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Thomson GJ, Kakade P, Hirakawa MP, Ene IV, Bennett RJ. Adaptation to the dietary sugar D-tagatose via genome instability in polyploid Candida albicans cells. G3-GENES GENOMES GENETICS 2021; 11:6219300. [PMID: 33836061 PMCID: PMC8495922 DOI: 10.1093/g3journal/jkab110] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2021] [Accepted: 03/25/2021] [Indexed: 02/06/2023]
Abstract
The opportunistic fungal pathogen Candida albicans undergoes an unusual parasexual cycle wherein diploid cells mate to form tetraploid cells that can generate genetically diverse progeny via a non-meiotic program of chromosome loss. The genetic diversity afforded by parasex impacts clinically relevant features including drug resistance and virulence, and yet the factors influencing genome instability in C. albicans are not well defined. To understand how environmental cues impact genome instability, we monitored ploidy change following tetraploid cell growth in a panel of different carbon sources. We found that growth in one carbon source, D-tagatose, led to high levels of genomic instability and chromosome loss in tetraploid cells. This sugar is a stereoisomer of L-sorbose which was previously shown to promote karyotypic changes in C. albicans. However, while expression of the SOU1 gene enabled utilization of L-sorbose, overexpression of this gene did not promote growth in D-tagatose, indicating differences in assimilation of the two sugars. In addition, genome sequencing of multiple progeny recovered from D-tagatose cultures revealed increased relative copy numbers of chromosome 4, suggestive of chromosome-level regulation of D-tagatose metabolism. Together, these studies identify a novel environmental cue that induces genome instability in C. albicans, and further implicate chromosomal changes in supporting metabolic adaptation in this species.
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Affiliation(s)
- Gregory J Thomson
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
| | - Pallavi Kakade
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
| | - Matthew P Hirakawa
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA.,Department of Systems Biology, Sandia National Laboratories, Livermore, CA 94550, USA
| | - Iuliana V Ene
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA.,Mycology Department, Pasteur Institute, Paris 75015, France
| | - Richard J Bennett
- Department of Molecular Microbiology and Immunology, Brown University, Providence, RI 02912, USA
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Spanu F, Scherm B, Camboni I, Balmas V, Pani G, Oufensou S, Macciotta N, Pasquali M, Migheli Q. FcRav2, a gene with a ROGDI domain involved in Fusarium head blight and crown rot on durum wheat caused by Fusarium culmorum. MOLECULAR PLANT PATHOLOGY 2018; 19:677-688. [PMID: 28322011 PMCID: PMC6638036 DOI: 10.1111/mpp.12551] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Revised: 03/02/2017] [Accepted: 03/13/2017] [Indexed: 06/06/2023]
Abstract
Fusarium culmorum is a soil-borne fungal pathogen which causes foot and root rot and Fusarium head blight on small-grain cereals, in particular wheat and barley. It causes significant yield and quality losses and results in the contamination of kernels with type B trichothecene mycotoxins. Our knowledge of the pathogenicity factors of this fungus is still limited. A transposon tagging approach based on the mimp1/impala double-component system has allowed us to select a mutant altered in multiple metabolic and morphological processes, trichothecene production and virulence. The flanking regions of mimp1 were used to seek homologies in the F. culmorum genome, and revealed that mimp1 had reinserted within the last exon of a gene encoding a hypothetical protein of 318 amino acids which contains a ROGDI-like leucine zipper domain, supposedly playing a protein-protein interaction or regulatory role. By functional complementation and bioinformatic analysis, we characterized the gene as the yeast Rav2 homologue, confirming the high level of divergence in multicellular fungi. Deletion of FcRav2 or its orthologous gene in F. graminearum highlighted its ability to influence a number of functions, including virulence, trichothecene type B biosynthesis, resistance to azoles and resistance to osmotic and oxidative stress. Our results indicate that the FcRav2 protein (and possibly the RAVE complex as a whole) may become a suitable target for new antifungal drug development or the plant-mediated resistance response in filamentous fungi of agricultural interest.
