microcyle conidiation in filamentous fungi.

    Jung, Boknam; Kim, Soyeon; Lee, Jungkwan


    The typical life cycle of filamentous fungi commonly involves asexual sporulation after vegetative growth in response to environmental factors. The production of asexual spores is critical in the life cycle of most filamentous fungi. Normally, conidia are produced from vegetative hyphae (termed mycelia). However, fungal species subjected to stress conditions exhibit an extremely simplified asexual life cycle, in which the conidia that germinate directly generate further conidia, without forming mycelia. This phenomenon has been termed as microcycle conidiation, and to date has been reported in more than 100 fungal species. In this review, first, we present the morphological properties of fungi during microcycle conidiation, and divide microcycle conidiation into four simple categories, even though fungal species exhibit a wide variety of morphological differences during microcycle conidiogenesis. Second, we describe the factors that influence microcycle conidiation in various fungal species, and present recent genetic studies that have identified the genes responsible for this process. Finally, we discuss the biological meaning and application of microcycle conidiation. PMID:24808726

  5. Isolation of pigmentation mutants of the green filamentous photosynthetic bacterium Chloroflexus aurantiacus

    Mutants deficient in the production of bateriochlorophyll c (Bchl c) and one mutant lacking colored carotenoids were isolated from the filamentous gliding bacterium Chloroflexus aurantiacus, Mutagenesis was achieved by using UV radiation or N-methyl-N'-nitro-N-nitrosoguanidine. Several clones were isolated that were deficient in Bchl c synthesis. All reverted. One double mutant deficient both in Bchl c synthesis and in the synthesis of colored carotenoids under anaerobic conditions was isolated. Isolation of a revertant in Bchl c synthesis from this double mutant produced a mutant strain of Chloroflexus that grew photosynthetically under anaerobic conditions and lacked colored carotenoids. Analysis of pigment contents and growth rates of the mutants revealed a positive association between growth rate and content of Bchl c under light-limiting conditions. 11 references, 4 figures, 3 tables

  6. A Statistical Study of Solar Filament Eruptions

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


    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.”

  7. Complete Genome Sequence of the Filamentous Anoxygenic Phototrophic Bacterium Chloroflexus aurantiacus

    Tang, Kuo-Hsiang [Washington University, St. Louis; Barry, Kerrie [U.S. Department of Energy, Joint Genome Institute; Chertkov, Olga [Los Alamos National Laboratory (LANL); Dalin, Eileen [U.S. Department of Energy, Joint Genome Institute; Han, Cliff [Los Alamos National Laboratory (LANL); Hauser, Loren John [ORNL; Honchak, Barbara M [Washington University, St. Louis; Karbach, Lauren E [Washington University, St. Louis; Land, Miriam L [ORNL; Lapidus, Alla L. [Joint Genome Institute, Walnut Creek, California; Larimer, Frank W [ORNL; Mikhailova, Natalia [U.S. Department of Energy, Joint Genome Institute; Pitluck, Sam [Joint Genome Institute, Walnut Creek, California; Pierson, Beverly K [University of Puget Sound, Tacoma, WA


    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.

  8. Characterization of the BLR1 gene encoding a putative blue-light regulator in the phytopathogenic fungus Bipolaris oryzae.

    Kihara, Junichi; Moriwaki, Akihiro; Tanaka, Nozomi; Ueno, Makoto; Arase, Sakae


    Bipolaris oryzae is a filamentous ascomycetous fungus that causes brown leaf spot disease in rice. We isolated and characterized BLR1, a gene that encodes a putative blue-light regulator similar to Neurospora crassa white-collar 1 (WC-1). The deduced amino acid sequence of BLR1 showed high degrees of similarity to other fungal blue-light regulator protein. Disruption of the BLR1 gene demonstrated that this gene is essential for conidial development after conidiophore formation and for near-UV radiation-enhanced photolyase gene expression. PMID:17233721

  9. A First Approach to Filament Dynamics

    Silva, P. E. S.; de Abreu, F. Vistulo; Simoes, R.; Dias, R. G.


    Modelling elastic filament dynamics is a topic of high interest due to the wide range of applications. However, it has reached a high level of complexity in the literature, making it unaccessible to a beginner. In this paper we explain the main steps involved in the computational modelling of the dynamics of an elastic filament. We first derive…

  10. Process for making silver metal filaments

    Bamberger, C.E.