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Affiliation(s)
- Francesca Spanu
- Dipartimento di AgrariaUniversità degli Studi di SassariSassariI‐07100Italy
| | - Barbara Scherm
- Dipartimento di AgrariaUniversità degli Studi di SassariSassariI‐07100Italy
| | - Irene Camboni
- Dipartimento di AgrariaUniversità degli Studi di SassariSassariI‐07100Italy
| | - Virgilio Balmas
- Dipartimento di AgrariaUniversità degli Studi di SassariSassariI‐07100Italy
| | - Giovanna Pani
- Dipartimento di AgrariaUniversità degli Studi di SassariSassariI‐07100Italy
| | - Safa Oufensou
- Dipartimento di AgrariaUniversità degli Studi di SassariSassariI‐07100Italy
- Faculté des Sciences de BizerteZarzouna TN‐7000Tunisia
| | - Nicolo’ Macciotta
- Dipartimento di AgrariaUniversità degli Studi di SassariSassariI‐07100Italy
| | - Matias Pasquali
- Dipartimento di Scienze per gli Alimenti la Nutrizione, l'AmbienteUniversità di MilanoMilanoI‐20133Italy
| | - Quirico Migheli
- Dipartimento di AgrariaUniversità degli Studi di SassariSassariI‐07100Italy
- Unità di Ricerca Istituto Nazionale di Biostrutture e BiosistemiSassariI‐07100Italy
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Production and secretion of a multifunctional ß-glucosidase by Humicola grisea var. thermoidea: effects of L-sorbose. ANN MICROBIOL 2013. [DOI: 10.1007/s13213-013-0748-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Chromosome 5 monosomy of Candida albicans controls susceptibility to various toxic agents, including major antifungals. Antimicrob Agents Chemother 2013; 57:5026-36. [PMID: 23896475 DOI: 10.1128/aac.00516-13] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Candida albicans is a prevailing fungal pathogen with a diploid genome that can adapt to environmental stresses by losing or gaining an entire chromosome or a large portion of a chromosome. We have previously found that the loss of one copy of chromosome 5 (Ch5) allows for adaptation to the toxic sugar l-sorbose. l-Sorbose is similar to caspofungin and other antifungals from the echinocandins class, in that it represses synthesis of cell wall glucan in fungi. Here, we extended the study of the phenotypes controlled by Ch5 copy number. We examined 57 strains, either disomic or monosomic for Ch5 and representing five different genetic backgrounds, and found that the monosomy of Ch5 causes elevated levels of chitin and repressed levels of 1,3-β-glucan components of the cell wall, as well as diminished cellular ergosterol. Increased deposition of chitin in the cell wall could be explained, at least partially, by a 2-fold downregulation of CHT2 on the monosomic Ch5 that encodes chitinase and a 1.5-fold upregulation of CHS7 on Ch1 that encodes the protein required for wild-type chitin synthase III activity. Other important outcomes of Ch5 monosomy consist of susceptibility changes to agents representing four major classes of antifungals. Susceptibility to caspofungin increased or decreased and susceptibility to 5-fluorocytosine decreased, whereas susceptibility to fluconazole and amphotericin B increased. Our results suggest that Ch5 monosomy represents an unrecognized C. albicans regulatory strategy that impinges on multiple stress response pathways.