    This invention relates to a process for making filaments of metal compounds and more particularly to a process for making silver metal filaments. The United States Government has rights to this invention pursuant to Contract No. DE-AC05-8421400 with Lockheed Martin Energy Systems, Inc. awarded by the US Department of Energy.

  11. Dentigerumycin: a bacterial mediator of an ant-fungus symbiosis

    Oh, Dong-Chan; Poulsen, Michael; Currie, Cameron R; Clardy, Jon


    Fungus-growing ants engage in mutualistic associations with both the fungus they cultivate for food and actinobacteria (Pseudonocardia spp.) that produce selective antibiotics to defend that fungus from specialized fungal parasites. We have analyzed one such system at the molecular level and found...... that the bacterium associated with the ant Apterostigma dentigerum produces dentigerumycin, a cyclic depsipeptide with highly modified amino acids, to selectively inhibit the associated parasitic fungus (Escovopsis sp.)....

  12. Parotitis due to anaerobic bacteria.

    Matlow, A; Korentager, R; Keystone, E; Bohnen, J


    Although Staphylococcus aureus remains the pathogen most commonly implicated in acute suppurative parotitis, the pathogenic role of gram-negative facultative anaerobic bacteria and strict anaerobic organisms in this disease is becoming increasingly recognized. This report describes a case of parotitis due to Bacteroides disiens in an elderly woman with Sjögren's syndrome. Literature reports on seven additional cases of suppurative parotitis due to anaerobic bacteria are reviewed. Initial therapy of acute suppurative parotitis should include coverage for S. aureus and, in a very ill patient, coverage of gram-negative facultative organisms with antibiotics such as cloxacillin and an aminoglycoside. A failure to respond clinically to such a regimen or isolation of anaerobic bacteria should lead to the consideration of the addition of clindamycin or penicillin. PMID:3287567

  13. Quantifying protein diffusion and capture on filaments

    Reithmann, Emanuel; Frey, Erwin


    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.

  14. Solar Filaments as Tracers of Subsurface Processes

    D. M. Rust


    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.

  15. Particles trajectories in magnetic filaments

    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)


    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.

  16. Filamentous Growth in Eremothecium Fungi

    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....

  17. Particles trajectories in magnetic filaments

    Bret, Antoine


    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.

  18. Natural colorants from filamentous fungi.

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


    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. PMID:26780357

  19. Filamentous fungi as a source of natural antioxidants.

    Smith, Helen; Doyle, Sean; Murphy, Richard


    Ten species of filamentous fungi grown in submerged flask cultures were investigated for antioxidant capacity. Effective antioxidant activity was demonstrated in terms of β-carotene/linoleic acid bleaching, radical scavenging, reduction of metal ions and chelating abilities against ferrous ions. Different extraction methods affected antioxidant activities through their effect on biologically active compounds produced in fungal mycelia. The methanolic extract of each fungus was typically more effective in antioxidant properties. Phenolic content was established in the range of 0.44-9.33 mg/g, flavonoid contents were in the range of 0.02-3.90 mg/g and condensed tannin contents were in the range of 1.77-18.83 mg/g. Total phenol content of each extract was attributed to overall antioxidant capacity (r ⩾ 0.883-1.000). Submerged cultivation of Grifola frondosa, Monascus purpureus, Pleurotus spp., Lentinula edodes and Trametes versicolor proved to be an effective method for the production of natural antioxidants. PMID:25952884

  20. Open-Ended Experimentation with the Fungus Pilobolus.

    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…

  1. [Oxygen consumption by the yeast-like and filamentous forms of Sporothrix schenckii as measured by polarography].

    Tréfouël, M J


    The study of the oxygen uptake by cultures of Sporothrix schenckii as measured with the Clark electrode has shown that when the fungus was grown in a liquid medium, the atmospheric oxygen went into solution very slowly even when the liquid was rapidly stirred. The partial oxygen pressure was very small after some days of culture (no more than 2 or 3% expressed as the saturated value). Hence, it is postulated that the linear part of the growth curve is due to the dissolved oxygen acting as a limiting factor. When the oxygen uptake by filaments, conidia, or yeasts isplotted against the time the curve variations follow the transformations of the fungus. PMID:816527