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Kamei M, Yamashita K, Takahashi M, Fukumori F, Ichiishi A, Fujimura M. Deletion and expression analysis of beta-(1,3)-glucanosyltransferase genes in Neurospora crassa. Fungal Genet Biol 2012; 52:65-72. [PMID: 23274249 DOI: 10.1016/j.fgb.2012.12.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2012] [Revised: 11/30/2012] [Accepted: 12/10/2012] [Indexed: 10/27/2022]
Abstract
GPI(glycosylphosphatidylinositol)-anchored beta-(1,3)-glucanosyltransferases play an active role in cell wall biosynthesis in fungi. Neurospora crassa has 5 putative beta-(1,3)-glucanosyltransferase genes, namely, gel-1, gel-2, gel-3, gel-4, and gel-5, in its genome. Among them, the gel-3 gene is constitutively expressed at the highest level in growing hyphae, whereas gel-1 is expressed at the lowest level. The gel-3 deletion mutant displayed slow growth, while other gel gene disruptants exhibited normal growth. Although no gel gene disruption affected pH sensitivity and fertility, all Δgel mutants were resistant to cell wall degradation enzymes. Micafungin, a beta-(1,3)-glucan synthase inhibitor, induced gel-4 expression in the wild-type and 2 MAP kinase mutants mak-1 and mak-2 strains. In contrast, fludioxonil, an activator of OS-2 MAP kinase, strongly induced the gel-1 gene in the wild-type strain. Its induction was nearly abolished in the os-2 and in the atf-1/asl-1 mutant. These suggested that GEL-3 is a major factor in mycelial growth, while GEL-1 and GEL-4 may play important roles in cell wall remodeling in response to stress conditions or cell wall damage, respectively.
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Affiliation(s)
- Masayuki Kamei
- Toyo University, Itakura, Oura-gun, Gunma 374-0193, Japan
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Schaffner DW, Toledo RT. Cellulase production by Trichoderma reesei when cultured on xylose-based media supplemented with sorbose. Biotechnol Bioeng 2010; 37:12-6. [PMID: 18597302 DOI: 10.1002/bit.260370104] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The ability of L-sorbose to stimulate cellulase production In shake flask culture of Trichoderma reesei was examined in mineral salts media (initial pH 5.0) containing either 1.0% D-xylose, 1.0% cellulose, and/or 0.1, 0.3, or 0.5% L-sorbose. When sorbose was the only carbon source, growth was limited, little substrate was utilized, pH increased, and cellulase activity was not apparent. The other carbon sources promoted good growth, pH dropped sharply to 2.5-3.0, substrate was utilized rapidly, and cellulase activity was detected. After three weeks of fermentation, twice as much cellulase activity was detected in the medium containing only cellulose as the carbon source, as compared to xylose as the carbon source. Cellulase activity was higher when media contained xylose supplemented with sorbose compared to xylose as the only carbon source. At 0.3 and 0.5% levels of sorbose supplementation of xylose-based media, cellulase activity was similar to that in cellulose-based media.
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Affiliation(s)
- D W Schaffner
- Department of Food Science and Technology, University of Georgia, Athens, Georgia 30602, USA
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Gorovits R, Propheta O, Kolot M, Dombradi V, Yarden O. A mutation within the catalytic domain of COT1 kinase confers changes in the presence of two COT1 isoforms and in Ser/Thr protein kinase and phosphatase activities in Neurospora crassa. Fungal Genet Biol 1999; 27:264-74. [PMID: 10441452 DOI: 10.1006/fgbi.1999.1152] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Neurospora crassa grows by forming spreading colonies. cot-1 belongs to a class of N. crassa colonial temperature-sensitive (cot) mutants and encodes a Ser/Thr protein kinase. We have mapped the cot-1 mutation to a single base change resulting in a His to Arg substitution at amino acid 351, which resides within the catalytic domain. Antibodies raised against COT1 detected and immunoprecipitated a predominant 73-kDa polypeptide in N. crassa extracts, whose abundance was constant under all growth conditions tested. An additional, lower MW COT1 isoform (67-kDa) present in the wild-type was not detected in cot-1 grown at the restrictive temperature. Similarly, this isoform was not detected in cot-3 or cot-5 strains, when grown at restrictive temperatures. Reduced levels of Ser/Thr kinase activity and an increase in type 1 and type 2B phosphatase (calcineurin) activities were measured in a cot-1 background. Apparent changes in the phosphorylation state of the p150(Glued) subunit of the dynactin cytoskeletal motor component (encoded by ro-3, a suppressor of cot-1) and evidence of in vitro physical interactions between COT1 and calcineurin indicate a functional linkage among COT1 kinase, type 2B phosphatase, and dynactin.
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Affiliation(s)
- R Gorovits
- Otto Warburg Center for Agricultural Biotechnology, The Hebrew University of Jerusalem, Rehovot, 76100, Israel
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9
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Lauter FR, Marchfelder U, Russo VE, Yamashiro CT, Yatzkan E, Yarden O. Photoregulation of cot-1, a kinase-encoding gene involved in hyphal growth in Neurospora crassa. Fungal Genet Biol 1998; 23:300-10. [PMID: 9680960 DOI: 10.1006/fgbi.1998.1038] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Blue light plays a key role as an environmental signal in the regulation of growth and development of fungi and plants. Here we demonstrate that in Neurospora crassa hyphae branch more frequently in cultures grown in light. Previous studies had identified cot-1 as a gene that controls apical hyphal cell elongation. In the cot-1 mutant, cessation of elongation is accompanied by hyperbranching. Here we demonstrate that the cot-1 gene encodes two transcript species of about 2100 nt (cot-1 (s)) and about 2400 nt (cot-1 (l)) in length and that the ratio of both transcript species abundance is photoregulated. The origin of the difference between cot-1 (l) and cot-1 (s) was localized to the 5' end of the cot-1 transcripts, suggesting that two COT1 isoforms with different activities may be formed. Both light effects, on branching and on cot-1 expression, were dependent on functional wc-1 and wc-2 gene products. In addition to light, L-sorbose comprises another environmental cue that controls hyphal branching in N. crassa. In the presence of L-sorbose, photoregulation of cot-1 was blocked, suggesting the involvement of alternative and potentially interdependent signaling pathways for the regulation of hyphal elongation/branching.
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Affiliation(s)
- F R Lauter
- BioInside GmbH, Teltow bei Berlin, Germany
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10
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Lejeune R, Nielsen J, Baron GV. Morphology ofTrichoderma reesei QM 9414 in submerged cultures. Biotechnol Bioeng 1995; 47:609-15. [DOI: 10.1002/bit.260470513] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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11
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Singh A, Hayashi K. Microbial cellulases: protein architecture, molecular properties, and biosynthesis. ADVANCES IN APPLIED MICROBIOLOGY 1995; 40:1-44. [PMID: 7604736 DOI: 10.1016/s0065-2164(08)70362-9] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- A Singh
- Biomaterials Conversion Laboratory, National Food Research Institute, Ibaraki, Japan
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12
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Optimization of medium for extracellular nuclease formation from Rhizopus stolonifer. World J Microbiol Biotechnol 1993; 9:205-9. [DOI: 10.1007/bf00327838] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Revised: 09/10/1992] [Accepted: 09/16/1992] [Indexed: 10/26/2022]
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13
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Abstract
Glucans are the most abundant polysaccharides present in fungi. The present review provides updated information on the structure and synthesis of beta-glucans in fungal cells. Synthesis of these polymers made up of B1,3 chains with a variable degree of B1,6 branching involves several reactions: initiation, chain elongation and branching, of which the most studied one is the elongation step. This reaction, catalyzed by the so-called glucan synthetases, utilizes UDPG as sugar donor. Properties of glucan synthetases are extremely variable depending on the fungal species, and their developmental stage. Because of the importance of these polysaccharides it is anticipated that comprehension of their mechanism of synthesis, is important for the understanding of cell wall assembly and cell growth and morphogenesis, as well as for the design of specific antifungal drugs.