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

    Li, Ting; Zhang, Jun; Ji, Haisheng


    We conducted a comparative analysis of two filaments that showed a 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) were made to analyze the two filaments on 2013 August 17 - 20 (SOL2013-08-17) and September 29 (SOL2013-09-29). 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 6.4×1021 Mx underlying the filament. The close neighborhood and common direction of the bright threads in the filament and the open AR fan loops suggest a similar magnetic connectivity of these two flux systems. The equilibrium of the filament was not destroyed three 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 4.2×1020 Mx, about one order of magnitude lower than that of the first event. Two patches of parasitic polarity in the vicinity of the barb merged, then cancelled with nearby network fields. About 20 hours after the onset of the emergence, the filament erupted. Our findings imply that the location of emerging flux within the filament channel is probably crucial to filament evolution. If the flux emergence appears nearby the barbs, it is highly likely that the emerging flux and the filament magnetic fields will cancel, which may lead to the eruption of the filament. The comparison of the two events shows that the emergence of a small AR may still not be enough to disrupt the stability of a filament system, and the actual eruption only occurs after the flux cancellation sets in.

  3. Unwinding motion of a twisted active region filament

    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)


    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.

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

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


    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. PMID:26039904

  5. Automatic Detect and Trace of Solar Filaments

    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

  6. Death from Fungus in the Soil


    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.

  7. Spread of Rare Fungus from Vancouver Island


    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.

  8. Optical Filaments and Gas Dynamics in Air

    Yeak, Jeremy

    Until now, the propagation dynamics of intense ultrashort laser pulses leading to optical filamentation in air has only been investigated in the frame of a dynamic balance between linear diffraction, Kerr self-focusing and plasma defocusing. This has led to the development of different theories surrounding the generation and persistence of optical filaments propagating over many Rayleigh lengths in air. These theories include wave-guiding model, moving focus model, dynamic spatial replenishment model and conical wave model. However, these models fail to capture the gas dynamics that arise from optical filaments interacting with air. In this work, we demonstrate that initial conditions are critical to the formation of optical filaments through the use of an aerodynamic window. Filament characteristics in air, such as spectral broadening, electrical conductivity and fluorescence, are measured and presented. Using these as diagnostic tools, we also show that the optical filamentation of ultrashort laser pulses can be enhanced at high repetition rates because of the thermal response of air, resulting from the interaction of each laser pulse with the modified atmospheric density distribution left behind by the preceding pulse. This is explained by the sudden deposition of energy by a filament in the air which generates a cylindrical shock wave, leaving behind a column of rarefied air. This low-density region persists for an extended period and can materially affect the propagation dynamics of an ensuing pulse that follows before the low-density region has relaxed sufficiently to ambient conditions. By further increasing the repetition rate, the onset of ionization is shifted downstream and the spectral continuum displays a stronger broadening on both sides of the original pulse spectrum. This gas dynamic interaction regime of filamentation can be utilized to enhance the length and spectral width of filaments for remote sensing and long range laser-induced high voltage

  9. Automatic filament warm-up controller

    Mccluskey, J.; Daeges, J.


    As part of the unattended operations objective of the Deep Space Network deep space stations, this filament controller serves as a step between manual operation of the station and complete computer control. Formerly, the operator was required to devote five to fifteen minutes of his time just to properly warm up the filaments on the klystrons of the high power transmitters. The filament controller reduces the operator's duty to a one-step command and is future-compatible with various forms of computer control.

  10. System Applies Polymer Powder To Filament Tow

    Baucom, Robert M.; Snoha, John J.; Marchello, Joseph M.


    Polymer powder applied uniformly and in continuous manner. Powder-coating system applies dry polymer powder to continuous fiber tow. Unique filament-spreading technique, combined with precise control of tension on fibers in system, ensures uniform application of polymer powder to web of spread filaments. Fiber tows impregnated with dry polymer powders ("towpregs") produced for preform-weaving and composite-material-molding applications. System and process valuable to prepreg industry, for production of flexible filament-windable tows and high-temperature polymer prepregs.

  11. Genome sequence of a novel mycovirus of Rhizoctonia solani, a plant pathogenic fungus.

    Zhong, Jie; Chen, Chuan-Yuan; Gao, Bi-Da


    Here we present the genome sequence of a novel dsRNA virus we designed as Rhizoctonia solani RNA virus HN008 (RsRV-HN008) from a filamentous fungus R. solani. Its genome (7596 nucleotides) contains two non-overlapping open reading frames (ORF1 and ORF2). ORF1 encoded a 128 kDa protein that showed no significant identity to any other virus sequence in the NCBI database. ORF2 encoded a protein with a molecular weight of 140 kDa and shared a low percentage of sequence identity to the RdRps of unclassified dsRNA viruses. Sequence analysis revealed that RsRV-HN008 may be a member of a novel unclassified family of mycoviruses. PMID:26116286

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

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


    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 ...