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Affiliation(s)
- J Ruiz-Herrera
- Departamento de Genética y Biologia Molecular, Centro de Investigación y de Estudios Avanzados del IPN, Irapuato, Gto., México
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Taft CS, Zugel M, Selitrennikoff CP. In vitro inhibition of stable 1,3-beta-D-glucan synthase activity from Neurospora crassa. JOURNAL OF ENZYME INHIBITION 1991; 5:41-9. [PMID: 1669437 DOI: 10.3109/14756369109069059] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Glucan synthase activity of Neurospora crassa was isolated by treatment of protoplast lysates with 0.1% 3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonate and 0.5% octylglucoside in 25 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid buffer, pH 7.4, containing 5 mM EDTA, 1 mM phenylmethylsulfonylfluoride, 200 mM inorganic phosphate, 10 microM GTP, 1 mM DTT, 10 mM sodium fluoride, and 600 mM glycerol. Resulting activity was partially purified by sucrose gradient density sedimentation. Approximately 70% of enzyme activity in the sucrose gradient peak fraction was soluble and enzyme activity was purified 7.3-fold. Partially purified enzyme activity had a half-life of several weeks at 4 degrees C, and a Km(app) of 1.66 +/- 0.28 mM. Inhibitors (Cilofungin, papulacandin B, aculeacin A, echinocandin B, sorbose and UDP) of 1,3-beta-D-glucan synthase activity were tested against crude particulate and detergent treated enzyme fractions and the Ki(app) of each inhibitor determined. It seems likely that this stable preparation of glucan synthase activity may be useful for in vitro enzyme screens for new glucan synthase inhibitors.
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Affiliation(s)
- C S Taft
- Department of Cellular and Structural Biology, University of Colorado Health Sciences Center, Denver 80262
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15
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Phelps P, Stark T, Selitrennikoff CP. Cell wall assembly ofNeurospora crassa: Isolation and analysis of cell wall-less mutants. Curr Microbiol 1990. [DOI: 10.1007/bf02092162] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ruiz-Herrera J, Sentandreu R. Fungal cell wall synthesis and assembly. CURRENT TOPICS IN MEDICAL MYCOLOGY 1989; 3:168-217. [PMID: 2688916 DOI: 10.1007/978-1-4612-3624-5_8] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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18
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Abstract
The cellulase enzyme system consists of cellobiohydrolase, endoglucanase, and beta-glucosidase and has been extensively studied with respect to its biosynthesis, properties, mode of action, application, and, most recently, secretion mechanisms. A knowledge of the factors governing the biosynthesis and secretion of these enzymes at the molecular level will be useful in maximizing enzyme productivity in extracellular fluid. Among other topics, the regulatory effects of sorbose (a noninducing sugar which is not a product of cellulose hydrolysis) on cellulase synthesis and release are described. Cellulase genes have recently been cloned into a number of microorganisms with a view to understanding the gene structure and expression and to obtaining the enzyme components in pure form. The factors governing biosynthesis and secretion of cellulases in recombinant cells are also discussed. Cellulases are known to be glycoproteins, therefore, the role of O- and N-linked glycosylation on enzyme stability and secretion is also detailed.
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Affiliation(s)
- V S Bisaria
- Biochemical Engineering Research Centre, Indian Institute of Technology-Delhi
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19
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Takeuchi Y, Schmid J, Caldwell JH, Harold FM. Transcellular ion currents and extension of Neurospora crassa hyphae. J Membr Biol 1988; 101:33-41. [PMID: 2966862 DOI: 10.1007/bf01872817] [Citation(s) in RCA: 51] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Hyphae of Neurospora crassa, like many other tip-growing organisms, drive endogenous electric currents through themselves such that positive charges flow into the apical region and exit from the trunk. In order to identify the ions that carry the current, the complete growth medium was replaced by media lacking various constituents. Omission of K+ or of phosphate diminished the zone of inward current, effectively shifting the current pattern towards the apex. Omission of glucose markedly reduced both inward and outward currents; addition of sodium azide virtually abolished the flow of electric current. Growing hyphae also generate a longitudinal pH gradient: the medium surrounding the apex is slightly more alkaline than the bulk phase, while medium adjacent to the trunk turns acid. The results suggest that Neurospora hyphae generate a proton current; protons are expelled distally by the H+-ATPase and return into the apical region by a number of pathways, including the symport of protons with phosphate and potassium ions. Calcium influx may also contribute to the electric current that enters the apical region. There seems to be no simple obligatory linkage between the intensity of the transcellular electric current and the rate of hyphal extension. Calcium ions, however, are required in micromolar concentrations for extensions and morphogenesis of hyphal tips.
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Affiliation(s)
- Y Takeuchi
- Department of Molecular and Cellular Biology, National Jewish Center for Immunology and Respiratory Medicine, Denver, Colorado 80206
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Sorbose-resistant mutants ofNeurospora crassa do not have alteredβ(1–3)glucan synthase activity. Curr Microbiol 1987. [DOI: 10.1007/bf01577528] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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Fehér Z, Schablik M, Kiss A, Zsindely A, Szabó G. Characterization of inl+ transformants of Neurospora crassa obtained with a recombinant cosmid-pool. Curr Genet 1986; 11:131-7. [PMID: 2834083 DOI: 10.1007/bf00378205] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
We constructed a Neurospora crassa gene library in a cosmid vector and used the cosmid-pool DNA to transform an inl, rg Neurospora crassa strain to inositol prototrophy. The inl+ colonies obtained in this experiment proved to be integrative type transformants. Genetic analysis revealed that the integration event occurred at or near the inl locus. In one of the transformants the inl+ trait exhibited mitotic and meiotic instability. In hybridization experiments free plasmids were detected in the F1 progeny of the transformants. We were able to recover eleven different plasmids from the F1 progeny of the transformants. None of these plasmids proved to carry a functional copy of the inl+ gene as judged by its transforming ability. Possible explanations for the observed phenomena are discussed.
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Affiliation(s)
- Z Fehér
- Department of Biology, University Medical School, Debrecen, Hungary
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Anné J. Protoplasts of filamentous fungi in genetics and metabolite production. EXPERIENTIA. SUPPLEMENTUM 1983; 46:167-178. [PMID: 6585305 DOI: 10.1007/978-3-0348-6776-4_21] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Fungal protoplasts are interesting structures for genetic studies. They can be fused and their fusion products can revert to osmotic stable cells. The ability to fuse protoplasts of diverse origin makes them versatile tools in fundamental and applied genetics. Intraspecies protoplast fusion provides an efficient method to induce the parasexual cycle, making genetic analysis as well as strain breeding through mitotic recombination feasible in all kinds of species, regardless the occurrence of parasexuality by conventional means. Interspecies protoplast fusion allows the generation of different types of hybrids, depending on somatic and/or nuclear compatibility. Crosses between closely related species resulted in the formation of stable haploid recombinants as the consequence of genetic processes similar as occurring in the intraspecies parasexual cycle. From fusions between less related species hybrid progeny with differences in morphology and stability arose. Unstable hybrids segregated to other hybrid progeny or to one of the parental species, without recovery of the other parent. The exact genetic background of these hybrids remained obscure. Several studies demonstrated that the novel genetic combination arisen after interspecies protoplast fusion could result in changed gene expression and in the synthesis of novel or hybrid molecules.
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McDaniel LL, Hindal DF. Spore Swelling, Germination, and Germ Tube Formation in Axenic Culture Among four Species of Piptocephalis. Mycologia 1982. [DOI: 10.1080/00275514.1982.12021500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Affiliation(s)
- L. L. McDaniel
- Division of Plant and Soil Sciences, College of Agriculture and Forestry, West Virginia University, Morgantown, West Virginia 26506
| | - D. F. Hindal
- Division of Plant and Soil Sciences, College of Agriculture and Forestry, West Virginia University, Morgantown, West Virginia 26506
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Fèvre M, Rougier M. β-1-3- and β-1-4-glucan synthesis by membrane fractions from the fungus Saprolegnia. PLANTA 1981; 151:232-241. [PMID: 24301848 DOI: 10.1007/bf00395174] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/1980] [Accepted: 09/28/1980] [Indexed: 06/02/2023]
Abstract
The β-glucan synthetase activity of the fungus Saprolegnia monoica was assayed by supplying UDP-glucose to membrane fractions of mycelial homogenate. The analysis of glucan products by hydrolysis with various β-glucanases and by chromatography show that both β-1-3- and β-1-4-linkages are formed at high substrate concentrations. In the absence of MgCl2, β-1-3-linked glucans are mainly produced. By increasing MgCl2 concentrations the total synthesis activity and β-1-3-linkages production are reduced. At low substrate concentrations in the presence of MgCl2, β-1-4-linked glucans are the only polysaccharide synthesized. Electron microscopy of radioactive products, synthesized by original membrane fractions or by membrane fractions isolated from continuous sucrose density gradients, shows microfibrils when the assays are conducted at high substrate concentrations in the absence of MgCl2.