  13. Iron biomineralization by anaerobic neutrophilic iron-oxidizing bacteria

    Miot, Jennyfer; Benzerara, Karim; Morin, Guillaume; Kappler, Andreas; Bernard, Sylvain; Obst, Martin; Férard, Céline; Skouri-Panet, Fériel; Guigner, Jean-Michel; Posth, Nicole; Galvez, Matthieu; Brown, Gordon E., Jr.; Guyot, François


    Minerals formed by bio-oxidation of ferrous iron (Fe(II)) at neutral pH, their association with bacterial ultrastructures as well as their impact on the metabolism of iron-oxidizing bacteria remain poorly understood. Here, we investigated iron biomineralization by the anaerobic nitrate-dependent iron-oxidizing bacterium Acidovorax sp. strain BoFeN1 in the presence of dissolved Fe(II) using electron microscopy and Scanning Transmission X-ray Microscopy (STXM). All detected minerals consisted mainly of amorphous iron phosphates, but based on their morphology and localization, three types of precipitates could be discriminated: (1) mineralized filaments at distance from the cells, (2) globules of 100 ± 25 nm in diameter, at the cell surface and (3) a 40-nm thick mineralized layer within the periplasm. All of those phases were shown to be intimately associated with organic molecules. Periplasmic encrustation was accompanied by an accumulation of protein moieties. In the same way, exopolysaccharides were associated with the extracellular mineralized filaments. The evolution of cell encrustation was followed by TEM over the time course of a culture: cell encrustation proceeded progressively, with rapid precipitation in the periplasm (in a few tens of minutes), followed by the formation of surface-bound globules. Moreover, we frequently observed an asymmetric mineral thickening at the cell poles. In parallel, the evolution of iron oxidation was quantified by STXM: iron both contained in the bacteria and in the extracellular precipitates reached complete oxidation within 6 days. While a progressive oxidation of Fe in the bacteria and in the medium could be observed, spatial redox (oxido-reduction state) heterogeneities were detected at the cell poles and in the extracellular precipitates after 1 day. All these findings provide new information to further the understanding of molecular processes involved in iron biomineralization by anaerobic iron-oxidizing bacteria and

  14. Filament overwrapped motor case technology

    Compton, Joel P.


    Atlantic Research Corporation (ARC) joined with the French Societe Europeenne de Propulsion (SEP) to develop and deliver to the U.S. Navy a small quantity of composite filament wound rocket motors to demonstrate a manufacturing technique that was being applied at the two companies. It was perceived that the manufacturing technique could produce motors that would be light in weight, inexpensive to produce, and that had a good chance of meeting insensitive munitions (IM) requirements that were being formulated by the Navy in the early 1980s. Under subcontract to ARC, SEP designed, tested, and delivered 2.75-inch rocket motors to the U.S. Navy for IM tests that were conducted in 1989 at China Lake, California. The program was one of the first to be founded by Nunn Amendment money. The Government-to-Government program was sponsored by the Naval Air Systems Command and was monitored by the Naval Surface Warfare Center, Indian Head (NSWC-IH), Maryland. The motor propellant that was employed was a new, extruded composite formulation that was under development at the Naval Surface Warfare Center. The following paper describes the highlights of the program and gives the results of structural and ballistic static tests and insensitive munitions tests that were conducted on demonstration motors.

  15. Pressure effects on the femtosecond laser filamentation

    Qi, Xiexing; Ma, Cunliang; Lin, Wenbin


    We investigate the pressure effects on the propagation of the laser pulse with wavelength of 800 nm by numerical simulations. We consider the effects on the on-axis intensity, the beam radius and the energy of the filament, as well as the on-axis density of plasma. Numerical results show that when the pressures increase, the length, radius and energy of the light filament become shorter, narrower and lower, respectively. Moreover, we find that the length and the radius of filament are approximately inversely proportional to the pressure and the square root of pressure, respectively, and the pulse with shorter duration is easier to be affected by the pressure. We also obtain the conclusion that the plasma is not necessary to generate the filament in gases in various pressures, as stated by Béjot et al. [1] for the case of standard atmosphere pressure.