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Affiliation(s)
- M Fèvre
- Laboratoire de Physiologie Végétale, Laboratoire de Mycologie associé au C.N.RS. no 44, Université Claude Bernard, 43 Boulevard du 11 Novembre 1918, France
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Fevre M. Digitonin Solubilization and Protease Stimulation of β Glucan Synthetases of Saprolegnia. ACTA ACUST UNITED AC 1979. [DOI: 10.1016/s0044-328x(79)80077-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Abstract
Phenethyl alcohol, m-cresol, and related compounds cause inhibition of germ tube formation in conidia of Neurospora crassa. Conidia continue to swell and form large spherical cells that are capable of multiple germ tube formation upon removal of inhibitor.
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Meyer R, Parish RW, Hohl HR. Hyphal tip growth in Phytophthora. Gradient distribution and ultrahistochemistry of enzymes. Arch Microbiol 1976; 110:215-24. [PMID: 1015947 DOI: 10.1007/bf00690230] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Germinating cysts and isolated walls from germinating cysts incorporated 14C-UDPG into wall material of which 22.5 and 15% respectively were insoluble in boiling 1 N HCl, indicating that part of the synthetase activity is located in the wall itself. A combination of Urografin and Ficoll density gradients was used to separate various intracellular fractions. A consistent separation of beta-glucanase and UDPG-transferase enriched fractions was achieved. The beta-glucanase fraction contained dictyosome vesicles and fragments along with some plasma membranes. The UDPG-transferase fraction was relatively rich in membranes resembling rough and smooth ER. The results suggest the two enzymes are transported to the wall by different intracellular routes, and two types of vesicle may be involved. Alkaline phosphatase, beta-glucosidase and acid phosphatase were found extracellularly and their distribution in density gradients determined. The results of histochemical staining for acid phosphatase, alkaline phosphatase and polysaccharide are described and compared with the biochemical data. beta-1,3-glucanase, found intra- and extracellularly, induced distorted growth of germ tubes and also removed most of the apical wall when added to the incubation medium. None of these responses were observed with cellulase. Determinations of the osmotic pressure of germinating cysts and incubation medium revealed that the turgor of germinating cysts amounts to about 1.8 at under the conditions used.
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Mishra NC. The effect of cyclic adenosine monophosphate on the growth of Neurospora crassa. THE SCIENCE OF NATURE - NATURWISSENSCHAFTEN 1976; 63:485. [PMID: 185527 DOI: 10.1007/bf00624588] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Abstract
The inactivation of Neurospora crassa conidia by galactosaminoglycan isolated from cultures of this organism was followed by measuring colony-forming ability and ability to take up radiolabeled metabolites. When kinetic data on the loss of transport function and on killing were analyzed by use of target theory, it appeared that few "hits" are required for inactivation. However, studies with radio-labeled galactosaminoglycan mucopolysaccharides showed that cells receiving a single lethal hit have approximately 10(5) galactosaminoglycan molecules bound to them.
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Ruiz-Herrera J, Bartnicki-Garcia S. Synthesis of cell wall microfibrils in vitro by a "soluble" chitin synthetase from Mucor rouxii. Science 1974; 186:357-9. [PMID: 4607147 DOI: 10.1126/science.186.4161.357] [Citation(s) in RCA: 72] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
A "soluble" form of chitin synthetase was separated from a membrane-rich fraction by exposure to the enzyme substrate (uridine diphosphate N-acetyl-D-glucosamine) and activator (N-acetyl- D-glucosamine). The solubilized enzyme catalyzed the synthesis of chitin microfibrils similar, if not identical, to those formed in vivo by the fungus. Cell wall microfibrils were thus abundantly formed in the absence of a living cell or its membranes.
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