  16. Intermediate filaments in small configuration spaces.

    Nöding, Bernd; Köster, Sarah


    Intermediate filaments play a key role in cell mechanics. Apart from their great importance from a biomedical point of view, they also act as a very suitable micrometer-sized model system for semiflexible polymers. We perform a statistical analysis of the thermal fluctuations of individual filaments confined in microchannels. The small channel width and the resulting deflections at the walls give rise to a reduction of the configuration space by about 2 orders of magnitude. This circumstance enables us to precisely measure the intrinsic persistence length of vimentin intermediate filaments and to show that they behave as ideal wormlike chains; we observe that small fluctuations in perpendicular planes decouple. Furthermore, the inclusion of results for confined actin filaments demonstrates that the Odijk confinement regime is valid over at least 1 order of magnitude in persistence length. PMID:22463576

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

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


    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. PMID:25277408

  18. Crystallization, X-ray diffraction analysis and phasing of 17β-hydroxysteroid dehydrogenase from the fungus Cochliobolus lunatus

    The expression, purification and crystallization of 17β-hydroxysteroid dehydrogenase from the filamentous fungus C. lunatus and its Y167F mutant, both in the apo form, are described. X-ray diffraction analysis and phasing by Patterson-search techniques are reported. 17β-Hydroxysteroid dehydrogenase from the filamentous fungus Cochliobolus lunatus (17β-HSDcl) is an NADP(H)-dependent enzyme that preferentially catalyses the oxidoreduction of oestrogens and androgens. The enzyme belongs to the short-chain dehydrogenase/reductase superfamily and is the only fungal hydroxysteroid dehydrogenase known to date. 17β-HSDcl has recently been characterized and cloned and has been the subject of several functional studies. Although several hypotheses on the physiological role of 17β-HSDcl in fungal metabolism have been formulated, its function is still unclear. An X-ray crystallographic study has been undertaken and the optimal conditions for crystallization of 17β-HSDcl (apo form) were established, resulting in well shaped crystals that diffracted to 1.7 Å resolution. The space group was identified as I4122, with unit-cell parameters a = b = 67.14, c = 266.77 Å. Phasing was successfully performed by Patterson search techniques. A catalytic inactive mutant Tyr167Phe was also engineered, expressed, purified and crystallized for functional and structural studies

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

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


    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.

  20. Hoop tensile properties of filament wound pipes

    Srebrenkoska, Vineta; Zhezhova, Silvana; Naseva, Simona


    In this study hoop tensile properties of continuous fiber reinforced composites pipes are investigated. The test pipes were manufactured of glass fiber and epoxy resin by filament winding method with three different winding angle configurations (10°, 45° and 90°). Three specimens from each model of filament wound pipes with help of split-disk tests were tested and the hoop tensile strengths and modulus of elasticity were determined. From received results it is concluded that, mechanical prope...

  1. A Robust Actin Filaments Image Analysis Framework.

    Alioscha-Perez, Mitchel; Benadiba, Carine; Goossens, Katty; Kasas, Sandor; Dietler, Giovanni; Willaert, Ronnie; Sahli, Hichem


    The cytoskeleton is a highly dynamical protein network that plays a central role in numerous cellular physiological processes, and is traditionally divided into three components according to its chemical composition, i.e. actin, tubulin and intermediate filament cytoskeletons. Understanding the cytoskeleton dynamics is of prime importance to unveil mechanisms involved in cell adaptation to any stress type. Fluorescence imaging of cytoskeleton structures allows analyzing the impact of mechanical stimulation in the cytoskeleton, but it also imposes additional challenges in the image processing stage, such as the presence of imaging-related artifacts and heavy blurring introduced by (high-throughput) automated scans. However, although there exists a considerable number of image-based analytical tools to address the image processing and analysis, most of them are unfit to cope with the aforementioned challenges. Filamentous structures in images can be considered as a piecewise composition of quasi-straight segments (at least in some finer or coarser scale). Based on this observation, we propose a three-steps actin filaments extraction methodology: (i) first the input image is decomposed into a 'cartoon' part corresponding to the filament structures in the image, and a noise/texture part, (ii) on the 'cartoon' image, we apply a multi-scale line detector coupled with a (iii) quasi-straight filaments merging algorithm for fiber extraction. The proposed robust actin filaments image analysis framework allows extracting individual filaments in the presence of noise, artifacts and heavy blurring. Moreover, it provides numerous parameters such as filaments orientation, position and length, useful for further analysis. Cell image decomposition is relatively under-exploited in biological images processing, and our study shows the benefits it provides when addressing such tasks. Experimental validation was conducted using publicly available datasets, and in osteoblasts grown in

  2. A Robust Actin Filaments Image Analysis Framework

    Alioscha-Perez, Mitchel; Benadiba, Carine; Goossens, Katty; Kasas, Sandor; Dietler, Giovanni; Willaert, Ronnie; Sahli, Hichem


    The cytoskeleton is a highly dynamical protein network that plays a central role in numerous cellular physiological processes, and is traditionally divided into three components according to its chemical composition, i.e. actin, tubulin and intermediate filament cytoskeletons. Understanding the cytoskeleton dynamics is of prime importance to unveil mechanisms involved in cell adaptation to any stress type. Fluorescence imaging of cytoskeleton structures allows analyzing the impact of mechanical stimulation in the cytoskeleton, but it also imposes additional challenges in the image processing stage, such as the presence of imaging-related artifacts and heavy blurring introduced by (high-throughput) automated scans. However, although there exists a considerable number of image-based analytical tools to address the image processing and analysis, most of them are unfit to cope with the aforementioned challenges. Filamentous structures in images can be considered as a piecewise composition of quasi-straight segments (at least in some finer or coarser scale). Based on this observation, we propose a three-steps actin filaments extraction methodology: (i) first the input image is decomposed into a ‘cartoon’ part corresponding to the filament structures in the image, and a noise/texture part, (ii) on the ‘cartoon’ image, we apply a multi-scale line detector coupled with a (iii) quasi-straight filaments merging algorithm for fiber extraction. The proposed robust actin filaments image analysis framework allows extracting individual filaments in the presence of noise, artifacts and heavy blurring. Moreover, it provides numerous parameters such as filaments orientation, position and length, useful for further analysis. Cell image decomposition is relatively under-exploited in biological images processing, and our study shows the benefits it provides when addressing such tasks. Experimental validation was conducted using publicly available datasets, and in osteoblasts

  3. Laser filament-induced aerosol formation

    Saathoff, H.; Henin, S.; Stelmaszczyk, K.; Petrarca, M.; Delagrange, R.; Hao, Z.; Lüder, J.; Möhler, O.; Y. Petit; Rohwetter, P.; Schnaiter, M.; Kasparian, J.; Leisner, T.; J.-P. Wolf; Wöste, L.


    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 partic...

  4. Laser filament-induced aerosol formation

    Saathoff, H.; Henin, S.; Stelmaszczyk, K.; Petrarca, M.; Delagrange, R.; Hao, Z.; Lüder, J.; Möhler, O.; Y. Petit; Rohwetter, P.; Schnaiter, M.; Kasparian, J.; Leisner, T.; J.-P. Wolf; Wöste, L.


    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 parti...

  5. Laser filament-induced aerosol formation

    Saathoff, H.; Henin, S.; Stelmaszczyk, K.; Petrarca, M.; Delagrange, R.; Hao, Z.; Lüder, J.; Möhler, O.; Y. Petit; Rohwetter, P.; Schnaiter, M.; Kasparian, J.; Leisner, T.; Wolf, J.-P.; Wöste, L.


    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...

  6. Theory of swimming filaments in viscoelastic media

    Fu, Henry C.; Powers, Thomas R.; Wolgemuth, Charles W.


    Motivated by the swimming of sperm in the non-Newtonian fluids of the female mammalian reproductive tract, we examine the swimming of filaments in the nonlinear viscoelastic Upper Convected Maxwell model. We obtain the swimming velocity and hydrodynamic force exerted on an infinitely long cylinder with prescribed beating pattern. We use these results to examine the swimming of a simplified sliding-filament model for a sperm flagellum. Viscoelasticity tends to decrease swimming speed, and chan...

  7. Anaerobic digestion of solid material

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


    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 simulated...... improve the continuous flow reactor performance at the relatively low influent methanogenic biomass concentration. In the continuously stirred tank reactor (CSTR) there are two steady states with and without methane production at slightly different values of initial methanogenic biomass concentration....... In the system, the threshold methanogenic biomass concentration existed because of inhibition by high VFA concentration. High methanogenic biomass concentration is required for efficient anaerobic digestion of MSW in order to avoid possible inhibition due to high VFA build-up. Thus, CSTR configuration might...


    M. S. Tabib


    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.

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

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


    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. PMID:25737119

  10. Filaments in the Lupus molecular clouds

    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


    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.